WO2023127964A1

WO2023127964A1 - Battery module and method for manufacturing same

Info

Publication number: WO2023127964A1
Application number: PCT/JP2022/048658
Authority: WO
Inventors: 英明堀江; 洋志川崎
Original assignee: Ａｐｂ株式会社
Priority date: 2021-12-28
Filing date: 2022-12-28
Publication date: 2023-07-06

Abstract

In this battery module, a battery assembly (11) and a plurality of light emitting units (12) are covered by and accommodated in a gas barrier film (13), which is an exterior body. The gas barrier film (13) has a function of preventing the permeation of various gases such as hydrogen gas generated from electrodes of the battery assembly (11), for example, and as a whole is transparent with respect to optical signals emitted from light emitting elements (42) of the light emitting units (12). The optical signals emitted from the light emitting elements (42) covered by the gas barrier film (13) are received outside a structural body (10) through the gas barrier film (13). According to this battery module, sealing of the battery assembly by means of the exterior body can be implemented while simplifying the internal configuration of the battery module, thereby facilitating assembly.

Description

Battery module and manufacturing method thereof

The present invention relates to a battery module and its manufacturing method.

In recent years, thin batteries such as lithium ion batteries have been used as power sources for electric vehicles, hybrid electric vehicles, etc., and as power sources for mobile electronic devices such as mobile phones and smart phones. A battery module of a lithium ion battery is, for example, an assembled battery in which a plurality of lithium ion single cells having an active material layer and a current collector are stacked, and a film sealing the assembled battery, and an electrode of the assembled battery It is covered with an exterior body made of a gas barrier film that absorbs gas generated from, etc. (see Patent Documents 1 and 2). A laminate film of aluminum or the like is used as the gas barrier film.

Moreover, in a battery module of a lithium ion battery, it is necessary to manage the state of each unit cell that constitutes the assembled battery. For example, when charging an assembled battery, it is necessary to manage charging so that there is no overcharged unit cell. Therefore, a battery module equipped with a transmission/reception unit that transmits and receives the state of each unit cell of the assembled battery by optical signal, and a battery module configured to detect the state of the unit cell with a single light-receiving diode through a common optical fiber are being developed. have been devised (see Patent Documents 3 and 4).
2. Description of the Related Art Conventionally, batteries such as lithium ion secondary batteries have been used as batteries for vehicles, for example. Lithium ion secondary batteries generate heat due to their internal resistance during the process of charging and discharging, and the amount of heat generated is particularly large in large batteries through which large currents pass. Therefore, in order to suppress the temperature rise of the battery, a through hole for air cooling and a through hole for cooling water to obtain a higher cooling effect are provided inside the battery.

Retable 2018/164219 Japanese Patent Publication No. 34-13214 JP-A-11-355904 Japanese Patent No. 3812145

In a battery module of a lithium-ion battery, in order to grasp the state of the single cells that make up the assembled battery, the battery module is provided with a light emitting section that emits an optical signal indicating the state of each single cell. An optical component such as an optical waveguide may be arranged for transmitting the optical signal of the optical signal to the outside. Since the optical component directly receives the optical signal from the optical component inside the exterior body of the battery module and transmits the optical signal to the outside of the exterior body, the optical component includes a front part for receiving the optical signal. In some cases, the rear stage portion, which is arranged inside the battery module armor and propagates the received optical signal, is pulled out of the battery module armor. In this case, not only does the internal configuration of the battery module become complicated, but there is also a concern that the sealing of the assembled battery may be incomplete, which may be one of the causes of fragility of the battery module. It is also not easy to assemble a battery module with such a complicated configuration.

It is an object of the present invention to provide a battery module that can be easily assembled by simplifying the internal configuration of the battery module, sealing the assembled battery with an outer package, and a method for manufacturing the same.

As a result of intensive studies based on the above findings, the inventors came up with the following aspects of the invention.

A battery module according to an aspect of the present invention comprises
A positive electrode current collector including a resin current collector layer; a positive electrode having a positive electrode active material layer including a positive electrode active material formed on the positive electrode current collector; a negative electrode current collector including a resin current collector layer; A plurality of unit cells are stacked each including a negative electrode having a negative electrode active material layer containing a negative electrode active material formed on a current collector, and a separator disposed between the positive electrode active material layer and the negative electrode active material layer. an assembled battery,
a plurality of light emitting units provided for each of the cells and transmitting optical signals based on the state of the cells;
a gas barrier film covering the assembled battery;
and
The gas barrier film as a whole is transparent to the optical signal.

According to the present invention, it is possible to provide a battery module that simplifies the internal configuration of the battery module, allows the assembled battery to be sealed by the exterior body, and can be easily assembled, and a method for manufacturing the same.

FIG. 1 is a schematic perspective view showing the configuration of a battery module of a first embodiment according to a first aspect of the invention. FIG. 2 is a schematic perspective view showing a structure, which is a constituent element of the battery module of the first embodiment according to the first aspect of the invention, with a part of the gas barrier film cut away. FIG. 3 is a schematic cross-sectional view showing only a unit cell that constitutes an assembled battery, which is a constituent element of the battery module of the first embodiment according to the first aspect of the invention. FIG. 4 is a schematic perspective view showing a partly cutaway unit cell provided with a light-emitting portion, which is a constituent element of the battery module of the first embodiment according to the first aspect of the invention. FIG. 5 is a schematic perspective view showing an enlarged view of only the light-emitting portion, which is a constituent element of the battery module of the first embodiment according to the first aspect of the invention. FIG. 6 is a schematic cross-sectional view showing how light guide tubes are arranged in a structure that is a component of the battery module of the first embodiment according to the first aspect of the invention. FIG. 7 is a block diagram schematically showing a circuit configuration including peripheral members of the battery module of the first embodiment according to the first aspect of the invention. FIG. 8A is a schematic diagram showing an example of optical signal patterns when the voltages of the cells are different. FIG. 8B is a schematic diagram showing an example of optical signal patterns when the voltages of the cells are different. FIG. 8C is a schematic diagram showing an example of optical signal patterns when the voltages of the cells are different. FIG. 8D is a schematic diagram showing an example of optical signal patterns when the voltages of the cells are different. FIG. 8E is a schematic diagram showing an example of optical signal patterns when the voltages of the cells are different. FIG. 8F is a schematic diagram showing an example of an optical signal pattern when the temperature of the cell is equal to or higher than a predetermined temperature. FIG. 9 is a schematic diagram showing another example of optical signal patterns when the voltages of the cells are different. FIG. 10A is a schematic diagram showing an example of an optical signal pattern derived from a light guide tube. FIG. 10B is a schematic diagram showing an example of an optical signal pattern derived from a light guide tube. FIG. 10C is a schematic diagram showing an example of an optical signal pattern derived from a light guide tube. FIG. 11 is a schematic perspective view showing how the battery module of the first embodiment is manufactured using a deep drawing vacuum packaging machine. FIG. 12A is a schematic cross-sectional view showing the configuration of the sealing portion of the deep drawing vacuum packaging machine used in the first embodiment according to the first aspect of the invention. FIG. 12B is a schematic cross-sectional view showing the configuration of the sealing portion of the deep drawing vacuum packaging machine used in the first embodiment according to the first aspect of the invention. FIG. 13 is a schematic perspective view showing an exploded battery module manufactured in the first embodiment according to the first aspect of the invention. FIG. 14A is a schematic perspective view showing the configuration of the battery module of the second embodiment according to the first aspect of the invention. FIG. 14B is a schematic perspective view showing an exploded light guide section, which is a constituent element of the battery module of the second embodiment according to the first aspect of the invention. FIG. 14C is a schematic perspective view showing how the light guide section 52 and the light receiving section are attached to the structure in the battery module of the second embodiment according to the first aspect of the invention. FIG. 15A is a schematic perspective view for explaining method 1 for manufacturing a battery module in the second embodiment according to the first aspect of the invention. FIG. 15B is a schematic perspective view for explaining method 2 for manufacturing a battery module in the second embodiment according to the first aspect of the invention. FIG. 15C is a schematic perspective view for explaining method 3 for manufacturing a battery module in the second embodiment according to the first aspect of the invention. FIG. 16A is a partially cutaway perspective view showing a partially exploded configuration of Modification 1 of the battery module of the second embodiment according to the first aspect of the invention. 16B is a partially cutaway perspective view showing the configuration of Modification 1 of the battery module of the second embodiment according to the first aspect of the invention. FIG. FIG. 17 is a schematic cross-sectional view showing the configuration of Modification 2 of the battery module of the second embodiment according to the first aspect of the invention. FIG. 18 is a perspective view showing a secondary battery module according to the second aspect of the invention. FIG. 19 is a side sectional view of a secondary battery module according to the second aspect of the invention. FIG. 20A is an enlarged cross-sectional view of a battery cell as a lithium ion secondary battery. FIG. 20B is a diagram showing an enlarged cross-sectional view of another battery cell as a lithium ion secondary battery. FIG. 21A is a diagram showing an example of forming a positive electrode-side current extraction layer on a positive electrode current collector for a battery cell in a secondary battery module. FIG. 21B is a diagram showing an example of forming a positive electrode-side current extraction layer on a positive electrode current collector for a battery cell in a secondary battery module. FIG. 22 is a diagram showing an example of forming an assembled battery in which a plurality of battery cells are stacked and connected. FIG. 23A is a diagram showing an example in which the positive electrode side current extraction layer is made of a material in which a small hole penetrating from the upper end to the lower end is formed. FIG. 23B is a diagram showing an example in which the positive current extraction layer is made of a material in which a small hole penetrating from the upper end to the lower end is formed. FIG. 24 is a diagram showing an example in which a plurality of battery cells share a negative current supply layer and a positive current extraction layer. FIG. 25 is a perspective view showing an example in which a negative rectifying section and a positive rectifying section are provided in the secondary battery module according to the second aspect of the invention. FIG. 26 is a side sectional view showing an example in which a negative rectifying section and a positive rectifying section are provided in the secondary battery module according to the second aspect of the invention. FIG. 27 is a diagram showing the battery cell portion of the secondary battery module according to the second aspect of the invention with dotted lines. FIG. 28 is a diagram showing the operation of the secondary battery module according to the second aspect of the invention. FIG. 29 is a perspective view showing another example in which a negative rectifying section and a positive rectifying section are provided in the secondary battery module according to the second aspect of the invention. FIG. 30 is a diagram showing an example of mounting a plurality of current extraction portions as conductors, a positive electrode conductive line, and a positive electrode junction portion. FIG. 31 is a plan view of the positive electrode side current extraction layer viewed from above in the third embodiment according to the second aspect of the invention. FIG. 32 is a plan view showing another form of the positive electrode side current extraction layer viewed from above in the third embodiment according to the second aspect of the invention. FIG. 33 is a plan view of the negative electrode side current supply layer viewed from below in the third embodiment according to the second aspect of the invention.

--First aspect of the invention--
First, a battery module and a manufacturing method thereof according to the first aspect of the invention will be described.

Hereinafter, preferred embodiments of the first aspect of the invention will be described in detail with reference to the drawings. Embodiments disclose a battery module of a lithium ion secondary battery and a method of manufacturing the same. Although an example of a lithium ion secondary battery is shown below, the type of secondary battery according to the present invention is not limited to the lithium ion secondary battery, and includes other secondary batteries. Lithium-ion secondary batteries include not only the embodiments described below, but also batteries using a liquid material for the electrolyte and batteries using a solid material for the electrolyte (so-called all-solid-state batteries). In addition, the lithium ion battery in the present embodiment includes a battery having a metal foil (metal current collector foil) as a current collector, and is composed of a resin to which a conductive material is added instead of the metal foil, a so-called resin current collector. Including a battery with a body. When the resin current collector is used as a resin current collector for a bipolar electrode, which will be described later, a positive electrode is formed on one surface of the resin current collector and a negative electrode is formed on the other surface to obtain a bipolar electrode. may be configured. In addition, the lithium ion battery in the present embodiment includes those in which the positive electrode or negative electrode active material or the like is applied to the positive electrode current collector or the negative electrode current collector using a binder to form an electrode, and in the case of a bipolar battery, is a bipolar electrode having a positive electrode layer formed by applying a positive electrode active material or the like using a binder to one surface of a current collector, and a negative electrode layer formed by applying a negative electrode active material or the like using a binder to the opposite surface of the current collector. including those that consist of

<First embodiment>
First, the first embodiment will be described.

[Configuration of battery module]
FIG. 1 is a schematic perspective view showing the configuration of the battery module of the first embodiment. FIG. 2 is a schematic perspective view showing a structure, which is a component of the battery module of FIG. 1, with a part of the gas barrier film cut away. FIG. 3 is a schematic cross-sectional view showing only a unit cell that constitutes an assembled battery, which is a component of the battery module of the first embodiment. FIG. 4 is a schematic perspective view showing a partially cutaway unit cell provided with a light-emitting portion. FIG. 5 is a schematic perspective view showing an enlarged view of only the light emitting portion. FIG. 6 is a schematic cross-sectional view showing how light guide tubes are arranged in a structure.

As shown in FIGS. 1 and 2, the battery module of this embodiment includes an assembled battery 11, a plurality of light emitting units 12, a gas barrier film 13, a light guide tube 14, a light receiving unit 15, and a battery state analyzer 16. configured as follows. The assembled battery 11 and the plurality of light emitting units 12 are covered and sealed with a gas barrier film 13 , and the structure including the gas barrier film 13 is called a structure 10 .

(Battery pack)
The assembled battery 11 is formed by stacking a plurality of unit cells 21 of lithium ion secondary batteries (five layers in the examples of FIGS. 2 and 6). Here, for example, the unit cells 21 adjacent in the stacking direction are stacked such that the upper surface of the negative electrode current collector and the lower surface of the positive electrode current collector are adjacent to each other, and the

lead wires

22 and 23 are in contact with the uppermost surface and the lowermost surface. Each unit cell 21 is connected in series. The assembled battery 11 in this embodiment includes a plurality of individual cells 21 stacked and connected in series as described above. It also includes those in which multiple layers are laminated so as to contact with. Moreover, the current collector of the unit cell 21 can also be used as a resin current collector for a bipolar electrode in which a positive electrode is formed on one surface of the current collector and a negative electrode is formed on the other surface of the current collector. Therefore, in the assembled battery 11 of the present embodiment, a positive electrode is formed on one surface of a current collector (bipolar electrode resin current collector) and a negative electrode is formed on the other surface to form a bipolar electrode, It includes a laminate (bipolar battery) in which a bipolar electrode is laminated with a separator.

(cell)
A single-layer cell 21, which is a component of the assembled battery 11, is shown in FIG. In the unit cell 21, a positive electrode 24 and a negative electrode 26 are laminated with a separator 25 interposed therebetween, and a sealing portion 27 is provided to surround and seal the outer peripheral portions of the positive electrode 24, the separator 25, and the negative electrode 26, and is sealed. An electrolytic solution is enclosed in the inside. The positive electrode 24 is formed by stacking a positive current collector 31 and a positive electrode active material layer 32 . The negative electrode 26 is formed by stacking a negative electrode current collector 33 and a negative electrode active material layer 34 . The assembled battery 11 preferably has flexibility. For example, excellent flexibility can be obtained by using a resin current collector as the current collector.

(Positive electrode current collector)
Materials constituting the positive electrode current collector 31 include metallic materials such as copper, aluminum, titanium, stainless steel, steel, nickel, and alloys thereof, baked carbon, conductive polymer materials, conductive glass, and the like. .

In addition, the current collector is preferably a resin current collector made of a conductive polymer material. The shape of the current collector is not particularly limited, and may be a sheet-like current collector made of the above material or a deposited layer made of fine particles made of the above material. Although the thickness of the current collector is not particularly limited, it is preferably 50 μm to 500 μm.

As the conductive polymer material that constitutes the resin current collector, for example, a conductive polymer or a resin to which a conductive agent is added as necessary can be used. As the conductive agent that constitutes the conductive polymer material, the same conductive aid as that contained in the above-described coated positive electrode active material can be preferably used.

The positive electrode current collector 31 preferably contains a conductive filler and a matrix resin. Examples of matrix resins include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyethernitrile (PEN), polytetrafluoroethylene (PTFE ), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resins, silicone resins or mixtures thereof. From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferred, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferred. (PMP).

The conductive filler is selected from materials having electrical conductivity.
Specifically, metal [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), etc. ], and mixtures thereof, but are not limited thereto. These conductive fillers may be used singly or in combination of two or more. Also, alloys or metal oxides thereof may be used. From the viewpoint of electrical stability, preferred are aluminum, stainless steel, carbon, silver, copper, titanium and mixtures thereof, more preferred are silver, aluminum, stainless steel and carbon, and still more preferred is carbon. These conductive fillers may be those obtained by coating a conductive material (a metal material among the conductive filler materials described above) around a particulate ceramic material or a resin material by plating or the like.

The average particle size of the conductive filler is not particularly limited, but from the viewpoint of the electrical characteristics of the battery, it is preferably 0.01 μm to 10 μm, more preferably 0.02 μm to 5 μm. More preferably, it is between 0.03 μm and 1 μm. In this specification, the "particle diameter" means the maximum distance L among the distances between any two points on the outline of the particle. The value of "average particle size" is the average value of the particle size of particles observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.

The shape (form) of the conductive filler is not limited to a particle form, and may be in a form other than the particle form. good.

The conductive filler may be a conductive fiber having a fibrous shape. Examples of conductive fibers include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers obtained by uniformly dispersing highly conductive metals and graphite in synthetic fibers, and metals such as stainless steel. Examples include fibrillated metal fibers, conductive fibers obtained by coating the surface of organic fibers with metal, and conductive fibers obtained by coating the surfaces of organic fibers with a resin containing a conductive substance. Among these conductive fibers, carbon fibers are preferred. A polypropylene resin in which graphene is kneaded is also preferable. When the conductive filler is conductive fiber, the average fiber diameter is preferably 0.1 μm to 20 μm.

The weight ratio of the conductive filler in the resin current collector is preferably 5% to 90% by weight, more preferably 20% to 80% by weight. In particular, when the conductive filler is carbon, the weight ratio of the conductive filler is preferably 20% by weight to 30% by weight.

The resin current collector may contain other components (dispersant, cross-linking accelerator, cross-linking agent, colorant, ultraviolet absorber, plasticizer, etc.) in addition to the matrix resin and the conductive filler. Moreover, a plurality of resin current collectors may be laminated and used, or a resin current collector and a metal foil may be laminated and used.

Although the thickness of the positive electrode current collector 31 is not particularly limited, it is preferably 5 μm to 150 μm. When a plurality of resin current collectors are laminated and used as a positive electrode current collector, the total thickness after lamination is preferably 5 μm to 150 μm.

The positive electrode current collector 31 can be obtained, for example, by molding a conductive resin composition obtained by melt-kneading a matrix resin, a conductive filler, and a filler dispersing agent to be used as necessary into a film by a known method. can. Methods for forming the conductive resin composition into a film include, for example, known film forming methods such as a T-die method, an inflation method and a calender method. The positive electrode current collector 31 can also be obtained by a molding method other than film molding.

(Positive electrode active material layer)
The positive electrode active material layer 32 is preferably a non-bound mixture containing a positive electrode active material. Here, the non-bound body means that the position of the positive electrode active material is not fixed in the positive electrode active material layer, and the positive electrode active materials and the positive electrode active materials and the positive electrode active material and the current collector are irreversibly means not fixed.

