Composition for forming laminated separator for non-aqueous electrolyte secondary battery and use thereof

Abstract

Provided is a composition for forming a laminated separator for a non-aqueous electrolyte secondary battery, the composition being capable of reducing the amount of increase in air permeability of the laminated separator and improving heat resistance. This composition for forming a laminated separator for a non-aqueous electrolyte secondary battery contains a resin having an amide bond, the resin having an amide bond containing a component eluted into N-methyl-2-pyrrolidone, and the amount of the component eluted into N-methyl-2-pyrrolidone is less than the amount of the component eluted into N-methyl-2-pyrrolidone relative to the weight of the entire resin having an amide bond. The content of the component eluted into N-methyl-2-pyrrolidone is greater than 25.0% by weight and 45.0% by weight or less, and the content of the component eluted into N-methyl-2-pyrrolidone is greater than 25.0% by weight and 45.0% by weight or less.

Description

Technical Field

[0001] This invention relates to compositions for forming laminated separators for non-aqueous electrolyte secondary batteries and their applications. Background Technology

[0002] Non-aqueous electrolyte secondary batteries, especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, portable information terminals, etc. due to their high energy density. In addition, they are currently being developed as automotive batteries.

[0003] As a separator for the non-aqueous electrolyte secondary battery, for example, laminated separators, which are formed by stacking porous layers such as heat-resistant layers on one or both sides of a polyolefin porous membrane, are conventionally used. Furthermore, in recent years, with the increasing capacity of batteries, the demand for laminated separators with high voltage resistance has increased. As a laminated separator that meets these demands, a laminated separator having the features shown in Patent Document 1 (a) and (b) has been developed: (a) Porous layers are stacked on one or both sides of a polyolefin porous membrane; (b) The porous layer comprises aramid resin and filler, wherein the aramid resin is a block copolymer having a structure in which some aromatic rings are linked to each other by sulfonyl bonds, specifically, a block copolymer having a structure in which there are blocks with more sulfonyl groups and blocks with fewer sulfonyl groups. [Existing Technical Documents] [Patent Literature]

[0004] Patent Document 1: JP 2022-42995 Summary of the Invention [The problem the invention aims to solve]

[0005] However, the existing technology described above has room for further improvement in terms of both the permeability and heat resistance of the laminated separator. One objective of this invention is to provide a composition for forming a laminated separator for non-aqueous electrolyte secondary batteries that can reduce the increase in permeability of the laminated separator and improve its heat resistance. [Methods used to solve problems]

[0006] To address the aforementioned problem, one aspect of the present invention provides a composition for forming a laminated separator for a non-aqueous electrolyte secondary battery, comprising a resin having amide bonds, wherein the resin having amide bonds contains a component dissolved in N-methyl-2-pyrrolidone, and the content of the component dissolved in N-methyl-2-pyrrolidone is greater than 25.0% by weight and less than 45.0% by weight relative to the total weight of the resin having amide bonds. [The effects of the invention]

[0007] According to one aspect of the present invention, a composition for forming a laminated separator for a non-aqueous electrolyte secondary battery can be provided, the composition being able to reduce the increase in air permeability of the laminated separator and improve heat resistance. Detailed Implementation

[0008] The present invention will be described with reference to one embodiment, but the invention is not limited thereto. It should be noted that, unless otherwise specified in this specification, "A to B" indicating a numerical range means "above A and below B".

[0009] [1. Composition for forming laminated separators for non-aqueous electrolyte secondary batteries] A composition for forming a laminated separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention contains a resin having amide bonds, wherein the resin having amide bonds contains a component dissolved in N-methyl-2-pyrrolidone, and the content of the component dissolved in N-methyl-2-pyrrolidone is greater than 25.0% by weight and less than 45.0% by weight relative to the total weight of the resin having amide bonds. Hereinafter, the laminated separator for a non-aqueous electrolyte secondary battery will also be simply referred to as a "laminated separator".

[0010] Here, the content of the component dissolved into N-methyl-2-pyrrolidone (NMP) can be obtained by performing an extraction operation using NMP on the resin having amide bonds, the composition containing the resin, or the layer containing the composition.

[0011] Typically, the permeability of a laminated membrane obtained by coating a substrate with a coating solution increases compared to the permeability of the substrate. On the other hand, the increase in permeability of a laminated membrane containing the composition decreases due to the size of its pores. This is because the component in the composition extracted by NMP has a high affinity for NMP, a solvent widely used in the coating solution. Regarding resins with amide bonds, typically after coating a substrate with a coating solution, the resin contained in the coating solution precipitates out, forming a network structure, thereby creating pores. Here, after components in the composition other than those dissolved in NMP precipitate out and form a network structure, components containing polar functional groups such as carboxyl groups and / or low-molecular-weight cyclic components, which are components in the composition dissolved in NMP, precipitate near this network structure. This precipitation results in a layer with large pores, and consequently, the increase in permeability of the laminated membrane containing the composition decreases.

[0012] Furthermore, due to the high content of polar functional groups such as carboxyl groups and / or low molecular weight cyclic components, the composition exhibits high affinity for general substrates in laminated separators for non-aqueous electrolyte secondary batteries, such as polyolefin porous membranes. Therefore, the adhesion between the layer containing the composition and the substrate is enhanced. Here, under high-temperature conditions, the layer with low heat resistance and prone to shrinkage due to heat among the two or more layers constituting the laminated separator, such as the substrate, begins to shrink first. At this time, by stacking other layers (e.g., the layer containing the composition) that are less prone to shrinkage due to heat on top of the easily shrinkable layer, the force resisting shrinkage acts, maintaining the overall shape of the laminated separator under high-temperature conditions. Here, when the adhesion between the substrate and the layer containing the composition is high, the force resisting shrinkage increases, resulting in improved heat resistance of the laminated separator containing the composition.

[0013] <1-1. Resins with amide bonds> The composition contains a resin having amide bonds. The composition contains at least one of the resins. That is, the resin may be a single resin or a mixture of two or more resins.

[0014] 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 by the chemical bonds. Therefore, the resin obtained by this preparation method can contain a high molecular weight chain polymer comprising a specific number or more of the divalent groups and a specific number or more of the chemical bonds. On the other hand, as a byproduct of this preparation method, by interrupting the linkage midway, a low molecular weight chain polymer with fewer divalent groups and fewer chemical bonds is generated compared to the high molecular weight chain polymer.

[0015] Furthermore, during the preparation of the resin, an intermediate product with fewer divalent groups and fewer chemical bonds is generated compared to the high molecular weight chain polymer. Here, a cyclic component is generated as another byproduct by the condensation of the two ends within the same molecule of the intermediate product. This cyclic component has a structure where the divalent groups are linked by the chemical bonds and it has no ends. The weight-average molecular weight of the cyclic component is also smaller than that of the high molecular weight chain polymer.

[0016] Specifically, in one embodiment of the present invention, the molecular weight of the low molecular weight chain polymer, expressed in terms of intrinsic viscosity, 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. Additionally, in one embodiment of the present invention, the molecular weight of the polymer constituting the cyclic component, expressed in terms of intrinsic viscosity, is preferably 0.1 to 3.0 dL / g, more preferably 0.3 to 1.5 dL / g.

[0017] Furthermore, in one embodiment of the present invention, the amide bond is a bond formed by the condensation of an amino group (-NH2) and a carboxylic acid halide (-C(=O)X) (where X is a halogen atom such as F, Cl, Br, I, etc.). Therefore, the resin having the amide bond may comprise a chain polymer with amino or carboxylic acid halide end groups. It should be noted that the carboxylic acid halide is slowly hydrolyzed by water in the solvent, producing hydrogen halides and carboxyl groups. Therefore, the resin having the amide bond may comprise a chain polymer with carboxyl groups at both ends. Chain polymers with carboxyl groups at the ends have low reactivity with amino groups, therefore the subsequent reaction of chain polymers with carboxyl groups at both ends stops, easily becoming low molecular weight chain polymers.

[0018] The low-molecular-weight chain polymers and the cyclic components have high solubility in organic solvents such as NMP due to their low weight-average molecular weight. Furthermore, chain polymers with carboxyl groups at both ends have higher solubility in organic solvents such as NMP compared to chain polymers with at least one amino group at the end. Therefore, when performing extraction operations using NMP on resins having amide bonds, compositions containing such resins, or layers containing such compositions, one or more components selected from the low-molecular-weight chain polymers, the cyclic components, and the chain polymers with carboxyl groups at both ends are extracted into the extract. In other words, in one embodiment of the present invention, the "component dissolved in NMP" is selected from one or more of the cyclic components, the chain polymers with carboxyl groups at both ends, and the low-molecular-weight chain polymers.

[0019] The weight of the resin with amide bonds, the composition containing the resin, or the layer containing the composition before and after the extraction operation is measured, and the difference is calculated as the weight of the "component dissolved in NMP" contained in the resin with amide bonds, the composition containing the resin, or the layer containing the composition. Alternatively, the weight of the "component dissolved in NMP" contained in the extract can also be determined by measuring the weight of the "component dissolved in NMP" contained in the resin with amide bonds, the composition containing the resin, or the layer containing the composition.

[0020] In the resin, from the perspective of the heat resistance of the layer containing the composition, the proportion of amide bonds in the chemical bonds is preferably 45-85%, more preferably 55-75%.

[0021] The divalent group is not particularly limited. In one embodiment of the 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.

[0022] In this specification, "divalent aromatic group" refers to a divalent group containing an unsubstituted aromatic ring or a substituted aromatic ring, preferably a divalent group composed of an unsubstituted aromatic ring or a substituted aromatic ring. An aromatic ring represents a cyclic compound that satisfies Hückel's rule. Examples of aromatic rings include benzene, naphthalene, anthracene, acridine, pyrrole, furan, and thiophene. In one embodiment of the invention, the aromatic ring consists only of carbon and hydrogen atoms. In another embodiment of the invention, the aromatic ring is a benzene ring or a fused ring of two or more benzene rings (naphthalene, anthracene, etc.).

