JP2001068156A - Stacked polymer electrolyte battery - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a laminated polymer electrolyte battery that prevents smoke and ignition even when a short circuit occurs due to nail penetration or crushing, and that is highly safe. A positive electrode formed by forming a positive electrode mixture layer on at least one surface of a positive electrode current collector, and a negative electrode formed by forming a negative electrode mixture layer on at least one surface of a negative electrode current collector, A laminated electrode group laminated with a polymer electrolyte layer interposed therebetween, in a laminated polymer electrolyte battery packaged with a package containing a metal foil, further outside the electrode of at least one outermost layer of the laminated electrode group, A short-circuit formation and heat dissipation promotion unit is provided by arranging two metal plates having a thickness of 30 μm or more with an insulator interposed therebetween, and each metal plate of the short-circuit formation and heat dissipation promotion unit is connected to a lead portion of an electrode having a different polarity. Connect with

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, in the laminated electrode group of the laminated polymer electrolyte battery, a positive electrode and a negative electrode face each other via a polymer electrolyte layer having poor heat conductivity, and a plurality of these layers are stacked, and a heat-fusible resin film having poor heat conductivity has an inner surface. Side, the heat storage inside the battery due to heat generation such as short circuit is large, the internal temperature rises greatly, and smoke, ignition,
It is thought to lead to an accident such as a rupture.

[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 in which a polymer electrolyte layer is interposed therebetween is laminated with a package including a metal foil, wherein at least one of the laminated electrode group is provided. And a short-circuit formation and heat dissipation promotion unit in which two metal plates each having a thickness of 30 μm or more are disposed via an insulator, further outside the outermost layer electrode. The object has been achieved by connecting a metal plate to leads of electrodes having different polarities.

[0008] That is, by connecting the metal plate of the short-circuit formation and heat dissipation promoting unit to the lead of the electrode, an external short-circuit occurs before a short-circuit in the laminated electrode group due to nail sticking or crushing, thereby lowering the battery voltage. As a result, heat generated by the chemical reaction can be reduced. In addition, since the metal plates are provided outside the stacked electrode group, heat can be smoothly released by the metal plates. Therefore, even if the capacity is increased by connecting the metal plate of the short-circuit formation and heat dissipation promotion unit to the lead portion of the electrode, safety can be improved, and a highly safe stacked polymer electrolyte battery can be provided. Can be.

[0009]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the material of the metal plate constituting the short-circuit formation and heat dissipation promoting unit is not particularly limited. Considering the case where liquid leakage occurs, it is preferable to use the same aluminum plate or stainless steel plate as the positive electrode current collector for the metal plate connected to the positive electrode, and use the negative electrode current collector for the metal plate connected to the negative electrode. It is preferable to use the same copper plate, nickel plate, stainless steel plate, or the like. Further, its thickness must be 30 μm or more. When the thickness is less than 30 μm, for example, a large current flowing due to a short circuit caused by a nail penetration causes the contact portion to locally generate heat and melt to form an electric path, thereby eliminating the short circuit. In some cases, the heat dissipation may not be performed, or the heat dissipation promoting action, which is another function, may be reduced, the heat dissipation may be delayed, and the heat storage may increase, leading to smoke or ignition. However,
If it is too thick, it lowers the capacitance density,
The thickness is preferably 200 μm or less because characteristics of the stacked polymer electrolyte battery may be lost. The form is not necessarily required to be non-porous, and may be, for example, a porous form such as a punching metal, a net-like or lath-like metal.

As the insulator, any material can be used as long as it can electrically isolate the two metal plates. As in the case of the above-mentioned metal plates, the material of the electrolyte from the polymer electrolyte layer by high-temperature storage or pressurization is used. Considering the case where leakage occurs, for example, plastics such as polyethylene, polypropylene, fluorine resin, polyimide, polyester, and polyphenylene sulfide having organic solvent resistance are preferable. 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, but is preferably 2 μm or more and 200 μm or less in consideration of insulation reliability and productivity.

In consideration of the ease of manufacturing a short-circuit formation and heat dissipation promotion unit described later and the portability of a completed unit,
It is preferable that the two metal plates and the insulator are integrated. For this purpose, a metal plate or an insulator 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, the connection between the metal plate of the short-circuit formation and heat dissipation promoting unit and the lead portion of the electrode means that they are electrically connected. The electrode may not be directly connected to the lead, but may be connected, for example, via a lead member between the two. However, usually, the aggregate of the lead portions of a plurality of electrodes and the lead portion of the metal plate of the short-circuit formation and heat dissipation promotion unit are overlapped, and in this state, connected to one end of the electrode terminal as an external terminal Then, the other end of the electrode terminal is drawn out to the outside through the sealing portion of the exterior body.

