Detailed Modelling Procedure for Lithium-ion Battery Using Thevenin Equivalent

This paper presents a comprehensive procedure for modelling of Lithium-ion batteries. The proposed modelling procedure adopts Thevenin equivalent circuit of both first and second orders in order to incorporate the dynamic characteristics of Li-ion batteries. The model parameter extraction process is done through the use of pulse discharge (PD) and pulse charge (PC) tests and the procedure is discussed in detail. The effect of self-discharging is ignored due to its very large time constant. In order to verify the accuracy of the model, comparison of simulation results with experimental data is demonstrated for three temperatures, 0°C, 25°C and 45°C. The modelling technique for the battery would specially find applications in electric vehicle based simulations where the load current is highly pulsating and the battery gets very frequently charged and discharged.