A kind of anti-electrolyte wrinkle lithium-ion battery diaphragm preparation method and prepared diaphragm

A lithium-ion battery and electrolyte technology, which is applied in the field of anti-electrolyte wrinkle lithium-ion battery separators and the preparation of anti-electrolyte wrinkle lithium-ion battery separators, can solve the problems of complexity and great influence on battery performance, etc.

Active Publication Date: 2021-04-13
深圳市博盛新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the improvement of the viscosity of the electrolyte involves changing various components of the electrolyte, and various components have a great influence on the performance of the battery, which is very complicated.

Method used

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  • A kind of anti-electrolyte wrinkle lithium-ion battery diaphragm preparation method and prepared diaphragm
  • A kind of anti-electrolyte wrinkle lithium-ion battery diaphragm preparation method and prepared diaphragm
  • A kind of anti-electrolyte wrinkle lithium-ion battery diaphragm preparation method and prepared diaphragm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] (1) Raw material preparation: the polypropylene raw material with a melt index of 0.8 g / 10 min, an isotacticity of 98%, and a number average molecular weight of 420,000 was used.

[0067] (2) Diaphragm preparation: the polypropylene raw material is melt-extruded by using a single-screw extruder with an aspect ratio L / D≥34, and the extrusion temperature is 230°C. The melt is coarsely filtered, precisely metered, and finely filtered, and then cast into a film through a forming die with an opening of 2mm, and cooled to 80°C by a casting roll with a diameter of 700mm to form a cast film with high crystallinity and orientation. Thin film diaphragm. The diaphragm is further wound after traction, on-line thickness measurement, surface defect treatment, edge trimming. The thickness of the diaphragm is 10-15 microns, and the thickness uniformity is ±0.1 microns. The extrusion screw is preferably a separating screw, which can separate the fully plasticized or not melt, transpor...

Embodiment 2

[0074] This embodiment adopts the polypropylene raw material that melt index is 1.0g / 10min, isotacticity is 98.5%, and number average molecular weight is 440000, and adopts the same technological step as embodiment 1, and wherein cold drawing temperature is 80 ℃, cold drawing The magnification is 1.03, the heat drawing temperature is 135°C, the heat drawing magnification is 3, and the heat setting shrinkage rate is 5%. After testing and calculation, the 5% strain stress, average pore size and porosity of the obtained lithium-ion battery separator are 520kgf / cm 2 , 41nm and 47.5%. The obtained lithium-ion battery separator was used to make a square battery, and the battery was disassembled and observed after liquid injection and formation, and the separator was flat and wrinkle-free.

Embodiment 3

[0076] This embodiment adopts the polypropylene raw material that melt index is 1.2g / 10min, isotacticity is 99%, and number average molecular weight is 410000, and adopts the same process step as embodiment 1, and wherein cold drawing temperature is 100 ℃, cold drawing The magnification is 1.07, the heat drawing temperature is 145°C, the heat drawing magnification is 5, and the heat setting shrinkage rate is 10%. After testing and calculation, the 5% strain stress, average pore size and porosity of the obtained lithium-ion battery separator are 516kgf / cm 2 , 42nm and 48%. The obtained lithium-ion battery separator was used to make a square battery, and the battery was disassembled and observed after liquid injection and formation, and the separator was flat and wrinkle-free.

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Abstract

The application provides a method for preparing an electrolyte wrinkle-resistant lithium-ion battery diaphragm, which includes the following steps: providing polypropylene raw material; melting and extruding the polypropylene raw material, casting it into a film, and cooling to obtain a diaphragm; heat-treating the diaphragm to make it The crystallization is perfect, and then cooled; the diaphragm is cold-drawn to form micro-defects, and then hot-drawn and expanded; the stretched diaphragm is heat-set; the heat-set diaphragm is naturally cooled and annealed to obtain the finished lithium-ion battery separator; Wherein, the melt index of the polypropylene raw material is 0.8-1.8g / 10min, the isotacticity is 98-99%, and the number-average molecular weight is 410000-480000; The stretching ratio is 1.03-1.07, the thermal drawing temperature is 135-145°C, and the thermal stretching ratio is 3-5. The present application also provides the electrolyte wrinkle-resistant lithium-ion battery diaphragm obtained by the preparation method.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery separators, and in particular relates to a preparation method for an electrolyte-wrinkle-resistant lithium-ion battery separator and an electrolyte-wrinkle-resistant lithium-ion battery separator prepared by the method. Background technique [0002] Lithium-ion battery separator is one of the four key main materials (positive electrode material, negative electrode material, electrolyte, separator) of lithium-ion battery. The diaphragm is placed between the positive and negative poles of the battery, which plays the role of isolating electrons in the battery and preventing the short circuit of the positive and negative poles. At the same time, it provides ion transmission channels and conducts ions during the charging and discharging process. It is the core of lithium-ion batteries. The performance of the core components has a certain impact on the internal resistance, capacity, cycle performance...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B29C48/025B29C48/09B29C71/02H01M50/403H01M50/417H01M50/491B29K23/00H01M50/406H01M50/494
CPCY02E60/10
Inventor 徐志远
Owner 深圳市博盛新材料有限公司
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