Cylindrical Battery Terminal Sealing Structure to Prevent Leakage
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Solution Overview
Problem
Cylindrical secondary batteries with positive electrode terminals on one side face issues of incomplete sealing due to gaps between the terminal and insulator, leading to electrolyte leakage, and are prone to rotation from external forces due to a lack of sufficient coupling strength.
Innovation Solution
A cylindrical secondary battery design featuring a coupling groove and protrusion adjacent to the terminal hole, with a depth 10-30% smaller than the can's thickness, and an insulator with a coupling portion to enhance sealing and coupling strength, preventing electrolyte leakage and terminal rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple terminal structure is used with a terminal hole and insulator, then the electrical connection structure is simple, but the sealing force is insufficient causing electrolyte leakage
Solution Approach 1:
The terminal structure is segmented into multiple functional components: the insulator body, the coupling groove, and the coupling protrusion. This segmentation allows each component to perform its specific function - the insulator provides electrical insulation, the coupling groove receives the protrusion to create a mechanical interlock, and together they form a sealed connection that prevents electrolyte leakage while maintaining simple electrical connectivity.
2Ease of manufacture
If a simple terminal structure is used without coupling features, then the manufacturing process is simple, but the coupling strength is insufficient causing terminal rotation
Solution Approach 1:
The coupling groove and coupling protrusion are pre-formed during the can manufacturing process before final assembly. This preliminary action ensures that when the insulator is installed, the mechanical interlock is already in place, providing immediate coupling strength to prevent terminal rotation without requiring additional manufacturing steps or complex assembly procedures.
3Strength
If the coupling groove depth is equal to the can thickness, then the coupling strength is maximized, but the insulator cannot be properly positioned and sealing is compromised
Solution Approach 1:
The depth of the coupling groove is optimized to a specific parameter range that is less than the full can thickness. This parameter change allows the groove to provide sufficient coupling strength for preventing terminal rotation while leaving enough material above the groove to ensure proper insulator positioning and maintain the sealing function. The specific depth parameter balances mechanical strength with positioning precision.
Data Source
AI summary
A cylindrical secondary battery includes: an electrode assembly; a cylindrical can accommodating the electrode assembly and having a terminal hole at a first end; and a terminal portion coupled to the first end of the can and electrically connected to the electrode assembly, and the can further includes a coupling groove and a coupling protrusion adjacent to the terminal hole on a portion through which the terminal hole passes. In the cylindrical secondary battery according to embodiments of the present disclosure, a sealing force of the cylindrical secondary battery may be increased by providing a groove and a protrusion in the can that is a region to which a rivet terminal is coupled.