Cylindrical Battery Crimp Structure for Controlled Notch Rupture
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Solution Overview
Problem
Existing cylindrical secondary batteries face challenges in precisely controlling the notch rupture pressure and uncrimping pressure, leading to potential uncrimping before notch rupture, which can compromise safety and increase material costs.
Innovation Solution
A cylindrical secondary battery design with a cap plate having a notch with a lower rupture pressure than the uncrimping pressure of the crimping portion, utilizing an insulating gasket and specific dimensions and materials to optimize the overlap length, thickness, and stiffness of the crimping portion to prevent uncrimping before notch rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crimping portion is designed with sufficient overlap length and thickness to prevent uncrimping, then the structural integrity is improved, but the manufacturing cost increases and the design precision of rupture pressure becomes difficult to control
Solution Approach 1:
The patent optimizes specific parameters of the crimping portion including overlap length (0.5-3.0 mm), thickness (0.3-0.8 mm), and bending radius (0.2-0.5 mm) to achieve the desired balance between preventing uncrimping and controlling notch rupture pressure. By precisely controlling these dimensional parameters, the design ensures that the crimping portion maintains sufficient strength while allowing the notch to rupture at the intended pressure threshold.
Solution Approach 2:
The patent applies different properties to different regions of the cap plate structure. The crimping portion is designed with specific local characteristics (overlap length, thickness, bending radius) that differ from the main body of the cap plate. This local differentiation allows the crimping portion to provide enhanced structural integrity where needed while maintaining overall control over the rupture pressure characteristics of the notch.
2Reliability
If the overlap length of the crimping portion is increased to prevent uncrimping, then the reliability is improved, but the material cost increases
Solution Approach 1:
The patent establishes an optimal range for the overlap length of the crimping portion (0.5-3.0 mm) that provides sufficient reliability to prevent uncrimping while minimizing material consumption. This parameter optimization ensures that the crimping portion has just enough overlap to maintain structural integrity without excessive material usage, thereby controlling costs while achieving the desired reliability level.
Solution Approach 2:
The patent employs a thin-walled can structure with controlled crimping portion thickness (0.3-0.8 mm) that provides sufficient mechanical strength through optimized geometry rather than increased material thickness. This approach allows the use of thinner, more cost-effective materials while maintaining the necessary reliability through precise dimensional control of the crimping features.
3Strength
If the crimping portion thickness is increased to prevent uncrimping, then the strength is improved, but the manufacturing precision of rupture pressure control deteriorates
Solution Approach 1:
The patent specifies an optimal thickness range for the crimping portion (0.3-0.8 mm) that balances structural strength with rupture pressure control precision. By controlling the thickness within this range, the design ensures that the crimping portion is strong enough to prevent uncrimping under normal conditions while allowing the notch to rupture at the intended pressure threshold with sufficient precision.
Solution Approach 2:
The patent applies localized quality enhancements to the crimping portion through specific dimensional controls (thickness, overlap length, bending radius) that differ from the main can body. This localized optimization provides the necessary strength at the crimping region without affecting the overall rupture pressure characteristics of the notch, maintaining manufacturing precision while ensuring structural integrity.
Data Source
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AI summary
Disclosed is a cylindrical secondary battery including an electrode assembly, a cylindrical can having a circular upper surface portion and a side portion extending from the upper surface portion, the side portion having a beading portion formed adjacent to an end thereof so as to be inwardly recessed and a crimping portion formed by bending an end of the side portion, the can receiving the electrode assembly, and a cap plate coupled to an open end of the can, the cap plate having a notch formed therein, wherein the rupture pressure of the notch is lower than the uncrimping pressure of the crimping portion. The cylindrical secondary battery may be efficiently designed by designing and controlling factors that affect the rupture pressure and uncrimping, and safety of the cylindrical secondary battery can be improved by performing control such that uncrimping does not occur before rupture of the notch.