JPH07263000A - Battery and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a battery, which has high workability and improves long term reliability and safety, by forming a crack in the surface of a compound positive electrode, a compound negative electrode, which are formed of an electrochemical active material and an ion conductive high molecular compound, or an alkaline metal negative electrode and/or inside of an electrode. CONSTITUTION:A compound positive electrode 2 and a compound negative electrode 4 are coated by roll coating with an applicator roll or the like, doctor blade method, spin coating, and a means such as a bar coder, and thereafter, they are forcedly dried by far infrared heating, induction heating and hot air heating or the like. A crack such as hair crack, shallow crack and deep crack is thereby generated in the surface or the inside of the positive electrode 2 and the negative electrode 4. Intruding speed of the ion conductive high molecular compound composition liquid into the positive electrode 2 and the negative electrode 4 is therefor speeded up to simplify the manufacturing process, and soiling of the sealer 6 and collectors 1, 5 with the composition liquid is eliminated.

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 reversibly at ambient temperature, and relates to an electrolyte composed of an ion conductive polymer compound, an improved positive electrode and a negative electrode, and an improved production method thereof.

[0002]

2. Description of the Related Art Recently, as microelectronics has been used, as represented by a power source for memory backup of various electronic devices, a battery has been miniaturized in accordance with the storage of the battery in the electronic device and the integration with electronic elements and circuits. There is a demand for batteries that are lighter in weight, thinner, and have a higher energy density. Therefore, primary batteries and secondary batteries using non-aqueous electrolytes that can be made smaller and lighter have attracted attention as alternatives to conventional lead batteries and nickel-cadmium batteries. Many research institutes are still studying it due to the fact that nothing satisfying the practical physical properties such as the cycle characteristics has been found. In such a trend, the present inventors separately studied the following problems in designing a battery having a smaller size, a lighter weight, a higher energy density, and a higher reliability. There is. I) Electrode active material and electrode problem II) Electrolyte problem

The present invention has been found as a result of mainly considering the improvement on the above item I). The above problem I) is as follows. That is, the present inventor examined a battery called a thin battery (having a thickness per unit cell of 100 to 500 μm or a sheet battery). The outline of a typical manufacturing process of this type battery is as follows. That is, a mixture of an electrode active material, optionally a conductive agent, and an ion conductive polymer compound and optionally a binder is cast on a current collector, and then the ion conductive polymer is irradiated by irradiation with ionizing radiation. An electrode is cured (cured) by crosslinking a compound to form a composite electrode (for example, JP-A-5-226005 and JP-A-5-225).
90885). Then, the electrolyte layer is formed by casting the ion conductive polymer compound on the composite electrode / alkali metal electrode, curing and crosslinking. Examples of the method of forming the ion-conductive polymer compound include a method of casting a solution of the ion-conductive polymer compound and evaporating and removing the solvent, or coating a polymerizable monomer or macromer on a substrate and heating. There is a method of polymerizing or a method of curing by irradiation of ionizing radiation. (For example, Japanese Patent Laid-Open No. 5-178
(There are many such as No. 948) FIG. 1 shows a cross-sectional view of a typical sheet-shaped primary battery. In the figure, 1 is a positive electrode current collector made of stainless steel, which also serves as an exterior. 2 is a composite positive electrode,
Reference numeral 3 is an electrolyte layer made of an ion-conductive polymer compound. Reference numeral 4 is metallic lithium, and 5 is a negative electrode current collector plate made of stainless steel, which also serves as an exterior. No. 6 is a sealing agent made of modified polypropylene. The composite positive electrode 2 is composed of a positive electrode active material, a conductive agent, an ion conductive polymer compound and a binder, and the electrolyte layer 3 is composed of an ion conductive polymer compound.

