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Composite membrane and preparation method as well as battery

A composite film and base film technology, applied in the field of composite film, can solve problems such as property loss, explosion, casualties, etc., and achieve the effects of good high temperature resistance, improved safety performance, and high temperature resistance

Active Publication Date: 2015-05-27
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, lithium-ion batteries may catch fire or even explode under abuse conditions such as short circuit, overcharge, and extrusion, causing property damage and casualties
The safety issue of lithium-ion batteries has always been an obstacle restricting the larger-scale application of lithium-ion batteries
However, polyolefin microporous membranes cannot meet the safety requirements of high-capacity batteries for the heat resistance of separators.

Method used

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  • Composite membrane and preparation method as well as battery
  • Composite membrane and preparation method as well as battery
  • Composite membrane and preparation method as well as battery

Examples

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preparation example Construction

[0044] Meanwhile, the present application provides a method for preparing the above-mentioned composite membrane. The method includes: configuring a polymer solution containing the above-mentioned high-temperature polymer containing the phthalazinone biphenyl structure of formula I as a coating slurry, and applying the coating slurry to at least one of the base films On the surface, the thermodynamic state of the coating slurry is changed by physical methods, so that the coating slurry on the surface of the base membrane undergoes phase separation of polymer-rich phase and poor phase from the polymer solution, thereby forming a composite membrane with a porous layer , the above-mentioned physical methods include heating evaporation, extracting solvent in non-solvent, changing temperature, etc. That is to say, the present application uses the phase inversion method (or called phase separation) to form a porous layer with interpenetrating porous structure on the surface of the b...

Embodiment 1

[0050] The 0.5kg repeating unit is formula Ⅱ (Ar is A, R 1 , R 2 , R 3 , R 4 Both are hydrogen) poly(phthalazinyl biphenyl ether ketone) (glass transition temperature is 284°C, weight average molecular weight is 985,000, purchased from Dalian Baolimo New Material Co., Ltd.), dissolved in 9.5kg dimethyl sulfoxide, 80°C Under rapid stirring for 2 hours, a polymer solution with a mass fraction of 5% was obtained. The polymer solution with a mass fraction of 5% was used as a coating slurry, and a commercial polypropylene separator Celgard 2500 (purchased from Celgard Company) was used as a base film. Coating by dip coating, immersing the base film in the coating slurry, and then putting the base film coated with the coating slurry on both surfaces into water to make holes, taking it out, and drying at 60°C to obtain a porous layer on both sides composite film.

Embodiment 2

[0052] The 2kg repeating unit is formula Ⅱ (Ar is A, R 1 , R 2 , R 3 , R 4 Both are hydrogen) xaphthalene biphenyl polyetherketone, dissolved in 8kg N,N-dimethylacetamide, stirred rapidly at 80°C for 2 hours, to obtain a polymer solution with a mass fraction of 20%. The polymer solution with a mass fraction of 20% was used as a coating slurry, and Celgard 2500 (purchased from Celgard Company) was used as a base film. Using the dip coating method, the base film is immersed in the coating slurry, and then the two surfaces of the base film with the coating slurry applied are placed in a solution of water: ethanol = 80: 20 to make holes, taken out, and dried at 60°C A composite membrane with porous layers on both sides is obtained.

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Abstract

The invention relates to the field of a secondary battery, and provides a composite membrane, a preparation method of the composite membrane and a battery comprising the composite membrane. The composite membrane provided by the invention uses a polyolefin micro-porous membrane as a base membrane; a porous layer containing a high-temperature-resistant polymer is arranged on at least one surface of the base membrane; and the high-temperature-resistant polymer comprises a diazanaphthalene terphenyl structure shown by the formula I. The composite membrane provided by the invention uses a porous coating technology to apply the porous layer containing the high-temperature-resistant polymer to at least one surface of the base membrane. Compared with the conventional polyolefin micro-porous membrane, the composite membrane with the porous layer prepared by the invention has the advantages that the high temperature resistance can be obviously improved; and the composite membrane is used as a battery separation membrane, so that the security property of a lithium ion battery can be effectively improved.

Description

technical field [0001] The present application relates to the field of secondary batteries, in particular to a composite membrane, a preparation method thereof and a battery. Background technique [0002] In recent years, portable mobile devices such as notebook computers, mobile phones, digital cameras and video cameras have become increasingly popular, and are developing in the direction of miniaturization and thinning. At the same time, electric bicycles, hybrid electric vehicles and pure electric vehicles have also developed rapidly and have begun to be commercialized on a large scale. Correspondingly, as the power source of these tools, the requirements for battery capacity and energy density are also higher. Secondary batteries represented by lithium-ion batteries have the characteristics of high specific energy and many cycle times, and are not only widely used in various portable mobile devices, but also in large-scale electric vehicles such as electric vehicles. H...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16B32B27/08B32B27/32C08J9/36C08J9/28
CPCY02E60/10
Inventor 曹志锋张胜刚
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD