WO2014045586A1 - 薄型電池およびその製造方法 - Google Patents
薄型電池およびその製造方法 Download PDFInfo
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- WO2014045586A1 WO2014045586A1 PCT/JP2013/005545 JP2013005545W WO2014045586A1 WO 2014045586 A1 WO2014045586 A1 WO 2014045586A1 JP 2013005545 W JP2013005545 W JP 2013005545W WO 2014045586 A1 WO2014045586 A1 WO 2014045586A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/02—Details
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/04—Construction or manufacture in general
- H01M10/0436—Small-sized flat cells or batteries for portable equipment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
- H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
- H01M50/117—Inorganic material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
- H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
- H01M50/121—Organic material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
- H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
- H01M50/124—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
- H01M50/126—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure comprising three or more layers
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2220/00—Batteries for particular applications
- H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0085—Immobilising or gelification of electrolyte
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/543—Terminals
- H01M50/547—Terminals characterised by the disposition of the terminals on the cells
- H01M50/55—Terminals characterised by the disposition of the terminals on the cells on the same side of the cell
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/543—Terminals
- H01M50/552—Terminals characterised by their shape
- H01M50/553—Terminals adapted for prismatic, pouch or rectangular cells
- H01M50/557—Plate-shaped terminals
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/543—Terminals
- H01M50/562—Terminals characterised by the material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/543—Terminals
- H01M50/564—Terminals characterised by their manufacturing process
- H01M50/566—Terminals characterised by their manufacturing process by welding, soldering or brazing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to a thin battery including an electrode group and a flexible exterior body that accommodates the electrode group, and the electrode group includes a sheet-like positive electrode, a sheet-like negative electrode, and an electrolyte layer interposed therebetween. .
- a biological information transmission apparatus has been developed that measures and monitors biological information such as body temperature, blood pressure, and pulse, and automatically sends information to a hospital or the like.
- a biological sticking type device that supplies a drug or the like through a living body skin by applying a potential has been developed.
- Such a battery includes an electrode group in which a plate-like positive electrode and a negative electrode are laminated via a separator, and a positive electrode lead connected to the positive electrode and a part of the negative electrode lead connected to the negative electrode are respectively packaged. It has a structure derived from the outside. The exposed portion of each lead is used as a positive terminal and a negative terminal.
- the exterior body is flexible, if the flexibility of the electrode group is not sufficient, the battery performance is significantly reduced if the battery is repeatedly bent.
- the present inventors have found that the battery performance decreases when the battery is bent repeatedly because the contact area between the active material and the electrolyte layer at the interface between the positive electrode or the negative electrode and the electrolyte layer (hereinafter referred to as the electrode interface) decreases. (That is, peeling).
- the breakage of the electrode group that occurs when the battery is repeatedly bent is often caused by peeling between the electrode and the electrolyte layer.
- a device that operates while being in contact with a living body is repeatedly bent along with the biological activity.
- the stress applied to the electrode group by bending increases as the flexibility of the electrode group becomes poor.
- peeling is accelerated
- the electrode and the electrolyte layer are peeled off, the battery performance is remarkably deteriorated.
- an object of this invention is to provide the thin battery excellent in bending resistance by suppressing peeling with an electrode and an electrolyte layer.
- One aspect of the present invention includes an electrode group and a flexible exterior body that houses the electrode group.
- the electrode group includes a sheet-like positive electrode, a sheet-like negative electrode, and the positive electrode and the negative electrode.
- the at least two types of polymers include a first polymer that does not have a cross-linked structure and a second polymer that has a cross-linked structure.
- Another aspect of the present invention includes (i) a step of preparing a sheet-like positive electrode, (ii) a step of preparing a sheet-like negative electrode, and (iii) at least a crosslinked structure by an electrospinning method.
- the present invention relates to a method for manufacturing a thin battery.
- the present invention it is possible to obtain a thin battery excellent in bending resistance, in which performance deterioration hardly occurs even when bending is repeated. Therefore, even when a thin battery is mounted on a device that requires flexibility, the device can be used for a long time.
- FIG. 1 It is sectional drawing of the thin battery which concerns on one Embodiment of this invention. It is a top view of the thin battery. It is sectional drawing of the laminate sheet used for an exterior body. It is a perspective view of an example of a device carrying a thin battery. It is a figure showing an example of the appearance at the time of changing the device. It is a figure showing roughly composition of an example of a system which manufactures a nonwoven fabric sheet concerning the present invention. It is a top view which shows notionally the structure of the principal part (release body) of the electrostatic spinning mechanism with which the same system is provided. It is a figure which shows the discharge curve before and behind performing the bending deformation process of the thin battery which concerns on Example 1.
- FIG. 1 It is sectional drawing of the thin battery which concerns on one Embodiment of this invention. It is a top view of the thin battery. It is sectional drawing of the laminate sheet used for an exterior body. It is a perspective view of an example of a device carrying a thin battery. It is
- FIG. 2 is a cross-sectional photograph of a composite fiber constituting the nonwoven fabric sheet according to Example 1.
- FIG. 2 is a cross-sectional photograph of a nonwoven fabric sheet according to Example 1. It is a figure which shows the discharge curve before and behind performing the bending deformation process of the thin battery which concerns on the comparative example 1.
- FIG. It is a figure which shows the discharge curve before and behind performing the bending deformation process of the thin battery which concerns on the comparative example 2.
- the thin battery of the present invention includes an electrode group and a flexible exterior body that houses the electrode group.
- the exterior body is, for example, a bag-shaped exterior body formed of a flexible sheet.
- the electrode group includes a sheet-like positive electrode, a sheet-like negative electrode, and an electrolyte layer interposed between the positive electrode and the negative electrode.
- the electrolyte layer includes a non-aqueous electrolyte and a non-woven sheet that holds the non-aqueous electrolyte.
- the nonwoven fabric sheet may be in a swollen state with a nonaqueous electrolyte.
- the nonwoven sheet includes a composite fiber in which at least two kinds of polymers are combined.
- the composite fiber does not mean a composite of a first fiber made of a single polymer and a second fiber made of another single polymer.
- the composite fiber means that one fiber is formed of two or more kinds of polymers.
- the composite fiber is, for example, a fiber in which at least two polymer polymer alloys are formed. Therefore, when the cross section of one composite fiber is observed in detail, at least two phases composed of different polymers are observed.
- the at least two kinds of polymers include a first polymer that does not have a crosslinked structure and a second polymer that has a crosslinked structure.
- the composite fiber includes the first polymer that does not have a cross-linked structure, it is possible to form a nonwoven fabric sheet composed of high-quality fibers.
- the composite fiber contains a second polymer having a cross-linked structure, so that it is possible to form a nonwoven fabric sheet having excellent adhesion to the electrode, high nonaqueous electrolyte retention ability, and excellent strength. It becomes.
- 3 or more types may be sufficient as the polymer which comprises a composite fiber.
- the electrolyte layer including the nonwoven fabric sheet as described above is excellent in adhesiveness with the electrode, the active material and the electrolyte layer at the electrode interface even when the battery is repeatedly bent regardless of the flexibility of the electrode group. Reduction of the contact area, that is, peeling hardly occurs.
- the cross-section of the composite fiber preferably has a sea-island structure including a sea component and an island component dispersed in the sea component.
- the second polymer having a crosslinked structure tends to form a sea component
- the first polymer not having a crosslinked structure tends to form an island component.
