Coating composite separation membrane and preparation method thereof

A composite separator and coating technology, applied in chemical instruments and methods, layered products, synthetic resin layered products, etc., can solve problems affecting battery consistency and safety, weak electrolyte absorption and retention, and lithium battery charging Discharge efficiency and other issues, to improve absorption and retention capacity, reduce production costs, and improve safety.

Active Publication Date: 2014-04-23
SHENZHEN SENIOR TECH MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

We know that polyolefin polymers have a weak ability to absorb and retain electrolyte, which has a certain impact on the charge and discharge efficiency of lithium batteries; at the same time, the gaps and During the cycle of battery electrolyte, the free electrolyte affects the consistency and safety of the battery

Method used

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  • Coating composite separation membrane and preparation method thereof
  • Coating composite separation membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] A kind of coated composite diaphragm, comprises base film and the polymer coating layer that is coated on the base film surface, and its polymer coating layer is formed by water-based slurry coating, and in the water-based slurry, the weight proportion PVDF-HFP ( polyvinylidene fluoride-hexafluoropropylene copolymer): deionized water=100:500. First, add the adhesive PVA (polyvinyl alcohol) and the tackifier CMC into deionized water, and stir at 300r / min for 20min at room temperature until they are completely dissolved. The weight ratios of PVA and CMC are PVA:PVDF-HFP= 3:100, CMC:PVDF-HFP=1:100. Then add fluorocarbon surfactant, water-based dispersant polyoxypropylene mannitol dioleate and PVDF-HFP powder in order to the above solution, continue to stir at 300r / min for 10min, and finally stir at 5000r / min for 5min at high speed, The material configuration is complete. Among them, fluorocarbon surfactant: PVDF-HFP=0.1:100, polyoxypropylene mannitol dioleate: PVDF-HFP=0...

Embodiment 2

[0036]A kind of coated composite diaphragm, comprises base film and the polymer coating layer that is coated on the base film surface, and its polymer coating layer is formed by water-based slurry coating, and the weight proportion PVDF-HFP in the water-based slurry: Deionized water = 100:400. First, add the adhesive PVA and tackifier CMC into deionized water, stir at 300r / min for 20min at room temperature until completely dissolved, wherein the weight ratio of PVA and CMC is PVA:PVDF-HFP=3:100, CMC :PVDF-HFP=1:100. Then add fluorocarbon surfactant, water-based dispersant polyoxypropylene mannitol dioleate and PVDF-HFP powder in order to the above solution, continue to stir at 300r / min for 10min, and finally stir at 5000r / min for 5min at high speed, The material configuration is complete. Among them, fluorocarbon surfactant: PVDF-HFP=0.1:100, polyoxypropylene mannitol dioleate: PVDF-HFP=0.3:100. The weight average molecular weight of PVDF-HFP is about 140,000, and the parti...

Embodiment 3

[0038] A kind of coated composite diaphragm, comprises base film and the polymer coating layer that is coated on the base film surface, and its polymer coating layer is formed by water-based slurry coating, and the weight proportion PVDF-HFP in the water-based slurry: Deionized water = 100:500. First, add the adhesive PVA and the tackifier CMC into deionized water, stir at 300r / min for 20min at room temperature until completely dissolved, wherein the weight ratio of PVA and CMC is PVA:PVDF-HFP=5:100, CMC :PVDF-HFP=1:100. Then add fluorocarbon surfactant, water-based dispersant polyoxypropylene mannitol dioleate and PVDF-HFP powder in order to the above solution, continue to stir at 300r / min for 10min, and finally stir at 5000r / min for 5min at high speed, The material configuration is complete. Among them, fluorocarbon surfactant: PVDF-HFP=0.1:100, polyoxypropylene mannitol dioleate: PVDF-HFP=0.3:100. The weight average molecular weight of PVDF-HFP is about 140,000, and the ...

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Abstract

The present invention relates to the field of lithium battery processing, and discloses a coating composite separation membrane and a preparation method thereof. The coating composite separation membrane comprises a base film and a polymer covering layer coated on the surface of the base film, wherein the polymer covering layer comprises a water-soluble adhesive, a surfactant, a dispersing agent, a thickening agent, deionized water and polymer powder particles. The invention further discloses the preparation method for the coating composite separation membrane. The preparation method comprises: 1) preparing an aqueous slurry; 2) coating the polymer covering layer on the base film; 3) drying; and 4) winding. According to the present invention, absorption capacity and retention capacity of the separation membrane on the electrolyte are well improved, safety of the liquid state lithium battery during the use process is increased, and advantages of environmental protection and low cost are provided.

Description

technical field [0001] The invention relates to the field of lithium battery processing, in particular to a coating composite diaphragm with simple operation and accurate testing and a preparation method thereof. Background technique [0002] A lithium battery is composed of a positive electrode, a negative electrode, a separator and an electrolyte. As one of the four major materials of lithium batteries, diaphragm is an important component in lithium batteries although it does not participate in the electrochemical reaction in the battery. At the same time, diaphragm technology is also one of the key technologies restricting the development and application of lithium batteries in my country. Key properties such as battery capacity, cycle performance, and charge-discharge current density are directly related to the diaphragm. The improvement of the performance of the diaphragm plays an important role in improving the overall performance of the lithium battery. [0003] At p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16B32B27/32H01M50/403H01M50/411H01M50/449H01M50/489
CPCH01M50/403H01M50/449Y02E60/10
Inventor 吴术球王今刚陈秀峰陈良杨佳富
Owner SHENZHEN SENIOR TECH MATERIAL
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