Composition for forming nonaqueous electrolyte secondary battery laminated separator and use thereof

Abstract

It is therefore possible to provide a composition for forming a nonaqueous electrolyte secondary battery laminated separator which composition allows a laminated separator to have a lower air permeability and allows a nonaqueous electrolyte secondary battery to have an improved rate characteristic.SOLUTION: A composition for forming a nonaqueous electrolytic solution secondary battery laminated separator according to the present disclosure includes a resin having an amide bond and an aromatic ring, and a ratio of an aromatic ring having a carboxy group to all aromatic rings in the resin is 0.2 to 2.0 mol%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery and its use. [Background technology]

[0002] Non-aqueous electrolyte secondary batteries, especially lithium ion secondary batteries, have a high energy density and are therefore widely used as batteries for personal computers, mobile phones, personal digital assistants, etc., and recently development has been progressing for use as batteries for automobiles.

[0003] As a separator, which is a component of the non-aqueous electrolyte secondary battery, for example, a laminate separator formed by laminating a porous layer such as a heat-resistant layer on one or both sides of a polyolefin porous film has been conventionally used. In recent years, with the trend toward higher battery capacities, there has been an increasing demand for laminate separators with high voltage resistance. As a laminate separator that meets this demand, a laminate separator having the following characteristics (a) and (b) has been developed, as described in Patent Document 1: (a) A porous layer is laminated on one or both sides of a polyolefin porous film; (b) The porous layer includes an aramid resin that is a block copolymer having a structure in which some aromatic rings are linked together by sulfonyl bonds, more specifically, a structure having a block with many sulfonyl groups and a block with few sulfonyl groups, and a filler. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-42995 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques have room for further improvement in terms of the air permeability of the laminate separator and the rate characteristics of the non-aqueous electrolyte secondary battery. One aspect of the present invention aims to provide a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery, which can reduce the air permeability of the laminate separator and improve the rate characteristics of the non-aqueous electrolyte secondary battery. [Means for solving the problem]

[0006] In order to solve the above problems, a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention includes a resin having an amide bond and an aromatic ring, and the proportion of aromatic rings having a carboxy group relative to all aromatic rings in the resin is 0.2 to 2.0 mol %. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to provide a composition for forming a laminate separator for a nonaqueous electrolyte secondary battery, which can reduce the air permeability of the laminate separator and improve the rate characteristics of the nonaqueous electrolyte secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below, but the present invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0009] 1. Composition for forming laminated separator for non-aqueous electrolyte secondary battery A composition for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention contains a resin having an amide bond and an aromatic ring, and the proportion of aromatic rings having a carboxy group relative to all aromatic rings in the resin is 0.2 to 2.0 mol %. Hereinafter, the laminate separator for a non-aqueous electrolyte secondary battery will also be simply referred to as a "laminated separator."

[0010] The resin in the composition has a higher content of carboxyl groups, which are polar functional groups, than the aramid resin described in Patent Document 1. Therefore, the resin in the composition has improved affinity with non-aqueous electrolytes, and as a result, the rate characteristics of non-aqueous electrolyte secondary batteries equipped with laminated separators containing the composition are improved.

[0011] Furthermore, the resin in the composition has a high carboxyl group content, which gives it a high affinity with solvents commonly used in coating solutions. Therefore, when the resin precipitates, components other than those containing carboxyl groups precipitate first to form a network structure, and then the components containing carboxyl groups precipitate near the network structure. This type of precipitation results in a layer with large pores, which reduces the air permeability of a laminated separator containing the composition.

[0012] <1-1. Resins containing amide bonds and aromatic rings> The composition includes a resin having an amide bond and an aromatic ring. The composition includes at least one type of the resin. That is, the resin may be one type of resin or a mixture of two or more types of resins.

[0013] The resin has a structure in which divalent groups are linked by chemical bonds, at least one of which is an amide bond. The resin can be prepared by a polymerization method in which the divalent groups are sequentially linked via the chemical bonds. Therefore, the resin obtained by the preparation method can contain a chain polymer consisting of a specific number or more of the divalent groups and a specific number or more of the chemical bonds.

[0014] Furthermore, in one embodiment of the present invention, the amide bond is a bond formed by condensation of an amino group (—NH) and a carboxylic acid halide (—C(═O)X) (X is a halogen atom such as F, Cl, Br, or I). Therefore, the resin having the amide bond may include a chain polymer whose terminal group is an amino group or a carboxylic acid halide. Note that the carboxylic acid halide is slowly hydrolyzed by water in the solvent to produce hydrogen halide and a carboxy group. Therefore, the resin having the amide bond may include a chain polymer whose at least one terminal is a carboxy group. A chain polymer whose terminal is a carboxy group has low reactivity with amino groups, so subsequent reactions tend to stop, resulting in a low-molecular-weight chain polymer. Specifically, the molecular weight of the low-molecular-weight chain polymer having a carboxy group is preferably 0.5 to 5.0 dL / g, more preferably 0.7 to 3.5 dL / g, and even more preferably 0.9 to 2.5 dL / g, when expressed in terms of intrinsic viscosity.

[0015] The resin may include a linear polymer having at least one terminal end of the polymer as a carboxyl group. A linear polymer having at least one terminal end of the polymer as a carboxyl group has higher solubility in organic solvents such as N-methyl-2-pyrrolidone (hereinafter referred to as NMP) and higher affinity for non-aqueous electrolytes than a linear polymer having both terminal ends of the polymer as amino groups. Furthermore, as described above, a linear polymer having a terminal carboxyl group tends to have a low molecular weight, and from this perspective, it also tends to have high solubility in organic solvents such as NMP.

[0016] In the resin, the proportion of amide bonds among the chemical bonds is preferably 45 to 85%, more preferably 55 to 75%, from the viewpoint of heat resistance of the layer containing the composition.

[0017] The divalent group is not particularly limited as long as it is a group containing an aromatic ring. In one embodiment of the present invention, the divalent group preferably contains a divalent aromatic group, and more preferably all of the divalent groups are divalent aromatic groups. The divalent group may be one type of group or two or more types of groups.

[0018] As used herein, the term "divalent aromatic group" refers to a divalent group containing an unsubstituted or substituted aromatic ring, and preferably refers to a divalent group consisting of an unsubstituted or substituted aromatic ring. The aromatic ring refers to a cyclic compound that satisfies Hückel's rule. Examples of aromatic rings include benzene, naphthalene, anthracene, azulene, pyrrole, pyridine, furan, and thiophene. In one embodiment of the present invention, the aromatic ring is composed only of carbon atoms and hydrogen atoms. In one embodiment of the present invention, the aromatic ring is a benzene ring or a condensed ring of two or more benzene rings (e.g., naphthalene, anthracene, etc.).

[0019] In one embodiment of the present invention, the substituent in the divalent group is not particularly limited. In one embodiment of the present invention, the substituent in the divalent group is preferably an electron-withdrawing substituent from the viewpoint of obtaining a layer that is resistant to deterioration even under high voltage conditions and has high voltage resistance. The electron-withdrawing substituent is not particularly limited, and examples thereof include a carboxy group, an alkoxycarbonyl group, a nitro group, and a halogen atom.

[0020] The chemical bond may be only an amide bond, or may include a bond other than an amide bond. The bond other than an amide bond is not particularly limited, and examples thereof include a sulfonyl bond, an alkenyl bond (e.g., a C1-C5 alkenyl bond), an ether bond, an ester bond, an imide bond, a ketone bond, and a sulfide bond. The bond other than an amide bond may be one type or two or more types.

[0021] In one embodiment of the present invention, the bonds other than the amide bonds preferably include bonds having stronger electron-withdrawing properties than the amide bonds, from the viewpoint of obtaining a layer having high-voltage resistance. Furthermore, from the viewpoint of further improving the high-voltage resistance of the layer, the proportion of the bonds having stronger electron-withdrawing properties than the amide bonds in the chemical bonds is more preferably 15 to 35%, and even more preferably 25 to 35%.

[0022] Examples of bonds having stronger electron-withdrawing properties than the amide bond include, among the chemical bonds listed above, sulfonyl bonds, ester bonds, and the like.

[0023] Specifically, the resin may be, for example, a polyamide, a polyamideimide, or a copolymer of a polyamide or a polyamideimide with a polymer having one or more bonds selected from a sulfonyl bond, an ether bond, and an ester bond. The copolymer may be a block copolymer or a random copolymer.

