Cylindrical Battery Assembly with Screw Engagement Sealing
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Solution Overview
Problem
Conventional cylindrical can type secondary batteries face issues with bead deformation and the presence of unnecessary gaps between the electrode assembly and the cap unit, leading to compromised sealing reliability and reduced battery capacity due to high pressure clamping, which can cause air or humidity leakage and affect manufacturing processes.
Innovation Solution
The solution involves forming upper and lower battery assemblies with screw or sleeve engagement, eliminating the need for beads by using a gasket and cap unit assembly that ensures robust clamping without deformation, allowing for efficient sealing and increased battery capacity while minimizing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure clamping is applied to seal the battery, then sealing reliability is improved, but bead deformation occurs causing air or humidity leakage
Solution Approach 1:
The battery is divided into upper and lower battery assemblies that are separately manufactured and then combined through screw engagement. This segmentation eliminates the need for beads in the sealing structure, allowing high pressure clamping to be applied without causing bead deformation and leakage.
Solution Approach 2:
The upper and lower battery assemblies are pre-assembled with their respective sealing structures (gaskets) before final combination. The screw threads are pre-formed on the cans, and gaskets are pre-installed, enabling the sealing function to be achieved without deformation during the clamping process.
2Device complexity
If beads are used for sealing, then sealing structure is simplified, but deformation occurs reducing battery capacity
Solution Approach 1:
The battery is segmented into upper and lower assemblies with separate sealing structures (gaskets). This eliminates the need for beads while maintaining sealing functionality, thereby increasing the active material volume and battery capacity without complicating the sealing structure.
3Quantity of substance
If gap between electrode assembly and cap unit is reduced, then battery capacity is improved, but sealing reliability may be compromised
Solution Approach 1:
The battery is divided into upper and lower assemblies with dedicated sealing interfaces. The screw engagement creates a robust sealing connection between assemblies, allowing the gap within each assembly to be minimized for capacity while maintaining sealing integrity through the separate assembly interface.
Solution Approach 2:
Gaskets are used as intermediary sealing elements at the interface between upper and lower battery assemblies. These gaskets provide reliable sealing at the assembly interface, enabling minimal gaps within assemblies to maximize capacity while maintaining overall sealing reliability.
Data Source
AI summary
A secondary battery having an upper battery assembly including an upper can housing a cap unit having an electrode terminal adapted to electrically connect to an external device and a gasket inserted between the cap unit and one end portion of the upper can for sealing and insulating the cap unit and the upper can. The secondary battery also has a lower battery assembly including a lower can housing an electrode assembly, the electrode assembly having a first electrode, a second electrode, and a separator interposed between the first electrode for preventing a short circuit between the two electrodes. A first electrode tap connects the first electrode to the cap unit and a second electrode tap connects the second electrode to the lower can.