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Low-stress lithium-ion battery separator and preparation method thereof

A lithium-ion battery, low-stress technology, applied in the direction of secondary batteries, battery pack components, circuits, etc., can solve the problems of reduced strength, inability to release, and easy shrinkage and deformation

Inactive Publication Date: 2019-11-12
高芳
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The diaphragm is the key core material for blocking the short circuit of the positive and negative electrodes of the lithium-ion battery. The existing preparation technology of the diaphragm material is mainly a wet process, which is formed by high-temperature casting and multiple multi-stage stretching. The uniformity and flatness of the material thickness. During the preparation pr

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A low-stress lithium-ion battery separator, the components and their weight parts are: 50 parts of polyethylene, 30 parts of polypropylene, 20 parts of polyolefin, and 0.5 part of a pore-forming agent.

[0021] A method for preparing a low-stress lithium-ion battery diaphragm of the present invention, comprising the following steps:

[0022] Step 1. Composite polyethylene, polypropylene, polyolefin raw materials and pore-forming agents, after high-temperature melting casting and cooling to form a film, stretching longitudinally and transversely;

[0023] Step 2, low temperature stress relief: the biaxially stretched film is subjected to low temperature setting treatment;

[0024] Step 3. Remove the pore-forming agent through conventional chemical extraction, wash with deionized water, and dry at low temperature;

[0025] Step 4. Chemical stress relief: the extracted semi-finished diaphragm is modified by chemical stress process to the melted and stretched polyolefin st...

Embodiment 2

[0031] A low-stress lithium-ion battery separator, the components and their weight parts are: 55 parts of polyethylene, 40 parts of polypropylene, 25 parts of polyolefin, and 1.5 parts of pore-forming agent.

[0032] A method for preparing a low-stress lithium-ion battery diaphragm of the present invention, comprising the following steps:

[0033] Step 1. Composite polyethylene, polypropylene, polyolefin raw materials and pore-forming agents, after high-temperature melting casting and cooling to form a film, stretching longitudinally and transversely;

[0034] Step 2, low temperature stress relief: the biaxially stretched film is subjected to low temperature setting treatment;

[0035] Step 3. Remove the pore-forming agent through conventional chemical extraction, wash with deionized water, and dry at low temperature;

[0036] Step 4. Chemical stress relief: the extracted semi-finished diaphragm is modified by chemical stress process to the melted and stretched polyolefin str...

Embodiment 3

[0042] A low-stress lithium-ion battery separator, the components and their weight parts are: 60 parts of polyethylene, 50 parts of polypropylene, 30 parts of polyolefin, and 2 parts of pore-forming agent.

[0043] A method for preparing a low-stress lithium-ion battery diaphragm of the present invention, comprising the following steps:

[0044] Step 1. Composite polyethylene, polypropylene, polyolefin raw materials and pore-forming agents, after high-temperature melting casting and cooling to form a film, stretching longitudinally and transversely;

[0045] Step 2, low temperature stress relief: the biaxially stretched film is subjected to low temperature setting treatment;

[0046] Step 3. Remove the pore-forming agent through conventional chemical extraction, wash with deionized water, and dry at low temperature;

[0047] Step 4. Chemical stress relief: the extracted semi-finished diaphragm is modified by chemical stress process to the melted and stretched polyolefin struc...

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PUM

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Abstract

The invention discloses a low-stress lithium-ion battery separator and a preparation method thereof and belongs to the technical field of lithium batteries. The low-stress lithium-ion battery separator is prepared from the following components in parts by weight: 50-60 parts of polyethylene, 30-50 parts of polypropylene, 20-30 parts of polyolefin and 0.5-2 parts of a pore-forming agent. The invention further provides a preparation method of the low-stress lithium-ion battery separator. According to the low-stress lithium-ion battery separator, residual stress is relaxed to be removed through an internal local plastic deformation or local relaxation process of the separator at certain temperature during low-temperature destressing. The low-stress lithium-ion battery separator is slowly heated to relatively low temperature in general during destressing and is slowly cooled after being kept for a period of time to prevent generation of new residual stress. The prepared low-stress lithium-ion battery separator is an ultrathin high-strength separator material and is suitable for promotion and application.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and relates to a low-stress lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] The diaphragm is the key core material for blocking the short circuit of the positive and negative electrodes of the lithium-ion battery. The existing preparation technology of the diaphragm material is mainly a wet process, which is formed by high-temperature casting and multiple multi-stage stretching. The uniformity and flatness of the material thickness. During the preparation process, the diaphragm material is always in a strong tensile environment. The tensile stress generated by the stretching always exists in the diaphragm material structure and cannot be released, which leads to the diaphragm material in the actual application process. The medium strength decreases, and it is prone to shrinkage and deformation, which has a serious impact on the safe use of t...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/411Y02E60/10
Inventor 高保清舒均国陈立新高芳
Owner 高芳
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