A secondary battery and an electronic device

By using a separator structure combining a nonwoven membrane with high mechanical strength and a microporous membrane in lithium-ion batteries, the problems of decreased adhesion and energy density loss of the separator at high temperatures are solved, thereby improving the cycle performance and high-temperature thermal performance of the battery.

CN117977015BActive Publication Date: 2026-07-24NINGDE AMPEREX TECHNOLOGY LTD
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Patent Information

Application Number
CN202410276081.1
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-03-11
Publication Date
2026-07-24
Estimated Expiration
2044-03-11

AI Technical Summary

Technical Problem

Existing lithium-ion battery separators have low melting points at high temperatures, which leads to reduced adhesion and affects the battery's cycle performance and safety performance. At the same time, the thickness of non-woven membranes reduces energy density.

Method used

A first diaphragm is formed by combining a nonwoven membrane with high mechanical strength and high glass transition temperature with a first adhesive layer with high ionic conductivity. A second diaphragm is formed by combining a microporous membrane with lower glass transition temperature and thinner thickness with a second adhesive layer with higher melting point, thereby improving adhesion and thermal stability.

Benefits of technology

It improves the cycle performance and high-temperature thermal performance of lithium-ion batteries while maintaining high energy density and reducing the risk of short circuits caused by separator shrinkage at high temperatures.

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Abstract

The application provides a secondary battery and an electronic device. The secondary battery comprises an electrode assembly, the electrode assembly is in a winding structure, the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, a first separator and a second separator, the negative electrode sheet is located between the first separator and the second separator, the first separator comprises a first base film and a first adhesive layer, the second separator comprises a second base film and a second adhesive layer, the first adhesive layer comprises a first adhesive, and the second adhesive layer comprises a second adhesive. The first base film is a non-woven fabric film, the first adhesive comprises at least one of polyvinylidene fluoride or polyvinylidene fluoride-hexafluoropropylene copolymer. The second base film is a microporous film, and the second adhesive comprises at least one of polyimide, polyvinyl alcohol or sodium carboxymethyl cellulose. Through the above arrangement, the adhesion between the separator and the positive electrode sheet and the adhesion between the separator and the negative electrode sheet can be improved, the cycle performance and high-temperature hot box performance of the secondary battery are improved, and the secondary battery also has a high energy density.
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