Cylindrical Battery Cap Plate Geometry for Stable Weld Height
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Solution Overview
Problem
Existing technologies have not adequately addressed the challenges of ensuring stable and efficient welding of secondary batteries, particularly in ensuring weld heights of adjacent secondary batteries, particularly in ensuring consistent weld heights and preventing deformation under increased internal pressure while facilitating gas release.
Innovation Solution
A secondary battery design featuring a cylindrical case with a cap plate having a first flat portion and a second flat portion, where the first flat portion is inclined inward in the radial direction, and a connecting portion, and the second flat portion is positioned inward in the radial direction, and a connecting portion, and a connecting portion, and the second flat portion is positioned inward in the radial direction, and a connecting portion, and the second flat portion is positioned inward in the radial direction, and the second flat portion is positioned inward in the radial direction, and the second flat portion is positioned inward in the radial direction, and the second flat portion is positioned inward in the radial direction, and the second flat portion is positioned inward in the radial direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cap plate is designed with a single flat surface, then the manufacturing process is simple, but the welding consistency and deformation prevention are insufficient
Solution Approach 1:
The cap plate is divided into multiple functional regions: a first flat portion for welding external tabs, a second flat portion for welding electrode tabs, and a connecting portion linking them. This segmentation allows each region to be optimized for its specific function, ensuring consistent weld heights while maintaining manufacturing feasibility.
Solution Approach 2:
Different portions of the cap plate are designed with different local characteristics. The first flat portion has a specific height for external tab welding, the second flat portion has a different height for electrode tab welding, and the connecting portion has an inclined surface. This local differentiation enables precise control of weld heights in different areas while preventing deformation under internal pressure.
2Strength
If the cap plate structure is simplified, then the manufacturing is easier, but the ability to prevent deformation under increased internal pressure is reduced
Solution Approach 1:
The connecting portion is designed with an inclined surface that can deform in a controlled manner under increased internal pressure. This dynamic design allows the cap plate to accommodate pressure changes while maintaining structural integrity and preventing catastrophic deformation, balancing strength requirements with manufacturing simplicity.
3Reliability
If the cap plate has a uniform height structure, then the manufacturing is simpler, but the gas release capability is insufficient
Solution Approach 1:
The cap plate employs an asymmetric height structure where the first flat portion, second flat portion, and connecting portion have different heights and orientations. This asymmetric design creates pathways for gas release while maintaining the sealing function, enabling the cap plate to perform multiple functions without requiring additional complex components.
Data Source
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AI summary
A secondary battery includes a cylindrical case, an electrode assembly accommodated in the cylindrical case, and a cap plate electrically connected to the electrode assembly and configured to seal the cylindrical case, wherein the cap plate includes a first flat portion at a center thereof, a second flat portion outside the first flat portion, and a connecting portion between the first flat portion and the second flat portion, and wherein a height of a top surface of the first flat portion is higher than a height of a top surface of the second flat portion.