WO2014103792A1 - Suspension épaisse de film poreux de séparateur de batterie rechargeable, film poreux de séparateur de batterie rechargeable, procédé de production associé, séparateur de batterie rechargeable et batterie rechargeable - Google Patents

Suspension épaisse de film poreux de séparateur de batterie rechargeable, film poreux de séparateur de batterie rechargeable, procédé de production associé, séparateur de batterie rechargeable et batterie rechargeable Download PDF

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Publication number
WO2014103792A1
WO2014103792A1 PCT/JP2013/083716 JP2013083716W WO2014103792A1 WO 2014103792 A1 WO2014103792 A1 WO 2014103792A1 JP 2013083716 W JP2013083716 W JP 2013083716W WO 2014103792 A1 WO2014103792 A1 WO 2014103792A1
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porous membrane
binder
secondary battery
porous
porous film
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PCT/JP2013/083716
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English (en)
Japanese (ja)
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金田　拓也
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日本ゼオン株式会社
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Priority to JP2014554337A priority Critical patent/JP6287862B2/ja
Publication of WO2014103792A1 publication Critical patent/WO2014103792A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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 slurry for a porous film of a secondary battery separator, a porous film for a secondary battery separator and a method for producing the same, a separator for a secondary battery, and a secondary battery.
  • a separator In secondary batteries, a separator is generally used to prevent a short circuit between the positive electrode and the negative electrode.
  • the separator may affect the performance of the secondary battery such as safety and battery characteristics. For this reason, various studies have been made on the separator (see Patent Documents 1 and 2).
  • JP 2007-294437 A Japanese Patent Laid-Open No. 2005-056800
  • the separator usually has an organic separator layer.
  • a porous film may be provided on the organic separator layer as necessary.
  • the present invention was devised in view of the above-described problems, and is a secondary battery excellent in all of safety, high-temperature cycle characteristics, and rate characteristics, and in any of such safety, high-temperature cycle characteristics, and rate characteristics.
  • Another object of the present invention is to provide a slurry for a porous membrane of a secondary battery separator, a porous membrane for a secondary battery separator and a method for producing the same, and a separator for a secondary battery that can realize a secondary battery that is also excellent.
  • the present inventor is a slurry for a porous film containing non-conductive particles, a binder for a porous film, and a medium.
  • Secondary battery separator that can realize a secondary battery that is excellent in safety, high-temperature cycle characteristics, and rate characteristics by appropriately combining particulate or non-particulate binders with different degrees of swelling with respect to the electrolyte
  • the present inventors have found that a porous film can be obtained and completed the present invention. That is, the present invention is as follows.
  • the porous membrane binder is A porous membrane binder A that is particulate and can have a degree of swelling with respect to the non-aqueous electrolyte after formation of the porous membrane of less than 10 times; A porous membrane binder B that is particulate and can have a degree of swelling with respect to the non-aqueous electrolyte after formation of the porous membrane of 10 to 50 times; and A slurry for a porous membrane of a secondary battery separator, comprising a porous membrane binder C that is non-particulate and has a degree of swelling with respect to the non-aqueous electrolyte after formation of the porous membrane of less than 5 times.
  • a porous membrane for a secondary battery separator comprising non-conductive particles and a binder for a porous membrane
  • the porous membrane binder is A porous membrane binder A that is particulate and has a degree of swelling with respect to the non-aqueous electrolyte of less than 10 times;
  • a porous membrane binder B which is in the form of particles and has a swelling degree with respect to the non-aqueous electrolyte of 10 to 50 times;
  • a porous membrane for a secondary battery separator comprising a porous membrane binder C that is non-particulate and has a degree of swelling with respect to a non-aqueous electrolyte of less than 5 times.
  • a separator for a secondary battery comprising: an organic separator layer; and a porous film for a secondary battery separator according to [4] or [5] formed on the organic separator layer.
  • a secondary battery comprising a positive electrode, a negative electrode, the secondary battery separator according to [7], and an electrolytic solution.
  • a porous membrane for a secondary battery separator capable of realizing a secondary battery excellent in all of safety, high temperature cycle characteristics, and rate characteristics can be obtained.
  • a secondary battery excellent in safety, high temperature cycle characteristics and rate characteristics can be obtained.
  • a porous membrane for a secondary battery separator capable of realizing a secondary battery excellent in all of safety, high temperature cycle characteristics and rate characteristics can be obtained.
  • a secondary battery excellent in all of safety, high temperature cycle characteristics and rate characteristics can be obtained.
  • the secondary battery of the present invention is excellent in all of safety, high-temperature cycle characteristics, and rate characteristics.
  • FIG. 1 is an enlarged cross-sectional view schematically showing the vicinity of the surface of a porous membrane that is not wetted with a non-aqueous electrolyte.
  • FIG. 2 is an enlarged cross-sectional view schematically showing the vicinity of the surface of the porous membrane wet with the nonaqueous electrolytic solution.
  • (meth) acrylic acid represents acrylic acid or methacrylic acid.
  • (meth) acrylate represents an acrylate or a methacrylate.
  • (meth) acrylonitrile represents acrylonitrile or methacrylonitrile.
  • a certain substance is water-soluble when an insoluble content is less than 0.5% by weight when 0.5 g of the substance is dissolved in 100 g of water at 25 ° C.
  • a certain substance is water-insoluble means that an insoluble content is 90% by weight or more when 0.5 g of the substance is dissolved in 100 g of water at 25 ° C.
  • the proportion of the structural unit formed by polymerizing a certain monomer in the polymer is usually that unless otherwise specified. This coincides with the ratio (preparation ratio) of the certain monomer in the total monomers used for polymerization of the polymer.
  • the slurry for porous film of the present invention is a fluid composition containing non-conductive particles, a binder for porous film, and a medium.
  • the porous membrane binder includes a porous membrane binder A, a porous membrane binder B, and a porous membrane binder C.
  • Non-conductive particles As the non-conductive particles, inorganic particles or organic particles may be used.
  • the inorganic particles are usually excellent in dispersion stability in the medium, hardly settled in the slurry for the porous membrane, and can maintain a uniform slurry state for a long time. Moreover, when inorganic particles are used, the heat resistance of a porous membrane for a secondary battery separator (hereinafter, the porous membrane for a secondary battery separator may be referred to as “porous membrane” as appropriate) can be increased.
  • an electrochemically stable material is preferable.
  • inorganic materials for non-conductive particles include aluminum oxide (alumina), aluminum oxide hydrate (boehmite (AlOOH), gibbsite (Al (OH) 3 ), silicon oxide, Oxide particles such as magnesium oxide (magnesia), magnesium hydroxide, calcium oxide, titanium oxide (titania), BaTiO 3 , ZrO, alumina-silica composite oxide; nitride particles such as aluminum nitride and boron nitride; silicon, diamond And the like; Covalent crystal particles such as barium sulfate, calcium fluoride, barium fluoride, and the like; Clay fine particles such as talc and montmorillonite;
  • oxide particles are preferable from the viewpoints of stability in an electrolytic solution and potential stability, and titanium oxide and aluminum oxide are particularly preferable from the viewpoint of low water absorption and excellent heat resistance (for example, resistance to high temperature of 180 ° C. or higher).
  • Aluminum oxide hydrate, magnesium oxide and magnesium hydroxide are more preferable, aluminum oxide, aluminum oxide hydrate, magnesium oxide and magnesium hydroxide are more preferable, and aluminum oxide is particularly preferable.
  • Polymer particles are usually used as the organic particles.
  • the organic particles can control the affinity for water by adjusting the type and amount of the functional group on the surface of the organic particles, and thus can control the amount of water contained in the porous film.
  • Organic particles are excellent in that they usually have less metal ion elution.
  • the organic material for the nonconductive particles include various polymer compounds such as polystyrene, polyethylene, polyimide, melamine resin, and phenol resin.
  • the polymer compound forming the particles may be used, for example, as a mixture, a modified product, a derivative, a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer, a crosslinked product, or the like.
  • the organic particles may be formed of a mixture of two or more polymer compounds.
  • the glass transition temperature may not be present, but when the polymer compound forming the organic particles has a glass transition temperature, the glass transition temperature is usually 150 ° C. or higher. Preferably it is 200 degreeC or more, More preferably, it is 250 degreeC or more, and is 500 degrees C or less normally.
  • Non-conductive particles may be subjected to, for example, element substitution, surface treatment, solid solution, and the like as necessary. Further, the non-conductive particles may include one kind of the above materials alone in one particle, or may contain two or more kinds in combination at an arbitrary ratio. . Further, the non-conductive particles may be used in combination of two or more kinds of particles formed of different materials.
  • Examples of the shape of the nonconductive particles include a spherical shape, an elliptical spherical shape, a polygonal shape, a tetrapod (registered trademark) shape, a plate shape, and a scale shape.
