Oval Wound Electrode Assembly With Layer Spacing for Stress Relief
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Solution Overview
Problem
During the molding of a wound body of sheets by pressing, the curved portions of the sheets are deformed, resulting in a large stress applied to these areas, which can lead to unsatisfactory winding and potential issues in power storage devices.
Innovation Solution
A method for producing a wound electrode assembly involves 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 spaces between inner and outer layers, which alleviates stress during pressing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the lamination sheet is wound tightly around the winding shaft with standard feeding length, then the winding density is improved, but the stress applied to curved portions during pressing increases
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.
Solution Approach 2:
The patent applies beforehand cushioning by intentionally creating spaces between layers during the winding process. These spaces act as cushions that absorb stress during the subsequent pressing operation, preventing excessive stress concentration on curved portions of the lamination sheet.
2Device complexity
If the lamination sheet is fed at standard length per rotation, then the manufacturing process is simple, but spaces between layers are insufficient during pressing
Solution Approach 1:
The patent modifies the feeding length parameter to be longer than the outer circumferential length of the winding shaft per rotation. This simple parameter change ensures adequate spaces between layers during pressing without requiring complex feeding control mechanisms or additional device components.
Data Source
AI summary
A method for producing a wound electrode assembly includes a winding a lamination sheet around a winding shaft by feeding the lamination sheet and by rotating the winding shaft, the winding shaft having an outer circumferential surface of an oval shape including a pair of flat surfaces facing each other and a pair of arcked surfaces connecting both of ends of the pair of flat surfaces to each other; and pressing the lamination sheet formed to have an oval shape, such that a pair of flat portions of the lamination sheet are pressed to each other. In the winding the lamination sheet, the lamination sheet is fed by, per rotation of the winding shaft, a length longer than an outer circumferential length corresponding to the number of winds of the lamination sheet wound around the winding shaft.