- the composite fiber having a sea-island structure is homogeneous, it is possible to form a nonwoven fabric sheet composed of higher quality fibers (for example, homogeneous nanofibers having a fiber diameter of 800 nm or less).
- the second polymer having excellent adhesion to the electrode, high ability to hold the nonaqueous electrolyte, and excellent strength is distributed in a network in the electrolyte layer, the electrode, the electrolyte layer, The adhesion and liquid retention are also homogenized.
- the content of the first polymer contained in the composite fiber is preferably 10 to 70% by mass, and more preferably 30 to 50% by mass.
- the fiberization of the composite becomes easier. Therefore, it becomes easier to obtain a uniform nanofiber having a fiber diameter of 800 nm or less.
- the composite fiber may contain three or more kinds of polymers.
- the total of the first polymer and the second polymer is a composite. It is desirable to occupy 50% by mass or more, more preferably 80% by mass or more of the fiber.
- the first polymer is not particularly limited as long as it does not have a crosslinked structure.
- an olefin resin, a fluorine resin, a polyamide resin, a polyimide resin, or the like can be used.
- Such a polymer is also advantageous in that the affinity with the nonaqueous electrolyte can be increased.
- the first polymer is preferably a fluororesin because it is easily fiberized and chemically stable.
- fluororesins examples include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer ( Examples thereof include homopolymers or copolymers having fluorine-containing monomer units such as PFA), tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF).
- PTFE polytetrafluoroethylene
- FEP tetrafluoroethylene-hexafluoropropylene copolymer
- VDF polyvinylidene fluoride
- PVF polyvinyl fluoride
- a polymer having a vinylidene fluoride unit is preferable because of its excellent affinity with a nonaqueous electrolyte.
- the ratio of the vinylidene fluoride unit is, for example, preferably 50 to 100 mol%, and more preferably 65 to 95 mol%.
- the polymer having a vinylidene fluoride unit for example, a copolymer containing a vinylidene fluoride unit and a hexafluoropropylene unit is preferable.
- the ratio of hexafluoropropylene units is preferably 0 to 50 mol%, and more preferably 5 to 35 mol%.
- the weight average molecular weight of the first polymer is not particularly limited, but it is preferably 100,000 to 2,000,000, taking into consideration that the fiber is formed by the electrospinning method, and 150,000 to 1,000. Is more preferable. This is because the first polymer having such a molecular weight is easily dissolved in a solvent and the concentration of the solution can be easily adjusted.
- the second polymer is not particularly limited as long as it is a polymer having a crosslinked structure.
- a polymer containing monomer units such as acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinyl acetate, acrylonitrile, styrene, divinylbenzene, and alkylene oxide is preferable. These monomer units may be used individually by 1 type, and may be used in combination of multiple types.
- the ester groups of the acrylic acid ester and the methacrylic acid ester preferably have a C2 to C10 (preferably C2 to C8) alkyl group, a polyalkylene oxide group, and the like from the viewpoint of improving adhesiveness.
- the second polymer examples include polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyalkylene oxide, modified polystyrene, polyacrylonitrile, polyalkyl acrylate, polyalkyl methacrylate, polyester, and copolymers thereof. Etc. can be used. Among these, at least one selected from the group consisting of an acrylate ester unit and a methacrylic acid ester unit (hereinafter referred to as (meth) acrylate ester) in terms of high adhesiveness and high affinity with an electrode active material. ) And polymers having a polyalkylene oxide structure are preferred.
- the content of the polyalkylene oxide structure is preferably controlled to 20 to 95% by mass. This is because a polymer containing a polyalkylene oxide structure at such a ratio is not only excellent in adhesiveness but also can be made into a fiber relatively easily by complexing with the first polymer.
- the weight average molecular weight of the second polymer is not particularly limited, but it is preferably 300,000 to 6,000,000, and 500,000 to 5,000, considering that the fiber is formed by an electrospinning method. Is more preferable. When the second polymer having such a molecular weight is used, it becomes easy to form a composite fiber having excellent strength.
- the second polymer may be a polymer (for example, a dendrimer) having a core-shell type structure having a core portion and a shell portion.
- a polymer having a core-shell structure forms a sea component of a sea-island structure by forming a cross-linked structure that connects shell portions of adjacent polymers.
- Such a sea component is very excellent in adhesiveness, nonaqueous electrolyte retention ability and strength. Therefore, it becomes easy to obtain a thin battery that is unlikely to deteriorate in performance even when repeated intense bending.
- the shell portion preferably has a structure with excellent viscosity from the viewpoint of expressing sufficient adhesiveness.
- a structure include a segment composed of at least one polymer of acrylic acid ester and methacrylic acid ester, and the ester portion has a polyene structure, a polyalkylene oxide structure, C2 to C10 (preferably C2 A structure having a flexible molecular chain such as an alkyl group of C8) is preferable.
- the core part preferably has a structure with excellent elasticity from the viewpoint of giving strength to the sea component.
- a structure has a segment made of a polymer containing, for example, styrene, acrylonitrile and the like. More specifically, a polystyrene structure, a styrene-butadiene copolymer structure, a styrene-acrylonitrile copolymer structure, and the like are preferable.
- a polymer having a shell portion having a polyalkylene oxide structure (especially a polyethylene oxide group) has high adhesiveness and high affinity with an electrode active material. It is advantageous for improving the adhesion of
- the core part preferably has a polystyrene structure.
- a polystyrene structure By having a polystyrene structure, the elasticity of the core portion becomes good and it becomes easy to form a composite fiber having excellent strength.
- Examples of a method for crosslinking a polymer having a core-shell structure include a method in which a hydroxyl group, an acyl group, or the like is introduced into a side chain or a terminal of a shell portion and a crosslinking agent is added.
- a crosslinked structure is formed by reacting a crosslinking agent having a plurality of functional groups that react with the hydroxyl group (such as isocyanate groups) with a polymer having a core-shell structure.
- the nonwoven fabric sheet is preferably formed directly on the electrode surface by an electrostatic spinning method. More specifically, a nonwoven fabric sheet is formed by generating composite fibers by electrostatic force from a raw material liquid containing the first polymer and the second polymer and depositing the generated composite fibers on the electrode surface. Is preferred.
- the nonwoven fabric sheet formed by directly depositing the composite fibers on the electrode surface is extremely strongly bonded to the electrode surface, for example, by being partially combined with the electrode surface.
- the composite fiber may be formed on the surface of the positive electrode, may be formed on the surface of the negative electrode, or may be formed on the surfaces of both the positive electrode and the negative electrode.
- the thin battery has at least a crosslinked structure by, for example, (i) a step of preparing a sheet-like positive electrode, (ii) a step of preparing a sheet-like negative electrode, and (iii) an electrostatic spinning method.
- the group is preferably produced together with a non-aqueous electrolyte by a production method including a step of housing the group in a flexible exterior body and sealing the exterior body under reduced pressure.
- nanofibers as composite fibers are generated by an electrostatic stretching phenomenon.
- the raw material liquid containing charges is discharged into the nanofiber formation space, and the raw material liquid is stretched by the repulsive force of the Coulomb force of the charges existing in the raw material liquid.
- the repulsive force exceeds the surface tension of the raw material liquid, the raw material liquid is explosively stretched linearly. Since the surface area of the stretched raw material liquid increases dramatically, a large amount of solvent evaporates from the raw material liquid.
- the repulsive force of the Coulomb force of the charges existing in the raw material liquid further increases and the raw material liquid is further stretched.
