Study on the Thermal Performance of Lithium-Ion Batteries Based on an Electrochemical-Thermal-Magnetic Multiphysics Coupling Model

Abstract

The widespread application of lithium-ion batteries in electric vehicles and high-power scenarios has spurred advances in fast-charging and thermal management technologies. However, the coupled regulatory mechanism of external or self-generated magnetic fields on internal thermal performance and electrochemical characteristics during operation remains unclear. In this study, a three-dimensional electrochemical–thermal–magnetic fully coupled finite element model is established for a pouch-type lithium-ion battery based on the Doyle–Fuller–Newman pseudo-two-dimensional (P2D) baseline framework. By incorporating magnetohydrodynamic (MHD) effects and Hall-effect corrections, the model quantitatively characterizes how Lorentz forces modulate ion-transport kinetics at the electrolyte and electrode interfaces. Crucially, a closed-loop bidirectional coupling feedback mechanism is established between the microscopic electrochemical/magnetic transport kinetics and the macro-scale three-dimensional energy conservation equation, where spatial temperature variations dynamically adjust temperature-dependent transport properties. Results indicate that the external magnetic field effectively suppresses concentration polarization by altering charged ion trajectories, thereby reconstructing the local current-density field and Joule heat generation rate. Under 1C discharge conditions, applied magnetic fields of 0.2 T and 1.0 T suppress the temperature rise at the end of discharge by 19.0% and 35.7%, respectively, while markedly enhancing thermal uniformity across the cell. This study provides a theoretical baseline for magnetically assisted battery thermal management and high-safety charging protocol design.