Coupled electro-thermal modeling of lithium-ion batteries for electric vehicle application

The lithium-ion battery is a complex system that is both non-linear and non-stationary, which involves electrical, thermal and electrochemical dynamics In order to deepen the understanding of battery system dynamics, in this paper, an electro-thermal coupled model is proposed for a 40 Ah lithium-ion battery cell with Nickel Manganese Cobalt Oxide cathode material and graphitic anode. The developed model takes into account the dynamics of the high power applications and then allows to accurately present the physicochemical phenomena occurring in a battery cell. It is built through a dynamic equivalent circuit and a thermal model. The battery is divided into n×m nodes with two dimensions and each node is represented by an equivalent circuit. Both models are coupled in the same loop, the electric-thermal through the distribution of power losses to calculate the distribution of temperature and the thermal-electric through the mean temperature of the battery to update the electric parameters. The obtained results show that the proposed model is able to simulate the dynamic interaction between the electric and the thermal battery behavior, and high performance for the cell surface temperature prediction.