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With the increase of environmental awareness, logistics companies begin to use different types of electric vehicles for deliveries. The types of vehicles differ with respect to battery capacity, battery charge rate, battery consumption rate, load capacity, fixed cost and variable cost. In this paper, we present the heterogeneous electric vehicle routing problem with time windows. The problem is formulated as a mixed integer programming model. A modified branch-and-price algorithm is proposed to obtain the optimal solution. In order to accelerate converging process, we generate the lower bound and upper bound of the solution to pre-process the vehicle types and compress the solution space. Furthermore, compared with the MIP solver of CPLEX, the computational results based on the benchmark instances show the accuracy and efficiency of the algorithm. Finally, the effect of variable cost is analyzed based on different sized examples. [ABSTRACT FROM AUTHOR]