  • tetrapod (registered trademark) plate, and scale are preferred from the viewpoint of increasing the porosity of the porous membrane and suppressing the decrease in ion conductivity due to the separator for secondary batteries.
  • the number average particle diameter of the non-conductive particles is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, preferably 5 ⁇ m or less, more preferably 2 ⁇ m or less, and particularly preferably 1 ⁇ m or less.
  • the number average particle size is a particle size-number integrated distribution measured by using a laser diffraction / scattering particle size distribution measuring apparatus (for example, “LS230” manufactured by Beckman Coulter, Inc.). Is the particle diameter.
  • the BET specific surface area of the non-conductive particles is, for example, preferably 0.9 m 2 / g or more, more preferably 1.5 m 2 / g or more. Further, from the viewpoint of suppressing aggregation of non-conductive particles and optimizing the fluidity of the slurry for the porous membrane, the BET specific surface area is preferably not too large, for example, 150 m 2 / g or less.
  • the binder A for porous films is a particulate binder. Therefore, the particles of the binder A for the porous film are dispersed in the medium in the slurry for the porous film.
  • the porous membrane binder A is usually formed of a material insoluble in the medium. Therefore, for example, when water is used as the medium, the porous membrane binder A is preferably formed of a water-insoluble material.
  • the binder A for porous membranes can have a degree of swelling with respect to the nonaqueous electrolytic solution after the porous membrane formation is usually less than 10 times, preferably less than 7 times, more preferably less than 5 times.
  • the degree of swelling of the binder A for porous membranes with respect to the non-aqueous electrolyte after the formation of the porous membrane is usually less than 10 times, preferably less than 7 times, more preferably less than 5 times.
  • the binding property of the binder A for porous membranes can be increased. Therefore, it is possible to increase the binding property of the porous membrane binder A to the non-conductive particles in the porous membrane or to increase the binding property between the porous membrane and the organic separator layer.
  • the safety of the secondary battery can be improved by increasing the mechanical strength of the separator.
  • the lower limit value of the degree of swelling of the porous membrane binder A with respect to the nonaqueous electrolytic solution after the formation of the porous membrane is not particularly limited, but can usually be 1 or more times.
  • the “swelling degree after formation of the porous film” of the binder refers to the degree of swelling of the binder in the state after forming the porous film, not in the state of being dissolved or dispersed in the medium in the slurry for the porous film. Represents what to do. Therefore, for example, when the degree of swelling of the binder can be changed by drying to produce a porous film, the degree of swelling of the binder after the degree of swelling has been changed is evaluated.
  • the method for measuring the “degree of swelling with respect to the non-aqueous electrolyte after the formation of the porous film” is as follows.
  • An aqueous dispersion or aqueous solution containing a binder as a sample is prepared, and the solid content concentration is adjusted to 10% by weight.
  • the aqueous dispersion or aqueous solution whose concentration is adjusted is poured into a silicon container so as to have a dry thickness of 1 mm and dried to produce a 1 cm ⁇ 1 cm square film. In this case, the drying is performed under the drying conditions for obtaining the same binder as that contained in the porous film. And the weight M0 of this film is measured. Thereafter, the film is immersed in a nonaqueous electrolytic solution at 60 ° C. for 72 hours, and the weight M1 of the film after immersion is measured. From the measured weights M0 and M1, the degree of swelling is calculated from the formula (M1-M0) / M0.
  • the nonaqueous electrolytic solution for evaluating the degree of swelling of the binder a solution obtained by adding 2% by volume of vinylene carbonate (VC) to a LiPF 6 solution having a concentration of 1.0 M is used.
  • VC vinylene carbonate
  • Examples of means for allowing the porous membrane binder A to have the above-described degree of swelling include, for example, the types of polymer monomers that can be used as the material for the porous membrane binder A, and the crosslinking degree and molecular weight of the polymer. And so on.
  • the binder A for porous film is formed of a polymer.
  • the polymer that can be a material for the porous membrane binder A is such that the porous membrane binder A is in the form of particles, and the degree of swelling of the porous membrane binder A with respect to the non-aqueous electrolyte after the formation of the porous membrane is as described above. Any one can be used as long as it falls within the range.
  • the polymer which can become the material of the binder A for porous films may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • Preferred examples of the polymer that can be used as the material for the binder A for porous membrane include styrene / butadiene copolymer (SBR), acrylonitrile / butadiene copolymer (NBR), hydrogenated SBR, hydrogenated NBR, and styrene-isoprene. -Styrene block copolymers (SIS), acrylic polymers and the like. Among these, acrylic polymers are more preferable because they can be used in any porous film on the positive electrode side and the negative electrode side and are excellent in versatility.
  • the acrylic polymer is a polymer containing a (meth) acrylic acid ester monomer unit.
  • the (meth) acrylic acid ester monomer unit represents a structural unit having a structure formed by polymerizing a (meth) acrylic acid ester monomer.
  • Examples of the (meth) acrylic acid ester monomer include a compound represented by CH 2 ⁇ CR a —COOR b .
  • R a represents a hydrogen atom or a methyl group
  • R b represents an alkyl group or a cycloalkyl group.
  • Examples of (meth) acrylate monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, acrylic N-amyl acid, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, hexyl acrylate, nonyl acrylate, lauryl acrylate, acrylic Acrylates such as stearyl acid and benzyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-a
  • acrylate is preferable, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable in that the strength of the porous film can be improved. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
  • the proportion of the (meth) acrylic acid ester monomer unit in the acrylic polymer that can be the material of the binder A for porous membranes is preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. Yes, preferably 99% by weight or less, more preferably 98% by weight or less, particularly preferably 97% by weight or less.
  • the acrylic polymer may include a (meth) acrylonitrile monomer unit.
  • the (meth) acrylonitrile monomer unit represents a structural unit having a structure formed by polymerizing (meth) acrylonitrile. Since an acrylic polymer containing a combination of a (meth) acrylonitrile monomer unit and a (meth) acrylic acid ester monomer unit is stable to oxidation and reduction, it is easy to obtain a long-life battery.
  • the acrylic polymer may contain only a structural unit having a structure formed by polymerizing acrylonitrile as a (meth) acrylonitrile monomer unit, or a structure having a structure formed by polymerizing methacrylonitrile. It may contain only units, and it contains a combination of both a structural unit having a structure formed by polymerizing acrylonitrile and a structural unit having a structure formed by polymerizing methacrylonitrile in any ratio. Also good.
  • the proportion of the (meth) acrylonitrile monomer unit in the acrylic polymer that can be the material for the binder A for the porous membrane is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and particularly preferably 1.0%. % By weight or more, preferably 20.0% by weight or less, more preferably 10.0% by weight or less, and particularly preferably 5.0% by weight or less.
  • the acrylic polymer may include a styrene monomer unit.
  • the styrene monomer unit represents a structural unit having a structure formed by polymerizing styrene. Since an acrylic polymer containing a combination of a styrene monomer unit and a (meth) acrylic acid ester monomer unit is stable to oxidation and reduction, it is easy to obtain a battery having a long life.
  • the proportion of the styrene monomer unit in the acrylic polymer that can be the material for the binder A for the porous membrane is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and particularly preferably 1.0% by weight or more. It is preferably 20.0% by weight or less, more preferably 10.0% by weight or less, and particularly preferably 5.0% by weight or less.
  • the total ratio of the (meth) acrylonitrile monomer unit and the styrene monomer unit in the acrylic polymer is predetermined. It is preferable to be within the range. Specifically, the total ratio is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, particularly preferably 1.0% by weight or more, and preferably 20.0% by weight. Hereinafter, it is more preferably 10.0% by weight or less, particularly preferably 5.0% by weight or less.
  • the life of the secondary battery can be particularly prolonged.
  • the mechanical strength of a porous film can be raised by making it below an upper limit.
  • the acrylic polymer can contain an ethylenically unsaturated carboxylic acid monomer unit.
  • the ethylenically unsaturated carboxylic acid monomer unit represents a structural unit having a structure formed by polymerizing an ethylenically unsaturated carboxylic acid monomer.
  • Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acid and derivatives thereof, ethylenically unsaturated dicarboxylic acid and acid anhydrides thereof, and derivatives thereof.
  • Examples of the ethylenically unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid and the like.
  • Examples of derivatives of ethylenically unsaturated monocarboxylic acids include 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid, Examples thereof include ⁇ -diaminoacrylic acid.
  • Examples of the ethylenically unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid and the like.
  • Examples of the acid anhydride of the ethylenically unsaturated dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, dimethyl maleic anhydride and the like.
  • Examples of derivatives of ethylenically unsaturated dicarboxylic acids include methyl allyl maleate such as methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid; diphenyl maleate, nonyl maleate, Examples thereof include maleic acid esters such as decyl maleate, dodecyl maleate, octadecyl maleate and fluoroalkyl maleate.
  • ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid are preferable from the viewpoint of enhancing the water dispersibility of the binder A for porous membranes.
  • One of these may be used alone, or two or more of these may be used in combination at any ratio.
  • the ratio of the ethylenically unsaturated carboxylic acid monomer unit in the acrylic polymer that can be a material for the binder A for porous membranes is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and particularly preferably 1%. It is 0.0% by weight or more, preferably 10.0% by weight or less, more preferably 6.0% by weight or less, and particularly preferably 4.0% by weight or less.
  • the acrylic polymer can contain a crosslinkable monomer unit.
  • the crosslinkable monomer unit represents a structural unit having a structure formed by polymerizing a crosslinkable monomer.
  • a crosslinkable monomer represents the monomer which can form a crosslinked structure by superposition
  • a monomer having heat crosslinkability is usually mentioned. More specifically, a monofunctional monomer having a thermally crosslinkable crosslinkable group and one olefinic double bond per molecule; a multifunctional having two or more olefinic double bonds per molecule Monomer.
  • crosslinkable group examples include an epoxy group, an N-methylolamide group, an oxetanyl group, an oxazoline group, and an allyl group.
  • One kind of these crosslinkable groups may be used, or two or more kinds may be used in any combination.
  • an epoxy group and an allyl group are preferable because the crosslinking and the crosslinking density can be easily adjusted.
  • crosslinkable monomer having an epoxy group as a thermally crosslinkable group and having an olefinic double bond examples include vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl.
  • Unsaturated glycidyl ethers such as ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene Monoepoxides of dienes or polyenes such as; alkenyl epoxides such as 3,4-epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; and glycidyl acrylate, glycidyl methacrylate, Glycidyl crotonate, Unsaturated carboxylic acids such as glycidyl-4-heptenoate, glycidyl sorbate, glycidyl linoleate, glycidyl-4-methyl-3-pentenoate, glycidyl este
  • crosslinkable monomer having an allyl group as a thermally crosslinkable group and having an olefinic double bond examples include allyl acrylate and allyl methacrylate.
  • crosslinkable monomer having an N-methylolamide group as a thermally crosslinkable group and having an olefinic double bond have a methylol group such as N-methylol (meth) acrylamide (meta ) Acrylamides.
  • crosslinkable monomer having an oxetanyl group as a thermally crosslinkable group and having an olefinic double bond examples include 3-((meth) acryloyloxymethyl) oxetane, 3-((meth) Acryloyloxymethyl) -2-trifluoromethyloxetane, 3-((meth) acryloyloxymethyl) -2-phenyloxetane, 2-((meth) acryloyloxymethyl) oxetane, and 2-((meth) acryloyloxymethyl) ) -4-Trifluoromethyloxetane.
  • crosslinkable monomer having an oxazoline group as a heat crosslinkable group and having an olefinic double bond examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2- Oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline.
  • crosslinkable monomers having two or more olefinic double bonds per molecule examples include allyl (meth) acrylate, ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth).
  • ethylene dimethacrylate, allyl glycidyl ether, and glycidyl methacrylate are particularly preferable as the crosslinkable monomer. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
  • the proportion of the crosslinkable monomer unit in the acrylic polymer that can be the material for the binder A for porous membrane is preferably 0.2% by weight or more, more preferably 0.6% by weight or more, and particularly preferably 1.0% by weight. Above, preferably 5.0% by weight or less, more preferably 4.0% by weight or less, and particularly preferably 3.0% by weight or less.
  • the acrylic polymer may contain an arbitrary structural unit other than the structural units described above.
  • monomers corresponding to these arbitrary structural units include styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, ⁇ -methyl.
  • Styrene monomers such as styrene and divinylbenzene; Olefins such as ethylene and propylene; Diene monomers such as butadiene and isoprene; Monomers containing halogen atoms such as vinyl chloride and vinylidene chloride; Vinyl acetate and propionic acid Vinyl esters such as vinyl and vinyl butyrate; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone and isopropenyl vinyl ketone; N Heterocycle-containing vinyl compounds such as vinylpyrrolidone, vinylpyridine, and vinylimidazole; unsaturated carboxylic acid amide monomers such as acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, and N, N-dimethyl
  • the number average particle size of the binder A for porous membrane is preferably 0.10 ⁇ m or more, more preferably 0.15 ⁇ m or more, particularly preferably 0.20 ⁇ m or more, preferably 1.00 ⁇ m or less, more preferably 0.80 ⁇ m. Hereinafter, it is particularly preferably 0.60 ⁇ m or less.
  • the adhesive point of a nonelectroconductive particle and the binder A for porous films can be increased, and binding property can be made high.
  • the number average particle size of the porous membrane binder A represents the number average particle size in a state where the porous membrane binder A is not swollen in the non-aqueous electrolyte.
  • the amount of the porous membrane binder A is preferably 4.0 parts by volume or more, more preferably 8.0 parts by volume or more, and particularly preferably 12.0 parts by volume or more with respect to 100 parts by volume of the non-conductive particles.
  • the amount is preferably 40.0 parts by volume or less, more preferably 35.0 parts by volume or less, and particularly preferably 30.0 parts by volume or less.
  • the method for producing the porous membrane binder A is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method may be used.
  • the emulsion polymerization method and the suspension polymerization method are preferable because they can be polymerized in water and can be suitably used as the material for the slurry for the porous membrane as it is.
  • dispersant examples include benzene sulfonates such as sodium dodecyl benzene sulfonate and sodium dodecyl phenyl ether sulfonate; alkyl sulfates such as sodium lauryl sulfate and sodium tetradodecyl sulfate; sodium dioctyl sulfosuccinate, sodium dihexyl sulfosuccinate and the like.
  • benzene sulfonates such as sodium dodecyl benzene sulfonate and sodium dodecyl phenyl ether sulfonate
  • alkyl sulfates such as sodium lauryl sulfate and sodium tetradodecyl sulfate
  • sodium dioctyl sulfosuccinate sodium dihexyl sulfosuccinate and the like.
  • Sulfosuccinates Sulfosuccinates; fatty acid salts such as sodium laurate; ethoxy sulfate salts such as polyoxyethylene lauryl ether sulfate sodium salt, polyoxyethylene nonylphenyl ether sulfate sodium salt; alkane sulfonate; alkyl ether phosphate sodium salt; Polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan lauryl ester, polyoxyethylene-polyoxy Nonionic emulsifier such as propylene block copolymer; gelatin, maleic anhydride-styrene copolymer, polyvinyl pyrrolidone, sodium polyacrylate, polyvinyl alcohol having a polymerization degree of 700 or higher and a saponification degree of 75% or higher.
  • Benzenesulfonates such as sodium dodecylbenzenesulfonate and sodium dodecylphenylethersulfonate
  • alkyl sulfates such as sodium lauryl sulfate and sodium tetradodecylsulfate
  • oxidation resistance is more preferable. From this point, it is a benzenesulfonate such as sodium dodecylbenzenesulfonate and sodium dodecylphenylethersulfonate.
  • the amount of the dispersant may be arbitrarily set, and is usually 0.01 to 10 parts by weight with respect to 100 parts by weight of the total amount of monomers.
  • porous membrane binder B is a particulate binder. Therefore, the particles of the binder B for the porous film are dispersed in the medium in the slurry for the porous film.
  • the porous membrane binder B is usually formed of a material insoluble in the medium. Therefore, for example, when water is used as the medium, the porous membrane binder B is preferably formed of a water-insoluble material.
  • the binder B for porous membranes has a degree of swelling with respect to the non-aqueous electrolyte after the formation of the porous membrane is usually 10 times or more, preferably 11 times or more, more preferably 12 times or more, and usually 50 times or less. , Preferably 35 times or less, more preferably 20 times or less.
  • the degree of swelling of the porous membrane binder B can be measured by the same method as the measurement of the degree of swelling of the porous membrane binder A.
  • the porous membrane binder B can sufficiently contact the electrode.
  • the binding property with the electrode can be improved.
  • the binding property of the binder B for porous membranes can be made high by making it below an upper limit, the binding property of a porous membrane and an electrode can be improved.
  • Examples of means for allowing the porous membrane binder B to have the above-described degree of swelling include, for example, the types of polymer monomers that can be used as the material for the porous membrane binder B, and the crosslinking degree and molecular weight of the polymer. And so on.
  • the porous membrane binder B is formed of a polymer.
  • the polymer that can be a material for the porous membrane binder B is such that the porous membrane binder B is in the form of particles, and the degree of swelling of the porous membrane binder B with respect to the non-aqueous electrolyte after the formation of the porous membrane is as described above. As long as it falls within the range, any one can be used.
