JP2013122936A - Nonaqueous electrolyte solution secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte solution secondary battery whose cost is reduced by realizing reduction of the number of components and simplification of a manufacturing process, which prevents deterioration of quality due to evaporation of an electrolyte solvent and leakage of an electrolyte solution by making it possible to pour the electrolyte solution after assembling of a fuel cell, and whose sealing of an electrolyte solution pouring hole is simplified.SOLUTION: A nonaqueous electrolyte solution secondary battery comprises a case and a cover. The case and the cover are made of a metal plate whose at least external faces are coated by an insulating resin film. In the nonaqueous electrolyte solution secondary battery with its case and cover sealed airtight in a tighten winding method, a terminal provided with an electrolyte pouring hole is formed on the cover through an insulating member.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery used for an electric vehicle or the like.

With the rapid reduction in size and weight of electronic devices, there is an increasing demand for the development of secondary batteries that are small, lightweight, have high energy density, and can be repeatedly charged and discharged with respect to the battery that is the power source. In addition, due to environmental problems such as air pollution and an increase in carbon dioxide, early commercialization of electric vehicles is desired, and an excellent secondary battery having features such as high efficiency, high output, high energy density, and light weight. Development is desired.

As secondary batteries that satisfy these requirements, secondary batteries using non-aqueous electrolytes have been put into practical use. This battery has an energy density several times that of a battery using a conventional water-soluble electrolyte. For example, lithium-containing layered cobalt oxide (hereinafter referred to as “Co-based compound”), lithium-containing layered nickel oxide (hereinafter referred to as “Ni-based compound”) or the positive electrode of the non-aqueous electrolyte secondary battery A long-life nonaqueous electrolyte secondary battery using a spinel-type lithium-manganese composite oxide (hereinafter referred to as “Mn-based compound”) and using a carbon material that can store and release lithium in the negative electrode has been put into practical use. ing.

In the development of non-aqueous secondary electrolyte batteries for use in electric vehicles and the like, further cost reduction has become an important development issue as well as improved performance. Compared to lead-acid batteries and nickel-metal hydride batteries, the cost of non-aqueous electrolyte secondary batteries remains high, which is a major obstacle to popularization.

In order to reduce the cost of non-aqueous electrolyte secondary batteries, it is important to improve the materials that make up the electrode group, such as active materials, electrolytes, and separators, but it is also important to improve other battery components and production methods. It is.

Examples of improvements reported to date include Patent Document 1, Patent Document 2, and Patent Document 3.
Discloses a technique for increasing productivity by using a metal plate for a battery case and a lid and sealing hermetically by a winding method. Patent Document 4 discloses a technique in which an exterior case is formed of a film laminated metal material to reduce the number of parts.

Furthermore, in patent document 5, in the square battery airtightly sealed by the double winding method,
A technique for improving hermetic performance by coating at least the inner surfaces of a battery case and a lid with a resin film is disclosed.

On the other hand, there are a number of technologies for providing an electrolyte injection hole in a battery, housing an electrode group in the battery case, welding the battery case and the lid, and then injecting the electrolyte and sealing the electrolyte injection hole. It is disclosed. For example, in Patent Document 6, the liquid injection hole formed in the battery lid is hermetically sealed by ultrasonic welding with an aluminum sealing plug. Further, in Patent Document 7, an electrolyte solution injection hole is provided in a battery terminal, and a screw is screwed into the electrolyte solution injection hole and sealed. In Patent Document 8, an insulating member is provided on a metal plate of the battery header. An electrolyte solution injection hole is provided in a battery terminal formed via a plug, and a sealing material is joined and sealed to the electrolyte solution injection hole by resistance welding.
Japanese Patent No. 3482604 Japanese Patent Laid-Open No. 09-073885 Japanese Patent Laid-Open No. 11-040115 JP 2002-324723 A Japanese Patent No. 3427216 Japanese Patent No. 3614891 JP 11-339769 A JP 2005-158267 A

The techniques disclosed in Patent Document 1, Patent Document 2 and Patent Document 3 are to hermetically seal the battery case and lid by a winding method, but since the case and lid use metal, When handling a battery, there is a high possibility of a short circuit, and in order to avoid this, it is necessary to cover the outside of the battery with an insulating material such as a heat-shrinkable resin, resulting in an increase in the number of parts and manufacturing processes.