In the sheet-shaped composite positive electrode 2 thus formed, the above-mentioned ion conductive polymer compound is crosslinked after the electrode curing, so that the ion conductive polymer compound composition liquid is applied onto the composite positive electrode 2. There was a situation in which, when applied, the impregnation speed of the above-mentioned composition liquid into the composite positive electrode 2 became slow. Therefore, the following problems have occurred. That is, 1) Since the impregnating property of the above composition liquid was poor, it took time to impregnate. 2) After the above-mentioned composition liquid was applied, the composition liquid adhered on the sealing agent 6, so that the sealing property after heat sealing was deteriorated. 3) After coating the above-mentioned composition liquid, the composition liquid had a problem of contamination of the sealing agent 6 and the current collectors 1 and 5. 4) Since the impregnating property of the above composition liquid is poor, the impedance of the electrode / electrolyte layer becomes high, which causes a problem in battery characteristics, particularly in battery characteristics after long-term storage. And so on.

On the other hand, the problem of the above II) is as follows. That is, as an electrolyte for a battery or an electrochemical device other than a battery that has conventionally used an electrochemical reaction, that is, an electric double layer capacitor, an electrochromic element, etc., a ionic compound is generally dissolved in a liquid electrolyte, particularly an organic electrolyte. Although liquid electrolytes have been used, liquid electrolytes are prone to liquid leakage to the outside of parts, elution of electrode substances, volatilization, etc., so problems such as long-term reliability and scattering of electrolytes in the sealing process, etc. Was a problem. Therefore, in order to improve these leakage resistance and long-term storage stability,
Ion-conductive polymer compounds having high ion-conductivity have been reported, and further research is being conducted as one of means for solving the above problems. The ion-conducting polymer compounds currently being researched are homopolymers or copolymers of ethylene oxide as a basic unit, such as linear polymers, reticulated crosslinked polymers or comb-shaped polymers. Ion-conductive polymer compounds using molecules are useful because they have high mechanical strength and good ionic conductivity at low temperatures, but an ion-conductive polymer compound layer is formed on the composite electrode. Even in the case of making it possible, the problems 1) to 4) described above cannot be avoided.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a battery using an ion-conductive polymer compound, which has extremely high workability, has no fear of liquid leakage to the outside, and has long-term reliability and safety. And a small and lightweight battery having high performance and high energy density.

[0007]

In order to achieve the above object, the present invention provides a polymer substance in which at least one ionic compound is dissolved and an organic compound in which the ionic compound is optionally dissolved. A configured ion-conductive polymer compound, which comprises the following (A), (B) or (B '), (C) a) at least an electrochemically active substance and the ion-conductive polymer compound A composite positive electrode (A) composed of an electron-conductive substance and optionally a binder made of an organic compound; (b) at least an electrochemically active substance, the ion-conductive polymer compound, and optionally an electron-conductive substance. A composite negative electrode (B) or an alkali metal negative electrode (B ') composed of a substance and optionally a binder made of an organic compound; c) an electrolyte (C) composed of at least one of the ion conductive polymer compounds. Consisting of In the above (A), it is an first invention in that it has a (B) surfaces and / or cracking within the electrode.

As a method for producing cracks on the surface of (A), (B) and / or the inside of the electrode, the method of (A),
A second invention is to generate the cracks by providing a forced drying step after applying the step (B), and mixing the electrochemically active substance and the ion conductive polymer compound. By providing the composite electrode, the above-mentioned object is achieved.

As a result of various studies on a method of producing cracks on the surface of the composite positive electrode (A) and the composite negative electrode (B) and / or inside the electrode, forced drying after the coating step of the (A) and (B). A method of providing steps is useful. As the above-mentioned application step, it is desirable to apply a uniform thickness using a roll coating such as an applicator roll, a doctor blade method, spin coating, a bar coder, etc., but not limited to these. In addition,
Using these means it is possible to increase the real surface area of the electrochemically active material in contact with the electrolyte layer and the current collector. It can be arranged in any thickness and in any shape. Examples of the forced drying step that can be performed in a particularly short time include, but are not limited to, far infrared heating, induction heating, and hot air heating. Forcibly drying by these methods can cause cracks on the surface of the composite electrode and / or inside the electrode. The cracks include the following. (a) Hair cracking → A minute crack that occurs on the surface of the uppermost coating film. (b) Checking → Cracks formed on the electrode surface, such as crow's foot shallow cracks, linear shallow cracks, and irregular shallow cracks. (c) Crazing → Similar to shallow cracking, but deeper and wider. (d) deep cracking → cracking through at least one layer of coating film.

