Battery Stack Buffer Assembly for Cell Height Variation
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Solution Overview
Problem
Existing power supply devices for vehicles face issues with uneven stress distribution on secondary battery cells due to variations in height caused by charging and discharging, leading to potential deterioration and instability during vibration or impact.
Innovation Solution
A power supply device configuration that includes a buffer system with flexible resin covers and metal plates to absorb height differences and distribute stress evenly across secondary battery cells, ensuring uniform pressure and enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the upper surface of the battery stack is uniformly pressed to make heights uniform, then the stability of the battery stack is improved, but the stress applied to individual secondary battery cells becomes uneven leading to deterioration
Solution Approach 1:
The buffer is divided into multiple independent buffer portions, each corresponding to individual secondary battery cells. This segmentation allows each buffer portion to independently absorb height variations of individual cells while distributing stress uniformly, preventing concentration of stress on specific cells and thereby maintaining both stack stability and cell reliability.
Solution Approach 2:
The buffer acts as an intermediary component between the pressing mechanism and the secondary battery cells. It mediates the force transmission by absorbing height differences through elastic deformation, ensuring that pressing forces are distributed evenly across all cells without causing localized stress concentration that would lead to deterioration.
2Quantity of substance
If secondary battery cells are stacked to increase capacity, then the energy storage capability is improved, but the risk of displacement due to vibration or impact increases
Solution Approach 1:
The buffer provides beforehand cushioning by being pre-installed between the end plate and secondary battery cells. This cushioning effect is activated in advance to absorb impact forces from vibrations or drops, preventing displacement of stacked cells and maintaining stack stability while allowing the battery capacity to be increased through additional cell stacking.
3Strength
If the bind bar is bent and pressed against the corner to prevent displacement, then the mechanical constraint is improved, but the stress distribution on battery cells becomes uneven
Solution Approach 1:
Instead of applying constraint force at a single corner location, the buffer provides distributed local quality by placing multiple buffer portions at different locations corresponding to individual battery cells. This allows the mechanical constraint to be maintained while the stress is evenly distributed across all cells through the elastic properties of the buffer material.
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 buffer system effectively disperses stress uniformly across secondary battery cells, reducing the risk of deterioration and improving the reliability and longevity of the power supply device, even under varying conditions such as vibration or impact.
Implementation Method 1
a connecting part, having flexibility, for connecting two of the plurality of covers
Data Source
AI summary
Power supply device includes a plurality of secondary battery cells, a pair of end plates that cover both end faces of battery stack in which the plurality of secondary battery cells are stacked, a plurality of fastening members that fasten end plates to each other, a plurality of pressing parts that press upper surfaces of the plurality of secondary battery cells respectively, and buffer interposed between pressing parts and the upper surfaces of secondary battery cells. Buffer includes a plurality of covers made of resin, and a connecting part, having flexibility, for connecting two of the plurality of covers. Buffer is configured such that each of the plurality of covers is disposed on the upper surface of corresponding one of secondary battery cells, and each of pressing part abuts on the upper surface of the corresponding cover.