Preparation method of lithium-ion battery safe diaphragm material

A technology for lithium-ion batteries and diaphragm materials, which is applied in the field of preparation of safety diaphragm materials for lithium-ion batteries, can solve problems such as backward production methods, and achieve the effects of improved safety, low closed-cell temperature, and high film-breaking temperature.

Inactive Publication Date: 2016-02-24
浙江锂盾储能材料技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the technology and production methods of lithium-ion battery separators are relatively backward, and it is difficult to realize the preparation and production of lithium-ion battery separators with excellent comprehensive performance, especially the safety performance of lithium batteries, which we should pay special attention to.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A preparation method for lithium-ion battery safety diaphragm material, comprising the following steps:

[0019] Step 1, blending polyolefin and fluorine-containing polymer, melt extruding, cooling, pelletizing, melt co-extrusion temperature is 230-270°C, wherein the fluorine-containing polymer is polytetrafluoroethylene, and the polyolefin It is polyethylene, and the mass ratio of the polyolefin in the blended molten material is 3%;

[0020] Step 2, the pellets are subjected to secondary melt extrusion, cooling, and tabletting, and the secondary melting temperature is 230-270°C;

[0021] In step 3, the sheet material generated in step 2 is biaxially stretched to form a semi-finished diaphragm material with a microcrystalline structure, wherein the biaxial stretch ratio of the sheet material is 3, and the thickness of the semi-finished diaphragm material is 15 μm;

[0022] Step 4, soaking the semi-finished diaphragm material in hydrogen peroxide;

[0023] Step 5, taki...

Embodiment 2

[0025] A preparation method for lithium-ion battery safety diaphragm material, comprising the following steps:

[0026] Step 1, blending polyolefin and fluoropolymer, melt extruding, cooling, pelletizing, the melt co-extrusion temperature is 230-270°C, wherein the fluoropolymer is polyvinylidene fluoride and polyvinylidene fluoride Ethylene, the polyolefin is polypropylene, and the mass ratio of the polyolefin in the blended molten material is 10%;

[0027] Step 2, the pellets are subjected to secondary melt extrusion, cooling, and tabletting, and the secondary melting temperature is 230-270°C;

[0028] In step 3, the sheet material generated in step 2 is biaxially stretched to form a semi-finished diaphragm material with a microcrystalline structure, wherein the biaxial stretch ratio of the sheet material is 4, and the thickness of the semi-finished diaphragm material is 25 μm;

[0029] Step 4, soaking the semi-finished diaphragm material in 10% hydrogen peroxide at 30-60°C ...

Embodiment 3

[0032] A preparation method for lithium-ion battery safety diaphragm material, comprising the following steps:

[0033] Step 1, blending polyolefin and fluorine-containing polymer, melt extruding, cooling, and pelletizing, the temperature of melt co-extrusion is 230-270°C, wherein the fluorine-containing polymer is hexafluoropropylene, and the polyolefin is A combination of polyethylene, ethylene-acrylic acid copolymer, and ethylene-acrylic acid ester copolymer, the mass ratio of the polyolefin in the blended molten material is 20%;

[0034] Step 2, the pellets are subjected to secondary melt extrusion, cooling, and tabletting, and the secondary melting temperature is 230-270°C;

[0035] In step 3, the sheet material generated in step 2 is biaxially stretched to form a semi-finished diaphragm material with a microcrystalline structure, wherein the biaxial stretch ratio of the sheet material is 5, and the thickness of the semi-finished diaphragm material is 35 μm;

[0036] Ste...

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Abstract

The invention discloses a preparation method of a lithium-ion battery safe diaphragm material, comprising the following steps: step 1, blending polyolefin and a fluorine-containing polymer, performing melting extrusion, cooling and performing grain-sized dicing, wherein a melting co-extrusion temperature is 230-270 DEG C; step 2, performing secondary melting extrusion on granules, cooling and tabletting, wherein a secondary melting co-extrusion temperature is 230-270 DEG C; step 3, biaxially stretching a sheet produced in step 2, thus forming a semi-finished product of the diaphragm material with a microcrystalline structure; step 4, soaking the semi-finished product of the diaphragm material in hydrogen peroxide for treating; step 5, taking out, and vacuum-drying, thus obtaining the finished diaphragm material. By adopting the fluorine-containing polymer as a diaphragm base material, dissolution to the diaphragm material in a process that electrolyte temperature rises can be effectively resisted, and the diaphragm rupture probability is lowered; secondly, by adding polyethylene in raw materials for preparing the diaphragm material, the pore closing temperature of the diaphragm material can be effectively lowered, so that the safety of the diaphragm material is further improved.

Description

technical field [0001] The invention relates to the field of lithium ion battery diaphragm production, in particular to a method for preparing a lithium ion battery safety diaphragm material. Background technique [0002] Lithium-ion batteries are mainly composed of five materials: positive electrode material, negative electrode material, electrolyte, separator, and outer packaging material. Among them, the diaphragm material, as one of the important components of the lithium-ion battery, has been receiving much attention. The diaphragm is a microporous film placed between the positive and negative electrodes of the battery. Its main function is to separate the positive and negative electrodes of the lithium battery to avoid short circuits, and Provide free passage for lithium ions to achieve a closed loop. In addition, the lithium-ion battery separator is a polymer functional membrane material with nano-scale micropores. It is required that it does not chemically react wit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/426
CPCH01M10/0525H01M50/40H01M50/409H01M50/403H01M50/411Y02E60/10
Inventor 章结兵谢凤秀
Owner 浙江锂盾储能材料技术有限公司
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