WO2020091059A1 - Nonaqueous electrolyte secondary battery - Google Patents

Nonaqueous electrolyte secondary battery Download PDF

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Publication number
WO2020091059A1
WO2020091059A1 PCT/JP2019/043095 JP2019043095W WO2020091059A1 WO 2020091059 A1 WO2020091059 A1 WO 2020091059A1 JP 2019043095 W JP2019043095 W JP 2019043095W WO 2020091059 A1 WO2020091059 A1 WO 2020091059A1
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Prior art keywords
porous layer
secondary battery
electrolyte secondary
aqueous electrolyte
electrode plate
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PCT/JP2019/043095
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French (fr)
Japanese (ja)
Inventor
一郎 有瀬
孝輔 倉金
村上　力
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住友化学株式会社
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Priority to KR1020217015731A priority Critical patent/KR20210082493A/en
Publication of WO2020091059A1 publication Critical patent/WO2020091059A1/en

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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
    • H01M10/056—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
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • 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
    • 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
    • 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
    • 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
    • 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 especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, etc. because of their high energy density, and recently they have been developed as in-vehicle batteries. Has been.
  • the present invention has been made in view of the above problems, and an object thereof is a non-aqueous electrolyte secondary that can exhibit excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles. To provide batteries.
  • 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 which is more than one times, and the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0, and the wide-angle X-ray of the porous layer is provided.
  • 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.
  • non-aqueous electrolyte secondary battery that can exhibit an excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles.
  • 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 of the negative electrode plate, the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0, the wide angle X of the porous layer.
  • the range of the maximum value of the peak intensity ratio is 1 In the range of 5 to 300, a non-aqueous electrolyte secondary battery.
  • the non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention may further include a polyolefin porous film described below.
  • 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 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 included in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention are JIS In the folding endurance test carried out according to the MIT tester method defined in P 8115 (1994), the number of times of bending until the electrode active material layer is peeled off is within a specific range. 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, the electrode active material may expand and contract during the charge / discharge cycle.
  • the positive electrode plate has a bending frequency of 130 times or more before the electrode active material layer is peeled off, and more preferably 150 times or more.
  • 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.
  • Examples of the method for producing the sheet-shaped negative electrode plate include, for example, a method in which the negative electrode active material is pressure-molded on a negative electrode current collector; the negative electrode active material is made into a paste using an appropriate organic solvent, and then the paste is used as a negative electrode. Examples thereof include a method of applying to a current collector and then applying pressure to the negative electrode current collector in a wet state or after drying, and the like.
  • 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 in one embodiment of the present invention is a porous layer containing an inorganic filler and a resin, and the inorganic filler on the surface of the porous layer (hereinafter, may be referred to as “porous layer surface”).
  • Peak intensity: I (hkl) and I (abc) satisfy the following formula (1), and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300.
  • 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 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 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 of the polyolefin porous film that is 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 laminated separator for a non-aqueous electrolyte secondary battery described later, the porous layer is for the non-aqueous electrolyte secondary battery.
  • the outermost layer of the laminated separator can be a layer in contact with the electrode.
  • polyolefins polyolefins, polyester resins, (meth) acrylate resins, fluorine-containing resins, polyamide resins and water-soluble polymers are preferable.
  • polyethylene polyethylene, polypropylene, polybutene, ethylene-propylene copolymer and the like are preferable.
  • 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.
  • a fluorine-containing resin is preferable because it is easy to do.
  • 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 oxides of the above elements.
  • 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 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 oxygen atom mass percentage of the oxide of the element forming the inorganic filler contained in the porous layer is preferably 10% to 50%, and preferably 20% to 50%. Is more preferable.
  • the aspect ratio of the inorganic filler itself is in the above range, when the porous layer in one embodiment of the present invention is formed by the method described below, in the resulting porous layer, the orientation of the filler, The uniformity of the distribution of the filler on the surface of the porous layer can be controlled within a preferable 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 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 aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is an index showing the uniformity of the distribution of the inorganic filler on the porous layer, especially on the surface thereof.
  • the aspect ratio is close to 1
  • the shape and distribution of the constituent material on the surface of the porous layer are uniform, and it is easy to be densely packed.
  • the aspect ratio is large, the arrangement of the constituent components in the surface structure of the porous layer becomes non-uniform, and as a result, the uniformity of the shape and distribution of the openings of the surface of the porous layer deteriorates.
  • the aspect ratio is greater than 4.0, the uniformity of the shape and distribution of the porous layer, especially the surface openings thereof, is excessively reduced, so that a non-aqueous electrolyte secondary electrode incorporating the porous layer is used.
  • the aspect ratio is less than 1.4, the porous layer, in particular, the distribution of the inorganic filler on the surface thereof has an excessively uniform structure, and as a result, the surface opening area of the porous layer is small.
  • the non-aqueous electrolyte secondary battery incorporating the porous layer the ability of the porous layer to receive the electrolytic solution at the time of battery operation decreases. As a result, it is considered that the battery rate characteristic of the non-aqueous electrolyte secondary battery is deteriorated.
  • the method for measuring the peak intensities I (hkl) and I (abc) and the peak intensity ratio I (hkl) / I (abc) is not particularly limited.
  • the following (1) to (3) are used.
  • a method comprising the steps shown can be mentioned.
  • (1) A step of preparing a measurement sample by cutting a 2 cm square laminate (laminated porous film) obtained by laminating a porous layer on a substrate.
  • the measurement sample obtained in step (1) is mounted on an Al holder with the porous layer side of the sample as the measurement surface, and an X-ray profile is obtained by a wide-angle X-ray diffraction method (2 ⁇ - ⁇ scan method). Measuring step.
  • the device for measuring the X-ray profile and the measurement conditions are not particularly limited.
  • the output may be measured at 50 KV-200 mA and a scan speed of 2 ° / min.
  • I (abc) satisfy the equation (1), the peak intensity ratio calculated by the equation (2) is calculated, and the maximum value of the peak intensity ratio, that is, the degree of orientation of the porous layer is calculated.
  • the maximum value of the peak intensity ratio represented by the formula (2) is larger than 300, the anisotropy of the internal structure of the porous layer becomes excessively high, and the ion permeation flow channel length inside the porous layer is increased. become longer. As a result, in the non-aqueous electrolyte secondary battery incorporating the porous layer, it is considered that the ion permeation resistance of the porous layer increases and the battery rate characteristics of the non-aqueous electrolyte secondary battery deteriorate.
  • the maximum value of the peak intensity ratio represented by the above formula (2) is less than 1.5, compared to the case where the porous layer having the peak intensity ratio of 1.5 or more is used,
  • the ions supplied from the electrodes are permeated at high speed. Therefore, the supply of ions from the electrode becomes rate-determining (that is, the ions are depleted on the electrode surface), and the limiting current, which is the battery operating current value condition, becomes small. As a result, it is considered that the battery rate characteristic of the non-aqueous electrolyte secondary battery is deteriorated.
  • 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.
  • steps (2) and (3) shown below a 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.
  • a step of forming a porous layer by applying a coating liquid containing the inorganic filler and the resin onto a substrate and drying and removing the solvent in the coating liquid.
  • 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 orientation of the porous layer in one embodiment of the present invention that is, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”
  • the solid content concentration of the coating liquid containing the inorganic filler and the resin, and the coating shear rate when coating the coating liquid on the substrate The adjustment can be mentioned.
  • 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. That the solid content concentration is in the above range, the viscosity of the coating liquid is appropriately maintained, and as a result, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”. Is preferable because it can be controlled within the above-mentioned preferable 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.
  • 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 separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention 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 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 and the negative electrode. Is preferable, and 0.14 ⁇ m or less is more preferable.
  • 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 mixture. 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 inorganic filler is not particularly limited, and examples thereof include inorganic fillers, specifically calcium carbonate.
  • 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.
  • Method for producing laminated separator for non-aqueous electrolyte secondary battery As a method for producing a laminated separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, the polyolefin The method using a 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.
  • a method for manufacturing the non-aqueous secondary battery according to the embodiment of the present invention a conventionally known manufacturing method can be adopted.
  • a positive electrode plate, a polyolefin porous film, and a negative electrode plate are arranged in this order to form a member for a non-aqueous electrolyte secondary battery.
  • the porous layer may be present between the polyolefin porous film and at least one of the positive electrode plate and the negative electrode plate.
  • the member for a non-aqueous electrolyte secondary battery is put in a container which is a casing of the non-aqueous electrolyte secondary battery. After filling the inside of the container with the non-aqueous electrolyte, the container is sealed while reducing the pressure. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
  • Film thickness (unit: ⁇ m) The thickness of the polyolefin porous film and the porous layer was measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. The film thickness of the porous layer was a value obtained by subtracting the film thickness of the part where the porous layer was not formed from the film thickness of the part where the porous layer was formed in each laminate.
  • An OHP film was placed on the obtained SEM image to create a projected image laid out along the contours of the particles of the inorganic filler, and the projected image was taken by a digital still camera.
  • the obtained photograph data is loaded into a computer, and the aspect ratio of each of 100 particles is calculated using the free image analysis software IMAGEJ issued by the National Institutes of Health (NIH).
  • the average was defined as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer in the porous layer (hereinafter, also referred to as “surface filler aspect ratio”).
  • each particle of the inorganic filler was approximated to an ellipse, the major axis diameter and the minor axis diameter were calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter was defined as the aspect ratio per inorganic filler.
  • the peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in the wide-angle X-ray diffraction measurement of the porous layer are represented by the following formula (1 ).
  • the peak intensity ratio calculated by I (hkl) / I (abc) in the case of satisfying (1) is calculated, and the maximum value of the peak intensity ratio is calculated. I (hkl) > I (abc) ... (1).
  • 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.
  • 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 charge recovery capacity test is a test method for confirming the charge capacity more accurately after performing discharge at a low rate (0.2 C) after the charge / discharge cycle to empty the internal capacity of the battery. It is possible to confirm the degree of deterioration of the charging performance, particularly the degree of deterioration of the charging performance of the electrodes.
  • Example 1 [Production of Porous Substrate (A Layer)] A porous substrate, which is a polyolefin porous film, was produced using polyethylene, which is a polyolefin.
  • this polyethylene resin composition was rolled with a pair of rolls whose surface temperature was set to 150 ° C. to prepare a sheet.
  • 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.
  • seat was drawn 6 times at 105 degreeC, and the porous base material (A layer) made from polyethylene was produced.
  • the porosity of the porous substrate was 53%, the basis weight was 7 g / m 2 , and the film thickness was 16 ⁇ m.
  • the inorganic filler hexagonal plate-shaped zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) having an oxygen atom mass percentage of 20% was used.
  • the inorganic filler be the inorganic filler 1.
  • the volume-based particle size distribution of the inorganic filler was calculated by measuring D10, D50, and D90 using a laser diffraction particle size distribution analyzer SALD2200 manufactured by Shimadzu Corporation.
  • 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.
  • D10, D50, and D90 of the inorganic filler 1 were 0.2 ⁇ m, 0.4 ⁇ m, and 2.1 ⁇ m, respectively.
  • binder resin a vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Ltd .; trade name “KYNAR2801”) was used.
  • the specific surface area of the inorganic filler was calculated by the BET method by measuring the adsorption-desorption isotherm with nitrogen using a constant volume method. Specifically, in Examples and Comparative Examples, the BET specific surface area per unit mass 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.
  • 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.).
  • the BET specific surface area per unit mass of the inorganic filler 1 was 7.3 m 2 / g.
  • Inorganic filler 1, vinylidene fluoride-hexafluoropropylene copolymer and solvent (N-methyl-2-pyrrolidinone manufactured by Kanto Chemical Co., Inc.) were mixed in the following proportions. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 1 (90 parts by weight) of the inorganic filler, and the solid content of the inorganic filler 1 and the vinylidene fluoride-hexafluoropropylene copolymer was mixed. A solvent was mixed so that the concentration of the mixed solution would be 37% by weight to prepare a mixed solution. 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. The coating liquid is referred to as coating liquid 1.
  • the 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. Then, the coating film was dried at 65 ° C. for 20 minutes to form a B layer on one surface of the A layer. As a result, a laminate 1 (laminated separator) in 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 of the positive electrode plate 1 was 38 ⁇ m.
  • Nitative electrode plate As the negative electrode mixture, natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethylcellulose (weight ratio 98/1/1) having a volume-based average particle size (D50) of 15 ⁇ m was used as a negative electrode current collector.
  • the negative electrode plate was obtained by laminating the copper foil on one surface. A binding pressure (0.7 MPa) was applied to the 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 of the negative electrode plate 1 was 38 ⁇ m.
  • a positive electrode plate 1, a laminate 1 and a negative electrode plate 1 were laminated (arranged) in this order in a laminate pouch to obtain a non-aqueous electrolyte secondary battery member 1.
  • 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 was prepared by dissolving LiPF 6 in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate at a volume ratio of 3: 5: 2 so as to be 1 mol / L. .. Then, the inside of the bag was depressurized and the bag was heat-sealed to manufacture the non-aqueous electrolyte secondary battery 1. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 1 were measured. The results are shown in Table 1.
  • Example 2 [Preparation of porous layer and laminate]
  • the inorganic filler 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 mixture was prepared by mixing 50 parts by weight of spherical alumina and 50 parts by weight of mica in a mortar. Let the said mixture be the inorganic filler 2.
  • the oxygen atom mass percentage of the inorganic filler 2 was 45%.
  • D10, D50, and D90 of the inorganic filler 2 were 0.5 ⁇ m, 4.2 ⁇ m, and 11.5 ⁇ m, respectively.
  • the BET specific surface area per unit mass 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 inorganic filler 2 (90 parts by weight), and the solid content of inorganic filler 2 and vinylidene fluoride-hexafluoropropylene copolymer was mixed. The solvent was mixed so that the concentration of the above was 30% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 2.
  • the inorganic filler used in the production of the porous layer (B layer) was changed to the inorganic filler 2, the coating liquid was changed to the coating liquid 2, and the coating shear rate was 7.9 (1 / s).
  • a laminate 2 was obtained in the same manner as in Example 1 except that the changes were made.
  • 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 2 were measured. The results are shown in Table 1.
  • Example 3 [Preparation of porous layer and laminate]
  • wollastonite (Wallastonite VM-8N, manufactured by Hayashi Kasei Co., Ltd.) having an oxygen atomic mass percentage of 42% was used.
  • the wollastonite is the inorganic filler 3.
  • D10, D50, and D90 of the inorganic filler 3 were 2.4 ⁇ m, 10.6 ⁇ m, and 25.3 ⁇ m, respectively.
  • the BET specific surface area per unit mass 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 is mixed with inorganic filler 3 (90 parts by weight), and the solid content of inorganic filler 3 and vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the above was 40% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed with the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 3.
  • the inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 3, the coating liquid was changed to the coating liquid 3, and the coating shear rate was 7.9 (1 / s).
  • a laminate 3 was obtained in the same manner as in Example 1 except that the changes were made.
  • 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 3 were measured. The results are shown in Table 1.
  • Example 4 [Preparation of porous layer and laminate]
  • the inorganic filler 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 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. Let the said mixture be the inorganic filler 4.
  • the oxygen atom mass percentage of the inorganic filler 4 was 47%.
  • D10, D50, and D90 of the inorganic filler 4 were 0.4 ⁇ m, 0.8 ⁇ m, and 2.2 ⁇ m, respectively. Furthermore, the BET specific surface area per unit mass 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 inorganic filler 4 (90 parts by weight), and the solid content of inorganic filler 4 and vinylidene fluoride-hexafluoropropylene copolymer was mixed. The solvent was mixed so that the concentration of the above would be 40% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 4.
  • the inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 4, the coating liquid was changed to the 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 it was changed.
  • a positive electrode plate 2 was obtained.
  • the thickness of the positive electrode active material layer of the positive electrode plate 2 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 4 were measured. The results are shown in Table 1.
  • Example 5 Preparation of non-aqueous electrolyte secondary battery] (Positive plate) A positive electrode plate was obtained by laminating LiCoO 2 / conductive agent / PVDF (weight ratio: 100/5/3) as a positive electrode mixture on one side of an aluminum foil that is a positive electrode current collector. With the positive electrode plate wet with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the positive electrode plate at room temperature for 30 seconds.
  • LiCoO 2 / conductive agent / PVDF weight ratio: 100/5/3
  • the positive electrode plate By cutting the positive electrode plate so that the size of the portion where the positive electrode active material layer is laminated is 45 mm ⁇ 30 mm, and the portion where the positive electrode active material layer is not laminated is left on its outer periphery with a width of 13 mm. A positive electrode plate 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 5 were measured. The results are shown in Table 1.
  • Example 6 Preparation of non-aqueous electrolyte secondary battery] (Negative electrode plate) By laminating natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) as a negative electrode mixture on one side of a copper foil which is a negative electrode current collector, I got a board. With the negative electrode plate moistened with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the negative electrode plate at room temperature for 30 seconds.
  • a binding pressure 0.7 MPa
  • a negative electrode plate 2 was obtained.
  • the thickness of the negative electrode active material layer of the negative electrode plate 2 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 6 were measured. The results are shown in Table 1.
  • Example 7 Preparation of non-aqueous electrolyte secondary battery] (Negative electrode plate) As a negative electrode mixture, artificial spherulite graphite / conductive agent / PVDF (weight ratio 85/15 / 7.5) was laminated on one surface of a copper foil as a negative electrode current collector to obtain a negative electrode plate. With the negative electrode plate moistened with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the negative electrode plate at room temperature for 30 seconds.
  • a binding pressure 0.7 MPa
  • a negative electrode plate 3 was obtained.
  • the thickness of the negative electrode active material layer of the negative electrode plate 3 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 7 were measured. The results are shown in Table 1.
  • Attapulgite manufactured by Hayashi Kasei Co., Ltd., trade name: ATTAGEL # 50
  • the attapulgite is the inorganic filler 5.
