JP2018147837A - Energy storage device and energy storage apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy storage device which is easy to assemble or replace.SOLUTION: An energy storage device according to an aspect of the present invention includes: a case which is formed of a flexible sheet and in which the flexible sheet is joined in an overlapping manner at least at a portion of a peripheral portion of the flexible sheet; an energy storage element which comprises a positive electrode plate and a negative electrode plate accommodated in the case, and a pair of current collectors extending from the positive electrode plate and the negative electrode plate to the outside through the joined portion of the case; and a pair of connecting members which is connected to the current collectors outside the case. The connecting members have a pair of contact surfaces disposed with a distance larger than a largest thickness of the case on both sides of the joined portion of the sheet in a sheet thickness direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage element and a power storage device.

  For example, a power storage device having a relatively large capacity that is used as a power source for an automobile or the like is often configured by electrically connecting a plurality of power storage elements (cells). As the structure of the power storage element of such a power storage device, the electrode body is sealed in a bag-like case in which the peripheral portions of the flexible sheet are joined, and a thin plate-like conductor extending from the electrode body is externally connected to the sheet joint. In many cases, the structure drawn out is used.

  In such an electrical connection structure between power storage elements, a conductive connection member is joined to a conductor extending from the joint of the sheet, and the connection members of adjacent power storage elements are electrically connected. For example, Japanese Patent Laying-Open No. 2015-56341 describes that adjacent connecting members are connected by cold welding, ultrasonic welding, laser welding, or the like.

Japanese Patent Laying-Open No. 2015-56341

  In the configuration of the power storage device described in the above publication, assembling is complicated because it takes time to connect the connection members. Further, in the configuration of the power storage device described in the above publication, the work of exchanging some power storage elements is also complicated.

  In view of the above problems, an object of the present invention is to provide a power storage element and a power storage device that can be easily assembled and replaced.

  A power storage element according to one embodiment of the present invention is formed of a flexible sheet, and a case in which the flexible sheet is overlapped and bonded at least at a part of the peripheral portion; a positive electrode plate accommodated in the case; A negative electrode plate, a power storage element having a pair of current collectors extending from the positive electrode plate and the negative electrode plate to the outside through the joint portion of the case, and a pair of connecting members connected to the current collector outside the case And the connection member has a pair of contact surfaces arranged at intervals larger than the maximum thickness of the case on both sides in the sheet thickness direction at the joint portion of the sheet.

  In the energy storage device according to one embodiment of the present invention, the connection member is adjacent to each other because the connection member has a pair of contact surfaces arranged at intervals larger than the maximum thickness of the case on both sides in the sheet thickness direction of the joint portion of the sheet. A plurality of power storage elements can be electrically connected by stacking the contact surfaces of the connection members of the power storage elements so as to contact each other and sandwiching the plurality of stacked connection members in the stacking direction. Therefore, the power storage element according to one embodiment of the present invention is relatively easy to assemble and replace.

It is typical sectional drawing which shows the electrical storage apparatus of one Embodiment of this invention. FIG. 2 is a schematic plan view of the electricity storage device of FIG. 1. FIG. 2 is a schematic plan view of a power storage device according to an embodiment different from FIG. 1 of the present invention. FIG. 4 is a schematic plan view of a power storage device according to an embodiment different from FIGS. 1 and 3 of the present invention. It is typical sectional drawing of the electrical storage element of embodiment different from FIG.1, FIG3 and FIG.4 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[First embodiment]
The power storage device according to the first embodiment of the present invention shown in FIG. 1 includes a plurality of power storage elements 1 each of which is another embodiment of the present invention, and a holding body 2 that holds the plurality of power storage elements 1. . The power storage device further includes a cooling member 3 that contacts the plurality of power storage elements 1 and removes heat from the power storage elements 1.