When the positive electrode active material layer 32 is a non-bound body, the positive electrode active materials are not irreversibly fixed to each other, and therefore can be separated without mechanically destroying the interface between the positive electrode active materials. Even when stress is applied to the material layer 32, the positive electrode active material moves, which is preferable because the positive electrode active material layer 22 can be prevented from being broken. The positive electrode active material layer 32, which is a non-binder, can be obtained by a method such as forming a positive electrode active material layer containing a positive electrode active material and an electrolytic solution but not containing a binder.

In this specification, the binder means an agent that cannot reversibly fix the positive electrode active materials together and the positive electrode active material and the current collector, and includes starch, polyvinylidene fluoride, polyvinyl alcohol, carboxyl Known solvent-drying type binders for lithium ion batteries such as methylcellulose, polyvinylpyrrolidone, tetrafluoroethylene, styrene-butadiene rubber, polyethylene and polypropylene can be used. These binders are used by dissolving or dispersing them in a solvent, and by volatilizing and distilling off the solvent, the surface solidifies without exhibiting adhesiveness, so that the positive electrode active materials and the positive electrode active material and the current collector are solidified. cannot be reversibly fixed.

Examples of positive electrode active materials include composite oxides of lithium and transition metals (composite oxides containing one type of transition metal (LiCoO ₂ , LiNiO ₂ , LiAlMnO ₄ , LiMnO ₂ and LiMn ₂ O ₄ , etc.), transition metal elements Two kinds of composite oxides (for example, LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _1/3 Co _1/3 Al _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂ ) and a composite oxide containing three or more metal elements [for example, LiM _a M′ _b M″ _c O ₂ (M, M′ and M″ are different transition metal elements, , satisfying a+b+c=1, such as LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), etc.], lithium-containing transition metal phosphates (e.g., LiFePO ₄ , LiCoPO ₄ , LiMnPO ₄ and LiNiPO ₄ ), Transition metal oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS ₂ ) and conductive polymers (eg polyaniline, polypyrrole, polythiophene, polyacetylene and poly-p-phenylene and polyvinylcarbazole ) and the like, and two or more of them may be used in combination. Note that the lithium-containing transition metal phosphate may have a transition metal site partially substituted with another transition metal.

The volume average particle size of the positive electrode active material is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 35 μm, even more preferably 2 μm to 30 μm, from the viewpoint of the electrical characteristics of the battery. .

The positive electrode active material may be a coated positive electrode active material in which at least part of the surface is coated with a coating material containing a polymer compound. When the positive electrode active material is covered with the coating material, the volume change of the positive electrode is moderated, and the expansion of the positive electrode can be suppressed.

As the polymer compound constituting the coating material, those described as active material coating resins in JP-A-2017-054703 and WO-2015-005117 can be suitably used.

The covering material may contain a conductive agent. As the conductive agent, the same conductive filler contained in the positive electrode current collector 21 can be preferably used.

The positive electrode active material layer 32 may contain an adhesive resin. As the adhesive resin, for example, a non-aqueous secondary battery active material coating resin described in JP-A-2017-054703 is mixed with a small amount of an organic solvent to adjust its glass transition temperature to room temperature or lower. Also, those described as adhesives in JP-A-10-255805 can be preferably used. In addition, adhesive resin is a resin that does not solidify even if the solvent component is volatilized and dried, and has adhesiveness (the property of adhering by applying a slight pressure without using water, solvent, heat, etc.) means On the other hand, a solution-drying type electrode binder used as a binding agent is one that evaporates a solvent component to dry and solidify, thereby firmly adhering and fixing active materials to each other. Therefore, the binder (solution-drying type electrode binder) and the tacky resin are different materials.

The positive electrode active material layer 32 may contain an electrolytic solution containing an electrolyte and a non-aqueous solvent. _As _the electrolyte _, _those used in known electrolytic solutions _can _be used _. lithium salts of _organic acids such as LiN ₍ _CF3SO2 ₎ ₂ , LiN( _C2F5SO2 ₎ ₂ and LiC( _CF3SO2 ₎ ₃ _; ) is preferred.

As the non-aqueous solvent, those used in known electrolytic solutions can be used. compounds, amide compounds, sulfones, sulfolane, etc. and mixtures thereof can be used.

Examples of lactone compounds include 5-membered ring (γ-butyrolactone, γ-valerolactone, etc.) and 6-membered ring lactone compounds (δ-valerolactone, etc.).

　Cyclic carbonates include propylene carbonate, ethylene carbonate and butylene carbonate. Chain carbonates include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate and di-n-propyl carbonate.

Examples of chain carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate and methyl propionate. Cyclic ethers include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane and 1,4-dioxane. Chain ethers include dimethoxymethane and 1,2-dimethoxyethane.

Phosphate esters include trimethyl phosphate, triethyl phosphate, ethyldimethyl phosphate, diethylmethyl phosphate, tripropyl phosphate, tributyl phosphate, tri(trifluoromethyl) phosphate, tri(trichloromethyl) phosphate, Tri(trifluoroethyl) phosphate, tri(triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphospholan-2-one, 2-trifluoroethoxy-1,3,2- dioxaphospholan-2-one, 2-methoxyethoxy-1,3,2-dioxaphospholan-2-one and the like. Acetonitrile etc. are mentioned as a nitrile compound. DMF etc. are mentioned as an amide compound. Sulfones include dimethylsulfone, diethylsulfone, and the like. The non-aqueous solvent may be used singly or in combination of two or more.

Among non-aqueous solvents, preferred from the viewpoint of battery output and charge-discharge cycle characteristics are lactone compounds, cyclic carbonates, chain carbonates and phosphates, and more preferred are lactone compounds, cyclic carbonates and chains. carbonic acid ester, and particularly preferred is a mixture of cyclic carbonic acid ester and chain carbonic acid ester. Most preferred is a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) or a mixture of ethylene carbonate (EC) and propylene carbonate (PC).

The positive electrode active material layer 32 may contain a conductive aid. As the conductive aid, a conductive material similar to the conductive filler contained in the positive electrode current collector 21 can be suitably used.

The weight ratio of the conductive aid in the positive electrode active material layer 32 is preferably 3% to 10% by weight.

The positive electrode active material layer 32 can be produced, for example, by applying a slurry containing a positive electrode active material and an electrolytic solution to the surface of the positive electrode current collector 31 or the substrate and removing excess electrolytic solution. When the cathode active material layer 22 is formed on the surface of the substrate, the cathode active material layer 32 may be combined with the cathode current collector 31 by a method such as transfer. The slurry may contain a conductive aid and an adhesive resin, if necessary. Also, the positive electrode active material may be a coated positive electrode active material.

Although the thickness of the positive electrode active material layer 32 is not particularly limited, it is preferably 150 μm to 600 μm, more preferably 200 μm to 450 μm, from the viewpoint of battery performance.

(Negative electrode current collector)
As the negative electrode current collector 33, one having the same structure as that described for the positive electrode current collector 31 can be appropriately selected and used, and can be obtained by the same method. Although the thickness of the negative electrode current collector 33 is not particularly limited, it is preferably 5 μm to 150 μm.

(Negative electrode active material layer)
The negative electrode active material layer 34 is preferably a non-bonded mixture containing a negative electrode active material. Reasons why the negative electrode active material layer is preferably a non-binder, and reasons why the positive electrode active material layer 32 is preferably a non-binder , and the method for obtaining the positive electrode active material layer 32 which is a non-binder.

Examples of negative electrode active materials include carbon-based materials [graphite, non-graphitizable carbon, amorphous carbon, baked resin bodies (for example, carbonized products obtained by baking phenolic resin and furan resin, etc.), cokes (for example, pitch coke, needle coke and petroleum coke, etc.) and carbon fiber, etc.], silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composites (carbon particles whose surface is coated with silicon and / or silicon carbide, silicon particles or oxide Silicon particles coated with carbon and/or silicon carbide, silicon carbide, etc.) and silicon alloys (silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon - manganese alloys, silicon-copper alloys and silicon-tin alloys, etc.)], conductive polymers (e.g., polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxides, etc.), metal alloys (eg, lithium-tin alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.), mixtures of these with carbonaceous materials, and the like. Of the negative electrode active materials described above, those that do not contain lithium or lithium ions inside may be pre-doped in advance to partially or wholly contain lithium or lithium ions.

Among these, carbon-based materials, silicon-based materials, and mixtures thereof are preferable from the viewpoint of battery capacity and the like. As the carbon-based material, graphite, non-graphitizable carbon, and amorphous carbon are more preferable, and as the silicon-based material, , silicon oxide and silicon-carbon composites are more preferred.

The volume average particle size of the negative electrode active material is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 20 μm, even more preferably 2 μm to 10 μm, from the viewpoint of the electrical characteristics of the battery.

In this specification, the volume average particle size of the negative electrode active material means the particle size (Dv50) at an integrated value of 50% in the particle size distribution determined by the microtrack method (laser diffraction/scattering method). The microtrack method is a method of obtaining a particle size distribution by utilizing scattered light obtained by irradiating particles with laser light. For the measurement of the volume average particle size, a Microtrac manufactured by Nikkiso Co., Ltd. or the like can be used.

The negative electrode active material may be a coated negative electrode active material in which at least part of the surface is coated with a coating material containing a polymer compound. When the periphery of the negative electrode active material is covered with the coating material, the volume change of the negative electrode is moderated, and the expansion of the negative electrode can be suppressed.

As the coating material, the same coating material as that constituting the coated positive electrode active material can be suitably used.

The negative electrode active material layer 34 contains an electrolytic solution containing an electrolyte and a non-aqueous solvent. As for the composition of the electrolytic solution, an electrolytic solution similar to the electrolytic solution contained in the positive electrode active material layer 32 can be suitably used.

The negative electrode active material layer 34 may contain a conductive aid. As the conductive aid, a conductive material similar to the conductive filler contained in the positive electrode active material layer 32 can be preferably used.

The weight ratio of the conductive aid in the negative electrode active material layer 34 is preferably 2% to 10% by weight.

The negative electrode active material layer 34 may contain an adhesive resin. As the adhesive resin, the same adhesive resin as an optional component of the positive electrode active material layer 32 can be preferably used.

The negative electrode active material layer 34 can be produced, for example, by applying a slurry containing a negative electrode active material and an electrolytic solution to the surface of the negative electrode current collector 33 or the substrate and removing excess electrolytic solution. When the negative electrode active material layer 34 is formed on the surface of the substrate, the negative electrode active material layer 34 may be combined with the negative electrode current collector 33 by a transfer method or the like. The slurry may contain a conductive aid, an adhesive resin, or the like, if necessary. Also, the negative electrode active material may be a coated negative electrode active material.

Although the thickness of the negative electrode active material layer 34 is not particularly limited, it is preferably 150 μm to 600 μm, more preferably 200 μm to 450 μm, from the viewpoint of battery performance.

(separator)
As the separator 25, a porous film made of polyethylene or polypropylene, a laminated film of the above porous films (laminated film of porous polyethylene film and porous polypropylene, etc.), synthetic fiber (polyester fiber, aramid fiber, etc.), or glass fiber and separators used in known lithium-ion cells, such as non-woven fabrics made of such materials, and those having ceramic fine particles such as silica, alumina, and titania adhered to their surfaces.

The unit cell 21 has a configuration in which an electrolytic solution is enclosed by sealing the outer peripheries of the positive electrode active material layer 32 and the negative electrode active material layer 34 . As a method of sealing the outer peripheries of the positive electrode active material layer 32 and the negative electrode active material layer 33, for example, a method of sealing using the sealing portion 27 can be given. The seal portion 27 is arranged between the positive electrode current collector 31 and the negative electrode current collector 33 and has a function of sealing the outer periphery of the separator 25 .

The material for the seal portion 27 is not particularly limited as long as it is a material that is durable against the electrolytic solution, but a polymer material is preferable, and a thermosetting polymer material is more preferable. Specifically, epoxy-based resins, polyolefin-based resins, polyurethane-based resins, polyvinylidene fluoride resins, and the like can be mentioned, and epoxy-based resins are preferred because of their high durability and ease of handling.

Further, the sealing portion 27 may be a frame made of a polymer material that is durable against the above-described electrolytic solution and having a through hole for accommodating the positive electrode active material layer 32 or the negative electrode active material layer 34 . When the sealing portion 27 is a frame, the positive electrode current collector 31 or the negative electrode current collector 33 is bonded to one frame surface of the frame to seal one end of the through hole, and the other frame of the frame is sealed. The unit cell 21 can be obtained by a method of bonding and sealing the frames with the separator inserted on the surface.

Although an example of the configuration of the cell 21 has been described above, the cell 21 according to this embodiment is not limited to the illustrated example. For example, the unit cell 21 in this embodiment includes a battery using a liquid material for the electrolyte and a battery using a solid material for the electrolyte (so-called all-solid battery). In addition, the unit cell in the present embodiment includes a battery having a metal foil (metal current collector foil) as a current collector, and is composed of a resin to which a conductive material is added instead of the metal foil, a so-called resin current collector. including batteries with When the resin current collector is used as a resin current collector for a bipolar electrode as described above, a positive electrode is formed on one surface of the resin current collector and a negative electrode is formed on the other surface to form a bipolar electrode. A model electrode may also be used. Note that the unit cell in the present embodiment includes those in which the positive electrode or negative electrode active material or the like is applied to the positive electrode current collector or the negative electrode current collector using a binder to form an electrode, and in the case of a bipolar battery, A bipolar electrode having a positive electrode layer is formed by applying a positive electrode active material or the like using a binder to one surface of the current collector, and a negative electrode layer is formed by applying a negative electrode active material or the like to the opposite surface using a binder. Including configured.

(Light-emitting part)
As shown in FIGS. 2 and 4, on the side surface of the assembled battery 11, light-emitting units 12 for transmitting optical signals based on the state of each unit cell 21 constituting the assembled battery 11 are arranged. is provided.

As shown in FIG. 5 , the light emitting section 12 includes a wiring board 41 having wiring inside or on the surface thereof, a light emitting element 42 mounted on the wiring board 41 , and two control elements 43 .

Measurement terminals

44 a and 44 b are provided at the ends of the wiring board 41 . The

measurement terminals

44a and 44b are provided at positions where one measurement terminal contacts the positive electrode current collector and the other measurement terminal contacts the negative electrode current collector when connected to the cell 12 . In this case, the

measurement terminals

44 a and 44 b are voltage measurement terminals for measuring the voltage between the positive electrode current collector and the negative electrode current collector of the cell 12 .
A measurement terminal (not shown) is also provided on the surface of the wiring board 41 that faces the back side of the light emitting element 42 . This measurement terminal (not shown) can be used as a temperature measurement terminal for measuring the temperature of the cell 12 .

The light emitting unit 12 measures the characteristics of the cell 21 and emits an optical signal according to the characteristics. The

measurement terminals

44 a and 44 b and a temperature measurement terminal (not shown) are electrically connected to the control element 43 , and the control element 43 is electrically connected to the light emitting element 42 . The control element 43 controls the light emitting element 42 to emit light according to a predetermined optical signal pattern based on the information indicating the characteristics of the cell 21 measured by the

measuring terminals

44a and 44b. The information measured by the

measurement terminals

44a and 44b is preferably the voltage and temperature of the cell 12. FIG. The light emitting element 42 emits light according to a predetermined optical signal pattern based on the control signal generated by the control element 43 to generate an optical signal.

A rigid substrate or a flexible substrate can be used as the wiring substrate 41 constituting the light emitting section 12 . When the wiring substrate is shaped as shown in FIG. 5, it is preferable to use a flexible substrate. As the control element 43, any semiconductor element such as IC, LSI, etc. can be used. Although FIG. X shows an example in which two control elements are mounted, the number of control elements is not limited, and may be one or three or more.

As the light-emitting element 42, an element capable of converting an electric signal into an optical signal, such as an LED element or an organic EL element, can be used, and the LED element is preferable. For example, light emitting element 42 may be one or more of a light emitting element having a center wavelength of 700 nm to 800 nm, a light emitting element having a center wavelength of 850 nm to 950 nm, or a light emitting element having a center wavelength of 1000 nm to 1400 nm. A light emitting element with a center wavelength of 700 nm to 800 nm and a light emitting element with a center wavelength of 850 nm to 950 nm may be combined to form the light emitting section 12, or a light emitting element with a center wavelength of 850 nm to 950 nm and a light emitting element with a center wavelength of 1000 nm to 1400 nm. The light-emitting element 12 may be configured by combining the light-emitting elements of In the present embodiment, a case is exemplified in which the light emitting unit 12 that emits signal light with a center wavelength within the range of visible light, for example, a center wavelength of 700 nm to 800 nm, is used as an optical signal.
It should be noted that it is not essential that the light-emitting section 12 has a wiring board, and the light-emitting section 12 may be configured by connecting the control element and the light-emitting element without using the wiring board.

It is preferable that the light emitting unit 12 is electrically connected to the negative electrode current collector and the positive electrode current collector of the cell 21 so as to be able to receive power supply from the assembled battery 21 . When the light emitting part 12 is electrically connected to the negative electrode current collector and the positive electrode current collector, the light emitting element 42 can emit light by receiving power supply from the assembled battery 11 . Since it is not necessary to provide a power source and wiring for causing the light emitting element 42 to emit light, the configuration can be simplified.
Although electrodes for receiving power supply are not shown in FIG. 5, it is preferable to provide electrodes other than the measurement terminals in the light emitting section.

Further, when the light-emitting portion 12 is electrically connected to the negative electrode current collector and the positive electrode current collector, the negative electrode current collector and the positive electrode current collector are resin current collectors, and the negative electrode current collector and the positive electrode current collector are is preferably directly coupled and electrically connected to the electrode of the light-emitting portion. When using a resin current collector, the resin current collector and the electrode of the light emitting part 12 are brought into contact with each other, and the resin current collector is heated to soften the resin, thereby directly bonding the resin current collector and the electrode of the light emitting part. can be made Also, electrical connection can be made by interposing another conductive bonding material such as solder between the current collector and the light emitting section 12 .

(Gas barrier film)
As shown in FIGS. 1 and 2, the assembled battery 11 and the plurality of light emitting units 12 are housed while being covered with a gas barrier film 13 that is an exterior body. The gas barrier film 13 seals the assembled battery 11 and the plurality of light-emitting portions 12 in a state in which the tip portions of the lead-out

terminals

22 and 23 of the assembled battery 11 are pulled out to the outside. The gas barrier film 13 has a function of preventing permeation of various gases such as hydrogen gas generated from the electrodes of the assembled battery 11, etc. transparent. In the present embodiment, the optical signal of the light emitting element 42 has a center wavelength within the range of visible light, for example, 700 nm to 800 nm, so the gas barrier film 13 is transparent to the visible light. In the case of using the light emitting element 42 that emits light other than visible light, for example, an optical signal with a center wavelength of 850 nm to 950 nm in the range of infrared light, the gas barrier film 13 may be transparent to the infrared light. will use things.

The gas barrier film 13 is a member having a function of transmitting an optical signal emitted from the light emitting element 42 of the light emitting section 12. For example, a suitable material corresponding to visible light is a base film (PET (polyethylene terephthalate resin), nylon, etc.) on which inorganic deposition barrier layers and coating barrier layers such as alumina (Al ₂ O ₃ ) and silicon oxide (SiO _x ) are laminated, and silicon oxide etc. on a base plastic film. Vacuum vapor deposition etc. are mentioned.

