JP2001068157A - Stacked polymer electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stacked polymer electrolyte battery with high safety, capable of preventing emitting smoke.ignition even when the battery is short- circuited being nailed or crushed. SOLUTION: This polymer electrolyte battery is assembled by sealing a stacked electrode group formed by stacking positive electrodes 1 having a positive electrode mix layer 1b formed on at least one side of a positive electrode current collector 1a and negative electrodes 2 having a negative electrode mix layer 2b formed on at least one side of a negative electrode current collector 2a so as to interpose a polymer electrolyte layer between a set of electrodes into an outer case 4 containing a metal foil. A short-circuiting and heat radiation accelerating member 30 made of one metal plate is installed on at least one outside of the outer case 4, the metal plate is connected to an electrode terminal of either one electrode of the positive electrode and the negative electrode, or a short-circuiting and heat radiation accelerating unit 10 formed by arranging two metal plates through an insulating plate is installed as the short- circuiting for and heat radiation accelerating member, and two metal plates are connected respectively to an electrode terminal of the electrodes having different polarities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacked polymer electrolyte battery, and more particularly, to a stacked polymer electrolyte battery suitable for use as a power source for portable electronic devices, electric vehicles, road leveling, and the like.

[0002]

2. Description of the Related Art In a polymer electrolyte battery, the electrodes and the electrolyte can be made into a sheet shape, whereby A4
It is possible to manufacture a battery having a large area and a thin shape such as a plate and a B5 plate, and it is possible to apply the battery to various types of thin products. In particular, batteries using polymer electrolytes have excellent safety and storage properties, including liquid leakage resistance, and are thin and flexible, so that batteries that match the shape of equipment can be designed to date. Has features not found in

[0003] This polymer electrolyte battery usually uses a laminate film in which an aluminum foil is used as a core material and a heat-fusible resin film serving as an adhesive layer is disposed on the inner surface side as an outer package. Then, a thin sheet-type battery is completed by covering the laminated electrode group, in which the sheet-like electrode and the sheet-like polymer electrolyte layer are laminated, with an outer package.

In this laminated polymer electrolyte battery, when the number of laminated electrodes is small and the electric capacity or electric capacity density is low, that is, when the inherent energy is low, the above-mentioned excellent safety is secured. However, when the number of stacked electrodes increases and the electric capacity and electric capacity density increase, the safety is not sufficient.If the electrodes are short-circuited due to nail penetration or crushing, a large current flows, heat is generated, and smoke is generated. It has been found that fire, rupture and other accidents may occur.

[0005] The above-mentioned problem can be solved by causing a large current flowing at the time of short-circuit to flow out of the stacked electrode group, and simultaneously dissipating heat quickly and reducing heat storage. However, the laminated electrode group of the conventional laminated polymer electrolyte battery has a structure in which a positive electrode and a negative electrode face each other via a polymer electrolyte layer having poor heat conduction, a plurality of such layers are stacked, and a heat-fusible resin film having poor heat conduction is formed. It is thought that heat is stored inside the battery due to heat generation such as a short circuit, and the internal temperature rises greatly, leading to accidents such as smoke, ignition, and rupture due to the exterior being placed inside the battery. Can be

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and enhances the safety even when the capacity is increased by improving the battery structure. An object of the present invention is to provide a stacked polymer electrolyte battery.

[0007]

According to the present invention, there is provided a positive electrode having a positive electrode mixture layer formed on at least one surface of a positive electrode current collector, and a negative electrode mixture layer formed on at least one surface of a negative electrode current collector. A negative electrode formed, and a laminated polymer electrolyte battery in which a laminated electrode group laminated with a polymer electrolyte layer interposed therebetween is packaged with a package containing a metal foil, and at least one of the above package. This problem has been solved by providing a short-circuit formation and heat dissipation promoting member on the outside.

That is, the short-circuiting and heat-dissipating member can be externally short-circuited prior to short-circuiting inside the laminated electrode group due to nail penetration or crushing, thereby lowering the battery voltage and reducing heat generation due to a chemical reaction. it can. In addition, since the short-circuit formation and heat dissipation promoting member is provided outside the stacked electrode group, heat can be smoothly radiated by the short-circuit formation and heat dissipation promotion member. Therefore, by providing the short-circuit formation and heat dissipation promoting member, safety can be enhanced even when the capacity is increased, and a laminated polymer electrolyte battery with high safety can be provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The short-circuit formation and heat dissipation promoting members of the present invention are roughly classified into the following two. One of them is to use a plastic film on the surface of the exterior body as an insulator, and form a short-circuit and heat dissipation promotion unit between one metal plate provided outside the exterior body and the metal foil that constitutes the exterior body. A function is developed. At this time, the metal plate provided on the outside of the exterior body and the metal foil constituting the exterior body are respectively connected to the electrode terminals of electrodes having different polarities, and the nails are punctured or crushed between the inside of the laminated electrode group. An external short circuit occurs before the short circuit, thereby lowering the battery voltage and reducing heat generated by a chemical reaction. And since they are arranged outside the stacked electrode group, the heat radiation is also performed smoothly. In addition, in order to completely insulate the surface of the exterior body, a means of separately providing an insulation plate between the metal plate and the surface of the exterior body, or bonding and fixing them may be taken. Then, in order to form the short-circuit formation and heat dissipation promotion unit, the metal foil constituting the external metal plate and the exterior body preferably has a thickness of 30 μm or more. However, if those metal plates or metal foils are too thick, the electric capacity density will be reduced, and the characteristics of the laminated polymer electrolyte battery may be lost. It is preferably 200 μm or less. And
The form does not necessarily need to be non-porous, and may be a porous material such as a punching metal, a net-like or a lath-like metal, and the material is not particularly limited, Those connected to the positive electrode terminal are preferably aluminum or stainless steel, and those connected to the negative electrode terminal are preferably copper, nickel, stainless steel or the like.

