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Battery diaphragm, preparation method thereof, lithium ion battery and electric vehicle

A battery diaphragm and base film technology, which is applied in the direction of secondary batteries, battery components, circuits, etc., can solve the problems of uneven distribution of pore structure, poor thermal shrinkage resistance of the diaphragm, and low surface porosity of the battery diaphragm, and achieve Low shrinkage, prevent short circuit of positive and negative electrodes of battery, and improve strength

Active Publication Date: 2020-01-07
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the defects of low surface porosity, uneven distribution of pore structure, and poor thermal shrinkage resistance of the separator in the prior art, the present invention provides a battery separator, which includes a polymer fiber layer, Wherein, the polymer fiber layer contains polymer fibers, and the polymer fibers contain cross-linked polymers, and the cross-linked polymers are made of modified polyethylene terephthalate and acrylic polymers. cross-linked;

Method used

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  • Battery diaphragm, preparation method thereof, lithium ion battery and electric vehicle
  • Battery diaphragm, preparation method thereof, lithium ion battery and electric vehicle

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preparation example Construction

[0044] In a second aspect, the present invention also provides a method for preparing a battery separator, wherein the method includes the following steps:

[0045] (1) carry out surface modification to polyethylene terephthalate, make it contain hydroxyl group and / or carboxyl group, or make it have carbon-carbon double bond, obtain modified polyethylene terephthalate;

[0046] (2) The modified polyethylene terephthalate is mixed with an acrylic polymer for melt spinning to form a polymer fiber layer.

[0047] According to the present invention, the above method for modifying polyethylene terephthalate has been fully introduced, and will not be repeated here in order to avoid unnecessary repetition.

[0048] Wherein, in step (1), the weight ratio of the silane coupling agent to polyethylene terephthalate is 0.05:1-0.5:1, and the silane coupling agent and polyethylene terephthalate The weight ratio of the alcohol ester is controlled in the above range, and the modified polyeth...

Embodiment 1

[0083] Prepare battery separators as follows:

[0084](1) First use N,N-dimethylformamide solution of 0.1mol / L silane coupling agent 3-acryloyloxypropyltrimethoxysilane to polyethylene terephthalate at 60°C After 2 hours of treatment, modified polyethylene terephthalate was obtained. The amount of the silane coupling agent is such that the hydroxyl content and carboxyl content on the surface of polyethylene terephthalate are shown in Table 2.

[0085] (2) Mix the modified polyethylene terephthalate prepared in step (1) with butyl acrylate-hydroxyethyl acrylate copolymer to obtain a polymer fiber layer composition. Among them, the content of modified polyethylene terephthalate was 90% by weight, and the content of butyl acrylate-hydroxyethyl acrylate copolymer was 10% by weight. Heated and melted at 200°C, then electrospun on one side of the PE base film, dried at 60°C for 2 hours, spun on the other side by the same method after drying, and dried at 60°C for 24 hours to obtai...

Embodiment 2

[0088] (1) earlier polyethylene terephthalate is used the N of the silane coupling agent 3-methacryloxypropyltrimethoxysilane of 0.2mol / L, N-dimethylformamide solution at 50 Treat at ℃ for 3h to obtain modified polyethylene terephthalate. The amount of the silane coupling agent is such that the hydroxyl content and carboxyl content on the surface of polyethylene terephthalate are shown in Table 2.

[0089] (2) The modified polyethylene terephthalate prepared in step (1) is mixed with butyl acrylate-hydroxyethyl acrylate copolymer and sodium hexametaphosphate, wherein the modified polyethylene terephthalate The content of the ethylene glycol ester was 85% by weight, the content of the polybutyl acrylate-hydroxyethyl acrylate copolymer was 10% by weight, and the content of the dispersant was 5% by weight. Then heat and melt at 200°C, and perform electrospinning on one side of the PE base film, dry at 60°C for 2 hours, spin on the other side in the same way after drying, and dry...

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Abstract

The invention relates to the technical field of battery materials, and discloses a battery diaphragm, a preparation method thereof, a lithium ion battery and an electric vehicle. The battery diaphragmcomprises a polymer fiber layer, wherein the polymer fiber layer contains polymer fibers, the polymer fibers contain a cross-linked polymer, and the cross-linked polymer is obtained by cross-linkingmodified polyethylene glycol terephthalate and an acrylate polymer; the modified polyethylene glycol terephthalate contains hydroxyl and / or carboxyl, or the modified polyethylene glycol terephthalatehas carbon-carbon double bonds. The battery diaphragm provided by the invention has good thermal shrinkage resistance, more uniformly distributed pores and good air permeability, and can meet the safety and electrochemical performance requirements of a lithium battery.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a battery diaphragm, a method for preparing the battery diaphragm, a battery diaphragm prepared thereby, a lithium ion battery including the battery diaphragm, and an electric vehicle including the lithium ion battery. Background technique [0002] The main function of the separator is to separate the positive and negative electrodes of the battery to prevent short circuit caused by contact between the two electrodes. In addition, it also has the function of allowing electrolyte ions to pass through. Therefore, the performance of the battery separator directly affects the capacity, cycle and safety performance of the battery. , The separator with excellent performance plays an important role in improving the overall performance of the battery. [0003] CN20161006843A discloses a lithium-ion battery ceramic diaphragm slurry, specifically, the lithium-ion battery ceramic ...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/411H01M50/44Y02E60/10
Inventor 高磊刘荣华单军
Owner BYD CO LTD
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