  • the polymer which can become the material of the binder B for porous films may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • Preferable examples of the polymer that can be used as the material for the binder B for porous membrane include styrene / butadiene copolymer (SBR), acrylonitrile / butadiene copolymer (NBR), hydrogenated SBR, hydrogenated NBR, and styrene-isoprene. -Styrene block copolymers (SIS), acrylic polymers and the like. Among these, acrylic polymers are more preferable because they can be used in any porous film on the positive electrode side and the negative electrode side and are excellent in versatility.
  • SBR styrene / butadiene copolymer
  • NBR acrylonitrile / butadiene copolymer
  • SIS styrene block copolymers
  • acrylic polymers are more preferable because they can be used in any porous film on the positive electrode side and the negative electrode side and are excellent in versatility.
  • examples of the (meth) acrylic acid ester monomer corresponding to the (meth) acrylic acid ester monomer unit can be a material for the porous membrane binder A. Examples similar to those mentioned in the description of the acrylic polymer are given. Moreover, those (meth) acrylic acid ester monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the proportion of (meth) acrylic acid ester monomer units in the acrylic polymer that can be a material for the binder B for porous membranes is preferably 20.0% by weight or more, more preferably 30.0% by weight or more, and particularly preferably 40%. It is 0.0% by weight or more, preferably 80.0% by weight or less, more preferably 70.0% by weight or less, and particularly preferably 60.0% by weight or less.
  • the ratio of the (meth) acrylic acid ester monomer unit equal to or higher than the lower limit of the above range, the affinity between the binder B for porous film and the electrode is improved, and thus the binding force between the electrode and the porous film is increased. be able to.
  • strength of the binder B for porous films in electrolyte solution can be raised by setting it as an upper limit or less, the binding force of an electrode and a porous film can be raised.
  • the acrylic polymer that can be the material of the binder B for the porous membrane can contain a (meth) acrylonitrile monomer unit.
  • the acrylic polymer may contain only a structural unit having a structure formed by polymerizing acrylonitrile as a (meth) acrylonitrile monomer unit, or a structure formed by polymerizing methacrylonitrile.
  • the structural unit having a structure formed by polymerizing acrylonitrile and the structural unit having a structure formed by polymerizing methacrylonitrile may be combined at an arbitrary ratio. May be included.
  • the proportion of the (meth) acrylonitrile monomer unit in the acrylic polymer that can be the material for the binder B for porous membrane is preferably 5.0% by weight or more, more preferably 10.0% by weight or more, and particularly preferably 15.0%. It is at least 5% by weight, preferably at most 55.0% by weight, more preferably at most 50.0% by weight, particularly preferably at most 40.0% by weight.
  • the ratio of the (meth) acrylonitrile monomer unit more than the lower limit of the above range, the affinity between the porous membrane binder B and the electrode is improved, so that the binding force between the electrode and the porous membrane can be increased. it can.
  • strength of the binder B for porous films in electrolyte solution can be raised by setting it as an upper limit or less, the binding force of an electrode and a porous film can be raised.
  • the acrylic polymer that can be a material for the binder B for the porous membrane can contain an ethylenically unsaturated carboxylic acid monomer unit.
  • the ethylenically unsaturated carboxylic acid monomer corresponding to the ethylenically unsaturated carboxylic acid monomer unit are the same as those given in the description of the acrylic polymer that can be used as the material for the binder A for the porous membrane. Is mentioned.
  • these ethylenically unsaturated carboxylic acid monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the ratio of the ethylenically unsaturated carboxylic acid monomer unit in the acrylic polymer that can be the material for the binder B for the porous membrane is preferably 0.2% by weight or more, more preferably 0.4% by weight or more, and particularly preferably 0%. It is 0.6% by weight or more, preferably 10.0% by weight or less, more preferably 6.0% by weight or less, and particularly preferably 4.0% by weight or less.
  • the acrylic polymer that can be the material of the binder B for the porous film can contain a crosslinkable monomer unit.
  • the crosslinkable monomer corresponding to the crosslinkable monomer unit include the same examples as mentioned in the description of the acrylic polymer that can be the material for the porous membrane binder A.
  • those crosslinkable monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the proportion of the crosslinkable monomer unit in the acrylic polymer that can be the material of the binder B for porous membrane is preferably 0.10% by weight or more, more preferably 0.20% by weight or more, and particularly preferably 0.50% by weight.
  • the content is preferably 20.0% by weight or less, more preferably 15.0% by weight or less, and particularly preferably 10.0% by weight or less.
  • the acrylic polymer that can be the material of the binder B for the porous membrane can contain any structural unit other than the structural units described above.
  • Examples of the monomer corresponding to these arbitrary structural units include the same examples as mentioned in the description of the acrylic polymer that can be the material of the binder A for porous membranes.
  • those monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the number average particle diameter (b) of the porous membrane binder B is preferably smaller than the number average particle size (a) of the porous membrane binder A. That is, it is preferable that the number average particle size (a) of the porous membrane binder A and the number average particle size (b) of the porous membrane binder B satisfy the relationship (a)> (b). In general, particles having a small number average particle diameter tend to cause migration. Therefore, when the slurry for porous membranes is applied onto the substrate to form a slurry layer, the binder B for porous membranes having a small number average particle diameter tends to collect on the surface of the slurry layer opposite to the substrate.
  • the porous membrane binder B can be collected on the surface of the porous membrane. For this reason, since the binding action between the porous membrane and the electrode due to the swollen porous membrane binder B can be exerted remarkably, the binding property between the secondary battery separator and the electrode can be enhanced.
  • the specific number average particle diameter of the binder B for porous membrane is preferably 0.02 ⁇ m or more, more preferably 0.05 ⁇ m or more, particularly preferably 0.08 ⁇ m or more, preferably 0.60 ⁇ m or less, more preferably It is 0.40 ⁇ m or less, particularly preferably 0.20 ⁇ m or less.
  • the number average particle diameter not less than the lower limit of the above range, the adhesive force between the porous membrane and the electrode can be increased.
  • the porous membrane binder B by making it below the upper limit value, migration occurs in the porous membrane binder B in the slurry layer, and the porous membrane binder B can be effectively collected on the surface of the porous membrane.
  • the number average particle size of the porous membrane binder B represents the number average particle size in a state where the porous membrane binder B is not swollen in the non-aqueous electrolyte.
  • the amount of the binder B for porous membrane is preferably 4.0 parts by volume or more, more preferably 8.0 parts by volume or more, and particularly preferably 12.0 parts by volume or more with respect to 100 parts by volume of the non-conductive particles.
  • the amount is preferably 40.0 parts by volume or less, more preferably 35.0 parts by volume or less, and particularly preferably 30.0 parts by volume or less.
  • the method for producing the porous membrane binder B is not particularly limited, and for example, it can be produced by the same method as that for the porous membrane binder A.
  • porous membrane binder C is a non-particulate binder. This porous film binder C is dissolved in the medium. At this time, in the porous film slurry, a part of the porous film binder C is released in the medium, but another part is adsorbed on the surface of the nonconductive particles. Can be improved.
  • the porous membrane binder C is usually formed of a material that is soluble in the medium. Therefore, for example, when water is used as the medium, the porous membrane binder C is preferably formed of a water-soluble material.
  • the binder C for porous membranes can have a degree of swelling with respect to the nonaqueous electrolytic solution after the formation of the porous membrane is usually less than 5 times, preferably less than 3.5 times, more preferably less than 2 times.
  • the degree of swelling related to the porous film binder C can be measured by the same method as the measurement of the degree of swelling of the porous film binder A.
  • the heat resistance of the porous membrane can be enhanced by setting the degree of swelling of the binder C for porous membrane to the non-aqueous electrolyte after the formation of the porous membrane to be less than the upper limit of the above range. Therefore, since the shrinkage of the porous film can be prevented during heating, the safety of the secondary battery can be improved.
  • the lower limit of the degree of swelling of the porous membrane binder C with respect to the nonaqueous electrolytic solution after the formation of the porous membrane is not particularly limited, but can usually be 1 or more times.
  • Examples of means for allowing the porous membrane binder C to have the above-described degree of swelling include, for example, the types of polymer monomers that can be used as the material for the porous membrane binder C, and the crosslinking degree and molecular weight of the polymer. And so on.
  • the porous membrane binder C is formed of a polymer.
  • the polymer that can be a material for the porous membrane binder C is such that the porous membrane binder C is non-particulate and the degree of swelling of the porous membrane binder C with respect to the non-aqueous electrolyte after the formation of the porous membrane is as described above. As long as it falls within the range, any one can be used.
  • the polymer which can become the material of the binder C for porous films may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the polymer that can be used as the material for the binder C for porous membrane include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, ammonium salts thereof, and alkali metal salts; (modified) poly (meta) Acrylic acid and ammonium salts thereof and alkali metal salts; (modified) polyvinyl alcohol, acrylic acid or a copolymer of acrylic acid salt and vinyl alcohol, maleic anhydride or a copolymer of maleic acid or fumaric acid and vinyl alcohol, etc.
