Economic evaluation of a PV combined energy storage charging station based on cost estimation of second-use batteries

Recycling of a large number of retired electric vehicle batteries has caused a certain impact on the environmental problems in China. In term of the necessity of the re-use of retired electric vehicle battery and the capacity allocation of photovoltaic (PV) combined energy storage stations, this paper presents a method of economic estimation for a PV charging station based on the utilization of retired electric vehicle batteries. According to the second-use battery technology, a capacity allocation model of a PV combined energy storage charging station based on the cost estimation is established, taking the maximum net income of the PV combined energy storage charging station as the objective function, the real-time power balance of the PV combined energy storage charging station and the state of charge (SOC) of the energy storage system as constraint conditions. As the economy of the second-use battery energy storage system is related to the purchase, operation and maintenance costs of the energy storage system, the capacity cost of the retired electric vehicle batteries is estimated by the double declining balance method. In order to facilitate comparative analysis, the optimal capacity configuration of the PV combined energy storage charging station is given by the teaching-learning-based optimization (TLBO) and particle swarm optimization (PSO) algorithms respectively. The net present value (NPV) is adopted to evaluate the cost and benefit of the PV charging station with the second-use battery energy storage during the lifecycle. Combined with the actual operation data of the PV combined energy storage charging station in Beijing, the economy of the PV combined energy storage charging station is evaluated according to the conventional batteries and the second-use batteries. The simulation results show that the optimal capacity configuration obtained by the TLBO algorithm is better than that of the conventional batteries obtained by the PSO algorithm, which provides a theory basic for the re-use of the retired electric vehicle batteries and has a certain practical value of the project.