Energy consumption optimization for the electric vehicle routing problem with state-of-charge-dependent discharging rates

The demand for electric vehicles has significantly increased owing to problems related to global energy and the environment. Therefore, electric vehicle routing problems have recently gained considerable attention. Previous studies on electric vehicle routing problems have assumed constant battery charging and discharging rates. However, in reality, the charging and discharging rates are affected by the state of charge. This study investigates an electric vehicle routing problem considering nonlinear charging and discharging functions, wherein the charging and discharging rates depend upon the state of charge. The effect of the state-of-charge-dependent characteristics was investigated, and a nonlinear discharging function was developed. Additionally, a mixed-integer linear programming model was developed, and an efficient algorithm was proposed. The experimental results demonstrated that neglecting the effect of the state of charge might result in infeasible or inferior solu-tions. Furthermore, the results also demonstrated the change in optimal charging behavior depending upon the type of charging stations and the order of visits.