[Storage element]
The power storage element 1 is formed of a flexible sheet 4, and a case 5 in which the sheets 4 are overlapped and joined at at least a part of the peripheral edge, a positive electrode plate 6, a negative electrode plate 7, and A power storage element 11 having a stack of separators 8 and a pair of current collectors (positive electrode current collector 9 and negative electrode current collector 10) extending from the positive electrode plate 6 and the negative electrode plate 7 through the joint portion of the case 5; A pair of connection members (a positive electrode connection member 12 and a negative electrode connection member 13) connected to the current collectors 9 and 10 outside the case 5 are provided.

  In the power storage device, the plurality of power storage elements 1 are arranged so that the positive and negative directions of the power storage elements 11 are alternately switched, and the connection members 12 and 13 are brought into contact with each other. In addition, the power storage device further includes plate-shaped or sheet-shaped insulating members 14 that are disposed alternately between the connection members 12 and 13 of the adjacent power storage elements 1. Thereby, the some electrical storage element 1 is electrically connected in series.

<Case>
The case 5 is formed of two sheets 4, one folded sheet 4, or one sheet 4 wound in a cylindrical shape, and a positive plate 6 is formed inside by joining the opposing sheets 4. The laminate of the negative electrode plate 7 and the separator 8 and the electrolyte are enclosed. That is, the case 5 includes a four-side sealed bag in which the sheet 4 is bonded at the four peripheral edges, a three-side sealed bag in which the other peripheral edge of the sheet 4 folded at one peripheral edge is bonded, or a sheet. It can be set as the pillow-type bag which joined 4 to the cylinder shape and joined the peripheral part of the both ends of a cylindrical body. In the present embodiment, as shown in FIG. 2, the case 5 is formed in a square shape when viewed from the stacking direction of the positive electrode plate 6, the negative electrode plate 7 and the separator 8, and welds the sheets 4 facing each other at the four peripheral edges. This is a four-side sealed bag.

  As a method for welding the sheet 4 of the case 5, for example, thermocompression bonding, ultrasonic welding, or the like can be employed.

  The sheet 4 constituting the case 5 may be any sheet having sufficient strength, barrier properties, and weldability, and a laminate film having a multilayer structure can be used.

  The laminated film constituting the sheet 4 of the case 5 is disposed on the outer surface side (the side opposite to the power storage element 11), and is made of a resin base layer that ensures strength, and the inner surface side (the side facing the power storage element 11). It is preferable to use a resin sealant layer that is disposed on the substrate and has a metal barrier layer that is disposed between the base material layer and the sealant layer and that secures the barrier.

  Examples of the main component of the resin forming the base material layer include polyethylene terephthalate (PET), polypropylene (PP), and polyvinyl chloride (PVC).

  As the main component of the resin forming the sealant layer, it is preferable to use a resin that has not only the weldability of the sheets 4 but also the current collectors 9 and 10. Examples of the main component of the resin that forms the sealant layer include thermoplastic resins such as polyethylene and polypropylene. The average thickness of the sealant layer can be, for example, 50 μm or more and 500 μm or less. An adhesive resin different from the sheet 4 may be disposed between the sheet 4 and the current collectors 9 and 10.

  Examples of the metal forming the barrier layer include aluminum and stainless steel, and aluminum is preferably used. The barrier layer may be formed from a metal foil or may be formed by vapor-depositing a metal on the base material layer.

  The sheet 4 joint portion of the case 5 is preferably formed so that the sheet 4 is parallel to the positive electrode plate 6 and the negative electrode plate 7 of the electricity storage element 11.

<Power storage element>
As described above, the electricity storage element 11 has a laminated electrode body formed by laminating the positive electrode plate 6 and the negative electrode plate 7 with the separator 8 interposed therebetween, and a current collector from the positive electrode plate 6 and the negative electrode plate 7 of the laminated electrode body. 9 and 10 respectively extend.

