Curved Spiral-Wound Electrode Assembly for Flexible Battery Cells
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Solution Overview
Problem
Conventional electrode assemblies lack flexibility to be easily integrated into devices with curved or varied shapes, such as smartphones and flexible displays, while maintaining battery characteristics.
Innovation Solution
A one-directionally spiral-wound electrode assembly with a separator sheet between positive and negative electrode sheets, where both side end portions are bent in the same direction, forming a naturally curved shape with a curvature radius determined by the ratio of horizontal to vertical length, allowing for increased flexibility and maintaining battery characteristics even with repeated bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electrode assembly is made with conventional rigid structure, then the battery characteristics are maintained, but the flexibility and adaptability to curved device shapes are insufficient
Solution Approach 1:
The electrode assembly is designed with a curved configuration where both side end portions are bent in the same direction with a curvature radius R satisfying R ≥ S×t where S≥8 and t is the average thickness. This curvature design enables the electrode assembly to adapt to curved device shapes while maintaining structural integrity and battery performance through repeated bending.
Solution Approach 2:
The invention changes the geometric parameters of the electrode assembly by establishing specific relationships between curvature radius R, average thickness t, horizontal length x, and vertical length y (where x/y ≥ 1). These parameter changes transform the rigid conventional structure into a flexible curved structure that maintains reliability.
2Adaptability or versatility
If the electrode assembly is bent to fit curved device shapes, then the flexibility is improved, but the electrode may break and battery characteristics deteriorate
Solution Approach 1:
By designing the electrode assembly with a predetermined curvature radius R satisfying R ≥ S×t (S≥8), the structure is optimized to distribute bending stresses evenly, preventing electrode breakage while achieving the required flexibility for curved device integration.
Solution Approach 2:
The electrode assembly is pre-configured with a curved shape matching the target device geometry, so that when installed, it experiences minimal additional bending stress. This preliminary configuration prevents breakage by avoiding sharp bends during installation and operation.
3Adaptability or versatility
If the electrode assembly has longer horizontal length than vertical length, then the curved shape and flexibility are improved, but the space occupation may increase
Solution Approach 1:
The curved configuration with x/y ≥ 1 allows the electrode assembly to fit into curved device spaces more efficiently than a rectangular arrangement, potentially reducing the overall space occupation by conforming to the device's curved geometry rather than requiring additional flat space.
Data Source
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AI summary
The present invention provides an electrode assembly having a one directionally spiral-wound structure with a separator sheet interposed between a positive electrode sheet and a negative electrode sheet, wherein the electrode assembly has a horizontal length (x) equal to or more than three times a vertical length (y), and both side end portions of the electrode assembly are bent together in the same direction by a curvature radius (R) satisfying the following Equation 1: S 1/lnx/y*t=R wherein t is an average thickness (mm) of the spiral-wound electrode assembly, x is the horizontal length of the electrode assembly, and y is the vertical length of the electrode assembly, and S is a constant of 8 or more, and ln(x/y) ≥ 1.