The sheet-like composite positive electrode 2 thus constructed has cracks on its surface and / or inside the electrode. Therefore, when the ion conductive polymer compound liquid is applied onto the composite positive electrode 2. In addition, the impregnation speed of the above composition liquid into the composite positive electrode 2 is increased, and the following merits are produced. 1) Since the impregnating property of the composition liquid is improved, the manufacturing process is simplified. 2) Since the same composition liquid does not adhere to the sealing agent 6 after applying the above composition liquid, it is possible to prevent deterioration of the sealing property. 3) The composition liquid does not stain the sealing agent 6 and the current collectors 1 and 5 after the composition liquid is applied. 4) Since the electrode / electrolyte interface impedance is reduced as compared with the prior art, the diffusibility of Li ions at the time of discharging / charging can be improved, so that the battery characteristics are improved.

Further, the above ion-conductive polymer compound is
An ion-conducting polymer compound composed of a polymer compound in which at least one ionic compound is dissolved, for example, the ion-conducting polymer compound is
Those formed by. That is: at least an organic compound represented by the following chemical formula 1 and / or an organic compound represented by the following chemical formula 2 and / or the following chemical formula 3

[0012]

[Chemical 1]

(R ₁ , R ₂ and R ₃ are hydrogen atoms or lower alkyl groups having 1 or more carbon atoms, and m and n are m ≧ 1 and n ≧
An integer of 0 and an integer in the range of n / m = 0 to 5 are shown. )

[0014]

[Chemical 2]

(R ₄ , R ₅ and R ₆ are hydrogen atoms or lower alkyl groups having 1 or more carbon atoms, k and l are k ≧ 3 and l ≧
An integer of 0 and an integer in the range of k / l = 0 to 5 are shown. )

[0016]

[Chemical 3]

(R ₇ and R ₈ are hydrogen atoms or carbon atoms 1
The above lower alkyl groups, i ₁ , j ₁ , i ₂ , j ₂ ,
i ₃ and j ₃ are i ₁ ≧ 3, i ₂ ≧ 3, and i ₃ ≧, respectively.
3, j ₁ ≧ 0, j ₂ ≧ 0, j ₃ ≧ 0, j ₁ / i ₁ = 0
5 range number, j ₂ / i ₂ = 0 to 5 range number, j ₃ /
i ₃ is a number in the range of 0 to 5, and i ₁ + j ₁ ≧ 3
0, i ₂ + j ₂ ≧ 30, i ₃ + j ₃ ≧ 30. ): Ionic compound: Organic compound capable of dissolving ionic compound Arbitrary: High molecular weight ethylene oxide polymer and / or high molecular weight ethylene oxide-propylene oxide random copolymer A mixture of these is polymerized by irradiation with ionizing radiation. By reacting to form a crosslinked network structure, the ion conductive polymer compound can be obtained.

The above-mentioned ionic compounds soluble in the above-mentioned polymer compounds include, for example, LiClO ₄ , LiBF ₄ , and LiAs.
F ₆ , LiPF ₆ , LiI, LiBr, Li ₂ B ₁₀ Cl ₁₀ , LiCF ₃ SO ₃ , LiCF
₃ CO ₂ , LiSCN, NaI, NaSCN, NaBr, NaClO ₄ , KClO ₄ ,
Inorganic ionic salt containing one of Li, Na, or K such as KSCN, (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ). ₄ N
I, (C ₃ H ₇ ) ₄ NBr, (nC ₄ H ₉ ) ₄ NClO ₄ , (nC ₄ H ₉ ) ₄ NI, (C ₂ H
₅ ) ₄ N-maleate, (C ₂ H ₅ ) ₄ N-benzoate, (C ₂ H ₅ ) ₄ N-phtalat
Examples thereof include quaternary ammonium salts such as e and other organic ionic salts. Two or more kinds of these ionic compounds may be used in combination.