[0023] In one embodiment of the present invention, the substituents in the divalent group are not particularly limited. In one embodiment of the present invention, from the perspective of obtaining a layer that is difficult to deteriorate even under high voltage conditions and has high voltage resistance, electron-withdrawing substituents are preferred as the substituents in the divalent group. The electron-withdrawing substituents are not particularly limited, and examples include carboxyl groups, alkoxycarbonyl groups, nitro groups, halogen atoms, etc.

[0024] The chemical bond may be only an amide bond, or it may contain bonds other than amide bonds. There is no particular limitation on the bonds other than amide bonds; examples include sulfonyl bonds, alkene bonds (e.g., C1-C5 alkene bonds), ether bonds, ester bonds, imide bonds, ketone bonds, and thioether bonds. There may be one type of bond other than amide bonds, or two or more types.

[0025] In one embodiment of the present invention, from the viewpoint of obtaining a layer with high voltage resistance, the bonds other than the amide bonds preferably include bonds with stronger electron-withdrawing properties than the amide bonds. Furthermore, from the viewpoint of further improving the high voltage resistance of the layer, the proportion of the chemical bonds with stronger electron-withdrawing properties than the amide bonds is more preferably 15-35%, and more preferably 25-35%.

[0026] Examples of bonds with stronger electron-withdrawing properties than amide bonds include sulfonyl bonds and ester bonds, among the chemical bonds listed above.

[0027] Specifically, the resin may include, for example, polyamides and polyamide-imides, as well as copolymers of polyamides or polyamide-imides with polymers having one or more bonds selected from sulfonyl bonds, ether bonds, and ester bonds. The copolymer may be a block copolymer or a random copolymer.

[0028] The polyamide is preferably an aromatic polyamide. Examples of aromatic polyamides include: fully aromatic polyamides (aramid resins) and semi-aromatic polyamides. Fully aromatic polyamides are preferred. Examples of aromatic polyamides include para-aramids and meta-aramids.

[0029] The polyamide-imide is preferably an aromatic polyamide-imide. Examples of the aromatic polyamide-imide include fully aromatic polyamide-imides and semi-aromatic polyamide-imides. Fully aromatic polyamide-imides are preferred.

[0030] Examples of polymers constituting the copolymer that have one or more bonds selected from the sulfonyl bond, ether bond, and ester bond include, for example, polysulfone, polyether, and polyester.

[0031] In one embodiment, the resin is preferably an aramid resin. The aramid resin is not particularly limited; for example, a resin comprising a block copolymer having a block A whose main component is a unit represented by formula (1) and a block B whose main component is a unit represented by formula (2) can be cited. -(NH-Ar 1 -NHCO-Ar 2 -CO)-(1) -(NH-Ar 3 -NHCO-Ar 4 -CO)-(2) (In equations (1) and (2), Ar) 1 Ar 2 Ar 3 and Ar 4 It can be different in each unit, Ar 1 Ar 2 Ar 3 and Ar 4 Each is an independent divalent group having one or more aromatic rings, all Ar 1 More than 50% of them have a structure with two aromatic rings linked by sulfonyl bonds, and all Ar 3 Less than 50% of them have a structure with two aromatic rings linked by sulfonyl bonds, and all Ar 1 and Ar 3 10-70% of them have a structure in which two aromatic rings are linked by sulfonyl bonds. In the block copolymer, the proportion of units of formula (1) in block A is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. All units in block A except for the ends are represented by units of formula (1). 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. All units in block B except for the ends are represented by units of formula (2).

[0032] In the segment A, at least a portion of Ar 1 It has a structure with two aromatic rings linked by sulfonyl bonds. In block B, Ar 3 It can have a structure with two aromatic rings linked by sulfonyl bonds. All Ar 1 and Ar 3 In Ar, which has a structure with two aromatic rings linked by sulfonyl bonds, 1 and Ar 3 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 the proportion is 70% or less, preferably 65% ​​or less, and more preferably 60% or less.

[0033] In the block A, all Ar 1 In Ar, which has a structure with two aromatic rings linked by sulfonyl bonds, 1 The proportion is 50% or more, preferably 80% or more, and more preferably 90% or more. In the block A, all Ar 1 It can have a structure in which two aromatic rings are linked by sulfonyl bonds.

[0034] In the block B, all Ar 3 In Ar, which has a structure with two aromatic rings linked by sulfonyl bonds, 3 The proportion is 50% or less, preferably 20% or less, and more preferably 10% or less. In the block B, all Ar 3 It can be a structure other than the structure in which two aromatic rings are linked by sulfonyl bonds.

[0035] Therefore, it can be said that block A is a block with relatively more sulfonyl groups, and block B is a block with relatively fewer sulfonyl groups. By using a block copolymer having two such blocks as the resin, a layer that can combine high voltage resistance and adhesion, as well as a laminated separator having such a layer, can be obtained.

[0036] The structure in which the two aromatic rings are connected by a sulfonyl bond is not particularly limited, and examples include 4,4'-diphenylsulfonyl, 3,4'-diphenylsulfonyl, 3,3'-diphenylsulfonyl, etc.

[0037] Examples of structures other than those in which the two aromatic rings are linked by sulfonyl bonds are not particularly limited; for example, structures such as those shown below can be cited.

[0038] [Chemical Formula 1]

[0039] At least a portion of the unit 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 in the unit 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 process, and the monomer is readily available.

[0040] At least a portion of the units of formula (2) contained in block B may be p-phenylene terephthalamide. In this case, the lower limit of the proportion of p-phenylene terephthalamide in 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. P-phenylene terephthalamide is easy to process and the monomer is readily available.

[0041] The block copolymer may have a structure consisting of units other than those represented by formulas (1) and (2). As an example of such a structure, a polyimide backbone can be cited.

[0042] The number of blocks in the block copolymer is not particularly limited. The block copolymer may, for example, have a diblock structure such as block A-block B, and a triblock structure such as block A-block B-block A and block B-block A-block B. Alternatively, the block copolymer may have a tetrablock structure such as block A-block B-block A-block B. Among these structures, a triblock structure of block B-block A-block B is preferred.

[0043] In the block copolymer 1 molecule, the number of units of formula (1) contained in block A is preferably 10 to 1000, more preferably 20 to 300. When the number of units of formula (1) is within this range, the molecule contains a sufficient number of sulfonyl groups, resulting in higher high-voltage resistance of the layer obtained from the composition and the laminated separator having the layer. In the block copolymer 1 molecule, the number of units of formula (2) contained in block B is preferably 10 to 500, more preferably 15 to 200. When the number of units of formula (2) is within this range, the adhesion of the layer obtained from the composition to other layers or electrodes is higher.

[0044] Here, the number of units in formulas (1) and (2) 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 obtained experimentally, for example, by gel permeation chromatography.

[0045] The molecular weight of the block copolymer, expressed as intrinsic viscosity, is preferably 0.5 to 5 dL / g, more preferably 0.8 to 2.5 dL / g. Within this molecular weight range, it can combine good coatability when forming layers from the composition with the strength of the resulting layers and the laminated membranes having those layers.

[0046] It should be noted that when the composition contains the block copolymer, its content is preferably 5 to 80% by weight, more preferably 10 to 60% by weight, based on 100% by weight of the solid components contained in the composition. When the content is within the range described above, the layer obtained from the composition and the laminated separator having the layer can be sufficiently endowed with high voltage resistance caused by the electron-withdrawing property of the sulfonyl group of the block copolymer.

[0047] From the perspective of reducing the increase in air permeability, the content of the component dissolved into the NMP in the composition is 25.0% by weight or more, preferably 28.0% by weight or more, and more preferably 30.0% by weight or more, relative to the total weight of the resin having amide bonds.

[0048] From a heat resistance perspective, the content of the component dissolved in NMP is 45.0% by weight or less, preferably 42.0% by weight or less, and more preferably 40.0% by weight or less, relative to the total weight of the resin containing amide bonds. Furthermore, the component dissolved in NMP has high solubility in the solvent and is difficult to precipitate. Therefore, if the composition contains an excessive amount of the component dissolved in NMP, it may be difficult for the composition to form a layer. From this perspective, the content of the component dissolved in NMP is preferably within the aforementioned range.

[0049] As the resin, it is preferable to select an aramid resin containing the block copolymer having the characteristics shown below. • Contains a large amount of homopolymers with the same structure as block A, and whose terminal monomers have low reactivity with other polymers, as well as cyclic components described later.

[0050] Hereinafter, the homopolymer having the same structure as block A and with low reactivity of the terminal monomers with other polymers will be referred to as "homogeneous polymer A". Furthermore, the aramid resin containing the block copolymer having the aforementioned characteristics will be referred to as "modified aramid resin". Homopolymer A and the cyclic component correspond to the components dissolved in NMP. Therefore, it can be said that, compared to conventional aramid resins, modified aramid resins contain more components dissolved in NMP.

[0051] It should be noted that homopolymer A is a byproduct that can be generated during the preparation of the block copolymer. Specifically, homopolymer A has a structure with a terminal carboxyl group: C(=O)-OH.

[0052] In addition, as another byproduct of the preparation of the block copolymer, a homopolymer having the same structure as block B and with low reactivity of the terminal monomers with other polymers can also be generated. Hereinafter, the homopolymer having the same structure as block B and with low reactivity of the terminal monomers with other polymers will be referred to as "homogeneous polymer B". Compared to block copolymers containing blocks A and B and homopolymer B, homopolymer A has a higher affinity for polyolefins commonly used as substrates in laminated membranes.

[0053] Furthermore, a portion of homopolymer A can be transformed into a cyclic component through bi-terminal condensation. Therefore, in addition to homopolymer A, aramid resins comprising the block copolymer may also contain the cyclic component. Similar to homopolymer A, the cyclic component also exhibits high affinity for polyolefins.