  The electrode body of the electricity storage element 11 may be a laminate of a single positive electrode plate 6, a negative electrode plate 7 and a separator 8, and the plurality of positive electrode plates 6 and the plurality of negative electrode plates 7 are alternately arranged via the separators 8. It may be laminated. In addition, the electrode body of the power storage element 11 may be obtained by winding a long strip-like positive electrode plate 6 and a negative electrode plate 7 flatly with a separator 8 interposed therebetween, and the long strip-like positive electrode plate 6 and negative electrode plate 7. What laminated | stacked through the separator 8 may be folded into a zigzag (zigzag type). In the case of the zigzag type, it is sufficient that at least one of the positive electrode 6, the negative electrode 7, and the separator 8 is in the form of a long band.

  This electrode body is typically formed in a square shape when viewed from the stacking direction of the positive electrode plate 6, the negative electrode plate 7 and the separator 8 as in this embodiment.

(Positive electrode plate)
The positive electrode plate 6 may have a conductive foil-like or sheet-like positive electrode current collector and a porous positive electrode mixture layer laminated on both surfaces of the positive electrode current collector. .

  As a material of the positive electrode current collector base, a metal such as aluminum, copper, iron, nickel, or an alloy thereof is used. Among these, aluminum, an aluminum alloy, copper, and a copper alloy are preferable from the balance between high conductivity and cost, and aluminum and an aluminum alloy are more preferable. Moreover, as a shape of a positive electrode current collection base material, foil, a mesh, a vapor deposition film, etc. are mentioned, A foil is preferable from the surface of cost. That is, an aluminum foil is preferable as the positive electrode current collecting base material.

  Moreover, as an average thickness of a positive electrode current collection base material, it is 5 micrometers or more and 50 micrometers or less, for example.

  The positive electrode mixture layer is a porous layer formed from a so-called mixture containing a positive electrode active material. Moreover, the composite material which forms a positive electrode composite material layer may contain arbitrary components, such as a electrically conductive agent, a binder (binder), a thickener, and a filler, as needed.

Examples of the positive electrode active material include composite oxides represented by Li _x MO _y (M represents at least one transition metal) (Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _{x MnO 3, Li x Ni α Co} (1-α) O 2, Li x Ni α Mn β Co (1-α-β) O 2, Li x Ni α Mn (2-α) O 4 , etc.), Li _w A polyanion compound (LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ ) represented by Me _x (XO _y ) _z (Me represents at least one transition metal, and X represents, for example, P, Si, B, V, etc.) Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.).

  The conductive agent is not particularly limited. Examples of such a conductive agent include carbon black such as natural or artificial graphite, furnace black, acetylene black, and ketjen black, metals, and conductive ceramics. Examples of the shape of the conductive agent include powder and fiber.

  Examples of the binder include thermoplastic resins such as fluororesin (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), polyethylene, polypropylene, polyimide; ethylene-propylene-diene rubber (EPDM), sulfonated EPDM. , Elastomers such as styrene butadiene rubber (SBR) and fluororubber; polysaccharide polymers and the like.

  Examples of the thickener include polysaccharide polymers such as carboxymethylcellulose (CMC) and methylcellulose. When the thickener has a functional group that reacts with lithium, it is preferable to deactivate this functional group in advance by methylation or the like.

(Negative electrode plate)
The negative electrode plate 7 may have a conductive foil-shaped or sheet-shaped negative electrode current collector and a porous negative electrode mixture layer laminated on both surfaces of the negative electrode current collector. .

  The negative electrode current collecting base material can have the same shape as the positive electrode current collecting base material described above, but the material is preferably copper or a copper alloy. That is, the negative electrode current collector base material of the negative electrode plate 7 is preferably a copper foil. Examples of the copper foil include a rolled copper foil and an electrolytic copper foil.

  The negative electrode composite material layer is a porous layer formed from a so-called composite material containing a negative electrode active material. The composite material forming the negative electrode composite material layer may contain optional components such as a conductive agent, a binder (binder), a thickener, and a filler as necessary.

