JPH11121035A - Manufacture of solid electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily mass-produce a solid electrolyte secondary battery having high energy density and low internal resistance. SOLUTION: A spiral electrode 10 comprising a belt-like positive electrode 1 and a belt like negative electrode 2 using a lithium storage compound, and a separator 3 is contained in a battery can 15, insulation plates 16a, 16b are provided on both up and down faces of the electrode 10, a positive electrode lead 17 is led out from a positive electrode collector and is welded to a battery lid 18, and a negative electrode lead 19 is led out of a negative electrode collector and is welded to a battery can 15. Nonaqueous electrolyte containing a thermal polymerization initiator and a polymerizing compound are permeated into the battery can 15 by reduced pressure immersion. By caulking the battery can 15 via an insulative sealing gasket 21, an safety valve device 22 and the battery lid 18 are fixed so as to maintain airtightness in the battery. Thereafter, the nonaqueous electrolyte is heated under a predetermined condition so as to form an electrolyte layer to make a cylindrical solid electrolyte battery 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a solid electrolyte secondary battery.

[0002]

2. Description of the Related Art A secondary battery based on the transfer of lithium ions between a positive electrode and a negative electrode has a simpler structure than a lead storage battery or a nickel cadmium battery, and has the highest electromotive force in theory. It has received a lot of attention. In the 1970's, a secondary battery using lithium metal as a negative electrode active material and titanium disulfide as a positive electrode active material was used. In 1987, a secondary battery in which the positive electrode active material of the secondary battery was replaced with molybdenum disulfide was used. Commercially available. Further, in 1987, a secondary battery using lithium metal as a negative electrode active material and polyaniline as a positive electrode active material was commercialized.

[0003]

In recent years, research on gelled organic electrolytes that have gelled and semi-solidified electrolytes and have no liquid leakage has been actively conducted. This gel electrolyte has already been proposed in JP-A-54-104541. In these patent publications, a gel electrolyte is obtained by dissolving polymethyl methacrylate or the like in an organic electrolyte and polymerizing a monomer. When such a gelled semi-solid electrolyte is used, no battery leakage is observed, but the battery characteristics are clearly reduced.

[0004] This is because, compared to a liquid electrolyte, the gel electrolyte has an order of magnitude lower conductivity, and the electrolyte does not sufficiently penetrate into the electrode, thereby increasing the interfacial resistance on the electrode surface and increasing the discharge current density. It is considered that when the value is increased, the reaction does not sufficiently reach the inside of the electrode. In particular, the latter interfacial resistance poses a major problem when actually producing a battery.

Japanese Patent Publication No. Sho 60-112261 discloses a method of reducing the interfacial resistance of an electrode when a battery is actually manufactured using a solid electrolyte by inserting a solid electrolyte between a positive electrode and a negative electrode, A heat treatment is proposed. However, in this method, since the electrolyte component does not sufficiently penetrate into the grain boundaries, it has been difficult to sufficiently reduce the interface resistance.

Further, a method of applying a solid electrolyte monomer solution or a gel electrolyte monomer solution to each of the positive electrode and the negative electrode, solidifying them by means of light irradiation or the like, and then bonding the positive electrode and the negative electrode to produce a solid electrolyte battery is also employed. ing. However, in this method, entrapment of an atmospheric gas, generation of an interface at a bonded portion, and the like cannot be avoided during the bonding. Also, as a major problem of this method, if the thickness of the solid electrolyte layer is too thin, short-circuit is likely to occur, and if it is thick, the energy density per volume is low, and the merit of the solid electrolyte has been reduced. .

Further, JP-A-57-55067 and JP-A-57-55068 disclose an organic electrolytic solution containing a polymethacrylic ester after lithium and a positive electrode containing an organic electrolyte are incorporated in a battery container. And a step of heating and gelling the electrolyte before or after sealing the battery. However, many polymer matrices for solid electrolytes, such as polymethacrylic acid esters, cannot hold a large amount of electrolyte solution, and therefore have low conductivity, and inevitably deteriorate battery characteristics.

Further, Japanese Patent Application Laid-Open No. 5-3036 discloses that
A method for obtaining a sheet-shaped solid electrolyte battery by a thermal polymerization reaction is disclosed. However, this method cannot be applied to relatively large-capacity batteries such as cylindrical and square batteries, and cannot use conventional production lines such as electrolytic-type cylindrical battery production lines at all. The installation of a new mass production line led to an increase in battery costs. Furthermore, when the polymerizable electrolyte is injected under reduced pressure, it is not possible to reduce the pressure only in the sheet case.
This has led to a large drop in tact.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method for relatively easily mass-producing a solid electrolyte secondary battery having a high energy density and a low internal resistance. It is in.