- a fiber (nanofiber) having a fiber diameter from submicron to nano-order can be efficiently produced.
- the fiber diameter of the produced composite fiber can be controlled by the state of the raw material liquid, the configuration of the emitter that discharges the raw material liquid, the magnitude of the electric field formed in the nanofiber formation space by the charging means, and the like.
- Examples of the solvent contained in the raw material liquid containing the first polymer and the second polymer include acids (organic acids such as acetic acid, inorganic acids such as hydrochloric acid), bases (organic bases such as triethylamine; sodium hydroxide, etc.
- acids organic acids such as acetic acid, inorganic acids such as hydrochloric acid
- bases organic bases such as triethylamine; sodium hydroxide, etc.
- organic solvents such as ketones such as acetone, nitriles such as acetonitrile, amides, ethers such as tetrahydrofuran, sulfoxides such as dimethyl sulfoxide, N-methyl-2-pyrrolidone and the like can be exemplified.
- the fiber diameter of the composite fiber is preferably 50 to 2,000 nm.
- the composite fiber is a nanofiber having such a fiber diameter, the porosity of the nonwoven fabric sheet is increased, and more nonaqueous electrolyte can be retained. Moreover, since the ratio of the active material shielded by the composite fiber is reduced, it is advantageous for improving the charge / discharge characteristics.
- the fiber diameter of the composite fiber is more preferably 60 to 1,500 nm, still more preferably 80 to 1,000 nm. Moreover, it is preferable that the fiber diameter of a composite fiber is 800 nm or less.
- the fiber diameter refers to the maximum diameter when the cross section of the composite fiber is viewed.
- the nonwoven fabric sheet is preferably mainly formed of a composite fiber having a fiber diameter of 50 to 2,000 nm.
- a composite fiber having a fiber diameter of 50 to 2,000 nm For example, when the cross section in the thickness direction of the nonwoven fabric sheet is viewed, in the range of 10 ⁇ m ⁇ 10 ⁇ m, 60% or more of the total area occupied by the composite fiber is occupied by the composite fiber having a fiber diameter of 50 to 2,000 nm. It is preferable.
- the nonwoven fabric sheet may include a composite fiber having a fiber diameter of less than 50 nm and greater than 2,000 nm.
- the thickness of the electrolyte layer may be appropriately selected depending on the thickness of the thin battery.
- the thickness of the electrolyte layer swollen with the nonaqueous electrolyte may be, for example, 5 to 200 ⁇ m.
- the thinner one is desirable, preferably 10 to 100 ⁇ m, and more preferably 15 to 70 ⁇ m.
- the positive electrode includes a positive electrode current collector and a positive electrode mixture layer that adheres to the positive electrode current collector and contacts the electrolyte layer.
- the positive electrode mixture layer includes a positive electrode active material and a binder.
- the negative electrode includes a lithium metal sheet or a lithium alloy sheet (hereinafter, lithium-based active material).
- a negative electrode includes, for example, a negative electrode current collector and a lithium-based active material attached to the negative electrode current collector.
- the adhesive strength with the electrolyte layer is generally likely to be low.
- such a defect is greatly improved by forming the electrolyte layer with the nonwoven fabric sheet containing the composite fiber as described above.
- the outer package is preferably formed of, for example, a laminate sheet including a water vapor barrier layer and resin layers formed on both sides thereof.
- a laminate sheet including a water vapor barrier layer and resin layers formed on both sides thereof.
- Such an outer package can prevent water vapor from entering the inside of the thin battery, so that deterioration of characteristics during storage of the thin battery is suppressed.
- the laminate sheet since the laminate sheet has high flexibility, it is advantageous for obtaining a thin battery having excellent bending resistance.
- the electrode group includes a first current collector and a first current material layer attached to one surface of the first current collector, a second current collector, and A second electrode including a second active material layer attached to one surface thereof, and an electrolyte layer interposed between the first active material layer and the second active material layer are included.
- the other surface of the first current collector and the other surface of the second current collector sheet are in contact with the inner surface of the exterior body.
- the first electrode including the first current collector and the first active material layer may be a positive electrode or a negative electrode.
- the electrode group includes a first current collector and a first active material layer attached to one surface thereof, a pair of first electrodes, a second current collector, and first electrodes attached to both surfaces thereof.
- seat is in contact with the inner surface of an exterior body, respectively.
- the first electrode including the first current collector and the first active material layer may be a positive electrode or a negative electrode.
- FIG. 1 is a schematic cross-sectional view of a thin battery 21.
- FIG. 2 is a top view of the battery 21.
- FIG. 1 corresponds to a cross-sectional view taken along line II-II in FIG.
- the battery 21 includes an electrode group 13 and an exterior body 8 that houses the electrode group 13.
- the electrode group 13 includes a negative electrode 11, a positive electrode 12, and an electrolyte layer 7 interposed between the negative electrode 11 and the positive electrode 12.
- the negative electrode 11 has a negative electrode current collector sheet 1 and a negative electrode active material layer 2 attached to one surface of the negative electrode current collector sheet 1.
- the positive electrode 12 has a positive electrode current collector sheet 4 and a positive electrode active material layer 5 attached to one surface of the positive electrode current collector sheet 4.
- the negative electrode 11 and the positive electrode 12 are disposed so that the positive electrode active material layer 5 and the negative electrode active material layer 2 face each other with the electrolyte layer 7 interposed therebetween.
- a negative electrode lead 3 is connected to the negative electrode current collector sheet 1
- a positive electrode lead 6 is connected to the positive electrode current collector sheet 4.
- a part of the negative electrode lead 3 and the positive electrode lead 6 is exposed to the outside from the exterior body 8, and the exposed portions function as a negative electrode external terminal and a positive electrode external terminal.
- the exterior body 8 is formed of, for example, a laminate sheet including a barrier layer and resin layers respectively formed on both sides thereof.
- the method for forming the laminate sheet on the exterior body is not particularly limited. For example, when the laminate sheet has an area larger than the rectangular area when two electrode groups 13 are arranged along a plane, the laminate sheet is folded at the center line, and the two opposing sides connected by the center line A bag-shaped exterior body is obtained by adhering the peripheral edges of the two. On the other hand, when the laminate sheet is folded back at the center line, both ends of the laminate sheet are overlapped, and then the ends are welded together, a cylindrical exterior body is obtained.
- the negative electrode current collector sheet 1 a metal film, a metal foil or the like is used.
- the negative electrode current collector sheet 1 preferably does not form an alloy with the negative electrode active material and is excellent in electronic conductivity. Therefore, the negative electrode current collector sheet 1 is preferably at least one foil selected from the group consisting of copper, nickel, titanium, alloys thereof, and stainless steel.
- the thickness of the negative electrode current collector sheet 1 is preferably 5 to 30 ⁇ m, for example. By setting the thickness of the negative electrode current collector sheet 1 to 5 ⁇ m or more, the negative electrode current collector sheet 1 can maintain excellent strength. By setting the thickness of the negative electrode current collector sheet 1 to 30 ⁇ m or less, higher flexibility can be imparted to the negative electrode current collector sheet 1, and it is difficult for large stress to be generated in the negative electrode current collector sheet 1 when bent. Become.
- the negative electrode active material layer 2 may be a lithium metal sheet or a lithium alloy sheet (lithium-based active material), a powder negative electrode active material, a binder, and a mixture layer containing a conductive agent as necessary.
- a deposited film formed by such a vapor phase method may be used.
