Battery Pack With Equalized Electrode Tab Lengths
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Solution Overview
Problem
Existing battery packs for devices like electric bicycles and motorcycles face issues with uneven current flow due to differing lengths of positive and negative electrode wires, and require a lightweight, high-strength design to withstand vibration and shock.
Innovation Solution
A battery pack design where positive and negative electrode pull-out tabs are aligned on the same side, with extension tabs connected perpendicularly and bent along the battery stacking surface for equal wire lengths, and reinforced with a common insulation member to prevent short circuits, allowing for flexible mounting directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If positive- and negative-electrode pull-out tabs are taken out from different sides of each unit battery, then the battery structure is simplified, but the wire lengths become unequal causing uneven current flow
Solution Approach 1:
The patent applies asymmetry by configuring the battery holding body with asymmetric tab holding portions that guide both positive and negative electrode tabs to emerge from the same side of the battery module, despite the symmetric stacking arrangement. This asymmetric configuration of tab emergence points ensures equal wire lengths from positive and negative electrodes to the external terminals, resolving the current flow uniformity issue while maintaining structural simplicity
Solution Approach 2:
The patent achieves equipotentiality in terms of electrical path length by designing the tab holding portions and extension tabs such that the total wire length from positive electrode to external terminal equals the total wire length from negative electrode to external terminal. This equalizes the electrical resistance paths, ensuring uniform current distribution across all battery modules in the stack
2Weight of moving object
If a lightweight battery pack is designed, then the weight is reduced, but the strength and vibration resistance may be compromised
Solution Approach 1:
The patent employs thin film exterior materials that tightly wrap and conform to the battery elements, providing lightweight yet effective mechanical support and vibration damping. The film structure distributes mechanical stresses across the battery surface, maintaining strength while minimizing added weight
Solution Approach 2:
The patent merges multiple functions into the battery holding body structure: it provides mechanical support for stacking, guides tab alignment, holds extension tabs, and provides insulation. This integration eliminates the need for separate components, reducing overall weight while maintaining structural integrity and vibration resistance
3Manufacturing precision
If extension tabs are bent along the side surface and stacked up, then equal wire lengths are achieved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the extension tabs with the required bends and shapes during the battery module assembly process. The tabs are configured in advance to extend perpendicularly from the pull-out tabs and bend along the side surfaces, so that when modules are stacked, the wire length equality is automatically achieved without requiring additional post-assembly adjustments
Solution Approach 2:
The tab holding portions of the battery holding body are designed to automatically guide and position the extension tabs during stacking. The structural features of the holding body itself perform the alignment and positioning functions, eliminating the need for external fixtures or complex alignment procedures, thereby reducing manufacturing complexity
Data Source
AI summary
Provided is a battery pack that is unlikely to be affected by vibration, shock, or the like, and has stable characteristics.A battery pack includes a battery module 300 that is made by stacking battery holding bodies 200 on which film-covered batteries are placed with positive- and negative-electrode pull-out tabs being taken out from the same side in such a way that sides from which the positive- and negative-electrode pull-out tabs are pulled out are aligned with each other, wherein: an extension tab connected each of the tabs is pulled out from a battery holding body in such a way as to extend in a direction perpendicular to a direction of the pull-out tab and in a direction opposite to the other pull-out tab; and the extension tabs are each bent along a side surface in a direction perpendicular to a battery stacking surface, and are stacked up and electrically connected.