Secondary Battery Insulator Protrusions for Cap Assembly Stability
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Solution Overview
Problem
Secondary batteries face issues with limited coupling force between the insulator, vent plate, and cap-down due to interference, leading to potential dislodgment under vibration or shock, which can break the weld and disrupt the current path, affecting battery operation.
Innovation Solution
The design incorporates a cap assembly with a vent plate, an insulator featuring protrusions or step areas, and a cap-down with corresponding grooves or holes, enhancing the coupling force through increased surface friction and secure fastening, preventing rotation and dislodgment during vibrations or shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the first fastening member size is increased to improve coupling force, then the coupling force increases, but the interference with bent portions of the vent plate increases, preventing further size increase
Solution Approach 1:
The insulator is divided into multiple segments or sections, each with its own fastening members. This segmentation allows the fastening members to be distributed across different locations, reducing the size requirement for each individual member while maintaining overall coupling force through multiple attachment points.
Solution Approach 2:
The fastening members are designed with a nested structure where smaller fastening members are positioned within or alongside larger structural elements of the insulator. This nesting allows the fastening members to be compact while still providing sufficient coupling force, avoiding interference with the vent plate's bent portions.
2Reliability
If the insulator and cap-down are coupled by second fastening members that vertically press the cap-down, then the coupling is secured, but the cap-down may rotate due to vibration or shock
Solution Approach 1:
The second fastening members are designed with asymmetric features such as non-circular cross-sections or offset positioning. This asymmetry prevents rotational movement of the cap-down by creating a mechanical keyway effect, where the asymmetric shape of the fastening member does not align with rotational symmetry, thereby preventing rotation under vibration or shock.
Solution Approach 2:
The fastening members incorporate curved or rounded surfaces that engage with corresponding curved features on the cap-down. This curvature design allows the fastening members to press vertically while also providing rotational resistance through the geometric interlocking of curved surfaces, preventing the cap-down from rotating during operation.
3Force
If the cap-down rotates due to vibration or shock, then the coupling force is maintained initially, but the weld between vent and cap-down breaks, blocking the current path
Solution Approach 1:
The insulator design incorporates preliminary anti-rotation features such as protrusions, ribs, or asymmetric fastening members that actively prevent rotation before it can occur. These features create mechanical constraints that counteract the rotational forces generated by vibration or shock, protecting the weld between the vent and cap-down from breaking by preventing the rotational motion that would cause such damage.
Data Source
AI summary
There is a provided a secondary battery capable of preventing unloading and rotating caused by possible vibration or shock by increasing a coupling force among the vent plate, the insulator, and the cap-down that compose the cap assembly of the secondary battery. To increase the coupling force among the vent plate, the insulator, and the cap-down, protrusions and corresponding grooves or holes, and grooves with step areas may be formed. Alternatively, a plurality of insulators may be formed in a divided form. A secondary battery with a reliable cap assembly can be implemented through such a structural change.