  • D10, D50, and D90 of the inorganic filler 5 were 0.4 ⁇ m, 2.0 ⁇ m, and 3.3 ⁇ m, respectively.
  • the BET specific surface area per unit mass of the inorganic filler 5 was 235.0 m 2 / g.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with 5 (90 parts by weight) of the inorganic filler, and the solid content of the inorganic filler 5 and the vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the mixed solution would be 17% by weight to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 5.
  • the inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 5, the coating liquid was changed to the coating liquid 5, and the coating shear rate was 1.3 (1 / s).
  • a laminate 5 was obtained in the same manner as in Example 1 except that the changes were made.
  • 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 8 were measured. The results are shown in Table 1.
  • the inorganic filler As the inorganic filler, mica (manufactured by Wako Pure Chemical Industries, trade name: non-swelling mica) having an oxygen atomic mass percentage of 44% was used. Let the mica be the inorganic filler 6. D10, D50, and D90 of the inorganic filler 6 were 0.5 ⁇ m, 5.5 ⁇ m, and 12.1 ⁇ m, respectively. The BET specific surface area per unit mass of the inorganic filler 5 was 3.2 m 2 / g.
  • the coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with inorganic filler 6 (90 parts by weight), and the solid content of inorganic filler 6 and vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the mixed solution would be 20% by weight to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 6.
  • the inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 6, the coating liquid was changed to the coating liquid 6, and the coating shear rate was 0.4 (1 / s).
  • a layered product 6 was obtained in the same manner as in Example 1 except that it was changed.
  • a non-aqueous electrolyte secondary battery 9 was obtained in the same manner as in Example 1 except that the laminate 6 was used instead of the laminate 1. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 9 were measured. The results are shown in Table 1.
  • the positive electrode plate By cutting the positive electrode plate so that the size of the portion where the positive electrode active material layer is laminated is 45 mm ⁇ 30 mm, and the portion where the positive electrode active material layer is not laminated is left on its outer periphery with a width of 13 mm. , And the positive electrode plate 4.
  • the thickness of the positive electrode active material layer of the positive electrode plate 4 was 38 ⁇ m.
  • a non-aqueous electrolyte secondary battery 10 was produced 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 10 were measured. The results are shown in Table 1.
  • the negative electrode plate By cutting the negative electrode plate so that the size of the portion where the negative electrode active material layer is laminated is 50 mm ⁇ 35 mm, and the portion where the negative electrode active material layer is not laminated remains on the outer periphery with a width of 13 mm. , And the negative electrode plate 4.
  • the thickness of the negative electrode active material layer of the negative electrode plate 4 was 38 ⁇ m.
  • Nonaqueous electrolysis was performed in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1, the positive electrode plate 4 was used as the positive electrode plate, and the negative electrode plate 4 was used as the negative electrode plate. A liquid secondary battery 11 was produced. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 11 were measured. The results are shown in Table 1.
  • Example 2 Two types of compounds and numerical values are described in the "filler" column of Examples 2 and 4 to 7 and Comparative Examples 3 and 4.
  • the numerical value represents the weight part of the compound.
  • 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 were compared with the non-aqueous electrolyte secondary batteries of Comparative Examples 1 to 4 in charge recovery capacity after 100 cycles of charge and discharge.
  • the non-aqueous electrolyte secondary battery according to an embodiment of the present invention which satisfies the requirement of the number of times of bending of the positive electrode plate and the negative electrode plate until the electrode active material layer is peeled off in the folding endurance test, has a large number of cycles of 100 cycles. It was revealed that even after the charge / discharge cycle, the charge recovery capacity was excellent.
  • the porous layer has a uniform and dense structure, so that the ion permeability in the porous layer is maintained in a good state, and the ions in the porous layer are maintained. Is evenly distributed. Further, by satisfying the requirement (iii), even when the electrode active material expands and contracts in the course of the charge / discharge cycle, the active material, the conductive agent and the binder which are components contained in the electrode active material layer And the adhesion between the electrode active material layer and the current collector are maintained well, and deterioration of the electrode is suppressed. As a result, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention satisfying all the requirements (i) to (iii) has a good charge recovery capacity even after 100 cycles. Can be maintained.
  • the non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention can exhibit an excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles, and thus can be used in personal computers, mobile phones, and portable information. It can be suitably used as a battery used for a terminal or the like, and a vehicle-mounted battery.

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Abstract

The purpose of the present invention is to provide a nonaqueous electrolyte secondary battery with excellent charge recovery capacity even after a charge/discharge cycle. This nonaqueous electrolyte secondary battery is provided with: a positive electrode plate and a negative electrode plate in which the number of bendings before the active substance layer is peeled off is at least a prescribed number; and a porous layer in which the aspect ratio of a projected image of an inorganic filler on the surface is 1.4-4.0, and the maximum value of the peak intensity ratio I(hkl)/I(abc) is in the range 1.5-300.

Description

非水電解液二次電池Non-aqueous electrolyte secondary battery
　本発明は、非水電解液二次電池に関する。 The present invention relates to a non-aqueous electrolyte secondary battery.
　非水電解液二次電池、特にリチウムイオン二次電池は、エネルギー密度が高いのでパーソナルコンピュータ、携帯電話、携帯情報端末などに用いる電池として広く使用され、また最近では車載用の電池として開発が進められている。 Non-aqueous electrolyte secondary batteries, especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, etc. because of their high energy density, and recently they have been developed as in-vehicle batteries. Has been.
　非水電解液二次電池として、例えば、特許文献１に記載されたような板状の無機フィラーを含有し、空孔率が６０～９０％である多孔質層を多孔質基材の少なくとも一面に積層させた非水系二次電池用セパレータを備える非水電解液二次電池が知られている。 As a non-aqueous electrolyte secondary battery, for example, a porous layer containing a plate-like inorganic filler as described in Patent Document 1 and having a porosity of 60 to 90% is provided on at least one surface of a porous substrate. There is known a non-aqueous electrolyte secondary battery including a non-aqueous secondary battery separator that is laminated on.
特開２０１０－１０８７５３号公報（２０１０年５月１３日公開）Japanese Unexamined Patent Publication No. 2010-108753 (Published May 13, 2010)
　しかしながら、上述のような従来技術に係る多孔質層を備えた非水電解液二次電池は、充放電サイクルを経た後の充電回復容量の観点からは改善の余地があった。 However, the non-aqueous electrolyte secondary battery including the porous layer according to the related art as described above has room for improvement in terms of charge recovery capacity after undergoing a charge / discharge cycle.
　本発明は前記の問題点に鑑みてなされたものであり、その目的は、多数回の充放電サイクルを経た後であっても、優れた充電回復容量を示すことができる非水電解液二次電池を提供することにある。 The present invention has been made in view of the above problems, and an object thereof is a non-aqueous electrolyte secondary that can exhibit excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles. To provide batteries.
　本発明の態様１に係る非水電解液二次電池は、無機フィラーと樹脂とを含む多孔質層と、ＪＩＳ　Ｐ　８１１５（１９９４）に規定されたＭＩＴ試験機法に準拠し、荷重１Ｎ、折り曲げ角度４５°にて実施した耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１３０回以上である正極板と、前記耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１６５０回以上である負極板と、を備え、前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、１．４～４．０の範囲であり、前記多孔質層の、広角Ｘ線回折法により測定した、互いに直交する任意の回折面（hkl）、（abc）のピーク強度：Ｉ（hkl）およびＩ（abc）が下式（１）を満たし、下式（２）で算出されるピーク強度比の最大値の範囲が、１．５～３００の範囲である。
Ｉ（hkl）　＞　Ｉ（abc）・・・（１）
Ｉ（hkl）　／　Ｉ（abc）・・・（２）
　また、本発明の態様２に係る非水電解液二次電池は、前記態様１において、前記多孔質層が、ポリオレフィン、（メタ）アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂、ポリエステル系樹脂および水溶性ポリマーからなる群より１種以上選択される樹脂を含む。 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). In 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 which is more than one times, and the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0, and the wide-angle X-ray of the porous layer is provided. The peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) which are orthogonal to each other measured by the diffraction method satisfy the following equation (1) and are calculated by the following equation (2). The maximum value of the peak intensity ratio is 1.5 300 is in the range of.
I (hkl) > I (abc)・ ・ ・ (1)
I (hkl) / I (abc)・ ・ ・ (2)
Further, in the non-aqueous electrolyte secondary battery according to Aspect 2 of the present invention, in the Aspect 1, 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.
　また、本発明の態様３に係る非水電解液二次電池は、前記態様２において、前記ポリアミド系樹脂がアラミド樹脂である。 Further, in the non-aqueous electrolyte secondary battery according to Aspect 3 of the present invention, in the Aspect 2, the polyamide resin is an aramid resin.
　また、本発明の態様４に係る非水電解液二次電池は、前記態様１～３のいずれかにおいて、前記多孔質層が、ポリオレフィン多孔質フィルムの片面または両面に積層されている。 Further, in the non-aqueous electrolyte secondary battery according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, the porous layer is laminated on one side or both sides of a polyolefin porous film.
　また、本発明の態様５に係る非水電解液二次電池は、前記態様１～４のいずれかにおいて、前記正極板が、遷移金属酸化物を含み、前記負極板が、黒鉛を含む。 Further, in the non-aqueous electrolyte secondary battery according to Aspect 5 of the present invention, in any one of Aspects 1 to 4, the positive electrode plate contains a transition metal oxide and the negative electrode plate contains graphite.
　本発明の一態様によれば、多数回の充放電サイクルを経た後であっても優れた充電回復容量を示すことができる非水電解液二次電池を提供することができる。 According to one aspect of the present invention, it is possible to provide a non-aqueous electrolyte secondary battery that can exhibit an excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles.
ＭＩＴ試験機の概略を示す模式図である。It is a schematic diagram which shows the outline of a MIT test machine. 無機フィラーを含む多孔質層における、無機フィラーの配向性が大きい場合（左図）および無機フィラーの配向性が小さい場合（右図）の、当該多孔質層の構造を表す模式図である。It is a schematic diagram showing the structure of the said porous layer when the orientation of an inorganic filler is large in the porous layer containing an inorganic filler (left figure), and when the orientation of an inorganic filler is small (right figure). 本発明の一実施形態における多孔質層の表面の、無機フィラーの投影像を示す模式図である。It is a schematic diagram which shows the projected image of the inorganic filler of the surface of the porous layer in one Embodiment of this invention.
　本発明の一実施形態に関して以下に説明するが、本発明はこれに限定されるものではない。本発明は、以下に説明する各構成に限定されるものではなく、特許請求の範囲に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態に関しても本発明の技術的範囲に含まれる。なお、本明細書において特記しない限り、数値範囲を表す「Ａ～Ｂ」は、「Ａ以上、Ｂ以下」を意味する。 An embodiment of the present invention will be described below, but the present invention is not limited to this. The present invention is not limited to each configuration described below, various modifications are possible within the scope shown in the claims, and the technical means disclosed in different embodiments are appropriately combined. The obtained embodiments are also included in the technical scope of the present invention. Unless otherwise specified in the present specification, “A to B” representing a numerical range means “A or more and B or less”.
　本発明の一実施形態に係る非水電解液二次電池は、無機フィラーと樹脂とを含む多孔質層と、ＪＩＳ　Ｐ　８１１５（１９９４）に規定されたＭＩＴ試験機法に準拠し、荷重１Ｎ、折り曲げ角度４５°にて実施した耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１３０回以上である正極板と、前記耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１６５０回以上である負極板と、を備え、前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、１．４～４．０の範囲であり、前記多孔質層の、広角Ｘ線回折法により測定した、互いに直交する任意の回折面（hkl）、（abc）のピーク強度：Ｉ（hkl）およびＩ（abc）が下式（１）を満たし、下式（２）で算出されるピーク強度比の最大値の範囲が、１．５～３００の範囲である、非水電解液二次電池である。 A non-aqueous electrolyte secondary battery according to an embodiment of the present invention 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 of the negative electrode plate, the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0, the wide angle X of the porous layer. Peak intensities of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other measured by the line diffraction method: I (hkl) and I (abc) satisfy the following equation (1), and are calculated by the following equation (2). The range of the maximum value of the peak intensity ratio is 1 In the range of 5 to 300, a non-aqueous electrolyte secondary battery.
　Ｉ（hkl）　＞　Ｉ（abc）・・・（１）
　Ｉ（hkl）　／　Ｉ（abc）・・・（２）
　また、本発明の一実施形態に係る非水電解液二次電池は、後述するポリオレフィン多孔質フィルムをさらに備え得る。 I (hkl) > I (abc)・ ・ ・ (1)
I (hkl) / I (abc)・ ・ ・ (2)
The non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention may further include a polyolefin porous film described below.
　＜正極板＞
　本発明の一実施形態に係る非水電解液二次電池における正極板は、後述するように、耐折試験において測定される折り曲げ回数が特定の範囲であれば、その他の構成については特に限定されない。例えば、正極活物質層として、正極活物質、導電剤および結着剤を含む正極合剤を正極集電体上に担持したシート状の正極板が用いられる。なお、正極板は、正極集電体の両面上に正極合剤を担持してもよく、正極集電体の片面上に正極合剤を担持してもよい。 <Positive plate>
The positive electrode plate in the non-aqueous electrolyte secondary battery according to an embodiment of the present invention is not particularly limited in other configurations as long as the number of folding times measured in the folding endurance test is within a specific range, as described later. .. For example, as 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.
　前記正極活物質としては、例えば、リチウムイオンをドープ・脱ドープ可能な材料が挙げられる。当該材料としては、遷移金属酸化物が好ましい。遷移金属酸化物として、具体的には、例えば、Ｖ、Ｍｎ、Ｆｅ、ＣｏおよびＮｉ等の遷移金属を少なくとも１種類含んでいるリチウム複合酸化物が挙げられる。 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.
　前記導電剤としては、黒鉛（天然黒鉛、人造黒鉛）、コークス類、カーボンブラック、熱分解炭素類、炭素繊維、有機高分子化合物焼成体等の炭素質材料等が挙げられる。前記導電剤は、１種類のみを用いてもよく、２種類以上を組み合わせて用いてもよい。 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.
　前記結着剤としては、例えば、ポリフッ化ビニリデン、フッ化ビニリデンの共重合体、ポリテトラフルオロエチレン、テトラフルオロエチレン－ヘキサフルオロプロピレンの共重合体、テトラフルオロエチレン－パーフルオロアルキルビニルエーテルの共重合体、エチレン－テトラフルオロエチレンの共重合体、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－ヘキサフルオロプロピレン－テトラフルオロエチレンの共重合体、熱可塑性ポリイミド、ポリエチレン、およびポリプロピレン等の熱可塑性樹脂、アクリル樹脂、ならびにスチレンブタジエンゴムが挙げられる。なお、結着剤は、増粘剤としての機能も有している。 Examples of the binder 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.
　前記正極集電体としては、例えば、Ａｌ、Ｎｉ、ステンレス等の導電体が挙げられる。中でも、薄膜に加工し易く、安価であることから、Ａｌがより好ましい。 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.
　＜負極板＞
　本発明の一実施形態に係る非水電解液二次電池における負極板は、後述するように、耐折試験において測定される折り曲げ回数が特定の範囲であれば、その他の構成については特に限定されない。例えば、負極活物質層として、負極活物質を含む負極合剤を負極集電体上に担持したシート状の負極が用いられる。シート状の負極板には、好ましくは、前記導電剤および前記結着剤が含まれる。なお、負極板は、負極集電体の両面上に負極合剤を担持してもよく、負極集電体の片面上に負極合剤を担持してもよい。 <Negative electrode plate>
The negative electrode plate in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention is not particularly limited in other configurations as long as the number of folding times measured in the folding endurance test is within a specific range, as described later. .. For example, 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.
　前記負極活物質としては、例えば、リチウムイオンをドープ・脱ドープ可能な材料、リチウム金属またはリチウム合金等が挙げられる。当該材料としては、例えば、炭素質材料等が挙げられる。炭素質材料としては、黒鉛（天然黒鉛、人造黒鉛）、コークス類、カーボンブラック、および熱分解炭素類等が挙げられる。導電剤、結着剤としては、前記正極活物質層に含まれ得る導電剤、結着剤として記載したものを使用することができる。 The negative electrode active material includes, for example, a material capable of being doped / dedoped with lithium ions, lithium metal or a lithium alloy. Examples of the material include a carbonaceous material and the like. Examples of the carbonaceous material include graphite (natural graphite, artificial graphite), cokes, carbon black, and pyrolytic carbons. As 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.
　前記負極集電体としては、例えば、Ｃｕ、Ｎｉ、ステンレス等が挙げられ、特にリチウムイオン二次電池においてはリチウムと合金を作り難く、かつ薄膜に加工し易いことから、Ｃｕがより好ましい。 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.
　＜折り曲げ回数＞
　本発明の一実施形態に係る非水電解液二次電池が備える正極板および負極板は、ＪＩＳ
　Ｐ　８１１５（１９９４）に規定されたＭＩＴ試験機法に準拠して実施した耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が特定の範囲である。前記耐折試験は、荷重１Ｎ、折り曲げ角度４５°にて実施される。非水電解液二次電池では、充放電サイクルの過程で、電極活物質の膨張および収縮が起こり得る。前記耐折試験により測定された、電極活物質層が剥がれるまでの折り曲げ回数が多いほど、電極活物質層内部に含まれる成分（活物質、導電剤およびバインダー）同士の密着性、および、電極活物質層と集電体との密着性が維持されやすいことを表す。それゆえ、前記折り曲げ回数が多いほど、充放電サイクルの過程での非水電解液二次電池の劣化が抑制される。 <Number of folds>
The positive electrode plate and the negative electrode plate included in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention are JIS
In the folding endurance test carried out according to the MIT tester method defined in P 8115 (1994), the number of times of bending until the electrode active material layer is peeled off is within a specific range. 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, the electrode active material may expand and contract during the charge / discharge cycle. The more the number of bendings until the electrode active material layer is peeled off, measured by the folding endurance test, is that the components contained in the electrode active material layer (active material, conductive agent and binder) are closely attached to each other, and the electrode activity is large. It means that the adhesion between the material layer and the current collector is easily maintained. Therefore, the greater the number of times of bending, the more the deterioration of the non-aqueous electrolyte secondary battery during the charging / discharging cycle is suppressed.
