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Functional diaphragm with safety performance, and preparation method and application thereof

A technology with safety performance and function, applied in the field of lithium-ion batteries, can solve problems such as increasing the risk and degree of harm of battery short circuit, thermal runaway of positive and negative electrodes, shrinkage and deformation of diaphragm, etc., to reduce the risk of thermal runaway, reduce internal short circuit, The effect of improving safety performance

Pending Publication Date: 2021-12-03
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The diaphragm is a barrier for the safety function inside the lithium-ion battery. The material of the diaphragm commonly used at present is polyolefin material, which has a low melting point, generally <150°C, and has poor high-temperature heat resistance. When the internal temperature of the battery is close to the diaphragm When the heat deflection temperature is higher, the diaphragm will shrink and deform, which will cause direct contact between the positive and negative electrodes and cause internal thermal runaway.
With the improvement of battery energy density, the separator used in the battery is gradually thinner, but this will greatly increase the risk and degree of harm of short circuits in the battery

Method used

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  • Functional diaphragm with safety performance, and preparation method and application thereof
  • Functional diaphragm with safety performance, and preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0037] This embodiment provides a functional diaphragm with safety performance, which is to apply a low-melting point polyethylene emulsion on one side surface of a PET substrate (base film) with a thickness of 12 μm and then bake it by using a slot extrusion coating process. Dried;

[0038] Wherein, the particle size D50 of the low melting point polyethylene emulsion is 0.5 μm, Dmax is 2 μm, the viscosity is 2000 mPa·s, and the solid content is 30%;

[0039] The melting range of the low melting point polyethylene is 95-115°C;

[0040] The coating speed is 30m / min;

[0041] The thickness of the obtained low-melting-point polyethylene coating after coating was 3 μm.

Embodiment 2

[0043] This embodiment provides a functional diaphragm with safety performance, which is to apply a low-melting point polyethylene emulsion to one side surface of a PI matrix (base film) with a thickness of 12 μm and then bake Dried;

[0044] Wherein, the particle size D50 of the low melting point polyethylene emulsion is 0.6 μm, Dmax is 2.5 μm, the viscosity is 3500 mPa·s, and the solid content is 40%;

[0045]The melting range of the low melting point polyethylene is 105-120°C;

[0046] The coating speed is 40m / min;

[0047] The thickness of the obtained low-melting-point polyethylene coating after coating was 2 μm.

Embodiment 3

[0049] This embodiment provides a functional diaphragm with safety performance, which is to apply a low-melting point polyethylene emulsion to one side surface of an aramid fiber substrate (base film) with a thickness of 12 μm and then apply a slot-type extrusion coating process. made by drying

[0050] Wherein, the particle size D50 of the low melting point polyethylene emulsion is 0.7 μm, Dmax is 3 μm, the viscosity is 5000 mPa·s, and the solid content is 50%;

[0051] The melting range of the low melting point polyethylene is 100-120°C;

[0052] The coating speed is 50m / min;

[0053] The thickness of the obtained low-melting-point polyethylene coating after coating was 3 μm.

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Abstract

The invention provides a functional diaphragm with safety performance, and a preparation method and application thereof. The functional diaphragm with safety performance comprises a base body and a low-melting-point high polymer material coating coated on one side surface or two side surfaces of the base body, wherein the base body is made of a high-melting-point high polymer material. According to the functional diaphragm with the safety performance, the hole closing temperature is lower than 120 DEG C, the diaphragm breaking temperature is higher than 300 DEG C, the safe use temperature interval is higher than 180 DEG C or so, the safety performance of a lithium ion battery can be improved to a great extent, and the risk of thermal runaway of the lithium ion battery is reduced.

Description

technical field [0001] The invention relates to a functional diaphragm with safety performance, a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. Background technique [0002] The diaphragm is a barrier for the safety function inside the lithium-ion battery. The material of the diaphragm commonly used at present is polyolefin material, which has a low melting point, generally <150°C, and has poor high-temperature heat resistance. When the internal temperature of the battery is close to the diaphragm When the thermal deformation temperature is higher, the diaphragm will shrink and deform, which will cause direct contact between the positive and negative electrodes and cause internal thermal runaway. With the improvement of battery energy density, the separator used in the battery is gradually thinned, but this will greatly increase the risk and degree of harm of short circuits in the battery. [0003] Regulating the...

Claims

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Application Information

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IPC IPC(8): H01M50/449H01M50/489H01M50/403H01M10/0525
CPCH01M50/449H01M50/489H01M50/403H01M10/0525Y02E60/10
Inventor 陈萌刘中奎徐立洋周保福宫璐杨茂萍
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY