The Effects of Varying Charging Rates on Optimal Charging Station Choices for Electric Vehicles

As the demand of plug-in electric vehicles (EVs) grows rapidly, the corresponding charging infrastructures are expanding. These charging stations are located at various places and with different congestion levels. An important choice faced by an EV driver is to decide which charging station to go in order to reduce the overall charging time. Due to the physical characteristics of an EV battery, charging rate is typically reduced as the battery charges. This feature is often overlooked in the existing literature. In this paper, we study the charging station choice problem for EV drivers in a stylized model with two charging stations with explicit modeling of charging rate variations over time. Specifically, we study how different locations and remaining battery capacities of EVs affect their choices of charging stations under various charging rate functions. We analytically characterize the equilibrium strategies and find that co-located EVs may make different decisions depending on the charging function and/or remaining battery levels. Furthermore, we investigate numerically the impact of modeling parameters on the charging decisions.