JP3055596B2 - Battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery which operates reversibly at ambient temperature, and more particularly to an improvement in an electrolyte, a positive electrode and a negative electrode.

[0002]

2. Description of the Related Art Recently, as represented by a power supply for memory backup of various electronic devices, the recent trend toward microelectronics has led to the miniaturization of batteries along with the integration of batteries in electronic devices and the integration of electronic elements and circuits. There is a demand for a battery that is lighter and thinner and has a higher energy density. Therefore, primary batteries and secondary batteries using non-aqueous electrolytes that can be reduced in size and weight have been attracting attention as batteries replacing conventional lead batteries and nickel-cadmium batteries. Currently, many research institutions are examining the lack of a material that satisfies practical physical properties such as self-discharge characteristics.

[0003] In such a flow, the present inventors,
In designing a battery that is smaller, lighter, has a higher energy density, and has higher reliability, the following problems are separately studied. 1) Problems with the electrode active material and the electrodes 2) Problems with the electrolyte The present invention has been found as a result of mainly considering the improvement in the above 2).

[0004] The above problem 2) is as follows. That is, conventionally, as an electrolyte for a battery or an electrochemical device other than a battery utilizing an electrochemical reaction, that is, an electric double layer capacitor or an electrochromic element, an ionic compound is generally dissolved in a liquid electrolyte, particularly an organic electrolyte. However, since liquid electrolytes are liable to leak out of components, elute and volatilize electrode materials, problems such as long-term reliability and splashing of electrolyte during the sealing process Was a problem.

[0005] Therefore, in order to improve the liquid leakage resistance and the long-term storage property, an ion-conductive polymer compound having high ion conductivity has been reported, and further research has been conducted as one of means for solving the above problems. Is underway.

The ion conductive polymer compounds currently being studied are homopolymer or copolymer linear polymers, network crosslinked polymers or comb polymers having ethylene oxide as a basic unit. For the purpose of increasing the ionic conductivity of the polymer, it has been proposed and implemented to use a crosslinked polymer or a comb polymer to prevent crystallization. In particular, an ion conductive polymer compound using the above network crosslinked polymer is useful because it has high mechanical strength and good ionic conductivity at low temperatures. Electrochemical cells using the above-mentioned ion-conductive polymer compounds are widely described in patent documents and the like. For example, US Pat. No. 4,303,748 (1981) by Armand et al.
No. 4,589,197 to North (1986) and US Pat. No. 4,547,440 to Hooper et al. (198).
5) and so on. One of the features of these cells is that an ion-conductive polymer compound obtained by dissolving an ionic compound in a polymer material having a polyether structure is used.

However, in order to use the above-mentioned ion-conductive polymer compound as an electrolyte for batteries utilizing electrochemical reactions and electrochemical devices other than batteries, high ionic conductivity and good mechanical properties (mechanical strength) are required. And flexibility), but these two properties are contradictory. That is, at present, most of the above-mentioned patent documents are operated mainly at elevated temperatures because the ionic conductivity at room temperature or lower is below the practical range.

Therefore, as a simple method for improving the ionic conductivity, for example, Japanese Patent Application Laid-Open Nos.
A method has been proposed in which an organic solvent (particularly preferably a high dielectric constant organic solvent) is added to an ion-conductive polymer compound to maintain a solid state, as represented by 5779 and US Pat. No. 4,792,504. However, as a result, the ionic conductivity is definitely improved, but the film strength is significantly reduced.

When the above-mentioned ion-conductive polymer compound is applied as an electrolyte for an electrochemical device, it is necessary to reduce the thickness of the electrolyte in order to reduce the internal resistance. Particularly for the present inventors, a thin battery (or a sheet-shaped battery) that is a battery that is smaller and lighter and has a higher energy density.
It can be said that the above-mentioned thinning is just the most important proposition in designing a battery called a battery. In the case of the above-mentioned ion-conductive polymer compound, a uniform thin film can be easily processed into an arbitrary shape, but this method poses a problem.

