Battery Module Tab Lead Structure for Cell Expansion Stress
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Solution Overview
Problem
Conventional battery modules face stress and potential deterioration or breakage of tab leads due to variations in battery cell expansion and contraction, particularly in solid-state batteries, where existing configurations do not adequately account for the expansion and contraction of battery cells.
Innovation Solution
The battery module design features tab leads with orthogonal extensions and cushioning materials between battery cells and end plates, allowing for reduced stress application during expansion and contraction, with cooling members positioned between cells for improved heat transfer and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tab leads are disposed along the stacking direction for battery cells, then electrical connection between adjacent battery cells is achieved, but stress is applied to tab leads during battery cell expansion and contraction, causing deterioration or breakage
Solution Approach 1:
The tab lead is configured to extend in directions orthogonal to the stacking direction of battery cells, changing the spatial orientation from longitudinal (along stacking direction) to transverse (perpendicular to stacking direction). This dimensional reorientation allows the tab lead to connect adjacent battery cells electrically while avoiding alignment with the expansion/contraction axis, thereby reducing stress application during charge-discharge cycles.
2Strength
If battery cells are retained by end plates in stacking direction, then structural support is provided, but variation in expansion amount by each battery cell causes stress concentration on tab leads
Solution Approach 1:
The tab lead is designed with different extension characteristics in different spatial directions, creating local quality variations in stress distribution. By extending primarily in directions orthogonal to the stacking direction rather than uniformly in all directions, the tab lead concentrates its structural strength where needed for electrical connection while minimizing stress exposure in the expansion direction.
3Device complexity
If conventional tab lead configuration is used, then simple electrical connection is achieved, but tab leads are susceptible to deterioration and breakage from expansion-induced stress
Solution Approach 1:
The tab lead configuration transitions from a simple linear arrangement along the stacking direction to a multi-directional extension pattern with orthogonal components. This spatial reconfiguration, while maintaining electrical connectivity function, strategically positions the tab lead extensions to traverse directions minimal in expansion displacement, thereby reducing cumulative stress and improving durability without significantly increasing device complexity.
Data Source
AI summary
The battery module includes a plurality of battery cells, each battery cell being provided with an electrode stack accommodated in an exterior body and a tab lead that is connected to the electrode stack and extends from the exterior body, the battery module having a pair of end plates that retain the battery cells, the end plates being disposed at both ends of the electrode stacks in an electrode stacking direction, the tab lead being electrically connected to the tab lead of another of the battery cells that is adjacent, and the tab lead having a first extension that extends in a direction orthogonal to the electrode stacking direction and a second extension that extends in a direction in which the another of the battery cells is adjacent.