Secondary Battery Welding Assembly Stress Release Structure
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Solution Overview
Problem
The existing welding processes for secondary batteries, particularly lithium-ion batteries, suffer from stress concentration and cracking issues due to thermal expansion and contraction, leading to potential safety risks from electrolyte leakage, as the full-length welding seams retain stress and are difficult to detect.
Innovation Solution
A welding assembly for the liquid-injection hole of a secondary battery that includes a stress release structure, such as annular slots or an annular boss, on the sealing cover-plate and top cover, designed to release stress from the welding seam, preventing crack formation by distributing stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full-length welding is performed on the welding portion, then sealing reliability is improved, but welding stress concentration increases causing cracks
Solution Approach 1:
The patent divides the continuous welding seam into multiple segments by introducing stress release slots that break the continuity of the welding portion. This segmentation allows stress to be released at designated locations while maintaining sealing integrity at the battery case, resolving the contradiction between sealing reliability and welding seam strength.
Solution Approach 2:
The stress release slots act as intermediary structures that provide a controlled path for stress release. These slots are strategically positioned to allow the welding seam to maintain its sealing function while providing designated areas where stress can be relieved without compromising the overall structural integrity.
2Reliability
If stress release structure is added to the welding assembly, then welding crack prevention is improved, but device complexity increases
Solution Approach 1:
The stress release slots are introduced only at specific critical locations within the welding portion where stress concentration is most likely to occur. This localized approach provides crack prevention functionality without adding complexity to the entire welding assembly, maintaining simplicity while addressing the specific problem of stress-induced cracking.
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 stress release structure effectively prevents welding cracks by releasing stress during the welding process, enhancing the reliability and safety of the battery by reducing the likelihood of electrolyte leakage.
Implementation Method 1
the stress release structure is provided at one side or both sides of the welding portion, and is configured to release stress from the welding portion
Implementation Method 2
Stress will be formed in the welding process due to thermal expansion and contraction
Implementation Method 3
the welding portion 400 between the sealing cover-plate 40 and the liquid-injection hole 20 in a manner of laser full-length welding
Data Source
AI summary
A welding assembly for a liquid-injection hole of a secondary battery, including a top cover of a case, a liquid-injection hole, a sealing cover-plate and a stress release structure, wherein the liquid-injection hole is disposed in the top cover and includes a assembling recess and a through-hole arranged sequentially from top to bottom of the top cover, the assembling recess and the through-hole present a stepped transition and the radial dimension of the assembling recess is larger than that of the through-hole. The sealing cover-plate is accommodated in the assembling recess and the stress release structure is provided at one or both sides of the welding portion and capable of releasing stress from the welding portion. The welding assembly provides a stress release structure nearby the welding portion, and when the welding portion is full-strength welded, the stress-release structure can effectively release stress nearby the welding seam.