Battery Assembly Tab Design for Uniform Current Distribution
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Solution Overview
Problem
Rechargeable battery assemblies and packs face challenges in managing welding quality, achieving uniform current distribution, and ensuring safety due to non-uniform insulation between cells, leading to reduced output and potential explosion risks during high-current discharge.
Innovation Solution
The design involves setting equivalent distances from electrode terminals to connection holes on tabs connecting cells in parallel, with holders providing insulation and symmetric structures to maintain uniform current distribution and prevent cell separation, allowing for high-current discharging and improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cells are connected in parallel or series with tabs, then large capacity and high voltage are realized, but non-uniform current distribution occurs due to difference in discharging path lengths
Solution Approach 1:
The patent applies asymmetry by intentionally designing different tab configurations for different cell types. Specifically, cylindrical cells use tabs with connection holes positioned at one end, while prismatic cells use tabs with connection holes positioned at the center. This asymmetric design compensates for the inherent geometric differences between cell types, ensuring that the current path lengths become equivalent despite the cells having different shapes and internal structures.
2Quantity of substance
If multiple cells are connected in a pack, then large capacity is achieved, but welding quality management becomes difficult and productivity deteriorates
Solution Approach 1:
The patent applies local quality by optimizing the tab design specifically at the connection points where cells are joined. The tabs are designed with connection holes positioned at specific locations (end for cylindrical cells, center for prismatic cells) to ensure uniform current distribution. This localized optimization at the critical connection interface eliminates the need for complex welding quality management across the entire pack assembly process.
3Quantity of substance
If cells are connected in parallel, then capacity is increased, but non-uniform current distribution causes lower output and accelerated deterioration
Solution Approach 1:
The patent applies equipotentiality by designing the tab connection structure to ensure that all cells in parallel connection have equivalent electrical potential and current path lengths. By positioning the connection holes at appropriate locations on each cell type's tab, the patent creates equal resistance paths for current flow, ensuring uniform current distribution across all parallel-connected cells. This maintains high discharge output while scaling capacity.
4Device complexity
If insulation between cells is not properly realized, then assembly complexity is reduced, but consecutive explosion may occur from firing of a single cell
Solution Approach 1:
The patent applies the intermediary principle by introducing holder cases as mediating structures between adjacent cells. These holder cases serve as insulating barriers that physically separate and electrically insulate the cells from each other. The holder cases are designed with simple geometries that fit around the cells, providing effective insulation without adding significant structural complexity to the overall battery assembly.
Data Source
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AI summary
One aspect of the present invention is to provide a rechargeable battery assembly (100) that can assure high-current discharging characteristic by applying a plurality of cells and realize uniform current distribution to each cell. A rechargeable battery assembly (100) according to an embodiment of the present invention includes a plurality of cells (10), each formed of a rechargeable battery, first and second holders (21, 22) receiving the cells (10) and coupled to each other, a first tab connecting first terminals (11) of the cells (10) in parallel in the first holder side, and a second tab (32) connecting second terminals (12) of the cells (10) in parallel in the opposite side of the first tab (31), and first distances L1 from respective centers of the first terminals to a connection hole formed in a first center (C1) of the first tab (31) are set to be equivalent to each other.