WO2020091026A1 - Batterie secondaire à électrolyte non aqueux - Google Patents

Batterie secondaire à électrolyte non aqueux Download PDF

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Publication number
WO2020091026A1
WO2020091026A1 PCT/JP2019/042960 JP2019042960W WO2020091026A1 WO 2020091026 A1 WO2020091026 A1 WO 2020091026A1 JP 2019042960 W JP2019042960 W JP 2019042960W WO 2020091026 A1 WO2020091026 A1 WO 2020091026A1
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Prior art keywords
electrolyte secondary
aqueous electrolyte
secondary battery
electrode plate
porous layer
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PCT/JP2019/042960
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English (en)
Japanese (ja)
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孝輔 倉金
一郎 有瀬
村上　力
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住友化学株式会社
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Priority to KR1020217015735A priority Critical patent/KR102575331B1/ko
Publication of WO2020091026A1 publication Critical patent/WO2020091026A1/fr

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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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M50/40—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
    • H01M50/423—Polyamide resins
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • 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
    • 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 non-aqueous electrolyte secondary battery.
  • Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are currently widely used as batteries for devices such as personal computers, mobile phones and personal digital assistants.
  • porous base material containing polyolefin as a main component as a separator.
  • the porous base material containing polyolefin as a main component has a shutdown function of closing pores open in the porous base material at about 130 ° C. to 140 ° C. when the battery internal temperature rises due to some trouble.
  • the porous base material containing polyolefin as the main component has low heat resistance, so that it is melted by being exposed to a temperature higher than the temperature at which the shutdown function operates, resulting in a short circuit inside the battery and ignition of the battery. Or there was a risk of an explosion. Therefore, for the purpose of improving the heat resistance of the porous base material, a separator in which a porous layer containing a filler and a resin is laminated on at least one surface of the porous base material is being developed.
  • Patent Document 1 describes a battery separator formed of a porous layer containing boehmite (plate-like particles) as fine particles.
  • the present invention has been made in view of the above problems, and an object thereof is to realize a non-aqueous electrolyte secondary battery having excellent discharge capacity recovery characteristics of a battery after a charge / discharge cycle.
  • the non-aqueous electrolyte secondary battery according to Aspect 1 of the present invention is based on a porous layer containing an inorganic filler and a resin and a MIT tester method defined in JIS P 8115 (1994).
  • the folding endurance test carried out at an angle of 45 °, the positive electrode plate having a bending frequency of 130 times or more before the electrode active material layer was peeled off, and in the folding endurance test, the bending frequency until the electrode active material layer was peeled off was 1650.
  • a negative electrode plate that is more than once, and the porous layer has a value represented by the following formula (1) in the range of 0.10 to 0.42.
  • the porous layer includes a polyolefin, a (meth) acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin, and It includes a resin selected from the group consisting of water-soluble polymers.
  • the polyamide resin is an aramid resin.
  • the porous layer is laminated on one side or both sides of a polyolefin porous film.
  • the positive electrode plate contains a transition metal oxide and the negative electrode plate contains graphite.
  • a non-aqueous electrolyte secondary battery having excellent discharge capacity recovery characteristics of a battery after a charge / discharge cycle can be realized.
  • a non-aqueous electrolyte secondary battery is based on a porous layer containing an inorganic filler and a resin, a MIT tester method defined in JIS P 8115 (1994), a load of 1 N, In the folding endurance test carried out at a bending angle of 45 °, the positive electrode plate having a folding frequency of 130 times or more before the electrode active material layer was peeled off, and the folding frequency until the electrode active material layer was peeled off in the folding durability test. 1650 times or more, and the porous layer has a value represented by the following formula (1) in a range of 0.10 to 0.42.
  • the positive electrode plate in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention is not particularly limited as long as the number of bending times measured in the folding endurance test is within a specific range as described below.
  • the positive electrode active material layer a sheet-shaped positive electrode plate in which a positive electrode mixture containing a positive electrode active material, a conductive agent and a binder is carried on a positive electrode current collector is used.
  • the positive electrode plate may carry the positive electrode mixture on both surfaces of the positive electrode current collector, or may carry the positive electrode mixture on one surface of the positive electrode current collector.
  • the positive electrode active material includes, for example, a material that can be doped with lithium ions and dedoped.
  • a transition metal oxide is preferable as the material.
  • Specific examples of the transition metal oxide include a lithium composite oxide containing at least one transition metal such as V, Mn, Fe, Co and Ni.
  • Examples of the conductive agent include carbonaceous materials such as graphite (natural graphite and artificial graphite), cokes, carbon black, pyrolytic carbons, carbon fibers, and organic polymer compound fired bodies.
  • the conductive agent may be used alone or in combination of two or more kinds.
  • binder examples include polyvinylidene fluoride, vinylidene fluoride copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
  • Thermoplastics such as ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, thermoplastic polyimide, polyethylene and polypropylene Resins, acrylic resins, and styrene butadiene rubber are mentioned.
  • the binder also has a function as a thickener.
  • Examples of the positive electrode current collector include conductors such as Al, Ni, and stainless steel. Among them, Al is more preferable because it is easily processed into a thin film and is inexpensive.
  • the negative electrode plate in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention is not particularly limited as long as the number of folding times measured in the folding endurance test is within a specific range as described below.
  • a sheet-shaped negative electrode in which a negative electrode mixture containing a negative electrode active material is carried on a negative electrode current collector is used as the negative electrode active material layer.
  • the sheet-shaped negative electrode plate preferably contains the conductive agent and the binder.
  • the negative electrode plate may carry the negative electrode mixture on both surfaces of the negative electrode current collector, or may carry the negative electrode mixture on one surface of the negative electrode current collector.
  • the negative electrode active material includes, for example, a material capable of being doped / dedoped with lithium ions, lithium metal or a lithium alloy.
  • the material include a carbonaceous material and the like.
  • the carbonaceous material include graphite (natural graphite, artificial graphite), cokes, carbon black, and pyrolytic carbons.
  • the conductive agent and the binder those described as the conductive agent and the binder which can be contained in the positive electrode active material layer can be used.
  • Examples of the negative electrode current collector include Cu, Ni, and stainless steel. Particularly, in a lithium ion secondary battery, Cu is more preferable because it is difficult to form an alloy with lithium and is easily processed into a thin film.
  • the positive electrode plate and the negative electrode plate according to one embodiment of the present invention are specified in the number of bendings until the active material layer is peeled off in a folding endurance test carried out in accordance with the MIT tester method defined in JIS P 8115 (1994). The range is.
  • the folding endurance test is performed at a load of 1 N and a bending angle of 45 °. In the non-aqueous electrolyte secondary battery, expansion and contraction of the active material may occur during the charge / discharge cycle.
  • the positive electrode plate is bent 130 times or more, preferably 150 times or more, until the electrode active material layer is peeled off.
