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WO2017033993A1 - Cell separator and method for manufacturing same - Google Patents

Cell separator and method for manufacturing same Download PDF

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Publication number
WO2017033993A1
WO2017033993A1 PCT/JP2016/074774 JP2016074774W WO2017033993A1 WO 2017033993 A1 WO2017033993 A1 WO 2017033993A1 JP 2016074774 W JP2016074774 W JP 2016074774W WO 2017033993 A1 WO2017033993 A1 WO 2017033993A1
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WO
WIPO (PCT)
Prior art keywords
plate
battery separator
substantially spherical
spherical organic
organic particles
Prior art date
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PCT/JP2016/074774
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French (fr)
Japanese (ja)
Inventor
水野　直樹
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東レバッテリーセパレータフィルム株式会社
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Application filed by 東レバッテリーセパレータフィルム株式会社 filed Critical 東レバッテリーセパレータフィルム株式会社
Priority to CN201680043565.5A priority Critical patent/CN107925034B/en
Priority to KR1020187004801A priority patent/KR102187519B1/en
Priority to JP2017536475A priority patent/JP6669174B2/en
Publication of WO2017033993A1 publication Critical patent/WO2017033993A1/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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • 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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H01M50/406—Moulding; Embossing; Cutting
    • 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
    • H01M50/417—Polyolefins
    • 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
    • H01M50/42—Acrylic 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • 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
    • H01M50/431—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
    • H01M50/409—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
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • H01M50/491—Porosity
    • 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 is a battery separator suitable for a lithium ion secondary battery having a high volumetric energy density, comprising a porous layer having adhesion to an electrode material and a polyolefin microporous film.
  • Polyolefin microporous membranes typified by polyethylene microporous membranes have excellent electrical insulation properties, ion permeability, electrolyte resistance, and oxidation resistance due to electrolyte impregnation, and an abnormal battery temperature rise of about 120 to 150 ° C.
  • the microporous membrane has a shutdown characteristic that closes the pores of the microporous membrane and cuts off the current to suppress excessive temperature rise, and is suitably used as a separator for non-aqueous electrolyte secondary batteries.
  • the viscosity of the polyolefin decreases and the microporous membrane contracts, which may cause membrane breakage of the microporous membrane.
  • lithium-ion battery separators are deeply involved in battery characteristics, battery productivity, and battery safety, and require permeability, mechanical characteristics, heat resistance, shutdown characteristics, melt-breaking characteristics (meltdown characteristics), etc.
  • improvements in adhesion to electrode materials from the viewpoint of battery cycle characteristics, and improvements in electrolyte permeability from the viewpoint of productivity have been required. Improvements in functionality are being considered.
  • the electrode body in which the negative electrode, the separator, and the positive electrode are superimposed can be filled in the container at a high density. Rather, it is predicted that a high density winding property is required.
  • Patent Document 1 in order to improve adhesion to an electrode material, a coating solution containing inorganic particles such as aluminum hydroxide oxide having an average particle diameter of 1 to 1.8 ⁇ m and an acrylic latex is used.
  • An inorganic filler layer having a thickness of 2 to 7 ⁇ m is laminated on one side of a polyolefin resin porous membrane having a thickness of 9 to 18 ⁇ m, and two types of acrylic resins having an average particle diameter of 60 to 161 nm and different glass transition temperatures (Tg) are contained on both sides.
  • Tg glass transition temperatures
  • Patent Document 2 discloses a coating solution in which a fine particle containing a vinylidene fluoride-acrylic copolymer resin having an average particle diameter of 250 nm, inorganic particles or organic particles having an average particle diameter of 200 to 1800 nm, and an aqueous emulsion is mixed with a film thickness of 9
  • the present invention assumes that the capacity of the battery will increase further in the future, and even when the battery separator is thinned, it has adhesiveness with the electrode material and unnecessary space between the electrode material and the separator. Aiming to provide a battery separator particularly suitable for lithium ion secondary battery separators, which can increase the number of windings and the number of layers of the electrode body by minimizing the number of electrodes and obtain an electrode body with a high volume energy density. It is a thing.
  • the battery separator of the present invention has the following configuration. That is, (1) It has a polyolefin microporous film, and a substantially spherical organic particle made of an acrylic resin or a fluorine resin and a porous layer containing a plate-like inorganic particle on at least one surface, and the substantially spherical organic particle is in the film thickness direction.
  • the ratio (r / t) between the average particle diameter r ( ⁇ m) of the substantially spherical organic particles and the average thickness t ( ⁇ m) of the plate-like inorganic particles is Satisfactory battery separator. 0.1 ⁇ m ⁇ r ⁇ 0.8 ⁇ m ...
  • the plate-like inorganic particles are preferably alumina or boehmite.
  • the volume of the substantially spherical organic particles is preferably 10 to 30% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles.
  • the battery separator of the present invention is preferably a lithium ion secondary battery separator.
  • the battery separator manufacturing method of the present invention has the following configuration. That is, (5) A battery separator manufacturing method including the following steps (a) and (b) in sequence.
  • the viscosity of the coating liquid A is preferably 10 to 30 mPa ⁇ s.
  • the viscosity of the coating liquid B is preferably 1 to 10 mPa ⁇ s.
  • the present invention assumes that the capacity of the battery will increase further in the future, and even when the battery separator is thinned, it has adhesiveness with the electrode material and unnecessary space between the electrode material and the separator. It is a battery separator particularly suitable for a lithium ion secondary battery separator, which can increase the number of windings and the number of laminated layers of the electrode body by minimizing the amount of electrode and obtain an electrode body having a high volume energy density.
  • the polyolefin microporous membrane preferably contains a polyolefin resin having a melting point (softening point) of 70 to 150 ° C. from the viewpoint of the function of blocking the pores when the charge / discharge reaction is abnormal.
  • the polyolefin resin may be a single substance such as polyethylene or polypropylene, a mixture thereof, a mixture of two or more different polyolefin resins, or a copolymer of different olefins.
  • polyethylene resin is preferable from the viewpoint of the function of blocking the pores.
  • the polyolefin microporous film may be a single layer or a multilayer film composed of two or more layers having different molecular weights or average pore diameters.
  • a method for producing a multilayer film composed of two or more layers for example, the polyolefin resin constituting the A1 layer or the A2 layer is melt-kneaded with a film-forming solvent, and the resulting molten mixture is sent from each extruder to one die. It is possible to produce either a method in which gel sheets constituting each component are integrated and co-extruded or a method in which gel sheets constituting each layer are superposed and heat-sealed.
  • the coextrusion method is more preferable because it is easy to obtain a high interlayer adhesive strength, and it is easy to form communication holes between layers, so that high permeability is easily maintained and productivity is excellent.
  • the film thickness of the polyolefin microporous membrane is preferably 3 ⁇ m or more and less than 10 ⁇ m, more preferably 5 ⁇ m or more and less than 9.0 ⁇ m, and even more preferably 6 ⁇ m or more and 8 ⁇ m, from the viewpoint of increasing the volume energy of the battery that will be advanced in the future. Is less than.
  • the average pore diameter of the polyolefin microporous membrane is 0.01 to 1.0 ⁇ m, preferably 0.05 to 0.5 ⁇ m, more preferably 0.1 to 0.3 ⁇ m, from the viewpoint of the pore closing speed and the pore closing temperature. .
  • the average pore diameter of the polyolefin microporous membrane is within the above-mentioned preferable range, the anchoring effect by the resin of the porous layer can be obtained without significantly deteriorating the air resistance when the porous layer is laminated.
  • the air permeability resistance of the polyolefin microporous membrane is preferably 50 to 500 sec / 100 cc Air.
  • the porosity of the polyolefin microporous membrane is preferably 30 to 70%.
  • the porous layer includes plate-like inorganic particles and substantially spherical organic particles.
  • the plate-like inorganic particles play a role of reinforcing the polyolefin microporous membrane by its heat resistance and improving the melt-breaking properties.
  • the substantially spherical organic particles play a role of improving the adhesion with the electrode material and improving the cycle characteristics when incorporated in a battery.
  • the porous layer is formed by sequentially applying a coating liquid A containing plate-like inorganic particles and a coating liquid B containing substantially spherical organic particles to a polyolefin microporous film.
  • the coating liquid A contains plate-like inorganic particles and a dispersion medium, and may contain a binder as necessary.
  • the material of the plate-like inorganic particles is not particularly limited, but alumina, boehmite, and mica are relatively easily available and suitable.
  • boehmite is preferable from the viewpoint that the hardness is low and wear of a coating roll or the like can be suppressed.
  • plate-like inorganic particles refers to particles having an aspect ratio (major axis / thickness) of 1.5 or more and a major axis / minor axis ratio of 1 to 10.
  • the lower limit of the aspect ratio of the plate-like inorganic particles is preferably 2, more preferably 3, and still more preferably 5.
  • the upper limit is preferably 50, more preferably 20, and even more preferably 10.
  • the average particle size (average major axis) of the plate-like inorganic particles is preferably 0.5 ⁇ m to 2.0 ⁇ m, and the average thickness is preferably 0.1 ⁇ m or more and less than 0.5 ⁇ m.
  • the plate-like inorganic particles can be easily arranged in a direction substantially parallel to the plane direction of the polyolefin microporous membrane.
  • the porous layer can be filled with a relatively high density, and generation of coarse voids and surface protrusions exceeding 1 ⁇ m in size can be suppressed in the porous layer.
  • the average value of the ratio of the long axis direction length to the short axis direction length (major axis / minor axis) of the plate-like inorganic particles is preferably 3 or less, more preferably 2 or less and a value close to 1. .
  • the binder is not particularly limited as long as it provides the adhesion between the polyolefin microporous membrane and the porous layer and adheres the plate-like inorganic particles.
  • a water-soluble resin or a water-dispersible resin is preferable.
  • the water-soluble resin or water-dispersible resin include acrylic resins such as polyvinyl alcohol, polyacrylic acid, polyacrylamide, and polymethacrylic acid.
  • polyvinyl alcohol and acrylic resin are preferable.
  • acrylic resin commercially available acrylic emulsions can be used. For example, “Acryset” (registered trademark) TF-300 manufactured by Nippon Shokubai Co., Ltd., “Polysol” (registered trademark) AP manufactured by Showa Denko K.K. -4735.
  • the dispersion medium of the coating liquid A contains water as a main component, and ethyl alcohol, butyl alcohol, or the like may be added to improve the coating property. Furthermore, you may add a binder, a dispersing agent, and a thickener as needed.
  • the viscosity of the coating liquid A is preferably 10 to 30 mPa ⁇ s, more preferably 12 to 25 mPa ⁇ s, and still more preferably 15 to 25 mPa ⁇ s.
  • the content of the plate-like inorganic particles in the coating liquid A is preferably 40 to 60% by mass. When the viscosity of the coating liquid A and the content of the plate-like inorganic particles are within the above preferable ranges, the plate-like inorganic particles can be made substantially parallel to the plane direction of the polyolefin microporous membrane.
  • the coating amount is preferably 1 g / m 2 or more and 3 g / m 2 or less in consideration of the volume energy density when the wound body is used as a film breaking strength or an electrode body.
  • the coating liquid B contains substantially spherical organic particles and a dispersion medium, and may contain a binder as necessary.
  • the circularity of the substantially spherical organic particles is 0.97 or more, preferably 0.98 or more, and most preferably 0.99 to 1.00.
  • L0 in the above equation is the perimeter of an ideal circle (perfect circle) having the same area as the area calculated from the projection image (particle image) of the target particle actually measured, and L1 is the measurement. This is the actual perimeter measured from the particle projection image (particle image) of the target particle.
  • the lower limit of the average particle diameter (r) of the substantially spherical organic particles is preferably 0.1 ⁇ m, more preferably 0.2 ⁇ m, and still more preferably 0.3 ⁇ m.
  • the upper limit is preferably 0.8 ⁇ m, more preferably 0.7 ⁇ m, and even more preferably 0.6 ⁇ m. If the average particle size (r) is less than 0.1 ⁇ m, it may penetrate into the gaps between the plate-like inorganic particles as far as possible, and may not sufficiently contribute to the improvement in adhesion to the electrode material. If it exceeds 0.8 ⁇ m, it tends to fall off, which is not preferable.
  • the substantially spherical organic particles preferably contain a fluorine resin, an acrylic resin, or both.
  • the fluororesin is at least one selected from the group consisting of vinylidene fluoride homopolymers, vinylidene fluoride / fluorinated olefin copolymers, vinyl fluoride homopolymers, and vinyl fluoride / fluorinated olefin copolymers. Can be used.
  • a vinylidene fluoride / hexafluoropropylene copolymer is preferable from the viewpoint of adhesion to an electrode material.
  • the mol% of hexafluoropropylene is more preferably 1 to 3 mol%.
  • This polymer has excellent adhesion to electrode materials, moderate swelling with non-aqueous electrolytes, and high chemical and physical stability against non-aqueous electrolytes. Affinity with the electrolytic solution can be sufficiently maintained even when used in
  • fluororesin a commercially available fluororesin can be used after being refined into a spherical shape if necessary.