Next, in the present invention, the ion conductive polymer compound may contain an organic compound capable of dissolving the ionic compound contained in the ion conductive polymer compound,
By including this kind of substance, the ionic conductivity can be remarkably improved without changing the basic skeleton of the polymer compound. Above: Cyclic carbonic acid esters such as propylene carbonate and ethylene carbonate; cyclic esters such as γ-butyrolactone; tetrahydrofuran or its derivatives, 1,3-dioxane, 1,2-dimethoxyethane. ,
Ethers such as methyl diglyme; acetonitrile,
Examples thereof include nitriles such as benzonitrile; dioxolane or a derivative thereof; sulfolane or a derivative thereof alone or a mixture of two or more thereof. However, it is not limited to these. Moreover, the compounding ratio and the compounding method are arbitrary.

The mixing ratio of such an ionic compound is
The ionic compound is in a ratio of 0.0001 to 5.0 mol / liter, and more preferably 0.005 to 2.0 mol / liter with respect to the organic compounds of Chemical formula 1, Chemical formula 2, and Chemical formula 3 above. Is preferred. If the amount of the ionic compound used is too large, an excess ionic compound, for example, an inorganic ionic salt, does not dissociate, but merely mixes, resulting in a decrease in ionic conductivity. In addition, the compounding ratio of the ionic compound varies depending on the electrode active material. For example, in a battery using intercalation of a layered compound, it is preferable that the ionic conductivity of the electrolyte is around the maximum, and in a battery using a conductive polymer that utilizes a doping phenomenon as an electrode active material. It is necessary that the ion concentration in the electrolyte can be changed by charging and discharging.

Further, when the composite positive electrode and the composite negative electrode are manufactured, several kinds of dispersants and dispersion media are used in order to obtain a uniform mixed dispersion type coating liquid, or various characteristics of the composite positive electrode and the composite negative electrode (charge / discharge). Also, a binder for improving the cycle characteristics) can be added. Further thickener,
It is also possible to add a bulking agent, an adhesion aid, and the like. When a binder composed of an organic compound dissolved and / or dispersed in a solvent is used, an electrode active material, the above ion-conductive polymer compound or the like is dispersed in a binder solution prepared by dissolving the organic compound in the solvent. Or a method in which an electrode active material, the ion-conductive polymer compound, or the like is dispersed in a dispersion liquid of the organic compound and a dispersant for dispersing the organic compound. Etc. are general, but not limited to these.

Examples of the above organic compounds include the following. That is, acrylonitrile, methacrylonitrile, vinylidene fluoride, vinyl fluoride,
Examples thereof include polymers such as chloroprene, vinyl pyridine and its derivatives, vinylidene chloride, ethylene, propylene, cyclic dienes (eg, cyclopentadiene, 1,3-cyclohexadiene) and copolymers of the above organic compounds. It is not limited to.

Regarding the method of arranging the ion conductive polymer compound of the present invention on the surface of the composite positive electrode and the surface of the composite negative electrode, for example, roll coating such as an applicator roll, doctor blade method, screen coating, spin coating. It is desirable to apply a uniform thickness using a means such as a bar coder, but it is not limited thereto. By using these means, it is possible to arrange them on the surface of the composite positive electrode and the surface of the composite negative electrode in any thickness and in any shape.

