A kind of anti-overcharge lithium battery composite diaphragm and preparation method thereof

A composite diaphragm and anti-overcharge technology, which is applied in the direction of separators/films/diaphragms/spacer components, circuits, electrical components, etc., can solve problems such as the inability to form a conductive network and the weak bonding force of the ceramic coating base film, and achieve Good application prospects, simple and easy preparation process, and environment-friendly effect

Active Publication Date: 2020-03-20
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the ceramic coating obtained by this method has problems such as weak binding force with the base film and inability to form an effective conductive network, and does not fundamentally solve the problem of the existing separator. The bottleneck of the rapid development of new energy fields such as energy storage

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0026] The preparation method of the anti-overcharge lithium battery composite diaphragm comprises the following steps:

[0027] (1) For the pretreatment of the porous base film, under the assistance of ultrasonic waves, wash the base film in ethanol and acetone respectively to ensure that the surface and internal structure of the base film are free of impurities, then dry at low temperature and set aside.

[0028] (2) Prepare the conductive polymer monomer solution, select the appropriate conductive polymer monomer according to the requirements of the battery for the anti-overcharge voltage level of the separator, and prepare a monomer solution with a certain concentration.

[0029] (3) Basement membrane absorbs polymer monomer and monomer polymerization, immerses the impurity-removed basement membrane in the monomer solution, and promotes the diffusion of monomer molecules into the basement membrane by ultrasonic treatment, then takes out the basement membrane and drys it at ...

Embodiment 1

[0037] In this embodiment, a polyethylene diaphragm with an average pore diameter of 50 nanometers, a porosity of 45%, and a thickness of 12 microns is selected as the base film, and the base film with a size of 5 cm × 2 cm is washed in acetone and ethanol solutions respectively, and assisted by ultrasonic Treat for 30 minutes, then dry at 80°C and set aside.

[0038] Using chloroform as a solvent, a triphenylamine solution with a mass concentration of 2.5% was prepared. After it was completely dissolved, the above-mentioned polyethylene diaphragm was immersed in it, and treated with ultrasonic assistance for 15 minutes, and then the diaphragm was taken out and dried at 60°C. Put the diaphragm impregnated with triphenylamine monomer into excess ferric chloride methanol solution (mass concentration of ferric chloride is 20%), use high-purity nitrogen (volume concentration 99.999%) as protective gas, and keep at 25°C After reacting for 24 hours, the diaphragm was washed 3 to 5 t...

Embodiment 2

[0044] In this embodiment, a polyacrylonitrile nanofiber membrane with an average pore diameter of 1200 nanometers, a porosity of 78%, and a thickness of 32 microns is selected as the base membrane, and the base membrane with a size of 5 cm × 2 cm is washed in acetone and ethanol solutions respectively. And assisted by ultrasonic treatment for 30 minutes, then dried at 100°C for later use.

[0045] Using chloroform as a solvent, a tributylthiophene solution with a mass concentration of 8% was prepared. After it was completely dissolved, the above-mentioned nanofiber diaphragm was immersed in it, and treated with ultrasonic assistance for 30 minutes, and then the diaphragm was taken out and dried at 120°C. Put the diaphragm impregnated with tributylthiophene monomer into excess sodium persulfate ethanol solution (mass concentration of sodium persulfate is 40%), use high-purity nitrogen (volume concentration 99.999%) as protective gas, and keep it at 0°C After reacting for 16 hour...

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Abstract

The invention relates to the field of lithium battery diaphragms and preparation thereof, in particular to an anti-overcharge composite lithium battery diaphragm and a preparation method thereof, thecomposite diaphragm comprises a base diaphragm and anti-overcharge conducting polymers distributed in a three-dimensional structure of the base diaphragm, the base diaphragm is a porous diaphragm witha strong porous structure, the conducting polymers are adhered into network holes of the base diaphragm through in-situ polymerization, the preparation method includes the steps of pretreating the surface of the porous base diaphragm, preparing a conducting polymer monomer solution, adsorbing polymer monomers by the base diaphragm, performing monomer polymerization, post-treating the composite diaphragm and the like, and finally, the composite lithium battery diaphragm with an overcharge resisting function is obtained, the anti-overcharge composite lithium battery diaphragm has the advantagesof physical and chemical stability, adjustable aperture size and the like, can prevent batteries from being overcharged during use to the greatest extent, and has a good application prospect in lithium batteries, the preparation process is simple and easy to operate, the cost is low, and environmental friendliness is realized.

Description

technical field [0001] The invention relates to the field of lithium ion battery diaphragm and its preparation, in particular to an anti-overcharge lithium battery composite diaphragm and its preparation method. Background technique [0002] The battery separator is a kind of porous film, which is an important part of the lithium-ion battery, and it directly affects the safety and cost of the lithium-ion battery. The conductivity in the diaphragm has a direct impact on the overall performance of the lithium-ion battery. It has a micropore self-closing protection function, which can better protect the battery from overheating and current flow caused by overcharging or temperature rise. The increase, thus preventing the explosion caused by the short circuit of the battery, plays a role of safety protection for the battery. At the same time, the performance of the separator also affects the interface structure and internal resistance of the battery, so it also affects the capa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M2/18H01M10/0525
CPCH01M10/0525H01M50/403H01M50/409H01M50/463Y02E60/10
Inventor 肖伟张开悦赵丽娜刘建国严川伟
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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