  • examples of commercially available fluororesins include KYNAR FREX (registered trademark) 2851-00, 2801-00, 2821-00, 2501-20 and the like manufactured by ARKEMA.
  • the acrylic resin is not particularly limited as long as it has adhesiveness with the electrode material, but a resin obtained by polymerizing an acrylate monomer is preferable.
  • the acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl meth (acrylate), isopyl pill (meth) acrylate, n-butyl (meth) acrylate, and t-butyl (meth) acrylate.
  • De port carboxymethyl group-containing (meth) acrylate De port carboxymethyl group-containing (meth) acrylate.
  • a coating liquid in which commercially available acrylic resin particles are dispersed may be used.
  • examples of the coating liquid in which commercially available acrylic resin particles are dispersed include ASR latex product name: TRD202A manufactured by JSR Corporation.
  • Non-crosslinked organic particles are preferred from the viewpoint of adhesion to the electrode material.
  • the dispersion medium of the coating liquid B contains water as a main component, and ethyl alcohol, butyl alcohol, or the like may be added as necessary in order to improve coating properties. Furthermore, you may add a binder, a dispersing agent, and a thickener as needed.
  • the binder is not particularly limited as long as it imparts adhesion between the polyolefin microporous membrane and the porous layer and adheres substantially spherical organic particles.
  • the same binder as the first layer can be used.
  • the viscosity of the coating liquid B is preferably 1 to 10 mPa ⁇ s, more preferably 2 to 8 mPa ⁇ s, and further preferably 3 to 6 mPa ⁇ s.
  • the content of the substantially spherical organic particles in the coating liquid B is preferably 3 to 10% by mass.
  • the substantially spherical organic particles roll on the plate-like inorganic particles, and the surface recesses between the plate-like inorganic particles are likely to enter. As shown in 1 and 2, it becomes easy to obtain a sea-island structure state of aggregates of substantially spherical organic particles and plate-like inorganic particles.
  • the volume of the substantially spherical organic particles is preferably 10 to 30% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. If it is 10 volume% or more, the function which provides or improves the adhesiveness with an electrode material will be easy to be obtained. If it is 30% by volume or less, a relatively large content of the plate-like inorganic particles can be maintained, and sufficient film breaking strength can be easily obtained.
  • the ratio (r / t) of the average particle diameter r ( ⁇ m) of the substantially spherical organic particles to the average thickness t ( ⁇ m) of the plate-like inorganic particles is set within the range of 0.3 ⁇ r / t ⁇ 1.0. is important. Within the above preferable range, when the coating liquid B is applied to the plate-like inorganic particle layer, the substantially spherical organic particles roll on the surface of the plate-like inorganic particle layer and easily enter the recesses of the plate-like inorganic particle layer.
  • the cross section of the porous layer has a form in which the substantially spherical organic particles enter the recesses on the surface of the plate-like inorganic particle layer so as to have adhesiveness with the electrode (see FIG. 1).
  • the surface of the porous layer is magnified, almost spherical organic particles are present so as to fill the recesses on the surface of the plate-like inorganic particle layer, and an aggregate of plate-like inorganic particles and spherical organic particles is observed. It has a form (see FIG. 2).
  • FIG. 2 shows an example in which the plate-like inorganic particles are islands and the aggregate of spherical organic particles is the sea.
  • the porous layer has a sea-island structure, the adhesion with the electrode material can be improved while suppressing an increase in the thickness of the porous layer. If it is strong, it leads to the improvement of the volume energy density of the battery obtained.
  • the thickness of the porous layer varies depending on the intended use of the obtained battery, but is preferably 0.5 to 2.5 ⁇ m, more preferably 0.8 to 2.2 ⁇ m, and still more preferably 1.0 to 2.0 ⁇ m. is there. Adhesiveness with an electrode material can be provided or improved as the film thickness of the porous layer is within the above preferred range.
  • the membrane breaking strength when the polyolefin microporous membrane is melted / shrinked at a temperature equal to or higher than the melting point of the polyolefin can be maintained, and insulation can be secured. Further, a high volume energy density can be obtained when a wound body is used as the electrode body.
  • the porosity of the porous layer is preferably 30 to 90% from the viewpoint of the electric resistance and film strength of the film.
  • the air resistance of the porous layer is preferably 1 to 600 sec / 100 cc Air measured by a method based on JIS P 8117 from the viewpoint of film strength and cycle characteristics.
  • the battery separator of the present invention is obtained by applying a coating liquid A containing plate-like inorganic particles and a coating liquid B containing substantially spherical organic particles to a polyolefin microporous film.
  • the coating liquid A is applied to the polyolefin microporous membrane so that the plate-like inorganic particles are substantially parallel to the polyolefin microporous membrane, and dried to form a plate-like inorganic particle layer.
  • the direction of the plate-like inorganic particles becomes irregular, and voids exceeding 1 ⁇ m in size are easily formed in the porous layer, and plate-like inorganic particles that are not substantially parallel are easily generated as protrusions on the surface, and the electrode body. As a result, voids are likely to occur.
  • the coating liquid B may be applied only on the plate-like inorganic particle layer, or may be applied to the other surface of the polyolefin microporous film not provided with the plate-like inorganic particle layer. In order to obtain adhesiveness with the electrode material, it is sufficient that the substantially spherical organic particles of the coating liquid B can be applied so as to be unevenly distributed on the surface.
  • a well-known method can be adopted as the wet coating method.
  • examples thereof include a roll coating method, a gravure coating method, a kiss coating method, a dip coating method, a spray coating method, an air knife coating method, a Meyer bar coating method, a pipe doctor method, a blade coating method, and a die coating method.
  • a method of applying a relatively strong shearing force to the coating solution on the polyolefin microporous film is preferable, and among the roll coating method and the gravure coating method, the reverse roll coating method and the reverse gravure coating method are preferable.
  • the rotation direction of the coating roll relative to the traveling direction of the polyolefin microporous membrane is opposite, so that a strong shearing force can be applied to the coating liquid, and the plate-like inorganic particles are applied to the polyolefin microporous membrane. It can be made to be substantially parallel to it.
  • the ratio between the conveying speed (F) of the polyolefin microporous membrane and the peripheral speed (S) of the coating roll rotating in reverse (hereinafter abbreviated as S / F ratio) is preferably 1.02 or more.
  • a more preferred lower limit is 1.05, and even more preferably 1.07. If it is 1.02 or more, a sufficient shearing force can be applied to the coating solution.
  • the upper limit is not particularly defined but can be 1.20.
  • the total thickness of the battery separator is preferably 6 to 13 ⁇ m, more preferably 7 to 12 ⁇ m, from the viewpoint of mechanical strength and insulation. Also, a high volume energy density can be obtained when a wound body is used as the electrode body.
  • the measured value in an Example is a value measured with the following method.
  • the obtained sample was observed by SEM at a magnification of 20,000 times.
  • Arbitrary 20 particles were selected on the image obtained by SEM measurement, and the average value of the particle diameters of the 20 particles was defined as the average particle diameter of the substantially spherical organic particles.
  • Average particle size of the plate-like inorganic particles From among the images obtained by the SEM measurement used in the above 3, arbitrary 20 particles whose planar shape is observed on the image are selected with respect to the double-sided tape. The average value of the length of the major axis was taken as the average particle size of the plate-like inorganic particles.
  • Film thickness Measured using a contact-type film thickness meter Digital Micrometer M-30 manufactured by Sony Manufacturing Systems Co., Ltd..
  • the layer coat electrode A100 (1.6mAh / cm ⁇ 2 >) by the Piotrec company company was used as a negative electrode.
  • ⁇ Active material of negative electrode adheres to modified porous layer of battery separator in an area ratio of less than 30%
  • meltdown characteristics While the separators obtained in the examples and comparative examples were heated at a rate of temperature increase of 5 ° C./min, the air resistance was measured with an Oken type air resistance meter (Asahi Seiko Co., Ltd., EGO-1T). Then, after the air resistance reached the detection limit of 1 ⁇ 10 5 sec / 100 cc, the temperature at which the air resistance began to drop again to 1 ⁇ 10 5 sec / 100 cc or less was obtained and was defined as the meltdown temperature (° C.). When the judgment meltdown temperature (° C) exceeds 200 ° C When the meltdown temperature (° C) is 200 ° C or lower ⁇ ⁇
  • Viscosity of coating liquid The viscosity of the coating liquid at 25 ° C. was measured using a viscometer (DV-I PRIME manufactured by BROOKFIELD).
  • Example 1 (Preparation of coating solution A) 40 parts by weight of a mixture of 58 parts by weight of ion-exchanged water and 1 part by weight of butanol (plate boehmite having an average particle diameter of 1.0 ⁇ m and an average thickness of 0.4 ⁇ m, major axis / minor axis ratio of 2) and Ken as a binder 1 part by mass of 95% of polyvinyl alcohol was added and dispersed well. Subsequently, carboxymethylcellulose (CMC) was added as a thickener, and the liquid viscosity was adjusted to 20 mPa ⁇ s to obtain a coating liquid A1.
  • CMC carboxymethylcellulose
  • Example 2 The same procedure as in Example 1 was conducted except that coating liquid A2 in the form of plate-like boehmite particles (average particle size 2.0 ⁇ m, average thickness 0.4 ⁇ m, major axis / minor axis ratio 3) was used instead of plate-like boehmite. A battery separator was obtained.
  • Example 3 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A3 having a liquid viscosity adjusted to 10 mPa ⁇ s was used.
  • Example 4 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A4 having a liquid viscosity adjusted to 30 mPa ⁇ s was used.
  • Example 5 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A5 having an average particle size of 1.0 ⁇ m, an average thickness of 0.2 ⁇ m, and a major axis / minor axis ratio of 3 was used. .
  • Example 6 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A6 having an average particle size of 2.0 ⁇ m, an average thickness of 0.6 ⁇ m, and a major axis / minor axis ratio of 3 was used for the plate-like boehmite particles.
  • Example 7 The same procedure as in Example 1 was performed except that the coating amount of the coating liquid B was adjusted so that the volume of the substantially spherical organic particles was 25% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. Thus, a battery separator was obtained.
  • Example 8 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A was applied under conditions of an S / F ratio of 1.18.
  • Example 9 In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B2 having a liquid viscosity adjusted to 10 mPa ⁇ s was used.
  • Example 10 In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B3 having a liquid viscosity adjusted to 2 mPa ⁇ s was used.
  • Comparative Example 1 (Preparation of coating solution) 40 parts by mass of plate boehmite having an average particle diameter of 1.0 ⁇ m and an average thickness of 0.4 ⁇ m in a mixed solution composed of 58 parts by mass of ion-exchanged water and 1 part by mass of butanol, and 1 mass of polyvinyl alcohol having a saponification degree of 95% as a binder And a substantially spherical organic particle dispersion liquid (TRD202A manufactured by JSR Corporation, solid content concentration 40% by mass) made of an acrylic resin having an average particle size of 0.2 ⁇ m with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles Then, it was added so that the volume of the substantially spherical organic particles was 15% by volume and well dispersed.
  • TRD202A manufactured by JSR Corporation, solid content concentration 40% by mass
  • Carboxymethylcellulose (CMC) was added as a thickener to this dispersion, and the liquid viscosity was adjusted to 20 mPa ⁇ s to obtain a coating liquid C.
  • a coating device reverse gravure coating method shown in FIG. 3 on a polyethylene microporous membrane (thickness 7 ⁇ m, porosity 21%, air permeability 120 seconds / 100 cc)
  • a conveyance speed of 30 m / min S / F Coating and drying were performed under the condition of a ratio of 1.05, and a porous layer was laminated to obtain a battery separator.
  • the basis weight when the porous layer was dried was 2.7 g / m 2 .
  • Comparative Example 2 In the preparation of the coating liquid A, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid A7 in which alumina particles having an average particle diameter of 0.4 ⁇ m were used instead of the plate boehmite was used.
  • Comparative Example 3 In the preparation of the coating liquid A, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid A8 having a liquid viscosity adjusted to 8 mPa ⁇ s was used.
  • Comparative Example 4 In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B4 having a liquid viscosity adjusted to 20 mPa ⁇ s was used.
  • Comparative Example 5 In the preparation of the coating liquid B, a coating liquid B5 obtained by replacing the substantially spherical organic particle dispersion with an aqueous dispersion (solid content concentration 15% by mass) of melamine / formaldehyde condensate spherical particles (average particle size 0.4 ⁇ m) is used. A battery separator was obtained in the same manner as in Example 1 except that it was used.
  • Comparative Example 6 The same procedure as in Example 1 was conducted except that the coating amount of the coating liquid B was adjusted so that the volume of the substantially spherical organic particles was 5% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. Thus, a battery separator was obtained.
  • Comparative Example 7 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A was applied under conditions of an S / F ratio of 0.50.
  • Comparative Example 8 Similar to Example 1 except that the rotation direction of the gravure roll is the same as the transport direction of the polyethylene microporous membrane when the coating liquid A1 is applied, and the coating liquid A1 is applied under the condition of S / F ratio of 1.25. Thus, a battery separator was obtained.