[0024] The polyamide is preferably an aromatic polyamide. Examples of the aromatic polyamide include fully aromatic polyamide (aramid resin) and semi-aromatic polyamide. The aromatic polyamide is preferably fully aromatic polyamide. Examples of the aromatic polyamide include para-aramid and meta-aramid.

[0025] The polyamideimide is preferably an aromatic polyamideimide. Examples of the aromatic polyamideimide include wholly aromatic polyamideimide and semi-aromatic polyamideimide. The aromatic polyamideimide is preferably wholly aromatic polyamideimide.

[0026] Examples of the polymer that constitutes the copolymer and has at least one bond selected from the group consisting of a sulfonyl bond, an ether bond, and an ester bond include polysulfone, polyether, and polyester.

[0027] In one embodiment, the resin is preferably an aramid resin. The aramid resin is not particularly limited, and examples thereof include a resin containing a block copolymer having a block A mainly composed of a unit represented by the following formula (1) and a block B mainly composed of a unit represented by the following formula (2). -(NH-Ar 1-NHCO-Ar 2 -CO)- (1) -(NH-Ar 3 -NHCO-Ar 4 -CO)- (2) (In formulas (1) and (2), Ar 1 , Ar 2 , Ar 3 and Ar 4 may be different for each unit, and Ar 1 , Ar 2 , Ar 3 and Ar 4 are each independently a divalent group having one or more aromatic rings, and all Ar 1 More than 50% of the compounds have a structure in which two aromatic rings are connected by a sulfonyl bond, and all Ar 3 Less than 50% of the compounds have a structure in which two aromatic rings are connected by a sulfonyl bond, and all Ar 1 and Ar 3 Of these, 10-70% have a structure in which two aromatic rings are linked by a sulfonyl bond. Of all the units contained in the block A in the block copolymer, the proportion of units of formula (1) is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The entire block A, excluding the terminals, is represented by units of formula (1). Of all the units contained in the block B, the proportion of units of formula (2) is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The entire block B, excluding the terminals, is represented by units of formula (2).

[0028] In the block A, at least a part of Ar 1 has a structure in which two aromatic rings are connected by a sulfonyl bond. 3 may have a structure in which two aromatic rings are connected by a sulfonyl bond. 1 and Ar 3 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 1 and Ar3 The lower limit of the proportion is 10% or more, preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. The upper limit of this proportion is 70% or less, preferably 65% ​​or less, and more preferably 60% or less.

[0029] In the block A, all Ar 1 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 1 The proportion of Ar in the block A is 50% or more, preferably 80% or more, and more preferably 90% or more. 1 However, it may have a structure in which two aromatic rings are linked by a sulfonyl bond.

[0030] In the block B, all Ar 3 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 3 The proportion of Ar in the block B is 50% or less, preferably 20% or less, and more preferably 10% or less. 3 may have a structure other than the structure in which two aromatic rings are connected by a sulfonyl bond.

[0031] Therefore, it can be said that the block A is a block with a relatively large amount of sulfonyl groups, and the block B is a block with a relatively small amount of sulfonyl groups. By using a block copolymer having these two types of blocks as the resin, it is possible to obtain a layer that can achieve both high voltage resistance and adhesiveness, and a laminate separator including this layer.

[0032] The structure in which the two aromatic rings are linked by a sulfonyl bond is not particularly limited, and examples thereof include 4,4'-diphenylsulfonyl, 3,4'-diphenylsulfonyl, and 3,3'-diphenylsulfonyl.

[0033] Examples of structures other than the structure in which the two aromatic rings are linked by a sulfonyl bond are not particularly limited, and include, for example, the structures shown below.

[0034] [ka]

[0035] At least a portion of the units of formula (1) contained in block A may be 4,4'-diphenylsulfonyl terephthalamide. In this case, the lower limit of the proportion of 4,4'-diphenylsulfonyl terephthalamide among the units of formula (1) contained in block A is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. 4,4'-diphenylsulfonyl terephthalamide is easy to handle, and the monomer is readily available.

[0036] At least a portion of the units of formula (2) contained in block B may be paraphenylene terephthalamide. In this case, the lower limit of the proportion of paraphenylene terephthalamide among the units of formula (2) contained in block B is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. Paraphenylene terephthalamide is easy to handle, and the monomer is readily available.

[0037] The block copolymer may have a structure composed of units other than those represented by formulas (1) and (2), such as a polyimide skeleton.

[0038] The number of blocks contained in the block copolymer is not particularly limited. The block copolymer may have, for example, a diblock structure such as block A-block B, or a triblock structure such as block A-block B-block A or block B-block A-block B. The block copolymer may also have a tetrablock structure such as block A-block B-block A-block B. Of the above structures, a triblock structure of block B-block A-block B is preferred as the structure of the block copolymer.

[0039] In one molecule of the block copolymer, the number of units of formula (1) contained in block A is preferably 10 to 1,000, more preferably 20 to 300. If the number of units of formula (1) is within the above-mentioned range, a sufficiently large number of sulfonyl groups will be contained in the molecule, and the high-voltage resistance of a layer obtained from the composition and a laminate separator including the layer will be enhanced. In one molecule of the block copolymer, the number of units of formula (2) contained in block B is preferably 10 to 500, more preferably 15 to 200. If the number of units of formula (2) is within the above-mentioned range, the adhesion of a layer obtained from the composition to other layers or electrodes will be enhanced.

[0040] Here, the number of units of the formula (1) and the formula (2), which are described as preferred values, is the number in the molecule corresponding to the mode of the molecular weight distribution of the block copolymer. The molecular weight distribution of the block copolymer can be experimentally determined, for example, by gel permeation chromatography.

[0041] The molecular weight of the block copolymer, expressed as an intrinsic viscosity, is preferably 0.5 to 5 dL / g, more preferably 0.8 to 2.5 dL / g. When the molecular weight is within the above range, good coatability when forming a layer from the composition and strength of the resulting layer and the laminate separator including the layer can be achieved at the same time.

[0042] When the composition contains the block copolymer, the content thereof is preferably 5 to 80 wt %, and more preferably 10 to 60 wt %, based on 100 wt % of the weight of the solid content contained in the composition. When the content is within the above range, the layer obtained from the composition and the laminate separator including the layer can be imparted with sufficient high-voltage resistance due to the electron-withdrawing property of the sulfonyl group of the block copolymer.

[0043] In the composition, the ratio of aromatic rings having a carboxy group to all aromatic rings in the resin is 0.2 to 2.0 mol %. This ratio of aromatic rings can be measured using H-NMR, specifically, by the method described in the Examples. The ratio of aromatic rings having a carboxy group correlates with the amount of the chain polymer having a carboxy group at least at one end.

[0044] The proportion of aromatic rings having a carboxy group is 0.2 mol% or more, preferably 0.3 mol% or more, and more preferably 0.4 mol% or more, from the viewpoints of air permeability and rate characteristics. Also, the proportion of aromatic rings having a carboxy group is 2.0 mol% or less, preferably 1.5 mol% or less, and more preferably 1.3 mol% or less, from the viewpoints of obtaining a composition having a certain molecular weight and capable of forming a layer.

[0045] As the resin, it is preferable to select an aramid resin containing the block copolymer, which has the following characteristics. -Contains many polymers with a structure that has a carboxyl group (C(=O)-OH) at the terminal structure.

[0046] Hereinafter, a homopolymer having the same structure as the block A and having low reactivity with monomers and other polymers at at least one end is referred to as a "homopolymer A." Furthermore, an aramid resin containing the block copolymer and having the above characteristics is referred to as a "modified aramid resin."

[0047] The homopolymer A is a by-product that may be generated during the preparation of the block copolymer. Specifically, the homopolymer A has a structure in which the terminal group is a carboxy group. The homopolymer A corresponds to the low-molecular-weight chain polymer described above, in which at least one terminal is a carboxy group.

[0048] Similarly, during the preparation of the block copolymer, a block copolymer having a carboxyl group at its terminal may also be produced. A block copolymer having low reactivity with monomers and other polymers at at least one terminal is referred to as "block copolymer A." In addition, as another by-product, a homopolymer having the same structure as block B and having low reactivity with monomers and other polymers at at least one terminal may also be produced. Hereinafter, a homopolymer having the same structure as block B and having low reactivity with monomers and other polymers at its terminal is referred to as "homopolymer B."

[0049] Since at least one end of the homopolymers A and B and the block copolymer A is a carboxyl group, the modified aramid resin contains many carboxyl groups, which are highly polar functional groups, and has improved affinity with non-aqueous electrolytes. Therefore, a laminate separator including a layer containing the modified aramid resin can improve the rate characteristics of a non-aqueous electrolyte secondary battery including the laminate separator.

