Battery Cell Terminal Rivet Clamping to Prevent Electrolyte Leakage
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Solution Overview
Problem
Conventional methods of riveting terminal rivets in secondary cells can cause deformation of the casing, leading to potential leakage of electrolyte due to cavities formed between components during the riveting process.
Innovation Solution
A method of riveting a terminal rivet for a cylindrical secondary cell, where the shaft is deformed against the internal surface of the casing and the head is deformed against the external surface, ensuring proper clamping and preventing leakage. The terminal rivet comprises a shaft and a head with specific deformation regions to secure the rivet in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the terminal rivet is deformed only on the inside of the casing during riveting, then the riveting process is simple, but cavities form between components causing electrolyte leakage
Solution Approach 1:
The deformation process is segmented into two distinct locations: internal deformation of the shaft against the inner casing surface and external deformation of the head against the outer casing surface. This segmentation allows each deformation zone to perform its specific function - the shaft deformation provides internal anchoring while the head deformation ensures external sealing, eliminating cavity formation and preventing electrolyte leakage.
Solution Approach 2:
The terminal rivet acts as an intermediary element between the internal components (electrode assembly, current collector) and the external environment. By deforming both the shaft internally and the head externally, the rivet mediates the sealing function, ensuring that no cavities form between components that could allow electrolyte leakage.
2Force
If the casing is deformed during external riveting pressure application, then the riveting force is effectively transmitted, but electrolyte leakage occurs due to casing deformation
Solution Approach 1:
The deformation is localized to specific regions of the terminal rivet rather than the casing itself. The shaft deforms locally against the inner casing surface at the deformation zone, while the head deforms locally against the outer casing surface. This localized deformation approach transmits riveting force effectively without causing overall casing deformation that would compromise sealing integrity.
Solution Approach 2:
Instead of deforming the casing to achieve riveting force transmission, the invention inverts the approach by deforming the terminal rivet itself. The shaft and head of the rivet are deformed against the casing surfaces, transmitting force through the rivet material rather than through casing deformation, thereby maintaining sealing integrity while achieving effective force transmission.
3Reliability
If a second deformation region is added to the head of the terminal rivet, then leakage is prevented by proper clamping, but the manufacturing process becomes more complex
Solution Approach 1:
The two deformation operations - internal shaft deformation and external head deformation - are merged into a single integrated riveting process. Both deformation zones of the terminal rivet are activated simultaneously or in sequence during one riveting operation, achieving leakage prevention through proper clamping without significantly increasing manufacturing process complexity.
Solution Approach 2:
The terminal rivet structure itself provides the solution for leakage prevention. The shaft and head are designed with specific deformation zones that automatically engage with the inner and outer casing surfaces respectively during riveting. The rivet serves itself by using its own material deformation to create the clamping force needed for sealing, eliminating the need for additional external sealing components or complex multi-step processes.
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
The described method effectively prevents leakage by ensuring the terminal rivet is properly clamped to the casing, enhancing the reliability and manufacturing efficiency of secondary cells.
Implementation Method 1
deforming the shaft against an internal surface of the casing
Implementation Method 2
deforming the head against the external surface of the casing towards the deformed shaft
Data Source
AI summary
There is disclosed herein a method for riveting a terminal rivet for a cylindrical secondary cell, wherein the terminal rivet comprises a head and a shaft extending from the head. The method comprises the steps of arranging the shaft of the terminal rivet axially through an opening in a casing of the secondary cell such that the head of the terminal rivet abuts an external surface of the casing to thereby form an external terminal for the secondary cell. The method further comprises the step of deforming the shaft against an internal surface of the casing, and deforming the head against the external surface of the casing towards the deformed shaft.