In addition, the techniques disclosed in Patent Document 4 and Patent Document 5 are intended to reduce costs by reducing the number of parts by using a laminated metal material and simplifying the production process. However, in these technologies, problems during manufacturing that cause problems when using laminated metal materials for battery outer bodies, specifically, volatilization and scattering of electrolyte in the tightening process after electrolyte injection, In addition, there is a defect that does not take into account the deterioration in quality associated therewith, and there is a problem that the effects of these inventions cannot be enjoyed in an actual manufacturing site.

In Patent Document 4, since the upper sealing plate of the battery is not designated as a film laminate metal body, there is a risk that a short circuit may occur in the sealing plate portion when the sealing plate is metal.

According to our study, when a metal plate laminated with an insulating resin film is used for a battery case or lid, the entire surface of the battery is not covered with an insulator except for the terminal part which is a current-carrying part. As far as it can be seen, it is impossible to achieve low cost while achieving both productivity and quality. This is the same as Patent Document 5.

However, in Patent Document 5, various problems occur due to the opening of the battery case being used as an electrolyte injection hole. Since dimethyl carbonate, diethyl carbonate, and the like, which are typical organic solvents used in the non-aqueous electrolyte, are second petroleums like kerosene, they have a property of volatilizing easily even at room temperature.

Therefore, when an electrolyte is injected into a battery having an opening that is wide enough to be tightened, the solvent volatilization or moisture absorption through the opening is maintained until airtightness is maintained in the subsequent tightening process. As a result, the composition of the electrolytic solution is easily changed, and there is a problem that quality stability cannot be maintained.

The volatile organic gas drifting in the production line is also a safety issue. In addition, since the electrolyte easily leaks during manufacturing, if the electrolyte adheres to the tightening portion, there is a problem in the airtightness of the battery. If the electrolyte adheres to the outer surface of the case, the electrolyte May react with moisture to generate corrosive gas. In particular, in a battery that is hermetically sealed by a tightening method, the battery is likely to vibrate during the tightening process, so that it is necessary to have a structure in which liquid leakage hardly occurs.

Further, when the method for sealing a liquid injection hole disclosed in Patent Document 6 is applied to a battery case or a battery in which a liquid injection hole is provided and a battery whose lid is covered with a resin film, a sealing member and a metal battery are used during resistance welding. Since the contact with the case is hindered by the resin film, there arises a problem that resistance welding cannot be performed or pin holes are generated due to insufficient resistance. Therefore, in the present invention, the structure disclosed in Patent Document 7 and Patent Document 8 in which a liquid injection hole is provided in the battery terminal is adopted.

Accordingly, an object of the present invention is to reduce the number of parts and simplify the manufacturing process, thereby reducing the cost, and by allowing the electrolyte injection work after the battery assembly process to be performed, thereby volatilizing the electrolyte solvent. Another object of the present invention is to provide a non-aqueous electrolyte secondary battery in which deterioration of quality due to leakage of electrolyte or electrolyte is prevented and the electrolyte injection hole is easily sealed.

The invention according to claim 1 includes a case and a lid, wherein the case and the lid are made of a metal plate whose outer surface is coated with an insulating resin film, and the case and the lid are hermetically sealed by a tightening method. The non-aqueous electrolyte secondary battery is characterized in that a terminal having an electrolyte injection hole is formed on the lid via an insulating member.

According to the present invention, since the case and lid are both made of a metal plate having at least the outer surface covered with an insulating resin film, an insulation coating step after the battery is manufactured becomes unnecessary, which reduces the manufacturing cost. Reduction is possible. Moreover, the opening of the case is not used as the electrolyte injection hole, and the injection hole is provided in the terminal portion, so that quality stability can be ensured without impairing the purpose of insulating the exterior body.

In addition, since the sealing process is extremely simple and there are very few defects in the hermetic sealing, the productivity of the battery is further increased and the cost can be further reduced.

Hereinafter, the present invention will be described in detail, but it goes without saying that the present invention is not limited to the following embodiments.

A non-aqueous electrolyte secondary battery according to the present invention includes a case and a lid, and the case and the lid are each made of a metal plate whose outer surface is covered with an insulating resin film, and the case and the lid are tightened together. In the non-aqueous electrolyte secondary battery hermetically sealed by the method, an electrolyte solution injection hole is provided in the lid via an insulating member.

The non-aqueous electrolyte secondary battery having such characteristics is low in cost and excellent in quality stability, and can be used as a power source for devices such as electric vehicles and mobile phones that are premised on mass dissemination.