  • the negative electrode plate has a number of folding times of 1650 or more, preferably 1800 or more, and more preferably 2000 or more, before the electrode active material layer is peeled off.
  • FIG. 1 is a schematic diagram showing an outline of the MIT test machine used in the MIT test machine method.
  • the x-axis represents the horizontal direction and the y-axis represents the vertical direction.
  • the outline of the MIT test machine method will be described below.
  • One end of the test piece in the longitudinal direction is clamped with a spring-loaded clamp, and the other end is clamped with a bending clamp.
  • the spring loaded clamp is connected to the weight.
  • the load by the weight is 1N.
  • the test piece is in a state of being tensioned in the longitudinal direction. In this state, the longitudinal direction of the test piece is parallel to the vertical direction.
  • the test piece is bent by rotating the bending clamp.
  • the bending angle at this time is 45 °. That is, the test piece is bent left and right at 45 °.
  • the speed of bending the test piece is 175 reciprocations / minute.
  • Examples of the method for producing a sheet-shaped positive electrode plate include a method in which a positive electrode active material, a conductive agent, and a binder are pressure-molded on a positive electrode current collector; a positive electrode active material, a conductive agent, and Examples include a method in which the binder is made into a paste, the paste is applied to the positive electrode current collector, and then the paste is adhered to the positive electrode current collector by applying pressure in a wet state or after drying.
  • a method for producing a sheet-shaped negative electrode plate for example, a method of press-molding the negative electrode active material on a negative electrode current collector; after making the negative electrode active material into a paste using an appropriate organic solvent, Examples thereof include a method of applying the paste to the negative electrode current collector and then applying pressure in a wet state or after drying to fix the negative electrode current collector.
  • the paste preferably contains the conductive agent and the binder.
  • the pressurizing time is preferably 1 to 3600 seconds, more preferably 1 to 300 seconds.
  • the pressurization may be performed by restraining the positive electrode plate or the negative electrode plate.
  • the pressure due to restraint is also referred to as restraint pressure.
  • the binding pressure is preferably 0.01 to 10 MPa, more preferably 0.01 to 5 MPa.
  • the positive electrode plate or the negative electrode plate may be pressurized while being wetted with an organic solvent. This can improve the adhesion between the components contained in the electrode active material layer and the adhesion between the electrode active material layer and the current collector.
  • the organic solvent include carbonates, ethers, esters, nitriles, amides, carbamates and sulfur-containing compounds, and fluorine-containing organic solvents obtained by introducing a fluorine group into these organic solvents. ..
  • the porous layer may be disposed between the polyolefin porous film and at least one of the positive electrode plate and the negative electrode plate as a member constituting the non-aqueous electrolyte secondary battery.
  • the porous layer may be formed on one side or both sides of the polyolefin porous film.
  • the porous layer may be formed on the active material layer of at least one of the positive electrode plate and the negative electrode plate.
  • the porous layer may be arranged between the polyolefin porous film and at least one of the positive electrode plate and the negative electrode plate so as to be in contact with them.
  • the porous layer disposed between the polyolefin porous film and at least one of the positive electrode plate and the negative electrode plate may be one layer or two or more layers.
  • the porous layer is preferably an insulating porous layer containing a resin.
  • the porous layer is laminated on one side of the polyolefin porous film
  • the porous layer is preferably laminated on the surface of the polyolefin porous film facing the positive electrode plate. More preferably, the porous layer is laminated on the surface in contact with the positive electrode plate.
  • the porous layer in one embodiment of the present invention contains an inorganic filler and a resin.
  • the porous layer has a large number of pores inside and has a structure in which these pores are connected, and is a layer through which gas or liquid can pass from one surface to the other surface.
  • the porous layer in one embodiment of the present invention is used as a member constituting a non-aqueous electrolyte secondary battery laminated separator described below, the porous layer is an electrode as an outermost layer of the laminated separator. Can be a layer in contact with.
  • the resin contained in the porous layer in one embodiment of the present invention is preferably insoluble in the electrolytic solution of the battery and is electrochemically stable in the usage range of the battery.
  • the resin include polyolefins; (meth) acrylate resins; fluorine-containing resins; polyamide resins; polyimide resins; polyester resins; rubbers; melting points or glass transition temperatures of 180 ° C. or higher.
  • Resins water-soluble polymers; polycarbonates, polyacetals, polyether ether ketones and the like.
  • polyolefin, (meth) acrylate resin, fluorine-containing resin, polyamide resin, polyester resin and water-soluble polymer are preferable.
  • polyethylene polyethylene, polypropylene, polybutene, ethylene-propylene copolymer and the like are preferable.
  • fluorine-containing resin examples include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Coalescence, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoro Examples thereof include propylene-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer and the like, and fluorine-containing rubber having a glass transition temperature of 23 ° C. or lower among the fluor
  • polyamide resin aramid resins such as aromatic polyamide and wholly aromatic polyamide are preferable.
  • the aramid resin examples include poly (paraphenylene terephthalamide), poly (metaphenylene isophthalamide), poly (parabenzamide), poly (metabenzamide), poly (4,4′-benzanilide terephthalate). Amide), poly (paraphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (metaphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide), Poly (metaphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer, metaphenylene terephthalamide / 2 , 6-diclosure Paraphenylene terephthalamide copolymer and the like. Of these, poly (paraphenylene
  • polyester resin aromatic polyester such as polyarylate and liquid crystal polyester are preferable.
  • Examples of rubbers include styrene-butadiene copolymer and its hydride, methacrylic acid ester copolymer, acrylonitrile-acrylic acid ester copolymer, styrene-acrylic acid ester copolymer, ethylene propylene rubber, polyvinyl acetate and the like. Can be mentioned.
  • Examples of the resin having a melting point or glass transition temperature of 180 ° C. or higher include polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyetherimide, polyamideimide, and polyetheramide.
  • water-soluble polymers examples include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, polymethacrylic acid and the like.
  • the resin contained in the porous layer in the embodiment of the present invention may be one kind or a mixture of two or more kinds.
  • a fluorine-containing resin is preferable because it can be easily maintained.
  • the porous layer in one embodiment of the present invention contains an inorganic filler.
  • the lower limit of the content is preferably 50% by weight or more and 70% by weight or more based on the total weight of the filler and the resin constituting the porous layer in the embodiment of the present invention. More preferably, it is more preferably 90% by weight or more.
  • the upper limit of the content of the inorganic filler in the porous layer in the embodiment of the present invention is preferably 99% by weight or less, and more preferably 98% by weight or less.
  • the content of the filler is preferably 50% by weight or more from the viewpoint of heat resistance, and the content of the filler is preferably 99% by weight or less from the viewpoint of adhesion between the fillers.
  • the inorganic filler is not particularly limited as long as it is a filler that is stable in a non-aqueous electrolytic solution and is electrochemically stable. From the viewpoint of ensuring the safety of the battery, a filler having a heat resistant temperature of 150 ° C. or higher is preferable.