[0050] Furthermore, homopolymers A, B, and block copolymer A have a higher affinity with solvents commonly used in the coating liquid, such as NMP, than other polymers contained in the modified aramid resin that do not have terminal carboxy groups. Therefore, homopolymers A, B, and block copolymer A have high solubility in the solvent. Therefore, when a layer is formed from the composition, the other polymers that do not have carboxy groups first precipitate to form a network structure, and then homopolymers A, B, and block copolymer A precipitate near the network structure. This type of precipitation results in a layer with large pores, resulting in reduced air permeability for the layer and for the laminate separator comprising the layer. Therefore, a laminate separator comprising a layer containing the modified aramid resin has a low air permeability value and is also excellent in terms of air permeability.

[0051] The composition may contain a filler. When the composition contains a filler, the content of the filler in the composition is preferably 20 to 90% by weight, and more preferably 30 to 80% by weight, where the total amount of the resin and the filler is 100% by weight. When the content of the filler is within the above range, the layer obtained from the composition and the laminate separator including the layer can have sufficient ion permeability.

[0052] The filler types include organic fillers, inorganic fillers, and mixtures thereof.

[0053] Examples of the organic filler include styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, and the like, alone or in copolymers of two or more thereof; fluororesins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polyvinylidene fluoride; melamine resin; urea resin; polyolefin; polymethacrylate; and the like. The organic fillers may be used alone or in combination of two or more. Among these organic fillers, polytetrafluoroethylene powder is preferred in terms of chemical stability. Furthermore, polyolefins may be used as the organic filler to improve the shutdown property of the laminate separator. When polyolefins are used as the organic filler, shutdown property can be imparted to the layer obtained from the composition.

[0054] Examples of the inorganic filler include inorganic materials such as metal oxides, metal nitrides, metal carbides, metal hydroxides, carbonates, and sulfates. Specific examples include powders of aluminum oxide (e.g., alumina), boehmite, silica, titania, magnesia, barium titanate, barium sulfate, magnesium hydroxide, aluminum hydroxide, and calcium carbonate; as well as minerals such as mica, zeolite, kaolin, and talc. The inorganic fillers may be used alone or in combination. Among these inorganic fillers, aluminum oxide is preferred in terms of chemical stability.

[0055] The shape of the filler may be substantially spherical, plate-like, columnar, needle-like, whisker-like, fibrous, etc., and any of these particles may be used. Substantially spherical particles are preferred because they are more likely to form uniform pores.

[0056] The average particle size of the filler is preferably 0.01 to 1 μm, more preferably 0.01 to 0.8 μm. Fillers with an average particle size of 0.01 μm or more tend to increase the pore size in the layer obtained from the composition, thereby preventing a decrease in ion permeability even when the laminate separator is compressed in a battery. Furthermore, irregularities are more likely to form on the surface of the layer obtained from the composition, improving the slipperiness of the laminate separator. On the other hand, when the average particle size of the filler is 1 μm or less, the heat resistance of the laminate separator can be improved and the laminate separator can be made thinner. To achieve both of these properties, fillers with different average particle sizes may be used in combination, or a filler with a wide particle size distribution may be used. In this specification, the "average particle size of the filler" refers to the volume-based average particle size (D50) of the filler. D50 refers to the particle size at which the cumulative distribution on a volume basis is 50%. D50 can be measured, for example, using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, trade names: SALD2200, SALD2300, etc.).

[0057] The composition may contain other components in addition to the resin having an amide bond and an aromatic ring and the filler, provided that the object of the present invention is not impaired. Examples of the other components include resins other than the resin having an amide bond and an aromatic ring, and additives commonly used in separators for nonaqueous electrolyte secondary batteries. The other components may be one type or a mixture of two or more types.

[0058] Examples of resins other than the resin having an amide bond and an aromatic ring include polyolefins; (meth)acrylate resins; fluorine-containing resins; polyester resins; rubbers; resins with a melting point or glass transition temperature of 180°C or higher; water-soluble polymers; polycarbonate, polyacetal, polyether ether ketone, polybenzimidazole, polyurethane, and melamine resin. For example, when a polyamide resin having excellent heat resistance is mixed with a (meth)acrylate resin and / or a fluorine-containing resin having adhesive properties, a layer having both heat resistance and adhesive properties can be obtained. In this case, the form of the (meth)acrylate resin and / or the fluorine-containing resin is not particularly limited, and may be in the form of particles, may be present in a mixture with the polyamide resin, or may be segregated on the surface of the layer obtained from the composition.

[0059] The polyolefin is not particularly limited, and examples thereof include polyethylene, polypropylene, polybutene, and ethylene-propylene copolymer.

[0060] The (meth)acrylate resin is not particularly limited, and examples thereof include methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

[0061] The fluorine-containing resin is not particularly limited, and examples thereof include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, and ethylene-tetrafluoroethylene copolymer, as well as fluorine-containing rubbers having a glass transition temperature of 23°C or lower among the fluorine-containing resins.

[0062] The polyester resin is not particularly limited, and examples thereof include aromatic polyesters and liquid crystal polyesters. The aromatic polyester is not particularly limited, and examples thereof include polyarylates.

[0063] Examples of the rubbers include styrene-butadiene copolymers and hydrogenated products thereof, methacrylic acid ester copolymers, acrylonitrile-acrylic acid ester copolymers, styrene-acrylic acid ester copolymers, ethylene propylene rubber, and polyvinyl acetate.

[0064] Examples of the resin having a melting point or glass transition temperature of 180° C. or higher include polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyamideimide, polyetheramide, and polyetheretherketone.

[0065] Examples of the water-soluble polymer include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, and polymethacrylic acid.

[0066] Examples of the additives include flame retardants, antioxidants, surfactants, and waxes. If the layer obtained from the composition is prone to static electricity, adding an antistatic agent can suppress static electricity in the layer. Furthermore, adding a flame retardant and / or a crosslinking agent can further improve the safety and heat resistance of the separator.

[0067] <1-2. Method for producing the composition> The composition can be produced using a resin having an amide bond and an aromatic ring, and an example of such a resin is the modified aramid resin described above. The method for controlling the ratio of aromatic rings having a carboxy group to all aromatic rings in the resin is not particularly limited, and examples thereof include a method of satisfying the production conditions shown in (i) and (ii) below.

[0068] A method for preparing the modified aramid resin will be described below. First, as a method for preparing the aramid resin containing the block copolymer, for example, the following methods 1 and 2 can be mentioned. By this method, an aramid resin containing a block copolymer having a diblock structure of block A-block B can be prepared. In addition, an aramid resin containing a block copolymer having other block structures can also be prepared by applying the following procedure and production conditions. 1.NH2-Ar 1 -NH2 and X-(O=)C-Ar 2 A dicarboxylic acid halide represented by -C(=O)-X (X is a halogen atom such as F, Cl, Br, or I) is used as a monomer and polymerized according to a known aromatic polyamide polymerization method, thereby synthesizing a block A having a unit of formula (1). 2. After the synthesis of Block A is completed, NH2-Ar 3 -NH2 and X-(O=)C-Ar 4A dicarboxylic acid halide represented by -C(=O)-X (X is a halogen atom such as F, Cl, Br, or I) is used as a monomer and polymerized according to a known aromatic polyamide polymerization method. This synthesizes block B having the unit of formula (2) linked to block A.

[0069] A modified aramid resin that can be suitably used for producing the composition can be prepared by a method that satisfies the production conditions shown in the following (i) and (ii) in the method according to the procedures shown in 1. and 2. (i) In the synthesis of block A described in 1 above, the water content of the solvent used is set to be higher than that in conventional methods for producing the block copolymer, for example, preferably 400 ppm or more, more preferably 450 ppm or more. (ii) In the synthesis of block A shown in 1 above, the charge ratio, which is the molar ratio of the diamine to the dicarboxylic acid halide, is set to a range close to 1.00, for example, preferably 0.99 to 1.01, more preferably 0.995 to 1.005.

[0070] Here, the aramid resin containing a block copolymer produced by the methods shown in 1. and 2. above may contain homopolymers A and B and block copolymer A as by-products.

[0071] When the condition (i) is satisfied, in 1. and 2., the polymer end group C(=O)-X (X is a halogen atom such as F, Cl, Br, or I) reacts with water molecules (HO), and the end group is easily converted into a carboxy group: C(=O)-OH. Here, the carboxy group corresponds to a group that has low reactivity with monomers and other polymers. Therefore, the proportion of polymers containing carboxy groups contained in the modified aramid resin increases.

