WO2015046126A1 - Porous layer for nonaqueous batteries, separator for nonaqueous batteries, electrode for nonaqueous batteries, and nonaqueous battery - Google Patents

Porous layer for nonaqueous batteries, separator for nonaqueous batteries, electrode for nonaqueous batteries, and nonaqueous battery Download PDF

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Publication number
WO2015046126A1
WO2015046126A1 PCT/JP2014/075033 JP2014075033W WO2015046126A1 WO 2015046126 A1 WO2015046126 A1 WO 2015046126A1 JP 2014075033 W JP2014075033 W JP 2014075033W WO 2015046126 A1 WO2015046126 A1 WO 2015046126A1
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porous layer
separator
nonaqueous
battery
fine particles
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PCT/JP2014/075033
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French (fr)
Japanese (ja)
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松本　修明
正也 船橋
祐介 高取
壽夫 神崎
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日立マクセル株式会社
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Priority to JP2015539197A priority Critical patent/JPWO2015046126A1/en
Publication of WO2015046126A1 publication Critical patent/WO2015046126A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—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
    • 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
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M50/489—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

Definitions

  • the present invention relates to a non-aqueous battery having high safety and a porous layer, a separator and an electrode for constituting the non-aqueous battery.
  • a lithium secondary battery which is a type of non-aqueous battery, is widely used as a power source for portable devices such as mobile phones and notebook personal computers because of its high energy density. As the performance of portable devices increases, the capacity of lithium secondary batteries tends to increase further, and it is important to ensure safety.
  • a polyolefin-based porous film having a thickness of, for example, about 15 to 30 ⁇ m is used as a separator interposed between a positive electrode and a negative electrode.
  • separator material the constituent resin of the separator is melted below the thermal runaway temperature of the battery to close the pores, thereby increasing the internal resistance of the battery and improving the safety of the battery in the event of a short circuit.
  • polyethylene having a low melting point may be applied.
  • a separator for example, a uniaxially stretched film or a biaxially stretched film is used for increasing the porosity and improving the strength. Since such a separator is supplied as a single film, a certain strength is required in terms of workability and the like, and this is secured by the stretching. However, with such a stretched film, the degree of crystallinity has increased, and the shutdown temperature has increased to a temperature close to the thermal runaway temperature of the battery. Therefore, it can be said that the margin for ensuring the safety of the battery is sufficient. hard.
  • the film is distorted by the stretching, and when it is exposed to high temperature, there is a problem that shrinkage occurs due to residual stress.
  • the shrinkage temperature is very close to the shutdown temperature.
  • the current when the battery temperature reaches the shutdown temperature in the case of abnormal charging, the current must be immediately decreased to prevent the battery temperature from rising. This is because if the pores are not sufficiently closed and the current cannot be reduced immediately, the battery temperature easily rises to the contraction temperature of the separator, and there is a risk of ignition due to an internal short circuit.
  • Patent Documents 1 and 2 include a technique for improving heat resistance on the surface of a porous resin film containing a thermoplastic resin. It has been proposed to use a separator having a heat-resistant porous layer.
  • Patent Documents 1 and 2 it is possible to provide a nonaqueous electrolyte battery that is less likely to cause thermal runaway even when abnormally overheated, and that is excellent in safety and reliability.
  • Patent Document 3 discloses that a specific amount of N-vinylacetamide polymer or water-soluble cellulose derivative and a specific amount as a binder for binding the heat-resistant fine particles as the main component in the heat-resistant porous layer.
  • the separator which can improve the reliability of the battery further compared with the separator of patent document 1 and patent document 2 by using together with the crosslinked acrylic resin of this is disclosed.
  • the polymer of N-vinylacetamide has room for improvement with respect to the resistance to the non-aqueous electrolyte in a high temperature environment.
  • This invention is made
  • the objective is providing the non-aqueous battery which has high safety
  • the porous layer for a nonaqueous battery of the present invention that has achieved the above object is a porous layer for a nonaqueous battery containing fine particles having an allowable temperature limit of 150 ° C. or more and an organic binder, and the organic binder includes: A copolymer of an N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the following general formula (2), the N-vinylcarboxylic acid in the copolymer: The copolymerization ratio of the acid amide and the unsaturated carboxylic acid monomer is 50:50 to 95: 5 by mass ratio.
  • R 1 and R 2 each independently represent a hydrogen atom or a methyl group
  • R 3 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
  • R 4 represents a hydrogen atom, a methyl group or —COOM 2
  • R 5 represents a hydrogen atom, a methyl group or —COOM 3
  • M 1 , M 2 and M 3 each independently represent hydrogen.
  • An atom, an alkali metal, an alkaline earth metal, an ammonium group or an organic amino group is represented, and n is 0 or 1.
  • the separator for nonaqueous batteries of the present invention is characterized in that the porous layer for nonaqueous batteries of the present invention is formed on a porous resin film.
  • the electrode for nonaqueous battery of the present invention is characterized in that a porous layer for nonaqueous battery is formed on an electrode mixture layer.
  • the nonaqueous battery of the present invention includes (a) a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte, and the separator is the nonaqueous battery separator of the present invention, or (b) a positive electrode, a negative electrode And at least one of the positive electrode and the negative electrode is a nonaqueous battery electrode of the present invention.
  • heat-resistant temperature is 150 ° C. or higher” means that deformation such as softening is not observed at least at 150 ° C.
  • non-aqueous battery having high safety, and a porous layer, a separator, and an electrode for constituting the non-aqueous battery.
  • porous layer for non-aqueous batteries of the present invention (hereinafter sometimes simply referred to as “porous layer”) is used as a separator for separating the positive electrode and the negative electrode in the non-aqueous battery, and has a heat resistant temperature. It contains fine particles of 150 ° C. or higher and an organic binder, and the fine particles are bound together by the organic binder.
  • the separator for a non-aqueous battery of the present invention By forming the porous layer of the present invention on the porous resin film, the separator for a non-aqueous battery of the present invention can be constituted, and on the electrode mixture layer of the electrode (positive electrode or negative electrode) of the non-aqueous battery.
  • the nonaqueous battery electrode of the present invention can be configured.
  • the organic binder binds the constituent components (such as fine particles having a heat resistant temperature of 150 ° C. or higher) in the porous layer, and the porous layer and the porous resin film. And are adhered.
  • the organic binder binds the constituent components (such as fine particles having a heat resistant temperature of 150 ° C. or higher) in the porous layer, and the porous layer and the electrode.
  • the electrode mixture layer is adhered.
  • a copolymer of N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the general formula (2) The copolymerization ratio of the N-vinylcarboxylic amide and the unsaturated carboxylic acid monomer is 50:50 to 95: 5 by mass.
  • a polymer having N-vinylcarboxylic acid amide represented by the general formula (1) as a monomer, such as poly N-vinylacetamide, may be used in a nonaqueous electrolysis that is employed in a normal nonaqueous battery depending on its composition.
  • a high temperature of 100 ° C. or higher in a liquid (non-aqueous electrolyte solvent) the adhesiveness may decrease.
  • a porous layer using this as a binder for example, the binding state of components May not be maintained satisfactorily, and the assumed characteristics (mainly heat resistance) may not be sufficiently ensured.
  • the present inventors have obtained a structural part derived from the N-vinylcarboxylic acid amide represented by the general formula (1) and a structural part derived from the unsaturated carboxylic acid monomer represented by the general formula (2). It has been found that a copolymer containing a specific ratio can increase resistance to a high-temperature non-aqueous electrolyte compared to poly N-vinylacetamide and the like, and based on this finding, the copolymer is made porous. By using it as an organic binder for the layer, it was found that higher safety (safety at a high temperature such as 100 ° C. or higher) than before can be imparted to the nonaqueous battery, and the present invention has been completed.
  • N-vinylcarboxylic amide represented by the general formula (1) examples include N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylformamide, N-methyl-N-vinylacetamide and the like. Among them, one or more of them can be used for the synthesis of the copolymer. Of these, N-vinylacetamide is particularly preferred.
  • Examples of the unsaturated carboxylic acid monomer represented by the general formula (2) include acrylic acid, methacrylic acid, acrylates (alkali metal salts such as sodium salts and potassium salts), methacrylates ( Sodium salts, alkali salts such as potassium salts, etc.) are preferred, and one or more of them can be used for the synthesis of the copolymer.
  • alkali metal salts of acrylic acid and alkali metal salts of methacrylic acid are particularly preferable.
  • the copolymer composition is the above N-vinyl.
  • the ratio of the unsaturated carboxylic acid monomer is 5% by mass or more, preferably 7% by mass or more, More preferably, it is 10% by mass or more (that is, the proportion of the N-vinylcarboxylic amide is 95% by mass or less, preferably 93% by mass or less, and more preferably 90% by mass or less. preferable).
  • a copolymer having such a copolymer composition resistance in a high-temperature non-aqueous electrolyte solvent is improved, and its adhesive strength is less likely to be impaired.
  • a porous layer capable of constituting a battery can be formed.
  • the copolymer of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) is derived from the unsaturated carboxylic acid monomer. If the amount of the component is too large, the hygroscopicity of the copolymer may increase, and the battery characteristics of the nonaqueous battery using the porous layer may be impaired. In addition to the polymer, a composition containing fine particles or a solvent having a heat resistant temperature of 150 ° C. or higher (details will be described later)) may increase the viscosity too much, thereby impairing the coatability.
  • the copolymer composition is When the total of N-vinylcarboxylic acid amide and the unsaturated carboxylic acid monomer is 100% by mass, the ratio of the unsaturated carboxylic acid monomer is 50% by mass or less and 30% by mass or less. (Ie, the proportion of the N-vinylcarboxylic acid amide is 50% by mass or more, and preferably 70% by mass or more).
  • the molecular weight of the copolymer of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) was determined using gel permeation chromatography.
  • the number average molecular weight (polystyrene equivalent value) measured is preferably 30,000 or more, more preferably 50,000 or more, preferably 5,000,000 or less, more preferably 3,000,000 or less. More preferably, it is 2,000,000 or less.
  • a copolymer having a ratio of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) within the above range is used as the organic binder.
  • the organic binder absorbs moisture, compared to the case where an organic binder is used as the copolymer in which the unsaturated carboxylic acid monomer is too much.
  • the water content of the separator as a whole is 1500 ppm or less. Is preferred.
  • the moisture content of the separator referred to in this specification can be measured by the following method.
  • a separator sample for measurement is allowed to stand in a glove box having a dew point of ⁇ 50 ° C. for 12 hours or more, and then the measurement sample is placed in a heating furnace at 150 ° C. in which nitrogen gas is flowed and held for 1 minute. Then, the flowd nitrogen gas is introduced into the measurement cell of the Karl Fischer moisture meter, and the moisture content is measured. The integrated value up to the titration end point is taken as the moisture content.
  • the measurement is performed in a glove box having a dew point of ⁇ 50 ° C., and the water content per unit mass of the separator (unit: ppm) is calculated by dividing the measured value by the mass of the sample.
  • the copolymer of the N-vinylcarboxylic amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) is ethylene, propylene, vinyl alcohol, acetic acid. It can further include other ethylenically unsaturated monomer components such as vinyl, acrylonitrile, or derivatives thereof. However, in order not to inhibit the above action, the ratio is desirably 20% by mass or less of the entire copolymer.
  • an organic binder a copolymer of an N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the general formula (2) is used.
  • other organic binders may be used together with the copolymer. Examples of such other organic binders include ethylene-vinyl acetate copolymers (EVA, those having a structural unit derived from vinyl acetate of 20 to 35 mol%), (meth) acrylate polymers [“(meth) acrylates”. "Means including acrylate and methacrylate.
  • Fluorinated rubber styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), polyurethane, poly N-vinylacetamide (N-vinylacetamide homopolymer), etc. And one or more of these can be used.
  • SBR styrene butadiene rubber
  • PVA polyvinyl alcohol
  • PVB polyvinyl butyral
  • PVP polyvinyl pyrrolidone
  • polyurethane poly N-vinylacetamide (N-vinylacetamide homopolymer), etc. And one or more of these can be used.
  • the content of the organic binder other than is preferably 10% by mass or less.
  • the fine particles having a heat-resistant temperature of 150 ° C. or more are short-circuited due to lithium dendrite by becoming a main component in the porous layer of the present invention or filling voids formed between fibrous materials described later. Has the effect of suppressing the occurrence.
  • the fine particles having a heat-resistant temperature of 150 ° C. or higher have electrical insulating properties, are electrochemically stable, and further contain a non-aqueous electrolyte and porous layer forming composition (composition containing a solvent) described later. There is no particular limitation as long as it is stable to the solvent used in the above and is stable at high temperatures and has high heat resistance.
  • stable to non-aqueous electrolyte means deformation and chemical composition change in non-aqueous electrolyte (non-aqueous electrolyte used as non-aqueous battery electrolyte). It means not.
  • the “high temperature state” in the present specification is specifically a temperature of 150 ° C. or higher, and is a stable particle that does not undergo deformation or chemical composition change in a non-aqueous electrolyte at such a temperature. I just need it.
  • electrochemically stable as used in the present specification means that no chemical change occurs during charging / discharging of the battery.
  • Such fine particles having a heat resistant temperature of 150 ° C. or higher include, for example, oxide fine particles such as iron oxide, SiO 2 , Al 2 O 3 , TiO 2 , BaTiO 3 , ZrO 2 , MgO; aluminum nitride, Nitride fine particles such as silicon nitride; poorly soluble ionic crystal fine particles such as calcium fluoride, barium fluoride and barium sulfate; covalently bonded crystal fine particles such as silicon and diamond; clay fine particles such as talc and montmorillonite; boehmite, zeolite, Examples thereof include inorganic fine particles such as substances derived from mineral resources such as apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, hydrotalcite, or artificial products thereof.
  • oxide fine particles such as iron oxide, SiO 2 , Al 2 O 3 , TiO 2 , BaTiO 3 , ZrO 2 , MgO
  • the surface of conductive fine particles such as metal fine particles; oxide fine particles such as SnO 2 and tin-indium oxide (ITO); carbonaceous fine particles such as carbon black and graphite; Fine particles imparted with electrical insulation properties may be obtained by surface treatment with the above-mentioned materials that constitute fine particles having an electrical insulating heat-resistant temperature of 150 ° C. or higher.
  • organic fine particles can be used for the fine particles having a heat resistant temperature of 150 ° C. or higher.
  • organic fine particles include polyimide, melamine resin, phenolic resin, crosslinked polymethyl methacrylate (crosslinked PMMA), crosslinked polystyrene (crosslinked PS), polydivinylbenzene (PDVB), benzoguanamine-formaldehyde condensate, etc.
  • the organic resin (polymer) constituting these organic fine particles is a mixture, modified body, derivative, copolymer (random copolymer, alternating copolymer, block copolymer, graft copolymer) of the materials exemplified above. ) Or a crosslinked product (in the case of the heat-resistant polymer).
  • These fine particles having a heat-resistant temperature of 150 ° C. or higher may be used alone or in combination of two or more.
  • oxide or hydroxide fine particles such as SiO 2 , Al 2 O 3 and boehmite are particularly preferable.
  • the form of the fine particles having a heat resistant temperature of 150 ° C. or higher may be any form such as a spherical shape, a particle shape, or a plate shape, but a plate shape is preferable.
  • the plate-like particles include various commercially available products. For example, “Sun Green” (SiO 2 ) manufactured by Asahi Glass Stech Co., Ltd., “NST-B1” pulverized product (TiO 2 ) manufactured by Ishihara Sangyo Co., Ltd., Sakai Chemical Industry Co., Ltd.
  • the fine particles having a heat resistant temperature of 150 ° C. or higher are plate-like, the fine particles having a heat resistant temperature of 150 ° C. or higher are oriented in the porous layer so that the flat plate surface is substantially parallel to the surface of the porous layer. It is preferable to use a separator having such a porous layer, and the occurrence of a short circuit of the battery can be suppressed more favorably. This is because the fine particles having a heat-resistant temperature of 150 ° C. or more are oriented as described above, and the fine particles having a heat-resistant temperature of 150 ° C. or more are arranged so as to overlap each other on a part of the flat plate surface.
  • the gap (through hole) from the surface to the other surface is formed in a curved shape rather than a straight line (that is, the curvature becomes large), and this allows the lithium dendrite to penetrate the porous layer. Since it can prevent, it is estimated that generation
  • the aspect ratio (the ratio of the maximum length in the plate-like particles to the thickness of the plate-like particles) is 5 or more as the form when the fine particles having a heat-resistant temperature of 150 ° C. or higher are plate-like particles.
  • it is 10 or more, more preferably 100 or less, and even more preferably 50 or less.
  • the average value of the ratio of the major axis direction length to the minor axis direction length of the flat plate surface of the grains is preferably 0.3 or more, more preferably 0.5 or more (ie, the major axis length).
  • the length in the minor axis direction may be the same).
  • the average value of the ratio of the long axis direction length to the short axis direction length of the flat plate surface when the fine particles having a heat resistant temperature of 150 ° C. or more are plate-like is taken by, for example, a scanning electron microscope (SEM) It can obtain
  • the aspect ratio in the case where the fine particles having a heat resistant temperature of 150 ° C. or higher are plate-like can also be obtained by image analysis of an image taken by SEM.
  • the fine particles having a heat resistant temperature of 150 ° C. or higher may be particles containing two or more materials constituting the fine particles having various heat resistant temperatures exemplified above of 150 ° C. or higher.
  • the average particle diameter of the fine particles having a heat resistant temperature of 150 ° C. or higher is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more, preferably 15 ⁇ m or less, more preferably 5 ⁇ m or less.
  • the average particle size of the fine particles having a heat resistant temperature of 150 ° C. or higher is determined by, for example, using a laser scattering particle size distribution meter (for example, “LA-920” manufactured by HORIBA) to It can be defined as the number average particle diameter measured by dispersing fine particles having a heat resistant temperature of 150 ° C. or higher in a medium in which the fine particles having a heat resistant temperature of 150 ° C. or higher do not swell.
  • a laser scattering particle size distribution meter for example, “LA-920” manufactured by HORIBA
  • the specific surface area of the fine particles having a heat resistant temperature of 150 ° C. or higher is preferably 100 m 2 / g or less, more preferably 50 m 2 / g or less, and further preferably 30 m 2 / g or less. If the specific surface area is too large, the amount of the binder for binding fine particles to each other, or binding the fine particles to the substrate or electrode may be too large, and the output characteristics may be deteriorated when the battery is used. In addition, there is a possibility that the moisture adsorbed on the surface of the fine particles increases and the battery characteristics of the nonaqueous battery are deteriorated.
  • a preferable lower limit value of the specific surface area of the fine particles having a heat resistant temperature of 150 ° C. or higher is 1 m 2 / g.
  • the specific surface area is a value measured by a BET method using nitrogen gas.
  • the porous layer of the present invention uses fine particles having a high heat resistance temperature of 150 ° C. or higher as described above, its action can suppress thermal shrinkage at high temperatures and improve dimensional stability. .
  • the porous layer of the present invention containing fine particles having a high heat resistance of 150 ° C. or higher is integrated with an electrode (positive electrode or negative electrode), the dimensions of the porous layer at a high temperature Stability can be further enhanced.
  • the porous resin film is dimensional stability at high temperatures. Even if it is inferior to the above, since it is integrated with a porous layer having good dimensional stability at high temperature by the action of fine particles having a heat resistant temperature of 150 ° C. or higher, thermal shrinkage of the porous resin film is suppressed, The overall dimensional stability of the separator at high temperatures is improved.
  • the separator of the present invention using the porous layer of the present invention for example, the occurrence of a short circuit due to heat shrinkage that occurred in a separator composed only of a conventional PE porous film (PE microporous film). Therefore, the reliability and safety when the inside of the battery is abnormally overheated can be further improved.
  • PE porous film PE microporous film
  • the porous layer of the present invention may contain a fibrous material having a heat resistant temperature of 150 ° C. or higher.
  • the fibrous material is included from the viewpoint of reinforcing the porous layer and improving its handleability. It is preferable that the fibrous material is the main component of the separator.
  • a separator is constituted by a porous layer and a porous resin film, or when the porous layer is integrated with an electrode, a fibrous material having a heat resistant temperature of 150 ° C. or more is contained for reinforcement. be able to.
  • the porous layer contains a material that can be melted at a temperature of 140 ° C. or lower to block the pores of the porous layer (separator) and provide a function of blocking the movement of ions in the separator (so-called shutdown function).
  • a fibrous material having a heat-resistant temperature of 150 ° C. or higher is also contained in the porous layer. Even if the temperature rises, the shape can be kept more stable.
  • a separator configured using a porous layer that also uses a fibrous material having a heat resistant temperature of 150 ° C. or higher substantially does not deform even at a temperature of 150 ° C. Can be eliminated.
  • the fibrous material has a heat resistant temperature of 150 ° C. or higher, has an electrical insulating property, is electrochemically stable, and further has an electrolyte solution described in detail below and fine particles having a heat resistant temperature of 150 ° C. or higher. If it is stable to the solvent used for the composition for forming a porous layer containing the above, there is no particular limitation.
  • the “fibrous material” in the present specification means that having an aspect ratio [length in the longitudinal direction / width (diameter) in a direction perpendicular to the longitudinal direction] of 4 or more.
  • the aspect ratio of the fibrous material is preferably 10 or more.
  • constituent materials of the fibrous material include, for example, cellulose, modified cellulose (such as carboxymethyl cellulose), polypropylene (PP), polyester [polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT). And the like], resins such as polyacrylonitrile (PAN), aramid, polyamideimide, and polyimide; inorganic materials (inorganic oxides) such as glass, alumina, and silica; and the like.
  • the fibrous material may contain one kind of these constituent materials, or may contain two or more kinds.
  • the fibrous material may contain various known additives (for example, an antioxidant in the case of a resin) as necessary. Absent.
  • the fibrous material may be subjected to a surface treatment such as a corona discharge treatment or a treatment with a surfactant in order to enhance the adhesion with fine particles having a heat resistant temperature of 150 ° C. or higher.
  • a surface treatment such as a corona discharge treatment or a treatment with a surfactant in order to enhance the adhesion with fine particles having a heat resistant temperature of 150 ° C. or higher.
  • the diameter of the fibrous material may be equal to or less than the thickness of the porous layer, but is preferably 0.01 to 5 ⁇ m, for example. If the diameter is too large, the entanglement between the fibrous materials may be insufficient, and the strength of the sheet-like material constituted by these, and consequently the strength of the porous layer may be reduced, making it difficult to handle. On the other hand, if the diameter is too small, the pores of the porous layer become too small, and the ion permeability tends to decrease, which may reduce the load characteristics of the battery.
  • the fibrous material may be contained in the porous layer in a state where each fibrous material is independent, and the porous layer in a sheet-like material (woven fabric, non-woven fabric, etc.) composed of the fibrous material. It may be included.
  • the state of the fibrous material in the porous layer is preferably such that the angle of the long axis (axis in the long direction) to the separator surface is 30 ° or less on average, 20 °
  • the angle of the long axis (axis in the long direction) to the separator surface is 30 ° or less on average, 20 °
  • the following is more preferable.
  • the content of the fine particles having a heat resistant temperature of 150 ° C. or higher in the porous layer is the total volume of the constituent components of the porous layer from the viewpoint of more effectively exerting the effect of using the fine particles having a heat resistant temperature of 150 ° C. or higher. (The total volume excluding the void portion. The same applies hereinafter for the content of each component of the porous layer.) It is preferably 10% by volume or more, more preferably 30% by volume or more, and 40% by volume. It is still more preferable that it is above.
  • the porous layer does not contain the fibrous material and includes a heat-fusible fine particle or a swellable fine particle, which will be described later, and has a shutdown function
  • the fine particle having a heat resistant temperature of 150 ° C. or higher is used.
  • the upper limit of the volume ratio is preferably 80% by volume, for example.
  • the volume ratio of the fine particles having a heat-resistant temperature of 150 ° C. or higher may be higher, for example, 99.5% by volume or less.
  • a fine particle having a heat resistant temperature of 150 ° C. or higher is used.
  • the upper limit of the volume ratio is preferably 70% by volume, for example.
  • the volume ratio of the fine particles having a heat resistant temperature of 150 ° C. or higher may be a higher ratio, for example, 80% by volume or less.
  • the content of the fibrous material in the porous layer is the configuration of the porous layer from the viewpoint of more effectively exerting the effect of using the fibrous material.
  • the total volume of the components is preferably 10% by volume or more, and more preferably 30% by volume or more.
  • the content of the fibrous material is preferably 90% by volume or less and more preferably 70% by volume or less in the total volume of the constituent components of the porous layer. preferable.
  • the content of the organic binder in the porous layer is preferably 0.5% by mass or more in the total amount of the constituent components of the porous layer from the viewpoint of satisfactorily exerting the action of these organic binders.
  • the content of the organic binder is too large, the content of other components (such as fine particles having a heat-resistant temperature of 150 ° C. or higher) decreases, and the action of these other components may be reduced.
  • the content of the organic binder in the layer is preferably 10% by mass or less in the total amount of the constituent components of the porous layer.
  • a shutdown function can be imparted to the porous layer of the present invention.
  • the porous layer swells in hot-melt fine particles that melt at 80 to 150 ° C. or in a non-aqueous electrolyte, and the degree of swelling increases with an increase in temperature. What is necessary is just to contain the swelling fine particle which increases. It should be noted that both the hot-melt fine particles and the swellable fine particles may be added to the porous layer, or a composite of these may be added.
  • the shutdown function in the porous layer can be evaluated by, for example, an increase in resistance due to the temperature of the model cell. That is, a positive electrode, a negative electrode, and an electrolytic solution are provided, and a porous layer is provided on an electrode mixture layer of at least one of the positive electrode and the negative electrode, or a positive electrode, a negative electrode, a separator, and an electrolytic solution are provided, and the separator A model cell having a porous layer on at least one side of the sample cell was prepared, the model cell was held in a high-temperature bath, and the internal resistance value of the model cell was measured while increasing the temperature at a rate of 5 ° C./min.
  • this temperature can be evaluated as the shutdown temperature of the porous layer (of the present invention described later)
  • the same shutdown method can be used for the nonaqueous battery separator).
  • a porous material containing a heat-meltable fine particle that melts at 80 to 150 ° C. that is, a material having a melting temperature of 80 to 150 ° C. measured using a differential scanning calorimeter (DSC) according to JIS K 7121.
  • DSC differential scanning calorimeter
  • the shutdown temperature of the porous layer evaluated by the increase in internal resistance is not less than the melting point of the heat-meltable fine particles and not more than 150 ° C.
  • the melting point (the melting temperature) of the heat-meltable fine particles is more preferably 140 ° C. or lower.
  • the constituent material of the heat-meltable fine particles include polyethylene (PE), copolymerized polyolefin having a structural unit derived from ethylene of 85 mol% or more, polypropylene (PP), or polyolefin derivative (chlorinated polyethylene, chlorinated polypropylene, etc. ), Polyolefin wax, petroleum wax, carnauba wax and the like.
