Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/42—Acrylic resins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
  • H01M50/491—Porosity
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/417—Polyolefins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

• the present invention relates to a porous film for a secondary battery, a porous film slurry for a secondary battery, non-conductive particles, an electrode for a secondary battery, a separator for a secondary battery, and a secondary battery.
• Electrochemical elements such as lithium ion secondary batteries that are small and lightweight, have high energy density, and can be repeatedly charged and discharged are rapidly expanding their demands by taking advantage of their characteristics.
• Lithium ion secondary batteries are used in fields such as mobile phones, notebook personal computers, and electric vehicles because of their relatively high energy density.
• Such a lithium ion secondary battery usually uses a separator in order to prevent a short circuit between the positive electrode and the negative electrode.
• a separator made of a polyolefin-based material such as polyethylene or polypropylene and having physical properties that melts at 200 ° C. or lower is generally used. For this reason, when the lithium ion secondary battery becomes hot, the separator may cause a volume change such as shrinkage or melting. When such a volume change occurs, a short circuit between the positive electrode and the negative electrode, It will cause the release of energy.
• Patent Documents 1 and 2 propose a technique of providing a porous film containing non-conductive particles such as inorganic fine particles on the separator surface or the electrode surface.
• these Patent Documents 1 and 2 by using inorganic fine particles, it is possible to form a porous film having excellent heat resistance and high strength.
• the preparation of inorganic fine particles inevitably contains moisture and metal ions, and therefore it is difficult to reduce the contents of moisture and metal ions.
• moisture and metal ions are mixed in the porous film, the battery performance is adversely affected, so that further improvement of the battery performance by the inorganic fine particles is limited.
• Patent Documents 3 and 4 propose using organic fine particles instead of inorganic fine particles. Since the surface of the organic fine particles can be hydrophobized by selecting the monomer species to be used, it is possible to reduce the moisture mixed into the porous film as compared with the inorganic fine particles. In addition, since it is possible to produce metal ions free, the amount of metal ions mixed can be reduced. Therefore, further improvement in battery performance can be expected by using organic fine particles.
• a porous film containing organic fine particles has a low strength and a low performance to prevent a short circuit of a battery in a high temperature use environment, and a uniform thickness distribution and strength distribution. There is a problem that it is difficult. In particular, if the distribution of film thickness and strength is not uniform, partial cracks are likely to occur, thereby reducing the performance of the battery.
• the porous film containing organic fine particles has a problem that the ion permeability is lowered due to the influence of the organic fine particles.
• JP 2007-294437 A JP 2005-327680 A JP 2006-139978 A JP 2009-64566 A
• An object of the present invention is to provide a porous membrane for a secondary battery having high uniformity of film thickness, excellent reliability in a high temperature environment, and excellent ion permeability.
• the present invention also provides a secondary battery porous membrane slurry and non-conductive particles for producing such a secondary battery porous membrane, and a secondary battery comprising such a secondary battery porous membrane. It is another object of the present invention to provide a battery electrode, a secondary battery separator, and a secondary battery.
• the present inventors have found that the number average particle diameter is 100 to 1000 nm and the BET specific surface area is 14.4 as non-conductive particles for forming a porous membrane for a secondary battery.
• the inventors have found that the above object can be achieved by using polymer particles of 56 to 72.8 m 2 / g, and have completed the present invention.
• a porous membrane for a secondary battery containing non-conductive particles and a binder, wherein the non-conductive fine particles have a number average particle size of 100 to 1000 nm and a BET specific surface area of 14.56 to
• a porous membrane for a secondary battery characterized in that the polymer particle is 72.8 m 2 / g.
• the binder is a (meth) acrylic polymer or a polymer containing a nitrile group, and the (meth) acrylic polymer in the porous membrane for a secondary battery.
• the content of the polymer containing a nitrile group is preferably 3 to 20% by weight.
• a porous membrane slurry for a secondary battery containing non-conductive particles, a binder and a dispersion medium, wherein the non-conductive fine particles have a number average particle size of 100 to 1000 nm and a BET specific surface area.
• a porous membrane slurry for a secondary battery characterized in that the polymer particles are 14.56 to 72.8 m 2 / g.
• the binder is a (meth) acrylic polymer or a polymer containing a nitrile group, and in the solid content contained in the porous membrane slurry for a secondary battery.
• the content ratio of the (meth) acrylic polymer or the polymer containing a nitrile group is preferably 3 to 20% by weight.
• porous membrane for a secondary battery comprising polymer particles having a number average particle diameter of 100 to 1000 nm and a BET specific surface area of 14.56 to 72.8 m 2 / g. Of non-conductive particles.
• an electrode for a secondary battery comprising a current collector, an electrode active material layer, and the porous film for a secondary battery according to any one of the above laminated in this order.
• a separator for a secondary battery wherein the separator is formed by laminating an organic separator and the porous film for a secondary battery according to any one of the above, and
• Secondary battery Is provided.
• a porous membrane for a secondary battery that has high film thickness uniformity, high temperature short circuit resistance (reliability in a high temperature environment), and excellent ion permeability.
• a secondary battery porous membrane slurry and non-conductive particles for producing such a secondary battery porous membrane, and a secondary battery equipped with such a secondary battery porous membrane are provided.
• a battery electrode, a secondary battery separator, and a secondary battery can be provided.
• the porous membrane for a secondary battery of the present invention contains non-conductive particles and a binder, and the non-conductive fine particles have a number average particle diameter of 100 to 1000 nm and a BET specific surface area of 14.56 to 72.8 m 2 / g. It is characterized by comprising polymer particles that are
• Non-conductive particles are composed of polymer particles having a number average particle size of 100 to 1000 nm and a BET specific surface area of 14.56 to 72.8 m 2 / g.
• the non-conductive particles constituting the porous film are those having a number average particle diameter and a BET specific surface area in the above ranges, whereby the secondary battery porous film has a uniform film thickness. It is high and can be excellent in high temperature short circuit resistance (reliability in a high temperature environment) and ion permeability.
• the non-conductive particles by setting the number average particle diameter of the non-conductive particles in the above range, the non-conductive particles have such a degree that the conductive particles have contact portions and the movement of ions is not inhibited. A gap between each other can be formed, thereby improving the high temperature short circuit resistance (reliability in a high temperature environment) while keeping the strength of the porous film high.
• the water permeability of the non-conductive particles is reduced and the ion permeability in the case of the porous film is improved. Can be made.
• the reason why the ion permeability can be improved by setting the BET specific surface area of the non-conductive particles in the above range is not necessarily clear, but by setting the BET specific surface area in the above range, the non-conductive particle is non-conductive.
• the particles have a hollow structure and a structure having a large number of pores connecting the surface of the particles to the hollow portions formed in the particles. It is considered that it is possible to enter through the hollow portion and further through the pore.
• the BET specific surface area of the non-conductive particles includes not only the surface area of the non-conductive particles but also the surface area caused by the pores and hollow portions formed in the non-conductive particles. Will be included.
• the number average particle diameter of the non-conductive particles is 100 to 1000 nm, preferably 300 to 900 nm, more preferably 500 to 900 nm. If the number average particle diameter of the nonconductive particles is too small, the contact portions between the nonconductive particles may be reduced, and the thickness of the porous film may be nonuniform. For this reason, the strength of the porous film is insufficient, and a short circuit of the battery is likely to occur. As a result, the high temperature short circuit resistance (reliability in a high temperature environment) is lowered. On the other hand, if the number average particle size is too large, the gaps between the non-conductive particles are reduced, the ion permeability is lowered, and the rate characteristics are lowered when used in a secondary battery.
• the number average particle diameter of the non-conductive particles is determined by, for example, observing 100 non-conductive particles with a scanning electron microscope, the longest side of the particle image is a, the shortest side is b, and (a + b ) / 2 is calculated for each particle to determine the particle diameter of each particle, and is calculated as an arithmetic average value of the determined particle diameters.
• the nonconductive particles used in the present invention have a BET specific surface area of 14.56 to 72.8 m 2 / g, preferably 14.56 to 36.4 m 2 / g, more preferably 14.56 to 29.12 m 2 / g. If the BET specific surface area is too large, the non-conductive particles become highly hygroscopic, the water content of the non-conductive particles increases, and the cycle characteristics deteriorate when used in a secondary battery. End up. On the other hand, if the BET specific surface area is too small, formation of hollow portions and pores for ions to pass through becomes insufficient, ion permeability decreases, and rate characteristics decrease when used for secondary batteries. .