Examples of the appearance of the non-aqueous electrolyte secondary battery according to the present invention are shown in FIGS.
As shown in FIG. FIG. 1 shows an external appearance when the battery is constituted by a two-piece can, and FIG. 2 shows an external appearance when the battery is constituted by a three-piece can. 3 is a cross-sectional view taken along the line AA ′ of FIG. 1 when the battery is formed of a two-piece can, and FIGS. 4 and 5 are A--sections of FIG. 2 when the battery is formed of a three-piece can. FIG. 4 is a cross-sectional view of A ′, FIG. 4 shows a case where the positive electrode terminal and the negative electrode terminal are provided on the same lid, and FIG. 5 shows a case where the positive electrode terminal and the negative electrode terminal are provided on different lids.

1 to 5, 1 is a battery case, 2 is a lid, 2 'is a positive terminal, 4 is a negative terminal,
5 is a tightening portion, and 6 is an insulating member. In these batteries, the positive electrode terminal 3 and the negative electrode terminal 4 are provided on the lid 2 via an insulating member 6.

When the battery is composed of a two-piece can, as shown in FIG. 1, the battery case is made by drawing or the like in which the side plate and the bottom plate are integrated, and the lid 2 is one. Yes, as shown in FIG. 3, one lid is provided with a positive terminal portion and a negative terminal portion. Further, when the battery is constituted by a three-piece can, as shown in FIG. 2, the battery case refers only to the side plate, and the lid includes two of the upper surface (2) and the lower surface (2 ′). As shown in FIG. 5, the positive electrode terminal and the negative electrode terminal may be provided on the same lid, or may be provided on different lids as shown in FIG.

In FIG. 1, the battery case 1 and the lid 2 are hermetically sealed by tightening. In FIG. 2, the battery case 1 and the upper lid 2 and the battery case 1 and the lower lid 2 'are hermetically sealed by tightening. Yes.

The number of times of tightening is not particularly specified as long as the electrolyte in the battery does not decrease due to leakage or volatilization. In addition, as long as the resin coated on the metal plate plays the role of a sealing material, no sealing material is required, but ethylene is used to ensure long-term durability and reliability at high temperatures. A rubber material having excellent electrolytic solution resistance such as propylene and styrene butadiene may be additionally used.

In addition, when manufacturing the non-aqueous electrolyte secondary battery according to the present invention, in order to further promote cost reduction, a two-piece can having only one tightening portion is preferable, but a three-piece can is used. However, the effect by this invention can be expressed.

In the non-aqueous electrolyte secondary battery according to the present invention, the battery case and the lid are both characterized in that a metal plate whose outer surface is covered with an insulating resin film is used. When the outer surface of the battery case and lid is covered with an insulating resin film, it prevents leakage due to contact between the batteries when a large number of batteries are connected in series or short-circuiting by a working tool, and printing on the insulating resin film And printing.

The material of the insulating resin film is not particularly specified, but in consideration of cost, workability, solvent resistance, etc., epoxy, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polyphenylene sulfide, polyimide, polyamide and the like are preferable.
Among these, polyethylene terephthalate and polypropylene are particularly preferable.

The covering with the insulating resin film is essential on the outer surfaces of the case and the lid, but the inner surface may be covered. In particular, when the inner surface is coated, since the electrolytic solution contains an organic solvent, it is necessary to select a resin having high solvent resistance so that it does not dissolve in the organic solvent and does not react with the organic solvent.

The insulating resin film that covers the outer surface of the battery needs to have a certain strength to withstand physical impact from the outside, and it is necessary to select a material that is easy to print. For example, polyethylene terephthalate (PET) is optimal. Moreover, as an insulating resin film which coat | covers a battery inner surface, it is necessary not to melt | dissolve in electrolyte solution solvent, and not to react with electrolyte solution, for example, polypropylene (PP) is the optimal.

The material of the metal plate is not particularly specified as long as the gist of the present invention is not impaired, but the cost, workability,
In consideration of corrosion resistance and the like, nickel-plated iron, stainless steel, aluminum alloy and the like are preferable as in the case of conventional battery case materials on the market. In particular, when the inner surface is not coated with a resin, the metal plate needs to be made of a material that is highly resistant to corrosion and electrolyte.