  • the copolymer polyolefin include an ethylene-vinyl monomer copolymer, more specifically, an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, or an ethylene-ethyl acrylate copolymer. it can.
  • the heat-meltable fine particles may have only one kind of these constituent materials, or may have two or more kinds.
  • PE polyolefin wax, or EVA having a structural unit derived from ethylene of 85 mol% or more is preferable.
  • the heat-meltable fine particles may contain various known additives (for example, antioxidants) added to the resin as necessary, in addition to the above-described constituent materials. Absent.
  • the particle diameter of the heat-meltable fine particles is a number average particle diameter measured by the same measurement method as fine particles having a heat resistant temperature of 150 ° C. or higher, and is preferably 0.001 ⁇ m or more, for example, 0.1 ⁇ m or more. More preferably, it is preferably 15 ⁇ m or less, and more preferably 1 ⁇ m or less.
  • the non-aqueous electrolysis is caused by swelling of the swellable fine particles when the inside becomes high temperature. It absorbs the liquid and expands greatly (hereinafter, the function of increasing the degree of swelling as the temperature rises in the swellable fine particles is called “thermal swellability”), thereby significantly increasing the conductivity of Li ions in the porous layer. Therefore, the internal resistance of the battery is increased, and the shutdown function can be reliably ensured.
  • the swellable fine particles those having a temperature showing the above-mentioned heat swellability are preferably 75 to 135 ° C.
  • swellable fine particles having thermal swellability examples include cross-linked polystyrene (PS), cross-linked acrylic resin [for example, cross-linked polymethyl methacrylate (PMMA)], cross-linked fluororesin [for example, cross-linked polyvinylidene fluoride (PVDF) ] Is preferred, and cross-linked PMMA is particularly preferred.
  • PS cross-linked polystyrene
  • PMMA cross-linked acrylic resin
  • PVDF cross-linked fluororesin
  • PVDF cross-linked polyvinylidene fluoride
  • the particle size of the swellable fine particles is a number average particle size measured by dispersing the fine particles in a non-swelling medium (for example, water) using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA). It is preferably 1 to 20 ⁇ m.
  • cross-linked PMMA As commercially available products of swellable fine particles, for example, cross-linked PMMA “Gantz Pearl (product name)” manufactured by Ganz Kasei Co., Ltd., and cross-linked PMMA “RSP1079 (product name)” manufactured by Toyo Ink Co., Ltd. are available.
  • the thermal meltable fine particle and / or swelling in the porous layer is required in order to ensure a good shutdown function.
  • the content of the conductive fine particles is preferably 5 to 70% by volume in the total volume of the constituent components of the porous layer. If the content of these fine particles is too small, the shutdown effect due to the inclusion of these may be reduced, and if too large, the content of fine particles or fibrous materials having a heat resistance temperature of 150 ° C. or higher in the porous layer. Therefore, the effect secured by these may be reduced.
  • the thickness of the porous layer of the present invention is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, further preferably 2 ⁇ m or more, and preferably 10 ⁇ m or less, preferably 5 ⁇ m or less. It is more preferable that
  • the porosity of the porous layer of the present invention is preferably 20 to 60%.
  • a i ratio of the component i expressed by mass%
  • ⁇ i density of the component i (g / cm 3 )
  • m mass per unit area of the porous layer (g / Cm 2 )
  • t thickness of the porous layer (cm).
  • the porous layer of the present invention is for forming a porous layer containing fine particles having an heat-resistant temperature of 150 ° C. or more and an organic binder, as well as fibrous materials, heat-meltable fine particles, swellable fine particles and the like used as necessary.
  • the composition (composition containing a solvent) is used on a porous resin film (in the case of the separator for a non-aqueous battery of the present invention) as a base material, or an electrode mixture layer of the electrode for a non-aqueous battery (of the present invention).
  • the electrode can be formed on a nonaqueous battery electrode) and then dried.
  • the porous layer forming composition is impregnated with the sheet, and the gap is formed as necessary.
  • the composition for forming a porous layer is promoted to penetrate into the voids of the sheet-like material, or the composition for forming a porous layer is applied to the sheet-like material through the gap after being applied. It is also possible to form a porous layer through a step of drying after intruding into the voids of the sheet-like material.
  • the composition for forming a porous layer contains fine particles having an heat resistant temperature of 150 ° C. or more and an organic binder, as well as fibrous materials, hot-melt fine particles, swellable fine particles, and the like, which are used as necessary. (Including a dispersion medium, the same shall apply hereinafter).
  • the organic binder can be dissolved in a solvent.
  • the solvent used in the composition for forming a porous layer may be any solvent as long as it can uniformly disperse the fine particles, and can uniformly dissolve or disperse the organic binder.
  • an aromatic hydrocarbon such as toluene.
  • Common organic solvents such as francs such as tetrahydrofuran, ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferably used.
  • alcohols ethylene glycol, propylene glycol, etc.
  • various propylene oxide glycol ethers such as monomethyl acetate may be appropriately added to these solvents.
  • water may be used as a solvent.
  • alcohols methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, etc.
  • the composition for forming a porous layer preferably has a solid content including fine particles having an heat resistant temperature of 150 ° C. or higher and an organic binder, for example, 10 to 80% by mass.
  • the composition for forming a porous layer is used as a base material (porous resin film, electrode, or fibrous sheet-like material) in order to increase the orientation.
  • a method of applying a share of the above composition a method of using a composition for forming a porous layer having a high solid content concentration (for example, 50 to 80% by mass); and fine particles having a heat resistant temperature of 150 ° C. or more.
  • Disperse in a solvent using various mixing / stirring devices such as dispersers, agitators, homogenizers, ball mills, attritors, jet mills, dispersing devices, etc., and a binder (and fibrous material if necessary) , Heat-meltable fine particles, swellable fine particles, etc.), and a method for using the composition for forming a porous layer prepared by adding and mixing; dispersants such as fats and oils, surfactants and silane coupling agents on the surface
  • a method for using a porous layer forming composition prepared by using fine particles having a heat-resistant temperature of 150 ° C. or higher whose surface has been modified; fine particles having a heat-resistant temperature of 150 ° C.
  • a method of pressurizing or heating and pressing the whole separator a method of applying a magnetic field before drying after applying the porous layer forming composition on a substrate;
  • the nonaqueous battery separator of the present invention (hereinafter simply referred to as “separator”) is obtained by forming the porous layer of the present invention on a porous resin film.
  • the same resin (thermoplastic resin) as the resin constituting the heat-meltable fine particles is used as the resin constituting the porous resin film.
  • the shutdown temperature of the porous resin film is desirably set in the range of 80 ° C. to 150 ° C. Therefore, it is desirable to use a thermoplastic resin having a melting point of 80 to 150 ° C.
  • a heat resistant porous resin film can be used.
  • the heat resistant temperature is 150 ° C. or more, it is stable to a non-aqueous electrolyte used in a battery, and further stable to a redox reaction inside the battery.
  • Any resin can be used. More specifically, heat-resistant resins such as polyimide, polyamideimide, aramid, polytetrafluoroethylene, polysulfone, polyurethane, PAN, polyester (PET, PBT, PEN, etc.) can be mentioned.
  • the porous resin film includes, for example, a porous film composed of the above-described exemplary resins used in conventionally known non-aqueous batteries, that is, ions produced by a solvent extraction method, a dry or wet stretching method, and the like.
  • a permeable porous film can be used.
  • a film microporous by a foaming method using a drug, supercritical CO 2 or the like can also be used.
  • the separator of the present invention because of the action of the porous layer of the present invention, it is possible to ensure good heat resistance (heat shrinkage resistance) even when a porous resin film that is easily heat-shrinkable is applied. It is preferable to employ a porous resin film that can ensure a good shutdown function, and it is more preferable to use a porous film (microporous film) made of polyolefin (PE, PP, ethylene-propylene copolymer, etc.).
  • PE polyolefin
  • the porous layer and the porous resin film do not need to be one each, and one or both may be two or more layers, but the number of layers of the separator is excessively increased.
  • the total number of layers of the porous layer and the porous resin film is preferably 5 or less.
  • the thickness of the separator of the present invention is preferably 3 ⁇ m or more, for example. More preferably, it is 5 ⁇ m or more.
  • the thickness of the separator is preferably 50 ⁇ m or less, and more preferably 30 ⁇ m or less.
  • the thickness of the porous layer is X ( ⁇ m) and the thickness of the porous resin film is Y ( ⁇ m)
  • the ratio Y / X between X and Y is 1 to 20, and the thickness of the entire separator is It is preferable to satisfy a suitable value. If Y / X is too large, the porous layer becomes too thin. For example, when the dimensional stability of the porous resin film at high temperatures is poor, the effect of suppressing the thermal shrinkage may be reduced. On the other hand, if Y / X is too small, the porous layer becomes too thick, increasing the thickness of the entire separator, and possibly causing deterioration of battery characteristics such as load characteristics.
  • the thickness X is the total thickness
  • the thickness Y is the total thickness.
  • the thickness of the porous resin film (when the separator has a plurality of porous resin films, the total thickness) is expressed by a specific value, it is preferably 5 ⁇ m or more, and 30 ⁇ m or less. It is preferable.
  • the thickness of the porous layer in the separator when the separator has a plurality of porous layers, it is preferable that the total thickness satisfies the preferred thickness of the porous layer described above.
  • the separator of the present invention preferably has a thermal shrinkage rate at 150 ° C. of 5% or less in the nonaqueous electrolytic solution (the solvent) measured by the method described in the examples.
  • the porosity of the separator is preferably 20% or more, and preferably 30% or more in a dried state, in order to ensure the amount of the nonaqueous electrolyte retained and to improve the ion permeability. It is more preferable.
  • the porosity of the separator is preferably 70% or less, more preferably 60% or less, in a dry state. Note that the porosity of the separator: P (%) is obtained by setting m as the mass per unit area of the separator (g / cm 2 ) and t as the thickness of the separator (cm) in the above formula (3). , Can be obtained using the above equation (3).
  • m is the mass per unit area (g / cm ⁇ 2 >) of a porous resin film
  • t is the thickness (cm) of a porous resin film
  • the said Formula (3) Can also be used to determine the porosity of the porous resin film: P (%).
  • the porosity of the porous resin film obtained by this method is preferably 30 to 70%.
  • the strength of the separator is desirably 50 g or more in terms of piercing strength using a needle having a diameter of 1 mm. If the piercing strength is too low, a short circuit may occur due to the piercing of the separator when lithium dendrite crystals are generated.
  • the air permeability of the separator is measured by a method in accordance with JIS P 8117, and is a Gurley value indicated by the number of seconds that 100 ml of air passes through the membrane under a pressure of 0.879 g / mm 2 , and is 10 to 300 sec. It is desirable to be. If the air permeability is too high, the ion permeability is reduced, and if it is too low, the strength of the separator may be reduced.
  • Gs Gurley value of the separator
  • Ga Gurley value of the porous resin film
  • Gb Gurley value of the porous layer of the present invention
  • the puncture strength and air permeability described above can be ensured by using a separator having the structure described above.
  • the 180 ° peel strength between the porous layer and the porous resin film is preferably 0.6 N / cm or more, and more preferably 1.0 N / cm or more.
  • the peel strength here is a value measured by the following method. An adhesive tape is attached to a 2 cm ⁇ 2 cm region on the surface of the porous layer on a test piece cut out in a size of 5 cm ⁇ 2 cm from the separator. The adhesive tape has a width of 2 cm and a length of about 5 cm, and is attached so that one end of the adhesive tape and one end of the porous layer are aligned.
  • the end of the test piece on the opposite side of the adhesive tape and the end of the adhesive tape attached to the test piece on the opposite side of the test piece Gripping and pulling at a pulling speed of 10 mm / min to measure the strength when the porous layer is peeled off.
  • the porous layer (the porous layer of the present invention) is represented by the general formula (1) and the N-vinylcarboxylic amide represented by the general formula (1), which is excellent in adhesiveness. Since a copolymer with an unsaturated carboxylic acid monomer that satisfies the copolymerization ratio is used as the organic binder, the peel strength between the porous layer and the porous resin film is Can be raised like.
  • the nonaqueous battery electrode of the present invention (hereinafter simply referred to as “electrode”) is obtained by forming the porous layer of the present invention on an electrode mixture layer (positive electrode mixture layer or negative electrode mixture layer).
  • the electrode of the present invention is used for a positive electrode or a negative electrode of a nonaqueous battery.
  • a battery in which the electrode of the present invention is used there are a non-aqueous primary battery and a non-aqueous secondary battery.
  • the main non-aqueous secondary battery is used as a battery in which the electrode of the present invention is used. Details of the electrode having a configuration suitable for the above will be described.
  • an electrode of the present invention when used for a positive electrode of a nonaqueous battery, for example, an electrode mixture layer (positive electrode mixture layer) containing a positive electrode active material, a conductive additive, a binder, and the like is used.
  • an electrode mixture layer positive electrode mixture layer
  • a structure having a structure in which the porous layer of the present invention is formed on both electrode mixture layers on both surfaces is exemplified.
  • the positive electrode active material examples include lithium cobalt oxides such as LiCoO 2 ; lithium manganese oxides such as LiMnO 2 and Li 2 MnO 3 ; lithium nickel oxides such as LiNiO 2 ; LiMn 2 O 4 and Li 4/3 Ti 5/3 O 4 and other spinel-structured lithium-containing composite oxides; LiFePO 4 and other olivine-structured lithium-containing composite oxides; oxides obtained by substituting the above-mentioned oxides with various elements; Only one of these may be used, or two or more may be used in combination.
  • lithium cobalt oxides such as LiCoO 2
  • lithium manganese oxides such as LiMnO 2 and Li 2 MnO 3
  • lithium nickel oxides such as LiNiO 2
  • LiMn 2 O 4 and Li 4/3 Ti 5/3 O 4 and other spinel-structured lithium-containing composite oxides LiFePO 4 and other olivine-structured lithium-containing composite oxides
  • Examples of the conductive auxiliary agent related to the positive electrode mixture layer include graphites such as natural graphite (flaky graphite, etc.) and artificial graphite; acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc. It is preferable to use carbon materials such as carbon blacks; carbon fibers; and conductive fibers such as metal fibers; carbon fluorides; metal powders such as aluminum; zinc oxide; and conductive materials such as potassium titanate. Conductive whiskers; conductive metal oxides such as titanium oxide; organic conductive materials such as polyphenylene derivatives; and the like can also be used.
  • binder related to the positive electrode mixture layer examples include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), and the like.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • SBR styrene butadiene rubber
  • CMC carboxymethyl cellulose
  • PVP polyvinyl pyrrolidone
  • a positive electrode mixture containing a positive electrode active material, a conductive additive, a binder, and the like is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) or water to form a paste-like or slurry-like positive electrode mixture.
  • NMP N-methyl-2-pyrrolidone
  • An agent-containing composition is prepared (however, the binder may be dissolved in a solvent), applied to one or both sides of the current collector, dried, and then subjected to a calender treatment as necessary.
  • the positive electrode as a base material, it can be produced through the step of forming the porous layer of the present invention on the positive electrode mixture layer by the method described above.
  • the positive electrode is not limited to those manufactured by the above method, and may be manufactured by other methods.
  • the positive electrode current collector aluminum foil, punching metal, net, expanded metal, or the like can be used, but aluminum foil is usually used.
  • the thickness of the positive electrode current collector is preferably 10 to 30 ⁇ m.
  • a lead body for electrical connection with other members in the non-aqueous battery may be formed on the positive electrode according to a conventional method, if necessary.
  • the content of the positive electrode active material is preferably 80.0 to 99.8% by mass, and the content of the conductive auxiliary agent is 0.1 to 10% by mass.
  • the binder content is preferably 0.1 to 10% by mass.
  • the thickness of the positive electrode mixture layer is preferably 1 to 100 ⁇ m per side of the current collector.
  • an electrode of the present invention when used for a negative electrode of a nonaqueous battery, for example, an electrode mixture layer (a negative electrode mixture layer) containing a negative electrode active material and a binder, and further, if necessary, a conductive additive, etc. And a structure in which the porous layer of the present invention is formed on one or both surfaces of the current collector and on the electrode mixture layer.
  • the negative electrode active material may be any material that can be doped / undoped with lithium ions.
  • lithium or a lithium-containing compound can also be used as the negative electrode active material.
  • the lithium-containing compound include tin oxide, silicon oxide, nickel-silicon alloy, magnesium-silicon alloy, tungsten oxide, lithium iron composite oxide, lithium-aluminum, and lithium-lead.
  • lithium alloys such as lithium-indium, lithium-gallium, and lithium-indium-gallium.
  • the same binders as those exemplified above as the binder relating to the positive electrode mixture layer can be used.
  • the negative electrode mixture layer contains a conductive additive
  • the same conductive assistants as those exemplified above as the conductive additive related to the positive electrode mixture layer can be used.
  • the negative electrode includes, for example, a negative electrode active material, a binder, and, if necessary, a negative electrode mixture containing a conductive auxiliary agent in a solvent such as NMP or water to disperse a paste or slurry-like positive electrode mixture.
  • a solvent such as NMP or water
  • the binder may be dissolved in a solvent.
  • This is applied to one or both sides of the current collector, dried, and then calendered as necessary.
  • the negative electrode is not limited to those manufactured by the above method, and may be manufactured by other methods.
  • a foil made of copper, stainless steel, nickel, titanium, or an alloy thereof, a punched metal, an expanded metal, a net, or the like can be used.
  • a copper having a thickness of 5 to 30 ⁇ m is used.
  • a foil is preferably used.
  • a lead body for electrical connection with other members in the nonaqueous battery may be formed on the negative electrode according to a conventional method, if necessary.
  • the content of the negative electrode active material is preferably 70 to 99% by mass, and the content of the binder is preferably 1 to 30% by mass.
  • the content of the conductive assistant in the negative electrode mixture layer is preferably 1 to 20% by mass.
  • the thickness of the negative electrode mixture layer is preferably 1 to 100 ⁇ m per side of the current collector.
  • the nonaqueous battery of the present invention has a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte
  • the separator is the separator of the present invention, or has a positive electrode, a negative electrode, and a nonaqueous electrolyte, and the positive electrode and the negative electrode
  • at least one of the electrodes is the electrode of the present invention, and there are no particular restrictions on the other configurations and structures, and various configurations employed in conventionally known non-aqueous batteries such as lithium secondary batteries And structure can be applied.
  • the porous layer (the porous layer of the present invention) according to the electrode of the present invention plays the role of a separator, but a separate separator is used.
  • the porous resin film for constituting the separator can be used as the separator in that case.
  • the positive electrode when the electrode of the present invention is not used as a positive electrode, the positive electrode has the same configuration as the electrode of the present invention except that it has the porous layer of the present invention. Can be used.
  • the negative electrode having the same configuration as that of the electrode of the present invention is used except that the positive electrode has the porous layer of the present invention. Can be used.
  • the positive electrode and the negative electrode are laminated with a separator interposed therebetween, or are laminated so that a porous layer formed on at least one electrode mixture layer is interposed therebetween. It is used in the form of a laminated body (laminated electrode body) or a wound body (wound electrode body) obtained by winding this laminated body in a spiral shape.
  • non-aqueous electrolyte of the non-aqueous battery As the non-aqueous electrolyte of the non-aqueous battery, as described above, a solution (non-aqueous electrolyte) in which a lithium salt is dissolved in an organic solvent is used.
  • the lithium salt is not particularly limited as long as it dissociates in a solvent to form Li + ions and does not cause a side reaction such as decomposition in a voltage range used as a battery.
  • inorganic lithium salts such as LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 ; LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ⁇ 2), LiN (R f OSO 2 ) 2 [where R f is a fluoroalkyl group], etc .; Can be used.
  • inorganic lithium salts such as LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 ; LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ⁇ 2),
  • the organic solvent used in the non-aqueous electrolyte is not particularly limited as long as it dissolves the lithium salt and does not cause side reactions such as decomposition in the voltage range used as a battery.
  • cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate
  • chain carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate
  • chain esters such as methyl propionate
  • cyclic esters such as ⁇ -butyrolactone
  • Chain ethers such as ethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme and tetraglyme
  • cyclic ethers such as dioxane, tetrahydrofuran and 2-methyltetrahydrofuran
  • nitriles such as acetonitrile, propionitrile and methoxypropionitrile
  • Sulfites such as
  • ⁇ may be used in combination of two or more thereof.
  • a combination that can obtain high conductivity such as a mixed solvent of ethylene carbonate and chain carbonate.
  • vinylene carbonates, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl, and fluorobenzene are used for the purpose of improving the safety, charge / discharge cycleability, and high-temperature storage properties of these non-aqueous electrolytes.
  • Additives such as t-butylbenzene can also be added as appropriate.
  • the concentration of this lithium salt in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / l, more preferably 0.9 to 1.25 mol / l.
  • melting at room temperature such as ethyl-methylimidazolium trifluoromethylsulfonium imide, heptyl-trimethylammonium trifluoromethylsulfonium imide, pyridinium trifluoromethylsulfonium imide, guanidinium trifluoromethylsulfonium imide A salt can also be used.
  • a polymer material that contains the non-aqueous electrolyte and gels may be added to make the non-aqueous electrolyte into a gel (gel electrolyte) for use in a battery.
  • Polymer materials for making non-aqueous electrolyte into gel include PVDF, vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), PAN, polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer
  • a known host polymer capable of forming a gel electrolyte such as a crosslinked polymer having an ethylene oxide chain in the main chain or side chain, and a crosslinked poly (meth) acrylate.
  • non-aqueous battery of the present invention examples include a cylindrical shape (such as a rectangular tube shape or a cylindrical shape) using a steel can or an aluminum can as an outer can. Moreover, it can also be set as the soft package battery which used the laminated film which vapor-deposited the metal as an exterior body.
  • Example 1 ⁇ Preparation of positive electrode> LiCoO 2 as a positive electrode active material: 90 parts by mass, carbon black as a conductive auxiliary agent: 5 parts by mass are added and mixed, and a solution in which 5 parts by mass of PVDF as a binder is dissolved in NMP is added to this mixture.
  • the mixture was mixed to obtain a positive electrode mixture-containing slurry, which was passed through a 70-mesh net to remove a large particle size.
  • This positive electrode mixture-containing slurry is uniformly applied to both sides of a positive electrode current collector made of an aluminum foil having a thickness of 15 ⁇ m, dried, and then compression-molded by a roll press machine to a total thickness of 105 ⁇ m, followed by cutting. Then, an aluminum lead body was welded to the exposed portion of the current collector to produce a strip-like positive electrode.
  • Boehmite powder (plate shape, average particle size: 1 ⁇ m, aspect ratio: 10, specific surface area: 8 m 2 / g): 4000 g, fine particles having a heat-resistant temperature of 150 ° C. or higher, are added to water: 4000 g in four portions, A uniform slurry was prepared by stirring at 2800 rpm for 5 hours with a disper. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio 90:10, molecular weight: 500,000). Further, water was added and the mixture was stirred at room temperature until uniformly dispersed to prepare a slurry for forming a porous layer having a solid content concentration of 30% by mass.
  • the slurry for forming a porous layer is applied by a microgravure coater on a treated surface of a PE microporous membrane (thickness: 16 ⁇ m, porosity: 40%, PE melting point: 135 ° C.) subjected to corona discharge treatment on one side. And drying to form a porous layer, thereby obtaining a separator having a thickness of 20 ⁇ m.
  • a microgravure coater on a treated surface of a PE microporous membrane (thickness: 16 ⁇ m, porosity: 40%, PE melting point: 135 ° C.) subjected to corona discharge treatment on one side. And drying to form a porous layer, thereby obtaining a separator having a thickness of 20 ⁇ m.
  • ⁇ Battery assembly> The separator obtained as described above was laminated while being interposed between the positive electrode and the negative electrode so that the porous layer was directed to the positive electrode side, and wound into a spiral shape to produce a wound electrode body.
  • the obtained wound electrode body is put into an iron outer can (battery case) having a diameter of 18 mm and a height of 65 mm, and after sealing with a nonaqueous electrolyte, sealing is performed, and the nonaqueous water having the structure shown in FIG. A secondary battery was produced.
  • the battery shown in FIG. 1 will be described.
  • the positive electrode 1 and the negative electrode 2 are spirally wound via the separator 3, and nonaqueous electrolysis is used as a wound electrode body. It is accommodated in the battery case 5 together with the liquid 4.
  • the current collectors used for manufacturing the positive electrode 1 and the negative electrode 2 are not shown, and each layer of the separator is not shown.
  • the battery case 5 is made of stainless steel, and an insulator 6 made of PP is disposed at the bottom of the battery case 5 prior to insertion of the wound electrode body.
  • the sealing plate 7 is made of aluminum and has a disk shape.
  • a thin portion 7a is provided at the center of the sealing plate 7, and a pressure introduction port 7b for allowing the battery internal pressure to act on the explosion-proof valve 9 around the thin portion 7a.
  • the protrusion part 9a of the explosion-proof valve 9 is welded to the upper surface of this thin part 7a, and the welding part 11 is comprised.
  • the thin-walled portion 7a provided on the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 are shown only on the cut surface for easy understanding on the drawing, and the contour behind the cut surface is The illustration is omitted.
  • the welded portion 11 of the thin-walled portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 is also illustrated in an exaggerated state so as to facilitate understanding on the drawing.
  • the terminal plate 8 is made of rolled steel, has a nickel plating on the surface, and has a cap shape with a peripheral edge portion, and the terminal plate 8 is provided with a gas discharge port 8a.
  • the explosion-proof valve 9 is made of aluminum and has a disk shape, and a central portion is provided with a protruding portion 9a having a tip portion on the power generation element side (lower side in FIG. 1) and a thin portion 9b. As described above, the lower surface of the protruding portion 9a is welded to the upper surface of the thin portion 7a of the sealing plate 7 to constitute the welded portion 11.
  • the insulating packing 10 is made of PP and has an annular shape. The insulating packing 10 is arranged at the upper part of the peripheral edge of the sealing plate 7.
  • the explosion-proof valve 9 is arranged at the upper part of the insulating packing 10 and insulates the sealing plate 7 and the explosion-proof valve 9.
  • the gap between the two is sealed so that the non-aqueous electrolyte does not leak between the two.
  • the annular gasket 12 is made of PP
  • the lead body 13 is made of aluminum
  • the sealing plate 7 and the positive electrode 1 are connected
  • an insulator 14 is disposed on the upper part of the wound electrode body
  • the negative electrode 2 and the battery case 5 The bottom is connected by a lead body 15 made of nickel.
  • the thin-walled portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 are in contact with each other at the welded portion 11, and the peripheral portion of the explosion-proof valve 9 and the peripheral portion of the terminal plate 8 are in contact. Since the positive electrode 1 and the sealing plate 7 are connected by the lead body 13 on the positive electrode side, in the normal state, the positive electrode 1 and the terminal plate 8 are connected to the lead body 13, the sealing plate 7, the explosion-proof valve 9 and their welding.
