Battery Cell Case 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 their performance and increases manufacturing difficulty.
Innovation Solution
The case design incorporates specific dimensions for the inner diameter and depth 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 minimize stress-induced cracking and facilitate processing.
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 2.5-20 mm and case depth (H) to be within 50-250 mm. These specific parameter ranges control material flow during forming, preventing both material accumulation that causes wrinkling and stress concentration that causes cracking, while maintaining structural integrity.
Solution Approach 2:
The patent uses spheroidality by incorporating rounded corners with controlled radius instead of sharp corners. The curved geometry distributes stress more evenly during integral forming, preventing material accumulation and reducing the risk of cracking while maintaining overall structural strength.
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 range for case depth H (50-250 mm) and rounded corner radius R1 (2.5-20 mm). Within these parameter ranges, the case can achieve sufficient depth for energy density while the controlled corner radius prevents stress concentration and material accumulation, thereby avoiding cracking.
3Strength
If the yield strength Re is increased to prevent stress deformation, then the structural stability is improved, but the forming difficulty increases
Solution Approach 1:
The patent applies parameter changes by optimizing the rounded corner radius R1 to within 2.5-20 mm. This controlled curvature reduces the flowing stress required during forming, making it easier to manufacture cases with high yield strength (140-1000 MPa) without causing deformation or cracking.
Data Source
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.