The method for coating the metal plate with the resin film includes thermocompression bonding of the film, adhesion using an adhesive, application and drying of a solution or dispersion, etc., but is not particularly specified unless pinholes are generated or peeled off. In addition, the thickness of the resin layer after coating is insulated so that it has a sufficient withstand voltage even when the batteries according to the present invention are combined in series, and when an assembly tool such as a spanner or a driver is accidentally bumped. It is necessary to have a sufficient thickness so as not to break. However, since excessive thickness impairs the workability at the time of winding, about 10-100 micrometers is preferable.

FIG. 6 shows a cross-sectional structure of the terminal portion of the nonaqueous electrolyte secondary battery according to the present invention. In FIG.
3 and 6 show the same thing as FIG. 1, 7 is an electrolyte solution injection hole, 8 is a collector. As shown in FIG. 6, a positive electrode terminal 3 is formed on the lid 2 via an insulating member 6, and an electrolyte solution injection hole 7 is provided in the positive electrode terminal 3. The positive electrode terminal 3 is connected to the current collector 8 inside the battery, and FIG.
Although not shown, the current collector 8 is connected to the positive electrode of the electrode group. In addition, although FIG. 6 demonstrated the positive electrode terminal as an example, the structure at the time of providing an electrolyte solution injection hole in a negative electrode terminal is also the same as FIG.

When a liquid injection hole is provided in the battery case or lid, the battery case or lid is covered with an insulating resin film, so that the electrical contact between the sealing material and the metal case or lid is insufficient, and sealing is performed. However, if the metal terminal has an electrolyte injection hole as in the present application, hermetic sealing is simple and reliable. No insulation after sealing is necessary.

The injection hole must have a sufficiently large hole diameter for smooth injection of the electrolyte, but if it is too large, vacuum injection will be difficult, and volatilization and leakage of the electrolyte will be difficult. In addition, since the subsequent sealing becomes difficult, an appropriate range of pore diameters is desired. When reference is made to examples of performance in conventional small batteries and large batteries, the hole diameter is preferably about 0.2 mm to 3.9 mm.

Moreover, although there is no designation | designated of the sealing method, when the past performance is also considered here, the welding sealing by resistance heating, the welding sealing by a laser, etc. are preferable. As long as the sealant or the like can be used together to maintain sufficient airtightness, screwing may be used.

The BB 'cross section of FIG. 1 of the nonaqueous electrolyte secondary battery of this invention is shown in FIGS. 7 to 9
1 to 8 are the same as those in FIGS. 1 and 6, and 9 is an electrode group. As shown in FIG. 7 to FIG. 9, the non-aqueous electrolyte secondary battery includes a battery container in which an electrode group in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween, and the electrode group is impregnated with the non-aqueous electrolyte. Configured. The structure of the electrode group is as follows: a winding type in which strip electrodes are wound as shown in FIG. 7, a stacked type in which flat electrodes are stacked as shown in FIG. 8, and a strip electrode is shifted as shown in FIG. Various types of structures such as a folded type can be used.

In the non-aqueous electrolyte secondary battery of the present invention, as shown in the cross-sectional structure in FIG. 10, it is preferable that the height of the terminal is higher than the height of the tightening portion. That is, when the battery is placed so that the terminal is in the upward direction as shown in FIG. By adopting such a structure, when a large number of batteries are connected to form an assembled battery, it is very easy to connect adjacent unit cells, and the effect of reducing the production cost is increased.

As the positive electrode, the negative electrode, the separator, the electrolytic solution, and the like used for the non-aqueous electrolyte secondary battery, there are no particular differences from those conventionally used, and commonly used ones can be used.

That is, the positive electrode material used for the nonaqueous electrolyte secondary battery of the present invention is not particularly limited,
Various materials can be used as appropriate. For example, transition metal compounds such as manganese dioxide, spinel type lithium manganate, vanadium pentoxide, transition metal chalcogen compounds such as iron sulfide and titanium sulfide, and composite oxides of these transition metals and lithium Li _x MO _2- δ (
M represents Co, Ni, or Mn, and is a composite oxide in which 0.4 ≦ x ≦ 1.2 and 0 ≦ δ ≦ 0.5), or Al, Mn, Fe, Ni, Co, Cr, T
A compound containing at least one element selected from i, Zn, and Zr, or a non-metallic element such as P or B can be used.