As another form of the short-circuit formation and heat dissipation promoting member, there is provided a short-circuit formation and heat dissipation promotion unit in which two metal plates are arranged outside the exterior body via an insulating plate. At this time, the two metal plates of the short-circuit formation and heat dissipation promotion unit are connected to electrode terminals having different polarities, respectively, and an external short-circuit is established between the two metal plates before a short-circuit in the stacked electrode group due to nail penetration or crushing. As a result, the battery voltage is reduced, and the heat generated by the chemical reaction is reduced. And since those metal plates are arranged outside the laminated electrode group,
Heat dissipation is also performed smoothly. The metal plate of the short-circuit formation and heat dissipation promoting member preferably has a thickness of 30 μm or more in order to form a more complete short circuit. However,
If the metal plate is too thick, the electric capacity density is reduced, and the characteristics of the laminated polymer electrolyte battery may be lost. Therefore, the thickness is preferably 30 μm or more and 200 μm or less as described above. The form is not necessarily required to be non-porous, and may be porous such as punched metal, net-shaped or lath-shaped metal, and the material is not particularly limited. However, the one connected to the positive electrode terminal is preferably aluminum or stainless steel, and the one connected to the negative electrode terminal is preferably copper, nickel, stainless steel or the like.

The insulating plate may be made of any material as long as the two metal plates can be electrically isolated from each other. However, similarly to the case of the above-mentioned metal plate, the electrolysis from the polymer electrolyte layer by high-temperature storage or pressurization is performed. Considering the case of leakage of the liquid, for example, polyethylene, polypropylene, fluorine resin, polyimide, polyester with organic solvent resistance,
Plastics such as polyphenylene sulfide are preferred. The form may be any of a sheet, a film, a woven fabric, a nonwoven fabric, a net, a punch, a lath, and the like. The thickness is preferably as thin as possible if electrical insulation is possible. However, in consideration of reliability of insulation and productivity, the thickness is preferably 2 μm or more and 200 μm or less.

Further, considering the ease of manufacturing a short-circuit formation and heat dissipation promoting unit described later and the portability of the completed unit, the three members of the two metal plates and the insulating plate are integrated.
And it is preferable that it is integrated with the battery. For this purpose, a metal plate or an insulating plate with an adhesive attached to the surface may be used, or an adhesive sheet may be separately prepared to integrate the three members.

In the present invention, when producing a laminated electrode group, the positive electrode, the negative electrode, and the polymer electrolyte layer may be formed separately from each other, but at least one of the positive electrode and the negative electrode may be previously laminated to the polymer electrolyte layer. , And the electrode and the polymer electrolyte layer are preferably integrated. In this case, for example, after surrounding the electrodes in a bag-shaped porous sheet serving as a support for the polymer electrolyte layer, the whole is converted into an electrolyte containing a gelling component that is a precursor of the polymer electrolyte. Impregnation and gelation to produce an integrated product of an electrode containing a polymer electrolyte and a support, or an electrode containing a polymer electrolyte with a strip-shaped polymer electrolyte sheet containing a porous sheet support There is a case where the electrode and the polymer electrolyte layer are integrated by sandwiching. Furthermore, when the latter electrode is sandwiched between strip-shaped polymer electrolyte sheets to surround the electrodes with a polymer electrolyte layer, one strip-shaped polymer electrolyte sheet is folded at substantially the center thereof and is interposed between the polymer electrolyte sheets. There are a case where the electrode is surrounded by the polymer electrolyte layer by sandwiching the electrode, and a case where the electrode is surrounded by the polymer electrolyte layer by sandwiching the electrode between two strip-shaped polymer electrolyte sheets.

In the above case, for example, a nonwoven fabric or a microporous film is used as the porous sheet serving as a support for the polymer electrolyte. As the above nonwoven fabric,
For example, nonwoven fabrics such as polypropylene, polyethylene, polyethylene terephthalate, and polybutylene terephthalate can be used. Examples of the microporous film include microporous films of polypropylene, polyethylene, and ethylene-propylene copolymer.

Since the nonwoven fabric has a high porosity and is easily impregnated with an electrolytic solution containing a gelling component, it can be suitably used. Therefore, the case where the nonwoven fabric is used as a support will be described in detail. , Basis weight is 12g
/ M ² and a very thin nonwoven fabric having a thickness of 30 μm can be used.

Such a nonwoven fabric has a low mechanical strength such as tensile strength because of its thinness, and is difficult to handle alone. For example, the nonwoven fabric is formed into a bag and the electrodes are accommodated in the bag-shaped nonwoven fabric. By surrounding and integrating the nonwoven fabric and the electrode, the strength of the electrode can compensate for the insufficient strength of the nonwoven fabric. Also, without forming a bag shape, the strip-shaped non-woven fabric is folded almost at the center, and the electrode is sandwiched between the non-woven fabrics to surround the electrode with the non-woven fabric and integrate the electrode and the non-woven fabric. By overlapping the strip-shaped non-woven fabric, sealing one end of the non-woven fabric, sandwiching the electrode between the non-woven fabrics, surrounding the electrode with a support, and integrating the electrode and the non-woven fabric, the strength of the non-woven fabric also increases the strength of the electrode. Insufficient strength can be compensated, and workability during battery assembly can be improved, internal resistance can be reduced, and load characteristics can be improved. The case where a microporous film is used as the support is the same as the case of the nonwoven fabric.