  • Comparative Example 9 A polyethylene microporous membrane (porosity 23%, air permeability 110 seconds / 100 cc) having the same thickness as the battery separator of Comparative Example 1 was used as the battery separator.
  • Table 1 shows the characteristics of the battery separators obtained in Examples 1 to 10 and Comparative Examples 1 to 9.
  • Table 1 shows the characteristics of the battery separators obtained in Examples 1 to 10 and Comparative Examples 1 to 9.
  • Example 1 to 10 and Comparative Examples 3 and 5 to 7 substantially spherical organic particles are unevenly distributed on the surface of the porous layer, and the plate-like inorganic particles are islands. It was a sea-island structure with substantially spherical organic particles as the sea.
  • Comparative Examples 1 and 4 plate-like inorganic particles and substantially spherical organic particles were mixed, and the sea-island structure was not obtained.

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Abstract

The present inventor, surmising that cell separators will continue become thinner and increase in capacitance, provides a cell separator having adhesiveness with an electrode material and that is capable of minimizing wasted space between an electrode material and a separator, and provides a cell separator in which high volume energy density can be obtained when the electrode material and separator are superimposed and formed into a wound body, and which is particularly advantageous for a lithium-ion cell separator. A cell separator in which a porous layer containing a polyolefin microporous film, and plate-shaped inorganic particles and substantially spherical organic particles composed of an acrylic resin or fluororesin are layered on the surface of the film, the substantially spherical organic particles are unevenly distributed on the surface of the porous layer, and the ratio of the average particle diameter r (µm) of the substantially spherical organic particles and the average thickness t (µm) of the plate-shaped inorganic particles satisfies formulas 1 and 2. 0.1 µm ≦ r ≦ 0.8 µm... Formula 1 0.3 ≦ r/t ≦ 1.0... Formula 2

Description

電池用セパレータおよびその製造方法Battery separator and method for producing the same
　本発明は電極材料との密着性を有する多孔層とポリオレフィン微多孔膜からなる、体積エネルギー密度の高いリチウムイオン二次電池に適した電池用セパレータである。 The present invention is a battery separator suitable for a lithium ion secondary battery having a high volumetric energy density, comprising a porous layer having adhesion to an electrode material and a polyolefin microporous film.
　ポリエチレン微多孔膜に代表されるポリオレフィン微多孔膜は、電気絶縁性、電解液含浸によりイオン透過性、耐電解液性、耐酸化性などに優れ、さらに約１２０～１５０℃という電池の異常昇温時において微多孔膜の細孔を閉塞し、電流を遮断することで過度の昇温を抑制するシャットダウン特性を備えており、非水電解質二次電池用セパレータとして好適に使用されている。しかしながら、何らかの原因でシャットダウン後も電池の昇温が続く場合、ポリオレフィンの粘度が低下し、微多孔膜が収縮することで微多孔膜の破膜を生じることがある。 Polyolefin microporous membranes typified by polyethylene microporous membranes have excellent electrical insulation properties, ion permeability, electrolyte resistance, and oxidation resistance due to electrolyte impregnation, and an abnormal battery temperature rise of about 120 to 150 ° C. At the time, the microporous membrane has a shutdown characteristic that closes the pores of the microporous membrane and cuts off the current to suppress excessive temperature rise, and is suitably used as a separator for non-aqueous electrolyte secondary batteries. However, when the temperature of the battery continues to rise even after shutdown for some reason, the viscosity of the polyolefin decreases and the microporous membrane contracts, which may cause membrane breakage of the microporous membrane.
　特に、リチウムイオン電池用セパレータは電池特性、電池生産性及び電池安全性に深く関わっており、透過性、機械的特性、耐熱性、シャットダウン特性、溶融破膜特性（メルトダウン特性）等が要求される。近年では、電池のサイクル特性の観点から電極材料との密着性の向上、生産性の観点からは電解液浸透性の向上などが要求され、これまでに微多孔膜に多孔層を設けることでこれら機能を向上させることが検討されている。 In particular, lithium-ion battery separators are deeply involved in battery characteristics, battery productivity, and battery safety, and require permeability, mechanical characteristics, heat resistance, shutdown characteristics, melt-breaking characteristics (meltdown characteristics), etc. The In recent years, improvements in adhesion to electrode materials from the viewpoint of battery cycle characteristics, and improvements in electrolyte permeability from the viewpoint of productivity have been required. Improvements in functionality are being considered.
　さらに、捲回型電池においては体積エネルギー密度の向上のため、負極、セパレータ、正極を重ね合わせた電極体を高密度に容器内に充填できることが望まれており、今後、セパレータには薄膜化のみならず、高密度の捲回性が要求されることが予測される。 Furthermore, in order to improve the volumetric energy density of wound type batteries, it is desired that the electrode body in which the negative electrode, the separator, and the positive electrode are superimposed can be filled in the container at a high density. Rather, it is predicted that a high density winding property is required.
　特許文献１には、電極材料との接着性を向上させるために、平均粒径１～１．８μｍの水酸化酸化アルミニウムなどの無機粒子と、アクリル系ラテックスを含む塗布液を用いて、厚さ９～１８μｍのポリオレフィン樹脂多孔膜の片面に厚さ２～７μｍの無機フィラー層を積層し、その両面に平均粒径６０～１６１ｎｍでガラス転移温度（Ｔｇ）の異なる２種のアクリル系樹脂を含むラテックスをドット状に形成させた蓄電デバイス用セパレータが例示されている。 In Patent Document 1, in order to improve adhesion to an electrode material, a coating solution containing inorganic particles such as aluminum hydroxide oxide having an average particle diameter of 1 to 1.8 μm and an acrylic latex is used. An inorganic filler layer having a thickness of 2 to 7 μm is laminated on one side of a polyolefin resin porous membrane having a thickness of 9 to 18 μm, and two types of acrylic resins having an average particle diameter of 60 to 161 nm and different glass transition temperatures (Tg) are contained on both sides. A separator for an electricity storage device in which latex is formed in a dot shape is illustrated.
　特許文献２には、平均粒径２５０ｎｍのフッ化ビニリデン－アクリル共重体樹脂を含む微粒子と、平均粒径２００～１８００ｎｍの無機粒子または有機粒子と、水系エマルジョンを混合した塗工液を膜厚９～１２μｍのポリオレフィン微多孔膜の両面に塗工厚１．３～１５μｍで積層した非水系二次電池用セパレータを例示されている。 Patent Document 2 discloses a coating solution in which a fine particle containing a vinylidene fluoride-acrylic copolymer resin having an average particle diameter of 250 nm, inorganic particles or organic particles having an average particle diameter of 200 to 1800 nm, and an aqueous emulsion is mixed with a film thickness of 9 A separator for a non-aqueous secondary battery in which a coating thickness of 1.3 to 15 μm is laminated on both sides of a polyolefin microporous membrane of ˜12 μm is exemplified.
　ポリオレフィン微多孔膜と多孔層を備えた電池用セパレータにおいて、溶融破膜特性や電極材料との接着性を付与または向上させるためにこれら機能を多孔層に持たせた場合、多孔層の厚みを厚くするほどその機能は十分に発揮される。一方で、多孔層の厚みを厚くすることで高密度の捲回が難しくなり捲回型電池の体積エネルギー密度が低下するといった問題が生じる。すなわち、多孔層に求める機能と高密度の捲回性とは二律背反の関係にあると言っても過言ではない。　　　 In battery separators equipped with a polyolefin microporous membrane and a porous layer, if these functions are given to the porous layer in order to impart or improve melt-breaking properties and adhesion to electrode materials, the thickness of the porous layer is increased. The function is fully demonstrated so as to do. On the other hand, increasing the thickness of the porous layer makes it difficult to wind at a high density, resulting in a problem that the volume energy density of the wound battery decreases. That is, it is not an exaggeration to say that the function required for the porous layer and the high density winding property are in contradiction. *
国際公開２０１４／０１７６５１号International Publication No. 2014/017651 国際公開２０１３／１３３０７４号International Publication No. 2013/133704
　本発明は今後ますます電池の高容量化が進んだ場合を想定し、電池用セパレータを薄膜化した場合においても電極材料との接着性を有し、かつ、電極材料とセパレータ間の不要な空間を最小限にすることで電極体の巻き数、積層数を増加させ、高い体積エネルギー密度の電極体を得ることができる、特にリチウムイオン二次電池用セパレータに好適な電池用セパレータの提供を目指したものである。 The present invention assumes that the capacity of the battery will increase further in the future, and even when the battery separator is thinned, it has adhesiveness with the electrode material and unnecessary space between the electrode material and the separator. Aiming to provide a battery separator particularly suitable for lithium ion secondary battery separators, which can increase the number of windings and the number of layers of the electrode body by minimizing the number of electrodes and obtain an electrode body with a high volume energy density. It is a thing.
　上記課題を解決するために本発明の電池用セパレータは以下の構成を有する。
すなわち、
（１）ポリオレフィン微多孔膜と、少なくともその片面にアクリル系樹脂またはフッ素系樹脂からなる略球状有機粒子と板状無機粒子を含む多孔層とを有し、略球状有機粒子が膜厚方向に対して多孔層の表面に偏在しており、略球状有機粒子の平均粒径ｒ（μｍ）と板状無機粒子の平均厚さｔ（μｍ）の比（ｒ／ｔ）が式１及び式２を満足する電池用セパレータ、である。
　　０．１μｍ≦ｒ≦０．８μｍ・・・・式１
　　０．３≦ｒ／ｔ≦１．０　　・・・・式２　　
（２）本発明の電池用セパレータは、板状無機粒子はアルミナまたはベーマイトであることが好ましい。
（３）本発明の電池用セパレータは、略球状有機粒子の体積が略球状有機粒子と板状無機粒子の総体積に対して１０～３０体積％であることが好ましい。
（４）本発明の電池用セパレータは、リチウムイオン二次電池用セパレータであることが好ましい。
　上記課題を解決するために本発明の電池用セパレータの製造方法は以下の構成を有する。
すなわち、
（５）以下の工程（ａ）及び（ｂ）を順次含む電池用セパレータの製造方法、である。
　（ａ）ポリオレフィン微多孔膜に板状無機粒子を含む塗工液Ａをリバースグラビアコート法で塗布し、乾燥させ、板状無機粒子層を積層させる工程。
　（ｂ）板状無機粒子層上にアクリル系樹脂またはフッ素系樹脂からなる略球状有機粒子を含む塗工液Ｂをリバースグラビアコート法で塗布し、乾燥させ電池用セパレータを得る工程。
（６）本発明の電池用セパレータの製造方法は、塗工液Ａの粘度が１０～３０ｍＰａ・ｓであることが好ましい。
（７）本発明の電池用セパレータの製造方法は、塗工液Ｂの粘度が１～１０ｍＰａ・ｓであることが好ましい。 In order to solve the above problems, the battery separator of the present invention has the following configuration.
That is,
(1) It has a polyolefin microporous film, and a substantially spherical organic particle made of an acrylic resin or a fluorine resin and a porous layer containing a plate-like inorganic particle on at least one surface, and the substantially spherical organic particle is in the film thickness direction. The ratio (r / t) between the average particle diameter r (μm) of the substantially spherical organic particles and the average thickness t (μm) of the plate-like inorganic particles is Satisfactory battery separator.
0.1 μm ≦ r ≦ 0.8 μm ... Formula 1
0.3 ≦ r / t ≦ 1.0 Formula 2
(2) In the battery separator of the present invention, the plate-like inorganic particles are preferably alumina or boehmite.
(3) In the battery separator of the present invention, the volume of the substantially spherical organic particles is preferably 10 to 30% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles.
(4) The battery separator of the present invention is preferably a lithium ion secondary battery separator.
In order to solve the above-described problems, the battery separator manufacturing method of the present invention has the following configuration.
That is,
(5) A battery separator manufacturing method including the following steps (a) and (b) in sequence.
(A) The process of apply | coating the coating liquid A containing a plate-shaped inorganic particle to a polyolefin microporous film by a reverse gravure coating method, and making it dry and laminating | stack a plate-shaped inorganic particle layer.
(B) The process of apply | coating the coating liquid B containing the substantially spherical organic particle which consists of an acrylic resin or a fluorine resin on a plate-shaped inorganic particle layer by a reverse gravure coating method, and obtaining a battery separator.
(6) In the method for producing a battery separator of the present invention, the viscosity of the coating liquid A is preferably 10 to 30 mPa · s.
(7) In the method for producing a battery separator of the present invention, the viscosity of the coating liquid B is preferably 1 to 10 mPa · s.
　本発明は今後ますます電池の高容量化が進んだ場合を想定し、電池用セパレータを薄膜化した場合においても電極材料との接着性を有し、かつ、電極材料とセパレータ間の不要な空間を最小限にすることで電極体の巻き数、積層数を増加させ、高い体積エネルギー密度の電極体を得ることができる、特にリチウムイオン二次電池用セパレータに好適な電池用セパレータである。 The present invention assumes that the capacity of the battery will increase further in the future, and even when the battery separator is thinned, it has adhesiveness with the electrode material and unnecessary space between the electrode material and the separator. It is a battery separator particularly suitable for a lithium ion secondary battery separator, which can increase the number of windings and the number of laminated layers of the electrode body by minimizing the amount of electrode and obtain an electrode body having a high volume energy density.
