A kind of preparation method of lithium-ion battery diaphragm

A lithium-ion battery and separator technology, applied in the field of preparation of lithium-ion battery separators, can solve the problems of decreased composite fastness, interface debonding, and impact on product air permeability.

Active Publication Date: 2019-11-22
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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  • A kind of preparation method of lithium-ion battery diaphragm
  • A kind of preparation method of lithium-ion battery diaphragm
  • A kind of preparation method of lithium-ion battery diaphragm

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 preparation method of a lithium-ion battery diaphragm. The main body PP and PE resin are fused at high temperature by means of melt extrusion and stretching, which can solve the problem of composite fastness. Compositing, there is no need to worry about the problem of PE closed cells at high temperatures; by adding alloy materials, the interpenetration of PP and PE materials at the high-temperature fusion interface can be effectively solved, and the crystal structure of the interface will be damaged, and the excessively deep fusion interface will cause the interface layer to fail. The problem of micropore formation. Therefore, the microporous diaphragm for lithium ion battery that can be prepared by the present invention has the characteristics of high performance, high puncture strength, low shutdown temperature, and high membrane rupture 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 Patents(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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