Sealed Battery Welding Uniformity via Annular Ridge
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Solution Overview
Problem
Conventional sealed batteries face challenges in achieving uniform thermal capacity during welding due to varying distances from the opening circumference to the lid member periphery, leading to inconsistent weld quality and strength issues across different directions.
Innovation Solution
The implementation of an annular ridge with an annular recess and groove around the opening circumference, where the sealing member is welded along the entire circumference, helps to distribute heat uniformly, reducing the impact of external structures and allowing for consistent welding conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed around the entire circumference of the opening in a flat-shaped sealed battery, then hermetic sealing is achieved, but weld quality varies depending on direction due to non-uniform thermal capacity
Solution Approach 1:
The patent applies local quality by creating a recessed portion in the lid member at the opening location. This localized structural modification increases the thermal capacity specifically at the welding location, allowing uniform welding conditions around the entire circumference. The recessed portion acts as a heat reservoir that compensates for the otherwise non-uniform thermal distribution caused by the flat lid geometry and varying distances to peripheral structures.
2Strength
If welding conditions are set for slow temperature rise areas, then adequate penetration is achieved in those areas, but spatter occurs in fast temperature rise areas due to overheating
Solution Approach 1:
The patent changes the thermal parameter (thermal capacity) locally by introducing a recessed portion in the lid member. This structural change increases the effective thermal capacity at the opening location, which slows down the temperature rise rate during welding in previously fast-heating areas. This allows uniform welding parameters to be applied around the entire circumference without causing spatter from overheating in any direction.
3Weight of moving object
If the lid member is made thin to reduce weight, then battery weight decreases, but thermal capacity during welding becomes insufficient leading to non-uniform weld quality
Solution Approach 1:
The patent segments the lid member structure by creating a localized recessed portion at the opening area. This segmentation allows the lid member to maintain overall thinness for weight reduction while having a specific localized region with increased thermal capacity. The recessed portion serves as a heat reservoir without requiring the entire lid member to be thick, thus resolving the contradiction between weight reduction and welding thermal capacity.
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
This approach ensures uniform weld quality and strength around the entire circumference, addressing the issue of inconsistent thermal capacity and achieving optimal sealing under constant welding conditions.
Implementation Method 1
the sealing member is joined by welding along an entire circumference thereof to the inner wall surface of the annular ridge
Data Source
AI summary
The sealed battery has a battery container (4, 5) and a power generating element sealed inside the battery container. The battery container is provided with a fill opening (12), an annular ridge (16), which extends around the entire circumference of the outer face surrounding the fill opening, and an annular indentation (15) on the inside of the inner wall surface of the annular ridge, and has a sealing cap (8), which fits into the annular indentation and covers the fill opening. The sealing cap is joined by being welded to the inner wall surface of the annular ridge around the entire circumference at the edge thereof. Since heat is not well transferred from the inside to the outside of the outer wall surface of the annular ridge, the effective thermal capacity during welding is mostly determined by the structure of the area inside the outer wall surface of the annular ridge. Consequently, the effective thermal capacity is nearly uniform independent of direction. Thus, it is possible to provide a sealed battery, a manufacturing method thereof, and vehicles and machinery in which the same is installed, wherein the opening can be closed under consistent welding conditions around the entire circumference.