- the negative electrode active material included in the mixture layer include carbon materials (for example, graphite), silicon alloys, and silicon oxides.
- the deposited film include a silicon alloy film and a silicon oxide film.
- the thickness of the negative electrode active material layer is preferably, for example, 1 to 300 ⁇ m, and more preferably 10 to 100 ⁇ m.
- the lithium alloy for example, a Li—Si alloy, a Li—Sn alloy, a Li—Al alloy, a Li—Ga alloy, a Li—Mg alloy, or a Li—In alloy is used.
- the proportion of elements other than Li in the lithium alloy is preferably 0.1 to 10% by weight.
- the positive electrode current collector sheet 4 is made of a metal material such as a metal film, a metal foil, or a metal fiber non-woven fabric.
- the positive electrode current collector sheet is preferably at least one foil selected from the group consisting of, for example, silver, nickel, palladium, gold, platinum, aluminum, alloys thereof, and stainless steel.
- the thickness of the positive electrode current collector sheet is preferably 1 to 30 ⁇ m, for example.
- the positive electrode active material layer 5 may be a mixture layer containing a positive electrode active material, a binder, and, if necessary, a conductive agent, or a deposited film formed by a vapor phase method such as vapor deposition.
- the positive electrode active material is not particularly limited. For example, at least one selected from the group consisting of manganese dioxide, carbon fluoride (fluorinated graphite), lithium-containing composite oxide, metal sulfide, and organic sulfur compound is used. it can.
- the thickness of the positive electrode active material layer is preferably 1 to 300 ⁇ m, for example.
- fluorinated graphite represented by (CF w ) m (wherein m is an integer of 1 or more and 0 ⁇ w ⁇ 1) or manganese dioxide is suitable.
- the positive electrode active material of the secondary battery include lithium-containing composite oxides such as Li xa CoO 2 , Li xa NiO 2 , Li xa MnO 2 , Li xa Co y Ni 1-y O 2 , and Li xa Co y M 1.
- Li xa Ni 1 -y M y O z, such as Li xb Mn 2 O 4, Li xb Mn 2-y M y O 4 is suitable.
- xa and xb are values before the start of charging / discharging, and increase / decrease by charging / discharging.
- Conductive agents included in the positive electrode or negative electrode mixture layer include graphites such as natural graphite and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Used.
- the binder to be included in the positive electrode or negative electrode mixture layer includes polyvinylidene fluoride (PVDF), fluorine resin such as polytetrafluoroethylene, acrylic resin such as polyacrylonitrile and polyacrylic acid, and rubber such as styrene butadiene rubber. And the like are used.
- PVDF polyvinylidene fluoride
- fluorine resin such as polytetrafluoroethylene
- acrylic resin such as polyacrylonitrile and polyacrylic acid
- rubber such as styrene butadiene rubber. And the like are used.
- the nonaqueous electrolyte is, for example, a mixture of a lithium salt and a nonaqueous solvent.
- the lithium salt include LiClO 4 , LiBF 4 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , and imide salts.
- Specific examples of the non-aqueous solvent include, for example, cyclic carbonates such as propylene carbonate, ethylene carbonate, and butylene carbonate; chain carbonate esters such as diethyl carbonate, ethyl methyl carbonate, and dimethyl carbonate; ⁇ -butyrolactone, ⁇ -valero And cyclic carboxylic acid esters such as lactones.
- the negative electrode lead 3 and the positive electrode lead 6 are connected to the negative electrode current collector sheet or the positive electrode current collector sheet, for example, by welding.
- the negative electrode lead for example, a copper lead, a copper alloy lead, a nickel lead or the like is preferably used.
- the positive electrode lead for example, a nickel lead or an aluminum lead is preferably used.
- the laminate sheet 8 includes an inorganic material layer (barrier layer) 8a, a first resin film 8b bonded to one surface of the barrier layer 8a, and a second resin film bonded to the other surface of the barrier layer 8a. 8c.
- the inorganic material used for forming the barrier layer 8a is not particularly limited, but it is preferable to use a metal layer, a ceramic layer, or the like in terms of barrier performance, strength, bending resistance, and the like.
- metal materials such as aluminum, titanium, nickel, iron, platinum, gold, and silver
- inorganic oxide materials such as silicon oxide, magnesium oxide, and aluminum oxide are preferable.
- aluminum oxide and silicon oxide are particularly preferable from the viewpoint of excellent balance between flexibility and barrier properties of the obtained laminate sheet, and aluminum is particularly preferable from the viewpoint of low manufacturing cost.
- the thickness of the barrier layer of the exterior body is desirably as thin as possible from the viewpoint of ensuring the flexibility of the exterior body.
- the thickness is preferably 35 ⁇ m or less, more preferably 20 ⁇ m or less, and even more preferably 0.5 ⁇ m or less.
- 0.01 ⁇ m or more is preferable, 0.05 ⁇ m or more is more preferable, and 0.1 ⁇ m or more is more preferable.
- the resin film material disposed on the inner surface side of the exterior body is a polyolefin such as polyethylene (PE) or polypropylene (PP), polyethylene terephthalate, or polyamide.
- PE polyethylene
- PP polypropylene
- EVA polyethylene-vinyl acetate copolymer
- the thickness of the resin film on the inner surface side is preferably 10 to 100 ⁇ m, more preferably 10 to 50 ⁇ m.
- the resin film placed on the outer surface side of the exterior body is polyamide (PA) such as 6,6-nylon, polyolefin, polyethylene terephthalate (PET), polybutylene terephthalate. Polyesters such as are preferred. From the same viewpoint, the thickness of the resin film on the outer surface side is preferably 5 to 100 ⁇ m, more preferably 10 to 50 ⁇ m.
- the total thickness of the laminate sheet is, for example, 15 to 300 ⁇ m, and preferably 30 to 150 ⁇ m.
- various performances required for the exterior body can be sufficiently secured, and the thickness of the thin battery or the battery package can be easily kept small.
- the thin battery is suitable, for example, for forming a device in a form in which a thin battery and an electronic device are integrated into a sheet.
- Examples of such an electronic device include a biological sticking type device such as a biological information measuring device and an iontophoresis transdermal dosage device.
- the bio-applied device Since the bio-applied device is used in a state of being in close contact with a living body, it is required to have flexibility that does not cause discomfort even if it is in close contact with the skin for a long time. Therefore, excellent flexibility is also required for the power source for driving the bio-applied device. Thin batteries are useful as power sources for such devices.
- FIG. 4 is a perspective view showing an example of a battery-electronic device assembly (battery device) including a biological information measuring device.
- FIG. 5 shows an example of the appearance when the device is deformed.
- the biological information measuring device 22 includes a sheet-like holding member 22a that holds the constituent elements.
- the holding member 22a is made of a flexible material, and the temperature sensor 23, the pressure sensitive element 24, the storage unit 25, the information transmission unit 26, the button switch SW1, and the control unit 27 are embedded in a region from the inside to the surface. It is.
- the thin battery 21 is accommodated in a flat space provided inside the holding member 22a. That is, the battery 21 and the biological information measuring device 22 are integrally formed into a sheet and constitute a battery-electronic device assembly 29.
- an insulating resin material can be used for the holding member 22a.
- an adhesive 28 having adhesive force can be applied to one main surface of the battery-electronic device assembly.
- the biological information measuring device 22 can be wound around the user's wrist, ankle, neck, or the like.
- the temperature sensor 23 is configured using, for example, a thermosensitive element such as a thermistor or a thermocouple, and outputs a signal indicating the user's body temperature to the control unit 27.
