JP2000188099A - Manufacture of thin film type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a thin film type battery allowing effective prevention of a short circuit with high productivity. SOLUTION: This manufacturing method for a thin film type battery having a gel-like or solid-like electrolyte comprises (1) a positive electrode forming process and a negative electrode forming process wherein a positive electrode web and a negative electrode web are obtained by forming a positive electrode active material layer and a negative electrode active material layer on respective long conductive support; (2) a laminating process wherein a battery laminate web 21 is obtained by laminating the positive electrode web and the negative electrode web through a long separator web with their active material layers faced to each other; and (3) a cutting process wherein a battery laminate body is obtained by cutting the battery laminate web 21 in a direction nearly perpendicular to the longitudinal direction with a cutter having a cutting blade 22. In the cutting process, the cutting blade 22 is advanced from the side face direction of the battery laminate web 21 to cut it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film battery.

[0002]

2. Description of the Related Art Thin-film batteries, such as thin-film lithium secondary batteries, in which a positive electrode, a negative electrode, and an electrolyte layer in which an electrolyte is held in a polymer are each formed in a thin film form, usually use a negative electrode active material as an electrode substrate. The anode is formed by laminating a negative electrode formed thereon and a positive electrode formed on a separate electrode substrate with a positive electrode active material, with an electrolyte layer interposed and the respective active material layers facing each other. Generally, a separator is interposed between the positive electrode and the negative electrode for the purpose of preventing a short circuit between the positive electrode and the negative electrode, and in particular, the area of the separator is set smaller than that of the positive electrode or the negative electrode in order to prevent a short circuit at an edge portion of the laminate. It is configured to be large. In order to obtain such batteries of different sizes, there are great restrictions on the manufacturing process. That is, conventionally, a positive electrode, a negative electrode, and a separator having different sizes are prepared in advance, and then these are laminated.

[0003]

However, in the above-described conventional manufacturing method, since the sizes of the positive electrode, the negative electrode, and the separator are different, it is necessary to separately form the positive electrode, the negative electrode, and the separator and then stack them. There is. That is, not only is it necessary to handle the electrodes in a single sheet, but also it is necessary to perform accurate positioning, and thus there is a problem that productivity is poor and a defective rate is high. On the other hand, if the positive electrode, the negative electrode, and the separator are laminated in a state of a long raw material and then cut, the above problem itself can be solved, but in this case, the positive electrode, the negative electrode, and the separator have the same size. Therefore, the above-described problem of the occurrence of the short circuit is likely to occur.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, there is a problem in the cutting method, particularly in the cutting direction, in the method of cutting the raw materials after lamination. I found that. That is, when a laminate is cut from the top and bottom, such as a commonly used punching die, the end faces of the electrodes are easily crushed, resulting in a short circuit. Therefore, if the cutting blade is advanced from the side of the raw material and the cutting is performed from the side, even if the size of the separator is the same, a thin-film battery in which short circuit is effectively prevented is provided. They have found that they can be manufactured with high productivity, and have completed the present invention.

That is, the gist of the present invention is to (1) form a positive electrode raw material and a negative electrode raw material by forming a positive electrode active material and a negative electrode active material layer on different long conductive supports, respectively; Forming a negative electrode and forming a negative electrode; and (2) laminating the positive electrode raw material and the negative electrode raw material with a long separator raw material interposed therebetween in a direction in which an active material layer is opposed. A laminating step of obtaining a raw sheet, and (3) the step of:
A step of cutting in a direction substantially perpendicular to the longitudinal direction using a cutting device having a cutting blade to obtain a battery laminate, and a method of manufacturing a thin film battery having a gel or solid electrolyte. In the cutting step, the cutting blade is advanced from a side surface direction of the original battery stack to perform cutting.