  • the inorganic filler is not particularly limited, but is usually an insulating filler.
  • the inorganic filler is preferably an inorganic material containing at least one element selected from the group consisting of aluminum element, zinc element, calcium element, zirconium element, silicon element, magnesium element, barium element, and boron element, and preferably Is an inorganic substance containing an aluminum element. Further, the inorganic filler preferably contains an oxide of the metal element.
  • the inorganic filler titanium oxide, alumina (Al 2 O 3 ), zinc oxide (ZnO), calcium oxide (CaO), zirconia oxide (ZrO 2 ), silica, magnesia, barium oxide, boron oxide, Examples thereof include mica, wollastonite, attapulgite, and boehmite (alumina monohydrate).
  • the inorganic filler one kind of filler may be used alone, or two or more kinds of filler may be used in combination.
  • the inorganic filler in the porous layer in one embodiment of the present invention preferably contains alumina and a plate-like filler.
  • the plate-like filler include one or more fillers selected from the group consisting of zinc oxide (ZnO), mica, and boehmite among the oxides of the metal elements listed above.
  • the volume average particle size of the inorganic filler is preferably in the range of 0.01 ⁇ m to 10 ⁇ m from the viewpoint of ensuring good adhesiveness and slipperiness, and moldability of the laminate.
  • the lower limit value is more preferably 0.05 ⁇ m or more, further preferably 0.1 ⁇ m or more.
  • the upper limit value is more preferably 5 ⁇ m or less, further preferably 1 ⁇ m or less.
  • the shape of the inorganic filler is arbitrary and is not particularly limited.
  • the shape of the inorganic filler may be a particle shape, for example, a spherical shape; an elliptical shape; a plate shape; a rod shape; an indefinite shape; a fibrous shape; a spherical or columnar single particle such as a peanut shape and / or a tetrapot shape.
  • the shape may be any of the above.
  • the inorganic filler is preferably plate-like particles and / or non-aggregated primary particles.
  • the shape of the inorganic filler is such that the particles in the porous material are difficult to be most closely packed, voids are easily formed between the particles, bumps, dents, constrictions, ridges or bulges, and dendritic
  • a single particle is heat-fused such as an indeterminate shape such as a shape, a coral shape, or a tuft shape; a fibrous shape; a peanut shape and / or a tetrapot shape.
  • the shape of the inorganic filler is particularly preferably a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped particles are heat-sealed.
  • the filler can improve slipperiness by forming fine irregularities on the surface of the porous layer.
  • the filler is a plate-like particle and / or a primary particle that is not aggregated, the unevenness formed on the surface of the porous layer by the filler becomes finer, and the adhesiveness between the porous layer and the electrode is further improved. It will be good.
  • the oxygen atom mass percentage of the metal oxide constituting the inorganic filler contained in the porous layer in one embodiment of the present invention is preferably 10% to 50%, more preferably 20% to 50%. preferable.
  • the affinity between the solvent or the dispersion medium in the coating liquid used in the method for producing a porous layer described later and the inorganic filler is preferably adjusted. It is possible to maintain the distance between the above-mentioned inorganic fillers at an appropriate distance. As a result, the dispersibility of the coating liquid can be improved, and as a result, the above formula (1) can be controlled within an appropriate specified range.
  • the porous layer in one embodiment of the present invention may contain other components than the above-mentioned inorganic filler and resin.
  • the other components include surfactants, waxes and binder resins.
  • the content of the other components is preferably 0% by weight to 50% by weight based on the weight of the entire porous layer.
  • the average film thickness of the porous layer in one embodiment of the present invention is preferably in the range of 0.5 ⁇ m to 10 ⁇ m per one layer of the porous layer from the viewpoint of ensuring adhesiveness to the electrode and high energy density. More preferably, it is in the range of 1 ⁇ m to 5 ⁇ m.
  • the basis weight per unit area of the porous layer can be appropriately determined in consideration of the strength, film thickness, weight and handling property of the porous layer.
  • the basis weight per unit area of the porous layer is preferably 0.5 to 20 g / m 2 and more preferably 0.5 to 10 g / m 2 per porous layer.
  • the weight energy density and volume energy density of the non-aqueous electrolyte secondary battery can be increased.
  • the basis weight of the porous layer exceeds the above range, the non-aqueous electrolyte secondary battery tends to be heavy.
  • the porosity of the porous layer is preferably 20 to 90% by volume, and more preferably 30 to 80% by volume so that sufficient ion permeability can be obtained.
  • the pore size of the pores of the porous layer is preferably 1.0 ⁇ m or less, more preferably 0.5 ⁇ m or less. By setting the pore diameters to these sizes, the non-aqueous electrolyte secondary battery can obtain sufficient ion permeability.
  • the value represented by the following formula (1) is preferably in the range of 0.10 to 0.42, and in the range of 0.10 to 0.30. More preferably.
  • T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD
  • M represents a scratch test under a constant load of 0.1 N in MD.
  • the ratio of the distance (T) to the critical load in TD and the distance (M) to the critical load in MD measured by the above scratch test is an index showing the orientation of the inorganic filler in the porous layer. ..
  • FIG. 2 shows a schematic diagram of the state of the inorganic filler in the porous layer when the orientation is high (anisotropic) and when the orientation is low (isotropic). The left view of FIG.
  • FIG. 2 is a schematic view showing the structure of the porous layer containing an inorganic filler, in which the orientation of the inorganic filler is large and exhibits anisotropy, and the right view of FIG. It is a schematic diagram showing the structure of the said porous layer in case the orientation of an inorganic filler is small and it shows isotropic property.
  • the value represented by the above formula (1) is a value indicating the anisotropy of the distance to the critical load in the scratch test. The closer the value is to zero, the more isotropic the distance to the critical load is. Indicates that there is.
  • the value represented by the formula (1) is also simply referred to as “formula (1)”.
  • the "scratch test" in the present invention means, as shown in FIG. 3, a constant load is applied to the indenter, and the porous membrane is moved horizontally while the surface layer of the porous membrane to be measured is compressed and deformed in the thickness direction.
  • This is a test for measuring the stress generated at a certain indenter movement distance when the pressure is applied.
  • the state in which the surface layer of the porous membrane is compressed and deformed in the thickness direction is the state in which the indenter is pushed into the porous membrane.
  • the test is specifically carried out by the following method: (1) A laminate, which is a laminated porous film obtained by laminating a measurement target porous layer on a porous substrate, is cut into 20 mm ⁇ 60 mm.
  • the cut laminated body 3 is pasted on a 30 mm ⁇ 70 mm glass preparation, which is the substrate 2, with an aqueous paste, and dried at 25 ° C. for 24 hours to prepare a test sample. ..
  • bubbles are prevented from entering between the laminated body and the glass slide.
