JPH05326019A - Battery - Google Patents

Abstract

PURPOSE:To provide a small-sized and light-weighted battery having high performance and high energy density by forming a complex positive electrode made of an ion conductive high molecular compound and positive electrode active material, a negative electrode, and ion conductive electrolyte made of high molecular material through irradiation by radial rays. CONSTITUTION:A battery is composed of a complex positive electrode 2, a negative electrode and electrolyte 3. The positive electrode 2 is composed of an ion conductive high molecular compound made of high molecular material in which at least one kind of ionic compound is dissolved, and electrochemical material. The electrolyte 3 is formed of an ion conductive high molecular compound made of high molecular material in which at least an ionic compound is dissolved. These high molecular compounds have polyether structures, and are formed through the irradiation of ionizing radiation. The negative electrode is generally made of alkali metal. The negative electrode is desirably to be a complex negative electrode 4 having the same structure as that of the positive electrode 2, and is further desirably to be formed through the irradiation of the ionizing readial rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery that operates at ambient temperature, and more particularly to improvements in electrolytes, positive electrodes and negative electrodes, and improvements in their manufacturing method.

[0002]

2. Description of the Related Art With the recent microelectronics of electronic equipment, batteries used as a power source for memory backup of electronic equipment are housed in the electronic equipment or integrated with electronic elements and circuits. As a result, there is a demand for miniaturization, weight reduction, and thinning of such a battery, and further, a battery having a high energy density. Therefore, as a battery that replaces the lead battery and nickel-cadmium battery that have been conventionally used, a battery using a non-aqueous electrolyte that can be further reduced in size and weight has been receiving attention. However, since this battery does not satisfy practical physical properties such as cycle characteristics and self-discharge characteristics of the electrode active material,
Many research institutes are still studying to improve them.

The present inventors have studied batteries that are smaller, lighter and have higher energy density. However,
When such a battery is used as a secondary battery, there is a problem that the use of metallic lithium is restricted due to problems such as generation of dendrite of lithium and passivation of the interface. Therefore, researches on lithium metal-containing alloys typified by lithium-aluminum, lithium-lead, and lithium-tin alloys have been actively conducted. As represented by lithium-aluminum alloys, since these alloys have low strength, the cycle characteristics of the battery are not improved because the electrodes are cracked or miniaturized due to repeated charging / discharging.

Further, as another method for suppressing the production of lithium dendrite, investigations such as selection of electrolyte salt and improvement of separator have been attempted. Among these, with respect to the separator, it has been attempted to suppress the generation of lithium dendrite by laminating polypropylene non-woven fabric and glass fiber non-woven fabric, which have been conventionally used as a separator, but the essential solution has not been reached. ..

Therefore, as the above-mentioned electrode active material, a material utilizing intercalation of a layered compound or a doping phenomenon has been particularly studied. Since these theoretically do not cause a complicated chemical reaction during the electrochemical reaction during battery charging / discharging, extremely excellent charge / discharge cycle performance is expected.

Further, in order to solve the problems such as the cycle characteristics and the self-discharge characteristics of the electrode active material, the use of a carbonaceous material as the electrode active material has been studied. The characteristics of the carbonaceous material are high doping capacity, low self-discharge rate, excellent cycle characteristics, etc., and the most notable characteristic is that it has a base potential extremely close to that of metallic lithium.

On the other hand, conventionally, as an electrolyte such as a battery utilizing an electrochemical reaction or an electrochemical device other than the battery, that is, an electric double layer capacitor, an electrochromic element or the like,
Generally, liquid electrolytes, particularly those in which an ionic compound is dissolved in an organic electrolytic solution have been used. Since this liquid electrolyte easily causes liquid leakage to the outside of the component, elution of electrode material, volatilization, etc., problems such as long-term reliability and scattering of the electrolytic solution in the sealing step have been problems.

Therefore, in order to improve the leakage resistance and the long-term storage stability, an ion-conductive polymer compound having high ion-conductivity has been studied, and further research has been conducted as one of means for solving the above problems. It is being advanced.

The ion-conducting polymer compounds currently under study are homopolymer or copolymer linear polymers having ethylene oxide as a basic unit, network cross-linking polymers, comb polymers and the like. For the purpose of increasing the ionic conductivity at low temperatures, it has been proposed and implemented to prevent crystallization by using a crosslinked polymer or a comb polymer. In particular, an ion conductive polymer compound using a reticulated crosslinked polymer is useful because it has high mechanical strength and good ionic conductivity at low temperatures.