In a preferred embodiment of the present invention, before the laminating step, there is provided an electrolyte component holding step of holding an electrolyte component in each of the positive electrode raw material and the negative electrode raw material. On this occasion,
Preferably, the electrolyte component is retained on the raw material of the separator. In a further preferred embodiment, the electrolyte component contains a non-aqueous solvent, an electrolyte salt and a monomer, and after application, the monomer is polymerized into a polymer, and the non-aqueous solvent and the electrolyte salt are retained in the polymer. To As a result, the viscosity of the electrolyte component can be reduced in the electrolyte component holding step, so that the handling becomes easy. In this case, it is preferable to have a polymerization step for polymerizing the monomer after the lamination step and before the cutting step, since the electrolyte in the laminate can be integrally formed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Step of Forming Positive Electrode and Step of Forming Negative Electrode In the present invention, first, a positive electrode active material layer and a negative electrode active material layer are formed on separate elongated conductive supports, respectively. . The active material layer for the positive and negative electrodes may be formed by any method, but it is preferable that the formed active material layer has a void that can be impregnated with an electrolyte component later. The same electrolyte as the electrolyte layer to be formed is formed in the gap, and this can be integrally formed with the electrolyte layer.

As a preferred method, there is a method in which the components constituting the active material are dispersed and coated with an appropriate solvent, the resultant is coated on a long conductive support, and then dried. Alternatively, a method of pressing or spraying the active material layer component on a support may be used. By adding a calendering step to the formed coating film, it is possible to consolidate the coating film and increase the filling amount of the active material. The degree of consolidation is determined by the balance between the amount of the active material filled and the ionic conductivity of the electrolyte portion filling the void.

[0009] An intermediate layer may be provided between the support and the active material layer in order to improve the adhesion between the support and the active material layer. For the same reason, the surface of the support may be subjected to a roughening treatment. Various coating methods such as slide coating, extrusion die coating, reverse roll, gravure, knife coater, kiss coater, microgravure, knife coater, rod coater, and blade coater can be applied. Of course,
It is also possible to combine these coating methods.

Also, depending on the wet state and viscosity of the paint,
It is also possible to transfer and apply the wet paint that has been applied to another support. The thickness of the formed active material layer is usually 1 μm or more, preferably 5 μm or more, and usually 500 μm or less, preferably 300 μm or less. If the thickness is too large, the rate characteristics tend to decrease, and if it is too thin, the capacity tends to decrease.

The long conductive support finally becomes the electrode base material of the battery. Therefore, usually metals or alloys such as aluminum and copper are used. It is preferable that the obtained raw materials of the positive electrode and the negative electrode are each held with an electrolyte component by means of coating or the like before laminating them, for ease of production. The electrolyte component may have the same composition as the electrolyte layer, or may have the same composition as the electrolyte layer by a predetermined treatment. For example, as a preferred embodiment, a liquid composed of a supporting electrolyte, a non-aqueous solvent, and a monomer is held as a component of the electrolyte by means such as coating, and then the monomer is polymerized by adding a polymerization treatment such as ultraviolet irradiation or heating. Then, a gel polymer electrolyte in which the formed polymer holds an electrolyte solution comprising an electrolyte salt and a non-aqueous solvent can be obtained. In the above-mentioned electrolyte component holding step, when the active material layer has a gap, at least a part of the electrolyte component applied in the above-mentioned electrolyte solution applying step becomes a raw material of the electrolyte filled in the gap.

(2) Laminating Step The raw materials of the positive electrode and the negative electrode are then laminated in a state where the active material layers are opposed to each other while being aligned in the longitudinal direction, to obtain a raw battery laminate. In this case, lamination is performed in a state where a long separator raw material is interposed between the positive electrode raw material and the negative electrode raw material. As a result, the battery can easily prevent a short circuit. At this time, it is preferable to impregnate the raw material of the separator with an electrolyte component since the electrolyte layer can be formed. As the electrolyte component to be impregnated in the separator, the same one as used in the electrolyte component holding step can be used.

Although it is possible to cause an electrolyte component to be present between the positive electrode raw material and the negative electrode raw material after lamination, as described above, it is preferable that the electrolyte component be retained on each raw material before lamination. More preferably, the electrolyte component is held in the raw separator. In any case, when the above-mentioned electrolyte component contains a non-aqueous solvent, an electrolyte salt and a monomer, it is preferable to add a polymerization step of polymerizing the monomer after lamination and before cutting the laminate raw material. preferable. As a result, it is possible to easily form a gel-like polymer electrolyte in which an electrolyte containing a non-aqueous solvent and an electrolyte salt is held in a polymer at a time. In this case, since the viscosity of the electrolyte component is relatively low, it is easy to apply or impregnate the electrolyte component. As a method of polymerization,
There are a method of irradiating ultraviolet rays, a method of applying heat, and the like, and a method of thermally polymerizing by applying heat is preferable because the polymerization reaction proceeds uniformly.