  • polyvinyl alcohols polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified polyacrylic acid, oxidized starch, phosphate starch, casein, various modified starches and the like.
  • (modified) poly means “unmodified poly” and “modified poly”. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
  • the amount of the binder C for porous membrane is preferably 0.50 part by volume or more, more preferably 1.0 part by volume or more, and particularly preferably 1.5 part by volume or more with respect to 100 parts by volume of the non-conductive particles.
  • the amount is preferably 6.0 parts by volume or less, more preferably 5.0 parts by volume or less, and particularly preferably 4.0 parts by volume or less.
  • the heat resistance of a porous film can be improved by making the quantity of the binder C for porous films more than the lower limit of the said range.
  • the ion permeability of a porous membrane can be made high by setting it as below the upper limit of the said range, the resistance of a secondary battery can be made small.
  • an aqueous medium is preferably used as the medium.
  • the aqueous medium include water; ketones such as diacetone alcohol and ⁇ -butyrolactone; alcohols such as ethyl alcohol, isopropyl alcohol and normal propyl alcohol; propylene glycol monomethyl ether, methyl cellosolve, ethyl cellosolve, and ethylene glycol tertiary.
  • Glycol ethers such as butyl ether, butyl cellosolve, 3-methoxy-3-methyl-1-butanol, ethylene glycol monopropyl ether, diethylene glycol monobutyl pyrether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether; 1,3-dioxolane, 1 , 4-dioxolane, ethers such as tetrahydrofuran; and the like.
  • water is preferable from the viewpoint that there is no flammability and that a dispersion of particles of the binders A and B for the porous membrane can be easily obtained.
  • These media may be used alone or in combination of two or more at any ratio.
  • the amount of the medium can usually be arbitrarily set within a range in which the slurry for the porous membrane has a viscosity that does not impair workability when producing the porous membrane.
  • the solid content concentration of the slurry for the porous membrane is preferably 1% by volume or more, more preferably 5% by volume or more, particularly preferably 10% by volume or more, preferably 50% by volume or less, more preferably
  • the amount of the medium is set so as to be 40% by volume or less, particularly preferably 30% by volume or less.
  • the slurry for porous film may contain arbitrary components other than the non-conductive particles, the binder for porous film, and the medium.
  • optional components those which do not exert an excessively unfavorable influence on the battery reaction can be used.
  • Optional components include, for example, isothiazoline compounds, chelate compounds, pyrithione compounds, dispersants, leveling agents, antioxidants, thickeners, antifoaming agents, wetting agents, and electrolytes having a function of inhibiting electrolyte decomposition.
  • a liquid additive etc. are mentioned.
  • arbitrary components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the slurry for the porous film is produced by mixing, for example, non-conductive particles, the binder A for the porous film, the binder B for the porous film, the binder C for the porous film and the medium, and any components used as necessary. sell.
  • the mixing method There is no restriction
  • the mixing method There is no particular limitation on the mixing method. Usually, in order to disperse non-conductive particles quickly, mixing is performed using a disperser as a mixing device.
  • the disperser is preferably an apparatus capable of uniformly dispersing and mixing the above components.
  • examples include a ball mill, a sand mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, and a planetary mixer.
  • a high dispersion apparatus such as a bead mill, a roll mill, or a fill mix is particularly preferable because a high dispersion share can be added.
  • porous membrane for secondary battery separator contains non-conductive particles and a binder for the porous film. Since the voids between the non-conductive particles form pores in the porous film, the porous film has a porous structure. For this reason, ion can permeate
  • the porous film binder includes a combination of the porous film binder A, the porous film binder B, and the porous film binder C described above. That is, a particulate porous membrane binder A, a particulate porous membrane binder B, and a non-particulate porous membrane binder C are included in combination. Moreover, these binder A for porous films, binder B for porous films, and binder C for porous films have the swelling degree of the range mentioned above. Since the porous membrane contains the porous membrane binder A, the porous membrane binder B, and the porous membrane binder C combined in this way, the battery is excellent in both safety and battery characteristics such as high-temperature cycle characteristics and rate characteristics. A secondary battery can be realized.
  • the flexibility of the porous membrane can be increased by the action of the flexible binder A for porous membranes, so that the mechanical strength of the porous membrane can be improved. Therefore, even if a stress is generated in the porous film due to a temperature change or an external force is applied to the porous film, the porous film can be prevented from being damaged.
  • the binder C for porous films exists uniformly in a porous film, and binds nonelectroconductive particles strongly. Therefore, shrinkage of the porous film due to heat can be suppressed.
  • the porous membrane binder A stably binds the porous membrane to the organic separator layer, so that the organic separator layer can be prevented from shrinking.
  • the separator provided with the porous membrane of the present invention can prevent a short circuit even under a harsh environment such as a high temperature environment, so that the safety of the secondary battery can be improved.
  • FIG. 1 is an enlarged cross-sectional view schematically showing the vicinity of the surface of a porous membrane that is not wetted with a non-aqueous electrolyte.
  • FIG. 2 is an enlarged cross-sectional view schematically showing the vicinity of the surface of the porous membrane wet with the non-aqueous electrolyte. As shown in FIG. 1 and FIG.
  • the binding property between the electrode and the porous film can be improved as described above, peeling between the electrode and the porous film can be prevented even when charging and discharging are repeated in a high temperature environment. If peeling between the electrode and the porous film occurs, the distance between the positive electrode and the negative electrode is increased, and thus the resistance of the secondary battery is increased. However, if the porous film of the present invention is used, peeling between the electrode and the porous film can be prevented, and thus the increase in resistance as described above can be prevented, so that it is presumed that high temperature cycle characteristics can be improved.
  • the porous membrane binder B (10) is in the form of particles. Therefore, since the porous membrane binder B (10) does not easily block the pores of the porous membrane, the ion permeability can be increased. Therefore, it is difficult to increase the resistance of the secondary battery. Therefore, it is presumed that the rate characteristics of the secondary battery can be enhanced because it is difficult to increase the resistance of the secondary battery even though the separator is provided with a porous film for improving safety.
  • the porous membrane binder A (20) hardly swells in the non-aqueous electrolyte. Therefore, it is speculated that the porous membrane binder A (20) can bind the nonconductive particles (30) to each other and the nonconductive particles (30) and the organic separator (not shown) well. Furthermore, since the porous membrane binder A (20) is in the form of particles, it is difficult to block the pores of the porous membrane, so it is assumed that the resistance of the secondary battery is suppressed.
  • the porous membrane binder C (40) hardly swells in the non-aqueous electrolyte. Therefore, it is surmised that the binder C (40) for porous membranes can strongly bind the nonconductive particles (30) to each other even during high temperature nonaqueous electrolysis.
  • the porous membrane binder includes a particulate porous membrane binder A, a particulate porous membrane binder B, and a non-particulate porous membrane binder C.
  • the porous membrane binders A and B in the porous membrane do not necessarily mean that the particle shapes of the porous membrane binders A and B in the porous membrane slurry are maintained as they are.
  • the porous membrane binder A (20) and the porous membrane binder B (10) are usually irregular because they are sandwiched between non-conductive particles (30) in the porous membrane. It becomes a shape and tends to be an irregular shape.
  • the particulate porous membrane binder A (20) and the porous membrane binder B (10) are different from the non-particulate porous membrane binder C (40), and the porous membrane binder A (20)
  • the binder A (20) and the porous membrane binder B (10) are present together for each position.
  • the state of the binder A (20) for the porous film and the binder B (10) for the porous film that are gathered together with the non-particulate porous film binder C (40) is referred to as particulate.
  • the total amount of the binder for the porous membrane in the porous membrane is preferably 1% by volume or more, more preferably 5% by volume or more, particularly preferably 10% by volume or more, preferably 50% by volume or less, more preferably 45% by volume or less. Especially preferably, it is 40 volume% or less.
  • the porous film binder B is located on the opposite side of the base material from the base material side part of the porous film. It is preferable that many gather. Thereby, the opposite side to the base material of a porous film and an electrode can be bonded together with high binding force. This can be realized, for example, by appropriately setting the relationship between the number average particle diameters of the porous membrane binder A and the porous membrane binder B.
  • the thickness of the porous membrane is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, particularly preferably 0.3 ⁇ m or more, preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, and particularly preferably 10 ⁇ m or less.
  • the porous film of the present invention can be produced by a production method including, for example, applying a slurry for a porous film on a substrate to obtain a slurry layer, and drying the slurry layer.
  • the method of applying the slurry for the porous film there is no limitation on the method of applying the slurry for the porous film.
  • the coating method include a doctor blade method, a dipping method, a die coating method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.
  • the coating amount of the slurry for the porous film is usually in a range where a porous film having a desired thickness can be obtained.
