Polymer composite lithium battery diaphragm and preparation method thereof

A battery separator and polymer technology, applied in the field of polymer composite lithium battery separator and its preparation, can solve the problems of increased thermal shrinkage of the separator, powder dropping of inorganic particles, failure of binder, etc., so as to avoid electrolyte leakage and enhance Temperature resistance, solve the effect of falling powder

Pending Publication Date: 2017-06-30
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, as the number of battery cycles increases, the binder between the inorganic particles may fail, c

Method used

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  • Polymer composite lithium battery diaphragm and preparation method thereof
  • Polymer composite lithium battery diaphragm and preparation method thereof
  • Polymer composite lithium battery diaphragm and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The high temperature resistant resin in this example is meta-aromatic polyamide (abbreviated as PMIA), the inorganic particles are made of alumina ceramic powder with purity greater than 99.99% and D50 of 0.6μm, and the solvent is N,N-dimethylacetamide (DMAc). ), the poor solvent is tripropylene glycol (TPG), the resin cosolvent is lithium chloride (LiCl), the stabilizer is propylene carbonate, and the binder is homopolyvinylidene fluoride with a molecular weight greater than 600,000.

[0031] The preparation of the coating slurry for the high-temperature resistant lithium composite battery separator in this example: firstly disperse tripropylene glycol and alumina ceramic powder with a mass ratio of 3:2, and then add them to dissolve in N,N-dimethylacetamide The mass ratio of PMIA to alumina ceramic powder in the PMIA glue is 1:3, then add an appropriate amount of LiCl, propylene carbonate and homopolyvinylidene fluoride, and mix well to obtain a slurry with a viscosity of...

Embodiment 2

[0039] The preparation of the coating slurry and the composite battery separator of this example is the same as that of Example 1. The base film is a single-layer PP film with a thickness of 12 μm prepared by Shenzhen Zhongxing Innovative Material Technology Co., Ltd.

[0040] After the coating slurry is prepared, the coating slurry is coated on one of the surfaces of the PP film by the gravure roll method. Next, the obtained film was placed in a temperature and humidity environment with a temperature of 70° C. and a relative humidity of 80-90% to preliminarily precipitate and solidify the high-temperature resistant resin; the preliminarily precipitated and solidified film used the same coagulation bath as in Example 1. Water washing and drying conditions are processed to obtain the base film with the inorganic particle coating of this example.

[0041] The polyvinylidene fluoride particles are suspended and dispersed in deionized water to prepare a polymer resin particle suspensio...

Embodiment 3

[0045] The preparation of the coating slurry and the composite battery separator of this example is the same as that of Example 1. The base film is a single-layer PP film with a thickness of 12 μm prepared by Shenzhen Zhongxing Innovative Material Technology Co., Ltd.

[0046] After the coating slurry is prepared, the coating slurry is coated on one of the surfaces of the PP film by the gravure roll method. Next, the obtained film was placed in the same temperature and humidity environment as in Example 2 for precipitation curing. Then, a 60m air-floating hot-air oven was used for drying at 70°C, and the membrane water remaining out of the box was less than 200 ppm, and the base film with the inorganic particle coating of this example was obtained.

[0047] The vinylidene fluoride-hexafluoropropylene polymer particles are suspended and dispersed in N-methylpyrrolidone to prepare a polymer resin particle suspension slurry with a viscosity of 8 cP and a slurry solid content of about ...

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Abstract

The invention discloses a polymer composite lithium battery diaphragm and a preparation method thereof. The polymer composite lithium battery diaphragm comprises a base diaphragm and inorganic particle coating on one surface or both surfaces of the base diaphragm; at least one layer of polymer resin coating is coated onto the surface of the inorganic particle coating, wherein the polymer resin coating is in a network structure formed by heat-resistant resin, and inorganic particles are uniformly embedded inside the network structure. By embedding the inorganic particles inside the heat-resistant resin network, the polymer composite lithium battery diaphragm can effectively solve the problem of particle falling and further avoids the consequent potential risks such as battery short circuit; meanwhile, the polymer resin coating can gelatinize electrolyte, so that the problem of leakage of the electrolyte can be solved, and safety performance of the battery can be enhanced.

Description

Technical field [0001] This application relates to the field of lithium ion battery separators, and in particular to a polymer composite lithium battery separator and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the characteristics of high energy density, high working voltage, no memory effect and long cycle life, and are widely used as power sources for various mobile devices. In lithium ion batteries, the main function of the separator is to separate the positive and negative electrodes of the battery and prevent the two poles from contacting and short-circuiting. The performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the performance of the battery. [0003] In order to enhance the high temperature resistance of the separator, the existing polymer composite lithium battery separator usually coats high temperature resistant inorganic particles on the surface of th...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/414H01M50/443H01M50/449
CPCH01M10/0525H01M50/403H01M50/446H01M50/449Y02E60/10
Inventor 李恒张辉王会娜樊孝红
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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