Prismatic Battery Laser Welding for Sealing Strength
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Solution Overview
Problem
The challenge is to ensure a prescribed welding strength in square batteries as the reduction in battery container thickness narrows the welding allowable range, and variations in precision can lead to weakened welds when the battery lid is welded beyond the container's thickness.
Innovation Solution
A square battery design where the battery lid is welded to the battery can with both lateral and vertical boundary surfaces, using laser radiation along the height direction to form a welding portion that secures the space between the two components, ensuring a stable welding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the plate thickness of the battery can is reduced to make the battery small-sized and light-weighted, then the weight and size of the battery are reduced, but the welding allowable range is narrowed making it difficult to ensure predetermined welding strength
Solution Approach 1:
The invention transitions from a single-direction welding approach to a multi-dimensional welding structure by forming both lateral boundary surfaces and vertical boundary surfaces. The lateral boundary surfaces extend in the horizontal direction while the vertical boundary surfaces extend in the vertical direction, creating a three-dimensional welding geometry that distributes welding stress and ensures adequate welding strength even with reduced plate thickness.
Solution Approach 2:
The welding structure is segmented into multiple boundary surfaces (lateral and vertical) rather than relying on a single welding zone. This segmentation allows the welding load to be distributed across multiple surfaces, compensating for the reduced welding allowable range caused by thinner plate material.
2Manufacturing precision
If the battery lid is welded beyond the range of the plate thickness due to variation in precision, then the welding process becomes more difficult, but the welding allowable range is further narrowed
Solution Approach 1:
The invention changes the welding parameters by creating a multi-faceted welding structure with both lateral and vertical boundary surfaces. This geometric parameter change provides a larger effective welding area and more flexible welding zone, accommodating variations in manufacturing precision while maintaining adequate welding strength.
Solution Approach 2:
By introducing vertical boundary surfaces in addition to lateral boundary surfaces, the invention adds a vertical dimension to the welding structure. This dimensional expansion provides tolerance for precision variations and ensures that the welding zone remains within the allowable range even when manufacturing variations occur.
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 a high and consistent welding strength, resisting forces from internal pressure and deformation, while simplifying manufacturing by reducing the risk of welding quality variations due to dimensional tolerances.
Implementation Method 1
at least a part of the lateral boundary surface and at least a part of the vertical boundary surface being welded by a laser radiated in the vertical direction along the height direction of the side wall portions
Data Source
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AI summary
An object of the present invention is to obtain a square battery in which a welding portion which welds a battery can and a battery lid can ensure a prescribed welding strength. A square battery (1) of the present invention includes a battery can (100) surrounded by four side wall portions, and having an upper end portion on one side in a height direction of the side wall portions opened and having a bottom portion in a lower end portion on the other side in the height direction, and a battery lid (200) welded to the upper end portion of the battery can to seal the battery can, wherein between the battery can and the battery lid, a lateral boundary surface (Fx) in a lateral direction crossing the height direction of the side wall portions and a vertical boundary surface (Fy) in a vertical direction crossing the lateral boundary surface and along the height direction of the side wall portions are formed, at least a part of the lateral boundary surface and at least a part of the vertical boundary surface being welded by a laser (EB) radiated in the vertical direction along the height direction of the side wall portions.