• the non-conductive particles used in the present invention may have a number average particle diameter and a BET specific surface area within the above ranges, but the average circularity and the coefficient of variation of the particle diameter are preferably within the following ranges.
• the average circularity is preferably 1.05 to 1.60, more preferably 1.07 to 1.45, and still more preferably 1.09 to 1.35.
• the variation coefficient of the particle size is preferably 26% or less, more preferably 23% or less, and still more preferably 20% or less.
• the average circularity is an index indicating how close the observed particle shape is to a circular shape.
• an image obtained by enlarging the non-conductive particles with an electron microscope is taken for the non-conductive particles, 100 particles are arbitrarily selected from the taken images, and the same projected area as the particle image is obtained.
• L 0 / L is circularity
• the average circularity can be calculated from the average of the circularity of 100 particles.
• the coefficient of variation of the particle diameter can be obtained from, for example, the number average particle diameter of the nonconductive particles and the standard deviation thereof.
• the non-conductive particles have a relatively uniform particle size and are more spherical. It is possible to maintain a non-spherical shape, thereby ensuring a contact area between the particles while making the shape of the non-conductive particles relatively uniform. In this case, the film thickness uniformity, strength, and ion permeability can be further improved.
• a method for preparing the non-conductive particles used in the present invention a method in which polymer particles having a number average particle diameter and a BET specific surface area within the above ranges may be employed.
• the monomer mixture containing the above polymerizable monomer is polymerized to obtain seed particles, and the obtained seed particles are used to form hollow portions and pores (between the particle surface and the hollow portion).
• the polymerizable monomer used for producing the seed particles is not particularly limited, but contains at least a polar group from the viewpoint that the adhesion with the binder and the strength of the obtained porous film can be improved. It is preferable to use a monomer.
• the polar group-containing monomer is not particularly limited as long as it contains a polar group in the molecular structure and can be polymerized alone or can be copolymerized with other monomers. Examples of the polar group-containing monomer include a monomer containing a carboxyl group, a monomer containing a sulfonic acid group, a monomer containing a hydroxyl group, a monomer containing an amide group, and a cationic monomer.
• Monomer monomer containing cyano group, monomer containing epoxy group and salts thereof (for example, alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt) And organic amine salts such as ammonium salt, monoethanolamine salt, and triethanolamine salt).
• alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt
• organic amine salts such as ammonium salt, monoethanolamine salt, and triethanolamine salt.
• Examples of the monomer containing a carboxyl group include monocarboxylic acid, dicarboxylic acid, dicarboxylic acid anhydride, and dicarboxylic acid monoester.
• Monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid , ⁇ -diaminoacrylic acid and the like.
• dicarboxylic acid examples include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, and fluoromaleic acid.
• acid anhydride of dicarboxylic acid examples include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
• Dicarboxylic acid monoesters include fumaric acid such as monomethyl maleate, monoethyl maleate, monopropyl maleate, mono n-butyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, mono n-butyl fumarate
• fumaric acid such as monomethyl maleate, monoethyl maleate, monopropyl maleate, mono n-butyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, mono n-butyl fumarate
• monoalkyl esters monomethyl citraconic acid, monoethyl citraconic acid, monopropyl citraconic acid, mono n-butyl citraconic acid, monomethyl itaconate, monoethyl itaconate, monopropyl itaconate, mono n-butyl itaconate and the like.
• Examples of the monomer containing a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamide-2- Examples thereof include methylpropane sulfonic acid and 3-allyloxy-2-hydroxypropane sulfonic acid.
• Monomers containing a hydroxyl group include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol, 5-hexen-1-ol; 2-hydroxyethyl acrylate, acrylic acid- Ethylene such as 2-hydroxypropyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate, di-2-hydroxypropyl itaconate Alkanol esters of unsaturated carboxylic acid; general formula CH 2 ⁇ CR 1 —COO— (C n H 2n O) m —H (m is an integer from 2 to 9, n is an integer from 2 to 4, R 1 is An ester of a polyalkylene glycol represented by (representing hydrogen or a methyl group) and (meth) acrylic acid; 2-hydroxyethyl Mono (meth) acrylic acid esters of dihydroxy esters of dicarboxylic acids such as
• Examples of the monomer containing an amide group include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and the like.
• Examples of the cationic monomer include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate.
• Examples of the monomer containing a cyano group include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile.
• Examples of the monomer containing an epoxy group include glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether.
• polar group-containing monomers a monomer containing a carboxyl group, a monomer containing an amide group, a monomer containing a cyano group, and a monomer containing an epoxy group are preferable.
• the blending ratio of the polar group-containing monomer in the monomer mixture used for producing seed particles is preferably 0.05 to 20% by weight, more preferably 0.05 to 15% by weight, Preferably, it is 0.05 to 10% by weight.
• the blending ratio of the monomer containing a carboxyl group as the polar group-containing monomer is preferably 0 to 10% by weight, more preferably 0.1 to 5% by weight, and a monomer containing an amide group.
• the blending ratio of the monomer is preferably 0 to 5% by weight, more preferably 0.05 to 5% by weight, and the blending ratio of the monomer containing a cyano group is preferably 0 to 10% by weight. More preferably, it is 0 to 5% by weight, and the proportion of the epoxy group-containing monomer is preferably 0 to 10% by weight, more preferably 0.01 to 5% by weight.
• the polymerizable monomer used for producing the seed particles may be used as the polymerizable monomer used for producing the seed particles.
• the non-crosslinkable monomer which does not have crosslinkability can be used preferably.
• non-crosslinkable monomers include aromatic monovinyl compounds such as styrene, ⁇ -methylstyrene, fluorostyrene, and vinylpyridine; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, Acrylic acid ester monomers such as n-dodecyl acrylate, methoxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Methacrylate monomers such as n-dodecyl acid, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate; conjugated double bond compounds such as butadiene and isoprene; vinyl ester compounds such as vinyl acetate; 4-methyl-1 Such as ⁇ - olefin
• the blending ratio of the non-crosslinkable monomer in the monomer mixture used for producing seed particles is preferably 80 to 99.95% by weight, more preferably 85 to 99.95% by weight, More preferably, it is 90 to 99.95% by weight.
• the seed particles can be produced by polymerizing a monomer mixture containing the above-described polymerizable monomer by emulsion polymerization.
• the seed particles can be obtained as a water dispersion.
• commonly used polymerization auxiliary materials such as emulsifiers, polymerization initiators, molecular weight regulators and the like can be used.
• the conditions for the emulsion polymerization are not particularly limited, but may be set such that the number average particle diameter after the hollow portion forming treatment described later is in the above-described range.
• non-conductive particles can be obtained by subjecting the seed particles to a hollow portion forming treatment so that the BET specific surface area is in the above range.
• a method for performing the hollow portion forming treatment is not particularly limited.
• a seed monomer is prepared by adding a crosslinkable monomer and an organic solvent together with a crosslinking agent to an aqueous dispersion of seed particles.
• the resulting particles after the cross-linking reaction have many cross-linked components on the surface, while there are uncross-linked components inside the particles.
• a core-shell structure in which many remain can be obtained.
• the core portion is removed in the core portion, and a hollow structure is formed in the particles.
• pores are formed by removing the organic solvent swollen in the shell portion.
• the resulting particles after the cross-linking reaction have many components cross-linked on the surface,
• a core-shell structure in which many uncrosslinked components remain in the interior of the particle can be obtained.
• a core part is removed and a hollow structure will be formed in particle
• pores are formed by removing the component swollen in the shell part.
• Diacrylate compounds include polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4-acrylic). Roxypropyloxyphenyl) propane, 2,2′-bis (4-acryloxydiethoxyphenyl) propane, and the like.
• Examples of the triacrylate compound include trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate.
• Examples of the tetraacrylate compound include tetramethylolmethane tetraacrylate.
• Dimethacrylate compounds include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol.
• trimethacrylate examples include dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, and 2,2′-bis (4-methacryloxydiethoxyphenyl) propane.
• trimethacrylate compound examples include trimethylolpropane trimethacrylate and trimethylolethane trimethacrylate.
• the blending amount of the crosslinkable monomer is preferably 100 to 10,000 parts by weight, more preferably 500 to 8,000 parts by weight with respect to 100 parts by weight of the seed particles.
• the size of the hollow portion formed in the obtained polymer particles can be made appropriate.
• the organic solvent used in the method (1) is not particularly limited as long as it can sufficiently swell the seed particles.