[0010]

According to a first aspect of the present invention, there is provided a method for manufacturing a solid electrolyte secondary battery, comprising the steps of: combining a negative electrode using lithium or a compound that absorbs lithium and a positive electrode via a separator; After inserting the battery member in a shape or a laminate into the hard case, a non-aqueous electrolyte solution containing a thermal polymerization initiator and a polymerizable compound is infiltrated into the battery case by vacuum injection, and the non-aqueous electrolyte solution is It is characterized by forming an electrolyte layer by heating.

According to the first aspect of the present invention, the operation of liquid injection under reduced pressure is simplified, and the mass production of a solid electrolyte secondary battery with a short tact time and low production cost is possible only by solidifying the electrolyte layer by thermal polymerization. It became. The absolute pressure at the time of the reduced pressure injection operation is preferably 1 to 21 cmHg. If the absolute pressure exceeds 21 cmHg, the gel electrolyte does not sufficiently penetrate into the member. If the absolute pressure is less than 1 cmHg, the low-boiling solvent in the gel electrolyte volatilizes instantaneously, causing problems such as a change in composition and generation of bubbles.

Further, according to the manufacturing method of the first aspect, the problem of the interface at the time of bonding the positive electrode and the negative electrode is eliminated, and the impedance inside the battery is reduced, so that the capacity deterioration is small even at the discharge at a high current density. Cycle characteristics are also improved. Further, it is possible to solve the difficulty of handling sticky electrodes in a mass production line. Therefore, the manufacturing process is simple and the existing mass production line can be diverted, so that the battery manufacturing cost can be significantly reduced.

According to a second aspect of the present invention, in the method for manufacturing a solid electrolyte secondary battery according to the first aspect, the battery case is a square battery case, and the battery member is inserted into the square battery case. After sealing the prismatic battery case with a battery lid having an inlet previously opened, the non-aqueous electrolyte is injected under reduced pressure into the prismatic battery case through the electrolyte inlet. According to this manufacturing method, the pressure can be reliably reduced, the adhesion of the non-aqueous electrolyte to the battery lid is prevented, and the yield is improved.

According to a third aspect of the present invention, in the method for manufacturing a solid electrolyte secondary battery according to the first or second aspect, the content of the non-aqueous electrolyte is adjusted to 200 weight of a polymerizable compound having a thermally polymerizable functional group. % Or more. In this case, the content of the nonaqueous electrolyte is preferably 200 to 300% by weight, more preferably 300 to 1000% by weight. By doing so, the conductivity can be kept substantially equal to that of the electrolytic solution while being a solid electrolyte.

The polymerizable compound used in the present invention contains a non-carbon hetero atom such as an oxygen atom, a nitrogen atom, and a sulfur atom in the molecule. The polymer gel electrolyte is obtained by dissolving a polymerizable compound containing a hetero atom in a non-aqueous electrolyte and causing a polymerization reaction. This polymerization reaction is preferably performed in an inert gas atmosphere. In addition, the type of the polymerizable compound used in the present invention is not particularly limited, and includes those that cause a thermal polymerization reaction to obtain a polymer, and include a monofunctional monomer that can form a crosslinked polymer matrix. Combinations with polyfunctional monomers are preferred.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a solid electrolyte secondary battery according to the first, second or third aspect, wherein a (meth) acrylate monomer and / or a prepolymer thereof is used as the polymerizable compound. . In addition, (meth) acrylate in this specification means acrylate or methacrylate.

As the monofunctional acrylate, alkyl (meth) acrylate [methyl (meth) acrylate,
Butyl (meth) acrylate, trifluoroethyl (meth) acrylate, etc.]; alicyclic (meth) acrylate;
Hydroxyalkyl (meth) acrylate [hydroxyethyl acrylate, hydroxypropyl acrylate, etc.]; hydroxypolyoxyalkylene (oxyalkylene group preferably has 1 to 4 carbon atoms) (meth) acrylate [hydroxypolyoxyethylene (meth) acrylate, hydroxy Polyoxypropylene (meth) acrylate, etc.] and: alkoxyalkyl (alkoxy group preferably has 1 to 4 carbon atoms) (meth) acrylate [methoxyethyl acrylate, ethoxyethyl acrylate, etc.].

Specific examples of other (meth) acrylates include, for example, methyl ethylene glycol (meth) acrylate, ethyl ethylene glycol (meth) acrylate, propyl ethylene glycol (meth) acrylate, ethoxydiethylene glycol acrylate, methoxyethyl acrylate, and methoxydiethylene glycol. Alkyl ethylene glycol (meth) acrylates such as methacrylate, methoxy triethylene glycol acrylate, methoxy triethylene glycol methacrylate, and methoxy tetraethylene glycol methacrylate; alkyl propylene glycol (meth) such as ethyl propylene glycol acrylate, butyl propylene glycol acrylate, and methoxy propylene glycol acrylate Acrylate, and the like.

