Lithium ion battery separation membrane and preparation method thereof, and lithium ion battery

A technology of lithium ion battery and separator, applied in the field of lithium ion battery separator and its preparation, can solve the problems of not really improving the stability of the composite separator, failing to improve the thermal shrinkage of the separator, low tensile strength and puncture strength, etc. Achieve the effects of low high temperature thermal shrinkage, good high temperature mechanical strength and simple preparation process

Inactive Publication Date: 2018-03-13
BYD CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this product cannot really improve the stability of the composite membrane at higher temperatures, mainly because the high molecular polymer it uses is one or both of PMMA, PAN, PVDF and P(VDF-HFP). More than one mixture, among which, the melting point of PMMA is 130-140°C, the glass transition temperature of polyacrylonitrile PAN is about 90°C, the carbonization temperature is about 200°C, and the melting point of PVDF is 170°C. (>180°C) The effect of thermal shrin

Method used

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  • Lithium ion battery separation membrane and preparation method thereof, and lithium ion battery
  • Lithium ion battery separation membrane and preparation method thereof, and lithium ion battery
  • Lithium ion battery separation membrane and preparation method thereof, and lithium ion battery

Examples

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Example Embodiment

[0024] According to a preferred embodiment of the present invention, the heat-resistant layer is formed by electrospinning a spinning solution containing a high-temperature resistant polymer and inorganic nanoparticles.

[0025] The present invention does not specifically limit the type of the high temperature resistant polymer, and it can be various existing polymers with good high temperature resistance. Preferably, the melting point of the high temperature resistant polymer is not lower than 180°C, more Preferably it is 200-600°C. Examples of the high temperature resistant polymer include, but are not limited to: polyetherimide (PEI), polyimide (PI), polyetheretherketone (PEEK), polyethersulfone (PES), polyamideimide At least one of (PAI), polyamic acid (PAA), and polyvinylpyrrolidone (PVP). Among them, polyether ether ketone (PEEK) includes copolyether ether ketone (CoPEEK) and modified (homopoly) polyether ether ketone.

[0026] According to the lithium ion battery separator...

Example Embodiment

[0141] Example 1 (Porous base film (PE base film)-lithium ion battery separator with two layers of heat-resistant layer)

[0142] This embodiment is used to illustrate the lithium ion battery separator provided by the present invention and the preparation method thereof.

[0143] Polyetherimide (PEI, commercially available from SABIC Innovative Plastics (Shanghai) Co., Ltd., melting point 370-410℃, the same below) and Al 2 O 3 The particles (the average particle size is 200nm, the same below) are added to N,N-dimethylpyrrolidone (NMP) at a weight ratio of 10:1 (ie 100:10), and then magnetically stirred in a 70°C water bath to form a concentration It is 15wt% spinning solution.

[0144] Wrap one side of the PE base film (purchased from Japan SK company, brand name BD1201, thickness of 11μm, the same below) on one side of the drum (collecting device), and electrospun with needles on the surface of the PE base film Method for electrospinning the above spinning solution. Adjust the ele...

Example Embodiment

[0150] Example 2 (Heat-resistant layer-porous base film (ceramic separator)-lithium ion battery separator with three-layer structure of heat-resistant layer)

[0151] This embodiment is used to illustrate the lithium ion battery separator provided by the present invention and the preparation method thereof.

[0152] (1) Preparation of ceramic diaphragm:

[0153] 2kg Al 2 O 3 Granules (average particle size 400nm), 0.01kg sodium polyacrylate (number average molecular weight is 9000, purchased from Guangzhou Yuanchang Trading Co., Ltd.), 0.024kg sodium carboxymethyl cellulose (1% by weight aqueous solution viscosity is 2500-3000mPa ·S, purchased from Xinxiang City Heluolida Power Material Co., Ltd., brand name BTT-3000) mixed with water evenly to make Al 2 O 3 The solid content of the mixture is 30% by weight, the mixture is stirred at 6000 rpm for 1.5 hours, then 0.02 kg of 3-glycidoxypropyltrimethoxysilane is added and the mixture is stirred for 1.5 hours, and then 0.1 kg of polyacry...

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Abstract

The invention relates to the field of lithium ion batteries, and discloses a lithium ion battery separation membrane and a preparation method thereof, and a lithium ion battery. The lithium ion battery separation membrane comprises a porous base film and a heat-resistant layer covering the surface of at least one side of the porous base film, wherein the heat-resistant layer contains a high-temperature-resistant polymer and inorganic nanoparticles, and the heat-resistant layer has a fiber network structure. The lithium ion battery separation membrane of the present invention has advantages ofhigh lithium ion conductivity, improved heat resistance and improved mechanical strength at the high temperature.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery diaphragm, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries are mainly composed of positive / negative electrode materials, electrolytes, separators and battery casing packaging materials. The separator is an important part of the lithium-ion battery. It is used to separate the positive and negative electrodes, prevent the internal short circuit of the battery, allow the electrolyte ions to pass freely, and complete the electrochemical charge and discharge process. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the rate performance, cycle performance, and safety performance (high temperature resistance) of the battery. A separator with excellent performance plays an important role in improving the overall performan...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/451H01M50/454H01M50/457H01M50/489H01M50/491
CPCH01M10/0525H01M50/403H01M50/44H01M50/451H01M50/491H01M50/489H01M50/417H01M50/457H01M10/052Y02E60/10H01M50/446H01M50/461H01M50/454H01M50/431H01M50/443H01M50/434C08J5/005B32B2305/30B32B2307/306Y02P70/50
Inventor 胡家玲刘荣华单军何龙
Owner BYD CO LTD
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