Cylindrical Battery Rivet Terminal Structure to Prevent Rotation
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Solution Overview
Problem
Cylindrical secondary batteries with rivet-type terminals face issues of terminal rotation due to external forces or vibrations, complicating the battery module structure and extending manufacturing times, necessitating a solution to prevent such rotation.
Innovation Solution
Incorporating a rotation prevention structure on the can and rivet terminal, including laser-engraved patterns and protrusions/grooves, to securely fasten the rivet terminal and prevent movement, with insulators for electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rivet-type terminal is used to simplify battery module structure, then device complexity is reduced, but the terminal may rotate due to external force or vibration, worsening reliability
Solution Approach 1:
The patent introduces asymmetric features including a non-circular terminal hole shape (square, rectangular, or polygonal cross-section) and corresponding asymmetric protrusions on the rivet terminal. This asymmetric design prevents rotational movement of the terminal while maintaining structural simplicity, thereby resolving the contradiction between device complexity and reliability.
Solution Approach 2:
The patent incorporates rotation preventing portions (protrusions and grooves) that are pre-formed on the rivet terminal and cannelure surface before assembly. These features are built-in during manufacturing, preventing rotation before it can occur during operation, thus maintaining both simplicity and reliability.
2Productivity
If a rivet-type terminal is used to reduce manufacturing process time, then productivity is improved, but the terminal may rotate due to external force or vibration, worsening reliability
Solution Approach 1:
The asymmetric terminal hole design and corresponding protrusions are integrated into the rivet terminal structure, allowing for a single-step insertion and fixation process. This eliminates the need for additional rotation-prevention steps, maintaining high productivity while ensuring reliability through the asymmetric anti-rotation mechanism.
Solution Approach 2:
The patent combines the terminal function and rotation prevention function into a single integrated rivet terminal structure. The protrusions are formed as part of the terminal body, merging two functions (electrical connection and rotation prevention) into one component, thereby maintaining manufacturing efficiency while improving reliability.
3Reliability
If frictional forces are increased to prevent terminal rotation, then reliability is improved, but the manufacturing precision requirements increase, worsening manufacturing precision
Solution Approach 1:
The protrusions and grooves are pre-formed during the rivet terminal manufacturing process using standard forming techniques. This preliminary action ensures that the anti-rotation features are already in place before assembly, reducing the precision requirements during the final assembly operation and making the process more robust to manufacturing variations.
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 solution effectively prevents terminal rotation, enhancing the stability and reliability of the secondary battery by increasing frictional forces and ensuring secure terminal connection, thus simplifying the battery module structure and reducing manufacturing time.
Implementation Method 1
The solution effectively prevents terminal rotation, enhancing the stability and reliability of the secondary battery by increasing frictional forces
Data Source
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AI summary
A cylindrical secondary battery includes an electrode assembly; a cylindrical can accommodating the electrode assembly; and a terminal portion including a rivet terminal coupled to one side in the longitudinal direction of the can and electrically connected to the electrode assembly and at least one insulator between the can and the rivet terminal to insulate the can and the rivet terminal from each other. The battery also includes a rotation preventing portion on the can and/or the terminal portion. Since a structure for preventing rotation of the rivet terminal is provided on the upper surface of the can or the rivet head or the main body to which the rivet terminal is fastened, the rivet terminal may not rotate due to an external force or vibration. Therefore, the stability and reliability of the secondary battery can be improved.