Coating-modified anode material of lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a coating-modified anode material of a lithium ion battery. The coating-modified anode material comprises a core layer and a shell layer which is coated outside the core layer, wherein the core layer is a graphite or silicon material; the shell layer is thermosetting resin with the decomposing temperature higher than 180 DEG C, and the mass of the shell layer is 1-10% of the total mass of the anode material. Compared with the prior art, the coating-modified anode material has the advantages that the surface of the core layer material is coated with the thermosetting resin, so that the resistance of the anode material can be improved, after a short circuit occurs between a cathode current collector and an anode diaphragm, the current can be reduced, and heat can be reduced; the anode material has a certain flame-retardant effect and low heat conductivity, and heat insulation can be carried out, so that the thermal runway problem of the battery can be solved well, and the safety performance of the battery can be improved; moreover, the thermosetting resin has holes capable of enabling lithium ions to pass, so that the electrochemical performance of the battery cannot be affected greatly; besides, because the shell layer has great mechanical intensity, the volume expansion of the core layer material can be inhibited.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a coated and modified lithium ion battery anode material. Background technique [0002] At present, lithium-ion batteries generally include cathode sheets, anode sheets, separators, and electrolytes. The electrolytes generally use flammable organic solvents, such as ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate. Therefore, people The safety requirements for batteries are very high to avoid risks such as explosion and combustion. Therefore, general battery manufacturers need to sample and test the safety of the battery before the battery is produced. If the battery can pass a series of safety tests such as short circuit test, nail penetration test, overcharge test, high temperature test, etc., the safety performance can be considered to be up to standard. . [0003] Studies have shown that when a short circuit occurs between the cath...

AI Technical Summary

Problems solved by technology

This is because the resistance of the anode diaphragm is significantly smaller than that of the cathode diaphragm. When the cathode current collector and the anode diaphragm are short-circuited, the amount of current passing through the anode diaphragm is relatively large, resulting in a large amount of heat generation, resulting in thermal runaway, which is very It is easy to cause combustion, so that the battery cannot pass the safety test and cannot be used

[0004] In order to solve this problem, CN101055925A provides a kind of technical scheme covering metal oxide on the surface of the anode piece, although this scheme can improve the internal resistance of the surface of the anode piece and reduce the thermal conductivity of the anode piece to a certain extent, but the aluminum oxide Such oxides still have high thermal conductivity, which cannot solve the thermal runaway and combustion problems of the battery well. Moreover, since the metal oxide itself does not have good mechanical properties and the metal oxide is only coated on the anode sheet Surface, therefore, does not act as a good inhibitor when the anode active material (especially silicon) expands during cycling

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