[0054] Therefore, the modified aramid resin contains a large amount of homopolymer A and the cyclic component, thus exhibiting high affinity for polyolefins. Consequently, when a composition containing modified aramid resin is used to form a layer on a polyolefin porous membrane, the laminated membrane exhibits excellent heat resistance, such as shape retention, under high-temperature conditions.

[0055] Furthermore, compared to block copolymers containing blocks A and B and homopolymer B, homopolymer A and the cyclic component have a higher affinity for solvents such as NMP commonly used in coating solutions. Therefore, homopolymer A and the cyclic component have high solubility in the solvent. Thus, in the case where a layer is formed from the composition, firstly, the block copolymer containing blocks A and B and homopolymer B precipitate, forming a network structure, and then homopolymer A precipitates near this network structure. This precipitation results in a layer with large pores, which in turn reduces the permeability of the layer and the laminated membrane containing it. Therefore, the laminated membrane with the layer containing the modified aramid resin has low permeability and excellent overall permeability.

[0056] The composition may contain fillers. When the composition contains fillers, and the total amount of the resin and the filler is 100% by weight, the filler content in the composition is preferably 20-90% by weight, more preferably 30-80% by weight. When the filler content is within the specified range, the layer obtained from the composition and the laminated membrane having the layer can have sufficient ion permeability. It should be noted that the composition may also be a composition without fillers, i.e., a filler content of 0% by weight.

[0057] Examples of the types of packing materials include organic packing materials, inorganic packing materials, and mixtures thereof.

[0058] Examples of the organic fillers include: copolymers of styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, etc., alone or in combination with two or more other types; fluorinated resins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polyvinylidene fluoride; melamine resin; urea resin; polyolefins; and polymethacrylates. The organic fillers can be used alone or in combination with two or more other types. From the perspective of chemical stability, polytetrafluoroethylene powder is preferred among these organic fillers. Furthermore, from the perspective of improving the shutdown performance of the laminated membrane, polyolefins can be used as organic fillers. When polyolefins are used as organic fillers, the layer obtained from the composition can be imparted with shutdown performance.

[0059] Examples of the inorganic fillers include materials containing inorganic substances such as metal oxides, metal nitrides, metal carbides, metal hydroxides, carbonates, and sulfates. Specifically, examples of inorganic fillers include powders such as aluminum oxides (alumina, etc.), boehmite, silicon dioxide, titanium dioxide, magnesium oxide, barium titanate, barium sulfate, magnesium hydroxide, aluminum hydroxide, and calcium carbonate; and minerals such as mica, zeolite, kaolin, and talc. Inorganic fillers can be used alone or in combination of two or more. Among these inorganic fillers, aluminum oxides are preferred from the perspective of chemical stability.

[0060] Regarding the shape of the filler, examples include approximately spherical, plate-like, columnar, needle-like, whisker-like, and fibrous shapes; particles of any shape can be used. From the perspective of easily forming uniform pores, the filler is preferably approximately spherical particles.

[0061] 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 larger tend to enlarge the fine pores within the layer obtained from the composition, thus minimizing the ion permeability of the laminated separator even when compressed within a battery using the composition containing this filler. Furthermore, since unevenness is easily formed on the surface of the layer obtained from the composition, the sliding properties of the laminated separator can be improved. On the other hand, when the average particle size of the filler is 1 μm or less, improved heat resistance and thin-film properties of the laminated separator can be achieved. To achieve both of these characteristics, fillers with different average particle sizes can be used, and fillers with a wide particle size distribution can also be used. In this specification, "average particle size of the filler" refers to the average particle size (D50) based on the volume of the filler. D50 refers to the particle size based on a cumulative distribution of 50% on a volume basis. D50 can be measured, for example, using a laser diffraction particle size analyzer (manufactured by Shimadzu Corporation, trade names: SALD2200, SALD2300, etc.).

[0062] The composition may contain other components besides the resin having amide bonds and the filler, without prejudice to the purpose of the invention. These other components may include, for example, resins other than the resin having amide bonds, and additives commonly used in separators for non-aqueous electrolyte secondary batteries. These other components may be one or a mixture of two or more.

[0063] Examples of resins other than those containing amide bonds include: polyolefins; (meth)acrylate resins; fluorinated resins; polyester resins; rubbers; resins with a melting point or glass transition temperature of 180°C or higher; water-soluble polymers; polycarbonates, polyacetals, polyetheretherketones, polybenzimidazoles, polyurethanes, melamine resins, etc. For example, by mixing a heat-resistant polyamide resin with an adhesive (meth)acrylate resin and / or a fluorinated resin, a layer possessing both heat resistance and adhesiveness can be obtained. In this case, the form in which the (meth)acrylate resin and / or the fluorinated resin exists is not particularly limited; it can be in particulate form, or it can exist in a mixed state with the polyamide resin, or it can segregate on the surface of the layer obtained from the composition.

[0064] The polyolefin is not particularly limited; examples include polyethylene, polypropylene, polybutene, and ethylene-propylene copolymers.

[0065] The (meth)acrylate resin is not particularly limited, and examples include methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

[0066] The fluorinated resin is not particularly limited, and examples 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-ethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, and ethylene-tetrafluoroethylene copolymer, as well as fluorinated rubbers in the fluorinated resin with a glass transition temperature of 23°C or less.

[0067] The polyester resin is not particularly limited; for example, aromatic polyesters and liquid crystal polyesters can be included. The aromatic polyester is not particularly limited; for example, polyarylates can be included.

[0068] Examples of rubbers include styrene-butadiene copolymers and their hydrides, methacrylate copolymers, acrylonitrile-acrylate copolymers, styrene-acrylate copolymers, ethylene propylene rubber, and polyvinyl acetate.

[0069] Examples of resins with a melting point or glass transition temperature of 180°C or higher include: polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyamideimide, polyetheramide, and polyetheretherketone.

[0070] Examples of water-soluble polymers include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, and polymethacrylic acid.

[0071] Examples of additives include flame retardants, antioxidants, surfactants, and waxes. If the layer obtained from the composition is prone to becoming charged, adding an antistatic agent can suppress this charging. Furthermore, adding flame retardants and / or crosslinking agents can further improve the safety and heat resistance of the membrane.

[0072] <1-2. Method for manufacturing the composition> The composition can be manufactured using a resin having amide bonds, such as the modified aramid resin. Furthermore, there are no particular limitations on the method for controlling the content of the component dissolved into NMP; for example, methods satisfying the manufacturing conditions shown in (i) and (ii) below can be cited.

[0073] The following describes a method for preparing the modified aramid resin. First, as a method for preparing an aramid resin containing the block copolymer, for example, a method following steps 1 and 2 below can be used. This method can prepare an aramid resin containing a block copolymer having a diblock structure of block A and block B. Alternatively, aramid resins containing block copolymers having other block structures can also be prepared using the following steps and manufacturing conditions. 1. Using NH2-Ar 1 -NH2 represents a diamine and X-(O=)C-Ar 2 Using dicarboxylic acid halides represented by -C(=O)-X (where X is a halogen atom such as F, Cl, Br, I, etc.) as monomers, polymerization was carried out according to a known method for the polymerization of aromatic polyamides. Thus, block A with units of formula (1) was synthesized. 2. After the synthesis of block A is completed, NH2-Ar is used. 3 -NH2 represents a diamine and is composed of X-(O=)C-Ar 4 A dicarboxylic acid halide represented by -C(=O)-X (where X is a halogen atom such as F, Cl, Br, I, etc.) was used as a monomer and polymerized according to a known method for the polymerization of aromatic polyamides. Thus, block B having the unit of formula (2) was synthesized in a state connected to block A.

[0074] Furthermore, in the method according to steps 1. and 2., a modified aramid resin suitable for the manufacture of the composition can be prepared by satisfying the manufacturing conditions shown in (i) and (ii) below. (i) In the synthesis of block A shown in 1, the water content of the solvent used is set to be higher than that in conventional manufacturing methods of the block copolymer, for example, preferably 150 ppm or more, more preferably 400 ppm or more, and even more preferably 450 ppm or more. Furthermore, the water content of the solvent is preferably 700 ppm or less, and even more preferably 600 ppm or less. (ii) In the synthesis of block A shown in 1, the addition ratio as the molar ratio of the diamine and 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.

[0075] Here, in the aramid resin containing block copolymers manufactured by the methods shown in 1. and 2., homopolymer A, homopolymer B, and the cyclic component may be contained as byproducts. The content of the cyclic component varies only with the concentration of the solids component during the synthesis of block A.

[0076] Under the condition described in (i), in step 1, the C(=O)-X (where X is a halogen atom such as F, Cl, Br, or I) terminal group of block A reacts with water molecules (H₂O), and this terminal group readily undergoes a reaction to become a carboxyl group: C(=O)-OH. Here, the carboxyl group corresponds to a group with low reactivity with monomers and other polymers. Therefore, the amount of homopolymer A contained in the block copolymer increases.

[0077] Therefore, under the condition described in (i), a modified aramid resin with a high content of homopolymer A and the cyclic component can be appropriately prepared.

[0078] On the other hand, when condition (i) is met, during the polymerization reaction that generates block A, the C(=O)-X group, which is the reaction site, tends to become a carboxyl group with low reactivity with monomers and other polymers. Therefore, when condition (i) is met, the weight-average molecular weight of the obtained modified aramid resin tends to decrease because the degree of polymerization of block A is reduced. Here, when the weight-average molecular weight of the modified aramid resin is low, in the method for manufacturing the laminated membrane, because the modified aramid resin has high solubility in the solvent and is difficult to precipitate, a layer cannot be formed from the composition, and the laminated membrane may not be able to be manufactured.