• aliphatic hydrocarbons such as hexane; ethylbenzene, xylene, toluene, benzene
• Aromatic hydrocarbons such as carbon tetrachloride, halogenated hydrocarbons such as trichloroethylene and dichloromethane
• Alcohols such as amyl alcohol, butyl alcohol, cyclohexyl alcohol and benzyl alcohol
• Phenols such as cresol
• Ethers such as diethyl ether
• Ketones such as diisobutyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, methyl ethyl ketone, cyclohexanone
• the compounding amount of the organic solvent is preferably 13 to 40 parts by weight, more preferably 14 to 40 parts by weight with respect to 100 parts by weight of the crosslinkable monomer.
• the crosslinking agent used in the method (1) includes persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis ( 2-methyl-N- (2-hydroxyethyl) propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2 Azo compounds such as 2,2'-azobisisobutyronitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylbuta Noate, diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, t-butylperoxyisobutylate Over organic peroxides such as bets and the like.
• persulfates
• the blending amount of the crosslinking agent is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the crosslinkable monomer.
• the seed particles are treated with a crosslinkable monomer, an organic solvent and a crosslinking agent.
• the method for absorbing the crosslinkable monomer, the organic solvent and the crosslinking agent in the seed particles is not particularly limited, but the crosslinkable monomer and the organic solvent are mixed with the crosslinking agent in the aqueous dispersion of the seed particles.
• a method of adding them, preferably stirring them at 50 to 90 ° C. under the conditions of 1 to 10 hours, and the like can be mentioned.
• a known emulsifier surfactant
• the cross-linking monomer, the organic solvent and the cross-linking agent are absorbed by the seed particles, and then the cross-linking reaction is performed.
• the conditions for the crosslinking reaction are not particularly limited and may be appropriately set according to the type and amount of the crosslinking agent to be used.
• the crosslinking temperature is preferably 50 to 90 ° C., and the crosslinking time is preferably 1 to 5 hours. It is.
• non-conductive particles can be obtained by removing uncrosslinked components and organic solvent from the particles after the crosslinking reaction.
• the method for removing the uncrosslinked component and the organic solvent include a method in which steam is passed through an aqueous dispersion of non-conductive particles in a tank (steam aeration method), and a non-conductive particle aqueous method in a multistage tower. Examples include a so-called steam stripping method in which the dispersion and steam are brought into countercurrent contact.
• the multistage stripper method in which the aqueous dispersion is allowed to flow down from the top of the multistage tower and steam is blown from the bottom of the tower can efficiently remove uncrosslinked components and organic solvents.
• uncrosslinked components and organic solvents can be removed by distillation under reduced pressure.
• the crosslinkable monomer used in the method (2) the same monomer as in the above (1) can be used, and the blending amount thereof is preferably 100 with respect to 100 parts by weight of the seed particles. It is ⁇ 10,000 parts by weight, more preferably 500 to 8,000 parts by weight. By setting the blending amount of the crosslinkable monomer in such a range, the size of the hollow portion formed in the obtained polymer particles can be made appropriate.
• the crosslinking agent used in the method (2) the same as the above (1) can be used, and the blending amount thereof is preferably 100 parts by weight of the crosslinkable monomer.
• the amount is 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight.
• a mixed solution containing a crosslinkable monomer, a crosslinking agent, and water is prepared, and seed particles are added to the prepared mixed solution to perform a crosslinking reaction.
• the conditions for the crosslinking reaction are not particularly limited and may be appropriately set according to the type and amount of the crosslinking agent used.
• the crosslinking temperature is preferably 50 to 90 ° C., and the crosslinking time is preferably 1 to 10 hours. It is. In this case, a known emulsifier (surfactant) may be added.
• the particles after the crosslinking reaction are subjected to an alkali swelling treatment using an alkaline aqueous solution.
• the particles after the cross-linking reaction are alkali swollen by dispersing them in an alkali solution so that the solid content is preferably 5 to 40% by weight.
• aqueous alkali solution sodium hydroxide aqueous solution etc. can be used, for example.
• the uncrosslinked component is removed from the particles after the crosslinking reaction by heating preferably at 25 to 90 ° C. for 1 to 5 hours, and then cooled to room temperature.
• non-conductive particles can be obtained.
• the content ratio of non-conductive particles is preferably 70 to 97% by weight, more preferably 80 to 95% by weight.
• Binder As the binder used in the present invention, various binders can be used as long as they have binding properties. However, in the present invention, the obtained porous film has excellent non-conductive particle retention and flexibility. In addition, a (meth) acrylic polymer or a polymer containing a nitrile group is preferable because it is easy to obtain a battery that is stable in redox and has excellent life characteristics.
• the (meth) acrylic polymer used in the present invention is a polymer containing polymerized units of an acrylate ester and / or a methacrylic ester monomer.
• “(Meth) acrylic polymer” means “acrylic polymer and / or methacrylic polymer”, and the same applies to (meth) acrylic acid ester monomers and the like.
• acrylic acid ester and / or methacrylic acid ester monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2 -Acrylic acid alkyl esters such as ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl Methacrylate, pentyl methacrylate, hexyl
• non-carbonyl oxygen is shown because it exhibits lithium ion conductivity by moderate swelling into the electrolyte without eluting into the electrolyte, and in addition, it is difficult to cause bridging aggregation by the polymer in the dispersion of the active material.
• Heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate and lauryl acrylate which are alkyl acrylates having 7 to 13 carbon atoms in the alkyl group bonded to the atom, are preferred, and bonded to a non-carbonyl oxygen atom More preferred are octyl acrylate, 2-ethylhexyl acrylate, and nonyl acrylate having 8 to 10 carbon atoms in the alkyl group.
• the content ratio of the polymer unit of the (meth) acrylic acid ester monomer in the (meth) acrylic polymer is preferably 50 to 98% by weight, more preferably 60 to 97.5% by weight, particularly preferably 70 to 95% by weight. is there.
• the (meth) acrylic polymer used by this invention contains the polymerization unit of another arbitrary monomer in addition to the polymerization unit of a (meth) acrylic acid ester monomer.
• the polymerization unit of an arbitrary monomer include a polymerization unit of a vinyl monomer having an acidic group, a polymerization unit of a monomer having a crosslinkable group, and the like.
• Examples of the vinyl monomer having an acidic group include a monomer having a carboxylic acid group, a monomer having a hydroxyl group, a monomer having a sulfonic acid group, a monomer having a —PO 3 H 2 group, and —PO (OH ) (OR) group (R represents a hydrocarbon group) and a monomer having a lower polyoxyalkylene group.
• generates a carboxylic acid group by a hydrolysis can be used similarly.
• Examples of the monomer having a carboxylic acid group include monocarboxylic acid, dicarboxylic acid, dicarboxylic acid anhydride, and derivatives thereof.
• Monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid , ⁇ -diaminoacrylic acid and the like.
• Dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, methylallyl maleate, diphenylmaleate, nonylmaleate, And maleate esters such as decyl maleate, dodecyl maleate, octadecyl maleate and fluoroalkyl maleate.
• Examples of the acid anhydride of dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
• Examples of the monomer having a hydroxyl group include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol and 5-hexen-1-ol; 2-hydroxyethyl acrylate, acrylic acid-2 Ethylenic acid such as hydroxypropyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate, di-2-hydroxypropyl itaconate Alkanol esters of unsaturated carboxylic acids; general formula CH 2 ⁇ CR 1 —COO— (CnH 2 nO) m—H (m is an integer from 2 to 9, n is an integer from 2 to 4, R 1 is hydrogen or methyl An ester of a polyalkylene glycol represented by the following formula: (meth) acrylic acid; Mono (meth) acrylic esters of dihydroxy esters of dicarboxylic acids such as til-2 ′-(
• Examples of monomers having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methyl. Examples thereof include propanesulfonic acid and 3-allyloxy-2-hydroxypropanesulfonic acid.
• Monomers having a —PO 3 H 2 group and / or —PO (OH) (OR) group include 2- (meth) acryloyloxyethyl phosphate, methyl phosphate Examples include -2- (meth) acryloyloxyethyl and ethyl phosphate- (meth) acryloyloxyethyl.
• Examples of the monomer having a lower polyoxyalkylene group include poly (alkylene oxide) such as poly (ethylene oxide).
• a monomer having a carboxylic acid group is preferable from the viewpoint that the binding force can be further increased, and among them, a monocarboxylic acid having 5 or less carbon atoms having a carboxylic acid group such as acrylic acid and methacrylic acid, and the like.
• Dicarboxylic acids having 5 or less carbon atoms having two carboxylic acid groups per molecule such as maleic acid and itaconic acid are preferred.