As described above, the electrode is surrounded by a support made of a porous sheet such as a nonwoven fabric, and the electrode and the support are integrated, and the electrode is impregnated with an electrolytic solution containing a gelling component to be gelled. Thereby, the adhesion between the electrodes and the polymer electrolyte layer is better than when the electrodes and the polymer electrolyte sheet are individually gelled to form the electrode and the polymer electrolyte sheet and then laminated, and bubbles, foreign substances, and the like can be interposed between the layers. Since the amount is small, the ion transfer at the interface becomes smooth, and the reactivity between the positive electrode and the negative electrode is improved. In addition, by surrounding one of the positive electrode and the negative electrode with a support, it can also serve as a physical separator.

Then, one of the positive electrode and the negative electrode may be surrounded by the polymer electrolyte layer to integrate the electrode and the polymer electrolyte layer. At this time, the positive electrode is surrounded by the polymer electrolyte layer. When the positive electrode and the polymer electrolyte layer are integrated, the battery capacity can be larger than when the negative electrode is surrounded by the polymer electrolyte layer. That is,
Generally, it is common practice to make the negative electrode larger than the positive electrode in order to prevent dendrite generation and ensure safety.If the positive electrode is surrounded by the polymer electrolyte layer, then the negative electrode is surrounded by the polymer electrolyte layer rather than the polymer electrolyte layer. Can be reduced, and as a result, the battery capacity can be increased. Also, when the negative electrode is surrounded by the polymer electrolyte layer and the negative electrode and the polymer electrolyte layer are integrated, the interface state between the negative electrode and the polymer electrolyte layer can be made uniform. It is effective in improving the properties.

Further, if both the positive electrode and the negative electrode are surrounded by the polymer electrolyte layer, the thickness of the polymer electrolyte layer is increased, but both electrodes are integrated with the polymer electrolyte layer. Since the polarization can be reduced and the reaction at the time of charging / discharging can proceed smoothly, the load characteristics can be greatly improved.

In the present invention, the integration of the electrode and the polymer electrolyte layer means that the electrode and the polymer electrolyte layer are brought into close contact with each other without bubbles or foreign matter between the electrode and the polymer electrolyte layer. It does not mean that it is inseparably bonded.

When the support made of a porous sheet such as the above nonwoven fabric is formed into a bag shape, if the bag shape is described as, for example, a rectangular shape, one side is usually open and the other three sides are sealed. However, the sealing is not always required to be continuously performed, and the sealing may be discontinuously performed.

When accommodating the electrode in the bag-like support, it is not required that the support is made into a bag-like shape in advance, and the electrode is made into a strip-like support (for example, the length is twice the length of the electrode). As described above, a strip-shaped support having a width larger than the width of the electrode is placed on one side from the substantially central portion in the length direction, and the other width is folded back (that is, the electrode is folded back substantially at the center portion). It is sufficient that the electrodes are housed in a bag-like support by sealing the two sides in the width direction continuously or discontinuously.

In the case where two supports are overlapped and one end thereof is sealed and an electrode is sandwiched between the two supports, it is not necessary to seal the electrodes in advance. For example, it is placed on a strip-shaped support whose length is longer than the length of the electrode and whose width is wider than the width of the electrode), another strip-shaped support is placed thereon, and the support At one end, continuously or discontinuously,
What is necessary is just to make the electrode sandwiched between the support bodies.

Electrolyte for forming polymer electrolyte layer
As, for example, dimethyl carbonate, diethyl carbonate
-Carbonate, methyl ethyl carbonate, propionic acid
Methyl, ethylene carbonate, propylene carbonate
G, butylene carbonate, γ-butyrolactone, ethyl
Len glycol sulfite, 1,2-dimethoxy eta
1,3-dioxolan, tetrahydrofuran, 2-
Methyl-tetrahydrofuran, diethyl ether, etc.
In an organic solvent, for example, LiClO_Four, LiPF ₆, Li
BF_Four, LiAsF₆, LiCF_ThreeSO_Three, LiC_FourF
₉SO_Three, LiCF_ThreeCO_Two, Li_TwoC_TwoF_Four(S
O_Three)_Two, LiN (CF_ThreeSO_Two)_Two, LiC (CF_Three
SO_Two)_Three, LiC_nF_{2n + 1}SO_Three(N ≧ 2), Li
N (RfOSO_Two)_Two[Where Rf is fluoroalkyl
Prepared by dissolving inorganic ion salts such as
Is used. This inorganic ion salt in the electrolyte
The concentration is 0.5 to 1.5 mol / l, especially 0.9
~ 1.25 mol / l is preferred.

As the gelling component for converting the electrolytic solution into a polymer electrolyte, for example, polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile,
After dissolving a linear polymer such as a vinylidene fluoride-propylene hexafluoride copolymer in an electrolytic solution by heating and then cooling it to polymerize the electrolytic solution, or polymerizing with actinic rays Examples include a crosslinkable composition containing two or more possible double bonds per molecule and containing a monomer or a prepolymer as a main component.

Examples of the monomer capable of being polymerized by actinic light include monomers having two double bonds per molecule (bifunctional crosslinkable monomers) such as 1,3-butanediol diacrylate and 1,4 -Butanediol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate Acrylate, tripropylene glycol diacrylate, ethoxylated bisphenol A diacrylate, novolak diacrylate, propoxylated neopentyl glycol diacrylate Such as difunctional acrylates and the acrylate and similar difunctional methacrylates such as chromatography bets and the like.

Examples of monomers having three double bonds polymerizable by actinic rays per molecule (trifunctional crosslinking monomers) include, for example, tris (2-hydroxyethyl) isocyanurate triacrylate, trimethylolpropane triacrylate. Trifunctional acrylates such as acrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glyceryl triacrylate, caprolactone-modified trimethylolpropane acrylate, and trifunctional methacrylates similar to the above acrylates Is mentioned.

Examples of the monomer having four or more double bonds per molecule capable of being polymerized by actinic light (tetrafunctional or more crosslinkable monomer) include, for example, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated Examples include tetrafunctional or higher acrylates such as pentaerythritol tetraacrylate, dipentaerythritol hydroxypentaacrylate, dipentaerythritol hexaacrylate, and tetrafunctional or higher methacrylates similar to the above acrylates.

Further, a double bond which can be polymerized by actinic rays
Examples of the prepolymer having at least four, preferably four or more include prepolymers of urethane acrylate, epoxy acrylate, and polyester acrylate, and can be used in place of the above-mentioned monomers.

In the present invention, the monomer or prepolymer having two or more double bonds per molecule capable of being polymerized by actinic light may be used as a main component, for example, for adjusting physical properties such as gel hardness. For this purpose, a monofunctional monomer or the like can be used in combination. Further, a usage such as mixing a bifunctional monomer and a hexafunctional monomer is also possible.

In the present invention, the term "crosslinkable composition comprising a monomer or a prepolymer having two or more double bonds per molecule which can be polymerized by actinic light" as a main component means that the above-mentioned crosslinkable composition is polymerized by actinic light. Monomers or prepolymers containing only possible monomers or prepolymers having two or more double bonds per molecule, and monomers or prepolymers having two or more double bonds per molecule that can be polymerized with actinic rays with monofunctional monomers In the case where a monomer or a prepolymer having two or more double bonds per molecule capable of being polymerized by actinic rays is used in combination with a monofunctional monomer or the like as in the latter case, the crosslinkable composition Of a monomer or a prepolymer having two or more double bonds per molecule which can be polymerized by actinic light, more than 50% by weight, especially 70% by weight. Or more at a wavelength of 550 nm. Also,
The crosslinkable composition does not have to be all crosslinkable as long as the constituents thereof are not crosslinkable, as long as it is entirely crosslinkable.
Other components can be added as needed.

And, if necessary, as a polymerization initiator,
For example, benzoins, benzoin alkyl ethers, benzophenones, benzoylphenylphosphine oxides, acetophenones, thioxanthones, anthraquinones, and the like can be used. Further, alkylamines, aminoesters and the like can be used as a sensitizer of the polymerization initiator.

In the present invention, for example, ultraviolet rays (UV), electron beams (EB), visible rays, far ultraviolet rays, etc. can be used as the active rays.

[0034]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only those illustrated in the embodiments.

Example 1 First, the preparation of the positive electrode and the negative electrode used in Example 1 and the preparation of an electrolyte solution containing a gelling component will be described first.

Preparation of positive electrode: LiCoO as positive electrode active material
₂ 80 parts by weight, acetylene black 10 as a conductive additive
The mixture was uniformly mixed with 10 parts by weight of polyvinylidene fluoride as a binder using N-methylpyrrolidone as a solvent to prepare a positive electrode mixture-containing paste. This positive electrode mixture-containing paste is used as a positive electrode current collector with a thickness of 20 μm.
Is applied to both sides of the aluminum foil, dried and then calendered to adjust the thickness of the positive electrode mixture layer so that the total thickness becomes 130 μm.
The positive electrode was manufactured by cutting so as to be 0 mm × 40 mm. However, in producing the above positive electrode, the positive electrode mixture-containing paste was not applied to part of the aluminum foil, leaving an exposed portion of the aluminum foil, and connecting the exposed portion of the aluminum foil to a lead for connection with a positive electrode terminal or the like. Department. FIG. 1 schematically shows a cross-sectional view of this positive electrode. As shown in FIG. 1, the positive electrode 1 is produced by forming a positive electrode mixture layer 1b on both surfaces of a positive electrode current collector 1a, and a lead portion 1c thereof is part of an aluminum foil constituting the positive electrode current collector 1a. It is constituted by exposing the aluminum foil without applying the paste containing the positive electrode mixture to the aluminum foil.

Preparation of negative electrode A: graphite 90 as a negative electrode active material
Parts by weight and 10 parts by weight of polyvinylidene fluoride are uniformly mixed with N-methylpyrrolidone as a solvent to prepare a negative electrode mixture-containing paste, and on both surfaces of a negative electrode current collector made of a copper foil having a thickness of 10 μm. After coating and drying, calendering is performed to adjust the thickness of the negative electrode mixture layer so that the total thickness becomes 130 μm, and the area of the negative electrode mixture layer formation portion is 72 m.
The negative electrode A was prepared by cutting to a size of mx 42 mm.
In the above cutting, the lead portion to be connected to the negative electrode terminal was located at the center position in the width direction of the electrode. Also, as in the case of the above-mentioned positive electrode, in producing the negative electrode A, the negative electrode mixture-containing paste was not applied to a part of the copper foil, leaving an exposed portion of the copper foil, and connecting the exposed portion of the copper foil to the negative electrode terminal. It is a lead part for connection with such as. The negative electrode A thus manufactured is a so-called double-sided coated negative electrode in which a negative electrode mixture layer is formed on both surfaces of a negative electrode current collector. This negative electrode A
2 is schematically shown in FIG. As shown in FIG. 2, the negative electrode A is formed by forming a negative electrode mixture layer 2b on both surfaces of a negative electrode current collector 2a, and its lead portion 2c is a part of a copper foil constituting the negative electrode current collector 2a. The negative electrode mixture-containing paste is not applied to the substrate and the copper foil is exposed. In the drawing, the negative electrode A and a negative electrode B described later are used.
Both are denoted by the same reference numeral 2.