In this embodiment, the gas barrier film 13 is transparent to the optical signal emitted from the light emitting element 42 of the light emitting section 12 and has the function of transmitting the optical signal. Therefore, an optical signal emitted from the light emitting element 42 covered with the gas barrier film 13 can be received outside the structure 10 via the gas barrier film 13 . Therefore, as shown in FIG. 6, the battery module of the present embodiment may have a configuration in which the gas barrier film 13 covers the plurality of light-emitting portions 12 provided on the side surface of the assembled battery 11 in direct proximity to or in contact with them. In the structure 10, between the light-emitting element 42 of the light-emitting portion 12 and the gas barrier film 13, an optical component or the like for transmitting an optical signal indicating the state of the unit cell 21 constituting the assembled battery 12 to the outside is arranged. It is not necessary to draw out a part of the external body from the exterior body. Since optical components are easily damaged, in a configuration in which a part of the optical component is pulled out of the gas barrier film 13, a large pressure cannot be applied to the optical component when sealing with the gas barrier film 13, resulting in incomplete sealing. There is concern that In the present embodiment, such an optical component may be arranged outside the gas barrier film 13 isolated from the structure 10, so that the internal configuration of the structure 10 (the configuration sealed with the gas barrier film 13) is greatly reduced. In addition, the assembled battery 11 can be reliably sealed by the gas barrier film 13, and a battery module in which weakening of the structure 10 is suppressed is realized.

(light guide tube)
The light guide tube 14 guides the optical signal generated by the light emitting element 42 of the light emitting section 12, and includes a plurality of light emitting sections 12 outside the structure 10 as shown in FIGS. It is provided in contact with or close to the surface of the gas barrier film 13 so as to cover the region through the gas barrier film 13 . The light guide tube 14 has a width sufficient to receive the optical signal from the light emitting element 42 of the light emitting section 12 (the length in the direction orthogonal to the stacking direction of the unit cells 21, or the light emitting element 42 in the unit cell 21). length in the direction along the provided edge). The width dimension of the light guide tube 14 is larger than the maximum dimension of the light emitting surface of the light emitting element 42 (the diameter if the light emitting surface is circular, and the diagonal if the light emitting surface is rectangular). The light guide tube 14 is arranged so as to cover the light-emitting surfaces of the plurality of light-emitting portions 12 (each corresponding to the plurality of stacked unit cells 21) (preferably to cover the entire light-emitting surface). The light guide tube 14 is arranged so as to cover all of the light emitting directions of the light emitting section 12 (including cases in which the direction is aligned with the vertical direction of the light emitting surface and cases in which the direction is inclined from the vertical direction of the light emitting surface).

The light guide tube 14 is made of a material with a higher refractive index than the surrounding medium (for example, air). Here, the high refractive index means a refractive index with a difference between the refractive index of the surrounding medium and a value that allows incident light to be confined in the light guide tube 14 and propagated. For example, the light guide tube 14 can be configured using a resin film or resin plate with a high refractive index. The resin that forms the resin film or the resin plate that constitutes the light guide tube 14 is not limited, but may be an acrylic resin or the like. For example, a flexible resin film or resin plate can be selected from among high-refractive-index resins called optical materials. A resin that forms the resin film or resin plate that constitutes the light guide tube 14 is preferably a material that does not easily absorb the emission wavelength band of the light emitting element 42 . In this embodiment, since the light emission wavelength band of the light emitting element 42 is visible light, it is desirable that the resin forming the resin film or resin plate should have a low absorption peak at 700 nm to 800 nm. If the emission wavelength band of the light emitting element 42 is infrared light, a material with a low absorption peak in the range of 850 nm to 950 nm is desirable.

In this embodiment, the gas barrier film 13 is transparent to the optical signal emitted from the light emitting element 42 of the light emitting section 12 and has the function of transmitting the optical signal. Therefore, the light guide tube 14 is arranged outside the gas barrier film 13 isolated from the structure 10, and the optical signal emitted from the light emitting element 42 covered with the gas barrier film 13 is guided through the gas barrier film 13. can be done. Since there is no need to dispose part of the light guide tube 14 inside the gas barrier film 13, the internal configuration of the structure 10 is greatly simplified, and the assembled battery 11 can be reliably sealed by the gas barrier film 13. be done.

(Light receiving section)
As shown in FIG. 1, the light receiving section 15 includes, outside the gas barrier film 13, a light receiving element 45 for receiving a plurality of optical signals propagating inside the light guide tube 14. The light receiving element 45 receives the optical signals. By inversely converting the electric signal into an electric signal, an electric signal indicating the state of the cells 21 included in the assembled battery 12 can be obtained. An LED element, a phototransistor, or the like can be used as the light receiving element 45, and an LED element is preferable. The light receiving section 15 may be one in which the light receiving element 45 is mounted on a wiring board, or the light receiving section 15 may be the light receiving element itself.

FIG. 7 is a block diagram schematically showing a circuit configuration including peripheral members of the battery module of this embodiment.
In FIG. 7, the gas barrier film 13 that seals the assembled battery 11 and the plurality of light-emitting portions 12 is indicated by broken lines. The light guide tube 14 is located outside the dotted line area, and is shown to be arranged outside the gas barrier film 13 . Lead

wires

22 and 23 are also led out of the gas barrier film 13 .

A light-receiving section 15 is connected to a light guide tube 14 provided outside the gas barrier film 13 , so that a light receiving element 45 of the light-receiving section 15 can receive an optical signal derived from one end of the light guide tube 14 . ing.
A battery state analyzer 16 is connected to the light receiving unit 15 , the battery state analyzer 16 analyzes the optical signal, and analyzes the characteristics of the cells 21 included in the assembled battery 11 .
The

lead wires

22 and 23 are connected to the device main body 100, and the device operates in the device main body 100 using the assembled battery 11 as a power source.

Next, with reference to FIGS. 8A to 10C, optical signal patterns corresponding to the characteristics of the cell 21 will be described.
In order to obtain these optical signal patterns, the light emitting unit 12 has a voltage measuring terminal for measuring the voltage between the positive electrode current collector and the negative electrode current collector of the cell 21 and a temperature sensor for measuring the temperature of the cell 21 . A measurement terminal is provided, and a control element 43 is provided for controlling the light emitting element 42 to emit light in a predetermined optical signal pattern according to the voltage measured by the voltage measurement terminal and the temperature measured by the temperature measurement terminal. ing. The control element 43 controls the light emitting element 42 to emit light according to a predetermined optical signal pattern.

FIGS. 8A to 8E are schematic diagrams showing examples of optical signal patterns when the voltages of the cells 21 are different. 8A to 8E show optical signal patterns when the single cell voltage is 4 V to 4.5 V, 3.5 V to 4 V, 3 V to 3.5 V, 2.5 V to 3 V, and 2 V to 2.5 V, respectively. there is These patterns are pulse patterns in which the ON/OFF of the optical signal is repeated within a predetermined period of time, and the predetermined period of time is 100 seconds. The predetermined time is not particularly limited, and can be any time.

In these examples, the duration of one light emission is the same, and the higher the voltage, the greater the number of repetitions of light emission ON/OFF. Any optical signal pattern may be used. For example, the optical signal pattern may be such that the number of times of light emission ON/OFF is the same and the higher the voltage, the longer the time for one light emission. Moreover, it is not necessary that the duration of one light emission within a predetermined period of time is the same. Also, although the shape of the optical signal pattern is made to differ in voltage increments of 0.5 V, the voltage increment width is not particularly limited.

For example, unlike the mode shown in FIGS. 8A to 8E (the light emission time is the same, and the higher the voltage, the higher the number of repetitions of light emission ON/OFF), unlike the light signal pattern shown in FIG. The time and the number of repetitions of ON/OFF of light emission may be varied for each predetermined voltage. In the example shown in FIG. 9, the light emission time (W ₂ ) at the voltage of 3 V is set shorter than the light emission time (2W ₁ ) at the voltage of 4 V, and the light emission ON/OFF at the voltage of 3 V is repeated. The optical signal pattern is such that the number of repetitions of light emission ON/OFF is smaller than that at a voltage of 4V. Note that the time for one light emission at a voltage of 3 V may be different from the time for one light emission at a voltage of 4 V (W ₂ ≠W ₁ )). Further, each light emission time (W ₃ ) at the voltage of 2V is made shorter than each light emission time (W ₂ ) at the voltage of 3V, and light emission is ON/ON at the voltage of 2V. The optical signal pattern is such that the number of OFF repetitions is greater than when the voltage is 3V.

In this embodiment, light guide 14 is fed with light signals from all light emitting elements 42 (five light emitting elements 42 in this embodiment), and light guide 14 provides a common light path for these light signals. do. Therefore, transmission in the light guide tube 14 may occur in a crossed state. As shown in FIGS. 8A to 8E, if the same optical signal pattern is used for one light emission time, the transmission is likely to occur in a crossed state in the light guide tube 14. However, as shown in FIG. , for each predetermined voltage range), by setting a different light emission time and a different number of repetitions of light emission ON/OFF, crosstalk can be suppressed compared to the embodiments of FIGS. 8A to 8E. However, it is possible to easily determine which voltage (or which voltage range) a specific optical signal corresponds to from a plurality of mixed optical signals.

FIG. 8F is a schematic diagram showing an example of an optical signal pattern when the temperature of the cell 21 is equal to or higher than a predetermined temperature. When the temperature of the cell 21 is equal to or higher than a predetermined temperature, it is determined that a failure mode of temperature abnormality has occurred, and an optical signal pattern of "temperature abnormality" as shown in FIG. 8F is generated regardless of the voltage of the cell 21. make it If the temperature of the cell 21 is less than the predetermined temperature, the temperature measured by the temperature measurement terminal is not reflected in the optical signal pattern.

10A to 10C are schematic diagrams showing examples of optical signal patterns derived from optical waveguides.
In FIG. 10A, all the optical signal patterns divided every 100 seconds are optical signal patterns corresponding to voltages of 3V to 3.5V, and the voltages of all the cells 21 are within the range of 3V to 3.5V. It turns out that
In FIG. 10B, the optical signal patterns divided every 100 seconds include one optical signal pattern corresponding to a voltage of 2V to 2.5V, three optical signal patterns corresponding to a voltage of 3V to 3.5V, and voltages of 4V to 4.5V. There is one optical signal pattern corresponding to 5V, and it can be seen that the voltage varies among the cells 21 . A cell 21 with too low voltage may be short-circuited, and a cell 21 with too high voltage may be overcharged.
In FIG. 10C, the optical signal patterns divided every 100 seconds include four optical signal patterns corresponding to voltages of 3 V to 3.5 V and one optical signal pattern corresponding to abnormal temperature. It can be seen that a temperature anomaly has occurred.
Since thermal runaway may have started in the unit cell 21 in which the temperature abnormality has occurred, it is necessary to consider replacement.

It can be seen from the optical signal patterns shown in FIGS. 10B and 10C that some of the five cells 21 may be malfunctioning. The state (voltage and temperature) of the cell 21 is constantly monitored, and when an optical signal pattern corresponding to a cell 21 with a sudden drop or rise in voltage is observed, the cell 21 with an abnormal temperature If the corresponding optical signal pattern is seen, it can be determined that the state inside the assembled battery 11 is defective.

The light receiving unit 15 receives such an optical signal pattern, converts it into an electric signal (pulse signal), reads the electric signal in the battery state analyzer, and obtains information on the voltage or temperature of the cell 21 . As a result, information about the total number of cells 21 with a certain voltage in the assembled battery 11 and information about the total number of cells 21 with abnormal temperature are obtained.

In the analysis of such optical signal patterns, by changing the optical signal pattern corresponding to the characteristics (voltage, temperature, etc.) of the single cell 21 for each single cell 21, which single cell 21 corresponds to which optical signal pattern. It is possible to judge whether Then, it is possible to confirm the presence of the defective cell 21 .

In addition, even if it is not possible to determine which unit cell 21 corresponds to which optical signal pattern, it is possible to confirm the existence of a defective unit cell 21, so there is no problem in discovering a defect in the assembled battery 11. can be applied without Moreover, since it is not necessary to provide the light receiving unit 15 and the battery state analyzer for processing the measurement information for each unit cell 21, the configuration can be simplified.

In addition, the interval at which information on the single battery 21 is obtained can also be arbitrarily set. FIGS. 10A to 10C show optical signal patterns of five 500 s regions of 100 s per unit cell 21 . Here, the pattern is shown without gaps every 100 seconds, but there may be an area without optical signal pattern information between the optical signal pattern of one cell 21 and the optical signal pattern of another cell 21 . In addition, it is examined what kind of optical signal pattern is obtained in a time longer than the predetermined time of the pulse pattern per unit cell 21 multiplied by the number of stacks of the unit cells 21. can recognize the state of each cell 21 included in (the total number of cells 21 of what V in the assembled battery 11, and the total number of cells 21 with abnormal temperature) .

As described above, according to this embodiment, the gas barrier film 13 is transparent to the optical signal emitted from the light emitting element 42 of the light emitting section 12 and has the function of transmitting the optical signal. Therefore, by providing the gas barrier film 13 so as to directly cover the light emitting element 42 of the light emitting section 12 , the optical signal from the light emitting element 42 can be externally received via the gas barrier film 13 . As described above, in the present embodiment, it is not necessary to provide optical components other than the light emitting unit 12 inside the structure 10 (the inside sealed with the gas barrier film 13), and some of the optical components and the like are replaced by the gas barrier film 13. Since there is no need to pull out to the outside, the internal configuration is greatly simplified, and the assembled battery 11 is reliably sealed by the gas barrier film 13, and a battery module that suppresses the weakening of the structure 10 is realized. .

[Method for manufacturing battery module]
FIG. 11 is a schematic perspective view showing how the battery module of the first embodiment is manufactured using a deep drawing vacuum packaging machine.
This deep-drawing vacuum packaging machine seals the assembled battery according to the battery module of the present embodiment with a gas barrier film to produce a structure.

The deep-drawing vacuum packaging machine inserts the above-described assembled battery 11 between the first gas barrier film 101 as the main film and the second gas barrier film 102 as the sealing film, and then removes the air inside while removing both films 101. , 102 are stuck together. Of the first gas barrier film 101 and the second gas barrier film 102, at least the first gas barrier film 101 is a strip-shaped transparent film having the same configuration as the gas barrier film 13 described above. In this embodiment, both

films

101 and 102 are strip-shaped transparent films having the same configuration as the gas barrier film 13 .

The first gas barrier film 101 and the second gas barrier film 102 are rolled around

mandrels

110a and 110b and incorporated into a deep drawing vacuum packaging machine. The mandrel 110a around which the first gas barrier film 101 is wound is arranged below the end of the apparatus, and the first gas barrier film 101 pulled out therefrom comes into contact with the upper guide roller 115, and the tip of the first gas barrier film 101 moves in the direction of the arrow A. move on.

The molding unit 111 includes a suction box 111a above and below the first gas barrier film 101, a heater 111b, and an elevation cylinder (not shown) for displacing the suction box 111a in the vertical direction of arrow B. The forming part 111 sequentially forms a plurality of concave portions 101a on the surface of the first gas barrier film 101 moving in the horizontal direction of arrow A. As shown in FIG. Here, a plurality of recesses 101 a are formed in two rows along the longitudinal direction of the first gas barrier film 101 . Each concave portion 101a is a space for accommodating the sealed object 103 (the assembled battery 11 and each unit cell 21 having the light-emitting portion 12 disposed therein) according to the present embodiment. A size and depth suitable for the battery 11 are ensured.

After the first gas barrier film 101 passes through the forming part 111 and the concave portions 101a are formed on the surface, the objects to be sealed 103 are successively inserted into the concave portions 101a manually or by a predetermined supply device. Here, in the two recesses 101a aligned in the width direction of the first gas barrier film 101, when the two objects to be sealed 103 are respectively fitted into the recesses 101a, the leading end portions of the

lead wires

22 and 23 of the assembled battery 11 are placed in the first direction. 1 project from both ends of the gas barrier film 101 .

Subsequently, the upper surface of the first gas barrier film 101 is covered with the second gas barrier film 102 . At this time, at one end of the overlapping portion of the first gas barrier film 101 and the second gas barrier film 102 in each recess 101a, the leading end portions of the

lead wires

22 and 23 of the assembled battery 11 protrude to the outside. The mandrel 110b around which the second gas barrier film 102 is wound is placed above the apparatus, and the second gas barrier film 102 pulled out therefrom passes through two

guide rollers

116 and 117, and the upper surface of the first gas barrier film 101 to reach

The first gas barrier film 101 and the second gas barrier film 102 have the same width. Further, in an actual apparatus, a drive mechanism using a chain or the like is provided in order to send out both

films

101 and 102 at a specified timing and by a specified length.

After the first gas barrier film 101 and the second gas barrier film 102 contact each other, they reach the sealing portion 112 . The sealing part 112 seals the first gas barrier film 101 and the second gas barrier film 102 while degassing, and seals the object 103 to be sealed.

12A and 12B are schematic cross-sectional views showing the configuration of the sealing portion 112 of the deep drawing vacuum packaging machine, where FIG. 12A is a cross-sectional view along the longitudinal direction of the first gas barrier film 101, and FIG. 12B is the first gas barrier film. 3 is a cross-sectional view along the width direction of the film 101. FIG.
The sealing portion 112 is composed of a movable box 112a below both

films

101 and 102 and a fixed box 112b above them. When the concave portion 101a containing the object 103 to be sealed reaches the fixed position of the sealing portion 112, the movable box 112a is lifted by the lifting cylinder, and both the

films

101 and 102 are sandwiched between the movable box 112a and the fixed box 112b. At that time, the inside is made to have a negative pressure, and air is removed from the concave portion 101a. At the same time, both the

films

101 and 102 are locally heated by the sealing portion 112c, and the

films

101 and 102 are adhered so as to surround the concave portion 101a, thereby sealing the object 103 to be sealed. After that, the movable box 112a is lowered to release both the films 101 and 102.例文帳に追加

Subsequently, both the

films

101 and 102 that have passed through the sealing portion 112 are cut by the vertical cutter 113 and the horizontal cutter 114 for each sealed object 103, and the

cut film

101 and 102 are covered with the gas barrier film 13. The structure 10 according to this embodiment is formed by sealing the sealing body 103 . The horizontal cutter 114 extends in the width direction of both

films

101 and 102 and is displaced in the vertical direction by an elevating cylinder. Therefore, when the recessed portion 101a is at a predetermined position, the

films

101 and 102 are cut in the width direction when the elevating cylinder is temporarily raised. Next, when the side portions of both

films

101 and 102 are cut by a disk-shaped vertical cutter 113, the concave portions 101a are individually cut out, and the individual structures 10 are formed.

Then, as shown in FIG. 13 , the light guide tube 14 is arranged so as to cover the area where the plurality of light emitting parts 12 on the surface of the gas barrier film 13 of the formed structure 10 can be seen through the gas barrier film 13 . After that, by attaching the light receiving portion 15 to the light guide tube 14, the battery module of the present embodiment is completed.

