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Battery diaphragm and its preparation method and lithium ion secondary battery containing the diaphragm

A battery separator and separator technology, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of poor heat resistance and poor mechanical strength of porous membranes, and achieve high mechanical strength, good permeability, and excellent air permeability. degree of effect

Inactive Publication Date: 2007-07-18
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 heat resistance and poor mechanical strength of porous membranes in the prior art, to provide a battery separator with good mechanical strength and good heat resistance, its preparation method and lithium ion secondary battery

Method used

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  • Battery diaphragm and its preparation method and lithium ion secondary battery containing the diaphragm
  • Battery diaphragm and its preparation method and lithium ion secondary battery containing the diaphragm
  • Battery diaphragm and its preparation method and lithium ion secondary battery containing the diaphragm

Examples

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preparation example Construction

[0032] The preparation method of the battery separator provided by the present invention includes forming a film from a solution containing a substrate, a pore-forming substance and a solvent, and removing the pore-forming substance at a temperature lower than the glass transition temperature of the substrate, wherein the substrate contains polyimide amine.

[0033] Preferably, the polyimide is polypyromellitic imide, polybiphenyl tetracarboxylic imide, polybenzophenone tetramethylimide having the structure described in the above structural formula (1), (2) or (3). One or more of imides. Since general polyimide is an insoluble substance, in order to use polyimide to obtain a battery separator with uniform quality, it is necessary to mix polyimide and pore-forming substances uniformly, so polyimide is used as a raw material to prepare When the battery separator, the present invention preferably said polypyromellitic imide is selected from polyN-alkylphenylpyromellitic imide, p...

Embodiment 1

[0055] This example is used to illustrate the battery separator provided by the present invention and its preparation method.

[0056] 5.214 grams of pyromellitic dianhydride, 4.786 grams of diaminodiphenyl ether, 10.015 grams of polystyrene containing amino groups at one end of the polymer chain (the weight-average molecular weight is 15000, purchased from Aldrich Company) and 100 grams of N-2-methyl Pyrrolidone (NMP) was stirred and mixed uniformly at room temperature to obtain a uniform solution, and then coated with an I-shaped film applicator to obtain a film with a thickness of 0.5 mm. The film was heated at 120°C for 2 hours to remove the solvent, then the temperature was programmed to 300°C at 5°C / min for imidization for 3 hours, and then the temperature was raised to 350°C for 1.5 hours, and finally cooled to 120°C while performing biaxial For stretching treatment, the stretching speed is 10 mm / min, and the stretching ratio is 2 times in the longitudinal direction (MD...

Embodiment 2

[0058] This example is used to illustrate the battery separator provided by the present invention and its preparation method.

[0059] 8.864 gram of biphenyltetracarboxylic dianhydride, 3.224 gram of p-phenylenediamine, 8.032 gram of polypropylene oxide (weight average molecular weight is 18000, purchased from Aldrich Company) and 150 gram of DMSO are stirred and mixed at room temperature Uniform, after obtaining a uniform solution, use an I-shaped film coating applicator to coat a film to obtain a film with a thickness of 0.4 mm. The film was heated at 160°C for 2 hours to remove the solvent, then programmed at 4°C / min to 270°C for imidization for 5 hours, then raised to 350°C for 1.5 hours, and finally cooled to 120°C for biaxial stretching Stretching treatment, the stretching speed is 10 mm / min, the stretching ratio is 2 times in the longitudinal direction (MD), and 2 times in the transverse direction (TD), thus obtaining the battery separator of the present invention. Amo...

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Abstract

A battery separator includes the substrate and holes distributed on it, in which, the substrate contains polyimide. The battery separator of this invention uses polyimide which is a new material bearing high temperature as substrate, so that it has excellent chemical stability, high temperature, good permeability and high mechanical strength. The lithium-ion rechargeable batteries using this invention don't appear short circuit even in 150 deg. C, thus this battery separator can be used for high-capacity and power batteries.

Description

technical field [0001] The invention relates to a battery diaphragm, a preparation method thereof and a lithium ion secondary battery containing the diaphragm. 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 safe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16C08J5/22C08J9/00H01M10/40H01M50/403H01M50/423H01M50/489
CPCY02E60/122Y02E60/10
Inventor 肖峰宫清张家鑫司雷
Owner BYD CO LTD
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