| The development of electric vehicle (EV) is an important way to relieve environmental pressure and ensure energy safety. The construction of electric energy refueling facilities is an indispensible condition for EVs’promotion. Among the various electric energy refueling facilities, EV battery swap stations have short swapping time, flexible recharging time, convenient battery maintenance and do not need to equip with large parking lots. Proper configuration of EV batteries and chargers in the swap stations is the basic problem in the planning and design of swapping stationsConsidering the service availability of the EV battery swap station and demand response, this paper proposed a method of the optimization of capacity configuration for the station. Firstly, combined with the structure and operation process of the battery swap station, the charging strategy introduced demand response to real time price of electric energy is proposed based on the common "charge directe after swap" operation mode. From the above two different operation strategy, a time sequential simulation model of the station’s operation states is established. Input the number of EVs that need to swap batteries and the initial SOC (State of Charge), the number of EVs and EV batteries in different states can be obtained by the simulation. Then, the service availability of the system of the battery swap station is studied in this paper. In order to make quantitative evaluation of service availability for the battery swap station, the evaluation indices are put forward from the aspects of available swapping times, the available service time of the system, and waiting time for swapping synthetically. Combined with the time sequential simulation model, calculation method of the evaluation indices for the swap station is proposed. Based on the above-mentioned researches, the mathematical model of optimization of capacity configuration is built, with minimum annual cost of parchasing EV batteries and chargers and their maintenance expense being the objective function. The constraints of service availability is considered in the model. The solving procedure of the mathematical model is provided based on differential evolution algorithm. Finally, a specific case is studied. Firstly, the impacts of different distubution of the time when EVs need to swap their batteries and different constraints of service availability are compared. Then, the optimal configuration schemes under the situation of the charging strategy introduced different demand response plan is studied and their effects on configuration and charging cost are compared. At last, the operation of the swap station with different configuration under different situation is analysed. |
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