Battery Tab Fixing Structure for Electrode Stack Expansion
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Solution Overview
Problem
Existing nonaqueous electrolyte batteries face tab breakage due to uneven tension distribution during electrode stack expansion and contraction, particularly at the uppermost and lowermost surfaces, leading to potential short circuits and performance degradation.
Innovation Solution
The battery design incorporates a tab fixing member between adjacent electrode tabs to equalize tension by dividing the tabs into parts subjected to expansion and convergence, using insulating or conductive members to stabilize the connection points, thereby suppressing tab breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode stack expands during charge, then the battery capacity increases, but the tabs experience uneven tension causing breakage
Solution Approach 1:
The patent applies different structural treatments to different regions of the tabs. Specifically, the upper and lower surfaces of the tabs (which experience higher tension during expansion) are given different properties from the central region. This is achieved by forming protrusions on one surface and grooves on the other surface of the tabs, creating local quality differences that distribute stress more evenly and prevent breakage while maintaining overall tab strength during battery capacity expansion.
2Adaptability or versatility
If the tabs are made longer to accommodate expansion, then the battery can handle larger expansion amounts, but the tension on the tabs increases leading to breakage
Solution Approach 1:
The patent segments the tab structure by forming protrusions and grooves that divide the tab into multiple regions. This segmentation allows each region to handle stress independently, with the protrusions and grooves acting as stress distribution features. The segmented structure enables the tab to accommodate larger expansion amounts without concentrating tension in a single location, thereby preventing breakage while maintaining adaptability to expansion.
3Strength
If the tabs are constrained to prevent breakage, then tab strength is maintained, but the natural expansion and contraction of the electrode stack is restricted
Solution Approach 1:
The patent creates a dynamic tab structure where the protrusions and grooves can deform and flex during battery operation. This dynamic structure allows the tabs to naturally expand and contract with the electrode stack while the geometric features of the protrusions and grooves distribute the resulting tensions. The dynamic design maintains tab strength through stress distribution rather than rigid constraint, preserving both tab integrity and electrode stack stability.
Data Source
AI summary
To provide a nonaqueous electrolyte battery capable of suppressing breakage of tabs even when an electrode stack constituting the nonaqueous electrolyte battery expands due to charge and discharge. Each tab is divided into a part to which tension is applied at the time of volume expansion of an electrode stack and a part where tabs converge (electrical connection part with the outside), and the tension applied to the part of each tab where the tabs converge is made equal. Specifically, a tab fixing member is disposed between negative electrode tabs and/or between positive electrode tabs, thereby suppressing an increase in tension between the tab fixing member and a negative electrode tab convergence part and/or a positive electrode tab convergence part.