Preparation of Negative Electrode B: The same negative electrode mixture-containing paste as in the case of the above-mentioned negative electrode A was applied to one surface of a negative electrode current collector made of a copper foil having a thickness of 10 μm, dried, and then subjected to a calendering treatment. The thickness of the negative electrode mixture layer was adjusted so that the thickness became 70 μm, and the area of the negative electrode mixture layer formation portion was 72 mm × 42.
mm to obtain a negative electrode B. In preparing the negative electrode B, the negative electrode mixture-containing paste was not applied to part of the copper foil, leaving an exposed portion of the copper foil, and connecting the exposed portion of the copper foil to a lead portion for connection with a negative electrode terminal or the like. And The negative electrode B thus produced is a so-called single-sided coated negative electrode in which the negative electrode mixture layer is formed only on one side of the negative electrode current collector. FIG. 3 schematically shows a cross-sectional view of the negative electrode B. As shown in FIG. 3, the negative electrode B is the negative electrode current collector 2
The negative electrode mixture layer 2b is formed only on one surface of the substrate a.

Preparation of electrolyte solution containing gelling component: volume ratio of propylene carbonate to ethylene carbonate 1: 1
In an electrolyte prepared by dissolving 1.22 mol / l of LiPF _{6 in} a mixed solvent of
4,6-Trimethylbenzoyldiphenylphosphine oxide (trade name: Lucirin TPO, manufactured by BSF Japan Co., Ltd.) was previously added and dissolved at 2% by weight based on the monomer component, and dipentaerythritol hexaacrylate was added thereto. Ten minutes before the start of use, the mixture was added to a concentration of 6% by weight and mixed to prepare an electrolytic solution containing a gelling component. The electrolytic solution containing the gelling component is simply expressed as “gelling component-containing electrolytic solution” as described above.

The positive electrode prepared as described above is wrapped with a nonwoven fabric serving as a support for the polymer electrolyte layer, the positive electrode and the support are integrated, and the whole is impregnated with a gelling component-containing electrolyte to form a gel. Thus, a polymer electrolyte-containing positive electrode unit was obtained. The negative electrode was impregnated with a gelling component-containing electrolyte solution without being wrapped with a nonwoven fabric, and gelled to obtain a polymer electrolyte-containing negative electrode. The details of the manufacturing method are described below.

Preparation of Positive Electrode Unit Containing Polymer Electrolyte:
As a support, a polybutylene terephthalate nonwoven fabric having a thickness of 30 μm and a basis weight of 12 g / m ² [manufactured by NKK, MB1
230 (trade name)], and the length × width is 144 m
It was cut into a strip of mx 42 mm.

Then, the thickness of the cathode is 50 μm and the width is 3 mm
Was adhered from both sides to prevent short circuit and maintain the strength of the terminals. Also, after covering the entire surface of the portion of the lead portion used for connection with the positive electrode terminal with a heat release tape that loses the adhesiveness of the adhesive surface due to heat,
The positive electrode is placed on the left side of the center of the polybutylene terephthalate nonwoven fabric in the longitudinal direction, and the right side is folded back to cover the positive electrode. : Policyr, Fuji Impulse Co., Ltd.]
To form a bag of polybutylene terephthalate nonwoven fabric as a support, and the two were brought into close contact to integrate the positive electrode and the support. The positive electrode unit in which the positive electrode and the support are integrated is immersed in the gelling component-containing electrolyte for 1 minute under reduced pressure to impregnate the positive electrode unit with the gelling component-containing electrolyte, and then put in a polyethylene bag. And sealed. Next,
UV rays were radiated from both sides of the polyethylene bag at an illuminance of 1 W / cm ² for 10 seconds using an UV irradiator manufactured by Fusion UV Systems Japan Co., Ltd. to polymerize the monomer component in the electrolytic solution. The electrolyte was gelled to form a gel polymer electrolyte. The integrated body of the polymer electrolyte layer and the positive electrode is taken out of the bag, the hot peeling tape is peeled off from the bag by blowing hot air of 150 ° C. onto a portion of the lead portion used for connection with the positive electrode terminal, and the polymer electrolyte holding positive electrode unit is removed. I got

Preparation of the polymer electrolyte-containing negative electrode A: A polyimide tape having a thickness of 50 μm and a width of 3 mm was attached to both sides of the negative electrode A prepared as described above so as to extend over the negative electrode mixture layer forming portion and the lead portion. To prevent short circuits and maintain the strength of the terminals. After covering the entire surface of the portion of the lead portion used for connection with the negative electrode terminal with a heat release tape that loses the adhesiveness of the adhesive surface due to heat, the negative electrode A was decompressed into the gelled component-containing electrolytic solution. After immersion for 1 minute in the lower part to impregnate the electrolytic solution containing the gelling component, the resultant was put in a polyethylene bag and sealed. Next, ultraviolet light was applied to both sides of the polyethylene bag at a rate of 1 W using an ultraviolet irradiation device manufactured by Fusion UV Systems Japan Co., Ltd.
Irradiation was performed for 10 seconds at an illuminance of / cm ² to polymerize the monomer components in the electrolytic solution and gel the electrolytic solution to obtain a gel polymer electrolyte. The negative electrode A holding the gelled polymer electrolyte is taken out of the bag, and a hot air of 150 ° C. is blown to a portion of the lead portion used for connection with the negative electrode terminal, thereby peeling off the thermal release tape from the portion, and the polymer electrolyte-containing negative electrode. A was obtained.