• the content of the polymer units of the vinyl monomer having an acidic group is preferably 1.0 to 3.0% by weight, more preferably 1.5 to 2.5% by weight.
• Monomers having a crosslinkable group include a crosslinkable group, a monofunctional monomer having one olefinic double bond per molecule, and a polyfunctional having two or more olefinic double bonds per molecule.
• the crosslinkable group contained in the monofunctional monomer having a crosslinkable group and one olefinic double bond per molecule is selected from the group consisting of an epoxy group, an N-methylolamide group, an oxetanyl group, and an oxazoline group. At least one selected from the above is preferable, and an epoxy group is more preferable in terms of easy crosslinking and adjustment of the crosslinking density.
• Examples of the monomer containing an epoxy group contained in the monomer having a crosslinkable group include a monomer containing a carbon-carbon double bond and an epoxy group and a monomer containing a halogen atom and an epoxy group. It is done.
• Examples of the monomer containing a carbon-carbon double bond and an epoxy group include unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl ether; butadiene monoepoxide, Diene or polyene monoepoxides such as chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene; Alkenyl epoxides such as epoxy-1-butene, 1,
• Examples of the monomer having a halogen atom and an epoxy group include epihalohydrin such as epichlorohydrin, epibromohydrin, epiiodohydrin, epifluorohydrin, ⁇ -methylepichlorohydrin; p-chlorostyrene oxide; dibromo Phenyl glycidyl ether;
• Examples of the monomer containing an N-methylolamide group include (meth) acrylamides having a methylol group such as N-methylol (meth) acrylamide.
• Monomers containing an oxetanyl group include 3-((meth) acryloyloxymethyl) oxetane, 3-((meth) acryloyloxymethyl) -2-trifluoromethyloxetane, and 3-((meth) acryloyloxymethyl). ) -2-phenyloxetane, 2-((meth) acryloyloxymethyl) oxetane, 2-((meth) acryloyloxymethyl) -4-trifluoromethyloxetane, and the like.
• Monomers containing an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2- Examples thereof include oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like.
• Polyfunctional monomers having two or more olefinic double bonds per molecule include allyl acrylate or allyl methacrylate, trimethylolpropane-triacrylate, trimethylolpropane-methacrylate, dipropylene glycol diallyl ether, polyglycol diallyl Ethers, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, or other allyl or vinyl ethers of polyfunctional alcohols, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane-diallyl ether, methylenebisacrylamide and / or Or divinylbenzene is preferable.
• allyl acrylate, allyl methacrylate, trimethylolpropane-triacrylate and / or trimethylolpropane-methacrylate and the like can be mentioned.
• crosslinking density is easily improved, a polyfunctional monomer having two or more olefinic double bonds per molecule is preferable, and further, the crosslinking density is improved and the copolymerization property is high. For this reason, acrylates or methacrylates having an allyl group such as allyl acrylate or allyl methacrylate are preferred.
• the content of the polymer units of the monomer having a crosslinkable group is preferably 0.01 to 2.0% by weight, more preferably 0.05 to 1.5% by weight. %, Particularly preferably in the range of 0.1 to 1.0% by weight.
• the (meth) acrylic polymer used in the present invention may contain a polymer unit based on a monomer copolymerizable therewith in addition to the polymer unit based on the monomer described above.
• Monomers copolymerizable with these include halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate; methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether Vinyl ethers such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, isopropenyl vinyl ketone and the like; heterocycle-containing vinyl compounds such as N-vinyl pyrrolidone, vinyl pyridine and vinyl imidazole; acrylamide; Is mentioned.
• the (meth) acrylic polymer used in the present invention can be produced by polymerizing the above monomers.
• the polymerization method any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used.
• the polymerization reaction any reaction such as ionic polymerization, radical polymerization, and living radical polymerization can be used.
• polymerization initiator used for the polymerization examples include lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, 3,3,5-trimethylhexanoyl peroxide, and the like.
• the polymer containing a nitrile group used in the present invention is not particularly limited as long as it contains a nitrile group.
• a homopolymer of an unsaturated nitrile monomer an unsaturated nitrile monomer And copolymers with other monomers copolymerizable with the polymer.
• the unsaturated nitrile monomer is not limited as long as it is an unsaturated compound having a nitrile group, such as acrylonitrile; ⁇ -halogenoacrylonitrile such as ⁇ -chloroacrylonitrile and ⁇ -bromoacrylonitrile; methacrylonitrile, ethacrylonitrile, etc. ⁇ -alkylacrylonitrile; and the like.
• acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is particularly preferable.
• the content of unsaturated nitrile monomer units in the nitrile group-containing polymer used in the present invention is preferably 1 to 100% by weight, more preferably 1 to 50% by weight.
• Examples of other copolymerizable monomers include conjugated diene monomers, unsaturated monocarboxylic acid monomers, unsaturated carboxylic acid ester monomers, unsaturated dicarboxylic acid monoester monomers, Examples include unsaturated polyvalent carboxylic acid monomers and aromatic vinyl monomers.
• Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and the like.
• Examples of the unsaturated monocarboxylic acid monomer include acrylic acid, methacrylic acid, and crotonic acid.
• Examples of unsaturated carboxylic acid ester monomers include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, n-pentyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, and propyl methacrylate. Can be mentioned.
• Examples of unsaturated dicarboxylic acid monoester monomers include monomethyl maleate, monoethyl maleate, monopropyl maleate, mono n-butyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, mono n-fumarate Examples include butyl.
• Examples of the unsaturated polyvalent carboxylic acid monomer include itaconic acid, fumaric acid and maleic acid.
• Examples of the aromatic vinyl monomer include styrene, ⁇ -methylstyrene, vinyl pyridine and the like.
• the nitrile group-containing polymer used in the present invention is produced by polymerizing an unsaturated nitrile monomer alone or with another monomer copolymerizable with the unsaturated nitrile monomer. be able to.
• the polymerization method any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used.
• the polymerization reaction any reaction such as ionic polymerization, radical polymerization, and living radical polymerization can be used.
• polymerization the thing similar to the (meth) acrylic polymer mentioned above can be used, for example.
• the polymer containing a nitrile group used in the present invention is a nitrile rubber containing at least an unsaturated nitrile monomer unit and a conjugated diene monomer unit
• an aliphatic carbon-carbon Hydrogenated nitrile rubber may be obtained by hydrogenating unsaturated bonds.
• the binder content is preferably 3 to 20% by weight, more preferably 3 to 15% by weight.
• the ratio of the content of non-conductive particles and the content of the binder is a weight ratio of “non-conductive particle weight / binder weight for porous membrane”. It is preferably in the range of 2 to 100, and more preferably in the range of 10 to 100. By setting these weight ratios within such a range, it is possible to maintain both high-temperature short-circuit resistance and excellent cycle characteristics.
• the binder used in the present invention is usually prepared and stored as a dispersion in the form of particles dispersed in a dispersion medium.
• a dispersion medium it is preferable to use water from the viewpoint of low environmental load and high drying speed.
• an organic solvent such as N-methylpyrrolidone (NMP) can be used.
• the number average particle diameter (dispersion particle diameter) of the binder is preferably 50 to 500 nm, more preferably 70 to 400 nm, and still more preferably 100 to 250 nm. is there.
• the number average particle diameter of the binder is in such a range, the strength and flexibility of the obtained porous film are good.
• the content of the binder in the dispersion is preferably 15 to 70% by weight, more preferably 20 to 65% by weight.
• the content ratio of the binder is within such a range, workability in manufacturing a porous membrane slurry for a secondary battery, which will be described later, can be improved.
• the glass transition temperature (Tg) of the binder used in the present invention is preferably ⁇ 50 to 25 ° C., more preferably ⁇ 45 to 15 ° C., and particularly preferably ⁇ 40 to 5 ° C.
• Tg of the binder is in such a range, the resulting porous film can have excellent strength and flexibility.
• the porous membrane for a secondary battery of the present invention may contain a heavy metal capturing compound.
• a heavy metal capturing compound By containing the heavy metal capturing compound, when the porous membrane for a secondary battery of the present invention is used for a secondary battery, it is possible to capture transition metal ions that elute in the electrolyte during charge / discharge of the secondary battery. Therefore, it is possible to prevent a decrease in cycle characteristics and safety of the secondary battery due to the transition metal ions.
• the heavy metal scavenging compound is not particularly limited as long as it has a heavy metal scavenging function, but preferably from the group consisting of an aminocarboxylic acid chelate compound, a phosphonic acid chelate compound, gluconic acid, citric acid, malic acid and tartaric acid. Selected. Among these, chelate compounds that can selectively capture transition metal ions without capturing lithium ions are used, and aminocarboxylic acid chelate compounds and phosphonic acid chelate compounds are particularly preferably used.