　前記耐折試験において、正極板は、電極活物質層が剥がれるまでの折り曲げ回数が１３０回以上であり、１５０回以上であることがより好ましい。また、前記耐折試験において、負極板は、電極活物質層が剥がれるまでの折り曲げ回数が１６５０回以上であり、１８００回以上であることが好ましく、２０００回以上であることがより好ましい。 In the folding endurance test, the positive electrode plate has a bending frequency of 130 times or more before the electrode active material layer is peeled off, and more preferably 150 times or more. In addition, in the folding endurance test, 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.
　図１は、ＭＩＴ試験機法に用いられるＭＩＴ試験機の概略を示す模式図である。ｘ軸は水平方向を表し、ｙ軸は鉛直方向を表す。ＭＩＴ試験機法の概要を以下に説明する。試験片の長手方向の一端をばね荷重クランプで挟み、もう一端を折り曲げクランプで挟んで固定する。ばね荷重クランプは錘とつながっている。前記耐折試験では、この錘による荷重が１Ｎである。これにより試験片は、長手方向にテンションがかかった状態となる。この状態において、試験片の長手方向は鉛直方向と平行である。そして、折り曲げクランプを回転させることにより、試験片を折り曲げる。前記耐折試験では、この際の折り曲げ角度が４５°である。すなわち、試験片は左右に４５°に折り曲げられる。また、試験片を折り曲げる速度は、１７５往復／分である。 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. In the folding endurance test, the load by the weight is 1N. As a result, 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. Then, the test piece is bent by rotating the bending clamp. In the folding endurance test, 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.
　＜正極板および負極板の製造方法＞
　シート状の正極板の製造方法としては、例えば、正極活物質、導電剤および結着剤を正極集電体上で加圧成型する方法；適当な有機溶剤を用いて正極活物質、導電剤および結着剤をペースト状にした後、当該ペーストを正極集電体に塗工し、次いで、湿潤状態で、または乾燥した後に加圧することにより、正極集電体に固着する方法等が挙げられる。 <Method for producing positive electrode plate and negative electrode plate>
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.
　シート状の負極板の製造方法としては、例えば、負極活物質を負極集電体上で加圧成型する方法；適当な有機溶剤を用いて負極活物質をペースト状にした後、当該ペーストを負極集電体に塗工し、次いで、湿潤状態で、または乾燥した後に加圧することにより、負極集電体に固着する方法等が挙げられる。前記ペーストには、好ましくは前記導電剤および前記結着剤が含まれる。 Examples of the method for producing the sheet-shaped negative electrode plate include, for example, a method in which the negative electrode active material is pressure-molded on a negative electrode current collector; the negative electrode active material is made into a paste using an appropriate organic solvent, and then the paste is used as a negative electrode. Examples thereof include a method of applying to a current collector and then applying pressure to the negative electrode current collector in a wet state or after drying, and the like. The paste preferably contains the conductive agent and the binder.
　ここで、加圧を行う時間、圧力、または加圧方法等を調整することにより、上述の折り曲げ回数を制御することができる。加圧を行う時間は、１～３６００秒が好ましく、より好ましくは１～３００秒である。加圧は、正極板または負極板を拘束することによって行われてもよい。本明細書では、拘束による圧力を拘束圧とも称する。拘束圧は、０．０１～１０ＭＰａが好ましく、より好ましくは０．０１～５ＭＰａである。また、有機溶媒を用いて正極板または負極板を湿潤させた状態で加圧してもよい。これによって、電極活物質層内部に含まれる成分同士の密着性、および、電極活物質層と集電体との密着性が向上し得る。有機溶媒としては、例えば、カーボネート類、エーテル類、エステル類、ニトリル類、アミド類、カーバメート類および含硫黄化合物、ならびにこれらの有機溶媒にフッ素基が導入されてなる含フッ素有機溶媒等が挙げられる。 Here, the number of times of bending described above can be controlled by adjusting the time for applying pressure, the pressure, the pressing method, or the like. 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. In this specification, 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. Further, 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. Examples of 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. ..
　＜多孔質層＞
　本発明の一実施形態における多孔質層は、無機フィラーと樹脂とを含む多孔質層であって、当該多孔質層の表面（以下、「多孔質層表面」と称する場合がある）の無機フィラーの投影像のアスペクト比が、１．４～４．０の範囲であり、前記多孔質層の、広角Ｘ線回折法により測定した、互いに直交する任意の回折面（hkl）、（abc）のピーク強度：Ｉ（hkl）およびＩ（abc）が下式（１）を満たし、下式（２）で算出されるピーク強度比の最大値の範囲が、１．５～３００の範囲である。 <Porous layer>
The porous layer in one embodiment of the present invention is a porous layer containing an inorganic filler and a resin, and the inorganic filler on the surface of the porous layer (hereinafter, may be referred to as “porous layer surface”). Has an aspect ratio in the range of 1.4 to 4.0, and has an arbitrary diffraction plane (hkl), (abc) orthogonal to each other, measured by the wide-angle X-ray diffraction method, of the porous layer. Peak intensity: I (hkl) and I (abc) satisfy the following formula (1), and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300.
　Ｉ（hkl）　＞　Ｉ（abc）・・・（１）
　Ｉ（hkl）　／　Ｉ（abc）・・・（２）
　本発明の一実施形態において、多孔質層は、非水電解液二次電池を構成する部材として、ポリオレフィン多孔質フィルムと、前記正極板および前記負極板の少なくともいずれかとの間に配置され得る。また、前記多孔質層は、ポリオレフィン多孔質フィルムの片面または両面に形成され得る。或いは、前記多孔質層は、正極板および負極板の少なくともいずれか一方の活物質層上に形成され得る。或いは、前記多孔質層は、ポリオレフィン多孔質フィルムと、正極板および負極板の少なくともいずれか一方との間に、これらと接するように配置されてもよい。ポリオレフィン多孔質フィルムと正極板および負極板の少なくともいずれか一方との間に配置される多孔質層は１層でもよく２層以上であってもよい。多孔質層は、樹脂を含む絶縁性の多孔質層であることが好ましい。 I (hkl) > I (abc)・ ・ ・ (1)
I (hkl) / I (abc)・ ・ ・ (2)
In one embodiment of the present invention, 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 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. Alternatively, 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. Alternatively, 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.
　ポリオレフィン多孔質フィルムの片面に多孔質層が積層される場合には、当該多孔質層は、好ましくは、ポリオレフィン多孔質フィルムの面のうち、正極板と対向する面に積層される。より好ましくは、当該多孔質層は、ポリオレフィン多孔質フィルムの面のうち、正極板と接する面に積層される。 When 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 of the polyolefin porous film that is in contact with the positive electrode plate.
　前記「多孔質層の表面の、無機フィラーの投影像のアスペクト比」および前記「式（２）で算出されるピーク強度比の最大値」は、共に、多孔質層における無機フィラーの配向性を表す指標である。ここで、前記配向性が高い場合と、前記配向性が低い場合の、多孔質層における無機フィラーの態様の模式図を図１に示す。図１の左図が、無機フィラーを含む多孔質層における、フィラーの配向性が大きく異方性が高い場合の当該多孔質層の構造を表す模式図であり、図１の右図が、無機フィラーの配向性が小さく異方性が低い場合の当該多孔質層の構造を表す模式図である。 The “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “maximum value of the peak intensity ratio calculated by the formula (2)” both indicate the orientation of the inorganic filler in the porous layer. It is an index to represent. Here, FIG. 1 shows a schematic view of an embodiment of the inorganic filler in the porous layer when the orientation is high and when the orientation is low. The left diagram of FIG. 1 is a schematic diagram showing the structure of the porous layer containing an inorganic filler when the orientation of the filler is large and the anisotropy is high, and the right diagram of FIG. 1 is the inorganic layer. It is a schematic diagram showing the structure of the said porous layer in case the orientation of a filler is small and anisotropy is low.
　本発明の一実施形態における多孔質層は、無機フィラーと、樹脂とを含む。多孔質層は、内部に多数の細孔を有し、これら細孔が連結された構造となっており、一方の面から他方の面へと気体或いは液体が通過可能となった層である。また、本発明の一実施形態における多孔質層が後述する非水電解液二次電池用積層セパレータを構成する部材として使用される場合、前記多孔質層は、当該非水電解液二次電池用積層セパレータの最外層として、電極と接する層となり得る。 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. Further, when the porous layer in one embodiment of the present invention is used as a member constituting a laminated separator for a non-aqueous electrolyte secondary battery described later, the porous layer is for the non-aqueous electrolyte secondary battery. The outermost layer of the laminated separator can be a layer in contact with the electrode.
　本発明の一実施形態における多孔質層に含まれる樹脂は、電池の電解液に不溶であり、また、その電池の使用範囲において電気化学的に安定であることが好ましい。前記樹脂としては、具体的には、例えば、ポリオレフィン；（メタ）アクリレート系樹脂；含フッ素樹脂；ポリアミド系樹脂；ポリイミド系樹脂；ポリエステル系樹脂；ゴム類；融点またはガラス転移温度が１８０℃以上の樹脂；水溶性ポリマー；ポリカーボネート、ポリアセタール、ポリエーテルエーテルケトン等が挙げられる。 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. Specific examples of 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.
　上述の樹脂のうち、ポリオレフィン、ポリエステル系樹脂、（メタ）アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂および水溶性ポリマーが好ましい。 Among the above resins, polyolefins, polyester resins, (meth) acrylate resins, fluorine-containing resins, polyamide resins and water-soluble polymers are preferable.
　ポリオレフィンとしては、ポリエチレン、ポリプロピレン、ポリブテン、及びエチレン－プロピレン共重合体等が好ましい。 As the polyolefin, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer and the like are preferable.
　ポリアミド系樹脂としては、芳香族ポリアミドおよび全芳香族ポリアミドなどのアラミド樹脂が好ましい。 As the polyamide resin, aramid resins such as aromatic polyamide and wholly aromatic polyamide are preferable.
　アラミド樹脂としては、具体的には、例えば、ポリ（パラフェニレンテレフタルアミド）、ポリ（メタフェニレンイソフタルアミド）、ポリ（パラベンズアミド）、ポリ（メタベンズアミド）、ポリ（４，４’－ベンズアニリドテレフタルアミド）、ポリ（パラフェニレン－４，４’－ビフェニレンジカルボン酸アミド）、ポリ（メタフェニレン－４，４’－ビフェニレンジカルボン酸アミド）、ポリ（パラフェニレン－２，６－ナフタレンジカルボン酸アミド）、ポリ（メタフェニレン－２，６－ナフタレンジカルボン酸アミド）、ポリ（２－クロロパラフェニレンテレフタルアミド）、パラフェニレンテレフタルアミド／２，６－ジクロロパラフェニレンテレフタルアミド共重合体、メタフェニレンテレフタルアミド／２，６－ジクロロパラフェニレンテレフタルアミド共重合体等が挙げられる。このうち、ポリ（パラフェニレンテレフタルアミド）がより好ましい。 Specific examples of the aramid resin 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 terephthalamide) is more preferable.
　ポリエステル系樹脂としては、ポリアリレートなどの芳香族ポリエステルおよび液晶ポリエステルが好ましい。 As the polyester resin, aromatic polyester such as polyarylate and liquid crystal polyester are preferable.
　含フッ素樹脂としては、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン－ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン－パーフルオロアルキルビニルエーテル共重合体、フッ化ビニリデン－テトラフルオロエチレン共重合体、フッ化ビニリデン－トリフルオロエチレン共重合体、フッ化ビニリデン－トリクロロエチレン共重合体、フッ化ビニリデン－フッ化ビニル共重合体、フッ化ビニリデン－ヘキサフルオロプロピレン－テトラフルオロエチレン共重合体、およびエチレン－テトラフルオロエチレン共重合体等、並びに、前記含フッ素樹脂の中でもガラス転移温度が２３℃以下である含フッ素ゴムを挙げることができる。 Examples of the fluorine-containing resin 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 Among them, 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 above-mentioned fluorine-containing resins can be mentioned. That.
　ゴム類としては、スチレン－ブタジエン共重合体およびその水素化物、メタクリル酸エステル共重合体、アクリロニトリル－アクリル酸エステル共重合体、スチレン－アクリル酸エステル共重合体、エチレンプロピレンラバー、ポリ酢酸ビニル等を挙げることができる。 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.
　融点又はガラス転移温度が１８０℃以上の樹脂としては、ポリフェニレンエーテル、ポリスルホン、ポリエーテルスルホン、ポリフェニレンスルフィド、ポリエーテルイミド、ポリアミドイミド、ポリエーテルアミド等を挙げることができる。 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.
　水溶性ポリマーとしては、ポリビニルアルコール、ポリエチレングリコール、セルロースエーテル、アルギン酸ナトリウム、ポリアクリル酸、ポリアクリルアミド、ポリメタクリル酸等を挙げることができる。 Examples of water-soluble polymers include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, polymethacrylic acid and the like.
　なお、本発明の一実施形態における多孔質層に含まれる樹脂は、１種類でもよく、２種類以上の樹脂の混合物でもよい。 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.
　前記樹脂の中でも、多孔質層が正極に対向して配置される場合には、電池作動時に酸化劣化が生じたとしても非水電解液二次電池のレート特性および抵抗特性等の各種性能を維持し易いため、含フッ素樹脂が好ましい。 Among the resins, when the porous layer is arranged facing the positive electrode, various performances such as rate characteristics and resistance characteristics of the non-aqueous electrolyte secondary battery are maintained even if oxidative deterioration occurs during battery operation. A fluorine-containing resin is preferable because it is easy to do.
　本発明の一実施形態における多孔質層は、無機フィラーを含む。その含有量の下限値は、前記フィラーと、本発明の一実施形態における多孔質層を構成する樹脂との総重量に対して、５０重量％以上であることが好ましく、７０重量％以上であることがより好ましく、９０重量％以上であることがさらに好ましい。一方、本発明の一実施形態における多孔質層における、無機フィラーの含有量の上限値は、９９重量％以下であることが好ましく、９８重量％以下であることがより好ましい。前記フィラーの含有量が、５０重量％以上であることが耐熱性の観点から好ましく、前記フィラーの含有量が、９９重量％以下であることがフィラー間の密着性の観点から好ましい。無機フィラーを含有することで、前記多孔質層を含むセパレータの滑り性および耐熱性を向上し得る。無機フィラーとしては、非水電解液に安定であり、かつ、電気化学的に安定なフィラーであれば特に限定されない。電池の安全性を確保する観点からは、耐熱温度が１５０℃以上のフィラーが好ましい。 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. On the other hand, 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. By containing the inorganic filler, the slipperiness and heat resistance of the separator including the porous layer can be improved. 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.
　前記無機フィラーは、特に限定されないが、通常、絶縁性フィラーである。前記無機フィラーは、好ましくは、アルミニウム元素、亜鉛元素、カルシウム元素、ジルコニウム元素、ケイ素元素、マグネシウム元素、バリウム元素、およびホウ素元素からなる群から選ばれる少なくとも１種の元素を含む無機物であり、好ましくはアルミニウム元素を含む無機物である。また、無機フィラーは、好ましくは前記元素の酸化物を含む。 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. The inorganic filler preferably contains an oxide of the above element.
　具体的には、無機フィラーとして、チタン酸化物、アルミナ（Ａｌ２Ｏ３）、酸化亜鉛（ＺｎＯ）、酸化カルシウム（ＣａＯ）、酸化ジルコニア（ＺｒＯ２）、シリカ、マグネシア、酸化バリウム、酸化ホウ素、マイカ、ワラストナイト、アタパルジャイト、ベーマイト（アルミナ１水和物）などを挙げることができる。前記無機フィラーとしては、１種類のフィラーを単独で使用してもよく、２種類以上のフィラーを組み合わせて使用してもよい。 Specifically, as 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). As the inorganic filler, one kind of filler may be used alone, or two or more kinds of filler may be used in combination.
　本発明の一実施形態における多孔質層における無機フィラーは、アルミナおよび板状フィラーを含むことが好ましい。前記板状フィラーとしては、前記元素の酸化物のうち、例えば、酸化亜鉛（ＺｎＯ）、マイカおよびベーマイトからなる群より選ばれる１以上のフィラーを挙げることができる。 The inorganic filler in the porous layer in one embodiment of the present invention preferably contains alumina and a plate-like filler. Examples of the plate-like filler include one or more fillers selected from the group consisting of zinc oxide (ZnO), mica, and boehmite among oxides of the above elements.
　前記無機フィラーの体積平均粒子径は、良好な接着性と滑り性の確保、および積層体の成形性の観点から、０．０１μｍ～１０μｍの範囲であることが好ましい。その下限値としては０．０５μｍ以上がより好ましく、０．１μｍ以上がさらに好ましい。その上限値としては５μｍ以下がより好ましく、１μｍ以下がさらに好ましい。 The volume average particle size of the inorganic filler is preferably in the range of 0.01 μm to 10 μm from the viewpoint of ensuring good adhesiveness and slipperiness, and moldability of the laminate. The lower limit value is more preferably 0.05 μm or more, further preferably 0.1 μm or more. The upper limit value is more preferably 5 μm or less, further preferably 1 μm or less.
