2nd ICAI 2022

International Conference on Automotive Industry 2022

Mladá Boleslav, Czech Republic

really suitable for charging stations in family houses or residential garages, i.e. at places where the vehicle can stay for an extended period of time to recharge. It is apparent from the name that the charging station is supplying the car with alternated current in this case. Since battery cells are in their nature based on direct current, it is necessary to rectify the alternated current coming from the charging station. This is what the BEV onboard charger (OBC) is meant for. With the AC charging modes, it is necessary to include the losses in the OBC itself as well as possible losses from reactive energy. The table below summarizes the data measured on Hyundai Kona Electric 2020 (64 kWh) with installed OBC of 10.5 kW (3x16 A / 400 V). The data come from a total of 17 charging cycles, which proved a very good repeatability. The vehicle was charged from a wall-box, always to 100% state of charge, at room temperature. The consumed energy was measured using an external energy meter with an accuracy class of 1%. Measured data were used to evaluate the charging efficiency and the extent to which the BEV is capable to take the available power from the charging station, i.e. level of utilization of this power. Table 6: Alternate current charging (average from all charging cycles) BEV charging efficiency (includes losses in the OBC and the battery) [%] 90.5 Average input power (into OBC) [kW] 10.0 Rated voltage at the charging station inlet [V] 3 x 400 V / 50 Hz Actual phase current supply (into OBC) [A] 14.7 Utilization of available charging power by the vehicle [%] 91.8 Average charging power factor [-] 0.99 Maximum charging completion estimate deviation [min.] -21 and +21 Minimum charging completion estimate deviation [min.] -2 a +3 Source: Research data 5.2 DC charging mode (DC mode) The DC mode has relatively higher purchase costs for the charging infrastructure; however, this factor is made up for by the capability of charging with powers that are many times higher (compared to ACmodes). These chargers are frequently encountered at malls, public parking lots and highways, where it is necessary to maximally reduce the charging time. The power of DC charging depends strongly on the BEV’s current traction battery temperature and its state of charge (SOC); it also changes over the course of the charging. Table below summarizes the data measured when charging Hyundai Kona 2020 (64 kWh). These are data from three consecutive charging cycles, where each of the

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