  • the test sample prepared in the step (1) is installed in a micro scratch test device. With the diamond indenter 1 in the test apparatus, while the vertical load of 0.1 N is applied to the test sample, the table in the test apparatus is directed toward the TD of the laminated body at 5 mm / min. At speed, move a distance of 10 mm.
  • a frictional force which is a stress generated between the diamond indenter and the test sample.
  • a curve graph showing the relationship between the displacement of the stress measured in the step (2) and the moving distance of the table is created, and from the curve graph, as shown in FIG. Calculate the value and the distance to reach the critical load.
  • the moving direction of the table is changed to MD, and the above steps (1) to (3) are repeated to calculate the critical load value and the distance to reach the critical load in MD.
  • the distance to the critical load value calculated by the scratch test is (a) an index of plastic deformation easiness of the surface of the laminated porous film, (b) an index of transmissibility of shear stress to the surface opposite to the measurement surface. Becomes The long distance to the critical load value means that in the laminated porous film to be measured, (a ') the surface layer portion is less likely to be plastically deformed, and (b') the transmission of shear stress to the surface opposite to the measurement surface. Is low, that is, it is difficult for stress to be transmitted.
  • the ion permeation resistance of the porous layer increases, and the resistance of the separator in the non-aqueous electrolyte secondary battery increases.
  • the above formula (1) is less than 0.10, it is considered that the structure of the porous layer is a structure having an excessively high isotropic property.
  • the structure of the porous layer has an excessively high isotropic property, in a non-aqueous electrolyte secondary battery incorporating the porous layer, the electrolyte receiving ability of the porous layer during battery operation tends to be excessively high. There is.
  • the electrolyte solution supply capabilities of the separator base material and the electrode that are in contact with the porous layer and supply the electrolyte solution to the porous layer will control the flow rate of the electrolyte solution of the entire non-aqueous electrolyte secondary battery.
  • the resistance of the separator in the non-aqueous electrolyte secondary battery increases.
  • the median particle diameter (D50) of the inorganic filler is preferably in the range of 0.1 ⁇ m to 11 ⁇ m, more preferably in the range of 0.1 ⁇ m to 10 ⁇ m, and 0 The range is more preferably from 1 ⁇ m to 5 ⁇ m, and particularly preferably 0.5 ⁇ m.
  • the method for measuring the median particle diameter of the inorganic filler is not particularly limited, but for example, it is measured by the method described in the examples.
  • the center particle size of the inorganic filler is larger than 11 ⁇ m, the film thickness of the heat-resistant layer increases and unevenness occurs, resulting in unevenness in ion permeation of the porous layer. As a result, the resistance of the separator in the non-aqueous electrolyte secondary battery incorporating the porous layer tends to increase.
  • the median particle diameter of the inorganic filler is less than 0.1 ⁇ m, the viscosity of the coating liquid containing the inorganic filler becomes high, which may cause dilatancy. As a result, the coating liquid may have poor coating performance and uneven coating on the porous layer may occur.
  • the central particle diameter of the inorganic filler is small, the amount of binder required to bind the inorganic filler increases.
  • the ion permeation resistance of the porous layer increases, and the resistance of the separator in the non-aqueous electrolyte secondary battery increases.
  • the BET specific surface area per unit area of the inorganic filler is preferably 100 m 2 / g or less, more preferably 50 m 2 / g or less, and 10 m 2 / g. It may be the following.
  • the method for measuring the BET specific surface area per unit area of the inorganic filler is not particularly limited, and examples thereof include a method including the steps (1) to (3) below.
  • the pretreatment device and the measurement device are not particularly limited.
  • BELPREP-vacII manufactured by Microtrac Bell Co., Ltd.
  • BELSORP-mini manufactured by Microtrac Bell Co., Ltd.
  • the measurement conditions for measuring the specific surface area of the filler are not particularly limited and can be appropriately set by those skilled in the art.
  • the BET specific surface area per unit area of the inorganic filler is larger than 100 m 2 / g, the filler oiling property is increased due to the increase in the BET specific surface area, and accordingly, the properties of the porous layer as a coating liquid are decreased, There is a risk of poor coatability. As a result, the resistance of the separator in the non-aqueous electrolyte secondary battery incorporating the porous layer tends to increase.
  • the method for producing the porous layer according to the embodiment of the present invention is not particularly limited, but for example, one of the following steps (1) to (3) may be used on the substrate, A method of forming a porous layer containing the inorganic filler and the resin can be mentioned.
  • the porous layer can be produced by depositing the resin and then drying it to remove the solvent.
  • the coating liquid in steps (1) to (3) may be in a state in which the inorganic filler is dispersed and the resin is dissolved.
  • the solvent can be said to be a solvent for dissolving the resin and a dispersion medium for dispersing the resin or the inorganic filler.
  • the base material After applying a coating liquid containing the inorganic filler and the resin on the surface of the base material, the base material is immersed in a deposition solvent that is a poor solvent for the resin, A step of depositing a resin to form a porous layer.
  • the liquid property of the coating liquid is made acidic by using a low-boiling organic acid, A step of depositing a resin to form a porous layer.
  • the solvent does not adversely affect the base material, dissolves the resin uniformly and stably, and disperses the inorganic filler uniformly and stably.
  • the solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, acetone and water.
  • the deposition solvent for example, isopropyl alcohol or t-butyl alcohol is preferably used.
  • the low boiling point organic acid for example, paratoluenesulfonic acid, acetic acid, etc. can be used.
  • the coating amount (that is, basis weight) of the porous layer is usually 0.5 to 20 g / solid per one layer of the porous layer from the viewpoint of adhesiveness to an electrode or an electrode sheet and ion permeability. is preferably m 2, more preferably from 0.5 ⁇ 10g / m 2, more preferably in the range of 0.5g / m 2 ⁇ 1.5g / m 2. That is, it is preferable to adjust the amount of the coating liquid applied on the substrate so that the coating amount (area weight) of the obtained porous layer falls within the above range.
  • a coating containing an inorganic filler and a resin used for producing the porous layer examples thereof include adjusting the solid content concentration of the working liquid, and adjusting the coating shear rate when the coating liquid is applied onto the substrate.
  • a suitable solid content concentration of the coating liquid may vary depending on the type of filler, etc., but generally it is preferably more than 20% by weight and 40% by weight or less. It is preferable for the solid content concentration to be in the above range from the viewpoint that the viscosity of the coating liquid can be appropriately maintained and, as a result, the above formula (1) can be controlled within an appropriate prescribed range.
  • the coating shear rate at the time of applying the coating liquid on the substrate may vary depending on the type of filler, etc., but generally it is preferably 2 (1 / s) or more and 4 (1 / s). More preferably, it is from s) to 50 (1 / s).
  • the inorganic filler a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped are heat-fused, spherical-shaped, elliptical-shaped, plate-shaped, rod-shaped, or irregular-shaped.