本発明のセパレータの断面拡大模式図である。It is a cross-sectional enlarged schematic diagram of the separator of this invention. 本発明のセパレータにおける多孔層表面の拡大模式図である。It is an expansion schematic diagram of the porous layer surface in the separator of this invention. 本発明に用いる塗工装置の概略図である。It is the schematic of the coating apparatus used for this invention.
１．ポリオレフィン微多孔膜
　まず、本発明で用いるポリオレフィン微多孔膜について説明する。
　ポリオレフィン微多孔膜は、充放電反応の異常時に孔が閉塞する機能の観点から、融点（軟化点）が７０～１５０℃のポリオレフィン樹脂を含有することが好ましい。ポリオレフィン樹脂は、ポリエチレンやポリプロピレンなどの単一物、これらの混合物、２種以上の異なるポリオレフィン樹脂の混合物、又は異なるオレフィンの共重合体であってもよい。特に、孔が閉塞する機能の観点からポリエチレン樹脂が好ましい。 1. Polyolefin microporous membrane First, the polyolefin microporous membrane used in the present invention will be described.
The polyolefin microporous membrane preferably contains a polyolefin resin having a melting point (softening point) of 70 to 150 ° C. from the viewpoint of the function of blocking the pores when the charge / discharge reaction is abnormal. The polyolefin resin may be a single substance such as polyethylene or polypropylene, a mixture thereof, a mixture of two or more different polyolefin resins, or a copolymer of different olefins. In particular, polyethylene resin is preferable from the viewpoint of the function of blocking the pores.
　ポリオレフィン微多孔膜は、単層であってもよいし、分子量あるいは平均細孔径の異なる二層以上からなる多層膜であってもよい。二層以上からなる多層膜の製造方法としては、例えば、Ａ１層またはＡ２層を構成するポリオレフィン樹脂をそれぞれ成膜用溶剤と溶融混練し、得られた溶融混合物をそれぞれの押出機から１つのダイに供給し各成分を構成するゲルシートを一体化させて共押出する方法や、各層を構成するゲルシートを重ね合わせて熱融着する方法のいずれでも作製できる。共押出法の方が、高い層間接着強度を得やすく、層間に連通孔を形成しやすいために高透過性を維持しやすく、生産性にも優れているためにより好ましい。 The polyolefin microporous film may be a single layer or a multilayer film composed of two or more layers having different molecular weights or average pore diameters. As a method for producing a multilayer film composed of two or more layers, for example, the polyolefin resin constituting the A1 layer or the A2 layer is melt-kneaded with a film-forming solvent, and the resulting molten mixture is sent from each extruder to one die. It is possible to produce either a method in which gel sheets constituting each component are integrated and co-extruded or a method in which gel sheets constituting each layer are superposed and heat-sealed. The coextrusion method is more preferable because it is easy to obtain a high interlayer adhesive strength, and it is easy to form communication holes between layers, so that high permeability is easily maintained and productivity is excellent.
　ポリオレフィン微多孔膜の膜厚は、今後、進むであろう電池の体積エネルギーの高密度化の観点から、３μｍ以上１０μｍ未満が好ましく、より好ましくは５μｍ以上９．０μｍ未満、さらに好ましくは６μｍ以上８μｍ未満である。 The film thickness of the polyolefin microporous membrane is preferably 3 μm or more and less than 10 μm, more preferably 5 μm or more and less than 9.0 μm, and even more preferably 6 μm or more and 8 μm, from the viewpoint of increasing the volume energy of the battery that will be advanced in the future. Is less than.
　ポリオレフィン微多孔膜の平均孔径は、孔閉塞速度と孔閉塞温度の観点から、０．０１～１．０μｍ、好ましくは０．０５～０．５μｍ、さらに好ましくは０．１～０．３μｍである。ポリオレフィン微多孔膜の平均孔径が上記好ましい範囲内であると、多孔層を積層した際に透気抵抗度が大幅に悪化することなく、多孔層の樹脂によるアンカー効果が得られる。 The average pore diameter of the polyolefin microporous membrane is 0.01 to 1.0 μm, preferably 0.05 to 0.5 μm, more preferably 0.1 to 0.3 μm, from the viewpoint of the pore closing speed and the pore closing temperature. . When the average pore diameter of the polyolefin microporous membrane is within the above-mentioned preferable range, the anchoring effect by the resin of the porous layer can be obtained without significantly deteriorating the air resistance when the porous layer is laminated.
　ポリオレフィン微多孔膜の透気抵抗度は５０～５００ｓｅｃ／１００ｃｃＡｉｒが好ましい。ポリオレフィン微多孔膜の空孔率は３０～７０％が好ましい。ポリオレフィン微多孔膜の透気抵抗度及び空孔率が上記好ましい範囲内であると、十分な電池の充放電特性、特にイオン透過性（充放電作動電圧）、電池の寿命（電解液の保持量と密接に関係する）を得ることができる。 The air permeability resistance of the polyolefin microporous membrane is preferably 50 to 500 sec / 100 cc Air. The porosity of the polyolefin microporous membrane is preferably 30 to 70%. When the air permeability resistance and porosity of the polyolefin microporous membrane are within the above-mentioned preferable ranges, sufficient charge / discharge characteristics of the battery, particularly ion permeability (charge / discharge operating voltage), battery life (electrolyte retention amount) Closely related).
２．多孔層
　次に多孔層について説明する。
　多孔層は板状無機粒子と略球状有機粒子を含む。板状無機粒子はその耐熱性によりポリオレフィン微多孔膜を補強し溶融破膜特性を向上させる役割を担う。略球状有機粒子は電極材料との接着性を向上させ、電池に組み込んだときのサイクル特性を向上させる役割を担う。多孔層はポリオレフィン微多孔膜に板状無機粒子を含む塗工液Ａ、略球状有機粒子を含む塗工液Ｂを順次塗布することで形成される。ポリオレフィン微多孔膜に多孔層を設けることで高い安全性を確保でき、さらに長寿命の電池が得られる。 2. Next, the porous layer will be described.
The porous layer includes plate-like inorganic particles and substantially spherical organic particles. The plate-like inorganic particles play a role of reinforcing the polyolefin microporous membrane by its heat resistance and improving the melt-breaking properties. The substantially spherical organic particles play a role of improving the adhesion with the electrode material and improving the cycle characteristics when incorporated in a battery. The porous layer is formed by sequentially applying a coating liquid A containing plate-like inorganic particles and a coating liquid B containing substantially spherical organic particles to a polyolefin microporous film. By providing a porous layer on the polyolefin microporous membrane, high safety can be ensured, and a battery having a longer life can be obtained.
（１）塗工液Ａ
　塗工液Ａは板状無機粒子と分散媒を含み、必要に応じてバインダーを含んでもよい。
　板状無機粒子の材質は特に限定されないが、アルミナ、ベーマイト、雲母が比較的入手しやすく好適である。特に、ベーマイトは硬度が低く、塗工ロールなどの摩耗を抑えられるという観点から好ましい。 (1) Coating liquid A
The coating liquid A contains plate-like inorganic particles and a dispersion medium, and may contain a binder as necessary.
The material of the plate-like inorganic particles is not particularly limited, but alumina, boehmite, and mica are relatively easily available and suitable. In particular, boehmite is preferable from the viewpoint that the hardness is low and wear of a coating roll or the like can be suppressed.
　本明細書でいう板状無機粒子とは、アスペクト比（長径／厚さ）が１．５以上であり、長径／短径の比は１以上、１０以下のものをいう。板状無機粒子のアスペクト比の下限値は２が好ましく、より好ましくは３、さらに好ましくは５である。上限値は５０が好ましく、より好ましくは２０、さらに好ましくは１０である。板状無機粒子の平均粒径（平均長径）は０．５μｍから２．０μｍが好ましく、平均厚さは０．１μｍ以上、０．５μｍ未満が好ましい。板状無機粒子のアスペクト比と平均粒径が上記好ましい範囲内であると、板状無機粒子をポリオレフィン微多孔膜の面方向に対して略平行方向に配置しやすい。略平行方向に配置することによって、多孔層に比較的高密度に充填でき、多孔層に大きさ１μｍを超えるような粗大な空隙や表面突起の発生を抑制できる。 As used herein, the term “plate-like inorganic particles” refers to particles having an aspect ratio (major axis / thickness) of 1.5 or more and a major axis / minor axis ratio of 1 to 10. The lower limit of the aspect ratio of the plate-like inorganic particles is preferably 2, more preferably 3, and still more preferably 5. The upper limit is preferably 50, more preferably 20, and even more preferably 10. The average particle size (average major axis) of the plate-like inorganic particles is preferably 0.5 μm to 2.0 μm, and the average thickness is preferably 0.1 μm or more and less than 0.5 μm. When the aspect ratio and average particle diameter of the plate-like inorganic particles are within the above-mentioned preferable ranges, the plate-like inorganic particles can be easily arranged in a direction substantially parallel to the plane direction of the polyolefin microporous membrane. By disposing in a substantially parallel direction, the porous layer can be filled with a relatively high density, and generation of coarse voids and surface protrusions exceeding 1 μm in size can be suppressed in the porous layer.
　板状無機粒子の平板面の長軸方向長さと短軸方向長さの比（長径／短径）の平均値は３以下が好ましく、より好ましくは２以下、１に近い値であることが望ましい。 The average value of the ratio of the long axis direction length to the short axis direction length (major axis / minor axis) of the plate-like inorganic particles is preferably 3 or less, more preferably 2 or less and a value close to 1. .
　バインダーは、ポリオレフィン微多孔膜と多孔層の接着性を付与し、板状無機粒子同士を接着させるものであれば特に限定されない。作業環境の観点から、水溶性樹脂または水分散性樹脂が好ましい。水溶性樹脂または水分散性樹脂としては、ポリビニルアルコール、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のアクリル系樹脂が挙げられる。特に、ポリビニルアルコール、アクリル系樹脂が好ましい。アクリル系樹脂は市販されているアクリルエマルジョンを用いることができ、例えば、（株）日本触媒製“アクリセット“（登録商標）ＴＦ－３００、昭和電工（株）製“ポリゾール“（登録商標）ＡＰ－４７３５が挙げられる。 The binder is not particularly limited as long as it provides the adhesion between the polyolefin microporous membrane and the porous layer and adheres the plate-like inorganic particles. From the viewpoint of the working environment, a water-soluble resin or a water-dispersible resin is preferable. Examples of the water-soluble resin or water-dispersible resin include acrylic resins such as polyvinyl alcohol, polyacrylic acid, polyacrylamide, and polymethacrylic acid. In particular, polyvinyl alcohol and acrylic resin are preferable. As the acrylic resin, commercially available acrylic emulsions can be used. For example, “Acryset” (registered trademark) TF-300 manufactured by Nippon Shokubai Co., Ltd., “Polysol” (registered trademark) AP manufactured by Showa Denko K.K. -4735.
　塗工液Ａの分散媒は水を主成分とし、塗工性を向上させるためにエチルアルコール、ブチルアルコール等を添加してもよい。さらに必要に応じてバインダー、分散剤、増粘剤を添加してもよい。 The dispersion medium of the coating liquid A contains water as a main component, and ethyl alcohol, butyl alcohol, or the like may be added to improve the coating property. Furthermore, you may add a binder, a dispersing agent, and a thickener as needed.
　塗工液Ａの粘度は１０～３０ｍＰａ・ｓが好ましく、より好ましくは１２～２５ｍＰａ・ｓ、さらに好ましくは１５～２５ｍＰａ・ｓである。塗工液Ａの板状無機粒子の含有量は４０～６０質量％が好ましい。塗工液Ａの粘度及び板状無機粒子の含有量が上記好ましい範囲内であると、板状無機粒子をポリオレフィン微多孔膜の面方向に対して略平行方向にしやすくなる。 The viscosity of the coating liquid A is preferably 10 to 30 mPa · s, more preferably 12 to 25 mPa · s, and still more preferably 15 to 25 mPa · s. The content of the plate-like inorganic particles in the coating liquid A is preferably 40 to 60% by mass. When the viscosity of the coating liquid A and the content of the plate-like inorganic particles are within the above preferable ranges, the plate-like inorganic particles can be made substantially parallel to the plane direction of the polyolefin microporous membrane.
　塗工量は、破膜強度や電極体として捲回体にした時に体積エネルギー密度を考慮すると１ｇ／ｍ２以上、３ｇ／ｍ２以下が好ましい。 The coating amount is preferably 1 g / m 2 or more and 3 g / m 2 or less in consideration of the volume energy density when the wound body is used as a film breaking strength or an electrode body.
