A kind of polyolefin multilayer microporous film for lithium ion battery and preparation method thereof

A kind of technology of lithium ion battery and microporous membrane

Active Publication Date: 2015-12-02
河南惠强新能源材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Coating improvement on a single-layer PE or PP film will cause coating peeling and pore blocking, which reduces the porosity of the separator, which is not conducive to high-current charging and discharging, and its cycle life and safety performance are poor.
If the porosity is increased, the thermal shrinkage performance of the separator will be deteriorated, and the safety performance of the battery will be poor
Good thermal stability can be obtained by compounding PE and PP, but the three-layer composite separator currently mainly used has the problems of low porosity, small pore size, poor lyophilicity, low interfacial peel strength, and high impedance, which cannot meet the requirements of power lithium at the same time. Ion battery high power demand

Method used

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  • A kind of polyolefin multilayer microporous film for lithium ion battery and preparation method thereof
  • A kind of polyolefin multilayer microporous film for lithium ion battery and preparation method thereof
  • A kind of polyolefin multilayer microporous film for lithium ion battery and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0064] Preparation of polyethylene microporous layer: Get 20% high-density polyethylene and 80% liquid paraffin in a twin-screw extruder at 200 ° C by weight, form an oil film on a cooling roll at 25 ° C, and heat the above oil film at 120 ° C Two-way simultaneous stretching is carried out, the stretching ratio is 5×5, and the stretched oil film is subjected to heat setting treatment at 130°C for 20s. The high-boiling-point solvent in the solvent is eluted with dichloromethane extractant, and then dried to obtain a polyethylene microporous layer.

[0065] Preparation of the polypropylene microporous layer: the polypropylene was melt-extruded at 230° C. with an extrusion device, and then cooled to 90° C. for uniaxial stretching to obtain a polypropylene microporous layer.

[0066] Preparation of the ion acceleration layer: Add polyvinylidene fluoride to a mixture of acetone:glycerol=10:1, and prepare an ion acceleration layer solution at a mass ratio of polyvinylidene fluoride:...

Embodiment 2

[0069] Preparation of polyethylene microporous layer: Get 20% high-density polyethylene and 80% liquid paraffin in a twin-screw extruder at 200 ° C by weight, form an oil film on a cooling roll at 25 ° C, and heat the above oil film at 120 ° C Carry out two-way simultaneous stretching with a stretching ratio of 5×5, and heat-setting the stretched oil film at 130°C for 20s. The high-boiling-point solvent in the solvent is eluted with dichloromethane extractant, and then dried to obtain a polyethylene microporous membrane.

[0070] Preparation of the polypropylene microporous layer: the polypropylene was melt-extruded at 230° C. with an extrusion device, and then cooled to 90° C. for uniaxial stretching to obtain a polypropylene microporous layer.

[0071] Preparation of the ion acceleration layer: Add polyvinylidene fluoride and dioctyl phthalate to acetone, and prepare according to the mass ratio of polyvinylidene fluoride: dioctyl phthalate: acetone = 1:0.1:12 into ion accel...

Embodiment 3

[0074]Preparation of polyethylene microporous layer: Get 20% high-density polyethylene and 80% liquid paraffin in a twin-screw extruder at 200 ° C by weight, form an oil film on a cooling roll at 25 ° C, and heat the above oil film at 120 ° C Carry out two-way simultaneous stretching with a stretching ratio of 5×5, and heat-setting the stretched oil film at 130°C for 20s. The high-boiling-point solvent in the solvent is eluted with dichloromethane extractant, and then dried to obtain a polyethylene microporous membrane.

[0075] Preparation of the polypropylene microporous layer: the polypropylene was melt-extruded at 230° C. with an extrusion device, and then cooled to 90° C. for uniaxial stretching to obtain a polypropylene microporous layer.

[0076] Preparation of the ion acceleration layer: Add polyvinylidene fluoride to a mixture of acetone:glycerol=10:1, and prepare an ion acceleration layer solution at a mass ratio of polyvinylidene fluoride:mixture=1:15.

[0077] Pre...

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Abstract

The invention relates to a polyolefin multilayer microporous film for lithium ion batteries and a preparation method thereof. The polyolefin multilayer microporous film includes a polyethylene microporous layer, and each of the upper and lower surfaces of the polyethylene microporous layer has a An ion accelerating layer, each having a polypropylene microporous layer on the outer surfaces of the ion accelerating layers. The five-layer structure of the present invention can provide a lower closed cell temperature and a higher membrane rupture temperature of the diaphragm, increase the safety window of the diaphragm, and provide good safety performance; at the same time, the ion acceleration layer provides the diaphragm with low resistance and high electron conductivity And good liquid absorption performance and liquid retention performance, can improve the charge and discharge power and cycle life of lithium-ion batteries; the ion acceleration layer has a microporous network structure, and has excellent lyophilic performance and bonding performance, which can ensure that While each layer of the microporous membrane is well compounded, the ion transmission performance of the separator is improved, and good air permeability is maintained.

Description

technical field [0001] The invention relates to a diaphragm material for lithium ion batteries and a preparation method thereof, in particular to a polyolefin multilayer microporous film applied to electrochemical energy storage devices such as lithium ion secondary batteries and a preparation method thereof. Background technique [0002] The lithium-ion battery separator is one of the important components of the lithium-ion battery that is used in the lithium-ion battery to isolate the positive and negative electrodes to prevent battery short circuit and has a certain pore structure to ensure the smooth passage of lithium ions. This separator can be used in lithium-ion batteries for communications such as electronic products and electrical equipment. In recent years, research on lithium secondary batteries as power sources for electric vehicles and hybrid vehicles has been carried out. This type of high-end lithium-ion batteries requires high power output, high capacity, ex...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M2/18H01M50/403H01M50/417H01M50/457H01M50/491
CPCH01M50/403H01M50/449Y02E60/10
Inventor 王松钊林妙云吴耀根蔡朝辉廖凯明
Owner 河南惠强新能源材料科技股份有限公司
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