Hitherto, as a method for crosslinking a homopolymer or a copolymer having ethylene oxide as a basic unit, urethane crosslinking, ester crosslinking, or radical polymerization of acrylic acid ester or methacrylic acid ester has been carried out. However, these cross-linking methods have a urethane bond or an ester bond, and thus have problems in chemical stability and electrochemical stability. In particular, when lithium metal is used for the negative electrode in the ion-conductive polymer compound having a urethane bond, the polymer compound easily reacts with lithium, and the potential stability on the basis of metal lithium potential is poor. Furthermore, when a lithium primary battery is manufactured using the above ion-conductive polymer compound, the battery capacity significantly decreases after storage at high temperature for a long time (for example, after storage at 60 ° C. for 3 months) (about 50% of the initial discharge capacity).
%) Was obtained.

When the above ion-conductive polymer compound is applied to the electrolyte of an electrochemical device, it is necessary to make the electrolyte into a thin film in order to lower the internal resistance. With the ion conductive polymer compound, a uniform thin film can be easily processed into an arbitrary shape. Such methods include
For example, (a) a method of casting a solution of an ion-conductive polymer compound to evaporate and remove the solvent, (b) a method of coating a polymerizable polymerizable monomer or macromer on a substrate and heating polymerization, or (c) an actinic ray. There is a method of curing by irradiation. Among these methods, the heat polymerization method is a method that has been mainly used conventionally since it can be easily carried out. However, in the heat polymerization method, it is difficult to improve the production rate because the heat polymerization time becomes very long, a temperature gradient is likely to occur in the heating furnace, and the heating furnace and ancillary materials are used because the heating is performed in an inert gas atmosphere. There was a problem that the equipment became large.

In addition to the above problems, the curing method by heat polymerization has a problem that the crosslinked network has an irregular structure because the polymerization inhibitor is biased in the ion conductive polymer compound composition liquid. there were. This problem has become more serious than the above-mentioned problems of manufacturing speed and equipment.

On the other hand, in the method of curing by using ultraviolet rays as active rays, the curing time can be shortened by adding an ultraviolet irradiation lamp, so that it is superior to the heat polymerization method, but it is in an inert gas atmosphere area. The problem of the need to upsize the lamp and the problem of heat generated from the UV irradiation lamp were serious. As a result, in addition to the ultraviolet irradiation equipment, the increase in the size of the auxiliary equipment has been a problem.

[0014]

In view of the above problems of the prior art, the present invention aims at improving battery characteristics and producing a high-performance electrode in a battery using an ion-conductive polymer compound. It is an object of the present invention to provide a battery which has extremely high workability, does not worry about liquid leakage to the outside, and has high long-term reliability and safety.

Another object of the present invention is to provide a small and lightweight battery having high performance and high energy density.

[0016]

[Means for Solving the Problems] In order to solve the above problems,
The battery of the present invention comprises the following (A), (B) and (C); (a) An ion conductive polymer compound comprising a polymer substance in which at least one ionic compound is dissolved, A composite positive electrode (A); (b) negative electrode (B); and (c) comprising a polymer compound having a polyether structure and at least ionic conductivity, and an electrochemically active substance; An electrolyte composed of an ion-conducting polymer compound composed of a polymer substance in which a certain ionic compound is dissolved, the polymer compound having a polyether structure and having ion conductivity ( C) ;, wherein the polymer substance constituting the composite positive electrode (A) and / or the electrolyte (C) is formed by irradiation with ionizing radiation.

The negative electrode used in the battery of the present invention is generally an alkali metal. The preferred alkali metal is lithium metal. However, in the battery of the present invention, more preferably, the negative electrode (B) is an ion-conducting polymer compound composed of a polymer compound in which at least one ionic compound is dissolved. Is a composite negative electrode (D) comprising a polyether structure and at least ionic conductivity, and an electrochemically active substance. The polymer substance forming the composite negative electrode (D) is preferably formed by irradiation with ionizing radiation.

In the battery of the present invention, the composite positive electrode (A)
The polymer substance constituting the, the polymer substance constituting the composite negative electrode (D), and the polymer substance constituting the electrolyte (C) may be the same kind or different kinds. That is,
The polymeric substances that make up these three members may all be the same substance, and the polymeric substances that make up the two members may be the same and the polymeric substances that make up the other member may be different. Alternatively, the polymer substances forming the three members may be different from each other. In the battery of the present invention, preferably, the polymeric substances constituting these three members are all the same substance.