The above polymerization step can be provided after the cutting step described later, if necessary. The polymerization conditions at the time of the thermal polymerization need to consider the thermal stability and the like of each material forming the electrolyte layer, but are usually 60 to 100 ° C, preferably 70 to 90 ° C. The shorter the polymerization time is, the lower the polymerization time is, usually, 5 minutes or less, preferably 3 minutes or less, from the viewpoint of productivity, decomposition of materials, and the like.

Further, by forming the positive electrode layer, the electrolyte layer, and the negative electrode layer and then gelling the same, the gel electrolyte between the positive / negative electrode layer and the electrolyte layer has no interface, thereby improving the battery characteristics. Positive electrode / electrolyte layer /
Cut the laminate of the negative electrode into a desired size,
If necessary, this is further laminated to produce a thin-film battery.

(3) Cutting Step The battery laminate raw material obtained by stacking the positive electrode raw material and the negative electrode raw material is then completely cut in a direction substantially perpendicular to the longitudinal direction, and Is done. That is, by the cutting process,
The positive electrode raw material, the negative electrode raw material, and the separator raw material are cut at the same time to form a generally rectangular battery laminate. In order to prevent a short circuit between the edge of the positive electrode layer and the edge of the negative electrode layer during cutting, as shown in FIGS. 1 and 2, advance the cutting blade in the direction perpendicular to the lamination surface and from the side surface relative to the lamination. And cut it. FIG. 1 is a schematic perspective view showing an example of cutting using a disk-shaped rotary blade, and FIG. 2 is an example of cutting using a razor. In any case, the cutting blade (the rotary blade 22 or the razor 23) advances from the side surface of the laminate 21 to perform cutting. When a laminate is cut from the top and bottom, such as a punching die conventionally used, a short circuit is likely to occur.

As the cutting blade to be used, a disk-shaped rotary blade formed by molding a high-hardness fine particle such as a metal saw or diamond using a carbide or diamond tip with a resin or the like, a cutter knife or a razor-like blade, or the like can be used. It is possible to use a single round blade or a material obtained by making these materials ultra-hard. The cutting speed is preferably from 10 mm / min to 100 m / min, more preferably from 50 mm / min to 100 m / min.
If the speed is too slow, the productivity is extremely poor. If the speed is too fast, the edge accuracy tends to be poor and a short circuit tends to occur. The rotation speed of the rotary blade when using a rotary blade such as a metal saw is 100 rpm
m to 10,000 rpm, more preferably 300 rpm to
5000 rpm. Even if the rotation speed is too low or too high, the edge accuracy at the time of cutting is poor and short-circuiting tends to occur.

(4) Others The unit cell obtained through the cutting step is finally housed in a container such that the terminals electrically connected to the electrode substrate are exposed to the outside. At this time, a plurality of unit cells may be stored in the container. Usually, unit cells are stored in a container in a sheet form. Hereinafter, preferred embodiments of the present invention,
This will be described with reference to FIG.

FIG. 3 is a schematic diagram for explaining the manufacturing method of the present invention. The positive electrode raw material 1 obtained by applying the positive electrode active material layer coating material to a long metal foil and then drying it is as follows:
After being unwound from the roll 2, the coater 3 applies an electrolyte component containing an electrolyte salt, a non-aqueous solvent and a monomer. Similarly, the negative electrode raw material 4 obtained by applying the negative electrode active material layer coating material to a long metal foil and then drying is unwound from a roll 5, and then the same electrolyte component is applied by a coater 6. Applied. The long separator web 7 is also unwound from the roll 8 and the same electrolyte component is applied by the coater 9.

Each of the webs is pressed and stacked by a pair of rollers 10 having a slight interval. After the lamination, the laminated body is heated by the heater 11, the monomers in the electrolyte component are polymerized, and the electrolyte becomes a gel-like polymer electrolyte. Next, the laminate is
A rectangular sheet 1 cut in a direction substantially perpendicular to the long direction
3 is obtained. At this time, as a cutting method, a method in which a cutting blade is advanced from a side surface with respect to the laminate as shown in FIG. 1 or 2 is used.

