JPH10214639A - Manufacture of battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a battery in which a contact resistance of the boundary face between a separator containing solid electrolyte and electrode layers is reduced, and discharge performance is enhanced. SOLUTION: A battery is equipped with one side electrode which has such a structure as one side electrode layer 2 containing an active material is supported by at least the one side face of a collector 1, and the other side electrode which has such a structure as the other side electrode layer 4 containing the active material is supported by at least the one side face of a collector 3, and a separator sheet 5 which is arranged between one side electrode layer 2 and the other side electrode layer 4 and contains binder and electrolyte. In the manufacturing method thereof, at least the one side electrode layer 2 is manufactured by such a method as possessing a process applying liquid electrode material to the one side of the separator sheet 5 containing at least the binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a battery.

[0002]

2. Description of the Related Art In recent years, with the development of electronic equipment, there has been a demand for the development of a secondary battery that is small, lightweight, has a high energy density, and can be repeatedly charged and discharged. As such a secondary battery, a negative electrode using lithium or a lithium alloy as an active material, and a suspension containing an oxide, sulfide, or selenide as an active material, such as molybdenum, vanadium, titanium, or niobium, were applied. A non-aqueous electrolyte secondary battery including a positive electrode made of a current collector and a non-aqueous electrolyte is known.

In addition, a current collector coated with a suspension containing a carbonaceous material that absorbs and releases lithium ions, such as coke, graphite, carbon fiber, fired resin, and pyrolytic gas phase carbon, is coated on the negative electrode. A non-aqueous electrolyte secondary battery used has been proposed. In the secondary battery, the deterioration of the negative electrode characteristics due to dendrite deposition can be improved, so that the battery life and safety can be improved.

A polymer electrolyte secondary battery, which is an example of a non-aqueous electrolyte secondary battery, is manufactured by, for example, a method described below. First, DBP (dibutyl phthalate)
And a copolymer of vinylidene fluoride [VdF] and hexafluoropropylene [HFP] in the presence of a solvent. A separator sheet not impregnated with an electrolyte is prepared. On the other hand, the active material, the plasticizer, and VdF
The HFP copolymer is mixed in the presence of a solvent, the mixture is formed into a sheet, and the obtained sheet is laminated on a current collector to produce a non-aqueous electrolyte-unimpregnated positive electrode. Further, the plasticizer, the VdF-HFP copolymer, and a carbonaceous material capable of inserting and extracting lithium ions are mixed in the presence of a solvent, formed into a sheet, and the obtained sheet is collected. A negative electrode not impregnated with a non-aqueous electrolyte is prepared by laminating on a conductor. A separator sheet is interposed between the obtained positive electrode and negative electrode, and these are integrated by, for example, thermocompression bonding. Subsequently, after removing the plasticizer in the laminate by, for example, solvent extraction, the secondary battery is manufactured by impregnating with a non-aqueous electrolyte.

However, according to such a manufacturing method, since the positive electrode, the separator sheet, and the negative electrode are integrated by thermocompression bonding, it is difficult to completely adhere the positive electrode and the negative electrode to the separator sheet, and the positive electrode layer surface and the negative electrode There are places on the layer surface that are not in contact with the separator sheet. As a result, the contact resistance at the interface between the separator sheet and the electrode layer is increased, and the impedance of the battery is increased. Therefore, there is a problem that the utilization rate is reduced and the charge / discharge cycle life is shortened.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a battery in which the contact resistance at the interface between the separator sheet containing the electrolyte and the electrode layer is reduced and the discharge performance is improved.

[0007]

According to a method of manufacturing a battery according to the present invention, one electrode having a structure in which one electrode layer containing an active material is supported on at least one surface of a current collector, and the other electrode containing an active material are provided. A method for producing a battery comprising: a second electrode having a structure in which a layer is supported on at least one surface of a current collector; and a separator sheet including a binder and an electrolyte disposed between the one electrode layer and the other electrode layer. The at least one electrode layer is manufactured by a method including a step of applying a liquid electrode material to one surface of a separator sheet containing at least a binder.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing a battery according to the present invention will be described in detail using a polymer electrolyte secondary battery as an example. (1) A method of manufacturing a secondary battery including a power generating element having a structure in which a positive electrode, a separator sheet, and a negative electrode are stacked in this order.

