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Composite diaphragm for lithium battery as well as preparation method and detection method of composite diaphragm

A composite diaphragm and detection method technology, which is applied to battery pack parts, circuits, electrical components, etc., can solve the problem that it is difficult to detect the bonding layer coated on the inorganic particle layer

Active Publication Date: 2021-09-14
JIANGSU ADVANCED MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to solve the technical problem that the existing composite diaphragm detection method in the prior art is difficult to detect the bonding layer coated on the inorganic particle layer

Method used

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  • Composite diaphragm for lithium battery as well as preparation method and detection method of composite diaphragm
  • Composite diaphragm for lithium battery as well as preparation method and detection method of composite diaphragm

Examples

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preparation example Construction

[0044] A method for preparing the above-mentioned composite separator for lithium batteries, comprising:

[0045]S1. Mix inorganic particles containing inert fluorescent particles, binder, sodium carboxymethylcellulose, deionized water, and a wetting agent to form an inorganic particle layer slurry, and apply the inorganic particle layer slurry to the diaphragm substrate 10 At least one surface of the coating is dried, and an inorganic particle layer 20 is formed on the diaphragm substrate 10. In step S1, inorganic particles containing inert fluorescent particles: binder: sodium carboxymethyl cellulose: deionized water: moistening The weight ratio of the aerosol is 30:6:0.5:63:0.5.

[0046] S2. Dissolving PVDF in DMAC or NMP solvent to form a bonding layer slurry, uniformly coating the bonding layer slurry on the inorganic particle layer 20, and immersing in deionized water after coating, PVDF precipitates on the surface of the inorganic particle layer 20 Precipitate to form ...

Embodiment 1

[0062] Embodiment 1: adopt calcium tungstate (CaWO 4 ) as a fluorescent material, the excitation light is ultraviolet light, and the emitted light is 430nm blue light and 535nm green light. The inorganic particles are calcium tungstate and alumina, and the weight ratio is 5:95. The particle size D50 of calcium tungstate is 0.5 microns, and the D50 of alumina is 0.8 microns. The binder is SBR emulsion with a solid content of 25%, and the wetting agent is Tuyile DS-960E.

[0063] The manufacturing method of the inorganic particle layer 20: uniformly mix the inorganic particle layer slurry in the ratio of inorganic particle: binder: sodium carboxymethyl cellulose: deionized water: wetting agent = 30:6:0.5:63:0.5, The slurry was evenly coated on the 7 micron TNS diaphragm, and the thickness of the inorganic particle layer 20 was 2 microns after drying.

[0064] The method of making the bonding layer 30: dissolving Arkema’s LBG PVDF in DMAC to form a bonding layer slurry, the PV...

Embodiment 2

[0070] The difference between the composite diaphragm used in embodiment 2 and embodiment 1 is that the composite diaphragm of embodiment 2 is partly leak-coated with the adhesive layer 30, and the composite diaphragm used for testing is taken, and the gray value of the detection area is detected by the CCD detector 200. The gray value of the painted area is 114, and the gray value of the unpainted area is 69. The difference is 45;

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Abstract

The invention relates to the technical field of lithium batteries, in particular to a composite diaphragm for a lithium battery as well as a preparation method and a detection method of the composite diaphragm. The composite diaphragm comprises a diaphragm substrate; an inorganic particle layer which coats at least one surface of the diaphragm base material, wherein the inorganic particle layer comprises inorganic particles, and the inorganic particles contain inert fluorescent particles; and a bonding layer which coats the inorganic particle layer. According to the composite diaphragm for the lithium battery as well as the preparation method and the detection method of the composite diaphragm, whether the bonding layer is missed to be coated or not can be effectively detected, and the detection method is simple and effective.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a composite separator for lithium batteries, a preparation method thereof, and a detection method thereof. Background technique [0002] The diaphragm is one of the main components of the lithium-ion battery, which plays the role of separating the positive and negative electrodes to avoid short circuit and realize the conduction of lithium ions through the electrolyte. With the continuous promotion of lithium-ion battery applications, it is necessary to improve the safety and electrochemical performance of lithium batteries. In existing lithium batteries, the diaphragm is usually a porous PE or PP diaphragm with a thickness of 4 microns to 20 microns. However, at higher temperatures, such as over 100°C, porous PE or PP separators are prone to shrinkage, which leads to safety problems in lithium batteries that are prone to positive and negative short circuits at high te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/431H01M50/451H01M50/457H01M50/403G01N21/64
CPCH01M50/431H01M50/451H01M50/457H01M50/403G01N21/6402Y02E60/10
Inventor 张磊王晓明徐强杨浩田陈伦韦性强包慧戴静闻
Owner JIANGSU ADVANCED MATERIAL TECH CO LTD