Preparation method of gel polymer coating diaphragm and diaphragm

A gel polymer and coating technology, applied in structural parts, electrical components, battery pack components, etc., can solve the problems of difficult thickness control, strong adhesion between the coating separator and the pole piece, and unfavorable electrolyte injection. , to achieve good thickness consistency, improve cycle performance and rate performance, and facilitate injection.

Active Publication Date: 2020-04-28
武汉中兴创新材料技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, in the production process, the thickness of the gel polymer coating represented by PVDF-HFP is difficult to control when coating, and the adhesion between the prepared coating separator and the pole piece is too strong, It is not conducive to the injection of electrolyte; of course, if the adhesion between the coated separator and the pole piece is too low, it will cause other new problems

Method used

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  • Preparation method of gel polymer coating diaphragm and diaphragm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] In this example, a 20 μm polypropylene microporous membrane purchased from Shenzhen Zhongxing New Material Technology Co., Ltd. was used as the base membrane, and polyvinylidene fluoride-hexafluoropropylene gel polymer was used to coat the slurry, and dot coating The way to prepare the gel polymer coating diaphragm of this example, the specific preparation method is as follows:

[0036] (1) pulping

[0037] Add 5.0kg of polyvinylidene fluoride-hexafluoropropylene powder with an average particle size of 200nm into 37kg of acetone solution, stir and heat to 50°C, dissolve for 6h, then add 8kg of the mixed solution, stir for 0.5h, and cool to room temperature to obtain polyvinylidene fluoride-hexafluoropropylene powder. A solution of vinylidene fluoride-hexafluoropropylene in acetone, that is, a gel polymer coating slurry of polyvinylidene fluoride-hexafluoropropylene. Wherein, the mixed solution is a 1:1 solution of dimethyl carbonate and ethanol. The gel polymer coatin...

Embodiment 2

[0041] In this example, the same base film as in Example 1 is used, and the gel polymer coating slurry of polyvinylidene fluoride-hexafluoropropylene is also used, and the method of dot coating is used to prepare the gel polymer coating diaphragm of this example , The difference is that the solid content of the gel polymer coating slurry in this example is different.

[0042] The specific preparation method of the gel polymer coating diaphragm of this example is as follows:

[0043] (1) pulping

[0044] Add 6.0kg of polyvinylidene fluoride-hexafluoropropylene powder with an average particle size of 200nm into 37kg of acetone solution, stir and heat to 50°C, dissolve for 6 hours, then add 7kg of a 1:1 mixture of dimethyl carbonate and ethanol, and stir After 0.5 h, cool to room temperature to obtain polyvinylidene fluoride-hexafluoropropylene acetone solution, which is the gel polymer coating slurry of this example. The gel polymer coating slurry of this example had a solids ...

Embodiment 3

[0061] In this example, on the basis of the above tests and comparative analysis, the solid content of the gel polymer coating slurry was further tested, and the following solid content gel polymer coating slurry was specifically prepared for testing different The effect of solids content on the thickness consistency of gel polymer coated separators is as follows:

[0062] Test 1:

[0063] Add 0.5kg of polyvinylidene fluoride-hexafluoropropylene powder with an average particle size of 200nm into 40kg of acetone solution, stir and heat to 50°C, dissolve for 6h, then add 9.5kg of a 1:1 mixture of dimethyl carbonate and ethanol, Stir for 0.5 h and cool to room temperature to obtain a gel polymer coating slurry with a solid content of 1 wt%.

[0064] Test 2:

[0065] On the basis of Test 1, the amount of polyvinylidene fluoride-hexafluoropropylene powder was adjusted to 1.5 kg, the amount of acetone solution to 38.5 kg, and the mixed solution to 10 kg to obtain a gel polymer coa...

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Abstract

The invention discloses a preparation method of a gel polymer coating diaphragm and the diaphragm. The preparation method of the gel polymer coating diaphragm comprises the steps of (1) dissolving gelpolymer particles into an organic solvent, adding an additive, and uniformly stirring to prepare gel polymer coating slurry with the solid content of 1wt%-20wt%; and (2) coating at least one surfaceof a base membrane with the gel polymer coating slurry prepared in the step (1) in a dotted coating manner to form a uniformly distributed dotted coating, and drying to obtain the gel polymer coatingdiaphragm. According to the preparation method disclosed by the invention, the solid content of the gel polymer oily slurry is controlled, so that the thickness consistency of the prepared gel polymercoating diaphragm is enabled to be better. Moreover, dotted coating is adopted, so that the prepared gel polymer coating is in point contact with a pole piece, the injection of an electrolyte is convenient, and the cycle performance and the rate capability of the lithium ion battery are further improved.

Description

technical field [0001] The application relates to the field of battery diaphragms, in particular to a preparation method of a gel polymer coating diaphragm and the diaphragm. Background technique [0002] Separator is an important part of lithium-ion batteries, and its performance directly affects the capacity, cycle performance, rate performance and safety of batteries, and is one of the key technologies restricting the development of lithium-ion batteries. Due to the poor hydrophobicity and wettability of the surface of the traditionally used polyolefin microporous membrane separator, the ability to absorb and retain the electrolyte during use is poor, which affects the specific discharge capacity, cycle performance and rate performance of the battery. In order to improve the performance of the battery, gel polymer coatings such as polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) are usually coated on the surface of the separator. The unique three-dimensional networ...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 陈巧张辉姚坤刘琳刘建金
Owner 武汉中兴创新材料技术有限公司
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