Accordingly, the present inventors have proposed a method of applying a polymerizable monomer or macromer containing an inorganic compound whose surface has been hydrophobized to a substrate and performing heat polymerization, as described in JP-A-4-245170. Alternatively, a method of curing by irradiation with actinic rays has been proposed. However, even in the case of using the above method, when the ion-conductive polymer compound thin film is actually laminated between the electrodes and a battery or an electrochromic device is assembled, the electrolyte layer is damaged by compression deformation, There was a case where a slight short circuit occurred. Therefore, in order to make the ion conductive polymer compound layer thinner uniformly, improvement of its mechanical properties is important together with ion conductivity.

On the other hand, when an abnormal current flows due to an external short-circuit or incorrect connection of the battery, the internal temperature of the battery rises remarkably, and in the worst case, a serious accident such as ignition or rupture may occur. .

In order to avoid such a danger, it has been proposed to use a polyethylene porous film or a polypropylene porous film as a separator in a lithium battery (JP-A-60-23954, JP-A-2-23). No. 75151). The reasons for using these porous separators are: a) Usually located between the positive electrode and the negative electrode to prevent a short circuit between both electrodes. b) When the internal temperature of the battery rises due to an abnormal current, the battery is melted at a predetermined temperature, its electric resistance is increased, the current is cut off, and excessive temperature rise is prevented to ensure safety.

In the case where the temperature rises abnormally as in b), the function of interrupting the current by increasing the electric resistance and preventing the ignition and explosion to ensure the safety of the battery is generally called a shutdown characteristic. This is an essential characteristic for battery separators. It is important for the lithium battery separator to have this shutdown characteristic. However, it is important that the electric resistance is started at an appropriate temperature (hereinafter, this temperature is referred to as a shutdown start temperature) and that the increased electric resistance is appropriate. It is also required to maintain the temperature up to a certain temperature. If the shutdown start temperature is too low, the electric resistance starts to increase due to a slight rise in the temperature inside the battery, resulting in poor practicability. If the shutdown start temperature is too high, the safety is insufficient.

However, it has been difficult to provide the above-mentioned ion-conductive polymer compound with the above-mentioned shutdown characteristics. The reasons are as follows: c) In order to improve the ionic conductivity and mechanical properties, the polymer is mainly composed of a crosslinked polymer of polyether, and the shutdown property does not appear at an appropriate temperature. In addition, even when the shutdown characteristic appears, it is not possible to cope with the above-mentioned abnormal temperature rise because the effect is small or the reaction at the time of appearance is slow. d) Since the cross-linked polymer of polyether and Li ions are in an associated state, it is difficult to give the polymer itself shutdown properties. And so on.

[0015]

SUMMARY OF THE INVENTION The present invention provides a battery using an ion-conductive polymer compound, which is extremely small and light in the following points as compared with a conventional battery. That is: 1) Long-term reliability without any fear of liquid leakage to the outside. 2) Extremely high safety even when abnormal current occurs. 3) High performance, high energy density and very high workability. It is.

[0016]

In order to achieve the above object, the present invention provides a battery comprising a composite positive electrode, an electrolyte, and a composite negative electrode or a negative electrode mainly composed of an alkali metal, wherein the electrolyte comprises: The composite positive electrode and the composite negative electrode both contain the ion-conductive polymer compound as a constituent material, the ion-conductive polymer compound containing at least one ionic compound in a dissolved state. wherein the conductive polymer compound, the following, and,
It is a first aspect of the present invention to further include or .

At least an organic compound represented by the following chemical formula 1 or / and / or the following chemical formula 2 or / and the following chemical formula 3

[0018]

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(R ₁ , R ₂ and R ₃ are hydrogen or a lower alkyl group having 1 or more carbon atoms, m and n are m ≧ 1, n ≧ 0,
Indicate a number in the range of n / m = 0 to 5. )

[0020]

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(R ₄ , R ₅ and R ₆ are hydrogen or a lower alkyl group having 1 or more carbon atoms, and s and t are s ≧ 3, t ≧ 0,
Indicates a number in the range of t / s = 0 to 5. )

[0022]

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(R ₇ and R ₈ are hydrogen or a lower alkyl group having 1 or more carbon atoms, p ₁ , p ₂ , p ₃ , q ₁ , q ₂ , q
₃ is p ₁ ≧ 3, p ₂ ≧ 3, p ₃ ≧ 3, q ₁ ≧
0, q ₂ ≧ 0, q ₃ ≧ 0, the number in the range of q ₁ / p ₁ = 0 to 5, the number in the range of q ₂ / p ₂ = 0 to 5, q ₃ / p ₃ = 0
A number in the range of 5 and p ₁ + q ₁ ≧ 10, p ₂ + q
₂ ≧ 10 and p ₃ + q ₃ ≧ 10. ): Ionic compound: Organic compound capable of dissolving ionic compound: Polyolefin powder: Inorganic compound whose surface is hydrophobized

Further, as a method of forming the composite positive electrode, the electrolyte and the composite negative electrode, the second invention is to form the electrode and the electrolyte by irradiating active rays such as ionizing radiation. The above object has been attained by providing an electrode by mixing a polymer with an ion-conductive polymer compound.