  • the coating shear rate is increased, a high shearing force is applied to the inorganic filler, so that the anisotropy tends to increase.
  • the coating shear rate is reduced, the shearing force is not applied to the inorganic filler, so that the inorganic filler tends to be oriented isotropically.
  • the inorganic filler is a long fiber diameter inorganic filler such as long wollastonite having a large fiber diameter
  • the coating shear rate is increased, the long fibers are entangled with each other, or the long blades of the doctor blade are long fibers. Tend to be in a disoriented orientation due to the trapping of the, and anisotropy tends to be low.
  • the coating shear rate is reduced, the long fibers do not become entangled with each other and do not get caught by the blade of the doctor blade, so that they tend to be oriented and the anisotropy tends to increase.
  • a separator for a non-aqueous electrolyte secondary battery according to an embodiment of the present invention includes a polyolefin porous film.
  • the separator for a non-aqueous electrolyte secondary battery may further include other layers such as an adhesive layer, a heat resistant layer, and a protective layer, in addition to the polyolefin porous film.
  • the non-aqueous electrolyte secondary battery in one embodiment of the present invention may include a polyolefin porous film.
  • a polyolefin porous film may only be called a "porous film.”
  • the porous film contains a polyolefin-based resin as a main component and has a large number of pores connected to the inside thereof, so that a gas and a liquid can pass from one surface to the other surface.
  • the porous film alone can serve as a separator for a non-aqueous electrolyte secondary battery. It can also serve as a porous base material in the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated.
  • a laminate in which the porous layer is laminated in the present specification, also referred to as "non-aqueous electrolyte secondary battery laminated separator” or “laminated separator” ..
  • the proportion of polyolefin in the porous film is 50% by volume or more of the entire porous film, more preferably 90% by volume or more, and further preferably 95% by volume or more. Further, it is more preferable that the polyolefin contains a high molecular weight component having a weight average molecular weight of 5 ⁇ 10 5 to 15 ⁇ 10 6 . In particular, when the polyolefin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, the strength of the separator for a non-aqueous electrolyte secondary battery is improved, which is more preferable.
  • the polyolefin which is a thermoplastic resin
  • a copolymer may be used.
  • the homopolymer include polyethylene, polypropylene and polybutene.
  • the copolymer include ethylene-propylene copolymer.
  • polyethylene is more preferable because it can block excessive current from flowing at lower temperatures. Note that blocking the flow of this excessive current is also referred to as shutdown.
  • the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene- ⁇ -olefin copolymer), and ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more. Among these, ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more is more preferable.
  • the thickness of the porous film is preferably 4 to 40 ⁇ m, more preferably 5 to 30 ⁇ m, and further preferably 6 to 15 ⁇ m.
  • the basis weight per unit area of the porous film can be appropriately determined in consideration of strength, film thickness, weight and handleability.
  • the basis weight is preferably 4 to 20 g / m 2 , and preferably 4 to 12 g / m 2 so that the weight energy density and the volume energy density of the non-aqueous electrolyte secondary battery can be increased. More preferably, it is more preferably 5 to 10 g / m 2 .
  • the air permeability of the porous film is preferably 30 to 500 sec / 100 mL in Gurley value, and more preferably 50 to 300 sec / 100 mL.
  • the air permeability of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated on the porous film is preferably 30 to 1000 sec / 100 mL in terms of Gurley value, and is 50 to 800 sec / 100 mL. Is more preferable. Since the laminated separator for a non-aqueous electrolyte secondary battery has the above-mentioned air permeability, it is possible to obtain sufficient ion permeability in the non-aqueous electrolyte secondary battery.
  • the porosity of the porous film is preferably 20 to 80% by volume so as to increase the holding amount of the electrolytic solution and to surely prevent the flow of an excessive current at a lower temperature. It is more preferably 30 to 75% by volume.
  • the pore size of the pores of the porous film is 0.3 ⁇ m or less so that sufficient ion permeability can be obtained and particles can be prevented from entering the positive electrode plate and the negative electrode plate. Is preferably 0.14 ⁇ m or less, and more preferably 0.14 ⁇ m or less.
  • the method for producing the polyolefin porous film is not particularly limited.
  • a sheet-shaped polyolefin resin composition is prepared by kneading a polyolefin resin, a pore-forming agent such as an inorganic filler and a plasticizer, and optionally an antioxidant and the like and then extruding the kneaded product. After removing the pore-forming agent from the sheet-shaped polyolefin resin composition with an appropriate solvent, the polyolefin resin composition from which the pore-forming agent has been removed may be stretched to produce a polyolefin porous film. it can.
  • the above-mentioned inorganic filler is not particularly limited, and examples thereof include inorganic fillers, specifically calcium carbonate and the like.
  • the plasticizer is not particularly limited, and examples thereof include low molecular weight hydrocarbons such as liquid paraffin.
  • a method including the following steps can be mentioned.
  • A a step of kneading an ultrahigh molecular weight polyethylene, a low molecular weight polyethylene having a weight average molecular weight of 10,000 or less, a pore forming agent such as calcium carbonate or a plasticizer, and an antioxidant to obtain a polyolefin resin composition
  • B a step of rolling the obtained polyolefin resin composition with a pair of rolling rollers and gradually cooling it while pulling it with a take-up roller having a different speed ratio to form a sheet
  • C a step of removing the pore forming agent from the obtained sheet with a suitable solvent
  • D A step of stretching the sheet from which the pore forming agent has been removed at an appropriate stretching ratio.
  • Examples of the method for producing a laminated separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention include, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, The method of using a polyolefin porous film can be mentioned.
  • the non-aqueous electrolyte that can be included in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention is not particularly limited as long as it is a non-aqueous electrolyte that is generally used in non-aqueous electrolyte secondary batteries.
  • a non-aqueous electrolyte obtained by dissolving a lithium salt in an organic solvent can be used.
  • lithium salt examples include LiClO 4 , LiPF 6 , LiAsF 6 , LiSbF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , Li 2 B 10 Cl. 10 , lower aliphatic carboxylic acid lithium salt, LiAlCl 4 and the like.
  • the lithium salt may be used alone or in combination of two or more kinds.
  • organic solvent that constitutes the non-aqueous electrolytic solution
  • examples of the organic solvent that constitutes the non-aqueous electrolytic solution include carbonates, ethers, esters, nitriles, amides, carbamates and sulfur-containing compounds, and fluorine-containing compounds introduced into these organic solvents. Fluorine organic solvents and the like can be mentioned.
  • the organic solvent may be used alone or in combination of two or more.