  • the portion 11 provides an electrical connection and functions normally as an electrical circuit.
  • the non-aqueous secondary battery of this example has a design electric capacity of 1400 mAh when charged to 4.2 V (the positive electrode potential is 4.3 V with respect to Li) (for all examples and comparative examples described later). The same applies to the battery).
  • Example 2 The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide, an organic binder, and sodium acrylate (copolymerization ratio 70:30 by mass ratio, molecular weight: 500,000). Further, water was added and the mixture was stirred at room temperature until it was uniformly dispersed to obtain a slurry having a solid content concentration of 30% by mass. To this slurry, a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass of water, and stirred until uniform to prepare a slurry for forming a porous layer.
  • a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass
  • a slurry having a thickness of 20 ⁇ m was obtained by applying the slurry for forming a porous layer using a gravure coater on the same microporous membrane made of PE as that used for producing the separator in Example 1, and then drying the slurry. .
  • the non-aqueous secondary battery was produced like Example 1 except having used the said separator.
  • Example 3 The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio 90:10 by mass ratio, molecular weight: 1 million). Further, water was added and the mixture was stirred at room temperature until it was uniformly dispersed to obtain a slurry having a solid content concentration of 30% by mass. To this slurry, a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass of water, and stirred until uniform to prepare a slurry for forming a porous layer.
  • a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass of
  • a separator having a thickness of 20 ⁇ m was prepared in the same manner as in Example 2 except that the slurry for forming the porous layer was used, and a nonaqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used. did.
  • Example 4 instead of the PE microporous membrane, a microporous membrane in which three layers of PP layer and PE layer are laminated in the order of PP / PE / PP (thickness: 16 ⁇ m, porosity: 45%, thickness of each layer; PP layer: A separator was prepared in the same manner as in Example 3 except that 5 ⁇ m / PE layer: 6 ⁇ m / PP layer: 5 ⁇ m) was used. And the non-aqueous secondary battery was produced like Example 1 except having used this separator.
  • Example 5 The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry.
  • 4000 g of an aqueous dispersion (solid content concentration: 40% by mass) of PE fine particles (PE melting point: 135 ° C.), which are hot-melt fine particles, N-vinylacetamide, which is an organic binder, and sodium acrylate 2100 g of an aqueous solution (copolymerization ratio is 90:10 by weight ratio, molecular weight: 500,000): 2100 g, and water is added so that the solid content concentration is 30% by mass.
  • the mixture was stirred until it became uniform to obtain a slurry for forming a porous layer.
  • porous layer forming slurry was dip coated on a PET nonwoven fabric (weighing 8 g / m 2 , thickness 16 ⁇ m) to prepare a porous film (porous layer) having a thickness of 20 ⁇ m.
  • a nonaqueous secondary battery was produced in the same manner as in Example 1 except that this porous membrane was used as a separator.
  • Example 6 Alumina fine particles (average particle size: 0.4 ⁇ m, specific surface area: 7 m 2 / g) are used as fillers, and 4000 g of alumina powder is added to 4000 g of water in four portions, and stirred with a disper at 2800 rpm for 5 hours to form a uniform slurry.
  • alumina fine particles average particle size: 0.4 ⁇ m, specific surface area: 7 m 2 / g
  • an aqueous dispersion (solid content concentration: 40% by mass) of PE fine particles (PE melting point: 135 ° C.) as heat-melting fine particles: 4000 g, an organic binder N-vinylacetamide, and an acrylic acid Na salt
  • a copolymer (copolymerization ratio is 90:10 by mass ratio, molecular weight: 500,000) and a 5 mass% aqueous solution: 1600 g is added, and water is further added so that the solid content concentration becomes 30 mass%.
  • the mixture was stirred until it became uniform to prepare a slurry for forming a porous layer.
  • the slurry for forming the porous layer is applied on the negative electrode mixture layer on both sides of the same negative electrode as that prepared in Example 1 using a gravure coater and dried, and a porous material having a thickness of 20 ⁇ m on one side of the negative electrode. A quality layer was formed.
  • a wound electrode body was prepared in the same manner as in Example 1 except that the same positive electrode as that prepared in Example 1 and the above-described negative electrode were used and a separator was not used, and this wound electrode body was used.
  • a nonaqueous secondary battery was produced in the same manner as Example 1 except for the above.
  • Example 7 The same slurry for forming a porous layer as that prepared in Example 6 was applied on the negative electrode mixture layer on both sides of the same negative electrode as that prepared in Example 1 using a gravure coater and dried. A porous layer having a thickness of 10 ⁇ m was formed. Also, the same slurry for forming a porous layer as that prepared in Example 6 was applied on the positive electrode mixture layer on both sides of the same positive electrode as that prepared in Example 1 using a gravure coater and dried. A porous layer having a thickness of 10 ⁇ m per side was formed.
  • a wound electrode body was prepared in the same manner as in Example 6 except that the negative electrode and the positive electrode were used, and a non-aqueous secondary battery was performed in the same manner as in Example 1 except that this wound electrode body was used. Was made.
  • Comparative Example 1 The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1200 g of a 5 mass% aqueous solution of poly N-vinylacetamide (a homopolymer of N-vinylacetamide, molecular weight 1 million) as an organic binder, and water was added until room temperature until evenly dispersed. And a slurry for forming a porous layer having a solid content concentration of 30% by mass was prepared. A separator was prepared in the same manner as in Example 1 except that this porous layer forming slurry was used, and a non-aqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used.
  • poly N-vinylacetamide a homopolymer of N-vinylacetamide, molecular weight 1 million
  • Comparative Example 2 The same boehmite particles: 4000 g as used in Comparative Example 1 were added to water: 4000 g in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry, 1200 g of a 5% by weight aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio is 40:60, molecular weight: 500,000) is added. The mixture was stirred at room temperature until it was uniformly dispersed to prepare a slurry for forming a porous layer. A separator was prepared in the same manner as in Example 1 except that this porous layer forming slurry was used, and a non-aqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used.
  • the 180 ° peel strength between the porous layer and the porous resin film was measured by the method described above.
  • separators used in the non-aqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2 porous membranes (porous layers) used as separators in the non-aqueous secondary battery of Example 5, and Examples About the porous layer used for the non-aqueous secondary battery of 6 and 7, the thermal contraction rate measurement in a non-aqueous electrolyte solvent was performed.
  • sample pieces are taken out from the pressure and heat resistant container, and the lengths in the MD direction and the TD direction are measured to measure the heat shrinkage rates in the respective directions, and the heat shrinkage rates in the MD direction and the heat shrinkage in the TD direction. The larger value of the rates was taken as the thermal shrinkage rate of the separator.
  • the porous membrane according to the non-aqueous secondary battery of Example 5 is the same as the separator according to the battery of Example 1 except that a strip-shaped sample piece having a size of 5 cm ⁇ 10 cm in any direction was produced.
  • the heat shrinkage rate was measured by the method.
  • the porous layer according to the non-aqueous secondary battery of Examples 6 and 7 is related to the battery of Example 1 except that a strip-shaped sample piece of 5 cm ⁇ 10 cm is produced in an integrated state with the electrode.
  • the thermal shrinkage rate was measured by the same method as for a separator.
  • the larger one of what was formed in the positive electrode surface and what was formed in the negative electrode surface was made into the thermal contraction rate.
  • the moisture content of the separators according to the non-aqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2 and the porous membrane according to the non-aqueous secondary battery of Example 5 was measured by the above method.
  • Table 1 shows the evaluation results.
  • the 180 ° peel strength between the porous layer and the porous resin film in the separator is simply referred to as “peel strength”, and the heat in the nonaqueous electrolyte solvent of the separator or porous layer is described.
  • the shrinkage rate is simply referred to as “thermal shrinkage rate”.
  • the separators or porous layers used in the nonaqueous secondary batteries of Examples 1 to 7 had a small heat shrinkage rate at 150 ° C. in a nonaqueous electrolyte solvent. That is, since these separators and porous layers are unlikely to shrink even when exposed to high temperatures in the presence of a non-aqueous electrolyte solvent in the battery, it is possible to constitute a non-aqueous secondary battery with excellent safety. I can say that. From the measurement results of the 180 ° peel strength between the porous layer and the porous resin film in the separators according to the nonaqueous secondary batteries of Examples 1 to 4, the nonaqueous secondary batteries of Examples 1 to 7 were used.
  • the organic binder used in the separator or porous layer used in the above has a specific copolymer composition, and thus has a high adhesive force.
  • the excellent adhesive force can be maintained well.
  • charge / discharge characteristics of the non-aqueous secondary batteries of Examples and Comparative Examples were evaluated by the following method.
  • constant current charging was performed until the battery voltage reached 4.2 V at a current value of 0.2 C, and then constant current-constant voltage charging for performing constant voltage charging at 4.2 V was performed.
  • the total charging time until the end of charging was 15 hours.
  • the charge capacity at that time was measured.
  • each battery after charging was discharged at a discharge current of 0.2 C until the battery voltage reached 3.0 V, and the discharge capacity was measured.
  • the ratio of the discharge capacity with respect to charge capacity was represented by the percentage, and charging efficiency was calculated
  • the nonaqueous battery of the present invention can be applied to the same uses as conventionally known nonaqueous secondary batteries such as lithium secondary batteries and nonaqueous primary batteries.

Abstract

Provided are: a highly safe nonaqueous battery; and a porous layer, a separator and an electrode for constituting the nonaqueous battery. A porous layer for nonaqueous batteries according to the present invention contains fine particles having an upper temperature limit of 150°C or more and a copolymer of an N-vinyl carboxylic acid amide of a specific structure and an unsaturated carboxylic acid monomer of a specific structure, said copolymer serving as an organic binder. The copolymerization ratio of the N-vinyl carboxylic acid amide to the unsaturated carboxylic acid monomer in the copolymer is from 50:50 to 95:5 in terms of mass ratio. A separator for nonaqueous batteries according to the present invention is obtained by forming this porous layer on a porous resin film. An electrode for nonaqueous batteries according to the present invention is obtained by forming this porous layer on an electrode mixture layer. A nonaqueous battery according to the present invention is obtained by employing this separator as the separator thereof, or by employing this electrode as the positive electrode and/or the negative electrode thereof.

Description

非水電池用多孔質層、非水電池用セパレータ、非水電池用電極および非水電池Nonaqueous battery porous layer, nonaqueous battery separator, nonaqueous battery electrode and nonaqueous battery
　本発明は、高い安全性を有する非水電池と、前記非水電池を構成するための多孔質層、セパレータおよび電極とに関するものである。 The present invention relates to a non-aqueous battery having high safety and a porous layer, a separator and an electrode for constituting the non-aqueous battery.
　非水電池の一種であるリチウム二次電池は、エネルギー密度が高いという特徴から、携帯電話やノート型パーソナルコンピューターなどの携帯機器の電源として広く用いられている。そして、携帯機器の高性能化に伴ってリチウム二次電池の高容量化が更に進む傾向にあり、安全性の確保が重要となっている。 A lithium secondary battery, which is a type of non-aqueous battery, is widely used as a power source for portable devices such as mobile phones and notebook personal computers because of its high energy density. As the performance of portable devices increases, the capacity of lithium secondary batteries tends to increase further, and it is important to ensure safety.
　現行のリチウム二次電池では、正極と負極の間に介在させるセパレータとして、例えば厚みが１５～３０μｍ程度のポリオレフィン系の多孔性フィルムが使用されている。また、セパレータの素材としては、電池の熱暴走温度以下でセパレータの構成樹脂を溶融させて空孔を閉塞させ、これにより電池の内部抵抗を上昇させて短絡の際などに電池の安全性を向上させる所謂シャットダウン効果を確保するため、融点の低いポリエチレンが適用されることがある。 In current lithium secondary batteries, a polyolefin-based porous film having a thickness of, for example, about 15 to 30 μm is used as a separator interposed between a positive electrode and a negative electrode. In addition, as separator material, the constituent resin of the separator is melted below the thermal runaway temperature of the battery to close the pores, thereby increasing the internal resistance of the battery and improving the safety of the battery in the event of a short circuit. In order to ensure the so-called shutdown effect, polyethylene having a low melting point may be applied.
　ところで、こうしたセパレータとしては、例えば、多孔化と強度向上のために一軸延伸または二軸延伸したフィルムが用いられている。このようなセパレータは、単独で存在する膜として供給されるため、作業性などの点で一定の強度が要求され、これを前記延伸によって確保している。しかし、このような延伸フィルムでは結晶化度が増大しており、シャットダウン温度も、電池の熱暴走温度に近い温度にまで高まっているため、電池の安全性確保のためのマージンが十分とは言い難い。 By the way, as such a separator, for example, a uniaxially stretched film or a biaxially stretched film is used for increasing the porosity and improving the strength. Since such a separator is supplied as a single film, a certain strength is required in terms of workability and the like, and this is secured by the stretching. However, with such a stretched film, the degree of crystallinity has increased, and the shutdown temperature has increased to a temperature close to the thermal runaway temperature of the battery. Therefore, it can be said that the margin for ensuring the safety of the battery is sufficient. hard.
　また、前記延伸によってフィルムにはひずみが生じており、これが高温に曝されると、残留応力によって収縮が起こるという問題がある。収縮温度は、シャットダウン温度と非常に近いところに存在する。このため、ポリオレフィン系の多孔性フィルムセパレータを使用するときには、充電異常時などに電池の温度がシャットダウン温度に達すると、電流を直ちに減少させて電池の温度上昇を防止しなければならない。空孔が十分に閉塞せず電流を直ちに減少できなかった場合には、電池の温度は容易にセパレータの収縮温度にまで上昇するため、内部短絡による発火の危険性があるからである。 In addition, the film is distorted by the stretching, and when it is exposed to high temperature, there is a problem that shrinkage occurs due to residual stress. The shrinkage temperature is very close to the shutdown temperature. For this reason, when a polyolefin-based porous film separator is used, when the battery temperature reaches the shutdown temperature in the case of abnormal charging, the current must be immediately decreased to prevent the battery temperature from rising. This is because if the pores are not sufficiently closed and the current cannot be reduced immediately, the battery temperature easily rises to the contraction temperature of the separator, and there is a risk of ignition due to an internal short circuit.
　このようなセパレータの熱収縮による短絡を防止し、電池の信頼性を高める技術として、例えば特許文献１および２には、熱可塑性樹脂を含む樹脂多孔質膜の表面に、耐熱性を高めるための耐熱多孔質層を形成したセパレータを用いることが提案されている。 As a technique for preventing such a short circuit due to thermal contraction of the separator and improving the reliability of the battery, for example, Patent Documents 1 and 2 include a technique for improving heat resistance on the surface of a porous resin film containing a thermoplastic resin. It has been proposed to use a separator having a heat-resistant porous layer.
　特許文献１および２に開示の技術によれば、異常過熱した際にも熱暴走が生じ難く、安全性および信頼性に優れた非水電解液電池を提供することができる。 According to the techniques disclosed in Patent Documents 1 and 2, it is possible to provide a nonaqueous electrolyte battery that is less likely to cause thermal runaway even when abnormally overheated, and that is excellent in safety and reliability.
　また、特許文献３には、耐熱多孔質層において、その主成分である耐熱性微粒子を結着するためのバインダとして、特定量のＮ－ビニルアセトアミドの重合体または水溶性セルロース誘導体と、特定量の架橋アクリル樹脂とを併用することで、特許文献１および特許文献２に記載のセパレータよりも、更に電池の信頼性を高め得たセパレータが開示されている。 Patent Document 3 discloses that a specific amount of N-vinylacetamide polymer or water-soluble cellulose derivative and a specific amount as a binder for binding the heat-resistant fine particles as the main component in the heat-resistant porous layer. The separator which can improve the reliability of the battery further compared with the separator of patent document 1 and patent document 2 by using together with the crosslinked acrylic resin of this is disclosed.
特開２００８－１２３９９６号公報JP 2008-123996 A 特開２００８－２１０７９１号公報JP 2008-210791 A 国際公開第２０１０／１０４１２７号International Publication No. 2010/104127
　ところが、Ｎ－ビニルアセトアミドの重合体は、高温環境下において非水電解液に対する耐性に関して改善の余地があることが、本発明者らの検討により明らかとなった。 However, it has been clarified by the present inventors that the polymer of N-vinylacetamide has room for improvement with respect to the resistance to the non-aqueous electrolyte in a high temperature environment.
　本発明は、前記事情に鑑みてなされたものであり、その目的は、高い安全性を有する非水電池と、前記非水電池を構成するための多孔質層、セパレータおよび電極とを提供することにある。 This invention is made | formed in view of the said situation, The objective is providing the non-aqueous battery which has high safety | security, the porous layer, separator, and electrode for comprising the said non-aqueous battery. It is in.
　前記目的を達成し得た本発明の非水電池用多孔質層は、耐熱温度が１５０℃以上の微粒子と有機バインダとを含む非水電池用多孔質層であって、前記有機バインダとして、下記一般式（１）で表されるＮ－ビニルカルボン酸アミドと下記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体を含み、前記共重合体における前記Ｎ－ビニルカルボン酸アミドと前記不飽和カルボン酸系モノマーとの共重合比が、質量比で５０：５０～９５：５であることを特徴とするものである。 The porous layer for a nonaqueous battery of the present invention that has achieved the above object is a porous layer for a nonaqueous battery containing fine particles having an allowable temperature limit of 150 ° C. or more and an organic binder, and the organic binder includes: A copolymer of an N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the following general formula (2), the N-vinylcarboxylic acid in the copolymer: The copolymerization ratio of the acid amide and the unsaturated carboxylic acid monomer is 50:50 to 95: 5 by mass ratio.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　前記一般式（１）中、Ｒ１およびＲ２は、それぞれ独立に水素原子またはメチル基を、Ｒ３は水素原子または炭素数１～５のアルキル基を表す。 In the general formula (1), R 1 and R 2 each independently represent a hydrogen atom or a methyl group, and R 3 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　前記一般式（２）中、Ｒ４は水素原子、メチル基または－ＣＯＯＭ２を、Ｒ５は水素原子、メチル基または－ＣＯＯＭ３を、Ｍ１、Ｍ２およびＭ３は、それぞれ独立に水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基または有機アミノ基を表し、ｎは０または１である。 In the general formula (2), R 4 represents a hydrogen atom, a methyl group or —COOM 2 , R 5 represents a hydrogen atom, a methyl group or —COOM 3 , and M 1 , M 2 and M 3 each independently represent hydrogen. An atom, an alkali metal, an alkaline earth metal, an ammonium group or an organic amino group is represented, and n is 0 or 1.
　また、本発明の非水電池用セパレータは、本発明の非水電池用多孔質層を、多孔質樹脂フィルム上に形成したことを特徴とするものである。 The separator for nonaqueous batteries of the present invention is characterized in that the porous layer for nonaqueous batteries of the present invention is formed on a porous resin film.
　更に、本発明の非水電池用電極は、非水電池用多孔質層を、電極合剤層上に形成したことを特徴とするものである。 Furthermore, the electrode for nonaqueous battery of the present invention is characterized in that a porous layer for nonaqueous battery is formed on an electrode mixture layer.
　また、本発明の非水電池は、（ａ）正極、負極、セパレータおよび非水電解質を有しており、前記セパレータが本発明の非水電池用セパレータであるか、または（ｂ）正極、負極および非水電解質を有しており、前記正極および前記負極のうちの少なくとも一方が本発明の非水電池用電極であることを特徴とするものである。 The nonaqueous battery of the present invention includes (a) a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte, and the separator is the nonaqueous battery separator of the present invention, or (b) a positive electrode, a negative electrode And at least one of the positive electrode and the negative electrode is a nonaqueous battery electrode of the present invention.
　なお、本明細書において、「耐熱温度が１５０℃以上」とは、少なくとも１５０℃において軟化などの変形が見られないことを意味している。 In the present specification, “heat-resistant temperature is 150 ° C. or higher” means that deformation such as softening is not observed at least at 150 ° C.
　本発明によれば、高い安全性を有する非水電池と、前記非水電池を構成するための多孔質層、セパレータおよび電極とを提供することができる。 According to the present invention, it is possible to provide a non-aqueous battery having high safety, and a porous layer, a separator, and an electrode for constituting the non-aqueous battery.
本発明の非水電池の一例を模式的に表す縦断面図である。It is a longitudinal section showing an example of the nonaqueous battery of the present invention typically.
　本発明の非水電池用多孔質層（以下、単に「多孔質層」という場合がある）は、非水電池内において正極と負極とを仕切る隔離材として使用されるものであり、耐熱温度が１５０℃以上の微粒子と有機バインダとを含有しており、前記微粒子同士が前記有機バインダによって結着している。 The porous layer for non-aqueous batteries of the present invention (hereinafter sometimes simply referred to as “porous layer”) is used as a separator for separating the positive electrode and the negative electrode in the non-aqueous battery, and has a heat resistant temperature. It contains fine particles of 150 ° C. or higher and an organic binder, and the fine particles are bound together by the organic binder.
　本発明の多孔質層は、多孔質樹脂フィルム上に形成されることで、本発明の非水電池用セパレータを構成でき、また、非水電池の電極（正極または負極）の電極合剤層上に形成されることで、本発明の非水電池用電極を構成できる。本発明の非水電池用セパレータでは、その有機バインダによって、多孔質層中の構成成分（耐熱温度が１５０℃以上の微粒子など）同士が結着していると共に、多孔質層と多孔質樹脂フィルムとが接着している。また、本発明の非水電池用電極では、その有機バインダによって、多孔質層中の構成成分（耐熱温度が１５０℃以上の微粒子など）同士が結着していると共に、多孔質層と電極の電極合剤層とが接着している。 By forming the porous layer of the present invention on the porous resin film, the separator for a non-aqueous battery of the present invention can be constituted, and on the electrode mixture layer of the electrode (positive electrode or negative electrode) of the non-aqueous battery. Thus, the nonaqueous battery electrode of the present invention can be configured. In the separator for a non-aqueous battery of the present invention, the organic binder binds the constituent components (such as fine particles having a heat resistant temperature of 150 ° C. or higher) in the porous layer, and the porous layer and the porous resin film. And are adhered. In the electrode for a non-aqueous battery of the present invention, the organic binder binds the constituent components (such as fine particles having a heat resistant temperature of 150 ° C. or higher) in the porous layer, and the porous layer and the electrode. The electrode mixture layer is adhered.
　本発明の多孔質層では、有機バインダとして、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体であって、前記Ｎ－ビニルカルボン酸アミドと前記不飽和カルボン酸系モノマーとの共重合比が、質量比で５０：５０～９５：５であるものを使用する。 In the porous layer of the present invention, as an organic binder, a copolymer of N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the general formula (2) The copolymerization ratio of the N-vinylcarboxylic amide and the unsaturated carboxylic acid monomer is 50:50 to 95: 5 by mass.
　ポリＮ－ビニルアセトアミドなどの、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドをモノマーとする重合体は、その組成によっては、通常の非水電池で採用されている非水電解液（非水電解液溶媒）中で１００℃以上の高温に曝されると、その接着性が低下することがあり、これをバインダとして使用した多孔質層では、例えば構成成分同士の結着状態を良好に維持し得ず、想定した特性（主に耐熱性）が十分に確保し得ないことがある。 A polymer having N-vinylcarboxylic acid amide represented by the general formula (1) as a monomer, such as poly N-vinylacetamide, may be used in a nonaqueous electrolysis that is employed in a normal nonaqueous battery depending on its composition. When exposed to a high temperature of 100 ° C. or higher in a liquid (non-aqueous electrolyte solvent), the adhesiveness may decrease. In a porous layer using this as a binder, for example, the binding state of components May not be maintained satisfactorily, and the assumed characteristics (mainly heat resistance) may not be sufficiently ensured.
　本発明者らは、前記一般式（１）で表されるＮ－ビニルカルボン酸アミド由来の構造部分と、前記一般式（２）で表される不飽和カルボン酸系モノマー由来の構造部分とを、特定の比率で含む共重合体であれば、ポリＮ－ビニルアセトアミドなどに比べて高温の非水電解液に対する耐性を高め得ることを見出し、この知見に基づいて、かかる共重合体を多孔質層の有機バインダとして使用することで、従来よりも更に高い安全性（１００℃以上といった高温での安全性）を非水電池に付与し得ることを見出して、本発明を完成するに至った。 The present inventors have obtained a structural part derived from the N-vinylcarboxylic acid amide represented by the general formula (1) and a structural part derived from the unsaturated carboxylic acid monomer represented by the general formula (2). It has been found that a copolymer containing a specific ratio can increase resistance to a high-temperature non-aqueous electrolyte compared to poly N-vinylacetamide and the like, and based on this finding, the copolymer is made porous. By using it as an organic binder for the layer, it was found that higher safety (safety at a high temperature such as 100 ° C. or higher) than before can be imparted to the nonaqueous battery, and the present invention has been completed.
　前記一般式（１）で表されるＮ－ビニルカルボン酸アミドとしては、例えば、Ｎ－ビニルホルムアミド、Ｎ－ビニルアセトアミド、Ｎ－メチル－Ｎ－ビニルホルムアミド、Ｎ－メチル－Ｎ－ビニルアセトアミドなどが挙げられ、共重合体の合成には、これらのうちの１種または２種以上を用いることができる。これらの中でもＮ－ビニルアセトアミドが特に好ましい。 Examples of the N-vinylcarboxylic amide represented by the general formula (1) include N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylformamide, N-methyl-N-vinylacetamide and the like. Among them, one or more of them can be used for the synthesis of the copolymer. Of these, N-vinylacetamide is particularly preferred.
　また、前記一般式（２）で表される不飽和カルボン酸系モノマーとしては、例えば、アクリル酸、メタクリル酸、アクリル酸塩（ナトリウム塩、カリウム塩などのアルカリ金属塩など）、メタクリル酸塩（ナトリウム塩、カリウム塩などアルカリ金属塩など）などが好ましく、共重合体の合成には、これらのうちの１種または２種以上を用いることができる。これらの中でも、アクリル酸のアルカリ金属塩やメタクリル酸のアルカリ金属塩が特に好ましい。 Examples of the unsaturated carboxylic acid monomer represented by the general formula (2) include acrylic acid, methacrylic acid, acrylates (alkali metal salts such as sodium salts and potassium salts), methacrylates ( Sodium salts, alkali salts such as potassium salts, etc.) are preferred, and one or more of them can be used for the synthesis of the copolymer. Among these, alkali metal salts of acrylic acid and alkali metal salts of methacrylic acid are particularly preferable.
