Time-Domain Modeling of Constant Phase Elements for Simulation of Lithium Battery Behavior

A computational model for simulating the time-domain response of lithium batteries under arbitrary charging and discharging profiles is presented. The methodology is based on first formulating a mathematical model that describes the time-domain voltage-current characteristics of constant phase elements (CPEs), and then uses multiple series-connected CPEs, as well as charge transfer resistances, output resistances, and inductances, to form the computational model. The criteria for ensuring the stability of the computational model will be derived. The validity of the computational model is confirmed by comparing the simulation results of a model consisting of three series-connected CPEs with the measurement results of six SANYO 18650, 3300-mAh, 3.7-V rechargeable Li-ion batteries under controlled charging and discharging profiles. Finally, the accuracy of the computational model will be compared to the accuracy of the models using different orders of parallel resistor-capacitor networks.