Diaphragm, preparation method and lithium ion battery comprising diaphragm

A separator and metal technology, used in the field of chemical power sources, can solve the problems of battery cycle performance, increased coating adhesion, and poor internal current consistency.

Inactive Publication Date: 2020-07-07
CHINA AVIATION LITHIUM BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this kind of separator with a water-based ceramic coating layer is accompanied by the risk of powder falling when working inside the battery. Once the ceramic material particles fall off, the thickness of the separator will be uneven, and the internal current consistency will be poor, which will affect the cycle performance of the battery.
The powder falling problem of the ceramic coating layer is due to the fact that the material of the substrate layer is PE, PP and other polymers. This polyolefin material is a non-polar material, and the force between the substrate layer and the binder and ceramic molecules Weak, so only using adhesives to increase coating adhesion has limited effect

Method used

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  • Diaphragm, preparation method and lithium ion battery comprising diaphragm

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The gas-phase alumina powder particles with an average particle size of 30nm are configured into a suspension and injected into the atomizer. After the auxiliary gas enters the atomizer to bring out the small droplets of the suspension, it enters the nozzle area, and the plasma equipment has been activated. For discharge treatment, the nozzle will conduct plasma treatment on the PP substrate layer. Among them, the temperature of the atomizer is set at 80°C, the atmosphere is air, and the flow rate is 2L / min; the plasma discharge voltage is set at 500V, the discharge treatment is performed three times, and the moving speed of the nozzle is 500mm / min, and the pretreated PP with an intermediate layer is obtained. Substrate layer. Mix the alumina powder with a D50 lower than 5 μm and pure water evenly, prepare a suspension with a solid content of 30wt%, add a dispersant (AP) with a mass of 3% of the alumina powder, stir and disperse for 10 minutes, and add the oxide The ma...

Embodiment 2

[0023] The fumed alumina powder particles with an average particle size of 10nm are configured into a suspension and injected into the atomizer. After the auxiliary gas enters the atomizer to bring out the small droplets of the suspension, it enters the nozzle area, and the plasma equipment has been activated. For discharge treatment, the nozzle will conduct plasma treatment on the PE substrate layer. Among them, the temperature of the atomizer is set at 60°C, the atmosphere is air, and the flow rate is 1 L / min. The plasma discharge voltage was set to 230V, the discharge treatment was performed once, and the moving speed of the nozzle was 100mm / min to obtain a pretreated PE substrate layer with an intermediate layer. Mix alumina powder (D10 = 0.8 μm, D50 = 3.6 μm, D90 = 9.2 μm) with pure water, prepare a suspension with a solid content of 20 wt%, and add 1% dispersant to the mass of alumina powder , stirring and dispersing for 10 minutes, adding 1% polyacrylic acid binder by ...

Embodiment 3

[0025] The fumed alumina powder particles with an average particle size of 20nm are configured into a suspension and injected into the atomizer. After the auxiliary gas enters the atomizer to bring out the small droplets of the suspension, it enters the nozzle area, and the plasma equipment has been activated. For discharge treatment, the nozzle will conduct plasma treatment on the PE substrate layer. Among them, the temperature of the atomizer is set at 40°C, the atmosphere is air, and the flow rate is 0.5 L / min. The plasma discharge voltage was set to 100V, the discharge treatment was performed twice, and the nozzle moving speed was 200mm / min to obtain a pretreated PE substrate layer. Mix the alumina powder with a D50 lower than 2 μm and pure water evenly, prepare a suspension with a solid content of 10wt%, add 0.1% dispersant by mass of alumina powder, stir and disperse for 10 minutes, add mass of alumina powder 0.1% polyacrylate binder, after stirring and dispersing for 1...

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Abstract

The invention discloses a diaphragm. The diaphragm comprises a porous base material layer, a middle layer and a ceramic coating; and the middle layer comprises metal oxide powder, the particle size ofthe metal oxide powder is smaller than the pore diameter of the porous base material layer, and the metal oxide powder is partially or completely embedded into the porous base material layer. The invention also discloses a preparation method of the diaphragm and a lithium ion battery containing the diaphragm. The diaphragm is constructed by adopting a three-layer structure of the porous base material layer, the middle layer and the ceramic coating, wherein the particle size of the metal oxide powder in the middle layer is smaller than the ion transmission aperture of the porous base materiallayer; the metal oxide powder is deposited in the pores to form the middle layer firmly combined with the base material layer, and the binding force between the ceramic coating and the base material layer is increased through the nanometer anchoring effect between the metal oxide powder with the small particle size in the middle layer and the ceramic coating coated on the surface layer of the metal oxide powder, so that powder falling is avoided.

Description

technical field [0001] The invention belongs to the field of chemical power sources, and in particular relates to a separator, its preparation method and a lithium ion battery containing it. Background technique [0002] The diaphragm with water-based ceramic coating is one of the mainstream methods adopted by domestic power battery manufacturers to improve battery safety performance. Its advantages lie in the simple and controllable coating process and low price. However, this kind of separator with a water-based ceramic coating layer is accompanied by the risk of powder falling when working inside the battery. Once the ceramic material particles fall off, the thickness of the separator will be uneven, and the internal current consistency will be poor, which will affect the cycle performance of the battery. The powder falling problem of the ceramic coating layer is due to the fact that the material of the substrate layer is PE, PP and other polymers. This polyolefin materia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14H01M10/0525
CPCH01M10/0525H01M50/431H01M50/403H01M50/449H01M50/411Y02E60/10H01M50/417H01M50/423H01M50/434H01M50/443H01M50/457
Inventor 王振宇王海文
Owner CHINA AVIATION LITHIUM BATTERY RES INST CO LTD
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