Mathematical model for a spirally-wound lithium-ion cell

A new computational method is proposed that can be used to reduce the numerical difficulties in modeling the electrical and thermal behavior of a spirally wound Li-ion cell. By analyzing the winding locus of the electrodes, some important geometric relationships of the spiral surfaces are identified, and algorithms for coordinate transform and variable extrusion between 2-D and 3-D domains are derived. Our method reduces the computation time and memory requirements needed to simulate the cell performance. The accuracy of our method was validated by model-to-model comparisons.