（２）塗工液Ｂ
　塗工液Ｂは略球状有機粒子と分散媒を含み、必要に応じてバインダーを含んでもよい。
略球状有機粒子の円形度は０．９７以上、好ましくは０．９８以上、最も好ましくは０．９９～１．００である。上記略球状有機粒子の円形度とは、例えば、粒子の投影像（粒子画像）から周囲長と面積を算出し、次の式により求めることができる。
円形度＝Ｌ０／Ｌ１ 
ここで、上記式中のＬ０は実際に測定した対象の粒子の投影像（粒子画像）から算出された面積と同一の面積を有する理想円（真円）の周囲長であり、Ｌ１は当該測定対象の粒子の粒子投影像（粒子画像）から測定した実際の周囲長である。 (2) Coating liquid B
The coating liquid B contains substantially spherical organic particles and a dispersion medium, and may contain a binder as necessary.
The circularity of the substantially spherical organic particles is 0.97 or more, preferably 0.98 or more, and most preferably 0.99 to 1.00. The circularity of the substantially spherical organic particles can be obtained, for example, by calculating the perimeter length and area from the projected image (particle image) of the particles and by the following equation.
Circularity = L0 / L1
Here, L0 in the above equation is the perimeter of an ideal circle (perfect circle) having the same area as the area calculated from the projection image (particle image) of the target particle actually measured, and L1 is the measurement. This is the actual perimeter measured from the particle projection image (particle image) of the target particle.
　略球状有機粒子の平均粒径（ｒ）は、下限値が０．１μｍであることが好ましく、より好ましくは０．２μｍであり、さらに好ましくは０．３μｍである。上限値は０．８μｍであることが好ましく、より好ましくは０．７μｍであり、さらに好ましくは０．６μｍである。平均粒径（ｒ）が０．１μｍ未満であると板状無機粒子間の隙間に奥まで入り込み、電極材料との接着性向上に十分寄与しない場合がある。０．８μｍを超えると脱落しやすくなり好ましくない。 The lower limit of the average particle diameter (r) of the substantially spherical organic particles is preferably 0.1 μm, more preferably 0.2 μm, and still more preferably 0.3 μm. The upper limit is preferably 0.8 μm, more preferably 0.7 μm, and even more preferably 0.6 μm. If the average particle size (r) is less than 0.1 μm, it may penetrate into the gaps between the plate-like inorganic particles as far as possible, and may not sufficiently contribute to the improvement in adhesion to the electrode material. If it exceeds 0.8 μm, it tends to fall off, which is not preferable.
　略球状有機粒子は、フッ素系樹脂、アクリル系樹脂または両方を含むことが好ましい。フッ素系樹脂は、フッ化ビニリデン単独重合体、フッ化ビニリデン／フッ化オレフィン共重合体、フッ化ビニル単独重合体、及びフッ化ビニル／フッ化オレフィン共重合体からなる群より選ばれる１種以上を使用することができる。特に、電極材料との接着性の観点からフッ化ビニリデン／ヘキサフルオロプロピレン共重合体が好ましい。この共重合体はヘキサフルオロプロピレンのモル％が１～３モル％であることがより好ましい。この重合体は優れた電極材料との接着性を有し、非水電解液に対して適度な膨潤性を有し、非水電解液に対する化学的、物理的な安定性が高いため、高温下での使用にも電解液との親和性を十分維持できる。 The substantially spherical organic particles preferably contain a fluorine resin, an acrylic resin, or both. The fluororesin is at least one selected from the group consisting of vinylidene fluoride homopolymers, vinylidene fluoride / fluorinated olefin copolymers, vinyl fluoride homopolymers, and vinyl fluoride / fluorinated olefin copolymers. Can be used. In particular, a vinylidene fluoride / hexafluoropropylene copolymer is preferable from the viewpoint of adhesion to an electrode material. In this copolymer, the mol% of hexafluoropropylene is more preferably 1 to 3 mol%. This polymer has excellent adhesion to electrode materials, moderate swelling with non-aqueous electrolytes, and high chemical and physical stability against non-aqueous electrolytes. Affinity with the electrolytic solution can be sufficiently maintained even when used in
　フッ素系樹脂は、市販のフッ素系樹脂を必要により球状に微細化加工して用いることができる。市販のフッ素系樹脂とは例えば、ＡＲＫＥＭＡ社製ＫＹＮＡＲ　ＦＲＥＸ（登録商標）２８５１－００、２８０１－００、２８２１－００、２５０１－２０等が挙げられる。 As the fluororesin, a commercially available fluororesin can be used after being refined into a spherical shape if necessary. Examples of commercially available fluororesins include KYNAR FREX (registered trademark) 2851-00, 2801-00, 2821-00, 2501-20 and the like manufactured by ARKEMA.
　アクリル系樹脂は、電極材料との接着性を有するものであれば特に限定されないが、好ましくはアクリレートモノマーを重合してなる樹脂が好ましい。アクリレートモノマーは、例えば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ－プ口ピル（メタ）アクリレート、イソプ口ピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、tーブチル(メタ)アクリレート、ペンチル（メタ）アクリレート、ヘキシル（メタ
）アクリレート、ヘプチル(メタ)アクリレート、オクチル（メタ）アクリレート、２－エチルヘキシル(メタ)アクリレート、ノニル(メタ)アクリレート、デシル(メタ)アクリレート、ラウリル(メタ)アクリレート、ｎ－テトラデシル（メタ）アクリレート、ステアリル（メタ）アクリレートなどのアルキル（メタ）アクリレート、ヒド口キシエチル(メタ)アクリレート、ヒド口キシプ口ピル（メタ）アクリレート、ヒド口キシブチル(メタ)アクリレート等のヒド口キシ基含有（メタ）アクリレートが挙げられる。また、市販のアクリル系樹脂粒子を分散させた塗工液を用いてもよい。市販のアクリル系樹脂粒子を分散させた塗工液とは例えば、ＪＳＲ株式会社製アクリルラテックス商品名：ＴＲＤ２０２Ａなどが挙げられる。架橋していない有機粒子が電極材料との接着性の観点から好ましい。 The acrylic resin is not particularly limited as long as it has adhesiveness with the electrode material, but a resin obtained by polymerizing an acrylate monomer is preferable. Examples of the acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl meth (acrylate), isopyl pill (meth) acrylate, n-butyl (meth) acrylate, and t-butyl (meth) acrylate. , Pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate , N-tetradecyl (meth) acrylate, alkyl (meth) acrylate such as stearyl (meth) acrylate, hydroxoxyethyl (meth) acrylate, hydroxipyl pill (meth) acrylate, hydroxoxybutyl (meth) acrylate, etc. De port carboxymethyl group-containing (meth) acrylate. Also, a coating liquid in which commercially available acrylic resin particles are dispersed may be used. Examples of the coating liquid in which commercially available acrylic resin particles are dispersed include ASR latex product name: TRD202A manufactured by JSR Corporation. Non-crosslinked organic particles are preferred from the viewpoint of adhesion to the electrode material.
　塗工液Ｂの分散媒は水を主成分とし、塗工性を向上させるために必要に応じてエチルアルコール、ブチルアルコール等を添加してもよい。さらに必要に応じて、バインダー、分散剤、増粘剤を添加してもよい。 The dispersion medium of the coating liquid B contains water as a main component, and ethyl alcohol, butyl alcohol, or the like may be added as necessary in order to improve coating properties. Furthermore, you may add a binder, a dispersing agent, and a thickener as needed.
　バインダーは、ポリオレフィン微多孔膜と多孔層の接着性を付与し、略球状有機粒子同士を接着させるものであれば特に限定されない。例えば、第一の層と同じバインダーを用いることができる。 The binder is not particularly limited as long as it imparts adhesion between the polyolefin microporous membrane and the porous layer and adheres substantially spherical organic particles. For example, the same binder as the first layer can be used.
　塗工液Ｂの粘度は、１～１０ｍＰａ・ｓが好ましく、より好ましくは２～８ｍＰａ・ｓ、さらに好ましくは３～６ｍＰａ・ｓである。塗工液Ｂの略球状有機粒子の含有量は、３～１０質量％が好ましい。塗工液Ｂの略球状有機粒子の粘度及び含有量が上記好ましい範囲内であると、略球状有機粒子が板状無機粒子の上を転がり、板状無機粒子間の表面凹部入り込みやすくなり、図１及び２に示すような、略球状有機粒子の集合体と板状無機粒子の海島構造状態を得やすくなる。 The viscosity of the coating liquid B is preferably 1 to 10 mPa · s, more preferably 2 to 8 mPa · s, and further preferably 3 to 6 mPa · s. The content of the substantially spherical organic particles in the coating liquid B is preferably 3 to 10% by mass. When the viscosity and content of the substantially spherical organic particles of the coating liquid B are within the above preferred range, the substantially spherical organic particles roll on the plate-like inorganic particles, and the surface recesses between the plate-like inorganic particles are likely to enter. As shown in 1 and 2, it becomes easy to obtain a sea-island structure state of aggregates of substantially spherical organic particles and plate-like inorganic particles.
　略球状有機粒子の体積は、略球状有機粒子と板状無機粒子の総体積に対して１０～３０体積％であることが好ましい。１０体積％以上であればと電極材料との接着性を付与または向上させる機能が得られやすい。３０体積％以下であれば相対的に板状無機粒子の含有量を多く保つことができ、十分な破膜強度を得られやすい。 The volume of the substantially spherical organic particles is preferably 10 to 30% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. If it is 10 volume% or more, the function which provides or improves the adhesiveness with an electrode material will be easy to be obtained. If it is 30% by volume or less, a relatively large content of the plate-like inorganic particles can be maintained, and sufficient film breaking strength can be easily obtained.
　略球状有機粒子の平均粒径ｒ（μｍ）と板状無機粒子の平均厚さｔ（μｍ）の比（ｒ／ｔ）を０．３≦ｒ／ｔ≦１．０の範囲内にすることが重要である。上記好ましい範囲内であると、板状無機粒子層に塗工液Ｂを塗布する際に略球状有機粒子が板状無機粒子層の表面を転がり、板状無機粒子層の凹部に入り込みやすくなる。この結果、多孔層の断面は略球状有機粒子が電極との接着性を有するように板状無機粒子層の表面の凹部に入り込んだ形態を有する（図１参照）。多孔層の表面を拡大観察すると、略球状有機粒子が板状無機粒子層の表面の凹部を埋めるように存在することで板状無機粒子と球状有機粒子の集合体が認められ、海島構造様の形態を有する（図２参照）。なお、図２は板状無機粒子が島、球状有機粒子の集合体が海の例である。ここで全ての略球状有機粒子が凹部に入り込む必要はない。多孔層が海島構造の形態となることで、多孔層の厚さが増加するのを抑制しながら、電極材料との接着性向上が図れる。強いては得られる電池の体積エネルギー密度の向上に繋がる。 The ratio (r / t) of the average particle diameter r (μm) of the substantially spherical organic particles to the average thickness t (μm) of the plate-like inorganic particles is set within the range of 0.3 ≦ r / t ≦ 1.0. is important. Within the above preferable range, when the coating liquid B is applied to the plate-like inorganic particle layer, the substantially spherical organic particles roll on the surface of the plate-like inorganic particle layer and easily enter the recesses of the plate-like inorganic particle layer. As a result, the cross section of the porous layer has a form in which the substantially spherical organic particles enter the recesses on the surface of the plate-like inorganic particle layer so as to have adhesiveness with the electrode (see FIG. 1). When the surface of the porous layer is magnified, almost spherical organic particles are present so as to fill the recesses on the surface of the plate-like inorganic particle layer, and an aggregate of plate-like inorganic particles and spherical organic particles is observed. It has a form (see FIG. 2). FIG. 2 shows an example in which the plate-like inorganic particles are islands and the aggregate of spherical organic particles is the sea. Here, it is not necessary for all the substantially spherical organic particles to enter the recess. Since the porous layer has a sea-island structure, the adhesion with the electrode material can be improved while suppressing an increase in the thickness of the porous layer. If it is strong, it leads to the improvement of the volume energy density of the battery obtained.
　多孔層の膜厚は得られた電池の使用目的によっても異なるが、０．５～２．５μｍが好ましく、より好ましくは０．８～２．２μｍ、さらに好ましくは１．０～２．０μｍである。多孔層の膜厚が上記好ましい範囲内であると、電極材料との接着性を付与または向上させることができる。また、ポリオレフィン微多孔膜がポリオレフィンの融点以上で溶融・収縮した際の破膜強度を維持し、絶縁性を確保できる。さらに、電極体として捲回体にした時に高い体積エネルギー密度が得られる。 The thickness of the porous layer varies depending on the intended use of the obtained battery, but is preferably 0.5 to 2.5 μm, more preferably 0.8 to 2.2 μm, and still more preferably 1.0 to 2.0 μm. is there. Adhesiveness with an electrode material can be provided or improved as the film thickness of the porous layer is within the above preferred range. In addition, the membrane breaking strength when the polyolefin microporous membrane is melted / shrinked at a temperature equal to or higher than the melting point of the polyolefin can be maintained, and insulation can be secured. Further, a high volume energy density can be obtained when a wound body is used as the electrode body.