  • Examples of the method for producing the non-aqueous electrolyte secondary battery according to the embodiment of the present invention include the following methods. First, the positive electrode plate, the porous layer, the non-aqueous electrolyte secondary battery separator, and the negative electrode plate are arranged in this order to form a non-aqueous electrolyte secondary battery member. After that, the member for a non-aqueous electrolyte secondary battery is put in a container that will be the casing of the non-aqueous electrolyte secondary battery, and then the inside of the container is filled with the non-aqueous electrolyte solution and then sealed while depressurizing. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
  • the non-aqueous electrolyte secondary battery according to one embodiment of the present invention is, as described above, a separator for a non-aqueous electrolyte secondary battery including a polyolefin porous film, a porous layer, a positive electrode plate, and a negative electrode plate. And are equipped with.
  • the non-aqueous electrolyte secondary battery according to the embodiment of the present invention satisfies the following requirements (i) to (iii).
  • the porous layer has a value represented by the following formula (1) in the range of 0.10 to 0.42.
  • T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD
  • M represents a scratch test under a constant load of 0.1 N in MD.
  • the porous layer Due to the requirement of (i), in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention, the porous layer has a uniform and dense structure, so that the distribution of lithium ions in the porous layer is uniform. Retained. Then, due to the requirements (ii) and (iii), the entire electrode easily isotropically follows the expansion and contraction of the active material. Therefore, the adhesiveness between the components contained in the electrode active material layer and the adhesiveness between the electrode active material layer and the current collector are easily maintained.
  • a MIT type folding endurance tester manufactured by Yasuda Seiki
  • load 1N
  • bent portion R 0.38mm
  • bending speed 175 reciprocations / minute one end of the test piece was fixed, and the test piece was bent left and right at an angle of 45 degrees.
  • the number of times of bending until the electrode active material layer was peeled from the positive electrode plate or the negative electrode plate was measured.
  • the number of times of bending here is the number of times of reciprocal bending displayed on the counter of the MIT folding endurance tester.
  • an arabic Yamato aqueous liquid paste (manufactured by Yamato Co., Ltd.) diluted 5 times with water was applied on the separator side of the cut laminate, that is, the entire surface of the porous substrate side, in a small amount of about 1.5 g / m 2 per unit area. It was applied thinly.
  • the surface coated with the aqueous liquid paste was pasted on a glass slide having a size of 30 mm ⁇ 70 mm and then dried at 25 ° C. for 24 hours to prepare a test sample. At the time of the above-mentioned bonding, bubbles were prevented from entering between the laminate and the glass slide.
  • step (2) The test sample prepared in step (1) was placed in a micro scratch tester (manufactured by CSEM Instruments). With the diamond indenter (conical shape having an apex angle of 120 ° and a tip radius of 0.2 mm) in the test apparatus, a vertical load of 0.1 N was applied to the test sample in the test apparatus. The table was moved toward the TD of the laminate at a speed of 5 mm / min and a distance of 10 mm. During that time, the stress generated between the diamond indenter and the test sample, that is, the frictional force was measured. (3) A curve graph showing the relationship between the displacement of the stress measured in the step (2) and the moving distance of the table was created. From the curve graph, the critical load value in TD and the distance to reach the critical load were calculated. (4) The moving direction of the table was changed to MD, and the above steps (1) to (3) were repeated to calculate the critical load value and the distance to reach the critical load in MD.
  • the thicknesses of the porous layer, the porous substrate, the positive electrode active material layer and the negative electrode active material layer were measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation.
  • the thickness of the positive electrode active material layer is calculated by subtracting the thickness of the aluminum foil that is the current collector from the thickness of the positive electrode plate, and the thickness of the negative electrode active material layer is the thickness of the negative electrode plate. It was calculated by subtracting the thickness of the copper foil, which is the current collector, from. Further, the thickness of the porous layer was calculated by subtracting the thickness of the uncoated portion from the thickness of the coated portion of each laminate.
  • the coated portion refers to the portion where the porous layer is formed, and the uncoated portion refers to the portion where the porous layer is not formed.
  • the volume-based particle size distribution of the filler was calculated by measuring D10, D50, and D90 using a laser diffraction particle size distribution analyzer SALD2200 manufactured by Shimadzu Corporation.
  • SALD2200 laser diffraction particle size distribution analyzer
  • the particle diameter at which the cumulative distribution based on volume is 50%, the particle diameter at 10%, and the particle diameter at 90% are called D50, D10, and D90, respectively.
  • D50 is also referred to as the median particle size.
  • the specific surface area of the filler was measured using BELSORP-mini (manufactured by Microtrac Bell Co., Ltd.).
  • the adsorption-desorption isotherm by nitrogen of the filler that had been vacuum dried at a pretreatment temperature of 80 ° C. for 8 hours was measured by the constant volume method, and calculated by the BET method.
  • Various conditions in the constant volume method are as follows: adsorption temperature; 77 K, adsorbate; nitrogen, saturated vapor pressure; measured value, adsorbate cross section; 0.162 nm 2 , equilibrium waiting time (adsorption equilibrium state (adsorption Waiting time after the pressure change during desorption reaches a value below a predetermined value)): 500 sec.
  • the pore volume was calculated by the MP method and the BJH method, and the pretreatment device used was BELPREP-vacII (manufactured by Microtrac Bell Co., Ltd.).
  • CC-CV charging is a charging method in which charging is performed with a set constant current, and after reaching a predetermined voltage, the current is reduced while maintaining the voltage.
  • CC discharge is a method of discharging to a predetermined voltage with a set constant current. The meanings of these terms are the same in this specification.
  • the discharge capacity at the third cycle was defined as the discharge recovery capacity. In Table 1 described later, the discharge recovery capacity is shown as “discharge recovery capacity after 100 cycles”.
  • the above-mentioned discharge recovery capacity test is a test method in which discharge is carried out at a low rate (0.2 C) after 100 charge / discharge cycles and the discharge capacity is confirmed more accurately. In particular, the degree of deterioration of the discharge performance of the electrode can be confirmed.
  • This sheet was immersed in an aqueous hydrochloric acid solution prepared by mixing 0.5 mol% of a nonionic surfactant in 4 mol / L hydrochloric acid to dissolve and remove calcium carbonate. Then, the said sheet
  • (B layer)) (Production of coating liquid)
  • the inorganic filler hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
  • D50, D10, and D90 of the inorganic filler 1 were 0.4 ⁇ m, 0.2 ⁇ m, and 2.1 ⁇ m, respectively.
  • the BET specific surface area per unit area of the inorganic filler 1 was 7.3 m 2 / g.
  • a binder resin As a binder resin, a vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Ltd .: trade name “KYNAR2801”) was used.
  • the inorganic filler, vinylidene fluoride-hexafluoropropylene copolymer and solvent were mixed in the following proportions. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with 90 parts by weight of inorganic filler, and the solid content in the resulting mixed liquid (inorganic filler and vinylidene fluoride-hexafluoropropylene copolymer).
  • the solvent was mixed so that the concentration of was 37% by weight.
