Secondary Battery Can with Localized Thickness Variation
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Solution Overview
Problem
Secondary batteries face deformation and safety risks during drop or collision tests due to uneven stress distribution, particularly at the top and bottom ends of the can, which are prone to deformation and potential explosion or fire.
Innovation Solution
The battery design features a can with thicker top and bottom ends compared to the middle portion, formed by welding metal boards of different thicknesses and folding them to create a unitary metal board, which is then welded to minimize deformation and enhance heat radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the can is made with uniform thickness, then the manufacturing process is simple, but the top and bottom ends are prone to deformation during drop or collision tests
Solution Approach 1:
The can is designed with non-uniform wall thickness, where the top and bottom ends have greater thickness than the middle portion. This local quality variation provides enhanced strength and deformation resistance at the impact-prone top and bottom ends, while maintaining lighter weight and adequate protection in the middle section.
2Strength
If the can wall thickness is increased, then the strength and deformation resistance are improved, but the heat radiation efficiency is reduced
Solution Approach 1:
The can employs localized thickness variation, being thicker at top and bottom ends for impact resistance while maintaining thinner walls in the middle section to preserve heat radiation efficiency. This selective thickening ensures structural strength is enhanced only where mechanically necessary, without compromising thermal performance across the entire can surface.
3Temperature
If the can has thicker top and bottom ends, then the heat radiation efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The can is fabricated by segmenting the wall thickness into different zones: thicker top and bottom ends and a thinner middle portion. This segmentation is achieved through a multi-step welding process that joins metal boards of varying thicknesses, allowing the can to optimize both thermal radiation performance and structural strength while managing manufacturing complexity through systematic assembly.
4Reliability
If the can structure is reinforced at top and bottom ends, then the safety during impact tests is improved, but the weight of the battery increases
Solution Approach 1:
The can implements localized reinforcement by increasing wall thickness only at the top and bottom ends where impact forces are concentrated during drop tests. The middle portion maintains thinner walls, avoiding unnecessary weight addition in regions that experience less mechanical stress, thereby optimizing the weight-strength ratio for improved safety without excessive weight penalty.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces deformation during impact tests and improves heat radiation efficiency by distributing stress more evenly across the can's regions, thereby enhancing the battery's safety and performance.
Implementation Method 1
The can includes metal boards having different thicknesses, and the metal boards are welded together to form a unitary metal board
Implementation Method 2
The unitary metal board are folded, and end portions of the unitary metal board are welded together
Implementation Method 3
end portions of the unitary metal board are welded together
Implementation Method 4
the first electrode tab may be welded to a bottom surface of the can
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A secondary battery (100) includes an electrode assembly (110) including a first electrode plate (111), a second electrode plate (112), and a separator (113) between the first electrode plate (111) and the second electrode plate (112), a can (120) accommodating the electrode assembly, (110) and a cap assembly (130)coupled to and sealing the can (120), wherein a top end and a bottom end of the can (120) each have a thickness (T1, T2) that is greater than a thickness (T3) of a middle portion of the can (120).