Heat-resistant coating layer with uniform and ordered pore sizes for lithium ion battery separator and preparation method of heat-resistant coating layer

A lithium-ion battery, heat-resistant coating technology, applied in the direction of secondary batteries, battery pack components, secondary battery repair/maintenance, etc., can solve the problem of weakening the energy output, power output and cycle life of lithium-ion batteries, which is difficult To ensure the uniformity of the coating pore size, the high price of the diaphragm, etc., to achieve the effect of facilitating large-scale production, avoiding porosity and air permeability, and the preparation method is simple and easy to operate

Active Publication Date: 2017-09-22
河南惠强新能源材料科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polyolefin separators generally have poor heat resistance, and there is room for improvement
[0005] The coating method used to prepare the coating for the lithium-ion battery separator can significantly improve the heat resistance, but it is difficult to ensure the uniformity of the pore size of the coating, and the phenomenon of pore blocking is prone to occur, which weakens the energy of the lithium-ion battery to a certain extent. Output, power output and cycle life
[0006] Electrospinning process is used to prepare fibrous separators, which can obtain separators with good heat resistance and uniform pore size, but such separators are expensive and difficult to mass-produce

Method used

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  • Heat-resistant coating layer with uniform and ordered pore sizes for lithium ion battery separator and preparation method of heat-resistant coating layer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A heat-resistant coating with uniform and ordered pores is prepared by the following method:

[0036] (1) 10g weight average molecular weight Mw is 1.2×10 5 1. Add polyetherimide with a molecular weight distribution of Mw / Mn of 2 into 55g of N,N-dimethylacetamide solvent, stir and dissolve at 80°C. After the dissolution is complete, add 3g of alumina (average particle size 0.5μm), 1.3g of polyethylene glycol, and 0.6g of Tween 80, continue heating and stirring until completely dissolved, ultrasonically disperse for 45min, and cool and stand for 1h.

[0037] (2) Coat the prepared coating solution on both sides of the glass substrate and polyethylene microporous membrane respectively, place it in a constant temperature and humidity box with a temperature of 60°C and a humidity of 75% for 8 minutes, and wash with deionized water , and finally dried in hot air at 75°C to obtain a microporous coating film and a composite diaphragm respectively.

[0038] (3) The microporous...

Embodiment 2

[0044] A heat-resistant coating with uniform and ordered pores is prepared by the following method:

[0045] (1) The 10g weight average molecular weight Mw is 8×10 4 1. Add polyacrylonitrile with a molecular weight distribution Mw / Mn of 4 to 40 g of N,N-dimethylformamide, stir and dissolve at 70°C. After the dissolution is complete, add 1.5g polyvinylpyrrolidone and 0.4g Tween 60, continue heating and stirring until completely dissolved, then cool and stand for 1.5h.

[0046] (2) Coat the prepared coating solution on both sides of the glass substrate and the polyethylene microporous membrane respectively, place it in a constant temperature and humidity chamber with a temperature of 65°C and a humidity of 85% for 5 minutes, and wash with deionized water , and finally dried in hot air at 80°C to obtain a microporous coating film and a composite diaphragm respectively.

[0047] (3) The microporous coating film is separated from the glass substrate, and the pore size and its con...

Embodiment 3

[0053] A heat-resistant coating with uniform and ordered pores is prepared by the following method:

[0054] Different from Example 1, the 55g N,N-dimethylacetamide solvent in step (1) is replaced with 40g N,N-dimethylacetamide solvent, and the step (2) polyethylene microporous membrane is replaced with For the polypropylene non-woven membrane, the humidity is changed to 70%, and the storage time in the constant temperature and humidity box is changed to 10 minutes. All the other are identical with embodiment 1.

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Abstract

The invention discloses a heat-resistant coating layer with uniform and ordered pore sizes for a lithium ion battery separator and a preparation method of the heat-resistant coating layer. The heat-resistant coating layer is of a porous structure, wherein the average pore size of the heat-resistant coating layer is 600-700 nanometers, the concentrated distribution ratio of micropores with pore sizes being 500-800 nanometers is more than or equal to 60%, and the uniform and ordered pore sizes are obtained by processing for 3-30 minutes in a pore formation environment with a temperature being 30-90 DEG C and relative humidity being 60-100%. The pore sizes of the heat-resistant coating layer are uniform and ordered, and the porosity and air permeability of a composite separator can be prevented from being seriously reduced; and when the heat-resistant coating layer is applied to a lithium ion battery, the lithium ion battery can have excellent energy output, power output, safety and cycle property.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery diaphragms, in particular to a heat-resistant coating with uniform and ordered pore diameters for lithium-ion battery diaphragms and a preparation method thereof. Background technique [0002] Due to the advantages of high working voltage, high energy density, no memory effect and long cycle life, lithium-ion batteries have been widely used in portable digital devices, power tools and electric vehicles. [0003] The diaphragm is an indispensable part of the lithium-ion battery. Its main function is to isolate the positive and negative electrodes to prevent direct contact and short circuit, while allowing the ions in the electrolyte to pass freely. The performance of the separator affects the internal resistance, safety, and battery interface structure of the battery. A separator with good heat resistance can naturally guarantee the safety performance of the battery; while a separator ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/18H01M10/42H01M2/14
CPCH01M10/4235H01M50/403H01M50/411H01M50/463Y02E60/10
Inventor 黄美容朱赟王松钊蔡朝辉
Owner 河南惠强新能源材料科技股份有限公司
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