The polymeric substance used in the present invention is
It has a polyether structure and has at least ionic conductivity. A general organic compound used as a raw material for such a polymer substance, that is, a polymerizable monomer is
It is a polyether obtained by reacting an active hydrogen-containing compound with glycidyl ethers.

Examples of the active hydrogen-containing compound include:
Polyhydric alcohols such as methanol, ethanol, ethylene glycol, propylene glycol, 1,4-butanediol, glycerin, trimethylolpropane, and polyglycerin; amines such as butylamine, 2-ethylhexylamine, ethylenediamine, hexamethylenediamine, and triethylenetetramine. Compounds; phenolic active hydrogen compounds such as bisphenol-A, bisphenol-S, bisphenol-F and hydroquinone; compounds having different active hydrogen-containing groups in one molecule such as monoethanolamine and diethanolamine.

On the other hand, examples of the glycidyl ethers to be reacted with the active hydrogen-containing compound are represented by the following formula. (However, n represents an integer of 0 to 10, R ₁ represents an alkyl group, an alkenyl group, an aryl group or an alkylaryl group having 1 to 20 carbon atoms, and X represents a halogen element).

In addition to the above glycidyl ethers, an alicyclic epoxy compound represented by the following formula: (However, R ₂ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group or an alkylaryl group).

As mentioned above, examples of the polymerizable monomer having an epoxy group obtained by reacting an active hydrogen-containing compound with glycidyl ethers include: bisphenol-A type, bisphenol-S type, bisphenol-F.
Type, monoglycidyl ether or diglycidyl ether; bisphenol-A type, bisphenol-S type or bisphenol-F type organic compound having one or more alicyclic epoxy groups; novolak type monoglycidyl ether or diglycidyl ether A novolac organic compound having one or more alicyclic epoxy groups;
However, the present invention is not limited to these substances. The polymerizable monomer may be used alone or as a mixture of two or more kinds.

Preferably, the polymer substance is formed by cationic ring-opening polymerization of an epoxy group in a polymerizable monomer having an epoxy group. Therefore, it is possible to provide a polymer substance having excellent ionic conductivity and being chemically and electrochemically stable. More preferably, the polymer substance is a polymer of a polymerizable monomer having two or more epoxy groups and has a network structure. Such polymerization may be cationic ring-opening polymerization. Also,
Preferably, the polymer substance is a polymer mixture obtained by polymerizing a polymerizable monomer having one epoxy group and a polymerizable monomer having two or more epoxy groups, and has a network structure. Such polymerization may be cationic ring-opening polymerization. An ion-conductive compound derived from such a polymer substance has excellent ion conductivity and is chemically and electrochemically stable.

The polymerization initiator used in the cationic ring-opening polymerization includes a) iodonium salt (Ar ₂ IPF ₆ : Ar represents an aryl group); and b) the cation moiety of the iodonium salt is Ar ₂ N ^+. , Ar
₂ S ⁺ , Ar ₂ SArAr ⁺ , Ar ₂ SArSArSAr ₂ ⁺
C) those in which the anion portion of the iodonium salt is substituted with hexafluoroarsenite ion, perchlorate ion, trifluoromethanesulfonate ion, tetrafluoroborate ion, etc .; d) Any combination of the above b) and c);
It is not limited to these.

Next, the polymer substance thus obtained is mixed with an ionic compound to prepare an ion-conductive polymer compound. In the present invention, the ionic compound contained in the polymer substance constituting the composite positive electrode (A), the ionic compound contained in the polymer substance constituting the composite negative electrode (D), and the high component constituting the electrolyte (C). The ionic compounds contained in the molecular substance may be of the same kind or of different kinds. That is, the ionic compounds contained in these three members may all be the same substance, the ionic compounds contained in the two members are the same, and the ionic compounds contained in the other member are different. Or the ionic compounds contained in the three members may be different from each other. In the battery of the present invention, preferably, the ionic compounds contained in these three members are the same substance.