　前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体において、その共重合組成は、前記Ｎ－ビニルカルボン酸アミドと前記不飽和カルボン酸系モノマーとの合計を１００質量％としたとき、前記不飽和カルボン酸系モノマーの割合が、５質量％以上であり、７質量％以上であることが好ましく、１０質量％以上であることが更に好ましい（すなわち、前記Ｎ－ビニルカルボン酸アミドの割合が、９５質量％以下であり、９３質量％以下であることが好ましく、９０質量％以下であることが更に好ましい）。このような共重合組成の共重合体であれば、高温の非水電解液溶媒中での耐性が向上し、その接着力が損なわれ難くなるため、高温での安全性がより優れた非水電池を構成可能な多孔質層を形成できる。 In the copolymer of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2), the copolymer composition is the above N-vinyl. When the total of the carboxylic acid amide and the unsaturated carboxylic acid monomer is 100% by mass, the ratio of the unsaturated carboxylic acid monomer is 5% by mass or more, preferably 7% by mass or more, More preferably, it is 10% by mass or more (that is, the proportion of the N-vinylcarboxylic amide is 95% by mass or less, preferably 93% by mass or less, and more preferably 90% by mass or less. preferable). With a copolymer having such a copolymer composition, resistance in a high-temperature non-aqueous electrolyte solvent is improved, and its adhesive strength is less likely to be impaired. A porous layer capable of constituting a battery can be formed.
　ただし、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体において、前記不飽和カルボン酸系モノマー由来の成分が多くなりすぎると、共重合体の吸湿性が高くなって、多孔質層を用いた非水電池の電池特性が損なわれることがあり、また、多孔質層形成用組成物（前記共重合体の他に、耐熱温度が１５０℃以上の微粒子や溶媒を含む組成物。詳しくは後述する。）の粘度が増大しすぎて塗布性が損なわれる虞もある。よって、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと、前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体において、その共重合組成は、前記Ｎ－ビニルカルボン酸アミドと前記不飽和カルボン酸系モノマーとの合計を１００質量％としたとき、前記不飽和カルボン酸系モノマーの割合が、５０質量％以下であり、３０質量％以下であることが好ましい（すなわち、前記Ｎ－ビニルカルボン酸アミドの割合が、５０質量％以上であり、７０質量％以上であることが好ましい）。 However, the copolymer of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) is derived from the unsaturated carboxylic acid monomer. If the amount of the component is too large, the hygroscopicity of the copolymer may increase, and the battery characteristics of the nonaqueous battery using the porous layer may be impaired. In addition to the polymer, a composition containing fine particles or a solvent having a heat resistant temperature of 150 ° C. or higher (details will be described later)) may increase the viscosity too much, thereby impairing the coatability. Therefore, in the copolymer of the N-vinylcarboxylic amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2), the copolymer composition is When the total of N-vinylcarboxylic acid amide and the unsaturated carboxylic acid monomer is 100% by mass, the ratio of the unsaturated carboxylic acid monomer is 50% by mass or less and 30% by mass or less. (Ie, the proportion of the N-vinylcarboxylic acid amide is 50% by mass or more, and preferably 70% by mass or more).
　前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと、前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体の分子量は、ゲルパーミエーションクロマトグラフィーを用いて測定される数平均分子量（ポリスチレン換算値）で、好ましくは３０，０００以上、より好ましくは５０，０００以上であって、好ましくは５，０００，０００以下、より好ましくは３，０００，０００以下、更に好ましくは２，０００，０００以下である。 The molecular weight of the copolymer of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) was determined using gel permeation chromatography. The number average molecular weight (polystyrene equivalent value) measured is preferably 30,000 or more, more preferably 50,000 or more, preferably 5,000,000 or less, more preferably 3,000,000 or less. More preferably, it is 2,000,000 or less.
　前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの比率を前記の範囲とした共重合体を有機バインダとして用いることにより、前記不飽和カルボン酸系モノマーの割合が多すぎる共重合体を有機バインダとした場合よりも、バインダの吸湿に伴って電池内に持ち込まれる水分量を低減することが可能となる。なお、前記有機バインダを含む本発明の非水電池用多孔質層を多孔質樹脂フィルム上に形成した本発明の非水電池用セパレータにおいては、その水分量が、セパレータ全体として１５００ｐｐｍ以下であることが好ましい。 A copolymer having a ratio of the N-vinylcarboxylic acid amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) within the above range is used as the organic binder. As a result, it is possible to reduce the amount of moisture brought into the battery as the binder absorbs moisture, compared to the case where an organic binder is used as the copolymer in which the unsaturated carboxylic acid monomer is too much. In the non-aqueous battery separator of the present invention in which the non-aqueous battery porous layer of the present invention containing the organic binder is formed on a porous resin film, the water content of the separator as a whole is 1500 ppm or less. Is preferred.
　本明細書でいうセパレータの水分量は、下記の方法によって測定することができる。測定用のセパレータのサンプルを、露点：－５０℃のグローブボックス中に１２時間以上静置した後、窒素ガスをフローした１５０℃の加熱炉に前記測定サンプルを入れ、１分間保持する。そして、フローした窒素ガスをカールフィッシャー水分計の測定セルに導入し、水分量を測定する。滴定終点までの積算値を含有水分量とする。測定は露点－５０℃のグローブボックス中で行い、前記測定値を前記サンプルの質量で割ることにより、セパレータの単位質量あたりの水分量（単位：ｐｐｍ）を算出する。 The moisture content of the separator referred to in this specification can be measured by the following method. A separator sample for measurement is allowed to stand in a glove box having a dew point of −50 ° C. for 12 hours or more, and then the measurement sample is placed in a heating furnace at 150 ° C. in which nitrogen gas is flowed and held for 1 minute. Then, the flowd nitrogen gas is introduced into the measurement cell of the Karl Fischer moisture meter, and the moisture content is measured. The integrated value up to the titration end point is taken as the moisture content. The measurement is performed in a glove box having a dew point of −50 ° C., and the water content per unit mass of the separator (unit: ppm) is calculated by dividing the measured value by the mass of the sample.
　なお、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体は、エチレン、プロピレン、ビニルアルコール、酢酸ビニル、アクリロニトリル、またはそれらの誘導体など、他のエチレン性不飽和モノマー成分を更に含むことができる。ただし、前記作用を阻害しないために、その割合は、共重合体全体の２０質量％以下とするのが望ましい。 The copolymer of the N-vinylcarboxylic amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2) is ethylene, propylene, vinyl alcohol, acetic acid. It can further include other ethylenically unsaturated monomer components such as vinyl, acrylonitrile, or derivatives thereof. However, in order not to inhibit the above action, the ratio is desirably 20% by mass or less of the entire copolymer.
　本発明の多孔質層には、有機バインダとして、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体のみを使用してもよいが、前記共重合体と共に他の有機バインダを使用してもよい。このような他の有機バインダとしては、例えば、エチレン－酢酸ビニル共重合体（ＥＶＡ、酢酸ビニル由来の構造単位が２０～３５モル％のもの）、（メタ）アクリレート重合体〔「（メタ）アクリレート」とは、アクリレートとメタクリレートとを含む意味である。〕、フッ素系ゴム、スチレンブタジエンゴム（ＳＢＲ）、ポリビニルアルコール（ＰＶＡ）、ポリビニルブチラール（ＰＶＢ）、ポリビニルピロリドン（ＰＶＰ）、ポリウレタン、ポリＮ－ビニルアセトアミド（Ｎ－ビニルアセトアミドの単独重合体）などが挙げられ、これらのうちの１種または２種以上を使用することができる。 In the porous layer of the present invention, as an organic binder, a copolymer of an N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the general formula (2) is used. Although only a combination may be used, other organic binders may be used together with the copolymer. Examples of such other organic binders include ethylene-vinyl acetate copolymers (EVA, those having a structural unit derived from vinyl acetate of 20 to 35 mol%), (meth) acrylate polymers [“(meth) acrylates”. "Means including acrylate and methacrylate. ], Fluorinated rubber, styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), polyurethane, poly N-vinylacetamide (N-vinylacetamide homopolymer), etc. And one or more of these can be used.
　なお、多孔質層における全有機バインダのうち、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体以外の他の有機バインダの含有量は、１０質量％以下であることが好ましい。 Of the total organic binder in the porous layer, a copolymer of N-vinylcarboxylic acid amide represented by the general formula (1) and an unsaturated carboxylic acid monomer represented by the general formula (2) The content of the organic binder other than is preferably 10% by mass or less.
　耐熱温度が１５０℃以上の微粒子は、本発明の多孔質層において、その主体となったり、後述する繊維状物同士の間に形成される空隙を埋めるなどして、リチウムデンドライトに起因する短絡の発生を抑制する作用を有している。耐熱温度が１５０℃以上の微粒子としては、電気絶縁性を有しており、電気化学的に安定で、更に後述する非水電解液や、多孔質層形成用組成物（溶媒を含む組成物）に用いる溶媒に安定であり、高温状態で安定な耐熱性の高いものであれば、特に制限はない。 The fine particles having a heat-resistant temperature of 150 ° C. or more are short-circuited due to lithium dendrite by becoming a main component in the porous layer of the present invention or filling voids formed between fibrous materials described later. Has the effect of suppressing the occurrence. The fine particles having a heat-resistant temperature of 150 ° C. or higher have electrical insulating properties, are electrochemically stable, and further contain a non-aqueous electrolyte and porous layer forming composition (composition containing a solvent) described later. There is no particular limitation as long as it is stable to the solvent used in the above and is stable at high temperatures and has high heat resistance.
　なお、本明細書でいう「非水電解液に対して安定」とは、非水電解液（非水電池の電解液として使用される非水電解液）中で変形および化学的組成変化の起こらないことを意味している。また、本明細書でいう「高温状態」とは、具体的には１５０℃以上の温度であり、このような温度の非水電解液中で変形および化学的組成変化の起こらない安定な粒子であればよい。更に、本明細書でいう「電気化学的に安定な」とは、電池の充放電の際に化学変化が生じないことを意味している。 As used herein, “stable to non-aqueous electrolyte” means deformation and chemical composition change in non-aqueous electrolyte (non-aqueous electrolyte used as non-aqueous battery electrolyte). It means not. The “high temperature state” in the present specification is specifically a temperature of 150 ° C. or higher, and is a stable particle that does not undergo deformation or chemical composition change in a non-aqueous electrolyte at such a temperature. I just need it. Further, “electrochemically stable” as used in the present specification means that no chemical change occurs during charging / discharging of the battery.
　このような耐熱温度が１５０℃以上の微粒子の具体例としては、例えば、酸化鉄、ＳｉＯ２、Ａｌ２Ｏ３、ＴｉＯ２、ＢａＴｉＯ３、ＺｒＯ２、ＭｇＯ、などの酸化物微粒子；窒化アルミニウム、窒化ケイ素などの窒化物微粒子；フッ化カルシウム、フッ化バリウム、硫酸バリウムなどの難溶性のイオン結晶微粒子；シリコン、ダイヤモンドなどの共有結合性結晶微粒子；タルク、モンモリロナイトなどの粘土微粒子；ベーマイト、ゼオライト、アパタイト、カオリン、ムライト、スピネル、オリビン、セリサイト、ベントナイト、ハイドロタルサイトなどの鉱物資源由来物質またはそれらの人造物；などの無機微粒子が挙げられる。また、金属微粒子；ＳｎＯ２、スズ－インジウム酸化物（ＩＴＯ）などの酸化物微粒子；カーボンブラック、グラファイトなどの炭素質微粒子；などの導電性微粒子の表面を、電気絶縁性を有する材料（例えば、前記の電気絶縁性の耐熱温度が１５０℃以上の微粒子を構成する材料など）で表面処理することで、電気絶縁性を持たせた微粒子であってもよい。 Specific examples of such fine particles having a heat resistant temperature of 150 ° C. or higher include, for example, oxide fine particles such as iron oxide, SiO 2 , Al 2 O 3 , TiO 2 , BaTiO 3 , ZrO 2 , MgO; aluminum nitride, Nitride fine particles such as silicon nitride; poorly soluble ionic crystal fine particles such as calcium fluoride, barium fluoride and barium sulfate; covalently bonded crystal fine particles such as silicon and diamond; clay fine particles such as talc and montmorillonite; boehmite, zeolite, Examples thereof include inorganic fine particles such as substances derived from mineral resources such as apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, hydrotalcite, or artificial products thereof. Further, the surface of conductive fine particles such as metal fine particles; oxide fine particles such as SnO 2 and tin-indium oxide (ITO); carbonaceous fine particles such as carbon black and graphite; Fine particles imparted with electrical insulation properties may be obtained by surface treatment with the above-mentioned materials that constitute fine particles having an electrical insulating heat-resistant temperature of 150 ° C. or higher.
　また、耐熱温度が１５０℃以上の微粒子には、有機微粒子を用いることもできる。有機微粒子の具体例としては、ポリイミド、メラミン系樹脂、フェノール系樹脂、架橋ポリメチルメタクリレート（架橋ＰＭＭＡ）、架橋ポリスチレン（架橋ＰＳ）、ポリジビニルベンゼン（ＰＤＶＢ）、ベンゾグアナミン－ホルムアルデヒド縮合物などの架橋高分子の微粒子；熱可塑性ポリイミドなどの耐熱性高分子の微粒子；が挙げられる。これらの有機微粒子を構成する有機樹脂（高分子）は、前記例示の材料の混合物、変性体、誘導体、共重合体（ランダム共重合体、交互共重合体、ブロック共重合体、グラフト共重合体）、架橋体（前記の耐熱性高分子の場合）であってもよい。 Also, organic fine particles can be used for the fine particles having a heat resistant temperature of 150 ° C. or higher. Specific examples of organic fine particles include polyimide, melamine resin, phenolic resin, crosslinked polymethyl methacrylate (crosslinked PMMA), crosslinked polystyrene (crosslinked PS), polydivinylbenzene (PDVB), benzoguanamine-formaldehyde condensate, etc. Molecular fine particles; heat-resistant polymer fine particles such as thermoplastic polyimide; The organic resin (polymer) constituting these organic fine particles is a mixture, modified body, derivative, copolymer (random copolymer, alternating copolymer, block copolymer, graft copolymer) of the materials exemplified above. ) Or a crosslinked product (in the case of the heat-resistant polymer).
　耐熱温度が１５０℃以上の微粒子には、これらを１種単独で用いてもよく、２種以上を併用してもよい。これらの中でも、ＳｉＯ２、Ａｌ２Ｏ３、ベーマイトなどの酸化物または水酸化物の微粒子が特に好ましい。 These fine particles having a heat-resistant temperature of 150 ° C. or higher may be used alone or in combination of two or more. Among these, oxide or hydroxide fine particles such as SiO 2 , Al 2 O 3 and boehmite are particularly preferable.
　耐熱温度が１５０℃以上の微粒子の形態としては、球状、粒子状、板状などいずれの形態であってもよいが、板状であることが好ましい。板状粒子としては、各種市販品が挙げられ、例えば、旭硝子エスアイテック社製「サンラブリー」（ＳｉＯ２）、石原産業社製「ＮＳＴ－Ｂ１」の粉砕品（ＴｉＯ２）、堺化学工業社製の板状硫酸バリウム「Ｈシリーズ」、「ＨＬシリーズ」、林化成社製「ミクロンホワイト」（タルク）、林化成社製「ベンゲル」（ベントナイト）、河合石灰社製「ＢＭＭ」や「ＢＭＴ」（ベーマイト）、河合石灰社製「セラシュールＢＭＴ－Ｂ」〔アルミナ（Ａｌ２Ｏ３）〕、キンセイマテック社製「セラフ」（アルミナ）、斐川鉱業社製「斐川マイカ　Ｚ－２０」（セリサイト）などが入手可能である。この他、ＳｉＯ２、Ａｌ２Ｏ３、ＺｒＯ２、ＣｅＯ２については、特開２００３－２０６４７５号公報に開示の方法により作製することができる。 The form of the fine particles having a heat resistant temperature of 150 ° C. or higher may be any form such as a spherical shape, a particle shape, or a plate shape, but a plate shape is preferable. Examples of the plate-like particles include various commercially available products. For example, “Sun Lovely” (SiO 2 ) manufactured by Asahi Glass Stech Co., Ltd., “NST-B1” pulverized product (TiO 2 ) manufactured by Ishihara Sangyo Co., Ltd., Sakai Chemical Industry Co., Ltd. Plate-like barium sulfate “H series”, “HL series”, Hayashi Kasei “micron white” (talc), Hayashi Kasei “bengel” (bentonite), Kawai lime “BMM” and “BMT” (Boehmite), “Cerasur BMT-B” [Alumina (Al 2 O 3 )] manufactured by Kawai Lime Co., Ltd., “Seraph” (Alumina) manufactured by Kinsei Matec Co., Ltd. ) Etc. are available. In addition, SiO 2 , Al 2 O 3 , ZrO 2 , and CeO 2 can be produced by the method disclosed in Japanese Patent Laid-Open No. 2003-206475.
　耐熱温度が１５０℃以上の微粒子が板状である場合には、多孔質層中において、耐熱温度が１５０℃以上の微粒子を、その平板面が多孔質層の面にほぼ平行となるように配向させることが好ましく、このような多孔質層を有するセパレータを使用することで、電池の短絡の発生をより良好に抑制できる。これは、耐熱温度が１５０℃以上の微粒子を前記のように配向させることで、耐熱温度が１５０℃以上の微粒子同士が平板面の一部で重なるように配置されるため、多孔質層の片面から他面に向かう空隙（貫通孔）が、直線ではなく曲折した形で形成される（すなわち、曲路率が大きくなる）と考えられ、これにより、リチウムデンドライトが多孔質層を貫通することを防止できることから、短絡の発生がより良好に抑制されるものと推測される。 When the fine particles having a heat resistant temperature of 150 ° C. or higher are plate-like, the fine particles having a heat resistant temperature of 150 ° C. or higher are oriented in the porous layer so that the flat plate surface is substantially parallel to the surface of the porous layer. It is preferable to use a separator having such a porous layer, and the occurrence of a short circuit of the battery can be suppressed more favorably. This is because the fine particles having a heat-resistant temperature of 150 ° C. or more are oriented as described above, and the fine particles having a heat-resistant temperature of 150 ° C. or more are arranged so as to overlap each other on a part of the flat plate surface. It is considered that the gap (through hole) from the surface to the other surface is formed in a curved shape rather than a straight line (that is, the curvature becomes large), and this allows the lithium dendrite to penetrate the porous layer. Since it can prevent, it is estimated that generation | occurrence | production of a short circuit is suppressed more favorably.
　耐熱温度が１５０℃以上の微粒子が板状の粒子である場合の形態としては、例えば、アスペクト比（板状粒子中の最大長さと板状粒子の厚みの比）が、５以上であることが好ましく、１０以上でであることがより好ましく、また、１００以下であることが好ましく、５０以下であることがより好ましい。また、粒子の平板面の長軸方向長さと短軸方向長さの比の平均値は、０．３以上、より好ましくは０．５以上であることが望ましい（１、すなわち、長軸方向長さと短軸方向長さとが同じであってもよい）。板状の耐熱温度が１５０℃以上の微粒子が、前記のようなアスペクト比や平板面の長軸方向長さと短軸方向長さの比の平均値を有する場合には、前記の短絡防止作用がより有効に発揮される。 For example, the aspect ratio (the ratio of the maximum length in the plate-like particles to the thickness of the plate-like particles) is 5 or more as the form when the fine particles having a heat-resistant temperature of 150 ° C. or higher are plate-like particles. Preferably, it is 10 or more, more preferably 100 or less, and even more preferably 50 or less. Further, the average value of the ratio of the major axis direction length to the minor axis direction length of the flat plate surface of the grains is preferably 0.3 or more, more preferably 0.5 or more (ie, the major axis length). And the length in the minor axis direction may be the same). When the fine particles having a plate-like heat-resistant temperature of 150 ° C. or higher have the aspect ratio or the average value of the ratio of the length in the long axis direction to the length in the short axis direction of the flat plate surface, the short-circuit preventing action is achieved. More effective.
　なお、耐熱温度が１５０℃以上の微粒子が板状である場合における前記の平板面の長軸方向長さと短軸方向長さの比の平均値は、例えば、走査型電子顕微鏡（ＳＥＭ）により撮影した画像を画像解析することにより求めることができる。更に耐熱温度が１５０℃以上の微粒子が板状である場合における前記のアスペクト比も、ＳＥＭにより撮影した画像を、画像解析することにより求めることができる。 In addition, the average value of the ratio of the long axis direction length to the short axis direction length of the flat plate surface when the fine particles having a heat resistant temperature of 150 ° C. or more are plate-like is taken by, for example, a scanning electron microscope (SEM) It can obtain | require by image-analyzing the done image. Further, the aspect ratio in the case where the fine particles having a heat resistant temperature of 150 ° C. or higher are plate-like can also be obtained by image analysis of an image taken by SEM.
　また、耐熱温度が１５０℃以上の微粒子は、前記例示の各種耐熱温度が１５０℃以上の微粒子を構成する材料を２種以上含有する粒子であってもよい。 Further, the fine particles having a heat resistant temperature of 150 ° C. or higher may be particles containing two or more materials constituting the fine particles having various heat resistant temperatures exemplified above of 150 ° C. or higher.
　耐熱温度が１５０℃以上の微粒子の平均粒径は、好ましくは０．０１μｍ以上、より好ましくは０．１μｍ以上であって、好ましくは１５μｍ以下、より好ましくは５μｍ以下である。 The average particle diameter of the fine particles having a heat resistant temperature of 150 ° C. or higher is preferably 0.01 μm or more, more preferably 0.1 μm or more, preferably 15 μm or less, more preferably 5 μm or less.
　本明細書でいう耐熱温度が１５０℃以上の微粒子の平均粒径は、例えば、レーザー散乱粒度分布計（例えば、ＨＯＲＩＢＡ社製「ＬＡ－９２０」）を用い、耐熱温度が１５０℃以上の微粒子を溶解したり、耐熱温度が１５０℃以上の微粒子が膨潤したりしない媒体に、耐熱温度が１５０℃以上の微粒子を分散させて測定した数平均粒子径として規定することができる。 As used herein, the average particle size of the fine particles having a heat resistant temperature of 150 ° C. or higher is determined by, for example, using a laser scattering particle size distribution meter (for example, “LA-920” manufactured by HORIBA) to It can be defined as the number average particle diameter measured by dispersing fine particles having a heat resistant temperature of 150 ° C. or higher in a medium in which the fine particles having a heat resistant temperature of 150 ° C. or higher do not swell.
また、耐熱温度が１５０℃以上の微粒子の比表面積は、１００ｍ２／ｇ以下であることが好ましく、５０ｍ２／ｇ以下であることがより好ましく、３０ｍ２／ｇ以下であることが更に好ましい。比表面積が大きすぎると、微粒子同士を結着したり、微粒子と基材や電極とを結着したりするためのバインダ量が多くなりすぎるために電池とした時の出力特性が悪くなる虞があり、また、微粒子表面に吸着する水分が多くなって、非水電池の電池特性を低下させる虞がある。一方、耐熱温度が１５０℃以上の微粒子の比表面積の好適な下限値としては、１ｍ２／ｇである。ここでいう比表面積とは、窒素ガスを用いてＢＥＴ法により測定した値である。 The specific surface area of the fine particles having a heat resistant temperature of 150 ° C. or higher is preferably 100 m 2 / g or less, more preferably 50 m 2 / g or less, and further preferably 30 m 2 / g or less. If the specific surface area is too large, the amount of the binder for binding fine particles to each other, or binding the fine particles to the substrate or electrode may be too large, and the output characteristics may be deteriorated when the battery is used. In addition, there is a possibility that the moisture adsorbed on the surface of the fine particles increases and the battery characteristics of the nonaqueous battery are deteriorated. On the other hand, a preferable lower limit value of the specific surface area of the fine particles having a heat resistant temperature of 150 ° C. or higher is 1 m 2 / g. Here, the specific surface area is a value measured by a BET method using nitrogen gas.
　本発明の多孔質層は、前記のような耐熱性の高い耐熱温度が１５０℃以上の微粒子を用いた場合、その作用によって、高温時における熱収縮を抑制して寸法安定性を高めることができる。また、このような耐熱性の高い耐熱温度が１５０℃以上の微粒子を含有する本発明の多孔質層が電極（正極または負極）と一体化している場合には、高温時における多孔質層の寸法安定性を更に高めることができる。 When the porous layer of the present invention uses fine particles having a high heat resistance temperature of 150 ° C. or higher as described above, its action can suppress thermal shrinkage at high temperatures and improve dimensional stability. . In addition, when the porous layer of the present invention containing fine particles having a high heat resistance of 150 ° C. or higher is integrated with an electrode (positive electrode or negative electrode), the dimensions of the porous layer at a high temperature Stability can be further enhanced.
　更に、耐熱性の高い耐熱温度が１５０℃以上の微粒子を含有する本発明の多孔質層と多孔性樹脂フィルムとからセパレータを構成した場合にも、喩え多孔性樹脂フィルムが高温時の寸法安定性に劣るものであっても、耐熱温度が１５０℃以上の微粒子の作用によって高温時の寸法安定性の良好な多孔質層と一体化しているために、多孔性樹脂フィルムの熱収縮が抑制され、高温時におけるセパレータ全体の寸法安定性が向上する。そのため、本発明の多孔質層を用いた本発明のセパレータでは、例えば従来のＰＥ製多孔性フィルム（ＰＥ製微多孔膜）のみで構成されるセパレータで生じていた熱収縮に起因する短絡の発生が防止できることから、電池内が異常過熱した際の信頼性・安全性をより高めることができる。 Furthermore, even when the separator is composed of the porous layer of the present invention containing fine particles having a heat resistance of 150 ° C. or higher and a porous resin film, the porous resin film is dimensional stability at high temperatures. Even if it is inferior to the above, since it is integrated with a porous layer having good dimensional stability at high temperature by the action of fine particles having a heat resistant temperature of 150 ° C. or higher, thermal shrinkage of the porous resin film is suppressed, The overall dimensional stability of the separator at high temperatures is improved. Therefore, in the separator of the present invention using the porous layer of the present invention, for example, the occurrence of a short circuit due to heat shrinkage that occurred in a separator composed only of a conventional PE porous film (PE microporous film). Therefore, the reliability and safety when the inside of the battery is abnormally overheated can be further improved.
　本発明の多孔質層は、耐熱温度が１５０℃以上の繊維状物を含有していてもよい。例えば、多孔質層のみでセパレータを構成し、かつ多孔質層を電極と一体化しない場合には、多孔質層を補強し、その取り扱い性を高めたりする観点から、前記繊維状物を含有させることが好ましく、この繊維状物がセパレータの主体をなしていることがより好ましい。また、多孔質層と多孔質樹脂フィルムとでセパレータを構成する場合や、多孔質層を電極と一体化させる場合においても、その補強のために耐熱温度が１５０℃以上の繊維状物を含有させることができる。 The porous layer of the present invention may contain a fibrous material having a heat resistant temperature of 150 ° C. or higher. For example, in the case where the separator is constituted only by the porous layer and the porous layer is not integrated with the electrode, the fibrous material is included from the viewpoint of reinforcing the porous layer and improving its handleability. It is preferable that the fibrous material is the main component of the separator. Also, when a separator is constituted by a porous layer and a porous resin film, or when the porous layer is integrated with an electrode, a fibrous material having a heat resistant temperature of 150 ° C. or more is contained for reinforcement. be able to.