[0079] However, when the addition ratio is close to 1.00, the number of monomers as terminal groups of block A decreases, the degree of polymerization of block A increases, and thus the weight-average molecular weight of the obtained modified aramid resin increases. Therefore, by satisfying condition (ii), even when satisfying condition (i), the weight-average molecular weight of the obtained modified aramid resin can be increased to a degree that allows for the appropriate formation of a layer from the composition and the appropriate manufacture of the laminated membrane.

[0080] Furthermore, even if a layer can be formed from the composition, when the moisture content of the solvent is high, the weight-average molecular weight will decrease even if condition (ii) is met, thus sometimes resulting in a decrease in the heat resistance of the layer. As described above, by setting the moisture content of the solvent to 700 ppm or less, a layer with excellent heat resistance can be easily obtained.

[0081] [2. Layer for forming laminated separators for non-aqueous electrolyte secondary batteries] One embodiment of the present invention provides a layer for forming a laminated separator for a non-aqueous electrolyte secondary battery containing the composition. The layer is, for example, a porous layer.

[0082] The air permeability of the layer is preferably 400 s / 100 mL or less, more preferably 200 s / 100 mL or less. If the air permeability of the layer is within this range, the laminated membrane can be said to have sufficient ion permeability. In this specification, air permeability refers to the value measured using a Wang Yan-type air permeability tester according to JIS P8117.

[0083] For example, when the laminated diaphragm consists only of a polyolefin porous membrane and the layer, the air permeability of the polyolefin porous membrane is set as X, and the air permeability of the laminated diaphragm is set as Y, and calculated from YX.

[0084] From the perspective of controlling the air permeability within a preferred range, the weight per unit area of ​​the layer, i.e., the weight per unit area, is preferably 0.6 to 2.5 g / m². 2 More preferably, it is 0.8–2.0 g / m 2 .

[0085] The upper limit of the film thickness of the layer is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. Furthermore, the lower limit of the film 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.

[0086] [3. Laminated separator for non-aqueous electrolyte secondary batteries] According to one embodiment of the present invention, a laminated separator for a non-aqueous electrolyte secondary battery comprises a laminated separator forming layer thereof on one or both sides of a polyolefin porous membrane. That is, the laminated separator comprises a polyolefin porous membrane and the laminated separator forming layer thereof on one or both sides of the polyolefin porous membrane. Hereinafter, the polyolefin porous membrane will be simply referred to as a "porous membrane". The laminated separator forming layer thereof also contains the aforementioned composition.

[0087] The air permeability of the laminated membrane is preferably below 500 s / 100 mL, more preferably below 300 s / 100 mL. When the air permeability of the laminated membrane is within this range, it can be said that the laminated membrane has sufficient ion permeability.

[0088] The layer containing the composition may be disposed on one side of the porous membrane or on both sides of the porous membrane. Furthermore, the membrane thickness, weight per unit area, and porosity of one layer containing the composition and the other layer containing the composition disposed on both sides of the porous membrane may be the same or different.

[0089] <3-1.Porous membrane> Porous membranes have multiple interconnected pores within them, allowing gas and liquid to pass through from one side to the other. Porous membranes can serve as substrates for laminated separators. When the battery heats up, the porous membrane melts, rendering the laminated separator non-porous, thereby imparting a cut-off function to the laminated separator.

[0090] Here, "polyolefin porous membrane" refers to a porous membrane whose main component is a polyolefin resin. In addition, "polyolefin resin as the main component" means that the proportion of polyolefin resin in the porous membrane is 50% or more by volume of the total material constituting the porous membrane, preferably 90% or more by volume, and more preferably 95% or more by volume.

[0091] The polyolefin resin used as the main component of the porous membrane is not particularly limited. Examples include homopolymers and copolymers formed from monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and / or 1-hexene, which are thermoplastic resins. Specifically, examples of homopolymers include polyethylene, polypropylene, and polybutene, while examples of copolymers include ethylene-propylene copolymers. The porous membrane can be a layer containing only these polyolefin resins or a layer containing two or more of these polyolefin resins. Polyethylene is preferred because it can prevent (cut off) excessive current flow at lower temperatures, and high molecular weight polyethylene with ethylene as the main component is particularly preferred. It should be noted that the polyolefin porous membrane may contain components other than polyolefins, provided that its function is not impaired.

[0092] 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 further preferred, and polyethylene containing a weight-average molecular weight of 5 × 10⁻⁶ is even more preferred. 5 ~15×10 6 High molecular weight components. In particular, when polyolefin resins contain high molecular weight components with a weight-average molecular weight of 1 million or more, the strength of porous membranes and laminated membranes is improved, and therefore they are more preferred.

[0093] Porous membranes can be multilayer structures consisting of two or more layers. Examples of multilayer porous membranes include those with layers primarily composed of polyethylene and layers primarily composed of polypropylene. The number of layers is not particularly limited; it can be two layers composed of polyethylene and polypropylene, or three layers composed of a combination of polyethylene and polypropylene. By employing a multilayer structure of polyethylene and polypropylene, both cutability and heat resistance can be achieved.

[0094] The porous membrane may have a cross-linked structure. This cross-linked structure can be introduced, for example, by using silane-modified polyolefins. Because the porous membrane with the cross-linked structure exhibits excellent heat resistance, the heat resistance of the laminated membrane can be further improved by combining it with a layer containing the composition. It should be noted that the cross-linked structure can be formed between the porous membrane and the layer containing the composition.

[0095] The thickness of the porous membrane is preferably 3 to 20 μm, more preferably 4 to 15 μm, and even more preferably 4.5 to 15 μm. A membrane thickness of 3 μm or more ensures the strength of the laminated membrane. Furthermore, a membrane thickness of 3 μm or more adequately provides the required functions (such as cutting-off function). A membrane thickness of 20 μm or less allows for the acquisition of thin laminated membranes.

[0096] The pore size of the porous membrane is preferably 0.1 μm or less, more preferably 0.06 μm or less. This ensures sufficient ion permeability and further prevents the entry of particles constituting the electrode.

[0097] To improve the gravimetric and volumetric energy density of the battery, the weight per unit area of ​​the porous membrane is typically preferred to be 2–20 g / m². 2 More preferably 2.5–12 g / m 2 .

[0098] The air permeability of the porous membrane is preferably 30–500 s / 100 mL, more preferably 50–300 s / 100 mL. Therefore, the laminated membrane can achieve sufficient ion permeability.

[0099] The porosity of the porous membrane is preferably 20 to 80% by volume, more preferably 30 to 75% by volume. This improves the retention of electrolyte and reliably prevents excessive current flow at lower temperatures.

[0100] The manufacturing method of porous membranes can use known methods and is not particularly limited. For example, as described in Japanese Patent No. 5476844, a method is used to remove the filler after forming a membrane by adding a filler to a thermoplastic resin.

[0101] Specifically, for example, when the porous membrane is formed from a polyolefin resin containing ultra-high molecular weight polyethylene and low molecular weight polyolefin with a weight average molecular weight of less than 10,000, from the perspective of manufacturing cost, it is preferable to manufacture it by a method including the steps (1) to (4) shown below: (1) The process of mixing 100 parts by weight of ultra-high molecular weight polyethylene, 5 to 200 parts by weight of low molecular weight polyolefin with a weight average molecular weight of less than 10,000, and 100 to 400 parts by weight of inorganic fillers such as calcium carbonate to obtain a polyolefin resin composition. (2) A process of forming sheets using a polyolefin resin composition; (3) The process of removing inorganic fillers from the sheet obtained from process (2); (4) The process of stretching the sheet obtained in process (3). In addition, the methods described in the aforementioned patent documents can also be used.

[0102] <3-2. Other Functional Layers> As needed, and without prejudice to the purpose of the invention, the laminated diaphragm may contain other functional layers different from the porous membrane and the layer containing the composition. Examples of other functional layers include: adhesive layers, heat-resistant porous layers different from the layer containing the composition, slip-resistant layers for improving the sliding properties of the diaphragm, layers containing organic particles such as polyolefins for imparting cutability, antistatic layers, protective layers, and other known porous layers. For example, in addition to the porous membrane and the layer containing the composition, the laminated diaphragm may also contain other functional layers as needed, and without prejudice to the purpose of the invention. A heat-resistant porous layer different from the layer containing the composition refers to a layer where the type of resin and filler, and the amount of filler, are different from those in the layer containing the composition. When other functional layers are heat-resistant porous layers different from the layer containing the composition, the resin and filler, and the amount of filler exemplified in the composition, can be used in these other functional layers. The slip layer is a layer containing an anti-blocking agent or a layer containing fillers, etc. By setting the surface unevenness, the sliding property of the diaphragm can be improved.

[0103] Other functional layers may be disposed on one or both sides of the laminated separator. When the laminated separator has layers containing the composition on both sides of the porous membrane, the other functional layers may be disposed on the layers containing the composition on both sides, or on a single side of the layer containing the composition. When the laminated separator has a layer containing the composition only on one side of the porous membrane, the other functional layers may be disposed on the layer containing the composition, or on the side of the porous membrane that does not have a layer containing the composition. The other functional layers may be disposed on the outermost layer of the laminated separator.

[0104] For example, the laminated diaphragm further comprises an adhesive layer different from the porous membrane and the layer containing the composition. In this specification, an adhesive layer refers to a layer with adhesive properties. The adhesive layer may be provided on the electrode-contacting surface of the laminated diaphragm. Examples of adhesive components in the adhesive layer that contribute to adhesion include acrylic resins and PVDF resins. For example, the acrylic resin described in paragraphs

[0072] to

[0088] of Japanese Patent Application Publication No. 2024-006988 may be used. For example, the PVDF resin described in paragraphs

[0017] to

[0022] of Japanese Patent Application Publication No. 2017-168419 may be used. Acrylic resins and PVDF resins may be used individually or in combination. In addition to the adhesive components, the adhesive layer may also include fillers. The same fillers as those added to the composition may be used as fillers. The state of the adhesive layer is not particularly limited; the components that contribute to adhesion can be present in particulate form or as a uniform coating layer. Furthermore, the adhesive layer can be patterned to present in a dotted or striped pattern. By providing this adhesive layer, the laminated separator is fixed to the electrode, thereby improving the operability and heat resistance of the electrode laminate. Furthermore, by presenting the adhesive layer in particulate, dotted, or striped form, the reduction in ion permeability of the laminated separator can be suppressed.