[0072] Therefore, when the above condition (i) is satisfied, a modified aramid resin having a high content of polymers having carboxy groups can be suitably prepared.

[0073] On the other hand, when the condition (i) is satisfied, the C(═O)—X group, which is the reaction site, is likely to become a carboxy group that has low reactivity with monomers and other polymers during the polymerization reaction that produces block A. Therefore, when the condition (i) is satisfied, the degree of polymerization of block A decreases, and the weight-average molecular weight of the resulting modified aramid resin is likely to decrease. Here, if the weight-average molecular weight of the modified aramid resin is low, the modified aramid resin has high solubility in solvents and is difficult to precipitate in the method for producing the laminate separator, so there is a risk that a layer will not be formed from the composition, making it impossible to produce the laminate separator.

[0074] However, when the charge ratio is close to 1.00, the number of monomers that become the terminal groups of block A decreases, and the degree of polymerization of block A increases, resulting in a higher weight-average molecular weight of the resulting modified aramid resin. Thus, by satisfying condition (ii), even when condition (i) is satisfied, the weight-average molecular weight of the resulting modified aramid resin can be increased to an extent that allows a layer to be suitably formed from the composition and allows the laminate separator to be suitably produced.

[0075] 2. Layers for forming laminated separators for non-aqueous electrolyte secondary batteries The layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention contains the above-described composition. The layer is, for example, a porous layer.

[0076] The air permeability of the layer is preferably 400 s / 100 mL or less, and more preferably 200 s / 100 mL or less. If the air permeability of the layer is within the above range, it can be said that the laminated separator has sufficient ion permeability. In this specification, the air permeability represents a value measured using an Oken air permeability tester in accordance with JIS P8117.

[0077] For example, when the laminated separator consists only of a polyolefin porous film and the layer, the air permeability of the layer is calculated as YX, where X is the air permeability of the polyolefin porous film and Y is the air permeability of the laminated separator.

[0078] The weight per unit area of ​​the layer, i.e., the basis weight, is 0.6 to 2.5 g / m from the viewpoint of controlling the air permeability within a suitable range. 2 It is preferable that the density is 0.8 to 2.0 g / m 2 It is more preferable that:

[0079] The upper limit of the thickness of the layer is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less, and the lower limit of the thickness of the layer is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.6 μm or more.

[0080] [3. Laminated separator for non-aqueous electrolyte secondary batteries] A laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention comprises a polyolefin porous film and a layer for forming the laminate separator for a non-aqueous electrolyte secondary battery laminated on one or both sides of the polyolefin porous film. That is, the laminate separator includes a polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery laminated on one or both sides of the polyolefin porous film. Hereinafter, the polyolefin porous film will also be simply referred to as a "porous film." The layer for forming the laminate separator for a non-aqueous electrolyte secondary battery is also a layer containing the above-mentioned composition.

[0081] The air permeability of the laminate separator is preferably 500 s / 100 mL or less, and more preferably 300 s / 100 mL or less. If the air permeability of the laminate separator is within the above range, it can be said that the laminate separator has sufficient ion permeability.

[0082] The layer containing the composition may be provided on one side of the porous film or on both sides of the porous film, and the layer containing the composition and the layer containing the composition provided on both sides of the porous film may have the same or different film thickness, basis weight, and porosity.

[0083] <3-1. Porous film> The porous film has many interconnected pores within it, allowing gases and liquids to pass from one side to the other. The porous film can serve as a substrate for a laminated separator. The porous film can melt when the battery generates heat, rendering the laminated separator porous, thereby imparting a shutdown function to the laminated separator.

[0084] Here, the term "polyolefin porous film" refers to a porous film mainly composed of a polyolefin resin. Furthermore, "mainly composed of a polyolefin resin" means that the proportion of polyolefin resin in the porous film is 50% by volume or more, preferably 90% by volume or more, and more preferably 95% by volume or more of the total material constituting the porous film.

[0085] The polyolefin resin, which is the main component of the porous film, is not particularly limited, and examples thereof include homopolymers and copolymers obtained by polymerizing monomers such as thermoplastic resins, such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and / or 1-hexene. Homopolymers include polyethylene, polypropylene, and polybutene, while copolymers include ethylene-propylene copolymers. The porous film may be a layer containing one of these polyolefin resins alone, or a layer containing two or more of these polyolefin resins. Among these, polyethylene is more preferred because it can prevent (shut down) excessive current flow at lower temperatures, and high-molecular-weight polyethylene composed primarily of ethylene is particularly preferred. The polyolefin porous film may contain components other than polyolefins as long as their functionality is not impaired.

[0086] Examples of polyethylene include low-density polyethylene, high-density polyethylene, linear polyethylene (ethylene-α-olefin copolymer), and ultra-high molecular weight polyethylene. Among these, ultra-high molecular weight polyethylene is more preferred, and the weight-average molecular weight is 5×10 5 ~15×10 6 It is particularly preferable that the polyolefin resin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, since this improves the strength of the porous film and the laminate separator.

[0087] The porous film may have a multilayer structure consisting of two or more layers. An example of a porous film with a multilayer structure is one in which a layer mainly composed of polyethylene and a layer mainly composed of polypropylene are laminated together. The number of layers is not particularly limited, and the film may be two layers composed of polyethylene and polypropylene, or three layers composed of a combination of polyethylene and polypropylene. By using a multilayer structure of polyethylene and polypropylene, it is possible to achieve both shutdown properties and heat resistance.

[0088] The porous film may have a crosslinked structure. The crosslinked structure can be introduced, for example, by using a silane-modified polyolefin. A porous film having a crosslinked structure has excellent heat resistance, and therefore, by combining it with a layer containing the composition, the heat resistance of the laminated separator can be further improved. The crosslinked structure may be formed between the porous film and the layer containing the composition.

[0089] The thickness of the porous film is preferably 3 to 20 μm, more preferably 4 to 15 μm, and even more preferably 4.5 to 15 μm. If the thickness is 3 μm or more, the strength of the laminated separator can be ensured. Furthermore, if the thickness is 3 μm or more, the required functions (shutdown function, etc.) can be sufficiently obtained. If the thickness is 20 μm or less, a thin laminated separator can be obtained.

[0090] The pore size of the porous film is preferably 0.1 μm or less, and more preferably 0.06 μm or less, which allows for sufficient ion permeability and better prevents particles constituting the electrode from entering.

[0091] The weight per unit area of ​​the porous film, i.e., the weight per unit area, is usually 2 to 20 g / m2 so as to increase the weight energy density and volume energy density of the battery. 2 It is preferable that the density is 2.5 to 12 g / m 2 It is more preferable that:

[0092] The air permeability of the porous film is preferably 30 to 500 s / 100 mL, and more preferably 50 to 300 s / 100 mL, which allows the laminated separator to have sufficient ion permeability.

[0093] The porosity of the porous film is preferably 20 to 80% by volume, more preferably 30 to 75% by volume, which increases the amount of electrolyte retained and reliably prevents excessive current from flowing even at low temperatures.

[0094] The method for producing a porous film is not particularly limited and may be a known method, such as a method described in Japanese Patent No. 5476844 in which a filler is added to a thermoplastic resin, a film is formed, and then the filler is removed.

[0095] Specifically, for example, when the porous film is formed from a polyolefin resin containing ultra-high molecular weight polyethylene and a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, it is preferably produced by a method including the following steps (1) to (4) from the viewpoint of production costs: (1) A step of kneading 100 parts by weight of ultra-high molecular weight polyethylene, 5 to 200 parts by weight of a low-molecular weight polyolefin having a weight-average molecular weight of 10,000 or less, and 100 to 400 parts by weight of an inorganic filler such as calcium carbonate to obtain a polyolefin-based resin composition; (2) forming a sheet from the polyolefin resin composition; (3) a step of removing the inorganic filler from the sheet obtained in step (2); (4) A step of stretching the sheet obtained in step (3). In addition, the methods described in the above-mentioned patent documents may also be used.

[0096] <3-2. Another functional layer> The laminate separator may include a functional layer different from the porous film and the layer containing the composition, as needed, without impairing the objectives of the present invention. Examples of such functional layers include an adhesive layer, a heat-resistant porous layer different from the layer containing the composition, a slip layer intended to improve the slippage of the separator, a layer containing organic particles such as polyolefins intended to provide shutdown properties, an antistatic layer, a protective layer, and other known porous layers. For example, the laminate separator may include, in addition to the porous film and the layer containing the composition, a functional layer different from the layer containing the composition, as needed, without impairing the objectives of the present invention. A heat-resistant porous layer different from the layer containing the composition means that the type of resin and filler, the amount of filler, etc., differ from those of the layer containing the composition. When the functional layer is a heat-resistant porous layer different from the layer containing the composition, the resin, filler, and filler amount exemplified for the composition can be applied to the functional layer. The slip layer may be a layer containing an antiblocking agent or a layer containing a filler, and the slippage of the separator can be improved by providing surface irregularities.

