Rechargeable Battery Case Shape for More Electrolyte Volume
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Solution Overview
Problem
Cylindrical rechargeable batteries face challenges in accommodating enough electrolyte solution due to excess space generated by their circular structure and internal case structure, which limits the battery's capacity and efficiency.
Innovation Solution
The rechargeable battery design incorporates a case with flat sides and curved ends that accommodate a unique electrode assembly with first and second wound parts connected by a connection part, allowing for an increased electrolyte solution accommodating space between the wound parts and the flat sides of the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a cylindrical case structure is used for the rechargeable battery, then the battery has a compact and simple external form, but excess space is generated between the electrode assembly and the case wall, reducing the electrolyte solution accommodation volume
Solution Approach 1:
The patent applies asymmetry by transitioning from a traditional cylindrical case to a prismatic case with flat sides and curved ends. This asymmetric shape better conforms to the rectangular cross-section of the wound electrode assembly, eliminating excess space and maximizing electrolyte solution accommodation volume while maintaining a compact form factor.
Solution Approach 2:
The patent retains curvature elements by designing the prismatic case with curved ends rather than completely sharp edges. This partial curvature maintains some ergonomic and structural benefits of cylindrical designs while allowing flat sides to maximize space utilization for the electrolyte solution.
2Volume of moving object
If the electrode assembly is tightly wound to reduce volume, then the case volume is reduced, but the space for electrolyte solution accommodation is also reduced
Solution Approach 1:
The prismatic case design with flat sides creates an asymmetric geometry that matches the rectangular profile of the wound electrode assembly. This eliminates the radial gaps present in cylindrical designs, allowing the electrode assembly to be tightly wound while maximizing the remaining space for electrolyte solution accommodation.
3Quantity of substance
If flat sides are introduced in the case structure, then the electrolyte solution accommodating space is increased, but the manufacturing complexity of the case increases
Solution Approach 1:
The patent introduces curvature only at the ends of the prismatic case, rather than making the entire case complex. This limited use of curved surfaces maintains manufacturing simplicity for the majority of the case structure while achieving the space optimization benefits of flat sides, balancing manufacturability with electrolyte solution accommodation.
Data Source
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AI summary
A rechargeable battery includes an electrode assembly including a first wound part and a second wound part connected by a connection part, the electrode assembly being formed by being wound at each of both ends of a stacked body of a first electrode plate, a first separator, a second electrode plate, and a second separator; and a case that accommodates the electrode assembly, wherein the case includes flat sides facing each other at both sides of the case in a width direction, and curved sides at both ends of the case in a length direction, and the flat sides and the first wound part and the second wound part surround an electrolyte solution accommodating space therebetween.