  As the negative electrode active material, a material capable of inserting and extracting lithium ions is preferably used. Specific examples of the negative electrode active material include metals such as lithium and lithium alloys; metal oxides; polyphosphate compounds; carbon materials such as graphite and amorphous carbon (easily graphitizable carbon or non-graphitizable carbon). Can be mentioned.

(Separator)
The separator 8 is formed from a porous sheet-like or film-like resin, and is infiltrated with an electrolytic solution. The separator 8 separates the positive electrode plate 6 and the negative electrode plate 7 and holds the electrolytic solution between the positive electrode plate 6 and the negative electrode plate 7.

  Examples of the main component of the separator 8 include polyolefins such as polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and chlorinated polyethylene. Derivatives, polyolefins such as ethylene-propylene copolymers, and polyesters such as polyethylene terephthalate and copolymerized polyesters can be employed. Among these, as the main component of the separator 8, polyethylene and polypropylene excellent in electrolytic solution resistance, durability, and weldability are preferably used.

(Current collector)
The current collectors 9 and 10 may have any conductivity, and are typically formed by projecting the positive current collecting base of the positive plate 6 and the negative current collecting base of the negative plate 7. . Moreover, the conductor connected to a positive electrode current collection base material or a negative electrode current collection base material inside case 5 may be sufficient.

  In the present embodiment, the positive electrode current collector 9 and the negative electrode current collector 10 extend in opposite directions from the joint portion (joint line of the sheet 4) of the sheet 4 on the two opposite sides of the rectangular case 5. Yes. Thereby, since the positive electrode current collector 9 and the negative electrode current collector 10 do not interfere (short-circuit), the width of the current collectors 9 and 10 can be made relatively large. Heat of the electrode body in the case 5 can be released relatively efficiently to the connection members 12 and 13 and thus to the cooling member 3.

<Connecting member>
The connecting members 12 and 13 have a pair of contact surfaces 15 arranged at a larger interval than the maximum thickness of the case 5 on both sides in the thickness direction of the joint portion of the sheet 4 of the case 5. The pair of contact surfaces 15 have complementary surface shapes. That is, the connecting members 12 and 13 have a constant thickness in the thickness direction of the sheet 4 in the contact surface 15 when viewed from the thickness direction of the sheet 4. In the present embodiment, the contact surface 15 is a plane perpendicular to the thickness direction of the sheet 4 of the case 5.

  In the electricity storage device 1 of the present embodiment, the pair of connecting members 12 and 13 are arranged on both sides of the case 5 with portions having contact surfaces 15 when viewed from the thickness direction of the sheet 4. Thereby, since the whole electrical storage element 1 can be fixed by hold | maintaining the connection members 12 and 13, the assembly of the said electrical storage apparatus becomes easy. Moreover, in the said electrical storage apparatus, since a pair of connection members 12 and 13 form a clearance gap between the case 5 of the electrical storage element which adjoins, the air cooling of the electrical storage element 1 can be accelerated | stimulated.

  Further, the contact surface 15 preferably overlaps with the joint portion of the sheet 4 when viewed from the thickness direction of the sheet 4. Thereby, the dead space in the power storage device can be reduced, and the energy density of the entire device can be improved.

  The lower limit of the length of the contact surface 15 in the direction along the side edge of the overlapping sheet 4 as viewed from the thickness direction of the sheet 4 is 1/2 of the length of the side edge of the overlapping sheet 4. 2/3 is preferable. On the other hand, the upper limit of the length of the contact surface 15 is preferably 1.2 times the length of the side edges of the overlapping sheets 4 and more preferably 1.1 times. By setting the length of the contact surface 15 to be equal to or greater than the lower limit, sufficient heat dissipation can be obtained and the power storage device 1 can be stably fixed. Further, by setting the length of the contact surface 15 to be equal to or less than the upper limit, it is possible to prevent the dead space from increasing unnecessarily, and to increase the energy density of the power storage device.