Here, the configuration and function of the molding section 111 will be described in detail.
The forming part 111 that forms the concave portion 101a in the first gas barrier film 101 is composed of a suction box 111a, a heater 111b, and the like. It's becoming The upper portion of the side walls surrounding the opening is a horizontally finished support surface. A vacuum pump is used to create a negative pressure in the suction box 111a, and both are connected by a pipe serving as an air flow path. Then, the suction box 111a is assembled with the mold with the lower packing interposed therebetween, and the upper packing is placed on the mold.

The mold is used to form the concave portion 101a in the first gas barrier film 101, and has a structure in which a sheet metal is finished into a predetermined shape by bending or welding. The outside of the upper edge of the frame is a frame plate that unfolds horizontally. The bottom plate and the side plate function as a mold for transferring the concave portion 101a to the first gas barrier film 101, and the first gas barrier film 101 is brought into close contact with the inner peripheral surface thereof. Therefore, the bottom plate and the side plate are provided with a plurality of ventilation holes for sucking air, and when the inside of the suction box 111a becomes a negative pressure, the first gas barrier film 101 is sucked and closely attached.

The frame plate is for placing the mold on the suction box 111a, and the outer edge of the frame plate rests on the support surface. Furthermore, the frame plate also serves to close the opening in order to maintain the negative pressure inside the suction box 111a. Therefore, it is not necessary to provide holes for air passages in the frame plate.

In the present embodiment, the band-shaped film in which the recessed portion 101a for housing the sealed object 103 is formed is, for example, a transparent film in which alumina (Al ₂ O ₃ ) or silicon oxide (SiO _x ) is vapor-deposited on a PET film. A first gas barrier film 101 is used. With laminated films such as aluminum, which were conventionally used as gas barrier films, it was difficult to deep-draw to a sufficient depth to form recesses. By using the first gas barrier film 101, which is a film, deeper drawing becomes possible. This makes it possible to easily form the desired recesses 101a that match the size and depth of the object 103 to be sealed with high precision in the first gas barrier film 101 .

In the present embodiment, it is necessary to form the structure 10 in a state in which the tip portions of the lead-out

terminals

22 and 23 of the assembled battery 11 are pulled out of the gas barrier film 13 . The object 103 to be sealed is inserted in a state protruding from the outside of the , and the second gas barrier film 102 is overlapped on the first gas barrier film 101 to seal the object 103 to be sealed. As a result, the object to be sealed 103 can be reliably sealed with both

films

101 and 102 while projecting the tip portion from the overlapped portion of both

films

101 and 102 .

<Second embodiment>
Next, a second embodiment will be described. The same components as those of the battery module of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[Configuration of battery module]
14A is a schematic perspective view showing the configuration of the battery module of the second embodiment. FIG. FIG. 14B is a schematic perspective view showing an exploded light guide portion that is a component of the battery module of the second embodiment. FIG. 14C is a schematic perspective view showing how the light guide section 52 and the light receiving section are attached to the structure in the battery module of the second embodiment.

As shown in FIGS. 14A and 14C, the battery module 1 of the present embodiment includes an assembled battery 11, a plurality of light-emitting portions 12, a gas barrier film 13, a light-shielding film 51 on the gas barrier film 13, a light guide portion 52, and a light receiving portion 15. , and a battery state analyzer 16 . The assembled battery 11 and the plurality of light emitting units 12 are covered and sealed with the gas barrier film 13 , and the structure including the gas barrier film 13 and the light shielding film 51 is referred to as a structure 20 .

The assembled battery 11 and the plurality of light emitting units 12 are housed while being covered with a gas barrier film 13 that is an exterior body. A light shielding film 51 is formed on the surface of the gas barrier film 13 except for a window portion 51a which is a region including the arrangement positions of the light emitting elements 42 of the plurality of light emitting portions 12 . As the material (light shielding agent) of the light shielding film 51, for example, black ink containing carbon black, silver ink containing aluminum fine particles, or gray light shielding mixture of these inks and white ink containing titanium oxide is used. agent or the like can be used. In this embodiment, by providing the light shielding film 51 on the surface of the gas barrier film 13 excluding the window portion 51a, the influence of disturbance light on optical transmission is suppressed.

The window portion 51a, which is an area in which the light shielding film 51 is not formed, is formed in an area including the arrangement positions of the light emitting elements 42 of the plurality of light emitting sections 12, here a rectangular area. In the window portion 51a, the gas barrier film 13 is exposed, and an optical signal emitted from the light emitting element 42 of the light emitting portion 12 positioned within the region of the window portion 51a passes through the gas barrier film 13 transparent to the optical signal. permeate to the outside through

As shown in FIG. 14B, the light guide section 52 has a light guide tube 14 similar to that of the first embodiment, and light shielding fins 53 to which the light guide tube 14 is attached and which covers it. The light shielding fin 53 has a surface covered with a light shielding film similar to the light shielding film 51 . The light shielding fins 53 may be formed by double molding, for example.

As shown in FIGS. 14A and 14C, the light guide section 52 is arranged in the structure 20 so that the light guide tube 14 covers the window section 51a. The light guide tube 14 is provided outside the structure 20 in contact with or close to the surface of the gas barrier film 13 so as to cover the region including the plurality of light emitting units 12 via the gas barrier film 13 . By arranging the light guide portion 52 on the structure 20, the window 51a is completely shielded, and substantially the entire surface of the structure 20 is covered with the light shielding film.

The light guide portion 52 is provided with the light receiving portion 15 so that the light receiving element 45 is optically connected to the light guide tube 14 .
An optical signal emitted from the light-emitting element 42 of the light-emitting portion 12 passes through the window portion 51 a of the gas barrier film 13 , propagates through the light guide tube 14 , and is received by the light-receiving portion 15 .

In this embodiment, the surface of the gas barrier film 13 transparent to the optical signal is covered with the light shielding film 51 except for the window portion 51a, and the light guide portion 52 is arranged so as to cover the window portion 51a. Substantially the entire surface of the structure 20 is covered with a light shielding film. In this state, optical signals are transmitted and received through the gas barrier film 13 between the light emitting element 42 of the light emitting section 12 in the structure 20 and the light receiving section 15 in the light guide section 52 . According to the present embodiment, it is not necessary to dispose the light guide section inside the gas barrier film 13 or pull out part of it to the outside of the gas barrier film 13, so that the internal configuration of the battery module is greatly simplified. In addition, reliable sealing of the battery pack 11 by the gas barrier film 13 is obtained. Furthermore, by appropriately providing a light shielding film, it is possible to realize a battery module capable of performing efficient optical transmission while suppressing the influence of disturbance light on optical transmission as much as possible.

[Method for manufacturing battery module]
Also in this embodiment, similarly to the first embodiment, the deep drawing vacuum packaging machine shown in FIG. 11 is used to manufacture the battery module of this embodiment.

(Manufacturing method 1)
Manufacturing method 1 will be described with reference to FIG. 15A. In manufacturing method 1, a main film 201 is used in which the entire surface of the first gas barrier film 101, which is a strip-shaped transparent film, is coated with a light shielding film 51 by printing or the like. Similarly, the entire surface of the second gas barrier film 102 is coated with a light shielding film to form a sealing film. As the sealing film, it is conceivable to use the second gas barrier film 102 as it is without forming a light shielding film. Both films are used to form individual structures 20 on a deep draw vacuum packaging machine.

Subsequently, the window 51a is formed in the structure 20. Then, as shown in FIG. The window portion 51a is formed by scraping or dissolving a region of the light shielding film 51 formed on the outermost surface of the structure 20, which includes the arrangement positions of the plurality of light emitting elements 42, here, a rectangular region. be. The gas barrier film 13 is exposed at the window portion 51a.

Then, the light guide part 52 is arranged in the window part 51 a so that the window part 51 a of the formed structure 20 is covered with the light guide tube 14 . After that, the light receiving section 15 is attached to the light guide section 52 to complete the battery module of the present embodiment.

According to manufacturing method 1, after the structure 20 is assembled, part of the light shielding film 51 is removed to form the window 51a. Therefore, the window portion 51a can be accurately and easily formed at the desired position of each molded structure 20 .

(Manufacturing method 2)
Manufacturing method 2 will be described with reference to FIG. 15B. In manufacturing method 2, as in the first embodiment, individual structures 10 are formed by a deep draw vacuum packaging machine using a first gas barrier film 101 as a main film and a second gas barrier film 102 as a sealing film. to form

Subsequently, a light shielding film 51 is formed on the surface of the gas barrier film 13 that is the exterior body of the structure 10 . For example, a region including the arrangement positions of the plurality of light emitting elements 42 inside the gas barrier film 13, which is a window portion forming portion of the structure 10, here, a rectangular region, is masked with a mask member 81, and in this state, the structure The entire surface of 10 is coated by spraying paint, which is a light shielding agent, from a nozzle 82 . Thereby, the light shielding film 51 is formed. Although the light shielding film 51 is also formed on the rear surface portion of the structure 10, it is conceivable that it is not formed on the rear surface portion.

Then, by removing the mask member 61, a structure 20 having a window portion 51a, which is a portion where the light shielding film 51 is not formed, in a rectangular region including the arrangement positions of the plurality of light emitting elements 42 is formed. The gas barrier film 13 is exposed at the window portion 51a.

According to manufacturing method 2, the light shielding film 51 and the window 51a are formed after the structure 10 is assembled. Therefore, the window portion 51a can be accurately and easily formed at the desired position of each molded structure 20 .

(Manufacturing method 3)
Manufacturing method 3 will be described with reference to FIG. 15C. In manufacturing method 3, a main film 301 is used in which a light shielding film 51 is formed by printing or the like on the surface of the first gas barrier film 101, which is a strip-shaped transparent film. Here, on the surface of the first gas barrier film 101, a portion to be formed of the window portion 51a when the structure 20 is formed, that is, a portion to be formed located on the side surface of the concave portion 101a formed in the first gas barrier film 101 is formed. A main film 301 is formed by removing the light shielding film 51 . The entire surface of the second gas barrier film 102 is coated with a light shielding film to form a sealing film. As the sealing film, it is conceivable to use the second gas barrier film 102 as it is without forming a light shielding film. Both films are used to form individual structures 20 each having a window 51a by means of a deep drawing vacuum packaging machine.

According to manufacturing method 3, a plurality of windows 51a are formed in the state of the main film for forming the first gas barrier film, and the structure 20 is formed using this main film. Therefore, it is possible to inexpensively and easily mass-produce battery modules each including the individual structures 20 in which the window portions 51a are formed.

[Modification]
Various modifications of the second embodiment will be described below. The same components as those of the battery modules of the first embodiment and the second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Modification 1)
16A and 16B are partially cutaway perspective views showing the configuration of Modification 1 of the battery module of the second embodiment, and FIG. 16B shows a state in which the light receiving portion 53 is attached to the structure 30. FIG. In FIGS. 16A and 16B, illustration of the

lead wires

22 and 23 is omitted.

As shown in FIG. 16A, the battery module 1 of Modification 1 includes an assembled battery 11, a plurality of light emitting units 12, a gas barrier film 13, a light shielding film 51 on the gas barrier film 13, a plurality of light receiving units 54, and a battery state analyzer. 16. The assembled battery 11 and the plurality of light emitting units 12 are covered and sealed with the gas barrier film 13 , and the structure including the gas barrier film 13 and the light shielding film 51 is referred to as a structure 30 .

The assembled battery 11 and the plurality of light emitting units 12 are housed while being covered with a gas barrier film 13 that is an exterior body. A light shielding film 51 is formed on the surface of the gas barrier film 13 except for the openings 51b that are aligned with the light emitting elements 42 of the plurality of light emitting units 12 . Each opening 51b, which is a region in which the light shielding film 51 is not formed, is formed to have substantially the same size and shape as the size and shape of each light emitting element 42 (here, circular shape, for example). At each opening 51b, the gas barrier film 13 is exposed, and an optical signal emitted from the light emitting element 42 of the light emitting unit 12 aligned with each opening 51b passes through the gas barrier film 13 transparent to the optical signal. permeate to the outside.

In Modified Example 1, each opening 51b is formed to have a minimum necessary size for transmitting the optical signal from each light emitting element 42 to the outside through the gas barrier film 13, and each opening of the barrier film 13 The surface other than the portion 51b is covered with the light shielding film 51. As shown in FIG. This configuration suppresses the influence of disturbance light on optical transmission as much as possible.

In Modified Example 1, each opening 51b of the structure 30 is directly provided with the corresponding light receiving section 54 . Each light receiving unit 54 is arranged outside the gas barrier film 13 so as to face the corresponding light emitting element 42 with only the gas barrier film 13 interposed therebetween. The light-receiving unit 54 includes a light-receiving element that receives the optical signal transmitted from the light-receiving unit 53 and transmitted through the gas barrier film 13 . It is possible to obtain an electric signal indicating the state inside the cell 21 in which the light receiving portion 53 is arranged. An LED element, a phototransistor, or the like can be used as the light receiving element, and the LED element is preferable. The light receiving section 54 may be a light receiving element mounted on a wiring substrate, or the light receiving section 54 may be the light receiving element itself.

In Modified Example 1, the surface of the gas barrier film 13 transparent to the optical signal is covered with the light shielding film 51 except for the plurality of openings 51b, and each light receiving section 54 is arranged in the corresponding opening 51b. The opening 51b is closed, and substantially the entire surface of the structure 30 is covered with the light shielding film. In this state, optical signals are transmitted and received through the gas barrier film 13 between the light-emitting element 42 of the light-emitting section 12 and the light-receiving section 54 in the structure 30 . According to Modification 1, it is not necessary to dispose the light guide section inside the gas barrier film 13 or draw out part of it to the outside of the gas barrier film 13, so the internal configuration of the battery module is greatly simplified. In addition, reliable sealing of the battery pack 11 by the gas barrier film 13 is obtained. Furthermore, by appropriately providing a light shielding film, it is possible to realize a battery module capable of performing efficient optical transmission while suppressing the influence of disturbance light on optical transmission as much as possible.

In Modification 1, the corresponding light receiving section 54 is directly connected to each opening 51b of the structure 30 without arranging an optical component such as an optical conduit between the light emitting element 42 of the light emitting section 12 and the light receiving section 54. is provided in This simplifies not only the internal configuration of the structural body 30 but also the external configuration of the structural body 30, realizing a simple battery module with a reduced number of parts.

In Modified Example 1, each light receiving section 54 is arranged so as to correspond to the light emitting section 12 arranged for each unit cell 21 constituting the assembled battery 12 . Therefore, the optical signal from each unit cell 21 can be independently received by the corresponding light receiving unit 54, and the state of each unit cell 21 (whether there is an abnormality in the voltage or temperature of the unit cell 21) can be recognized. be able to.

When manufacturing the battery module of Modification 1, for example, in the same manner as in the manufacturing method 1 described in the second embodiment, the light shielding film 51 is formed by printing or the like on the entire surface of the first gas barrier film 101 which is a strip-shaped transparent film. It is conceivable to form each opening 51b in the structure 20 after forming the individual structures 20 using the main film 201 coated with .

Further, in the same manner as in the manufacturing method 2 described in the second embodiment, after forming the individual structures 10 using the first gas barrier film 101 and the second gas barrier film 102 which are strip-shaped transparent films, the gas barrier film 13 is formed. The structure 20 having the openings 51b may be formed by forming the light shielding film 51 on the entire surface of the gas barrier film 13 while masking the portions where the openings 51b are to be formed, and removing the masking. good.

In addition, in the same manner as in the manufacturing method 3 described in the second embodiment, on the surface of the first gas barrier film 101, the formation planned portions of the openings 51b when the structure 20 is formed, that is, the first gas barrier film 101 Individual structures 20 having respective openings 51b are formed using a main film 301 formed by printing a light shielding film 51 except for the portions to be formed located on the side surfaces of the recesses 101a to be formed. can be

(Modification 2)
FIG. 17 is a schematic cross-sectional view showing the configuration of Modification 2 of the battery module of the second embodiment.
The battery module 1 of Modification 2 includes an assembled battery 11, a plurality of light emitting units 12, a gas barrier film 13, a light shielding film 51 on the gas barrier film 13, light shielding fins 55, a light receiving unit 15, and a battery state analyzer 16. It is configured. The assembled battery 11 and the plurality of light emitting units 12 are covered and sealed with the gas barrier film 13, and the structure including the gas barrier film 13 and the light shielding film 51 is the structure 20 as in the second embodiment.

In Modified Example 2, a light shielding fin 55 is provided so as to cover the window 51a formed in the structure 20 . The light shielding fin 55 has a surface covered with a light shielding film similar to the light shielding film 51 .
The light-shielding fin 55 is attached with the light-receiving section 15 having the light-receiving element 45 as in the first embodiment. The light receiving section 15 is a common light receiving section for the plurality of light emitting sections 12 .

In Modification 2, the surface of the gas barrier film 13 transparent to the optical signal is covered with the light shielding film 51 except for the window 51a, and the light shielding fins 55 are arranged so as to cover the window 51a. Substantially the entire surface of the body 20 is covered with a light shielding film. In this state, optical signals are transmitted and received between the light emitting element 42 of the light emitting section 12 and the light receiving section 15 in the structure 20 via the gas barrier film 13 . According to Modification 2, it is not necessary to dispose the light guide section inside the gas barrier film 13 or pull out part of it to the outside of the gas barrier film 13, so the internal configuration of the battery module is greatly simplified. In addition, reliable sealing of the battery pack 11 by the gas barrier film 13 is obtained. Furthermore, by appropriately providing a light shielding film, it is possible to realize a battery module capable of performing efficient optical transmission while suppressing the influence of disturbance light on optical transmission as much as possible.

Further, in Modification 2, the window portion 51a of the structure 20 and the light shielding fin 55 are arranged without arranging an optical component such as an optical conduit in the light shielding fin 55 (between the light emitting element 42 of the light emitting portion 12 and the light receiving portion 15). A light receiving portion 15 is directly provided in a state separated by . This simplifies not only the internal configuration of the structural body 20 but also the external configuration of the structural body 20, realizing a simple battery module with a reduced number of parts.

The embodiments and modifications described above are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. Flowcharts, sequences, components provided in the embodiments and their arrangement, materials, conditions, shapes and sizes, etc., described in the embodiments and modifications are not limited to those illustrated, and may be changed as appropriate. can be done. Also, it is possible to partially replace or combine the configurations shown in different embodiments.

As described above, the battery module according to one embodiment of the present invention includes a positive electrode current collector including a resin current collector layer and a positive electrode active material layer including a positive electrode active material formed on the positive electrode current collector. a negative electrode having a negative electrode current collector including a resin current collector layer and a negative electrode active material layer including a negative electrode active material formed on the negative electrode current collector; the positive electrode active material layer and the negative electrode active material an assembled battery in which a plurality of lithium-ion cells are stacked, and a separator disposed between layers; and a gas barrier film covering the assembled battery, the gas barrier film as a whole being transparent to the optical signal.

In the above embodiment, the light emitting section may transmit the optical signal to the outside through the gas barrier film.

In the above embodiment, a light guide tube may be provided outside the gas barrier film so as to cover the plurality of light emitting portions via the gas barrier film.

In the above embodiment, a light receiving section may be provided outside the gas barrier film to receive the plurality of optical signals propagating inside the light guide tube.

In the above embodiment, a light receiving section may be provided outside the gas barrier film to directly receive the optical signal transmitted from the light emitting section through the gas barrier film.

In the above embodiment, the gas barrier film may be provided with a light shielding layer for shielding the optical signal on a part of the surface, and may not be provided with the light shielding layer at a position corresponding to the light emitting portion on the surface.