　多孔層の空孔率は、膜の電気抵抗と膜強度の観点から３０～９０％が好ましい。 The porosity of the porous layer is preferably 30 to 90% from the viewpoint of the electric resistance and film strength of the film.
　多孔層の透気抵抗度は、膜強度とサイクル特性の観点から、ＪＩＳ　Ｐ　８１１７に準拠した方法により測定した値が１～６００ｓｅｃ／１００ｃｃＡｉｒであることが好ましい。 The air resistance of the porous layer is preferably 1 to 600 sec / 100 cc Air measured by a method based on JIS P 8117 from the viewpoint of film strength and cycle characteristics.
３．電池用セパレータ
　電池用セパレータについて説明する。
　本発明の電池用セパレータは、板状無機粒子を含む塗工液Ａと略球状有機粒子を含む塗工液Ｂをポリオレフィン微多孔膜に塗布することで得られる。例えば、板状無機粒子をポリオレフィン微多孔膜に対して略平行方向となるように塗工液Ａをポリオレフィン微多孔膜に塗工し、乾燥して板状無機粒子層を形成し、その後、板状無機粒子層上に塗工液Ｂを塗工、乾燥して、ポリオレフィン微多孔膜に多孔層を設けることで得られる。つまり、２段階の塗工工程を得て多孔層を積層するのが好ましい。これにより、略球状有機粒子を板状無機粒子層の表面に偏在させ薄くて十分な電極材料との接着性を得ることができる。あらかじめ板状無機粒子と略球状有機粒子を混合した塗工液を用いると、略球状有機粒子を多孔層の表層に偏在させることが困難となる。また、十分な電極材料との接着性を得ようとすれば多孔層を厚くする必要がある。さらに、板状無機粒子の方向が不規則となり、多孔層内に大きさ１μｍを超えるような空隙ができやすく、略平行になっていない板状無機粒子が表面に突起として発生しやすくなり電極体として捲回した際、空隙が発生しやすくなる。 3. Battery Separator A battery separator will be described.
The battery separator of the present invention is obtained by applying a coating liquid A containing plate-like inorganic particles and a coating liquid B containing substantially spherical organic particles to a polyolefin microporous film. For example, the coating liquid A is applied to the polyolefin microporous membrane so that the plate-like inorganic particles are substantially parallel to the polyolefin microporous membrane, and dried to form a plate-like inorganic particle layer. It is obtained by coating the coating liquid B on the fibrous inorganic particle layer and drying it to provide a porous layer on the polyolefin microporous membrane. That is, it is preferable to obtain a two-step coating process and laminate the porous layer. Thereby, substantially spherical organic particles are unevenly distributed on the surface of the plate-like inorganic particle layer, and a thin and sufficient adhesive property with the electrode material can be obtained. When a coating liquid in which plate-like inorganic particles and substantially spherical organic particles are mixed in advance is used, it becomes difficult to make the substantially spherical organic particles unevenly distributed on the surface layer of the porous layer. Moreover, if it is going to acquire adhesiveness with sufficient electrode material, it is necessary to make a porous layer thick. Further, the direction of the plate-like inorganic particles becomes irregular, and voids exceeding 1 μm in size are easily formed in the porous layer, and plate-like inorganic particles that are not substantially parallel are easily generated as protrusions on the surface, and the electrode body. As a result, voids are likely to occur.
　塗工液Ｂは板状無機粒子層上にのみ塗布してもよいし、さらに板状無機粒子層が設けられていないポリオレフィン微多孔膜のもう一方の面に塗布してもよい。電極材料との接着性を得るため塗工液Ｂの略球状有機粒子が表面に偏在するように塗布できればよい。 The coating liquid B may be applied only on the plate-like inorganic particle layer, or may be applied to the other surface of the polyolefin microporous film not provided with the plate-like inorganic particle layer. In order to obtain adhesiveness with the electrode material, it is sufficient that the substantially spherical organic particles of the coating liquid B can be applied so as to be unevenly distributed on the surface.
　湿式塗工方法は公知の方法を採用することができる。例えば、ロールコート法、グラビアコート法、キスコート法、ディップコート法、スプレーコート法、エアナイフコート法、マイヤーバーコート法、パイプドクター法、ブレードコート法およびダイコート法などが挙げられる。特に、ポリオレフィン微多孔膜上で塗工液に比較的強い剪断力を加えながら塗工する方法が好ましく、ロールコート法、グラビアコート法の内、リバースロールコート法、リバースグラビアコート法が好ましい。これらの塗工方法はポリオレフィン微多孔膜の走行方向と対する塗工ロールの回転方向が逆であるため、塗工液に強い剪断力を与えることができ、板状無機粒子がポリオレフィン微多孔膜に対して略平行になるようにできる。 A well-known method can be adopted as the wet coating method. Examples thereof include a roll coating method, a gravure coating method, a kiss coating method, a dip coating method, a spray coating method, an air knife coating method, a Meyer bar coating method, a pipe doctor method, a blade coating method, and a die coating method. In particular, a method of applying a relatively strong shearing force to the coating solution on the polyolefin microporous film is preferable, and among the roll coating method and the gravure coating method, the reverse roll coating method and the reverse gravure coating method are preferable. In these coating methods, the rotation direction of the coating roll relative to the traveling direction of the polyolefin microporous membrane is opposite, so that a strong shearing force can be applied to the coating liquid, and the plate-like inorganic particles are applied to the polyolefin microporous membrane. It can be made to be substantially parallel to it.
　ポリオレフィン微多孔膜の搬送速度（Ｆ）と逆回転する塗工ロールの周速（Ｓ）との比（以下、Ｓ／Ｆ比と略記する。）は、１．０２以上が好ましい。より好ましい下限値は１．０５、さらに好ましくは１．０７である。１．０２以上であれば塗工液に十分な剪断力を掛けることができる。上限は特に定めないが１．２０とすることができる。 The ratio between the conveying speed (F) of the polyolefin microporous membrane and the peripheral speed (S) of the coating roll rotating in reverse (hereinafter abbreviated as S / F ratio) is preferably 1.02 or more. A more preferred lower limit is 1.05, and even more preferably 1.07. If it is 1.02 or more, a sufficient shearing force can be applied to the coating solution. The upper limit is not particularly defined but can be 1.20.
　電池用セパレータの全体の膜厚は、機械強度と絶縁性の観点から、６～１３μｍが好ましく、より好ましくは７～１２μｍである。また、電極体として捲回体にした時に高い体積エネルギー密度が得られことができる。 The total thickness of the battery separator is preferably 6 to 13 μm, more preferably 7 to 12 μm, from the viewpoint of mechanical strength and insulation. Also, a high volume energy density can be obtained when a wound body is used as the electrode body.
　以下実施例を示して具体的に説明するが、本発明はこれらの実施例よって何ら制限されるものではない。なお、実施例中の測定値は以下の方法で測定した値である。 Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. In addition, the measured value in an Example is a value measured with the following method.
１．高密度捲回性の評価
　実施例、比較例で得られた電池用セパレータを外形９６ｍｍ、肉厚１０ｍｍの紙管に５０Ｎ／ｍの張力でセパレータの肉厚が１５ｍｍになるまで巻き付け、その巻き長さを計測した。セパレータの肉厚は巻き取り前の任意の紙管表面位置を０ｍｍとし、レーザーセンサーによって検知した。比較例１の巻き長さを１００とし、各実施例、比較例のセパレータ巻き長さを相対的に比較した。値が大きいほど高密度捲回性が優れることを意味する。 1. Evaluation of high density winding property The battery separators obtained in Examples and Comparative Examples were wound around a paper tube having an outer diameter of 96 mm and a thickness of 10 mm until the separator thickness reached 15 mm with a tension of 50 N / m, and the winding length. Measured. The thickness of the separator was detected by a laser sensor with an arbitrary paper tube surface position before winding of 0 mm. The winding length of Comparative Example 1 was set to 100, and the separator winding lengths of Examples and Comparative Examples were relatively compared. Higher values mean higher density winding properties.
２．略球状有機粒子の平均粒径の測定
（１）分散媒に分散されている場合
　試料を適当な濃度（固形分濃度２～３質量％）に希釈し、該希釈液をスライドガラス上に滴下し、光学顕微鏡で観察した。光学顕微鏡観察で得られた画像上で任意の２０個を選択し、それら２０個の粒径の平均値を略球状有機粒子の平均粒径とした。
（２）粉末の場合
　測定用セルに上に両面テープを貼り、該両面テープ上全面に略球状有機粒子を固着させた。次いで、プラチナまたは金を数分間真空蒸着させ、ＳＥＭ観察用試料を得た。得られた試料を倍率２０，０００倍でＳＥＭ観察をおこなった。ＳＥＭ測定で得られた画像上で任意の２０個を選択し、それら２０個の粒径の平均値を略球状有機粒子の平均粒径とした。 2. Measurement of average particle size of approximately spherical organic particles (1) When dispersed in a dispersion medium Sample is diluted to an appropriate concentration (solid content concentration of 2 to 3% by mass), and the diluted solution is dropped on a slide glass. And observed with an optical microscope. Arbitrary 20 particles were selected on the image obtained by observation with an optical microscope, and the average value of the particle sizes of the 20 particles was defined as the average particle size of the substantially spherical organic particles.
(2) In the case of powder A double-sided tape was stuck on the measurement cell, and substantially spherical organic particles were fixed on the entire surface of the double-sided tape. Next, platinum or gold was vacuum deposited for several minutes to obtain a sample for SEM observation. The obtained sample was observed by SEM at a magnification of 20,000 times. Arbitrary 20 particles were selected on the image obtained by SEM measurement, and the average value of the particle diameters of the 20 particles was defined as the average particle diameter of the substantially spherical organic particles.
３．板状無機粒子の平均厚さの測定
　測定用セルに上に両面テープを貼り、該両面テープ上全面に板状無機粒子を固着させた。次いで、プラチナまたは金を数分間真空蒸着させＳＥＭ観察用試料を得た。得られた試料を倍率２０，０００倍でＳＥＭ観察をおこなった。ＳＥＭ測定で得られた画像上で両面テープに対し、垂直に立っている任意の２０個を選択し、それら２０個の板状無機粒子の厚さの平均値を板状無機粒子の平均厚さとした。 3. Measurement of average thickness of plate-like inorganic particles A double-sided tape was stuck on the measurement cell, and the plate-like inorganic particles were fixed on the entire surface of the double-sided tape. Subsequently, platinum or gold was vacuum-deposited for several minutes to obtain a sample for SEM observation. The obtained sample was observed by SEM at a magnification of 20,000 times. On the image obtained by SEM measurement, arbitrary 20 standing vertically with respect to the double-sided tape are selected, and the average thickness of the 20 plate-like inorganic particles is defined as the average thickness of the plate-like inorganic particles. did.
４．板状無機粒子の平均粒径
　上記３で用いたＳＥＭ測定で得られた画像上の中から、両面テープに対し画像上で平面形状が観察される任意の２０個を選択し、それら２０個の長径の長さの平均値を板状無機粒子の平均粒径とした。 4). Average particle size of the plate-like inorganic particles From among the images obtained by the SEM measurement used in the above 3, arbitrary 20 particles whose planar shape is observed on the image are selected with respect to the double-sided tape. The average value of the length of the major axis was taken as the average particle size of the plate-like inorganic particles.
５．膜厚
　接触式膜厚計（ソニーマニュファクチュアリングシステムズ（株）製 デジタルマイクロメーター Ｍ－３０）を使用して測定した。 5). Film thickness Measured using a contact-type film thickness meter (Digital Micrometer M-30 manufactured by Sony Manufacturing Systems Co., Ltd.).
６．電極材料との接着性
　負極および電池用セパレータをそれぞれ２ｃｍ×５ｃｍの大きさに切り出し、負極の活物質面と電池用セパレータの改質多孔層面を合わせ、１ＭのＬｉＰＦ６濃度の１：２の重量組成を有するＥＣ（Ethylene Carbonate）／ＥＭＣ（Ethyl Methyl Carbonate）を含んでなる液体電解質に浸した。貼り合わせ面の温度を５０℃に保持しながら２ＭＰａの圧力で３分間プレスした。その後、負極と電池用セパレータを剥がし、電池用セパレータの剥離面を観察して以下の基準より判定した。なお、負極電極としてパイオトレック社製、層コート電極Ａ１００（１．６ｍＡｈ／ｃｍ２）を用いた。
◎：負極の活物質が電池用セパレータの改質多孔層に面積比で８０％以上付着
○：負極の活物質が電池用セパレータの改質多孔層に面積比で５０％以上、８０％未満付着
△：負極の活物質が電池用セパレータの改質多孔層に面積比で３０％以上、５０％未満付着
×：負極の活物質が電池用セパレータの改質多孔層に面積比で３０％未満付着 6). Adhesiveness with electrode material Each of the negative electrode and battery separator was cut into a size of 2 cm × 5 cm, the active material surface of the negative electrode and the modified porous layer surface of the battery separator were combined, and the weight of 1: 2 of 1M LiPF 6 concentration It was immersed in a liquid electrolyte comprising EC (Ethylene Carbonate) / EMC (Ethyl Methyl Carbonate) having the composition. While maintaining the temperature of the bonded surface at 50 ° C., pressing was performed at a pressure of 2 MPa for 3 minutes. Thereafter, the negative electrode and the battery separator were peeled off, and the peeled surface of the battery separator was observed to make a judgment based on the following criteria. In addition, the layer coat electrode A100 (1.6mAh / cm < 2 >) by the Piotrec company company was used as a negative electrode.