In the present invention, the electrolyte is as described above,
Because it is made of an ion conductive polymer compound, compared to conventional ion conductive polymer solid electrolytes,
The shutdown characteristics, the ionic conductivity, and the mechanical characteristics simultaneously satisfied the practicality.

That is, in the present invention, when the internal temperature of the battery rises due to an abnormal current, the polyolefin powder melts at a predetermined temperature and cuts off the current due to an increase in electric resistance, whereby a shutdown characteristic can be exhibited. Was.
Therefore, even in the case where the above-described problem occurs, it becomes possible to avoid ignition and rupture, thereby improving the safety of the battery. Further, generation of dendrite when lithium metal is used for the negative electrode is suppressed, and the liquid leakage resistance and, consequently, the long-term reliability are improved. In addition, since the mechanical strength of the electrolyte is also improved, it is possible to prevent a slight short circuit or the like at the time of manufacturing the cell and during the charge / discharge cycle, thereby improving the charge / discharge cycle characteristics and manufacturing a high-performance electrode.

[0027] Further, the above: The inorganic compound whose surface is hydrophobized minimizes the decrease in ionic conductivity and dramatically increases the mechanical strength as compared with the conventional ionic conductive polymer compound. It became possible. Therefore, by using the above-mentioned ion-conductive polymer compound as an electrolyte, it is possible to suppress the generation of dendrites of lithium, and to provide an electrolyte (separator) having excellent mechanical strength and being thermally and electrochemically stable. It is possible to do.

Incidentally, even when the composite negative electrode is used,
It is also possible to suppress the generation of dendrites of lithium in the peripheral portion of the composite negative electrode, and to provide an electrolyte layer having excellent mechanical strength and being thermally and electrochemically stable. These factors include: a) Because the polyolefin powder of the present invention is contained. b) To contain an inorganic compound of the present invention whose surface has been subjected to a hydrophobic treatment. c) Because the above-mentioned ion-conductive polymer compound is constituted by at least the organic compound represented by the above formulas (1) to (3). And the like.

The above-mentioned ionic compound soluble in the polymer compound thus obtained is, for example, LiCl
O ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiI, LiBr, Li ₂ B ₁₀ C
_{l 10, LiCF 3 SO 3,} LiCF 3 CO 2, LiSCN, NaI, NaSCN, NaB
r, an inorganic ion salt containing one kind of Li, Na, or K such as NaClO ₄ , KClO ₄ , KSCN, (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (C
_{2 H 5) 4 NClO 4,} (C 2 H 5) 4 NI, (C 3 H 7) 4 NBr, (nC 4 H 9) 4 NCl
O ₄ , (nC ₄ H ₉ ) ₄ NI, (C ₂ H ₅ ) ₄ N-maleate, (C ₂ H ₅ ) ₄ N-benzo
quaternary ammonium salts such as ate and (C ₂ H ₅ ) ₄ N-phtalate, and other organic ion salts. These ionic compounds may be used in combination of two or more.

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 such a substance, the ionic conductivity can be significantly improved without changing the basic skeleton of the polymer compound. Above: As organic compounds capable of dissolving the ionic compound, cyclic carbonates such as propylene carbonate and ethylene carbonate; cyclic esters such as γ-butyrolactone; tetrahydrofuran or derivatives thereof, 1,3-dioxane, 1,2-dimethoxyethane ,
Ethers such as methyldiglyme; acetonitrile,
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. The mixing ratio and the mixing method are arbitrary.

