Secondary battery, electronic device, and power tool

By employing an electrode winding structure in lithium-ion batteries, the non-covered portions of the active materials of the positive and negative electrodes are overlapped and wound in opposite directions and laser-welded, solving the internal short-circuit problem during high-rate discharge and achieving safety and reliability of high-output discharge.

CN115066776BActive Publication Date: 2026-07-10MURATA MFG CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
MURATA MFG CO LTD
Filing Date
2021-01-29
Publication Date
2026-07-10

AI Technical Summary

Technical Problem

When existing lithium-ion batteries discharge at high rates, deformation of the inner periphery of the electrode winding can cause the active material to peel off, potentially leading to an internal short circuit.

Method used

The electrode winding structure is adopted, in which the non-covered active materials of the positive and negative electrodes are overlapped and wound in opposite directions, and joined to the current collector by laser welding to form a flat surface. The groove is pre-formed to prevent wrinkles, and the current collector is welded to the non-covered active material at multiple points to reduce internal resistance.

Benefits of technology

This technology prevents internal short circuits during high-output discharge, improving battery safety and reliability.

✦ Generated by Eureka AI based on patent content.

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    Figure CN115066776B_ABST
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Abstract

A secondary battery in which a positive active material non-covered portion is joined to a positive current collector plate at one end of an electrode roll body, a negative active material non-covered portion is joined to a negative current collector plate at the other end of the electrode roll body, the electrode roll body has a flat surface formed by bending and overlapping the center axis of the structure wound in either one or both of the positive active material non-covered portion and the negative active material non-covered portion, and a groove formed in the flat surface, the positive electrode has a positive electrode cutout portion at one end in the short side direction of the positive electrode on the winding start side of the electrode roll body, the negative electrode has a negative electrode cutout portion at one end in the short side direction of the negative electrode on the winding start side of the electrode roll body, the end of the positive electrode cutout portion is present in the positive active material non-covered portion, and the end of the negative electrode cutout portion is present in the negative active material non-covered portion.
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