  In addition, the connection members 12 and 13 have slits 16 that sandwich the current collectors 9 and 10. That is, the connection members 12 and 13 are pressed against the current collectors 9 and 10 by crushing the slits 16 in a state where the current collectors 9 and 10 are inserted into the slits 16. Thereby, the connection members 12 and 13 can be electrically and mechanically connected to the current collectors 9 and 10 relatively easily.

  Furthermore, one connection member 12, 13 of each power storage element 1 has a cooling surface 17 that contacts the cooling member 3 on the side opposite to the case 5. The power storage element 1 radiates heat from the cooling surface 17 to the cooling member 3.

  As the material of the connection members 12 and 13, a metal having excellent conductivity and thermal conductivity is preferably used. As such a metal, for example, copper, iron, aluminum and the like can be raised, and aluminum is preferably used among them. Moreover, the connection members 12 and 13 may be plated with chromium or the like on the metal surface.

[Holding body]
The holding body 2 holds the plurality of power storage elements 1 side by side in the thickness direction at the joint portion of the sheet 4. Further, the holding body 2 presses the contact surfaces 15 of the connection members 12 and 13 of the energy storage device 1 together. Insulating members 14 are sandwiched between the connecting members 12 and 13 arranged in the thickness direction of the sheet 4. That is, the holding body 2 has a first pressure contact mechanism that electrically connects the connection members 12 and 13 by pressing the contact surfaces 15 of the connection members 12 and 13 together.

  The structure of the holding body 2 can be the same as the structure of the conventional holding body (rack, frame, box, etc.) of the power storage device, except that it has a pressure contact mechanism.

  The first pressure contact mechanism of the holding body 2 can be of any configuration such as a screw or a spring, for example, but the holding body 2 of the present embodiment has a spring 18 that presses the connecting members 12 and 13 as the pressure contact mechanism. By using the spring 18 in this way, the connection members 12 and 13 can be brought into contact with each other relatively easily and reliably and with an appropriate pressure, and electrical connection between the power storage elements 1 can be ensured.

  The pressing force by the first pressing mechanism can be, for example, 0.3 kN or more and 1.0 kN or less, depending on the size of the power storage element 1 and the contact surface 15.

  In addition, the holding body 2 has a second press-contact mechanism that presses the cooling member 3 against the cooling surface 17 of the connection members 12 and 13 on one side of the plurality of power storage elements 1. As this 2nd press-contact mechanism, it can be set as arbitrary structures, such as a screw and a spring, like the 1st press-contact mechanism. Thereby, the thermal connection with each connection member 12 and 13 and the cooling member 3 can be ensured. For example, an elastically compressible sheet having thermal conductivity may be sandwiched between the cooling surface 17 of the connecting members 12 and 13 and the cooling member 3 in order to promote heat transfer.

(Cooling member)
The cooling member 3 may be any member that can take heat away from the connection members 12, 13. For example, a member through which a refrigerant is inserted, a member having a heat radiation fin, a heat pump, or the like can be used. A member through which the refrigerant is inserted is preferably used in that the amount of heat radiation can be increased.

[Insulating material]
The insulating member 14 is sandwiched between adjacent connecting members 12 and 13 that should not be connected when the plurality of power storage elements 1 are connected in series. This prevents the formation of a short-circuit loop in which current circulates between adjacent power storage elements 1.

  The insulating member 14 may be bonded in advance to the contact surface 15 of the power storage element 1. That is, by integrating the insulating member 14 with the power storage element 1, the assembly of the power storage device and the replacement of the power storage element 1 are further facilitated.

  The insulating member 14 may be made of any material as long as it has insulating properties. For example, polypropylene or the like can be used.

  The thickness of the insulating member 14 is preferably as small as possible within a range in which insulation can be ensured. A specific average thickness of the insulating member 14 may be, for example, 50 μm or more and 500 μm or less, and a typical example may be 100 μm.