　前記無機フィラーの形状は、任意であり、特に限定されない。前記無機フィラーの形状は、粒子状であり得、例えば、球形状；楕円形状；板状；棒状；不定形状；繊維状；ピーナッツ状および／またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状；の何れでもよい。電池の短絡防止の観点から、前記無機フィラーは、板状の粒子、および／または、凝集していない一次粒子であることが好ましい。また、イオン透過の観点からは、前記無機フィラーの形状は、多孔質中の粒子が最密充填され難く、粒子間に空隙が形成され易い、瘤、へこみ、くびれ、***もしくは膨らみを有する、樹枝状、珊瑚状、もしくは房（ふさ）状などの不定形状；繊維状；ピーナッツ状および／またはテトラポット状のように単一粒子が熱融着した形状であることが好ましい。前記無機フィラーの形状は、ピーナッツ状および／またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状であることが特にさらに好ましい。 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. From the viewpoint of preventing a short circuit in the battery, the inorganic filler is preferably plate-like particles and / or non-aggregated primary particles. Further, from the viewpoint of ion permeation, 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 It is preferable that 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.
　フィラーは、多孔質層の表面に微細な凹凸を形成することで滑り性を向上させ得るものであるが、フィラーが板状の粒子および／または凝集していない一次粒子である場合には、フィラーによって多孔質層の表面に形成される凹凸がより微細になり、多孔質層と電極との接着性がより良好となる。 The filler can improve the slipperiness by forming fine irregularities on the surface of the porous layer, but when the filler is plate-like particles and / or primary particles which are not aggregated, the filler is As a result, the unevenness formed on the surface of the porous layer becomes finer, and the adhesiveness between the porous layer and the electrode becomes better.
　本発明の一実施形態における多孔質層に含まれる、無機フィラーを構成する前記元素の酸化物の酸素原子質量百分率は、１０％～５０％であることが好ましく、２０％～５０％であることがより好ましい。本明細書において、「酸素原子質量百分率」とは、前記元素の酸化物全体の総質量に対する、当該酸化物中の酸素原子の質量の比を百分率で表したものを意味する。例えば、酸化亜鉛の場合、亜鉛の原子量：６５．４、酸素の原子量：１６.０より酸化亜鉛（ＺｎＯ）の分子量が６５．４＋１６．０＝８１．４であることから、酸化亜鉛中の酸素原子質量百分率は１６．０/８１．４×１００＝２０（％）である。 In the embodiment of the present invention, the oxygen atom mass percentage of the oxide of the element forming the inorganic filler contained in the porous layer is preferably 10% to 50%, and preferably 20% to 50%. Is more preferable. In the present specification, “oxygen atom mass percentage” means a ratio of the mass of oxygen atoms in the oxide to the total mass of the oxide of the element, which is expressed as a percentage. For example, in the case of zinc oxide, since the atomic weight of zinc is 65.4 and the atomic weight of oxygen is 16.0, the molecular weight of zinc oxide (ZnO) is 65.4 + 16.0 = 81.4. The atomic mass percentage is 16.0 / 81.4 × 100 = 20 (%).
　前記元素の酸化物の酸素原子質量百分率が上述の範囲であれば、後述する多孔質層の製造方法にて使用する塗工液中の溶媒または分散媒と、前記無機フィラーとの親和性を好適に保ち、前記無機フィラー間を適切な距離に保つことができる。これにより、塗工液の分散性を良好にすることができ、その結果、「多孔質層の表面の、無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を適切な規定範囲に制御することができる。 If the oxygen atomic mass percentage of the oxide of the element is in the above range, 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 preferable. It is possible to maintain a proper distance between the inorganic fillers. Thereby, the dispersibility of the coating liquid can be improved, and as a result, the "aspect ratio of the projected image of the inorganic filler on the surface of the porous layer" and the "orientation degree of the porous layer" can be defined appropriately. The range can be controlled.
　本発明の一実施形態における多孔質層に含まれる、無機フィラー自体のアスペクト比は、無機フィラーを平面上に配置した状態で、配置面の鉛直上方から観察したＳＥＭ像において、厚み方向に重なりあわない粒子１００個の、短軸の長さと長軸の長さとの比の平均値として表される。なお、本明細書において、長軸の長さを長軸径、短軸の長さを短軸径とも称する。
前記無機フィラー自体のアスペクト比は、１～１０であることが好ましく、
１．１～８であることがより好ましく、１．２～５であることがさらに好ましい。無機フィラー自体のアスペクト比が上述の範囲であることによって、後述する方法にて本発明の一実施形態における多孔質層を形成した際に、得られる多孔質層において、当該フィラーの配向性や、多孔質層表面におけるフィラーの分布の均一性を好ましい範囲に制御することができる。 The aspect ratio of the inorganic filler itself, which is contained in the porous layer in the embodiment of the present invention, is a state in which the inorganic filler is arranged on a plane, in an SEM image observed from vertically above the arrangement surface, overlapping in the thickness direction. It is expressed as the average value of the ratio of the length of the short axis to the length of the long axis of 100 particles that are not present. In the present specification, the length of the major axis is also referred to as the major axis diameter, and the length of the minor axis is also referred to as the minor axis diameter.
The aspect ratio of the inorganic filler itself is preferably 1 to 10,
It is more preferably 1.1 to 8, and even more preferably 1.2 to 5. By the aspect ratio of the inorganic filler itself is in the above range, when the porous layer in one embodiment of the present invention is formed by the method described below, in the resulting porous layer, the orientation of the filler, The uniformity of the distribution of the filler on the surface of the porous layer can be controlled within a preferable range.
　本発明の一実施形態における多孔質層は、上述の無機フィラーおよび樹脂以外のその他の成分を含んでいてもよい。前記その他の成分としては、例えば、界面活性剤、ワックス、バインダー樹脂などを挙げることができる。また、前記その他の成分の含有量は、多孔質層全体の重量に対して、０重量％～５０重量％であることが好ましい。 The porous layer in one embodiment of the present invention may contain other components than the above-mentioned inorganic filler and resin. Examples of 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.
　本発明の一実施形態における多孔質層の平均膜厚は、電極との接着性および高エネルギー密度を確保する観点から、多孔質層一層当たり、０．５μｍ～１０μｍの範囲であることが好ましく、１μｍ～５μｍの範囲であることがより好ましい。 The average film thickness of the porous layer in one embodiment of the present invention is preferably in the range of 0.5 μm to 10 μm 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 μm to 5 μm.
　多孔質層の単位面積当たりの目付は、多孔質層の強度、膜厚、重量およびハンドリング性を考慮して適宜決定することができる。多孔質層の単位面積当たりの目付は、多孔質層一層当たり、０．５～２０ｇ／ｍ２であることが好ましく、０．５～１０ｇ／ｍ２であることがより好ましい。 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.
　多孔質層の単位面積当たりの目付をこれらの数値範囲とすることにより、非水電解液二次電池の重量エネルギー密度および体積エネルギー密度を高くすることができる。多孔質層の目付が前記範囲を超える場合には、非水電解液二次電池が重くなる傾向がある。 By setting the basis weight per unit area of the porous layer within these numerical ranges, the weight energy density and volume energy density of the non-aqueous electrolyte secondary battery can be increased. When the basis weight of the porous layer exceeds the above range, the non-aqueous electrolyte secondary battery tends to be heavy.
　多孔質層の空隙率は、充分なイオン透過性を得ることができるように、２０～９０体積％であることが好ましく、３０～８０体積％であることがより好ましい。また、多孔質層が有する細孔の孔径は、１．０μｍ以下であることが好ましく、０．５μｍ以下であることがより好ましい。細孔の孔径をこれらのサイズとすることにより、非水電解液二次電池は、充分なイオン透過性を得ることができる。 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 μm or less, more preferably 0.5 μm or less. By setting the pore diameters to these sizes, the non-aqueous electrolyte secondary battery can obtain sufficient ion permeability.
　＜多孔質層表面の無機フィラーの投影像のアスペクト比＞
　本発明の一実施形態における多孔質層は、当該多孔質層表面の、無機フィラーの投影像のアスペクト比が、１．４～４．０の範囲であり、１．５～２．３の範囲であることが好ましい。ここで、前記アスペクト比は、走査型電子顕微鏡（ＳＥＭ）を使用して、多孔質層の真上、すなわち鉛直上方から、その表面の電子顕微鏡写真であるＳＥＭ画像を撮影し、その写真から無機フィラーの投影像を作成し、当該無機フィラーの投影像の長軸の長さ／短軸の長さの比率を算出することによって求められる値である。すなわち、前記アスペクト比とは、多孔質層の表面における無機フィラーを、多孔質層の真上方向から観測した場合に観測される当該無機フィラーの形状を示す。 <Aspect ratio of projected image of inorganic filler on porous layer surface>
In the porous layer in one embodiment of the present invention, the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0 and in the range of 1.5 to 2.3. Is preferred. Here, for the aspect ratio, a scanning electron microscope (SEM) is used to take an SEM image, which is an electron micrograph of the surface, immediately above the porous layer, that is, from above the vertical direction. It is a value obtained by creating a projected image of the filler and calculating the ratio of the major axis length / minor axis length of the projected image of the inorganic filler. That is, the aspect ratio refers to the shape of the inorganic filler observed when the inorganic filler on the surface of the porous layer is observed from directly above the porous layer.
　上述の多孔質層表面のＳＥＭ画像から作成される無機フィラーの投影像の模式図を図３に示す。 Fig. 3 shows a schematic diagram of the projected image of the inorganic filler created from the SEM image of the surface of the porous layer described above.
　前記アスペクト比の具体的な測定法としては、例えば、以下の（１）～（４）に示す工程からなる方法が挙げられる。なお、多孔質層の「表面」とは、多孔質層の真上からＳＥＭによって観察可能な多孔質層の面をいう。
（１）多孔質層を基材上に積層させてなる積層体において、当該積層体の多孔質側の真上から日本電子製　電界放出形走査電子顕微鏡ＪＳＭ－７６００Ｆを用いて加速電圧５ｋＶでＳＥＭ表面観察（反射電子像）を行い、ＳＥＭ画像を得る工程。
（２）工程（１）にて得られたＳＥＭ画像上にＯＨＰフィルムを載せ、当該ＳＥＭ画像に写っている無機フィラーの粒子の輪郭に沿って敷き写した投影像を作成し、該投影像をデジタルスチルカメラにより撮影する工程。
（３）工程（２）にて得られた写真のデータをコンピュータに取り込み、アメリカ国立衛生研究所（ＮＩＨ：Ｎａｔｉｏｎａｌ Ｉｎｓｔｉｔｕｅｓ ｏｆ Ｈｅａｌｔｈ）が発行する画像解析のフリーソフトＩＭＡＧＥＪを用いて、前記フィラー粒子１００個の各々のアスペクト比を算出する工程。なお、ここで前記フィラー粒子を１粒子ずつ楕円形に近似させ、長軸径と短軸径を算出し、長軸径を短軸径で除した値をアスペクト比とする。
（４）工程（３）にて得られたそれぞれの粒子の投影像のアスペクト比の平均値を算出し、その値を多孔質層表面の無機フィラーの投影像のアスペクト比とする工程。 As a specific measuring method of the aspect ratio, for example, a method including the following steps (1) to (4) can be mentioned. The “surface” of the porous layer means the surface of the porous layer that can be observed by SEM from directly above the porous layer.
(1) In a laminated body in which a porous layer is laminated on a substrate, an SEM at an accelerating voltage of 5 kV is used from directly above the porous side of the laminated body by using a field emission scanning electron microscope JSM-7600F manufactured by JEOL Ltd. A step of observing the surface (reflected electron image) to obtain an SEM image.
(2) An OHP film is placed on the SEM image obtained in the step (1), a projection image laid along the contour of the particles of the inorganic filler shown in the SEM image is created, and the projection image is obtained. The process of shooting with a digital still camera.
(3) The photographic data obtained in the step (2) is loaded into a computer, and the filler particles 100 are filled with the image analysis free software IMAGEJ issued by the National Institutes of Health (NIH). Calculating the aspect ratio of each of the pieces. Here, each of the filler particles is approximated to an ellipse one by one, the major axis diameter and the minor axis diameter are calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter is defined as an aspect ratio.
(4) A step of calculating the average value of the aspect ratios of the projected images of the respective particles obtained in the step (3), and using that value as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer.
　前記多孔質層表面の無機フィラーの投影像のアスペクト比は、多孔質層、特にその表面における無機フィラーの分布の均一性を示す指標である。前記アスペクト比が１に近いということは、多孔質層表面の構成材の形状ならびに分布が均一であり、密に充填されやすい。一方、前記アスペクト比が大きいことは、多孔質層の表面構造における構成成分の配置が不均一になり、結果として、多孔質層表面開口部の形状並びに分布の均一性が低下することを示す。 The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is an index showing the uniformity of the distribution of the inorganic filler on the porous layer, especially on the surface thereof. When the aspect ratio is close to 1, the shape and distribution of the constituent material on the surface of the porous layer are uniform, and it is easy to be densely packed. On the other hand, when the aspect ratio is large, the arrangement of the constituent components in the surface structure of the porous layer becomes non-uniform, and as a result, the uniformity of the shape and distribution of the openings of the surface of the porous layer deteriorates.
　前記アスペクト比が４．０より大きい場合には、多孔質層、特にその表面開口部の形状並びに分布の均一性が、過度に低下するため、前記多孔質層を組み込んだ非水電解液二次電池において、電池作動時の多孔質層の電解液受入能力が低下する箇所が生じる。その結果、当該非水電解液二次電池のレート特性が低下すると考えられる。一方、前記アスペクト比が１．４未満である場合には、多孔質層、特にその表面の無機フィラーの分布が、過度に均一化された構造となり、結果として多孔質層の表面開口部面積が小さくなるため、前記多孔質層を組み込んだ非水電解液二次電池において、電池作動時の多孔質層の電解液受入能力が低下する。その結果、当該非水電解液二次電池の電池レート特性が低下すると考えられる。 If the aspect ratio is greater than 4.0, the uniformity of the shape and distribution of the porous layer, especially the surface openings thereof, is excessively reduced, so that a non-aqueous electrolyte secondary electrode incorporating the porous layer is used. In the battery, there is a portion where the ability of the porous layer to receive the electrolytic solution during the operation of the battery is lowered. As a result, it is considered that the rate characteristics of the non-aqueous electrolyte secondary battery are deteriorated. On the other hand, when the aspect ratio is less than 1.4, the porous layer, in particular, the distribution of the inorganic filler on the surface thereof has an excessively uniform structure, and as a result, the surface opening area of the porous layer is small. Therefore, in the non-aqueous electrolyte secondary battery incorporating the porous layer, the ability of the porous layer to receive the electrolytic solution at the time of battery operation decreases. As a result, it is considered that the battery rate characteristic of the non-aqueous electrolyte secondary battery is deteriorated.
　＜多孔質層の配向度＞
　本発明の一実施形態における多孔質層は、広角Ｘ線回折法により測定した、当該多孔質層における互いに直交する任意の回折面（hkl）、（abc）のピーク強度：Ｉ（hkl）およびＩ（abc）が下式（１）を満たし、かつ、下式（２）で算出されるピーク強度比の最大値の範囲が、１．５～３００の範囲であり、１．５～２５０の範囲であることがより好ましい。 <Orientation of porous layer>
The porous layer according to one embodiment of the present invention has a peak intensity of arbitrary diffraction planes (hkl), (abc) orthogonal to each other in the porous layer measured by a wide-angle X-ray diffraction method: I (hkl) and I (Abc) satisfies the following formula (1), and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300 and in the range of 1.5 to 250. Is more preferable.
　Ｉ（hkl）　＞　Ｉ（abc）・・・（１）、
　Ｉ（hkl）　／　Ｉ（abc）・・・（２）
　以下、本明細書において、前記式（２）で算出されるピーク強度比の最大値を、「多孔質層の配向度」とも称する。 I (hkl) > I (abc) ... (1),
I (hkl) / I (abc)・ ・ ・ (2)
Hereinafter, in the present specification, the maximum value of the peak intensity ratio calculated by the formula (2) is also referred to as “the degree of orientation of the porous layer”.
　前記ピーク強度Ｉ（hkl）およびＩ（abc）、並びに、ピーク強度比Ｉ（hkl）　／　Ｉ（abc）を測定する方法は、特に限定されないが、例えば、以下の（１）～（３）に示す工程からなる方法を挙げることができる。
（１）多孔質層を基材上に積層させてなる積層体（積層多孔質フィルム）を２ｃｍ角に切り取り、測定用サンプルを作製する工程。
（２）工程（１）にて得られた測定用サンプルを、当該サンプルにおける多孔質層側を測定面として、Ａｌ製ホルダーに取り付け広角Ｘ線回折法（２θ－θスキャン法）でＸ線プロファイルを測定する工程。なお、前記Ｘ線プロファイルを測定する装置および測定条件は、特に限定されないが、例えば、装置として理学電機社製ＲＵ－２００Ｒ（回転対陰極型）を使用し、Ｘ線源にＣｕＫα線を用い、出力は５０ＫＶ－２００ｍＡ、スキャン速度２°／ｍｉｎにて測定する方法が挙げられる。
（３）工程（２）にて得られるＸ線プロファイルに基づき、多孔質層の広角Ｘ線回折測定における、お互いに直交する任意の回折面（ｈｋｌ）、（ａｂｃ）のピーク強度　Ｉ（ｈｋｌ）およびＩ（ａｂｃ）が前記式（１）を満たす場合に、前記式（２）で算出されるピーク強度比を算出し、そのピーク強度比の最大値、すなわち多孔質層の配向度を算出する工程。 The method for measuring the peak intensities I (hkl) and I (abc) and the peak intensity ratio I (hkl) / I (abc) is not particularly limited. For example, the following (1) to (3) are used. A method comprising the steps shown can be mentioned.
(1) A step of preparing a measurement sample by cutting a 2 cm square laminate (laminated porous film) obtained by laminating a porous layer on a substrate.
(2) The measurement sample obtained in step (1) is mounted on an Al holder with the porous layer side of the sample as the measurement surface, and an X-ray profile is obtained by a wide-angle X-ray diffraction method (2θ-θ scan method). Measuring step. The device for measuring the X-ray profile and the measurement conditions are not particularly limited. The output may be measured at 50 KV-200 mA and a scan speed of 2 ° / min.
