Battery Stack Binding Bar Rigidity via Engaging Steps
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Solution Overview
Problem
Conventional power supply devices for vehicles face challenges in maintaining sufficient rigidity to bind secondary battery cells together, especially with increased expansion due to high output demands, leading to potential binding bar failure and increased weight or cost when attempting to enhance rigidity.
Innovation Solution
The power supply device incorporates binding bars with engaging steps and protrusions that intersect with the stack direction, along with reinforcing members and bolt fixation, to increase rigidity without altering the thickness or material of the binding bars, thereby distributing stress evenly and preventing concentration on bent edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of binding bars is increased to enhance rigidity, then the binding strength increases, but the weight of the binding bars increases
Solution Approach 1:
The binding bar features local thickening at the bent edges where it contacts the end plates, while the central portion maintains original thickness. This localized reinforcement increases binding strength at critical stress points without proportionally increasing overall weight, resolving the contradiction between binding strength and weight.
Solution Approach 2:
The binding bar is constructed as a composite structure combining a base bar with additional reinforcing plates or ribs at strategic locations. This composite design provides enhanced rigidity and binding strength at the bent edges while minimizing additional weight compared to a uniformly thick binding bar.
2Reliability
If the binding bars are made of more rigid material to prevent opening or breaking, then the reliability increases, but the manufacturing cost increases
Solution Approach 1:
Instead of using expensive rigid material throughout the entire binding bar, the invention applies local reinforcement only at the bent edges through thickening or adding reinforcing plates. This allows the use of standard materials for the majority of the bar while providing enhanced reliability at critical stress points, reducing overall manufacturing cost.
Solution Approach 2:
The binding bar is segmented into different structural zones: a standard thickness central portion and reinforced bent edge portions. This segmentation allows differential material selection or processing, using cost-effective materials for the non-critical central portion while providing enhanced reliability at the critical bent edges through localized reinforcement.
3Stress or pressure
If the thickness of binding bars is increased to distribute stress evenly, then the stress distribution improves, but the weight increases
Solution Approach 1:
The binding bar features localized thickening at the bent edges where stress concentration occurs during battery expansion. This local reinforcement improves stress distribution at critical points without requiring uniform thickness throughout, thereby minimizing weight increase while achieving better stress distribution where it is most needed.
Data Source
AI summary
A power supply device includes: a battery stack body that includes a plurality of secondary battery cells that are stacked; a pair of end plates disposed on both end surfaces of the battery stack body, respectively; and binding bars that are disposed on both the end surfaces of the battery stack body, respectively, and bind the pair of end plates. Each of the binding bars includes engaging steps that are opposite the pair of end plates, respectively. Each of the engaging steps extends in a direction intersecting with a stack direction of the battery stack body. Each of the pair of end plates includes engaging protrusions that are opposite the binding bars, respectively. The engaging protrusions engage with engaging steps. Consequently, rigidity that binds the battery stack body together is increased without changing a material and a thickness of the binding bars.