[0097] The other functional layer may be provided on one or both sides of the laminated separator. When the laminated separator has layers containing the composition on both sides of a porous film, the other functional layer may be provided on the layers containing the composition on both sides, or on the layer containing the composition on one side. When the laminated separator has a layer containing the composition on only one side of a porous film, the other functional layer may be provided on the layer containing the composition, or on the side of the porous film that does not have the layer containing the composition. The other functional layer may be provided in the outermost layer of the laminated separator.

[0098] For example, the laminated separator further includes an adhesive layer in addition to the porous film and the layer containing the composition. In this specification, the adhesive layer refers to a layer having adhesive properties. The adhesive layer may be provided on the surface of the laminated separator that contacts the electrode. Examples of components contained in the adhesive layer that contribute to adhesiveness include acrylic resins and PVDF-based resins. Examples of acrylic resins that can be used include those described in paragraphs

[0072] to

[0088] of JP 2024-006988 A. Examples of PVDF-based resins that can be used include those described in paragraphs

[0017] to

[0022] of JP 2017-168419 A. The acrylic resins and PVDF-based resins may be used alone or in combination. The adhesive layer may further include a filler in addition to the components that contribute to adhesiveness. Examples of fillers that can be used include those similar to the fillers added to the composition. The state of the adhesive layer is not particularly limited, and the component that contributes to adhesiveness may be present in particulate form or as a homogeneous coating layer. The adhesive layer may also be present in a dotted or striped form by pattern coating. By providing the adhesive layer, the laminated separator is fixed to the electrode via the adhesive layer, thereby improving the handleability and heat resistance of the electrode laminate. Furthermore, by providing the adhesive layer in a particulate, dotted, or striped form, a decrease in the ion permeability of the laminated separator can be suppressed.

[0099] <3-3. Manufacturing method of layers and manufacturing method of laminated separator> For example, the laminated separator can be produced by forming a layer on one or both sides of the porous film using a coating liquid in which the components constituting the composition are dissolved or dispersed in a solvent. Examples of methods for forming the coating liquid include mechanical stirring, ultrasonic dispersion, high-pressure dispersion, and media dispersion. Examples of solvents that can be used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide. The solvent can also be considered a dispersion medium that disperses the components constituting the composition.

[0100] The method for producing the laminate separator includes, for example, preparing the coating liquid, applying the coating liquid to a porous film, and drying the coating liquid to form a layer containing the composition on the porous film. In the method for producing the layer, the object to which the coating liquid is applied is not limited to a porous film, and other films, positive electrodes, negative electrodes, etc. may also be used.

[0101] The coating liquid can be applied to the porous film by any known coating method such as a knife, blade, bar, gravure, or die.

[0102] The solvent is generally removed by drying. Examples of drying methods include natural drying, air drying, heat drying, and reduced pressure drying, but any method may be used as long as it can sufficiently remove the solvent. Alternatively, the solvent contained in the paint may be replaced with another solvent before drying. Specific examples of methods for replacing the solvent with another solvent before removal include replacing the solvent with a low-boiling point poor solvent such as water, alcohol, or acetone, precipitating the solvent, and then drying the resulting mixture.

[0103] 4. Non-aqueous electrolyte secondary battery components and non-aqueous electrolyte secondary batteries A nonaqueous electrolyte secondary battery member according to one embodiment of the present invention includes a positive electrode, the above-described laminated separator, and a negative electrode arranged in this order. A nonaqueous electrolyte secondary battery according to one embodiment of the present invention also includes the above-described laminated separator.

[0104] The nonaqueous electrolyte secondary battery typically has a structure in which a negative electrode and a positive electrode face each other with the laminate separator interposed therebetween. In the nonaqueous electrolyte secondary battery, a battery element in which the structure is impregnated with an electrolyte is sealed in an exterior material. For example, the nonaqueous electrolyte secondary battery is a lithium ion secondary battery that generates electromotive force by doping and undoping lithium ions.

[0105] <Positive electrode> The positive electrode may be, for example, a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a current collector. The active material layer may further contain a conductive agent.

[0106] The positive electrode active material may be, for example, a material that can be doped and dedoped with lithium ions.

[0107] Examples of such materials include lithium composite oxides containing at least one transition metal, such as V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. Examples of lithium composite oxides include lithium composite oxides having a layered structure, lithium composite oxides having a spinel structure, and solid-solution lithium-containing transition metal oxides composed of lithium composite oxides having both a layered structure and a spinel structure. Other examples include lithium cobalt composite oxides and lithium nickel composite oxides. Furthermore, examples of these lithium composite oxides in which a portion of the transition metal atoms that constitute the main component of the lithium composite oxides has been substituted with other elements, such as Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg, Ca, Ga, Zr, Si, Nb, Mo, Sn, and W, are also included.

[0108] Examples of the lithium composite oxide in which a portion of the transition metal atoms that constitute the main component of the lithium composite oxide are substituted with other elements include a lithium cobalt composite oxide having a layered structure represented by the following formula (3), a lithium nickel composite oxide represented by the following formula (4), a lithium manganese composite oxide having a spinel structure represented by the following formula (5), and a solid solution lithium-containing transition metal oxide represented by the following formula (6).

[0109] Li x (Co 1-a M 1 a ) 1-x ]O2...Equation (3) (In formula (3), M 1is at least one metal selected from the group consisting of Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, and satisfies -0.1 ≦ x ≦ 0.30, 0 ≦ a ≦ 0.5.) Li[Li y (Ni 1-b M 2 b ) 1-y O2···Formula (4) (In formula (4), M 2 is at least one metal selected from the group consisting of Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, and satisfies -0.1 ≦ y ≦ 0.30, 0 ≦ b ≦ 0.5.) Li z Mn 2-c M 3 c O4···Formula (5) (In formula (5), M 3 is at least one metal selected from the group consisting of Na, K, B, F, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, and satisfies 0.9 ≦ z, 0 ≦ c ≦ 1.5.) Li 1+w M 4 d M 5 e O2···Formula (6) (In formula (6), M 4 and M 5 are at least one metal selected from the group consisting of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg, and Ca, and satisfy 0 < w ≦ 1 / 3, 0 ≦ d ≦ 2 / 3, 0 ≦ e ≦ 2 / 3, w + d + e = 1.) Specific examples of the lithium composite oxide represented by the above formulas (3) to (6) include LiCoO2, LiNiO2, LiMnO2, LiNi 0.8 Co 0.2 O2, LiNi (式(4)中、M 2 はNa、K、B、F、Al、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Mg、Ga、Zr、Si、Nb、Mo、Sn及びWからなる群から選ばれる少なくとも1種の金属であり、-0.1≦y≦0.30、0≦b≦0.5、を満たす。) Li z Mn 2-c M 3 c O4···式(5) (式(5)中、M 3 はNa、K、B、F、Al0.8 Co 0.15 Al 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, LiMn2O4, LiMn 1.5 Ni 0.5 O4, LiMn 1.5 Fe 0.5 O4, LiCoMnO4, Li 1.21 Ni 0.20 Mn 0.59 O2, Li 1.22 Ni 0.20 Mn 0.58 O2, Li 1.22 Ni 0.15 Co 0.10 Mn 0.53 O2, Li 1.07 Ni 0.35 Co 0.08 Mn 0.50 O2, Li 1.07 Ni 0.36 Co 0.08 Mn 0.49 Examples include O2.

[0110] In addition, lithium composite oxides other than those represented by formulas (3) to (6) can also be preferably used as the positive electrode active material. Examples of such lithium composite oxides include LiNiVO4, LiV3O6, Li 1.2 Fe 0.4 Mn 0.4 Examples include O2.

