Modified Pseudo-Two-Dimensional Model for Spiral-Wound Cylindrical Lithium-Ion Batteries

Accurate prediction of cell voltage and temperature of lithium-ion batteries (LIBs) is crucial for both design and operation of LIB modules/packs. The pseudo-two-dimensional (P2D) model is widely used to capture the electrochemical behavior of LIBs owing to its computational efficiency. For capturing thermal behavior, P2D model is generally coupled with a lumped thermal model. This study investigates the sufficiency of P2D-lumped model for cylindrical LIBs for tabbed and tab-less design: first, via a scale analysis and then, by comparing its predictions with detailed electrochemical-thermal (ECT) models: full axi-symmetric model for continuous tab (tab-less) and full spiral model for single tabbed design. While the predictions of P2D-lumped model align well with full model for tab-less design, discrepancies arise for tabbed design due to unaccounted potential losses and ohmic heat generation in the azimuthal direction. These discrepancies are found to intensify with cell form factor and discharge rate. The scale estimates (secured via scale analysis) for potential losses and ohmic heat generation exhibit congruence with the observed disparities, which allows to propose a corrected P2D-lumped model. The utility of the study is not limited to a corrected model only, but also to understand the challenges with larger form factors and tab design.