Stacked Battery Tab Resistance for Sneak Current Suppression
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Solution Overview
Problem
Stacked batteries with varying short circuit resistances among cells experience sneak current issues, leading to uneven temperature distribution and material deterioration during nail penetration tests, as cells with low resistance heat up due to current flow from high to low resistance cells.
Innovation Solution
The battery design includes surface-side and center-side cells with cathode and anode current collecting tabs having specific resistance, thickness, and area differences to manage short circuit resistance unevenness, with surface-side cells having higher resistance and smaller dimensions to mitigate sneak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cells are electrically connected in parallel to increase battery capacity, then battery energy storage is improved, but sneak current occurs due to resistance differences causing temperature increase and material deterioration
Solution Approach 1:
The patent applies local quality by making the current collecting tabs of surface-side cells different from those of center-side cells. Specifically, surface-side cells have tabs with larger resistance (achieved through smaller area, thinner thickness, or different material) to compensate for their lower short circuit resistance. This local differentiation ensures uniform current distribution across all parallel-connected cells, preventing sneak current while maintaining high battery capacity.
2Loss of energy
If current collecting tabs are made with larger area and thinner thickness to reduce resistance, then electrical conductivity is improved, but manufacturing complexity increases due to precise resistance control requirements
Solution Approach 1:
Instead of uniformly minimizing resistance across all cells, the patent applies local quality by differentiating tab specifications between surface-side and center-side cells. This approach balances the resistance differences caused by cell location, achieving uniform current distribution without requiring extremely precise resistance control for every individual cell.
Solution Approach 2:
The patent changes the resistance parameter of current collecting tabs based on cell location. Surface-side cells use tabs with higher resistance (smaller area, thinner thickness) while center-side cells use tabs with lower resistance (larger area, greater thickness). This parameter differentiation compensates for the inherent resistance differences in parallel-connected cells and prevents sneak current.
3Ease of manufacture
If uniform current collecting tabs are used across all cells, then manufacturing ease is improved, but uneven current distribution occurs leading to temperature increase and material deterioration
Solution Approach 1:
The patent applies local quality by differentiating current collecting tab specifications between surface-side cells and center-side cells. Surface-side cells have tabs with larger resistance to compensate for their lower short circuit resistance, while center-side cells have tabs with smaller resistance. This local differentiation ensures uniform current distribution and temperature across all cells, preventing material deterioration while maintaining manufacturing feasibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses sneak current and reduces material deterioration by controlling current flow and temperature distribution within the battery, enhancing safety and longevity.
Implementation Method 1
When the sneak current occurs, the temperature of the cell with low short circuit resistance (the cell to which the current flowed into) increases
Data Source
AI summary
An objective of the present disclosure is to provide a stacked battery that suppresses sneak current caused by an unevenness of a short circuit resistance among a plurality of cells. The present disclosure provides a stacked battery comprising: a plurality of cells in a thickness direction, wherein the plurality of cells are electrically connected in parallel; the stacked battery includes a surface-side cell that is located on a surface side of the stacked battery, and a center-side cell that is located on a center side rather than the surface-side cell; wherein a resistance of the cathode current collecting tab in the surface-side cell is more than a resistance of the cathode current collecting tab in the center-side cell; or a resistance of the anode current collecting tab in the surface-side cell is more than a resistance of the anode current collecting tab in the center-side cell.