Useful as ionic compounds in the present invention are: a) inorganic ionic salts containing one of lithium, sodium or potassium, such as lithium perchlorate, lithium thiocyanate, lithium tetrafluoroborate, hexavalent Lithium fluoroarsenite, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium trifluoroacetate, sodium iodide, sodium thiocyanate, sodium bromide, potassium thiocyanate, etc .; b) quaternary ammonium salt, For example, tetramethylammonium tetrafluoroborate, tetramethylammonium bromide,
Tetraethylammonium perchlorate, tetraethylammonium iodide, tetrapropylammonium bromide, tetra-n-butylammonium perchlorate, tetra-n-butylammonium iodide, tetraethylammonium maleate, tetraethylammonium benzoate, tetraethylammonium phthalate, etc .; Or c) organic ionic salts, such as lithium stearyl sulfonate, sodium octyl sulfonate, lithium dodecyl sulfonate, and the like. In the present invention, these ionic compounds may be used in combination of two or more kinds.

The mixing ratio of the ionic compound to the polymer substance can be adjusted appropriately according to the purpose. If the blending ratio of the ionic compound is too high, an excess ionic compound, for example, an inorganic ionic salt does not dissociate and is simply mixed in the polymer substance, resulting in a decrease in ionic conductivity. .. In addition, the mixing ratio of the ionic compound to the polymer substance varies depending on the kind of the electrode active material. For example, in a battery utilizing intercalation of a layered compound, a blending ratio in the vicinity of the maximum conductivity of the electrolyte is preferable. On the other hand, in a battery that uses a conductive polymer that utilizes a doping phenomenon as an electrode active material, it is necessary that the ion concentration in the electrolyte be able to cope with changes due to charge and discharge.

The method of incorporating the ionic compound into the polymer substance is not particularly limited, and any known method can be used. For example, a method of dissolving an ionic compound in an organic solvent such as methyl ethyl ketone or tetrahydrofuran, impregnating a polymer substance with the ionic compound, uniformly mixing in the polymer substance, and then removing the organic solvent by vacuum pressure reduction. There is. There is also a method in which the polymerizable monomer and the ionic compound are mixed and then the polymerizable monomer is polymerized (preferably, cationic ring-opening polymerization).

In the present invention, the ion conductive polymer compound may contain a substance capable of dissolving the ionic compound contained in the ion conductive polymer compound. By including such a substance, the conductivity can be remarkably improved without changing the basic skeleton of the ion conductive polymer compound.

Examples of the substance capable of dissolving the ionic compound include a) cyclic carbonic acid esters such as propylene carbonate and ethylene carbonate, b) cyclic esters such as γ-butyrolactone, and c) ethers such as tetrahydrofuran or Derivatives thereof, 1,3-dioxane, 1,2-dimethoxyethane, methyl diglyme, etc. 2) Nitriles, such as acetonitrile, benzonitrile, etc.) Dioxolane or its derivatives, sulfolane or its derivatives, etc., but are not limited to these. It is not something that will be done. These substances can be used alone or as a mixture of two or more. Further, the blending ratio and blending method of the polymeric substances of these substances can be appropriately selected according to the purpose and the like.

Examples of the positive electrode active material that can be used in the composite positive electrode (A) of the present invention include the following battery electrode materials: (a) Group I metal compounds such as cuprous oxide, cupric oxide, and oxides. Silver, copper sulfide, copper sulfate, etc .; b) Group V metal compound, for example, divanadium pentoxide, V
₆ O ₁₂ , VO _x , diniobium pentoxide, bismuth trioxide, diantimony trioxide, etc. c) Group VI compounds such as chromium trioxide, dichromium trioxide, molybdenum trioxide, molybdenum disulfide, tungsten trioxide , Selenium dioxide, etc .; d) Group VIII metal compounds, such as iron monoxide, diiron trioxide, triiron tetraoxide, dinickel trioxide, nickel monoxide,
Cobalt monoxide, cobalt trioxide, etc .; e) General formula Li _X MX _V or Li _X MN _V X ₂ (M and N are I
To a metal of Group VIII; X represents a chalcogen such as oxygen or sulfur), for example, a lithium-cobalt complex oxide, a lithium-manganese complex oxide, etc .; Examples thereof include, but are not limited to, polypyrrole, polyaniline, polyparaphenylene, polyacetylene, polyacene-based materials and the like;

On the other hand, examples of the negative electrode active material that can be used in the composite negative electrode (D) of the present invention include the following battery electrode materials: a) Carbonaceous materials such as carbon, for example, carbonaceous materials,
As a result of analysis by X-ray diffraction, lattice spacing (d002) 3.35 to 3.40
Angstrom-crystallite size in the a-axis direction La 200 angstroms or more-crystallite size in the c-axis direction Lc 200 angstroms or more-True density 2.00 to 2.25
g / cm ³ or carbon powder (average particle size 15 μm or less) or carbon powder obtained by firing an anisotropic pitch at a temperature of 2000 ° C. or higher; (b) lithium metal or the like; c) lithium alloy, for example, Lithium-aluminum,
Lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, wood alloy, etc .;
It is not limited to these, or those used as the positive electrode active material may be used as the negative electrode active material.