In the above embodiment, the surface of the gas barrier film may be covered with the light shielding layer except for the portion aligned with the region including the plurality of light emitting portions.

In the one embodiment described above, the surface of the gas barrier film may be covered with the light shielding layer except for the portions where the positions of the light emitting portions are aligned.

A method for manufacturing a battery module according to an embodiment of the present invention is the above-described method for manufacturing a battery module, wherein the surface of a strip-shaped first gas barrier film that becomes the gas barrier film that is transparent to the optical signal as a whole is a step of sequentially forming a plurality of recesses by heat molding; and a step of sequentially fitting a structure including the assembled battery and a plurality of light emitting portions provided for each of the unit cells into the recesses. a step of successively sealing a plurality of the structures by overlapping a strip-shaped second gas barrier film on the first gas barrier film; and a step of cutting the first gas barrier film and the second gas barrier film for each structure. , has

In the above embodiment, the band-shaped first gas barrier film, which is subjected to the step of forming the recesses, is covered with the light-shielding layer except for a portion aligned with the region including the plurality of light-emitting portions, and the band-shaped first gas barrier film is When the concave portion is formed in the first gas barrier film, the portion may be located on the side surface of the concave portion.

In the above embodiment, the strip-shaped first gas barrier film provided for the step of forming the recesses is covered with the light-shielding layer except for a portion aligned with each light-emitting portion, and the strip-shaped first gas barrier film is covered with the light-shielding layer. The portion may be positioned on the side surface of the recess when the recess is formed in the .

--Second aspect of the invention--
Next, a secondary battery module according to a second aspect of the invention will be described.

High energy density lithium-ion batteries are known as batteries that can be used as power sources for electric vehicles and hybrid electric vehicles. Also known is a configuration in which a laminated battery having a structure in which a plurality of lithium ion batteries are laminated (for example, JP-A-2021-34141) is housed in an exterior body such as a laminated film.

When the laminated battery is housed in the outer package, the entire laminated battery is covered with the outer package and vacuumed (vacuum packed). At this time, for example, if air remains inside the laminated battery, there is a risk that the laminated battery will not adhere well even if it is evacuated.

Therefore, an object of the second aspect of the invention is to provide a secondary battery module capable of suppressing air from remaining inside the laminated battery.

As a result of extensive research based on the above knowledge, we came up with the following aspects.

[1]
A secondary battery module comprising a laminated battery in which a plurality of storage elements each having a negative electrode current collector, a negative electrode active material layer, a separator or a solid electrolyte, a positive electrode active material layer, and a positive electrode current collector are stacked,
A current extraction layer is in contact with at least one surface of the outermost layer in the laminated battery,
A small hole penetrating vertically is formed in the current extraction layer,
Secondary battery module.

[2]
The small holes are either circular, elliptical, or slit-shaped in plan view,
The secondary battery module according to [1].

[3]
When the small hole has an elliptical shape, the dimension of the minor axis of the elliptical shape is 0.2 mm to 2 mm,
When the small hole is circular, the radius of the circular shape is 0.2 mm to 2 mm.
The secondary battery module according to [1] or [2].

[4]
A plurality of the small holes are formed in the current extraction layer, and relatively more small holes are formed in the central portion of the current extraction layer than in the peripheral portion of the current extraction layer.
The secondary battery module according to any one of [1] to [3].

[5]
The current extraction layer includes a positive current extraction layer and a negative current supply layer,
The positive electrode-side current extraction layer and the negative electrode-side current supply layer are made of an elastic material that is elastically deformable,
The secondary battery module according to any one of [1] to [4].

[6]
wherein the current extraction layer is made of a non-woven fabric,
The secondary battery module according to any one of [1] to [5].

[7]
A PTC thermistor is interposed between the positive current collector and the positive current extraction layer.
The secondary battery module according to any one of [1] to [6].

[8]
A PTC thermistor is interposed between the negative electrode current collector and the negative electrode current supply layer.
The secondary battery module according to any one of [1] to [7].

[9]
The positive electrode-side current extraction layer includes a plurality of current extraction portions and a plurality of positive electrode conductive wires for electrically connecting each of the current extraction portions to the positive electrode confluence portion. are substantially identical to each other,
The secondary battery module according to [7] or [8].

[10]
Above the positive electrode current collector, a positive electrode rectifying section that delivers current during discharge extends in the width direction.
The secondary battery module according to any one of [1] to [9].

According to the aspect of the present invention, it is possible to provide a secondary battery module that can prevent air from remaining inside the laminated battery.

Hereinafter, various embodiments according to aspects of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
Hereinafter, the secondary battery module according to the first embodiment will be described in detail with reference to the drawings.

FIG. 18 is a perspective view showing a secondary battery module 401 according to a first embodiment to which aspects of the present invention are applied, and FIG. 19 shows a side sectional view thereof. In the secondary battery module 401, a negative electrode 402 composed of a negative electrode current collector 411 and a negative electrode active material layer 412 and a positive electrode 403 composed of a positive electrode active material layer 414 and a positive electrode current collector 415, which are power storage elements, are connected to a separator 413. It is configured as a battery cell 420 consisting of a laminated battery (single battery) on a flat plate that is laminated with an intervening layer. That is, in the battery cell 420 constituting the secondary battery module 401, the negative electrode current collector 411, the negative electrode active material layer 412, the separator 413, the positive electrode active material layer 414, and the positive electrode current collector 415 face upward in FIG. are laminated together, and formed in a substantially rectangular flat plate shape as a whole.

The secondary battery module 401 further includes an annular frame member 9 arranged around the periphery of the battery cells 420 . The edge of the separator 413 is embedded in the frame member 409 to support the separator 413, and the frame member 409 brings the positive electrode current collector 415 and the negative electrode current collector 411 into surface contact with the upper surface and the lower surface of the frame member 409. They are fixed on top of each other. By fixing the peripheral edge portions of the negative electrode current collector 411, the positive electrode current collector 415, and the separator 413 via the frame member 409, the negative electrode active material layer 412 and the positive electrode active material layer 414 are firmly prevented from leaking to the outside. It becomes possible to seal to Further, the frame member 409 can determine the positional relationship among the negative electrode current collector 411 , the separator 413 , and the positive electrode current collector 415 . The gap between the negative electrode current collector 411 and the separator 413 and the gap between the separator 413 and the positive electrode current collector 415 are adjusted in advance according to the capacity of the battery. A negative electrode current collector 411, a separator 413, and a positive electrode current collector 415 can be fixed to each other.

A negative electrode current supply layer 410 as a conductor layer is laminated on the lower side of the negative electrode current collector 411 in a planar shape, and a positive electrode current extraction layer, which is also a conductor layer, is laminated on the upper side of the positive electrode current collector 415 . 416 are stacked in a plane. The negative current supply layer 410 and the positive current extraction layer 416 are provided with

conductive portions

407 and 408 to which current is supplied, respectively.

The battery cell 420 is composed of a so-called lithium-ion secondary battery. FIG. 20A shows an enlarged cross-sectional view of a battery cell 420 as a lithium ion secondary battery. The constituent positive electrode active material layer 414 contains a positive electrode active material 442 and an electrolytic solution 443 .

When such a battery cell 420 is operated as a lithium ion secondary battery, first, the positive terminal of a charger (not shown) is connected to the positive electrode 403 side and the negative electrode terminal of the charger is connected to the negative electrode 402 side to allow current to flow. As a result, electrons separated from the positive electrode active material 442 containing lithium-transition metal composite oxide or the like flow through an external circuit including a charger and reach the negative electrode active material 441 made of a carbonaceous material or the like. In the meantime, positively charged lithium ions are attracted to the negative electrode 402 side, flow through the electrolytic solution 443, reach the negative electrode active material 441, and are occluded therein. When all the lithium atoms in the positive electrode active material 442 reach the negative electrode active material 441, the battery cell 420 is fully charged.

An external load (not shown) is connected between the positive electrode 403 and the negative electrode 2 during discharging. As a result, the lithium ions occluded in the negative electrode active material 441 return to a stable state as part of the lithium-transition metal composite oxide, so they pass through the electrolytic solution 443 and move toward the positive electrode. Energy is also consumed when electrons flow from the negative electrode 402 through an external load to the positive electrode 3 side. By placing the separator 413 as an insulating layer between the positive electrode 403 and the negative electrode 402, only lithium ions are allowed to permeate while preventing an internal short circuit between the positive electrode 403 and the negative electrode 2, thereby reducing the risk of explosion or fire. can be suppressed.

A description will be given of preferred aspects of the materials that make up each component when the battery cell 420 is realized with such a lithium-ion secondary battery.

As the positive electrode active material 442 contained in the positive electrode active material layer 414, a lithium transition metal composite oxide, that is, a composite oxide of lithium and a transition metal {composite oxide containing one type of transition metal (LiCoO ₂ , LiNiO ₂ , LiAlMnO ₄ , LiMnO ₂ and LiMn ₂ O ₄ , etc.), composite oxides containing two transition metal elements (e.g., LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _{1/ 3Co1} _/3Al1 _/ _3O2 _and _{LiNi0.8Co0.15Al0.05O2} ) and _composite oxides _containing _three _or more metal elements [ _e.g. _O ₂ (M, M′ and M _″ are different transition metal elements, satisfying a+ _b + _c =1. Metal phosphates (e.g. _LiFePO4 , _LiCoPO4 , _LiMnPO4 and _LiNiPO4 ), transition metal oxides ( _e.g. _MnO2 and _V2O5 ), transition metal sulfides (e.g. _MoS2 and _TiS2 ) and highly conductive Molecules such as polyaniline, polypyrrole, polythiophene, polyacetylene and poly-p-phenylene and polyvinylcarbazole, and the like. For the positive electrode active material 442, two or more of the lithium-transition metal composite oxides and the like described above may be used in combination. The lithium-containing transition metal phosphate may have a transition metal site partially substituted with another transition metal.

The positive electrode active material 442 is preferably a coated positive electrode active material coated with a conductive aid and a coating resin. By covering the positive electrode active material 442 with the covering resin, the volume change of the electrode is alleviated, and the expansion of the electrode can be suppressed.

Conductive agents include metallic conductive agents [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon-based conductive agents [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), and mixtures thereof. These conductive aids may be used singly or in combination of two or more. Conductive aids may also be used as these alloys or metal oxides. From the viewpoint of electrical stability, the conductive aid is more preferably composed of aluminum, stainless steel, silver, gold, copper, titanium, carbon-based conductive aids, and mixtures thereof. Among them, the conductive aid is more preferably composed of silver, gold, aluminum, stainless steel, and a carbon-based conductive aid, and particularly preferably composed of a carbon-based conductive aid.

Also, as these conductive aids, a particle-based ceramic material or a resin material coated with a conductive material by plating or the like may be applied. It is preferable that the conductive material to be coated is made of a metal among the above-described conductive aids.

The form of the conductive aid is not limited to the particle form, and may be in a form other than the particle form. good.

As the coating resin, a material described as a non-aqueous secondary battery active material coating resin described in JP-A-2017-054703 may be used.

The ratio of the coating resin and the conductive aid is not particularly limited, but from the viewpoint of the internal resistance of the battery, etc., the weight ratio of the coating resin (resin solid content weight): conductive aid is 1:0. 0.01 to 1:50, more preferably 1:0.2 to 1:3.0.

The positive electrode active material 442 may further contain a conductive aid in addition to the conductive aid contained in the coated positive electrode active material. As the conductive aid to be further included, the same conductive aid as the conductive aid contained in the above-described coated positive electrode active material can be preferably used.

The positive electrode active material 442 is preferably a non-binding material that does not contain a binder that binds the positive electrode active materials 442 together. Here, the non-binding body means that the positive electrode active materials 442 are irreversibly fixed to each other and the positive electrode active material 442 and the current collector without fixing the positions of the positive electrode active materials 442 by a binder as a so-called binder. It means the state of not When the positive electrode active materials 442 are non-bound, the positive electrode active materials 442 are not irreversibly fixed to each other, and thus the interfaces between the positive electrode active materials 442 can be separated without mechanical destruction. , even when stress is applied to the positive electrode active material layer 414, the positive electrode active material 442 moves, so that the positive electrode active material layer 414 can be prevented from being broken. The positive electrode active material layer 414 containing the positive electrode active material 442 which is a non-binder, the positive electrode active material 442 and the electrolytic solution 443 and containing no binder can be obtained by a method such as the following.

In this specification, the binder means an agent that cannot reversibly fix the positive electrode active materials 442 together and the positive electrode active material 442 and the current collector, and includes starch, polyvinylidene fluoride, and polyvinyl alcohol. , carboxymethylcellulose, polyvinylpyrrolidone, tetrafluoroethylene, styrene-butadiene rubber, polyethylene and polypropylene, and other known solvent-drying binders for lithium ion batteries. These binders are used by dissolving or dispersing them in a solvent, and by volatilizing and distilling off the solvent, the surfaces of the positive electrode active materials 442 are solidified without exhibiting stickiness. It cannot be reversibly fixed to the body.

The positive electrode active material layer 414 may contain an adhesive resin in addition to the positive electrode active material 442 described above. As the adhesive resin, for example, a non-aqueous secondary battery active material coating resin described in JP-A-2017-054703 is mixed with a small amount of an organic solvent to adjust its glass transition temperature to room temperature or lower. Also, those described as adhesives in JP-A-10-255805 can be preferably used.

The sticky resin means a resin that does not solidify and has stickiness even when the solvent component is volatilized and dried. The tackiness as used herein means the property of adhering by applying a slight pressure without using water, solvent, heat, or the like. On the other hand, a solution-drying type electrode binder used as a binding agent is one that dries and solidifies by volatilizing a solvent component to firmly adhere and fix active materials together. Therefore, the solution-drying type electrode binder and the adhesive resin are different materials.

Although the thickness of the positive electrode active material layer 414 is not particularly limited, it is preferably 150 μm to 600 μm, more preferably 200 μm to 450 μm, from the viewpoint of battery performance.

As the negative electrode active material 441 contained in the negative electrode active material layer 412, a known negative electrode active material for lithium ion batteries can be used, and carbon-based materials [graphite, non-graphitizable carbon, amorphous carbon, baked resin (for example, phenolic resin and carbonized furan resin, etc.), cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), carbon fibers, etc.], silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composite bodies (carbon particles coated with silicon and/or silicon carbide, silicon particles or silicon oxide particles coated with carbon and/or silicon carbide, silicon carbide, etc.) and silicon alloys (silicon-aluminum alloys , silicon-lithium alloys, silicon-nickel alloys, silicon-iron alloys, silicon-titanium alloys, silicon-manganese alloys, silicon-copper alloys, silicon-tin alloys, etc.)], conductive polymers (e.g., polyacetylene and polypyrrole, etc.) ), metals (such as tin, aluminum, zirconium and titanium), metal oxides (such as titanium oxide and lithium-titanium oxide) and metal alloys (such as lithium-tin alloys, lithium-aluminum alloys and lithium-aluminum-manganese alloys) etc.) and the like, and mixtures of these with carbonaceous materials.

Further, the negative electrode active material 441 may be composed of a coated negative electrode active material coated with a conductive aid and a coating resin similar to the coated positive electrode active material described above. As the conductive aid and the coating resin, the same conductive aid and coating resin as those for the coated positive electrode active material described above can be suitably used.

The negative electrode active material layer 412 may further contain a conductive aid in addition to the conductive aid contained in the coated negative electrode active material. As the conductive aid to be further included, the same conductive aid as the conductive aid contained in the above-described coated positive electrode active material can be preferably used.

Like the positive electrode active material layer 414, the negative electrode active material layer 412 is preferably a non-binding material that does not contain a binder that binds the negative electrode active materials 441 together. Further, like the positive electrode active material layer, it may contain an adhesive resin.

Although the thickness of the negative electrode active material layer 412 is not particularly limited, it is preferably 150 μm to 600 μm, more preferably 200 μm to 450 μm, from the viewpoint of battery performance.

For the electrolytic solution 443 contained in each of the negative electrode active material layer 412 and the positive electrode active material layer 414, a known electrolytic solution containing an electrolyte and a non-aqueous solvent, which is used for manufacturing known lithium ion batteries, can be used.

The electrolytic solution 443 can ensure a so-called high electrical conductivity, which allows a large number of lithium ions to move between the negative electrode 402 and the positive electrode 403 at high speed, and has electrochemical stability (oxidation resistance during charging). The most suitable material is selected from the viewpoints of properties, resistance to reduction during discharge) and thermal stability, and a substance containing lithium ions serving as charge carriers is applied. Examples of the electrolytic solution 443 include inorganic acid lithium salts such as LiN(FSO ₂ ) ₂ , LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ and LiClO ₄ , LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ and lithium salts of organic acids such as LiC(CF ₃ SO ₂ ) ₃ and the like. Among these, imide-based electrolytes [LiN( _FSO2 ) ₂ , LiN( _CF3SO2 ) ₂ , LiN( _C2F5SO2 ) ₂ _, _etc. _] and _LiPF6 .

As the non-aqueous solvent, those used in known electrolytic solutions can be used. compounds, amide compounds, sulfones, sulfolane, etc. and mixtures thereof can be used. The non-aqueous solvent may be used singly or in combination of two or more.

Among non-aqueous solvents, preferred from the viewpoint of battery output and charge-discharge cycle characteristics are lactone compounds, cyclic carbonates, chain carbonates and phosphates, and more preferred are lactone compounds, cyclic carbonates and chains. carbonic acid ester, more preferably a mixture of a cyclic carbonate and a chain carbonic acid ester. Propylene carbonate (PC) or a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) is particularly preferred.

The electrolyte concentration of the electrolytic solution 443 is preferably 1 mol/L to 5 mol/L, more preferably 1.5 mol/L to 4 mol/L, and even more preferably 2 mol/L to 3 mol/L. .

If the electrolyte concentration of the electrolytic solution 443 is less than 1 mol/L, sufficient input/output characteristics of the battery may not be obtained, and if it exceeds 5 mol/L, the electrolyte may precipitate.

The electrolyte concentration of the electrolyte solution 443 can be confirmed by extracting the electrolyte solution 443 forming the battery cell 420 without using a solvent or the like and measuring the concentration.

Materials constituting the negative electrode current collector 411 and the positive electrode current collector 415 include metal materials such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof, baked carbon, conductive polymer materials, and conductive materials. Glass etc. are mentioned. Among these materials, aluminum is preferable for the positive electrode current collector 415 and copper is preferable for the negative electrode current collector 411 from the viewpoint of weight reduction, corrosion resistance, and high conductivity.

Among them, the negative electrode current collector 411 and the positive electrode current collector 415 are preferably resin current collectors made of a conductive polymer material. As the conductive polymer material constituting the resin current collector, for example, a conductive polymer or a matrix resin to which a conductive agent is added as necessary can be used. As the conductive agent that constitutes the conductive polymer material, the same conductive aid as that contained in the above-described coated positive electrode active material can be preferably used.

Examples of resins constituting the conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyethernitrile (PEN), poly Tetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin or mixtures thereof etc. From the viewpoint of electrical stability, it is preferable to use polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), and polycycloolefin (PCO) as resins constituting the conductive polymer material. More preferably, polyethylene (PE), polypropylene (PP) and polymethylpentene (PMP) are applied.