[0105] <3-3. Manufacturing methods of layers and laminated diaphragms> For example, the laminated membrane can be manufactured by forming a layer on one or both sides of the porous membrane 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 used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide. It should be noted that the solvent can also be described as a dispersion medium in which the components constituting the composition are dispersed.

[0106] As a method for manufacturing the laminated membrane, for example, one could include: preparing the coating solution, applying the coating solution onto a porous membrane, drying it, thereby forming a layer containing the composition on the porous membrane. In this method of manufacturing the layer, the object onto which the coating solution is applied is not limited to a porous membrane; other membranes, positive electrodes, and negative electrodes can also be used.

[0107] As a method for coating the coating liquid onto the porous membrane, known coating methods such as blade coating, scraper coating, bar coating, gravure coating, or die coating can be used.

[0108] The solvent removal method is generally through drying. Examples of drying methods include natural drying, forced-air drying, heating drying, and reduced-pressure drying; any method can be used as long as the solvent is sufficiently removed. Alternatively, the solvent in the coating can be replaced with another solvent before drying. Specifically, methods involving replacing or precipitating the solvent with low-boiling-point, undesirable solvents such as water, alcohols, or acetone, followed by drying, are common approaches.

[0109] [4. Components for non-aqueous electrolyte secondary batteries and non-aqueous electrolyte secondary batteries] In one embodiment of the present invention, a component for a non-aqueous electrolyte secondary battery comprises a positive electrode, the aforementioned laminated separator, and a negative electrode arranged sequentially. Furthermore, another embodiment of the present invention includes the aforementioned laminated separator in a non-aqueous electrolyte secondary battery.

[0110] The non-aqueous electrolyte secondary battery typically has a structure in which a negative electrode and a positive electrode are separated by a stacked separator. In the non-aqueous electrolyte secondary battery, the battery elements impregnated with electrolyte within this structure are encapsulated within an outer casing material. For example, the non-aqueous electrolyte secondary battery is a lithium-ion secondary battery whose electromotive force is obtained through lithium-ion doping and dedoping.

[0111] Positive electrode As the positive electrode, for example, a positive electrode sheet with a structure having an active material layer containing a positive electrode active material and a binder formed on the current collector can be used. It should be noted that the active material layer may further contain a conductive agent.

[0112] As the positive electrode active material, for example, materials capable of doping and dedoping lithium ions can be cited.

[0113] Examples of such materials include lithium composite oxides containing at least one transition metal such as V, Ti, Cr, Mn, Fe, Co, Ni, or Cu. Examples of lithium composite oxides include lithium composite oxides with layered structures, lithium composite oxides with spinel structures, and solid solutions of lithium transition metal oxides containing both layered and spinel structures. Other examples include lithium-cobalt composite oxides and lithium-nickel composite oxides. Furthermore, examples include substances obtained by replacing a portion of the transition metal atoms that constitute the main body of these lithium composite oxides 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.

[0114] Lithium composite oxides obtained by replacing the transition metal atoms that will become the main body of the lithium composite oxide with other elements, for example, include: lithium cobalt composite oxide with a layered structure represented by the following formula (3), lithium nickel composite oxide represented by the following formula (4), lithium manganese composite oxide with a spinel structure represented by the following formula (5), and lithium-containing transition metal oxides in solid solution represented by the following formula (6).

[0115] Li[Li x (Co 1-a M 1 a ) 1-x O2···Formula (3) (In equation (3), M) 1 It is at least one metal selected from Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, satisfying -0.1 ≤ x ≤ 0.30 and 0 ≤ a ≤ 0.5. Li[Li y (Ni 1-b M 2 b ) 1-y O2···Formula (4) (In equation (4), M) 2 It is at least one metal selected from Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, satisfying -0.1 ≤ y ≤ 0.30 and 0 ≤ b ≤ 0.5. Li z Mn 2-c M 3 c O4···Formula (5) (In equation (5), M) 3 It is at least one metal selected from Na, K, B, F, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, satisfying 0.9 ≤ z and 0 ≤ c ≤ 1.5. Li 1+w M 4 d M 5 e O2···Formula (6) (In equation (6), M) 4 and M 5 It is at least one metal selected from Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg, and Ca, satisfying 0 <w≤1 / 3,0≤d≤2 / 3,0≤e≤2 / 3,w+d+e=1。) Specific examples of lithium composite oxides represented by formulas (3) to (6) include: LiCoO2, LiNiO2, LiMnO2, and LiNi 0.8 Co 0.2 O2, LiNi 0.5 Mn 0.5 O2, LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.8 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 Co0.08 Mn 0.50 O2, Li 1.07 Ni 0.36 Co 0.08 Mn 0.49 O2, etc.

[0116] Furthermore, lithium composite oxides other than those represented by formulas (3) to (6) can also be preferably used as positive electrode active materials. Examples of such lithium composite oxides include LiNiVO4, LiV3O6, and Li 1.2 Fe 0.4 Mn 0.4 O2, etc.

[0117] As a material that can be preferred as a positive electrode active material other than lithium composite oxide, for example, phosphates with an olivine-type structure can be cited, and phosphates with an olivine-type structure represented by the following formula (7) can be cited.

[0118] Li v (M 6 f M 7 g M 8 h M 9 i ) j PO4···Equation (7) (In equation (7), M) 6 For Mn, Co, or Ni, M 7 For Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb or Mo, M 8 M is any transition metal or main group element (typical element) excluding elements in Groups VIA and VIIA. 9 (A transition metal or main group element, excluding any element in Groups VIA and VIIA, that satisfies 1.2 ≥ a ≥ 0.9, 1 ≥ b ≥ 0.6, 0.4 ≥ c ≥ 0, 0.2 ≥ d ≥ 0, 0.2 ≥ e ≥ 0, and 1.2 ≥ f ≥ 0.9.) Regarding the positive electrode active material, it is preferable that a coating layer is formed 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, with metal composite oxides being preferred.

[0119] As the metal composite oxide, an oxide with lithium-ion conductivity is preferably used. Examples of such metal composite oxides include Li and metal composite oxides of at least one element selected from Nb, Ge, Si, P, Al, W, Ta, Ti, S, Zr, Zn, V, and B. When the positive electrode active material has a coating layer, this coating layer can suppress side reactions at the interface between the positive electrode active material and the electrolyte under high voltage, thereby achieving a long lifespan for the resulting secondary battery. Furthermore, the formation of a high-resistivity layer at the interface between the positive electrode active material and the electrolyte can be suppressed, resulting in a high output of the resulting secondary battery.

[0120] Examples of conductive agents include natural graphite, artificial graphite, coke, carbon black, thermally decomposed carbon, carbon fiber, sintered organic polymer compounds, and other carbonaceous materials.

[0121] Examples of such adhesives include, for instance, polyvinylidene fluoride (PVDF), copolymers of PVDF, polytetrafluoroethylene (PTFE), copolymers of PVDF-hexafluoropropylene, copolymers of tetrafluoroethylene-hexafluoropropylene, copolymers of tetrafluoroethylene-perfluoroalkyl vinyl ethers, copolymers of ethylene-tetrafluoroethylene, copolymers of PVDF-tetrafluoroethylene, copolymers of PVDF-trifluoroethylene, copolymers of PVDF-trichloroethylene, copolymers of PVDF-ethylene, copolymers of PVDF-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimides, thermoplastic resins such as polyethylene and polypropylene, acrylic resins, and styrene-butadiene rubber. It should be noted that the adhesive also functions as a thickener.

[0122] Examples of conductors that can be used as positive electrode current collectors include Al, Ni, and stainless steel. Among these, Al is preferred because it is easy to process into thin films and is inexpensive.

[0123] Methods for manufacturing sheet-like positive electrodes include, for example, a method of pressing a positive electrode active material, a conductive agent, and a binder (which will become a positive electrode mixture) onto a positive electrode current collector; or a method of using a suitable organic solvent to make a paste from the positive electrode active material, the conductive agent, and the binder, obtaining a positive electrode mixture, coating the positive electrode mixture onto a positive electrode current collector, drying it to obtain a sheet-like positive electrode mixture, and then pressing the positive electrode mixture onto the positive electrode current collector.

[0124] <Negative electrode> As a negative electrode, for example, a negative electrode sheet with a structure having an active material layer containing a negative electrode active material and a binder formed on a current collector can be used. It should be noted that the active material layer may further contain a conductive agent.

[0125] Examples of negative electrode active materials include carbon materials, chalcogenides (oxides, sulfides, etc.), nitrides, metals or alloys, and materials capable of lithium-ion doping and dedoping at a lower potential than that of the positive electrode.

[0126] Carbon materials that can be used as negative electrode active materials include natural graphite, artificial graphite, coke, carbon black, thermally decomposed carbon, carbon fiber, and sintered organic polymer compounds.

[0127] Oxides that can be used as negative electrode active materials include, for example, SiO2, SiO, etc. x (where x is a positive real number) represents the oxide of silicon; TiO2, TiO, etc. x (where x is a positive real number) represents the oxide of titanium; V₂O₅, VO₂, etc. x O y (where x and y are positive real numbers) represents vanadium oxides; Fe3O4, Fe2O3, FeO, etc. x O y (where x and y are positive real numbers) represents iron oxides; SnO2, SnO, etc. x (where x is a positive real number) represents tin oxides; WO3, WO2, etc., are general formulas for tin oxides. x (where x is a positive real number) represents the oxide of tungsten; Li4Ti5O 12 LiVO2 and other composite metal oxides containing lithium and titanium or vanadium; etc.