- the pressure sensitive element 24 outputs a signal indicating the blood pressure and pulse of the user to the control unit 27.
- a nonvolatile memory can be used as the storage unit 25 that stores information according to the output signal.
- the information transmission unit 26 converts necessary information into a radio wave according to a signal from the control unit 27 and radiates it.
- the switch SW1 is used when the biological information measuring device 22 is switched on and off.
- a positive electrode mixture containing a positive electrode active material, a conductive material and a binder is mixed with a dispersion medium such as N-methyl-2-pyrrolidone (NMP), and a positive electrode mixture paste And is applied to a positive electrode current collector sheet, dried, and rolled.
- NMP N-methyl-2-pyrrolidone
- the negative electrode is obtained by, for example, pressing a lithium metal sheet or a lithium alloy sheet on the negative electrode current collector sheet, and bringing the negative electrode current collector sheet and the lithium metal sheet or lithium alloy sheet into close contact with each other. It is done.
- a non-woven sheet is obtained from a raw material liquid containing a first polymer having no cross-linked structure and a second polymer having a cross-linked structure by an electrospinning method. And a step of generating a composite fiber containing the second polymer, and a step of depositing the generated composite fiber on the electrode surface to form a nonwoven fabric sheet containing the composite fiber.
- the raw material liquid containing the first polymer and the second polymer dissolved in the solvent and the solvent is discharged into the nanofiber formation space.
- the discharged raw material liquid is drawn by an electrostatic drawing phenomenon to become a composite fiber.
- the step of forming the nonwoven fabric sheet is performed at the end point position of the nanofiber formation space (that is, the electrode surface) following the step of generating the composite fiber.
- the composite fiber is deposited on the electrode surface immediately after its formation to form a nonwoven sheet.
- (D) Preparation of electrode group a positive electrode and a negative electrode are laminated
- the electrode group is housed in an exterior body together with a non-aqueous electrolyte, and the exterior body is sealed under reduced pressure to complete a thin battery.
- the opening is closed by thermal welding.
- the electrode group is arranged so that a part of the positive electrode lead and the negative electrode lead is exposed to the outside from one opening of the cylindrical exterior body. This exposed portion becomes a positive external terminal and a negative external terminal.
- the opening is closed by heat welding under reduced pressure. In this way, the electrode group is sealed in the exterior body.
- the nonaqueous electrolyte is impregnated in the voids in the electrode group, mainly the voids in the nonwoven fabric sheet. Thereby, a composite fiber swells with a nonaqueous electrolyte and an electrolyte layer is formed.
- the manufacturing system 100 of FIG. 6 constitutes a manufacturing line for forming a nonwoven fabric sheet by directly depositing composite fibers on the electrode surface.
- the long electrode E is conveyed from the upstream to the downstream of the manufacturing line.
- the manufacturing system 100 is used when a nonwoven fabric sheet is continuously formed on the surface of the long electrode E, but the configuration of the manufacturing system is appropriately changed according to the shape of the electrode.
- the uppermost stream of the manufacturing system 100 is provided with an electrode supply device 30 that houses therein an electrode E wound in a roll shape.
- the electrode supply device 30 rolls out the roll-shaped electrode E and supplies the electrode E to another device adjacent to its own downstream side. Specifically, the electrode supply device 30 rotates the supply reel 32 by the motor 34 and supplies the electrode E wound around the supply reel 32 to the first transport roller 31.
- the unrolled electrode E is transferred to the nonwoven fabric sheet forming apparatus 40 by the first transport roller 31.
- the nonwoven fabric sheet forming apparatus 40 includes an electrostatic spinning mechanism. More specifically, the electrospinning mechanism normally includes an emitter 42 for discharging the raw material liquid installed above the apparatus, a charging means for charging the discharged raw material liquid, a collector unit, It has.
- the transport conveyor 41 that transports the electrode E from the upstream side to the downstream side so as to face the emitter 42 functions together with the electrode E as a collector unit that collects the composite fibers.
- the charging means includes a voltage applying device 43 that applies a voltage to the emitter 42 and a counter electrode 44 that is installed in parallel with the transport conveyor 41 and is electrically connected.
- the counter electrode 44 is grounded. Thereby, a potential difference (for example, 20 to 200 kV) corresponding to the voltage applied by the voltage application device 43 can be provided between the emitter 42 and the counter electrode 44.
- the configuration of the charging unit is not particularly limited.
- the counter electrode 44 may not necessarily be grounded, and a high voltage may be applied.
- the emitter 42 is made of a conductor, has a long shape, and its inside is hollow.
- the hollow portion serves as a storage portion that stores the raw material liquid 45.
- the raw material liquid 45 is supplied from the raw material liquid tank 45 a to the hollow of the emitter 42 by the pressure of the pump 46 communicating with the hollow portion of the emitter 42.
- the raw material liquid 45 is discharged from the plurality of discharge ports toward the surface Ea of the electrode E by the pressure of the pump 46.
- the discharged raw material liquid is electrostatically exploded while moving in the space between the emitter 42 and the transport conveyor 41 in a charged state, and generates a composite fiber.
- the produced composite fiber is attracted to the surface Ea of the electrode E by electrostatic attraction, and is deposited there. Thereby, the nonwoven fabric sheet of the state adhering to the electrode surface is formed.
- FIG. 7 is a top view schematically showing the configuration of the nonwoven fabric sheet forming apparatus 40.
- the emitter 42 is installed so as to be perpendicular to the moving direction of the electrode E (the direction of the white arrow in FIG. 7).
- the emitter 42 has a longitudinal direction extending from the surface Ea of the electrode by a second support 49 extending downward from the first support 48 parallel to the moving direction of the electrode E installed above the nonwoven fabric sheet forming apparatus 40. It is supported to be parallel.
- a plurality of raw material liquid outlets 42a are provided on the side of the emitter 42 facing the surface Ea of the electrode E.
- the discharge ports 42a on the discharge bodies 42 are arranged in a regular pattern, the amount of the composite fiber deposited on the surface Ea of the electrode E can be made uniform over a wide region of the surface Ea.
- the distance between the discharge port 42a of the emitter 42 and the surface Ea of the electrode E may be, for example, 100 to 600 mm, depending on the scale of the manufacturing system.
- the non-woven fabric sheet-electrode assembly carried out from the non-woven fabric sheet forming apparatus 40 is transferred to a drying device 50 arranged further downstream.
- An electrode temperature / humidity adjustment device 51 is installed in the drying device 50.
- the drying apparatus 50 when the active material contained in the vicinity of the surface of the electrode E diffuses to the nonwoven fabric sheet while the nonwoven fabric sheet is dried, the nonwoven fabric sheet and the mixture layer can be partially combined. As a result, a composite layer containing the composite fiber, the active material, and the binder is formed at the interface between the electrolyte layer and the mixture layer. Due to the presence of such a composite layer, the electrolyte layer and the electrode are more firmly bonded.
- the completed nonwoven sheet-electrode assembly S is transported from the drying device 50 to the recovery device 70 and wound around the recovery reel 72 via the second transport roller 71.
- the collection reel 72 is rotationally driven by a motor 74.
- Example 1 A thin battery having a basic structure similar to that of the battery shown in FIGS. (1) Production of Negative Electrode
- As the negative electrode current collector sheet 1 an electrolytic copper foil having a thickness of 12 ⁇ m was prepared.