A liquid positive electrode material is applied to one surface of a separator sheet containing a binder and not impregnated with an electrolytic solution, and dried. A current collector is thermocompression-bonded to the obtained electrolyte solution-impregnated positive electrode layer to produce an electrolyte-unimpregnated positive electrode. On the other hand, a liquid-state negative electrode material is applied to the other surface of the separator sheet, dried, and a current collector is thermocompressed to the obtained electrolyte-non-impregnated negative electrode layer to produce an electrolyte-non-impregnated negative electrode. . When a plasticizer is contained in the obtained laminate, the plasticizer is replaced with an alcohol (for example, methanol).
Extract with an organic solvent such as and remove. Next, a positive electrode having a structure in which a positive electrode layer containing an active material and a solid electrolyte is supported on one surface of a current collector by impregnating the laminate with a nonaqueous electrolyte, and a negative electrode layer containing an active material and a solid electrolyte are collected. A polymer electrolyte secondary battery in which a negative electrode having a structure supported on one surface of a body and a separator sheet containing a binder and a solid electrolyte are stacked as shown in FIG. 1 is manufactured.

That is, the positive electrode has a structure in which the positive electrode layer 2 is laminated on the current collector 1. The negative electrode has a structure in which a negative electrode layer 4 is laminated on a current collector 3, and the negative electrode layer 4 is arranged to face the positive electrode layer 2 of the positive electrode. The separator sheet 5
It is interposed between the positive electrode layer 2 and the negative electrode layer 4.

Hereinafter, the separator sheet not impregnated with the non-aqueous electrolyte, the liquid cathode material, the cathode current collector, the liquid anode material, the anode current collector, and the non-aqueous electrolyte will be described. (Separator Sheet Containing Binder and Not Impregnated with Nonaqueous Electrolyte) This separator sheet contains a polymer which serves both as a binder for holding the nonaqueous electrolyte and as a binder.

Examples of the polymer which functions as a binder for holding the non-aqueous electrolyte and as a binder include a polyethylene oxide derivative, a polypropylene oxide derivative, a polymer containing the derivative, polyvinylidene fluoride (PVdF),
A copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP) or the like can be used. The copolymerization ratio of the HFP depends on the method of synthesizing the copolymer, but is usually at most about 20% by weight.

The separator sheet may contain an inorganic filler such as SiO ₂ powder from the viewpoint of improving the compressive strength. The separator sheet can be produced, for example, by the methods (a) to (c) described below.

(A) The above polymer, the above inorganic filler, and a plasticizer are mixed in an organic solvent such as acetone, and a paste is prepared and formed into a film. The separator contains a binder and is not impregnated with an electrolytic solution. Make a sheet.

(B) The polymer is dissolved in an organic solvent such as acetone to prepare a paste, and the obtained paste is applied or filled in a duragard or nonwoven fabric and dried to obtain a separator not impregnated with the electrolyte. Make a sheet.

(C) The above polymer is dissolved in an organic solvent such as acetone to prepare a paste and form a film. The obtained sheet is pressure-bonded to Duragard or a non-woven fabric to produce the electrolyte-unimpregnated separator sheet.

As the plasticizer, dibutyl phthalate (DBP), dioctyl adipate (DOA), D
OP or the like can be used. By adding the plasticizer, flexibility can be imparted to the separator sheet, so that handleability during production can be improved, and the amount of the nonaqueous electrolyte impregnated can be increased.

(Liquid Positive Electrode Material) As the positive electrode material, for example, a paste obtained by mixing an active material, a polymer holding a non-aqueous electrolyte and a conductive material in an organic solvent such as acetone is used. it can.