Preparation of Polymer Electrolyte-Containing Negative Electrode B: A polyimide tape having a thickness of 50 μm and a width of 3 mm was attached to both sides of the negative electrode B prepared as described above so as to straddle the negative electrode mixture layer forming portion and the lead portion. To prevent short circuits and maintain the strength of the terminals. Further, after covering all surfaces of a portion of the lead portion used for connection with the negative electrode terminal with a heat release tape which loses the adhesiveness of the adhesive surface due to heat, the negative electrode B was decompressed into the gelled component-containing electrolytic solution. After immersion for 1 minute in the lower part to impregnate the electrolytic solution containing the gelling component, the resultant was put in a polyethylene bag and sealed. Next, from the outside of the polyethylene bag, ultraviolet rays were irradiated at 1 W / c by using an ultraviolet irradiation device manufactured by Fusion UV Systems Japan Co., Ltd. on the side where the negative electrode mixture layer forming portion of the negative electrode B was arranged.
Irradiation was performed for 10 seconds at an illuminance of m ² to polymerize the monomer components in the electrolyte and gel the electrolyte to form a gel polymer electrolyte. The negative electrode B holding the gel polymer electrolyte is taken out of the bag, and a hot air at 150 ° C. is blown to a portion of the lead portion used for connection with the negative electrode terminal, thereby peeling off the thermal release tape from the portion. B was obtained.

Next, five polymer electrolyte holding positive electrode units, four polymer electrolyte holding negative electrodes A, and two polymer electrolyte holding negative electrodes B prepared as described above were prepared. Unit, polymer electrolyte holding anode A, polymer electrolyte holding cathode unit, polymer electrolyte holding anode A, polymer electrolyte holding cathode unit, polymer electrolyte holding anode A, polymer electrolyte holding anode unit, polymer electrolyte holding anode A, polymer electrolyte holding cathode unit, The polymer electrolyte-holding negative electrode B was laminated in this order to obtain a laminated electrode group.
At this time, the negative electrode mixture layer forming portions of the two polymer electrolyte-holding negative electrodes B were stacked so that both faced the inside of the stacked electrode group. That is, the two negative electrode current collectors made of copper foil having a thickness of 10 μm of the polymer electrolyte holding negative electrode B were arranged so as to face the outer surface of the stacked electrode group.

Referring to this laminated electrode group and FIG. 4, the lowermost side of the laminated electrode group is provided with a polymer electrolyte holding negative electrode 20 (this polymer electrolyte holding negative electrode 20 is a negative electrode B,
That is, a polymer electrolyte is held on a single-sided coated negative electrode), and a polymer electrolyte holding positive electrode unit 10, a polymer electrolyte holding negative electrode 20, a polymer electrolyte holding positive electrode unit 10, a polymer electrolyte holding negative electrode 20, a polymer electrolyte holding negative electrode 20, Electrolyte holding positive electrode unit 10, polymer electrolyte holding negative electrode 20, polymer electrolyte holding positive electrode unit 10, polymer electrolyte holding negative electrode 20, polymer electrolyte holding positive electrode unit 10, polymer electrolyte holding negative electrode 20 (this polymer electrolyte holding negative electrode 20 is a negative electrode B, , A single-sided coated negative electrode holding a polymer electrolyte,
Except for the two outermost polymer electrolyte holding negative electrodes 20, all are stacked in the order of the negative electrode A, that is, the double-sided coated negative electrode holding the polymer electrolyte. In the drawing, a white portion around the polymer electrolyte holding positive electrode unit 10 is shown to show that a nonwoven fabric is arranged as a support around the positive electrode in producing the polymer electrolyte holding positive electrode unit 10.

An exterior body used for the exterior of the above-mentioned laminated electrode group includes:
As shown in FIG. 5, the protective film 4a is composed of a three-layer laminate film of a metal foil 4b and a heat-fusible resin film 4c. In this embodiment, a 30 μm thick nylon film is used as the protective film 4a. An aluminum foil having a thickness of 50 μm is used as the metal foil 4b, and a modified polyolefin film having a thickness of 30 μm is used as the heat-fusible resin film 4c. Prevent,
The aluminum foil blocks the passage of moisture and gas, and the modified polyolefin film acts as an adhesive layer. Two exterior bodies 4 are used for exterior of the laminated electrode group,
Both have the same configuration, but one of them is
In order to easily accommodate the stacked electrode group, it is formed in a container shape with a flange in advance, and the other is in a plate shape,
With the modified polyolefin film on the inner side,
The modified polyolefin film is disposed around the stacked electrode group, and the joint is heated to seal the modified polyolefin film by heat fusion.