(3) Based on the X-ray profile obtained in step (2), peak intensity I (hkl) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in wide-angle X-ray diffraction measurement of the porous layer And I (abc) satisfy the equation (1), the peak intensity ratio calculated by the equation (2) is calculated, and the maximum value of the peak intensity ratio, that is, the degree of orientation of the porous layer is calculated. Process.
　なお、多孔質層の配向度の算出において、互いに直交する回折面を用いることにより、基材面に対して水平方向の向きと、法線方向の向きとの両方が決定されることが重要である。 In the calculation of the degree of orientation of the porous layer, it is important to determine both the orientation in the horizontal direction and the orientation in the normal direction with respect to the substrate surface by using the diffractive surfaces orthogonal to each other. is there.
　前記式（２）にて示されるピーク強度比の最大値は、多孔質層内部の配向度を示す指標である。前記式（２）にて示されるピーク強度比が小さいことは、多孔質層の内部構造における配向度が低いことを示し、前記式（２）にて示されるピーク強度比が大きいことは、多孔質層の内部構造における配向度が高いことを示す。 The maximum value of the peak intensity ratio shown by the above formula (2) is an index showing the degree of orientation inside the porous layer. A small peak intensity ratio represented by the formula (2) means that the degree of orientation in the internal structure of the porous layer is low, and a large peak intensity ratio represented by the formula (2) means that It shows that the internal structure of the texture layer has a high degree of orientation.
　前記式（２）にて示されるピーク強度比の最大値が３００より大きい場合には、多孔質層内部構造の異方性が過度に高い構造となり、多孔質層内部のイオン透過流路長が長くなる。その結果、前記多孔質層を組み込んだ非水電解液二次電池において、多孔質層のイオン透過抵抗が増加し、当該非水電解液二次電池の電池レート特性が低下すると考えられる。 When the maximum value of the peak intensity ratio represented by the formula (2) is larger than 300, the anisotropy of the internal structure of the porous layer becomes excessively high, and the ion permeation flow channel length inside the porous layer is increased. become longer. As a result, in the non-aqueous electrolyte secondary battery incorporating the porous layer, it is considered that the ion permeation resistance of the porous layer increases and the battery rate characteristics of the non-aqueous electrolyte secondary battery deteriorate.
　一方、前記式（２）にて示されるピーク強度比の最大値が１．５未満である場合には、１．５以上のピーク強度比を有する多孔質層を用いたケースに比べて、前記多孔質層を組み込んだ非水電解液二次電池において、電極から供給されるイオンを高速で透過させる。その為、電極からのイオン供給が律速となり（つまり、電極表面でイオンが枯渇する）、電池作動電流値条件である限界電流が小さくなる。その結果として、当該非水電解液二次電池の電池レート特性が低下すると考えられる。 On the other hand, when the maximum value of the peak intensity ratio represented by the above formula (2) is less than 1.5, compared to the case where the porous layer having the peak intensity ratio of 1.5 or more is used, In a non-aqueous electrolyte secondary battery incorporating a porous layer, the ions supplied from the electrodes are permeated at high speed. Therefore, the supply of ions from the electrode becomes rate-determining (that is, the ions are depleted on the electrode surface), and the limiting current, which is the battery operating current value condition, becomes small. As a result, it is considered that the battery rate characteristic of the non-aqueous electrolyte secondary battery is deteriorated.
　＜多孔質層の製造方法＞
　本発明の一実施形態における多孔質層の製造方法としては、特に限定されないが、例えば、基材上に、以下に示す工程（１）～（３）の何れかの１つの工程を用いて、前記無機フィラーと、前記樹脂とを含む多孔質層を形成する方法を挙げることができる。以下に示す工程（２）および工程（３）では、前記樹脂を析出させた後にさらに乾燥させ、溶媒を除去することによって、多孔質層が製造され得る。工程（１）～（３）における塗工液は、前記無機フィラーが分散しており、かつ、前記樹脂が溶解している状態であってもよい。なお、前記溶媒は、樹脂を溶解させる溶媒であるとともに、樹脂または無機フィラーを分散させる分散媒であるとも言える。 <Method for producing porous layer>
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. In steps (2) and (3) shown below, a 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.
　（１）前記無機フィラーおよび前記樹脂を含む塗工液を、基材上に塗工し、前記塗工液中の溶媒を乾燥除去することによって多孔質層を形成させる工程。 (1) A step of forming a porous layer by applying a coating liquid containing the inorganic filler and the resin onto a substrate and drying and removing the solvent in the coating liquid.
　（２）前記無機フィラーおよび前記樹脂を含む塗工液を、前記基材の表面に塗工した後、その基材を前記樹脂に対して貧溶媒である、析出溶媒に浸漬することによって、前記樹脂を析出させ、多孔質層を形成する工程。 (2) 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.
　（３）前記無機フィラーおよび前記樹脂を含む塗工液を、前記基材の表面に塗工した後、低沸点有機酸を用いて、前記塗工液の液性を酸性にすることによって、前記樹脂を析出させ、多孔質層を形成する工程。 (3) After coating a coating liquid containing the inorganic filler and the resin on the surface of the base material, 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.
　前記基材には、後述するポリオレフィン多孔質フィルムの他に、その他のフィルム、正極および負極などを用いることができる。 In addition to the polyolefin porous film described below, other films, a positive electrode, a negative electrode, and the like can be used as the base material.
　前記溶媒は基材に悪影響を及ぼさず、前記樹脂を均一かつ安定に溶解し、前記無機フィラーを均一かつ安定に分散させる溶媒であることが好ましい。前記溶媒としては、例えば、Ｎ－メチル－２－ピロリドン、Ｎ，Ｎ－ジメチルアセトアミド、Ｎ，Ｎ－ジメチルホルムアミド、アセトンおよび水等が挙げられる。 Preferably, the solvent does not adversely affect the base material, dissolves the resin uniformly and stably, and disperses the inorganic filler uniformly and stably. Examples of the solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, acetone and water.
　前記析出溶媒としては、例えば、イソプロピルアルコールまたはｔ－ブチルアルコールを用いることが好ましい。 As the deposition solvent, for example, isopropyl alcohol or t-butyl alcohol is preferably used.
　前記工程（３）において、低沸点有機酸としては、例えば、パラトルエンスルホン酸、酢酸等を使用することができる。 In the step (3), as the low boiling point organic acid, for example, paratoluenesulfonic acid, acetic acid, etc. can be used.
　また、本発明の一実施形態における多孔質層の配向性、すなわち、「多孔質層表面の無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を制御する方法として、以下に示すように、多孔質層の製造に使用する、前記無機フィラーおよび前記樹脂を含む塗工液の固形分濃度、並びに、前記塗工液を基材上に塗工する際の塗工せん断速度を調節することを挙げることができる。 In addition, as a method of controlling the orientation of the porous layer in one embodiment of the present invention, that is, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”, As shown, used in the production of the porous layer, the solid content concentration of the coating liquid containing the inorganic filler and the resin, and the coating shear rate when coating the coating liquid on the substrate The adjustment can be mentioned.
　前記塗工液の好適な固形分濃度は、フィラーの種類などによって変化し得るが、一般には、２０重量％より大きく４０重量％以下であることが好ましい。前記固形分濃度が上述の範囲であることは、前記塗工液の粘度を適切に保ち、その結果、「多孔質層表面の無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を上述の好適な範囲に制御することができるため好ましい。 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. That the solid content concentration is in the above range, the viscosity of the coating liquid is appropriately maintained, and as a result, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”. Is preferable because it can be controlled within the above-mentioned preferable range.
　前記塗工液を基材上に塗工する際の塗工せん断速度は、フィラーの種類などによって変化し得るが、一般には、２（１／ｓ）以上であることが好ましく、４（１／ｓ）～５０（１／ｓ）であることがより好ましい。 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).
　ここで、例えば、前記無機フィラーとして、ピーナッツ状および／またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状、球形状、楕円形状、板状、棒状、または、不定形状の形状を有する無機フィラーを用いた場合、前記塗工せん断速度を大きくすると、高せん断力が無機フィラーにかかるため、異方性が高くなる傾向がある。一方、前記塗工せん断速度を小さくするとせん断力が無機フィラーにかからないため、等方的に配向する傾向がある。 Here, for example, as 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. When an inorganic filler having the above-mentioned shape is used, if the coating shear rate is increased, a high shearing force is applied to the inorganic filler, so that the anisotropy tends to increase. On the other hand, when 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.
　一方、前記無機フィラーが繊維径の長いワラストナイトのような長繊維径無機フィラーである場合には、前記塗工せん断速度を大きくすると、長繊維どうしが絡み合う、あるいはドクターブレードの刃に長繊維がひっかかるためばらばらの配向になり、異方性が低くなる傾向がある。一方、前記塗工せん断速度を小さくすると、長繊維が、互いに絡み合うことがなく、ドクターブレードの刃にひっかからないので、配向しやすくなり、異方性は高くなる傾向がある。 On the other hand, when the inorganic filler is a long fiber diameter inorganic filler such as long wollastonite having a large fiber diameter, when 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. On the other hand, when 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.
　＜ポリオレフィン多孔質フィルム＞
　本発明の一実施形態における非水電解液二次電池は、ポリオレフィン多孔質フィルムを備えていてもよい。以下では、ポリオレフィン多孔質フィルムを単に「多孔質フィルム」と称することがある。前記多孔質フィルムは、ポリオレフィン系樹脂を主成分とし、その内部に連結した細孔を多数有しており、一方の面から他方の面に気体および液体を通過させることが可能となっている。前記多孔質フィルムは、単独で非水電解液二次電池用セパレータとなり得る。また、上述の多孔質層が積層された非水電解液二次電池用積層セパレータにおける多孔質基材ともなり得る。 <Polyolefin porous film>
The non-aqueous electrolyte secondary battery in one embodiment of the present invention may include a polyolefin porous film. Below, 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.
　前記ポリオレフィン多孔質フィルムの少なくとも一方の面上に、前記多孔質層が積層されてなる積層体を、本明細書において、「非水電解液二次電池用積層セパレータ」または「積層セパレータ」とも称する。また、本発明の一実施形態における非水電解液二次電池用セパレータは、ポリオレフィン多孔質フィルムの他に、接着層、耐熱層、保護層等のその他の層をさらに備えていてもよい。 On at least one surface of the polyolefin porous film, 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" .. Further, the separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention 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.
　多孔質フィルムに占めるポリオレフィンの割合は、多孔質フィルム全体の５０体積％以上であり、９０体積％以上であることがより好ましく、９５体積％以上であることがさらに好ましい。また、前記ポリオレフィンには、重量平均分子量が５×１０５～１５×１０６の高分子量成分が含まれていることがより好ましい。特に、ポリオレフィンに重量平均分子量が１００万以上の高分子量成分が含まれていると、非水電解液二次電池用セパレータの強度が向上するのでより好ましい。 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.
　熱可塑性樹脂である前記ポリオレフィンとしては、具体的には、例えば、エチレン、プロピレン、１－ブテン、４－メチル－１－ペンテンおよび１－ヘキセン等の単量体を重合してなる、単独重合体または共重合体が挙げられる。前記単独重合体としては、例えばポリエチレン、ポリプロピレン、ポリブテンを挙げることができる。また、前記共重合体としては、例えばエチレン－プロピレン共重合体を挙げることができる。 The polyolefin, which is a thermoplastic resin, is specifically a homopolymer obtained by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene and 1-hexene. Alternatively, a copolymer may be used. Examples of the homopolymer include polyethylene, polypropylene and polybutene. Examples of the copolymer include ethylene-propylene copolymer.
　このうち、過大電流が流れることをより低温で阻止することができるため、ポリエチレンがより好ましい。なお、この過大電流が流れることを阻止することをシャットダウンともいう。前記ポリエチレンとしては、低密度ポリエチレン、高密度ポリエチレン、線状ポリエチレン（エチレン－α－オレフィン共重合体）、重量平均分子量が１００万以上の超高分子量ポリエチレン等が挙げられる。このうち、重量平均分子量が１００万以上の超高分子量ポリエチレンがさらに好ましい。 Among these, 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. Examples of the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene-α-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.
　多孔質フィルムの膜厚は、４～４０μｍであることが好ましく、５～３０μｍであることがより好ましく、６～１５μｍであることがさらに好ましい。 The thickness of the porous film is preferably 4 to 40 μm, more preferably 5 to 30 μm, and further preferably 6 to 15 μm.
　多孔質フィルムの単位面積当たりの目付は、強度、膜厚、重量およびハンドリング性を考慮して適宜決定することができる。ただし、非水電解液二次電池の重量エネルギー密度および体積エネルギー密度を高くすることができるように、前記目付は、４～２０ｇ／ｍ２であることが好ましく、４～１２ｇ／ｍ２であることがより好ましく、５～１０ｇ／ｍ２であることがさらに好ましい。 The basis weight per unit area of the porous film can be appropriately determined in consideration of strength, film thickness, weight and handleability. However, 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 .
　多孔質フィルムの透気度は、ガーレ値で３０～５００ｓｅｃ／１００ｍＬであることが好ましく、５０～３００ｓｅｃ／１００ｍＬであることがより好ましい。多孔質フィルムが前記透気度を有することにより、充分なイオン透過性を得ることができる。多孔質フィルムに上述の多孔質層を積層させた非水電解液二次電池用積層セパレータの透気度は、ガーレ値で３０～１０００ｓｅｃ／１００ｍＬであることが好ましく、５０～８００ｓｅｃ／１００ｍＬであることがより好ましい。非水電解液二次電池用積層セパレータは、前記透気度を有することにより、非水電解液二次電池において、充分なイオン透過性を得ることができる。 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. When the porous film has the above-mentioned air permeability, sufficient ion permeability can be obtained. 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.
　多孔質フィルムの空隙率は、電解液の保持量を高めると共に、過大電流が流れることをより低温で確実に阻止する機能を得ることができるように、２０～８０体積％であることが好ましく、３０～７５体積％であることがより好ましい。また、多孔質フィルムが有する細孔の孔径は、充分なイオン透過性を得ることができ、かつ、正極および負極への粒子の入り込みを防止することができるように、０．３μｍ以下であることが好ましく、０．１４μｍ以下であることがより好ましい。 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 μm or less so that sufficient ion permeability can be obtained and particles can be prevented from entering the positive electrode and the negative electrode. Is preferable, and 0.14 μm or less is more preferable.
　＜ポリオレフィン多孔質フィルムの製造方法＞
　前記ポリオレフィン多孔質フィルムの製造方法は特に限定されるものではない。例えば、ポリオレフィン系樹脂と、無機充填剤および可塑剤等の孔形成剤と、任意で酸化防止剤等を混練した後に押し出すことにより、シート状のポリオレフィン樹脂組成物を作製する。適当な溶媒にて当該孔形成剤を当該シート状のポリオレフィン樹脂組成物から除去した後、当該孔形成剤が除去されたポリオレフィン樹脂組成物を延伸することにより、ポリオレフィン多孔質フィルムを製造することができる。 <Method for producing polyolefin porous film>
The method for producing the polyolefin porous film is not particularly limited. For example, 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 mixture. 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.
　前記無機充填剤としては、特に限定されるものではなく、無機フィラー、具体的には炭酸カルシウム等が挙げられる。前記可塑剤としては、特に限定されるものではなく、流動パラフィン等の低分子量の炭化水素が挙げられる。 The inorganic filler is not particularly limited, and examples thereof include inorganic fillers, specifically calcium carbonate. The plasticizer is not particularly limited, and examples thereof include low molecular weight hydrocarbons such as liquid paraffin.
　具体的には、以下に示すような工程を含む方法を挙げることができる。
（Ａ）超高分子量ポリエチレンと、重量平均分子量１万以下の低分子量ポリエチレンと、炭酸カルシウムまたは可塑剤等の孔形成剤と、酸化防止剤とを混練してポリオレフィン樹脂組成物を得る工程、
（Ｂ）得られたポリオレフィン樹脂組成物を一対の圧延ローラで圧延し、速度比を変えた巻き取りローラで引っ張りながら段階的に冷却し、シートを成形する工程、
（Ｃ）得られたシートの中から適当な溶媒にて孔形成剤を除去する工程、
（Ｄ）孔形成剤が除去されたシートを適当な延伸倍率にて延伸する工程。 Specifically, 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.
　［非水電解液二次電池用積層セパレータの製造方法］
　本発明の一実施形態における非水電解液二次電池用積層セパレータの製造方法としては、例えば、上述の「多孔質層の製造方法」において、前記塗工液を塗布する基材として、前記ポリオレフィン多孔質フィルムを使用する方法を挙げることができる。 [Method for producing laminated separator for non-aqueous electrolyte secondary battery]
As a method for producing a laminated separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, the polyolefin The method using a porous film can be mentioned.
　＜非水電解液＞
　本発明の一実施形態に係る非水電解液二次電池に含まれ得る非水電解液は、一般に非水電解液二次電池に使用される非水電解液であれば特に限定されない。前記非水電解液としては、例えば、リチウム塩を有機溶媒に溶解してなる非水電解液を用いることができる。リチウム塩としては、例えば、ＬｉＣｌＯ４、ＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＣ（ＣＦ３ＳＯ２）３、Ｌｉ２Ｂ１０Ｃｌ１０、低級脂肪族カルボン酸リチウム塩およびＬｉＡｌＣｌ４等が挙げられる。前記リチウム塩は、１種類のみを用いてもよく、２種類以上を組み合わせて用いてもよい。 <Non-aqueous electrolyte>
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. As the non-aqueous electrolyte, for example, a non-aqueous electrolyte obtained by dissolving a lithium salt in an organic solvent can be used. Examples of the lithium salt 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.
　非水電解液を構成する有機溶媒としては、例えば、カーボネート類、エーテル類、エステル類、ニトリル類、アミド類、カーバメート類および含硫黄化合物、ならびにこれらの有機溶媒にフッ素基が導入されてなる含フッ素有機溶媒等が挙げられる。前記有機溶媒は、１種類のみを用いてもよく、２種類以上を組み合わせて用いてもよい。 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.