Further, as the positive electrode active material used in the composite positive electrode of the present invention, the following battery electrode materials can be mentioned. That is, group I metal compounds such as CuO, Cu ₂ O, Ag ₂ O, CuS and CuSO ₄ , group IV metal compounds such as TiS ₂ , SiO ₂ and SnO, V
_{2 O 5, V 6 O 12} , VO X, Nb 2 O 5, Bi 2 O 3, V metal compounds such as _{Sb 2 O 3, Cr0 3,} Cr 2 O 3, MoS 2, WO 3, SeO 2 , etc. VI
Group VII metal compounds such as MnO ₂ and Mn ₂ O ₃
Group VIII metal compounds such as Fe ₂ O ₃ , FeO, Fe ₃ O ₄ , Ni ₂ O ₃ , NiO, CoS ₂ , and CoO, or general formulas Li _X MX ₂ , Li _X
MN _Y X ₂ (M and N are metals of groups I to VIII, X is a chalcogen compound such as oxygen and sulfur), and the like.
For example, a metal compound such as a lithium-cobalt-based composite oxide or a lithium-manganese-based composite oxide, a conductive polymer compound such as polypyrrole, polyaniline, polyparaphenylene, polyacetylene, or a polyacene-based material, a pseudo-graphite structure carbonaceous material Materials and the like, but are not limited to these.

Further, examples of the negative electrode active material used for the composite negative electrode or the alkali metal negative electrode include the following battery electrode materials. That is, as a carbonaceous material such as carbon [for example, the above carbonaceous material is analyzed by X-ray diffraction or the like;

[0026]

[Table 1]

Further, carbon powder (average particle diameter of 15 μm or less) or carbon fiber obtained by firing an anisotropic pitch at a temperature of 2000 ° C. or higher is preferable, but it is not limited to these ranges. . ] Or lithium metal, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-
Gallium and lithium metal-containing alloys such as wood alloys, but are not limited thereto. These negative electrode active materials can be used alone or in combination of two or more.

In these cases, carbon such as graphite, carbon black, acetylene black, etc. (wherein the carbon here has completely different characteristics from the carbon in the above-mentioned negative electrode active material). ) And a conductive material such as a metal powder or a conductive metal oxide can be mixed in the composite positive electrode and the composite negative electrode to improve electron conduction.

The positive electrode current collector plate is preferably made of a material such as aluminum, stainless steel, titanium or copper, and the negative electrode current collector plate is preferably made of a material such as stainless steel, iron, nickel or copper, but is not particularly limited thereto. Absent.

[0030]

EXAMPLES The details of the present invention are described below with reference to examples, but the present invention is not limited thereto. (Example 1) The sheet-shaped battery of Example 1 has the following a)
To d) are formed. a) The composite positive electrode 2 is formed as follows. That is, manganese dioxide which is a positive electrode active material, acetylene black which is a conductive agent are mixed in a weight ratio of 85:15, and ethylene-propylene-1,3- which is a binder.
Xylene solution of cyclohexadiene copolymer (2 wt%
The mixture of the solutions) was mixed with dry inert gas (dew point -6
Inert gas below 0 ° C. Hereinafter, it is abbreviated as an inert gas. ) Were mixed in an atmosphere at a weight ratio of 2.2: 2 (mixture A ₁ ). Organic compound _{1 in} which this mixture A ₁ and the organic compound represented by the following Chemical formula 4, Chemical formula 5, and Chemical formula 6 are mixed at 3: 5: 2
A mixture A ₂ was obtained by mixing 0 part by weight, 1 part by weight of lithium perchlorate and 20 parts by weight of propylene carbonate in an inert gas atmosphere at a weight ratio of 20: 3.

[0031]

[Chemical 4]

[0032]

[Chemical 5]

[0033]

[Chemical 6]

B) On a current collector having an electron conductive layer made of graphite and a polyamide-imide resin formed on the surface of stainless steel, the above mixture A ₂ was applied on the current collector having the above electron conductive layer. Cast by screen coating.
Then, by using a far-infrared ray drying furnace, drying was carried out at 60 ° C. for 5 minutes in an inert gas atmosphere to generate cracks on the surface and inside of the composite positive electrode. Then, in an inert gas atmosphere, acceleration voltage 250 kV, electron dose 8 Mrad
The composite positive electrode was formed by irradiating the electron beam of. The thickness of the composite positive electrode coating formed on the positive electrode current collector is 1
It was 20 μm.