  • the obtained mixed liquid was stirred and mixed with a thin film swivel type high speed mixer (Filmiku (registered trademark) manufactured by Primix Co., Ltd.) to obtain a uniform coating liquid 1.
  • the obtained coating liquid 1 was applied to one surface of the A layer by a doctor blade method at a coating shear rate of 3.9 (1 / s) to form a coating film on one surface of the A layer. ..
  • the coating film was dried at 65 ° C. for 20 minutes to form a B layer on one surface of the A layer.
  • a laminated body 1 laminated on which the B layer was laminated on one surface of the A layer was obtained.
  • the weight of the B layer was 7 g / m 2 and the thickness was 4 ⁇ m.
  • a positive electrode plate 1 was obtained.
  • the thickness of the positive electrode active material layer was 38 ⁇ m.
  • Negative electrode plate A negative electrode mixture of natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) having a volume-based average particle diameter (D50) of 15 ⁇ m was used as a negative electrode current collector ( A negative electrode plate laminated on one surface of the copper foil) was obtained. A binding pressure (0.7 MPa) was applied to this negative electrode plate at room temperature for 30 seconds.
  • a negative electrode plate 1 was obtained.
  • the thickness of the negative electrode active material layer was 38 ⁇ m.
  • a non-aqueous electrolyte secondary battery was manufactured using the positive electrode plate 1, the negative electrode plate 1 and the laminate 1 by the method described below.
  • the positive electrode plate 1 and the negative electrode plate 1 were arranged such that the entire main surface of the positive electrode active material layer of the positive electrode plate 1 was included in the range of the main surface of the negative electrode active material layer of the negative electrode plate 1. That is, the positive electrode plate 1 and the negative electrode plate 1 were arranged so that the entire main surface of the positive electrode active material layer of the positive electrode plate 1 overlaps the main surface of the negative electrode active material layer of the negative electrode plate 1. Further, the surface of the laminated body 1 on the side of the porous layer was opposed to the positive electrode active material layer of the positive electrode plate 1.
  • the non-aqueous electrolyte secondary battery member 1 was placed in a previously prepared bag in which an aluminum layer and a heat seal layer were laminated, and 0.23 mL of the non-aqueous electrolyte solution was further placed in this bag. It was The non-aqueous electrolyte solution should be dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 so that the concentration of LiPF 6 is 1 mol / L. Was prepared by. Then, the inside of the bag was depressurized and the bag was heat-sealed to manufacture the non-aqueous electrolyte secondary battery 1.
  • Example 2 [Preparation of porous layer and laminate]
  • the inorganic filler 2 a mixture of spherical alumina (Sumitomo Chemical Co., Ltd., trade name AA03) and mica (Wako Pure Chemical Industries, Ltd., trade name: non-swelling synthetic mica) was used. The above mixture was prepared by mixing 50 parts by weight of spherical alumina and 50 parts by weight of mica in a mortar. The oxygen atom mass percentage of the inorganic filler 2 was 45%. Further, D50, D10 and D90 of the inorganic filler 2 were 4.2 ⁇ m, 0.5 ⁇ m and 11.5 ⁇ m, respectively. Furthermore, the BET specific surface area per unit area of the inorganic filler 2 was 4.5 m 2 / g.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 90 parts by weight of inorganic filler, and the solid content in the resulting mixed liquid (inorganic filler + vinylidene fluoride-hexafluoropropylene copolymer). The solvent was mixed so that the concentration of was 30% by weight. The obtained mixed liquid was stirred and mixed by a thin film swivel type high speed mixer to obtain a uniform coating liquid 2.
  • the inorganic filler 1 used for producing the porous layer (B layer) was changed to the above inorganic filler 2, the coating liquid 1 was changed to the above coating liquid 2, and the coating shear rate was 7.9 (1 / s).
  • a layered product 2 was obtained in the same manner as in Example 1 except that the content was changed to).
  • a non-aqueous electrolyte secondary battery 2 was obtained in the same manner as in Example 1 except that the laminate 2 was used instead of the laminate 1.
  • Example 3 [Preparation of porous layer and laminate]
  • wollastonite (Hayashi Kasei Co., Ltd., trade name: Wollastonite VM-8N) having an oxygen atomic mass percentage of 42% was used.
  • D50, D10, and D90 of the inorganic filler 3 were 10.6 ⁇ m, 2.4 ⁇ m, and 25.3 ⁇ m, respectively.
  • the BET specific surface area per unit area of the inorganic filler 3 was 1.3 m 2 / g.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 90 parts by weight of inorganic filler, and the solid content in the resulting mixed liquid (inorganic filler + vinylidene fluoride-hexafluoropropylene copolymer). The solvent was mixed so that the concentration of was 40% by weight. The obtained mixed liquid was stirred and mixed with a thin film swivel type high speed mixer to obtain a uniform coating liquid 3.
  • the inorganic filler 1 used in the preparation of the porous layer (B layer) was changed to the above inorganic filler 3, the coating liquid 1 was changed to the above coating liquid 3, and the coating shear rate was 7.9 (1 / s A laminated body 3 was obtained in the same manner as in Example 1 except that the layer structure 3 was changed to).
  • a non-aqueous electrolyte secondary battery 3 was obtained in the same manner as in Example 1 except that the laminate 3 was used instead of the laminate 1.
  • Example 4 [Preparation of porous layer and laminate]
  • the inorganic filler 4 a mixture of ⁇ -alumina (Sumitomo Chemical Co., Ltd., trade name: AKP3000) and hexagonal plate-shaped zinc oxide (Sakai Chemical Industry Co., Ltd., trade name: XZ-1000F) was used.
  • the above mixture was prepared by mixing 99 parts by weight of ⁇ -alumina and 1 part by weight of hexagonal plate-shaped zinc oxide in a mortar.
  • the oxygen atom mass percentage of the inorganic filler 4 was 47%.
  • D50, D10, and D90 of the inorganic filler 4 were 0.8 ⁇ m, 0.4 ⁇ m, and 2.2 ⁇ m, respectively.
  • the BET specific surface area per unit area of the inorganic filler 4 was 4.5 m 2 / g.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 90 parts by weight of inorganic filler, and the solid content in the resulting mixed liquid (inorganic filler + vinylidene fluoride-hexafluoropropylene copolymer). The solvent was mixed so that the concentration of was 40% by weight. The obtained mixed liquid was stirred and mixed by a thin film swivel type high speed mixer to obtain a uniform coating liquid 4.
  • the inorganic filler 1 used for producing the porous layer (B layer) was changed to the above inorganic filler 4, the coating liquid 1 was changed to the above coating liquid 4, and the coating shear rate was 39.4 (1 / s).
  • a layered product 4 was obtained in the same manner as in Example 1 except that the content was changed to).
  • a positive electrode plate 2 was obtained.
  • the thickness of the positive electrode active material layer was 37 ⁇ m.
