Oval Wound Electrode Assembly With Reduced Curved-Sheet Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During the production of wound electrode assemblies, the curved portions of the sheets are subjected to high stress when molded, which can lead to inadequate winding and potential defects in the power storage device.
Innovation Solution
A method involving winding a lamination sheet with a band-like positive electrode sheet, a negative electrode sheet, and separator sheets around a winding shaft with an oval outer surface. The lamination sheet is fed at a length longer than the outer circumferential length per rotation, creating a space between inner and outer layers, which alleviates stress on the curved portions during pressing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lamination sheet is wound tightly around the winding shaft with standard feeding length, then the winding density is improved, but the stress on curved portions during pressing increases significantly
Solution Approach 1:
The patent changes the feeding parameter by feeding the lamination sheet at a length longer than the outer circumferential length of the winding shaft per rotation. This parameter change creates spaces between inner and outer layers, which reduces stress on curved portions during pressing while maintaining adequate winding density.
2Stress or pressure
If the lamination sheet is fed by a length longer than the outer circumferential length per rotation, then the stress on curved portions is reduced, but the winding density decreases
Solution Approach 1:
The patent optimizes the feeding length parameter to be longer than the outer circumferential length but controls the extent of elongation to maintain adequate winding density. This balanced parameter change reduces stress on curved portions while preserving sufficient winding density for product performance.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for producing a wound electrode assembly (1) includes a winding a lamination sheet (2) around a winding shaft (21) by feeding the lamination sheet (2) and by rotating the winding shaft (21), the winding shaft (21) having an outer circumferential surface of an oval shape including a pair of flat surfaces (21a) facing each other and a pair of arcked surfaces (21b) connecting both of ends of the pair of flat surfaces (21a) to each other ; and pressing the lamination sheet (2) formed to have an oval shape, such that a pair of flat portions (2a) of the lamination sheet (2) are pressed to each other. In the winding the lamination sheet (2), the lamination sheet (2) is fed by, per rotation of the winding shaft (21), a length longer than an outer circumferential length corresponding to the number of winds of the lamination sheet (2) wound around the winding shaft (21).