The (meth) acrylate may contain a heterocyclic group, such as oxygen, nitrogen,
It is a heterocyclic residue containing a hetero atom such as sulfur. The type of the heterocyclic group contained in the (meth) acrylate is not particularly limited, but for example, a furfuryl group,
Furfuryl (meth) having a tetrahydrofurfuryl group
Acrylate and tetrahydrofurfuryl (meth) acrylate are preferred. Other (meth) acrylates having a heterocyclic group include furfurylethylene glycol (meth) acrylate, tetrahydrofurfurylethylene glycol (meth) acrylate, furfurylpropylene glycol (meth) acrylate, and tetrahydrofurfurylpropylene glycol (meth) acrylate And alkylene glycol acrylates having a furfuryl group or a tetrahydrofurfuryl group.

Further, examples of the polyfunctional (meth) acrylate compound include a monomer or a prepolymer having two or more (meth) acryloyl groups. Examples of the polyfunctional (meth) acrylate include ethylene glycol dimethacrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol (meth) acrylate, triethylene glycol (meth) acrylate,
Examples include tripropylene glycol diacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, trimethylolpropane tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

In the present invention, after a battery member in which a negative electrode using lithium or a compound that absorbs lithium and a positive electrode are combined via a separator is inserted into a hard case, the (meth) acrylate monomer and / or its By infiltrating the non-aqueous electrolyte containing a polymer into the battery case and heating the battery member, the holding power of the non-aqueous electrolyte is increased, and a stable electrolyte for charge and discharge is obtained. Therefore, the inside of the battery has a low impedance,
Even when discharging at a high current density, capacity deterioration is reduced, and cycle characteristics are improved.

According to a fifth aspect of the present invention, in the method for manufacturing a solid electrolyte secondary battery, the (meth) acrylate monomer and / or a prepolymer thereof has a molecular weight of 1
000 or less. In this case, the molecular weight is preferably 500 or less, more preferably 300 or less,
Thereby, the non-aqueous solvent in the polymer gel electrolyte does not ooze out and can be handled as a stable gel electrolyte.

[0023] The method for manufacturing a solid electrolyte secondary battery according to claim 6 is the method according to any one of claims 1 to 5,
The electrolyte layer is formed of a crosslinked polymer matrix ion-conductive polymer gel electrolyte. By doing so, the effect of preventing the non-aqueous solvent in the polymer gel electrolyte from seeping out is enhanced, and the gel electrolyte can be handled as a more stable gel electrolyte.

To form a crosslinked polymer matrix,
Combinations of monofunctional and polyfunctional monomers are particularly preferred. When a monofunctional monomer and a polyfunctional monomer are used in combination, when the polyfunctional monomer is a polyfunctional (meth) acrylate compound, the polyfunctional (meth) acrylate
The amount of the acrylate compound added is 4 to the non-aqueous electrolyte.
% By weight, preferably 0.05 to 2% by weight.

As the thermal polymerization initiator, azobisisobutyronitrile, azobisvaleronitrile, benzoyl peroxide, lauroyl peroxide, ethyl methyl ketone peroxide, bis- (4-
(t-butylhexyl) peroxydicarbonate, diisopropyl peroxydicarbonate and the like. Of these, peroxydicarbonate compounds are preferred. That is, the method for producing a solid electrolyte secondary battery according to claim 7 is characterized in that, in any one of claims 1 to 6, a peroxydicarbonate-based compound is used as the thermal polymerization initiator. .

By using the peroxydicarbonate compound, a solid electrolyte secondary battery having excellent potential stability and improved cycle characteristics can be easily obtained. Also,
The amount of the thermal polymerization initiator to be used is usually 0.1 to 0.1 based on the (meth) acrylate monomer and / or the prepolymer.
It is 10% by weight, preferably 0.5 to 7% by weight.

[0027] The method for manufacturing a solid electrolyte secondary battery according to claim 8 is the method according to any one of claims 1 to 7, wherein
The heat treatment is performed within a temperature range of 40 to 120 ° C. By doing so, it is possible to manufacture a battery with higher stability, lower internal impedance, and no oozing of the electrolyte from the gel electrolyte. When the heating temperature during the thermal polymerization is lower than 40 ° C., the progress of gelation becomes incomplete, and seepage of the liquid is observed. In particular, when applying heat polymerization to a battery having a relatively large capacity such as a cylindrical or rectangular battery, heat must be evenly transmitted to the inside of the battery. For this reason, good results are obtained at a set temperature 20 to 30 ° C. higher than a general thermal polymerization start temperature, but when the temperature exceeds 120 ° C., a side reaction occurs inside the battery, and a low-boiling-point solvent is vaporized. An increase in internal impedance is observed, which has a serious adverse effect on battery cycle characteristics.