Further, preferably a complex oxide of lithium and nickel, that is, Li _x Ni _p M1 _q M
Positive electrode active material represented by 2 _r O ₂₋ δ (where M1 and M2 are Al, Mn, Fe, Co, C
It may be at least one element selected from r, Ti, Zn, and Zr, or a nonmetallic element such as P or B. Furthermore, 0.4 ≦ x ≦ 1.2, 0.8 ≦ p + q + r ≦ 1.2, 0 ≦ δ ≦ 0.
5). Examples of the organic compound include conductive polymers such as polyaniline. Furthermore, the above various active materials may be mixed and used regardless of whether they are inorganic compounds or organic compounds.

Examples of the negative electrode material include Al, Si, Pb, Sn, Zn, Cd, and lithium alloys, metal oxides such as LiFe ₂ O ₃ , WO ₂ , MoO ₂ , SiO, CuO, and non-graphitizable carbon. Or amorphous carbonaceous materials such as graphitizable carbon, crystalline carbon materials such as graphite, lithium nitride such as Li ₃ N, lithium titanate, metallic lithium, or a mixture thereof may be used. The body may be used. It is particularly preferable to use an amorphous carbon material.

Nonaqueous solvents used for the nonaqueous electrolyte include ethylene carbonate, propylene carbonate,
Butylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, γ
-Valerolactone, sulfolane, 1,2-dimethoxyethane, 1,2-diethoxyethane,
Tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyl-1,3-dioxolane and dioxolane, fluoroethyl methyl ether, ethylene glycol diacetate,
Propylene glycol diacetate, ethylene glycol dipropionate, propylene glycol dipropionate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate , Methylpropyl carbonate, ethylpropyl carbonate, dipropyl carbonate, methyl isopropyl carbonate, ethyl isopropyl carbonate, diisopropyl carbonate, dibutyl carbonate, acetonitrile, fluoroacetonitrile, ethoxypentafluorocyclotriphosphazene, diethoxytetrafluorocyclotriphosphazene, phenoxypentafluoro Cyclotriphosphazene Alkoxy and halogen substituted cyclic phosphazenes and of a chain phosphazenes, triethyl phosphate, phosphoric acid esters such as trimethyl phosphate, trioctyl phosphate, triethyl borate, boric acid esters such as tributyl borate,
Nonaqueous solvents such as N-methyloxazolidinone and N-ethyloxazolidinone can be used alone or a mixed solvent thereof.

The nonaqueous electrolytic solution is used by dissolving a lithium electrolyte in the above nonaqueous solvent. As the electrolyte, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ CO ₂ , LiCF
₃ SO ₃ , LiCF ₃ CF ₂ SO ₃ , LiCF ₃ CF ₂ CF ₂ SO ₃ , LiN (SO ₂ C
F ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , LiN (COCF ₃ ) ₂ , LiN (COC
It is possible to use salts such as F ₂ CF ₃ ) ₂ , LiBF ₂ C ₂ O ₄ , LiBC ₄ O ₈ , LiPF ₂ (C ₂ O ₄ ) ₂ and LiPF ₃ (CF ₂ CF ₃ ) ₃ or mixtures thereof. it can.

In order to improve battery characteristics, a small amount of a compound may be mixed in the non-aqueous electrolyte. Vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate, phenyl vinylene carbonate, vinyl ethylene carbonate,
Carbonates such as divinylethylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, fluoroethylene carbonate, vinyl esters such as vinyl acetate and vinyl propionate, diallyl sulfide, allyl phenyl sulfide,
Sulfides such as allyl vinyl sulfide, allyl ethyl sulfide, propyl sulfide, diallyl disulfide, allyl ethyl disulfide, allyl propyl disulfide, allyl phenyl disulfide, 1,3-propane sultone, 1,4-butane sultone,
Cyclic sulfonates such as 1,3-propensultone and 1,4-butene sultone,
Methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, propyl ethanesulfonate, methyl benzenesulfonate, ethyl benzenesulfonate, propyl benzenesulfonate, phenyl methanesulfonate, Chain sulfonate esters such as phenyl ethane sulfonate, phenyl propane sulfonate, methyl benzyl sulfonate, ethyl benzyl sulfonate, propyl benzyl sulfonate, benzyl methane sulfonate, benzyl ethane sulfonate, and benzyl propane sulfonate, dimethyl mons Phyto, diethyl sulfite, ethyl methyl sulfite, methyl propyl sulfite, ethyl propyl sulfite, diphenyl sulfite, methyl phenyl sulfite Sulphites such as zinc, ethylene sulfite, vinyl ethylene sulfite, divinyl ethylene sulfite, propylene sulfite, vinyl propylene sulfite, butylene sulfite, vinyl butylene sulfite, vinylene sulfite, phenylethylene sulfite, dimethyl sulfate , Diethyl sulfate,
Sulfates such as ethylene glycol sulfate, propylene glycol sulfate, butylene glycol sulfate, pentene glycol sulfate, benzene,
Toluene, xylene, fluorobenzene, biphenyl, cyclohexylbenzene, 2-fluorobiphenyl, 4-fluorobiphenyl, diphenyl ether, tert-butylbenzene, orthoterphenyl, metaterphenyl, naphthalene, fluoronaphthalene, cumene, fluorobenzene, 2,4 -Add aromatic compounds such as difluoroanisole, halogen-substituted alkanes such as perfluorooctane, silyl esters such as tristrimethylsilyl borate, bistrimethylsilyl sulfate, tristrimethylsilyl phosphate, tetrakistrimethylsilyl titanate, etc. May be.