[0128] Sulfides that can be used as negative electrode active materials include, for example: Ti₂S₃, TiS₂, TiS, etc. x S y (where x and y are positive real numbers) represents titanium sulfides; V3S4, VS2, VS, etc. x (where x is a positive real number) represents vanadium sulfides; Fe3S4, FeS2, FeS, etc. x S y (where x and y are positive real numbers) represents iron sulfides; Mo2S3, MoS2, etc. x S y (where x and y are positive real numbers) represents the molybdenum sulfide; SnS2, SnS, etc. x (where x is a positive real number) represents tin sulfides; WS2 equation WS x (where x is a positive real number) represents tungsten sulfides; Sb2S3 equation Sb x S yAntimony sulfides represented by (where x and y are positive real numbers); sulfides of selenium such as Se5S3, SeS2, SeS, etc. x S y Sulfides of selenium represented by (where x and y are positive real numbers); etc.

[0129] As nitrides that can be used as negative electrode active materials, for example, Li3N, Li 3-x A x Li-containing nitrides such as N (where A is any one or both of Ni and Co, 0 < x < 3).

[0130] These carbon materials, oxides, sulfides, and nitrides can be used alone or in combination of two or more. In addition, these carbon materials, oxides, sulfides, and nitrides can be either crystalline or amorphous. These carbon materials, oxides, sulfides, and nitrides are mainly supported on the negative electrode current collector and used as electrodes.

[0131] In addition, as metals that can be used as negative electrode active materials, lithium metal, silicon metal, tin metal, etc. can be cited.

[0132] In addition, composites can be cited: composites having Si or Sn as the first constituent element and containing at least a second and a third constituent element in addition. 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.

[0133] In particular, from the perspective of obtaining a high battery capacity and excellent battery characteristics, as the metal material, elemental silicon or tin (which may contain trace impurities), SiO v (0 < v ≤ 2), SnO w (0 ≤ w ≤ 2), Si-Co-C composites, Si-Ni-C composites, Sn-Co-C composites, Sn-Ni-C composites are preferred.

[0134] As negative electrode current collectors, for example, Cu, Ni, stainless steel, etc. can be cited. Among them, especially in lithium ion secondary batteries, Cu is more preferred from the perspective of being difficult to form lithium alloys and being easily processed into thin films.

[0135] As a method for manufacturing a sheet-like negative electrode, for example, a method of press-molding a negative electrode active material that becomes a negative electrode mixture on a negative electrode current collector; after making a paste of the negative electrode active material using an appropriate organic solvent to obtain a negative electrode mixture, coating the negative electrode mixture on the negative electrode current collector, drying it to obtain a sheet-like negative electrode mixture, and pressing the negative electrode mixture to fix it on the negative electrode current collector, etc. The paste preferably contains the conductive agent and the binder.

[0136] <Non-aqueous electrolyte> As a non-aqueous electrolyte, for example, a non-aqueous electrolyte prepared by dissolving a lithium salt in an organic solvent can be used. 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 (where BOB is bis(oxalato)borate), lower aliphatic carboxylic acid lithium salts, LiAlCl4, etc. These can be used alone or as a mixture of two or more. Among them, as lithium salts, it is preferred to use lithium salts containing at least one of the following: LiPF6, LiAsF6, LiSbF6, LiBF4, LiSO3F, LiCF3SO3, LiN(SO2CF3)2, and LiC(SO2CF3)3.

[0137] Examples of organic solvents include: propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, 4-trifluoromethyl-1,3-dioxolan-2-one, 1,2-di(methoxycarbonyloxy)ethane, and other carbonates; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl dimethoxypropane, etc. Ethers such as fluoromethyl ethers, 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-oxazolidinone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 1,3-propanesulfonyl lactone; or solvents that further introduce fluorine groups into these organic solvents (solvents in which one or more hydrogen atoms of the organic solvent are replaced by fluorine atoms).

[0138] Regarding the organic solvents, it is preferable to use a mixture of two or more as a mixed solvent. Preferably, the mixed solvent contains carbonates, and more preferably, a mixed solvent of cyclic and non-cyclic carbonates, or a mixed solvent of cyclic carbonates and ethers. As a mixed solvent of cyclic and non-cyclic carbonates, a mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is preferred. Non-aqueous electrolytes using such mixed solvents have advantages such as a wide operating temperature range, resistance to degradation even under high voltage, resistance to degradation even after prolonged use, and poor decomposition resistance when using graphite materials such as natural graphite or artificial graphite as the active material of the negative electrode.

[0139] Furthermore, to improve the safety of the resulting non-aqueous electrolyte secondary battery, a non-aqueous electrolyte containing fluorinated lithium salts such as LiPF6 and organic solvents with fluorine substituents is preferred. Since the discharge capacity retention is high even at high voltages, a mixed solvent containing fluorinated ethers such as pentafluoropropyl methyl ether and 2,2,3,3-tetrafluoropropyl difluoromethyl ether, and dimethyl carbonate is further preferred.

[0140] <Components for Non-Aqueous Electrolyte Secondary Batteries and Manufacturing Methods for Non-Aqueous Electrolyte Secondary Batteries> As a method for manufacturing components for non-aqueous electrolyte secondary batteries, for example, a method of sequentially arranging a positive electrode, a laminated separator for non-aqueous electrolyte secondary batteries according to an embodiment of the present invention, and a negative electrode can be cited.

[0141] Furthermore, as a method for manufacturing a non-aqueous electrolyte secondary battery, the following method can be cited as an example. First, the non-aqueous electrolyte secondary battery component is placed in a container that serves as the frame of the non-aqueous electrolyte secondary battery. Next, the container is filled with non-aqueous electrolyte, and then the container is sealed while depressurizing. This allows the manufacture of a non-aqueous electrolyte secondary battery.

[0142] This invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of this invention.

[0143] One embodiment of the present invention may include the following configuration. <1> A composition for forming a laminated separator for a non-aqueous electrolyte secondary battery, the composition comprising a resin having amide bonds, the resin having amide bonds containing a component dissolved in NMP, wherein the content of the component dissolved in NMP is greater than 25.0% by weight and less than 45.0% by weight relative to the total weight of the resin having amide bonds. <2> according to <1> The composition wherein the resin is an aramid resin. <3> according to <2> The composition, wherein, The aramid resin comprises a block copolymer. The block copolymer has: Block A, whose main components are the units represented by the following equation (1), -(NH-Ar 1 -NHCO-Ar 2 -CO)- Equation (1), and Block B, whose main component is a unit represented by the following equation (2), -(NH-Ar 3 -NHCO-Ar 4 -CO)- Equation (2), (In equations (1) and (2),) Ar 1 Ar 2 Ar 3 and Ar 4 It can differ in each unit. Ar 1 Ar 2 Ar 3 and Ar 4 Each is independently a divalent group having one or more aromatic rings. All Ar 1 More than 50% of them have a structure in which two aromatic rings are linked by sulfonyl bonds. All Ar 3 Less than 50% of them have a structure with two aromatic rings linked by sulfonyl bonds. All Ar 1 and Ar 3 10-70% of them have a structure in which two aromatic rings are linked by sulfonyl bonds. <4> according to <1> ~ <3> The composition according to any one of the following methods, wherein the composition further comprises a filler, the filler content being 20-90% by weight relative to the total amount of the resin and the filler. <5> A layer for forming a laminated separator for a non-aqueous electrolyte secondary battery, comprising: <1> ~ <4> The composition described in any one of the following statements. <6> according to <5> The layer for forming a laminated separator for a non-aqueous electrolyte secondary battery is a porous layer. <7> A laminated separator for a non-aqueous electrolyte secondary battery comprises laminated separators on one or both sides of a polyolefin porous membrane. <5> or <6> The aforementioned non-aqueous electrolyte secondary battery uses a laminated separator forming layer. <8> according to <7> The laminated separator for non-aqueous electrolyte secondary batteries, in addition to the polyolefin porous membrane and the layer for forming the laminated separator for non-aqueous electrolyte secondary batteries, also includes an adhesive layer. <9> A component for a non-aqueous electrolyte secondary battery, comprising a positive electrode, a... <7> or <8> The non-aqueous electrolyte secondary battery uses a stacked separator and a negative electrode. <10> A non-aqueous electrolyte secondary battery, comprising <7> or <8> The aforementioned non-aqueous electrolyte secondary battery uses a laminated separator. [Example]

[0144] An embodiment of the present invention will be described below.

[0145] The present invention will be further described in detail below with reference to embodiments and comparative examples, but the present invention is not limited to these embodiments.

[0146] [Methods for determining various physical properties] In the examples and comparative examples described later, each property was determined by the following method.

[0147] [Content of components dissolved into NMP] Add 0.5 L of deionized water to the flask. Separately, measure 50 mL of the aramid polymerization solution obtained in the examples and comparative examples described later. Then, add the measured 50 mL of the aramid polymerization solution to the flask to precipitate the aramid resin. Filter the solution after precipitating the aramid resin once, add 100 mL of deionized water to the precipitate, and filter again. That is, perform two filtrations. Thus, 3.50 g of aramid resin is obtained.