• aminocarboxylic acid chelate compounds include ethylenediaminetetraacetic acid (hereinafter sometimes referred to as “EDTA”), nitrilotriacetic acid (hereinafter sometimes referred to as “NTA”), trans-1,2-diamino.
• EDTA ethylenediaminetetraacetic acid
• NTA nitrilotriacetic acid
• trans-1,2-diamino trans-1,2-diamino.
• Cyclohexanetetraacetic acid hereinafter sometimes referred to as “DCTA”
• DCTA diethylene-triaminepentaacetic acid
• DTPA diethylene-triaminepentaacetic acid
• EGTA bis- (aminoethyl) glycol ether-N, N, N ', N'-tetraacetic acid
• HEDTA N- (2-hydroxyethyl) ethylenediamine-N, N ′, N′-triacetic acid
• DHEG dihydroxyethylglycine
• HEDP 1-hydroxyethane-1,1-diphosphonic acid
• the compounding amount of the heavy metal capturing compound is preferably 0.001 to 1.0 part by weight, more preferably 0.005 to 0.5 part by weight, and particularly preferably 0.01 to 0.00 part by weight with respect to 100 parts by weight of the binder. 3 parts by weight.
• the porous membrane for a secondary battery of the present invention may contain arbitrary components.
• optional components include dispersants, leveling agents, antioxidants, binders other than the binders described above, thickeners, antifoaming agents, and electrolytic solution additives having functions such as suppression of electrolytic solution decomposition. And the like.
• dispersant examples include anionic compounds, cationic compounds, nonionic compounds, and polymer compounds.
• a dispersing agent is selected according to the nonelectroconductive particle to be used.
• the content ratio of the dispersing agent in the porous film is preferably within a range that does not affect the battery characteristics, and specifically 10% by weight or less.
• leveling agents include surfactants such as alkyl surfactants, silicon surfactants, fluorosurfactants, and metal surfactants. By mixing such surfactants, coating is possible. It is possible to prevent repelling that sometimes occurs and to improve the smoothness of the porous membrane.
• antioxidants examples include a phenol compound, a hydroquinone compound, an organic phosphorus compound, a sulfur compound, a phenylenediamine compound, and a polymer type phenol compound.
• the polymer type phenol compound is a polymer having a phenol structure in the molecule, and a polymer type phenol compound having a weight average molecular weight of 200 to 1000, preferably 600 to 700 is preferably used.
• PTFE polytetrafluoroethylene
• polyacrylic acid derivatives polyacrylonitrile derivatives
• soft polymers soft polymers
• thickeners include cellulosic polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (modified) poly (meth) acrylic acid and ammonium salts and alkali metal salts thereof; ) Polyvinyl alcohols such as polyvinyl alcohol, copolymers of acrylic acid or acrylate and vinyl alcohol, maleic anhydride or copolymers of maleic acid or fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified Examples thereof include polyacrylic acid, oxidized starch, phosphoric acid starch, casein, various modified starches, acrylonitrile-butadiene copolymer hydride, and the like.
• cellulosic polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (modified) poly (meth) acrylic acid and ammonium salt
• the content ratio of these optional components in the porous membrane for a secondary battery of the present invention is preferably in a range that does not affect the battery characteristics, specifically, preferably 10% by weight or less,
• the total content of the arbitrary components to be blended is preferably 40% by weight or less, more preferably 20% by weight or less.
• the porous membrane for a secondary battery of the present invention is obtained by, for example, (1) obtaining a porous membrane slurry for a secondary battery containing non-conductive particles, a binder and a dispersion medium, A method of forming a slurry layer by coating on a base material of the substrate, and then drying the slurry layer; (2) obtaining a porous membrane slurry for a secondary battery containing non-conductive particles, a binder and a dispersion medium, And a method of drying the substrate after immersing the substrate in the porous membrane slurry.
• the porous membrane slurry for a secondary battery is a composition containing the above-described non-conductive particles, the above-described binder, the dispersion medium, and any of the above-described optional components that are added as necessary.
• the dispersion medium is not particularly limited as long as it can disperse non-conductive particles, a binder, and optional components uniformly, and an organic solvent can be used in addition to water.
• organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as acetone, ethyl methyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane, and ethylcyclohexane.
• Chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; Esters such as ethyl acetate, butyl acetate, ⁇ -butyrolactone and ⁇ -caprolactone; Acylonitriles such as acetonitrile and propionitrile; Tetrahydrofuran, Ethers such as ethylene glycol diethyl ether: alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl And amides such as lupyrrolidone and N, N-dimethylformamide.
• These dispersion media may be used alone, or two or more of these dispersion media may be mixed and used as a mixed medium.
• these those having particularly excellent non-conductive particle dispersibility, low boiling point and high volatility are preferable.
• acetone, toluene, cyclohexanone, cyclopentane, tetrahydrofuran, cyclohexane, xylene, water, N— Methyl pyrrolidone and the like are preferable.
• the solid content concentration in the porous membrane slurry for a secondary battery can be appropriately adjusted to such a concentration that the viscosity of the slurry composition can be applied and immersed and has fluidity. However, it is generally about 10 to 50% by weight.
• the component other than the solid component is a component that volatilizes in the drying process, and includes, in addition to the dispersion medium, for example, a medium in which these are dissolved or dispersed during the preparation of the non-conductive particles and the binder. It is.
• the method for preparing the porous membrane slurry for the secondary battery is not particularly limited, and by mixing the above-described non-conductive particles, the above-mentioned binder, the dispersion medium, and any of the above-described optional components added as necessary. Obtainable.
• the mixing method and mixing order in mixing these are not particularly limited.
• the mixing device is not particularly limited as long as it can uniformly mix the above-described components, and includes a homomixer, ball mill, sand mill, pigment disperser, crusher, ultrasonic disperser, homogenizer, planetary mixer, etc. However, it is particularly preferable to use a homomixer from the viewpoint that an appropriate dispersion share can be added.
• the viscosity of the porous membrane slurry for a secondary battery is preferably 10 mPa ⁇ S to 10,000 mPa ⁇ S, more preferably 50 to 500 mPa ⁇ s, from the viewpoints of uniform coatability and slurry aging stability.
• the viscosity can be measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
• the porous membrane for a secondary battery of the present invention may be, for example, one that can maintain the shape as a membrane independently of the one that maintains the shape as a membrane while being supported by a substrate. It is preferable that the substrate is supported by the substrate, that is, is formed into a film on the substrate to form a composite.
• a base material for forming a porous film for a secondary battery it is particularly preferable to use a constituent element in the secondary battery, specifically, an electrode (positive electrode or negative electrode) or an organic separator as the base material. preferable. That is, it is particularly preferable to use an electrode or an organic separator as a base material, and form the porous membrane for a secondary battery of the present invention thereon.
• the secondary battery porous membrane of the present invention when the secondary battery porous membrane of the present invention is formed on a substrate other than an electrode or an organic separator, the secondary battery porous membrane is peeled off from the substrate and assembled into a secondary battery. It can be used by stacking on top or on an organic separator. In addition, a well-known peeling film etc. can be used as base materials other than an electrode and an organic separator.
• the method for forming a slurry layer by applying a porous membrane slurry for a secondary battery onto a substrate is not particularly limited.
• methods such as brushing and brushing.
• the dipping method and the gravure method are preferable from the viewpoint that a uniform porous film for a secondary battery can be obtained.
• Examples of the method for drying the slurry layer obtained by coating include drying by warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams.
• the drying temperature may be set according to the type of the dispersion medium to be used. For example, in the case of using a low-volatility dispersion medium such as N-methylpyrrolidone, the temperature is higher than 120 ° C. with a blower dryer. It is preferable to dry. Alternatively, when a highly volatile dispersion medium is used, it can be dried at a low temperature of 100 ° C. or lower. In addition, when forming the porous film for secondary batteries on an organic separator, since it is necessary to dry without causing shrinkage of an organic separator, drying at a low temperature of 100 ° C. or less is preferable.
• a press using a die press or a roll press is used as necessary. Processing may be performed.
• the film thickness of the porous membrane for a secondary battery of the present invention is not particularly limited, but is preferably 1 to 10 ⁇ m, more preferably 2 to 7 ⁇ m. By setting the film thickness in such a range, the effect of forming the porous film for the secondary battery of the present invention can be appropriately obtained while keeping the capacity per volume (weight) of the obtained secondary battery high. .