　＜非水電解液二次電池の製造方法＞
　本発明の一実施形態に係る非水二次電池の製造方法としては、従来公知の製造方法を採用することができる。例えば、正極板、ポリオレフィン多孔質フィルムおよび負極板をこの順で配置することにより非水電解液二次電池用部材を形成する。ここで、多孔質層は、ポリオレフィン多孔質フィルムと正極板および負極板の少なくとも一方との間に存在し得る。次いで、非水電解液二次電池の筐体となる容器に当該非水電解液二次電池用部材を入れる。当該容器内を前記非水電解液で満たした後、減圧しつつ密閉する。これにより、本発明の一実施形態に係る非水電解液二次電池を製造することができる。 <Method for manufacturing non-aqueous electrolyte secondary battery>
As a method for manufacturing the non-aqueous secondary battery according to the embodiment of the present invention, a conventionally known manufacturing method can be adopted. For example, a positive electrode plate, a polyolefin porous film, and a negative electrode plate are arranged in this order to form a member for a non-aqueous electrolyte secondary battery. Here, the porous layer may be present between the polyolefin porous film and at least one of the positive electrode plate and the negative electrode plate. Then, the member for a non-aqueous electrolyte secondary battery is put in a container which is a casing of the non-aqueous electrolyte secondary battery. After filling the inside of the container with the non-aqueous electrolyte, the container is sealed while reducing the pressure. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
　本発明は上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.
　以下、実施例および比較例により、本発明をさらに詳細に説明するが、本発明はこれら実施例に限定されるものではない。
［測定方法］
　実施例および比較例にて製造された多孔質層、ポリオレフィン多孔質フィルムの物性等、並びに、非水電解液二次電池の１００サイクルの充放電後の充電回復容量を、以下の方法を用いて測定した。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[Measuring method]
Using the following methods, the porous layer produced in Examples and Comparative Examples, the physical properties of the polyolefin porous film, and the charge recovery capacity after 100 cycles of charge / discharge of the non-aqueous electrolyte secondary battery were measured. It was measured.
　（１）膜厚（単位：μｍ）
　ポリオレフィン多孔質フィルムおよび多孔質層の膜厚は、株式会社ミツトヨ製の高精度デジタル測長機（ＶＬ－５０）を用いて測定した。多孔質層の膜厚は、各々の積層体において多孔質層が形成されている部分の膜厚から、多孔質層が形成されていない部分の膜厚を引いた値とした。 (1) Film thickness (unit: μm)
The thickness of the polyolefin porous film and the porous layer was measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. The film thickness of the porous layer was a value obtained by subtracting the film thickness of the part where the porous layer was not formed from the film thickness of the part where the porous layer was formed in each laminate.
　（２）多孔質層表面の無機フィラーの投影像のアスペクト比の測定
　実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体の多孔質層側から、日本電子製　電界放出形走査電子顕微鏡ＪＳＭ－７６００Ｆを用い、加速電圧５ｋＶでＳＥＭ表面観察（反射電子像）を行い、電子顕微鏡写真（ＳＥＭ画像）を得た。 (2) Measurement of Aspect Ratio of Projection Image of Inorganic Filler on Surface of Porous Layer From the porous layer side of the laminate comprising the polyolefin porous film and the porous layer produced in Examples and Comparative Examples, JEOL Ltd. Using a field emission scanning electron microscope JSM-7600F, SEM surface observation (backscattered electron image) was performed at an accelerating voltage of 5 kV to obtain an electron microscope photograph (SEM image).
　得られたＳＥＭ画像上にＯＨＰフィルムを載せ、無機フィラーの粒子の輪郭に沿って敷き写した投影像を作成し、該投影像をデジタルスチルカメラにより撮影した。得られた写真のデータをコンピュータに取り込み、アメリカ国立衛生研究所（ＮＩＨ：Ｎａｔｉｏｎａｌ Ｉｎｓｔｉｔｕｅｓ ｏｆ Ｈｅａｌｔｈ）が発行する画像解析のフリーソフトＩＭＡＧＥＪを用いて、粒子１００個の各々のアスペクト比を算出し、その平均を多孔質層における多孔質層表面の無機フィラーの投影像のアスペクト比（以下、「表面フィラーアスペクト比」とも称する）とした。ここで無機フィラー１粒子ずつを楕円形に近似させ、長軸径と短軸径を算出し、長軸径を短軸径で除した値を無機フィラー１個当たりのアスペクト比とした。 An OHP film was placed on the obtained SEM image to create a projected image laid out along the contours of the particles of the inorganic filler, and the projected image was taken by a digital still camera. The obtained photograph data is loaded into a computer, and the aspect ratio of each of 100 particles is calculated using the free image analysis software IMAGEJ issued by the National Institutes of Health (NIH). The average was defined as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer in the porous layer (hereinafter, also referred to as “surface filler aspect ratio”). Here, each particle of the inorganic filler was approximated to an ellipse, the major axis diameter and the minor axis diameter were calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter was defined as the aspect ratio per inorganic filler.
　（３）ピーク強度比の最大値の測定
　実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体を２ｃｍ角に切り取り、測定用サンプルを得た。得られた測定用サンプルを、当該サンプルにおける多孔質層を測定面として、Ａｌ製ホルダーに取り付け広角Ｘ線回折法（２θ－θスキャン法）でＸ線プロファイルを測定した。装置として理学電機社製ＲＵ－２００Ｒ（回転対陰極型）を使用し、Ｘ線源にＣｕＫα線を用い、出力は５０ＫＶ-２００ｍＡ、スキャン速度２°／ｍｉｎにて測定した。 (3) Measurement of maximum value of peak intensity ratio The laminate composed of the polyolefin porous film and the porous layer produced in Examples and Comparative Examples was cut into a 2 cm square to obtain a measurement sample. The obtained measurement sample was attached to an Al holder with the porous layer of the sample as the measurement surface, and the X-ray profile was measured by the wide-angle X-ray diffraction method (2θ-θ scan method). RU-200R (rotating anticathode type) manufactured by Rigaku Denki Co., Ltd. was used as an apparatus, CuKα rays were used as an X-ray source, and the output was measured at 50 KV-200 mA and a scan speed of 2 ° / min.
　得られたＸ線プロファイルに基づき、多孔質層の広角Ｘ線回折測定における、直交する任意の回折面（ｈｋｌ）および（ａｂｃ）のピーク強度　Ｉ（ｈｋｌ）およびＩ（ａｂｃ）が下式（１）を満たす場合の、Ｉ（ｈｋｌ）／Ｉ（ａｂｃ）で算出されるピーク強度比を算出し、そのピーク強度比の最大値を算出した。
Ｉ（ｈｋｌ）＞　Ｉ（ａｂｃ）・・・（１）。 Based on the obtained X-ray profile, the peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in the wide-angle X-ray diffraction measurement of the porous layer are represented by the following formula (1 ). The peak intensity ratio calculated by I (hkl) / I (abc) in the case of satisfying (1) is calculated, and the maximum value of the peak intensity ratio is calculated.
I (hkl) > I (abc) ... (1).
　（４）耐折試験
　実施例および比較例において得られた正極板または負極板から、長さ１０５ｍｍ×幅１５ｍｍの試験片を切り出した。この試験片を用いてＭＩＴ試験機法に準じ、耐折試験を行った。 (4) Folding resistance test A test piece having a length of 105 mm and a width of 15 mm was cut out from each of the positive electrode plate and the negative electrode plate obtained in Examples and Comparative Examples. Using this test piece, a folding endurance test was performed according to the MIT tester method.
　耐折試験はＭＩＴ型耐折試験機（安田精機製）を用い、ＪＩＳ　Ｐ　８１１５（１９９４）に規定されたＭＩＴ試験機法に準じて、荷重：１Ｎ、折り曲げ部Ｒ：０．３８ｍｍ、折り曲げ速度１７５往復／分とし、試験片の一端を固定し左右へ４５度の角度に折り曲げることによって行った。 For the folding endurance test, a MIT type folding endurance tester (manufactured by Yasuda Seiki) was used, and in accordance with the MIT tester method specified in JIS P 8115 (1994), 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.
　これにより、正極板または負極板から電極活物質層が剥がれるまでの折り曲げ回数を測定した。ここでの折り曲げ回数は、前記ＭＩＴ型耐折試験機のカウンターに表示される往復折り曲げ回数のことである。 With this, 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.
　（５）１００サイクルの充放電後の充電回復容量
　（５－１）初期充放電
　実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体を備え、かつ、充放電サイクルを経ていない新たな非水電解液二次電池に対して、電圧範囲：２．７～４．１Ｖ、充電電流値：０．２ＣのＣＣ－ＣＶ充電（終止電流条件０．０２Ｃ）、放電電流値：０．２ＣのＣＣ放電を１サイクルとして、４サイクルの初期充放電を２５℃にて行った。ここで、１Ｃとは、１時間率の放電容量による定格容量を１時間で放電する電流値である。また、ＣＣ－ＣＶ充電とは、設定した一定の電流で充電し、所定の電圧に到達後、電流を絞りながら、その電圧を維持する充電方法である。さらに、ＣＣ放電とは、設定した一定の電流で所定の電圧まで放電する方法である。これらの用語の意味は、本明細書において同様である。 (5) Charge recovery capacity after 100 cycles of charging / discharging (5-1) Initial charging / discharging The laminated body comprising the polyolefin porous film and the porous layer produced in Examples and Comparative Examples is provided and charged. For a new non-aqueous electrolyte secondary battery that has not undergone a discharge cycle, CC-CV charging with a voltage range of 2.7 to 4.1 V and a charging current value of 0.2 C (end current condition 0.02 C), Discharge current value: CC discharge of 0.2 C was defined as one cycle, and initial charge and discharge for four cycles were performed at 25 ° C. Here, 1C is a current value for discharging the rated capacity by the discharge capacity of 1 hour rate in 1 hour. 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. Further, 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.
　（５－２）サイクル試験
　初期充放電後の非水電解液二次電池を、電圧範囲：２．７～４．２Ｖ、充電電流値：１ＣのＣＣ－ＣＶ充電（終止電流条件０．０２Ｃ）、放電電流値：１０ＣのＣＣ放電を１サイクルとして、１００サイクルの充放電を５５℃にて実施した。 (5-2) Cycle test The non-aqueous electrolyte secondary battery after initial charge / discharge was CC-CV charged with a voltage range of 2.7 to 4.2 V and a charging current value of 1 C (end current condition 0.02 C). A discharge current value: CC discharge of 10 C was defined as one cycle, and 100 cycles of charge and discharge were carried out at 55 ° C.
　（５－３）１００サイクルの充放電後の充電回復容量試験
　１００サイクルの充放電を行った非水電解液二次電池に対して、電圧範囲：２．７Ｖ～４．２Ｖ、充電電流値：１ＣのＣＣ－ＣＶ充電（終止電流条件０．０２Ｃ）、放電電流値：０．２ＣのＣＣ放電を１サイクルとして３サイクルの充放電を５５℃にて実施した。その３サイクル目の充電容量を１００サイクルの充放電後の充電回復容量とした。 (5-3) Charge recovery capacity test after 100 cycles of charging / discharging With respect to the non-aqueous electrolyte secondary battery charged / discharged for 100 cycles, voltage range: 2.7 V to 4.2 V, charging current value: CC-CV charging of 1 C (final current condition 0.02 C) and CC discharging of discharge current value: 0.2 C were set as one cycle, and three cycles of charging and discharging were carried out at 55 ° C. The charge capacity at the third cycle was defined as the charge recovery capacity after 100 cycles of charge / discharge.
　前記充電回復容量試験は、充放電サイクル後に低いレート（０．２Ｃ）で放電を実施して電池内部の容量を空にした後に、より正確に充電容量を確認する試験方法であり、電池全体の充電性能の劣化度、特に電極の充電性能の劣化度を確認することができる。 The charge recovery capacity test is a test method for confirming the charge capacity more accurately after performing discharge at a low rate (0.2 C) after the charge / discharge cycle to empty the internal capacity of the battery. It is possible to confirm the degree of deterioration of the charging performance, particularly the degree of deterioration of the charging performance of the electrodes.
　［実施例１］
　［多孔質基材（Ａ層）の製造]
　ポリオレフィンであるポリエチレンを用いて、ポリオレフィン多孔質フィルムである多孔質基材を作製した。 [Example 1]
[Production of Porous Substrate (A Layer)]
A porous substrate, which is a polyolefin porous film, was produced using polyethylene, which is a polyolefin.
　即ち、超高分子量ポリエチレン粉末（３４０Ｍ、三井化学株式会社製）７０重量部と、重量平均分子量１０００のポリエチレンワックス（ＦＮＰ－０１１５、日本精鑞株式会社製）３０重量部とを混合して混合ポリエチレンを得た。 That is, 70 parts by weight of ultra-high molecular weight polyethylene powder (340M, manufactured by Mitsui Chemicals, Inc.) and 30 parts by weight of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiro Co., Ltd.) are mixed and mixed polyethylene. Got
　得られた混合ポリエチレン１００重量部に対して、酸化防止剤（Ｉｒｇ１０１０、チバ・スペシャリティ・ケミカルズ株式会社製）０．４重量部、酸化防止剤（Ｐ１６８、チバ・スペシャリティ・ケミカルズ株式会社製）０．１重量部、およびステアリン酸ナトリウム１．３重量部を加え、さらに、全体積に占める割合が３８体積％となるように、平均粒子径０．１μｍの炭酸カルシウム（丸尾カルシウム株式会社製）を加えた。この組成物を粉末のまま、ヘンシェルミキサーで混合した後、二軸混練機で溶融混練することにより、ポリエチレン樹脂組成物を得た。 For 100 parts by weight of the obtained mixed polyethylene, 0.4 parts by weight of an antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals Co., Ltd.), and an antioxidant (P168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1 part by weight and 1.3 parts by weight of sodium stearate were added, and further, calcium carbonate having an average particle size of 0.1 μm (manufactured by Maruo Calcium Co., Ltd.) was added so that the ratio of the total volume was 38% by volume. It was This composition as a powder was mixed with a Henschel mixer and then melt-kneaded with a biaxial kneader to obtain a polyethylene resin composition.
　次いで、このポリエチレン樹脂組成物を、表面温度が１５０℃に設定された一対のロールにて圧延することにより、シートを作製した。このシートを、４ｍｏｌ／Ｌの塩酸に０．５重量％の非イオン系界面活性剤を配合して調製した塩酸水溶液に浸漬させることで炭酸カルシウムを溶解して除去した。続いて、当該シートを１０５℃で６倍に延伸することにより、ポリエチレン製の多孔質基材（Ａ層）を作製した。当該多孔質基材の空隙率は５３％、目付は７ｇ／ｍ２、膜厚は１６μｍであった。 Then, this polyethylene resin composition was rolled with a pair of rolls whose surface temperature was set to 150 ° C. to prepare a sheet. 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 | seat was drawn 6 times at 105 degreeC, and the porous base material (A layer) made from polyethylene was produced. The porosity of the porous substrate was 53%, the basis weight was 7 g / m 2 , and the film thickness was 16 μm.
　［多孔質層（Ｂ層）の製造]
　（塗工液の製造）
　無機フィラーとして、酸素原子質量百分率が２０％である六角板状酸化亜鉛（堺化学工業株式会社製、商品名：ＸＺ－１００Ｆ）を用いた。当該無機フィラーを、無機フィラー１とする。本明細書において、無機フィラーの体積基準の粒度分布の算出は、島津製作所製　レーザー回折式粒度分布計ＳＡＬＤ２２００を使用してＤ１０、Ｄ５０、Ｄ９０を測定することにより行った。ここで体積基準による積算分布が５０％になる値の粒子径、１０％になる値の粒子径、９０％になる値の粒子径を、それぞれＤ５０、Ｄ１０、Ｄ９０と呼ぶ。無機フィラー１のＤ１０、Ｄ５０、Ｄ９０は、それぞれ０．２μｍ、０．４μｍ、２．１μｍであった。 [Production of Porous Layer (B Layer)]
(Production of coating liquid)
As the inorganic filler, hexagonal plate-shaped zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) having an oxygen atom mass percentage of 20% was used. Let the inorganic filler be the inorganic filler 1. In this specification, the volume-based particle size distribution of the inorganic filler was calculated by measuring D10, D50, and D90 using a laser diffraction particle size distribution analyzer SALD2200 manufactured by Shimadzu Corporation. Here, 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. D10, D50, and D90 of the inorganic filler 1 were 0.2 μm, 0.4 μm, and 2.1 μm, respectively.
　バインダー樹脂としては、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体（アルケマ株式会社製；商品名「ＫＹＮＡＲ２８０１」）を用いた。 As the binder resin, a vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Ltd .; trade name “KYNAR2801”) was used.
　本明細書において、無機フィラーの比表面積は、定容法を用いて、窒素による吸着脱離等温線を測定し、ＢＥＴ法によって算出した。具体的には、実施例および比較例において、単位質量当たりのＢＥＴ比表面積を、ＢＥＬＳＯＲＰ－ｍｉｎｉ（マイクロトラック・ベル株式会社製）を用いて測定した。前処理温度８０℃で８時間真空乾燥を行ったフィラーを、定容法を用いて、窒素による吸着脱離等温線を測定し、ＢＥＴ法にて算出した。定容法における各種条件は、以下のとおりである：吸着温度；７７Ｋ、吸着質；窒素、飽和蒸気圧；実測値、吸着質断面積；０．１６２ｎｍ２、平衡待ち時間（吸着平衡状態（吸脱着の際の圧力変化が所定の値以下になる状態）に達してからの待ち時間）；５００ｓｅｃ。また、細孔容積は、ＭＰ法、ＢＪＨ法により算出し、前処理装置は、ＢＥＬＰＲＥＰ－ｖａｃＩＩ（マイクロトラック・ベル株式会社製）を用いた。無機フィラー１の単位質量当たりのＢＥＴ比表面積は、７．３ｍ２／ｇであった。 In the present specification, the specific surface area of the inorganic filler was calculated by the BET method by measuring the adsorption-desorption isotherm with nitrogen using a constant volume method. Specifically, in Examples and Comparative Examples, the BET specific surface area per unit mass 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.). The BET specific surface area per unit mass of the inorganic filler 1 was 7.3 m 2 / g.
