Button Cell Terminal Structure for Swelling-Tolerant Welding
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Solution Overview
Problem
In silver oxide cells, the caulking process generates stress on the cathode can, leading to swelling, which can result in inadequate welding of terminals due to gaps between the cathode can and terminals, compromising the welding strength.
Innovation Solution
A terminal-equipped button cell design featuring a cathode can with a curved convex bottom surface and a cathode terminal with a flat connecting part disposed along the radial direction, fixed to the bottom surface at an angle to form a tangent line, ensuring secure contact and connection without gaps, and employing multiple welded points between the center and rim of the cathode can, with a thickness of 0.07 to 0.15 mm for enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the cathode can is strongly caulked to prevent leakage and increase filling rate, then the discharge capacity is improved, but the cathode can becomes swollen and welding quality deteriorates
Solution Approach 1:
The cathode terminal is pre-formed with a curved bottom surface that matches the expected swelling shape of the cathode can. This preliminary shaping ensures that even after strong caulking causes swelling, the terminal maintains proper contact with the cathode can bottom surface, preventing gaps and ensuring good welding quality while allowing strong caulking for high discharge capacity
Solution Approach 2:
The invention changes the geometric parameters of the cathode terminal, specifically forming its bottom surface with a curvature radius of 3mm to 10mm to match the swelling characteristics of the cathode can. This parameter adjustment allows the terminal to adapt to the swollen shape, maintaining welding quality even when strong caulking is applied to increase discharge capacity
2Quantity of substance
If the cathode can is strongly caulked during assembly, then the filling rate of active material and electrolytic solution is increased, but stress is generated and the cathode can is swollen in the vicinity of the center
Solution Approach 1:
The cathode terminal is pre-formed with a curved bottom surface that anticipates the swelling that will occur during strong caulking. This preliminary shaping allows the terminal to maintain proper contact with the swollen cathode can bottom surface, ensuring that the increased filling rate achieved through strong caulking does not result in gaps or poor welding quality
3Device complexity
If a flat terminal is welded to a swollen cathode can bottom surface, then the terminal structure is simple, but gaps are formed and welding strength decreases
Solution Approach 1:
The invention changes the geometric parameters of the cathode terminal by forming its bottom surface with a specific curvature radius (3mm to 10mm) that matches the swelling characteristics of the cathode can. This parameter modification allows the terminal to conform to the swollen surface, eliminating gaps and ensuring strong welding without requiring complex terminal structures or additional compensation mechanisms
Data Source
AI summary
A terminal-equipped button cell of the present invention includes: a cathode can and an anode can having flat cylindrical shapes; a gasket configured to insulate and seal the cathode can and the anode can; and a cathode terminal and an anode terminal fixed to a bottom surface of the cathode can and a bottom surface of the anode can, wherein the bottom surface of the cathode can is curved convexly and outwardly in a thickness direction by 100 μm or less while being integrated with the anode can, and the cathode terminal has a flat cathode connecting part, and the cathode terminal is disposed along a radial direction of the bottom surface of the cathode can, and the cathode connecting part is fixed to the bottom surface by being inclined so as to form a tangent line to the bottom surface at a position other than a center of the bottom surface when viewed in a sectional view following the radial direction and perpendicular to the bottom surface.