〔advantage〕
As described above, the power storage device includes the plurality of power storage elements 1 including the connection members 12 and 13 having the pair of contact surfaces 15 arranged at an interval larger than the maximum thickness of the case 5. The electrical connection between the connecting members 12 and 13 is easy. Moreover, since the said electrical storage apparatus can connect the electrical storage element 1 by crimping between the connection members 12 and 13, an assembly and replacement | exchange of the electrical storage element 1 are comparatively easy.

  Moreover, since the said electrical storage apparatus forms a clearance gap between cases 5 because the space | interval of a pair of contact surface 15 is larger than the maximum thickness of case 5, even when case 5 temperature rises, case 5 becomes this clearance gap. Can expand to protrude. Thereby, since the expansion of the case 5 does not separate the connection members 12 and 13, the pressure contact state of the connection members 12 and 13, that is, the electrical connection between the power storage elements 1 can be maintained.

  Further, in the power storage device, since the connection members 12 and 13 have the cooling surface 17 and the cooling member 3 in contact with the cooling surface 17 is provided, each power storage element 1 can be efficiently cooled.

[Second Embodiment]
In FIG. 3, the electrical storage element 1a which concerns on 2nd embodiment of this invention is shown. The power storage element 1a is formed of a flexible sheet 4, and a case 5a in which the sheets 4 are overlapped and joined at at least a part of the peripheral edge, and a positive electrode plate 6 and a negative electrode plate 7 accommodated in the case 5a. And a stack of separators 8 and a power storage element 11 having a pair of current collectors (positive electrode current collector 9a and negative electrode current collector 10a) extending from the positive electrode plate 6 and the negative electrode plate 7 through the joint portion of the case 5a. And a pair of connecting members (positive electrode connecting member 12a and negative electrode connecting member 13a) connected to current collectors 9a and 10a outside case 5a.

  Regarding the power storage element 1a of FIG. 3, the same components as those of the power storage element 1 of FIG.

<Case>
In the electricity storage device 1a of this embodiment, the case 5a is formed in a square shape when viewed from the stacking direction of the positive electrode plate 6, the negative electrode plate 7, and the separator 8, and is formed by welding sheets 4 facing each other at the four peripheral edges. It is a seal-type bag body, and a positive electrode current collector 9a and a negative electrode current collector 10a extend side by side from one side.

<Connecting member>
The connecting members 12a and 13a have a pair of contact surfaces 15a arranged at intervals larger than the maximum thickness of the case 5a on both sides in the thickness direction at the joint portion of the sheet 4 of the case 5a. In the present embodiment, the pair of contact surfaces 15 of the connection members 12a and 13a have complementary concave and convex shapes that fit together. As described above, since the contact surface 15 has the fitting shape, the power storage element 1a can be positioned relatively easily when the power storage device is assembled and when the power storage element 1a is replaced. It is easy and the cooling surface 17 of the some electrical storage element 1a can be made to contact | abut to the cooling member 3 equally.

  In the electricity storage device 1a of the present embodiment, when the pair of connection members 12a and 13a are viewed from the thickness direction of the sheet 4, a portion having the contact surface 15 is disposed on one side of the case 5a. Thereby, all the electrical storage elements 1a can be electrically connected only on one side of the electrical storage device. For this reason, the said electrical storage element 1a can be used suitably for the electrical storage apparatus which can be accessed only from one side in the state integrated in the apparatus.

  The storage element 1a may be provided with a discharge device (not shown) that equalizes the positive electrode potential and the negative electrode potential to make the storage element safe when an abnormality such as an internal short circuit occurs in the storage element 1a. it can. Specifically, the positive electrode connecting member 12a and the negative electrode connecting member 13a are connected via a discharge device, and the positive electrode connecting member 12a and the negative electrode connecting member 13a are energized at the time of abnormality. In the electricity storage device 1a of the present embodiment, since the positive electrode connecting member 12a and the negative electrode connecting member 13a are arranged adjacent to each other, the wiring between the discharge device and the positive electrode connecting member 12a and the negative electrode connecting member 13a can be reduced. Because the wiring is small, the resistance caused by the discharge device can be made relatively small, so that discharge with a relatively large current is possible. Further, space can be saved as the power storage element and the power storage device.

