Sealed Battery Welding Position to Prevent Blowholes
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Solution Overview
Problem
Conventional sealed batteries experience blowholes during welding due to gas entrapment in the welding atmosphere, leading to airtightness and compressive strength issues.
Innovation Solution
The sealed battery design includes an outer packaging body with an internal space filled with inert gas, where the welding portion is positioned higher than the uppermost part of the internal space, ensuring the inert gas is retained and preventing gas entrapment during welding, and the manufacturing method involves injecting electrolyte and inert gas followed by welding the cover at a position higher than the internal space opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed to join the sealing cap to the housing, then the sealing cap is securely fixed to the housing, but gas inside the housing is heated and expands, causing blowholes in the welding portion
Solution Approach 1:
The sealing cap is designed with a bent central part that projects outside the housing before welding. This preliminary configuration allows the welding portion to be positioned such that gas expansion during welding does not get trapped, preventing blowholes while maintaining welding strength
Solution Approach 2:
The welding portion is positioned at a specific location on the sealing cap where the bent central part creates sufficient distance from the housing interior. This parameter change in positioning ensures that even when gas expands due to welding heat, it cannot reach and trap in the welding portion, thus preventing blowholes
2Manufacturing precision
If the sealing cap is designed with a bent central part projecting outside the housing, then blowholes are prevented during welding, but the structural complexity of the sealing cap increases
Solution Approach 1:
The sealing cap is segmented into distinct functional parts: a peripheral part for joining to the housing and a central part that bends to project outside. This segmentation allows each part to perform its specific function independently, with the bent central part serving solely to position the welding portion to prevent blowholes
3Reliability
If the welding portion is positioned to prevent gas entrapment, then blowholes are restrained, but the welding position requirements become more stringent
Solution Approach 1:
The bent central part of the sealing cap automatically positions the welding portion at an optimal location that prevents gas entrapment during welding. This self-positioning feature eliminates the need for complex external positioning mechanisms or stringent welding process controls, thereby maintaining welding reliability while simplifying the manufacturing process
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 configuration effectively prevents blowholes in the welding portion, enhancing airtightness and compressive strength by maintaining inert gas in the uppermost part of the internal space during welding.
Implementation Method 1
the inert gas is retained in the uppermost part of the internal space at the time of welding of the outer packaging body and the cover
Implementation Method 2
a welding portion provided on a boundary between the outer packaging body and the cover, the welding portion being configured to join the outer packaging body to the cover
Data Source
AI summary
A sealed battery includes an outer packaging body, a cover, and a welding portion. The outer packaging body has an internal space, and the internal space includes inert gas. The outer packaging body has an opening communicating with the internal space. The cover is configured to close the opening and to seal the internal space. The welding portion is provided on a boundary between the outer packaging body and the cover, and joins the outer packaging body to the cover. The welding portion is provided at a position higher than an uppermost part of the internal space in a state where the opening is opened in a vertically upward direction from the internal space toward an outside of the outer packaging body.