  • the slurry layer is dried.
  • the medium is removed from the slurry layer to obtain a porous film.
  • the drying method include drying with air such as warm air, hot air, and low-humidity air; vacuum drying; drying method by irradiation with infrared rays, far infrared rays, electron beams, and the like.
  • the temperature during drying is preferably 40 ° C. or higher, more preferably 45 ° C. or higher, particularly preferably 50 ° C. or higher, preferably 90 ° C. or lower, more preferably 80 ° C. or lower, particularly preferably 70 ° C. or lower. .
  • the drying time is preferably 5 seconds or more, more preferably 10 seconds or more, particularly preferably 15 seconds or more, preferably 3 minutes or less, more preferably 2 minutes or less, and particularly preferably 1 minute or less.
  • the porous film may be subjected to pressure treatment by a pressing method such as a mold press and a roll press.
  • a pressing method such as a mold press and a roll press.
  • the pressure treatment By performing the pressure treatment, the binding property between the substrate such as the organic separator layer and the porous film can be improved.
  • Heat treatment is also preferable, whereby the thermal crosslinking group contained in the porous membrane binder can be crosslinked to increase the binding force.
  • the separator for secondary batteries of this invention is equipped with the organic separator layer and the porous film of this invention formed on this organic separator layer. Since both the organic separator layer and the porous membrane provided in the secondary battery separator have a porous structure, the battery reaction is not inhibited by the secondary battery separator. Moreover, since the separator for secondary batteries is provided with the porous film of the present invention, a secondary battery excellent in all of safety, high temperature cycle characteristics and rate characteristics can be realized by using the separator for secondary batteries.
  • the organic separator layer for example, a porous substrate having fine pores can be used. By using such an organic separator layer, it is possible to prevent short-circuiting of electrodes without hindering charge / discharge of the battery in the secondary battery.
  • the organic separator layer include microporous membranes and nonwoven fabrics containing polyolefin resins such as polyethylene and polypropylene, aromatic polyamide resins, and the like.
  • the porous film may be provided on only one surface of the organic separator layer or on both surfaces.
  • the thickness of the organic separator layer is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 40 ⁇ m or less, more preferably 30 ⁇ m or less, and particularly preferably 10 ⁇ m or less. Within this range, the resistance due to the organic separator layer in the secondary battery is reduced, and the workability during battery production is excellent.
  • the porous film of the present invention and an organic separator layer may be bonded together.
  • the separator for a secondary battery may be manufactured by carrying out the above-described porous film manufacturing method using an organic separator layer as a base material.
  • the secondary battery of this invention is equipped with a positive electrode, a negative electrode, the separator for secondary batteries of this invention, and electrolyte solution.
  • the secondary battery of the present invention includes a positive electrode, a separator for a secondary battery of the present invention, and a negative electrode in this order, and further includes an electrolytic solution.
  • the secondary battery of the present invention is excellent in all of safety, high-temperature cycle characteristics, and rate characteristics.
  • Each of the positive electrode and the negative electrode as an electrode usually includes a current collector and an electrode active material layer provided on the current collector.
  • the current collector a material having electrical conductivity and electrochemical durability can be used.
  • metal materials such as iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, and platinum are preferable from the viewpoint of heat resistance.
  • aluminum is particularly preferable as the positive electrode current collector
  • copper is particularly preferable as the negative electrode current collector.
  • the shape of the current collector is not particularly limited, but a sheet shape having a thickness of 0.001 mm to 0.5 mm is preferable.
  • the current collector is preferably used after roughening in advance.
  • the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method.
  • the mechanical polishing method for example, an abrasive cloth paper to which abrasive particles are fixed, a grindstone, an emery buff, a wire brush provided with a steel wire, or the like can be used.
  • an intermediate layer may be formed on the current collector surface in order to increase the adhesive strength and conductivity with the electrode active material layer.
  • the electrode active material layer includes an electrode active material.
  • an electrode active material for a positive electrode may be referred to as a “positive electrode active material”
  • an electrode active material for a negative electrode may be referred to as a “negative electrode active material”.
  • electrode active materials for lithium ion secondary batteries will be described in particular. However, the electrode active material is not limited to those listed below.
  • the electrode active material a material capable of reversibly inserting and releasing lithium ions by applying a potential in an electrolytic solution can be used.
  • the electrode active material an inorganic compound or an organic compound may be used.
  • the positive electrode active material is roughly classified into those made of inorganic compounds and those made of organic compounds.
  • Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides.
  • Examples of the transition metal include Fe, Co, Ni, and Mn.
  • inorganic compounds used for the positive electrode active material include LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiFePO 4 , LiFeVO 4, and other lithium-containing composite metal oxides; TiS 2 , TiS 3 , non- Transition metal sulfides such as crystalline MoS 2 ; transition metal oxides such as Cu 2 V 2 O 3 , amorphous V 2 O—P 2 O 5 , MoO 3 , V 2 O 5 , V 6 O 13, etc. Can be mentioned.
  • examples of the positive electrode active material made of an organic compound include conductive polymers such as polyacetylene and poly-p-phenylene.
  • the positive electrode active material which consists of a composite material which combined the inorganic compound and the organic compound.
  • a composite material covered with a carbon material may be produced by reducing and firing an iron-based oxide in the presence of a carbon source material, and the composite material may be used as a positive electrode active material.
  • Iron-based oxides tend to have poor electrical conductivity, but can be used as a high-performance positive electrode active material by using a composite material as described above.
  • you may use as a positive electrode active material what carried out the element substitution of the said compound partially.
  • These positive electrode active materials may be used alone or in combination of two or more at any ratio.
  • the particle size of the positive electrode active material is appropriately selected in consideration of other constituent requirements of the secondary battery.
  • the number average particle diameter of the positive electrode active material is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 50 ⁇ m or less, more preferably 20 ⁇ m or less. It is. When the number average particle diameter of the positive electrode active material is within this range, a battery having a large charge / discharge capacity can be obtained, and handling in producing the slurry for active material layer and the electrode is easy.
  • the negative electrode active material examples include carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads, and pitch-based carbon fibers; and conductive polymers such as polyacene.
  • metals such as silicon, tin, zinc, manganese, iron and nickel, and alloys thereof; oxides of the metals or alloys; sulfates of the metals or alloys; Further, metallic lithium; lithium alloys such as Li—Al, Li—Bi—Cd, and Li—Sn—Cd; lithium transition metal nitride; silicon and the like may be used.
  • an electrode active material having a conductive material attached to the surface by a mechanical modification method may be used. These negative electrode active materials may be used alone or in combination of two or more at any ratio.
  • the particle size of the negative electrode active material is appropriately selected in consideration of other constituent requirements of the secondary battery.
  • the number average particle diameter of the negative electrode active material is preferably 1 ⁇ m or more, more preferably 15 ⁇ m or more, preferably 50 ⁇ m or less, more preferably 30 ⁇ m. It is as follows.
  • the electrode active material layer preferably contains an electrode binder in addition to the electrode active material.
  • an electrode binder By including the electrode binder, the binding property of the electrode active material layer in the electrode is improved, and the strength against the mechanical force is increased in the process of winding the electrode.
  • the electrode active material layer in the electrode is difficult to be detached, the risk of a short circuit due to the desorbed material is reduced.
  • a polymer can be used as the binder for the electrode.
  • a polymer can be used.
  • polyethylene polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, polyacrylonitrile derivatives, and the like may be used.
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • FEP tetrafluoroethylene-hexafluoropropylene copolymer
  • polyacrylic acid derivatives polyacrylonitrile derivatives, and the like
  • the binder for the porous film may be used.
  • the binder for electrodes one type may be used alone, or two or more types may be used in combination at any ratio.
  • the amount of the binder for the electrode in the electrode active material layer is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, particularly preferably 0.5 parts by weight or more with respect to 100 parts by weight of the electrode active material. It is preferably 5 parts by weight or less, more preferably 4 parts by weight or less, and particularly preferably 3 parts by weight or less. When the amount of the electrode binder is within the above range, it is possible to prevent the electrode active material from dropping from the electrode without inhibiting the battery reaction.
  • the electrode active material layer may contain any component other than the electrode active material and the electrode binder as long as the effects of the present invention are not significantly impaired. Examples thereof include a conductive material and a reinforcing material.
  • arbitrary components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
  • the conductive material examples include conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube; carbon powder such as graphite; fiber and foil of various metals; .
  • conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube
  • carbon powder such as graphite
  • fiber and foil of various metals .
  • the reinforcing material for example, various inorganic and organic spherical, plate, rod or fiber fillers can be used.
  • the amount of the conductive material and the reinforcing agent used is usually 0 part by weight or more, preferably 1 part by weight or more, preferably 20 parts by weight or less, more preferably 10 parts by weight, with respect to 100 parts by weight of the electrode active material. It is as follows.