As the separator, woven fabric, non-woven fabric, synthetic resin microporous membrane, etc. can be used.
A synthetic resin microporous membrane can be suitably used. Among them, a microporous membrane made of polyethylene and polypropylene, a microporous membrane made of polyethylene and polypropylene combined with aramid or polyimide, or a polyolefin-based microporous membrane such as a microporous membrane composited with these,
It is preferably used in terms of film strength, film resistance and the like.

As other battery components, there are a winding core, a current collector, an insulating plate, and the like. However, these components may be used as they are.

The shape of the battery is not particularly limited, and can be applied to non-aqueous electrolyte secondary batteries having various shapes such as a rectangular shape, a long cylindrical shape, and a cylindrical shape that can be wound and sealed.

  Examples of the present invention will be described below together with comparative examples.

[Examples 1 to 11 and Comparative Examples 1 to 4]
[Example 1]
Polypropylene (P) on both sides of an aluminum alloy (JIS3003) plate with a thickness of 0.8 mm
P) A metal plate coated with an insulating layer of about 100 μm was prepared by thermocompression bonding of the film. Next, this metal plate is punched and drawn to obtain a width of 100 mm, a thickness of 20 mm, and a depth of 80 mm.
A battery case with a bottom was prepared.

A winding flange was provided at the opening of the battery case. Moreover, said metal plate was cut out according to the dimension of the battery case opening part, and the cover provided with the opening part for attaching a positive electrode terminal and a negative electrode terminal was produced.

A stainless steel positive electrode terminal and a negative electrode terminal were respectively attached to the lid via an airtight resin packing. A through hole having a diameter of 1 mm was provided in the positive electrode terminal, and this was used as an electrolyte injection hole.

Next, the positive electrode was mixed with 87% by weight of LiCoO ₂ powder, 5% by weight of acetylene black as a conductive additive, and 8% by weight of polyvinylidene fluoride as a binder, and the water content was 50p.
N-methyl-2-pyrrolidone (NMP) of pm or less was added to form a paste slurry on an aluminum foil and dried.

For the negative electrode, 90% by weight of artificial graphite powder and 10% by weight of polyvinylidene fluoride as a binder were mixed, and NMP was added to this to form a paste slurry on the copper foil.
Made by drying.

The positive electrode and the negative electrode were dried at 150 ° C. for 12 hours or more under a vacuum of 0.01 torr or less, and then cooled to room temperature and then roll-pressed. Next, the positive electrode and the negative electrode were wound through a polyethylene separator to form an electrode group.

The positive electrode in this electrode group and the positive electrode terminal attached to the lid are joined via a positive electrode current collector,
The lid, the positive and negative electrode terminals, and the electrode group were integrated by joining the negative electrode in the electrode group and the negative electrode terminal attached to the lid via a negative electrode current collector. Next, the electrode group was housed in the case, the lid and the case flange were overlapped, and then the lid and the case were integrated by double winding. The appearance of the obtained battery is the same as that of the two-piece can shown in FIG.

The electrolyte solution was injected through a through hole (electrolyte solution injection hole) provided in the positive electrode terminal. In the electrolytic solution, LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate (EC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 3: 2: 5 (volume ratio) so as to be 1 mol / L. A thing was used.

After pouring, the through hole provided in the positive terminal was plugged with a small piece of aluminum alloy and sealed by laser welding to complete the battery.

[Example 2]
A battery of Example 2 was fabricated in the same manner as Example 1 except that the case and lid were configured as the same three-piece can as shown in FIG.