FIG. 6 schematically shows a connection state between the positive electrode lead portion and the positive electrode terminal when the above-mentioned laminated electrode group is covered with this package. As shown in FIG. 6, the lead portions 1c of the positive electrode are connected in parallel and put together, connected to one end of the positive terminal 5, and the other end of the positive terminal 5 is a sealing portion between the outer bodies 4,4. It is drawn outside through 4d.

Then, after the laminated electrode group is packaged with the package, the surface of the package of the portion A in FIG. 6 (the seal portion 4d of the package 4 and the portion where the positive electrode terminal 5 is drawn out) is viewed from the surface of the package. When the ultrasonic irradiation is performed, the modified polyolefin film of the outer package is melted, and the aluminum foil in the outer package and the positive electrode terminal can be connected. In order to show this state, FIG. 7 is an enlarged view of a portion A in FIG. 6 and schematically shows a main part thereof. That is, as shown in FIG. 7, the modified polyolefin film as the heat-fusible resin film 4c in the exterior body 4 is melted, and the aluminum foil as the metal foil 4b and the positive electrode terminal 5 are connected. At the time of the above ultrasonic welding, a 947M type manufactured by Branson was used as an ultrasonic transmitter, and 4 k
Under a pressure of g / cm ² , a weld energy of 80 Joules was applied at 80% amplitude for 2 seconds, but this condition can be changed variously according to the situation.

Separately from this, a 50 μm-thick stainless steel plate punched out in the same shape as the negative electrode current collector as a metal plate constituting the short-circuit formation and heat dissipation promoting member (however, it is connected to the negative electrode terminal as an external lead of the negative electrode) For this reason, the lead portion was lengthened) and the thickness 30 punched into 72 mm x 42 mm
2 μm double-sided adhesive sheets are prepared, and the laminated electrode group is attached to the upper and lower surfaces of the outer package after the outer package, and then the stainless steel sheet is attached to the free surface of the double-sided adhesive sheet. Was pasted. FIG. 8 shows a place where the stainless steel plate as the metal plate constituting the short-circuit formation / heat dissipation promoting member 30 is arranged (only the upper surface side). FIG. 9 shows a lead portion of a negative electrode in a state where a stainless steel plate as a metal plate constituting the short-circuit formation / heat dissipation promoting member 30 is disposed outside the exterior body 4 and a metal constituting the short-circuit formation / heat dissipation promotion member. The connection state of the lead part of a board and a negative electrode terminal is shown typically. A stainless steel plate as a metal plate constituting the short-circuit formation / radiation promoting member 30 is disposed outside the exterior body 4 in accordance with the position of the negative electrode constituting the laminated electrode group, and its lead portion 30 a is connected to the negative electrode terminal 6. ing. However, in FIG. 9, the illustration of the double-sided adhesive sheet used for attaching the stainless steel plate as the metal plate constituting the short-circuit formation / radiation promoting member 30 to the exterior body 4 is omitted. The negative electrode lead 2c and the negative electrode terminal 6
Is connected as usual, and connects the aggregate of the lead portions 2c of the respective negative electrodes to one end of the negative electrode terminal 6, and the other end of the negative electrode terminal 6 is , And is drawn out through the seal portion 4d between them. In FIG. 8, reference numeral 5 denotes a positive electrode terminal, and a gap of 6 mm is provided between the positive electrode terminal 5 and the negative electrode terminal 6, and under normal conditions, they contact each other to cause a short circuit. Never.

Example 2 The procedure was the same as in Example 1 until the laminated electrode group was packaged with the package, but without connecting the positive electrode terminal as the external lead of the positive electrode and the aluminum foil in the laminate film of the package. A stacked polymer battery was assembled.

Separately from the above battery, a 50 μm-thick stainless steel plate punched in the same shape as the positive electrode current collector (however, the lead portion was lengthened for connection with the positive electrode terminal as an external lead of the positive electrode) A 50 μm-thick stainless steel plate punched in the same shape as the negative electrode current collector (however, the lead portion was lengthened for connection with the negative electrode terminal as an external lead of the negative electrode), and a thickness punched to 72 mm × 42 mm A polyphenylene sulfide film having a thickness of 30 μm is prepared, and two stainless steel plates are arranged so as to face each other with the polyphenylene sulfide film interposed therebetween to form a short-circuit formation and heat dissipation promoting unit. (Outside the body), width 6 mm and thickness 5
After fixing to the battery with a polyester adhesive tape of 0 μm, the lead of a stainless steel plate punched in the same shape as the positive electrode current collector of the short-circuit formation and heat dissipation promotion unit and the positive terminal as the external lead of the positive electrode are ultrasonically welded. , And a stainless steel plate punched into the same shape as the negative electrode and a negative electrode terminal as an external lead of the negative electrode were connected by ultrasonic welding. The location of the short-circuit formation and heat dissipation promotion unit composed of the polyphenylsulfide film and the two stainless steel plates is the same as that of the short-circuit formation and heat dissipation promotion member of the first embodiment. The accelerating unit was disposed so as to overlap the stacked electrode group and the positive electrode terminal and the negative electrode terminal connected thereto. FIG. 10 shows the positional relationship between the two stainless steel sheets and the polyphenylene sulfide film of the short-circuit formation and heat dissipation promoting unit. As shown in FIG. 10, the short-circuit formation and heat dissipation promoting unit is composed of an insulating plate (polyphenylene sulfide film in this embodiment) 31 and two metal plates (stainless steel plate in this embodiment) 32 disposed via the insulating plate 31. , 33. A stainless steel plate in which the upper metal plate 32 of the short-circuit formation and heat dissipation promotion unit as the short-circuit formation and heat dissipation promotion member 30 shown in FIG. 10 is punched in the same shape as the positive electrode current collector,
The lead portion 32a is connected to the positive electrode terminal 5 as an external lead of the positive electrode outside the battery, and the lower metal plate 33 is a stainless steel plate punched in the same shape as the negative electrode current collector,
The lead portion 33a is connected to the negative electrode terminal 6 as an external lead of the negative electrode outside the battery.