In the case of forming a resin current collector by adding a conductive agent to a matrix resin, the conductive agent may be composed of a conductive filler. Conductive fillers include metals [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.], carbon-based materials [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.). ), etc.], and mixtures thereof, among which carbon-based materials are preferred. If the conductive filler is a carbon-based material, it is possible to prevent the negative electrode active material 441 and the positive electrode active material 442 from being mixed with metal derived from the negative electrode current collector 411 and the positive electrode current collector 415 . Especially in the positive electrode active material 442, it leads to suppression of characteristic deterioration.

Such conductive fillers may be used singly or in combination of two or more. Also, the conductive filler may be an alloy of the above metals or a metal oxide. Also, the conductive filler may be a particulate ceramic material or a resin material coated with a conductive material composed of the above-described metal or the like by plating or the like.

The average particle size of the conductive filler is not particularly limited, but from the viewpoint of the electrical characteristics of the battery, it is preferably 0.01 μm to 10 μm, more preferably 0.02 μm to 5 μm. More preferably, it is between 0.03 μm and 1 μm.

In addition, the shape (form) of the conductive filler is not limited to the particle form, and may be in a form other than the particle form. may

The conductive filler may be a conductive fiber having a fibrous shape. Examples of conductive fibers include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers obtained by uniformly dispersing highly conductive metals and graphite in synthetic fibers, and metals such as stainless steel. Examples include fibrillated metal fibers, conductive fibers obtained by coating the surface of organic fibers with metal, and conductive fibers obtained by coating the surfaces of organic fibers with a resin containing a conductive substance. Among these conductive fibers, the conductive filler is preferably carbon fiber, or a polypropylene resin in which graphene is kneaded. Incidentally, when the conductive filler is conductive fiber, the average fiber diameter is preferably 0.1 μm to 20 μm.

The weight ratio of the conductive filler in the negative electrode current collector 411 and the positive electrode current collector 415 is preferably 5% to 90% by weight, more preferably 20% to 80% by weight. In particular, when the conductive filler is carbon, the weight ratio of the conductive filler is preferably 20% by weight to 30% by weight.

The resin current collector may contain other components (dispersant, cross-linking accelerator, cross-linking agent, colorant, ultraviolet absorber, plasticizer, etc.) in addition to the matrix resin and the conductive filler. Also, a plurality of resin current collectors may be laminated and used, or a resin current collector and a metal foil may be laminated and used.

Although the thickness of the negative electrode current collector 411 and the positive electrode current collector 415 is not particularly limited, it is preferably 5 μm to 150 μm. When a plurality of resin current collectors are laminated and used as the negative electrode current collector 411 and the positive electrode current collector 415, the total thickness after lamination is preferably 5 μm to 150 μm.

The negative electrode current collector 411 and the positive electrode current collector 415 are formed by, for example, a conductive resin composition obtained by melt-kneading a matrix resin, a conductive filler, and a dispersing agent for a filler used if necessary, and formed into a film by a known method. can be obtained by Methods for forming such a conductive resin composition into a film include, for example, known film forming methods such as a T-die method, an inflation method and a calender method. The negative electrode current collector 411 and the positive electrode current collector 415 can also be obtained by a molding method other than film molding.

The shape of the negative electrode current collector 411 and the positive electrode current collector 415 is not particularly limited, and may be a sheet body or a plate-like body made of the above materials, or a deposited layer made of fine particles made of the above materials. The thicknesses of the negative electrode current collector 411 and the positive electrode current collector 415 are not particularly limited, but are preferably 50 μm to 500 μm.

The separator 413 is made of a polyolefin such as polyethylene (PE) or polypropylene (PP), a porous film made of aromatic polyamide, a porous polyethylene film and a porous polypropylene, from the viewpoint of the required electrical insulation and ion conductivity. Laminated films with, synthetic resins such as polyester fibers and aramid fibers, or non-woven fabrics made of glass fibers, fluorine resins, etc., and those with ceramic fine particles such as silica, alumina, and titania attached to their surfaces are applied. . The material forming the separator 413 is not limited to the above-described example, and it is a matter of course that a known separator material for a lithium ion secondary battery may be applied.

Materials constituting the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 are metals such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof, like the negative electrode current collector 411 and the positive electrode current collector 415. materials, as well as calcined carbon, conductive polymeric materials, conductive glass, and the like. At this time, the negative electrode-side current supply layer 410 and the positive electrode-side current extraction layer 416 may be composed of a resin current collector made of a conductive polymer material. As the molecular material, for example, a conductive polymer or a matrix resin to which a conductive agent made of a conductive filler is added as needed may be used. As the conductive filler, the same material as the resin current collector described above can be applied, but it is also possible to apply a conductive elastomer obtained by melt-mixing the conductive filler and a rubber-like polymer. be. Examples of rubber-like polymers include silicone, urethane, neoprene, butyl rubber, ethene-propene rubber, acrylate rubber, butadiene rubber, coloprene rubber, nitrile rubber, 1-1 propene rubber, fluororubber, styrene-butadiene, natural rubber, and combinations thereof. is applicable.

The materials constituting the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 are either or both of the negative electrode current supply layer 410 and the positive electrode current extraction layer 416, such as a conductive polymer material, carbon fiber, or the like. It may be composed of an elastic material that can be elastically deformed, such as a nonwoven fabric made of. Since the negative current supply layer 410 and the positive current extraction layer 416 are elastically deformable, the negative current collector 411, the positive current collector 415, and the frame member 409 are fixed in a state where the adhesiveness is enhanced. becomes possible. By elastically pressing the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 to fix them to the negative electrode active material layer 412, the positive electrode active material layer 414, and the frame member 409, an air layer is formed between them. can be prevented, and the resistance can be kept low and uniformized. When one or both of the negative current supply layer 410 and the positive current extraction layer 416 are made of a non-woven fabric made of carbon fiber or the like, if the current distribution is suppressed, a hard material whose volume change is small even under normal conditions is used. In the carbon-based nonwoven fabric, the distribution of volume change is further reduced, and it is possible to achieve further extension of life. In some cases, small holes are naturally formed in the meshes of the fibers of the nonwoven fabric, and there is a possibility that small holes may be naturally formed between the negative electrode current supply layer 410 or the positive electrode current extraction layer 416 and the negative electrode current collector 411 or the positive electrode current collector 415 . Air bubbles that form in the can escape through this small hole. The negative electrode-side current supply layer 410 is not limited to being configured separately from the negative electrode current collector 411, and may be integrated with each other. Similarly, the positive electrode-side current extraction layer 416 is not limited to being configured separately from the positive electrode current collector 415, and may be integrated with each other.

The material forming the frame member 409 is not particularly limited as long as it has adhesiveness to the negative electrode current collector 411 and the positive electrode current collector 415 and is durable to the electrolytic solution 443 . Materials, especially thermosetting resins, are preferred. Specific examples of the material forming the frame member 409 include epoxy-based resin, polyolefin-based resin, polyurethane-based resin, and polyvinylidene fluoride resin. Epoxy-based resin is preferred because of its high durability and ease of handling. preferable.

As a method for manufacturing the battery cell 420 composed of the unit cell having the above-described structure, for example, the negative electrode current collector 411, the negative electrode active material layer 412, the separator 413, the positive electrode active material layer 414, and the positive electrode current collector 415 are stacked in this order. After that, the electrolytic solution 343 is injected, the outer circumferences of the negative electrode active material layer 412, the separator 413 and the positive electrode active material 414 are sealed with the frame member 9, and further the negative electrode side current supply layer 410 and the positive electrode side current extraction layer 416 are laminated. can be obtained by letting As a method for sealing the outer periphery of the negative electrode active material layer 412 and the positive electrode active material layer 414 with the frame member 409, the negative electrode active material layer 412 and the positive electrode active material layer 414 are bonded to the upper and lower surfaces of one frame member 409. A lithium-ion secondary battery consisting of a single cell is produced by a method in which one frame member 409 and the other frame member 409 are adhered and sealed in a state where the separator 413 is inserted in the other frame member 409. A cell 420 can be obtained.

21A and 21B show an example of forming a positive current extraction layer 416 on a positive current collector 415 for a battery cell 420 in a secondary battery module 401. FIG.

As shown in FIG. 21A, when the positive electrode current extraction layer 416 is formed on the positive electrode current collector 415 described above, air bubbles 481 may be naturally formed. In such a case, this battery cell 420 is placed in a reduced pressure environment for a certain period of time. In such a case, the battery cell 420 is placed in, for example, a pressure-reduced constant temperature bath and the pressure is reduced. As a result, as shown in FIG. 21B, it is possible to remove air bubbles formed between the positive current collector 415 and the positive current extraction layer 416 . Similarly, even when air bubbles are formed between the negative electrode-side current supply layer 410 and the negative electrode current collector 411, the air bubbles can be removed by placing them in a reduced pressure environment.

By removing air bubbles in this way, adhesion between the positive current collector 415 and the positive current extraction layer 416 and between the negative current supply layer 410 and the negative current collector 411 is improved. It will happen.

In addition, in the battery cell 420 having the above-described configuration, a battery cell 420' configured with a so-called all-solid lithium ion battery using a solid electrolyte 446 as shown in FIG. 20B instead of the liquid electrolytic solution 443 is substituted. You may do so. In the battery cell 420 ′, the configuration of the separator 413 is omitted, and the entire area from the negative electrode 402 to the positive electrode 403 is filled with the solid electrolyte 446 . In the negative electrode active material layer 412 , the negative electrode active material 441 is interposed in the solid electrolyte 446 . In the cathode active material layer 414 , the cathode active material 442 is interposed in the solid electrolyte 446 . The details and materials of the components that make up the battery cell 420′ are the same as the components that make up the battery cell 420, so the same reference numerals are used to omit the description below. do.

Solid electrolyte 446 includes known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid electrolyte 446 contains a supporting salt (lithium salt) to ensure ionic conductivity. LiBF ₄ , LiPF ₆ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used as the supporting salt. However, polyalkylene oxide polymers such as PEO and PPO that constitute the solid electrolyte 446 are lithium such as LiBF ₄ , LiPF ₆ , LiN(SO ₂ CF ₃ ) ₂ and LiN(SO ₂ C ₂ F ₅ ) ₂ . It has the property of being able to dissolve salts well, and by forming a crosslinked structure between the two, excellent mechanical strength can be exhibited.

According to the battery cell 420' using the above-described solid electrolyte 446 as an electrolyte, since the electrolyte has no fluidity, a sealing structure for preventing the electrolyte from flowing out is not required, thereby simplifying the configuration of the secondary battery module 401. becomes possible. In addition, according to the battery cell 420 ′, by using a solid electrolyte, it is possible to prevent liquid leakage, prevent liquid junction, which is a problem unique to lithium ion secondary batteries, and improve reliability. can be improved.

It should be noted that the secondary battery module 401 to which the aspect of the present invention is applied is not limited to the case where the battery cells 420 of the lithium ion secondary battery are composed of single cells. For example, as shown in FIG. 22, an assembled battery 450 may be formed by stacking and connecting a plurality of battery cells 420 .

When forming such an assembled battery 450, by connecting a plurality of battery cells 420 in series, the conductive portion 408 connected to the positive electrode side current extraction layer 416 of the battery cell 420 at the top and the battery at the bottom are connected. A current may be freely supplied through the conductive portion 407 connected to the negative current supply layer 410 of the cell 420 . In such a case, the battery cells 20 that are connected to each other are stacked such that the lower surface of the negative electrode current supply layer 410 and the upper surface of the positive electrode current extraction layer 416 are adjacent to each other. Furthermore, when forming such an assembled battery 450, a plurality of battery cells 420 may be connected in parallel, or series connection and parallel connection may be combined. A high capacity and high output can be obtained by configuring the assembled battery 450 in this way. Alternatively, the

conductive portions

407 and 408 connected to the negative current supply layer 410 and the positive current extraction layer 416 of each battery cell 420 may be configured to independently supply current.

The above-described first aspect of the invention may be applied to the assembled battery 450 to which the aspect of the invention is applied. For example, the assembled battery 11 of FIG. 1, the assembled battery 51 of FIGS. 14A, 14C, and 16B, etc. in the first aspect of the invention are replaced with the assembled battery 450 of the aspect of the invention, and the battery module according to the first aspect of the invention is obtained. can be considered.

Next, the operation of the secondary battery module 401 to which the present invention is applied will be described.

When an external load (not shown) of the secondary battery module is connected between the positive electrode 403 and the negative electrode 402 during discharge, electrons reaching the negative electrode current collector 411 from the negative electrode active material layer 412 are transferred to the negative electrode. It propagates on the negative electrode side current supply layer 410 in contact with the current collector 411 . Then, the electrons pass through the external load and propagate on the positive electrode side current extraction layer 416 of the positive electrode 403 .

In addition, during discharge, the lithium ions occluded in the negative electrode active material 441 move toward the positive electrode active material 442 .

According to the present invention configured as described above, air bubbles are removed under reduced pressure between the positive current collector 415 and the positive current extraction layer 416 and between the negative current supply layer 410 and the negative current collector 411. and the adhesion is improved. As a result, according to the aspect of the present invention, a current can flow uniformly without generating a local resistance distribution on the negative current supply layer 410 and the positive current extraction layer 416 . As a result, there are no areas where a large amount of current flows locally, the temperature does not rise locally in those areas, and a large current easily flows locally without a local decrease in resistance. You can avoid falling into a vicious circle. In this way, a large current does not flow locally on the negative current supply layer 410 and the positive current extraction layer 416, and the current distribution can be made uniform, thereby suppressing deterioration of the battery cell 420 itself. can be achieved, and by extension the life of the battery cell 420 can be increased.

In this embodiment, at least one of the negative current supply layer 410 and the positive current extraction layer 416 is formed with small holes penetrating vertically. FIG. 23A illustrates a case where a plurality of small holes 496 are formed vertically through the positive current extraction layer 416 . In this case, the following effects are obtained. When air bubbles 481 are formed between the positive electrode current collector 415 and the positive electrode-side current extraction layer 416 during manufacturing, the air in the air bubbles 481 can be reduced by placing them in a reduced pressure environment as shown in FIG. 23B. The bubbles 481 can be removed by passing through the holes 496 and being released to the outside.

By removing the air bubbles 481 in this manner, the adhesion between the positive electrode current collector 415 and the positive electrode current extraction layer 416 is improved. A small hole 496 penetrating vertically may be formed in the negative current extraction layer 410 . By removing air bubbles 481 formed between the negative electrode current collector 411 and the negative electrode current extraction layer 410 in the same manner as described above, adhesion between the negative electrode current collector 411 and the negative electrode current extraction layer 410 is improved. can be improved. In addition, by forming small holes 496 in both the negative electrode current supply layer 410 and the positive electrode current extraction layer 416, adhesion between the negative electrode current collector 411 and the negative electrode current extraction layer 410 and positive electrode collection can be improved. Both the adhesion between the conductor 415 and the positive current extraction layer 416 can be reliably improved.

As the material in which the small holes 496 are formed and which is applied to the negative current supply layer 410 and the positive current extraction layer 416, a non-woven fabric made of carbon fiber or the like has been described as an example, but the present invention is limited to this. It may be constructed of any material that is electrically conductive and in which the perforations 496 are formed.

The small hole 496 formed in the negative current supply layer 410 and/or the positive current extraction layer 416 has, for example, a circular shape, an elliptical shape, or a slit shape in plan view. When the small hole 496 is formed in an elliptical shape, the dimension of the minor axis of the elliptical shape is preferably 0.2 mm to 2 mm. When the small holes 496 are formed in a circular shape, the radius of the circular shape is preferably 0.2 mm to 2 mm.

If the dimension of the minor axis of the elliptical shape of the small hole 496 or the dimension of the radius of the circular shape is less than 0.2 mm, the gap between the negative electrode current collector 411 and the negative electrode current extraction layer 410 and/or the positive electrode current collector Air bubbles 481 generated between 415 and positive electrode-side current extraction layer 416 may not be completely removed, and air bubbles 481 may not be sufficiently removed. Further, if the dimension of the minor axis of the elliptical shape of the small hole 496 or the dimension of the radius of the circular shape exceeds 2 mm, it is difficult for the current to flow in the plane of the negative electrode current extraction layer 410 and/or the positive electrode current extraction layer 416. parts may occur. By setting the dimension of the minor axis of the elliptical shape of the small hole 496 or the dimension of the radius of the circular shape to 0.2 mm to 2 mm, the entire surface of the negative electrode side current extraction layer 410 and/or the positive electrode side current extraction layer 416 can be discharged. can flow uniformly, and air bubbles 481 generated between the negative electrode current collector 411 and the negative electrode current extraction layer 410 and/or between the positive electrode current collector 415 and the positive electrode current extraction layer 416 are reliably eliminated. can be removed as soon as possible.

In addition, when the small holes 496 are formed in a slit shape, a It is preferable to form the slit relatively long enough to reliably remove the generated air bubble 481 .

Also, it is preferable that the plurality of small holes 496 are formed relatively more in the central portion than in the peripheral portion of the plane of the negative electrode side current extraction layer 410 and/or the positive electrode side current extraction layer 416 . The plurality of small holes 496 may be arranged evenly and regularly within the plane of the negative current extraction layer 410 and/or the positive current extraction layer 416 . However, since it tends to be difficult to remove the air bubbles 481 particularly in the central portion within the plane, by forming relatively more small holes 496 in the central portion than in the peripheral portion in the plane, the entire in-plane Air bubbles 481 can be more reliably removed over the entire time. Note that the above tendency becomes remarkable when a non-woven fabric made of carbon fiber or the like is used as the material for the negative current extraction layer 410 and the positive current extraction layer 416. It is particularly desirable to have relatively more at the central portion than at the inner peripheral portion.

As described above, in the secondary battery module, even if it is manufactured under the desired reduced pressure, it is difficult to remove air bubbles in the plane of the negative electrode side current extraction layer and/or the positive electrode side current extraction layer. For example, as described above, it is more difficult to remove air bubbles in the central portion of the plane than in the peripheral portion. Such a tendency is recognized as the size of the battery cell increases, and is particularly noticeable when the size of the battery cell is 20 cm×20 cm or more, or when the battery cell is flat and has a short axis length of 20 cm or more. In this embodiment, the present invention is applied to the battery cell 420 of this size, the small hole 496 is formed in the surface of the negative electrode side current extraction layer 410 and/or the positive electrode side current extraction layer 416, and furthermore, as described above. By devising the shape and arrangement of the holes 496, even if a large-sized air bubble 81 is generated in the plane of the negative electrode side current extraction layer 410 and/or the positive side current extraction layer 416 during manufacturing, the entire area of the plane can be prevented. Air bubbles 481 can be reliably removed over a period of time.

In the above-described embodiment, it has been described that local concentration of current can be suppressed by equalizing the resistances of the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 during discharge. The same is true during charging. During charging, the directions of the currents are all reversed, and the mechanism for equalizing the resistances of the negative current supply layer 410 and the positive current extraction layer 416 is the same as during discharging. Therefore, according to the present invention, local current concentration can be suppressed not only during discharging but also during charging, and the life of the battery can be further extended.

FIG. 24 shows an example in which a plurality of battery cells 20 share the negative current supply layer 410 and the positive current extraction layer 416 . In this example, a plurality of battery cells 420 are arranged between one negative current supply layer 410 and one positive current extraction layer 416 . In each battery cell 420, the negative electrode side current supply layer 410 and the positive electrode side current extraction layer 416 are commonly used. In the example of FIG. 24 as well, local current concentration can be suppressed in each battery cell 420 based on a similar mechanism.