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, this positive electrode 1 has a positive electrode mixture layer 1 on both surfaces of a positive electrode current collector 1a.
b, and the lead portion 1c
Is formed by exposing the aluminum foil without applying the positive electrode mixture-containing paste to a part of the aluminum foil constituting the positive electrode current collector 1a.

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, a lead portion serving as a connection portion with a negative electrode terminal or the like was set at a central 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. FIG. 2 schematically shows a cross-sectional view of the negative electrode A. As shown in FIG. 2, the negative electrode A has a negative electrode mixture layer 2b on both surfaces of a negative electrode current collector 2a.
The lead portion 2c is formed by exposing the copper foil without applying the negative electrode mixture-containing paste on a part of the copper foil constituting the negative electrode current collector 2a. In the drawings, the negative electrode A and a negative electrode B described later 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 produced in this manner is a so-called single-sided coated negative electrode in which the negative electrode mixture layer is formed on only one surface of the negative electrode current collector. FIG. 3 schematically shows a cross-sectional view of the negative electrode B. As shown in FIG. 3, this negative electrode B is a 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 terminal. 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.

Preparation of short-circuit formation and heat dissipation promoting unit: thickness 50 stamped into the same shape and dimensions as a positive electrode current collector (the positive electrode current collector in this case also includes a portion serving as a lead portion).
μm aluminum plate, a 50 μm thick copper plate punched into the same shape and dimensions as the negative electrode current collector (in this case, the negative electrode current collector also includes a part to be a lead part) and a 74 mm × 44 mm insulator. A punched polyimide film having a thickness of 20 μm was prepared, and an aluminum plate and a copper plate were brought into close contact with the polyimide film at the center so as to obtain a short-circuit formation and heat dissipation promoting unit. FIG. 4 is a plan view showing the positional relationship. As shown in FIG. 4, the short-circuit formation and heat dissipation promotion unit 30 manufactured as described above is configured by disposing two metal plates 32 and 33 via an insulator 31. In FIG. 4, an aluminum plate is used for the metal plate 32 disposed on the upper side, a copper plate is used for the metal plate 33 disposed on the lower side, and a polyimide film is used for the insulator 31.

Next, five polymer electrolyte-holding positive electrode units, four polymer electrolyte-holding negative electrodes A, two polymer electrolyte-holding negative electrodes B, and two short-circuit formation and heat dissipation promoting units prepared as described above were prepared. Short-circuit formation and heat dissipation promotion unit, polymer electrolyte holding negative electrode B, polymer electrolyte holding positive electrode unit, polymer electrolyte holding negative electrode A, polymer electrolyte holding positive electrode unit, polymer electrolyte holding negative electrode A, polymer electrolyte holding positive electrode unit, polymer electrolyte holding negative electrode A, polymer A laminated electrode group was obtained by laminating an electrolyte-holding positive electrode unit, a polymer electrolyte-holding negative electrode A, a polymer electrolyte-holding positive electrode unit, a polymer electrolyte-holding negative electrode B, and a short-circuit formation / heat dissipation promoting unit in this order. At this time, the copper plates of the two sets of short-circuit formation and heat dissipation promoting units and the negative electrode mixture layers of the two negative electrodes B holding the polymer electrolyte were laminated so as to face the inside of the laminated 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 and the two aluminum plates of the short-circuit formation and heat dissipation promotion unit are all directed to the outer surface side of the stacked electrode group. Placed.

Referring to FIG. 5, a laminated electrode group in which the short-circuit formation and heat dissipation promoting unit is disposed on the outermost layer will be described. The short-circuit formation and heat dissipation promotion unit 30 is disposed on the lowermost side, and the polymer electrolyte holding negative electrode is disposed thereon. 20 (the polymer electrolyte holding negative electrode 20 is a negative electrode B, that is, a single-sided coated negative electrode holding a polymer electrolyte), a polymer electrolyte holding positive electrode unit 10, a 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, 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, that is, a And a short-circuit formation / heat dissipation promotion unit 30. 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.

FIG. 6 schematically shows a connection state between one of the metal plates of the unit for short-circuit formation and heat dissipation and the lead portion of the negative electrode and the negative electrode terminal when the laminated electrode group is externally mounted. As shown in FIG. 6, the lead portion 2c of the negative electrode and the lead portion 33a of the metal plate 33 (copper plate in this embodiment) of the short-circuit formation and heat dissipation promoting unit 30 are connected in parallel and put together. The other end of the negative electrode terminal 6 is connected to one end, and is drawn out to the outside through a seal portion between the exterior bodies 4 and 4. FIG. 7 schematically shows a connection state between the other metal plate and the lead portion of the positive electrode and the positive electrode terminal of the short-circuit forming and heat dissipation promoting unit when the above-mentioned laminated electrode group is externally packaged. As shown in FIG. 7, similarly to the case of the negative electrode side, the positive electrode lead portion 1c and the metal plate 32 (aluminum plate in this embodiment) of the short circuit forming and heat dissipation promoting unit 30 are similar to the lead portion 32a. The positive electrode terminal 5 is connected to one end of the positive electrode terminal 5 and connected to the other end. The other end of the positive electrode terminal 5 is drawn to the outside through a seal portion between the exterior bodies 4 and 4.

The outer package is composed of a three-layer laminate film of a protective film, a metal foil and a heat-fusible resin film. In this embodiment, a 30 μm-thick nylon film is used as the protective film. As the heat-fusible resin film, a modified polyolefin film having a thickness of 30 μm is used. The nylon film prevents the aluminum foil from being damaged or corroded. And the modified polyolefin film acts as an adhesive layer. The two exterior bodies 4 are used,
Both have the same configuration, but one of them is formed in a container with a flange in advance so as to easily accommodate the above-mentioned laminated electrode group, and the other is in the form of a plate, and the modified polyolefin film is coated on the inner surface. Side, and arranged around the stacked electrode group, the joint is heated to seal the modified polyolefin film by heat fusion.

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 units were not arranged on both outermost layers of the laminated electrode group.

A thermocouple was attached to the surfaces of the batteries of Example 1 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 applied to the laminated electrode group at a speed of 5 mm / sec. The battery was pierced at a right angle, and the maximum temperature of the battery was measured. Table 1 shows the results.

[0052]

[Table 1]

As shown in Table 1, the maximum temperature of the battery of Example 1 was 122 ° C., and there was no smoking or ignition. In contrast, the battery of Comparative Example 1, which did not include the short-circuit formation and heat dissipation promoting unit, had a maximum temperature of 200 ° C. or higher, which was considerably higher than 150 ° C., at which the exothermic reaction was liable to run away. Some of them caused smoke and fire.

[0054]

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.

FIGS. 4A and 4B are diagrams schematically showing the positional relationship of components of a short-circuit formation and heat dissipation promoting unit used in the laminated polymer electrolyte battery of Example 1 of the present invention, wherein FIG. 4A is a plan view thereof, and FIG.
FIG. 4 is an enlarged view of a main part of the cross-sectional view taken along line XX.

FIG. 5 is a cross-sectional view schematically illustrating a stacked electrode group in which a short-circuit formation and heat dissipation promoting unit used in the stacked polymer electrolyte battery of Example 1 of the present invention is disposed on the outermost layer.

FIG. 6 is a cross-sectional view schematically illustrating a connection state between a negative electrode lead portion and one metal plate of a short-circuit formation / heat dissipation promoting unit and a negative electrode terminal in the laminated polymer electrolyte battery of Example 1 of the present invention. .

FIG. 7 is a cross-sectional view schematically showing a connection state between the positive electrode terminal and the other metal plate of the positive electrode lead portion and the short-circuit formation and heat dissipation promoting unit in the laminated polymer electrolyte battery of Example 1 of the present invention. .

[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 2c Lead part 3 Polymer electrolyte layer 4 Outer body 5 Positive terminal 6 Negative terminal 10 Polymer electrolyte holding positive electrode unit 20 Polymer electrolyte holding negative electrode 30 Short circuit forming and heat dissipation promoting unit 31 Insulator 32 Metal plate 32a Lead 33 Metal plate 33a Lead

Continued on the front page (72) Inventor Hiroshi Yamamoto 1-1-88 Ushitora, Ibaraki-shi, Osaka Inside Hitachi Maxell Co., Ltd. (72) Inventor Tetsuo Kawai 1-188 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell stock In-house F-term (reference) 5H022 AA09 BB11 CC05 CC08 CC09 CC19 EE01 KK03 5H029 AJ03 AJ12 AK03 AL07 AM00 AM02 AM03 AM04 AM05 AM07 BJ04 BJ12 BJ22 BJ27 CJ05 CJ22 DJ02 DJ05 DJ07 EJ01 EJ12 HJ04

Claims (1)

[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 including a metal foil, wherein at least one outermost layer electrode of the laminated electrode group is further provided. On the outside, a short-circuit formation and heat dissipation promotion unit is provided by arranging two metal plates having a thickness of 30 μm or more via an insulator, and each metal plate of the short-circuit formation and heat dissipation promotion unit is provided with an electrode having a different polarity. A stacked polymer electrolyte battery, wherein the battery is connected to a lead portion.