The mixing ratio of such an ionic compound is as follows:
The ratio of the ionic compound is 0.0001 to 5.0 mol / l, preferably 0.005 to 2.0 mol / l, with respect to the organic compounds of the above chemical formulas 1, 2 and 3. Is preferred. If the amount of the ionic compound is too large, an excessive amount of the ionic compound, for example, an inorganic ionic salt is not dissociated, but merely mixed, resulting in a reduction in ionic conductivity. Further, the appropriate mixing ratio of the ionic compound differs depending on the electrode active material. For example, in a battery using intercalation of a layered compound, the vicinity where the ionic conductivity of the electrolyte is maximized is preferable, and in a battery using a conductive polymer utilizing a doping phenomenon as an electrode active material. In addition, it is necessary that the ion concentration in the electrolyte can respond to changes due to charge and discharge.

The method of containing the ionic compound is not particularly limited. For example, after dissolving in an organic solvent such as the above-mentioned chemical formula 1 in an organic solvent such as methyl ethyl ketone and mixing uniformly, the pressure is reduced under vacuum to reduce the organic compound. Examples of the method include a method in which the ionic compound is contained in a compound, a method in which the ionic compound is dissolved in an organic compound capable of dissolving the ionic compound, and then, the compound is uniformly mixed with the organic compound as shown in Chemical formula 1.

Above: Polyolefin powders include polyethylene powders and polypropylene powders. In the present invention, polyethylene fine powders are considered to be particularly promising for the purpose of improving shutdown characteristics and mechanical properties. However, it is not limited to these.

Examples of the polyolefin powder include Miperon XM-220, a fine-particle / ultra-high-molecular-weight polyolefin powder manufactured by Mitsui Petrochemical Industries, Ltd., and flow beads manufactured by Sumitomo Seika Co., Ltd. By using these polyolefin powders, the ion-conductive polymer compound has the following characteristics.

I) Unlike a general polyolefin powder, the average particle diameter is 10 to 30 μm.
And excellent dispersibility when mixed with the ionic conductive polymer compound, so that the compound is uniformly dispersed in the ion-conductive polymer compound, so that shutdown characteristics are well exhibited. ii) The above polyolefin powder has a melting point of 109-1.
Since the temperature is 36 ° C., the shutdown characteristics are well exhibited. iii) Since the polyolefin powder is uniformly dispersed in the ion-conductive polymer compound as in i), there is no place where the mechanical properties are partially increased as in the related art.

Above: Examples of the inorganic compound whose surface is hydrophobized include an inorganic oxide whose surface is hydrophobized, which is obtained by a method developed by DEGUSSA.
In the above method, an inorganic oxide obtained by high-temperature hydrolysis of an inorganic chloride in an acid-chlorine flame is converted into an inert gas carrier of dimethyldichlorosilane and steam for about 4 hours.
It is produced in a fluidized bed reactor heated to 00 ° C.

The inorganic chlorides include, but are not limited to, silicon tetrachloride, aluminum chloride, and titanium chloride, and the inorganic oxides include silica, alumina, and titania. Therefore, as the inorganic compound whose surface is hydrophobized, silica,
A surface of alumina, zirconia, titania or the like treated with an alkyl group such as a methyl group or an octyl group can be used, but is not limited thereto. Two or more of these inorganic compounds whose surfaces have been hydrophobized with an alkyl group may be used in combination.

Further, since the surface of the inorganic compound is subjected to hydrophobic treatment and the average particle diameter of the primary particles is within 1 μm or less, for example, the inorganic compound is uniformly mixed in a polymerizable monomer. In order to show extremely excellent dispersibility and high thickening effect not found in other inorganic compounds,
Improvement in workability when producing the ion-conductive polymer compound thin film is realized. The surface-hydrophobicized inorganic compound can be dried at 100 to 300 ° C. under reduced pressure as necessary to remove water adsorbed on the surface.

When producing the above-mentioned composite positive electrode and composite negative electrode, several kinds of dispersants and dispersing media or various characteristics (charge / discharge) of the composite positive electrode and composite negative electrode are used in order to obtain a uniform mixed dispersion coating solution. And a binder for improving cycle characteristics). Further thickeners,
It is also possible to add a bulking agent, a tackifier, and the like.

When a binder comprising an organic compound dissolved and / or dispersed in a solvent is used, an electrode active material or the above-mentioned ion-conductive polymer compound is added to a binder solution in which the organic compound is dissolved in a solvent. A method of using the dispersed substance as a coating liquid, or a dispersion liquid of the organic compound and a dispersant for dispersing the organic compound, wherein the electrode active material or the ion-conductive polymer compound is dispersed. Is generally used, but the method is not limited thereto.