• the electrode for a secondary battery of the present invention is formed by laminating a current collector, an electrode active material layer, and the above-described porous film for a secondary battery of the present invention in this order.
• the secondary battery electrode of the present invention is, for example, made of an electrode composed of a current collector and an electrode active material layer as a base material, and the secondary battery porous film slurry is used on the electrode. It can be manufactured by forming a porous film.
• the porous membrane for a secondary battery of the present invention is formed on a substrate other than an electrode, and the obtained porous membrane for a secondary battery is peeled from the substrate, and this is used as a current collector and an electrode active material layer
• the secondary battery electrode of the present invention can also be obtained by laminating the electrodes on the electrode.
• the current collector is not particularly limited as long as it is an electrically conductive and electrochemically durable material. From the viewpoint of heat resistance, for example, iron, copper, aluminum, nickel, stainless steel, and the like. Metal materials such as titanium, tantalum, gold, and platinum can be preferably used. Among these, aluminum is particularly preferable for the positive electrode of the lithium ion secondary battery, and copper is particularly preferable for the negative electrode of the lithium ion secondary battery.
• the shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 to 0.5 mm is preferable.
• the electrode active material layer usually contains an electrode active material and a binder for the electrode active material layer, and may contain a conductivity imparting material, a reinforcing material, and the like as necessary.
• the electrode active material for forming the electrode active material layer is not particularly limited, but when the secondary battery electrode of the present invention is used for a positive electrode of a lithium ion secondary battery, the following inorganic compound A positive electrode active material made of or a positive electrode active material made of an organic compound can be used.
• 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.
• transition metal Fe, Co, Ni, Mn and the like are used.
• Specific examples of the inorganic compound 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 It is done. These compounds may be partially element-substituted.
• a conductive polymer compound such as polyacetylene or poly-p-phenylene
• examples of the electrode active material for forming the electrode active material layer include amorphous carbon, graphite, and natural graphite.
• Carbonaceous materials such as mesocarbon microbeads and pitch-based carbon fibers, and conductive polymer compounds such as polyacene can be used.
• metals such as silicon, tin, zinc, manganese, iron and nickel, alloys thereof, oxides and sulfates of the metals or alloys, metal lithium, Li—Al, Li—Bi—Cd Lithium alloys such as Li—Sn—Cd, lithium transition metal nitrides, silicon and the like can also be used.
• nickel hydroxide particles or the like are used as the electrode active material for forming the electrode active material layer.
• the nickel hydroxide particles may be solid-solved with cobalt, zinc, cadmium, or the like, or may be coated with a cobalt compound whose surface is subjected to an alkali heat treatment.
• nickel hydroxide particles include cobalt compounds such as cobalt oxide, metal cobalt and cobalt hydroxide, zinc compounds such as metal zinc, zinc oxide and zinc hydroxide, and rare earth compounds such as erbium oxide.
• the additive may be contained.
• hydrogen storage alloy particles may be used as the electrode active material for forming the electrode active material layer. It can.
• the hydrogen storage alloy particles are not particularly limited as long as they can store hydrogen generated electrochemically in an alkaline electrolyte during battery charging and can easily release the stored hydrogen during discharge.
• AB 5 type system preferably particles made of TiNi system and TiFe system hydrogen absorbing alloy.
• hydrogen storage having a composition represented by the general formula: L m Ni w Co x Mn y Al z (the total value of the atomic ratios w, x, y, z is 4.80 ⁇ w + x + y + z ⁇ 5.40)
• the alloy particles are suitable because the pulverization accompanying the progress of the charge / discharge cycle is suppressed and the charge / discharge cycle life is improved.
• the binder for the electrode active material layer for forming the electrode active material layer various resin components can be used.
• polyethylene polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, polyacrylonitrile derivatives, and the like can be used.
• the soft polymer illustrated below can also be used as a binder for electrode active material layers. That is, polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer, etc.
• An acrylic soft polymer which is a homopolymer of acrylic acid or a methacrylic acid derivative, or a copolymer of monomers copolymerizable therewith;
• Isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
• Olefinic soft polymers of Vinyl-based soft polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, vinyl acetate / styrene copolymer; Epoxy-based soft polymers such as polyethylene oxide, polypropylene oxide, epichlorohydrin rubber; Fluorine-containing soft polymers such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber; Other soft polymers such as natural rubber, polypeptide, protein, polyester-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, and the like can also be used.
• the electrode active material layer may contain a conductivity imparting material or a reinforcing material as necessary.
• the conductivity imparting material include graphite, acetylene black, ketjen black, carbon black, graphite, vapor grown carbon fiber, and conductive carbon such as carbon nanotube.
• the reinforcing material include various inorganic and organic spherical, plate-like, rod-like, or fibrous fillers.
• the electrode active material layer is usually an electrode slurry obtained by dispersing an electrode active material, a binder for the electrode active material layer, and a conductivity-imparting material and a reinforcing material added as necessary in a dispersion medium. Can be formed on the current collector and dried as necessary.
• an organic solvent can be used in addition to water.
• organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as ethyl methyl ketone and cyclohexanone; ethyl acetate, butyl acetate, ⁇ -butyrolactone, ⁇ -Esters such as caprolactone; Acylonitriles such as acetonitrile and propionitrile; Ethers such as tetrahydrofuran and ethylene glycol diethyl ether: Alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl Amides such as pyrrolidone and N, N-dimethylformamide may be mentioned. These media can be used alone or in combination of two or more,
• the electrode slurry is prepared by mixing the electrode active material, the binder for the electrode active material layer, and the conductivity-imparting material and reinforcing material added as necessary, and the dispersion medium using a mixer. can get.
• a mixer a ball mill, sand mill, pigment disperser, crusher, ultrasonic disperser, homogenizer, planetary mixer, Hobart mixer, etc. can be used. It is preferable because aggregation of the resin can be suppressed.
• the separator for a secondary battery of the present invention is formed by laminating the organic separator and the above-described porous film for a secondary battery of the present invention.
• the separator for a secondary battery of the present invention is produced, for example, by forming the porous film for a secondary battery of the present invention on the organic separator as a base material and using the porous film slurry for the secondary battery thereon. be able to.
• the porous membrane for a secondary battery of the present invention is formed on a substrate other than the organic separator, the obtained porous membrane for a secondary battery is peeled from the substrate, and this is laminated on the organic separator.
• the separator for a secondary battery of the present invention can also be obtained.
• the porous film for secondary batteries may be formed only in the single side
• organic separator a known separator comprising a polyolefin resin such as polyethylene or polypropylene, or an aromatic polyamide resin can be used.
• a porous membrane having high resistance and a fine pore diameter can be preferably used.
• organic separators include microporous membranes made of polyolefin resins (polyethylene, polypropylene, polybutene, polyvinyl chloride), and mixtures or copolymers thereof, polyethylene terephthalate, polycycloolefins, polyethers, and the like.
• Microporous membrane made of resin such as sulfone, polyamide, polyimide, polyimide amide, polyaramid, polycycloolefin, nylon, polytetrafluoroethylene or the like, or non-woven fabric, aggregate of insulating substance particles Etc.
• resin such as sulfone, polyamide, polyimide, polyimide amide, polyaramid, polycycloolefin, nylon, polytetrafluoroethylene or the like, or non-woven fabric, aggregate of insulating substance particles Etc.
• the coating property of the porous membrane slurry for the secondary battery is excellent, and the film thickness of the entire separator can be reduced, thereby increasing the active material ratio in the secondary battery and increasing the capacity per volume.
• a microporous film made of a polyolefin-based resin is preferable because it can be used.
• the thickness of the organic separator is preferably 0.5 to 40 ⁇ m, more preferably 1 to 35 ⁇ m, and still more preferably 5 to 30 ⁇ m. When the thickness is in such a range, the resistance due to the organic separator in the secondary battery can be reduced while the coating property to the organic separator is good.
• examples of the polyolefin resin used as the material for the organic separator include homopolymers such as polyethylene and polypropylene, copolymers, and mixtures thereof.
• examples of the polyethylene include low density, medium density, and high density polyethylene, and high density polyethylene is preferable from the viewpoint of piercing strength and mechanical strength. These polyethylenes may be used in combination of two or more for the purpose of imparting flexibility.
• the polymerization catalyst used for these polyethylenes is not particularly limited, and examples thereof include Ziegler-Natta catalysts, Phillips catalysts, and metallocene catalysts.
