A kind of composite polymer diaphragm for lithium ion battery and preparation method thereof

A composite polymer, lithium-ion battery technology, used in secondary batteries, battery pack components, circuits, etc., can solve problems such as fire and explosion, achieve rapid response, improve mechanical strength and electrochemical performance, and high absorption rate Effect

Inactive Publication Date: 2016-05-04
SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the use of a simple polymer diaphragm can absorb and fix the electrolyte solution and reduce the risk of thermal runaway of lithium-ion batteries to a certain extent, when the simple polymer diaphragm is at high temperature, it will melt and shrink, and the thermal runaway of the battery cannot be completely avoided. prone to fire and explosion

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A preparation method for a composite polymer separator for lithium-ion batteries:

[0026] Dissolve 5g polyvinylidene fluoride (molecular weight about 300,000) in 30g acetone at 40°C, and ultrasonically disperse 0.1g nano-silica (particle size about 18nm) and 1g azobisisobutyronitrile in 20g In the mixed solution of acetone and 20g butanol, slowly mix the two solutions under stirring condition, and continue to stir at 40°C for 2h, then add 10g diethyl carbonate and mix evenly to obtain a viscosity of 8000mm 2 / s mixed solution. Transfer the prepared mixed solution to the liquid storage tank of the coating machine, at a rate of 1m·min -1 Pull the aluminum foil preheated at 60°C at a high speed, and cast it to form a film. The composite polymer membrane after natural drying and setting was immersed in deionized water together with aluminum foil for 2 hours, then the composite polymer membrane was peeled off and transferred to an oven, and vacuum-dried at 60° C. for 12 h...

Embodiment 2

[0029] A preparation method for a composite polymer separator for lithium-ion batteries:

[0030] At 35°C, 2g polyvinyl chloride (molecular weight about 43,000) and 3g polystyrene (molecular weight about 85,000) were dissolved in 25g methyl ethyl ketone, and 0.3g nano-magnesium oxide (particle size about 32nm) and 1.2 1g of azodicarbonamide is ultrasonically dispersed in a mixed solution of 20g of methyl ethyl ketone and 10g of diethyl carbonate, and the two parts of the solution are slowly mixed under stirring conditions, and continue to stir at 40°C for 2h, then add 8g of butanol and mix Uniform, the viscosity is 6000mm 2 / s mixed solution. Transfer the prepared mixed solution to the liquid storage tank of the coating machine, at a rate of 1m·min -1 Pull the aluminum foil preheated at 60°C at a high speed, and cast it to form a film. The composite polymer film after natural drying and setting was immersed in deionized water together with aluminum foil for 6 hours, then th...

Embodiment 3

[0033] A preparation method for a composite polymer separator for lithium-ion batteries:

[0034] At 45°C, 5g of polyvinylidene fluoride-hexafluoropropylene (molecular weight about 625,000) was dissolved in 40g of butanone, and 0.4g of nano-silicon carbide (particle size about 28nm) and 1g of p-toluenesulfonyl hydrazide were ultrasonically Disperse in a mixed solution of 30g acetone and 20g diethyl carbonate, slowly mix the two solutions under stirring conditions, and continue stirring at 40°C for 2h, then add 4g butanol and mix evenly to obtain a viscosity of 7300mm 2 / s mixed solution. Transfer the prepared mixed solution to the liquid storage tank of the coating machine, at a rate of 1m·min -1 Pull the aluminum foil preheated at 60°C at a high speed, and cast it to form a film. The composite polymer film after natural drying and setting was immersed in deionized water together with the aluminum foil for 6 hours, then the composite polymer film was peeled off and transferr...

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Abstract

The invention relates to the technical field of a polymer diaphragm for lithium ion batteries and a preparation method thereof, and specifically discloses a composite polymer diaphragm for lithium ion batteries with excellent high-temperature safety performance and a preparation method thereof. The composite polymer is composed of high-molecular polymers, nano-inorganic fillers and high-temperature gas-generating compounds. During preparation, the high-molecular polymers, nano-inorganic fillers and high-temperature gas-generating compounds are uniformly dispersed in an organic solvent at an appropriate temperature, and the flow-through method is adopted. METHODS: Coating was used to form a membrane, and pores were formed by soaking in deionized water and phase inversion, and then vacuum-dried to obtain a composite polymer membrane. The composite polymer diaphragm prepared by the present invention reacts and releases a large amount of incombustible gas when the lithium ion battery is in a high temperature environment, causing the diaphragm to expand and isolate the positive and negative electrodes, blocking the internal current of the battery, and avoiding thermal runaway of the battery and causing fire and explosion. Improve the high temperature safety of lithium-ion batteries.

Description

technical field [0001] The invention relates to the technical field of a polymer diaphragm for lithium ion batteries and a preparation method thereof, in particular to a composite polymer diaphragm for lithium ion batteries with excellent high-temperature safety performance and a preparation method thereof. Background technique [0002] Lithium-ion batteries are high-performance secondary batteries that are widely used as power sources for notebook computers, camcorders, and mobile communication tools. Since lithium-ion batteries use flammable organic solvents as electrolyte components, when they are in extreme states such as overcharge, overdischarge, extrusion, and short circuit, it is easy to release a large amount of heat in a short time, causing thermal runaway of lithium-ion batteries, and then Battery fires and explosions occur, so the high-temperature safety of conventional lithium-ion batteries needs to be further improved. Although the use of a simple polymer diap...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M50/403H01M50/446
CPCH01M10/4235H01M10/0525H01M50/446H01M50/403Y02E60/10
Inventor 唐定国刘浩文杨汉民黄涛
Owner SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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