  Further, the connection members 12 a and 13 a have a cooling surface 17 a that contacts a cooling member (not shown) on the side opposite to the case 5. The power storage element 1a can radiate heat from the cooling surface 17c to the cooling member.

[Third embodiment]
In FIG. 4, the electrical storage element 1b which concerns on 3rd embodiment of this invention is shown. The power storage element 1b is formed of a flexible sheet 4, and a case 5a in which the sheets 4 are overlapped and joined at least at a part of the peripheral edge, and a positive electrode plate 6 and a negative electrode plate 7 accommodated in the case 5a. And a stack of separators 8 and a power storage element 11 having a pair of current collectors (positive electrode current collector 9a and negative electrode current collector 10a) extending from the positive electrode plate 6 and the negative electrode plate 7 through the joint portion of the case 5a. And a pair of connection members (a positive electrode connection member 12b and a negative electrode connection member 13b) connected to the current collectors 9a and 10a outside the case 5a.

  Regarding the power storage element 1b in FIG. 4, the same components as those in the power storage element 1 in FIG. 2 or the power storage element 1a in FIG.

<Connecting member>
The connection members 12b and 13b are bent and extended from the side where the current collectors 9a and 10a extend along the joining portion of the sheet 4 on the periphery of the case 5a, and on the side of the adjacent side, A pair of contact surfaces 15b are formed on both sides in the thickness direction at the joint portion of the sheet 4 of the case 5a, and are arranged at a larger interval than the maximum thickness of the case 5a. That is, in the electricity storage device 1b of the present embodiment, when the pair of connection members 12b and 13b are viewed from the thickness direction of the sheet 4, portions having the contact surface 15a are disposed on both sides of the case 5a.

  The connecting members 12b and 13b are arranged at the side where the current collectors 9a and 10a extend, while optimizing the connection structure (for example, caulking structure) with the current collectors 9a and 10a. The contact between the contact surfaces 15a can be optimized in a portion located on the side adjacent to the side on which 10a extends.

  Furthermore, the connection members 12b and 13b have a cooling surface 17b that contacts the cooling member 3 on the side opposite to the case 5 that is located on the side adjacent to the side on which the current collectors 9a and 10a extend. The power storage device 1 can radiate heat from the cooling surface 17b to the cooling member 3.

[Fourth embodiment]
In FIG. 5, the electrical storage element 1c which concerns on 4th embodiment of this invention is shown. The electricity storage element 1c is formed of a flexible sheet 4, and a case 5 in which the sheets 4 are overlapped and joined at least at a part of the peripheral edge, and a positive electrode plate 6, a negative electrode plate 7, and A power storage element 11 having a stack of separators 8 and a pair of current collectors (positive electrode current collector 9 and negative electrode current collector 10) extending from the positive electrode plate 6 and the negative electrode plate 7 through the joint portion of the case 5; A pair of connecting members (a positive electrode connecting member 12c and a negative electrode connecting member 13c) connected to the current collectors 9 and 10 outside the case 5 are provided.

  Regarding the power storage element 1c of FIG. 5, the same components as those of the power storage element 1 of FIG.

<Connecting member>
The positive electrode connecting member 12c and the negative electrode connecting member 13c are formed with a pair of contact surfaces 15c and 15d arranged at intervals larger than the maximum thickness of the case 5a on both sides in the thickness direction at the joint portion of the sheet 4 of the case 5. Yes. The positive electrode connection member 12c and the negative electrode connection member 13c extend along the front surface or the back surface of the case 5, and one contact surface 15c extends to a region overlapping with the positive electrode plate 6 as viewed in the thickness direction.

  In the power storage device using the power storage element 1c, a plurality of contact surfaces 15c of the positive electrode connection member 12c of the power storage element 1c come into contact with one contact surface 15c of the negative electrode connection member 13c of the adjacent power storage element 1c. Power storage elements 1c can be electrically connected in series.