• the viscosity average molecular weight of polyethylene used as the material for the organic separator is preferably 100,000 to 12 million, more preferably 200,000 to 3 million, from the viewpoint of achieving both mechanical strength and high permeability.
• examples of polypropylene include homopolymers, random copolymers, and block copolymers, and one kind or a mixture of two or more kinds can be used.
• the polymerization catalyst is not particularly limited, and examples thereof include Ziegler-Natta catalysts and metallocene catalysts.
• the stereoregularity is not particularly limited, and isotactic, syndiotactic or atactic can be used. However, it is desirable to use isotactic polypropylene because it is inexpensive.
• a known method can be employed. For example, after forming a melt-extruded film of polypropylene and polyethylene, annealing at low temperature to grow a crystal domain, stretching in this state, and extending the amorphous region to form a microporous film; hydrocarbon After mixing a solvent or other low molecular weight material with polypropylene or polyethylene, a film is formed, and then a film in which the solvent or low molecular weight has gathered in the amorphous phase and has started to form an island phase is used. And a wet method in which a microporous film is formed by removing using a solvent that easily volatilizes.
• the organic separator used in the present invention may contain any filler or fiber compound for the purpose of controlling strength, hardness, and heat shrinkage rate.
• the organic separator used in the present invention is preliminarily prepared with a low molecular compound or a high molecular weight compound. Coating treatment with a molecular compound, electromagnetic radiation treatment such as ultraviolet rays, or plasma treatment such as corona discharge / plasma gas may be performed.
• a polymer compound containing a polar group such as a carboxylic acid group, a hydroxyl group, and a sulfonic acid group because it has a high impregnation property with an electrolytic solution and is easy to obtain adhesion with a porous membrane for a secondary battery. It is preferable.
• the secondary battery of the present invention includes a positive electrode, a negative electrode, a separator, and an electrolyte, and includes the above-described porous membrane for a secondary battery of the present invention in at least one of the positive electrode, the negative electrode, and the separator. That is, the secondary battery of this invention is comprised using the electrode for secondary batteries or the separator for secondary batteries of this invention mentioned above as at least any one of a positive electrode, a negative electrode, or a separator.
• Examples of the secondary battery of the present invention include a lithium ion secondary battery, a nickel-hydrogen secondary battery, etc., but there is a high demand for improving safety and the introduction effect of the porous film for a secondary battery of the present invention is high.
• To lithium ion secondary batteries are preferred.
• the case where it uses for a lithium ion secondary battery is illustrated and demonstrated.
• an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is used as the electrolytic solution for the lithium ion secondary battery.
• a lithium salt is used as the supporting electrolyte.
• the lithium salt is not particularly limited, 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.
• the organic solvent used in the electrolyte for the lithium ion secondary battery is not particularly limited as long as it can dissolve the supporting electrolyte, but dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC).
• Carbonates such as propylene carbonate (PC), butylene carbonate (BC), and methyl ethyl carbonate (MEC); esters such as ⁇ -butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfolane, Sulfur-containing compounds such as dimethyl sulfoxide are preferably used.
• a positive electrode and a negative electrode are overlapped via a separator, and this is wound into a battery container according to the shape of the battery.
• the method of injecting and sealing is mentioned.
• the shape of the secondary 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 secondary battery of the present invention thus obtained comprises the porous film for a secondary battery of the present invention described above, the excellent characteristics of the porous film for a secondary battery of the present invention, that is, the film thickness High uniformity, high-temperature short-circuit resistance (reliability in high-temperature environments), and excellent ion permeability, high reliability in high-temperature environments, and excellent cycle and rate characteristics is there.
• the BET specific surface area of the non-conductive particles was measured by a gas adsorption method using a fully automatic BET specific surface area measuring device (product name “Macsorb HM model-1208”, manufactured by Mountec Co., Ltd.).
• ⁇ Number average particle size of non-conductive particles, coefficient of variation of particle size> 100 particles are arbitrarily selected from SEM photographs taken at 25,000 times magnification with an electron microscope, the longest side of the particle image is a, the shortest side is b, and (a + b) / 2 was calculated for each particle to determine the particle diameter of each particle, and the number average particle diameter was calculated as the arithmetic average value of the determined particle diameters.
• the standard deviation was calculated for the number average particle diameter, and the coefficient of variation of the particle diameter was calculated based on the number average particle diameter and the standard deviation.
• Non-conductive particles 100 particles are arbitrarily selected from SEM photographs taken at a magnification of 25000 times with an electron microscope, and the circumference of a circle having the same projected area as the particle image is L 0 .
• L 0 / L was defined as the circularity
• the average circularity was calculated from the average of 100 pieces.
• EC ethylene carbonate
• DEC diethyl carbonate
• the laminate obtained above was sealed in a 2032 type coin cell, a lead wire was taken from the coin cell, and a thermocouple was attached and placed in an oven. While applying an alternating current with an amplitude of 10 mV and a frequency of 1 kHz, the temperature was raised to 200 ° C. at a temperature rising rate of 1.6 ° C./min, and the cell resistance during this time was measured to confirm the occurrence of a short circuit. In this test, as the temperature rises, the resistance value increases due to shutdown, the resistance value becomes at least 1000 ⁇ / cm 2 or more, and then the resistance value rapidly decreases to 10 ⁇ / cm 2 or less. In some cases, a short circuit occurred. This test was performed on 20 samples and evaluated according to the following criteria.
• Electrode with porous membrane An organic separator (single-layer polypropylene separator, porosity 55%, thickness 25 ⁇ m) is punched into a 19 mm diameter circle and immersed in a 3% by weight methanol solution of a nonionic surfactant (Emulgen 210P, manufactured by Kao Corporation). And air dried. Separately, the electrode with a porous film to be measured is punched into a circle having a diameter of 19 mm, a circular organic separator and a circular electrode with a porous film are impregnated with an electrolyte, and these are overlapped to form a pair of circles.
• a nonionic surfactant Emulgen 210P
• a full-cell coin type lithium ion secondary battery is charged to 4.2 V by a constant current method of 0.1 C, and then discharged to 3.0 V at 0.1 C to obtain a discharge capacity of 0.1 C. It was. Subsequently, it charged to 4.2V at 0.1C, discharged to 3.0V at 1C, and calculated
• These measurements are performed on 10 cells of a full-cell coin-type lithium ion secondary battery, and the average value of each measurement value is 0.1 C for the discharge capacity of 0.1 C and 1 C for the discharge capacity of 1 C.
• Example 1 Manufacture of seed polymer particles>
• a reactor equipped with a stirrer 93.8 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 1 part of allyl glycidyl ether, 1 part of N-methylolacrylamide, 122 parts of ion-exchanged water, and 0.
• Two parts were added and polymerized at 70 ° C. for 6 hours.
• an aqueous dispersion of seed polymer particles (A-1) having an average particle diameter of 400 nm was obtained.
• ⁇ Binder production> In a reactor equipped with a stirrer, 70 parts of ion-exchanged water, 0.4 part of sodium dodecylbenzenesulfonate and 0.3 part of potassium persulfate were added and mixed to obtain a mixture A, which was obtained at 60 ° C. The temperature was raised to. On the other hand, in a separate container, 50 parts of ion exchanged water, 0.8 part of sodium dodecylbenzenesulfonate, 77.7 parts of 2-ethylhexyl acrylate, 19.85 parts of acrylonitrile, 2 parts of methacrylic acid, and 0.2 parts of allyl methacrylate Parts were mixed to obtain a monomer mixture.
• the obtained monomer mixture was polymerized by adding continuously in the mixture A obtained above over 4 hours.
• the polymerization reaction was carried out by maintaining the temperature of the reaction system at 60 ° C. Then, after the addition of the monomer mixture was completed, the reaction was further continued at 70 ° C. for 3 hours to obtain an aqueous dispersion containing the acrylic polymer binder (C-1).
• composition of the obtained acrylic polymer binder (C-1) was as follows: 2-ethylhexyl acrylate unit 77.9%, acrylonitrile unit 19.9%, methacrylic acid unit 2%, and allyl methacrylate unit 0.2%. there were.
• the resulting mixture is mixed with 1.0 part of carboxymethyl cellulose and water as a dispersion medium, and mixed with a planetary mixer to obtain a slurry for a negative electrode.
• a single-layer polypropylene organic separator (porosity 55%, thickness 25 ⁇ m) produced by a dry method was prepared, and the slurry for the porous membrane obtained above was prepared on one surface of the polypropylene organic separator.
