Battery Cell Casing Rounded-Corner Geometry for Crack-Free Forming
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Solution Overview
Problem
The existing battery cell cases are prone to wrinkling and cracking during the integral forming process due to material accumulation at rounded corners, which affects the performance and increases manufacturing difficulty.
Innovation Solution
The case design incorporates specific dimensions for the depth and inner diameter of rounded corners (2.5 mm≤R1≤20 mm and 50 mm≤H≤250 mm) and materials like stainless steel or carbon steel with appropriate yield strength (140 MPa≤Re≤1000 MPa) to reduce stress-related cracking and improve forming ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case is integrally formed with rounded corners, then the structural integrity is improved, but material accumulation at rounded corners causes wrinkling and cracking
Solution Approach 1:
The patent applies parameter changes by optimizing the rounded corner radius (R1) to be within 2.5-20mm and case depth (H) to be within 50-250mm. These specific parameter ranges control material flow during forming, preventing both material accumulation that causes wrinkling and excessive stress that causes cracking, while maintaining structural integrity.
2Quantity of substance
If the case depth H is increased to maintain energy density, then the battery capacity is improved, but the risk of cracking during forming increases
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range where case depth H is limited to 50-250mm. This parameter control ensures sufficient battery capacity while preventing excessive stress concentration during integral forming that would lead to cracking, particularly at rounded corner regions.
3Strength
If the yield strength Re is increased to prevent stress deformation, then the case strength is improved, but the forming difficulty increases
Solution Approach 1:
The patent applies parameter changes by optimizing the yield strength Re to be within 140-1000 MPa. This range ensures the case has sufficient strength to resist stress deformation during use while remaining formable through integral forming processes without excessive difficulty.
4Manufacturing precision
If the rounded corner inner diameter R1 is decreased to reduce material accumulation, then the wrinkling risk is reduced, but the stress concentration increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the rounded corner inner diameter R1 to be within 2.5-20mm. This parameter range is carefully selected to balance two opposing effects: small enough to reduce material accumulation and wrinkling, but large enough to avoid excessive stress concentration that would cause cracking during forming.
Data Source
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AI summary
Embodiments of the present application provide a case, a battery cell, a battery, and a power consuming apparatus. The case has an opening, and the case is of an integrally formed structure. The case includes a first wall and at least two second walls opposite to the opening. The first wall and the second walls intersect with each other. Two of the at least two second walls are connected by using a first rounded corner. An inner diameter R1 of the first rounded corner and a depth H of the case satisfy: 2.5 mm≤R1≤20 mm and 50 mm≤H≤250 mm. According to the case, the battery cell, the battery, and the power consuming apparatus in the embodiments of the present application, the problem of wrinkling and cracking of the case caused by material accumulation at the rounded corner can be reduced in a process of integrally forming the case.