Diaphragm for battery and preparation method thereof

A separator and battery technology, applied in the field of battery separators and their preparation, can solve problems such as poor bonding performance, and achieve the effects of improving rate discharge and cycle performance, excellent bonding performance, and improving cell hardness

Active Publication Date: 2018-12-07
HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] An object of the present invention is to provide a separator for battery, comprising successively connected base film, aramid fiber coating and PVDF (Polyvinylidene difluoride, polyvinylidene fluoride) and PMMA (Polymethyl methacrylate, polymethyl methacrylate) composite coating , to alleviate the technical problem of poor bonding performance between the aramid-coated separator and the battery pole piece in the prior art

Method used

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  • Diaphragm for battery and preparation method thereof
  • Diaphragm for battery and preparation method thereof
  • Diaphragm for battery and preparation method thereof

Examples

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preparation example Construction

[0063] The preparation method of PVDF and PMMA mixed slurry comprises the following steps:

[0064] Add 25-35 parts of PVDF and 8-16 parts of dispersant to 170-190 parts of water, mix and stir for 110-130 minutes to disperse evenly, then add 110-130 parts of PMMA solution and stir for 30-40 minutes, then add 7-15 parts Thickener, 3-10 parts of defoamer and 18-25 parts of binder are stirred evenly to obtain mixed slurry of PVDF and PMMA.

[0065] Depend on figure 1 It can be seen that the particle size of PVDF pellets is 100-200nm, and the particle size of PMMA pellets is 500-600nm. PVDF and PMMA are mixed well, and the battery separator prepared after spraying has good adhesion, which is conducive to improving the adhesion with the battery pole piece. Excellent adhesion, reduce interface resistance.

[0066] Preferably, the base film includes at least one of a polypropylene base film, a polyethylene base film, a polyimide base film and a polyester non-woven fabric base film....

Embodiment 1

[0097] A separator for a battery, comprising a polyethylene base film, an aramid fiber coating and a mixed coating of PVDF and PMMA connected in sequence.

[0098] The preparation method of the separator for the battery comprises the following steps:

[0099] (a) Take 15 parts of aramid fiber, 15 parts of aluminum oxide, 12 parts of ethyl cellulose and 13 parts of dimethylacetamide, heat and stir to dissolve, the dissolution temperature is 80 ℃, and mix evenly to obtain aramid fiber slurry; The 9um polyethylene-based membrane is coated with aramid fiber slurry by oil system and subjected to extraction process, the coating thickness is 3um, and dried in an oven at 50°C for 2.5min to obtain an aramid fiber coated separator;

[0100] (b) Add 32 parts of PVDF and 10 parts of sodium polyethylene glycol alkyl aryl ether sulfonate to 175 parts of water, mix and stir for 120 minutes to make it uniformly dispersed, then add 125 parts of PMMA solution and stir for 30 minutes, then add 9...

Embodiment 2

[0102] A separator for a battery, comprising a polyethylene base film, an aramid fiber coating and a mixed coating of PVDF and PMMA connected in sequence.

[0103] The preparation method of the separator for the battery comprises the following steps:

[0104] (a) Take 25 parts of aramid fiber, 8 parts of aluminum oxide, 20 parts of dimethyl carbonate and 15 parts of N-methylpyrrolidone, heat and stir to dissolve, the dissolution temperature is 80 ℃, and mix well to obtain aramid fiber slurry; The 9um polyethylene-based membrane is coated with aramid fiber slurry by oil system and subjected to extraction process, the coating thickness is 3um, and dried in an oven at 60°C for 2 minutes to obtain an aramid fiber coated separator;

[0105](b) Add 28 parts of PVDF and 14 parts of alkylphenol polyvinyl ether to 185 parts of water, mix and stir for 120 minutes to disperse evenly, then add 118 parts of PMMA solution and stir for 30 minutes, then add 13 parts of polyethylene glycol, 5 ...

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Abstract

The invention belongs to the technical field of batteries, in particular to a separator for batteries and a preparation method thereof. The separator for battery comprises a base film, an aramid coating and a composite coating of PVDF and PMMA. On the premise of guaranteeing the permeability of the separator, the adhesive force is improved, the adhesion between the separator and the battery electrode sheet is good, the interface resistance is reduced, and the cell hardness is improved. A method for prepare a separator for a battery. The composite coating of PVDF and PMMA was obtained by spraying the mixture of PVDF and PMMA on the aramid coatings. The prepared separator has low permeability and value-added, good adhesion to the battery electrode, and can improve the rate discharge and cycle performance of the battery.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a separator for batteries and a preparation method thereof. Background technique [0002] Coated separators are becoming more and more widely used in battery applications. They are a very critical part of the battery and have a direct impact on battery safety and cost. The ions in the liquid pass freely between the positive and negative electrodes. The coating classification mainly includes: alumina coating, boehmite coating, aramid fiber coating and composite coating of alumina and boehmite. [0003] Among them, the aramid-coated diaphragm has always been the leading direction of the diaphragm market in the future. The aramid fiber coating and the base film have good adhesion, and the aramid fiber itself has good mechanical properties and high temperature resistance. But sometimes the adhesion between the aramid-coated separator and the battery pole piece is not good, which...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14
CPCH01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 徐锋袁海朝贾亚峰苏碧海
Owner HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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