Cylindrical Electrode Assembly Cutouts for Easier Tab Folding
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Solution Overview
Problem
The cylindrical electrode assembly in rechargeable batteries faces challenges in folding the repeatedly wound electrode uncoated portions due to differences in their radii of curvature, making it difficult to compact and weld them effectively.
Innovation Solution
The solution involves forming inclined cutout portions in the electrode uncoated portions, which allows them to be easily folded and overlapped, facilitating the compaction process and welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrode uncoated portions are continuously wound into a cylindrical shape, then the electrode assembly can be formed, but it becomes difficult to fold the uncoated portions toward the center due to different radii of curvature
Solution Approach 1:
The electrode uncoated portions are segmented by forming cutout portions at regular intervals, dividing the continuous uncoated portion into multiple sections. This segmentation allows each section to be folded independently toward the center, overcoming the difficulty caused by different radii of curvature in continuously wound structures.
Solution Approach 2:
Cutout portions are selectively formed only in the electrode uncoated portions, not in the entire electrode structure. This local modification maintains the integrity of the wound electrode while creating specific folding points only where needed, enabling easy folding without affecting the overall cylindrical structure.
2Manufacturing precision
If electrode uncoated portions with different radii of curvature are folded equally, then symmetry is maintained, but it becomes difficult to achieve proper overlap and welding
Solution Approach 1:
By dividing the uncoated portions into segmented sections via cutout portions, each segment can be precisely positioned and overlapped with adjacent segments. This segmentation enables controlled folding that achieves accurate overlap despite variations in radius of curvature across different parts of the cylindrical electrode.
3Productivity
If the electrode assembly structure is simplified without cutout portions, then manufacturing steps are reduced, but folding and compaction become difficult
Solution Approach 1:
Cutout portions are formed locally and selectively in the electrode uncoated portions, adding minimal structural complexity only where needed for folding. This localized modification maintains overall structural simplicity while enabling easy folding operations, thus preserving manufacturing efficiency.
Solution Approach 2:
The segmentation through cutout portions creates natural folding lines that guide the compaction process. This segmentation simplifies the folding operation by providing predetermined bending points, making the compaction process more efficient despite the additional cutout formation step.
Data Source
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AI summary
An electrode assembly includes: first and second electrodes, each comprising a conductive substrate and having an electrode active portion and a first electrode uncoated portion; and a separator. The first electrode, the separator, and the second electrode are stacked on each other and wound. At least one of the first electrode uncoated portion and the second electrode uncoated portion has a plurality of inclined cutout portions inclined with respect to a length direction of the electrode assembly, and an interval between adjacent ones of the inclined cutout portions at a frontal end of the electrode assembly and an interval between adjacent ones of the inclined cutout portions at a rear end of the electrode assembly are different.