A: Active material of the negative electrode adheres to the modified porous layer of the battery separator in an area ratio of 80% or more. O: Active material of the negative electrode adheres to the modified porous layer of the battery separator in an area ratio of 50% or more and less than 80%. Δ: Active material of negative electrode adheres to modified porous layer of battery separator in area ratio of 30% or more and less than 50% ×: Active material of negative electrode adheres to modified porous layer of battery separator in an area ratio of less than 30%
７．溶融破膜特性（メルトダウン特性）
　実施例及び比較例で得られたセパレータを５℃／分の昇温速度で加熱しながら、王研式透気抵抗度計（旭精工株式会社製、ＥＧＯ-１Ｔ）により透気抵抗度を測定し、透気抵抗度が検出限界である１×１０５ｓｅｃ／１００ｃｃに到達した後、再び１×１０５ｓｅｃ／１００ｃｃ以下に降下し始めた温度を求め、メルトダウン温度（℃）とした。
判定
メルトダウン温度（℃）が２００℃を超える場合・・・○
メルトダウン温度（℃）が２００℃以下の場合・・・・× 7). Melt film breaking characteristics (meltdown characteristics)
While the separators obtained in the examples and comparative examples were heated at a rate of temperature increase of 5 ° C./min, the air resistance was measured with an Oken type air resistance meter (Asahi Seiko Co., Ltd., EGO-1T). Then, after the air resistance reached the detection limit of 1 × 10 5 sec / 100 cc, the temperature at which the air resistance began to drop again to 1 × 10 5 sec / 100 cc or less was obtained and was defined as the meltdown temperature (° C.).
When the judgment meltdown temperature (° C) exceeds 200 ° C
When the meltdown temperature (° C) is 200 ° C or lower ··· ×
８．塗工液の粘度
　粘度計(BROOKFIELD社製DV-I PRIME)を用い、２５℃での塗工液の粘度を測定した。 8). Viscosity of coating liquid The viscosity of the coating liquid at 25 ° C. was measured using a viscometer (DV-I PRIME manufactured by BROOKFIELD).
実施例１
（塗工液Ａの調製）
　イオン交換水５８質量部とブタノール１質量部からなる混合液に（平均粒径１．０μｍ、平均厚さ０．４μｍの板状ベーマイト、長径／短径比２）を４０質量部、バインダーとしてケン化度９５％のポリビニルアルコール１質量部を添加しよく分散させた。次いで、増粘剤としてカルボキシメチルセルロース（ＣＭＣ）添加し、液粘度を２０ｍＰａ・ｓに調整して塗工液Ａ１とした。
（塗工液Ｂの調製）
　イオン交換水７９質量部とブタノール１質量部からなる混合液にアクリル系樹脂からなる略球状有機粒子分散液（ＪＳＲ株式会社製ＴＲＤ２０２Ａ、平均粒径０．２μｍ、固形分濃度４０質量％）を２０質量部添加し、攪拌して均一に分散させた。次いで、カルボキシメチルセルロース（ＣＭＣ）添加し、液粘度を５ｍＰａ・ｓに調整して塗工液Ｂ１とした。
（多孔層の積層）
　ポリエチレン微多孔膜（厚さ７μｍ、空孔率２１％、透気抵抗度１２０秒／１００ｃｃ）の片面にリバースグラビアコート法を用いて搬送速度３０ｍ／分、Ｓ／Ｆ比１．０５の条件で塗工液Ａ１を塗布、乾燥し、板状無機粒子層を積層した。板状無機粒子層の乾燥時の目付は２．５ｇ／ｍ２であった。次いで、板状無機粒子層上に塗工液Ｂ１を塗工液Ａ１と同様にして塗布、乾燥して電池用セパレータを得た。なお、塗工目付は略球状有機粒子と板状無機粒子の総体積に対して、略球状有機粒子の体積が１５体積％となるようにした。 Example 1
(Preparation of coating solution A)
40 parts by weight of a mixture of 58 parts by weight of ion-exchanged water and 1 part by weight of butanol (plate boehmite having an average particle diameter of 1.0 μm and an average thickness of 0.4 μm, major axis / minor axis ratio of 2) and Ken as a binder 1 part by mass of 95% of polyvinyl alcohol was added and dispersed well. Subsequently, carboxymethylcellulose (CMC) was added as a thickener, and the liquid viscosity was adjusted to 20 mPa · s to obtain a coating liquid A1.
(Preparation of coating solution B)
A mixture of 79 parts by mass of ion-exchanged water and 1 part by mass of butanol was charged with a substantially spherical organic particle dispersion liquid (TRD202A manufactured by JSR Corporation, average particle size 0.2 μm, solid content concentration 40% by mass) made of acrylic resin. Part by mass was added and stirred to disperse uniformly. Subsequently, carboxymethylcellulose (CMC) was added, and the liquid viscosity was adjusted to 5 mPa · s to obtain a coating liquid B1.
(Lamination of porous layer)
Using a reverse gravure coating method on one side of a polyethylene microporous membrane (thickness 7 μm, porosity 21%, air permeability 120 sec / 100 cc) under conditions of a conveyance speed of 30 m / min and an S / F ratio of 1.05 The coating liquid A1 was applied and dried, and a plate-like inorganic particle layer was laminated. The basis weight when the plate-like inorganic particle layer was dried was 2.5 g / m 2 . Next, the coating liquid B1 was applied onto the plate-like inorganic particle layer in the same manner as the coating liquid A1 and dried to obtain a battery separator. The coating weight was such that the volume of the substantially spherical organic particles was 15% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles.
実施例２
　板状ベーマイトに替えて板状ベーマイト粒子（平均粒径２．０μｍ、平均厚さ０．４μｍ、長径／短径比３）とした塗工液Ａ２を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 2
The same procedure as in Example 1 was conducted except that coating liquid A2 in the form of plate-like boehmite particles (average particle size 2.0 μm, average thickness 0.4 μm, major axis / minor axis ratio 3) was used instead of plate-like boehmite. A battery separator was obtained.
実施例３
　液粘度を１０ｍＰａ・ｓに調整した塗工液Ａ３を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 3
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A3 having a liquid viscosity adjusted to 10 mPa · s was used.
実施例４
　液粘度を３０ｍＰａ・ｓに調整した塗工液Ａ４を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 4
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A4 having a liquid viscosity adjusted to 30 mPa · s was used.
実施例５
　板状ベーマイト粒子の平均粒径１．０μｍ、平均厚さを０．２μｍ、長径／短径比３とした塗工液Ａ５を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 5
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A5 having an average particle size of 1.0 μm, an average thickness of 0.2 μm, and a major axis / minor axis ratio of 3 was used. .
実施例６
　板状ベーマイト粒子を平均粒径２．０μｍ、平均厚さ０．６μｍ、長径／短径比３とした塗工液Ａ６を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 6
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A6 having an average particle size of 2.0 μm, an average thickness of 0.6 μm, and a major axis / minor axis ratio of 3 was used for the plate-like boehmite particles.
実施例７
　塗工液Ｂの塗工量を調整し、略球状有機粒子と板状無機粒子の総体積に対して略球状有機粒子の体積が２５体積％となるようにした以外は実施例１と同様にして電池用セパレータを得た。 Example 7
The same procedure as in Example 1 was performed except that the coating amount of the coating liquid B was adjusted so that the volume of the substantially spherical organic particles was 25% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. Thus, a battery separator was obtained.
実施例８
　塗工液Ａを塗布する際にＳ／Ｆ比１．１８の条件とした以外は実施例１と同様にして電池用セパレータを得た。 Example 8
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A was applied under conditions of an S / F ratio of 1.18.
実施例９
　塗工液Ｂの調製において、液粘度を１０ｍＰａ・ｓに調整した塗工液Ｂ２を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 9
In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B2 having a liquid viscosity adjusted to 10 mPa · s was used.
実施例１０
　塗工液Ｂの調製において、液粘度を２ｍＰａ・ｓに調整した塗工液Ｂ３を用いた以外は実施例１と同様にして電池用セパレータを得た。 Example 10
In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B3 having a liquid viscosity adjusted to 2 mPa · s was used.
比較例１
（塗工液の調製）
　イオン交換水５８質量部とブタノール１質量部からなる混合液に平均粒径１．０μｍ、平均厚さ０．４μｍの板状ベーマイトを４０質量部、バインダーとしてケン化度９５％のポリビニルアルコール１質量部、及び平均粒径０．２μｍのアクリル系樹脂からなる略球状有機粒子分散液（ＪＳＲ株式会社製ＴＲＤ２０２Ａ、固形分濃度４０質量％）を略球状有機粒子と板状無機粒子の総体積に対して略球状有機粒子の体積が１５体積％となるように添加し、よく分散させた。この分散液に増粘剤としてカルボキシメチルセルロース（ＣＭＣ）添加し、液粘度を２０ｍＰａ・ｓに調整して塗工液Ｃとした。
（多孔層の積層）
　ポリエチレン微多孔膜（厚さ７μｍ、空孔率２１％、透気抵抗度１２０秒／１００ｃｃ）に図３に示す塗工装置（リバースグラビアコート法）を用いて搬送速度３０ｍ／分、Ｓ／Ｆ比１．０５の条件で塗布、乾燥し、多孔層を積層し、電池用セパレータを得た。多孔層の乾燥時の目付は２．７ｇ／ｍ２であった。 Comparative Example 1
(Preparation of coating solution)
40 parts by mass of plate boehmite having an average particle diameter of 1.0 μm and an average thickness of 0.4 μm in a mixed solution composed of 58 parts by mass of ion-exchanged water and 1 part by mass of butanol, and 1 mass of polyvinyl alcohol having a saponification degree of 95% as a binder And a substantially spherical organic particle dispersion liquid (TRD202A manufactured by JSR Corporation, solid content concentration 40% by mass) made of an acrylic resin having an average particle size of 0.2 μm with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles Then, it was added so that the volume of the substantially spherical organic particles was 15% by volume and well dispersed. Carboxymethylcellulose (CMC) was added as a thickener to this dispersion, and the liquid viscosity was adjusted to 20 mPa · s to obtain a coating liquid C.
(Lamination of porous layer)
Using a coating device (reverse gravure coating method) shown in FIG. 3 on a polyethylene microporous membrane (thickness 7 μm, porosity 21%, air permeability 120 seconds / 100 cc), a conveyance speed of 30 m / min, S / F Coating and drying were performed under the condition of a ratio of 1.05, and a porous layer was laminated to obtain a battery separator. The basis weight when the porous layer was dried was 2.7 g / m 2 .
比較例２
　塗工液Ａの調製において、板状ベーマイトに替えて平均粒径０．４μｍのアルミナ粒子とした塗工液Ａ７を用いた以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 2
In the preparation of the coating liquid A, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid A7 in which alumina particles having an average particle diameter of 0.4 μm were used instead of the plate boehmite was used.
比較例３
　塗工液Ａの調製において、液粘度を８ｍＰａ・ｓに調整した塗工液Ａ８を用いた以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 3
In the preparation of the coating liquid A, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid A8 having a liquid viscosity adjusted to 8 mPa · s was used.
比較例４
　塗工液Ｂの調製において、液粘度を２０ｍＰａ・ｓに調整した塗工液Ｂ４を用いた以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 4
In the preparation of the coating liquid B, a battery separator was obtained in the same manner as in Example 1 except that the coating liquid B4 having a liquid viscosity adjusted to 20 mPa · s was used.
比較例５
　塗工液Ｂの調製において、略球状有機粒子分散液をメラミン・ホルムアルデヒド縮合物球状粒子（平均粒径０．４μｍ）の水分散液（固形分濃度１５質量％）に替えた塗工液Ｂ５を用いた以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 5
In the preparation of the coating liquid B, a coating liquid B5 obtained by replacing the substantially spherical organic particle dispersion with an aqueous dispersion (solid content concentration 15% by mass) of melamine / formaldehyde condensate spherical particles (average particle size 0.4 μm) is used. A battery separator was obtained in the same manner as in Example 1 except that it was used.
比較例６
　塗工液Ｂの塗工量を調整し、略球状有機粒子と板状無機粒子の総体積に対して略球状有機粒子の体積が５体積％となるようにした以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 6
The same procedure as in Example 1 was conducted except that the coating amount of the coating liquid B was adjusted so that the volume of the substantially spherical organic particles was 5% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles. Thus, a battery separator was obtained.
比較例７
　塗工液Ａを塗布する際にＳ／Ｆ比０．５０の条件とした以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 7
A battery separator was obtained in the same manner as in Example 1 except that the coating liquid A was applied under conditions of an S / F ratio of 0.50.
