Polyolefin composite separator, preparation method thereof, and lithium-ion battery

A composite diaphragm and polyolefin technology, applied in the field of lithium-ion batteries, can solve the problems of low electrolyte wettability, low liquid absorption rate, and accelerated battery thermal runaway, so as to improve thermal shrinkage resistance, gas permeability, and Effect of Magnification Performance

Active Publication Date: 2017-06-13
JIANGSU HUADONG INST OF LI ION BATTERY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the matrix polymer of the diaphragm, polyolefin has the advantages of high strength, good acid and alkali resistance, and good solvent resistance, but the disadvantage is that the melting point is low (the melting point of polyethylene is about 130 ° C, and the melting point of polypropylene is about 160 ° C), high temperature Easy to extend heat and shrink in the direction of stretching
When the thermal runaway of the battery occurs, the temperature reaches near the melting point of the polymer, the diaphragm shrinks sharply, the positive and negative electrodes of the battery are short-circuited, and the thermal runaway of the battery is accelerated, which in turn leads to safety accidents such as battery fire and explosion.
In addition, polyolefin separators also have disadvantages such as low liquid absorption rate and low electrolyte wettability, which are not conducive to improving the performance of lithium-ion batteries.

Method used

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  • Polyolefin composite separator, preparation method thereof, and lithium-ion battery
  • Polyolefin composite separator, preparation method thereof, and lithium-ion battery
  • Polyolefin composite separator, preparation method thereof, and lithium-ion battery

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preparation example Construction

[0014] Please refer to Figure 1-2 , the embodiment of the present invention provides a preparation method of a polyolefin composite diaphragm, comprising:

[0015] S10, methyl methacrylate (MMA) and γ-methacryloxypropyltriethoxysilane (TEPM) are polymerized in proportion to form a copolymer, and the molecular formula of the copolymer is:

[0016] , where m and n are integers;

[0017] S11, dissolving the copolymer in a first solvent in a certain proportion to form a copolymer solution;

[0018] S12, scrape-coat the copolymer solution on the surface of the polyolefin porous membrane and dry it, so as to form a gel polymer electrolyte prefabricated layer on the surface of the polyolefin porous membrane; and

[0019] S13, fumigate the polyolefin porous separator containing the gel polymer electrolyte prefabricated layer in the atmosphere of hydrochloric acid.

[0020] The step S10 includes the following steps:

[0021] S101, mixing methyl methacrylate and γ-methacryloxypro...

Embodiment 1

[0042] Mix methyl methacrylate and γ-methacryloxypropyltriethoxysilane evenly at a molar ratio of 1:1, then add a certain amount of azobisisobutyronitrile (AIBN), at 80°C Stirring polymerization forms a copolymer prepolymer; the copolymer prepolymer is dissolved in tetrahydrofuran to form a mixed solution of the copolymer prepolymer, and the mixed solution of the copolymer prepolymer is added to ethanol / water (volume Precipitation in a mixed solvent with a ratio of 1:1), and repeated three times, so as to obtain the precipitation of a copolymer of polymethyl methacrylate-polyγ-methacryloxypropyltriethoxysilane; the copolymerization The substance is dissolved in tetrahydrofuran to form a copolymer solution with a concentration of about 10%; the copolymer solution is scraped on the two surfaces of a Celgard-2325 type diaphragm and dried; the Celgard-2325 type diaphragm coated with the copolymer solution The diaphragm was fumigated in a concentrated hydrochloric acid atmosphere f...

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Abstract

A method for preparing a polyolefin composite diaphragm, comprising: polymerizing methyl methacrylate and γ-methacryloxypropyltriethoxysilane in proportion to form a copolymer, the molecular formula of the copolymer is:, Wherein, m and n are integers; the copolymer is dissolved in the first solvent to form a copolymer solution; the copolymer solution is scraped on the surface of the polyolefin porous membrane and dried, so that the polyolefin porous A gel polymer electrolyte prefabricated layer is formed on the surface and inner pore walls of the diaphragm; and the polyolefin porous diaphragm containing the gel polymer electrolyte prefabricated layer is fumigated in an atmosphere of hydrochloric acid. The invention also relates to a polyolefin composite diaphragm and a lithium ion battery.

Description

technical field [0001] The invention relates to a polyolefin composite diaphragm, a preparation method thereof, and a lithium ion battery using the polyolefin composite diaphragm. Background technique [0002] With the rapid development of lithium-ion batteries in new energy applications such as mobile phones, electric vehicles and energy storage systems, the safety of lithium-ion batteries is particularly important. Based on the analysis of the reasons for the safety of lithium-ion batteries, the safety of lithium-ion batteries can be improved from the following aspects: First, by optimizing the design and management of lithium-ion batteries, real-time monitoring and processing of the charging and discharging process of lithium-ion batteries , to ensure the safety of lithium-ion batteries, the second is to improve or develop new electrode materials to improve the intrinsic safety performance of the battery, and the third is to use a new type of safe electrolyte and diaphrag...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/42C08F230/08C08F220/14H01M2/16H01M10/0525H01M50/403H01M50/414H01M50/417H01M50/42H01M50/449
CPCC08F220/14C08J5/2243C08J2323/12C08J2433/12H01M10/052H01M10/0565H01M2300/0082Y02E60/10H01M50/403H01M50/449C08F230/085H01M50/417H01M50/42H01M10/0525C08J7/16C08J9/365C08J2323/02C09D4/00
Inventor 赵鹏何向明尚玉明王莉杨聚平李建军高剑王要武
Owner JIANGSU HUADONG INST OF LI ION BATTERY
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