[0111] Materials other than lithium composite oxides that can be preferably used as the positive electrode active material include, for example, phosphates having an olivine structure, such as those represented by the following formula (7):

[0112] Li v (M 6 f M 7g M 8 h M 9 i ) j PO4...Equation (7) (In formula (7), M 6 is Mn, Co, or Ni, and M 7 is Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, or Mo, and M 8 is a transition metal or main group element, optionally excluding elements of groups VIA and VIIA, and M 9 is a transition metal or a main group element, optionally excluding elements of Groups VIA and VIIA, and satisfies 1.2 ≥ a ≥ 0.9, 1 ≥ b ≥ 0.6, 0.4 ≥ c ≥ 0, 0.2 ≥ d ≥ 0, 0.2 ≥ e ≥ 0, 1.2 ≥ f ≥ 0.9. The positive electrode active material preferably has a coating layer on the surface of the lithium metal composite oxide particles constituting the positive electrode active material. Examples of materials constituting the coating layer include metal composite oxides, metal salts, boron-containing compounds, nitrogen-containing compounds, silicon-containing compounds, and sulfur-containing compounds, and among these, metal composite oxides are preferably used.

[0113] The metal composite oxide is preferably an oxide having lithium ion conductivity. Examples of such metal composite oxides include metal composite oxides of Li and at least one element selected from the group consisting of Nb, Ge, Si, P, Al, W, Ta, Ti, S, Zr, Zn, V, and B. When the positive electrode active material has a coating layer, the coating layer suppresses side reactions at the interface between the positive electrode active material and the electrolyte under high voltage, thereby achieving a longer life for the resulting secondary battery. Furthermore, the formation of a high-resistance layer at the interface between the positive electrode active material and the electrolyte is suppressed, thereby achieving a higher output for the resulting secondary battery.

[0114] Examples of the conductive agent include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fiber, and baked organic polymer compounds.

[0115] Examples of the binder include polyvinylidene fluoride, vinylidene fluoride copolymers, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-tetrafluoroethylene copolymers, vinylidene fluoride-trifluoroethylene copolymers, vinylidene fluoride-trichloroethylene copolymers, vinylidene fluoride-vinyl fluoride copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, thermoplastic resins such as thermoplastic polyimide, polyethylene, and polypropylene, acrylic resins, and styrene-butadiene rubber. The binder also functions as a thickener.

[0116] Examples of the positive electrode current collector include conductors such as Al, Ni, stainless steel, etc. Among these, Al is more preferred because it can be easily processed into a thin film and is inexpensive.

[0117] Examples of methods for producing a sheet-like positive electrode include a method in which a positive electrode active material, a conductive agent, and a binder that constitute a positive electrode mixture are pressure-molded on a positive electrode current collector; and a method in which a positive electrode active material, a conductive agent, and a binder are made into a paste using an appropriate organic solvent to obtain a positive electrode mixture, and then the positive electrode mixture is applied to a positive electrode current collector and dried to obtain a sheet-like positive electrode mixture, which is then pressed to adhere to the positive electrode current collector.

[0118] <Negative electrode> The negative electrode may be, for example, a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a current collector. The active material layer may further contain a conductive agent.

[0119] Examples of the negative electrode active material include carbon materials, chalcogen compounds (oxides, sulfides, etc.), nitrides, metals, and alloys that can be doped and dedoped with lithium ions at a lower potential than the positive electrode.

[0120] Examples of carbon materials that can be used as the negative electrode active material include graphite such as natural graphite and artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fiber, and fired organic polymer compounds.

[0121] Examples of oxides that can be used as the negative electrode active material include oxides represented by the formula SiO x (where x is a positive real number); oxides of silicon such as TiO2 and TiO with the formula TiO x (where x is a positive real number); oxides of titanium represented by the formula V such as V2O5 and VO2 x O y (where x and y are positive real numbers); oxides of vanadium such as Fe3O4, Fe2O3, and FeO, with the formula Fe x O y (where x and y are positive real numbers); oxides of iron, such as SnO2 and SnO, with the formula SnO x (where x is a positive real number); tin oxides such as WO3 and WO2, with the general formula WO x (where x is a positive real number) is the oxide of tungsten; Li4Ti5O 12 and composite metal oxides containing lithium, such as LiVO2, and titanium or vanadium;

[0122] Examples of sulfides that can be used as the negative electrode active material include those represented by the formula Ti, such as Ti2S3, TiS2, and TiS. x S y (where x and y are positive real numbers); titanium sulfides such as V3S4, VS2, and VS, with the formula VS x (where x is a positive real number); vanadium sulfides such as Fe3S4, FeS2, and FeS, with the formula Fe x S y (where x and y are positive real numbers); iron sulfides such as Mo2S3 and MoS2 with the formula Mo x S y (where x and y are positive real numbers) Molybdenum sulfides such as SnS2 and SnS with the formula SnS xSulfide of tin represented by (where x is a positive real number); sulfide of tungsten such as WS2, formula WS x Sulfide of tungsten represented by (where x is a positive real number); sulfide of antimony such as Sb2S3, formula Sb x S y Sulfide of antimony represented by (where x and y are positive real numbers); formula Se x S y Sulfide of selenium represented by (where x and y are positive real numbers); can be mentioned.

[0123] As nitrides that can be used as the negative electrode active material, for example, Li3N, Li 3-x A x Lithium-containing nitrides such as N(where A is either one or both of Ni and Co, and 0 < x < 3).

[0124] These carbon materials, oxides, sulfides, and nitrides may be used alone or in combination of two or more. Also, these carbon materials, oxides, sulfides, and nitrides may be either crystalline or amorphous. These carbon materials, oxides, sulfides, and nitrides are mainly supported on the negative electrode current collector and used as an electrode.

[0125] Also, as metals that can be used as the negative electrode active material, lithium metal, silicon metal, tin metal, etc. can be mentioned.

[0126] Also, composite materials containing Si or Sn as the first constituent element and in addition the second and third constituent elements can be mentioned. The second constituent element is, for example, at least one of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, and zirconium. The third constituent element is, for example, at least one of boron, carbon, aluminum, and phosphorus.

[0127] Particularly, since high battery capacity and excellent battery characteristics can be obtained, as the metal material, silicon or tin alone (may contain trace impurities), SiO v(0 <v≦2)、SnO w (0≦w≦2), Si—Co—C composite material, Si—Ni—C composite material, Sn—Co—C composite material, and Sn—Ni—C composite material are preferred.

[0128] Examples of the negative electrode current collector include Cu, Ni, stainless steel, etc. Among them, Cu is more preferable, particularly in lithium ion secondary batteries, because it is difficult to form an alloy with lithium and it can be easily processed into a thin film.

[0129] Examples of methods for producing a sheet-like negative electrode include a method of press-molding a negative electrode active material that will become a negative electrode mixture onto a negative electrode current collector, a method of forming a negative electrode active material into a paste using an appropriate organic solvent to obtain a negative electrode mixture, applying the negative electrode mixture to a negative electrode current collector, drying the mixture, and then pressing the resulting sheet-like negative electrode mixture to adhere it to the negative electrode current collector. The paste preferably contains the conductive agent and the binder.

[0130] <Nonaqueous electrolyte> The non-aqueous electrolyte may be, for example, a non-aqueous electrolyte prepared by dissolving a lithium salt in an organic solvent. Examples of lithium salts include LiClO4, LiPF6, LiAsF6, LiSbF6, LiBF4, LiSO3F, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(COCF3), Li(C4F9SO3), LiC(SO2CF3)3, and Li2B 10 Cl 10 , LiBOB (here, BOB stands for bis(oxalato)borate), lithium salts of lower aliphatic carboxylic acids, LiAlCl4, etc. These may be used alone or as a mixture of two or more. Among them, it is preferable to use a lithium salt containing at least one selected from the group consisting of fluorine-containing LiPF6, LiAsF6, LiSbF6, LiBF4, LiSO3F, LiCF3SO3, LiN(SO2CF3)2, and LiC(SO2CF3)3.

[0131] Examples of organic solvents include carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1,3-dioxolan-2-one, and 1,2-di(methoxycarbonyloxy)ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran. esters such as methyl formate, methyl acetate, and γ-butyrolactone; nitriles such as acetonitrile and butyronitrile; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 1,3-propane sultone; or organic solvents such as these with a fluoro group introduced therein (organic solvents in which one or more hydrogen atoms have been replaced with fluorine atoms).

[0132] It is preferable to mix two or more of the organic solvents and use them as a mixed solvent. Among them, a mixed solvent containing a carbonate is preferred, and a mixed solvent of a cyclic carbonate and an acyclic carbonate and a mixed solvent of a cyclic carbonate and an ether are more preferred. As a mixed solvent of a cyclic carbonate and an acyclic carbonate, a mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is preferred. A nonaqueous electrolyte using such a mixed solvent has the advantages of a wide operating temperature range, being resistant to deterioration even when used at high voltages and for long periods of time, and being difficult to decompose even when graphite materials such as natural graphite and artificial graphite are used as the negative electrode active material.