  Further, in the power storage device using the power storage element 1c, between one contact surface 15c of the positive electrode connection member 12c of the power storage element 1c and the other contact surface 15d of the positive electrode connection member 12c of the adjacent power storage element 1c, A short circuit is prevented by sandwiching the insulating member 14c between one contact surface 15c of the negative electrode connection member 13c of the element 1c and the other contact surface 15d of the negative electrode connection member 13c of the adjacent storage element 1c.

  Further, the connection members 12 c and 13 c have a cooling surface 17 c that contacts the cooling member 3 on the side opposite to the case 5. The power storage element 1 can radiate heat from the cooling surface 17c to the cooling member 3. Since the contact surface 15c extends along the surface of the case 5 and is connected to the cooling surface 17c, heat generated not only in the vicinity of the positive electrode current collector 9a and the negative electrode current collector 10a but also in the central portion of the power storage element 1. Can also dissipate heat efficiently.

[Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, the components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.

  The connection of the connection member to the current collector may be performed by, for example, electric welding, ultrasonic welding, or the like.

  The electricity storage device according to the present invention may not have a cooling surface. Therefore, the power storage device according to the present invention may not have a cooling member. Moreover, the cooling surface of the electrical storage element according to the present invention may be a surface other than the surface opposite to the case of the connection member. The cooling member 3 may be a temperature adjustment member, for example. The temperature adjustment member may be heated not only for cooling but also for keeping the temperature of the power storage element constant.

  The power storage device and power storage device according to the present invention can be particularly suitably used as a storage battery for automobiles and the like that require a relatively large capacity.

1, 1a, 1b, 1c Storage element 2 Holding body 3 Cooling member 4 Sheet 5, 5a Case 6 Positive electrode plate 7 Negative electrode plate 8 Separator 9, 9a Positive electrode current collector 10, 10a Negative electrode current collector 11 Storage element 12, 12a, 12b, 12c Positive electrode connecting members 13, 13a, 13b, 13c Negative electrode connecting members 14, 14c Insulating members 15, 15a, 15b, 15c, 15d Contact surface 16 Slits 17, 17a, 17b, 17c Cooling surface 18 Spring

Claims (10)

A case formed of a flexible sheet, the flexible sheet being overlapped and joined at least at a part of the peripheral edge;
A positive electrode plate and a negative electrode plate housed in the case, and a power storage element having a pair of current collectors extending from the positive electrode plate and the negative electrode plate to the outside through the joint portion of the case;
A pair of connecting members connected to the current collector outside the case,
The electrical storage element in which the said connection member has a pair of contact surface arrange | positioned by the space | interval larger than the maximum thickness of the said case on the sheet | seat thickness direction both sides in the junction part of the said sheet | seat.   The electric storage element according to claim 1, wherein the contact surface overlaps with the joint when viewed from the sheet thickness direction.   The power storage element according to claim 2, wherein a length along a side edge of the sheet overlapping the contact surface is ½ or more of a length of the side edge.   The electric storage element according to claim 1, 2 or 3, wherein portions having contact surfaces of the pair of connecting members are disposed on both sides of the case when viewed from the sheet thickness direction.   The power storage element according to any one of claims 1 to 4, wherein the pair of current collectors extend from the case in directions opposite to each other.   The electric storage element according to any one of claims 1 to 5, wherein the contact surface is a plane perpendicular to the sheet thickness direction.   The power storage element according to any one of claims 1 to 5, wherein the pair of contact surfaces have shapes that fit with each other.   The power storage element according to claim 1, wherein the connection member has a slit for sandwiching the current collector. A plurality of power storage elements according to any one of claims 1 to 8,
A holding body that holds the plurality of power storage elements side by side in the sheet thickness direction,
A power storage device in which contact surfaces of connection members of the plurality of power storage elements are pressed against each other by the holding body.   The power storage device according to claim 9, wherein the holding body includes a spring that presses the connection member.

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