Battery Case Curvature Layout for Uniform Thin-Wall Cells
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Solution Overview
Problem
Conventional battery can manufacturing methods face limitations in achieving reduced thickness with minimal thickness deviation, high dimensional accuracy, and improved strength and cooling efficiency, particularly in the cell bottom and side portions.
Innovation Solution
The secondary battery design incorporates a case with specific bent portions having varying radii of curvature and widths, including a gradual increase in curvature and width away from the bottom portion, along with a welding portion to connect side portions, enhancing structural integrity and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deep drawing method or impact method is used to manufacture battery can, then manufacturing process is completed, but thickness of can varies greatly depending on area and manufacturing cost is high
Solution Approach 1:
The patent applies parameter changes by varying the radius of curvature along the side bent portion (increasing from bottom to top) and adjusting the width of side bent portions to optimize both thickness uniformity and manufacturing efficiency. This gradual parameter change reduces stress concentration and minimizes thickness variation during the bending process.
Solution Approach 2:
The patent utilizes curvature by designing side bent portions with specific radii of curvature that increase from the bottom portion upward. This curved geometry distributes stress more evenly during forming, reducing thickness variation and improving manufacturing precision while maintaining ease of production.
2Manufacturing precision
If conventional manufacturing methods are used, then battery can is formed, but thickness of can varies greatly depending on area
Solution Approach 1:
The patent applies local quality by designing different regions of the battery can with different geometric characteristics. Specifically, the side bent portions have varying widths and radii of curvature depending on their position (long side versus short side, bottom versus top), allowing each region to be optimized for its specific structural requirements and minimizing thickness variation locally.
Solution Approach 2:
The patent uses curvature to improve dimensional accuracy by designing side bent portions with controlled radii of curvature. The gradual increase in radius from bottom to top reduces stress concentration and prevents excessive thinning in critical areas, thereby improving overall thickness distribution and dimensional accuracy.
3Ease of manufacture
If side bent portions have constant radius of curvature, then manufacturing is simplified, but spring-back phenomena occurs and welding failures increase
Solution Approach 1:
The patent applies parameter changes by progressively increasing the radius of curvature of side bent portions from the bottom portion upward. This gradual parameter transition reduces spring-back phenomena during forming and minimizes stress concentration at bends, thereby improving welding quality and reducing welding failures while maintaining manufacturing feasibility.
Data Source
AI summary
The present invention relates to a secondary battery, and the technical problem to be solved is to provide a secondary battery having the reduced thickness, having no thickness deviation by regions due to high dimensional accuracy, and being capable of improving the strength of a cell bottom portion and cell side portions (a long side portion and a short side portion) and the cooling efficiency. To this end, disclosed is a secondary battery comprising: an electrode assembly; a case in which the electrode assembly is accommodated; and a cap assembly coupled to the case for sealing the case. The case comprises a bottom portion, a long side portion bent and extending from the bottom portion, a short side portion bent and extending from the long side portion, and a side bent portion provided between the long side portion and the short side portion, wherein the side bent portion has a radius of curvature increasing as it goes farther away from the bottom portion.