The materials that can be used for the positive electrode, the negative electrode, and the electrolyte layer are not particularly limited, but a case of a lithium secondary battery using a preferably used polymer electrolyte will be described below. The positive electrode active material layer usually contains a positive electrode active material capable of inserting and extracting lithium ions and a binder. In the case of a binder with respect to 100 parts by weight of the active material, preferably 0.1 to 30 parts by weight, more preferably 1 to 1 part by weight.
5 parts by weight. If the amount of the binder is too small, a strong active material layer cannot be formed, and the object of the present invention in which the active material layer holds the active material cannot be achieved. If the amount of the binder is too large, not only has an adverse effect on the energy density and cycle characteristics, but also when the active material layer contains an electrolyte component, it is difficult to impregnate the electrolyte component because the amount of voids in the active material layer is reduced. .

Examples of the positive electrode active material include various inorganic compounds such as transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides. Here, Fe, Co, Ni, Mn, or the like is used as the transition metal. In particular,
Transition metal oxide powders such as MnO, V ₂ O ₅ , V ₆ O ₁₃ and TiO ₂ ; composite oxide powders of lithium and transition metals such as lithium nickelate, lithium cobaltate and lithium manganate; TiS ₂ , FeS And transition metal sulfide powders such as MoS ₂ . These compounds may be partially substituted with elements in order to improve their properties. In addition, polyaniline, polypyrrole, polyacene, disulfide compounds, polysulfide compounds,
Organic compounds such as N-fluoropyridinium salts can also be used. These inorganic compounds and organic compounds may be used as a mixture.

The active material of the positive electrode generally has a particle size of 1 to 3.
0 μm, especially 1 to 10 μm, rate characteristics,
Battery characteristics such as cycle characteristics are further improved. As the binder used for the positive electrode active material layer, polyethylene,
Alkane-based polymers such as polypropylene and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; polymers having a ring such as polystyrene, polymethylstyrene, polyvinylpyridine and poly-N-vinylpyrrolidone; Acrylic derivative polymers such as methyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinyl fluoride,
Fluorinated resins such as polyvinylidene fluoride and polytetrafluoroethylene; CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide; polyvinyl alcohol polymers such as polyvinyl acetate and polyvinyl alcohol; polyvinyl chloride and polyvinylidene chloride Various resins such as a halogen-containing polymer and a conductive polymer such as polyaniline can be used. In addition, a mixture of the above-described polymers, a modified substance, a derivative, a random copolymer,
Even an alternating copolymer, a graft copolymer, a block copolymer, or the like can be used. Also, inorganic compounds such as silicate and glass can be used. However, in order to achieve the object of the present invention, it is not preferable to use a resin that can be easily dissolved in an electrolytic solution. The weight average molecular weight of the resin is preferably 10,000 to 100,000.
0, more preferably 20,000 to 300,000. If it is too low, the strength of the coating film decreases, which is not preferable. If it is too high, the viscosity becomes high and it becomes difficult to form an active material layer.

The positive electrode active material layer may contain additives, such as a conductive material and a reinforcing material, exhibiting various functions such as a reinforcing material, a powder, and a filler, if necessary. The conductive material is not particularly limited as long as it can impart conductivity by being mixed in an appropriate amount with the above active material, but is usually carbon powder such as acetylene black, carbon black, graphite, and various metal fibers and foils. Is mentioned. Various inorganic materials as reinforcement,
Organic spherical or fibrous fillers can be used.

The thickness of the positive electrode active material layer is usually at least 1 μm, preferably at least 10 μm, usually at most 500 μm.
Preferably it is 200 μm or less. As the electrode base material of the positive electrode, generally, a foil such as a metal such as an aluminum foil or a copper foil, or an alloy is used. The thickness is usually 1 to 50 µm, preferably 1 to 3
0 μm. If the thickness is too small, the mechanical strength becomes weak, which causes a problem in production. If the thickness is too large, the capacity of the battery as a whole tends to decrease.