　特に、１４０℃以下の温度で溶融して、多孔質層（セパレータ）の空孔を塞ぎ、セパレータ中のイオンの移動を遮断する機能（所謂シャットダウン機能）を付与できる材料を多孔質層に含有させた場合（詳しくは後述する）、耐熱温度が１５０℃以上の繊維状物も多孔質層に含有させておくことで、電池内での発熱などによってシャットダウンが起こった後、更に２０℃以上セパレータの温度が上昇しても、その形状をより安定に保ち得るようにできる。他方、シャットダウン機能を付与していない場合でも、耐熱温度が１５０℃以上の繊維状物も用いた多孔質層を使用して構成したセパレータでは、１５０℃の温度においても、その変形を実質的になくすことができる。 In particular, the porous layer contains a material that can be melted at a temperature of 140 ° C. or lower to block the pores of the porous layer (separator) and provide a function of blocking the movement of ions in the separator (so-called shutdown function). In this case (details will be described later), a fibrous material having a heat-resistant temperature of 150 ° C. or higher is also contained in the porous layer. Even if the temperature rises, the shape can be kept more stable. On the other hand, even when the shutdown function is not given, a separator configured using a porous layer that also uses a fibrous material having a heat resistant temperature of 150 ° C. or higher substantially does not deform even at a temperature of 150 ° C. Can be eliminated.
　繊維状物は、１５０℃以上の耐熱温度を有し、かつ電気絶縁性を有しており、電気化学的に安定で、更に下記に詳述する電解液や、耐熱温度が１５０℃以上の微粒子などを含有する多孔質層形成用組成物に用いる溶媒に安定であれば、特に制限はない。なお、本明細書でいう「繊維状物」とは、アスペクト比〔長尺方向の長さ／長尺方向に直交する方向の幅（直径）〕が４以上のものを意味している。繊維状物のアスペクト比は、１０以上であることが好ましい。 The fibrous material has a heat resistant temperature of 150 ° C. or higher, has an electrical insulating property, is electrochemically stable, and further has an electrolyte solution described in detail below and fine particles having a heat resistant temperature of 150 ° C. or higher. If it is stable to the solvent used for the composition for forming a porous layer containing the above, there is no particular limitation. The “fibrous material” in the present specification means that having an aspect ratio [length in the longitudinal direction / width (diameter) in a direction perpendicular to the longitudinal direction] of 4 or more. The aspect ratio of the fibrous material is preferably 10 or more.
　繊維状物の具体的な構成材料としては、例えば、セルロース、セルロース変成体（カルボキシメチルセルロースなど）、ポリプロピレン（ＰＰ）、ポリエステル［ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリブチレンテレフタレート（ＰＢＴ）など］、ポリアクリロニトリル（ＰＡＮ）、アラミド、ポリアミドイミド、ポリイミドなどの樹脂；ガラス、アルミナ、シリカなどの無機材料（無機酸化物）；などが挙げられる。繊維状物は、これらの構成材料の１種を含有していてもよく、２種以上を含有していても構わない。また、繊維状物は、構成成分として、前記の構成材料の他に、必要に応じて、公知の各種添加剤（例えば、樹脂である場合には酸化防止剤など）を含有していても構わない。 Specific constituent materials of the fibrous material include, for example, cellulose, modified cellulose (such as carboxymethyl cellulose), polypropylene (PP), polyester [polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT). And the like], resins such as polyacrylonitrile (PAN), aramid, polyamideimide, and polyimide; inorganic materials (inorganic oxides) such as glass, alumina, and silica; and the like. The fibrous material may contain one kind of these constituent materials, or may contain two or more kinds. In addition to the above-described constituent materials, the fibrous material may contain various known additives (for example, an antioxidant in the case of a resin) as necessary. Absent.
　なお、繊維状物には、耐熱温度が１５０℃以上の微粒子との接着性を高めるために、コロナ放電処理や界面活性剤による処理などの表面処理を施してもよい。 Note that the fibrous material may be subjected to a surface treatment such as a corona discharge treatment or a treatment with a surfactant in order to enhance the adhesion with fine particles having a heat resistant temperature of 150 ° C. or higher.
　繊維状物の直径は、多孔質層の厚み以下であればよいが、例えば、０．０１～５μｍであることが好ましい。径が大きすぎると、繊維状物同士の絡み合いが不足して、これらで構成されるシート状物の強度、延いては多孔質層の強度が小さくなって取扱いが困難となることがある。また、径が小さすぎると、多孔質層の空孔が小さくなりすぎて、イオン透過性が低下する傾向にあり、電池の負荷特性を低下させてしまうことがある。 The diameter of the fibrous material may be equal to or less than the thickness of the porous layer, but is preferably 0.01 to 5 μm, for example. If the diameter is too large, the entanglement between the fibrous materials may be insufficient, and the strength of the sheet-like material constituted by these, and consequently the strength of the porous layer may be reduced, making it difficult to handle. On the other hand, if the diameter is too small, the pores of the porous layer become too small, and the ion permeability tends to decrease, which may reduce the load characteristics of the battery.
　繊維状物は、それぞれの繊維状物が独立した状態で多孔質層中に含まれていてもよく、繊維状物で構成されたシート状物（織布、不織布など）の状態で多孔質層中に含まれていてもよい。 The fibrous material may be contained in the porous layer in a state where each fibrous material is independent, and the porous layer in a sheet-like material (woven fabric, non-woven fabric, etc.) composed of the fibrous material. It may be included.
　多孔質層（シート状物）中での繊維状物の存在状態は、例えば、長軸（長尺方向の軸）の、セパレータ面に対する角度が平均で３０°以下であることが好ましく、２０°以下であることがより好ましい。 For example, the state of the fibrous material in the porous layer (sheet-like material) is preferably such that the angle of the long axis (axis in the long direction) to the separator surface is 30 ° or less on average, 20 ° The following is more preferable.
　多孔質層中における耐熱温度が１５０℃以上の微粒子の含有量は、耐熱温度が１５０℃以上の微粒子を使用することによる作用をより有効に発揮させる観点から、多孔質層の構成成分の全体積（空孔部分を除く全体積。多孔質層の各成分の含有量について、以下同じ。）中、１０体積％以上であることが好ましく、３０体積％以上であることがより好ましく、４０体積％以上であることが更に好ましい。 The content of the fine particles having a heat resistant temperature of 150 ° C. or higher in the porous layer is the total volume of the constituent components of the porous layer from the viewpoint of more effectively exerting the effect of using the fine particles having a heat resistant temperature of 150 ° C. or higher. (The total volume excluding the void portion. The same applies hereinafter for the content of each component of the porous layer.) It is preferably 10% by volume or more, more preferably 30% by volume or more, and 40% by volume. It is still more preferable that it is above.
　なお、前記の繊維状物を含有しない多孔質層であって、後記の熱溶融性微粒子や膨潤性微粒子を含有させて、シャットダウン機能も持たせる場合には、耐熱温度が１５０℃以上の微粒子の体積比率の上限は、例えば８０体積％であることが好ましい。他方、シャットダウン機能を有しない多孔質層とする場合には、耐熱温度が１５０℃以上の微粒子の体積比率は、更に高い比率でもよく、例えば９９．５体積％以下であれば問題ない。 In the case where the porous layer does not contain the fibrous material and includes a heat-fusible fine particle or a swellable fine particle, which will be described later, and has a shutdown function, the fine particle having a heat resistant temperature of 150 ° C. or higher is used. The upper limit of the volume ratio is preferably 80% by volume, for example. On the other hand, when the porous layer does not have a shutdown function, the volume ratio of the fine particles having a heat-resistant temperature of 150 ° C. or higher may be higher, for example, 99.5% by volume or less.
　他方、前記の繊維状物を含有する多孔質層であって、後記の熱溶融性微粒子や膨潤性微粒子を含有させて、シャットダウン機能も持たせる場合には、耐熱温度が１５０℃以上の微粒子の体積比率の上限は、例えば７０体積％であることが好ましい。なお、シャットダウン機能を有しない多孔質層とする場合には、耐熱温度が１５０℃以上の微粒子の体積比率は、更に高い比率でもよく、例えば８０体積％以下であれば問題ない。 On the other hand, in the case of a porous layer containing the fibrous material described above and containing a heat-fusible fine particle or a swellable fine particle, which will be described later, and having a shutdown function, a fine particle having a heat resistant temperature of 150 ° C. or higher is used. The upper limit of the volume ratio is preferably 70% by volume, for example. When the porous layer does not have a shutdown function, the volume ratio of the fine particles having a heat resistant temperature of 150 ° C. or higher may be a higher ratio, for example, 80% by volume or less.
　また、多孔質層が前記の繊維状物を含有する場合における多孔質層中の繊維状物の含有量は、繊維状物の使用による作用をより有効に発揮させる観点から、多孔質層の構成成分の全体積中、１０体積％以上であることが好ましく、３０体積％以上であることがより好ましい。他方、前記の繊維状物を含有する多孔質層において、繊維状物の含有量が多すぎると、他の成分（耐熱温度が１５０℃以上の微粒子など）の含有量が少なくなって、これら他の成分による作用が低下することがあるため、繊維状物の含有量は、多孔質層の構成成分の全体積中、９０体積％以下であることが好ましく、７０体積％以下であることがより好ましい。 In addition, when the porous layer contains the fibrous material, the content of the fibrous material in the porous layer is the configuration of the porous layer from the viewpoint of more effectively exerting the effect of using the fibrous material. The total volume of the components is preferably 10% by volume or more, and more preferably 30% by volume or more. On the other hand, in the porous layer containing the fibrous material, if the content of the fibrous material is too large, the content of other components (such as fine particles having a heat-resistant temperature of 150 ° C. or more) decreases, Therefore, the content of the fibrous material is preferably 90% by volume or less and more preferably 70% by volume or less in the total volume of the constituent components of the porous layer. preferable.
　更に、多孔質層における有機バインダの含有量は、これらの有機バインダによる作用を良好に発揮させる観点から、多孔質層の構成成分の全量中、０．５質量％以上であることが好ましい。他方、有機バインダの含有量が多すぎると、他の成分（耐熱温度が１５０℃以上の微粒子など）の含有量が少なくなって、これら他の成分による作用が低下することがあるため、多孔質層における有機バインダの含有量は、多孔質層の構成成分の全量中、１０質量％以下であることが好ましい。 Furthermore, the content of the organic binder in the porous layer is preferably 0.5% by mass or more in the total amount of the constituent components of the porous layer from the viewpoint of satisfactorily exerting the action of these organic binders. On the other hand, when the content of the organic binder is too large, the content of other components (such as fine particles having a heat-resistant temperature of 150 ° C. or higher) decreases, and the action of these other components may be reduced. The content of the organic binder in the layer is preferably 10% by mass or less in the total amount of the constituent components of the porous layer.
　本発明の多孔質層には、シャットダウン機能を付与することができる。シャットダウン機能を有する多孔質層とするには、例えば、前記多孔質層に、８０～１５０℃で溶融する熱溶融性微粒子や、非水電解液中で膨潤し、かつ温度の上昇により膨潤度が増大する膨潤性微粒子を含有させればよい。なお、多孔質層には、熱溶融性微粒子と膨潤性微粒子の両者を添加してもよく、これらの複合体を添加しても構わない。 A shutdown function can be imparted to the porous layer of the present invention. In order to obtain a porous layer having a shutdown function, for example, the porous layer swells in hot-melt fine particles that melt at 80 to 150 ° C. or in a non-aqueous electrolyte, and the degree of swelling increases with an increase in temperature. What is necessary is just to contain the swelling fine particle which increases. It should be noted that both the hot-melt fine particles and the swellable fine particles may be added to the porous layer, or a composite of these may be added.
　多孔質層における前記のシャットダウン機能は、例えば、モデルセルの温度による抵抗上昇により評価することが可能である。すなわち、正極、負極、および電解液を備え、正極および負極のうちの少なくとも一方の電極の電極合剤層上に多孔質層を有するか、または正極、負極、セパレータおよび電解液を備え、かつセパレータの少なくとも片面に多孔質層を有するモデルセルを作製し、このモデルセルを高温槽中に保持し、５℃／分の速度で昇温しながらモデルセルの内部抵抗値を測定し、測定された内部抵抗値が、加熱前（室温で測定した抵抗値）の５倍以上となる温度を測定することで、この温度を多孔質層の有するシャットダウン温度として評価することができる（後述する本発明の非水電池用セパレータについても、そのシャットダウン温度を、これと同じ方法で評価することができる）。 The shutdown function in the porous layer can be evaluated by, for example, an increase in resistance due to the temperature of the model cell. That is, a positive electrode, a negative electrode, and an electrolytic solution are provided, and a porous layer is provided on an electrode mixture layer of at least one of the positive electrode and the negative electrode, or a positive electrode, a negative electrode, a separator, and an electrolytic solution are provided, and the separator A model cell having a porous layer on at least one side of the sample cell was prepared, the model cell was held in a high-temperature bath, and the internal resistance value of the model cell was measured while increasing the temperature at a rate of 5 ° C./min. By measuring the temperature at which the internal resistance value is 5 times or more that before heating (resistance value measured at room temperature), this temperature can be evaluated as the shutdown temperature of the porous layer (of the present invention described later) The same shutdown method can be used for the nonaqueous battery separator).
　８０～１５０℃で溶融する熱溶融性微粒子、すなわち、ＪＩＳ　Ｋ　７１２１の規定に準じて、示差走査熱量計（ＤＳＣ）を用いて測定される融解温度が８０～１５０℃のものを含有する多孔質層では、多孔質層が８０～１５０℃（またはそれ以上の温度）に曝されたときに、熱溶融性微粒子が溶融して多孔質層の空孔が閉塞されるため、正極と負極との間でのリチウムイオンの移動が阻害され、高温時における急激な放電反応が抑制される。よって、この場合、前記の内部抵抗上昇により評価される多孔質層のシャットダウン温度は、熱溶融性微粒子の融点以上１５０℃以下となる。熱溶融性微粒子の融点（前記融解温度）は、１４０℃以下であることがより好ましい。 A porous material containing a heat-meltable fine particle that melts at 80 to 150 ° C., that is, a material having a melting temperature of 80 to 150 ° C. measured using a differential scanning calorimeter (DSC) according to JIS K 7121. In the layer, when the porous layer is exposed to 80 to 150 ° C. (or higher temperature), the hot-melt fine particles are melted and the pores of the porous layer are closed. The movement of lithium ions between the two is inhibited, and a rapid discharge reaction at high temperatures is suppressed. Therefore, in this case, the shutdown temperature of the porous layer evaluated by the increase in internal resistance is not less than the melting point of the heat-meltable fine particles and not more than 150 ° C. The melting point (the melting temperature) of the heat-meltable fine particles is more preferably 140 ° C. or lower.
　熱溶融性微粒子の構成材料の具体例としては、ポリエチレン（ＰＥ）、エチレン由来の構造単位が８５モル％以上の共重合ポリオレフィン、ポリプロピレン（ＰＰ）、またはポリオレフィン誘導体（塩素化ポリエチレン、塩素化ポリプロピレンなど）、ポリオレフィンワックス、石油ワックス、カルナバワックスなどが挙げられる。前記共重合ポリオレフィンとしては、エチレン－ビニルモノマー共重合体、より具体的には、エチレン－酢酸ビニル共重合体（ＥＶＡ）、エチレン－メチルアクリレート共重合体、またはエチレン－エチルアクリレート共重合体が例示できる。また、ポリシクロオレフィンなどを用いることもできる。熱溶融性微粒子は、これらの構成材料の１種のみを有していてもよく、２種以上を有していても構わない。これらの中でも、ＰＥ、ポリオレフィンワックス、またはエチレン由来の構造単位が８５モル％以上のＥＶＡが好適である。また、熱溶融性微粒子は、構成成分として、前記の構成材料の他に、必要に応じて、樹脂に添加される公知の各種添加剤（例えば、酸化防止剤など）を含有していても構わない。 Specific examples of the constituent material of the heat-meltable fine particles include polyethylene (PE), copolymerized polyolefin having a structural unit derived from ethylene of 85 mol% or more, polypropylene (PP), or polyolefin derivative (chlorinated polyethylene, chlorinated polypropylene, etc. ), Polyolefin wax, petroleum wax, carnauba wax and the like. Examples of the copolymer polyolefin include an ethylene-vinyl monomer copolymer, more specifically, an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, or an ethylene-ethyl acrylate copolymer. it can. Moreover, polycycloolefin etc. can also be used. The heat-meltable fine particles may have only one kind of these constituent materials, or may have two or more kinds. Among these, PE, polyolefin wax, or EVA having a structural unit derived from ethylene of 85 mol% or more is preferable. Further, the heat-meltable fine particles may contain various known additives (for example, antioxidants) added to the resin as necessary, in addition to the above-described constituent materials. Absent.
　熱溶融性微粒子の粒径としては、耐熱温度が１５０℃以上の微粒子と同じ測定法で測定される数平均粒子径で、例えば、０．００１μｍ以上であることが好ましく、０．１μｍ以上であることがより好ましく、また１５μｍ以下であることが好ましく、１μｍ以下であることがより好ましい。 The particle diameter of the heat-meltable fine particles is a number average particle diameter measured by the same measurement method as fine particles having a heat resistant temperature of 150 ° C. or higher, and is preferably 0.001 μm or more, for example, 0.1 μm or more. More preferably, it is preferably 15 μm or less, and more preferably 1 μm or less.
　非水電解液中で膨潤でき、かつ温度の上昇により膨潤度が増大する膨潤性微粒子を有する多孔質層を有する電池では、内部が高温になったときに、膨潤性微粒子の膨潤によって非水電解液を吸収して大きく膨張する（以下、膨潤性微粒子における温度の上昇に伴って膨潤度が増大する機能を「熱膨潤性」という）ことにより、多孔質層内のＬｉイオンの伝導性を著しく低下させるため、電池の内部抵抗が上昇し、前記のシャットダウン機能を確実に確保することが可能となる。膨潤性微粒子としては、前記の熱膨潤性を示す温度が、７５～１３５℃であるものが好ましい。 In a battery having a porous layer having swellable fine particles that can swell in a non-aqueous electrolyte and whose degree of swelling increases with an increase in temperature, the non-aqueous electrolysis is caused by swelling of the swellable fine particles when the inside becomes high temperature. It absorbs the liquid and expands greatly (hereinafter, the function of increasing the degree of swelling as the temperature rises in the swellable fine particles is called “thermal swellability”), thereby significantly increasing the conductivity of Li ions in the porous layer. Therefore, the internal resistance of the battery is increased, and the shutdown function can be reliably ensured. As the swellable fine particles, those having a temperature showing the above-mentioned heat swellability are preferably 75 to 135 ° C.
　このような熱膨潤性を有する膨潤性微粒子としては、例えば、架橋ポリスチレン（ＰＳ）、架橋アクリル樹脂〔例えば、架橋ポリメチルメタクリレート（ＰＭＭＡ）〕、架橋フッ素樹脂〔例えば、架橋ポリフッ化ビニリデン（ＰＶＤＦ）〕などが好適であり、架橋ＰＭＭＡが特に好ましい。 Examples of such swellable fine particles having thermal swellability include cross-linked polystyrene (PS), cross-linked acrylic resin [for example, cross-linked polymethyl methacrylate (PMMA)], cross-linked fluororesin [for example, cross-linked polyvinylidene fluoride (PVDF) ] Is preferred, and cross-linked PMMA is particularly preferred.
　膨潤性微粒子の粒径は、レーザー散乱粒度分布計（例えば、ＨＯＲＩＢＡ社製「ＬＡ－９２０」）を用い、微粒子を膨潤しない媒体（例えば水）に分散させて測定した数平均粒子径で、０．１～２０μｍであることが好ましい。 The particle size of the swellable fine particles is a number average particle size measured by dispersing the fine particles in a non-swelling medium (for example, water) using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA). It is preferably 1 to 20 μm.
　膨潤性微粒子の市販品としては、例えば、ガンツ化成社製の架橋ＰＭＭＡ「ガンツパール（製品名）」、東洋インキ社製の架橋ＰＭＭＡ「ＲＳＰ１０７９（製品名）」などが入手可能である。 As commercially available products of swellable fine particles, for example, cross-linked PMMA “Gantz Pearl (product name)” manufactured by Ganz Kasei Co., Ltd., and cross-linked PMMA “RSP1079 (product name)” manufactured by Toyo Ink Co., Ltd. are available.
　なお、熱溶融性微粒子や膨潤性微粒子を多孔質層に含有させることでシャットダウン機能を持たせる場合、良好なシャットダウン機能を確保する点からは、多孔質層中における熱溶融性微粒子および／または膨潤性微粒子の含有量は、多孔質層の構成成分の全体積中、５～７０体積％であることが好ましい。これらの微粒子の含有量が少なすぎると、これらを含有させることによるシャットダウン効果が小さくなることがあり、多すぎると、多孔質層中における耐熱温度が１５０℃以上の微粒子や繊維状物の含有量が減ることになるため、これらによって確保される効果が小さくなることがある。 In addition, when a thermal shutdown fine particle or a swelling fine particle is included in the porous layer so as to have a shutdown function, the thermal meltable fine particle and / or swelling in the porous layer is required in order to ensure a good shutdown function. The content of the conductive fine particles is preferably 5 to 70% by volume in the total volume of the constituent components of the porous layer. If the content of these fine particles is too small, the shutdown effect due to the inclusion of these may be reduced, and if too large, the content of fine particles or fibrous materials having a heat resistance temperature of 150 ° C. or higher in the porous layer. Therefore, the effect secured by these may be reduced.
　本発明の多孔質層の厚みは、０．５μｍ以上であることが好ましく、１μｍ以上であることがより好ましく、２μｍ以上であることが更に好ましく、また、１０μｍ以下であることが好ましく、５μｍ以下であることがより好ましい。 The thickness of the porous layer of the present invention is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, and preferably 10 μm or less, preferably 5 μm or less. It is more preferable that
　また、本発明の多孔質層の空孔率は、２０～６０％であることが好ましい。多孔質層の空孔率は、多孔質層の厚み、面積あたりの質量、構成成分の密度から、下記式（３）を用いて各成分ｉについての総和を求めることにより計算できる。
　　Ｐ ＝　１００－（Σａｉ／ρｉ）×（ｍ／ｔ）　　　　　　（３） In addition, the porosity of the porous layer of the present invention is preferably 20 to 60%. The porosity of the porous layer can be calculated by calculating the sum of each component i from the thickness of the porous layer, the mass per area, and the density of the constituent components using the following formula (3).
P = 100− (Σa i / ρ i ) × (m / t) (3)
　ここで、前記式（３）中、ａｉ：質量％で表した成分ｉの比率、ρｉ：成分ｉの密度（ｇ／ｃｍ３）、ｍ：多孔質層の単位面積あたりの質量（ｇ／ｃｍ２）、ｔ：多孔質層の厚み（ｃｍ）である。 Here, in the formula (3), a i : ratio of the component i expressed by mass%, ρ i : density of the component i (g / cm 3 ), m: mass per unit area of the porous layer (g / Cm 2 ), t: thickness of the porous layer (cm).
　本発明の多孔質層は、耐熱温度が１５０℃以上の微粒子および有機バインダ、更には必要に応じて使用される繊維状物、熱溶融性微粒子、膨潤性微粒子などを含有する多孔質層形成用組成物（溶媒を含む組成物）を、基材となる多孔質樹脂フィルム（本発明の非水電池用セパレータとする場合）上や、非水電池用の電極の電極合剤層（本発明の非水電池用電極とする場合）上に塗布し、乾燥する工程を経て形成することができる。 The porous layer of the present invention is for forming a porous layer containing fine particles having an heat-resistant temperature of 150 ° C. or more and an organic binder, as well as fibrous materials, heat-meltable fine particles, swellable fine particles and the like used as necessary. The composition (composition containing a solvent) is used on a porous resin film (in the case of the separator for a non-aqueous battery of the present invention) as a base material, or an electrode mixture layer of the electrode for a non-aqueous battery (of the present invention). The electrode can be formed on a nonaqueous battery electrode) and then dried.
　また、多孔質層が繊維状物のシート状物（織布、不織布など）を含む場合には、例えば、シート状物を多孔質層形成用組成物中に含浸させ、必要に応じてギャップに通して多孔質層形成用組成物のシート状物の空隙中への侵入を促進させたり、シート状物に多孔質層形成用組成物を塗布した後にギャップに通して多孔質層形成用組成物をシート状物の空隙中へ侵入させたりした後に、乾燥する工程を経て多孔質層を形成することもできる。 When the porous layer contains a fibrous sheet (woven fabric, non-woven fabric, etc.), for example, the porous layer forming composition is impregnated with the sheet, and the gap is formed as necessary. The composition for forming a porous layer is promoted to penetrate into the voids of the sheet-like material, or the composition for forming a porous layer is applied to the sheet-like material through the gap after being applied. It is also possible to form a porous layer through a step of drying after intruding into the voids of the sheet-like material.
　多孔質層形成用組成物は、耐熱温度が１５０℃以上の微粒子および有機バインダ、更には必要に応じて使用される繊維状物、熱溶融性微粒子、膨潤性微粒子などを含有し、これらを溶媒（分散媒を含む。以下同じ。）に分散させたものである。なお、有機バインダについては溶媒に溶解させることもできる。多孔質層形成用組成物に用いられる溶媒は、前記の各微粒子を均一に分散でき、また、有機バインダを均一に溶解または分散できるものであればよいが、例えば、トルエンなどの芳香族炭化水素、テトラヒドロフランなどのフラン類、メチルエチルケトン、メチルイソブチルケトンなどのケトン類など、一般的な有機溶媒が好適に用いられる。なお、これらの溶媒に、界面張力を制御する目的で、アルコール（エチレングリコール、プロピレングリコールなど）、または、モノメチルアセテートなどの各種プロピレンオキサイド系グリコールエーテルなどを適宜添加してもよい。また、有機バインダが水溶性である場合、エマルジョンとして使用する場合などでは、水を溶媒としてもよく、この際にもアルコール類（メチルアルコール、エチルアルコール、イソプロピルアルコール、エチレングリコールなど）を適宜加えて界面張力を制御することもできる。 The composition for forming a porous layer contains fine particles having an heat resistant temperature of 150 ° C. or more and an organic binder, as well as fibrous materials, hot-melt fine particles, swellable fine particles, and the like, which are used as necessary. (Including a dispersion medium, the same shall apply hereinafter). The organic binder can be dissolved in a solvent. The solvent used in the composition for forming a porous layer may be any solvent as long as it can uniformly disperse the fine particles, and can uniformly dissolve or disperse the organic binder. For example, an aromatic hydrocarbon such as toluene. Common organic solvents such as francs such as tetrahydrofuran, ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferably used. In addition, for the purpose of controlling the interfacial tension, alcohols (ethylene glycol, propylene glycol, etc.) or various propylene oxide glycol ethers such as monomethyl acetate may be appropriately added to these solvents. In addition, when the organic binder is water-soluble or used as an emulsion, water may be used as a solvent. In this case, alcohols (methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, etc.) are appropriately added. It is also possible to control the interfacial tension.
