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Battery separator, lithium ion battery and preparation method thereof

A technology for lithium-ion batteries and battery diaphragms, which is applied in the fields of lithium-ion batteries and their respective preparations and battery diaphragms, can solve the problems of short-circuit heat shrinkage and poor air permeability of battery diaphragms, and improve the short-circuit rate of bare cells and finished cells Effects of short-circuiting, improving air permeability, and improving macroporous structure

Active Publication Date: 2020-06-12
SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a battery separator, a lithium-ion battery and a preparation method thereof, which are used to solve the problems of short circuit, poor thermal shrinkage, and poor air permeability of the battery separator in the prior art.

Method used

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  • Battery separator, lithium ion battery and preparation method thereof
  • Battery separator, lithium ion battery and preparation method thereof
  • Battery separator, lithium ion battery and preparation method thereof

Examples

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preparation example Construction

[0036] Such as figure 1 As shown, the present invention provides a kind of preparation method of battery diaphragm, comprises the steps:

[0037] 1) Provide a non-woven base film 11;

[0038] 2) coating the diaphragm slurry containing polyimide on at least one surface of the non-woven fabric base film 11; and

[0039] 3) Bake the structure obtained in step 2), so that the separator slurry forms porous layers 21, 22 containing polyimide, and obtains the non-woven fabric base 11 and the polyimide-containing porous layer. The porous layer 21, 22 of the battery separator.

[0040] It should be noted that the present invention provides a method for preparing a battery separator, in which a slurry containing polyimide is coated on a non-woven fabric, on the one hand, it can be used to improve the high temperature resistance of the final coated product . In addition, during the charging and discharging process of the lithium-ion battery, the polyimide-coated non-woven fabric ensu...

Embodiment 1

[0071] A) Weigh 0.1Kg of co-solvent LiCl and add it to 3Kg of the first solvent NMP and stir until it is completely dissolved. Slowly add 0.1Kg of dispersant polyethylene oxide powder with a molecular weight of 100,000-1 million while stirring, and 0.1Kg of oxidized Stir the aluminum until it is evenly dispersed, then slowly add 7Kg of polyimide solution (polyimide content is 8%) and stir evenly to prepare the polyimide slurry;

[0072] B) Take a non-woven fabric base film with a thickness of 18 μm, and use a gravure roller coating method to coat polyimide on one side of the base film at a coating speed of 12m / min, and dry it in a three-stage oven after passing through water , the oven temperatures at all levels are 50°C, 60°C, and 55°C respectively. After drying, a polyimide-coated lithium-ion battery separator can be obtained. The thickness of the polyimide-coated lithium-ion battery separator is 22 μm, the coating thickness is 4 μm.

Embodiment 2

[0074] A) Weigh 0.1Kg of co-solvent LiCl and add it to 3.5Kg of the first solvent DMAC and stir until completely dissolved, while stirring, slowly add 0.1Kg of dispersant polyethylene oxide powder with a molecular weight of 10-1 million, and 0.2Kg of Alumina is stirred until it is evenly dispersed, then slowly add 6.5Kg of polyimide solution (polyimide content is 8%) and stir evenly to obtain polyimide slurry;

[0075] B) Take a non-woven fabric base film with a thickness of 18 μm, and use a gravure roller coating method to coat polyimide on one side of the base film at a coating speed of 12m / min, and dry it in a three-stage oven after passing through water , the oven temperatures at all levels are 50°C, 60°C, and 55°C respectively. After drying, a polyimide-coated lithium-ion battery separator can be obtained. The thickness of the polyimide-coated lithium-ion battery separator is 22 μm, the coating thickness is 4 μm.

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Abstract

The invention provides a battery separator, a lithium ion battery and a preparation method thereof. The preparation of the battery separator includes: providing a non-woven fabric base film; coating at least one of the non-woven fabric base films with a separator slurry containing polyimide On the surface: baking the structure obtained in the previous step to make the separator slurry form a porous layer containing polyimide to obtain a battery separator including a non-woven base film and a porous layer containing polyimide. Through the above scheme, the battery separator of the present invention uses non-woven fabric as the base film, and a layer of polyimide is coated on its surface, which improves the macroporous structure of the non-woven fabric, improves the short circuit rate of the bare cell and the finished cell The problem of short circuit, in the production of the separator, fillers are added, which greatly improves the air permeability of the battery separator, and the polyimide is coated on the surface of the non-woven fabric, which improves the high temperature resistance and heat shrinkage of the coated product , During the charging and discharging process of the battery, the polyimide-coated non-woven fabric ensures the integrity and prevents the short circuit of the positive and negative electrodes.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to a battery diaphragm, a lithium ion battery and their respective preparation methods. Background technique [0002] Lithium-ion batteries are usually mainly composed of positive electrodes, negative electrodes, separators, electrolytes, and battery casings. In the lithium-ion battery structure, the separator is one of the key inner components. The main function of the diaphragm is to separate the positive and negative electrodes of the battery, prevent the positive and negative electrodes from being directly contacted and short circuit, and at the same time enable the electrolyte ions to pass smoothly during the charging and discharging process of the battery, forming a current, and abnormality occurs when the battery operating temperature When it rises, the migration channel of electrolyte ions is closed, and the current is cut off to ensure the safety of t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M10/42H01M50/403H01M50/417H01M50/423H01M50/429H01M50/431H01M50/449H01M50/489
CPCH01M10/0525H01M10/4235H01M50/446H01M50/403H01M50/449H01M50/431H01M50/429H01M50/417H01M50/489Y02E60/10H01M50/44
Inventor 程跃王连杰陈永乐王治学
Owner SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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