[Example 3]
A battery of Example 3 was produced in the same manner as Example 1 except that polyethylene terephthalate (PET) was thermocompression bonded to both surfaces of an aluminum alloy (JIS3003) plate instead of polypropylene (PP).

[Example 4]
A battery of Example 4 was produced in the same manner as in Example 1 except that maleic anhydride-modified polypropylene was sandwiched between the aluminum alloy plate and the polypropylene (PP) film and thermocompression bonded.

[Example 5]
A battery of Example 5 was made in the same manner as Example 1 except that a nickel-plated iron plate was used instead of the aluminum alloy plate.

[Example 6]
A battery of Example 6 was made in the same manner as Example 1 except that the coating thickness of the polypropylene (PP) film was 10 μm.

[Example 7]
A battery of Example 7 was made in the same manner as Example 1 except that an ethylene butadiene rubber plate having a thickness of 50 μm was inserted into the joint for winding when the case and the lid were wound.

[Example 8]
A battery of Example 8 was made in the same manner as in Example 1 except that only one side of the aluminum alloy plate was coated with a polypropylene (PP) film and the coated surface was used as the battery outer surface.

[Example 9]
Example 1 except that one side of the aluminum alloy plate was coated with a polypropylene (PP) film, the other side was coated with polyethylene terephthalate (PET), and the surface coated with PET was used as the battery outer surface. 9 batteries were produced.

[Example 10]
The configuration of the case and lid is the same three-piece can as shown in FIG. 2, the cross-sectional structure is the same as that shown in FIG. 5, the positive electrode terminal is provided on the upper lid, the negative electrode terminal is provided on the lower lid, and the terminal A battery of Example 10 was made in the same manner as Example 1 except that the lid provided with was different.

[Example 11]
The configuration of the case and lid is the same two-piece can as shown in FIG. 1, and the cross-sectional structure is the same as shown in FIG. 10, except that the upper surface of the terminal protrudes from the upper surface of the winding portion. A battery of Example 11 was made in the same manner as Example 1.

[Comparative Example 1]
A battery of Comparative Example 1 was fabricated in the same manner as in Example 1 except that the aluminum alloy plate was not covered with the insulating resin film and the case was covered with a heat-shrinkable resin tube after the battery was completed.

[Comparative Example 2]
A battery of Comparative Example 2 was produced in the same manner as in Example 1 except that the battery case was covered with PP but the lid was not covered with an insulating resin film. Produced.

[Comparative Example 3]
Implemented except that the positive electrode terminal was not provided with a through-hole serving as an electrolyte injection hole, and the case filled with the electrolyte was impregnated with an integrated body consisting of a lid, a terminal part, and an electrode group, and then sealed by winding. A battery of Comparative Example 3 was produced in the same manner as Example 1.

[Comparative Example 4]
The positive electrode terminal is not provided with a through-hole serving as an electrolyte injection hole, and only the electrode group portion of the integrated body consisting of the lid, terminal portion, and electrode group is impregnated with the electrolyte, and then stored in the case, and then tightened. A battery of Comparative Example 4 was produced in the same manner as Example 1 except that it was sealed by processing.

  The contents of the batteries prepared in Examples 1 to 11 and Comparative Examples 1 to 4 are summarized in Table 1.

[Characteristic measurement]
The batteries of Examples 1 to 11 and Comparative Examples 1 to 4 were compared in terms of unit cell productivity and occurrence of airtight defects, assembled battery productivity and occurrence of defects, and assembled battery life performance.

[Comparison of productivity of single cells]
A comparison of productivity when 100 cells of each unit cell were manufactured was performed. Here, “cell productivity” is shown as a relative value of the time required to produce 100 cells each, and the smaller the value, the shorter the required time and the higher the productivity. Here, the time required for the production of the battery of Example 1 was set to 100.

[Is there any airtight defect in the cell?]
100 cells of each unit cell were manufactured, and the presence or absence of airtight failure was examined from the presence or absence of weight loss when the batteries were held for 1 minute under a reduced pressure of 1 kPs.

[Battery productivity and presence / absence of defects during battery manufacturing]
The productivity when 5 sets of 8 series assembled batteries were produced using each of the above batteries was compared. Here, “productivity of assembled battery” is indicated by a relative value of the time required for producing 10 sets, and the smaller the value, the shorter the required time and the higher the productivity. Here, the time when the assembled battery was manufactured using the battery of Example 1 was set to 100. In addition, the presence or absence of defects during the production of the assembled battery was also examined. Here, “defect occurrence” means liquid leakage from the single cells, short circuit between the single cells, and the like.