As the active material, various oxides (for example, lithium manganese composite oxide such as LiMn ₂ O ₄ ,
Manganese dioxide, for example, a lithium-containing nickel oxide such as LiNiO ₂ , for example, a lithium-containing cobalt oxide such as LiCoO ₂ , a lithium-containing nickel cobalt oxide, and an amorphous vanadium pentoxide containing lithium.
And chalcogen compounds (for example, titanium disulfide, molybdenum disulfide, and the like). As the active material, one or two selected from the types described above are used.
More than one species can be used. Among them, it is preferable to use a lithium manganese composite oxide, a lithium-containing cobalt oxide, and a lithium-containing nickel oxide.

Examples of the polymer holding the nonaqueous electrolyte include a polyethylene oxide derivative, a polypropylene oxide derivative, a polymer containing the derivative,
Polyvinylidene fluoride (PVdF), vinylidene fluoride (VdF) and hexafluoropropylene (HF)
A copolymer with P) can be used.

Examples of the conductive material include artificial graphite, carbon black (eg, acetylene black), nickel powder, and the like. A plasticizer such as dibutyl phthalate (DBP) may be added to the positive electrode material from the viewpoint of improving the amount of nonaqueous electrolyte impregnation.

(Positive electrode current collector) The positive electrode current collector includes:
For example, an aluminum mesh current collector such as aluminum expanded metal, aluminum mesh, and aluminum punched metal, or an aluminum plate current collector such as aluminum foil can be used.

(Liquid negative electrode material) As the negative electrode material, a paste obtained by mixing an active material and a polymer holding a nonaqueous electrolyte in an organic solvent such as acetone can be used.

Examples of the active material include carbonaceous materials that occlude and release lithium ions. Such carbonaceous materials include, for example, those obtained by firing organic polymer compounds (eg, phenolic resin, polyacrylonitrile, cellulose, etc.), those obtained by firing coke and pitch, artificial graphite, Examples include carbonaceous materials represented by natural graphite and the like. Above all, in an atmosphere of an inert gas such as an argon gas or a nitrogen gas, 500 ° C. to 30 ° C.
It is preferable to use a carbonaceous material obtained by firing the organic polymer compound at a temperature of 00 ° C. under normal pressure or reduced pressure.

As the polymer for holding the non-aqueous electrolyte, the same polymer as that described for the positive electrode is used. A plasticizer such as dibutyl phthalate (DBP) may be added to the negative electrode material from the viewpoint of improving the impregnation amount of the non-aqueous electrolyte.

Further, the negative electrode material contains conductive material such as artificial graphite, natural graphite, carbon black, acetylene black, Ketjen black, nickel powder, polyphenylene derivative, and filler such as olefin polymer and carbon fiber. Allow.

(Negative electrode current collector) As the negative electrode current collector,
For example, a copper net current collector such as a copper expanded metal, a copper mesh, a copper punched metal, or a copper plate current collector such as a copper foil can be used.

(Non-Aqueous Electrolyte) The non-aqueous electrolyte is prepared by dissolving an electrolyte in a non-aqueous solvent. Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (B
C), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EM
C), γ-butyrolactone (γ-BL), sulfolane,
Acetonitrile, 1,2-dimethoxyethane, 1,3-
Examples thereof include dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), and 2-methyltetrahydrofuran. The non-aqueous solvents may be used alone or as a mixture of two or more.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (L
iPF ₆ ), lithium borotetrafluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide [LiN
(CF ₃ SO ₃ ) ₂ ].

The amount of the electrolyte dissolved in the non-aqueous solvent is desirably 0.2 mol / l to 2 mol / l. (2) A method for manufacturing a secondary battery including a power generating element having a structure in which a positive electrode, a separator sheet, and a negative electrode are stacked in this order.

