Battery separator and preparation method thereof

A technology for battery diaphragms and diaphragms, which is applied to battery pack parts, circuits, electrical components, etc., can solve the problems of poor high temperature resistance and low mechanical strength, and achieve excellent mechanical properties, excellent high temperature performance, and easy hole forming methods line effect

Active Publication Date: 2009-01-28
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the disadvantages of poor high temperature resistance and low mechanical strength of the battery separator in the prior art, and provide a battery separator with good high temperature resistance and high mechanical strength

Method used

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  • Battery separator and preparation method thereof
  • Battery separator and preparation method thereof
  • Battery separator and preparation method thereof

Examples

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preparation example Construction

[0023] The preparation method of the battery separator of the present invention comprises mixing and contacting polyvalent organic carboxylic acid anhydride or its derivatives, organic diamine, pore-forming substances and additives with a solvent to obtain a mixture, coating the mixture into a mixture layer, and removing the pore-forming substances , and then imidize the mixture layer to obtain a separator containing polyimide, and the additive is inorganic whisker and / or orthosilicate. The types of the additives have been described in detail above and will not be repeated here. Based on the total amount of the separator, the content of the polyimide may be 60-98% by weight, and the content of the additive may be 2-40% by weight. Preferably, based on the total amount of the separator, the content of the polyimide is 75-95% by weight, and the content of the additive is 5-25% by weight.

[0024] The polybasic organic carboxylic acid anhydride or its derivatives can be selected ...

Embodiment 1

[0038] This example illustrates the battery separator of the present invention and its preparation method.

[0039] With 218 parts by weight of pyromellitic dianhydride (PMDA, Liyang Longsha Chemical Co., Ltd.), 200 parts by weight of diaminodiphenyl ether (ODA, Shanghai Reagent No. 3 Factory), dioctyl phthalate of 41.8 parts by weight Esters, 13 parts by weight of orthosilicate ethyl ester and 2100 parts by weight of N-methylpyrrolidone were stirred and mixed uniformly at 25°C to obtain a mixture, which was coated on a glass sheet with an I-shaped coating film applicator to form a mixture Floor. The mixture layer was immersed in 1000 ml of water for 5 minutes, taken out, air-dried, and heated in an oven at 320° C. for 60 minutes to obtain a polyimide diaphragm. Based on the total amount of the polyimide diaphragm, polyimide The content of the amine was 97% by weight, and the content of the additive tetraethyl orthosilicate was 3% by weight. The average degree of polymerizat...

Embodiment 2

[0041] This example illustrates the battery separator of the present invention and its preparation method.

[0042] With 218 parts by weight of pyromellitic dianhydride (PMDA, Liyang Longsha Chemical Co., Ltd.), 200 parts by weight of diaminodiphenyl ether (ODA, Shanghai Reagent No. 3 Factory), 83.6 parts by weight of polyvinylpyrrolidone (Hangzhou Shenhua Technology Development Co., Ltd., K30), 22 parts by weight of calcium sulfate whiskers (Hefei Jiankun Chemical Co., Ltd., average particle diameter 20nm) and 4000 parts by weight of N-methylpyrrolidone were stirred and mixed evenly at 25°C to obtain a mixture , the mixture was coated as a mixture layer on a glass sheet with an I-shaped coating film applicator. The mixture layer was immersed in 1000 ml of water for 3 minutes, taken out, air-dried, and heated in an oven at 320° C. for 60 minutes to obtain a polyimide diaphragm. Based on the total amount of the polyimide diaphragm, polyimide The content of the amine was 95% by...

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Abstract

The invention provides a diaphragm for a battery, comprising a base material. The base material comprises through holes, wherein the base material contains polyimide and additives, and the additives are inorganic crystal whiskers and/or orthosilicate ester. The diaphragm prepared by the invention has excellent high-temperature performance, the heat shrinking property of the diaphragm is below 1.1 percent below 400 DEG C, and no cracking phenomenon occurs below 400 DEG C. The mechanical property of the diaphragm is excellent, the tensile-strength of the diaphragm is above 100 Mpa, while the tensile-strength of the diaphragm prepared by the prior art is only 90 Mpa. In addition, perforating substances used by the invention can effectively adjust the average diameter of a hole of the diaphragm within a better range of between 10 and 100 nanometers, thereby guaranteeing the smooth passing of lithium irons in the battery using the diaphragm, reducing the internal resistance of the battery, and having no short circuit.

Description

technical field [0001] The invention relates to a battery diaphragm and a preparation method thereof. Background technique [0002] With its high specific energy, high voltage, small size, light weight, and no memory, lithium-ion secondary batteries have achieved tremendous development in the past ten years and have become one of the main energy sources for communication electronic products. However, under abuse conditions, lithium-ion secondary batteries are prone to safety hazards such as smoke, fire, explosion, and even personal injury, so high-capacity and power lithium-ion batteries have not been widely used. Therefore, improving the safety of lithium-ion batteries is the key to the development of lithium-ion batteries. [0003] The battery separator plays a role in preventing the positive and negative electrodes from directly contacting the short circuit in the lithium-ion battery. In order to improve the safety of the battery, not only the battery separator is requi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16C08J5/22H01M50/403H01M50/417H01M50/446H01M50/489H01M50/494
CPCY02E60/10
Inventor 陈涛杨琼江林
Owner BYD CO LTD
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