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Preparation method and application of a thermally responsive diaphragm

A thermal response and diaphragm technology, applied in structural parts, secondary battery repair/maintenance, electrical components, etc., can solve the problem of low ion conductivity of polyolefin diaphragm, thermal runaway of ternary nickel-cobalt-manganese materials, poor wettability of electrolyte, etc. problem, achieve the effect of reducing thermal runaway, fast cross-linking, and low cost

Active Publication Date: 2021-08-06
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Commercial separators are mainly polyolefin separators, which can provide sufficient mechanical strength and chemical stability at room temperature, but polyolefins are mainly composed of carbon-hydrogen bonds, which are hydrophobic, resulting in poor wettability of the electrolyte; at the same time, the ion conductivity of polyolefin separators The efficiency is low, and a large heat shrinkage will occur under high temperature conditions (PE120°C, PP 150°C), which will cause the positive and negative electrodes to contact and quickly accumulate heat, causing the battery to burn or explode, posing a great safety hazard
[0003] In particular, the thermal runaway of the existing ternary nickel-cobalt-manganese materials is an unsolved problem

Method used

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  • Preparation method and application of a thermally responsive diaphragm
  • Preparation method and application of a thermally responsive diaphragm

Examples

Experimental program
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Effect test

Embodiment 1

[0021] A method for preparing a heat-responsive diaphragm proposed by the present invention comprises the following steps:

[0022] S1. Dissolving tetramethyltetravinylcyclotetrasilane, bisvinyl-terminated polydimethylsiloxane and BPO in dichloromethane in a molar ratio of 5:4:1 to form a mixed solution;

[0023] S2. Coating the above solution on the polyethylene membrane, then putting it into a vacuum oven, and drying at 60° C. for 10 hours to obtain the thermally responsive membrane.

[0024] like figure 1 It can be seen that tetramethyltetravinylcyclotetrasilane and other double bond-containing siloxane monomers and initiators are on the surface of the porous membrane. As the temperature rises, the silane polymerizes to form a thermal insulation layer, which can effectively transfer heat. , reduce the occurrence of thermal runaway, and improve the safety of lithium-ion batteries.

Embodiment 2

[0026] A method for preparing a heat-responsive diaphragm proposed by the present invention comprises the following steps:

[0027] S1. Dissolving tetramethyltetravinylcyclotetrasilane, vinyltriethoxysilane and BPO in dichloromethane in a molar ratio of 5:4:1 to form a mixed solution;

[0028] S2. Coating the above solution on the polypropylene diaphragm, then putting it into a vacuum oven, and drying at 60° C. for 10 h to obtain the thermally responsive diaphragm.

Embodiment 3

[0030] A method for preparing a heat-responsive diaphragm proposed by the present invention comprises the following steps:

[0031] S1. Dissolving tetramethyltetravinylcyclotetrasilane, vinyltriethoxysilane and AIBN in dichloromethane in a molar ratio of 5:4:1 to form a mixed solution;

[0032] S2. Coating the polymer solution on the polyethylene diaphragm, putting it in a vacuum oven, and drying it at 60° C. for 12 hours to obtain the thermally responsive diaphragm.

[0033] Wherein, in S2, during the process of coating the mixed solution, the coating method adopted is spin coating.

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Abstract

The invention discloses a preparation method and application of a heat-responsive diaphragm. The preparation method comprises: mixing a monomer containing siloxane and an initiator into a solution, coating the surface of a porous diaphragm, and drying to obtain a heat-responsive diaphragm diaphragm. The heat-responsive diaphragm proposed by the present invention may release a large amount of heat under the conditions of battery overcharge, overload, impact, extrusion, etc. When the temperature inside the battery rises, it will trigger the polymerization of siloxane monomers to cross-link and solidify, forming The thermal insulation layer can effectively prevent the thermal runaway of the battery diaphragm and improve the safety of lithium-ion batteries.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a preparation method and application of a heat-responsive diaphragm. Background technique [0002] Lithium-ion batteries generally consist of a positive electrode, a negative electrode, an electrolyte, and a separator. The separator is a polymer material that can physically separate the positive and negative electrodes while allowing lithium ions to pass through. Commercial separators are mainly polyolefin separators, which can provide sufficient mechanical strength and chemical stability at room temperature, but polyolefins are mainly composed of carbon-hydrogen bonds, which are hydrophobic, resulting in poor wettability of the electrolyte; at the same time, the ion conductivity of polyolefin separators The efficiency is low, and a large thermal shrinkage will occur under high temperature conditions (PE120°C, PP 150°C), which will cause the positive and negative e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M50/403H01M50/414H01M50/417H01M50/449H01M10/0525H01M10/42H01M50/411
CPCH01M10/0525H01M10/4235H01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 魏锴李智陈萌
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY