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A kind of polyethylene microporous diaphragm containing organic/inorganic composite cross-linked coating and preparation method thereof

A polyethylene microporous film, inorganic composite technology, applied in electrical components, circuits, battery pack parts and other directions, can solve the problems of insufficient bonding force, affecting battery performance, poor bonding force, etc., and reaching the temperature of thermal shrinkage film breaking Improve, enhance the safety performance, the effect of low closed-cell temperature

Active Publication Date: 2016-08-31
扬州市永佳车辆配件有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the use of coating technology to improve the heat resistance of polyethylene battery separator materials also brings other problems: (1) The bonding force between the coating and the separator is poor, and it is easy to cause peeling off during battery processing, which affects the battery life. (2) It is difficult for the inorganic powder to form a uniform dispersion in the organic polymer coating, and the binding force between the inorganic particles and the organic polymer is not high enough, which reduces the strength and thermal stability of the composite coating; (3 ) The surface coating formed is easy to block the original micropores of the microporous membrane, reduce the original porosity and air permeability of the microporous membrane, hinder ion conduction, and thus affect the performance of the battery

Method used

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  • A kind of polyethylene microporous diaphragm containing organic/inorganic composite cross-linked coating and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The polyethylene microporous membrane prepared by the uniaxial stretching process is used as the coating base membrane. Its thickness is 20.5 μm, the porosity is 47.8%, and the Gurley value reflecting the air permeability is 368s. The two surfaces of the polyethylene microporous membrane were treated with the same degree of normal temperature and low pressure plasma treatment, using air as the treatment atmosphere, and the base film was treated for 30 seconds at room temperature (25 ° C), 45W power and 60Pa vacuum condition, and the plasma The water contact angle of the basement film surface decreased from 105° to 37° after bulk treatment, and the treated basement film was used for the coating process within 15 minutes.

[0039] Mix diphenyl diisocyanate (MDI) and dicyclohexylmethane diisocyanate (HMDI) uniformly in a molar ratio of 50:50 as an aromatic diisocyanate, select a molecular weight of 1000, a hydroxyl value of 112mgKOH / g, and a molecular chain In terephthalic...

Embodiment 2

[0045] The polyethylene microporous membrane treated with normal temperature and low pressure plasma in Example 1 was used as the coating base membrane. The molecular weight in the coating solution of Example 1 is 1000, the hydroxyl value is 112mgKOH / g, and the polyester diol containing aromatic heterocyclic structure is 55:45 in the mole ratio of terephthalic acid and phthalic anhydride in the molecular chain Respectively replaced by polyester diols containing aromatic heterocyclic structures with molecular weights of 500, 1500, and 2000, their hydroxyl values ​​were 224, 74.8, and 56 mgKOH / g, and terephthalic acid and phthalic anhydride in the molecular chain The molar ratios are all 55:45. Other components and dosages in the coating solution were still the same as in Example 1, and three coating solutions were prepared respectively. Then according to the coating process and curing process in Example 1, three kinds of polyethylene microporous membranes with different cross-...

Embodiment 3

[0050] The polyethylene microporous membrane treated with normal temperature and low pressure plasma in Example 1 was used as the coating base membrane. The molecular weight in the coating solution of Example 1 is 1000, the hydroxyl value is 112mgKOH / g, and the polyester diol containing aromatic heterocyclic structure is 55:45 in the mole ratio of terephthalic acid and phthalic anhydride in the molecular chain Respectively replaced by terephthalic acid and phthalic anhydride molar ratio of 35:65, 45:55, 65:35, 75:25 polyester diol containing aromatic heterocyclic structure in the molecular chain, their molecular weight Both are 1000, and the hydroxyl value is 112mgKOH / g.

[0051] Other components and consumption in the coating solution are still the same as in Example 1. Coating solutions were prepared separately. It is found that terephthalic acid and phthalic anhydride mol ratio are 75:25 containing the polyester diol of aromatic heterocyclic structure in molecular chain a...

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Abstract

The invention belongs to the field of functional polymer film preparation, and particularly relates to a polyethylene microporous film containing an organic / inorganic composite cross-linked coating for improving the safety of lithium ion batteries and its preparation method. The invention uses aromatic heterocyclic polyester diol and aromatic isocyanate as basic components, combines cross-linking agent, foaming agent, catalyst and inorganic nano filler, and prepares a coating liquid according to a certain composition ratio; The liquid is coated on at least one surface of the polyethylene microporous separator, and after curing under specific temperature conditions, an organic polymer / inorganic nanoparticle composite cross-linked coating with an open-pore foam structure is formed on the surface of the polyethylene microporous separator. The polyethylene microporous separator of the present invention can significantly increase the thermal shrinkage rupture temperature while maintaining high porosity and air permeability. When used as a separator material for power lithium ion batteries, the safety performance of the battery can be significantly improved.

Description

technical field [0001] The invention belongs to the field of preparation of functional polymer films, in particular to a polyethylene microporous film containing an organic / inorganic composite cross-linked coating for improving the safety of lithium-ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the characteristics of long cycle life, high specific energy, and no memory effect. They are widely used in rechargeable batteries for portable electronic products such as mobile phones, notebook computers, and camcorders, as well as power sources for environmentally friendly electric vehicles. The microporous diaphragm is an important part of the lithium-ion battery. Its function is to prevent the physical contact between the positive and negative materials, and allow the ion flow to pass through the micropores of the diaphragm, so as to ensure that the lithium ions are in the positive and negative state during the charging an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M2/18H01M50/403H01M50/417H01M50/431H01M50/443H01M50/446H01M50/449H01M50/491
CPCY02E60/10
Inventor 俞强程向君蒋姗丁永红张洪文王克敏刘晶如朱梦冰
Owner 扬州市永佳车辆配件有限公司