比較例８
　塗工液Ａ１を塗布する際にグラビアロールの回転方向をポリエチレン微多孔膜の搬送方向と同じにし、Ｓ／Ｆ比１．２５の条件で塗工液Ａ１を塗布した以外は実施例１と同様にして電池用セパレータを得た。 Comparative Example 8
Similar to Example 1 except that the rotation direction of the gravure roll is the same as the transport direction of the polyethylene microporous membrane when the coating liquid A1 is applied, and the coating liquid A1 is applied under the condition of S / F ratio of 1.25. Thus, a battery separator was obtained.
比較例９
　比較例１の電池用セパレータと同厚みのポリエチレン微多孔膜（空孔率２３％、透気抵抗度１１０秒／１００ｃｃ）を電池用セパレータとした。 Comparative Example 9
A polyethylene microporous membrane (porosity 23%, air permeability 110 seconds / 100 cc) having the same thickness as the battery separator of Comparative Example 1 was used as the battery separator.
　実施例１～１０及び比較例１～９で得られた電池用セパレータの特性を表１に示す。
　なお、多孔層の表面、及び断面を拡大観察した結果、実施例１～１０、及び、比較例３、５～７は略球状有機粒子が多孔層の表面に偏在し、板状無機粒子が島、略球状有機粒子を海とする海島構造であった。比較例１及び４は板状無機粒子と略球状有機粒子が混在し、海島構造ではなかった。 Table 1 shows the characteristics of the battery separators obtained in Examples 1 to 10 and Comparative Examples 1 to 9.
As a result of magnifying and observing the surface and cross section of the porous layer, in Examples 1 to 10 and Comparative Examples 3 and 5 to 7, substantially spherical organic particles are unevenly distributed on the surface of the porous layer, and the plate-like inorganic particles are islands. It was a sea-island structure with substantially spherical organic particles as the sea. In Comparative Examples 1 and 4, plate-like inorganic particles and substantially spherical organic particles were mixed, and the sea-island structure was not obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
１．略球状有機粒子
２．板状無機粒子
３．ポリオレフィン微多孔膜
４．ポリオレフィン微多孔膜の搬送方向
５．グラビアロール
６．グラビアロールの回転方向 1. 1. Spherical organic particles 2. Plate-like inorganic particles 3. Polyolefin microporous membrane 4. Transport direction of polyolefin microporous membrane Gravure roll6. Gravure roll rotation direction

Claims (7)

  1. ポリオレフィン微多孔膜と、少なくともその片面にアクリル系樹脂またはフッ素系樹脂からなる略球状有機粒子と板状無機粒子を含む多孔層と、を有し、
    前記略球状有機粒子が膜厚方向に対して前記多孔層の表面に偏在しており、
    前記略球状有機粒子の平均粒径ｒ（μｍ）と前記板状無機粒子の平均厚さｔ（μｍ）の比（ｒ／ｔ）が式１及び式２を満足する電池用セパレータ。
    　　０．１μｍ≦ｒ≦０．８μｍ・・・・式１
    　　０．３≦ｒ／ｔ≦１．０　　・・・・式２     A polyolefin microporous membrane, and a porous layer containing substantially spherical organic particles and plate-like inorganic particles made of acrylic resin or fluorine resin on at least one surface thereof,
    The substantially spherical organic particles are unevenly distributed on the surface of the porous layer with respect to the film thickness direction,
    A battery separator in which a ratio (r / t) of an average particle diameter r (μm) of the substantially spherical organic particles to an average thickness t (μm) of the plate-like inorganic particles satisfies Expressions 1 and 2.
    0.1 μm ≦ r ≦ 0.8 μm ... Formula 1
    0.3 ≦ r / t ≦ 1.0 Formula 2
  2. 前記板状無機粒子がアルミナまたはベーマイトである請求項１に記載の電池用セパレータ。 The battery separator according to claim 1, wherein the plate-like inorganic particles are alumina or boehmite.
  3. 前記略球状有機粒子の体積が前記略球状有機粒子と前記板状無機粒子の総体積に対して１０～３０体積％である請求項１又は２に記載の電池用セパレータ。 The battery separator according to claim 1 or 2, wherein the volume of the substantially spherical organic particles is 10 to 30% by volume with respect to the total volume of the substantially spherical organic particles and the plate-like inorganic particles.
  4. 前記電池用セパレータがリチウムイオン二次電池用セパレータである請求項１～３のいずれか１項に記載の電池用セパレータ。 The battery separator according to any one of claims 1 to 3, wherein the battery separator is a lithium ion secondary battery separator.
  5. 以下の工程（ａ）及び（ｂ）を順次含む、請求項１～４のいずれか１項に記載の電池用セパレータの製造方法。
    （ａ）ポリオレフィン微多孔膜に板状無機粒子を含む塗工液Ａをリバースグラビアコート法で塗布し、乾燥させ、板状無機粒子層を積層させる工程。
    （ｂ）前記板状無機粒子層上に電極材料との密着性を付与または向上させる樹脂からなる略球状有機粒子を含む塗工液Ｂをリバースグラビアコート法で塗布し、乾燥させ電池用セパレータを得る工程。     The method for producing a battery separator according to any one of claims 1 to 4, comprising the following steps (a) and (b) in sequence.
    (A) The process of apply | coating the coating liquid A containing a plate-shaped inorganic particle to a polyolefin microporous film by a reverse gravure coating method, and making it dry and laminating | stack a plate-shaped inorganic particle layer.
    (B) A coating liquid B containing substantially spherical organic particles made of a resin that imparts or improves adhesion to the electrode material on the plate-like inorganic particle layer is applied by a reverse gravure coating method and dried to provide a battery separator. Obtaining step.
  6. 前記塗工液Ａの粘度が１０～３０ｍＰａ・ｓである請求項５に記載の電池用セパレータの製造方法。 The method for producing a battery separator according to claim 5, wherein the coating liquid A has a viscosity of 10 to 30 mPa · s.
  7. 前記塗工液Ｂの粘度が１～１０ｍＰａ・ｓである請求項５または６に記載の電池用セパレータの製造方法。 The method for producing a battery separator according to claim 5 or 6, wherein the coating liquid B has a viscosity of 1 to 10 mPa · s.
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CN114024100B (en) * 2022-01-05 2022-04-15 湖南中锂新材料科技有限公司 Separator for nonaqueous electrolyte lithium secondary battery and nonaqueous electrolyte lithium secondary battery
KR102594964B1 (en) 2022-05-26 2023-10-26 주식회사 엘지에너지솔루션 A Separator having an organic/inorganic composite coating layer and an electrochemical device comprising the same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007066768A1 (en) * 2005-12-08 2007-06-14 Hitachi Maxell, Ltd. Separator for electrochemical device and method for producing same, and electrochemical device and method for manufacturing same
JP2011131470A (en) * 2009-12-24 2011-07-07 Sumitomo Chemical Co Ltd Laminated film and nonaqueous electrolyte secondary battery
JP2014137985A (en) * 2013-01-18 2014-07-28 Toyota Motor Corp Secondary battery
US20140308565A1 (en) * 2013-04-16 2014-10-16 Samsung Sdi Co, Ltd. Separator and lithium battery including the separator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5530353B2 (en) * 2008-06-09 2014-06-25 日立マクセル株式会社 Porous membrane for separator, battery separator, battery electrode and manufacturing method thereof, and lithium secondary battery
JP2014517580A (en) 2011-05-06 2014-07-17 富士通株式会社 Transmission mode setting method, user equipment and base station
JP5751414B2 (en) * 2011-07-11 2015-07-22 日本ゼオン株式会社 Slurry composition for secondary battery porous membrane
US10803970B2 (en) 2011-11-14 2020-10-13 Seagate Technology Llc Solid-state disk manufacturing self test
JPWO2013080701A1 (en) * 2011-12-02 2015-04-27 三菱樹脂株式会社 Laminated porous film roll and method for producing the same
JP6281220B2 (en) * 2013-09-26 2018-02-21 日本ゼオン株式会社 Manufacturing method of heat-resistant separator for secondary battery
JP5702873B2 (en) * 2014-04-04 2015-04-15 日立マクセル株式会社 Electrochemical element separator, electrochemical element and method for producing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007066768A1 (en) * 2005-12-08 2007-06-14 Hitachi Maxell, Ltd. Separator for electrochemical device and method for producing same, and electrochemical device and method for manufacturing same
JP2011131470A (en) * 2009-12-24 2011-07-07 Sumitomo Chemical Co Ltd Laminated film and nonaqueous electrolyte secondary battery
JP2014137985A (en) * 2013-01-18 2014-07-28 Toyota Motor Corp Secondary battery
US20140308565A1 (en) * 2013-04-16 2014-10-16 Samsung Sdi Co, Ltd. Separator and lithium battery including the separator

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018510472A (en) * 2015-04-02 2018-04-12 エスケー イノベーション カンパニー リミテッドＳｋ Ｉｎｎｏｖａｔｉｏｎ Ｃｏ．，Ｌｔｄ． Fusion composite separation membrane for lithium secondary battery and method for producing the same
JP7073105B2 (en) 2015-04-02 2022-05-23 エスケー イノベーション カンパニー リミテッド Fusion type composite separation membrane for lithium secondary battery and its manufacturing method
US10985356B2 (en) 2015-04-02 2021-04-20 Sk Innovation Co., Ltd. Composite separation membrane for lithium secondary battery and manufacturing method therefor
JP2018190722A (en) * 2017-04-28 2018-11-29 住友化学株式会社 Insulating porous layer for nonaqueous electrolyte secondary battery
JPWO2019003770A1 (en) * 2017-06-30 2020-03-19 日立オートモティブシステムズ株式会社 Secondary battery and method of manufacturing the same
JPWO2019065845A1 (en) * 2017-09-29 2020-09-10 東レ株式会社 Method for manufacturing porous composite film, battery separator, and porous composite film
WO2019065845A1 (en) * 2017-09-29 2019-04-04 東レ株式会社 Porous composite film, separator for battery, and method for manufacturing porous composite film
JP7160034B2 (en) 2017-09-29 2022-10-25 東レ株式会社 Porous composite film, battery separator, and method for producing porous composite film
KR102207528B1 (en) * 2017-12-15 2021-01-26 주식회사 엘지화학 POROUS SEPARATING FiLM AND ELECTROCHEMICAL DEVICE CONTAINING THE SAME
KR20190072479A (en) * 2017-12-15 2019-06-25 주식회사 엘지화학 POROUS SEPARATING FiLM AND ELECTROCHEMICAL DEVICE CONTAINING THE SAME
US11411282B2 (en) 2017-12-15 2022-08-09 Lg Energy Solution, Ltd. Porous separator including porous layer including plate-type inorganic particles and porous coating layer including spherical inorganic particles and electrochemical device including the same
WO2019117687A1 (en) * 2017-12-15 2019-06-20 주식회사 엘지화학 Porous separator and electrochemical device comprising same
CN110233223A (en) * 2018-03-06 2019-09-13 三星Sdi株式会社 Partition, the method for preparing partition and the lithium battery including partition
US11502373B2 (en) 2018-03-06 2022-11-15 Samsung Sdi Co., Ltd. Separator, method of preparing the same, and lithium battery including the same
CN110233223B (en) * 2018-03-06 2022-10-11 三星Sdi株式会社 Separator, method of preparing the same, and lithium battery including the same
JP2019160408A (en) * 2018-03-07 2019-09-19 トヨタ自動車株式会社 Battery and manufacturing method therefor
JP7032180B2 (en) 2018-03-07 2022-03-08 トヨタ自動車株式会社 Batteries and their manufacturing methods
US12002990B2 (en) 2018-10-12 2024-06-04 Lg Energy Solution, Ltd. Porous separator and lithium secondary battery comprising same
WO2020105673A1 (en) 2018-11-22 2020-05-28 東レ株式会社 Porous film, separator for secondary cell, and secondary cell
KR20210092191A (en) 2018-11-22 2021-07-23 도레이 카부시키가이샤 Porous film, secondary battery separator and secondary battery
JP2022542567A (en) * 2019-07-30 2022-10-05 エルジー・ケム・リミテッド Composite separation membrane for electrochemical device and electrochemical device including the same
US20220263194A1 (en) * 2019-07-30 2022-08-18 Lg Chem, Ltd. Composite separator for electrochemical device and electrochemical device including the same
EP3996183A4 (en) * 2019-07-30 2023-01-04 LG Chem, Ltd. Composite separator for electrochemical device, and electrochemical device including same
JP7372438B2 (en) 2019-07-30 2023-10-31 エルジー・ケム・リミテッド Composite separation membrane for electrochemical devices and electrochemical devices containing the same
US12266821B2 (en) * 2019-07-30 2025-04-01 Lg Chem, Ltd. Composite separator for electrochemical device and electrochemical device including the same
WO2021085144A1 (en) * 2019-10-31 2021-05-06 日本ゼオン株式会社 Functional layer for electrochemical elements and method for producing same, separator with functional layer for electrochemical elements and method for producing same, and electrochemical element and method for producing same

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