　多孔質層形成用組成物は、耐熱温度が１５０℃以上の微粒子および有機バインダなどを含む固形分含量を、例えば１０～８０質量％とすることが好ましい。 The composition for forming a porous layer preferably has a solid content including fine particles having an heat resistant temperature of 150 ° C. or higher and an organic binder, for example, 10 to 80% by mass.
　耐熱温度が１５０℃以上の微粒子として板状粒子を用いた場合、その配向性を高めるには、多孔質層形成用組成物を基材（多孔質樹脂フィルムや電極、繊維状物のシート状物）に塗布する際に、前記組成物のシェアをかける方法；高固形分濃度（例えば５０～８０質量％）の多孔質層形成用組成物を使用する方法；耐熱温度が１５０℃以上の微粒子を溶媒に、ディスパー、アジター、ホモジナイザー、ボールミル、アトライター、ジェットミルなどの各種混合・攪拌装置、分散装置などを用いて分散させ、得られた分散体にバインダ（更に、必要に応じて繊維状物、熱溶融性微粒子、膨潤性微粒子など）を添加・混合して調製した多孔質層形成用組成物を使用する方法；表面に油脂類、界面活性剤、シランカップリング剤などの分散性剤を作用させて、表面を改質した耐熱温度が１５０℃以上の微粒子を用いて調製した多孔質層形成用組成物を使用する方法；形状、径またはアスペクト比の異なる耐熱温度が１５０℃以上の微粒子を併用して調製した多孔質層形成用組成物を使用する方法；多孔質層形成用組成物を基材上に塗布した後の乾燥条件を制御する方法；本発明の多孔質層を有するセパレータ（本発明のセパレータ）の場合には、セパレータ全体を加圧や加熱加圧プレスする方法；多孔質層形成用組成物を基材上に塗布した後、乾燥前に磁場をかける方法；などが採用でき、これらの方法をそれぞれ単独で実施してもよく、２種以上の方法を組み合わせて実施してもよい。 When plate-like particles are used as fine particles having a heat-resistant temperature of 150 ° C. or higher, the composition for forming a porous layer is used as a base material (porous resin film, electrode, or fibrous sheet-like material) in order to increase the orientation. ) A method of applying a share of the above composition; a method of using a composition for forming a porous layer having a high solid content concentration (for example, 50 to 80% by mass); and fine particles having a heat resistant temperature of 150 ° C. or more. Disperse in a solvent using various mixing / stirring devices such as dispersers, agitators, homogenizers, ball mills, attritors, jet mills, dispersing devices, etc., and a binder (and fibrous material if necessary) , Heat-meltable fine particles, swellable fine particles, etc.), and a method for using the composition for forming a porous layer prepared by adding and mixing; dispersants such as fats and oils, surfactants and silane coupling agents on the surface A method for using a porous layer forming composition prepared by using fine particles having a heat-resistant temperature of 150 ° C. or higher whose surface has been modified; fine particles having a heat-resistant temperature of 150 ° C. or higher having different shapes, diameters or aspect ratios A method using a composition for forming a porous layer prepared in combination with a composition; a method for controlling drying conditions after the composition for forming a porous layer is applied on a substrate; a separator having the porous layer of the present invention In the case of (separator of the present invention), a method of pressurizing or heating and pressing the whole separator; a method of applying a magnetic field before drying after applying the porous layer forming composition on a substrate; These methods can be employed alone or in combination of two or more methods.
　本発明の非水電池用セパレータ（以下、単に「セパレータ」という）は、本発明の多孔質層を多孔質樹脂フィルム上に形成したものである。 The nonaqueous battery separator of the present invention (hereinafter simply referred to as “separator”) is obtained by forming the porous layer of the present invention on a porous resin film.
　本発明のセパレータにおいて、多孔質樹脂フィルムによってシャットダウン機能を確保する場合、多孔質樹脂フィルムを構成する樹脂には、前記熱溶融性微粒子を構成する樹脂と同様の樹脂（熱可塑性樹脂）を使用することができる。なお、多孔質樹脂フィルムのシャットダウン温度は８０℃～１５０℃の範囲に設定することが望ましく、従ってこれを構成する熱可塑性樹脂にも、融点が８０～１５０℃のものを用いることが望ましい。 In the separator of the present invention, when the shutdown function is secured by the porous resin film, the same resin (thermoplastic resin) as the resin constituting the heat-meltable fine particles is used as the resin constituting the porous resin film. be able to. The shutdown temperature of the porous resin film is desirably set in the range of 80 ° C. to 150 ° C. Therefore, it is desirable to use a thermoplastic resin having a melting point of 80 to 150 ° C.
　他方、セパレータの耐熱性を重視して、シャットダウン機能を付与しない場合には、耐熱性の多孔質樹脂フィルムを用いることもできる。このような多孔質樹脂フィルムの具体的な構成材料としては、耐熱温度が１５０℃以上で、電池に用いる非水電解液に対して安定であり、更に電池内部での酸化還元反応に対して安定である樹脂であればいずれでもよい。より具体的には、ポリイミド、ポリアミドイミド、アラミド、ポリテトラフルオロエチレン、ポリスルホン、ポリウレタン、ＰＡＮ、ポリエステル（ＰＥＴ、ＰＢＴ、ＰＥＮなど）などの耐熱性樹脂が挙げられる。 On the other hand, when the heat resistance of the separator is emphasized and the shutdown function is not provided, a heat resistant porous resin film can be used. As a specific constituent material of such a porous resin film, the heat resistant temperature is 150 ° C. or more, it is stable to a non-aqueous electrolyte used in a battery, and further stable to a redox reaction inside the battery. Any resin can be used. More specifically, heat-resistant resins such as polyimide, polyamideimide, aramid, polytetrafluoroethylene, polysulfone, polyurethane, PAN, polyester (PET, PBT, PEN, etc.) can be mentioned.
　多孔質樹脂フィルムには、例えば、従来公知の非水電池などで使用されている前記例示の樹脂で構成された多孔質フィルム、すなわち、溶剤抽出法、乾式または湿式延伸法などにより作製されたイオン透過性の多孔質フィルム（微多孔膜）を用いることができる。また、薬剤や超臨界ＣＯ２などを用いた発泡法により微多孔化したフィルムを用いることもできる。 The porous resin film includes, for example, a porous film composed of the above-described exemplary resins used in conventionally known non-aqueous batteries, that is, ions produced by a solvent extraction method, a dry or wet stretching method, and the like. A permeable porous film (microporous film) can be used. In addition, a film microporous by a foaming method using a drug, supercritical CO 2 or the like can also be used.
　本発明のセパレータにおいては、本発明の多孔質層の作用によって、多孔質樹脂フィルムに熱収縮しやすいものを適用しても良好な耐熱性（耐熱収縮性）を確保し得ることから、例えば、良好なシャットダウン機能を確保し得る多孔質樹脂フィルムを採用することが好ましく、ポリオレフィン（ＰＥ、ＰＰ、エチレン－プロピレン共重合体など）製の多孔質フィルム（微多孔膜）を用いることがより好ましい。 In the separator of the present invention, because of the action of the porous layer of the present invention, it is possible to ensure good heat resistance (heat shrinkage resistance) even when a porous resin film that is easily heat-shrinkable is applied. It is preferable to employ a porous resin film that can ensure a good shutdown function, and it is more preferable to use a porous film (microporous film) made of polyolefin (PE, PP, ethylene-propylene copolymer, etc.).
　本発明のセパレータにおいては、多孔質層および多孔質樹脂フィルムは、それぞれ１層ずつである必要はなく、一方または両方が２層以上であってもよいが、セパレータの層数をあまり増やしすぎることは好ましくなく、例えば、多孔質層および多孔質樹脂フィルムの総層数が５層以下であることが好ましい。 In the separator of the present invention, the porous layer and the porous resin film do not need to be one each, and one or both may be two or more layers, but the number of layers of the separator is excessively increased. For example, the total number of layers of the porous layer and the porous resin film is preferably 5 or less.
　セパレータを適用する非水電池の短絡防止効果をより高め、セパレータの強度を確保して、その取り扱い性を良好とする観点から、本発明のセパレータの厚みは、例えば、３μｍ以上とすることが好ましく、５μｍ以上とすることがより好ましい。他方、セパレータを適用する非水電池のエネルギー密度をより高める観点からは、セパレータの厚みは、５０μｍ以下とすることが好ましく、３０μｍ以下とすることがより好ましい。 From the viewpoint of enhancing the short-circuit prevention effect of the non-aqueous battery to which the separator is applied, ensuring the strength of the separator, and improving its handleability, the thickness of the separator of the present invention is preferably 3 μm or more, for example. More preferably, it is 5 μm or more. On the other hand, from the viewpoint of further increasing the energy density of the nonaqueous battery to which the separator is applied, the thickness of the separator is preferably 50 μm or less, and more preferably 30 μm or less.
　また、多孔質層の厚みをＸ（μｍ）、多孔質樹脂フィルムの厚みをＹ（μｍ）としたとき、ＸとＹとの比率Ｙ／Ｘを１～２０としつつ、セパレータ全体の厚みが前記好適値を満足するようにすることが好ましい。Ｙ／Ｘが大きすぎると、多孔質層が薄くなりすぎて、例えば、多孔質樹脂フィルムの高温時での寸法安定性が劣る場合に、その熱収縮を抑制する効果が小さくなる虞がある。また、Ｙ／Ｘが小さすぎると、多孔質層が厚くなりすぎて、セパレータ全体の厚みを増大させ、負荷特性などの電池特性の低下を引き起こす虞がある。なお、セパレータが、多孔質層を複数枚有する場合には、厚みＸはその総厚みであり、多孔質樹脂フィルムを複数枚有する場合には、厚みＹはその総厚みである。 In addition, when the thickness of the porous layer is X (μm) and the thickness of the porous resin film is Y (μm), the ratio Y / X between X and Y is 1 to 20, and the thickness of the entire separator is It is preferable to satisfy a suitable value. If Y / X is too large, the porous layer becomes too thin. For example, when the dimensional stability of the porous resin film at high temperatures is poor, the effect of suppressing the thermal shrinkage may be reduced. On the other hand, if Y / X is too small, the porous layer becomes too thick, increasing the thickness of the entire separator, and possibly causing deterioration of battery characteristics such as load characteristics. When the separator has a plurality of porous layers, the thickness X is the total thickness, and when the separator has a plurality of porous resin films, the thickness Y is the total thickness.
　なお、多孔質樹脂フィルムの厚み（セパレータが多孔質樹脂フィルムを複数枚有する場合には、その総厚み）を具体的な値で表現すると、５μｍ以上であることが好ましく、また、３０μｍ以下であることが好ましい。また、セパレータにおける多孔質層の厚みに関しては、セパレータが多孔質層を複数有する場合には、その総厚みが、先に述べた多孔質層の好適厚みを満たしていることが好ましい。 When the thickness of the porous resin film (when the separator has a plurality of porous resin films, the total thickness) is expressed by a specific value, it is preferably 5 μm or more, and 30 μm or less. It is preferable. Regarding the thickness of the porous layer in the separator, when the separator has a plurality of porous layers, it is preferable that the total thickness satisfies the preferred thickness of the porous layer described above.
　また、本発明のセパレータは、実施例に記載の方法で測定される非水電解液（その溶媒）中、１５０℃での熱収縮率が、５％以下であることが好ましい。これまでに説明した構成のセパレータとすることで、かかる熱収縮率を確保することができる。 Further, the separator of the present invention preferably has a thermal shrinkage rate at 150 ° C. of 5% or less in the nonaqueous electrolytic solution (the solvent) measured by the method described in the examples. By using the separator having the configuration described so far, such a heat shrinkage rate can be ensured.
　また、セパレータの空孔率は、非水電解液の保液量を確保してイオン透過性を良好にするために、乾燥した状態で、２０％以上であることが好ましく、３０％以上であることがより好ましい。一方、セパレータ強度の確保と内部短絡の防止の観点から、セパレータの空孔率は、乾燥した状態で、７０％以下であることが好ましく、６０％以下であることがより好ましい。なお、セパレータの空孔率：Ｐ（％）は、前記式（３）において、ｍをセパレータの単位面積あたりの質量（ｇ／ｃｍ２）とし、ｔをセパレータの厚み（ｃｍ）とすることで、前記式（３）を用いて求めることができる。 In addition, the porosity of the separator is preferably 20% or more, and preferably 30% or more in a dried state, in order to ensure the amount of the nonaqueous electrolyte retained and to improve the ion permeability. It is more preferable. On the other hand, from the viewpoint of ensuring the strength of the separator and preventing internal short circuit, the porosity of the separator is preferably 70% or less, more preferably 60% or less, in a dry state. Note that the porosity of the separator: P (%) is obtained by setting m as the mass per unit area of the separator (g / cm 2 ) and t as the thickness of the separator (cm) in the above formula (3). , Can be obtained using the above equation (3).
　更に、前記式（３）において、ｍを多孔質樹脂フィルムの単位面積あたりの質量（ｇ／ｃｍ２）とし、ｔを多孔質樹脂フィルムの厚み（ｃｍ）とすることで、前記式（３）を用いて多孔質樹脂フィルムの空孔率：Ｐ（％）を求めることもできる。この方法により求められる多孔質樹脂フィルムの空孔率は、３０～７０％であることが好ましい。 Furthermore, in the said Formula (3), m is the mass per unit area (g / cm < 2 >) of a porous resin film, and t is the thickness (cm) of a porous resin film, The said Formula (3) Can also be used to determine the porosity of the porous resin film: P (%). The porosity of the porous resin film obtained by this method is preferably 30 to 70%.
　更に、セパレータの強度としては、直径が１ｍｍのニードルを用いた突き刺し強度で５０ｇ以上であることが望ましい。かかる突き刺し強度が小さすぎると、リチウムのデンドライト結晶が発生した場合に、セパレータの突き敗れによる短絡が発生する虞がある。 Furthermore, the strength of the separator is desirably 50 g or more in terms of piercing strength using a needle having a diameter of 1 mm. If the piercing strength is too low, a short circuit may occur due to the piercing of the separator when lithium dendrite crystals are generated.
　また、セパレータの透気度は、ＪＩＳ　Ｐ　８１１７に準拠した方法で測定され、０．８７９ｇ／ｍｍ２の圧力下で１００ｍｌの空気が膜を透過する秒数で示されるガーレー値で１０～３００ｓｅｃであることが望ましい。透気度が大きすぎると、イオン透過性が小さくなり、小さすぎるとセパレータの強度が小さくなることがある。 The air permeability of the separator is measured by a method in accordance with JIS P 8117, and is a Gurley value indicated by the number of seconds that 100 ml of air passes through the membrane under a pressure of 0.879 g / mm 2 , and is 10 to 300 sec. It is desirable to be. If the air permeability is too high, the ion permeability is reduced, and if it is too low, the strength of the separator may be reduced.
　更にセパレータのガーレー値は下記式（４）の関係を満たすことが望ましい。
　　Ｇｓ≦ｍａｘ｛Ｇａ，Ｇｂ｝＋１０　（４） Furthermore, it is desirable that the Gurley value of the separator satisfies the relationship of the following formula (4).
Gs ≦ max {Ga, Gb} +10 (4)
　前記式（４）中、Ｇｓ：セパレータのガーレー値、Ｇａ：多孔質樹脂フィルムのガーレー値、Ｇｂ：本発明の多孔質層のガーレー値、ｍａｘ｛ａ，ｂ｝：ａとｂのどちらか大きい方である。ただし、Ｇｂは、下記式（５）を用いて求める。
　　Ｇｂ＝Ｇｓ－Ｇａ　（５） In the above formula (4), Gs: Gurley value of the separator, Ga: Gurley value of the porous resin film, Gb: Gurley value of the porous layer of the present invention, max {a, b}: whichever is greater than a or b Is. However, Gb is calculated | required using following formula (5).
Gb = Gs-Ga (5)
　前記の突き刺し強度や透気度は、これまでに説明した構成のセパレータとすることで確保できる。 The puncture strength and air permeability described above can be ensured by using a separator having the structure described above.
　本発明のセパレータにおいて、多孔質層と多孔質樹脂フィルムとの間の１８０°の剥離強度は、０．６Ｎ／ｃｍ以上であることが好ましく、１．０Ｎ／ｃｍ以上であることがより好ましい。ここでいう剥離強度とは、以下の方法により測定される値である。セパレータから長さ５ｃｍ×２ｃｍの大きさに切り出した試験片に、多孔質層表面の２ｃｍ×２ｃｍの領域に粘着テープを貼り付ける。なお、粘着テープのサイズは幅２ｃｍ、長さ約５ｃｍで、粘着テープの片端と多孔質層の片端とが揃うように貼り付ける。その後、引張試験機を用い、試験片における粘着テープを貼り付けた方とは反対側の端と、試験片に貼り付けた粘着テープにおける試験片に貼り付けた方とは反対側の端とを把持して、引張速度１０ｍｍ／ｍｉｎで引っ張り、多孔質層が剥離した時の強度を測定する。 In the separator of the present invention, the 180 ° peel strength between the porous layer and the porous resin film is preferably 0.6 N / cm or more, and more preferably 1.0 N / cm or more. The peel strength here is a value measured by the following method. An adhesive tape is attached to a 2 cm × 2 cm region on the surface of the porous layer on a test piece cut out in a size of 5 cm × 2 cm from the separator. The adhesive tape has a width of 2 cm and a length of about 5 cm, and is attached so that one end of the adhesive tape and one end of the porous layer are aligned. Then, using a tensile tester, the end of the test piece on the opposite side of the adhesive tape and the end of the adhesive tape attached to the test piece on the opposite side of the test piece Gripping and pulling at a pulling speed of 10 mm / min to measure the strength when the porous layer is peeled off.
　本発明のセパレータは、多孔質層（本発明の多孔質層）が、接着性に優れる前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体であって、前記の共重合比を満たすものを有機バインダとして使用していることから、多孔質層と多孔質樹脂フィルムとの間の剥離強度を前記のように高めることができる。また、前記一般式（１）で表されるＮ－ビニルカルボン酸アミドと前記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体であって、前記の共重合比を満たすものは、高温の非水電解液（非水電解液溶媒）中での耐性に優れていることから、本発明のセパレータが使用された非水電池内が高温となっても、多孔質層と多孔質樹脂フィルムとの間の剥離強度を高い値に維持できるため、多孔質層の作用によってセパレータ全体の収縮を高度に抑制することが可能であり、より安全性の高い非水電池を構成できる。 In the separator of the present invention, the porous layer (the porous layer of the present invention) is represented by the general formula (1) and the N-vinylcarboxylic amide represented by the general formula (1), which is excellent in adhesiveness. Since a copolymer with an unsaturated carboxylic acid monomer that satisfies the copolymerization ratio is used as the organic binder, the peel strength between the porous layer and the porous resin film is Can be raised like. And a copolymer of the N-vinylcarboxylic amide represented by the general formula (1) and the unsaturated carboxylic acid monomer represented by the general formula (2), wherein the copolymerization ratio is What is filled is excellent in resistance in a high-temperature non-aqueous electrolyte (non-aqueous electrolyte solvent), so even if the temperature of the non-aqueous battery in which the separator of the present invention is used becomes high, the porous layer Since the peel strength between the film and the porous resin film can be maintained at a high value, it is possible to highly suppress the shrinkage of the entire separator due to the action of the porous layer, and to construct a safer non-aqueous battery it can.
　本発明の非水電池用電極（以下、単に「電極」という）は、本発明の多孔質層を電極合剤層（正極合剤層または負極合剤層）上に形成したものである。本発明の電極は、非水電池の正極または負極に使用される。なお、本発明の電極が使用される電池としては、非水一次電池と非水二次電池とがあるが、以下には、本発明の電極が使用される電池として主要な非水二次電池に適した構成の電極の詳細について説明する。 The nonaqueous battery electrode of the present invention (hereinafter simply referred to as “electrode”) is obtained by forming the porous layer of the present invention on an electrode mixture layer (positive electrode mixture layer or negative electrode mixture layer). The electrode of the present invention is used for a positive electrode or a negative electrode of a nonaqueous battery. In addition, as a battery in which the electrode of the present invention is used, there are a non-aqueous primary battery and a non-aqueous secondary battery. Hereinafter, the main non-aqueous secondary battery is used as a battery in which the electrode of the present invention is used. Details of the electrode having a configuration suitable for the above will be described.
　非水電池の正極に使用される場合の本発明の電極としては、例えば、正極活物質、導電助剤およびバインダなどを含有する電極合剤層（正極合剤層）を、集電体の片面または両面に有し、かつこれらの電極合剤層上に、本発明の多孔質層が形成された構造のものが挙げられる。 As an electrode of the present invention when used for a positive electrode of a nonaqueous battery, for example, an electrode mixture layer (positive electrode mixture layer) containing a positive electrode active material, a conductive additive, a binder, and the like is used. Alternatively, a structure having a structure in which the porous layer of the present invention is formed on both electrode mixture layers on both surfaces is exemplified.
　正極活物質としては、例えば、ＬｉＣｏＯ２などのリチウムコバルト酸化物；ＬｉＭｎＯ２、Ｌｉ２ＭｎＯ３などのリチウムマンガン酸化物；ＬｉＮｉＯ２などのリチウムニッケル酸化物；ＬｉＭｎ２Ｏ４、Ｌｉ４／３Ｔｉ５／３Ｏ４などのスピネル構造のリチウム含有複合酸化物；ＬｉＦｅＰＯ４などのオリビン構造のリチウム含有複合酸化物；前記の酸化物を基本組成とし各種元素で置換した酸化物；などが挙げられ、これらのうちの１種のみを用いてもよく、２種以上を併用してもよい。 Examples of the positive electrode active material include lithium cobalt oxides such as LiCoO 2 ; lithium manganese oxides such as LiMnO 2 and Li 2 MnO 3 ; lithium nickel oxides such as LiNiO 2 ; LiMn 2 O 4 and Li 4/3 Ti 5/3 O 4 and other spinel-structured lithium-containing composite oxides; LiFePO 4 and other olivine-structured lithium-containing composite oxides; oxides obtained by substituting the above-mentioned oxides with various elements; Only one of these may be used, or two or more may be used in combination.
　正極合剤層に係る導電助剤には、例えば、天然黒鉛（鱗片状黒鉛など）、人造黒鉛などのグラファイト類；アセチレンブラック、ケッチェンブラック、チャンネルブラック、ファーネスブラック、ランプブラック、サーマルブラックなどのカ－ボンブラック類；炭素繊維；などの炭素材料を用いることが好ましく、また、金属繊維などの導電性繊維類；フッ化カーボン；アルミニウムなどの金属粉末類；酸化亜鉛；チタン酸カリウムなどの導電性ウィスカー類；酸化チタンなどの導電性金属酸化物；ポリフェニレン誘導体などの有機導電性材料；などを用いることもできる。 Examples of the conductive auxiliary agent related to the positive electrode mixture layer include graphites such as natural graphite (flaky graphite, etc.) and artificial graphite; acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc. It is preferable to use carbon materials such as carbon blacks; carbon fibers; and conductive fibers such as metal fibers; carbon fluorides; metal powders such as aluminum; zinc oxide; and conductive materials such as potassium titanate. Conductive whiskers; conductive metal oxides such as titanium oxide; organic conductive materials such as polyphenylene derivatives; and the like can also be used.
　正極合剤層に係るバインダとしては、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、スチレンブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース（ＣＭＣ）、ポリビニルピロリドン（ＰＶＰ）などが挙げられる。 Examples of the binder related to the positive electrode mixture layer include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), and the like.
　正極は、例えば、正極活物質、導電助剤およびバインダなどを含有する正極合剤を、Ｎ－メチル－２－ピロリドン（ＮＭＰ）や水などの溶剤に分散させてペースト状やスラリー状の正極合剤含有組成物を調製し（ただし、バインダは溶剤に溶解していてもよい）、これを集電体の片面または両面に塗布し、乾燥した後に、必要に応じてカレンダー処理を施し、更にこの正極を基材として、その正極合剤層上に、前記の方法で本発明の多孔質層を形成する工程を経て製造することができる。ただし、正極は、前記の方法で製造されたものに限定される訳ではなく、他の方法で製造したものであってもよい。 For example, a positive electrode mixture containing a positive electrode active material, a conductive additive, a binder, and the like is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) or water to form a paste-like or slurry-like positive electrode mixture. An agent-containing composition is prepared (however, the binder may be dissolved in a solvent), applied to one or both sides of the current collector, dried, and then subjected to a calender treatment as necessary. Using the positive electrode as a base material, it can be produced through the step of forming the porous layer of the present invention on the positive electrode mixture layer by the method described above. However, the positive electrode is not limited to those manufactured by the above method, and may be manufactured by other methods.
　正極集電体には、アルミニウム製の箔、パンチングメタル、網、エキスパンドメタルなどを用い得るが、通常、アルミニウム箔が用いられる。正極集電体の厚みは、１０～３０μｍであることが好ましい。 As the positive electrode current collector, aluminum foil, punching metal, net, expanded metal, or the like can be used, but aluminum foil is usually used. The thickness of the positive electrode current collector is preferably 10 to 30 μm.
　また、正極には、必要に応じて、非水電池内の他の部材と電気的に接続するためのリード体を、常法に従って形成してもよい。 Further, a lead body for electrical connection with other members in the non-aqueous battery may be formed on the positive electrode according to a conventional method, if necessary.
　正極合剤層の組成としては、例えば、正極活物質の含有量が８０．０～９９．８質量％であることが好ましく、導電助剤の含有量が０．１～１０質量％であることが好ましく、バインダの含有量が０．１～１０質量％であることが好ましい。また、正極合剤層の厚みは、集電体の片面あたり、１～１００μｍであることが好ましい。 As the composition of the positive electrode mixture layer, for example, the content of the positive electrode active material is preferably 80.0 to 99.8% by mass, and the content of the conductive auxiliary agent is 0.1 to 10% by mass. The binder content is preferably 0.1 to 10% by mass. The thickness of the positive electrode mixture layer is preferably 1 to 100 μm per side of the current collector.
　非水電池の負極に使用される場合の本発明の電極としては、例えば、負極活物質およびバインダ、更には必要に応じて導電助剤などを含有する電極合剤層（負極合剤層）を、集電体の片面または両面に有し、かつこれらの電極合剤層上に、本発明の多孔質層が形成された構造のものが挙げられる。 As an electrode of the present invention when used for a negative electrode of a nonaqueous battery, for example, an electrode mixture layer (a negative electrode mixture layer) containing a negative electrode active material and a binder, and further, if necessary, a conductive additive, etc. And a structure in which the porous layer of the present invention is formed on one or both surfaces of the current collector and on the electrode mixture layer.