The negative electrode active material layer basically conforms to the structure of the positive electrode active material layer except that the active material is an active material for a negative electrode. Examples of the negative electrode active material used for the negative electrode include carbon-based active materials such as graphite and coke. These carbon-based active materials can be used in the form of a mixture with a metal, a salt thereof, or an oxide, or a coating. In addition, oxides such as silicon, tin, zinc, manganese, iron, and nickel, or sulfates, and lithium metal, Li-Al, Li-Bi-Cd, and Li
A lithium alloy such as -Sn-Cd, a lithium transition metal nitride, silicon, or the like can also be used. The particle size of the active material of these negative electrodes is usually preferably 1 to 50 μm, particularly preferably 15 to 30 μm, because battery characteristics such as initial efficiency, rate characteristics, and cycle characteristics are improved.

Next, the polymer electrolyte will be described. In the present invention, preferably, voids in the active material layers of the positive electrode and / or the negative electrode are filled with a gel-like polymer electrolyte, and ion conduction of lithium ions moves to the gel-like electrolyte layer through the gel-like electrolyte. As a result, the nonaqueous electrolytic solution of all of the positive electrode, the negative electrode and the electrolyte layer becomes gel-like, and a safe lithium secondary battery without liquid leakage can be obtained.

In the present invention, preferably, a fluid electrolyte which can be a gel polymer electrolyte is applied as an electrolyte component, and after the application, the polymer electrolyte is formed by a predetermined treatment. As such an electrolyte component, those containing an electrolytic solution composed of an electrolytic salt such as a lithium salt and a solvent and a monomer are preferable. In this case, the electrolytic solution is retained in the polymer by polymerizing the monomer later. Examples of such a polymer include those formed by polycondensation of polyester, polyamide, polycarbonate, and polyimide; those formed by polyaddition such as polyurethane and polyurea; acrylic derivative-based polymers such as polymethyl methacrylate; Although there are those produced by addition polymerization of polyvinyl acetate and the like such as polyvinyl acetate and polyvinyl chloride, etc., in the present invention, it is preferable that the active material layer is impregnated and polymerized. It is desirable to use a polymer produced by addition polymerization in which no by-product is generated during the polymerization.

The electrolyte salt contained in the electrolytic solution is stable as an electrolyte with respect to the positive electrode active material and the negative electrode active material, and transfers lithium ions to perform an electrochemical reaction with the positive electrode active material or the negative electrode active material. Any non-aqueous substance that can be used can be used. LiPF ₆ in particular, LiAsF _6, LiSbF _6, LiB
F ₄ , LiClO ₄ , LiI, LiBr, LiCl, Li
Examples include AlCl, LiHF ₂ , LiSCN, and LiSO ₃ CF ₂ . Of these, LiPF ₆ , Li
ClO ₄ is preferred. The content of these electrolyte salts in the electrolyte is generally 0.5 to 2.5 mol / l.

The electrolytic solution in which these electrolytes are dissolved is not particularly limited, but a nonaqueous solvent having a relatively high dielectric constant is preferably used. Specifically, cyclic carbonates such as ethylene carbonate and propylene carbonate, acyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, glymes such as tetrahydrofuran, 2-methyltetrahydrofuran and dimethoxyethane, γ-butyl lactone and the like Lactones,
One or a mixture of two or more of sulfur compounds such as sulfolane and nitriles such as acetonitrile can be mentioned. Of these, especially ethylene carbonate,
One or more mixed solutions selected from cyclic carbonates such as propylene carbonate, and non-cyclic carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are preferred. Further, those obtained by substituting a part of hydrogen atoms of these molecules with halogen or the like can also be used.

As the polymer constituting the gel electrolyte, a polymer capable of holding an appropriate amount of an electrolytic solution to form a gel is used. Usually, since the above-mentioned electrolytic solution has polarity, it is preferable that the polymer also has a certain degree of polarity. As aforementioned,
When a polymer is formed by addition polymerization, an impregnating liquid is prepared by mixing a monomer having at least one reactive unsaturated group in the molecule with the electrolyte usually in an amount of about 1 to 20% by weight. At this time, if the monomer has a highly polar group such as ethylene oxide, propylene oxide, phenylene oxide, phenylene sulfide, cyano, and carbonate in the molecule, it is possible to impart an appropriate polarity to the produced polymer, which is favorable. A good gel can be formed. The gel may be formed of only a linear polymer, but the number of reactive groups in the monomer is controlled to have a branched structure,
Forming a branched structure is preferable because mechanical properties and the like are improved.

