Battery isolating film and method for producing the same

A battery separator and separator technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problems of polyolefin material melting, battery fire, separator damage, etc., and achieves low thermal shrinkage, good permeability, and high mechanical properties. the effect of strength

Active Publication Date: 2008-07-02
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] At present, the existing battery separator is usually based on polyolefin material. Due to the low melting point of polyolefin material, when the temperature exceeds the polyolefin material, the polyolefin material will melt and the separator will be damaged, resulting in direct contact between the positive and negative electrodes. short circuit, causing a more intense exothermic reaction, causing the battery to catch fire and explode

Method used

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  • Battery isolating film and method for producing the same
  • Battery isolating film and method for producing the same
  • Battery isolating film and method for producing the same

Examples

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preparation example Construction

[0020] The preparation method of the battery separator provided by the invention comprises forming a film from a solution containing a base material, a solvent, and a pore-forming substance, removing the pore-forming substance to obtain a porous film, and then coating the polyolefin solution on the porous film and heating it under vacuum, Cooling and phase separation, wherein the base material contains polyimide, and the holes on the base material contain a polyolefin layer.

[0021] In the present invention, there is no special limitation on the amount of polyimide, pore-forming substance, solvent and polyolefin, which is determined according to the required pore density and pore size of the battery separator. Preferably, the weight ratio of the polyimide to the pore-forming substance is 100:20-60, more preferably 100:40-50, and the weight ratio of the polyimide to the solvent is 8-15:100 , more preferably 9-12:100, the weight ratio of polyimide to polyolefin is 100:5-50, mor...

Embodiment 1

[0038] This example is used to illustrate the battery separator provided by the present invention and its preparation method.

[0039] 2500 parts by weight of pyromellitic dianhydride (PMDA, Liyang Longsha Chemical Co., Ltd.) and 2450 parts by weight of diaminodiphenyl ether (ODA, Shanghai Test Machine No. 3 Factory) are synthesized into a polyamic acid solution; The polyamic acid of weight part and the magnesium hydroxide whisker (M-HOW of Yingkou Wesike Chemical Co., Ltd.) of 1900 weight parts in the N of 49500 weight parts, N-dimethylacetamide (DMAC, Shanghai Jingwei Chemical Co., Ltd. ) and mix well. Then apply a coating film on glass to obtain a sheet with a thickness of 0.4 mm. Treat the sheet at 90°C for 5 hours to remove the solvent, program the temperature to 320°C at a rate of 6°C / min, and heat for 3 hours. , carry out imidization to obtain an inorganic hybrid polyimide film, and the thickness of the porous film is 15 microns.

[0040] The hybrid film was immersed ...

Embodiment 2

[0043] This example is used to illustrate the battery separator provided by the present invention and its preparation method.

[0044] 2500 parts by weight of biphenyltetracarboxylic dianhydride (潥yang Longsha Chemical Co., Ltd.) and 2500 parts by weight of diaminobenzophenone (Shanghai Test Machine No. 3 Factory) are synthesized into a polyamic acid solution; Polyamic acid and 2000 parts by weight of basic magnesium sulfate whiskers (Yingkou Wesker Chemical Co., Ltd.) were uniformly mixed in 42000 parts by weight of N-2-dimethylpyrrolidone (Shanghai Jingwei Chemical Co., Ltd.). Then apply a coating film on glass to obtain a sheet with a thickness of 0.4 mm. Treat the sheet at 90°C for 5 hours to remove the solvent, program the temperature to 310°C at a rate of 7°C / min, and heat for 3 hours. , carry out imidization to obtain an inorganic hybrid polyimide film, and the thickness of the porous film is 15 microns.

[0045] The hybrid film was immersed in an aqueous sulfuric acid...

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Abstract

The invention provides a battery diaphragm. The diaphragm comprises a substrate; the substrate is provided with a via, wherein, the substrate has polyimide; the channel of the via has polyolefin. The battery diaphragm obtained from the embodiment of the invention has an excellent high temperature resistance and burst can not be happened by heating to 400 DEG C; all the heat shrinkage are not more than 1.3 percent at 400 DEG C, which is far less than the heat shrinkage of 5 percent in prior art; the average diameter of pores and porosity all meet the demand of conductivity; a suitable and fine air permeability is provided; the heat shrinkage is also far less than the battery diaphragm in prior art. The battery made by the battery diaphragm provided by the invention has excellent high temperature resistance that unsafe phenomena of explosion, smoking, firing and liquid leaking can not happen even under a high temperature of 150 DEG C.

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, lithium Ion secondary batteries also have potential safety hazards. Under the conditions of high temperature, short circuit, overcharge and discharge, vibration, extrusion and impact, the temperature of the battery will rise, which will trigger chemical reactions in the internal substances of the lithium-ion battery, such as thermal decomposition of the positive electrode material, thermal decomposition of the electrolyte and Thermal decomposition of the SEI film on the negative electrode and other reactions, the products of the above reactions will react more violently with th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16C08J5/22C08J5/18C08J9/00H01M50/403H01M50/411H01M50/489
CPCY02E60/10
Inventor 李成章江林李强宫清
Owner BYD CO LTD
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