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A lithium ion battery separator with heat resistance and high mechanical strength and preparation method thereof

A lithium-ion battery, mechanical strength technology, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of sharp drop in strength, large thermal shrinkage, fire or explosion, etc., to improve safety and improve resistance. Thermal performance, the effect of preventing fire and explosion

Active Publication Date: 2022-07-22
SINOMA LITHIUM BATTERY SEPARATOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Conventional lithium-ion battery separators are polyolefin separators, which have the problems of poor thermal stability, large thermal shrinkage rate, and a sharp drop in strength after shrinkage, which can easily cause a short circuit between the positive and negative electrodes of the lithium-ion battery, resulting in thermal runaway, resulting in fire or explosion

Method used

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  • A lithium ion battery separator with heat resistance and high mechanical strength and preparation method thereof
  • A lithium ion battery separator with heat resistance and high mechanical strength and preparation method thereof
  • A lithium ion battery separator with heat resistance and high mechanical strength and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0039] Add 0.26kg of sodium carboxymethyl cellulose into 7.5kg of deionized water, mix and stir to obtain slurry A; add 20kg of boehmite with a D50 of 0.5 μm and 0.1kg of dispersant into 32kg of water, mix and stir to obtain slurry B; A , B two kinds of slurries are mixed and prepared into slurry C by high-speed dispersion or ball milling; 3kg of binder and 0.04kg of wetting agent are added to slurry C to prepare a coating slurry; microgravure coating is used to coat the above The slurry was coated on both sides of the 9 μm base film, and after drying, a power lithium-ion battery separator was obtained. The thickness of the single-layer coating is 2 μm, accounting for 30.77% of the thickness of the separator; the inorganic filler boehmite in the coating accounts for 92.19%, and the binder polyacrylic resin accounts for 6.22%.

Embodiment 2

[0041]Add 0.16kg of sodium carboxymethylcellulose into 4.6kg of deionized water, mix and stir to obtain slurry A; add 20kg of boehmite with a D50 of 0.8 μm and 0.08kg of dispersant into 35kg of water, mix and stir to obtain slurry B; A , B two kinds of slurry are mixed and prepared into slurry C by high-speed dispersion or ball milling; 3kg binder and 0.04kg wetting agent are added to slurry C to prepare a coating slurry; the above slurry is coated on The surface of one side of the 9μm base film was dried to obtain a power lithium-ion battery separator. The thickness of the coating is 3 μm, accounting for 25% of the thickness of the separator; the inorganic filler boehmite in the coating accounts for 92.65%, and the binder polyacrylic resin accounts for 6.25%.

Embodiment 3

[0043] Add 0.26kg of sodium carboxymethylcellulose to 7.5kg of deionized water, mix and stir to obtain slurry A; add 20kg of alumina with a D50 of 0.8 μm to 32kg of water, mix and stir to obtain slurry B; two kinds of slurry A and B After the material is mixed, it is prepared into slurry C by high-speed dispersion or ball milling; 2.5kg of binder and 0.03kg of wetting agent are added to slurry C to prepare a coating slurry; the above slurry is coated by microgravure coating On the surface of one side of the 9 μm base film, a power lithium-ion battery separator was obtained after drying. The thickness of the single-layer coating is 2 μm, accounting for 18% of the thickness of the diaphragm; the inorganic filler alumina in the coating accounts for 93.39%, and the binder polyacrylic resin accounts for 5.25%.

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Abstract

The invention proposes a lithium-ion battery separator with heat resistance and high mechanical strength, which includes a polyolefin porous base material, a porous heat-resistant layer coated on one side surface or both sides of the base material, and a polyolefin porous base material. The porosity of the material is 20% to 60%, the needle punch strength is ≥200gf, and the peel strength of the porous heat-resistant layer is ≥10N / m; the porous heat-resistant layer includes inorganic fillers, binders, thickeners, dispersants and wetting agents. agent, wherein the mass of the inorganic filler accounts for more than 90% of the mass of the porous heat-resistant layer, and the mass of the binder accounts for 4% to 7% of the mass of the porous heat-resistant layer. The present invention improves the heat resistance of the separator by coating at least one side surface of the polyolefin porous base material with a porous heat-resistant layer, effectively improves the safety of the lithium-ion battery, prevents fire and explosion caused by thermal shock, and solves the problem of thermal shock. The problem is that the shrinkage rate is large and the strength drops significantly after heating.

Description

Technical field [0001] The invention belongs to the technical field of lithium-ion battery separators, and in particular is a lithium-ion battery separator with heat resistance and high mechanical strength and a preparation method thereof. Background technique [0002] As the energy density of lithium-ion batteries continues to increase, the safety performance requirements of separators continue to increase. Conventional lithium-ion battery separators are polyolefin separators, which have problems with poor thermal stability, large thermal shrinkage, and a significant decrease in strength after shrinkage. This can easily cause short circuits between the positive and negative electrodes of the lithium-ion battery, resulting in thermal runaway, leading to fire or explosion. Contents of the invention [0003] The technical problem solved by the present invention is to provide a lithium ion battery separator with heat resistance and high mechanical strength. By coating a porou...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M50/44H01M50/449H01M50/434H01M50/411H01M50/403H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 高飞飞白耀宗陈淳刘杲珺白麟王连广孙婧高坡李子阳秦文娟
Owner SINOMA LITHIUM BATTERY SEPARATOR CO LTD