Modified composite separator and method for manufacturing the same

Abstract

The present invention relates to the technical field of battery separators, and provides a coated modified composite separator, a manufacturing method thereof, and a coating slurry for manufacturing the composite separator. The coated modified composite separator includes a base membrane and a coating, in which the coating covers either one or both sides of the base membrane, and the coating includes at least two of the following: b2.1 high temperature resistant polymer microspheres, b2.2 high temperature resistant polymer nanofibers, and b2.3 inorganic particles. The coating in the modified composite separator of the present invention significantly increases the thermal dimensional stability of the base membrane, reduces the areal density of the composite separator, increases the energy density of the battery, reduces the probability of thermal runaway, and improves the safety of the battery.

Claims

[Claim 1] The coated modified composite separator comprises a base film and a coating. The coating covers one or both sides of the base film. The coating is: b2.1 high temperature resistant polymer microspheres, b2.2 High-temperature resistant polymer nanofibers, and b2.3 Inorganic particles A coated modified composite separator characterized by containing [a certain substance]. [Claim 2] The coated modified composite separator according to claim 1, characterized in that the high-temperature resistant polymer contains polyimide. [Claim 3] The particle size of the high-temperature resistant polymer microspheres is 3 to 5000 nm, and / or The diameter of the high-temperature resistant polymer nanofibers is 5 to 1500 nm; and / or The length of the high-temperature resistant polymer nanofibers is 0.5 to 1000 μm; and / or The average particle size of the inorganic particles is 3 nm to 5 μm; and / or The thickness of the base film is 1.5 to 40 μm; and / or, The total thickness of the coated modified composite separator is 2.0 to 45 μm; and / or The coated modified composite separator according to claim 1, characterized in that the coating thickness is 0.2 to 10 μm. [Claim 4] The base film is a polymer-based film, or a polymer-based film coated with inorganic particles. The coated modified composite separator according to claim 1, characterized in that the polymer base film comprises at least one of a polyolefin-based film, a cellulose-based film, a polyester-based film, an aramid fiber-based film, a polyimide-based film, and an organic-inorganic hybrid-based film. [Claim 5] The coated modified composite separator according to claim 4, characterized in that the polymer base film comprises a single layer film, a double layer film, or a multilayer film, and the polymer base films contained in each layer are the same or different. [Claim 6] The high-temperature resistant polymer microspheres include at least one of the following: unmodified high-temperature resistant polymer microspheres, surface-modified high-temperature resistant polymer microspheres, and inorganic hybrid high-temperature resistant polymer microspheres. The polymers in the unmodified high-temperature resistant polymer microspheres, surface-modified high-temperature resistant polymer microspheres, and inorganic hybrid high-temperature resistant polymer microspheres include at least one of P84, polyetherimide, polyphosphazene, polyacrylonitrile, polystyrene, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyvinylidene fluoride-hexafluoropropylene, polymethyl methacrylate, polytetrafluoroethylene, polyimide, polyester, cellulose, polyetheretherketone, polyarylether, polyamide, and polybenzimidazole. The surface-modified high-temperature resistant polymer microspheres include at least one of the following: inorganic surface-modified high-temperature resistant polymer microspheres, high-temperature resistant polymer microspheres having polar groups after surface treatment, or high-temperature resistant polymer microspheres surface-coated with a functionalized polymer layer containing polar groups. The coated modified composite separator according to claim 1, characterized in that the inorganic hybrid high-temperature resistant polymer microspheres include at least one of polyimide / silica microspheres, polyimide / titanium dioxide microspheres, polyimide / zirconia microspheres, polyimide / zinc oxide microspheres, polyimide / magnesium oxide microspheres, polyimide / magnesium hydroxide microspheres, polyimide / alumina microspheres, polyimide / boehmite microspheres, polyimide / cerium oxide microspheres, polyimide / scandium oxide microspheres, and polyimide / vanadium pentoxide microspheres. [Claim 7] The high-temperature resistant polymer nanofibers include at least one of the following: unmodified high-temperature resistant polymer nanofibers, surface-modified high-temperature resistant polymer nanofibers, and inorganic hybrid high-temperature resistant polymer nanofibers. Unmodified high-temperature resistant polymer nanofibers, and high-temperature resistant polymer nanofibers used for surface modification and inorganic hybridization, include at least one of P84 nanofibers, polyetherimide nanofibers, polyvinylidene fluoride and its copolymer nanofibers, polyvinylidene fluoride-hexafluoropropylene nanofibers, polytetrafluoroethylene nanofibers, polyphosphazene nanofibers, polyacrylonitrile nanofibers, polyimide nanofibers, polyester nanofibers, cellulose nanofibers, polyetheretherketone nanofibers, polyarylether nanofibers, polyamide nanofibers, and polybenzimidazole nanofibers. The coated modified composite separator according to claim 1, wherein the surface-modified high-temperature resistant polymer nanofiber comprises at least one of inorganic surface-modified high-temperature resistant polymer nanofibers, high-temperature resistant polymer nanofibers having polar groups after surface treatment, or high-temperature resistant polymer nanofibers surface-coated with a functionalized polymer layer containing polar groups. [Claim 8] The inorganic particles in the coating include at least one of ceramics, metal oxides, metal hydroxides, metal carbonates, silicates, kaolin, talc, minerals, and glass; The coated modified composite separator according to claim 1, characterized in that the average particle size of the inorganic particles is 10 nm to 5 μm. [Claim 9] The coating further comprises at least one of a binder, a surfactant, a dispersant, a wetting agent, and an antifoaming agent. The amount of binder is 0.3 to 10.5 parts by weight; and / or The amount of surfactant is 0.05 to 7 parts by weight; and / or The amount of dispersant is 0.05 to 9 parts by weight; and / or The amount of wetting agent is 0.02 to 7 parts by weight; and / or The coated modified composite separator according to claim 1, wherein the amount of the defoaming agent is 0.04 to 4 parts by weight. [Claim 10] The following steps: (1) b2.1 High temperature resistant polymer microspheres, b2.2 High-temperature resistant polymer nanofibers, and b2.3 Inorganic particles To formulate a coating slurry containing; (2) Apply the coating slurry to either one or both sides of the base film. A method for producing a coated modified composite separator according to claim 1, characterized by including the following: [Claim 11] The coating slurry further contains a slurry solvent, and the slurry solvent is either an aqueous solvent or an organic solvent. The aqueous solvent comprises pure water, or a mixed solution of pure water with at least one of ethanol, ethylene glycol, glycerol, isopropyl alcohol, propylene glycol, butanol, and acetic acid; The method for producing the product according to claim 10, wherein the organic solvent comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetone, ethanol, isopropanol, ethylene carbonate, and dimethyl carbonate. [Claim 12] The manufacturing method according to claim 10, characterized in that the coating method includes at least one of electrostatic spraying, blade coating, rotary spraying, extrusion coating, transfer coating, dip coating, wire rod coating, gravure, or microgravure coating. [Claim 13] The coating slurry further contains an additive selected from at least one of the following: a binder, a surfactant, a dispersant, a wetting agent, and an antifoaming agent. The amount of slurry solvent is 100 to 5000 parts by weight; and / or The amount of binder is 0.5 to 12.5 parts by weight; and / or The amount of surfactant is 0.1 to 5 parts by weight; and / or The amount of dispersant is 0.1 to 7 parts by weight; and / or The amount of wetting agent is 0.05 to 5 parts by weight; and / or The manufacturing method according to claim 10, wherein the amount of the defoaming agent is 0.1 to 4 parts by weight. [Claim 14] Slurry solvent, b2.1 high temperature resistant polymer microspheres, b2.2 High-temperature resistant polymer nanofibers, and b2.3 Inorganic particles A coating slurry containing [the specified ingredient]. [Claim 15] The coating slurry according to claim 14, characterized in that the coating slurry contains high temperature resistant polymer nanofibers, inorganic particles, and a slurry solvent, and the coating slurry contains 0.4 to 65 parts by weight of high temperature resistant polymer nanofibers and 35 to 99.6 parts by weight of inorganic particles, and the total parts by weight of the high temperature resistant polymer nanofibers and inorganic particles is 100. [Claim 16] The coating slurry according to claim 14, characterized in that the coating slurry contains high-temperature resistant polymer microspheres, inorganic particles, and a slurry solvent, and the weight ratio of high-temperature resistant polymer microspheres to inorganic particles is 0.1 to 99.9:99.9 to 0.

