Battery Cell Case Wall Thickness for End-Expansion Control
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Solution Overview
Problem
Existing energy storage apparatuses face reliability issues due to uneven expansion and deformation of energy storage devices during charging and discharging, particularly at end portions where there is no reaction force to counteract expansion, leading to potential case breakage.
Innovation Solution
The energy storage apparatus is designed with a configuration where energy storage devices at end portions have a case with one side wall portion thicker than the other, adjacent to the opposing member, enhancing rigidity and controlling expansion without reducing capacity, and all devices have the same width for easier handling and manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wall thickness of the case is increased to suppress expansion and deformation of energy storage devices at end portions, then reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The case is designed with different wall thicknesses at different locations: the first side wall portion (at end portions adjacent to opposing members) has a greater wall thickness to suppress expansion, while the second side wall portion has a smaller wall thickness. This local differentiation provides enhanced reliability where needed without unnecessarily increasing complexity throughout the entire structure.
Solution Approach 2:
The case is segmented into different wall thickness regions, with the first side wall portion having a greater thickness and the second side wall portion having a smaller thickness. This segmentation allows targeted reinforcement at critical end portions while maintaining simpler construction in other areas, balancing reliability improvement with manufacturing feasibility.
2Ease of manufacture
If all energy storage devices have the same width for easier handling and manufacturing, then ease of manufacture is improved, but the ability to accommodate expansion at end portions worsens
Solution Approach 1:
While all energy storage devices maintain the same overall width for ease of manufacturing and handling, the case structure incorporates local quality variations through different wall thicknesses at the first and second side wall portions. This allows uniform device dimensions for simplified production while providing localized structural reinforcement to accommodate expansion at end portions.
Data Source
AI summary
An energy storage apparatus includes a pair of end members positioned in first direction and opposed to each other, and energy storage devices arrayed in the first direction between the pair of end members. Each of the energy storage devices includes an electrode assembly and a case accommodating the electrode assembly. The case has a pair of side wall portions opposed to each other. The energy storage devices include an energy storage device positioned adjacent to one of the end members such that a wall thickness of one side wall portion adjacent to the one of the end members is larger than a wall thickness of the other side wall portion in the energy storage device.