It should be noted that in the case of configuring the assembled battery 450 as shown in FIG. 22, local concentration of current can be similarly suppressed by equalizing the resistances of the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 .

A positive temperature coefficient (PTC) thermistor (not shown) is interposed between the positive current collector 415 and the positive current extraction layer 416 and/or between the negative current collector 411 and the negative current supply layer 410. may be installed. This PTC thermistor may be made of a material such as an organic polymer in which conductive powder is dispersed.

The resistance of PTC thermistors is usually almost constant from room temperature to the Curie temperature, but increases sharply when the Curie temperature is exceeded. In this embodiment, by utilizing this characteristic, the resistance of the PTC thermistor is rapidly increased as the temperature rises, thereby equalizing the resistances of the negative current supply layer 410 and the positive current extraction layer 416, and locally current concentration can be suppressed.

In addition, if the portion where the current tends to concentrate or the portion where the current tends to disperse is known for the negative electrode-side current supply layer 410 and the positive electrode-side current extraction layer 416, a so-called functionally graded material (FGM: Functionally Graded Material) can be used for that portion. ) may be applied. Through this functionally graded material, the resistance value is changed continuously or stepwise within the material. By designing the material through this functionally gradient material, the negative electrode side current supply layer 410 has the function of dispersing the current more in the portion where the current tends to concentrate, and the function of concentrating the current in the portion where the current more easily disperses. and in the positive current extraction layer 416 .

[Second embodiment]
In addition to the configuration of the first embodiment described above, the aspect of the present invention may include the configuration of the second embodiment described below. The second embodiment will be described below. In the second embodiment, the same components and members as those in the first embodiment described above are given the same reference numerals, and the description thereof will be omitted.

In the secondary battery module 401 to which the present invention is applied, as shown in FIGS. there is As shown in FIG. 27, in which the battery cell 420 portion of the secondary battery module 401 is indicated by a dotted line, the negative electrode rectifying section 405 is formed in a rod shape, and the extending direction of the rod shape is substantially the lateral direction y. It is extended like this. By providing the rod-shaped negative electrode rectifying portion 5 , the negative electrode rectifying portion 5 is formed in a convex shape downward from the lower surface of the negative electrode current supply layer 410 below the negative electrode current collector 411 . . It is assumed that the negative rectifying section 405 is provided at one end in the longitudinal direction x perpendicular to the width direction y, but it is not limited to this. Further, the negative rectifying section 405 extends from one end side to the other end side in the width direction y, but is not limited to this, and extends from one end side and/or the other end side in the width direction y. It goes without saying that it may be configured such that it does not reach the side. The negative electrode rectifying section 405 is connected to a conductive section 407 made of a conductive layer for supplying current from an electric circuit during discharging, in other words, for sending electrons during discharging.

A positive electrode rectifying section 406 to which current is supplied extends in the width direction y (the depth direction in FIG. 19) in the positive electrode side current extraction layer 416 . As shown in FIG. 27, the positive electrode rectifying section 406 is formed in a bar shape and extends so that the extending direction of the bar shape is substantially the lateral direction y. By providing the rod-shaped positive rectifying section 406 , the positive rectifying section 406 is formed in a convex shape upward from the upper surface of the positive current extraction layer 416 above the positive current collector 415 . It is assumed that the positive rectifying section 406 is provided at one end in the longitudinal direction x perpendicular to the width direction y, but it is not limited to this. Also, the positive rectifying section 406 extends from one end side to the other end side in the width direction y, but it is not limited to this, and the one end side and/or the other end in the width direction y is extended. It goes without saying that it may be configured such that it does not reach the side. A conductive portion 408 made of a conductive layer is connected to the positive rectifying portion 406 to supply current to the electric circuit during discharge.

In the above-described embodiment, the positive rectifying section 406 is provided at one end in the longitudinal direction x, and the negative rectifying section 405 is provided at the other end in the longitudinal direction x, which is the opposite side. is exemplified. That is, the cross-sectional view as shown in FIG. 26 exemplifies the case where the positive rectifying section 406 and the negative rectifying section 405 are arranged diagonally, but it is not limited to this. Moreover, the negative rectification unit 405 and the positive rectification unit 406 are not necessarily limited to the case where both are mounted. good.

Materials constituting the negative electrode rectifying portion 405 and the positive electrode rectifying portion 406 are metal materials such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof, similarly to the negative electrode current collector 411 and the positive electrode current collector 415, and Examples include calcined carbon, conductive polymer materials, and conductive glass. At this time, the negative rectifying section 405 and the positive rectifying section 406 may be composed of a resin current collector made of a conductive polymer material. For example, a conductive polymer or a matrix resin to which a conductive filler made of a conductive filler is added may be used.

At this time, the negative rectifying section 405 is configured to have a lower resistance than the negative current supply layer 410 , and the positive rectifying section 406 is configured to have a lower resistance than the positive current extraction layer 416 . there is The adjustment of the resistance of the negative electrode rectifying section 405 relative to the negative electrode current supply layer 410 and the adjustment of the resistance of the positive electrode rectifying section 406 relative to the positive electrode current extraction layer 416 are realized through the selection of optimum materials. may

For example, when the material used for the negative current supply layer 410 is a metal material, the material forming the negative electrode rectifying section 405 has a lower resistance value than the metal material used for the negative current supply layer 410. A material having physical properties may be selected. Similarly, when the material used for the positive electrode current extraction layer 416 is a metal material, the material constituting the positive electrode rectifying section 406 has a higher resistance value than the metal material used for the positive electrode current extraction layer 416 . A material with low physical properties may be selected.

Further, when the material used for the negative rectifying section 405 and the negative current supply layer 410 is a resin current collector made of a conductive polymer material, the material constituting the negative rectifying section 405 is the negative current supply layer. The material of the conductive filler added to the resin current collector may be selected or the amount of the conductive filler added may be adjusted so that the resistance is lower than that of the layer 410 . Similarly, when the material used for the positive rectifying section 406 and the positive current extraction layer 416 is a resin current collector made of a conductive polymer material, the material forming the positive rectifying section 6 is The material of the conductive filler added to the resin current collector may be selected or the amount of the conductive filler added may be adjusted so that the resistance is lower than that of the extraction layer 416 .

The adjustment of the resistances of the negative electrode rectification unit 405 and the positive electrode rectification unit 406 can be realized by previously adjusting the shape that affects the resistance value, such as the cross-sectional area and length, in addition to the above-described method of selecting materials. can be For example, the positive rectifying section 406 shown in FIG. adjusted to be lower.

Next, the operation of the secondary battery module 401 to which the aspect of the present invention is applied will be explained. FIG. 28 shows the paths through which the currents P to S flow when the secondary battery module 401 is composed of single cells, in other words, the paths along which electrons move.

When an external load (not shown) of the secondary battery module is connected between the positive electrode 403 and the negative electrode 402 during discharge, electrons reaching the negative electrode current collector 411 from the negative electrode active material layer 412 are transferred to the negative electrode current collector. It propagates toward the negative electrode rectifying section 405 on the negative electrode side current supply layer 410 in contact with the body 411 . Then, the electrons pass through an external load, reach the positive electrode rectifying section 406 in the positive electrode 403 , and propagate on the positive electrode side current extraction layer 416 from there. At this time, it is self-evident that electrons trying to propagate on the negative electrode current supply layer 410 toward the negative electrode rectifying section 405 try to move in the shortest possible distance. It is natural for the propagation path of to take a linear movement path parallel to the longitudinal direction x. Similarly, it is self-evident that electrons trying to propagate from the positive electrode rectifying section 406 on the positive current extraction layer 416 try to move in the shortest possible distance. Naturally, the path is parallel to the longitudinal direction x and linear. In other words, this electron propagation path can be considered as a current flow path. The path through which this current flows is parallel to the longitudinal direction x and linear on the positive electrode-side current extraction layer 416, and is also parallel to the longitudinal direction x on the negative electrode-side current supply layer 410. And it becomes natural that it becomes linear.

In addition, during discharge, the lithium ions occluded in the negative electrode active material 441 move toward the positive electrode active material 442 . Since it is obvious that the lithium ions try to move toward the positive electrode active material 442 in the shortest possible distance, the movement path is perpendicular to the longitudinal direction x and parallel to the thickness direction z. , and linear.

Under the premise of such current flow and lithium ion movement path, the positive electrode rectifying section 406 extends in the width direction y in the positive electrode side current extraction layer 416 . As a result, as shown in FIG. 28, various currents P to S flow in the negative electrode rectifying section 405. All of these flow straight through the positive electrode side current extraction layer 416 in a direction parallel to the longitudinal direction x. By doing so, it is taken in by the positive electrode rectifying section 406 . When the positive rectifying section 406 is not extended in the width direction y, the paths through which all the currents P to S flow on the positive electrode side current extraction layer 416 are not straight, but oblique. The current propagation path becomes longer. On the other hand, according to the aspect of the present invention, since the positive electrode rectifying section 406 extending in the width direction y is disposed on one end side in the longitudinal direction, the flow from each location in the width direction y The incoming currents P to S reach the positive rectifying section 406 by naturally traveling straight in the longitudinal direction x. As a result, the currents P to S do not take oblique paths on the positive electrode-side current extraction layer 416, but go straight in the longitudinal direction x, and are extracted to the positive electrode rectifying section 406 along the shortest route. becomes. In particular, by configuring the positive electrode rectifying section 406 to have a resistance lower than that of the positive electrode side current extraction layer 416 , the current flowing on the positive electrode side current extraction layer 416 flows smoothly toward the positive electrode rectifying section 6 .

As a result, as shown in FIG. 28, the flow path of all the currents P to S and the movement of lithium ions from the negative electrode rectifying section 405 in the negative electrode side current supply layer 410 are parallel to the longitudinal direction x and linear. From there, lithium ions move from the negative electrode 402 toward the positive electrode 403 in a direction parallel to the thickness direction z and in a straight line, and further inside the positive electrode side current extraction layer 416 to the positive electrode rectifying section 6. Currents P to S flow linearly in a direction parallel to the longitudinal direction x. The flow path of the currents P to S in the negative electrode current supply layer 410 and the direction of movement of the lithium ions, and the direction of movement of the lithium ions and the flow path of the currents P to S in the positive electrode current extraction layer 416 are substantially perpendicular to each other. becomes.

That is, according to the aspect of the present invention, since the positive rectifying section 406 extends in the width direction y, the path from the negative rectifying section 405 to the positive rectifying section 406 through which all the currents P to S flow is shortest distance. As a result, the paths through which the currents P to S flow in the negative current supply layer 410 and the positive current extraction layer 416 are shortened, so that the resistance can be reduced. In addition to this, the paths of the currents P to S flowing through the negative current supply layer 410 and the positive current extraction layer 416 are all parallel to the longitudinal direction x, and the propagation distances are equal. The uniformity of the resistance in the supply layer 410 and the positive current extraction layer 416 can be achieved. As a result, according to the aspect of the present invention, a current can flow uniformly without generating a local resistance distribution on the negative current supply layer 410 and the positive current extraction layer 416 . As a result, there are no areas where a large amount of current flows locally, the temperature does not rise locally in those areas, and a large current easily flows locally without a local decrease in resistance. You can avoid falling into a vicious circle. In this way, a large current does not flow locally on the negative current supply layer 410 and the positive current extraction layer 416, and the current distribution can be made uniform, thereby suppressing deterioration of the battery cell 420 itself. can be achieved, and by extension the life of the battery cell 420 can be increased.

Although the negative electrode rectifying portion 405 is not an essential component in the present invention, it is extended in the width direction y so that the current is dispersed in the width direction y before the negative electrode side current supply layer 410 . can be propagated upwards. Therefore, in the present invention having the positive rectifying section 406 extending in the width direction y, by extending the negative rectifying section 405 also in the width direction y, the paths of the respective currents are arranged in the longitudinal direction. The current can flow parallel to x, which is more suitable for uniform current distribution.

At this time, both the positive rectifying section 406 and the negative rectifying section 405 may extend from one end side to the other end side in the width direction y. As a result, the current can be dispersed over the entire length in the width direction y on the side of the negative rectification section 405 , and the dispersed current is allowed to travel straight in parallel to the longitudinal direction x, so that all of these are transferred to the positive rectification section 406 . It becomes possible to take out at As a result, by dispersing the current more and lowering the resistance value, local concentration of the current can be further suppressed. Note that it is not essential that both the positive rectifying section 406 and the negative rectifying section 405 extend from one end side to the other end side in the width direction y, and either the positive rectifying section 406 or the negative rectifying section 405 It may extend from one end side to the other end side in the width direction y. It goes without saying that both the positive rectifying section 406 and the negative rectifying section 405 may not reach the one end side and the other end side in the width direction y.

The positive electrode rectifying section 406 is provided on one end side in the longitudinal direction x, and the negative electrode rectifying section 405 is provided on the other end side in the longitudinal direction x. 403 and the negative electrode 402 can be effectively used for discharging.

FIG. 29 shows a secondary battery module 401' according to another embodiment to which aspects of the present invention are applied. In the secondary battery module 401', the same constituent elements and members as those of the above-described secondary battery module 401 are denoted by the same reference numerals, and descriptions thereof are omitted below.

The secondary battery module 401' is similar to the secondary battery module 401 in that it has the battery cells 420 described above. However, in this secondary battery module 401', the positive rectifying section 406 and the negative rectifying section 405 extend in the longitudinal direction x. A conductive portion 408 for supplying current to the electric circuit is connected to the positive rectifying portion 406 , and a conductive portion 407 is connected to the negative rectifying portion 405 .

In such a secondary battery module 401', when an external load (not shown in the secondary battery module) is connected between the positive electrode 403 and the negative electrode 402 during discharging, the path through which the current flows is the positive electrode side current extraction layer. 416 , it is parallel to the width direction y and linear, and similarly on the negative electrode side current supply layer 410 , it is natural to be parallel to the width direction y and linear. Also, the lithium ions occluded in the negative electrode active material 441 move toward the positive electrode active material 442 . Since it is obvious that the lithium ions try to move toward the positive electrode active material 442 in the shortest possible distance, they are linear and parallel to the thickness direction z.

Under the premise of such current flow and lithium ion movement path, the positive electrode rectifying section 406 extends in the longitudinal direction x in the positive electrode side current extraction layer 416 . As a result, as shown in FIG. 29, various currents T to V flow in the negative electrode rectifying section 405. All of these flow through the positive electrode side current extraction layer 416 in a direction parallel to the width direction y and in a straight line. By going straight, it is taken in by the positive electrode rectifying section 406 . That is, the currents T to V flowing from each location in the longitudinal direction x naturally travel straight in the width direction y and reach the positive rectifying section 406 . As a result, the currents T to V do not take oblique paths on the positive electrode-side current extraction layer 416, but go straight in the width direction y, and are extracted to the positive electrode rectifying section 406 along the shortest route. It will happen.

That is, according to the aspect of the present invention, since the positive rectifying section 406 extends in the longitudinal direction x, the path from the negative rectifying section 405 to the positive rectifying section 406, through which all the currents T to V flow, is the shortest. be the distance. As a result, the paths through which the currents T to V flow in the negative current supply layer 410 and the positive current extraction layer 416 are shortened, and the propagation distances are made equal, so that the resistance can be reduced and uniformed. As a result, a current can flow uniformly without generating a local resistance distribution on the negative electrode current supply layer 410 and the positive electrode current extraction layer 416, and the temperature does not rise locally. It is possible to prevent a vicious circle in which a large current tends to flow locally without causing a dramatic decrease in resistance.

Furthermore, according to the secondary battery module 401', the positive rectifying section 406 and the negative rectifying section 405 are extended in the longitudinal direction x, so that the current flows in the width direction y. Since the lateral direction y is shorter than the longitudinal direction x, the distance through which the current flows can be shortened. Since the resistance decreases as the distance through which the current flows becomes shorter, it is possible to increase the effect of lowering the resistance and making it uniform. Therefore, according to the secondary battery module 401', the deterioration of the battery cells 420 themselves can be further suppressed, and the life of the battery cells 420 can be extended more preferably.

Similarly, in the secondary battery module 401', either one or both of the positive rectifying section 406 and the negative rectifying section 405 may extend from one end side to the other end side in the longitudinal direction y. As a result, the current can be dispersed over the entire length in the longitudinal direction x on the side of the negative rectifying section 405 , and the dispersed current is allowed to travel straight in parallel to the lateral direction y, so that all of these are transferred to the positive rectifying section 406 . It becomes possible to take out at As a result, by dispersing the current more and lowering the resistance value, local concentration of the current can be further suppressed. In addition, the positive rectification section 406 is provided on one end side in the width direction y, and the negative rectification section 405 is provided on the other end side in the width direction y. It is possible to effectively utilize the positive electrode 403 and the negative electrode 402 in the discharge.

In the above-described embodiment, it has been described that local concentration of current can be suppressed by equalizing the resistances of the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 during discharge. The same is true during charging. During charging, the directions of the currents are all reversed, and the mechanism for equalizing the resistances of the negative current supply layer 410 and the positive current extraction layer 416 is the same as during discharging. Therefore, according to the aspect of the present invention, local concentration of current can be suppressed not only during discharging but also during charging, and the life of the battery can be further extended.

By adding the configuration of the second embodiment to the configuration of the first embodiment in this way, it is a matter of course that the above-described effects can be enhanced. As a specific example, in the present embodiment, small holes 496 may be formed in the negative current extraction layer 410 and/or the positive current extraction layer 416 as in the first embodiment. As a result, local concentration of current can be suppressed during discharging and charging, and the life of the battery can be further extended. When air bubbles 481 are formed between them, the air in the air bubbles 481 passes through the small holes 496 and is released to the outside by putting in a reduced pressure environment, so that the air bubbles 481 can be removed.

[Third embodiment]
In the aspect of the present invention, in addition to the configuration of the first embodiment described above, the configuration of the third embodiment described below may be included. In the third embodiment, the same components and members as those in the above-described first and second embodiments are denoted by the same reference numerals, and descriptions thereof are omitted below.

In the third embodiment, as shown in FIG. 30, in the positive electrode side current extraction layer 416, in other words, on the upper surface of the positive electrode current collector 415, a plurality of current extraction portions 436 as conductors and a positive electrode conductive wire 422 are provided. , a positive junction 426 is mounted.

FIG. 31 is a plan view of the positive electrode side current extraction layer 416 viewed from above. In the positive electrode side current extraction layer 416, in other words, a plurality of current extraction portions 436a to 436d are connected to the upper surface of the positive electrode current collector 415 as conductors. The current extracting portions 436a to 436d are electrically connected to the positive electrode current collector 415. As shown in FIG. The positive current extraction layer 416 also includes a plurality of positive conductive wires 422 a to 422 d for electrically connecting the current extraction portions 436 a to 436 d to the positive junction 426 . The lengths from the current extraction portions 436a to 436d of the positive electrode conductors 422a to 422d to the positive electrode junction portion 426 are substantially the same. The term “substantially the same” as used herein is not limited to the case where the lengths are completely the same, and the total length may have a difference of about 20%. The positive current extraction layer 416 is divided into a plurality of regions 432a to 432d whose top surfaces are substantially uniform. The term "substantially uniform" as used herein refers to the case where the regions 432a to 432d are completely symmetrical in shape and have the same area. The shape of 432d may deviate slightly from perfect symmetry, and an error may occur in the area between regions 432a-432d.