As a method for producing the composite positive electrode (A) and the composite negative electrode (D) of the present invention, any known method can be used. As a preferable production method, a composition liquid constituting the composite positive electrode (A) or the composite negative electrode (D) is applied to the surface of the current collector plate, and then polymerized and cured by ionizing radiation.
For such a coating method, for example, roller coating such as an applicator roll, screen coating,
It is desirable to apply a uniform thickness using a means such as a doctor blade method, spin coating, or a bar coder, but it is not limited to these methods. In addition,
When these means are used, it is possible to increase the actual surface area of the electrochemically active material that contacts the electrolyte layer and the current collector.

In this case, if necessary, carbon such as graphite, carbon black, acetylene black (the carbon here has completely different characteristics from the carbon that can be used as the above-mentioned negative electrode active material). ,), A metal powder, and a conductive material such as a conductive metal oxide may be mixed in the composite positive electrode and / or the composite negative electrode to improve the electron conductivity. Further, when producing the composite positive electrode and the composite negative electrode of the present invention, several kinds of dispersants and dispersion media may be added to the dispersion system in order to obtain a uniform mixed dispersion system.
Further, if necessary, a thickener, a bulking agent, an adhesion aid, etc. can be added to the dispersion system as appropriate.

In the battery of the present invention, does the electrolyte be placed between the composite positive electrode (A) and the negative electrode (B) or the composite negative electrode (D) in the form of a sheet of the above ion-conductive polymer compound? Alternatively, the surface of the composite positive electrode (A), the surface of the negative electrode (B), or the surface of the composite negative electrode (D) is coated with the above-mentioned ion conductive polymer compound composition and cured.

As the method for applying the ion-conductive polymer of the present invention, any known method can be used as long as it can be applied uniformly. Such methods include, but are not limited to, roller coating of applicator rolls, screen coating, doctor blade method, spin coating, bar coder, and the like.

In the present invention, as the positive electrode current collector plate,
Materials such as aluminum, stainless steel, titanium, and copper are preferable. On the other hand, the negative electrode current collector plate is preferably made of a material such as stainless steel, iron, nickel or copper. However, in the present invention, the material of the collector plate is not limited to the above substances.

In the present invention, the polymer substance is preferably formed by irradiation with ionizing radiation. By forming these members by irradiation of ionizing radiation, it becomes possible to manufacture these members at a low temperature in a short time. As a result, the workability is remarkably improved and it becomes possible to achieve uniform quality, as compared with the conventionally used methods such as the thermal method and the method using ultraviolet irradiation. Furthermore, since the degree of crosslinking of the polymer substance can be easily controlled by forming the polymer substance by irradiation of ionizing radiation, it is possible to prepare an electrochemically optimal electrode or electrolyte. ..

The ionizing radiation used in the present invention includes γ rays, X rays, electron rays, neutron rays and the like. The method of using these ionizing radiations in cross-linking the polymerizable monomer to form a polymer compound is very efficient. In the present invention, ionizing radiation is used for all of the polymer substance forming the composite positive electrode (A), the polymer substance forming the composite negative electrode (D), and the polymer substance forming the electrolyte (C). Alternatively, any one or two of the polymer substances forming these three members may be formed by a thermal method or irradiation with visible light or ultraviolet light.

When an electron beam is used as the ionizing radiation, the electron beam is irradiated with an accelerating voltage of at least 100 kV.

Hereinafter, details of the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[0043]

Example 1 1) A composite positive electrode (A) was produced according to the following procedure.
LiCoO ₂ as the positive electrode active material of the battery and acetylene black as the conductive agent were mixed at a weight ratio of 85:15 to obtain a mixture (a).

On the other hand, the polymerizable monomers I and
To the mixture 10 parts by weight of II, tetrafluoroborate lithium 1 part by weight, an iodonium salt _{(C 6 H 5) 2 IPF} 6 0.05 part by weight, 10 parts by weight of 1,2-dimethoxyethane, and γ- butyrolactone 10 The parts by weight were mixed to obtain a mixture (b). Here, the polymerizable monomers I and II are I: II = 1: 1.
Mixed in a weight ratio of 2.