[0133] Furthermore, it is preferable to use a nonaqueous electrolyte solution containing a fluorine-containing lithium salt such as LiPF6 and an organic solvent having a fluorine substituent, as this increases the safety of the resulting nonaqueous electrolyte secondary battery. A mixed solvent containing dimethyl carbonate and an ether having a fluorine substituent, such as pentafluoropropyl methyl ether or 2,2,3,3-tetrafluoropropyl difluoromethyl ether, is more preferable, as it has a high capacity retention rate even when discharged at a high voltage.

[0134] <Members for non-aqueous electrolyte secondary batteries and methods for manufacturing non-aqueous electrolyte secondary batteries> As a method for producing a member for a non-aqueous electrolyte secondary battery, for example, there is a method in which a positive electrode, a laminated separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention, and a negative electrode are arranged in this order.

[0135] The following method can be used to manufacture a nonaqueous electrolyte secondary battery. First, a nonaqueous electrolyte secondary battery component is placed in a container that will serve as the housing of the nonaqueous electrolyte secondary battery. Next, the container is filled with a nonaqueous electrolyte, and then the container is sealed while reducing the pressure. This completes the manufacture of a nonaqueous electrolyte secondary battery.

[0136] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0137] An embodiment of the present invention may include the following features. <1> A composition for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising a resin having an amide bond and an aromatic ring, wherein the proportion of aromatic rings having a carboxy group relative to all aromatic rings in the resin is 0.2 to 2.0 mol %. <2> The resin is an aramid resin. <1> The composition described in <3> The aramid resin is Block A mainly composed of a unit represented by the following formula (1), -(NH-Ar 1 -NHCO-Ar 2 -CO)- Formula (1) Block B mainly composed of a unit represented by the following formula (2), -(NH-Ar 3 -NHCO-Ar 4 -CO)- Formula (2) and a block copolymer having the formula: <2> The composition described in (In formula (1) and formula (2), Ar 1 , Ar 2 , Ar 3 and Ar 4 may be different for each unit, Ar 1 , Ar 2 , Ar 3 and Ar 4 are each independently a divalent group having one or more aromatic rings, All Ar 1 More than 50% of these have a structure in which two aromatic rings are connected by a sulfonyl bond. All Ar 3 Of these, 50% or less have a structure in which two aromatic rings are connected by a sulfonyl bond, All Ar 1 and Ar 3 Of these, 10-70% have a structure in which two aromatic rings are linked by a sulfonyl bond. <4> The composition further contains a filler, and the content of the filler is 20 to 90% by weight based on the total amount of the resin and the filler. <1> ~ <3> The composition according to any one of the preceding claims. <5> <1> ~ <4> 10. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising the composition according to any one of 1 to 9. <6> A porous layer, <5> 2. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. <7> On one or both sides of the polyolefin porous film, <5> or <6> 10. A laminate separator for a non-aqueous electrolyte secondary battery, comprising a laminated layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 19. <8> An adhesive layer is further provided in addition to the polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery. <7> 2. The laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. <9> A positive electrode and <7> or <8> 10. A member for a non-aqueous electrolyte secondary battery, comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 1, and a negative electrode, arranged in this order. <10> <7> or <8> A non-aqueous electrolyte secondary battery comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. [Example]

[0138] EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0139] [Methods for measuring various physical properties] In the examples and comparative examples described below, the various physical properties were measured by the following methods.

[0140] [Calculation of the proportion of aromatic rings with carboxy groups] The amount of aromatic rings having carboxy groups in the synthesized aramid resin was measured using 1H-NMR under the following conditions: Equipment: PS400WB (Varian) Measurement temperature: 80℃ Number of times accumulated: 128 Concentration: 60mg / mL Solvent: Trifluoromethanesulfonic acid Chemical shift values ​​based on tetramethylsilane The amount of terminal carboxyl groups was calculated from the integral value (2) of the signal appearing at 7.1 ppm when the integral value (1) of the signal observed at 5.6 to 7.6 ppm was taken as 1.

[0141] The ratio of aromatic rings having a carboxy group to all aromatic rings was calculated by the following formula. Ratio of aromatic rings with carboxyl groups to all aromatic rings = signal integral value (2) × 2 [Rate discharge capacity retention rate] <Preparation of Test Non-Aqueous Electrolyte Secondary Batteries> Using the laminated separators obtained in the examples and comparative examples described below, non-aqueous electrolyte secondary batteries for testing were fabricated by the methods shown in 1. to 4. below. 1. A positive electrode and a negative electrode were prepared. The positive electrode had a thickness of 51 μm and a density of 2.95 g / cm. 3 The electrode hoop (JFE Techno Research Corporation) was used. The positive electrode active material was LiNi 0.8 Co 0.15 Al 0.05 The negative electrode had a thickness of 59 μm and a density of 1.45 g / cm. 3 An electrode hoop (JFE Techno Research Corporation) was used. The composition of the negative electrode active material was 96.5 parts by weight of artificial graphite, 2 parts by weight of binder, and 1.5 parts by weight of carboxymethyl cellulose. 2. A positive electrode, a laminated separator, and a negative electrode were laminated in this order in a laminate pouch to prepare a nonaqueous electrolyte secondary battery member. At this time, the separator was arranged so that (a) the porous layer of the laminated separator was in contact with the positive electrode active material layer of the positive electrode, and (b) the porous film of the laminated separator was in contact with the negative electrode active material layer of the negative electrode. 3. The nonaqueous electrolyte secondary battery component prepared in 2. was placed in a bag formed by laminating an aluminum layer and a heat seal layer, and 230 μL of nonaqueous electrolyte was poured into it. The nonaqueous electrolyte was prepared by dissolving vinylene carbonate and LiPF6 in a mixed solvent so that the concentration of vinylene carbonate was 1 wt % and the concentration of LiPF6 was 1 mol / L. The mixed solvent used was a 3:5:2 (volume ratio) mixture of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate. 4. The bag containing the nonaqueous electrolyte secondary battery components and the nonaqueous electrolyte in step 3 was heat-sealed while reducing the pressure inside the bag, thereby producing a nonaqueous electrolyte secondary battery for testing.

[0142] <Measurement of rate discharge capacity retention> The test nonaqueous electrolyte secondary battery was subjected to one initial charge / discharge cycle at 25° C. with a voltage range of 2.7 to 4.2 V and a current value of 0.1 C (charge) and 0.2 C (discharge). Here, the current value at which the rated capacity based on the one-hour rate discharge capacity is discharged in one hour is defined as 1 C, and the same applies below.

[0143] After initial charge and discharge, aging was carried out by performing 10 cycles of charge and discharge at a current value of 1C (charge) and 5C (discharge).

[0144] Next, the aged nonaqueous electrolyte secondary battery was subjected to 9 charge / discharge cycles at 25°C under the following conditions: charge current: 1.0 C, end voltage: 2.7 V, and discharge current: 0.2 C, 1 C, 2 C, 3 C, 4 C, 5 C, 6 C, 7 C, and 0.2 C. The charge capacity [mAh] and discharge capacity [mAh] under each condition were measured. The rate discharge capacity retention [%] was calculated according to the following formula using the discharge capacity at the initial charge / discharge (0.2 C) and the discharge capacity at the charge / discharge current of 5 C. Rate discharge capacity retention rate [%] = {Discharge capacity at 5C [mAh] / Discharge capacity at initial charge / discharge 0.2C [mAh]} × 100 [Air permeability] The air permeability of the laminated separator cut into a size of 60 mm x 60 mm was measured in accordance with JIS P8117 using a digital Oken type air permeability tester EGO1 manufactured by Asahi Seiko Co., Ltd.

[0145] [Weight per unit area] A square sample of 8 cm x 8 cm was cut out from the porous film. The weight of this sample was measured and designated as W1 [g]. The basis weight of the porous film was calculated according to the following formula (8). Weight of porous film [g / m 2 ]=W1[g] / (0.08×0.08) (8) An 8 cm x 8 cm square sample was cut out from the laminated separator. The weight of this sample was measured and designated as W2 [g]. The weight per unit area of ​​the laminated separator was calculated according to the following formula (9). Weight of laminated separator [g / m2 ]=W2[g] / (0.08×0.08) (9) The weight per unit area of ​​the porous layer was calculated by subtracting the weight per unit area of ​​the porous film from the weight per unit area of ​​the laminated separator.

