Techno-Economic Assessment of Utilising Second-Life Batteries in Electric Vehicle Charging Stations

The number of electric vehicles is increasing in line with the global carbon reduction targets. More households are installing electric charging points to complement the existing charging infrastructure. The increasing electricity prices affected by the global energy/economic crisis however pushed more households towards coupling their charging points with renewable energy generation and storage systems to manage the supply and demand of energy more effectively. In this study, an electric charging station equipped with Photovoltaic panels and an electric storage system utilising second-life Electric Vehicles (EV) batteries is designed and analysed. Various electricity generation capacities are considered to be installed on the roof of the case study building ranging from 5m2 and 20m2. The second-life batteries are disposed from EVs with an 80% state of health. MATLAB Simulink is used for mathematical modelling of system. The second-order equivalent circuit model (ECM) is employed for predication of second-life battery parameters, and the model is validated by experimental data using 3h cylindrical NMC cells. The NMC cell degradation data consists of both real and forecast data in this study. The proposed system is designed based on the worst-case scenario with minimum solar radiation in January. The Box-Behnken design of experiment method is also employed to design the case scenarios to perform the parametric study. The results have demonstrated that the maximum peak charge and discharge C-rate values of the battery modules equals to 0.2C and 0.16C, respectively. The optimum design of the charging station is achieved when the solar system covered 53.3% share of the energy consumed by the electric charging station. The second-life battery size and PV area equals to 7.45kWh and 5.15m2, respectively. The optimum total cost of the second-life batteries and PVs based on literature costing data (excluding labour and auxiliary devices costs) is estimated to be around £1371 in this study.