Compared to cylindrical cells, prismatic cells are more prone to deformation during the winding process. Prismatic wound cells are typically wound with multiple or full tabs. What causes deformation in prismatic wound cells?
External factors:
1. Winding tension varies cyclically with the impact of the winding's rotation;
2. Improper winding control, resulting in increasingly tighter winding, resulting in looseness on the inside and tightness on the outside;
3. Whether the cell is cold-pressed or hot-pressed, and whether the hot-pressing parameters are appropriate;
Internal factors:
1. Electrode expansion after being immersed in electrolyte;
2. Inconsistent shrinkage between the separator and electrode;
3. Lithium ion migration causes expansion and contraction of the electrode;
Deformation caused by external factors can generally be identified during inspection and can be reduced through equipment tuning.
Internal factors, on the other hand, are related to cell design, material selection (separator, electrolyte), injection volume, injection method, formation conditions, and charge/discharge rates. Moreover, this type of deformation requires disassembly and analysis after battery testing, and some may require long-cycle testing to be reflected.
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