[0045] Mixtures (a) and (b) in a dry inert gas atmosphere
Were mixed in a weight ratio of 10: 3 to obtain a mixture (c).

The mixture (c) was cast on a current collector having a conductive carbon film formed on the surface of a positive electrode current collector plate made of aluminum. Then, the mixture (c) was irradiated with an electron beam in a dry inert gas atmosphere to cure it. The accelerating voltage of the electron beam was 250 kV, and the electron dose was 12 Mrad. The thickness of the composite positive electrode (A) coating formed on the stainless current collector was 6
It was 0 μm.

2) Next, a composite negative electrode (D) was produced according to the following procedure. Carbon powder as a negative electrode active material of the battery was mixed with 10 parts by weight of the mixture of the polymerizable monomers I and II to obtain a mixture (d). The mixing weight ratio of the polymerizable monomers I and II is the same as above.

On the other hand, 1 part by weight of lithium tetrafluoroborate,
10 parts by weight of 1,2-dimethoxyethane and 10 parts by weight of γ-butyrolactone were mixed to obtain a mixture (e).

Mixtures (d) and (e) were mixed in a dry inert gas atmosphere at a weight ratio of 7: 3 to obtain mixture (f).

The mixture (f) was cast on a current collector having a conductive carbon film formed on the surface of a negative electrode current collector plate made of stainless steel. Then, the mixture (f) was irradiated with an electron beam in a dry inert gas atmosphere to cure it. The accelerating voltage of the electron beam was 250 kV, and the electron dose was 15 Mrad. As a result, the film thickness of the composite negative electrode (D) formed on the stainless current collector was 30 μm.

Next, an electrolyte layer (C) was formed on the composite negative electrode (D) by the following procedure. 30 parts by weight of the mixture of the polymerizable monomers I and II, 6 parts by weight of lithium tetrafluoroborate, 32 parts by weight of 1,2-dimethoxyethane, and 32 parts by weight of γ-butyrolactone are mixed to obtain a mixture (g). It was The mixing weight ratio of the polymerizable monomers I and II is the same as above.

The mixture (g) was cast on the composite negative electrode (D), and the mixture (g) was irradiated with an electron beam in a dry inert gas atmosphere to cure the mixture. The accelerating voltage of the electron beam was 250 kV, and the electron dose was 8 Mrad. Electrolyte layer (C) obtained as a result
Had a thickness of 25 μm.

3) Electrolyte (C) / obtained in 2) above
By bringing the composite negative electrode (D) / negative electrode current collector into contact with the composite positive electrode (A) / positive electrode current collector obtained in 1) above,
A sheet battery was assembled. The electrode area of the sheet-shaped battery of the present invention can be variously changed depending on the manufacturing process, but in the present example, the electrode area was 100 cm ² .

FIG. 1 is a sectional view showing another embodiment of the sheet battery of the present invention. In FIG. 1, 1 represents a positive electrode current collector plate made of aluminum, and 2 represents a composite positive electrode (A).
For the positive electrode, LiCoO ₂ was used as the positive electrode active material, and acetylene black was used as the conductive agent. Then, a mixture (h) composed of a mixture of polymerizable monomers I and II, lithium tetrafluoroborate, 1,2-dimethoxyethane and γ-butyrolactone was used as a binder. Further, 3 is an electrolyte layer (C) made of the ion conductive polymer compound of the present invention. Reference numeral 4 represents a composite negative electrode (D) in which carbon powder was used as the negative electrode active material and the polymerizable monomer was used as the binder. Further, 5 is a negative electrode current collector plate made of stainless steel, and this negative electrode current collector plate also serves as an exterior. 6 is a sealing material made of modified polypropylene.

[0055]

[Comparative Example 1] A sheet-shaped battery including a composite positive electrode, a composite negative electrode, and an electrolyte layer was prepared by the following procedure.

1) A composite positive electrode was prepared according to the following procedure. LiCoO ₂ as the positive electrode active material of the battery and acetylene black as the conductive agent were mixed at a weight ratio of 85:15 to obtain a mixture (a ′).

On the other hand, 10 parts by weight of a mixture of polyethylene glycol diacrylate (molecular weight: 5000) and polyethylene glycol monoacrylate (molecular weight: 400), 1 part by weight of lithium tetrafluoroborate and 10 parts by weight of 1,2-dimethoxyethane. , And 10 parts by weight of γ-butyrolactone were mixed to obtain a mixture (b ′). Here, polyethylene glycol diacrylate and polyethylene glycol monoacrylate were mixed in a weight ratio of 6: 4.

