Battery Lid Inserted Portion Rounding for Foreign Matter Control
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Solution Overview
Problem
During the manufacturing of power storage devices, such as rechargeable batteries, foreign matter is developed due to the scraping of the distal end of the lid's inserted portion by the inner circumferential surface of the case body, leading to filamentary foreign matter production.
Innovation Solution
A power storage device design featuring a metal tubular case body with a closed end and a metal lid, where the lid has an inserted portion with a rounded or chamfered corner at its distal end, with the edge-removal dimension set equal to or greater than the average particle diameter of the material, preventing the development of filamentary foreign matter by removing sharp edges and ensuring the corner is softer than the case body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inserted portion of the lid is inserted into the case body during manufacturing, then the case is assembled, but the distal end of the inserted portion is scraped by the inner circumferential surface of the case body, producing filamentary foreign matter
Solution Approach 1:
The patent applies preliminary action by forming a rounded corner at the distal end of the inserted portion before assembly. This pre-processing step removes sharp edges that would otherwise cause scraping and foreign matter generation during the assembly process, thereby preventing the harmful effect before it occurs.
Solution Approach 2:
The patent applies spheroidality by rounding the corner at the distal end of the inserted portion. This curvature eliminates sharp edges that concentrate stress and cause material scraping, allowing the inserted portion to slide smoothly along the inner circumferential surface of the case body without generating filamentary foreign matter.
2Ease of manufacture
If the inner circumferential edge of the case body contacts the inserted portion during assembly, then the components are joined, but the inner circumferential edge is scraped, producing filamentary foreign matter
Solution Approach 1:
The patent applies preliminary action by forming a rounded corner at the inner circumferential edge of the case body before assembly. This pre-processing step removes sharp edges that would otherwise scrape against the inserted portion during assembly, preventing foreign matter generation at this interface.
Solution Approach 2:
The patent applies spheroidality by rounding the corner at the inner circumferential edge of the case body. This curvature creates a smooth transition surface that reduces contact stress and prevents scraping of the inserted portion, thereby eliminating the source of filamentary foreign matter.
3Ease of manufacture
If a sharp edge is present at the distal end of the inserted portion, then manufacturing is simpler, but the sharp edge causes scraping and foreign matter development during assembly
Solution Approach 1:
The patent applies preliminary action by incorporating the corner rounding step into the manufacturing process of the lid. This ensures that the inserted portion has a rounded distal end before assembly, preventing reliability issues related to foreign matter contamination while maintaining manufacturing feasibility.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the inserted portion's distal end from a sharp corner to a rounded corner with a specified radius. This parameter change eliminates the harmful sharp edge while maintaining the structural integrity and functional requirements of the component.
Data Source
AI summary
A lid of a rechargeable battery includes a lid body that closes an opening of a case body and is supported by a case-side mating surface surrounding the opening of the case body. The lid also includes an inserted portion having a shape of a quadrangular column. The inserted portion protrudes from the lid body toward an inner part of the case body and extends along an inner circumferential surface of the case body. The lid also includes a rounded corner present in the distal end of the inserted portion in a protruding direction in which the inserted portion protrudes from the lid body. The lower limit of an edge-removal dimension of the corner is equal to an average particle diameter of a material for the lid.