　負極活物質としては、リチウムイオンをドープ・脱ドープできるものであればよく、例えば、黒鉛、熱分解炭素類、コークス類、ガラス状炭素、有機高分子化合物の焼成体、メソカーボンマイクロビーズ、炭素繊維、活性炭などの炭素質材料が挙げられる。また、リチウムまたはリチウム含有化合物なども負極活物質として使用することができる。前記のリチウム含有化合物としては、例えば、錫酸化物、ケイ素酸化物、ニッケル－ケイ素系合金、マグネシウム－ケイ素系合金、タングステン酸化物、リチウム鉄複合酸化物などの他、リチウム－アルミニウム、リチウム－鉛、リチウム－インジウム、リチウム－ガリウム、リチウム－インジウム－ガリウムなどのリチウム合金が挙げられる。これら例示の負極活物質の中には、製造時にはリチウムを含んでいないものもあるが、充電時にはリチウムを含んだ状態になる。 The negative electrode active material may be any material that can be doped / undoped with lithium ions. For example, graphite, pyrolytic carbons, cokes, glassy carbon, fired organic polymer compound, mesocarbon microbeads, carbon Examples thereof include carbonaceous materials such as fibers and activated carbon. Moreover, lithium or a lithium-containing compound can also be used as the negative electrode active material. Examples of the lithium-containing compound include tin oxide, silicon oxide, nickel-silicon alloy, magnesium-silicon alloy, tungsten oxide, lithium iron composite oxide, lithium-aluminum, and lithium-lead. And lithium alloys such as lithium-indium, lithium-gallium, and lithium-indium-gallium. Some of these exemplary negative electrode active materials do not contain lithium at the time of manufacture, but are in a state containing lithium at the time of charging.
　負極合剤層に係るバインダには、正極合剤層に係るバインダとして先に例示した各種のバインダと同じものを使用することができる。 As the binder relating to the negative electrode mixture layer, the same binders as those exemplified above as the binder relating to the positive electrode mixture layer can be used.
　負極合剤層に導電助剤を含有させる場合、その導電助剤には、正極合剤層に係る導電助剤として先に例示した各種の導電助剤と同じものを使用することができる。 When the negative electrode mixture layer contains a conductive additive, the same conductive assistants as those exemplified above as the conductive additive related to the positive electrode mixture layer can be used.
　負極は、例えば、負極活物質およびバインダ、更には必要に応じて導電助剤などを含有する負極合剤を、ＮＭＰや水などの溶剤に分散させてペースト状やスラリー状の正極合剤含有組成物を調製し（ただし、バインダは溶剤に溶解していてもよい）、これを集電体の片面または両面に塗布し、乾燥した後に、必要に応じてカレンダー処理を施し、更にこの負極を基材として、その負極合剤層上に、前記の方法で本発明の多孔質層を形成する工程を経て製造することができる。ただし、負極は、前記の方法で製造されたものに限定される訳ではなく、他の方法で製造したものであってもよい。 The negative electrode includes, for example, a negative electrode active material, a binder, and, if necessary, a negative electrode mixture containing a conductive auxiliary agent in a solvent such as NMP or water to disperse a paste or slurry-like positive electrode mixture. (However, the binder may be dissolved in a solvent.) This is applied to one or both sides of the current collector, dried, and then calendered as necessary. As a material, it can manufacture through the process of forming the porous layer of this invention on the negative mix layer by the said method. However, the negative electrode is not limited to those manufactured by the above method, and may be manufactured by other methods.
　負極の集電体には、例えば、銅、ステンレス鋼、ニッケル、チタンまたはそれらの合金などからなる箔、パンチドメタル、エキスパンドメタル、網などを用い得るが、通常、厚みが５～３０μｍの銅箔が好適に用いられる。 For the current collector of the negative electrode, for example, a foil made of copper, stainless steel, nickel, titanium, or an alloy thereof, a punched metal, an expanded metal, a net, or the like can be used. Usually, a copper having a thickness of 5 to 30 μm is used. A foil is preferably used.
　また、負極には、必要に応じて、非水電池内の他の部材と電気的に接続するためのリード体を、常法に従って形成してもよい。 In addition, a lead body for electrical connection with other members in the nonaqueous battery may be formed on the negative electrode according to a conventional method, if necessary.
　負極合剤層においては、例えば、負極活物質の含有量が７０～９９質量％であることが好ましく、バインダの含有量が１～３０質量％であることが好ましい。また、導電助剤を使用する場合には、負極合剤層における導電助剤の含有量は、１～２０質量％であることが好ましい。更に、負極合剤層の厚みは、集電体の片面あたり、１～１００μｍであることが好ましい。 In the negative electrode mixture layer, for example, the content of the negative electrode active material is preferably 70 to 99% by mass, and the content of the binder is preferably 1 to 30% by mass. In the case where a conductive assistant is used, the content of the conductive assistant in the negative electrode mixture layer is preferably 1 to 20% by mass. Further, the thickness of the negative electrode mixture layer is preferably 1 to 100 μm per side of the current collector.
　本発明の非水電池は、正極、負極、セパレータおよび非水電解質を有しており、セパレータが本発明のセパレータであるか、または正極、負極および非水電解質を有しており、正極および負極のうちの少なくとも一方が本発明の電極であればよく、その他の構成および構造については特に制限はなく、従来から知られているリチウム二次電池のなどの非水電池で採用されている各種構成および構造を適用することができる。 The nonaqueous battery of the present invention has a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte, and the separator is the separator of the present invention, or has a positive electrode, a negative electrode, and a nonaqueous electrolyte, and the positive electrode and the negative electrode It is sufficient that at least one of the electrodes is the electrode of the present invention, and there are no particular restrictions on the other configurations and structures, and various configurations employed in conventionally known non-aqueous batteries such as lithium secondary batteries And structure can be applied.
　本発明の非水電池において、本発明のセパレータを使用しない場合には、本発明の電極に係る多孔質層（本発明の多孔質層）がセパレータの役割を担うが、別途セパレータを使用してもよく、その場合のセパレータには、セパレータを構成するための前記多孔質樹脂フィルムを使用することができる。また、本発明の非水電池において、本発明の電極を正極に使用しない場合には、その正極には、本発明の多孔質層を有することを除いて本発明の電極と同じ構成の正極を使用することができる。更に、本発明の非水電池において、本発明の電極を負極に使用しない場合には、その正極には、本発明の多孔質層を有することを除いて本発明の電極と同じ構成の負極を使用することができる。 In the nonaqueous battery of the present invention, when the separator of the present invention is not used, the porous layer (the porous layer of the present invention) according to the electrode of the present invention plays the role of a separator, but a separate separator is used. The porous resin film for constituting the separator can be used as the separator in that case. In addition, in the nonaqueous battery of the present invention, when the electrode of the present invention is not used as a positive electrode, the positive electrode has the same configuration as the electrode of the present invention except that it has the porous layer of the present invention. Can be used. Furthermore, in the non-aqueous battery of the present invention, when the electrode of the present invention is not used as a negative electrode, the negative electrode having the same configuration as that of the electrode of the present invention is used except that the positive electrode has the porous layer of the present invention. Can be used.
　本発明の非水電池において、正極と負極とは、セパレータを介在させて積層するか、または、少なくとも一方の電極合剤層上に形成した多孔質層が間になるように積層して構成した積層体（積層電極体）や、この積層体を渦巻状に巻回した巻回体（巻回電極体）の形態で使用される。 In the nonaqueous battery of the present invention, the positive electrode and the negative electrode are laminated with a separator interposed therebetween, or are laminated so that a porous layer formed on at least one electrode mixture layer is interposed therebetween. It is used in the form of a laminated body (laminated electrode body) or a wound body (wound electrode body) obtained by winding this laminated body in a spiral shape.
　非水電池の非水電解質としては、上述したように、リチウム塩を有機溶媒に溶解した溶液（非水電解液）が用いられる。リチウム塩としては、溶媒中で解離してＬｉ＋イオンを形成し、電池として使用される電圧範囲で分解などの副反応を起こさないものであれば特に制限は無い。例えば、ＬｉＣｌＯ４、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６ などの無機リチウム塩；ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、Ｌｉ２Ｃ２Ｆ４（ＳＯ３）２、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＣｎＦ２ｎ＋１ＳＯ３（ｎ≧２）、ＬｉＮ（ＲｆＯＳＯ２）２〔ここでＲｆはフルオロアルキル基〕などの有機リチウム塩；などを用いることができる。 As the non-aqueous electrolyte of the non-aqueous battery, as described above, a solution (non-aqueous electrolyte) in which a lithium salt is dissolved in an organic solvent is used. The lithium salt is not particularly limited as long as it dissociates in a solvent to form Li + ions and does not cause a side reaction such as decomposition in a voltage range used as a battery. For example, inorganic lithium salts such as LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 ; LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ≧ 2), LiN (R f OSO 2 ) 2 [where R f is a fluoroalkyl group], etc .; Can be used.
　非水電解液に用いる有機溶媒としては、前記のリチウム塩を溶解し、電池として使用される電圧範囲で分解などの副反応を起こさないものであれば特に限定されない。例えば、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネート；ジメチルカーボネート、ジエチルカーボネート、メチルエチルカーボネートなどの鎖状カーボネート；プロピオン酸メチルなどの鎖状エステル；γ－ブチロラクトンといった環状エステル；ジメトキシエタン、ジエチルエーテル、１，３－ジオキソラン、ジグライム、トリグライム、テトラグライムなどの鎖状エーテル；ジオキサン、テトラヒドロフラン、２－メチルテトラヒドロフランなどの環状エーテル；アセトニトリル、プロピオニトリル、メトキシプロピオニトリルといったニトリル類；エチレングリコールサルファイトなどの亜硫酸エステル類；などが挙げられ、これらを１種単独で用いてもよいし、２種以上を併用しても構わない。なお、より良好な特性の電池とするためには、エチレンカーボネートと鎖状カーボネートの混合溶媒など、高い導電率を得ることができる組み合わせで用いることが望ましい。また、これらの非水電解液に安全性や充放電サイクル性、高温貯蔵性といった特性を向上させる目的で、ビニレンカーボネート類、１，３－プロパンサルトン、ジフェニルジスルフィド、シクロヘキシルベンゼン、ビフェニル、フルオロベンゼン、ｔ－ブチルベンゼンなどの添加剤を適宜加えることもできる。 The organic solvent used in the non-aqueous electrolyte is not particularly limited as long as it dissolves the lithium salt and does not cause side reactions such as decomposition in the voltage range used as a battery. For example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; chain esters such as methyl propionate; cyclic esters such as γ-butyrolactone; Chain ethers such as ethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme and tetraglyme; cyclic ethers such as dioxane, tetrahydrofuran and 2-methyltetrahydrofuran; nitriles such as acetonitrile, propionitrile and methoxypropionitrile; Sulfites such as ethylene glycol sulfite; and the like, and these may be used alone. , It may be used in combination of two or more thereof. In order to obtain a battery with better characteristics, it is desirable to use a combination that can obtain high conductivity, such as a mixed solvent of ethylene carbonate and chain carbonate. In addition, vinylene carbonates, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl, and fluorobenzene are used for the purpose of improving the safety, charge / discharge cycleability, and high-temperature storage properties of these non-aqueous electrolytes. Additives such as t-butylbenzene can also be added as appropriate.
　このリチウム塩の非水電解液中の濃度としては、０．５～１．５ｍｏｌ／ｌとすることが好ましく、０．９～１．２５ｍｏｌ／ｌとすることがより好ましい。 The concentration of this lithium salt in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / l, more preferably 0.9 to 1.25 mol / l.
　また、前記の有機溶媒の代わりに、エチル－メチルイミダゾリウムトリフルオロメチルスルホニウムイミド、へプチル－トリメチルアンモニウムトリフルオロメチルスルホニウムイミド、ピリジニウムトリフルオロメチルスルホニウムイミド、グアジニウムトリフルオロメチルスルホニウムイミドといった常温溶融塩を用いることもできる。 Also, instead of the organic solvent, melting at room temperature such as ethyl-methylimidazolium trifluoromethylsulfonium imide, heptyl-trimethylammonium trifluoromethylsulfonium imide, pyridinium trifluoromethylsulfonium imide, guanidinium trifluoromethylsulfonium imide A salt can also be used.
　更に、前記の非水電解液を含有してゲル化するような高分子材料を添加して、非水電解液をゲル状（ゲル状電解質）にして電池に用いてもよい。非水電解液をゲル状とするための高分子材料としては、ＰＶＤＦ、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体（ＰＶＤＦ－ＨＦＰ）、ＰＡＮ、ポリエチレンオキシド、ポリプロピレンオキシド、エチレンオキシド－プロピレンオキシド共重合体、主鎖または側鎖にエチレンオキシド鎖を有する架橋ポリマー、架橋したポリ（メタ）アクリル酸エステルなど、公知のゲル状電解質形成可能なホストポリマーが挙げられる。 Furthermore, a polymer material that contains the non-aqueous electrolyte and gels may be added to make the non-aqueous electrolyte into a gel (gel electrolyte) for use in a battery. Polymer materials for making non-aqueous electrolyte into gel include PVDF, vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), PAN, polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer And a known host polymer capable of forming a gel electrolyte, such as a crosslinked polymer having an ethylene oxide chain in the main chain or side chain, and a crosslinked poly (meth) acrylate.
　本発明の非水電池の形態としては、スチール缶やアルミニウム缶などを外装缶として使用した筒形（角筒形や円筒形など）などが挙げられる。また、金属を蒸着したラミネートフィルムを外装体としたソフトパッケージ電池とすることもできる。 Examples of the form of the non-aqueous battery of the present invention include a cylindrical shape (such as a rectangular tube shape or a cylindrical shape) using a steel can or an aluminum can as an outer can. Moreover, it can also be set as the soft package battery which used the laminated film which vapor-deposited the metal as an exterior body.
　以下、実施例に基づいて本発明を詳細に述べる。ただし、下記実施例は、本発明を制限するものではない。 Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.
実施例１
＜正極の作製＞
　正極活物質であるＬｉＣｏＯ２：９０質量部に、導電助剤であるカーボンブラック：５質量部を加えて混合し、この混合物にバインダであるＰＶＤＦ：５質量部をＮＭＰに溶解させた溶液を加えて混合して正極合剤含有スラリーとし、７０メッシュの網を通過させて粒径が大きいものを取り除いた。この正極合剤含有スラリーを、厚みが１５μｍのアルミニウム箔からなる正極集電体の両面に均一に塗布して乾燥し、その後ロールプレス機によって圧縮成形して総厚みを１０５μｍにした後、切断し、集電体の露出部にアルミニウム製のリード体を溶接して、帯状の正極を作製した。 Example 1
<Preparation of positive electrode>
LiCoO 2 as a positive electrode active material: 90 parts by mass, carbon black as a conductive auxiliary agent: 5 parts by mass are added and mixed, and a solution in which 5 parts by mass of PVDF as a binder is dissolved in NMP is added to this mixture. The mixture was mixed to obtain a positive electrode mixture-containing slurry, which was passed through a 70-mesh net to remove a large particle size. This positive electrode mixture-containing slurry is uniformly applied to both sides of a positive electrode current collector made of an aluminum foil having a thickness of 15 μm, dried, and then compression-molded by a roll press machine to a total thickness of 105 μm, followed by cutting. Then, an aluminum lead body was welded to the exposed portion of the current collector to produce a strip-like positive electrode.
＜負極の作製＞
　負極活物質である人造黒鉛：９５質量部と、バインダであるＰＶＤＦ：５質量部とを混合し、更にＮＭＰを加えて混合して負極合剤含有ペーストを調製した。この負極合剤含有ペーストを、厚みが１０μｍの銅箔からなる負極集電体の両面に均一に塗布して乾燥し、その後ロールプレス機によって圧縮成形して総厚みを１００μｍにした後、切断し、集電体の露出部にニッケル製のリード体を溶接して、帯状の負極を作製した。 <Production of negative electrode>
Artificial graphite as a negative electrode active material: 95 parts by mass and PVDF as a binder: 5 parts by mass were mixed, and NMP was further added and mixed to prepare a negative electrode mixture-containing paste. This negative electrode mixture-containing paste is uniformly coated on both sides of a negative electrode current collector made of copper foil having a thickness of 10 μm, dried, and then compression-molded by a roll press machine to a total thickness of 100 μm, followed by cutting. Then, a nickel lead body was welded to the exposed portion of the current collector to produce a strip-shaped negative electrode.
＜非水電解液の調製＞
　エチレンカーボネート、メチルエチルカーボネートおよびジエチルカーボネートの体積比１０：１０：３０の混合溶媒にＬｉＰＦ６を１．０ｍｏｌ／ｌの濃度で溶解させたものに、ビニレンカーボネートを、非水電解液の全量に対して２．５質量％となるように添加して、非水電解液を調製した。 <Preparation of non-aqueous electrolyte>
In a solvent mixture of ethylene carbonate, methyl ethyl carbonate and diethyl carbonate having a volume ratio of 10:10:30, LiPF 6 was dissolved at a concentration of 1.0 mol / l, and vinylene carbonate was added to the total amount of the non-aqueous electrolyte. The non-aqueous electrolyte was prepared by adding 2.5% by mass.
＜セパレータの作製＞
　耐熱温度が１５０℃以上の微粒子であるベーマイト粉末（板状、平均粒径：１μｍ、アスペクト比：１０、比表面積：８ｍ２／ｇ）：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で９０：１０、分子量：５０万）の５質量％濃度の水溶液：１６００ｇを加え、更に水を加えて均一に分散するまで室温で攪拌し、固形分濃度が３０質量％の多孔質層形成用スラリーを調製した。 <Preparation of separator>
Boehmite powder (plate shape, average particle size: 1 μm, aspect ratio: 10, specific surface area: 8 m 2 / g): 4000 g, fine particles having a heat-resistant temperature of 150 ° C. or higher, are added to water: 4000 g in four portions, A uniform slurry was prepared by stirring at 2800 rpm for 5 hours with a disper. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio 90:10, molecular weight: 500,000). Further, water was added and the mixture was stirred at room temperature until uniformly dispersed to prepare a slurry for forming a porous layer having a solid content concentration of 30% by mass.
　片面をコロナ放電処理したＰＥ製微多孔膜（厚み：１６μｍ、空孔率：４０％、ＰＥの融点：１３５℃）の処理面上に、前記の多孔質層形成用スラリーをマイクログラビアコーターによって塗布し、乾燥して多孔質層を形成することで、厚みが２０μｍのセパレータを得た。 The slurry for forming a porous layer is applied by a microgravure coater on a treated surface of a PE microporous membrane (thickness: 16 μm, porosity: 40%, PE melting point: 135 ° C.) subjected to corona discharge treatment on one side. And drying to form a porous layer, thereby obtaining a separator having a thickness of 20 μm.
＜電池の組み立て＞
　前記のようにして得たセパレータを、多孔質層が正極側に向くように前記正極と前記負極との間に介在させつつ重ね、渦巻状に巻回して巻回電極体を作製した。得られた巻回電極体を、径：１８ｍｍ、高さ：６５ｍｍの鉄製外装缶（電池ケース）に入れ、非水電解液を注入した後に封止を行って、図１に示す構造の非水二次電池を作製した。 <Battery assembly>
The separator obtained as described above was laminated while being interposed between the positive electrode and the negative electrode so that the porous layer was directed to the positive electrode side, and wound into a spiral shape to produce a wound electrode body. The obtained wound electrode body is put into an iron outer can (battery case) having a diameter of 18 mm and a height of 65 mm, and after sealing with a nonaqueous electrolyte, sealing is performed, and the nonaqueous water having the structure shown in FIG. A secondary battery was produced.
　ここで、図１に示す電池について説明すると、図１に示す非水二次電池では、正極１と負極２とがセパレータ３を介して渦巻状に巻回され、巻回電極体として非水電解液４と共に電池ケース５内に収容されている。なお、図１では、繁雑化を避けるため、正極１や負極２の作製にあたって使用した集電体などは図示しておらず、セパレータの各層も示していない。 Here, the battery shown in FIG. 1 will be described. In the nonaqueous secondary battery shown in FIG. 1, the positive electrode 1 and the negative electrode 2 are spirally wound via the separator 3, and nonaqueous electrolysis is used as a wound electrode body. It is accommodated in the battery case 5 together with the liquid 4. In FIG. 1, in order to avoid complication, the current collectors used for manufacturing the positive electrode 1 and the negative electrode 2 are not shown, and each layer of the separator is not shown.
　電池ケース５はステンレス鋼製で、その底部には前記巻回電極体の挿入に先立って、ＰＰからなる絶縁体６が配置されている。封口板７は、アルミニウム製で円板状をしていて、その中央部に薄肉部７ａが設けられ、かつ前記薄肉部７ａの周囲に電池内圧を防爆弁９に作用させるための圧力導入口７ｂとしての孔が設けられている。そして、この薄肉部７ａの上面に防爆弁９の突出部９ａが溶接され、溶接部分１１を構成している。なお、前記の封口板７に設けた薄肉部７ａや防爆弁９の突出部９ａなどは、図面上での理解がしやすいように、切断面のみを図示しており、切断面後方の輪郭は図示を省略している。また、封口板７の薄肉部７ａと防爆弁９の突出部９ａの溶接部分１１も、図面上での理解が容易なように、実際よりは誇張した状態に図示している。 The battery case 5 is made of stainless steel, and an insulator 6 made of PP is disposed at the bottom of the battery case 5 prior to insertion of the wound electrode body. The sealing plate 7 is made of aluminum and has a disk shape. A thin portion 7a is provided at the center of the sealing plate 7, and a pressure introduction port 7b for allowing the battery internal pressure to act on the explosion-proof valve 9 around the thin portion 7a. As a hole. And the protrusion part 9a of the explosion-proof valve 9 is welded to the upper surface of this thin part 7a, and the welding part 11 is comprised. The thin-walled portion 7a provided on the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 are shown only on the cut surface for easy understanding on the drawing, and the contour behind the cut surface is The illustration is omitted. In addition, the welded portion 11 of the thin-walled portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 is also illustrated in an exaggerated state so as to facilitate understanding on the drawing.
　端子板８は、圧延鋼製で表面にニッケルメッキが施され、周縁部が鍔状になった帽子状をしており、この端子板８にはガス排出口８ａが設けられている。防爆弁９は、アルミニウム製で円板状をしており、その中央部には発電要素側（図１では、下側）に先端部を有する突出部９ａが設けられ、かつ薄肉部９ｂが設けられ、前記突出部９ａの下面が、前記のように、封口板７の薄肉部７ａの上面に溶接され、溶接部分１１を構成している。絶縁パッキング１０は、ＰＰ製で環状をしており、封口板７の周縁部の上部に配置され、その上部に防爆弁９が配置していて、封口板７と防爆弁９とを絶縁するとともに、両者の間から非水電解液が漏れないように両者の間隙を封止している。環状ガスケット１２はＰＰ製で、リード体１３はアルミニウム製で、前記封口板７と正極１とを接続し、巻回電極体の上部には絶縁体１４が配置され、負極２と電池ケース５の底部とはニッケル製のリード体１５で接続されている。 The terminal plate 8 is made of rolled steel, has a nickel plating on the surface, and has a cap shape with a peripheral edge portion, and the terminal plate 8 is provided with a gas discharge port 8a. The explosion-proof valve 9 is made of aluminum and has a disk shape, and a central portion is provided with a protruding portion 9a having a tip portion on the power generation element side (lower side in FIG. 1) and a thin portion 9b. As described above, the lower surface of the protruding portion 9a is welded to the upper surface of the thin portion 7a of the sealing plate 7 to constitute the welded portion 11. The insulating packing 10 is made of PP and has an annular shape. The insulating packing 10 is arranged at the upper part of the peripheral edge of the sealing plate 7. The explosion-proof valve 9 is arranged at the upper part of the insulating packing 10 and insulates the sealing plate 7 and the explosion-proof valve 9. The gap between the two is sealed so that the non-aqueous electrolyte does not leak between the two. The annular gasket 12 is made of PP, the lead body 13 is made of aluminum, the sealing plate 7 and the positive electrode 1 are connected, an insulator 14 is disposed on the upper part of the wound electrode body, and the negative electrode 2 and the battery case 5 The bottom is connected by a lead body 15 made of nickel.
　この非水二次電池においては、封口板７の薄肉部７ａと防爆弁９の突出部９ａとが溶接部分１１で接触し、防爆弁９の周縁部と端子板８の周縁部とが接触し、正極１と封口板７とは正極側のリード体１３で接続されているので、通常の状態では、正極１と端子板８とはリード体１３、封口板７、防爆弁９およびそれらの溶接部分１１によって電気的接続が得られ、電路として正常に機能する。 In this non-aqueous secondary battery, the thin-walled portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 are in contact with each other at the welded portion 11, and the peripheral portion of the explosion-proof valve 9 and the peripheral portion of the terminal plate 8 are in contact. Since the positive electrode 1 and the sealing plate 7 are connected by the lead body 13 on the positive electrode side, in the normal state, the positive electrode 1 and the terminal plate 8 are connected to the lead body 13, the sealing plate 7, the explosion-proof valve 9 and their welding. The portion 11 provides an electrical connection and functions normally as an electrical circuit.
　そして、電池が高温に曝されるなど、電池に異常事態が起こり、電池内部にガスが発生して電池の内圧が上昇した場合には、その内圧上昇により、防爆弁９の中央部が内圧方向（図１では、上側の方向）に変形し、それに伴って溶接部分１１で一体化されている薄肉部７ａに剪断力が働いて該薄肉部７ａが破断するか、または防爆弁９の突出部９ａと封口板７の薄肉部７ａとの溶接部分１１が剥離した後、この防爆弁９に設けられている薄肉部９ｂが開裂してガスを端子板８のガス排出口８ａから電池外部に排出させて電池の破裂を防止することができるように設計されている。 When the battery is exposed to a high temperature and an abnormal situation occurs, gas is generated inside the battery and the internal pressure of the battery rises, the internal pressure rises and the central portion of the explosion-proof valve 9 is moved in the internal pressure direction. (The upper direction in FIG. 1) is deformed, and accordingly, the thin portion 7a integrated with the welded portion 11 is subjected to a shearing force to break the thin portion 7a, or the protruding portion of the explosion-proof valve 9 After the welded part 11 between 9a and the thin part 7a of the sealing plate 7 is peeled off, the thin part 9b provided in the explosion-proof valve 9 is cleaved and the gas is discharged from the gas outlet 8a of the terminal plate 8 to the outside of the battery. It is designed to prevent the battery from bursting.
