A practical circuit-based model for Li-ion battery cells in electric vehicle applications

This paper proposes a practical circuit-based model for Li-ion cells, which can be directly connected to a model of a complete electric vehicle (EV) system. The goal of this paper is to provide EV system designers with a tool in simulation programs such as Matlab/Simulink to model the behaviour of Li-ion cells under various operating conditions in EV or other applications. The current direction, state of charge (SoC), temperature and C-rate dependency are represented by empirical equations obtained from measurements on LiFePO₄ cells. Tradeoffs between model complexity and accuracy have been made based on practical considerations in EV applications. Depending on the required accuracy and operating conditions, the EV system designer can choose the influences to be included in the system simulation.