Recently there has increased the interest in electric vehicle routing problems (eVRP). These problems extend classical VRP to account for the technical features of electric vehicles. Two of these features are the short driving range and the relatively long battery charging time. Because of the short driving range, eVRP solutions frequently include routes with planned detours to charging stations (CSs) where the vehicles recharge. The researchers in eVRPs use one (or both) of the following assumptions: (i) the vehicles fully charge their batteries every time they reach a CS, and (ii) the battery charge level is a linear function of the charging time. In practical situations, however, the amount of charge is a decision variable, and the battery charge level is a concave function of the charging time. The goal of this study is to evaluate the impact of different charging assumptions commonly used in the literature with respect to the partial charging policy and the nonlinear charging function, in terms of the quality and feasibility of eVRP solutions. Our results suggest that neglecting partial and nonlinear charging may lead to infeasible or overly expensive solutions.
Mots clés : Vehicle routing problem, Electric vehicles, Charging assumptions