[0148] 0.10 g of the aramid resin was weighed. This 0.10 g of aramid resin was then immersed in 100 mL of NMP in a vial. After appropriate stirring, the extract was filtered through a PTFE membrane filter with a pore size of 0.45 μm after 5 days, yielding filtrate A. Conversely, 1 g of the aramid polymerization solution was diluted with 69 g of NMP to obtain aramid resin containing the same weight as the resin immersed in NMP. This diluted filtrate B was then filtered through a PTFE membrane filter with a pore size of 0.45 μm. Filtrate A and filtrate B were analyzed by size exclusion chromatography (SEC) under the following conditions: The apparatus was equivalent to the LC-20A manufactured by Shimadzu Corporation; the column consisted of two TSK-GEL SUPER AWM-H columns manufactured by Tosoh Corporation; NMP containing 5 wt% CaCl2 was used as the eluent; the flow rate was 0.4 mL / min; the column temperature was 40 °C; and the detection wavelength was UV 310 nm. Based on the chromatograms obtained from filtrate A and filtrate B respectively, calculate the "area value of the aramid resin impregnation solution" and the "area value of the reference solution". It should be noted that the "area value of the aramid resin impregnation solution" is the area value in the chromatogram obtained using filtrate A, and the "area value of the reference solution" is the area value in the chromatogram obtained using filtrate B.

[0149] Using the “area value of aramid resin impregnation liquid” and the “area value of reference solution” obtained through the above operations, the content of the component dissolved into NMP relative to the total weight of aramid resin is calculated according to the following formula (8). The content of the component dissolved into NMP relative to the total weight of the aramid resin [wt%] = Area value of the aramid impregnation solution / Area value of the reference solution × 100 (8) [Increase in breathability] According to JIS P8117, the air permeability of polyethylene porous membranes and laminated diaphragms cut into 60mm × 60mm dimensions was measured using an EGO1 digital permeability testing machine manufactured by Asahi Seiko Co., Ltd. The air permeability of the polyethylene porous membrane was subtracted from the air permeability of the laminated diaphragm, and the resulting value was taken as the increase in air permeability accompanying the stacking of porous layers.

[0150] [Shape retention rate after heating at 150℃] The laminated diaphragms obtained in the examples and comparative examples described later were cut into 8cm × 8cm squares. On the inner side of the 8cm square outer edge of the cut laminated diaphragm, 6cm square lines were drawn in both the MD and TD directions to obtain a sample for heat resistance testing. The sample was sandwiched in paper and placed in an oven heated to 150°C. After 1 hour, the sample was removed from the oven, and the lengths of the leads in the MD and TD directions were measured using digital calipers. The measured length D of the lead in the MD direction was used as the basis for the heat resistance test.MD [cm] and the length D of the lead wire in the TD direction TD [cm], the “150℃ MD shape retention rate” and “150℃ TD shape retention rate” of the laminated diaphragm are calculated by the following formulas (9) and (10). 150℃ MD shape retention rate [%) = D MD / 6×100···(9) 150℃ TD shape retention rate [%) = D TD / 6×100···(10) The smaller of the 150°C MD shape retention rate [%) and the 150°C TD shape retention rate [%) is used as the 150°C shape retention rate [%) of the laminated diaphragm.

[0151] [Weight per unit area] Cut out an 8cm × 8cm square sample from the porous membrane. Measure the weight of this sample, denoted as W1[g]. Calculate the weight per unit area of ​​the porous membrane according to the following formula (11). Weight per unit area of ​​porous membrane [g / m³] 2 ]=W1[g] / (0.08×0.08)···(11) Cut out an 8cm × 8cm square sample from the laminated diaphragm. Measure the weight of this sample and denote it as W2[g]. Calculate the weight per unit area of ​​the laminated diaphragm according to the following formula (12). Weight per unit area of ​​laminated diaphragms [g / m²] 2 ]=W2[g] / (0.08×0.08)···(12) The unit area weight of the porous layer is calculated by subtracting the unit area weight of the porous membrane from the unit area weight of the laminated membrane.

[0152] [Manufacturing Example 1] The coating solution (1) is prepared by the following steps. The aramid resin contained in the coating solution (1) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 450 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.76 g of 4,4'-diaminodiphenyl sulfone (DDS) and allow it to dissolve completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 115.67 g of terephthaloyl chloride (TPC) in three portions. React for 1 hour to synthesize block A1 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.002. 5. Add 61.74 g of p-phenylenediamine (PPD) to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 113.08g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B1, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A1. At this point, the molar ratio of PPD to TPC was 1.025. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (A) is obtained. In the block copolymer contained in the aramid polymerization solution (A), block A1 accounts for 50% of the total molecules, and block B1 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (A), alumina (average particle size: 13 nm) is added and mixed. At this time, alumina is added so that the weight ratio of aramid resin to alumina is 3:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (1).

[0153] [Manufacturing Example 2] Except for changing the weight ratio of aramid resin to alumina in step 8 to 4:1, the same operation as in manufacturing example 1 was performed to prepare a paste-like coating liquid (2).

[0154] [Manufacturing Example 3] The coating solution (3) is prepared by the following steps. The aramid resin contained in the coating solution (3) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 450 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.61 g of DDS and dissolve it completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 116.13 g of TPC in three portions. React for 1 hour to synthesize block A2 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 0.997. 5. Add 61.67g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 112.96g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B2, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A2. At this point, the molar ratio of PPD to TPC was 1.025. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, aramid polymerization solution (B) is obtained. In the block copolymer contained in aramid polymerization solution (B), block A2 accounts for 50% of the total molecules, and block B2 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (B), alumina (average particle size: 13 nm) is added and mixed. At this time, alumina is added so that the weight ratio of aramid resin to alumina is 2:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (3).

[0155] [Manufacturing Example 4] Except for changing the weight ratio of aramid resin to alumina in step 8 to 3:1, the same operation as in manufacturing example 3 was performed to prepare a paste-like coating liquid (4).

[0156] [Manufacturing Example 5] The coating solution (5) is prepared by the following steps. The aramid resin contained in the coating solution (5) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 450 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.70 g of DDS and dissolve it completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 115.86 g of TPC in three portions. React for 1 hour to synthesize block A3 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.00. 5. Add 61.71g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 113.03g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B3, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A3. At this point, the molar ratio of PPD to TPC was 1.025. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (C) is obtained. In the block copolymer contained in the aramid polymerization solution (C), block A3 accounts for 50% of the total molecules, and block B3 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (C), alumina (average particle size: 13 nm) is added and mixed. At this time, alumina is added so that the weight ratio of aramid resin to alumina is 3:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (5).

[0157] [Manufacturing Example 6] Except for changing the weight ratio of aramid resin to alumina in step 8 to 4:1, the same operation as in manufacturing example 5 was performed to prepare a paste-like coating liquid (6).

[0158] [Manufacturing Example 7] The coating solution (7) is prepared by the following steps. The aramid resin contained in the coating solution (7) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4234 g of NMP to the flask. Further, add 325.5 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 450 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 94.01 g of DDS and allow it to dissolve completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 77.25g of TPC in three portions. React for 1 hour to synthesize block A4 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 0.995. 5. Add 95.53g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 173.29g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B4, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A4. At this point, the molar ratio of PPD to TPC was 1.035. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2°C. In this way, an aramid polymerization solution (D) is obtained. In the block copolymer contained in the aramid polymerization solution (D), block A4 accounts for 30% of the total molecules, and block B4 accounts for 70% of the remaining total molecules. The aramid polymerization solution (D) contains an aramid resin containing the block copolymer. 8. In the aramid polymerization solution (D), alumina (average particle size: 13 nm) is added and mixed. At this time, alumina is added so that the weight ratio of the aramid resin containing the block copolymer to alumina is 1:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (7).

[0159] [Comparative Manufacturing Example 1] The coating solution (8) is prepared by the following steps. The aramid resin contained in the coating solution (8) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 800 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.70 g of DDS and dissolve it completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 116.30 g of TPC in three portions. React for 1 hour to synthesize block A5 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 0.995. 5. Add 61.71g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 113.03g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B5, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A5. At this point, the molar ratio of PPD to TPC was 1.025. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (E) is obtained. In the block copolymer contained in the aramid polymerization solution (E), block A5 accounts for 50% of the total molecules, and block B5 accounts for the remaining 50% of the total molecules. 8. Alumina (average particle size: 13 nm) is added to the aramid polymerization solution (E) and mixed. At this time, alumina is added so that the weight ratio of aramid resin to alumina is 3:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (8).

[0160] [Comparative Manufacturing Example 2] The coating solution (9) is prepared by the following steps. The aramid resin contained in the coating solution (9) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4202 g of NMP to the flask. Further, add 365.9 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (8.0 wt%). Add water to the calcium chloride solution to achieve a water content of 300 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.97g of DDS and dissolve it completely. 4. Cool the polymerization system to 16°C. While maintaining the polymerization system at 16±2°C, add a total of 114.25 g of TPC in three portions. React for 1 hour to synthesize block A6 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.016. 5. Add 61.83g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 18±2℃, a total of 114.03g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B6, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A6. At this point, the molar ratio of PPD to TPC was 1.018. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (F) is obtained. In the block copolymer contained in the aramid polymerization solution (F), block A6 accounts for 50% of the total molecules, and block B6 accounts for the remaining 50% of the total molecules. 8. Alumina (average particle size: 13 nm) is added to the aramid polymerization solution (F) and mixed. At this time, alumina is added so that the weight ratio of aramid resin to alumina is 1:1. 9. In the mixture obtained in step 8, NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 4% by weight. The "solid content" mentioned here refers to the content of aramid resin and alumina. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare a slurry coating solution (9).

[0161] [Comparative Manufacturing Example 3] Except for changing the weight ratio of aramid resin to alumina to 3:2 in step 8, the same operation as in comparative manufacturing example 1 was performed to prepare a paste-like coating liquid (10).

[0162] [Comparative Manufacturing Example 4] Except for changing the weight ratio of aramid resin to alumina to 7:3 in step 8, the same operation as in comparative manufacturing example 1 was performed to prepare a paste-like coating liquid (11).

[0163] [Comparative Manufacturing Example 5] Except for changing the weight ratio of aramid resin to alumina to 4:1 in step 8, the same operation as in comparative manufacturing example 1 was performed to prepare a paste-like coating liquid (12).

