Preparation method of high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm

A technology of vinylidene fluoride and vinylidene fluoride, which is applied to the preparation of high heat-resistant vinylidene fluoride polymer mixed-coated separator, high-heat-resistant vinylidene fluoride polymer mixed-coated separator, and the field of lithium batteries, which can solve the problem of It is unfavorable for lithium ion conduction and cycle performance of lithium batteries, the effect is not significant, and the heat resistance of vinylidene fluoride polymer coating film is insufficient, etc.

Active Publication Date: 2019-12-31
NINGDE ZHUOGAO NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The water-based vinylidene fluoride polymer coating improves the adhesion between the coating film and the electrode to a certain extent, but the effect is not significant and it is easy to lose powder. The adhesion between the oil-based vinylidene fluoride polymer coating and the electrode is relatively poor Good, but it is easy to cause the diaphragm to be blocked or the air permeability to decrease, which is not conducive to the lithium ion conduction and cycle performance of the lithium battery, and the heat resistance of the vinylidene fluoride polymer coating film is insufficient

Method used

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  • Preparation method of high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm
  • Preparation method of high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm
  • Preparation method of high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm

Examples

Experimental program
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Effect test

Embodiment 1

[0066] (1) Mix 5 parts of PVDF, 2 parts of aramid and 100 parts of DMAC, stir and dissolve at 50℃ and 1500rpm for 3h, then add 20 parts of alumina, mix and stir for 1h, finally add 10 parts of polyglycerol, stir for 0.5 at 500rpm h to obtain a mixed slurry;

[0067] (2) Coat the mixed slurry on both sides of the 7μm polyethylene base film, and then pass through a pore-forming cell containing 0.1% polyoxyethylene alkylamine and 5% MMAC. The pore-forming cell temperature is 50°C, and the pore-forming time is 10s. ; Then enter the extraction tank with a temperature of 50℃ and pH=8, and the extraction time is 1min;

[0068] (3) The diaphragm after pore-making extraction is sequentially dried in a three-section oven at a temperature of 45, 55, and 50°C, and then rolled to obtain a mixed-coated diaphragm with a single-sided coating thickness of 2 μm.

[0069] The SEM topography of the final composite diaphragm surface is as follows figure 1 Shown.

[0070] by figure 1 It can be seen that c...

Embodiment 2

[0072] (1) Mix 5 parts of PVDF, 2 parts of PAI and 100 parts of NMP, stir and dissolve at 50℃ and 1500rpm for 3h, then add 20 parts of alumina, mix and stir for 1.5h, finally add 15 parts of polyglycerol, stir for 0.5 at 500rpm h to obtain a mixed slurry;

[0073] (2) Coat the mixed slurry on both sides of the 7μm polyethylene base film, and then pass through a pore-forming cell containing 0.1% polyoxyethylene alkylamine and 5% NMP. The pore-forming cell temperature is 50°C and the pore-forming time is 15 seconds. ; Then enter the extraction tank with a temperature of 50℃ and pH=8, and the extraction time is 2min;

[0074] (3) The diaphragm after pore-making extraction is sequentially dried in a three-section oven at a temperature of 45, 55, and 50°C, and then rolled to obtain a mixed-coated diaphragm with a single-sided coating thickness of 2 μm.

Embodiment 3

[0076] (1) Mix 6 parts of PVDF, 3 parts of aramid and 100 parts of DMAC, stir and dissolve at 40℃ and 1500rpm for 4h, then add 25 parts of alumina, mix and stir for 2h, finally add 10 parts of polyglycerol, stir for 0.5 at 500rpm h to obtain a mixed slurry;

[0077] (2) Coat the mixed slurry on both sides of the 7μm polyethylene base film, and then pass through a pore-forming cell containing 0.1% polyoxyethylene alkylamine and 5% MMAC. The pore-forming cell temperature is 50°C, and the pore-forming time is 20s. ; Then enter the extraction tank with a temperature of 50℃ and pH=8, and the extraction time is 2min;

[0078] 3. After the pore-forming extraction, the diaphragm is sequentially dried in a three-section oven at a temperature of 45, 55, and 50 ℃, and then rewinded to obtain a mixed-coated diaphragm with a single-sided coating thickness of 2 μm.

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Abstract

The invention relates to a preparation method of a high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm, the high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm prepared by the method and a lithium battery comprising the high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm. The prepared high-heat-resistance vinylidene fluoride polymer mixed coating diaphragm has good heat resistance and air permeability and is formed by one-time coating with simple process. The vinylidene fluoride polymer improves the adhesion between the coating andthe diaphragm and between the coating and the pole pieces, increases the liquid storage capacity of the electrolyte and improves the cycle performance of the lithium battery. The heat-resistant additive forms a heat-resistant network layer with ceramics to improve the heat shrinkage performance of the diaphragm.

Description

Technical field [0001] The invention belongs to the technical field of diaphragms, and relates to a preparation method for preparing a high-heat-resistant vinylidene fluoride polymer mixed-coated diaphragm. The high-heat-resistant vinylidene fluoride polymer mixed-coated diaphragm prepared by the method and includes the high-resistant Lithium battery with thermal vinylidene fluoride polymer mixed with separator. Background technique [0002] With the demand for high energy density of ternary and lithium iron phosphate batteries, the performance requirements of separators for lithium batteries are increasing day by day. Conventional lithium-ion battery separators currently on the market form a coating film by coating inorganic ceramics on polyolefin separators to improve the high temperature resistance and wetting properties of the polyolefin separators. [0003] Although the ceramic coating diaphragm has good high temperature resistance, the adhesion between the ceramic coating an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/446H01M50/411Y02E60/10
Inventor 杨浩田王晓明刘勇标周素霞黄云
Owner NINGDE ZHUOGAO NEW MATERIAL TECH CO LTD
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