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Preparation method of high-cleanliness polyolefin diaphragm for lithium ion battery

A kind of polyolefin separator, lithium ion battery technology

Pending Publication Date: 2022-06-03
山西厚生新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a polyolefin diaphragm with high cleanliness for lithium ion batteries, which has good heat resistance stability and mechanical With the advantages of high strength and high flatness of the film surface, the lithium-ion battery prepared by using this separator has higher safety performance and better cycle performance

Method used

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  • Preparation method of high-cleanliness polyolefin diaphragm for lithium ion battery

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preparation example Construction

[0023] The preparation method of the high-cleanliness polyolefin separator of the present invention is carried out according to the following steps. During the specific implementation, the step (1) is changed, and the steps (2), (3) and (4) are all carried out according to the following steps.

[0024] (1) Melt extrusion of raw materials:

[0025] Mix a certain amount of polyolefin resin, plasticizer and silane coupling agent, and the obtained mixture is heated and melted in a twin-screw extruder; the melt is extruded through a T-die and cooled to form a cast sheet;

[0026] (2) Longitudinal stretching of sheet:

[0027] The cast sheet obtained in step (1) is longitudinally stretched by a longitudinal hot roll stretching method, and the stretching ratio is 6.5 times to obtain a diaphragm;

[0028] (3) Transverse stretch of sheet:

[0029] The diaphragm obtained in step (2) is then uniformly stretched in a chain clip type transverse direction, and the stretching ratio is 10 t...

Embodiment 1

[0033] (1) Melt extrusion of raw materials:

[0034] 10wt% polyethylene, 90wt% white oil and 0.1wt% (based on polyethylene quality) aminopropyltriethoxysilane were mixed, and the resulting mixture was heated and melted in a twin-screw extruder, and the melt passed through T The die is extruded and cooled into a cast sheet.

[0035] The other steps are implemented according to the above steps (2), (3) and (4).

Embodiment 2

[0037] (1) Melt extrusion of raw materials:

[0038] 20wt% polyethylene, 80wt% white oil and 1wt% (based on polyethylene quality) aminoethylaminopropyltrimethoxysilane were mixed, and the resulting mixture was heated and melted in a twin-screw extruder, and the melt was passed through A T-die was extruded and cooled into a cast sheet.

[0039] The other steps are implemented according to the above steps (2), (3) and (4).

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Abstract

The invention discloses a preparation method of a high-cleanliness polyolefin diaphragm for a lithium ion battery, which comprises the following four steps: melt extrusion of raw materials, longitudinal stretching of a sheet, transverse stretching of the sheet and extraction of an auxiliary agent, the silane coupling agent is agglomerated with metal and inorganic particles in the front section of production, the agglomerated particle size becomes large and cannot pass through a PF filter, and foreign matter particles in the diaphragm after cooling and casting are greatly reduced. The preparation method of the polyolefin membrane provided by the invention is low in cost and high in efficiency, the prepared polyolefin membrane has ultrahigh cleanliness, meanwhile, the membrane has the advantages of good heat-resistant stability and mechanical strength, high membrane surface flatness and the like, and a lithium ion battery prepared by using the membrane has higher safety performance and better cycle performance.

Description

technical field [0001] The invention relates to the field of preparation of diaphragms for lithium ion batteries, in particular to a preparation method of high cleanliness polyolefin diaphragms for lithium ion batteries. Background technique [0002] The separator is one of the four indispensable key materials in lithium ion batteries. Polyolefin porous membrane is widely used as a lithium battery separator. It mainly prevents the positive and negative electrodes from directly contacting and short circuit occurs, and at the same time, the ions in the electrolyte can free passage. [0003] In the production of polyolefin porous film, due to the catalyst that cannot be removed from the polyolefin raw material and the decolorizing material that has not been removed from the white oil, there are metal and inorganic foreign matter on the surface of the polyolefin porous film, and all or part of the foreign matter particles are coated on the surface of the polyolefin porous film. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/406H01M50/403H01M50/417H01M10/0525C08J9/26C08J5/18C08L23/06C08L23/12
CPCH01M50/406H01M50/403H01M50/417H01M10/0525C08J9/26C08J5/18C08J2323/06C08J2323/12Y02E60/10
Inventor 燕卫星贾培梁赵海玉翁星星
Owner 山西厚生新材料科技有限公司