Negative electrode sheet, secondary battery, battery module, battery pack, and electric device

By designing a second film structure with a tilted edge on the negative electrode sheet, and combining carbon-based and silicon-based active materials, the problem of lithium plating at the edge of the negative electrode sheet is solved, extending the cycle life of the secondary battery and improving its safety.

CN116979020BActive Publication Date: 2026-07-14CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
Filing Date
2022-04-22
Publication Date
2026-07-14

AI Technical Summary

Technical Problem

Wavy edges on the negative electrode sheet can lead to lithium plating, resulting in shortened cycle life and reduced safety of the secondary battery.

Method used

A negative electrode structure is designed, including a negative current collector, a first negative electrode film layer and a second negative electrode film layer. The second film layer is disposed at the inclined edge of the first film layer. The second film layer is flush with the middle of the first film layer or inclined towards the current collector. Carbon-based and silicon-based active materials are used, and the material content is limited to alleviate the formation of wavy edges and enhance the adhesion between the electrode and the separator.

Benefits of technology

It reduces the degree of lithium plating at the edge of the negative electrode, extends the cycle life of the secondary battery, improves the safety of the secondary battery, and maintains high energy density.

✦ Generated by Eureka AI based on patent content.

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    Figure CN116979020B_ABST
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Abstract

The application provides a negative electrode sheet, a secondary battery, a battery module, a battery pack and a power utilization device. The negative electrode sheet comprises: a first negative electrode film layer arranged on the surface of a negative electrode current collector, the upper surface of the first negative electrode film layer being inclined to the negative electrode current collector by an angle of 10-60°; and a second negative electrode film layer arranged along the inclined edge of the first negative electrode film layer; the upper surface of the second negative electrode film layer is flush with the upper surface of the middle part of the first negative electrode film layer, or the upper surface of the second negative electrode film layer is inclined to the negative electrode current collector by an angle of 5-55° and the upper surface of the second negative electrode film layer is not higher than the upper surface of the middle part of the first negative electrode film layer; the first negative electrode film layer comprises a carbon-based negative electrode active material, the second negative electrode film layer comprises a silicon-based negative electrode active material, the mass content of carbon in the first negative electrode film layer is 90-99.5%, and the mass content of silicon in the second negative electrode film layer is 1-77%. The application alleviates the formation of wavy edges of the negative electrode sheet, reduces the degree of lithium precipitation at the edge of the negative electrode sheet, and improves the cycle performance and safety of the secondary battery.
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