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Safety diaphragm, preparation method thereof and lithium ion battery

A safety diaphragm and safety technology, applied in secondary batteries, battery pack components, circuits, etc., can solve problems such as battery short-circuit fire, and achieve the effects of avoiding short-circuit fire, improving heat resistance, and reducing temperature

Pending Publication Date: 2021-11-23
HUIZHOU LIWINON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] Lithium-ion batteries are widely used in 3C digital products and electric vehicles because of their high energy density, good rate performance, and environmental protection. Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, diaphragms, electrolytes, and aluminum-plastic films. Among them, the diaphragm plays an important role in conducting ions, isolating the positive and negative electrodes, and preventing short circuit in the lithium-ion battery; most of the commercially used lithium-ion battery diaphragms are polyolefin materials, and severe shrinkage will occur when the temperature is higher than 130 ° C. Causes the positive and negative poles of the battery to contact and cause the risk of short circuit and fire, so there is an urgent need for a technical method to solve the above problems

Method used

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  • Safety diaphragm, preparation method thereof and lithium ion battery
  • Safety diaphragm, preparation method thereof and lithium ion battery

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preparation example Construction

[0028] 2. A method for preparing a safety diaphragm, comprising the following steps:

[0029] Step (A): adding the polymer and the hot-melt additive into the organic solvent, stirring and mixing to form a mixed glue;

[0030] Step (B): coating the mixed glue solution on at least one side of the base film, washing with water, and drying to form a safety coating to obtain a safety diaphragm.

[0031] The hot-melt additive of the present invention is a substance that melts at a high temperature of 90 to 130°C, so it can melt and absorb part of the heat under high temperature conditions, and block the micropores of the base film after melting, thereby reducing the transmission of ions, which can Prevent heat from accumulating and rising in a certain area, so as to effectively control thermal runaway.

[0032] The present invention uses an organic solvent to form an organic solvent system after mixing polymers and hot-melt additives, and the prepared diaphragm has good adhesion, g...

Embodiment 1

[0040] A method for preparing a safety diaphragm, comprising the steps of:

[0041] Step (A): adding the polymer and the hot-melt additive into the organic solvent, stirring and mixing to form a mixed glue;

[0042] Step (B): adding the inorganic filler into the mixed glue and stirring to form a coating slurry;

[0043] Step (C): coating the coating slurry on both sides of the base film, washing with water, and drying to form a safety coating to obtain a safety diaphragm.

[0044] Wherein, the weight-number ratio of the polymer, the hot-melt additive and the inorganic filler is 70:25:55.

[0045] Wherein, the inorganic filler is alumina.

[0046] Wherein, the polymer is polytetrafluoroethylene.

[0047] Wherein, the hot-melt additive is low molecular weight polyethylene.

[0048] Wherein, the base film is a polypropylene base film.

[0049] Wherein, the organic solvent is ethanol.

[0050] A safety diaphragm, a base film and safety coatings arranged on both sides of the ...

Embodiment 2

[0052] The difference with embodiment 1 is:

[0053] The ratio of parts by weight of the polymer, the hot-melt additive and the inorganic filler is 65:5:30.

[0054] The rest are the same as in Embodiment 1, and will not be repeated here.

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a safety diaphragm and a preparation method thereof and a lithium ion battery. The safety diaphragm comprises a base diaphragm and a safety coating arranged on at least one side face of the base diaphragm; the safety coating comprises a hot melting additive, and the hot melting additive is used for absorbing heat and melting to block membrane holes of the base diaphragm. The safe diaphragm is provided with the safe coating which can absorb heat, reduce the temperature of the base diaphragm and improve the heat resistance of the base diaphragm in a high-temperature environment, and can melt and block diaphragm holes of the base diaphragm, so short-circuit fire breakout of a battery cell is avoided.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a safety diaphragm, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products and electric vehicles because of their high energy density, good rate performance, and environmental protection. Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, diaphragms, electrolytes, and aluminum-plastic films. Among them, the diaphragm plays an important role in conducting ions, isolating the positive and negative electrodes, and preventing short circuit in the lithium-ion battery; most of the commercially used lithium-ion battery diaphragms are polyolefin materials, and severe shrinkage will occur when the temperature is higher than 130 ° C. It causes the positive and negative poles of the battery to contact and cause the risk of short circuit a...

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 邓豪马斌陈杰
Owner HUIZHOU LIWINON NEW ENERGY TECH CO LTD