The electrolytic solution is a solution in which a lithium salt is dissolved in an organic solvent. The organic solvent dissolves the lithium salt well, and does not need to react with the electrode constituents and the lithium salt. Is preferred. Specifically, propylene carbonate, ethylene carbonate, butylene carbonate, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, triethyl phosphite, triethyl phosphate, dimethylformamide, dimethylacetamide,
One or a mixture of two or more organic solvents such as dimethyl sulfoxide, dioxane, dimethoxyethane, polyethylene glycol, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, methylglyme, methyltriglyme, dimethylcarbonate, diethylcarbonate, and methylethylcarbonate Is mentioned.

Specific examples of lithium salts suitable as an electrolyte used in the battery of the present invention include, for example, LiBF ₄ , LiAsF ₆ , LiPF ₆ , and LPF as Lewis acid double salts.
iSbF _{6 and the} like. Examples of the sulfonate include LiCF ₃ SO ₃ and LiN (CF ₃ S
O ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C
H ₃ ) (CF ₃ SO ₂ ) ₂ , LiC ₂ F ₅ SO ₃ , Li
N (C ₂ F ₅ SO ₂ ) _{2 and the} like, but are not limited thereto.

Other examples of the electrolyte salt according to the present invention include Li
ClO ₄ , LiCF ₃ CO ₃ , NaClO ₃ , NaBF
_{4, NaSCN, KBF 4, Mg} (ClO 4) 2, Mg
(BF ₄ ) _{2 and the} like, but are not limited thereto, and are not particularly limited as long as they are used for a normal non-aqueous electrolyte. Further, a mixture of the Lewis acid double salt electrolyte and a sulfonate electrolyte may be used, and another electrolyte salt may be further mixed.

Examples of the non-aqueous electrolyte include a solution in which an electrolyte salt is dissolved in a non-aqueous solvent. The concentration of the electrolyte salt in the non-aqueous electrolyte is usually 1.0 to 1.0 with respect to 1 liter of the non-aqueous solvent.
7.0 mol is preferable, and 1.0 to 5.0 mol is particularly preferable.

As the positive electrode active material used in the battery of the present invention, TiS ₂ , MoS ₂ , Co ₂ S ₅ , V ₂ O ₅ , M
Transition metal oxides such as nO ₂ and CoO ₂ , transition metal chalcogen compounds, and composites thereof with Li (Li composite oxide: LiMnO ₂ , LiMn ₂ O ₄ , LiCo
O ₂ , LiNiO _2, etc.).

As the conductive agent, a one-dimensional graphite compound, which is a thermal polymer of an organic substance, carbon fluoride, graphite, or a conductive polymer having an electric conductivity of 10 ⁻² S / cm or more, specifically, Examples include polymers such as polyaniline, polypyrrole, polyazulene, polyphenylene, polyacetylene, polyphthalocyanine, poly-3-methylthiophene, polypyridine, and polydiphenylbenzidine, and derivatives thereof. Among these, it is preferable to use a conductive polymer that exhibits high cycle characteristics even at a discharge depth of 100% and is relatively resistant to overdischarge as compared with inorganic materials.

In the present invention, for example, polyvinylidene fluoride may be used as the binder (binder). Further, the electrode can be produced by supporting the above-mentioned positive electrode active material, conductive agent, binder, and the like on a current collector by a method such as application, adhesion, and pressure bonding as necessary.

As the negative electrode material used in the battery of the present invention, intercalation capable of occluding lithium ions such as metals such as lithium, lithium aluminum alloy, lithium tin alloy and lithium magnesium alloy, carbon and carbon-substituted products, and tin oxide. Substance and the like.

Examples of the carbonaceous negative electrode active material used in the battery of the present invention include graphite, pitch coke, fired products of synthetic polymers and natural polymers. In particular,
(1) Insulating or semiconducting carbon obtained by baking a synthetic polymer such as phenol or polyimide or a natural polymer in a reducing atmosphere at 400 to 800 ° C., (2) Coal, pitch, synthetic polymer or natural polymer. 800 molecules
Conductive carbon obtained by firing in a reducing atmosphere at 1300 ° C., (3) coke, pitch, synthetic polymer,
Examples thereof include those obtained by baking a natural polymer at a temperature of 2000 ° C. or more in a reducing atmosphere, and graphite-based carbon bodies such as natural graphite.

The carbon body can be formed into a sheet by a wet papermaking method from the carbon body and the binder, or by a coating method using a coating material in which an appropriate binder is mixed with a carbon material. it can. The electrode is a sheeted carbon body as a current collector,
If necessary, it can be produced by carrying by a method such as application, adhesion, and pressure bonding.

Examples of the positive electrode current collector used in the battery of the present invention include metal sheets such as stainless steel, gold, platinum, nickel, aluminum, molybdenum, and titanium, metal foil, metal net, punching metal, expanded metal, and the like.
Alternatively, a mesh or a nonwoven fabric made of metal-plated fiber, metal-deposited wire, metal-containing synthetic fiber, or the like can be used. Among these, aluminum and stainless steel are preferable, and aluminum is particularly preferable in terms of lightness and electrochemical stability.

