Battery Stack Fastening Member for Strength and Stretchability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply devices face a challenge in balancing the need for increased strength and stretchability in fastening secondary battery cells due to their expansion and contraction during charging and discharging, particularly with high-capacity batteries, leading to potential breakage at joint portions.
Innovation Solution
A power supply device design featuring fastening members with distinct fastening parts and intermediate parts, where the fastening parts are stronger and the intermediate parts are more stretchable, made from differential thickness materials and welded for enhanced joint reliability, allowing both strength and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the strength of the binding bar is increased to prevent breakage at joint portions, then the resistance to expansion is improved, but the stretchability deteriorates
Solution Approach 1:
The binding bar is divided into two distinct parts: a fastening part with higher strength and an intermediate part with higher stretchability. This segmentation allows each part to perform its specific function optimally - the fastening part provides strong anchoring at the end plates while the intermediate part accommodates expansion through elastic deformation.
Solution Approach 2:
Different parts of the binding bar are given different material properties - the fastening part is made with higher strength characteristics for secure attachment, while the intermediate part is made with higher stretchability characteristics for accommodating battery expansion. This local differentiation of properties resolves the contradiction between overall strength and local flexibility.
2Power
If high-capacity secondary battery cells are used to increase power supply, then the expansion amount increases, but the load on joint portions increases causing potential breakage
Solution Approach 1:
The intermediate part of the binding bar is designed with higher stretchability to act as a cushioning element that absorbs expansion forces before they reach the joint portions. This pre-designed flexibility protects the welded joints from excessive stress that would otherwise cause breakage in high-capacity battery applications.
Data Source
AI summary
The power supply device includes: a plurality of secondary battery cells each including a prismatic exterior can; a pair of end plates covering both end surfaces of a battery stack body in which the plurality of secondary battery cells are stacked; and a plurality of fastening members made of metal each having a plate shape extending in a stack direction of the plurality of secondary battery cells and disposed on an opposing side surface of the battery stack body to fasten the end plates to each other, in which each of the plurality of fastening members includes fastening part fixed to the end plate at each of both ends in a longer direction, and intermediate part coupling fastening parts with each other, and fastening parts is higher in strength than intermediate part, and intermediate part is higher in stretchability than fastening parts.