Battery Pack with Connecting Members for Low-Rigidity End Plate Restraint
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Solution Overview
Problem
Conventional battery packs with high-rigidity end plates are heavy and costly due to the need for robust materials to withstand internal pressure, leading to increased weight and expense.
Innovation Solution
A battery pack design featuring parallel arranged battery modules with connecting members extending through gaps between cells, using end plates with lower rigidity and insulating spacer portions for cooling medium passages, which reduces weight and cost while maintaining effective restraint and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-rigidity end plates are used to withstand internal pressure, then the restraining function is improved, but the weight and cost of the battery pack increase
Solution Approach 1:
The restraining function is divided between the end plates and the connecting members. The connecting members (restraining bands) are segmented elements that wrap around individual cells or groups of cells, distributing the restraining function across multiple discrete components rather than relying solely on rigid end plates. This segmentation allows the end plates to be lighter while the connecting members provide the necessary restraint force.
Solution Approach 2:
The connecting members are implemented as flexible bands or strips that can conform to the cell surfaces and provide restraining force through tension. These flexible elements replace the need for heavy rigid structures, as they can effectively restrain cell expansion through their elastic properties and wrapping configuration around the cells.
2Reliability
If high-rigidity end plates are used to prevent cell expansion, then the safety is improved, but the cost of the battery pack increases
Solution Approach 1:
The restraining system is segmented into multiple connecting members that can be independently applied to cells or cell groups. This segmentation allows for simpler manufacturing processes compared to fabricating and installing large rigid end plates, as the connecting members can be individually wrapped and secured around cells using standard assembly techniques.
Solution Approach 2:
The flexible connecting members are typically made from cost-effective materials such as fabric strips, rubber bands, or polymer films that can be easily manufactured and applied. These flexible elements provide adequate safety restraint at lower material and manufacturing costs compared to the metal or composite materials required for high-rigidity end plates.
3Strength
If connecting members extend through gaps between cells, then the restraint effectiveness is improved, but the device complexity increases
Solution Approach 1:
The connecting members serve multiple functions: they restrain cell expansion, provide structural connection between cells, and allow for tension adjustment. This multi-functionality reduces the need for separate components for each function, thereby reducing overall device complexity despite the extended configuration through cell gaps.
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
The design achieves weight and cost reductions by using lightweight, low-rigidity end plates and insulating spacer portions for cooling, enhancing assembly productivity and safety under severe conditions.
Implementation Method 1
expansion of the cases due to internal pressure of the cells or expansion of the elements for electromotive force is restrained by tension of the connecting members extending through the gaps at both ends of the battery modules and between two given cells in the middle of the battery module
Implementation Method 2
The cells of the battery modules are then cooled effectively from their side faces by the cooling medium flowing through the cooling medium passages
Data Source
AI summary
The battery pack uses a restraining tool capable of secure restraint despite relatively low rigidity to achieve weight and cost reductions. The battery pack is formed of a plurality of parallel arranged battery modules (2), each consisting of a plurality of cells (5) electrically connected in series and coupled together in one piece with gaps (8) formed therebetween (5, 5), each cell being formed of elements for electromotive force encased in a prismatic case. The restraining tool includes connecting members (4) extending through the gaps (8) at both ends of the parallel arranged battery modules (2) and between two given cells (5, 5).