　無機フィラー１、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体および溶媒（関東化学株式会社製　Ｎ-メチル－２－ピロリジノン）を、下記割合となるように混合した。すなわち、無機フィラー１（９０重量部）に対してフッ化ビニリデン－ヘキサフルオロプロピレン共重合体を１０重量部混合すると共に、無機フィラー１およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が混合液において３７重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を薄膜旋回型高速ミキサー（プライミクス（株）製フィルミク（登録商標））で攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液１とする。 Inorganic filler 1, vinylidene fluoride-hexafluoropropylene copolymer and solvent (N-methyl-2-pyrrolidinone manufactured by Kanto Chemical Co., Inc.) were mixed in the following proportions. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with 1 (90 parts by weight) of the inorganic filler, and the solid content of the inorganic filler 1 and the vinylidene fluoride-hexafluoropropylene copolymer was mixed. A solvent was mixed so that the concentration of the mixed solution would be 37% by weight to prepare a mixed solution. 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. The coating liquid is referred to as coating liquid 1.
　（多項質層、積層体の製造）
　塗工液１を、ドクターブレード法により、前記Ａ層の片面に、塗工せん断速度３．９（１／ｓ）にて塗工し、前記Ａ層の片面に塗膜を形成した。その後、前記塗膜を、６５℃にて２０分間かけて乾燥することによって、前記Ａ層の片面にＢ層を形成した。これにより、Ａ層の片面にＢ層が積層された積層体１（積層セパレータ）を得た。Ｂ層の目付は７ｇ／ｍ２であり、厚みは４μｍであった。 (Manufacture of multi-layered layer and laminate)
The 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. Then, the coating film was dried at 65 ° C. for 20 minutes to form a B layer on one surface of the A layer. As a result, a laminate 1 (laminated separator) in 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 μm.
　〔非水電解液二次電池の作製〕
　（正極板）
　正極合剤として、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｏ２／導電剤／ＰＶＤＦ（重量比：９２／５／３）を、正極集電体であるアルミニウム箔の片面に積層することにより、正極板を得た。当該正極板に対して、室温で３０秒間、拘束圧（０．７ＭＰａ）をかけた。 [Preparation of non-aqueous electrolyte secondary battery]
(Positive plate)
Laminating LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio: 92/5/3) as a positive electrode mixture on one side of an aluminum foil which is a positive electrode current collector. Thus, a positive electrode plate was obtained. A binding pressure (0.7 MPa) was applied to the positive electrode plate at room temperature for 30 seconds.
　前記正極板を、正極活物質層が積層された部分の大きさが４５ｍｍ×３０ｍｍであり、かつ、その外周に、正極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、正極板１を得た。正極板１の正極活物質層の厚さは３８μｍであった。 By cutting the positive electrode plate 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 remains on the outer periphery with a width of 13 mm. A positive electrode plate 1 was obtained. The thickness of the positive electrode active material layer of the positive electrode plate 1 was 38 μm.
　（負極板）
　負極合剤として、体積基準の平均粒径（Ｄ５０）が１５μｍである天然黒鉛／スチレン－１，３－ブタジエン共重合体／カルボキシメチルセルロースナトリウム（重量比９８／１／１）を、負極集電体である銅箔の片面に積層することにより、負極板を得た。当該負極板に対して、室温で３０秒間、拘束圧（０．７ＭＰａ）をかけた。 (Negative electrode plate)
As the negative electrode mixture, natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethylcellulose (weight ratio 98/1/1) having a volume-based average particle size (D50) of 15 μm was used as a negative electrode current collector. The negative electrode plate was obtained by laminating the copper foil on one surface. A binding pressure (0.7 MPa) was applied to the negative electrode plate at room temperature for 30 seconds.
　前記負極板を、負極活物質層が積層された部分の大きさが５０ｍｍ×３５ｍｍであり、かつ、その外周に、負極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、負極板１を得た。負極板１の負極活物質層の厚さは３８μｍであった。 By cutting the negative electrode plate so that the size of the portion where the negative electrode active material layer is laminated is 50 mm × 35 mm, and the portion where the negative electrode active material layer is not laminated remains on the outer periphery with a width of 13 mm. A negative electrode plate 1 was obtained. The thickness of the negative electrode active material layer of the negative electrode plate 1 was 38 μm.
　（非水電解液二次電池の組み立て）
　正極板１、負極板１および積層体１を使用して、以下に示す方法にて非水電解液二次電池を製造した。 (Assembly of non-aqueous electrolyte secondary battery)
Using the positive electrode plate 1, the negative electrode plate 1 and the laminate 1, a non-aqueous electrolyte secondary battery was manufactured by the method described below.
　まず、ラミネートパウチ内で、正極板１、積層体１および負極板１をこの順で積層（配置）することにより、非水電解液二次電池用部材１を得た。このとき、正極板１の正極活物質層における主面の全部が、負極板１の負極活物質層における主面の範囲に含まれるように、正極板１および負極板１を配置した。すなわち、正極板１の正極活物質層における主面の全部が、負極板１の負極活物質層における主面に重なるように、正極板１および負極板１を配置した。また、積層体１の多孔質層側の面を、正極板１の正極活物質層に対向させた。 First, a positive electrode plate 1, a laminate 1 and a negative electrode plate 1 were laminated (arranged) in this order in a laminate pouch to obtain a non-aqueous electrolyte secondary battery member 1. At this time, 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.
　続いて、非水電解液二次電池用部材１を、予め作製していた、アルミニウム層とヒートシール層とが積層されてなる袋に入れ、さらにこの袋に非水電解液を０．２３ｍＬ入れた。前記非水電解液は、エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを体積比３：５：２で混合してなる混合溶媒に、ＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解することにより、調製した。そして、袋内を減圧しつつ、当該袋をヒートシールすることにより、非水電解液二次電池１を作製した。その後、非水電解液二次電池１の電池特性の測定を行った。その結果を表１に示す。 Then, 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 was prepared by dissolving LiPF 6 in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate at a volume ratio of 3: 5: 2 so as to be 1 mol / L. .. Then, the inside of the bag was depressurized and the bag was heat-sealed to manufacture the non-aqueous electrolyte secondary battery 1. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 1 were measured. The results are shown in Table 1.
　［実施例２］
　〔多孔質層、積層体の作製〕
　無機フィラーとして、球状アルミナ（住友化学株式会社製、商品名ＡＡ０３）と、マイカ（株式会社和光純薬製、商品名：非膨潤性合成雲母）との混合物を用いた。前記混合物は、球状アルミナ５０重量部とマイカ５０重量部とを乳鉢で混合することによって調製した。前記混合物を無機フィラー２とする。無機フィラー２の酸素原子質量百分率は、４５％であった。また、無機フィラー２のＤ１０、Ｄ５０、Ｄ９０は、それぞれ０．５μｍ、４．２μｍ、１１．５μｍであった。さらに、無機フィラー２の単位質量当たりのＢＥＴ比表面積は、４．５ｍ２／ｇであった。 [Example 2]
[Preparation of porous layer and laminate]
As the inorganic filler, 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 mixture was prepared by mixing 50 parts by weight of spherical alumina and 50 parts by weight of mica in a mortar. Let the said mixture be the inorganic filler 2. The oxygen atom mass percentage of the inorganic filler 2 was 45%. Further, D10, D50, and D90 of the inorganic filler 2 were 0.5 μm, 4.2 μm, and 11.5 μm, respectively. Furthermore, the BET specific surface area per unit mass of the inorganic filler 2 was 4.5 m 2 / g.
　塗工液は、以下の通り調製した。すなわち、無機フィラー２（９０重量部）に対して、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体１０重量部を混合すると共に、無機フィラー２およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が、混合液において３０重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を、前記薄膜旋回型高速ミキサーで攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液２とする。 The coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with inorganic filler 2 (90 parts by weight), and the solid content of inorganic filler 2 and vinylidene fluoride-hexafluoropropylene copolymer was mixed. The solvent was mixed so that the concentration of the above was 30% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 2.
　多孔質層（Ｂ層）の作製に使用した無機フィラーを前記無機フィラー２に変更し、塗工液を前記塗工液２に変更し、塗工せん断速度を７．９（１／ｓ）に変更したこと以外は、実施例１と同様にして、積層体２を得た。 The inorganic filler used in the production of the porous layer (B layer) was changed to the inorganic filler 2, the coating liquid was changed to the coating liquid 2, and the coating shear rate was 7.9 (1 / s). A laminate 2 was obtained in the same manner as in Example 1 except that the changes were made.
　〔非水電解液二次電池の作製〕
　積層体１の代わりに、積層体２を使用したこと以外は、実施例１と同様にして、非水電解液二次電池２を得た。その後、非水電解液二次電池２の電池特性の測定を行った。その結果を表１に示す。 [Preparation of non-aqueous electrolyte secondary battery]
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 2 were measured. The results are shown in Table 1.
　［実施例３］
　〔多孔質層、積層体の作製〕
　無機フィラーとして、酸素原子質量百分率が４２％であるワラストナイト（林化成株式会社製、商品名：ワラストナイト　ＶＭ－８Ｎ）を用いた。前記ワラストナイトを無機フィラー３とする。無機フィラー３のＤ１０、Ｄ５０、Ｄ９０は、それぞれ２．４μｍ、１０．６μｍ、２５．３μｍであった。また、無機フィラー３の単位質量当たりのＢＥＴ比表面積は、１．３ｍ２／ｇであった。 [Example 3]
[Preparation of porous layer and laminate]
As the inorganic filler, wollastonite (Wallastonite VM-8N, manufactured by Hayashi Kasei Co., Ltd.) having an oxygen atomic mass percentage of 42% was used. The wollastonite is the inorganic filler 3. D10, D50, and D90 of the inorganic filler 3 were 2.4 μm, 10.6 μm, and 25.3 μm, respectively. The BET specific surface area per unit mass of the inorganic filler 3 was 1.3 m 2 / g.
　塗工液は、以下の通り調製した。すなわち、無機フィラー３（９０重量部）に対して、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体１０重量部を混合すると共に、無機フィラー３およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が、混合液において４０重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を、前記薄膜旋回型高速ミキサーで攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液３とする。 The coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with inorganic filler 3 (90 parts by weight), and the solid content of inorganic filler 3 and vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the above was 40% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed with the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 3.
　多孔質層（Ｂ層）の作製に使用した無機フィラーを前記無機フィラー３に変更し、塗工液を前記塗工液３に変更し、塗工せん断速度を７．９（１／ｓ）に変更したこと以外は、実施例１と同様にして、積層体３を得た。 The inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 3, the coating liquid was changed to the coating liquid 3, and the coating shear rate was 7.9 (1 / s). A laminate 3 was obtained in the same manner as in Example 1 except that the changes were made.
　〔非水電解液二次電池の作製〕
　積層体１の代わりに、積層体３を使用したこと以外は、実施例１と同様にして、非水電解液二次電池３を得た。その後、非水電解液二次電池３の電池特性の測定を行った。その結果を表１に示す。 [Preparation of non-aqueous electrolyte secondary battery]
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 3 were measured. The results are shown in Table 1.
　［実施例４］
　〔多孔質層、積層体の作製〕
　無機フィラーとして、αアルミナ（住友化学株式会社製、商品名：ＡＫＰ３０００）と、六角板状酸化亜鉛（堺化学工業株式会社製、商品名：ＸＺ－１０００Ｆ）との混合物を用いた。前記混合物は、αアルミナ９９重量部と六角板状酸化亜鉛１重量部とを乳鉢で混合することによって調製した。前記混合物を無機フィラー４とする。無機フィラー４の酸素原子質量百分率は、４７％であった。また、無機フィラー４のＤ１０、Ｄ５０、Ｄ９０は、それぞれ０．４μｍ、０．８μｍ、２．２μｍであった。さらに、無機フィラー４の単位質量当たりのＢＥＴ比表面積は、４．５ｍ２／ｇであった。 [Example 4]
[Preparation of porous layer and laminate]
As the inorganic filler, a mixture of α-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 mixture was prepared by mixing 99 parts by weight of α-alumina and 1 part by weight of hexagonal plate-shaped zinc oxide in a mortar. Let the said mixture be the inorganic filler 4. The oxygen atom mass percentage of the inorganic filler 4 was 47%. Further, D10, D50, and D90 of the inorganic filler 4 were 0.4 μm, 0.8 μm, and 2.2 μm, respectively. Furthermore, the BET specific surface area per unit mass of the inorganic filler 4 was 4.5 m 2 / g.
　塗工液は、以下の通り作製した。すなわち、無機フィラー４（９０重量部）に対して、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体１０重量部を混合すると共に、無機フィラー４およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が、混合液において４０重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を、前記薄膜旋回型高速ミキサーで攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液４とする。 The coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was mixed with inorganic filler 4 (90 parts by weight), and the solid content of inorganic filler 4 and vinylidene fluoride-hexafluoropropylene copolymer was mixed. The solvent was mixed so that the concentration of the above would be 40% by weight in the mixed solution to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 4.
　多孔質層（Ｂ層）の作製に使用した無機フィラーを前記無機フィラー４に変更し、塗工液を前記塗工液４に変更し、塗工せん断速度を３９．４（１／ｓ）に変更したこと以外は、実施例１と同様にして、積層体４を得た。 The inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 4, the coating liquid was changed to the 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 it was changed.
　〔非水電解液二次電池の作製〕
　（正極板）
　正極合剤として、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｏ２／導電剤／ＰＶＤＦ（重量比：９２／５／３）を、正極集電体であるアルミニウム箔の片面に積層することにより、正極板を得た。当該正極板をジエチルカーボネートによって湿潤させた状態で、当該正極板に対して、室温で３０秒間拘束圧（０．７ＭＰａ）をかけた。 [Preparation of non-aqueous electrolyte secondary battery]
(Positive plate)
Laminating LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio: 92/5/3) as a positive electrode mixture on one side of an aluminum foil which is a positive electrode current collector. Thus, a positive electrode plate was obtained. With the positive electrode plate wet with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the positive electrode plate at room temperature for 30 seconds.
　前記正極板を、正極活物質層が積層された部分の大きさが４５ｍｍ×３０ｍｍであり、かつ、その外周に、正極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、正極板２を得た。正極板２の正極活物質層の厚さは３７μｍであった。 By cutting the positive electrode plate so that the size of the portion where the positive electrode active material layer is laminated is 45 mm × 30 mm, and the portion where the positive electrode active material layer is not laminated is left on its outer periphery with a width of 13 mm. A positive electrode plate 2 was obtained. The thickness of the positive electrode active material layer of the positive electrode plate 2 was 37 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、正極板として前記正極板２を使用したこと以外は、実施例１と同様にして、非水電解液二次電池４を得た。その後、非水電解液二次電池４の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 4 were measured. The results are shown in Table 1.
　［実施例５］
　〔非水電解液二次電池の作製〕
　（正極板）
　正極合剤として、ＬｉＣｏＯ２／導電剤／ＰＶＤＦ（重量比：１００／５／３）を、正極集電体であるアルミニウム箔の片面に積層することにより、正極板を得た。当該正極板をジエチルカーボネートによって湿潤させた状態で、当該正極板に対して、室温で３０秒間拘束圧（０．７ＭＰａ）をかけた。 [Example 5]
[Preparation of non-aqueous electrolyte secondary battery]
(Positive plate)
A positive electrode plate was obtained by laminating LiCoO 2 / conductive agent / PVDF (weight ratio: 100/5/3) as a positive electrode mixture on one side of an aluminum foil that is a positive electrode current collector. With the positive electrode plate wet with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the positive electrode plate at room temperature for 30 seconds.
　前記正極板を、正極活物質層が積層された部分の大きさが４５ｍｍ×３０ｍｍであり、かつ、その外周に、正極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、正極板３を得た。正極活物質層の厚さは３８μｍであった。 By cutting the positive electrode plate so that the size of the portion where the positive electrode active material layer is laminated is 45 mm × 30 mm, and the portion where the positive electrode active material layer is not laminated is left on its outer periphery with a width of 13 mm. A positive electrode plate 3 was obtained. The thickness of the positive electrode active material layer was 38 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、正極板として前記正極板３を使用したこと以外は、実施例１と同様にして、非水電解液二次電池５を得た。その後、非水電解液二次電池５の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 5 were measured. The results are shown in Table 1.
　［実施例６］
　〔非水電解液二次電池の作製〕
　（負極板）
　負極合剤として、天然黒鉛／スチレン－１，３－ブタジエン共重合体／カルボキシメチルセルロースナトリウム（重量比９８／１／１）を、負極集電体である銅箔の片面に積層することにより、負極板を得た。当該負極板をジエチルカーボネートによって湿潤させた状態で、当該負極板に対して、室温で３０秒間拘束圧（０．７ＭＰａ）をかけた。 [Example 6]
[Preparation of non-aqueous electrolyte secondary battery]
(Negative electrode plate)
By laminating natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) as a negative electrode mixture on one side of a copper foil which is a negative electrode current collector, I got a board. With the negative electrode plate moistened with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the negative electrode plate at room temperature for 30 seconds.
　前記負極板を、負極活物質層が積層された部分の大きさが５０ｍｍ×３５ｍｍであり、かつ、その外周に、負極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、負極板２を得た。負極板２の負極活物質層の厚さは３７μｍであった。 By cutting the negative electrode plate so that the size of the portion where the negative electrode active material layer is laminated is 50 mm × 35 mm, and the portion where the negative electrode active material layer is not laminated remains on the outer periphery with a width of 13 mm. A negative electrode plate 2 was obtained. The thickness of the negative electrode active material layer of the negative electrode plate 2 was 37 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、負極板として前記負極板２を使用したこと以外は、実施例１と同様にして、非水電解液二次電池６を得た。その後、非水電解液二次電池６の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 6 were measured. The results are shown in Table 1.