　本実施例の非水二次電池は、４．２Ｖまで充電した場合（正極の電位がＬｉ基準で４．３Ｖ）の設計電気容量は、１４００ｍＡｈである（後記の全ての実施例および比較例の電池も同様である）。 The non-aqueous secondary battery of this example has a design electric capacity of 1400 mAh when charged to 4.2 V (the positive electrode potential is 4.3 V with respect to Li) (for all examples and comparative examples described later). The same applies to the battery).
実施例２
　実施例１で用いたものと同じベーマイト粉末：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で７０：３０、分子量：５０万）の５質量濃度の％水溶液：１６００ｇを加え、更に水を加えて均一に分散するまで室温で攪拌し、固形分濃度が３０質量％のスラリーを得た。このスラリーにフッ素系界面活性剤を水：１００質量部に対して０．１質量部となる量で添加し、均一になるまで攪拌して、多孔質層形成用スラリーを調製した。 Example 2
The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide, an organic binder, and sodium acrylate (copolymerization ratio 70:30 by mass ratio, molecular weight: 500,000). Further, water was added and the mixture was stirred at room temperature until it was uniformly dispersed to obtain a slurry having a solid content concentration of 30% by mass. To this slurry, a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass of water, and stirred until uniform to prepare a slurry for forming a porous layer.
　実施例１でセパレータの作製に用いたものと同じＰＥ製微多孔膜上にグラビアコーターを用いて前記の多孔質層形成用スラリーを塗布した後、乾燥することによって厚みが２０μｍのセパレータを得た。そして、前記のセパレータを用いた以外は、実施例１と同様にして非水二次電池を作製した。 A slurry having a thickness of 20 μm was obtained by applying the slurry for forming a porous layer using a gravure coater on the same microporous membrane made of PE as that used for producing the separator in Example 1, and then drying the slurry. . And the non-aqueous secondary battery was produced like Example 1 except having used the said separator.
実施例３
　実施例１で用いたものと同じベーマイト粉末：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で９０：１０、分子量：１００万）の５質量％濃度の水溶液：１６００ｇを加え、更に水を加えて均一に分散するまで室温で攪拌し、固形分濃度が３０質量％のスラリーを得た。このスラリーにフッ素系界面活性剤を水：１００質量部に対して０．１質量部となる量で添加し、均一になるまで攪拌して、多孔質層形成用スラリーを調製した。 Example 3
The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1600 g of a 5 mass% aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio 90:10 by mass ratio, molecular weight: 1 million). Further, water was added and the mixture was stirred at room temperature until it was uniformly dispersed to obtain a slurry having a solid content concentration of 30% by mass. To this slurry, a fluorosurfactant was added in an amount of 0.1 part by mass with respect to 100 parts by mass of water, and stirred until uniform to prepare a slurry for forming a porous layer.
　前記の多孔質層形成用スラリーを用いた以外は実施例２と同様にして厚みが２０μｍのセパレータを作製し、このセパレータを用いた以外は実施例１と同様にして非水二次電池を作製した。 A separator having a thickness of 20 μm was prepared in the same manner as in Example 2 except that the slurry for forming the porous layer was used, and a nonaqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used. did.
実施例４
　ＰＥ製微多孔膜に代えて、ＰＰ層とＰＥ層とを、ＰＰ／ＰＥ／ＰＰの順に３層積層した微多孔膜（厚み：１６μｍ、空孔率：４５％、各層の厚み；ＰＰ層：５μｍ／ＰＥ層：６μｍ／ＰＰ層：５μｍ）を用いた以外は、実施例３と同様にしてセパレータを作製した。そして、このセパレータを用いた以外は、実施例１と同様にして非水二次電池を作製した。 Example 4
Instead of the PE microporous membrane, a microporous membrane in which three layers of PP layer and PE layer are laminated in the order of PP / PE / PP (thickness: 16 μm, porosity: 45%, thickness of each layer; PP layer: A separator was prepared in the same manner as in Example 3 except that 5 μm / PE layer: 6 μm / PP layer: 5 μm) was used. And the non-aqueous secondary battery was produced like Example 1 except having used this separator.
実施例５
　実施例１で用いたものと同じベーマイト粉末：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、熱溶融性微粒子であるＰＥ微粒子（ＰＥの融点：１３５℃）の水分散体（固形分濃度４０質量％）：４０００ｇと、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で９０：１０、分子量：５０万）の５質量％濃度の水溶液：２１００ｇとを加え、更に水を固形分濃度が３０質量％になるように加えて、均一になるまで攪拌して、多孔質層形成用スラリーを得た。 Example 5
The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry, 4000 g of an aqueous dispersion (solid content concentration: 40% by mass) of PE fine particles (PE melting point: 135 ° C.), which are hot-melt fine particles, N-vinylacetamide, which is an organic binder, and sodium acrylate, 2100 g of an aqueous solution (copolymerization ratio is 90:10 by weight ratio, molecular weight: 500,000): 2100 g, and water is added so that the solid content concentration is 30% by mass. The mixture was stirred until it became uniform to obtain a slurry for forming a porous layer.
　ＰＥＴ製不織布（目付け８ｇ／ｍ２、厚み１６μｍ）に前記の多孔質層形成用スラリーをディップ塗布して、厚みが２０μｍの多孔質膜（多孔質層）を作製した。そして、この多孔質膜をセパレータとして用いた以外は、実施例１と同様にして非水二次電池を作製した。 The porous layer forming slurry was dip coated on a PET nonwoven fabric (weighing 8 g / m 2 , thickness 16 μm) to prepare a porous film (porous layer) having a thickness of 20 μm. A nonaqueous secondary battery was produced in the same manner as in Example 1 except that this porous membrane was used as a separator.
実施例６
　フィラーとして、アルミナ微粒子（平均粒径０.４μｍ、比表面積　７ｍ２／ｇ）を用い、アルミナ粉末４０００ｇを、水４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、熱溶融性微粒子であるＰＥ微粒子（ＰＥの融点１３５℃）の水分散体（固形分濃度：４０質量％）：４０００ｇと、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で９０：１０、分子量：５０万）の５質量％濃度の水溶液：１６００ｇとを加え、更に水を固形分濃度が３０質量％になるように加えて、均一になるまで攪拌して、多孔質層形成用スラリーを調製した。 Example 6
Alumina fine particles (average particle size: 0.4 μm, specific surface area: 7 m 2 / g) are used as fillers, and 4000 g of alumina powder is added to 4000 g of water in four portions, and stirred with a disper at 2800 rpm for 5 hours to form a uniform slurry. Was prepared. To this slurry, an aqueous dispersion (solid content concentration: 40% by mass) of PE fine particles (PE melting point: 135 ° C.) as heat-melting fine particles: 4000 g, an organic binder N-vinylacetamide, and an acrylic acid Na salt A copolymer (copolymerization ratio is 90:10 by mass ratio, molecular weight: 500,000) and a 5 mass% aqueous solution: 1600 g is added, and water is further added so that the solid content concentration becomes 30 mass%. The mixture was stirred until it became uniform to prepare a slurry for forming a porous layer.
　前記の多孔質層形成用スラリーを、実施例１で作製したものと同じ負極の両側の負極合剤層上にグラビアコーターを用いて塗布して乾燥し、負極の片面あたりの厚みが２０μｍの多孔質層を形成した。 The slurry for forming the porous layer is applied on the negative electrode mixture layer on both sides of the same negative electrode as that prepared in Example 1 using a gravure coater and dried, and a porous material having a thickness of 20 μm on one side of the negative electrode. A quality layer was formed.
　実施例１で作製したものと同じ正極と前記の負極とを使用し、セパレータを使用しなかった以外は実施例１と同様にして巻回電極体を作製し、この巻回電極体を用いた以外は実施例１と同様にして非水二次電池を作製した。 A wound electrode body was prepared in the same manner as in Example 1 except that the same positive electrode as that prepared in Example 1 and the above-described negative electrode were used and a separator was not used, and this wound electrode body was used. A nonaqueous secondary battery was produced in the same manner as Example 1 except for the above.
実施例７
　実施例６で調製したものと同じ多孔質層形成用スラリーを、実施例１で作製したものと同じ負極の両側の負極合剤層上にグラビアコーターを用いて塗布して乾燥し、負極の片面あたりの厚みが１０μｍの多孔質層を形成した。また、実施例６で調製したものと同じ多孔質層形成用スラリーを、実施例１で作製したものと同じ正極の両側の正極合剤層上にグラビアコーターを用いて塗布して乾燥し、正極の片面あたりの厚みが１０μｍの多孔質層を形成した。 Example 7
The same slurry for forming a porous layer as that prepared in Example 6 was applied on the negative electrode mixture layer on both sides of the same negative electrode as that prepared in Example 1 using a gravure coater and dried. A porous layer having a thickness of 10 μm was formed. Also, the same slurry for forming a porous layer as that prepared in Example 6 was applied on the positive electrode mixture layer on both sides of the same positive electrode as that prepared in Example 1 using a gravure coater and dried. A porous layer having a thickness of 10 μm per side was formed.
　前記の負極と前記の正極とを用いた以外は実施例６と同様して巻回電極体を作製し、この巻回電極体を用いた以外は実施例１と同様にして非水二次電池を作製した。 A wound electrode body was prepared in the same manner as in Example 6 except that the negative electrode and the positive electrode were used, and a non-aqueous secondary battery was performed in the same manner as in Example 1 except that this wound electrode body was used. Was made.
比較例１
　実施例１で用いたものと同じベーマイト粉末：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーに、有機バインダであるポリＮ－ビニルアセトアミド（Ｎ－ビニルアセトアミドの単独重合体、分子量１００万）の５質量％濃度の水溶液：１２００ｇを加え、更に水を加えて均一に分散するまで室温で攪拌し、固形分濃度が３０質量％の多孔質層形成用スラリーを調製した。そして、この多孔質層形成用スラリーを用いた以外は実施例１と同様にしてセパレータを作製し、このセパレータを用いた以外は実施例１と同様にして非水二次電池を作製した。 Comparative Example 1
The same boehmite powder: 4000 g used in Example 1 was added to 4000 g of water in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry was added 1200 g of a 5 mass% aqueous solution of poly N-vinylacetamide (a homopolymer of N-vinylacetamide, molecular weight 1 million) as an organic binder, and water was added until room temperature until evenly dispersed. And a slurry for forming a porous layer having a solid content concentration of 30% by mass was prepared. A separator was prepared in the same manner as in Example 1 except that this porous layer forming slurry was used, and a non-aqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used.
比較例２
　比較例１で用いたものと同じベーマイト粒子：４０００ｇを、水：４０００ｇに４回に分けて加え、ディスパーにより２８００ｒｐｍで５時間攪拌して均一なスラリーを調製した。このスラリーを、有機バインダであるＮ－ビニルアセトアミドとアクリル酸Ｎａ塩との共重合体（共重合比が質量比で４０：６０、分子量：５０万）の５質量％濃度の水溶液：１２００ｇを加え、均一に分散するまで室温で攪拌して、多孔質層形成用スラリーを調製した。そして、この多孔質層形成用スラリーを用いた以外は実施例１と同様にしてセパレータを作製し、このセパレータを用いた以外は実施例１と同様にして非水二次電池を作製した。 Comparative Example 2
The same boehmite particles: 4000 g as used in Comparative Example 1 were added to water: 4000 g in four portions, and the mixture was stirred with a disper at 2800 rpm for 5 hours to prepare a uniform slurry. To this slurry, 1200 g of a 5% by weight aqueous solution of a copolymer of N-vinylacetamide as an organic binder and sodium acrylate (copolymerization ratio is 40:60, molecular weight: 500,000) is added. The mixture was stirred at room temperature until it was uniformly dispersed to prepare a slurry for forming a porous layer. A separator was prepared in the same manner as in Example 1 except that this porous layer forming slurry was used, and a non-aqueous secondary battery was prepared in the same manner as in Example 1 except that this separator was used.
　実施例１～４および比較例１、２の非水二次電池に使用したセパレータについて、前記の方法によって多孔質層と多孔質樹脂フィルムとの間の１８０°の剥離強度を測定した。 For the separators used in the nonaqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2, the 180 ° peel strength between the porous layer and the porous resin film was measured by the method described above.
　また、実施例１～４および比較例１、２の非水二次電池に使用したセパレータ、実施例５の非水二次電池にセパレータとして使用した多孔質膜（多孔質層）、並びに実施例６、７の非水二次電池に使用した多孔質層について、非水電解液溶媒中での熱収縮率測定を行った。 Also, separators used in the non-aqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2, porous membranes (porous layers) used as separators in the non-aqueous secondary battery of Example 5, and Examples About the porous layer used for the non-aqueous secondary battery of 6 and 7, the thermal contraction rate measurement in a non-aqueous electrolyte solvent was performed.
　実施例１～４および比較例１、２の非水二次電池に係るセパレータについては、これらのＭＤ方向、ＴＤ方向をそれぞれ５ｃｍ、１０ｃｍとした短冊状のサンプル片を切り取った。ここで、ＭＤ方向とは多孔質樹脂フィルム作製の際の機械方向であり、ＴＤ方向はそれに垂直な方向である。このサンプル片と非水電解液溶媒（エチレンカーボネートとジエチルカーボネートとの体積比１：１の混合溶媒）とを耐圧耐熱性容器に入れ、この容器を１５０℃の恒温槽に入れて１時間後に取り出し、更に耐圧耐熱性容器からサンプル片を取り出して、ＭＤ方向およびＴＤ方向の長さを測定することで、それぞれの方向の熱収縮率を測定し、ＭＤ方向の熱収縮率およびＴＤ方向の熱収縮率のうちのより大きい方の値を、セパレータの熱収縮率とした。 For the separators related to the non-aqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2, strip-shaped sample pieces having a MD direction and a TD direction of 5 cm and 10 cm, respectively, were cut out. Here, the MD direction is the machine direction during the production of the porous resin film, and the TD direction is a direction perpendicular thereto. This sample piece and a non-aqueous electrolyte solvent (a mixed solvent of ethylene carbonate and diethyl carbonate in a volume ratio of 1: 1) are placed in a pressure and heat resistant container, and the container is placed in a thermostatic bath at 150 ° C. and taken out after 1 hour. Further, the sample pieces are taken out from the pressure and heat resistant container, and the lengths in the MD direction and the TD direction are measured to measure the heat shrinkage rates in the respective directions, and the heat shrinkage rates in the MD direction and the heat shrinkage in the TD direction. The larger value of the rates was taken as the thermal shrinkage rate of the separator.
　また、実施例５の非水二次電池に係る多孔質膜については、任意の方向で５ｃｍ×１０ｃｍとした短冊状のサンプル片を作製した以外は、実施例１の電池に係るセパレータなどと同じ方法で熱収縮率を測定した。更に、実施例６、７の非水二次電池に係る多孔質層については、電極と一体化した状態で５ｃｍ×１０ｃｍの短冊状のサンプル片を作製した以外は、実施例１の電池に係るセパレータなどと同じ方法で熱収縮率を測定した。なお、実施例７の非水二次電池に係る多孔質層については、正極表面に形成したもの、および負極表面に形成したもののうちのより大きい値の方を、その熱収縮率とした。 The porous membrane according to the non-aqueous secondary battery of Example 5 is the same as the separator according to the battery of Example 1 except that a strip-shaped sample piece having a size of 5 cm × 10 cm in any direction was produced. The heat shrinkage rate was measured by the method. Furthermore, the porous layer according to the non-aqueous secondary battery of Examples 6 and 7 is related to the battery of Example 1 except that a strip-shaped sample piece of 5 cm × 10 cm is produced in an integrated state with the electrode. The thermal shrinkage rate was measured by the same method as for a separator. In addition, about the porous layer which concerns on the non-aqueous secondary battery of Example 7, the larger one of what was formed in the positive electrode surface and what was formed in the negative electrode surface was made into the thermal contraction rate.
　また、実施例１～４および比較例１、２の非水二次電池に係るセパレータ、並びに実施例５の非水二次電池に係る多孔質膜について、前記の方法で水分量を測定した。 Further, the moisture content of the separators according to the non-aqueous secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2 and the porous membrane according to the non-aqueous secondary battery of Example 5 was measured by the above method.
　前記の各評価結果を表１に示す。なお、表１では、セパレータにおける多孔質層と多孔質樹脂フィルムとの間の１８０°の剥離強度を、単に「剥離強度」と記載し、セパレータまたは多孔質層の非水電解液溶媒中における熱収縮率を、単に「熱収縮率」と記載する。 Table 1 shows the evaluation results. In Table 1, the 180 ° peel strength between the porous layer and the porous resin film in the separator is simply referred to as “peel strength”, and the heat in the nonaqueous electrolyte solvent of the separator or porous layer is described. The shrinkage rate is simply referred to as “thermal shrinkage rate”.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表１に示す通り、実施例１～７の非水二次電池に使用したセパレータまたは多孔質層は、非水電解液溶媒中、１５０℃での熱収縮率が小さかった。すなわち、これらのセパレータや多孔質層は、電池内において非水電解液溶媒の共存下で高温に曝されても収縮し難いことから、安全性に優れた非水二次電池を構成し得るといえる。なお、実施例１～４の非水二次電池に係るセパレータにおける多孔質層と多孔質樹脂フィルムとの間の１８０°の剥離強度の測定結果から、実施例１～７の非水二次電池に使用したセパレータまたは多孔質層で使用した有機バインダは、特定の共重合組成を有しているために、高い接着力を有していることが分かるが、更に前記の熱収縮率の測定結果から、非水電解液溶媒中で高温に曝されても、その優れた接着力が良好に維持できていることも分かる。 As shown in Table 1, the separators or porous layers used in the nonaqueous secondary batteries of Examples 1 to 7 had a small heat shrinkage rate at 150 ° C. in a nonaqueous electrolyte solvent. That is, since these separators and porous layers are unlikely to shrink even when exposed to high temperatures in the presence of a non-aqueous electrolyte solvent in the battery, it is possible to constitute a non-aqueous secondary battery with excellent safety. I can say that. From the measurement results of the 180 ° peel strength between the porous layer and the porous resin film in the separators according to the nonaqueous secondary batteries of Examples 1 to 4, the nonaqueous secondary batteries of Examples 1 to 7 were used. It can be seen that the organic binder used in the separator or porous layer used in the above has a specific copolymer composition, and thus has a high adhesive force. Thus, it can be seen that even when exposed to a high temperature in a non-aqueous electrolyte solvent, the excellent adhesive force can be maintained well.
　更に、実施例および比較例の非水二次電池について、以下の方法で充放電特性を評価した。まず、各電池について、０．２Ｃの電流値で電池電圧が４．２Ｖになるまで定電流充電を行い、次いで、４．２Ｖでの定電圧充電を行う定電流－定電圧充電を行った。充電終了までの総充電時間は１５時間とした。そして、そのときの充電容量を測定した。次に、充電後の各電池について、０．２Ｃの放電電流で電池電圧が３．０Ｖになるまで放電を行って放電容量を測定した。そして、各電池について、充電容量に対する放電容量の割合を百分率で表して、充電効率を求めた。 Furthermore, charge / discharge characteristics of the non-aqueous secondary batteries of Examples and Comparative Examples were evaluated by the following method. First, for each battery, constant current charging was performed until the battery voltage reached 4.2 V at a current value of 0.2 C, and then constant current-constant voltage charging for performing constant voltage charging at 4.2 V was performed. The total charging time until the end of charging was 15 hours. And the charge capacity at that time was measured. Next, each battery after charging was discharged at a discharge current of 0.2 C until the battery voltage reached 3.0 V, and the discharge capacity was measured. And about each battery, the ratio of the discharge capacity with respect to charge capacity was represented by the percentage, and charging efficiency was calculated | required.
　その結果、実施例１～７および比較例１の電池では、充電効率がほぼ１００％となり、電池として良好に作動することが確認できた。これに対し、比較例２の電池は、セパレータに係る多孔質層の有機バインダに、共重合組成が不適なものを使用したが、充電効率が低く、前記有機バインダの使用によってセパレータの水分量が多くなったことによるガス発生が顕著に認められた。 As a result, in the batteries of Examples 1 to 7 and Comparative Example 1, the charging efficiency was almost 100%, and it was confirmed that the battery operated well. On the other hand, in the battery of Comparative Example 2, an organic binder having an inappropriate copolymer composition was used as the organic binder of the porous layer related to the separator, but the charging efficiency was low, and the moisture content of the separator was reduced by using the organic binder. Gas generation due to the increase was noticeable.
　本発明は、その趣旨を逸脱しない範囲で、前記以外の形態としても実施が可能である。本出願に開示された実施形態は一例であって、本発明は、これらの実施形態には限定されない。本発明の範囲は、前記の明細書の記載よりも、添付されている請求の範囲の記載を優先して解釈され、請求の範囲と均等の範囲内での全ての変更は、請求の範囲に含まれる。 The present invention can be implemented in other forms as long as it does not depart from the spirit of the present invention. The embodiments disclosed in the present application are examples, and the present invention is not limited to these embodiments. The scope of the present invention is construed in preference to the description of the appended claims rather than the description of the above specification, and all modifications within the scope equivalent to the claims are construed in the scope of the claims. included.
　本発明の非水電池は、従来から知られているリチウム二次電池などの非水二次電池や、非水一次電池と同じ用途に適用することができる。 The nonaqueous battery of the present invention can be applied to the same uses as conventionally known nonaqueous secondary batteries such as lithium secondary batteries and nonaqueous primary batteries.
　１　正極
　２　負極
　３　セパレータ
　４　非水電解質 1 Positive electrode 2 Negative electrode 3 Separator 4 Nonaqueous electrolyte

Claims (12)

  1. 　耐熱温度が１５０℃以上の微粒子と有機バインダとを含む非水電池用多孔質層であって、
    　前記有機バインダとして、下記一般式（１）で表されるＮ－ビニルカルボン酸アミドと下記一般式（２）で表される不飽和カルボン酸系モノマーとの共重合体を含み、
    　前記共重合体における前記Ｎ－ビニルカルボン酸アミドと前記不飽和カルボン酸系モノマーとの共重合比が、質量比で５０：５０～９５：５であることを特徴とする非水電池用多孔質層。
    Figure JPOXMLDOC01-appb-C000001
     〔前記一般式（１）中、Ｒ１およびＲ２は、それぞれ独立に水素原子またはメチル基を、Ｒ３は水素原子または炭素数１～５のアルキル基を表す〕
    Figure JPOXMLDOC01-appb-C000002
     〔前記一般式（２）中、Ｒ４は水素原子、メチル基または－ＣＯＯＭ２を、Ｒ５は水素原子、メチル基または－ＣＯＯＭ３を、Ｍ１、Ｍ２およびＭ３は、それぞれ独立に水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基または有機アミノ基を表し、ｎは０または１である〕     A porous layer for a non-aqueous battery comprising fine particles having an heat resistant temperature of 150 ° C. or higher and an organic binder,
    Examples of the organic binder include a copolymer of an N-vinylcarboxylic acid amide represented by the following general formula (1) and an unsaturated carboxylic acid monomer represented by the following general formula (2):
    The non-aqueous battery porous material, wherein a copolymerization ratio of the N-vinylcarboxylic acid amide and the unsaturated carboxylic acid monomer in the copolymer is 50:50 to 95: 5 by mass ratio layer.
    Figure JPOXMLDOC01-appb-C000001
     [In the general formula (1), R 1 and R 2 each independently represent a hydrogen atom or a methyl group, and R 3 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms]
    Figure JPOXMLDOC01-appb-C000002
     [In the general formula (2), R 4 represents a hydrogen atom, a methyl group or —COOM 2 , R 5 represents a hydrogen atom, a methyl group or —COOM 3 , and M 1 , M 2 and M 3 each independently represent A hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group or an organic amino group, and n is 0 or 1)
  2. 　前記一般式（１）で表されるＮ－ビニルカルボン酸アミドが、Ｎ－ビニルアセトアミドである請求項１に記載の非水電池用多孔質層。 The porous layer for a non-aqueous battery according to claim 1, wherein the N-vinylcarboxylic amide represented by the general formula (1) is N-vinylacetamide.
  3. 　前記一般式（２）で表される不飽和カルボン酸系モノマーが、アクリル酸、メタクリル酸、アクリル酸塩およびメタクリル酸塩よりなる群から選択される少なくとも１種である請求項１または２に記載の非水電池用多孔質層。 The unsaturated carboxylic acid monomer represented by the general formula (2) is at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylate, and methacrylate. Porous layer for non-aqueous battery.
  4. 　前記一般式（２）で表される不飽和カルボン酸系モノマーが、アクリル酸のアルカリ金属塩またはメタクリル酸アルカリ金属塩である請求項３に記載の非水電池用多孔質層。 The porous layer for a nonaqueous battery according to claim 3, wherein the unsaturated carboxylic acid monomer represented by the general formula (2) is an alkali metal salt of acrylic acid or an alkali metal methacrylate.
  5. 　前記共重合体の分子量が、３０，０００～５，０００，０００である請求項１～４のいずれかに記載の非水電池用多孔質層。 The porous layer for a non-aqueous battery according to any one of claims 1 to 4, wherein the copolymer has a molecular weight of 30,000 to 5,000,000.
  6. 　前記微粒子が、酸化物または水酸化物の微粒子である請求項１～５のいずれかに記載の非水電池用多孔質層。 The porous layer for a non-aqueous battery according to any one of claims 1 to 5, wherein the fine particles are fine particles of oxide or hydroxide.
  7. 　前記有機バインダの含有量が、０．５～１０質量％である請求項１～６のいずれかに記載の非水電池用多孔質層。 The porous layer for a non-aqueous battery according to any one of claims 1 to 6, wherein the content of the organic binder is 0.5 to 10% by mass.
  8. 　請求項１～７のいずれかに記載の非水電池用多孔質層を、多孔質樹脂フィルム上に形成したことを特徴とする非水電池用セパレータ。 A separator for a non-aqueous battery, wherein the porous layer for a non-aqueous battery according to any one of claims 1 to 7 is formed on a porous resin film.
  9. 　前記多孔質樹脂フィルムが、ポリオレフィン微多孔膜である請求項８に記載の非水電池用セパレータ。 The separator for a non-aqueous battery according to claim 8, wherein the porous resin film is a polyolefin microporous film.
  10. 　請求項１～７のいずれかに記載の非水電池用多孔質層を、電極合剤層上に形成したことを特徴とする非水電池用電極。 A nonaqueous battery electrode, wherein the nonaqueous battery porous layer according to any one of claims 1 to 7 is formed on an electrode mixture layer.
  11. 　正極、負極、セパレータおよび非水電解質を有しており、前記セパレータが請求項８または９に記載の非水電池用セパレータであることを特徴とする非水電池。 A non-aqueous battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, wherein the separator is the separator for a non-aqueous battery according to claim 8 or 9.
  12. 　正極、負極、および非水電解質を有しており、前記正極および前記負極のうちの少なくとも一方が、請求項１０に記載の非水電池用電極であることを特徴とする非水電池。 A nonaqueous battery comprising a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein at least one of the positive electrode and the negative electrode is the electrode for a nonaqueous battery according to claim 10.
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