Physics-Based Circuit Simulation Model of Lithium-Ion Batteries for Model-Based Design of Electrochemical Energy Storage Systems

Electrochemical energy storage systems function through the cooperative operation of batteries, power converters, and other components. Therefore, methodologies that coordinate electrochemical knowledge with power-system engineering are required to advance the system design and control of such systems. In this paper, a novel physics-based circuit simulation model of a lithium-ion battery is developed as a multi-domain analysis tool. In this model, ion conduction resistance, charge transfer resistance, and open-circuit potential are time-varying elements obtained by coupling a mathematical model to a transmission-line model of a porous electrode to enhance the physical principles in the equivalent circuit model. The model is implemented in a circuit simulator, and the actual measured constant-current charge/discharge curves at rates up to 10C are calculated with high accuracy. We use the circuit simulator to analyze the energy storage system model with a battery pack expanded from this model, a two-quadrant chopper, and a smoothing circuit. On the basis of electrochemical theory, we clarify the effect of the switching operation of the power converter in the system side on the current distribution inside the porous electrode.