A kind of PVDF coated lithium-ion battery diaphragm and preparation method thereof

A lithium-ion battery and separator technology, applied in battery pack components, circuits, electrical components, etc., can solve problems such as reducing the effective use of space for positive and negative materials in batteries, battery capacity and performance limitations, and affecting battery performance, etc. cracking phenomenon, improve the effective use of space, the effect of low price

Active Publication Date: 2018-05-15
CANGZHOU MINGZHU SEPARATOR TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The existing coating technology for PVDF separators of lithium-ion batteries generally adopts an oily coating process. Most of the oily coating processes use acetone as a solvent. The existing problems are: acetone is flammable, explosive, and has great harm to the human body. There are unsafe factors in the production process; at the same time, acetone is the raw material for making methamphetamine, and its use is strictly controlled by relevant departments; It has good compatibility with the diaphragm material, and the slurry will penetrate into the micropores of the base film, resulting in a large loss of air permeability, which will easily cause the diaphragm to block pores, affect the performance of the battery, and reduce the effective use space of the positive and negative materials in the battery, making the battery Capacity and performance are limited

Method used

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  • A kind of PVDF coated lithium-ion battery diaphragm and preparation method thereof
  • A kind of PVDF coated lithium-ion battery diaphragm and preparation method thereof
  • A kind of PVDF coated lithium-ion battery diaphragm and preparation method thereof

Examples

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Effect test

Embodiment 1

[0033] Example 1: Weigh 6.5 kg of vinylidene fluoride homopolymer powder, 0.3 kg of styrene-butadiene latex, 1 kg of triethyl phosphate, 0.2 kg of fluoroalkyl methoxy ether alcohol, and 792 kg of deionized water; Mix ethyl ester with deionized water, stir for 10 minutes, and heat to 50°C to make mixture 1; add vinylidene fluoride homopolymer powder to mixture 1 and grind for 1 hour to obtain mixture 2; add styrene-butadiene latex, After the fluoroalkyl methoxy ether alcohol is stirred evenly, the PVDF slurry is obtained by filtering with a 400-mesh stainless steel screen. , both sides of a polyethylene-based film with a porosity of 38%, and the coating rate is 20m / min; it is dried in a three-stage oven, and the temperatures of the ovens at each level are 55°C, 70°C, and 60°C respectively. After drying, the prepared PVDF coated Li-ion battery separator with a thickness of 20.2 μm and a coating thickness of 0.1 μm on each side.

Embodiment 2

[0034] Example 2: Weigh 7.5 kg of vinylidene fluoride and hexafluoropropylene copolymer powder, 0.3 kg of styrene-acrylic latex, 0.4 kg of pure benzene latex, 1.5 kg of triethyl phosphate, 0.15 kg of polyoxyethylene alkylamide, fatty alcohol poly 0.15 kg of oxyethylene ether, 390 kg of deionized water; mix triethyl phosphate and deionized water, stir for 30 minutes, and heat to 60°C to make mixture 1; add vinylidene fluoride and hexafluoropropylene copolymer to mixture 1 Grind the powder for 2 hours to obtain mixture 2; add styrene-acrylic latex, pure benzene latex, polyoxyethylene alkylamide, fatty alcohol polyoxyethylene ether to the above mixture 2, stir evenly, and filter through a 400-mesh stainless steel screen to obtain PVDF Slurry, the viscosity of the slurry is 10Pa s; the PVDF slurry is coated on one side of the polyvinylidene fluoride base film with a thickness of 30 μm and a porosity of 60% by narrow slot coating method, and the coating speed is 25m / min; use a thr...

Embodiment 3

[0035] Embodiment 3: Weigh 7 kg of vinylidene fluoride homopolymer powder, 0.5 kg of polyvinyl acetate, 0.8 kg of triethyl phosphate, 0.15 kg of fluoroalkyl ethoxy ether alcohol, 500 kg of deionized water; Mix ethyl ester with deionized water, stir for 20 minutes, and heat to 70°C to make mixture 1; add vinylidene fluoride homopolymer powder to mixture 1 and grind for 1.5 hours to obtain mixture 2; add polyvinyl acetate to the above mixture 2 , fluoroalkyl methoxy ether alcohol, after stirring evenly, filter with a 400-mesh stainless steel screen to obtain PVDF slurry, the slurry viscosity is 5.6Pa s; use the spray coating method to apply the PVDF slurry on On one side of a polyimide base film with a thickness of 14 μm and a porosity of 55%, the coating rate is 20m / min; three-stage ovens are used for drying, and the temperatures of the ovens at each level are 45°C, 55°C, and 50°C, respectively. After drying, a PVDF-coated lithium-ion battery separator was obtained, the thickne...

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Abstract

A PVDF-coated lithium-ion battery diaphragm and a preparation method thereof, the PVDF-coated lithium-ion battery diaphragm is composed of a base film and a coating coated on one or both sides of the base film, and the coating is formed from a slurry through It is obtained after coating and drying, the thickness of the coating is 0.1-0.5 μm, and the coating contains uniformly arranged PVDF spherical particles. The present invention abandons the traditional process of using oily substances such as acetone as a solvent for PVDF coated lithium-ion battery separators, uses water as a solvent for PVDF materials, and does not add any thickening agent to obtain low-viscosity water-based PVDF coating slurry. After the slurry is coated, an ultra-thin coating with neatly arranged PVDF particles and a relatively loose structure is obtained. While the above-mentioned ultra-thin coating can effectively bond the separator and the pole piece, it improves the hardness of the pole piece and the effective use of space for the battery, reducing the The loss of air permeability caused by thick coating is eliminated.

Description

technical field [0001] The invention relates to lithium-ion battery technology, in particular to a PVDF-coated lithium-ion battery diaphragm and a preparation method thereof, belonging to the field of battery technology. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, long cycle life, no memory effect, safety, reliability, and fast charging and discharging, and have become a research hotspot in new power supply technologies in recent years. The composition of a lithium-ion battery includes a positive electrode, a negative electrode, a separator and an electrolyte. As a barrier between the positive and negative electrodes, the separator plays a vital role in the performance of the lithium-ion battery, and its performance directly affects the capacity and cycle of the battery, especially It is an important factor affecting the safety performance of the battery, and coating the surface of the separator is an effective method to i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/426H01M50/443H01M50/491
CPCH01M50/403H01M50/491H01M50/443Y02E60/10
Inventor 赵中雷武跃邵培苓孙卫佳于中彬王庆通庄浩然
Owner CANGZHOU MINGZHU SEPARATOR TECH CO LTD
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