• the slurry layer was formed by apply
• the formed slurry layer was dried at 50 ° C. for 10 minutes to form a porous film. And the same operation was performed also on the other surface of the organic separator made of polypropylene, whereby a porous film was formed in the same manner, and an organic separator with a porous film having a porous film on both surfaces was obtained.
• the positive electrode, the negative electrode, and the organic separator with a porous film obtained above were cut into circles with diameters of 13 mm, 14 mm, and 18 mm, respectively, and on the inner bottom surface of a stainless steel coin-type outer container provided with polypropylene packing.
• a circular positive electrode with a diameter of 13 mm, an organic separator with a porous film with a diameter of 18 mm, and a circular negative electrode with a diameter of 14 mm were laminated in this order, and these were stored in a coin-type outer container.
• the positive electrode was placed so that the surface on the aluminum foil side faced the bottom surface side of the outer container, and the surface on the positive electrode active material layer side faced the organic separator with a porous film. Further, the negative electrode was placed so that the surface on the negative electrode active material layer side faced toward the organic separator with a porous film and the surface on the copper foil side faced upward.
• a full cell coin-type lithium ion secondary battery (coin cell CR2032) having a diameter of 20 mm and a thickness of about 3.2 mm was manufactured.
• EC ethylene carbonate
• DEC diethyl carbonate
• LiPF 6 1 mol / liter concentration
• Example 2 Manufacture of seed polymer particles> In the same manner as in Example 1, seed polymer particles (A-1) were obtained.
• Example 3 Manufacture of non-conductive particles> Except that the blending amount of ethylene glycol dimethacrylate was changed from 83.3 parts to 85.7 parts and the blending amount of toluene was changed from 16.7 parts to 14.3 parts, An aqueous dispersion of polymer particles (B-3) having an average particle diameter of 700 nm was obtained. The polymer particles (B-3) thus obtained were measured for BET specific surface area, particle size variation coefficient, and average circularity. The results are shown in Table 1.
• Example 4 ⁇ Manufacture of non-conductive particles> The number average particle size was the same as in Example 1 except that the blending amount of ethylene glycol dimethacrylate was changed from 83.3 parts to 75 parts and the blending amount of toluene was changed from 16.7 parts to 25 parts. An aqueous dispersion of polymer particles (B-4) having a diameter of 700 nm was obtained. The polymer particles (B-4) thus obtained were measured for BET specific surface area, particle size variation coefficient, and average circularity. The results are shown in Table 1.
• Example 5 Manufacture of non-conductive particles> An aqueous dispersion of polymer particles (B-5) having a number average particle size of 950 nm was obtained in the same manner as in Example 1 except that 3.33% NaOH aqueous solution was used instead of 4% NaOH aqueous solution. It was.
• Example 6 Manufacture of non-conductive particles> An aqueous dispersion of polymer particles (B-6) having a number average particle diameter of 200 nm was obtained in the same manner as in Example 1 except that a 6.67% NaOH aqueous solution was used instead of the 4% NaOH aqueous solution. It was.
• a porous membrane-attached organic separator and a secondary battery were obtained in the same manner as in Example 1 except that the obtained slurry for a porous membrane was used and evaluated in the same manner. The results are shown in Table 1.
• a porous membrane-attached organic separator and a secondary battery were obtained in the same manner as in Example 1 except that the obtained slurry for a porous membrane was used and evaluated in the same manner. The results are shown in Table 1.
• Example 9 ⁇ Binder production> The amount of sodium dodecylbenzenesulfonate was changed from 0.8 part to 0.4 part, except that 64 parts of 2-ethylhexyl acrylate, 2 parts of methacrylic acid, and 34 parts of styrene were used as monomers used for polymerization.
• an aqueous dispersion of acrylic polymer binder (C-2) was obtained.
• the composition of the obtained acrylic polymer binder (C-2) was 64% 2-ethylhexyl acrylate unit, 2% methacrylic acid unit, and 34% styrene unit.
• Example 1 ⁇ Preparation of slurry for porous membrane, production of secondary battery> Then, in preparing the slurry for the porous membrane, Example 1 and Example 1 were used except that the acrylic polymer binder (C-2) obtained above was used instead of the acrylic polymer binder (C-1). Similarly, a porous membrane slurry was prepared, and the porous membrane-attached organic separator and the secondary battery were obtained in the same manner as in Example 1 except that the obtained porous membrane slurry was used. went. The results are shown in Table 1.
• Example 10 In the same manner as in Example 1, an aqueous dispersion of polymer particles (B-1) was obtained, and the obtained aqueous dispersion of polymer particles (B-1) was replaced with N-methyl 2-pyrrolidone. An N-methyl 2-pyrrolidone dispersion of polymer particles (B-1) was obtained.
• Example 11 Example except that acrylonitrile-methyl methacrylate copolymer (trade name “HB-69”, manufactured by Nippon Zeon Co., Ltd., 97% acrylonitrile unit, 3% methyl methacrylate unit) was used instead of hydrogenated nitrile rubber.
• acrylonitrile-methyl methacrylate copolymer trade name “HB-69”, manufactured by Nippon Zeon Co., Ltd., 97% acrylonitrile unit, 3% methyl methacrylate unit
• Example 12 In the same manner as in Example 1, an aqueous dispersion of acrylic polymer binder (C-1) was obtained, and the obtained aqueous dispersion of acrylic polymer binder (C-1) was replaced with N-methyl 2-pyrrolidone. Thus, an N-methyl 2-pyrrolidone dispersion of acrylic polymer binder (C-1) was obtained.
• a porous membrane was obtained in the same manner as in Example 10 except that the N-methyl 2-pyrrolidone dispersion of the acrylic polymer binder (C-1) obtained above was used.
• An organic separator with a porous membrane and a secondary battery were obtained and evaluated in the same manner as in Example 10 except that the slurry for a porous membrane was prepared and the obtained slurry for a porous membrane was used. The results are shown in Table 1.
• Example 13 A porous membrane slurry was prepared in the same manner as in Example 10 except that polyvinylidene fluoride (manufactured by Arkema) was used in place of the hydrogenated nitrile rubber, except that the obtained porous membrane slurry was used.
• polyvinylidene fluoride manufactured by Arkema
• an organic separator with a porous film and a secondary battery were obtained and evaluated in the same manner. The results are shown in Table 1.
• Example 14 Manufacture of electrode with porous membrane> A slurry for a porous membrane produced in the same manner as in Example 1 was applied to the negative electrode active material layer side surface of the negative electrode produced in the same manner as in Example 1 so that the thickness of the porous membrane after drying was 5 ⁇ m. A slurry layer was obtained. The slurry layer was formed so that the negative electrode active material layer was completely covered. And the formed slurry layer was dried at 110 degreeC for 10 minute (s), and the electrode with a porous film (negative electrode with a porous film) was obtained by making it into a porous film. In addition, the obtained electrode with a porous film had a layer structure of porous film / negative electrode active material layer / copper foil.
• Example 3 Manufacture of non-conductive particles>
• the number average particle size was the same as in Example 1 except that the blending amount of ethylene glycol dimethacrylate was changed from 83.3 parts to 50 parts and the blending amount of toluene was changed from 16.7 parts to 50 parts.
• the polymer particles (B-8) thus obtained were measured for BET specific surface area, particle size variation coefficient, and average circularity. The results are shown in Table 1.
• the number average particle diameter is 700 nm in the same manner as in Example 1 except that the aqueous dispersion of seed polymer particles (A-2) was used instead of the aqueous dispersion of seed polymer particles (A-1).
• An aqueous dispersion of polymer particles (B-9) was obtained.
• the polymer particles (B-9) thus obtained were measured for BET specific surface area, particle size variation coefficient, and average circularity. The results are shown in Table 1.
• the organic separator with a porous film formed by the organic separator and the porous film for a secondary battery of the present invention has a uniform film thickness and reliability in a high temperature environment (high temperature short circuit characteristics).
• the obtained secondary battery when used as a separator for a secondary battery, the obtained secondary battery was excellent in cycle characteristics and rate characteristics (Examples 1 to 13).
• the electrode with the porous film formed by the electrode and the porous film for the secondary battery of the present invention is also excellent in the uniformity of the film thickness and the reliability in the high temperature environment (high temperature short circuit resistance).
• the obtained secondary battery was excellent in cycle characteristics and rate characteristics (Example 14).
• the obtained organic separator with a porous membrane is inferior in reliability (high temperature short circuit resistance) in a high temperature environment, and when used as a separator for a secondary battery.
• the obtained secondary batteries were inferior in cycle characteristics and rate characteristics (Comparative Examples 2 to 4).

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