  • the thickness of the electrode active material layer is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, preferably 300 ⁇ m or less, more preferably 250 ⁇ m or less for both the positive electrode and the negative electrode.
  • the method for producing the electrode active material layer is not particularly limited.
  • the electrode active material layer can be produced by, for example, applying an electrode active material and a medium, and, if necessary, a slurry for an active material layer containing an electrode binder and optional components onto a current collector and drying it.
  • As the medium either water or an organic solvent can be used.
  • Electrolyte As the electrolytic solution, for example, a solution obtained by dissolving a lithium salt as a supporting electrolyte in a non-aqueous solvent can be used.
  • the lithium salt include LiPF 6 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAlCl 4 , LiClO 4 , CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi , (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and the like.
  • LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferably used.
  • One of these may be used alone, or two or more of these may be used in combination at any ratio.
  • the amount of the supporting electrolyte is preferably 1% by weight or more, more preferably 5% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less with respect to the electrolytic solution. By keeping the amount of the supporting electrolyte within this range, the ionic conductivity can be increased and the charging characteristics and discharging characteristics of the secondary battery can be improved.
  • a solvent capable of dissolving the supporting electrolyte can be used.
  • the solvent include alkyl carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl ethyl carbonate (MEC); Esters such as butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide;
  • DMC dimethyl carbonate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • BC butylene carbonate
  • MEC methyl ethyl carbonate
  • Esters such as butyrolactone and methyl formate
  • ethers such as 1,2-dimethoxyethane and tetrahydrofuran
  • sulfur-containing compounds such as sulfolane
  • an additive may be included in the electrolytic solution as necessary.
  • carbonate compounds such as vinylene carbonate (VC) are preferable.
  • An additive may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
  • an electrode and a separator for a secondary battery are appropriately combined and stacked, and rolled, folded, etc. according to the shape of the battery, put into a battery container, and an electrolyte solution is injected into the battery container. And sealing.
  • an overcurrent prevention element such as a fuse or a PTC element, a lead plate, an expanded metal, or the like may be inserted to prevent overcharging / discharging or an increase in pressure inside the battery.
  • the shape of the battery may be any of a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, and the like.
  • the film was immersed in a nonaqueous electrolytic solution at 60 ° C. for 72 hours, and the weight M1 of the film after immersion was measured. From the measured weights M0 and M1, the degree of swelling was calculated from the formula (M1-M0) / M0.
  • the non-aqueous electrolyte was obtained by adding 2% by volume of vinylene carbonate (VC) to a LiPF 6 solution having a concentration of 1.0 M.
  • VC vinylene carbonate
  • the number average particle size of the binder for a porous membrane contained in the aqueous dispersion was measured using a laser diffraction / scattering particle size distribution analyzer (“LS230” manufactured by Beckman Coulter, Inc.).
  • the number average particle diameter is a particle diameter at which the value of the cumulative distribution is 50% in the particle diameter-number cumulative distribution.
  • a separator and an electrode with a porous film were cut into a width of 10 mm and a length of 50 mm.
  • a separator was disposed on the surface of the cut electrode on the active material layer side to obtain a laminate including the electrode and the separator.
  • the laminate was placed in an aluminum wrapping material.
  • the electrolytic solution was poured into the aluminum packaging material so that no air remained. Furthermore, the opening of the aluminum packaging material was sealed by performing heat sealing at 150 ° C., and a laminate type test cell was produced.
  • the electrolytic solution used was a 2% by volume addition of vinylene carbonate (VC) to a LiPF 6 solution having a concentration of 1.0 M.
  • VC vinylene carbonate
  • a LiPF 6 solution having a concentration of 1.0 M.
  • test cell was allowed to stand at 60 ° C. for 24 hours. Thereafter, the test cell was subjected to heat press using a desktop test press under conditions of a temperature of 90 ° C., a time of 60 seconds, and a pressure of 1 MPa. Thereafter, the test cell was disassembled, and a laminate including an electrode and a separator was taken out and used as a test piece.
  • a cellophane tape was fixed to a horizontal test stand in advance.
  • As the cellophane tape one specified in “JIS Z1522” was used.
  • the test piece was attached to a cellophane tape with the electrode side face down.
  • the test piece was attached to the cellophane tape with the electrode side down.
  • the stress was measured when one end of the separator was pulled in the vertical direction and pulled at a pulling speed of 10 mm / min. Measurement was performed three times for each of the positive electrode and the negative electrode, and the average value was obtained as the adhesive strength. It shows that the greater the adhesive strength, the better the adhesion between the separator and the electrode.
  • Adhesive strength is 2.0 N / m or more
  • B Adhesive strength is 1.0 N / m or more and less than 2.0 N / m
  • C Adhesive strength is 0.5 N / m or more and less than 1.0 N / m
  • D Adhesive strength Less than 0.5 N / m
  • the pouch-type lithium ion secondary battery was allowed to stand for 24 hours, and then charged to 4.2 V at a charge / discharge rate of 0.1 C and discharged to 3.0 V. Thereafter, the battery is charged to 4.2 V at a charge rate of 0.1 C at 25 ° C., discharged to 3.0 V at a discharge rate of 1.0 C, and discharged to 3.0 V at a discharge rate of 3.0 C. Each charge and discharge cycle was performed.
  • the ratio of the battery capacity at 3.0C to the battery capacity at 1.0C was calculated as a percentage to obtain the charge / discharge rate characteristics, and was judged according to the following criteria. It shows that internal resistance is so small that charge / discharge rate characteristic value is high, and high-speed charge / discharge is possible.
  • the pouch-type lithium ion secondary battery was allowed to stand for 24 hours, and then charged to 4.2 V at a charge / discharge rate of 0.1 C and discharged to 3.0 V. Then, it charged to 4.2V at the charge rate of 0.1C at 25 degreeC.
  • a voltage measurement terminal was connected to the cylindrical lithium ion secondary battery and placed inside the heating test apparatus. Thereafter, the temperature was raised to 150 ° C. at a rate of 5 ° C./min and held at 150 ° C. The elapsed time from reaching 150 ° C. until the occurrence of a short circuit was measured. The longer the elapsed time, the higher the safety of the battery.
  • Example 1 (1-1. Production of particulate porous membrane binder A) In a reactor equipped with a stirrer, 0.06 part of sodium dodecyl sulfate, 0.23 part of ammonium persulfate and 100 parts of ion-exchanged water were added and mixed to obtain a mixture A, which was heated to 80 ° C. Meanwhile, in another container, 93.8 parts of butyl acrylate, 2.0 parts of methacrylic acid, 2.0 parts of acrylonitrile, 1.0 part of allyl glycidyl ether, 1.2 parts of N-methylol acrylamide, sodium dodecyl sulfate 0. 1 part and 100 parts of ion-exchanged water were mixed to prepare a dispersion of monomer mixture 1.
  • the dispersion of the monomer mixture 1 was continuously added and polymerized in the mixture A obtained above over 4 hours.
  • the temperature of the reaction system during the continuous addition of the dispersion of the monomer mixture 1 was maintained at 80 ° C. to carry out the reaction. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours. This obtained the aqueous dispersion of the binder A for particulate porous membranes.
  • aqueous dispersion of the binder A for particulate porous membranes After cooling the obtained aqueous dispersion of the binder A for particulate porous membranes to 25 ° C., ammonia water is added thereto to adjust the pH to 7, and then steam is introduced to remove unreacted monomers. Removed. Thereafter, filtration was performed with a 200 mesh (pore diameter: about 77 ⁇ m) stainless steel wire mesh while further adjusting the solid content concentration with ion-exchanged water. As a result, an aqueous dispersion of particulate porous binder A having a number average particle size of 370 nm and a solid content concentration of 40% was obtained.
  • the dispersion of the monomer mixture 2 was continuously added and polymerized in the mixture B obtained above over 4 hours.
  • the temperature of the reaction system during the continuous addition of the dispersion of the monomer mixture 2 was maintained at 70 ° C. to carry out the reaction. After completion of the continuous addition, the reaction was further continued at 80 ° C. for 3 hours. This obtained the aqueous dispersion of the binder B for particulate porous membranes.
  • aqueous dispersion of the particulate porous membrane binder B After cooling the obtained aqueous dispersion of the particulate porous membrane binder B to 25 ° C., ammonia water is added thereto to adjust the pH to 7, and then steam is introduced to remove unreacted monomers. Removed. Thereafter, filtration was performed with a 200 mesh (pore diameter: about 77 ⁇ m) stainless steel wire mesh while further adjusting the solid content concentration with ion-exchanged water. As a result, an aqueous dispersion of a particulate porous membrane binder B having a number average particle diameter of 100 nm and a solid content concentration of 40% was obtained.
  • the slurry for porous membrane was obtained by adjusting and stirring so that it might become 40 weight%.
