Lithium-ion battery negative electrode sheet and lithium-ion battery with hard carbon and soft carbon as active materials

Abstract

The invention relates to a manufacture technology of a lithium ion battery, and particularly relates to a lithium ion battery negative electrode piece using hard carbon and soft carbon as active materials and a lithium ion battery with the negative electrode piece. The lithium ion battery negative electrode piece using hard carbon and soft carbon as the active materials comprises a metal foil current collector, a first graphitic layer, a main body functional layer and a second graphitic layer, wherein the surface of the metal foil current collector is coated with the first graphitic layer, the surface of the first graphitic layer is coated with the main body functional layer, and the surface of the main body functional layer is coated with the second graphitic layer. According to the lithium ion battery negative electrode piece using hard carbon and soft carbon as the active materials, the characteristics of a graphite material and hard carbon and soft carbon materials are fully utilized, and thus the heavy-current rate performance can be effectively improved; the lithium ion battery negative electrode piece using hard carbon and soft carbon as the active materials has the advantages of good cycle performance, high safety, high-rate charge and discharge resistance, and the like, and meets the requirement of charge performance of the lithium ion battery at a low temperature; meanwhile, a manufacture method is simple, and the lithium ion battery negative electrode piece can be produced by using existing lithium ion battery production equipment.

Description

technical field [0001] The invention relates to the manufacturing technology of a lithium ion battery, in particular to a lithium ion battery negative pole piece with hard carbon and soft carbon as active materials and a lithium ion battery with the negative pole piece. Background technique [0002] Due to its high energy density, high operating voltage, long cycle life and low self-discharge rate, lithium-ion batteries have attracted more and more attention, and their application range has gradually expanded. The positive and negative electrode materials of lithium-ion batteries are all lithium-ion intercalation compounds with a layered or tunnel structure in which lithium ions can be freely intercalated and deintercalated. At present, the anode materials in commercialized lithium-ion batteries are mainly graphite-like carbon materials. Graphite relatively well satisfies the requirements of high conductivity, large intercalation lithium capacity and high chemical stability...

AI Technical Summary

Problems solved by technology

[0007] However, hard carbon and soft carbon materials also have some defects, including: 1. The graphite system has low initial charge and discharge efficiency of the two materials; 2. The pole pieces of hard carbon and soft carbon materials have low compaction density, and the processing performance of the production process is not as good as graphite 3. The hard carbon and soft carbon system is used as the only negative electrode active material, and the peel strength of the electrode sheet is low, which may occur in the case of current collector peeling during the production process

4. The film-forming mechanism of hard carbon and soft carbon has not yet been systematically studied and analyzed

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