Examples of the monomer having a reactive unsaturated group include acrylic acid, methyl acrylate, ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, polyethylene glycol monoacrylate, ethoxyethyl methacrylate, and methoxyethyl. Methacrylate, ethoxyethoxyethyl methacrylate, polyethylene glycol monomethacrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, 2-methoxyethoxyethyl acrylate, 2-ethoxyethoxyethyl acrylate, acrylonitrile , N-vinylpyrrolidone, diethylene glycol diacrylate, triethyl Glycol diacrylate,
Tetraethylene glycol diacrylate, polyethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and the like can be used. Alternatively, they may be used in combination.

As a method for polymerizing these monomers, there are methods using heat, ultraviolet rays, electron beams, etc., and a method using heat which is easy to integrally form the positive electrode layer / electrolyte layer / negative electrode layer is effective. In this case, in order for the reaction to proceed effectively, a polymerization initiator that reacts with heat may be added to the electrolyte to be impregnated. Usable thermal polymerization initiators include azo compounds such as azobisisobutyronitrile, dimethyl 2,2'-azobisinbutyrate, benzoyl peroxide, cumene hydroperoxide, t-butylperoxy-2-ethylhexano. Peroxides such as ate can be used, and those which are preferable in terms of reactivity, polarity, safety, etc. may be used alone or in combination.

In the present invention, a solid electrolyte can be used as the electrolyte. In this case, various conventionally known electrolytes can be used. The electrolyte of the electrolyte layer is impregnated in a separator made of a porous film or a nonwoven fabric. The thickness of the electrolyte layer is usually 1 μm
Above, preferably 5 μm or more, and usually 500 μm or less, preferably 200 μm or less. If it is too thick, the capacity tends to decrease, and if it is too thin, the insulation tends to decrease.

[0035]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition,
In the following, “parts” means “parts by weight” unless otherwise specified. The raw materials used in the examples and comparative examples were each processed as follows before use. That is, the powder is vacuum-dried at 240 ° C. for 24 hours, and
After drying at 10 ° C. for 4 hours, the monomer was dehydrated with a molecular sieve.

Example 1 First, a paint for a positive electrode active material layer and a paint for a negative electrode active material layer were prepared according to the following compositions. At this time, the following were used as raw materials for the positive electrode paint and the negative electrode paint.

[0037]

Table 1 Positive electrode active material LiCoO ₂ powder (manufactured by Nippon Chemical Co., Ltd.) Conductive material Acetylene black (manufactured by Denki Kagaku Kogyo) Negative electrode active material SFG15: graphite (manufactured by TIMCAL) binder Polyvinylidene fluoride (manufactured by Kureha Chemical) Solvent N-methyl Pyrrolidone (Mitsubishi Chemical)

[0038]

[Table 2] Coating composition of positive electrode active material layer LiCoO ₂ 90.0 parts Acetylene black 5.0 parts Polyvinylidene fluoride 5.0 parts N-methylpyrrolidone 100.0 parts Negative electrode active material layer coating composition SFG15 90.0 parts Polyfluorinated Vinylidene 10.0 parts N-methylpyrrolidone 100.0 parts

Each of the above materials was kneaded and dispersed in a ball mill for 8 hours to form a coating. Next, the coating for the positive electrode active material layer was coated on a long aluminum foil having a thickness of 20 μm to a thickness of 100 μm by an extrusion day coating method.
And dried to obtain a positive electrode raw material. Further, the negative electrode active material layer coating material was applied on a long copper foil having a thickness of 20 μm using a doctor blade so that the film thickness became 150 μm, and dried to obtain a negative electrode raw material. Thereafter, each active material layer was dried at 240 ° C.

The sheet provided with the above-mentioned positive electrode / negative electrode active material layer on the current collector was subjected to a calendering (pressure) treatment so that the final film thickness was 75 μm for the positive electrode and 60 μm for the negative electrode. Each of the obtained positive and negative electrode raw materials was impregnated with the following electrolyte components, and was impregnated with the same electrolyte components in a thickness of 20 μm.
Was prepared.
The positive electrode raw material and the negative electrode raw material were fed out between two rolls with the active material layers facing each other and with the above-mentioned separator interposed therebetween, and laminated to obtain a battery laminate raw material. The obtained laminate raw material was heated at 90 ° C. for 3 minutes to polymerize the monomer, and the electrolyte components in the active material layer and the electrolyte layer were gelled to obtain a sheet having a polymer electrolyte.