The above-mentioned liquid cathode material is applied to one surface of the separator sheet not impregnated with the non-aqueous electrolyte, and dried. A net-shaped current collector is placed on the obtained electrolyte-unimpregnated positive electrode layer, and a liquid-state positive electrode material is applied thereon and dried to produce an electrolyte-unimpregnated positive electrode. On the other hand, the above-mentioned liquid negative electrode material is applied to the other surface of the separator sheet and dried. A net-shaped current collector is placed on the obtained electrolyte-impregnated negative electrode layer, and a liquid-state negative electrode material is applied thereon and dried to produce an electrolyte-unimpregnated negative electrode. If the obtained laminate contains a plasticizer, the plasticizer is extracted and removed with an organic solvent such as methanol. Next, a positive electrode having a structure in which a positive electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector by impregnating the laminate with the nonaqueous electrolyte, and a negative electrode layer containing an active material and a solid electrolyte are collected. A polymer electrolyte secondary battery in which a negative electrode having a structure supported on both surfaces of an electric conductor and a separator sheet containing a binder and a solid electrolyte are stacked as shown in FIG. 2 is manufactured.

That is, the secondary battery includes a negative electrode having a structure in which a negative electrode layer 12 is supported on both surfaces of a net-like current collector 11. The positive electrode has a structure in which a positive electrode layer 14 is supported on both surfaces of a mesh current collector 13. A separator sheet 15 is disposed between the negative electrode and the positive electrode.

(3) A method of manufacturing a secondary battery including a power generating element having a structure in which a positive electrode, a separator sheet, and a negative electrode are laminated in this order (partially using a crimping method). The liquid cathode material described above is applied to one surface of the non-aqueous electrolyte-unimpregnated separator sheet and dried. A net-like current collector and a sheet-like positive electrode layer not impregnated with the electrolytic solution are placed on the obtained positive electrode layer not impregnated with the electrolytic solution, and adhered by thermocompression bonding to produce a positive electrode impregnated with no electrolytic solution. Further, the above-mentioned liquid negative electrode material is applied to the other surface of the separator sheet and dried. A net-like current collector and a sheet-like negative electrode layer not impregnated with the electrolyte are placed on the obtained negative electrode layer not impregnated with the electrolytic solution, and adhered by thermocompression bonding to produce a negative electrode impregnated with no electrolytic solution. If the obtained laminate contains a plasticizer, the plasticizer is extracted and removed with an organic solvent such as methanol. Next, a positive electrode having a structure in which a positive electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector by impregnating the laminate with the nonaqueous electrolyte, and a negative electrode layer containing an active material and a solid electrolyte are collected. A polymer electrolyte secondary battery in which a negative electrode having a structure supported on both surfaces of an electric conductor and a separator sheet containing a binder and a solid electrolyte are stacked as shown in FIG. 2 described above is manufactured.

The sheet-shaped positive electrode layer (negative electrode layer) not impregnated with the electrolyte is formed by forming the above-mentioned liquid positive electrode material (negative electrode material) into a film. (4) A method for manufacturing a secondary battery including a power generating element having a structure in which a positive electrode, a separator sheet, a negative electrode, a separator sheet, and a positive electrode are stacked in this order.

The above-described liquid cathode material is applied to one surface of the non-aqueous electrolyte-unimpregnated separator sheet, and dried. A net-like current collector and a positive electrode layer not impregnated with the electrolyte are laminated on the obtained positive electrode layer not impregnated with the electrolytic solution by the coating method or the press-bonding method described above to produce a positive electrode not impregnated with the electrolytic solution.
On the other hand, the above-mentioned liquid negative electrode material is applied to the other surface of the separator sheet and dried. Two three-layer laminates obtained in this manner are prepared, arranged so that the negative electrode layer and the negative electrode layer face each other, and a net-like current collector is disposed between the negative electrode layers. These are bonded by thermocompression bonding. If the obtained laminate contains a plasticizer, the plasticizer is extracted and removed with an organic solvent such as methanol. Next, by impregnating the laminate with the non-aqueous electrolyte, a positive electrode having a structure in which a positive electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector, a separator sheet containing a binder and a solid electrolyte, A polymer electrolyte secondary battery in which a negative electrode having a structure in which a negative electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector, the separator sheet, and the positive electrode are stacked in this order is manufactured.