The surfaces of the positive electrode current collector layer and the negative electrode current collector layer are preferably roughened. Polishing, blasting,
There is chemical or electrochemical etching. In particular, in the case of stainless steel, when the blast treatment is aluminum, the etching treatment is preferable.

Examples of the separator used in the battery of the present invention include glass fibers, filters, nonwoven fabric filters made of polymer fibers such as polyester, Teflon, polyflon, polypropylene, and polyethylene, and mixtures of glass fibers and these polymer fibers. And the like.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Parts and% indicate parts by weight and% by weight, respectively. As the non-aqueous solvent and the electrolyte salt, use a battery grade that has been sufficiently purified to a water content of 20 ppm or less and further deoxygenated and denitrified, and all operations are performed in an inert gas atmosphere. Was.

Example 1 [Preparation of positive electrode] 3 parts of polyvinylidene fluoride was dissolved in 38 parts of N-methylpyrrolidone, and LiC was added thereto as an active material.
50 parts of oO ₂ and 9 parts of graphite as a conductive agent were added and mixed and dispersed in a homogenizer under an inert gas atmosphere to prepare a coating for a positive electrode. This was applied to both surfaces of a 20 μm-thick aluminum foil in the air, dried at 125 ° C. for 30 minutes, and then compression molded to obtain a belt-shaped positive electrode. The thickness of the mixture after molding is the same on both sides as the film thickness of 70 μm, and the width of the electrode is 4 μm.
The length was 0.5 mm and the length was 660 mm.

[Preparation of Negative Electrode] 3 parts of polyvinylidene fluoride was dissolved in 58 parts of N-methylpyrrolidone, 40 parts of a coke calcined product at 2500 ° C. was added, and mixed and dispersed under an inert gas atmosphere by a roll mill method. A negative electrode paint was prepared. This was put in the air using a wire bar to a thickness of 20μ.
m, and dried at 100 ° C. for 15 minutes, followed by compression molding to obtain a belt-shaped negative electrode. The thickness of the mixture after molding was the same on both sides as the film thickness of 80 μm, and the width of the electrode was 41.5.
mm and the length were 720 mm.

[Preparation of spiral electrode (see FIG. 1)] Strip-shaped positive electrode 1, strip-shaped negative electrode 2, thickness 25 μm and width 33 mm
The negative electrode 2, the separator 3, the positive electrode 1, and the separator 3 were laminated in this order on the separator 3 composed of a microporous polypropylene film, and the laminated body was spirally wound many times as shown in FIG. The spirally wound electrode 10 having an outer diameter of 19.6 mm was produced by fixing the outermost winding end portion with an adhesive tape 4. The pressure-sensitive adhesive tape 4 used was a polyester film having a thickness of 25 μm as a support, and was coated with a silicone-based pressure-sensitive adhesive and had a width of 40 mm and a length of 41 mm.

[Preparation of Cylindrical Solid Electrolyte Battery (See FIG. 2)] (1) As shown in FIG. 2, the spiral electrode 10 was housed in a nickel-plated iron battery can 15. Spiral electrode 1
Insulating plates 16a and 16b are provided on the upper and lower surfaces of the negative electrode lead 17, and an aluminum positive electrode lead 17 is led out of a positive electrode current collector and welded to a battery cover 18, and a nickel negative electrode lead 1 is provided.
9 was taken out from the negative electrode current collector and welded to the battery can 15. The thermopolymerizable solution was injected into the battery can 15 under reduced pressure at an absolute pressure of 11 cmHg.

The above-mentioned thermopolymerizable solution is a 2.0 M LiPF ₆ solution obtained by dissolving LiPF _{6 in} a mixture of propylene carbonate / ethylene carbonate / dimethyl carbonate (2/5/3: volume ratio). 86 parts, as a monofunctional monomer,
Ethyl diethylene glycol methacrylate (molecular weight 1
88) 13.8 parts of P as a polyfunctional monomer
It was obtained by mixing and dissolving 0.2 part of O-modified trimethylolpropane triacrylate (molecular weight: 470) and 0.056 part of di-myristyl peroxydicarbonate as a thermal polymerization initiator. In this case, the ratio (weight basis) of the electrolytic solution to the monomer is [86 (13.8 + 0.2)]
× 100 = 614%.

By caulking the battery can 15 via an insulating sealing gasket 21 coated with asphalt on the surface, the safety valve device 22 having a current cutoff mechanism and the battery lid 18 are fixed to maintain airtightness in the battery. I let it. Then, it was stored under a temperature environment of 70 ° C. for 10 hours to gel the internal electrolyte. With the above configuration, the diameter is 20 mm,
A cylindrical solid electrolyte battery 20 having a height of 50 mm was produced.