- a lithium metal sheet (thickness 20 ⁇ m), which is the negative electrode active material layer 2 was pressure bonded to one surface of the electrolytic copper foil with a linear pressure of 100 N / cm to obtain a negative electrode 11. This was cut out to a size of 50 ⁇ 50 mm having a tab portion of 5 mm ⁇ 5 mm at the center of one short side, and then a copper negative electrode lead 3 was ultrasonically welded to the tab portion.
- an aluminum foil (thickness: 15 ⁇ m) was prepared.
- the positive electrode mixture paste is applied to one surface of the aluminum foil, dried at 85 ° C. for 10 minutes to form the positive electrode mixture layer 5, and then compressed with a roll press at a linear pressure of 12000 N / cm.
- a positive electrode 12 was obtained. This was cut out to a size of 50 ⁇ 50 mm having a tab portion of 5 mm ⁇ 5 mm at the center of one short side, and then dried under reduced pressure at 120 ° C. for 2 hours.
- An aluminum positive electrode lead 6 was ultrasonically welded to the tab portion.
- the polymer having a core-shell structure a polymer having a cross-linked structure in which the core portion includes a polystyrene structure, the shell portion includes a polyethylene oxide structure, the content of the polyethylene oxide structure is 40% by mass.
- the shell part of adjacent core shells was connected using the crosslinking agent (tolylene diisocyanate).
- the raw material liquid is discharged from a discharge body of an apparatus having an electrospinning mechanism as shown in FIGS. 6 and 7, a composite fiber containing a first polymer and a second polymer is generated, and the positive electrode of the positive electrode disposed below. It was deposited on the surface of the mixture layer.
- the distance between the emitter and the positive electrode was 300 mm.
- the electric field of the electrostatic spinning mechanism was adjusted to produce a composite fiber having an average fiber diameter of 650 nm. And composite fiber was deposited until the nonwoven fabric sheet which consists of composite fiber with a thickness of 35 micrometers was formed on the surface of the positive mix layer.
- the negative electrode and the positive electrode are laminated so that the lithium metal sheet and the positive electrode mixture layer face each other through the nonwoven fabric sheet, and then at a pressure of 1 MPa and at 90 ° C. in the lamination direction.
- the electrode group 13 was formed by hot pressing.
- the electrode group was housed in an exterior body (thickness 70 ⁇ m) made of a cylindrical laminate film having an aluminum barrier layer. At that time, a part of the positive electrode lead and the negative electrode lead was exposed from one opening of the outer package. Then, the opening of the outer package was closed by thermal welding with the positive electrode lead and the negative electrode lead 3 interposed therebetween. Next, 0.8 g of nonaqueous electrolyte was injected from the other opening of the outer package, and then degassed for 10 seconds in a reduced pressure environment of 660 mmHg.
- non-aqueous electrolyte a non-aqueous solvent in which LiClO 4 was dissolved at a concentration of 1 mol / L was used.
- non-aqueous solvent a mixed solvent of propylene carbonate and dimethoxyethane (volume ratio of 1: 1) was used.
- the part closed by thermal welding at both ends of the battery with another closed circuit voltage set to 3 V was fixed with a stretchable fixing member disposed horizontally so as to face each other.
- tool which has a curved-surface part with a curvature radius R of 20 mm was pressed on the center of the battery, and the battery was bent and deformed along the curved-surface part. After 30 seconds, the jig was pulled away from the battery and the deformation was restored. This bending deformation was repeated 10,000 times.
- the battery subjected to the bending deformation treatment was discharged at a current density of 250 ⁇ A / cm 2 in a 25 ° C. environment until the closed circuit voltage reached 1.8 V, and the discharge capacity (X) was obtained.
- the discharge curve at that time is shown as a curve Ax in FIG.
- the ratio of the capacity X to the capacity X 0 was obtained as a percentage as a capacity maintenance ratio. The results are shown in Table 1.
- Comparative Example 1 The second polymer was not used as a raw material for the nonwoven fabric sheet. That is, as the raw material liquid for the nonwoven fabric sheet, a solution containing only 10% by mass of the same first polymer vinylidene fluoride-hexafluoropropylene copolymer used in Example 1 and using dimethylacetamide as a solvent is used. A thin battery was prepared and evaluated in the same manner as in Example 1 except that. The discharge curves of the battery before and after the bending deformation treatment are shown as curves B 0 and Bx in FIG. The capacity retention rate is shown in Table 1.
- Example 2 A thin battery was prepared and evaluated in the same manner as in Example 1 except that a polymer having a core-shell structure without a cross-linked structure (weight average molecular weight 200,000) was used as the second polymer.
- a polymer having a core-shell structure a polymer having a core part containing a polystyrene structure, a shell part containing a polyethylene oxide structure, and a content of the polyethylene oxide structure being 40% by mass is used as in Example 1. It was.
- the discharge curves of the battery before and after the bending deformation treatment are shown as curves C 0 and Cx in FIG.
- the capacity retention rate is shown in Table 1.
- Examples 2 to 5 Implementation was performed except that the content of the first polymer in the total of the first polymer and the second polymer dissolved in the raw material liquid was changed to 10% by mass, 30% by mass, 60% by mass, and 70% by mass.
- a thin battery was prepared and evaluated in the same manner as in Example 1. The capacity retention rate is shown in Table 2.
- the above results indicate that when the content of the first polymer in the total of the first polymer and the second polymer is 10 to 70% by mass, a high capacity retention rate can be obtained. It can also be seen that the content of the first polymer is preferably 30 to 50% by mass.
- the thin battery of the present invention is extremely excellent in bending resistance, it is useful, for example, as a power source for devices that require flexibility to be used in contact with living skin.
