Flat Battery Seal Can Geometry for Capacity and Sealability
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Solution Overview
Problem
Existing flat batteries face a challenge in increasing their internal volume to enhance battery capacity while maintaining good sealability.
Innovation Solution
The flat battery design incorporates an exterior can and a seal can with a gasket in between, featuring a peripheral wall with a cylindrical portion inclined radially outwardly and a base-end portion inclined radially inwardly, allowing for increased internal volume and capacity while maintaining sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral portion of the seal plate is folded back to improve sealability, then sealability is improved, but the internal volume of the battery is limited, preventing an increase in battery capacity
Solution Approach 1:
The peripheral wall is divided into three distinct portions: a base-end portion, a cylindrical portion, and a stepped portion. This segmentation allows each portion to serve a specific function - the base-end portion provides sealing contact, the cylindrical portion maintains structural integrity, and the stepped portion creates a seal interface - while collectively preserving internal volume by avoiding the need to fold the entire peripheral wall.
Solution Approach 2:
The peripheral wall is designed with radial inclination angles rather than simple axial folding. The base-end portion is inclined radially inwardly and the cylindrical portion is inclined radially outwardly, creating a stepped configuration that achieves sealing through dimensional variation in the radial direction while preserving axial space for battery capacity.
2Volume of stationary object
If the peripheral wall is made thinner to increase internal volume, then internal volume increases, but sealability deteriorates
Solution Approach 1:
The peripheral wall exhibits local quality variations through its stepped configuration. The base-end portion has a specific thickness optimized for sealing contact, while the cylindrical portion has adequate thickness for structural support. This localized differentiation allows the wall to be thin overall (preserving volume) while having sufficient thickness at critical sealing locations (maintaining sealability).
Data Source
AI summary
A flat battery includes an exterior can, a seal can, and a gasket. The peripheral wall includes: a base-end portion adjacent to the top-face portion; a cylindrical portion having an outer diameter larger than the outer diameter of the base-end portion and having an extreme edge facing the bottom of the exterior can; and a stepped portion located between the base-end portion and the cylindrical portion. The cylindrical portion is inclined radially outwardly going from its end adjacent to the stepped portion toward the extreme edge of the cylindrical portion and having an angle of inclination of 0.5° to 4° relative to the axial direction. The base-end portion is inclined radially inwardly going from its end adjacent to the top-face portion toward its end adjacent to the stepped portion and having an angle of inclination of 0.5° to 5° relative to the axial direction.