Example 2 (see FIG. 3) A positive electrode coated on both sides in the same manner as in Example 1 was used.
The positive electrode 31 was punched out to 1 mm, and the positive electrode 31 was packed in a separator 33 made of a polypropylene pore filter having a thickness of 25 μm to prepare 16 positive electrode members having an outer size of 42 mm × 32 mm. On the other hand, the negative electrode 32 coated in the same manner as in Example 1 was punched into an outer size of 42 mm × 32 mm to prepare 17 negative electrode members. These positive electrode member and negative electrode member are alternately laminated so that the negative electrode 32 is located on the outermost surface, and both sides of the laminate are sandwiched between nickel-plated stainless steel plates 34 having a thickness of 0.1 mm, It was bundled with a tape 36 to form a laminated battery member.

The laminated battery member was housed in a nickel-plated iron square battery can 35 having an outer dimension of 48 mm × 34 mm × 8 mm. An aluminum positive electrode lead 37 pre-welded to the positive electrode current collector is led out from the positive electrode current collector, and is welded to a separately prepared battery positive electrode terminal. Then, a battery cover 38 is fixed to the upper end of the battery can 35 by laser welding. As a result, the battery can 35 was sealed, and the same thermopolymerizable solution as in Example 1 was injected under reduced pressure at an absolute pressure of 11 cmHg into the battery can 35 from an electrolyte solution injection port 39 formed in the battery lid 38 in advance. afterwards,
The battery was stored under a temperature environment of 70 ° C. for 10 hours to gel the electrolytic solution in the battery can. With the above configuration, external dimensions 48 mm x 34 m
An mx 8 mm square solid electrolyte battery 30 was produced.

Example 3 (see FIG. 4) The battery members laminated in the same manner as in Example 2 were inserted into a heatable reduced pressure injection box, and the same thermopolymerizable solution as in Example 1 was applied at an absolute pressure of 11 cmHg. Was injected under reduced pressure. Thereafter, the inside of the box was stored under a temperature environment of 70 ° C. for 10 hours, and the internal electrolyte was gelled to obtain a solid electrolyte battery member.
The solid electrolyte battery member was externally opened to a wide-mouthed surface and nickel-plated with external dimensions of 48 mm × 34 mm × 8 mm.
(58mm × 44mm × 8mm including flange 41a)
The positive electrode lead is ultrasonically bonded to the battery case 41, the negative electrode lead is ultrasonically bonded to the wide-mouth lid 42, and the four sides are heat-sealed and sealed with a polyolefin film 43 to form a square solid. An electrolyte battery was manufactured.

COMPARATIVE EXAMPLE 1 LiPF ₆ having a concentration of 2.0 M was prepared by dissolving LiPF _{6 in} a mixture of propylene carbonate / ethylene carbonate / dimethyl carbonate (2/5/3: volume ratio) as a thermopolymerizable solution in Example 1. ₆ solution and the electrolyte 61.444 parts is, as a monofunctional monomer, ethyl glycol methacrylate (molecular weight 188) and 38 parts of a polyfunctional monomer, PO-modified trimethylolpropane triacrylate (molecular weight 470) 0. Example 1 except that 5 parts and 0.056 part of di-myristyl peroxydicarbonate as a thermal polymerization initiator were mixed and dissolved (the ratio of the electrolytic solution to the monomer was 160%). Similarly, a cylindrical solid electrolyte battery was manufactured.

Comparative Example 2 A cylindrical solid electrolyte battery was prepared in the same manner as in Example 1 except that the gelling condition (heating condition) of the electrolyte in Example 1 was 30 ° C. and the heating time was 35 hours. Produced.

Comparative Example 3 A cylindrical solid electrolyte battery was prepared in the same manner as in Example 1 except that the gelling condition (heating condition) of the electrolyte in Example 1 was changed to a heating temperature of 130 ° C. and a heating time of 10 minutes. Produced.

Comparative Example 4 (see FIGS. 1 and 2) The thickness of the separator 3 of Example 1 was changed to 50 μm and 3
A 3 mm (POE) ₉ LiF ₃ CSO ₃ solid electrolyte 5 was prepared, and the strip-shaped positive electrode 1, the strip-shaped negative electrode 2 and the solid electrolyte 5 obtained in the same manner as in Example 1 were replaced with the negative electrode 2, the solid electrolyte 5, and the positive electrode. 1, the solid electrolyte 5 was laminated in this order, and the laminated body was spirally wound many times as shown in FIG. Adhesive tape 4 at end of outermost winding (same as in Example 1)
To produce a spiral electrode having an outer diameter of 19.6 mm.

The (POE) ₉ LiF ₃ CSO ₃
Represents one compound, and the solid electrolyte 5 is formed by molding this compound into a film. In addition, "PO
"E" indicates polyethylene oxide.