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Abstract
Description
図1は、薄型電池21の概略断面図である。図2は、電池21の上面図である。図1は、図2のII-II線断面図に相当する。電池21は、電極群13と、電極群13を収納する外装体8とを備える。電極群13は、負極11、正極12、および負極11と正極12との間に介在する電解質層7を具備する。負極11は、負極集電体シート1および負極集電体シート1の一方の表面に付着した負極活物質層2を有する。正極12は、正極集電体シート4および正極集電体シート4の一方の表面に付着した正極活物質層5を有する。負極11および正極12は、電解質層7を介して、正極活物質層5と負極活物質層2とが向かい合うように配置されている。負極集電体シート1には負極リード3が接続され、正極集電体シート4には正極リード6が接続されている。負極リード3および正極リード6の一部は、外装体8から外部へ露出しており、その露出部は負極外部端子および正極外部端子として機能する。
ラミネートシート8は、無機材料層(バリア層)8aと、バリア層8aの一方の面に接着された第1の樹脂フィルム8bと、バリア層8aの他方の面に接着された第2の樹脂フィルム8cとを含む積層体である。
薄型電池は、例えば、薄型電池と電子機器とが一体となってシート化されている形態のデバイスを形成するのに適している。このような電子機器として、例えば、生体情報測定装置およびイオントフォレシス経皮投薬装置のような生体貼付型装置が挙げられる。
生体情報測定装置22は、その構成素子を保持するシート状の保持部材22aを具備する。保持部材22aは、柔軟性を有する材料で構成され、その内部から表面までの領域に、温度センサ23、感圧素子24、記憶部25、情報送信部26、ボタンスイッチSW1および制御部27が埋め込まれている。薄型電池21は、保持部材22aの内部に設けられた平坦な空間に収容されている。つまり、電池21と生体情報測定装置22は、一体となってシート化されており、電池-電子機器接合体29を構成している。
(a)正極の作製
正極は、例えば、正極活物質、導電材および結着剤を含む正極合剤を、N-メチル-2-ピロリドン(NMP)などの分散媒と混合し、正極合剤ペーストを調製し、これを、正極集電体シートに塗布し、乾燥し、圧延することにより得られる。
負極は、例えば、負極集電体シートに、リチウム金属シートまたはリチウム合金シートを圧着させて、負極集電体シートとリチウム金属シートまたはリチウム合金シートとを密着させることにより得られる。
不織布シートは、静電紡糸法により、架橋構造を有さない第1高分子と、架橋構造を有する第2高分子と、を含む原料液から、第1高分子と、第2高分子と、を含む複合繊維を生成させる工程と、生成した複合繊維を、電極表面に堆積させて、複合繊維を含む不織布シートを形成する工程と、を有する。
次に、不織布シートを介して、正極と負極とを積層して電極群を形成する。不織布シートは、正極および負極の少なくとも一方の表面に均一な厚さで形成されているため、正極活物質層と負極活物質層とが向かい合うように両電極を配置することで、非水電解質を含まない電極群を構成することができる。なお、電極群を構成する前に、負極には、負極リードが、正極に正極リードが取り付けられる。
次に、電極群を、非水電解質とともに、外装体に収容し、外装体を減圧下で密閉することにより、薄型電池が完成する。具体的には、例えば筒状に形成された外装体の一方の開口から電極群を挿入した後、その開口を熱溶着により閉じる。この時、筒状の外装体の一方の開口から正極リードおよび負極リードの一部が外部へ露出するように電極群を配置する。この露出部が正極外部端子および負極外部端子となる。次に、筒状の外装体の他方の開口から非水電解質を注入した後、減圧下で、その開口を熱溶着により閉じる。このようにして、電極群を外装体内に密閉する。非水電解質は、電極群内の空隙、主には不織布シートの空隙に含浸される。これにより、複合繊維が非水電解質で膨潤して、電解質層が形成される。
図6の製造システム100は、電極表面に複合繊維をダイレクトに堆積させて不織布シートを形成する製造ラインを構成している。製造システム100では、長尺の電極Eが製造ラインの上流から下流に搬送される。製造システム100は、長尺の電極Eの表面に連続的に不織布シートを形成する場合に用いられるが、電極の形状に応じて、製造システムの構成は適宜変更される。
以下の手順で、基本的な構造が図1、2に示す電池と同様である薄型電池を作製した。
(1)負極の作製
負極集電体シート1として、厚さ12μmの電解銅箔を準備した。その電解銅箔の一方の面に、負極活物質層2であるリチウム金属シート(厚み20μm)を100N/cmの線圧で圧着し、負極11を得た。これを5mm×5mmのタブ部を一方の短辺の中央に有する50×50mmのサイズに切り抜いた後、タブ部に銅製の負極リード3を超音波溶接した。
正極活物質である350℃で加熱した電解二酸化マンガンと、導電剤であるアセチレンブラックと、結着剤であるポリフッ化ビニリデン(PVDF)を含むN-メチル-2-ピロリドン(NMP)の溶液とを、二酸化マンガン:アセチレンブラック:PVDFの重量比が100:5:5となるように混合した後、NMPを適量加え、正極合剤ペーストを得た。
<原料液の調製>
第1高分子であるフッ化ビニリデン-ヘキサフルオロプロピレン共重合体(フッ化ビニリデン単位の含有量95モル%、重量平均分子量600,000)を5質量%含み、第2高分子であるコアシェル型構造を有する重合体(重量平均分子量1,000,000)を5質量%含む、ジメチルアセトアミドを溶媒とする溶液を調製した。このとき原料液に溶解した第1高分子と第2高分子との合計に占める第1高分子の含有量は50質量%である。
図6、7に示すような静電紡糸機構を有する装置の放出体から、原料液を放出させ、第1高分子と第2高分子を含む複合繊維を生成させ、下方に設置した正極の正極合剤層の表面に堆積させた。ここでは、放出体と正極との距離を300mmとした。また、静電紡糸機構の電界を調整して、平均の繊維径が650nmである複合繊維を生成させた。そして、正極合剤層の表面に厚さ35μmの複合繊維からなる不織布シートが形成されるまで、複合繊維を堆積させた。
リチウム金属シートと正極合剤層とが、不織布シートを介して、互いに向かい合うように、負極と正極とを積層し、その後、1MPaの圧力で、積層方向に90℃でホットプレスして、電極群13を形成した。
アルミニウム製のバリア層を有する筒状のラミネートフィルムからなる外装体(厚さ70μm)に電極群を収納した。その際、外装体の一方の開口から、正極リードと負極リードの一部を露出させた。そして、正極リードと負極リード3を挟んで外装体の開口を熱溶着により閉じた。次に、外装体の他方の開口から非水電解質0.8gを注入した後、660mmHgの減圧環境下で10秒間脱気した。
閉路電圧を3Vに設定した電池を、25℃の環境下で、閉路電圧が1.8Vに達するまで、250μA/cm2の電流密度で放電し、放電容量(X0)を求めた。そのときの放電曲線を図8に曲線A0として示す。
不織布シートの原料として第2高分子を用いなかった。すなわち、不織布シートの原料液として、実施例1で用いたのと同じ第1高分子であるフッ化ビニリデン-ヘキサフルオロプロピレン共重合体のみを10質量%含む、ジメチルアセトアミドを溶媒とする溶液を用いたこと以外、実施例1と同様に、薄型電池を作製し、同様に評価した。屈曲変形処理を施す前後の電池の放電曲線を、図10に曲線B0およびBxとして示す。また、容量維持率を表1に示す。
第2高分子として、架橋構造を有さないコアシェル構造を有する重合体(重量平均分子量200,000)を用いたこと以外、実施例1と同様に、薄型電池を作製し、同様に評価した。コアシェル型構造を有する重合体としては、実施例1と同様に、コア部分がポリスチレン構造を含み、シェル部分がポリエチレンオキサイド構造を含み、ポリエチレンオキサイド構造の含有量が40質量%である重合体を用いた。屈曲変形処理を施す前後の電池の放電曲線を、図11に曲線C0およびCxとして示す。また、容量維持率を表1に示す。
原料液に溶解させる第1高分子と第2高分子との合計に占める第1高分子の含有量を、10質量%、30質量%、60質量%および70質量%に変更したこと以外、実施例1と同様に、薄型電池を作製し、同様に評価した。容量維持率を表2に示す。
Claims (9)
- 電極群と、前記電極群を収容するフレキシブルな外装体と、を備え、
前記電極群は、シート状の正極と、シート状の負極と、前記正極と前記負極との間に介在する電解質層と、を含み、
前記電解質層は、非水電解質と、前記非水電解質を保持する不織布シートと、を含み、
前記不織布シートは、少なくとも2種の高分子が複合化された複合繊維を含み、
前記少なくとも2種の高分子は、架橋構造を有さない第1高分子と、架橋構造を有する第2高分子と、を含む、薄型電池。 - 前記複合繊維の断面は、海成分と、前記海成分に分散する島成分と、を含む海島型構造を有し、
前記島成分に前記第1高分子が含まれており、
前記海成分に前記第2高分子が含まれている、請求項1に記載の薄型電池。 - 前記複合繊維に含まれる前記第1高分子の含有量が、10~70質量%である、請求項1または2に記載の薄型電池。
- 前記第1高分子は、フッ化ビニリデン単位を有する重合体である、請求項1~3のいずれか1項に記載の薄型電池。
- 前記第2高分子は、アクリル酸エステル単位およびメタクリル酸エステル単位よりなる群から選択される少なくとも1種を有する重合体である、請求項1~4のいずれか1項に記載の薄型電池。