Comparative Example 1 A laminated polymer electrolyte battery was produced in the same manner as in Example 1 except that the short-circuit formation and heat dissipation promoting member as in Examples 1 and 2 was not provided.

A thermocouple was attached to the surfaces of the batteries of Examples 1 and 2 and Comparative Example 1, placed on a V block, and a stainless steel nail having a shaft portion having a diameter of 3 mm was laminated at a speed of 5 mm / sec. The group was pierced at right angles to the group, and the maximum temperature of the battery was measured. Table 1 shows the results.

[0055]

[Table 1]

As shown in Table 1, the maximum temperature of the battery of Example 1 was 135 ° C., and there was no smoking or ignition.
The maximum temperature of the battery of Example 2 was 121 ° C., and there was no smoke or ignition. On the other hand, the battery of Comparative Example 1 in which the short-circuit formation / radiation promoting member was not provided had a maximum temperature of 2
The temperature was higher than 00 ° C., which was considerably higher than 150 ° C., at which the exothermic reaction was liable to run away.

[0057]

As described above, according to the present invention, even if a short circuit occurs due to nail penetration or crushing, it is possible to provide a laminated polymer electrolyte battery that prevents smoke and ignition and has high safety.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a positive electrode used in a laminated polymer electrolyte battery according to Example 1 of the present invention.

FIG. 2 is a cross-sectional view schematically showing a negative electrode A used in the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 3 is a cross-sectional view schematically showing a negative electrode B used in the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 4 is a cross-sectional view schematically illustrating a stacked electrode group used in the stacked polymer electrolyte battery of Example 1 of the present invention.

FIG. 5 is a cross-sectional view schematically showing an outer package used for the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 6 is a cross-sectional view schematically showing a connection state between a lead portion of a positive electrode and a positive electrode terminal in the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 7 is an enlarged view of a main part of a portion A in FIG. 6;

FIG. 8 is a plan view schematically showing a place where a short-circuit formation and heat dissipation promoting member is arranged in the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 9 is a cross-sectional view of the laminated polymer electrolyte battery according to the first embodiment of the present invention in which the metal plate constituting the short-circuit formation / heat dissipation promoting member is disposed outside the outer package; It is sectional drawing which shows typically the connection state of the lead part of the metal plate which comprises a member, and a negative electrode terminal.

FIG. 10 schematically shows a positional relationship between components of a short-circuit formation and heat dissipation promotion unit as a short-circuit formation and heat dissipation promotion member arranged outside the outer package in the laminated polymer electrolyte battery of Example 2 of the present invention. In the drawing, (a) is a plan view thereof,
(B) is an enlarged view of a main part of the XX line cross-sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 1b Positive electrode mixture layer 1c Lead part 2 Negative electrode 2a Negative electrode collector 2b Negative electrode mixture layer 3 Polymer electrolyte layer 4 Outer body 4a Protective film 4b Metal foil 4c Heat-fusible resin film 4d Seal part 5 Positive electrode terminal 6 Negative electrode terminal 10 Polymer electrolyte holding positive electrode unit 20 Polymer electrolyte holding negative electrode 30 Short circuit forming and heat dissipation promoting member 30a Lead portion 31 Insulating plate 32 Metal plate 32a Lead portion 33 Metal plate 33a Lead portion

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hiroshi Yamamoto, 1-88 Ushitora, Ibaraki City, Osaka Prefecture Inside Hitachi Maxell Co., Ltd. (72) Tetsuo Kawai 1-188, Usutora, Ibaraki City, Osaka Hitachi Maxell F term (reference) 5H022 AA09 BB11 CC05 CC08 CC09 CC19 KK03 5H029 AJ03 AJ12 AK03 AL07 AM00 AM02 AM03 AM04 AM05 AM07 AM16 BJ04 BJ12 CJ22 DJ02 DJ03 DJ07 EJ01 EJ12

Claims (3)

[Claims] A positive electrode having a positive electrode mixture layer formed on at least one surface of a positive electrode current collector, and a negative electrode having a negative electrode mixture layer formed on at least one surface of a negative electrode current collector, A laminated polymer electrolyte battery in which a laminated electrode group laminated with a polymer electrolyte layer interposed therebetween is packaged with a package containing a metal foil, wherein a short circuit is formed and heat dissipation is promoted outside at least one of the package. A laminated polymer electrolyte battery comprising a member. 2. The short-circuit formation and heat dissipation promoting member provided outside the exterior body is made of one metal plate, and the metal plate is connected to an electrode terminal of one of a positive electrode and a negative electrode, and the other is connected to the other. 2. The laminated polymer electrolyte battery according to claim 1, wherein an electrode terminal of the electrode is connected to a metal foil in the outer package. 3. The short-circuit formation and heat dissipation promotion member provided outside the exterior body comprises a short-circuit formation and heat dissipation promotion unit in which two metal plates are arranged via an insulating plate. 2. The stacked polymer electrolyte battery according to claim 1, wherein each of the electrodes is connected to an electrode terminal of an electrode having a different polarity.