The spiral electrode was housed in a nickel-plated iron battery can 15 as shown in FIG. Insulating plates 16a and 16b are provided on the upper and lower surfaces of the spiral electrode, an aluminum positive electrode lead 17 is led out of the positive electrode current collector and welded to the battery cover 18, and a nickel negative electrode lead 19 is drawn out of the negative electrode current collector. And welded to the battery can 15. By caulking the battery can 15 via an insulating sealing gasket 21 coated with asphalt on the surface, the safety valve device 22 having a current interrupting mechanism and the battery lid 18 were fixed to maintain the airtightness in the battery. 20m in diameter with the above configuration
m, a cylindrical solid electrolyte battery 20 having a height of 50 mm was produced.

Comparative Example 5 A cylindrical solid electrolyte battery having the same appearance as that of Example 2 (see FIG. 3) was produced. First, the positive electrode coated on both sides in the same manner as in Example 2 was punched into an outer dimension of 40 mm × 31 mm to obtain a positive electrode member. This positive electrode member is immersed in the following photopolymerizable solution, and the positive electrode member is irradiated with ultraviolet light of a high-pressure mercury lamp with both sides sandwiched by a wire bar while pulling up the positive electrode member from the photopolymerizable solution to form a positive electrode having a gelled solid electrolyte. 16 sheets were prepared.

The above photopolymerizable solution is composed of propylene carbonate / dimethyl carbonate (1
(86 parts) of a 2.0 M concentration LiBF ₄ solution in which LiBF ₄ was dissolved in a mixture of (/ 3: volume ratio) and poly (1-vinyl-1,2-propanediol) as a prepolymer. It was obtained by mixing and dissolving 14 parts of click carbonate and 0.056 parts of benzoin isopropyl ether as a photopolymerization initiator.

On the other hand, the negative electrode coated in the same manner as in Example 2 was punched into an outer size of 42 mm × 32 mm, and gelled in the same procedure as above without bagging in a 25 μm-thick polypropylene pore filter. Seventeen negative electrodes having a gelled solid electrolyte were prepared. While taking care not to entrap the atmospheric gas, these positive and negative electrodes,
The negative electrode is alternately laminated so that the negative electrode is located on the outermost surface.
The laminate was sandwiched on both sides of a 1 mm stainless steel plate and bundled with tape to form a laminate battery member. This laminated battery member is formed of nickel-plated outer dimensions of 48 mm × 34.
It was stored in an iron square battery can of 8 mm × 8 mm. An aluminum positive electrode lead pre-welded to the positive electrode current collector was led out of the positive electrode current collector, and was welded to a separately prepared battery positive electrode terminal. Then, the battery lid was fixed by laser welding to seal the battery can. 48mm × 34mm ×
An 8 mm square solid electrolyte battery was produced.

Comparative Example 6 In Example 1, methoxypolyethylene glycol methacrylate (molecular weight: 111) was used as the monofunctional monomer.
Example 2 was the same as Example 1 except that 2) and polyethylene glycol dimethacrylate (molecular weight 1166) was used as the polyfunctional monomer.

Examples 1 to 3 and Comparative Examples 1 to 6
About the characteristics of the battery manufactured by Toyo System TOSC
The test was performed using an AT3000U charge / discharge measurement device. The results are summarized in [Table 1].

[0062]

[Table 1] * -1) Ah capacity is a measured value at the time of (1/3) C discharge. * -2) The measurement of the cycle characteristics was completed when the capacity reached 80% of the initial capacity. * -3) The Ah capacity is 920 × 0.85 = 782 (mAh / cell).

[0063]

As apparent from the above description, the following effects can be obtained according to the present invention. (1) Claim 1 After inserting a wound or laminated battery member, in which a negative electrode and a positive electrode using lithium or a compound storing lithium are combined via a separator, into a hard case, thermal polymerization is started. Since the non-aqueous electrolyte containing the agent and the polymerizable compound is permeated into the battery case by vacuum injection, and the non-aqueous electrolyte is heated to form an electrolyte layer,
Only by solidifying the electrolyte layer by thermal polymerization, it became possible to mass-produce a solid electrolyte secondary battery with a fast tact and a low production cost, only when the operation of liquid injection under reduced pressure was simplified. In addition, it was possible to solve the difficulty of handling sticky electrodes in mass production runs. As a result, the existing mass production line can be easily diverted, and the battery cost can be greatly reduced.

(2) Claim 2 The battery case is a prismatic battery case, the battery member is inserted into the prismatic battery case, and the prismatic battery case is sealed with a battery cover having an electrolyte solution inlet previously opened. After that, the non-aqueous electrolyte is injected under reduced pressure into the prismatic battery case through the electrolyte injection port, so that the decompression operation can be performed reliably, and the non-aqueous electrolyte Liquid adhesion is prevented, and the yield is improved.