- 前記第2高分子は、コア部分とシェル部分とを有するコアシェル型構造、を有する重合体である、請求項1~5のいずれか1項に記載の薄型電池。
- 前記シェル部分は、少なくともポリアルキレンオキサイド構造を有する、請求項6に記載の薄型電池。
- 前記不織布シートが、静電紡糸法により、前記第1高分子および前記第2高分子を含む原料液から前記複合繊維を生成させるとともに、前記生成した複合繊維を、前記正極および前記負極の少なくとも一方の表面に堆積させることにより形成されている、請求項1~7のいずれか1項に記載の薄型電池。
- (i)シート状の正極を準備する工程と、
(ii)シート状の負極を準備する工程と、
(iii)静電紡糸法により、少なくとも、架橋構造を有さない第1高分子と、架橋構造を有する第2高分子と、を含む原料液から、前記第1高分子と、前記第2高分子と、を含む複合繊維を生成させる工程と、
(iv)前記生成した複合繊維を、前記正極および前記負極の少なくとも一方の表面に堆積させて、前記複合繊維を含む不織布シートを形成する工程と、
(v)前記不織布シートを介して、前記正極と前記負極とを積層して電極群を形成する工程と、
(vi)前記電極群を、非水電解質とともに、フレキシブルな外装体に収容し、前記外装体を減圧下で密閉する工程と、を具備する、薄型電池の製造方法。
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Cited By (5)
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TWI584517B (zh) * | 2014-06-16 | 2017-05-21 | 納米及先進材料研發院有限公司 | 用於製備撓性多孔膜的方法 |
JP2017091972A (ja) * | 2015-11-16 | 2017-05-25 | トヨタ紡織株式会社 | 電池素子用セパレータの製造方法 |
JP2019537233A (ja) * | 2017-05-22 | 2019-12-19 | エルジー・ケム・リミテッド | フレキシブル電極、その製造方法及びそれを含む二次電池 |
WO2022230908A1 (ja) * | 2021-04-28 | 2022-11-03 | 日本ゼオン株式会社 | 非水系二次電池接着層用組成物、非水系二次電池用接着層およびその製造方法、非水系二次電池用積層体およびその製造方法、ならびに、非水系二次電池 |
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Publication number | Priority date | Publication date | Assignee | Title |
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KR102249894B1 (ko) * | 2014-11-21 | 2021-05-07 | 삼성에스디아이 주식회사 | 이차 전지 |
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06295715A (ja) * | 1993-04-06 | 1994-10-21 | Mitsubishi Paper Mills Ltd | アルカリ電池セパレータ用不織布およびその製造方法 |
JP2002237332A (ja) * | 2001-02-08 | 2002-08-23 | Oji Paper Co Ltd | ポリマー電池用不織布複合化ゲル状電解質 |
JP2007125821A (ja) * | 2005-11-04 | 2007-05-24 | Toyobo Co Ltd | 複合多孔質膜、複合多孔質膜の製造方法並びにそれを用いた電池セパレーター、電池及びコンデンサ |
JP2011517704A (ja) * | 2008-02-20 | 2011-06-16 | カール・フロイデンベルク・カー・ゲー | 架橋材料を含むフリース布 |
JP2012094288A (ja) * | 2010-10-25 | 2012-05-17 | Mitsubishi Paper Mills Ltd | 電気化学素子用セパレータ及びそれを用いた電気化学素子 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0521049A (ja) * | 1991-07-12 | 1993-01-29 | Kanai Hiroyuki | アルカリ電池用セパレータ |
JPH08212995A (ja) * | 1995-02-03 | 1996-08-20 | Mitsubishi Paper Mills Ltd | アルカリ電池セパレ−タ用不織布 |
EP0872899B1 (en) * | 1995-02-17 | 2011-03-23 | Mitsubishi Paper Mills, Ltd. | Nonwoven fabric for an alkaline battery separator and method for producing the same |
JP2001283813A (ja) * | 2000-03-29 | 2001-10-12 | Mitsubishi Paper Mills Ltd | 電池用セパレータおよび電池 |
JP3974371B2 (ja) * | 2001-10-19 | 2007-09-12 | シロウマサイエンス株式会社 | ポリマーゲル電解質組成物およびその製造法 |
US7112389B1 (en) * | 2005-09-30 | 2006-09-26 | E. I. Du Pont De Nemours And Company | Batteries including improved fine fiber separators |
WO2010027063A1 (ja) * | 2008-09-04 | 2010-03-11 | ダイワボウホールディングス株式会社 | 繊維集合物、導電性基材と繊維集合物との複合体及びそれらの製造方法 |
EP2660919B1 (en) * | 2011-03-03 | 2018-06-13 | LG Chem, Ltd. | Integrated electrode assembly and secondary battery using same |
-
2013
- 2013-09-20 US US14/421,129 patent/US20150207167A1/en not_active Abandoned
- 2013-09-20 WO PCT/JP2013/005545 patent/WO2014045586A1/ja active Application Filing
- 2013-09-20 JP JP2014536602A patent/JP6108121B2/ja not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06295715A (ja) * | 1993-04-06 | 1994-10-21 | Mitsubishi Paper Mills Ltd | アルカリ電池セパレータ用不織布およびその製造方法 |
JP2002237332A (ja) * | 2001-02-08 | 2002-08-23 | Oji Paper Co Ltd | ポリマー電池用不織布複合化ゲル状電解質 |
JP2007125821A (ja) * | 2005-11-04 | 2007-05-24 | Toyobo Co Ltd | 複合多孔質膜、複合多孔質膜の製造方法並びにそれを用いた電池セパレーター、電池及びコンデンサ |
JP2011517704A (ja) * | 2008-02-20 | 2011-06-16 | カール・フロイデンベルク・カー・ゲー | 架橋材料を含むフリース布 |
JP2012094288A (ja) * | 2010-10-25 | 2012-05-17 | Mitsubishi Paper Mills Ltd | 電気化学素子用セパレータ及びそれを用いた電気化学素子 |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI584517B (zh) * | 2014-06-16 | 2017-05-21 | 納米及先進材料研發院有限公司 | 用於製備撓性多孔膜的方法 |
JP2017091972A (ja) * | 2015-11-16 | 2017-05-25 | トヨタ紡織株式会社 | 電池素子用セパレータの製造方法 |
JP2019537233A (ja) * | 2017-05-22 | 2019-12-19 | エルジー・ケム・リミテッド | フレキシブル電極、その製造方法及びそれを含む二次電池 |
JP7027642B2 (ja) | 2017-05-22 | 2022-03-02 | エルジー エナジー ソリューション リミテッド | フレキシブル電極、その製造方法及びそれを含む二次電池 |
JP7408905B2 (ja) | 2019-11-19 | 2024-01-09 | エルジー エナジー ソリューション リミテッド | 二次電池の製造方法及びその製造設備 |
WO2022230908A1 (ja) * | 2021-04-28 | 2022-11-03 | 日本ゼオン株式会社 | 非水系二次電池接着層用組成物、非水系二次電池用接着層およびその製造方法、非水系二次電池用積層体およびその製造方法、ならびに、非水系二次電池 |
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