(5) A method for manufacturing a secondary battery including a power generating element having a structure in which a positive electrode, a separator sheet, a negative electrode, a separator sheet and a positive electrode are laminated in this order. (4) mentioned above
The positive electrode not impregnated with the electrolyte by the same method as described in
3 in which the separator sheet and the negative electrode layer were laminated in this order.
Make a layer stack. Further, the above-mentioned liquid cathode material is applied to one surface of another non-aqueous electrolyte-unimpregnated separator sheet and dried. A net-like current collector and a positive electrode layer not impregnated with the electrolyte are laminated on the obtained positive electrode layer not impregnated with the electrolytic solution by the coating method or the press-bonding method described above to produce a positive electrode not impregnated with the electrolytic solution. The above-mentioned liquid negative electrode material is applied to the other surface of the separator sheet, and a net-like current collector is placed thereon. The three-layer laminate is placed on the current collector such that the negative electrode layer thereof is in contact with the current collector, whereby the negative electrode layers are bonded to each other. When a plasticizer is contained in the obtained laminate, the plasticizer is extracted with an organic solvent such as methanol and removed. Next, by impregnating the laminate with the non-aqueous electrolyte, a positive electrode having a structure in which a positive electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector, a separator sheet containing a binder and a solid electrolyte, A polymer electrolyte secondary battery in which a negative electrode having a structure in which a negative electrode layer containing an active material and a solid electrolyte is supported on both surfaces of a current collector, the separator sheet, and the positive electrode are stacked in this order is manufactured.

In the production methods (1) to (5), both electrode layers containing a binder and being adhered to a separator sheet not impregnated with a non-aqueous electrolyte are prepared by a coating method. Either one may be manufactured by a crimping method.

As described above, the method for manufacturing a battery according to the present invention comprises a method of forming one electrode having a structure in which one electrode layer containing an active material is supported on at least one surface of a current collector, and another electrode layer containing the active material. A battery comprising: a second electrode having a structure supported on at least one surface of a current collector; and a separator sheet disposed between the one electrode layer and the other electrode layer and containing a binder and an electrolyte. The at least one electrode layer is manufactured by a method including a step of applying a liquid electrode material to one surface of a separator sheet containing at least a binder. According to such a method, since at least one electrode layer can be brought into close contact with the separator sheet, the contact resistance at the interface between the electrode layer and the separator sheet can be significantly reduced, and the impedance of the battery is reduced. be able to. as a result,
The discharge performance of the battery can be improved.

In particular, the positive electrode having the structure in which the positive electrode layer containing the active material is supported on at least one side of the current collector and the negative electrode layer containing the active material is formed on at least one side of the current collector according to the production method of the present invention. When applied to a polymer electrolyte secondary battery including a negative electrode having a structure supported by, and a separator sheet including a binder and a lithium ion conductive solid electrolyte disposed between the positive electrode layer and the negative electrode layer, Since at least one of the positive electrode layer and the negative electrode layer can be in close contact with the separator sheet, the contact resistance at the interface between the separator sheet and the electrode layer can be reduced, and the impedance of the secondary battery can be reduced. Can be. Therefore, since the utilization rate of the secondary battery can be improved, the charge / discharge cycle life can be improved.

[0040]

Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1 <Preparation of Separator Sheet Containing Binder and Not Impregnated with Nonaqueous Electrolyte> 22.2% by weight of vinylidene fluoride-hexafluoropropylene (VdF-HFP) copolymer powder and SiO ₂ 33.3% by weight of powder and 44.5% by weight of dibutyl phthalate (DBP) are mixed in acetone,
Paste. The obtained paste is applied on a polyethylene terephthalate film (PET film) having been subjected to a squeezing treatment (silicon etc.) so as to have a thickness of 100 μm, formed into a sheet, and a separator sheet not impregnated with a nonaqueous electrolyte is prepared. did.