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

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

The following positive electrode active materials are used as the positive electrode active material for the composite positive electrode of the present invention. 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;
_{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 , CoO, or the general formula Li _X MX ₂ , Li _X
MN _Y X ₂ (M and N are metals of groups I to VIII, and X is a chalcogen compound such as oxygen or sulfur.)
For example, metal compounds such as lithium-cobalt-based composite oxides or lithium-manganese-based composite oxides, and conductive polymer compounds such as polypyrrole, polyaniline, polyparaphenylene, polyacetylene, and polyacene-based materials; The material is 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;

[0045]

[Table 1]

Further, carbon powder (an average particle diameter of 15 μm or less) or carbon fiber obtained by firing anisotropic pitch at a temperature of 2000 ° C. or more is desirable, but 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.

The method of disposing the composite positive electrode and the composite negative electrode of the present invention on the positive electrode current collector and the negative electrode current collector includes, for example, roll coating such as an applicator roll, doctor blade method, spin coating, and the like. It is desirable to apply a uniform thickness using a means such as a bar coder, but it is not limited thereto. When these means are used, it is possible to increase the actual surface area of the electrochemically active substance that comes into contact with the electrolyte layer and the current collector. It can be arranged in any thickness and any shape.

In these cases, if necessary, carbon such as graphite, carbon black, and acetylene black (carbon having a property completely different from that of the above-described carbon in the negative electrode active material). ) And a conductive material such as a metal powder and a conductive metal oxide can be mixed in the composite positive electrode and the composite negative electrode to improve electron conduction.

Materials such as aluminum, stainless steel, titanium, and copper are preferable for the positive electrode current collector plate, and materials such as stainless steel, iron, nickel, and copper are preferable for the negative electrode current collector plate. Absent.

[0050]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

(Example 1) FIG. 1 is a sectional view of a sheet-shaped battery according to Example 1 of the present invention. In the figure, reference numeral 1 denotes a positive electrode current collector made of aluminum, which also serves as an exterior. An electron conductive layer is provided on the surface on the composite positive electrode side. Reference numeral 2 denotes a composite positive electrode, in which LiCoO ₂ was used as a positive electrode active material, acetylene black was used as a conductive agent, and polyacrylonitrile was used as a binder. Reference numeral 3 denotes an electrolyte layer made of the ion-conductive polymer compound of the present invention. 4 is a composite negative electrode,
Carbon powder was used as the negative electrode active material, and ethylene-
A propylene-cyclopentadiene copolymer was used.
Reference numeral 5 denotes a negative electrode current collector made of rolled copper, which also serves as an exterior. Reference numeral 6 denotes a sealing agent made of modified polypropylene.

The sheet-shaped battery of Example 1 has the following a) to
It is formed through the step i). a) The composite positive electrode is formed as follows. That is, a mixture of LiCoO ₂ as a positive electrode active material 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 were mixed. In an atmosphere of an active gas (inert gas having a dew point of −60 ° C. or less; hereinafter, abbreviated as “inert gas”), they were mixed at a weight ratio of 2.4: 2 (mixture B ₁ ).

This mixture B ₁ was combined with the following chemical formulas 4, 5, and 6
10 parts by weight of the organic compound of 3: 5: 2, 1 part by weight of lithium tetrafluoroborate, 10 parts by weight of 1,2-dimethoxyethane and 10 parts by weight of γ-butyrolactone 10
Parts by weight in an inert gas atmosphere.
7: to obtain a mixture B ₂ by mixing 3 weight ratio.

[0054]

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[0055]

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[0056]

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[0057] b) was cast by screen coating onto a current collector to the mixture B ₂ to form an electron conducting layer on the aluminum surface of the above. Then, after dimethylformamide is completely removed in an inert gas atmosphere, the acceleration voltage 2
The composite positive electrode was formed by irradiating an electron beam at 50 kV and an electron dose of 12 Mrad. The thickness of the composite positive electrode film formed on the positive electrode current collector was 60 μm.