　［実施例７］
　〔非水電解液二次電池の作製〕
　（負極板）
　負極合剤として、人造球晶黒鉛／導電剤／ＰＶＤＦ（重量比８５／１５／７．５）を、負極集電体である銅箔の片面に積層することにより、負極板を得た。当該負極板をジエチルカーボネートによって湿潤させた状態で、当該負極板に対して、室温で３０秒間拘束圧（０．７ＭＰａ）をかけた。 [Example 7]
[Preparation of non-aqueous electrolyte secondary battery]
(Negative electrode plate)
As a negative electrode mixture, artificial spherulite graphite / conductive agent / PVDF (weight ratio 85/15 / 7.5) was laminated on one surface of a copper foil as a negative electrode current collector to obtain a negative electrode plate. With the negative electrode plate moistened with diethyl carbonate, a binding pressure (0.7 MPa) was applied to the negative electrode plate at room temperature for 30 seconds.
　前記負極板を、負極活物質層が積層された部分の大きさが５０ｍｍ×３５ｍｍであり、かつ、その外周に、負極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、負極板３を得た。負極板３の負極活物質層の厚さは３６μｍであった。 By cutting the negative electrode plate so that the size of the portion where the negative electrode active material layer is laminated is 50 mm × 35 mm, and the portion where the negative electrode active material layer is not laminated remains on the outer periphery with a width of 13 mm. A negative electrode plate 3 was obtained. The thickness of the negative electrode active material layer of the negative electrode plate 3 was 36 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、負極板として前記負極板３を使用したこと以外は、実施例１と同様にして、非水電解液二次電池７を得た。その後、非水電解液二次電池７の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 7 were measured. The results are shown in Table 1.
　［比較例１］
　〔多孔質層、積層体の作製〕
　無機フィラーとして、酸素原子質量百分率が４８％であるアタパルジャイト（林化成株式会社製、商品名：ＡＴＴＡＧＥＬ＃５０）を用いた。前記アタパルジャイトを無機フィラー５とする。無機フィラー５のＤ１０、Ｄ５０、Ｄ９０は、それぞれ０．４μｍ、２．０μｍ、３．３μｍであった。また、無機フィラー５の単位質量当たりのＢＥＴ比表面積は、２３５．０ｍ２／ｇであった。 [Comparative Example 1]
[Preparation of porous layer and laminate]
As the inorganic filler, attapulgite (manufactured by Hayashi Kasei Co., Ltd., trade name: ATTAGEL # 50) having an oxygen atomic mass percentage of 48% was used. The attapulgite is the inorganic filler 5. D10, D50, and D90 of the inorganic filler 5 were 0.4 μm, 2.0 μm, and 3.3 μm, respectively. The BET specific surface area per unit mass of the inorganic filler 5 was 235.0 m 2 / g.
　塗工液は、以下の通り作製した。すなわち、無機フィラー５（９０重量部）に対してフッ化ビニリデン－ヘキサフルオロプロピレン共重合体１０重量部を混合すると共に、無機フィラー５およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が、混合液において１７重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を、前記薄膜旋回型高速ミキサーで攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液５とする。 The coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with 5 (90 parts by weight) of the inorganic filler, and the solid content of the inorganic filler 5 and the vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the mixed solution would be 17% by weight to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 5.
　多孔質層（Ｂ層）の作製に使用した無機フィラーを前記無機フィラー５に変更し、塗工液を前記塗工液５に変更し、塗工せん断速度を１．３（１／ｓ）に変更したこと以外は、実施例１と同様にして、積層体５を得た。 The inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 5, the coating liquid was changed to the coating liquid 5, and the coating shear rate was 1.3 (1 / s). A laminate 5 was obtained in the same manner as in Example 1 except that the changes were made.
　〔非水電解液二次電池の作製〕
　積層体１の代わりに、積層体５を使用したこと以外は、実施例１と同様にして、非水電解液二次電池８を得た。その後、非水電解液二次電池８の電池特性の測定を行った。その結果を表１に示す。 [Preparation of non-aqueous electrolyte secondary battery]
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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 8 were measured. The results are shown in Table 1.
　［比較例２］
　〔多孔質層、積層体の作製〕
　無機フィラーとして、酸素原子質量百分率４４％であるマイカ（和光純薬製、商品名：非膨潤性雲母）を用いた。前記マイカを無機フィラー６とする。無機フィラー６のＤ１０、Ｄ５０、Ｄ９０は、それぞれ０．５μｍ、５．５μｍ、１２．１μｍであった。また、無機フィラー５の単位質量当たりのＢＥＴ比表面積は、３．２ｍ２／ｇであった。 [Comparative Example 2]
[Preparation of porous layer and laminate]
As the inorganic filler, mica (manufactured by Wako Pure Chemical Industries, trade name: non-swelling mica) having an oxygen atomic mass percentage of 44% was used. Let the mica be the inorganic filler 6. D10, D50, and D90 of the inorganic filler 6 were 0.5 μm, 5.5 μm, and 12.1 μm, respectively. The BET specific surface area per unit mass of the inorganic filler 5 was 3.2 m 2 / g.
　塗工液は、以下の通り作製した。すなわち、無機フィラー６（９０重量部）に対してフッ化ビニリデン－ヘキサフルオロプロピレン共重合体１０重量部を混合すると共に、無機フィラー６およびフッ化ビニリデン－ヘキサフルオロプロピレン共重合体からなる固形分の濃度が、混合液において２０重量％となるように溶媒を混合し、混合液を調製した。得られた混合液を、前記薄膜旋回型高速ミキサーで攪拌および混合して均一な塗工液を得た。当該塗工液を塗工液６とする。 The coating liquid was prepared as follows. That is, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer is mixed with inorganic filler 6 (90 parts by weight), and the solid content of inorganic filler 6 and vinylidene fluoride-hexafluoropropylene copolymer is mixed. The solvent was mixed so that the concentration of the mixed solution would be 20% by weight to prepare a mixed solution. The obtained mixed liquid was stirred and mixed by the thin film swivel type high speed mixer to obtain a uniform coating liquid. The coating liquid is referred to as coating liquid 6.
　多孔質層（Ｂ層）の作製に使用した無機フィラーを前記無機フィラー６に変更し、塗工液を前記塗工液６に変更し、塗工せん断速度を０．４（１／ｓ）に変更したこと以外は、実施例１と同様にして、積層体６を得た。 The inorganic filler used for producing the porous layer (B layer) was changed to the inorganic filler 6, the coating liquid was changed to the coating liquid 6, and the coating shear rate was 0.4 (1 / s). A layered product 6 was obtained in the same manner as in Example 1 except that it was changed.
　〔非水電解液二次電池の作製〕
　積層体１の代わりに、積層体６を使用したこと以外は、実施例１と同様にして、非水電解液二次電池９を得た。その後、非水電解液二次電池９の電池特性の測定を行った。その結果を表１に示す。 [Preparation of non-aqueous electrolyte secondary battery]
A non-aqueous electrolyte secondary battery 9 was obtained in the same manner as in Example 1 except that the laminate 6 was used instead of the laminate 1. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 9 were measured. The results are shown in Table 1.
　［比較例３］
　〔非水電解液二次電池の作製〕
　（正極板）
　正極合剤として、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｏ２／導電剤／ＰＶＤＦ（重量比：９２／５／３）を、正極集電体であるアルミニウム箔の片面に積層することにより、正極板を得た。 [Comparative Example 3]
[Preparation of non-aqueous electrolyte secondary battery]
(Positive plate)
Laminating LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio: 92/5/3) as a positive electrode mixture on one side of an aluminum foil which is a positive electrode current collector. Thus, a positive electrode plate was obtained.
　前記正極板を、正極活物質層が積層された部分の大きさが４５ｍｍ×３０ｍｍであり、かつ、その外周に、正極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、正極板４とした。正極板４の正極活物質層の厚さは３８μｍであった。 By cutting the positive electrode plate so that the size of the portion where the positive electrode active material layer is laminated is 45 mm × 30 mm, and the portion where the positive electrode active material layer is not laminated is left on its outer periphery with a width of 13 mm. , And the positive electrode plate 4. The thickness of the positive electrode active material layer of the positive electrode plate 4 was 38 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、正極板として前記正極板４を使用したこと以外は、実施例１と同様の方法にて非水電解液二次電池１０を作製した。その後、非水電解液二次電池１０の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery 10 was produced 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. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 10 were measured. The results are shown in Table 1.
　［比較例４］
　〔非水電解液二次電池の作製〕
　（負極板）
　負極合剤として、天然黒鉛／スチレン－１，３－ブタジエン共重合体／カルボキシメチルセルロースナトリウム（重量比９８／１／１）を、負極集電体である銅箔の片面に積層することにより、負極板を得た。 [Comparative Example 4]
[Preparation of non-aqueous electrolyte secondary battery]
(Negative electrode plate)
By laminating natural graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) as a negative electrode mixture on one side of a copper foil which is a negative electrode current collector, I got a board.
　前記負極板を、負極活物質層が積層された部分の大きさが５０ｍｍ×３５ｍｍであり、かつ、その外周に、負極活物質層が積層されていない部分が幅１３ｍｍで残るように切り取ることにより、負極板４とした。負極板４の負極活物質層の厚さは３８μｍであった。 By cutting the negative electrode plate so that the size of the portion where the negative electrode active material layer is laminated is 50 mm × 35 mm, and the portion where the negative electrode active material layer is not laminated remains on the outer periphery with a width of 13 mm. , And the negative electrode plate 4. The thickness of the negative electrode active material layer of the negative electrode plate 4 was 38 μm.
　（非水電解液二次電池の組み立て）
　積層体１の代わりに積層体４を使用し、正極板として前記正極板４を使用し、負極板として前記負極板４を使用したこと以外は、実施例１と同様の方法にて非水電解液二次電池１１を作製した。その後、非水電解液二次電池１１の電池特性の測定を行った。その結果を表１に示す。 (Assembly of non-aqueous electrolyte secondary battery)
Nonaqueous electrolysis was performed in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1, the positive electrode plate 4 was used as the positive electrode plate, and the negative electrode plate 4 was used as the negative electrode plate. A liquid secondary battery 11 was produced. Then, the battery characteristics of the non-aqueous electrolyte secondary battery 11 were measured. The results are shown in Table 1.
　表１において、「フィラー」は無機フィラーの種類を、「アスペクト比」は、前述した表面フィラーアスペクト比を、「ピーク強度比の最大値」は、前記式（２）で算出されるピーク強度比の最大値を、「電極活物質層が剥がれるまでの折り曲げ回数」は、前記耐折試験に供した正極板または負極板から電極活物質層が剥がれるまでの折り曲げ回数を、「１００サイクル後の充電回復容量」は、前記「１００サイクルの充放電後の充電回復容量試験」に供した非水電解液二次電池の充電回復容量を、それぞれ示す。 In Table 1, "filler" is the type of inorganic filler, "aspect ratio" is the above-described surface filler aspect ratio, and "maximum value of peak intensity ratio" is the peak intensity ratio calculated by the formula (2). The maximum value of "the number of folds until the electrode active material layer is peeled off" is the number of folds until the electrode active material layer is peeled off from the positive electrode plate or the negative electrode plate used for the folding endurance test, "charge after 100 cycles "Recovery capacity" indicates the charge recovery capacity of the non-aqueous electrolyte secondary battery subjected to the "charge recovery capacity test after 100 cycles of charge / discharge".
　また、実施例２および４～７、ならびに比較例３，４の「フィラー」欄には、二種類の化合物および数値が記載されている。当該数値は、化合物の重量部を表している。例えば、実施例２には、「Ａｌ２Ｏ３／マイカ　５０／５０」と記載されており、これは、Ａｌ２Ｏ３を５０重量部、マイカを５０重量部用いたことを表している。 Two types of compounds and numerical values are described in the "filler" column of Examples 2 and 4 to 7 and Comparative Examples 3 and 4. 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.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、実施例１～７の非水電解液二次電池は、１００サイクルの充放電後の充電回復容量が、比較例１～４の非水電解液二次電池と比較して非常に優れていた。つまり、（ｉ）「表面フィラーアスペクト比」の要件、（ｉｉ）広角Ｘ線回折法により測定した、互いに直交する任意の回折面（hkl）、（abc）のピーク強度に関する要件、および（ｉｉｉ）正極板および負極板の、前記耐折試験において電極活物質層が剥がれるまでの折り曲げ回数の要件を充足する本発明の一実施形態に係る非水電解液二次電池は、１００サイクルという多数回の充放電サイクルを経た後であっても、優れた充電回復容量を示すことが明らかとなった。 As shown in Table 1, the non-aqueous electrolyte secondary batteries of Examples 1 to 7 were compared with the non-aqueous electrolyte secondary batteries of Comparative Examples 1 to 4 in charge recovery capacity after 100 cycles of charge and discharge. Was very good. That is, (i) "surface filler aspect ratio" requirement, (ii) arbitrary diffraction planes (hkl) orthogonal to each other measured by wide-angle X-ray diffractometry, requirements regarding peak intensity of (abc), and (iii) The non-aqueous electrolyte secondary battery according to an embodiment of the present invention, which satisfies the requirement of the number of times of bending of the positive electrode plate and the negative electrode plate until the electrode active material layer is peeled off in the folding endurance test, has a large number of cycles of 100 cycles. It was revealed that even after the charge / discharge cycle, the charge recovery capacity was excellent.
　前記（ｉ）および（ｉｉ）の要件を充足することによって、多孔質層は、均一かつ緻密な構造を取るため、多孔質層におけるイオン透過性が良好な状態に維持され、多孔質層においてイオンの分布が均一となる。また、前記（ｉｉｉ）の要件を充足することによって、充放電サイクルの過程において電極活物質が膨張および収縮した場合でも、電極活物質層内部に含まれる成分である活物質、導電剤およびバインダー同士の密着性、並びに、電極活物質層と集電体との密着性が良好に維持され、電極の劣化が抑制される。その結果、（ｉ）～（ｉｉｉ）の要件を全て充足する本発明の一実施形態に係る非水電解液二次電池は、１００サイクルを経過した後であっても、充電回復容量を良好に維持することができる。 By satisfying the above requirements (i) and (ii), the porous layer has a uniform and dense structure, so that the ion permeability in the porous layer is maintained in a good state, and the ions in the porous layer are maintained. Is evenly distributed. Further, by satisfying the requirement (iii), even when the electrode active material expands and contracts in the course of the charge / discharge cycle, the active material, the conductive agent and the binder which are components contained in the electrode active material layer And the adhesion between the electrode active material layer and the current collector are maintained well, and deterioration of the electrode is suppressed. As a result, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention satisfying all the requirements (i) to (iii) has a good charge recovery capacity even after 100 cycles. Can be maintained.
　本発明の一実施形態に係る非水電解液二次電池は、多数回の充放電サイクルを経た後であっても優れた充電回復容量を示すことができるため、パーソナルコンピュータ、携帯電話および携帯情報端末などに用いる電池、並びに、車載用電池として好適に利用することができる。 The non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention can exhibit an excellent charge recovery capacity even after undergoing a large number of charge / discharge cycles, and thus can be used in personal computers, mobile phones, and portable information. It can be suitably used as a battery used for a terminal or the like, and a vehicle-mounted battery.

Claims (5)

  1. 　無機フィラーと樹脂とを含む多孔質層と、
    　ＪＩＳ　Ｐ　８１１５（１９９４）に規定されたＭＩＴ試験機法に準拠し、荷重１Ｎ、折り曲げ角度４５°にて実施した耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１３０回以上である正極板と、
    　前記耐折試験において、電極活物質層が剥がれるまでの折り曲げ回数が１６５０回以上である負極板と、を備え、
    　前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、１．４～４．０の範囲であり、
    　前記多孔質層の、広角Ｘ線回折法により測定した、互いに直交する任意の回折面（hkl）、（abc）のピーク強度：Ｉ（hkl）およびＩ（abc）が下式（１）を満たし、
    　下式（２）で算出されるピーク強度比の最大値の範囲が、１．５～３００の範囲である、非水電解液二次電池。
    　Ｉ（hkl）　＞　Ｉ（abc）・・・（１）
    　Ｉ（hkl）　／　Ｉ（abc）・・・（２）     A porous layer containing an inorganic filler and a resin,
    In a folding endurance test carried out at a load of 1 N and a bending angle of 45 ° in accordance with the MIT tester method defined in JIS P 8115 (1994), the number of times of bending until the electrode active material layer is peeled is 130 times or more. A positive electrode plate,
    In the folding endurance test, a negative electrode plate having a bending frequency of 1650 or more before the electrode active material layer is peeled off,
    The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0,
    Peak strengths of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other, measured by a wide-angle X-ray diffraction method, of the porous layer: I (hkl) and I (abc) satisfy the following formula (1). ,
    A non-aqueous electrolyte secondary battery in which the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300.
    I (hkl) > I (abc)・ ・ ・ (1)
    I (hkl) / I (abc)・ ・ ・ (2)
  2. 　前記多孔質層が、ポリオレフィン、（メタ）アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂、ポリエステル系樹脂および水溶性ポリマーからなる群より１種以上選択される樹脂を含む、請求項１に記載の非水電解液二次電池。 2. The porous layer according to claim 1, wherein the porous layer contains a resin selected from the group consisting of a polyolefin, a (meth) acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin, and a water-soluble polymer. Non-aqueous electrolyte secondary battery.
  3. 　前記ポリアミド系樹脂がアラミド樹脂である、請求項２に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 2, wherein the polyamide resin is an aramid resin.
  4. 　前記多孔質層が、ポリオレフィン多孔質フィルムの片面または両面に積層されている、請求項１～３のいずれか１項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the porous layer is laminated on one side or both sides of a polyolefin porous film.
  5. 　前記正極板が、遷移金属酸化物を含み、前記負極板が、黒鉛を含む、請求項１～４のいずれか１項に記載の非水電解液二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the positive electrode plate contains a transition metal oxide and the negative electrode plate contains graphite.
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