C) The electrolyte layer 3 is formed as follows. That is, the organic compound 30 obtained by mixing the organic compounds of Chemical formula 4, Chemical formula 5, and Chemical formula 6 of step a) in a weight ratio of 4: 4: 2.
A mixture of 6 parts by weight of lithium perchlorate and 64 parts by weight of propylene carbonate is used as the composite positive electrode 2
The film was cast by screen coating on top, and the acceleration voltage was 250 kV and the electron dose was 8 Mra in an inert gas atmosphere.
The electron beam of d was irradiated and cured. The thickness of the electrolyte layer thus obtained was 25 μm.

D) Lithium metal was used as the negative electrode active material of the battery, and this was pressed onto a negative electrode current collector plate made of stainless steel.

E) The lithium / negative electrode current collector obtained in step d) was brought into contact with the positive electrode current collector / composite positive electrode / electrolyte obtained in step c). This produced the sheet-shaped battery of Example 1.

(Comparative Example 1) In the same manner as in Example 1 except that the far infrared ray drying step was not provided in the step b).

FIG. 1 is a sectional view of the sheet-like battery of the present invention. In the figure, 1 is a positive electrode current collector made of stainless steel,
It also serves as the exterior. An electron conductive layer made of graphite and polyamide-imide resin is provided on the surface of the composite positive electrode side. Reference numeral 2 denotes a composite positive electrode, in which manganese dioxide was used as a positive electrode active material, acetylene black was used as a conductive agent, and ethylene-propylene-1,3-cyclohexadiene copolymer was used as a binder. Further, 3 is an electrolyte layer made of the ion conductive polymer compound of the present invention. 4 is metallic lithium,
Reference numeral 5 is a negative electrode current collector plate made of stainless steel, which also serves as an exterior. No. 6 is a sealing agent made of modified polypropylene.

The electrode area of the sheet-shaped batteries of Example 1 and Comparative Example 1 can be variously changed by the manufacturing process. In Example 1 and Comparative Example 1, the electrode area is 50 cm ^2. Was produced. The initial discharge characteristics of these sheet batteries when discharged at 25 ° C and a load of 3 kΩ and the discharge characteristics after storage at 60 ° C for 100 days were examined. Figure 2
Is the discharge characteristics (initial discharge characteristics) immediately after cell production and 60
It shows the discharge characteristics after storage at ℃ for 100 days. As is clear from FIG. 2, the sheet-shaped battery of Example 1 of the present invention is superior to the sheet-shaped battery of Comparative Example 1 in initial discharge characteristics and discharge characteristics after storage at 60 ° C. for 100 days. Is recognized.

Further, in the battery of Comparative Example 1, since the above-mentioned ion conductive compound composition liquid adhered to the sealing agent 6, cells with defective sealing were generated as shown in Table 2. However, in the battery of Example 1, No bad sealing was seen. At the same time, Table 2 also shows stains on the current collector that also serves as an exterior.

[0042]

[Table 2]

(Example 2) The sheet-shaped battery of Example 2 is formed through the following steps a) to i). a) The composite positive electrode is formed as follows. That is, LiCoO 2 as a positive electrode active material in an inert gas atmosphere.
_{1. A} mixture of ₂ and acetylene black as a conductive agent in a weight ratio of 85:15 and a mixture of a dimethylformamide solution of polyacrylonitrile (2 wt% solution) as a binder in an inert gas atmosphere. They were mixed in a weight ratio of 4: 2 (mixture B ₁ ). This mixture B
₁ and the organic compound of the above Chemical formula 4, Chemical formula 5, and Chemical formula 6: 3: 5: 2
10 parts by weight of the organic compound mixed with 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 in an inert gas atmosphere at 17: Mixture B ₂ was obtained by mixing in a weight ratio of 3.

B) On the current collector having the electron conductive layer made of graphite and polyamide-imide resin formed on the surface of aluminum, the above mixture B ₂ is applied to the current collector having the electron conductive layer. Cast by screen coating. Then, by using a far-infrared ray drying furnace, the dimethylformamide was removed by performing drying at 70 ° C. for 2 minutes in an inert gas atmosphere, and cracks were generated on the surface and inside of the composite positive electrode. Then, the composite positive electrode was formed by irradiating an electron beam with an acceleration voltage of 250 kV and an electron dose of 12 Mrad in an inert gas atmosphere. The thickness of the composite positive electrode coating film formed on the positive electrode current collector was 120 μm.