(3) Claim 3 The content of the non-aqueous electrolyte is 200% by weight or more, preferably 20% by weight, based on the polymerizable compound having a thermally polymerizable functional group.
0 to 300% by weight, more preferably 300 to 1000%
By setting the weight%, it is possible to manufacture a solid electrolyte secondary battery having a conductivity substantially the same as that of the electrolytic solution while being a solid electrolyte.

(4) A wound or laminated battery member in which a negative electrode using lithium or a compound that absorbs lithium and a positive electrode are combined via a separator is inserted into a hard case, By penetrating a non-aqueous electrolyte containing a (meth) acrylate monomer and / or a prepolymer thereof as a polymerizable compound into the battery and heating the battery member, the problem of the interface when the positive electrode and the negative electrode are bonded to each other is eliminated, In addition, the difficulty in handling sticky electrodes in a mass production line was solved. For this reason, the impedance became low, the capacity deterioration was reduced even in the discharge at a high current density, and the cycle characteristics were improved. In addition, the existing mass production line can be easily diverted, so that the battery cost can be significantly reduced.

(5) Claim 5 The (meth) acrylate monomer and / or prepolymer thereof has a molecular weight of 1000 or less, preferably 50 or less.
By using a material having a molecular weight of 0 or less, more preferably 300 or less, the nonaqueous solvent in the polymer gel electrolyte can be handled as a stable gel electrolyte without exuding.

(6) Claim 6 Since the electrolyte layer is formed of an ion-conductive polymer gel electrolyte of a crosslinked polymer matrix, the effect of preventing the non-aqueous solvent in the polymer gel electrolyte from oozing out is further enhanced and more stable. It can be handled as a gelled electrolyte.

(7) Claim 7 Since a peroxydicarbonate compound is used as a thermal polymerization initiator, a solid electrolyte secondary battery having excellent potential stability and improved cycle characteristics can be obtained.

(8) Since the heating temperature during the thermal polymerization is in the range of 40 to 120 ° C., the solid electrolyte has higher stability, lower internal impedance, and does not seep out from the gel electrolyte. A secondary battery can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating a method for manufacturing a spiral electrode according to Example 1 of the present invention.

FIG. 2 is a longitudinal sectional view showing the structure of the solid electrolyte secondary battery manufactured in Example 1.

FIG. 3 is a schematic vertical sectional view showing a structure of a solid electrolyte secondary battery manufactured in Example 2.

FIG. 4 is a schematic perspective view showing a rectangular battery case and a procedure for inserting a solid electrolyte battery member into the case, according to the battery manufacturing method of Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Strip positive electrode 2 Strip negative electrode 3 Separator 4 Adhesive tape 5 Solid electrolyte 10 Spiral electrode 15, 35 Battery can 16a, 16b Insulating plate 17, 37 Positive lead 18, 38 Battery lid 19 Negative lead 20 Cylindrical solid electrolyte battery 21 Sealing gasket Reference Signs List 22 Safety valve device 30 Square solid electrolyte battery 31 Positive electrode 32 Negative electrode 33 Separator 34 Plate made of stainless steel 36 Tape 39 Electrolyte injection port 41 Battery case 41a Flange 42 Wide-open lid 43 Film

Claims (8)

[Claims] 1. After inserting a wound or laminated battery member in which a negative electrode and a positive electrode using lithium or a compound that absorbs lithium are combined via a separator into a hard case, a thermal polymerization initiator is provided. And a non-aqueous electrolyte solution containing a polymerizable compound is penetrated into the battery case by vacuum injection, and an electrolyte layer is formed by heating the non-aqueous electrolyte solution to form an electrolyte layer. Production method. 2. The battery case according to claim 1, wherein the battery case is a prismatic battery case, the battery member is inserted into the prismatic battery case, and the prismatic battery case is sealed with a battery lid having an electrolyte injection port previously opened. The method for producing a solid electrolyte secondary battery, wherein the non-aqueous electrolyte is injected under reduced pressure into the prismatic battery case through the electrolyte injection port after stopping. 3. The method according to claim 1, wherein the weight of the non-aqueous electrolyte is at least twice the weight of the polymerizable compound. 4. The method according to claim 1, wherein the polymerizable compound is a (meth) acrylate monomer and / or a prepolymer thereof. 5. The method for producing a solid electrolyte secondary battery according to claim 4, wherein the (meth) acrylate monomer and / or a prepolymer thereof have a molecular weight of 1,000 or less. 6. The method for manufacturing a solid electrolyte secondary battery according to claim 1, wherein the electrolyte layer is formed of an ion-conductive polymer gel electrolyte of a crosslinked polymer matrix. Method. 7. The method for manufacturing a solid electrolyte secondary battery according to claim 1, wherein a peroxydicarbonate compound is used as the thermal polymerization initiator. 8. The method for manufacturing a solid electrolyte secondary battery according to claim 1, wherein the heat treatment is performed within a temperature range of 40 to 120 ° C.