  • a non-aqueous electrolyte secondary battery 4 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the positive electrode plate 2 was used as the positive electrode plate.
  • Example 5 (Positive plate) A positive electrode plate was obtained in which the positive electrode mixture (LiCoO 2 / conductive agent / PVDF (weight ratio: 100/5/3)) was laminated on one surface of the positive electrode current collector (aluminum foil). A binding pressure (0.7 MPa) was applied at room temperature for 30 seconds while the positive electrode plate was wet with diethyl carbonate.
  • the positive electrode mixture LiCoO 2 / conductive agent / PVDF (weight ratio: 100/5/3)
  • a binding pressure 0.7 MPa
  • the positive electrode plate is cut so that the size of the part where the positive electrode active material layer is laminated is 45 mm ⁇ 30 mm, and the part where the positive electrode active material layer is not laminated is left on the outer periphery of the positive electrode plate so as to remain. Board 3 was obtained.
  • the thickness of the positive electrode active material layer was 38 ⁇ m.
  • a non-aqueous electrolyte secondary battery 5 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the positive electrode plate 3 was used as the positive electrode plate.
  • Example 6 (Negative electrode plate) A negative electrode plate in which a negative electrode mixture of natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) was laminated on one side of a negative electrode current collector (copper foil) It was A binding pressure (0.7 MPa) was applied for 30 seconds at room temperature while the negative electrode plate was wet with diethyl carbonate.
  • a negative electrode plate 2 was obtained.
  • the thickness of the negative electrode active material layer was 37 ⁇ m.
  • a non-aqueous electrolyte secondary battery 6 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the negative electrode plate 2 was used as the negative electrode plate.
  • Example 7 (Negative electrode plate) A negative electrode plate was obtained in which a negative electrode mixture of artificial spherulite graphite / conductive agent / PVDF (weight ratio 85/15 / 7.5) was laminated on one surface of a negative electrode current collector (copper foil). A binding pressure (0.7 MPa) was applied for 30 seconds at room temperature while the negative electrode plate was wet with diethyl carbonate.
  • a negative electrode plate 3 was obtained.
  • the thickness of the negative electrode active material layer was 36 ⁇ m.
  • a non-aqueous electrolyte secondary battery 7 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the negative electrode plate 3 was used as the negative electrode plate.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 90 parts by weight of inorganic filler, and the solid content in the resulting mixed liquid (inorganic filler + vinylidene fluoride-hexafluoropropylene copolymer). The solvent was mixed so that the concentration of was 40% by weight. The obtained mixed liquid was stirred and mixed by a thin film swivel type high speed mixer to obtain a uniform coating liquid 5.
  • the inorganic filler 1 used in the preparation of the porous layer (B layer) was changed to the above inorganic filler 5, the coating liquid 1 was changed to the above coating liquid 5, and the coating shear rate was 7.9 (1 / s A layered product 5 was obtained in the same manner as in Example 1 except that the content was changed to).
  • a non-aqueous electrolyte secondary battery 8 was obtained in the same manner as in Example 1 except that the laminate 5 was used instead of the laminate 1.
  • the positive electrode plate 4 was used.
  • the thickness of the positive electrode active material layer was 38 ⁇ m.
  • a non-aqueous electrolyte secondary battery 9 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the positive electrode plate 4 was used as the positive electrode plate.
  • the negative electrode plate 4 was used.
  • the thickness of the negative electrode active material layer was 38 ⁇ m.
  • a non-aqueous electrolyte secondary battery 10 was obtained in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the negative electrode plate 4 was used as the negative electrode plate.
  • Example 2 In Table 1, two types of compounds and numerical values are described in the “inorganic filler” column of Examples 2 and 4 to 7 and Comparative Examples 2 to 3. The numerical value represents the weight part of the compound. For example, in Example 2, "Al 2 O 3 / mica 50/50" is described, which means that 50 parts by weight of Al 2 O 3 and 50 parts by weight of mica were used.
  • the non-aqueous electrolyte secondary batteries of Examples 1 to 7 have excellent discharge capacity recovery characteristics after charge / discharge cycles as compared with the non-aqueous electrolyte secondary batteries of Comparative Examples 1 to 3. I found out.
  • the number of folds until the electrode active material layer of the positive electrode plate was peeled was 130 times or more, and the number of folds until the electrode active material layer of the negative electrode plate was peeled was 1650. It is more than once, and the value represented by
  • Comparative Example 2 the number of bending times before peeling off the electrode active material layer of the positive electrode plate was less than 130 times. In Comparative Example 3, the number of times of bending until the electrode active material layer of the negative electrode plate was peeled off was less than 1650.
  • the non-aqueous electrolyte secondary battery according to an embodiment of the present invention is excellent in discharge capacity recovery characteristics after charge / discharge cycles, and thus is suitable as a battery used for personal computers, mobile phones, personal digital assistants, and the like, and a vehicle battery. Can be used for.

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Abstract

La présente invention a pour objet d'obtenir une batterie secondaire à électrolyte non aqueux présentant d'excellentes caractéristiques de récupération de capacité de décharge après des cycles de charge/décharge. Une batterie secondaire à électrolyte non aqueux selon la présente invention comprend : une couche poreuse contenant une charge inorganique et une résine ; une plaque d'électrode positive qui peut supporter au moins 130 événements de flexion jusqu'à ce qu'une couche de matériau actif d'électrode soit décollée ; et une plaque d'électrode négative qui peut supporter au moins 1650 événements de flexion, la couche poreuse ayant une valeur d'essai de dureté par rayage représentée par une équation spécifique dans la plage de 0,10-0,42.
PCT/JP2019/042960 2018-11-01 2019-11-01 Batterie secondaire à électrolyte non aqueux WO2020091026A1 (fr)

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US11805600B2 (en) 2020-07-28 2023-10-31 Saint-Gobain Performance Plastics Corporation Dielectric substrate and method of forming the same

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JP6657055B2 (ja) 2015-11-30 2020-03-04 住友化学株式会社 非水電解液二次電池用セパレータ
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JP2009272243A (ja) * 2008-05-09 2009-11-19 Mitsui Mining & Smelting Co Ltd 非水電解液二次電池
JP2016009544A (ja) * 2014-06-23 2016-01-18 ユニチカ株式会社 二次電池電極用バインダー、スラリー、二次電池電極および二次電池
JP2017226122A (ja) * 2016-06-21 2017-12-28 住友化学株式会社 積層体
WO2018101474A1 (fr) * 2016-12-02 2018-06-07 旭化成株式会社 Particules inorganiques pour pile à électrolyte non aqueux
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220033617A1 (en) * 2020-07-28 2022-02-03 Saint-Gobain Performance Plastics Corporation Dielectric substrate and method of forming the same
US11805600B2 (en) 2020-07-28 2023-10-31 Saint-Gobain Performance Plastics Corporation Dielectric substrate and method of forming the same

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