C) Next, in order to form an ion-conductive polymer compound on the composite positive electrode,
23 parts by weight of the organic compound of formula (4) in a weight ratio of 4: 4: 2, 4.5 parts by weight of lithium tetrafluoroborate, 24 parts by weight of 1,2-dimethoxyethane and 25 parts by weight of γ-butyrolactone And flow beads LE-108
0 (manufactured by Sumitomo Seika Co., Ltd.) 15.5 parts by weight, silica surface-treated with methyl group (Aero manufactured by AEROSIL Japan)
SIL R972D) was cast on the composite positive electrode by screen coating in an inert gas atmosphere, and then irradiated with an electron beam having an acceleration voltage of 250 kV and an electron dose of 8 Mrad in an inert gas atmosphere. Thereby, the ion conductive polymer compound layer was cured. 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 copolymer of carbon powder as a negative electrode active material and ethylene-propylene-cyclopentadiene as a binder (2
wt% solution) were mixed in an inert gas atmosphere at a weight ratio of 2: 5 (mixture C ₁ ).

This mixture C ₁ is combined with the above-mentioned chemical formulas 4, 5, and 6
10 parts by weight of the organic compound of 3: 5: 2, 1 part by weight of lithium tetrafluoroborate, 10 parts by weight of 1,2-dimethoxyethane and 10 parts by weight of γ-butyrolactone 10
Parts by weight in an inert gas atmosphere.
8: to obtain a mixture C ₂ by mixing 2 weight ratio.

[0061] The e) mixture C ₂ thereof was cast by screen coating on the anode current collector plate on consisting of rolled copper. Then, after xylene was completely removed in an inert gas atmosphere, the acceleration voltage was 250 kV and the electron dose was 12 Mr.
The composite negative electrode was formed by irradiating an electron beam of ad. The thickness of the composite negative electrode formed on the negative electrode current collector is 30
μm.

F) Next, in order to form an ion-conductive polymer compound on the composite negative electrode,
23 parts by weight of the organic compound of formula (4) in a weight ratio of 4: 4: 2, 4.5 parts by weight of lithium tetrafluoroborate, 24 parts by weight of 1,2-dimethoxyethane and 25 parts by weight of γ-butyrolactone And flow beads LE-108
0 (manufactured by Sumitomo Seika Co., Ltd.) 15.5 parts by weight, silica surface-treated with methyl group (Aero manufactured by AEROSIL Japan)
SIL R972D) and a mixture of 8 parts by weight were cast on the composite negative electrode by screen coating in an inert gas atmosphere, and then irradiated with an electron beam having an acceleration voltage of 250 kV and an electron dose of 8 Mrad in an inert gas atmosphere. Thus, the ion conductive polymer compound layer was cured. The thickness of the electrolyte layer thus obtained is 25 μm
Met.

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). Thus, a sheet-like battery of Example 1 of the present invention was produced.

(Comparative Example 1) Except that flow beads LE-1080 were not used in c) and f) of Example 1,
A sheet-shaped battery was produced in the same procedure as in Example 1.

(Example 2) The same as Example 1 except that miperon XM-220 (manufactured by Mitsui Petrochemical Co., Ltd.) was used in place of flow beads LE-1080 in c) and f) of Example 1. A sheet-shaped battery was produced according to the following procedure.

The electrode area of the sheet batteries of Example 1, Example 2 and Comparative Example 1 can be variously changed depending on the manufacturing process. In the present description, the electrode area is set to 100 cm ² . Things were made.

(External Short-Circuit Test) The sheet batteries of Examples 1, 2 and Comparative Example 1 were short-circuited in the air at 25 ° C., and after 5 minutes, an aluminum positive electrode current collector also serving as an exterior The surface temperature was measured. Table 2 shows the results.
At the same time, the current value flowing through the circuit was measured. The result is shown in FIG.

[0068]

[Table 2]

As can be seen from the results shown in Table 2 and FIG. 2, the sheet batteries of Examples 1 and 2 have excellent shutdown characteristics as compared with the sheet battery of Comparative Example 1. I understand. Therefore, the sheet-shaped battery of the present invention has higher safety in the whole battery than the conventional battery.