C) Next, in order to form an ion conductive polymer compound on the composite positive electrode, the above chemical formula 4, chemical formula 5, chemical formula 6
30 parts by weight of an organic compound obtained by mixing the organic compound of 4) in a weight ratio of 4: 4: 2, and 6 parts by weight of lithium tetrafluoroborate,
A mixture of 32 parts by weight of 1,2-dimethoxyethane and 32 parts by weight of γ-butyrolactone was cast on the above composite positive electrode by screen coating in an inert gas atmosphere, and then an accelerating voltage of 2 in an inert gas atmosphere.
The ion conductive polymer compound layer was cured by irradiating with an electron beam of 50 kV and an electron dose of 8 Mrad.
The thickness of the electrolyte layer thus obtained was 25 μm.

D) The composite negative electrode is formed as follows. That is, in an inert gas atmosphere, a toluene solution of a carbon powder as a negative electrode active material and a copolymer of ethylene-propylene-cyclopentadiene as a binder (2
wt% solution) was mixed in an inert gas atmosphere at a weight ratio of 2: 5 (mixture C ₁ ). This mixture C ₁ and 10 parts by weight of an organic compound prepared by mixing the organic compounds of the above Chemical formulas 4, 5 and 6 in a ratio of 3: 5: 2, 1 part by weight of lithium tetrafluoroborate and 1,2-dimethoxyethane 10 A mixture C ₂ was obtained by mixing 1 part by weight and a mixture of 10 parts by weight of γ-butyrolactone at a weight ratio of 18: 2 in a dry inert gas atmosphere.

E) These mixtures C ₂ were cast by screen coating on a negative electrode current collector made of copper foil. Then, using a far infrared drying furnace, xylene was removed by performing drying at 65 ° C. for 3 minutes in an inert gas atmosphere, and cracks were generated on the surface and inside of the composite positive electrode. Then, in an inert gas atmosphere, accelerating voltage 250
The composite negative electrode was formed by irradiating with an electron beam of kV and an electron dose of 12 Mrad. The composite negative electrode formed on the negative electrode current collector had a thickness of 80 μm.

F) The electrolyte layer is formed as follows. That is, 30 parts by weight of an organic compound prepared by mixing the organic compounds of the above chemical formulas 4, 5, and 6 in a weight ratio of 4: 4: 2, 6 parts by weight of lithium tetrafluoroborate, and 32 parts by weight of 1,2-dimethoxyethane. And 32 parts by weight of γ-butyrolactone are mixed and cast on the above composite negative electrode by screen coating in an inert gas atmosphere, and then an accelerating voltage of 250 kV and an electron beam with an electron dose of 8 Mrad are applied in the inert gas atmosphere. Irradiation was performed to cure the ion conductive polymer compound layer. The thickness of the electrolyte layer thus obtained was 25 μm.

G) The electrolyte layer / composite negative electrode / negative electrode current collector obtained in step f) was brought into contact with the positive electrode current collector / composite positive electrode / electrolyte layer obtained in step c). Thereby, the sheet-shaped battery of Example 2 of the present invention was manufactured.

(Comparative Example 2) In steps b) and e) of Example 2, a far infrared ray drying step was not provided,
It was made by the same method.

The electrode area of the sheet-shaped batteries of Example 2 and Comparative Example 2 can be variously changed by the manufacturing process. In Example 2 and Comparative Example 2, the electrode area is 50 cm. ² was produced. Using these sheet-shaped batteries, a charge / discharge cycle test of 100 μA / cm ² constant current / constant voltage charge and 100 μA / cm ² constant current discharge at 25 ° C. was performed. The end-of-charge voltage 4.1
A charging / discharging cycle test was conducted with V and discharge end voltage of 2.7V. FIG. 3 shows the relationship between the number of charge / discharge cycles and the battery capacity, the charge / discharge characteristics immediately after cell preparation and the charge / discharge characteristics after storage at 60 ° C. for 100 days. As can be seen from FIG. 3, the sheet-shaped battery of the present invention exhibits excellent charge / discharge cycle characteristics as compared with the sheet-shaped battery of the comparative example.

