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Preparation of polyimide porous membrane

A polyimide and polyamic acid film technology, applied in structural parts, battery pack parts, electrical components, etc., can solve the problems of poor heat resistance and poor mechanical strength of polyimide film, and achieve process and equipment. Simple, high mechanical strength, good universality

Active Publication Date: 2011-12-14
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the disadvantages that the preparation method of the polyimide porous membrane in the prior art needs to add additional pore-forming substances and the prepared polyimide membrane has poor heat resistance and poor mechanical strength. Preparation method of additionally adding pore-forming substances and capable of preparing polyimide porous membrane with good mechanical strength and good heat resistance

Method used

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  • Preparation of polyimide porous membrane
  • Preparation of polyimide porous membrane
  • Preparation of polyimide porous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0039] According to a preferred embodiment of the present invention, the preparation method of polyimide porous membrane provided by the present invention comprises the steps:

[0040] (1) Add tetraacid dianhydride and organic diamine into the solvent at a molar ratio of 0.8-1.2:1, stir and react at 20-70°C for 3-15 hours, then degas under vacuum at the same temperature for 1-12 hours Obtain polyamic acid solution;

[0041] (2) Under the condition that the temperature is 10-40°C and the relative humidity is 40-80%, the above-mentioned polyamic acid solution is coated on a stainless steel or glass support, dried naturally, and the polyamic acid solution of 50-600 microns is obtained after removing the solvent. Amic acid film;

[0042] (3) Put the support body of the above polyamic acid film into the coagulation solution at 10-50° C. and immerse for 1-30 minutes to solidify and form holes to obtain a porous polyamic acid film;

[0043] (4) Soak and clean the porous polyamic ac...

Embodiment 1

[0056] This example is used to illustrate the preparation method of the polyimide porous membrane provided by the present invention.

[0057] (1) 4,4'-diaminodiphenyl ether and pyromellitic dianhydride are added to the weight of 4,4'-diaminodiphenyl ether and pyromellitic dianhydride in a molar ratio of 1:1 In N,N-dimethylacetamide with a total weight of 9 times, stirred and reacted at 25°C for 5 hours, then vacuum degassed at this temperature for 1 hour to obtain a viscous polyamic acid solution. The characteristics of the solution Viscosity η int = 150 ml / g (measurement conditions: Ubbelohde viscometer, constant temperature 30°C, the solution is diluted to a solid content of 0.005 g / ml);

[0058] (2) At a temperature of 10°C and a relative humidity of 40%, the above polyamic acid solution was coated on a stainless steel plate, and dried naturally for 20 minutes to obtain a polyamic acid film;

[0059] (3) The above-mentioned stainless steel plate with the polyamic acid fil...

Embodiment 2

[0062] This example is used to illustrate the preparation method of the polyimide porous membrane provided by the present invention.

[0063] (1) 4,4'-diaminodiphenyl ether and BTDA are added to N,N-diphenyl ether and BTDA whose weight is 4 times the total weight of 4,4'-diaminodiphenyl ether and BTDA in a molar ratio of 1:1. In methyl acetamide, stirred and reacted at 45°C for 10 hours and then vacuum degassed at this temperature for 1 hour to obtain a viscous polyamic acid solution. The intrinsic viscosity of the solution η int = 180 ml / g (measurement conditions: Ubbelohde viscometer, constant temperature 30°C, the solution is diluted to a solid content of 0.005 g / ml);

[0064] (2) At a temperature of 20°C and a relative humidity of 60%, the above-mentioned polyamic acid solution was coated on a stainless steel plate, and the polyamic acid film was obtained after natural drying for 10 minutes;

[0065] (3) Dip the above-mentioned stainless steel plate with polyamic acid fil...

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Abstract

The invention provides a method for preparing a polyimide porous membrane. The method comprises the formation of a polyamic acid membrane by a polyamic acid solution and the amination of the polyamic acid membrane, wherein the method also comprises the following: before the amination of the polyamic acid membrane, the polyamic acid membrane is solidified and pore-formed to obtain a porous polyamic acid membrane. In the method for preparing the polyimide porous membrane, because pore-formed materials are not contained in the polyamic acid solution, the obtained polyimide porous membrane does not contain impurities, thereby having higher chemical stability, better high-temperature resisting property and higher mechanical strength. The polyimide porous membrane prepared by the method can be used as a battery diaphragm in a high-capacity power battery.

Description

technical field [0001] The invention relates to a preparation method of a polyimide porous membrane. Background technique [0002] Lithium-ion batteries consist of electrodes, electrolytes, and polymer separators. Between the positive and negative stages of a lithium-ion battery is a polymer separator. As a key component of lithium-ion batteries, the main function of the polymer separator is to block the positive and negative electrodes to prevent internal short circuit of the battery, but to allow the ion flow to pass through quickly to complete the rapid transfer of lithium ions between the positive and negative electrodes during electrochemical charging and discharging. transmission. As lithium batteries become more and more compact, the requirements for separators are also getting higher and higher. The role of the separator is very important, directly affecting the discharge capacity and cycle life of the battery. One of the safety measures for lithium-ion batteries...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16C08L79/08C08J5/18H01M50/403H01M50/417H01M50/423H01M50/489H01M50/491
CPCY02E60/12Y02E60/10
Inventor 饶先花胡娟张凌紫江林宫清
Owner BYD CO LTD