[0164] [Manufacturing Example 8] The coating solution (13) is prepared by the following steps. The aramid resin contained in the coating solution (13) is a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 410 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.23g of DDS and dissolve it completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 115.48 g of TPC in three portions. React for 1 hour to synthesize block A7 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.00. 5. Add 61.53g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 114.63g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B7, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A7. At this point, the molar ratio of PPD to TPC was 1.008. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (G) is obtained. In the block copolymer contained in the aramid polymerization solution (G), block A7 accounts for 50% of the total molecules, and block B7 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (G), NMP was added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 3% by weight. The "solid content" mentioned here refers to the content of aramid resin. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare the coating solution (13).

[0165] [Manufacturing Example 9] The coating solution (14) is prepared by the following steps. The aramid resin contained in the coating solution (14) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 360 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.62 g of DDS and allow it to dissolve completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 115.40 g of TPC in three portions. React for 1 hour to synthesize block A8 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.003. 5. Add 61.90g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 114.00g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B8, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A8. At this point, the molar ratio of PPD to TPC was 1.019. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, an aramid polymerization solution (H) is obtained. In the block copolymer contained in the aramid polymerization solution (H), block A8 accounts for 50% of the total molecules, and block B8 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (H), NMP was added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 3% by weight. The "solid content" mentioned here refers to the content of aramid resin. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare the coating solution (14).

[0166] [Manufacturing Example 10] The coating solution (15) is prepared by the following steps. The aramid resin contained in the coating solution (15) comprises a block copolymer having poly(4,4'-diphenylsulfonyl terephthalamide) blocks. 1. Thoroughly dry a 5L separable flask equipped with stirring blades, a thermometer, a nitrogen inlet pipe, and a powder inlet. 2. Add 4241 g of NMP to the flask. Further, add 326.1 g of calcium chloride to the flask and heat to 100°C. Dissolve the calcium chloride completely to obtain a calcium chloride solution (7.14 wt%). Add water to the calcium chloride solution to achieve a water content of 150 ppm. It should be noted that the calcium chloride used was pre-dried under vacuum at 200°C for 2 hours. 3. While maintaining the polymerization system at 40°C, add 141.04 g of DDS and dissolve it completely. 4. Cool the polymerization system to 25°C. While maintaining the polymerization system at 25±2°C, add a total of 115.23 g of TPC in three portions. React for 1 hour to synthesize block A9 composed of poly(4,4'-diphenylsulfonyl terephthalamide). At this point, the molar ratio of DDS to TPC is 1.001. 5. Add 61.50g of PPD to the flask and dissolve it completely within 1 hour. 6. While maintaining the polymerization system at 25±2℃, a total of 113.86g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, causing block B9, composed of poly(p-phenylene terephthalamide), to elongate on both sides of block A9. At this point, the molar ratio of PPD to TPC was 1.014. 7. The polymerization system is aged for 1 hour while maintaining the temperature at 20±2℃. In this way, aramid polymerization solution (I) is obtained. In the block copolymer contained in aramid polymerization solution (I), block A9 accounts for 50% of the total molecules, and block B9 accounts for the remaining 50% of the total molecules. 8. In the aramid polymerization solution (I), NMP is added as a diluent and calcium carbonate as a neutralizing agent to make the solid content 3% by weight. The "solid content" mentioned here refers to the content of aramid resin. The solution is stirred for 20 minutes to dilute and neutralize it. The neutralized solution is degassed under reduced pressure to prepare the coating solution (15).

[0167] [Example 1] While conveying a porous membrane (polyethylene porous membrane, membrane thickness: 9μm, unit area weight: 5g / m³), the following steps are taken: 2 While coating one side (surface) of the porous membrane with the slurry-like coating liquid (1) prepared in Manufacturing Example 1, a coated membrane is formed on one side of the porous membrane. Then, while conveying the porous membrane with the coated membrane formed thereon, the coated membrane and the porous membrane are passed through a precipitation tank set at 50°C and 70% relative humidity, exposing the coated membrane to air containing water vapor at 50°C and 70% relative humidity. As a result, a block copolymer is precipitated on one side (surface) of the porous membrane to form a coating layer. Next, calcium chloride and solvent are removed from the coating layer by washing the laminate consisting of the porous membrane and the coating layer precipitated on one side of the porous membrane with water. Then, by drying the laminate, a laminated diaphragm (1) with a porous layer formed on one side of the porous membrane is obtained.

[0168] [Example 2] Except that the slurry coating liquid (2) prepared in Manufacturing Example 2 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (2).

[0169] [Example 3] Except that the slurry coating liquid (3) prepared in Manufacturing Example 3 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (3).

[0170] [Example 4] Except that the slurry coating liquid (4) prepared in Manufacturing Example 4 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (4).

[0171] [Example 5] Except that the slurry coating liquid (5) prepared in Manufacturing Example 5 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (5).

[0172] [Example 6] Except that the slurry coating liquid (6) prepared in Manufacturing Example 6 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (6).

[0173] [Example 7] Except that the slurry coating liquid (7) prepared in Manufacturing Example 7 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (7).

[0174] [Comparative Example 1] Except that the slurry coating liquid (8) prepared in Comparative Manufacturing Example 1 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (8).

[0175] [Comparative Example 2] Except that the slurry coating liquid (9) prepared in Comparative Manufacturing Example 2 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (9).

[0176] [Comparative Example 3] Except that the paste-like coating liquid (10) prepared in Comparative Manufacturing Example 3 was used instead of the paste-like coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (10).

[0177] [Comparative Example 4] Except that the slurry coating liquid (11) prepared in Comparative Manufacturing Example 4 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (11).

[0178] [Comparative Example 5] Except that the slurry coating liquid (12) prepared in Comparative Manufacturing Example 5 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (12).

[0179] [Example 8] Except that the coating liquid (13) prepared in Manufacturing Example 8 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (13).

[0180] [Example 9] Except that the coating liquid (14) prepared in Manufacturing Example 9 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (14).

[0181] [Example 10] Except that the coating liquid (10) prepared in Manufacturing Example 10 was used instead of the slurry coating liquid (1), the same operation as in Example 1 was performed to obtain the laminated diaphragm (15).

[0182] [result] The composition and measurement results of Examples 1-10 and Comparative Examples 1-5 are shown in Table 1 below. In Table 1, "-(0%)" means that the coating solution used does not contain aluminum oxide.

[0183] [Table 1]

[0184] As shown in Table 1, the laminated diaphragms (1) to (7) and (13) to (15) of Examples 1 to 10 were obtained using compositions in which the content of the component dissolved into NMP was greater than 25.0% by weight and less than 45.0% by weight. In contrast, the laminated diaphragm (8) of Comparative Example 1 was obtained using the composition in which the content was greater than 45.0% by weight, and the laminated diaphragms (9) to (12) of Comparative Examples 2 to 5 were obtained using the composition in which the content was less than 25.0% by weight. Compared with the laminated diaphragms (8), (9), (10), and (12) of Comparative Examples 1, 2, 3, and 5, the laminated diaphragms (1) to (7) and (13) to (15) of Examples 1 to 10 had a higher heat-induced shape retention rate. In addition, compared with the laminated diaphragms (11) and (12) of Comparative Examples 4 and 5, the increase in air permeability of the laminated diaphragms (1) to (7) and (13) to (15) of Examples 1 to 10 is low. [Industry availability]

[0185] One aspect of this invention can be used in the manufacture of non-aqueous electrolyte secondary batteries.

Claims

1. A composition for forming a laminated separator for a non-aqueous electrolyte secondary battery, characterized in that, Resins containing amide bonds, The resin having amide bonds contains components dissolved into N-methyl-2-pyrrolidone. The content of the component dissolved into N-methyl-2-pyrrolidone is greater than 25.0% by weight and less than 45.0% by weight relative to the total weight of the resin having amide bonds.

2. The composition according to claim 1, wherein, The resin is an aramid resin.

3. The composition according to claim 2, wherein, The aramid resin comprises a block copolymer. The block copolymer has: Block A, whose main components are the units represented by the following equation (1), -(NH-Ar 1 -NHCO-Ar 2 -CO)- Equation (1), and Block B, whose main component is a unit represented by the following equation (2), -(NH-Ar 3 -NHCO-Ar 4 -CO)-Formula (2), In equations (1) and (2), Ar 1 Ar 2 Ar 3 and Ar 4 Whether the same or different in each unit, Ar 1 Ar 2 Ar 3 and Ar 4 Each is independently a divalent group having one or more aromatic rings. All Ar 1 More than 50% of them have a structure in which two aromatic rings are linked by sulfonyl bonds. All Ar 3 Less than 50% of them have a structure with two aromatic rings linked by sulfonyl bonds. All Ar 1 and Ar 3 10-70% of them have a structure in which two aromatic rings are linked by sulfonyl bonds.

4. The composition according to claim 1, wherein, The composition further comprises filler. The content of the filler is 20-90% by weight relative to the total amount of the resin and the filler.

5. A layer for forming a laminated separator for a non-aqueous electrolyte secondary battery, characterized in that, It comprises the composition of claim 1.

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

7. A laminated separator for a non-aqueous electrolyte secondary battery, characterized in that, A layer for forming a laminated separator for a non-aqueous electrolyte secondary battery, as described in claim 5, is stacked on one or both sides of a polyolefin porous membrane.

8. The laminated separator for a non-aqueous electrolyte secondary battery according to claim 7, wherein, In addition to the polyolefin porous membrane and the layer for forming the laminated separator for the non-aqueous electrolyte secondary battery, the laminated separator also includes an adhesive layer.

9. A component for a non-aqueous electrolyte secondary battery, characterized in that, The battery is configured with a positive electrode, a laminated separator for a non-aqueous electrolyte secondary battery as described in claim 7 or 8, and a negative electrode in sequence.

10. A non-aqueous electrolyte secondary battery, characterized in that, It includes the laminated separator for a non-aqueous electrolyte secondary battery as described in claim 7 or 8.

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