  • the porous film binder A is 23.1 parts by volume
  • the porous film binder B is 23.1 parts by volume
  • the porous film binder C is 3.7 parts by volume with respect to 100 parts by volume of alumina particles.
  • the total amount of the binder for the porous membrane in the membrane is 33% by volume.
  • a single-layer polyethylene separator (thickness 9 ⁇ m) produced by a wet method was prepared as an organic separator layer.
  • the slurry for porous film obtained in the step (1-3) was applied to both surfaces of the organic separator layer so that the thickness after drying was 2 ⁇ m, respectively, to obtain a slurry layer. Thereafter, the slurry layer was dried at 50 ° C. for 10 minutes to form a porous film, and a separator having a porous film on both sides of the organic separator layer was obtained.
  • step (1-1) the amount of monomer was changed as shown in Table 1 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-2) the amount of monomer was changed as shown in Table 1 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-3) sodium salt of carboxymethyl cellulose (“Selogen BSH-6” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used instead of the sodium salt of carboxymethyl cellulose (“Daicel CMC1220” manufactured by Daicel Finechem) as the binder C for the porous membrane. )). Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-1) the amount of monomer was changed as shown in Table 1 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-2) the amount of monomer was changed as shown in Table 1 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-2) the amount of monomer was changed as shown in Table 2 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • Example 8 In the step (1-3), polyvinylpyrrolidone (“K-15” manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the porous membrane binder C instead of sodium salt of carboxymethyl cellulose (“Daicel CMC1220” manufactured by Daicel Finechem). . Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • Example 9 In the step (1-3), boehmite particles (“BMM” manufactured by Kawai Lime Industry Co., Ltd .; number average particle size 0.9 ⁇ m) were used as non-conductive particles instead of alumina particles. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • Example 10 In a reactor equipped with a stirrer, 0.06 part of sodium dodecyl sulfate, 0.23 part of ammonium persulfate and 100 parts of ion-exchanged water were added and mixed to obtain a mixture X, which was heated to 80 ° C. Meanwhile, in another container, 93.8 parts of butyl acrylate, 2.0 parts of methacrylic acid, 2.0 parts of acrylonitrile, 1.0 part of allyl glycidyl ether, 1.2 parts of N-methylol acrylamide, sodium dodecyl sulfate 0. 1 part and 100 parts of ion-exchanged water were mixed to prepare a dispersion of the monomer mixture X1.
  • the dispersion of the monomer mixture X1 was continuously added and polymerized in the mixture X obtained above over 4 hours.
  • the reaction was carried out while maintaining the temperature of the reaction system at 80 ° C. during continuous addition of the dispersion of the monomer mixture X1. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours. Thereby, an aqueous dispersion of seed polymer particles having a number average particle diameter of 370 nm was obtained.
  • the organic particles were used as non-conductive particles instead of alumina particles. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-1) 93.8 parts of butyl acrylate, 2.0 parts of methacrylic acid, 2.0 parts of acrylonitrile, 1.0 part of allyl glycidyl ether and 1.2 parts of N-methylol acrylamide were used instead of acrylic. 93.8 parts of ethyl acid, 2.0 parts of methacrylic acid, 2.0 parts of styrene and 2.2 parts of ethylene glycol dimethacrylate were used.
  • step (1-2) instead of 50.0 parts of butyl acrylate, 32.0 parts of acrylonitrile, 12.0 parts of styrene, 5.0 parts of ethylene glycol dimethacrylate, and 1.0 part of methacrylic acid, 10.0 parts of ethyl acrylate, 50.0 parts of methyl methacrylate, 4.0 parts of methacrylic acid, 15.0 parts of acrylonitrile, 19.0 parts of styrene and 2.0 parts of ethylene glycol dimethacrylate were used.
  • step (1-3) sodium salt of polyacrylic acid (“Rheojic 260H” manufactured by Toagosei Co., Ltd.) was used in place of the sodium salt of carboxymethyl cellulose (“Daicel CMC1220” manufactured by Daicel Finechem). Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-1) the amount of monomer was changed as shown in Table 2 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-2) the amount of monomer was changed as shown in Table 3 below. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • the dispersion of the monomer mixture 3 was continuously added and polymerized in the mixture C obtained above over 4 hours.
  • the temperature of the reaction system during the continuous addition of the dispersion of the monomer mixture 3 was maintained at 70 ° C. to carry out the reaction.
  • the reaction was further continued at 80 ° C. for 3 hours. Thereafter, steam was introduced to remove unreacted monomers and the mixture was cooled to 25 ° C.
  • Ammonia water was added thereto to adjust the pH to 8, and the solid content concentration was further adjusted with ion-exchanged water. As a result, an aqueous solution of non-particulate porous membrane binder C having a solid content concentration of 10% was obtained.
  • step (1-2) the amount of monomer was changed as shown in Table 3 below. Further, in the step (1-3), in place of the sodium salt of carboxymethyl cellulose (“Daicel CMC1220” manufactured by Daicel Finechem) as the binder C for the porous membrane, the non-particulate porous membrane produced in Comparative Example 3 was used. An aqueous solution of binder C was used in an amount of 1.5 parts in terms of solid content. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-3) an aqueous dispersion of binder A for porous membrane was not used. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-3) the aqueous dispersion of binder B for porous membrane was not used. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • step (1-3) sodium salt of carboxymethyl cellulose was not used. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • the dispersion of the monomer mixture 4 was continuously added and polymerized in the mixture D obtained above over 4 hours.
  • the temperature of the reaction system during the continuous addition of the dispersion of the monomer mixture 4 was maintained at 70 ° C. to carry out the reaction.
  • the reaction was further continued at 80 ° C. for 3 hours. Thereafter, steam was introduced to remove unreacted monomers, and the mixture was cooled to 25 ° C.
  • Ammonia water was added thereto to adjust the pH to 8, and the solid content concentration was adjusted to 10% with ion-exchanged water. Thereby, the aqueous solution containing the binder D for porous films melt
  • step (1-3) instead of the aqueous dispersion of the binder B for porous membrane, 6 parts of the aqueous solution containing the binder D for porous membrane produced in Comparative Example 7 was used in terms of solid content. Except for the above, a separator with a porous membrane and a secondary battery were produced and evaluated in the same manner as in Example 1.
  • Tables 1 to 3 below show the configurations of the porous membrane binders used in the above-described Examples and Comparative Examples.
  • Tables 4 to 7 show the results of the above-described examples and comparative examples. In the following table, the meanings of the abbreviations are as follows.
  • BA butyl acrylate EA: ethyl acrylate MAA: methacrylic acid AN: acrylonitrile AGE: allyl glycidyl ether NMA: N-methylol acrylamide SDS Na: sodium dodecyl sulfate APS: ammonium persulfate ST: styrene EDMA: ethylene glycol dimethacrylate MMA: methyl Methacrylate Solid content: Solid content concentration of aqueous dispersion of binder or aqueous solution containing binder Relationship of binder particle diameter: Number average particle diameter (a) of binder A for porous film and number average particle diameter of binder B for porous film (b The total amount of binder in the porous membrane: CMC Na: sodium salt of carboxymethyl cellulose PVP: polyvinylpyrrolidone PAA Na: polyacrylic acid sodium Lium salt
  • Binder B for porous membrane 10 Binder B for porous membrane 20 Binder A for porous membrane 30 Non-conductive particles 40 Porous membrane binder C

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Abstract

La présente invention concerne une suspension épaisse de film poreux de séparateur de batterie rechargeable contenant des particules non conductrices, un liant de film poreux et un support, et le liant de film poreux contenant : un liant de film poreux (A) qui est sous forme de particules et qui a un degré de gonflement potentiel, par rapport à un électrolyte non aqueux après formation du film poreux, inférieur à un facteur de 10 ; un liant de film poreux (B) qui est sous forme de particules et qui a un degré de gonflement potentiel, par rapport à l'électrolyte non aqueux après formation du film poreux, d'un facteur de 10 à 50 ; et un liant de film poreux (C) qui n'est pas sous forme de particules et qui a un degré de gonflement potentiel, par rapport à l'électrolyte non aqueux après formation du film poreux, inférieur à un facteur de 5.
PCT/JP2013/083716 2012-12-27 2013-12-17 Suspension épaisse de film poreux de séparateur de batterie rechargeable, film poreux de séparateur de batterie rechargeable, procédé de production associé, séparateur de batterie rechargeable et batterie rechargeable WO2014103792A1 (fr)

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JP2016100149A (ja) * 2014-11-20 2016-05-30 日本ゼオン株式会社 非水系二次電池接着層用組成物、非水系二次電池用接着層、非水系二次電池部材、非水系二次電池、および非水系二次電池用接着層の製造方法
JP2017107851A (ja) * 2015-11-30 2017-06-15 旭化成株式会社 蓄電デバイス用セパレータ
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