Further, in the battery of Comparative Example 2, the above-mentioned ion conductive compound composition liquid adhered to the sealing agent 6, so that cells with defective sealing were generated as shown in Table 3. However, in the battery of Example 2, No bad sealing was seen. At the same time, Table 3 also shows stains on the current collector that also serves as an exterior.

[0053]

[Table 3]

Although not explicitly shown in this embodiment,
Similar effects are obtained when other drying methods are used. In short, the problem is how to produce the intended crack, and when the means are different, the above crack can be produced by controlling the conditions. Furthermore, thin electrodes can be produced by various methods such as pressing, sputtering, suspension, and coating, and it becomes possible to increase the actual surface area of the active substance that is in contact with the electrolyte layer and the current collector.

Although the above examples and various other statements relate primarily to the use of lithium, the use of other alkali metals such as sodium is also within the scope of the invention.

[0056]

EFFECTS OF THE INVENTION As is apparent from the above description, since the sheet-shaped composite electrode has cracks on the surface and / or inside the electrode, the composite electrode 2 is coated with the ion conductive polymer compound liquid. In doing so, the impregnation rate of the above composition liquid into the composite positive electrode 2 becomes faster. Therefore, the following effects are exhibited. 1) Since the impregnating property of the composition liquid is improved, the manufacturing process is simplified. 2) Since the same composition liquid does not adhere to the sealing agent 6 after applying the above composition liquid, it is possible to prevent deterioration of the sealing property. 3) The composition liquid does not stain the sealing agent 6 and the current collectors 1 and 5 after the composition liquid is applied. 4) Since the electrode / electrolyte interface impedance is reduced as compared with the prior art, the diffusibility of Li ions at the time of discharging / charging can be improved, so that the battery characteristics are improved. From these, the workability of the battery manufacturing process and the performance of the battery can be improved.

[Brief description of drawings]

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

FIG. 2 shows the discharge characteristics (initial discharge characteristics) of the sheet-shaped battery of Example 1 and the sheet-shaped battery of Comparative Example 1 immediately after cell production and
6 is a graph showing discharge characteristics after storage at 60 ° C. for 100 days.

FIG. 3 is a graph showing the relationship between the number of charge / discharge cycles and the battery capacity of the sheet-shaped battery of Example 2 and the sheet-shaped battery of Comparative Example 2. (Charge / discharge characteristics immediately after cell fabrication and 60 ℃, 100
The charge / discharge characteristics after storage for a day are shown. )

[Explanation of symbols]

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

Claims (2)

[Claims] 1. A battery comprising a composite positive electrode, an electrolyte and a composite negative electrode or an alkali metal negative electrode, wherein the electrolyte is a polymeric substance in which at least one ionic compound is dissolved and optionally an ionic compound. Which is composed of an ion-conducting polymer compound composed of an organic compound capable of dissolving the above, a composite positive electrode, a composite negative electrode or an alkali metal negative electrode, and an electrolyte (A), (B) or (B ′)
A battery comprising (C), characterized by having cracks on the surfaces (A) and (B) below and / or inside the electrode. A) A composite positive electrode (A) composed of at least an electrochemically active substance and a binder composed of the ion-conductive polymer compound; and b) At least an electrochemically active substance and the ion-conductive polymer compound. A composite negative electrode (B) or an alkali metal negative electrode (B ′) composed of a binder consisting of: (c) an electrolyte (C) comprising at least one of the ion-conductive polymer compounds; 2. A method for producing cracks on the surface of (A), (B) and / or inside of the electrode, comprising:
The method for producing a battery according to claim 1, wherein the cracking is caused by providing a forced drying step after the coating step of (B).