Rechargeable Battery Tab Wrapping for Short-Circuit Prevention
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Solution Overview
Problem
Rechargeable batteries face issues with short-circuiting due to swelling during charging or discharging, particularly when the electrode tabs come into contact with the case, leading to potential electrical shorts.
Innovation Solution
The rechargeable battery design incorporates a unique winding structure with a non-tab part that wraps the tab part multiple times, creating a separation distance between the electrode tabs and the case, preventing short-circuits by forming a buffer space that maintains electrical isolation even if the electrode assembly swells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode assembly is wound with tabs protruding out, then the electrical connection is improved, but the risk of short-circuit due to swelling increases
Solution Approach 1:
The non-tab part of the first electrode acts as an intermediary buffer between the protruding tabs and the case. When the electrode assembly swells, this non-active-material region absorbs the expansion stress and maintains separation, preventing direct contact between tabs and case while preserving electrical connectivity through the coated regions.
Solution Approach 2:
The first electrode is segmented into distinct functional regions: a non-tab part (without active material) that wraps around the tab part (with active material). This segmentation allows the non-tab part to serve as a dedicated buffer zone that doesn't participate in electrochemical reactions but provides mechanical protection against short-circuiting.
2Reliability
If the tab part is made larger to improve electrical connection, then the electrical conductivity is improved, but the space for active material coating is reduced
Solution Approach 1:
The electrode is divided into functional segments: the tab part with active material coating for electrical connection, and the non-tab part without active material that wraps around it. This segmentation allows the tab part to be sufficiently large for good electrical contact while the non-tab part provides the necessary buffer space without consuming active material capacity.
Solution Approach 2:
Different regions of the electrode have different qualities: the tab part has active material coating for electrical conductivity, while the non-tab part deliberately lacks active material to serve as a buffer. This local differentiation optimizes both electrical connection and swelling accommodation without compromising overall battery capacity.
Data Source
AI summary
A rechargeable battery includes an electrode assembly including a first electrode, a second electrode, and a separator, the first electrode and the second electrode being wound with the separator therebetween, and a case to receive the electrode assembly, wherein the first electrode includes a first tab part having a first coating region and a plurality of first uncoated tabs protruding out of the first coating region, the first coating region being coated with a first active material, and the plurality of first uncoated tabs not being coated with the first active material, and a first non-tab part connected to the first tab part, the first non-tab part wrapping the first tab part at an outermost portion thereof at least one time.