Flat Battery Gasket Thickness Gradient Absorbs Compression
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Solution Overview
Problem
In flat batteries, the gasket molded on the seal can tends to exfoliate from the inner surface, leading to potential short circuits or damage to the electrode assembly due to uneven compression forces, especially when the gasket thickness varies along its length.
Innovation Solution
A gasket is molded on the inner surface of the seal can, extending from the opening edge to the flat portion, with a stepped portion on the cylinder portion to absorb compression forces, ensuring a smaller thickness near the opening edge to prevent exfoliation and a tapered design to improve workability and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stepped portion is formed on the peripheral wall of the seal can to increase interior volume and improve sealing, then sealing performance is improved, but a very large compression force is applied to the gasket causing it to exfoliate
Solution Approach 1:
The gasket is designed with variable thickness along its length, with the thickest portion located at the stepped portion where compression force is applied. This local variation in thickness provides enhanced mechanical strength and adhesion capacity precisely where the compression force from the stepped portion acts, preventing exfoliation while maintaining the sealing benefits of the stepped structure.
2Reliability
If a gasket of resin is molded around the peripheral wall of the seal can, then air tightness is maintained and electrical isolation is ensured, but the gasket may exfoliate from the inner surface due to compression force
Solution Approach 1:
The gasket features a thickness gradient along its length, with the maximum thickness positioned at the stepped portion where compression force is concentrated. This local thickening provides enhanced structural integrity and adhesion strength precisely where needed to resist the compression force, while maintaining the essential functions of air tightness and electrical isolation throughout the gasket's entire structure.
3Ease of manufacture
If the opening edge portions of the peripheral wall are shaped as a simple plate, then manufacturing is simpler, but sealing is relatively weak providing only small compression force
Solution Approach 1:
The peripheral wall structure is segmented into two distinct portions: a simple plate opening edge portion for manufacturing simplicity, and a stepped portion that provides enhanced sealing through increased compression force. This segmentation allows each portion to fulfill its specific function optimally while working together as an integrated structure.
Data Source
AI summary
Provided is a flat battery with a molded gasket extending from the opening edge of the seal can to the flat portion, where the gasket may be prevented from exfoliating from the inner surface of the seal can. A flat battery (1) includes: a negative electrode can (10) (exterior can) shaped as a cylinder with a bottom; a positive electrode can (20) (seal can) having a peripheral wall (22) (cylinder portion) and a flat portion (21), the positive electrode can being disposed as an inverted dish with respect to the negative electrode can (10); and a gasket (30) molded at least on an inner surface of the positive electrode can (20), extending from the opening edge of the peripheral wall (22) to the flat portion (21). The opening edge of the sidewall of the negative electrode can (10) is fitted onto the stepped portion (22c) of the positive electrode can (20), and a portion of the gasket (30) that is located inside the opening edge portion of the peripheral wall (22) of the positive electrode can (20) with respect to the positive electrode can has a thickness smaller than that of a portion of the gasket that is located inside the stepped portion (22c) of the positive electrode can (20) with respect to the positive electrode can.