[0041]

[Table 3] Electrolyte component Electrolyte PC: Propylene carbonate (manufactured by Mitsubishi Chemical Corporation) Supporting electrolyte LiClO4 (manufactured by Wako Pure Chemical Industries) Additive 1,6-Dioxaspiro [4,4] nonane-2,7-dione (hereinafter referred to as “spiro”) )) (Manufactured by Aldrich) Monomer Photomer 4050 Photomer 4158 (polyethylene oxide resin having an acrylic terminal at each end (manufactured by Henkel)) Crosslinking initiator Trignox21 (manufactured by Kayaku Aguzo)

[0042]

Table 4 Composition of electrolyte components 78 parts of PC 7 parts of LiClO ₄ 5 parts of Spiro 6.7 parts of Photomer 4050 3.3 parts of Photomer 4158 3.3 parts of Trignox 21 1.0 part

Using a rotary blade, the above-mentioned laminate was cut by moving the blade from the side of the laminate. The rotary blade uses a super hard metal saw and the cutting speed is 200mm
/ Min, and the number of revolutions was 1000 rpm. The size of the resulting laminate was 40 mm × 50 mm. afterwards,
Terminals were attached to the positive electrode and the negative electrode, and sealed in a flexible vacuum pack to produce 20 thin-layer lithium secondary batteries, which were evaluated. The evaluation was performed on the number of batteries in which a short circuit occurred after charging and discharging. Further, the battery was taken out from the battery pack, and the edge portion was observed under a microscope. The results are shown in Table 1.

(Comparative Example 1) Twenty thin-layer batteries were prepared and evaluated in the same manner as in Example except that cutting was performed by press cutting using a mold. The results are shown in Table 1.

[0045]

[Table 5]

[0046]

Industrial Applicability The lithium secondary battery of the present invention is a method for producing a lithium secondary battery using a gel electrolyte having a high energy density, excellent cycle characteristics, and suppressing problems such as liquid leakage. And the short circuit can be effectively suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of cutting in the present invention.

FIG. 2 is a schematic perspective view showing another example of cutting in the present invention.

FIG. 3 is a schematic view showing an outline of the production method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive raw material 2,5,8 Roll 3,6,9 Coater 4 Negative raw material 5 Separator raw material 12 Cutter 21 Laminated material raw material 22 Rotating blade 23 Razor

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 5H014 AA04 AA06 BB04 BB08 BB11 BB17 CC01 EE02 5H029 AJ14 AK02 AK03 AK05 AK16 AL01 AL02 AL07 AL08 AL12 AM03 AM04 AM05 AM07 AM16 BJ04 CJ04 CJ11 CJ13 CJ09 CJ12 DJ

Claims (5)

[Claims] 1. A positive electrode forming step in which a positive electrode active material material and a negative electrode active material layer are respectively formed on different elongated conductive supports to obtain a positive electrode raw material and a negative electrode raw material, and a negative electrode formation. And (2) converting the positive electrode raw material and the negative electrode raw material into
A laminating step of laminating the raw material laminate by interposing the elongated raw material in a direction in which the active material layers face each other, and (3) having a cutting blade for the raw battery laminate. Using a cutting device, a cutting step of obtaining a battery laminate by cutting in a direction substantially perpendicular to the long direction, a method for producing a thin film battery having a gel or solid electrolyte, In the process, the cutting blade is advanced by moving the cutting blade from a side surface direction of the original battery stack to perform cutting. 2. The method for producing a thin film battery according to claim 1, further comprising an electrolyte component holding step of holding an electrolyte component in each of the positive electrode raw material and the negative electrode raw material before the laminating step. 3. The method for producing a thin-film battery according to claim 2, wherein in the electrolyte component holding step, the electrolyte component is further held on the raw separator. 4. An electrolyte component containing a non-aqueous solvent, an electrolyte salt and a monomer, and polymerizing the monomer to form a polymer after coating, wherein the non-aqueous solvent and the electrolyte salt are retained in the polymer. 3. The method for producing a thin-film battery according to item 1. 5. The method according to claim 4, further comprising a polymerization step for polymerizing the monomer after the laminating step and before the cutting step.