<Preparation of Liquid Positive Electrode Material> As an active material, 56% by weight of a lithium manganese composite oxide represented by a composition formula of LiMn ₂ O ₄ , 5% by weight of carbon black, and vinylidene fluoride-hexafluoropropylene ( Vd
17% by weight of a copolymer powder of F-HFP) and 22% by weight of dibutyl phthalate (DBP) in acetone,
A positive electrode paste was prepared.

<Preparation of Liquid Negative Electrode Material> Mesophase pitch carbon fiber (58% by weight) as an active material, vinylidene fluoride-hexafluoropropylene (VdF-HF)
17% by weight of the copolymer powder P) and 25% by weight of dibutyl phthalate (DBP) were mixed in acetone to prepare a negative electrode paste.

<Preparation of Nonaqueous Electrolyte> A nonaqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 2: 1 was mixed with LiPF ₆ as an electrolyte at a concentration of 1 mol / mol. 1 to prepare a non-aqueous electrolyte.

The positive electrode paste was applied to one surface of the separator sheet not impregnated with the electrolyte so as to have a thickness of 145 μm, and dried to form a positive electrode layer not impregnated with the electrolyte. A current collector made of expanded metal made of aluminum was placed on the positive electrode layer, the positive electrode paste was applied thereon so as to have a thickness of 145 μm, and dried to form a positive electrode not impregnated with an electrolytic solution. The negative electrode paste was applied to the other surface of the separator sheet so as to have a thickness of 70 μm, and dried to form a negative electrode layer not impregnated with an electrolyte. A current collector made of expanded metal made of copper was placed on the negative electrode layer, the negative electrode paste was applied thereon so as to have a thickness of 70 μm, and dried to form a negative electrode not impregnated with an electrolytic solution. The obtained laminate was immersed in methanol, and the plasticizer in the laminate was extracted with methanol and removed. The laminate is impregnated with the electrolyte by immersing the laminate in the non-aqueous electrolyte of the composition, and the positive electrode layer containing the active material and the lithium ion conductive solid electrolyte is supported on both surfaces of the current collector. A positive electrode having a structure, a negative electrode having a structure in which a negative electrode layer containing an active material and a lithium ion conductive solid electrolyte is supported on both surfaces of a current collector,
It has a structure in which a binder and a separator sheet containing a lithium ion conductive solid electrolyte are laminated as shown in FIG. 2 described above, and has an area of 80 × 60 mm and a theoretical capacity of 11
A 0 mAh polymer electrolyte secondary battery was manufactured.

(Example 2) A positive electrode paste similar to that of Example 1 was applied to one side of an electrolyte-unimpregnated separator sheet obtained in the same manner as in Example 1 so as to have a thickness of 145 µm. After drying, a positive electrode layer not impregnated with the electrolytic solution was formed. Further, the thickness of the separator sheet is 7
A negative electrode paste similar to that of Example 1 was applied so as to have a thickness of 0 μm, and dried to form a negative electrode layer not impregnated with an electrolytic solution. A current collector made of an expanded metal made of aluminum was disposed on the positive electrode layer, and a 145 μm-thick electrolyte-impregnated positive electrode layer obtained by previously depositing the positive electrode paste thereon was disposed thereon. In addition, a current collector made of a copper expanded metal is disposed on the negative electrode layer, and the thickness obtained by previously forming the negative electrode paste on the current collector is 7 μm.
A 0 μm electrolyte-impregnated negative electrode layer was disposed. These were pressed with a hot roll and bonded. The obtained laminate was immersed in methanol, and the plasticizer in the laminate was extracted with methanol and removed. The laminate is impregnated with the electrolyte by immersing the laminate in the non-aqueous electrolyte of the composition, and the positive electrode layer containing the active material and the lithium ion conductive solid electrolyte is supported on both surfaces of the current collector. Positive electrode with
A negative electrode having a structure in which a negative electrode layer containing an active material and a lithium ion conductive solid electrolyte is supported on both surfaces of a current collector, and a separator sheet containing a binder and a lithium ion conductive solid electrolyte are shown in FIG. 2 described above. Having an area of 80 × 60 mm and a theoretical capacity of 110 mAh
Was manufactured.