Mixtures (a ') and (b') were mixed at a weight ratio of 10: 3 in a dry inert gas atmosphere to obtain mixture (c ').

The mixture (c ') was cast on a current collector having a conductive carbon film formed on the surface of a positive electrode current collector plate made of aluminum. Then, the mixture (c ′) was irradiated with an electron beam in a dry inert gas atmosphere to cure it. The acceleration voltage of the electron beam is 250 kV,
The electron dose was 12 Mrad. The thickness of the composite positive electrode film formed on the stainless current collector is 60
was μm.

2) Next, a composite negative electrode was produced according to the following procedure. Carbon powder as a negative electrode active material of the battery was mixed with 10 parts by weight of a mixture of the above polyethylene glycol diacrylate and polyethylene glycol monoacrylate to obtain a mixture (d ′). The mixing weight ratio of polyethylene glycol diacrylate and polyethylene glycol monoacrylate is the same as above.

On the other hand, 1 part by weight of lithium tetrafluoroborate,
10 parts by weight of 1,2-dimethoxyethane and 10 parts by weight of γ-butyrolactone were mixed to obtain a mixture (e ′).

Mixtures (d ') and (e') in a dry inert gas atmosphere in a weight ratio of 7: 3,
A mixture (f ') was obtained.

The mixture (f ') was cast on a current collector having a conductive carbon film formed on the surface of a negative electrode current collector plate made of stainless steel. Then, the mixture (f ') was irradiated with an electron beam in a dry inert gas atmosphere to cure it. The acceleration voltage of the electron beam is 250 kV,
The electron dose was 10 Mrad. as a result,
The film thickness of the composite negative electrode formed on the stainless current collector was 30 μm.

Next, an electrolyte layer was formed on the above composite negative electrode by the following procedure. 30 parts by weight of the mixture of polyethylene glycol diacrylate and polyethylene glycol monoacrylate, 6 parts by weight of lithium tetrafluoroborate, 32 parts by weight of 1,2-dimethoxyethane, and 32 parts by weight of γ-butyrolactone are mixed to obtain a mixture (g. Got '). The mixing weight ratio of polyethylene glycol diacrylate and polyethylene glycol monoacrylate is the same as above.

The mixture (g ') was cast on the above composite negative electrode, and the mixture (g') was irradiated with an electron beam in a dry inert gas atmosphere to cure it. The accelerating voltage of the electron beam was 250 kV, and the electron dose was 8 Mrad. The thickness of the resulting electrolyte layer was 25 μm.

3) A sheet-shaped battery was assembled by bringing the electrolyte / composite negative electrode / negative electrode current collector obtained in 2) above into contact with the composite positive electrode / positive electrode current collector obtained in 1) above. .. The electrode area was 100 cm ² .

[0067]

[Charge / Discharge Cycle Characteristics] Using the sheet-shaped batteries of Example 1 and Comparative Example 1 above, a charge / discharge cycle test was conducted at 25 ° C. and a constant current of 50 μA / cm ² . The test conditions were a charge end voltage of 4.1V and a discharge end voltage of 2.7V. The results are shown in FIG. 2 as the relationship between the number of charge / discharge cycles and the battery capacity. As is clear from FIG. 2, the sheet-shaped battery of the present invention showed excellent charge-discharge cycle characteristics as compared with the comparative example and the sheet-shaped battery, the battery capacity did not decrease even after repeated charging and discharging.

[0068]

Example 2 1) A composite positive electrode (A) was produced according to the following procedure.
Example 1 was the same as Example 1 except that LiCoO ₂ was used as the positive electrode active material of the battery, acetylene black was used as the conductive agent, and the mixture of the polymerizable monomers shown below was used. Here, the polymerizable monomers I and III were mixed in a weight ratio of I: III = 1: 2.

[0069] The thickness of the composite positive electrode film formed on the stainless current collector is 6
It was 0 μm.

2) Next, a composite negative electrode (D) was produced according to the following procedure. Example 1 was the same as Example 1 except that carbon powder was used as the negative electrode active material of the battery and the same polymerizable monomer as in 1) was used. The thickness of the composite negative electrode (D) formed on the stainless current collector was 30 μm.