[Battery life performance]
In an environment of 25 ° C., the battery is charged to 4.1 V with a constant current of 1 hour, and further charged with a constant voltage of 4.1 V until the total charging time becomes 3 hours, and then charged with a current of 1 hour. Charging / discharging to 0V was repeated 3 times, and the third discharge capacity was determined as the initial discharge capacity. The average value of the five sets of discharge capacities was defined as the initial average discharge capacity.

Next, the discharge capacity after being charged / discharged 100 times under the same charge / discharge conditions as the initial discharge capacity measurement,
The average value of the five sets of discharge capacities was defined as the average discharge capacity after charging and discharging, and the value obtained by dividing this by the initial average discharge capacity was defined as the capacity retention rate.

Table 2 summarizes the results of unit cell productivity, unit cell hermeticity failure occurrence, battery assembly productivity, unit battery failure occurrence, and unit battery capacity retention rate.

From the results shown in Tables 1 and 2, the case and the lid are made of a metal plate covered with an insulating resin film, the terminal is provided with an electrolyte injection hole, and the case and the lid are tightened. It has been clarified that the non-aqueous electrolyte secondary battery characterized by being hermetically sealed is excellent in productivity, has few airtight defects, and has an effect on cost reduction.

In addition, when the unit cell has a structure in which the upper surface of the terminal protrudes from the upper surface of the tightening portion, it is easy to connect the cells, and thus the productivity when forming the assembled battery is particularly excellent. I understood it.

The figure which shows the external appearance in case the battery is comprised by 2 piece cans. The figure which shows the external appearance in case a battery is comprised by 3 piece cans. The figure which shows the cross section in case the battery is comprised by 2 piece cans. The figure which shows a cross section when a battery is comprised by 3 piece cans and the positive electrode terminal and the negative electrode terminal were provided in the same lid | cover. The figure which shows a cross section when a battery is comprised by 3 piece cans and the positive electrode terminal and the negative electrode terminal were provided in the different lid | cover. The figure which shows the cross-section of the terminal part of the nonaqueous electrolyte secondary battery which concerns on this invention. The figure which shows the cross section of the nonaqueous electrolyte secondary battery using the winding type electrode group which wound the strip | belt-shaped electrode. The figure which shows the cross section of the nonaqueous electrolyte secondary battery using the laminated electrode group which laminated | stacked the flat electrode. The figure which shows the cross section of the non-aqueous-electrolyte secondary battery using the bending type electrode group which folds the strip | belt-shaped electrode. The figure which shows the cross section of the nonaqueous electrolyte secondary battery of the structure where the upper surface of a terminal protrudes from the upper surface of a winding part.

DESCRIPTION OF SYMBOLS 1 Battery case 2, 2 'cover 3 Positive electrode terminal 4 Negative electrode terminal 5 Tightening part 6 Insulation member 7 Electrolyte injection hole 8 Current collector 9 Electrode group

The invention according to claim 1 includes a case and a lid, wherein the case and the lid are made of a metal plate whose outer surface is coated with an insulating resin film, and the case and the lid are hermetically sealed by a tightening method. In the non-aqueous electrolyte secondary battery, a track-shaped terminal provided with an electrolyte injection hole is formed in the lid via an insulating member, and the upper surface of the terminal is formed from the upper surface of the tightening portion between the case and the lid. Is characterized by protruding .

According to the present invention, since the case and lid are both made of a metal plate having at least the outer surface covered with an insulating resin film, an insulation coating step after the battery is manufactured becomes unnecessary, which reduces the manufacturing cost. Reduction is possible. Moreover, the opening of the case is not used as the electrolyte injection hole, and the injection hole is provided in the terminal portion, so that quality stability can be ensured without impairing the purpose of insulating the exterior body. Furthermore, since the upper surface of the terminal protrudes from the upper surface of the tightening portion of the case and the lid, when connecting a large number of batteries to make an assembled battery, it is very easy to connect adjacent single cells, The effect of reducing production costs is increased.

Claims (1)

A non-aqueous electrolyte secondary battery comprising a case and a lid, wherein the case and the lid are made of a metal plate having at least an outer surface coated with an insulating resin film, and the case and the lid are hermetically sealed by a tightening method A nonaqueous electrolyte secondary battery, wherein a terminal provided with an electrolyte injection hole is formed on the lid via an insulating member.