Lithium-ion battery separator subjected to composite coating treatment and preparation method thereof

A lithium-ion battery and coating technology, which is applied to battery components, circuits, coatings, etc., can solve the problem of affecting battery charge and discharge performance and cycle life, inorganic particles and polymer coatings are easy to fall off, and unfavorable battery unit quality Energy density and other issues, achieve good electrolyte wettability and liquid retention, increase volume energy density, and bond tightly

Active Publication Date: 2016-12-21
深圳市鼎泰祥新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Coating inorganic particles or (and) polymers on polyolefin separators can improve the heat resistance stability and electrolyte wettability of the separators to a certain extent, but due to inorganic particles or (and) polymers and polyolefin microporous membranes The adhesion is poor, and there is a problem that the inorganic particles and the polymer coating are easy to fall off
At the same time, due to the shedding of inorganic particles and polymer coatings, the contact between the separator and the battery pole piece becomes poor, which affects the charge and discharge performance and cycle life of the battery.
Simply coating the polyolefin separator with a polymer can improve the electrolyte wettability of the separator, but the heat resistance of the separator is not significantly improved; while coating the polyolefin separator with inorganic particles alone can significantly improve the separator. Excellent heat resistance, but the inorganic particles are easy to fall off, and the density of inorganic particles is high, which is not conducive to improving the energy density per unit mass of the battery

Method used

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  • Lithium-ion battery separator subjected to composite coating treatment and preparation method thereof
  • Lithium-ion battery separator subjected to composite coating treatment and preparation method thereof
  • Lithium-ion battery separator subjected to composite coating treatment and preparation method thereof

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Embodiment 1

[0036] Polymer of the present invention and the lithium-ion battery separator of inorganic particle composite coating process, its preparation method is as follows:

[0037] a. Preparation of aramid coating solution: weigh 0.5 kg of meta-aramid fibers with a molecular weight of 50,000 to 70,000, 8.5 kg of solvent N,N-dimethylformamide, 0.3 kg of cosolvent calcium chloride, and dispersant Polyethylene oxide 0.1kg, emulsifier octadecyltrimethylammonium chloride 0.1kg, binder polyvinylpyrrolidone 0.2kg. Add the co-solvent calcium chloride into the solvent and stir until it is completely dissolved. While stirring, add the dispersant polyethylene oxide, stir at a low speed until the polyethylene oxide is completely dissolved, add meta-aramid fiber, and mix evenly to obtain meta-aramid Coating fluid.

[0038] b. Preparation of polyvinylidene fluoride coating liquid: polyvinylidene fluoride 1kg, solvent is acetone, porogen is ethanol, wherein acetone is 9.5kg, ethanol is 0.5kg. The...

Embodiment 2

[0044] Polymer of the present invention and the lithium-ion battery separator of inorganic particle composite coating process, its preparation method is as follows:

[0045] a. Preparation of aramid coating solution: weigh 0.3kg of para-aramid fiber with a molecular weight of 10,000-20,000, 7kg of solvent dimethyl sulfoxide, 0.35kg of co-solvent sodium hydroxide, and dispersant of ethylene-acrylic acid copolymer 0.1kg, emulsifier lauryltrimethylammonium chloride 0.1kg, binder vinylpyrrolidone and ethylene acetate copolymer 0.15kg. Add the co-solvent calcium chloride into the solvent and stir until it is completely dissolved. While stirring, add the dispersant polyethylene oxide, stir at a low speed until the polyethylene oxide is completely dissolved, add para-aramid fibers, and mix evenly to obtain meta-aramid Coating fluid.

[0046] b. Preparation of polyvinylidene fluoride coating solution: 1kg of vinylidene fluoride and hexafluoropropylene copolymer, solvent is N,N-dimeth...

Embodiment 3

[0052] Polymer of the present invention and the lithium-ion battery separator of inorganic particle composite coating process, its preparation method is as follows:

[0053] a. Preparation of aramid coating solution: weigh 0.32 kg of para-aramid pulp with a molecular weight of 30,000 to 40,000, 7.8 kg of solvent dimethyl sulfoxide, 0.27 kg of cosolvent sodium hydroxide, dispersant ethylene-acrylic acid Copolymer 0.14kg, emulsifier lauryltrimethylammonium chloride 0.18kg, binder vinylpyrrolidone and ethylene acetate copolymer 0.18kg. Add the co-solvent lithium chloride into the solvent and stir until completely dissolved, add the dispersant ethylene-acrylic acid copolymer while stirring, stir at a low speed until the ethylene-acrylic acid copolymer is completely dissolved, add para-aramid pulp, mix well, A para-aramid coating liquid is obtained.

[0054] b. Preparation of polyvinylidene fluoride coating liquid: polyvinylidene fluoride 1.2kg, solvent is N,N-dimethylacetamide, p...

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Abstract

The invention discloses a lithium-ion battery separator subjected to composite coating treatment and a preparation method thereof. The lithium-ion battery separator comprises a basement membrane, a polymer coating coated at one side of the basement membrane, and an inorganic particle coating coated at the other side of the basement membrane; the polymer coating is composed of an aramid coating coated on the basement membrane and a polyvinylidene fluoride coating coated on the aramid coating, and the thickness of the polymer coating is 0.3 to 5 [mu] m; and the inorganic particle coating is composed of inorganic particles of different particle sizes and a binding agent, and the thickness of the inorganic particle coating is s 0.5 to 5 [mu] m. The lithium-ion battery separator provided by the invention has the characteristics of being excellent in mechanical property and heat resistant property, having good wettability and solution preserving property to electrolyte, and excellent in cycle performance and high in safety performance.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a lithium-ion battery separator coated with polymers and inorganic particles to enhance safety performance and cycle performance and a preparation method thereof. Background technique [0002] Separator is one of the four indispensable key materials in lithium-ion batteries. It mainly plays the role of preventing short circuit caused by direct contact between positive and negative electrodes, and at the same time allows ions in the electrolyte to pass through freely. The performance of the separator determines the internal resistance of the battery and the structure of the battery interface, which directly affects the electrochemical performance and safety of the battery. A separator with excellent performance has an important impact on improving the overall performance of lithium-ion batteries. [0003] The current mainstream commercial separators are polyolefin m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16C09D177/10C09D127/16C09D7/12
CPCC08K3/22C08K2003/222C08K2003/2227C08K2201/014C08L2201/08C08L2203/206C08L2205/03C08L2205/035C09D5/18C09D127/16C09D177/10C09D7/61C09D7/63C09D7/65H01M50/403H01M50/411H01M50/431H01M50/449C08L71/02C08L39/06C08K2003/162C08K5/19C08L23/0869C08L31/04Y02E60/10
Inventor 朱赟林妙云王松钊蔡朝辉
Owner 深圳市鼎泰祥新能源科技有限公司
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