Lithium ion battery diaphragm and preparation method thereof

A lithium-ion battery and diaphragm technology, which is applied in secondary batteries, battery pack components, secondary battery repair/maintenance, etc., can solve the problems of poor adhesion of battery pole pieces, poor flame retardancy, and poor heat resistance of diaphragms, etc. Achieve good adhesion, improve flame retardant function, and improve thermal stability

Active Publication Date: 2017-06-27
CHINA LUCKY FILM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of this, the present invention provides a lithium-ion battery separator co-modified by aromatic polyamide, gel polymer and metal hydroxide to solve the problem of poor heat resistance and poor flame retardancy of the current separator and the separation between battery pole pieces. The problem of poor fit

Method used

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  • Lithium ion battery diaphragm and preparation method thereof
  • Lithium ion battery diaphragm and preparation method thereof
  • Lithium ion battery diaphragm and preparation method thereof

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preparation example Construction

[0035] 3. Preparation method of functional coating modified lithium-ion battery separator

[0036] The invention adopts a wet coating method to prepare a functional coating modified lithium ion battery diaphragm, and the wet coating method is a well-known method for preparing a microporous membrane or a microporous coating.

[0037] (1) Dissolving aromatic polyamide and gel polymer in a certain mass ratio in a solvent respectively, then mixing the two, adding metal hydroxide after mixing evenly, and obtaining a coating liquid after high-speed shearing and stirring. Wherein, the solid content of the coating liquid is 10%-25%.

[0038] (2) Using the polyolefin microporous membrane as the coating substrate, coating the coating solution prepared in step 1 on the surface of the polyolefin microporous membrane to obtain a film A containing a multifunctional coating.

[0039]The method of coating the coating liquid on the surface of the polyolefin microporous membrane is not particu...

Embodiment 1

[0050] (1) Dissolve 90 grams of meta-aramid fibers with a molecular weight of 200,000 and 10 grams of PVDF with a molecular weight of 150,000 in 473.67 grams of DMAc, then mix the two, add 5.26 grams of magnesium hydroxide after mixing, and use high-speed After shearing and stirring, a coating liquid was obtained. At this time, the solid content of the coating solution was 10%, and the mass ratio of inorganic particles to organic substances was 5:95.

[0051] (2) The coating solution was coated on the surface of the PE base film with a thickness of 9 μm by a micro-gravure coating method to obtain a double-sided coated film A.

[0052] (3) The film A was immersed in a coagulation bath with water:EG:DMAc ratio of 80:15:5 for 10 seconds to obtain a film B containing a microporous structure coating.

[0053] (4) Dip the film B into water, stay for 15 seconds, remove the organic solvent on the surface of the film, and dry at 70° C. to obtain the lithium-ion battery separator conta...

Embodiment 2

[0056] (1) 40 grams of meta-aramid fibers with a molecular weight of 300,000 and 60 grams of PVDF with a molecular weight of 150,000 are dissolved in 583.33 grams of DMF respectively, then the two are mixed, and 400 grams of magnesium hydroxide are added after mixing. After shearing and stirring, a coating liquid was obtained. At this time, the solid content of the coating solution was 30%, and the mass ratio of inorganic particles to organic substances was 80:20.

[0057] (2) The coating solution was coated on the surface of the PE base film with a thickness of 9 μm by a micro-gravure coating method to obtain a double-sided coated film A.

[0058] (3) The film A was immersed in a coagulation bath of water: EG: DMAc ratio of 60:25:15 for 10 seconds to obtain a film B containing a microporous structure coating.

[0059] (4) Dip the film B into water, stay for 15 seconds, remove the organic solvent on the surface of the film, and dry at 70° C. to obtain the lithium-ion battery ...

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Abstract

The invention relates to a lithium ion battery diaphragm. The lithium ion battery diaphragm comprises a polyolefin microporous membrane and at least one functional coating applied to the polyolefin microporous membrane. Each functional coating is jointly composed of aromatic polyamide, gel polymers and metal oxides and has properties of high temperature resistance, flame retardation, easiness in fitting with battery pole pieces and the like. The lithium ion battery diaphragm is larger than or equal to 210 DEG C in fusing temperature and larger than or equal to 23% in limit oxygen index. In a battery hot-pressing process, the lithium ion battery diaphragm can well fit the battery pole pieces. The preparation method is convenient and simple in operation, and integral stability in use of batteries can be improved remarkably.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery diaphragm and a preparation method thereof. Background technique [0002] As one of the four major materials of lithium-ion batteries, the separator is a key inner layer component in lithium-ion batteries, although it does not participate in the electrochemical reactions in the battery. The main function of the separator is to isolate the positive and negative electrodes and prevent electrons from passing through, while allowing ions to pass through, thereby completing the rapid transmission of lithium ions between the positive and negative electrodes during charge and discharge. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery. A separator with excellent performance plays an important role in improving the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/42H01M10/0525H01M50/403H01M50/417H01M50/437H01M50/443H01M50/489H01M50/491
CPCH01M10/4235H01M10/0525H01M50/403H01M50/446H01M50/411Y02E60/10
Inventor 高甲安曼胡素芳赵义丽赵伟建程媛
Owner CHINA LUCKY FILM CORP
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