Battery Lead Weld Bump for Stress Relief
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Solution Overview
Problem
The existing battery designs face issues with stress concentration and crack formation at the boundary between the weld and non-weld regions of the lead, leading to potential breakage and increased electric resistance due to deformation of the weld region during the welding process.
Innovation Solution
Incorporating a first bump along the longitudinal direction of the lead, which has a projecting shape corresponding to the cross-section boundary between the weld and non-weld regions, to enhance tensile strength and reduce stress concentration, thereby preventing crack formation and maintaining low electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead is welded to the sealing member, then electrical connection is established, but stress concentration occurs at the boundary between weld region and non-weld region causing cracks
Solution Approach 1:
The weld region is designed with non-uniform thickness distribution, creating a local thick portion that provides enhanced mechanical strength at the boundary between weld and non-weld regions. This local quality enhancement specifically addresses the stress concentration issue without affecting the overall electrical connection function.
Solution Approach 2:
The lead structure is pre-designed with a thick portion located at the boundary region before welding occurs. This preliminary structural preparation ensures that when stress occurs during or after welding, the thick portion is already in position to absorb and distribute the stress, preventing crack formation.
2Strength
If the weld region is deformed during welding, then the lead is securely attached to the sealing member, but the weld region thins and becomes prone to cracking
Solution Approach 1:
Instead of maintaining uniform thickness throughout the weld region, the invention introduces a local thick portion specifically at the boundary area. This local quality differentiation ensures that the region most susceptible to cracking (the boundary) has enhanced thickness and strength, while other areas can be deformed during welding to achieve secure attachment.
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 first bump effectively suppresses crack occurrence and enhances the reliability of the battery by maintaining the strength of the weld region and reducing electric resistance, even under deformation, thus improving the overall performance and durability of the battery.
Implementation Method 1
one end of a lead is welded to the sealing member inside the battery case
Data Source
AI summary
A battery includes: an electrode group including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; an electrolyte; a container for accommodating the electrode group and the electrolyte; a sealing member for blocking an opening in the container; and a first lead for electrically connecting the first electrode to the sealing member. The first lead has a weld region welded to the sealing member, and the weld region has at least one first bump along the longitudinal direction of the first lead. The cross section of the boundary between the weld region and a non-weld region on the first electrode side has a projecting shape corresponding to the bump.