Polyimide diaphragm and preparation method thereof

A technology of polyimide and polyamic acid is applied in the field of polyimide diaphragm and its preparation, which can solve the problems of high temperature resistance, deformation, and potential safety hazards of power lithium battery of the diaphragm, so as to achieve good rigidity, flexibility, simple process, The effect of good thermal stability

Active Publication Date: 2020-11-03
HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, the base film of the lithium battery diaphragm produced in the market is mostly made of PE film. The diaphragm is not resistant to high temperature and will be seriously deformed in the environment of 130 ℃, which has great potential safety hazards for power lithium batteries.
Lithium batteries with high capacity density will generate high temperature when releasing energy. PE separator can no longer meet the needs of the existing market. Now a separator that can withstand high temperature and work in high temperature environment for a long time is needed.

Method used

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  • Polyimide diaphragm and preparation method thereof
  • Polyimide diaphragm and preparation method thereof
  • Polyimide diaphragm and preparation method thereof

Examples

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Comparison scheme
Effect test

Embodiment 1

[0048] A kind of preparation method of polyimide diaphragm of the present invention, comprises the following steps:

[0049]Step 1: under the condition of nitrogen protection, add the N-methylpyrrolidone after dehydration into the reaction tank, then add p-phenylenediamine into the reaction tank, stir at 30r / min for 15min to fully dissolve the p-phenylenediamine, and obtain The first mixed solution; feed chilled water into the jacket of the reaction tank, after cooling the first mixed solution in the reaction tank to 7°C, add pyromellitic dianhydride to the first mixed solution to obtain For the second mixed solution, the temperature of the second mixed solution is gradually raised to 15° C. and maintained at this temperature, and stirred at 30 r / min for 20 minutes to fully carry out the reaction in the second mixed solution to obtain a polyamic acid solution; wherein, in the In the second mixed solution, the mass fraction of N-methylpyrrolidone is 95wt%, the total mass fracti...

Embodiment 2

[0061] A kind of preparation method of polyimide diaphragm of the present invention, comprises the following steps:

[0062] Step 1: Under the condition of nitrogen protection, add the dehydrated N-methylpyrrolidone into the reaction tank, then add 4,4-diaminodimethyl ether into the reaction tank, stir at 35r / min for 18min to make 4,4 -Diaminodimethyl ether is fully dissolved to obtain the first mixed solution; into the jacket of the reaction tank, chilled water is passed, and after the first mixed solution in the reaction tank is cooled to 10°C, the first mixed solution is added to the first mixed solution Pyromellitic dianhydride was added to obtain the second mixed solution, and the second mixed solution was gradually warmed up to 18°C ​​and kept at this temperature, stirred at 35r / min for 20min to fully proceed the reaction in the second mixed solution, and obtained Polyamic acid solution; wherein, in the second mixed solution, the mass fraction of N-methylpyrrolidone is 9...

Embodiment 3

[0074] A kind of preparation method of polyimide diaphragm of the present invention, comprises the following steps:

[0075] Step 1: Under the condition of nitrogen protection, add the N-methylpyrrolidone after dehydration into the reaction tank, then add p-phenylenediamine into the reaction tank, stir at 40r / min for 20min to fully dissolve the p-phenylenediamine, and obtain The first mixed solution; into the jacket of the reaction tank, chilled water is passed, and after the first mixed solution in the reaction tank is cooled to 12°C, 3,3,4,4- Biphenyltetracarboxylic dianhydride to obtain the second mixed solution, gradually warming the second mixed solution to 20°C and maintaining the temperature, stirring at 40r / min for 20min to fully proceed the reaction in the second mixed solution to obtain polyamide acid solution; wherein, in the second mixed solution, the mass fraction of N-methylpyrrolidone is 95wt%, and the total mass fraction of p-phenylenediamine and 3,3,4,4-biphen...

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Abstract

The invention discloses a preparation method of a polyimide diaphragm, which comprises the following steps: reacting p-phenylenediamine or 4,4-diaminodimethyl ether with pyromellitic dianhydride or 3,3,4,4-biphenyl tetracarboxylic dianhydride in N-methyl pyrrolidone to obtain a polyamide acid solution; uniformly mixing the polyamic acid solution with dimethyl carbonate to obtain polyamic acid slurry; spreading the polyamide acid slurry uniformly on the horizontal conveying film by controlling the thickness of the polyamide acid slurry, wherein the polyamide acid slurry uniformly adheres to thehorizontal conveying film, and a polyamide acid film is obtained; and extracting the polyamide acid film, removing the horizontal transfer film, drying the film to obtain a diaphragm precursor, and dehydrating the film at high temperature to obtain the polyimide diaphragm. According to the invention, the molecular structure is designed, so that the prepared polyimide diaphragm has better rigidityand flexibility; in addition, a large number of hydrogen bonds appear among polyimide molecules, and the interaction among the polyimide molecules is improved, so that the prepared polyimide diaphragm has relatively good thermal stability.

Description

technical field [0001] The invention relates to the technical field of lithium battery diaphragms, in particular to a polyimide diaphragm and a preparation method thereof. Background technique [0002] At present, the base film of the lithium battery diaphragm produced in the market mostly uses PE film, and the diaphragm is not resistant to high temperature, and will be seriously deformed in an environment of 130°C, which has great potential safety hazards for power lithium batteries. Lithium batteries with high capacity density will generate high temperature when releasing energy. PE separators can no longer meet the needs of the existing market. Now there is a need for a separator that can withstand high temperatures and work in high temperature environments for a long time. Contents of the invention [0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method of a polyimide diaphragm. [0004] Another o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G73/10C08J5/18H01M2/14H01M2/16H01M10/052C08L79/08
CPCC08G73/1067C08G73/1071C08G73/1007C08J5/18H01M10/052C08J2379/08Y02E60/10
Inventor 袁海朝徐锋李腾苏碧海
Owner HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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