[0146] [Production Example 1] Coating liquid (1) was prepared according to the following procedure: The aramid resin contained in coating liquid (1) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.76 g of 4,4'-diaminodiphenyl sulfone (DDS) was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.67 g of terephthalic acid dichloride (TPC) was added in three portions. The reaction was carried out for 1 hour to synthesize Block A1 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.002. 5. 61.74 g of paraphenylenediamine (PPD) was added to the flask and allowed to dissolve completely over 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.08 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing the poly(paraphenylene terephthalamide) block B1 to extend on both sides of the block A1. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (A) was obtained. In the block copolymer contained in aramid polymerization liquid (A), block A1 accounts for 50% of the entire molecule, and block B1 accounts for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (A) and mixed in such a way that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (1).

[0147] [Production Example 2] A slurry coating liquid (2) was prepared in the same manner as in Production Example 1, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 4:1.

[0148] [Production Example 3] Coating liquid (3) was prepared according to the following procedure: The aramid resin contained in coating liquid (3) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.61g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 116.13 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A2, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 0.997. 5. 61.67g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 112.96 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing the poly(paraphenylene terephthalamide) block B2 to extend on both sides of the block A2. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (B) was obtained. In the block copolymer contained in aramid polymerization liquid (B), block A2 accounts for 50% of the entire molecule, and block B2 accounts for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (B) and mixed so that the weight ratio of aramid resin to alumina was 2:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (3).

[0149] [Production Example 4] A slurry coating liquid (4) was prepared in the same manner as in Production Example 3, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 3:1.

[0150] [Production Example 5] Coating liquid (5) was prepared according to the following procedure: The aramid resin contained in coating liquid (5) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.70 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.86 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize block A3 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.00. 5. 61.71 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.03 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B3 (poly(paraphenylene terephthalamide)) to extend on both sides of block A3. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (C) was obtained. In the block copolymer contained in aramid polymerization liquid (C), block A3 accounted for 50% of the entire molecule, and block B3 accounted for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (C) and mixed. At this time, alumina was added so that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (5).

[0151] [Production Example 6] A slurry coating liquid (6) was prepared in the same manner as in Production Example 5, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 4:1.

[0152] [Production Example 7] Coating liquid (7) was prepared according to the following procedure: The aramid resin contained in coating liquid (7) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 800 ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.70 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 116.30 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize block A4 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 0.995. 5. 61.71 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.03 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B4 (poly(paraphenylene terephthalamide)) to extend on both sides of block A4. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (D) was obtained. In the block copolymer contained in aramid polymerization liquid (D), block A4 accounts for 50% of the entire molecule, and block B4 accounts for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (D) and mixed so that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (7).

[0153] [Comparative Production Example 1] Coating liquid (8) was prepared according to the following procedure: The aramid resin contained in coating liquid (8) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4202 g of NMP was charged into the flask. 365.9 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in a manner calculated to give a moisture content of 300 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.97 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 16°C. While maintaining the temperature of the polymerization system at 16±2°C, a total of 114.25 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A5, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.016. 5. 61.83 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 18±2°C, a total of 114.03 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B5 (poly(paraphenylene terephthalamide)) to extend on both sides of block A5. The molar ratio of PPD to TPC was 1.018. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (E) was obtained. In the block copolymer contained in aramid polymerization liquid (E), block A5 accounted for 50% of the entire molecule, and block B5 accounted for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (E) and mixed so that the weight ratio of aramid resin to alumina was 7:3. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixed solution obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (8).

[0154] [Comparative Production Example 2] A slurry coating liquid (9) was prepared in the same manner as in Comparative Production Example 1, except that in step 8 the weight ratio of aramid resin to alumina was changed to 4:1.

[0155] Example 1 Porous film (Porous polyethylene film, thickness: 9 μm, weight: 5 g / m 2 While conveying the porous film, the slurry coating liquid (1) prepared in Production Example 1 was coated on one side (surface) of the porous film. As a result, a coating film was formed on one side of the porous film. Then, while conveying the porous film on which the coating film was formed, the coating film and the porous film were passed through a precipitation tank set at 50°C and a relative humidity of 70%, and the coating film was exposed to air containing water vapor at 50°C and a relative humidity of 70%. This caused a block copolymer to precipitate on one side (surface) of the porous film, forming a coating layer. Next, a laminate consisting of the porous film and the coating layer precipitated on one side of the porous film was washed with water to remove calcium chloride and the solvent from the coating layer. The laminate was then dried to obtain a laminate separator (1) in which a porous layer was formed on one side of the porous film.

[0156] Example 2 A laminated separator (2) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (2) prepared in Production Example 2 was used instead of the slurry coating liquid (1).

[0157] Example 3 A laminated separator (3) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (3) prepared in Production Example 3 was used instead of the slurry coating liquid (1).

[0158] Example 4 A laminated separator (4) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (4) prepared in Production Example 4 was used instead of the slurry coating liquid (1).

[0159] Example 5 A laminated separator (5) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (5) prepared in Production Example 5 was used instead of the slurry coating liquid (1).

[0160] Example 6 The same operation as in Example 1 was carried out except that the slurry coating liquid (6) prepared in Production Example 6 was used instead of the slurry coating liquid (1), to obtain a laminated separator (6).

[0161] Example 7 The same operation as in Example 1 was carried out, except that the slurry coating liquid (7) prepared in Production Example 7 was used instead of the slurry coating liquid (1), to obtain a laminated separator (7).

[0162] Comparative Example 1 A laminated separator (8) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (8) prepared in Comparative Production Example 1 was used instead of the slurry coating liquid (1).

[0163] Comparative Example 2 A laminated separator (9) was obtained by the same procedure as in Example 1, except that the slurry coating liquid (9) prepared in Comparative Production Example 2 was used instead of the slurry coating liquid (1).

[0164] 〔result〕 The compositions and measurement results of Examples 1 to 7 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0165] [Table 1]

[0166] As shown in Table 1, the laminate separators (1) to (7) of Examples 1 to 7 were obtained using compositions in which the proportion of aromatic rings having a carboxy group relative to all aromatic rings in the resin was 0.2 to 2.0 mol%, while the laminate separators (8) and (9) of Comparative Examples 1 and 2 were obtained using compositions in which the proportion of aromatic rings having a carboxy group was less than 0.2 mol%. Furthermore, the laminate separators (1) to (7) of Examples 1 to 7 had lower air permeability and higher 5C discharge capacity retention rates than the laminate separators (8) and (9) of Comparative Examples 1 and 2. [Industrial Applicability]

[0167] One aspect of the present invention can be used in the manufacture of a non-aqueous electrolyte secondary battery.

Claims

1. The resin contains an amide bond and an aromatic ring, The composition for forming a laminate separator for a non-aqueous electrolyte secondary battery comprises a resin in which the proportion of aromatic rings having a carboxy group is 0.2 to 2.0 mol % relative to all aromatic rings in the resin.

2. The composition of claim 1 wherein the resin is an aramid resin.

3. The aramid resin is a block A mainly composed of a unit represented by the following formula (1); -(NH-Ar １ -NHCO-Ar ２ -CO)- Formula (1) a block B mainly composed of a unit represented by the following formula (2); -(NH-Ar ３ -NHCO-Ar ４ -CO)- Formula (2) The composition of claim 2 comprising a block copolymer having the formula: (In formula (1) and formula (2), Ar １ , Ar ２ , Ar ３ and Ar ４ may be different for each unit, Ar １ , Ar ２ , Ar ３ and Ar ４ are each independently a divalent group having one or more aromatic rings, All Ar １ More than 50% of these have a structure in which two aromatic rings are linked by a sulfonyl bond, All Ar ３ 50% or less of the above have a structure in which two aromatic rings are connected by a sulfonyl bond, All Ar １ and Ar ３ Of these, 10 to 70% have a structure in which two aromatic rings are linked by a sulfonyl bond.

4. Further comprising a filler, 2. The composition according to claim 1, wherein the content of the filler is 20 to 90% by weight based on the total amount of the resin and the filler.

5. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising the composition according to claim 1 .

6. The layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 5, which is a porous layer.

7. A laminate separator for a non-aqueous electrolyte secondary battery, comprising a polyolefin porous film and a layer for forming the laminate separator for a non-aqueous electrolyte secondary battery according to claim 5 laminated on one or both sides of the polyolefin porous film.

8. 8. The laminate separator for a non-aqueous electrolyte secondary battery according to claim 7, further comprising an adhesive layer in addition to the polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery.

9. A member for a non-aqueous electrolyte secondary battery, comprising a positive electrode, the laminate separator for a non-aqueous electrolyte secondary battery according to claim 7 or 8, and a negative electrode arranged in this order.

10. A non-aqueous electrolyte secondary battery comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 7 or 8.

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