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A lithium ion battery diaphragm with a heat closing function, preparation method and application thereof

A technology for lithium ion batteries and separators, which is applied in the field of lithium ion battery separators with thermal closing function and their preparation, can solve the problem that the high temperature thermal stability and hygroscopic performance of the separator cannot meet the requirements, and the thermal stability and safety performance are not improved. The performance is not guaranteed and other problems, to achieve the effect of increasing the affinity/liquid retention performance, improving the high temperature thermal stability, and increasing the apparent density

Inactive Publication Date: 2018-12-21
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the known polyolefin separator still has the defects of poor high temperature stability, poor wettability caused by high surface polarity, and safety performance cannot be guaranteed
[0004] For example: patent CN103515562A discloses a new type of lithium-ion battery separator and its preparation method, which is prepared by wet papermaking process with polypropylene fiber, cotton fiber, dispersant, binder and retention and drainage aid as raw materials; However, due to the poor heat resistance and hygroscopicity of the raw material polypropylene fiber itself, the high temperature thermal stability and hygroscopicity of the separator prepared by it cannot meet the demand.
[0005] For example: patent CN107591512A discloses a high temperature resistant battery separator containing cellulose fiber substrate and its preparation method. The prepared separator includes cellulose fiber substrate, porous adhesive layer and inorganic coating, which can prevent battery short circuit and dendrite thorn Wear, but did not improve its thermal stability and safety performance

Method used

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  • A lithium ion battery diaphragm with a heat closing function, preparation method and application thereof
  • A lithium ion battery diaphragm with a heat closing function, preparation method and application thereof

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preparation example Construction

[0040] The present invention also provides a preparation method for the above-mentioned lithium-ion battery diaphragm, comprising the steps of:

[0041] Oxidizing polypropylene fibers to obtain hydrophilic polypropylene fibers;

[0042] Mixing the hydrophilic polypropylene fiber, xylene, acrylic acid, initiator and modifying agent to obtain modified polypropylene fiber;

[0043] Dissolving the modified polypropylene fibers and cellulose fibers in water for beating to obtain a slurry;

[0044] Dehydrating and drying the slurry to obtain a non-woven fabric film by hot pressing;

[0045] The non-woven membrane is heat-treated to obtain a lithium-ion battery separator.

[0046] The invention oxidizes the polypropylene fiber to obtain the hydrophilic polypropylene fiber.

[0047] In the present invention, the reagent for oxidation is preferably an acidic potassium permanganate solution, and the concentration of the acidic potassium permanganate solution is preferably 5% to 10%, ...

Embodiment 1

[0062] 1) Wash the polypropylene fiber with acetone, remove oil and dry it, put it in a 5% acidic potassium permanganate solution, and heat it in a water bath at 70°C for 10 minutes to obtain hydrophilic polypropylene fiber;

[0063] 2) After swelling 1Kg of hydrophilic polypropylene fiber with 5Kg of xylene and 5Kg of acrylic acid, add 0.01Kg of initiator benzoyl peroxide and 1Kg of modifier calcium carbonate for stirring to obtain modified polypropylene fiber;

[0064] 3) Soak 110g of bamboo fiber and 90g of modified polypropylene fiber in 5L of water for 6 hours, pressurize and beat the cellulose fiber to obtain a slurry with a beating degree of 60°, and then measure the moisture content of the slurry;

[0065] 4) Add 3g of dispersant polyacrylamide and 10g of binder polyhexafluoroethylene to the slurry, add water to dissolve, disperse and mix evenly;

[0066] 5) The slurry obtained in step 4 was dehydrated through a copper mesh, pressed, then dried, and hot-pressed at 120°...

Embodiment 2

[0069] 1) Wash the polypropylene fiber with acetone, remove oil and dry it, put it in an 8% acidic potassium permanganate solution, and heat it in a water bath at 80°C for 15 minutes to obtain hydrophilic polypropylene fiber;

[0070] 2) After swelling 1Kg of hydrophilic polypropylene fiber with 5Kg of xylene and 5Kg of acrylic acid, add 0.01Kg of initiator benzoyl peroxide and 1Kg of modifier calcium carbonate for stirring to obtain modified polypropylene fiber;

[0071] 3) Soak 110g of acetate fiber and 100g of modified polypropylene fiber in 5L of water for 6 hours, pressurize and beat the cellulose fiber to obtain a slurry with a beating degree of 70°, and then measure the moisture content of the slurry;

[0072] 4) Add 0.5g dispersant polyethylene oxide and 5g binder polyhexafluoroethylene to the slurry, then add water to dissolve and disperse the fibers and mix them evenly;

[0073] 5) The slurry obtained in step 4 is dehydrated through a copper mesh, pressed, then dried...

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Abstract

The invention relates to the field of lithium ion battery separators, in particular to a lithium ion battery diaphragm with a thermal closing function and a preparation method and application thereof,the diaphragm provided by the invention is a porous network crosslinking structure, comprises 40-50wt% of modified polypropylene fiber and 50-60wt% of cellulose fiber, The modified polypropylene fiber is prepared by sequentially oxidizing the polypropylene fiber and coating. The crosslinking structure is introduced into the diaphragm through in-situ micro-melting technology, the pore structure ofthe diaphragm can be improved, the mechanical strength of the diaphragm can be increased, and the thermal stability and safety performance of the diaphragm are also ensured.

Description

technical field [0001] The invention relates to the field of lithium-ion battery separators, in particular to a lithium-ion battery separator with thermal closure function, a preparation method and application thereof. Background technique [0002] Due to the advantages of high energy density, long cycle life, low self-discharge capacity, and no memory effect, lithium-ion batteries are widely used in various portable electronic devices, electric vehicles, and smart grids. Diaphragm is one of the main components of lithium-ion batteries. The performance of the diaphragm determines the interface structure, internal resistance and other properties of the lithium-ion battery, which directly affects the capacity, rate performance, cycle performance and safety performance of the battery. The direct role of the diaphragm It separates the positive and negative poles of the battery to prevent short circuit caused by contact between the two poles. In addition, it also has the channel ...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M2/14H01M10/0525H01M50/40H01M50/403H01M50/411H01M50/44
CPCH01M10/0525H01M50/403H01M50/411H01M50/44Y02E60/10
Inventor 张雄飞蒋琳琪乔露
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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