Electrochemical Modeling of Fast Charging in Batteries

The acceleration of fast charging capabilities has emerged as a pivotal objective within the realms of the battery, electric vehicle, and energy storage sectors. However, the classical electrochemical models are not able to describe voltages of the cell (U_cell), anode (U_a), and cathode (U_c) at high C-rates. Herein, U_cell, U_a, and U_c are experimentally obtained under various C-rates (0.1–2C) and identified the charge transfer resistance of the cathode (R_CT,c) as the primary rate-limiting factor. Thus, the anode is established as a multi-scale coupling model with Fick's law and phase separation model applied, to discuss their effect on U_a and Li-ion concentration prediction. 2D reconstruction structures for the cathode is established with R_CT,c effect considered. Finally, the U_a, U_c, and U_cell are successfully predicted at different C-rates. Results propose an accurate and versatile electrochemical model and highlight the importance of considering limiting factors in electrochemical modeling for fast charging.