Optimal Battery and PV Sizing of Charging Stations Considering Battery Dynamic Characteristics

To reduce the carbon emissions from vehicles and realize carbon neutrality, it is necessary to promote the application of battery energy storage system (BESS) and photovoltaic (PV) in electric vehicle charging stations. Meanwhile, the implementation of BESS and PV in charging stations can be a solution to help to reduce the progressively increase of the charging load in energy distribution networks. Finding the optimal size of BESS and PV is necessary for charging stations to save long-term costs. In our paper, a novel refined BESS model considering BESS dynamic characteristic is established, which takes BESS operation characteristics of dynamic capacity, dynamic lifetime and dynamic efficiency into account. Based on the established BESS model, a bi-level optimization method is proposed to find out the optimal BESS and PV capacity, and the optimal solution is found by using a genetic algorithm (GA) with elitist strategy. Then a case study of a charging station in Shanghai proves the effectiveness of the proposed method. The simulation results confirm that: 1) the BESS and PV size can be determined for optimal benefits by the proposed model; 2) the proposed refined BESS model, which considers BESS dynamic characteristics, is feasible; 3) the proposed operation strategy in typical days, could improve the benefits and the energy consumption of the PV systems for the operator of the charging stations.