Polyolefin composite membrane and preparation method thereof as well as lithium ion battery

A technology of composite diaphragm and polyolefin

Active Publication Date: 2014-10-29
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 and low gas permeability, which are not conducive to improving the performance of lithium-ion batteries.

Method used

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  • Polyolefin composite membrane and preparation method thereof as well as lithium ion battery
  • Polyolefin composite membrane and preparation method thereof as well as 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 and polyvinylidene fluoride (PVdF) in a first solvent to form a first solution;

[0018] S12, providing a polyolefin porous membrane, and soaking the polyolefin porous membrane in a second solvent;

[0019] S13, coating the first solution on at least one side of the polyolefin porous membrane soaked with the second solvent;

[0020] S14, immersing the polyolefin porous membrane coated with the first solution into the third solvent to drill holes, thereby forming a gel polymer electrolyte prefabricated layer on the surface of the polyolefin porous membrane, the ...

Embodiment 1

[0046] 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 and polymerization to form 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 ratio 1:1) mixed solvent for precipitation, and repeated three times to obtain polymethyl methacrylate-poly γ-methacryloxypropyltriethoxysilane copolymer precipitation; the copolymer precipitation and Polyvinylidene fluoride is mixed according to the mass ratio of 1:2, and dissolved in tetrahydrofuran to prepare the first solution with a concentration of about 10%; the first solution is scraped on the two surfaces of the Celgard-2325 diaphragm; the scraper is coated with The Celgard-2325 diaphragm of the first solution is immersed in a mixed solvent of ethan...

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Abstract

The invention relates to a preparation method of a polyolefin composite membrane. The method comprises the following steps of polymerizing methyl methacrylate and gamma-3-(Triethoxysilyl)propyl methacrylate in proportion to form a copolymer with the molecular formula shown in the description; dissolving the copolymer and polyvinylidene fluoride into a first solvent to form a first solution; soaking a perforated polyolefin membrane into a second solvent; coating at least one surface of the perforated polyolefin membrane (which is soaked in the second solvent) with the first solution; soaking the perforated polyolefin membrane coated with the first solution into a third solvent, and punching to form a gel polymer electrolyte prefabrication layer on the surface of the perforated polyolefin membrane; and performing fumigation on the perforated polyolefin membrane with the gel polymer electrolyte prefabrication layer in hydrochloric acid atmosphere. The invention also relates to the polyolefin composite membrane 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 Applications(China)
IPC IPC(8): H01M2/16H01M10/0525C08J7/043H01M50/403H01M50/417H01M50/42H01M50/426H01M50/449
CPCH01M10/0525H01M50/403H01M50/426H01M50/42H01M50/417H01M50/449C08J2323/02C08J2433/04H01M10/0565H01M2300/0085B32B27/304B32B2260/02B32B27/08B32B27/308B32B2260/046B32B27/205B32B2255/26B32B2457/10B32B2255/10B32B27/32C08J7/0427Y02E60/10C08J7/043B32B27/00
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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