Comparative Example A positive electrode paste having the same composition as in Example 1 was formed into a film, and a positive electrode layer not impregnated with an electrolyte solution and having a thickness of 145 μm was formed. The positive electrode layer was adhered to both sides of an aluminum expanded metal as a current collector by pressing with a hot roll to prepare a positive electrode not impregnated with an electrolyte. On the other hand, a negative electrode paste having the same composition as in Example 1 was formed, and a negative electrode layer not impregnated with an electrolytic solution having a thickness of 700 μm was formed. The negative electrode layer was adhered to both surfaces of a copper expanded metal as a current collector by pressing with a hot roll to produce a negative electrode not impregnated with an electrolytic solution. An electrolytic solution-unimpregnated separator sheet obtained in the same manner as in Example 1 was interposed between the obtained positive electrode and negative electrode, and these were bonded by pressing them with a hot roll. The obtained laminate was immersed in methanol, and the plasticizer in the laminate was extracted with methanol and removed. The laminate is impregnated with the electrolyte by immersing the laminate in the non-aqueous electrolyte of the composition, and the positive electrode layer containing the active material and the lithium ion conductive solid electrolyte is supported on both surfaces of the current collector. And a negative electrode having a structure in which a negative electrode layer containing an active material and a lithium ion conductive solid electrolyte is supported on both surfaces of a current collector, and a separator sheet containing a binder and a lithium ion conductive solid electrolyte. It has a laminated structure as shown in FIG.
A polymer electrolyte secondary battery of 0 mm and a theoretical capacity of 110 mAh was manufactured.

With respect to the obtained secondary batteries of Examples 1 and 2 and Comparative Example, 4.5 V was applied at a current of 40 mA for 10 hours.
After the battery was charged to 2.8 V, the battery was repeatedly charged and discharged at a current of 55 mA to 2.8 V, and the discharge capacity of each cycle was measured. The number of cycles when the discharge capacity reached 80% of the discharge capacity in the first cycle was measured, and the results are shown in Table 1 below. The utilization rate was calculated from the discharge capacity at the 10th cycle, and the results are shown in Table 1 below.

Table 1 Utilization Cycle number (cycle life) Example 1 95 (%) 330 Example 2 94 (%) 300 Comparative example 90 (%) 100 As is clear from Table 1, at least a binder is included. In the secondary batteries of Examples 1 and 2 obtained by a method including a step of forming a positive electrode layer and a negative electrode layer on a separator sheet by a coating method, a positive electrode layer and a negative electrode layer are formed on the separator sheet by a pressure bonding method. It can be seen that the utilization factor and the cycle life can be improved as compared with the secondary battery of the comparative example.

[0049]

As described above in detail, according to the present invention, it is possible to provide a method for manufacturing a battery in which the contact resistance at the interface between the separator sheet and the electrode layer is reduced and the discharge performance is improved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a part of a power generating element of a polymer electrolyte secondary battery manufactured by a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional view showing a power generating element of a polymer electrolyte secondary battery manufactured by the manufacturing method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode collector, 2 ... Positive electrode layer, 3 ... Negative electrode current collector, 4 ... Negative electrode layer, 5 ... Separator sheet.

Claims (1)

[Claims] An electrode having a structure in which one electrode layer containing an active material is supported on at least one surface of a current collector, and a structure in which another electrode layer containing an active material is supported on at least one surface of a current collector. A method for manufacturing a battery, comprising: a second electrode having a first electrode layer and a separator sheet including a binder and an electrolyte disposed between the one electrode layer and the other electrode layer, wherein at least one electrode layer has at least a binder A method for producing a battery, comprising: a step of applying a liquid electrode material to one surface of a separator sheet containing: