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Method for preparing lithium ion battery membrane

A technology for lithium ion batteries and separators, which is applied in the field of preparation of lithium ion battery separators, can solve the problems of decreased composite fastness, interface debonding, poor compatibility, etc.

Active Publication Date: 2017-03-22
SHENZHEN SENIOR TECH MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, PP and PE are semi-crystalline thermoplastic materials. The compatibility between the two is poor, and the rheological behavior and crystallization rate are also very different. If the temperature drops, the product is prone to delamination; if the temperature is too high, the formed PE micropores will be closed, which will affect the air permeability of the product.

Method used

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  • Method for preparing lithium ion battery membrane
  • Method for preparing lithium ion battery membrane
  • Method for preparing lithium ion battery membrane

Examples

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preparation example Construction

[0020] The embodiment of the present invention discloses a preparation method of a lithium-ion battery diaphragm, which includes the following steps: mixing polypropylene, the first alloy material and the first auxiliary additive, stirring, and then adding to the first extruder to melt and plasticize, to obtain The first melt; polyethylene, the second alloy material and the second auxiliary additive are mixed, stirred, and then added to the second extruder for melting and plasticizing to obtain the second melt; the first melt and the second The melt die is extruded, and an intermediate film is formed after casting treatment. The intermediate film uses the second melt as the middle layer and the first melt as the surface layer; the intermediate film is annealed under slight tension. Stretched to form a lithium-ion battery separator.

[0021] The lithium ion battery prepared by the present invention is a three-layer PP / PE / PP microporous membrane, the thickness is preferably 5-40...

Embodiment 1

[0035] This example provides a high-performance lithium-ion battery microporous diaphragm, the main raw material of which is polypropylene, polyethylene, alloy material (PP / PE mass percentage is 7:3), and the auxiliary additive is antioxidant 1010 (four [ Methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester), the thickness of the microporous membrane is 16 μm, and the porosity is 37%. The content of main resin polypropylene and polyethylene is 90%, wherein the mass percentage of polypropylene: polyethylene is 4:3, the mass percentage of alloy material is calculated as 5%, and the content of antioxidant is calculated as 5% by mass percentage.

[0036] The method for preparing the described microporous membrane comprises the steps of:

[0037] 1. Stir the main polypropylene, 1 / 2 weight alloy material and 1 / 2 weight auxiliary additives through a high-speed mixing mixer under certain conditions, the stirring speed is 3000rpm, and the stirring time is 30mi...

Embodiment 2

[0046] This example provides a high-performance lithium-ion battery microporous diaphragm, the main raw material of which is polypropylene, polyethylene, alloy material (PP / PE mass percentage is 6:4), and the auxiliary additive is antioxidant 1010 (four [ Methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester), the thickness of the microporous membrane is 16 μm, and the porosity is 37%. The content of polypropylene and polyethylene in the main resin is 85%, wherein the mass percentage of polypropylene: polyethylene is 4:3, the mass percentage of alloy material is calculated as 10%, and the content of antioxidant is calculated as 5% by mass percentage.

[0047] The method for preparing a microporous membrane for a high-performance lithium-ion battery is basically the same as in Example 1, except that in the sixth annealing process, the annealing temperature is changed to 110°C.

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Abstract

The invention provides a method for preparing a lithium ion battery membrane. Body PP and PE resin are fused at a high temperature in a melt extrusion and stretch mode, the problem of composition firmness can be solved, and as the two kinds of resin is compounded prior to the extension slotting operation, the problem of PE hole closure at the high temperature does not need to be worried; and by adding an alloy, the problem that the crystal structure of the interface is broken by the interinfiltration of the interface PP and PE materials fused at the high temperature, resulting in that a micropore cannot be formed in the interface layer due to the over deep fusion interface. Therefore, the microporous membrane for the lithium ion battery prepared by the method provided by the invention has the advantages of high performance, high puncture strength, low closing temperature and high film breaking temperature.

Description

technical field [0001] The invention relates to the technical field of diaphragms, in particular to a method for preparing a lithium-ion battery diaphragm. Background technique [0002] Lithium-ion batteries are composed of positive and negative electrode materials, electrolyte, separator and battery case. As the "third pole" of the battery, the separator is one of the key inner components in a lithium-ion battery. Lithium battery separator is one of the core components of lithium-ion batteries, accounting for about 20-30% of the cost of the entire lithium battery. Its performance has a very important impact on the overall performance of lithium batteries, and is a key technology that restricts the development of lithium batteries one. With the continuous expansion of the application field of lithium batteries and the deepening influence of lithium battery products in people's lives, people's requirements for the performance of lithium batteries are also getting higher and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/446H01M50/489H01M50/491
CPCH01M50/409H01M50/403Y02E60/10
Inventor 杨雪梅陈勇高东波陈秀峰
Owner SHENZHEN SENIOR TECH MATERIAL
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