Next, according to the following procedure, an electrolyte layer (C) was formed on the composite negative electrode (D). The above-mentioned polymerizability,
A mixture of 30 parts by weight of a mixture of monomers I and III, 6 parts by weight of lithium tetrafluoroborate, 32 parts by weight of 1,2-dimethoxyethane, and 32 parts by weight of γ-butyrolactone was mixed on the composite negative electrode (D). It was cast and irradiated with an electron beam in a dry inert gas atmosphere to cure it. The accelerating voltage of the electron beam was 250 kV, and the electron dose was 8 Mrad. The thickness of the electrolyte layer (C) obtained as a result was 25 μm.

3) Contacting the electrolyte (C) / composite negative electrode (D) / negative electrode current collector obtained in 2) with the composite positive electrode (A) / positive electrode current collector obtained in 1) above. Thus, the sheet-shaped battery of the present invention was produced.

[0073]

As is apparent from the above description, a composite electrode (A) composed of an ion conductive polymer compound composed of a polymer material in which at least one ionic compound is dissolved and an electrochemical positive electrode active material ): Negative electrode (B): and
By forming the ion-conductive electrolyte (C) composed of a polymer substance in which at least one ionic compound is dissolved by irradiation with ionizing radiation, it becomes possible to treat at low temperature in a short time, Compared with the conventional thermal method, the workability has been remarkably improved and the quality can be made uniform.

Further, the ion conductive polymer compound is
Since the epoxy group of the polymerizable monomer having an epoxy group is composed of a polymer obtained by cationic ring-opening polymerization, it is possible to provide an ion conductive compound having excellent ion conductivity and being chemically and electrochemically stable. Possible, and thus
It has become possible to provide a battery with high reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sheet-shaped battery of the present invention.

FIG. 2 is a diagram showing the relationship between the number of charge / discharge cycles and the battery capacity of the sheet-shaped battery of Example 1 and the sheet-shaped battery of Comparative Example 1.

[Explanation of symbols]

 1 Positive Electrode Current Collector 2 Composite Positive Electrode 3 Electrolyte 4 Composite Negative Electrode 5 Negative Current Collector 6 Sealing Material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Issei Takeda 6-6 Josaimachi, Takatsuki City, Osaka Prefecture Yuasa Battery Co., Ltd. (72) Inventor Shuichi Ido 6-6 Josaimachi, Takatsuki City, Osaka Yuasa Battery Stock company

Claims (8)

[Claims] 1. The following (A), (B) and (C); (a) An ion-conducting polymer compound comprising a polymer substance in which at least one ionic compound is dissolved. A composite positive electrode (A); (b) negative electrode (B); and (c) composed of a molecular substance having a polyether structure and at least ionic conductivity, and an electrochemically active substance; An electrolyte (C) which is an ion-conductive polymer compound composed of a polymer substance in which an ionic compound is dissolved, the polymer substance having a polyether structure and ion conductivity And a polymer substance constituting the composite positive electrode (A) and / or the electrolyte (C) is formed by irradiation with ionizing radiation. 2. The negative electrode (B) is an ion-conducting polymer compound comprising a polymer substance in which at least one ionic compound is dissolved, and the polymer substance has a polyether structure. The battery according to claim 1, which is a composite negative electrode (D) composed of at least ionic conductivity and an electrochemically active substance. 3. The battery according to claim 2, wherein the polymer substance forming the composite negative electrode (D) is formed by irradiation with ionizing radiation. 4. A polymeric substance constituting the composite positive electrode (A),
The polymer substance constituting the composite negative electrode (B) and the electrolyte (C) is the same or different kind of epoxy group-containing polymerizable monomer having epoxy groups subjected to cationic ring-opening polymerization. Battery described. 5. A polymer substance constituting the composite positive electrode (A),
The polymer material constituting the composite negative electrode (B) and the electrolyte (C) is a polymer of a polymerizable monomer having two or more epoxy groups of the same or different type and having a network structure. The battery according to 1 or 2. 6. A polymeric substance constituting the composite positive electrode (A),
The polymer substances constituting the composite negative electrode (B) and the electrolyte (C) are the same or different types, and a polymerizable monomer having one epoxy group and a polymerizable monomer having two or more epoxy groups are polymerized. The battery according to claim 1, which is a polymer mixture and has a network structure. 7. The composite positive electrode (A) and / or the composite negative electrode (D) and / or the electrolyte (C) is at least 100 k.
The battery according to claim 1, which is formed by irradiating an electron beam having an acceleration voltage of V. 8. The battery according to claim 1, wherein the ion conductive polymer compound contains a substance capable of dissolving the ionic compound.