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Lithium ion battery membrane with heat resistance and high mechanical strength and preparation method thereof

A lithium-ion battery, mechanical strength technology, applied in the direction of secondary batteries, battery pack parts, circuits, etc., can solve the problems of sharp drop in strength, large thermal shrinkage, fire or explosion, etc., to solve the problem of large thermal shrinkage, Improves heat resistance and prevents fire and explosion

Active Publication Date: 2021-04-09
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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  • Lithium ion battery membrane with heat resistance and high mechanical strength and preparation method thereof
  • Lithium ion battery membrane with heat resistance and high mechanical strength and preparation method thereof
  • Lithium ion battery membrane with heat resistance and high mechanical strength and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Add 0.26kg of sodium carboxymethyl cellulose to 7.5kg of deionized water, mix and stir evenly to obtain slurry A; add 20kg of boehmite with a D50 of 0.5μm and 0.1kg of dispersant to 32kg of water, mix and stir evenly to obtain slurry B; A After the two kinds of slurries, B and B are mixed, the slurry C is prepared by high-speed dispersion or ball milling; 3kg of binder and 0.04kg of wetting agent are added to the slurry C to prepare a coating slurry; the above-mentioned The slurry is coated on both sides of the 9 μm base film, and after drying, a power lithium-ion battery separator is 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 carboxymethyl cellulose to 4.6kg of deionized water, mix and stir evenly to obtain slurry A; add 20kg of boehmite with D50 of 0.8μm and 0.08kg of dispersant to 35kg of water, mix and stir evenly to obtain slurry B; A After the two kinds of slurries of B and B are mixed, slurry C is prepared by high-speed dispersion or ball milling; 3kg of binder and 0.04kg of wetting agent are added in slurry C to prepare coating slurry; the above-mentioned slurry is coated on The surface of one side of the 9μm base film is 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 diaphragm; 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 sodium carboxymethyl cellulose to 7.5kg deionized water, mix and stir evenly to obtain slurry A; add 20kg of alumina with a D50 of 0.8μm to 32kg water, mix and stir evenly to obtain slurry B; two kinds of slurry A and B After the materials are mixed, the slurry C is prepared by high-speed dispersion or ball milling; 2.5kg of binder and 0.03kg of wetting agent are added to the slurry C to prepare a coating slurry; the above slurry is coated by micro-gravure coating On the surface of one side of the 9μm base film, after drying, a power lithium-ion battery separator is obtained. 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 provides a lithium ion battery membrane with heat resistance and high mechanical strength. The lithium ion battery membrane comprises a polyolefin porous base material and a porous heat-resistant layer coated on one side surface or two side surfaces of the base material, wherein the porosity of the polyolefin porous base material is 20-60%, the needling strength is greater than or equal to 200 gf, and the peel strength of the porous heat-resistant layer is greater than or equal to 10 N / m; and the porous heat-resistant layer comprises inorganic filler, a binder, a thickening agent, a dispersing agent and a wetting agent, the mass of the inorganic filler accounts for 90% or above of the mass of the porous heat-resistant layer, and the mass of the binder accounts for 4%-7% of the mass of the porous heat-resistant layer. The porous heat-resistant layer is coated on the surface of at least one side of the polyolefin porous base material, so that the heat resistance of the diaphragm is improved, the safety of the lithium ion battery is effectively improved, the phenomena of fire explosion and the like caused by thermal shock are prevented, and the problems that the thermal shrinkage rate is high and the strength is greatly reduced after heating are solved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery separators, in particular to a lithium-ion battery separator with heat resistance and high mechanical strength and a preparation method thereof. Background technique [0002] With the continuous improvement of the energy density of lithium-ion batteries, the safety performance requirements of the separator continue to increase. Conventional lithium-ion battery separators are polyolefin separators, which have 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, leading to fire or explosion. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a lithium-ion battery separator with heat resistance and high mechanical strength, and to i...

Claims

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Application Information

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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
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