These areas 432a to 432d do not need to consist of areas that are clearly physically separated, and may be areas that are not physically separated and are separated beyond what they appear to be. The term "apparent division" as used herein means a division allocated in design, that is, although it is divided as a region on the design drawing, it is actually a single positive electrode side current extraction layer 416 that has no division as a whole. It may be configured. Also, the regions 432a to 432d may be composed of physically distinct regions. In such a case, the positive current extraction layer 416 is separated by an insulator or the like so as to form mutually independent regions 432a to 432d. When the positive electrode-side current extraction layer 416 is physically divided into a plurality of regions 432a to 432d, not only the positive electrode-side current extraction layer 416 but also the negative electrode current collector 411, the negative electrode active material layer 412, and the separator that constitute the battery cell 420. 413 and the positive electrode active material layer 414 may be similarly separated via an insulator or the like.

In the example of FIG. 31, the regions 432a to 432d are formed by equally dividing the positive electrode side current extraction layer 416, which is square in plan view, into four parts, and are exactly square in plan view. However, the regions 432a to 432d are not limited to having such a shape, and if the positive electrode side current extraction layer 416 is rectangular in plan view, it can be It may be configured in a rectangular shape divided into four.

In the example of FIG. 31, the case where the positive electrode side current extraction layer 416 is divided into four regions 432a to 432d has been described as an example, but the present invention is not limited to this, and any number of regions can be used as long as there is a plurality of regions. It may be configured by being divided. Even in such a case, it is assumed that the regions 432 are configured to be equal to each other. It may be understood that there is. Also, the respective regions are not limited to a completely equal relationship, and may be approximately equal (substantially equal).

The current extraction portions 436a-436d are provided substantially at the center of the above-described regions 432a-432d. Moreover, the positive electrode junction part 426 is located at the center of the positive electrode current collector 415 composed of the regions 432a to 432d, and is provided at a junction where the boundaries of the regions 432a to 432d intersect each other at one point. In the example of FIG. 31, positive electrode conductive wires 422a to 422d extend linearly from current extraction portions 436a to 436d provided substantially at the center of regions 432a to 432d toward this positive electrode junction portion 426. In the example of FIG. That is, the positive electrode conductors 422a to 422d are linearly extended from the current extraction portions 436a to 436d provided substantially at the center of the regions 432a to 432d provided evenly to each other toward the positive electrode junction portion 426. , it is obvious that the lengths are geometrically the same. In this way, the lengths of the positive electrode conductors 422a-422d are designed to be the same as each other, but they are not necessarily exactly the same, and there may be some length deviation between the positive electrode conductors 422a-422d. is acceptable. A conductive portion 408 made of a conductive layer for supplying current to the electric circuit during discharge is connected from the positive junction portion 426 .

It should be noted that it is not essential that the positive electrode junction 426 be formed at the center of the positive electrode current collector 415 composed of the regions 432a to 432d. For example, as shown in FIG. It may be Even in such a case, the lengths of the positive electrode conductors 322a to 322d are adjusted as shown in FIG. 32 so that the lengths from the current extraction portions 436a to 436d to the positive electrode junction portion 426 are substantially the same. It will happen.

In the present embodiment, the wiring composed of the current extraction portions 436a to 436d, the positive electrode conductors 322a to 322d, and the positive electrode junction portion 426 is not essential, and at least the wiring provided with the current extraction portion 436 may be used. good. At this time, the current extraction part 436 is configured to pass through the positive electrode current extraction layer 416 from the upper end to the lower end, which is convenient when another circuit is connected to the upper part of the positive electrode current extraction layer 416. can be increased.

The negative electrode-side current supply layer 410 is formed on the lower surface of the negative electrode current collector 411 as shown in FIG. 33, and is composed of an insulator. In the negative current supply layer 410, in other words, a plurality of current supply parts 435a to 435d as conductors are connected to the lower surface of the negative current collector 411. FIG. The current supply parts 435 a to 435 d are electrically connected to the negative electrode current collector 411 .

The negative electrode-side current supply layer 410 includes a plurality of negative electrode conductive lines 421a to 321d for electrically connecting the current supply portions 435a to 435d to the negative electrode junction portion 425. The lengths from the current supply portions 435a to 435d of the negative electrode conductive lines 421a to 321d to the negative electrode junction portion 425 are substantially the same. Similarly to the positive electrode current extraction layer 416, the negative electrode current supply layer 410 also has a lower surface divided into a plurality of regions 431a to 431d that are substantially equal to each other. Details of the regions 431a to 431d are the same as those of the regions 432a to 432d described above.

The current supply parts 435a to 435d are provided substantially in the center of the above-described regions 431a to 431d. The negative junction 425 is located at the center of the negative current supply layer 410 consisting of the regions 431a to 431d, and is provided at a junction where the boundaries of the regions 431a to 431d intersect at one point. That is, the negative electrode conductive lines 421a to 421d are linearly extended from the current supply portions 435a to 435d provided approximately at the center of the regions 431a to 431d which are evenly provided to each other toward the negative electrode junction portion 425. , it is obvious that the lengths are geometrically the same. In this way, the lengths of the negative electrode conductors 421a to 421d are designed to be the same as each other, but they do not necessarily have to be exactly the same. is acceptable. A conductive portion 7 made of a conductive layer to which current is supplied from an electric circuit during discharge is connected to the negative electrode junction portion 425 .

It should be noted that it is not essential that the negative electrode junction 425 is formed at the center of the negative electrode current supply layer 410 composed of the regions 431a to 431d, and is formed at a location other than the center of the negative electrode current supply layer 410. may Even in such a case, the negative electrode conductive lines 421a to 421d need to be adjusted so that the lengths from the current supply portions 435a to 435d to the negative electrode junction portion 25 are substantially the same.

In the present embodiment, the wiring consisting of the current supply portions 435a to 435d, the negative electrode conductive wires 421a to 421d, and the negative electrode junction portion 425 is not essential, and at least the wiring provided with the current supply portion 435 may be used. good. At this time, the current supply portion 435 is configured to penetrate the negative electrode current supply layer 410 from the upper end to the lower end, which is convenient when another circuit is connected to the lower portion of the negative electrode current supply layer 410. can be increased.

Next, the operation of the third embodiment will be explained.

When an external load (not shown) of the secondary battery module 401 is connected between the positive electrode 403 and the negative electrode 402 during discharge, the current in each of the regions 432a to 432d in the positive electrode current extraction layer 416 is is taken out by a current take-out portion 436 provided at the center. That is, the currents are dispersed in each of the regions 432 a to 432 d and extracted to the current extracting portion 436 , and the extracted currents are dispersed and flow through the positive electrode conductors 422 to be sent to the positive electrode junction portion 426 . Similarly, the current flowing into the negative electrode junction portion 425 is dispersed and branched to each negative electrode conductive line 421 to reach the current supply portion 435 .

Similarly, in the negative electrode, the current from the external circuit flows into the negative electrode confluence portion 425 and is dispersed in each negative electrode conductive line 421 from here to reach the current supply portion 435 . Since the current supply unit 435 is provided for each of the regions 431a to 431d, the current can be supplied to the regions 431a to 431d. As a result, the current flowing through the negative electrode current collector 411 can be distributed without being concentrated in one pole.

As a result, the current supplied to the negative electrode current collector 411 and the current taken out from the positive electrode current collector 415 can be distributed without being concentrated in the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 . As a result, the current flowing through each negative electrode conductive line 421 and each positive electrode conductive line 422 can be decreased, and the resistance can be decreased. In addition to this, the paths of the currents flowing through the negative electrode current supply layer 410 and the positive electrode current extraction layer 416 via the negative electrode conductive wires 421 and the positive electrode conductive wires 422 have the same propagation distance. Uniform resistance can be achieved in the current supply layer 410 and the positive current extraction layer 416 . As a result, according to the present invention, a current can flow uniformly without generating a local resistance distribution on the negative current supply layer 410 and the positive current extraction layer 416 . As a result, there are no areas where a large amount of current flows locally, the temperature does not rise locally in those areas, and a large current easily flows locally without a local decrease in resistance. You can avoid falling into a vicious circle. In this way, a large current does not flow locally on the negative current supply layer 410 and the positive current extraction layer 416, and the current distribution can be made uniform, thereby suppressing deterioration of the battery cell 420 itself. can be achieved, and by extension the life of the battery cell 420 can be increased.

As described above, the aspect of the present invention includes, on the positive electrode side, a plurality of positive electrode conductor wires 422 for electrically connecting from each current extraction portion 436 to the positive electrode junction portion 426, and the positive electrode conductor wires 422 are The lengths are substantially the same as each other. In particular, the current extraction portions 436 are provided at approximately equal positions in the positive electrode side current extraction layer 416 . As a result, the current to be taken out from the positive electrode side current extraction layer 416 can be taken out more evenly between the plurality of current extraction portions 436, and the current can be distributed and distributed to the plurality of positive electrode conductive wires 422. This eliminates the occurrence of a portion where a large amount of current locally flows. At this time, the positive current extraction layer 416 is divided into a plurality of regions 432 that are substantially equal to each other, and each current extraction part 436 is provided substantially at the center of each region 432, so that the positive current extraction layer 416 It becomes possible to more evenly extract the current to be extracted among the plurality of current extracting portions 436 .

Similarly, on the negative electrode side, a plurality of negative electrode conductive wires 421 are provided for electrically connecting each current supply portion 35 to a negative electrode junction portion 425, and the lengths of the negative electrode conductive wires 421 are substantially equal to each other. assumed to be the same. In particular, the current supply portions 435 are provided at substantially equal positions on the negative electrode side current supply layer 410 . As a result, the current to be supplied to the negative electrode current collector 411 can be more uniformly supplied among the plurality of current supply portions 435, and the current supply portion 435 is provided with a plurality of negative electrode conductive wires. 421 can be dispersively flowed, and there is no occurrence of a portion where a large amount of current flows locally. At this time, the negative electrode-side current supply layer 410 is divided into a plurality of regions 431 that are substantially equal to each other, and each current supply portion 435 is provided substantially at the center of each region 431, so that the negative electrode current collector 411 is It becomes possible to more evenly supply the current to be supplied between the plurality of current supply units 435 .

The positive current extraction layer 416 and the current extraction part 406, the positive conductive wire 422, and the positive junction part 426 included in the positive current extraction layer 416 may be classified in function like a so-called printed circuit board. That is, the positive current extraction layer 416 may be made of an insulator on the printed circuit board, and the current extraction part 406, the positive conductive wire 422, and the positive junction part 426 may be configured as wiring on the printed circuit board.

The functions of the negative current supply layer 410 and the current supply section 405, the negative conductive line 421, and the negative junction 425 included in the negative current supply layer 410 may be classified like a so-called printed circuit board. That is, the negative current supply layer 410 may be made of an insulator on the printed circuit board, and the current supply part 405, the negative conductive line 421, and the negative junction 425 may be made of wiring on the printed circuit board.

When the positive electrode side current extraction layer 416 and the negative electrode side current supply layer 410 are composed of an insulator on a printed circuit board, the material thereof may be a paper substrate impregnated with phenol resin, or a paper substrate impregnated with epoxy resin. impregnated material, glass fabric (woven glass fiber) impregnated with epoxy resin, paper base material impregnated with polyimide resin, glass cloth base material It may be composed of materials impregnated with fluororesin, glass cloth substrate impregnated with PPO (Poly Phenylene Oxide) resin, metal-based substrates such as aluminum, or glass-ceramic based substrates. It may be configured with a substrate that has

By classifying the functions like the printed circuit board, it is possible to reduce the contact resistance when connecting directly to other circuits or printed circuit boards (not shown). In addition, by actually forming the positive electrode current extraction layer 416 and the negative electrode current supply layer 410 with a hard printed circuit board, the current supply portion 405, the negative electrode conductive wire 421, the negative junction portion 425, the current supply portion 405, and the negative electrode conductive layer are formed. The easiness of the work can be improved in providing the wiring consisting of the line 421 and the negative electrode confluence portion 425 . As a result, it is possible to enhance the convenience in providing the wiring described above.

In this way, by adding the configuration of the third embodiment to the configuration of the first embodiment, it is a matter of course that the above-described effects can be enhanced. As a specific example, in the present embodiment, small holes 496 may be formed in the negative current extraction layer 410 and/or the positive current extraction layer 416 as in the first embodiment. In this case, each small hole 496 is formed in a portion where the current extraction portion 436, the positive electrode conductive wire 422, and the positive electrode junction portion 426 are not formed in the plane of the negative electrode side current extraction layer 410 and/or the positive electrode side current extraction layer 416. As a result, a large current does not flow locally on the negative current supply layer 410 and the positive current extraction layer 416, and the current distribution can be made uniform. Deterioration can be suppressed, and eventually the life of the battery cell 420 can be extended. The air in the air bubbles 481 passes through the small holes 496 and is discharged to the outside by placing in a reduced pressure environment, so that the air bubbles 481 can be removed.

A secondary battery module according to an embodiment of the present invention is a laminated battery obtained by laminating a plurality of storage elements each having a negative electrode current collector, a negative electrode active material layer, a separator or a solid electrolyte, a positive electrode active material layer, and a positive electrode current collector. A current extraction layer is in contact with at least one surface of the outermost layer in the laminated battery, and a small hole penetrating vertically is formed in the current extraction layer.

In the above one embodiment, the small holes are circular, elliptical, or slit-shaped in plan view.

In the above embodiment, when the small hole is elliptical, the dimension of the minor axis of the elliptical shape is 0.2 mm to 2 mm, and when the small hole is circular, the radius of the circular shape is 0.2 mm to 2 mm.

In the above embodiment, a plurality of small holes are formed in the current extraction layer, and relatively more small holes are formed in the central portion of the current extraction layer than in the peripheral portion of the current extraction layer.

In the above embodiment, the current extraction layer includes a positive electrode current extraction layer and a negative electrode current supply layer, and the positive electrode current extraction layer and the negative electrode current supply layer are made of elastically deformable elastic material. ing.

In the above embodiment, the current extraction layer is made of nonwoven fabric.

In the above embodiment, a PTC thermistor is interposed between the positive current collector and the positive current extraction layer.

In the above embodiment, a PTC thermistor is interposed between the negative electrode current collector and the negative electrode current supply layer.

In the above embodiment, the positive electrode-side current extraction layer includes a plurality of current extraction portions and a plurality of positive electrode conductive wires for electrically connecting the current extraction portions to the positive electrode merging portion. The length of each positive electrode conductive wire is substantially the same as each other.

In the above embodiment, above the positive electrode current collector, the positive electrode rectifying section that delivers current during discharge extends in the width direction.

According to the aspects of the invention described above, it is possible to realize a battery module that can be easily assembled by simplifying the internal configuration and sealing the assembled battery with the exterior body.

Claims

A positive electrode current collector including a resin current collector layer; a positive electrode having a positive electrode active material layer including a positive electrode active material formed on the positive electrode current collector; a negative electrode current collector including a resin current collector layer; A plurality of unit cells are stacked each including a negative electrode having a negative electrode active material layer containing a negative electrode active material formed on a current collector, and a separator disposed between the positive electrode active material layer and the negative electrode active material layer. an assembled battery,
a plurality of light emitting units provided for each of the cells and transmitting optical signals based on the state of the cells;
a gas barrier film covering the assembled battery;
and
The battery module, wherein the gas barrier film as a whole is transparent to the optical signal.
The battery module according to claim 1, wherein the light emitting section transmits the optical signal to the outside through the gas barrier film.
3. The battery module according to claim 1, wherein a light guide tube is provided outside the gas barrier film to cover the plurality of light-emitting portions via the gas barrier film.
4. The battery module according to claim 3, wherein a light-receiving section for receiving a plurality of said optical signals propagating inside said light guide tube is provided outside said gas barrier film.
3. The battery module according to claim 1 or 2, wherein a light-receiving section that directly receives the optical signal transmitted from the light-emitting section via the gas barrier film is provided outside the gas barrier film.
6. The gas barrier film according to any one of claims 1 to 5, wherein a light shielding layer for shielding the optical signal is provided on a part of the surface of the gas barrier film, and the light shielding layer is not provided on a position corresponding to the light emitting portion on the surface. The battery module according to any one of items 1 and 2.
7. The battery module according to claim 6, wherein the surface of said gas barrier film is covered with said light shielding layer except for a portion aligned with the region containing said plurality of light emitting portions.
7. The battery module according to claim 6, wherein the surface of the gas barrier film is covered with the light shielding layer except for the portions aligned with the light emitting portions.
A method for manufacturing the battery module according to any one of claims 1 to 8,
a step of sequentially forming a plurality of concave portions by thermoforming on the surface of a strip-shaped first gas barrier film that becomes the gas barrier film that is transparent to the optical signal as a whole;
a step of sequentially fitting a structure including the assembled battery and a plurality of light-emitting portions provided for each of the cells into the recess;
laminating a strip-shaped second gas barrier film on the first gas barrier film to sequentially seal a plurality of the structures;
a step of cutting the first gas barrier film and the second gas barrier film for each structure;
A method for manufacturing a battery module, comprising:
The strip-shaped first gas barrier film provided for the step of forming the recesses is covered with the light shielding layer except for a portion aligned with the region including the plurality of light emitting portions,
10. The method of manufacturing a battery module according to claim 9, wherein when the concave portion is formed in the strip-shaped first gas barrier film, the portion is positioned on a side surface of the concave portion.
The strip-shaped first gas barrier film used in the step of forming the recesses is covered with the light shielding layer except for a portion aligned with each light emitting portion,
10. The method of manufacturing a battery module according to claim 9, wherein when the concave portion is formed in the strip-shaped first gas barrier film, the portion is positioned on a side surface of the concave portion.
A current extraction layer is in contact with at least one surface of the outermost layer of the cell,
A small hole penetrating vertically is formed in the current extraction layer,
The battery module according to any one of claims 1 to 8.
The small holes are either circular, elliptical, or slit-shaped in plan view,
The battery module according to claim 12.
When the small hole has an elliptical shape, the dimension of the minor axis of the elliptical shape is 0.2 mm to 2 mm,
When the small hole is circular, the radius of the circular shape is 0.2 mm to 2 mm.
The battery module according to claim 12 or 13.
A plurality of the small holes are formed in the current extraction layer, and relatively more small holes are formed in the central portion of the current extraction layer than in the peripheral portion of the current extraction layer.
The battery module according to any one of claims 12 to 14.
The current extraction layer includes a positive current extraction layer and a negative current supply layer,
The positive electrode-side current extraction layer and the negative electrode-side current supply layer are made of an elastic material that is elastically deformable,
The battery module according to any one of claims 12-15.
wherein the current extraction layer is made of a non-woven fabric,
The battery module according to any one of claims 12-16.
A PTC thermistor is interposed between the positive current collector and the positive current extraction layer.
The battery module according to any one of claims 12-17.
A PTC thermistor is interposed between the negative electrode current collector and the negative electrode current supply layer.
The battery module according to any one of claims 12-18.
The positive electrode-side current extraction layer includes a plurality of current extraction portions and a plurality of positive electrode conductive wires for electrically connecting each of the current extraction portions to the positive electrode confluence portion. are substantially identical to each other,
The battery module according to claim 18 or 19.
Above the positive electrode current collector, a positive electrode rectifying section that delivers current during discharge extends in the width direction.
The battery module according to any one of claims 12-20.