(Charge / Discharge Cycle Test) Using the sheet-shaped batteries of Examples 1, 2 and Comparative Example 1 at 25 ° C.
00μA / cm ² constant current / constant voltage charging and 100μA
/ Cm ² constant current discharge charge / discharge cycle test. A charge / discharge cycle test was performed with a charge end voltage of 4.1 V and a discharge end voltage of 2.7 V. FIG. 3 shows the relationship between the number of charge / discharge cycles and the battery capacity. 3. As can be seen from FIG. 3, the sheet-shaped battery of the present invention shows superior charge-discharge cycle characteristics as compared with the sheet-shaped battery of the comparative example. This is because, for example, no Li dendrite is generated around the composite negative electrode during the charge / discharge cycle, and there is no slight short circuit, and the charge / discharge cycle efficiency remains almost 100%. It is considered something.

Although not explicitly described in the present embodiment,
Furthermore, a thin electrode can be manufactured by various methods such as pressing, sputtering, suspension, coating, and the like, and the actual surface area of the active material in contact with the electrolyte layer and the current collector can be increased.

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

[0073]

As is apparent from the above description, since the electrolyte layer is made of the above-mentioned ionic conductive polymer compound, the shutdown characteristic is lower than that of the conventional ionic conductive polymer solid electrolyte. And ion conductivity,
Three of the mechanical properties satisfied the practicality at the same time.

Therefore, the following effects are obtained. 1) No long-term reliability without liquid leakage to the outside. 2) Extremely high safety even when abnormal current occurs. 3) High performance, high energy density, and extremely high workability. From these facts, there is an effect that the workability of the battery manufacturing process and the performance of the battery can be improved.

[Brief description of the drawings]

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

FIG. 2 shows a time change of a current value flowing through a circuit after an external short circuit in the sheet batteries of Example 1 and Example 2 and the sheet battery of Comparative Example 1.

FIG. 3 is a graph showing the relationship between the number of charge / discharge cycles and the battery capacity of the sheet batteries of Example 1 and Example 2 and the sheet battery of Comparative Example 1.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 positive electrode current collector 2 composite positive electrode, 3 electrolyte 4 composite negative electrode, 5 negative electrode current collector 6 sealing material

Continuation of the front page (56) References JP-A-2-40867 (JP, A) JP-A-4-245170 (JP, A) JP-A-4-33252 (JP, A) JP-A-3-20906 (JP) JP-A-3-95802 (JP, A) JP-A-3-177409 (JP, A) JP-A-61-281474 (JP, A) JP-A-5-67476 (JP, A) 2-291607 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/40 C08F 290/06

Claims (2)

(57) [Claims] 1. A battery comprising a composite positive electrode, an electrolyte and a composite negative electrode or a negative electrode mainly composed of an alkali metal, wherein the electrolyte contains at least one ionic compound in a dissolved state. , a polymer compound, in the battery in which the composite positive electrode and the composite negative electrode both have an ion-conductive polymer compound as a constituent material, the ion conductive polymer compound is described below, and
Hints further or, and battery, which comprises a. : At least an organic compound represented by the following chemical formula 1 or / and / or the following chemical formula 2 or / and the following chemical formula ◎ (R1, R2, and R3 are a hydrogen atom or a lower alkyl group having 1 or more carbon atoms, and m and n are m ≧ 1, n ≧ 0, n / m =
Indicates a number in the range 0 to 5. ) ◎ [Formula 2] (R4, R5 and R6 are a hydrogen atom or a lower alkyl group having 1 or more carbon atoms, and k and l are s ≧ 3, t ≧ 0, t / s =
Indicates a number in the range 0 to 5. ) ◎ 3 (R7 and R8 are a hydrogen atom or a lower alkyl group having 1 or more carbon atoms, and p1, q1, p2, q2, p3, and q3 are p1≥3, p2≥3, p3≥3, q1≥0, q2
.Gtoreq.0, q3 .gtoreq.0, q1 / p1 = a number in the range of 0 to 5, q2
/ P2 = a number in the range of 0 to 5, q3 / p3 = a number in the range of 0 to 5, and p1 + q1 ≥ 10, p2 + q2 ≥ 1
0, indicating that p3 + q3≥10. ): Ionic compound: Organic compound capable of dissolving ionic compound: Polyolefin powder: Inorganic compound whose surface is hydrophobized 2. The battery according to claim 1, wherein the means for forming the composite positive electrode, the electrolyte, and the composite negative electrode comprises irradiating an active ray to form the electrode and the electrolyte.