1. [Claim 17] The coating slurry according to claim 14, characterized in that the coating slurry contains high temperature resistant polymer nanofibers, high temperature resistant polymer microspheres, and a slurry solvent, wherein the high temperature resistant polymer is polyimide, and the parts by weight of each component of the coating slurry are 1 to 3 parts binder, 89 to 52 parts solvent, and 10 to 45 parts polyimide. [Claim 18] The solid content of the coating slurry is 2 to 50 wt%; and / or The coating slurry according to claim 14, wherein the viscosity of the coating slurry is 50 to 4000 cP. [Claim 19] The slurry solvent is either an aqueous solvent or an organic solvent. The aqueous solvent comprises pure water, or a mixed solution of water and at least one of ethanol, ethylene glycol, glycerol, isopropyl alcohol, and butanol; The coating slurry according to claim 14, wherein the organic solvent comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetone, ethanol, isopropanol, ethylene carbonate, and dimethyl carbonate. [Claim 20] The coating slurry further comprises an additive selected from at least one of a binder, a surfactant, a dispersant, a wetting agent, and an antifoaming agent. The amount of slurry solvent is 100 to 5000 parts by weight; and / or The amount of binder is 0.5 to 12.5 parts by weight; and / or The amount of surfactant is 0.1 to 5 parts by weight; and / or The amount of dispersant is 0.1 to 7 parts by weight; and / or The amount of wetting agent is 0.05 to 5 parts by weight; and / or The coating slurry according to claim 14, wherein the amount of the defoaming agent is 0.1 to 4 parts by weight. [Claim 21] A lithium-ion battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is a coated modified composite separator as described in claim 1, or a coated modified composite separator manufactured by the method described in claim 10.

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