Multi-type fast charging stations are being deployed over Europe as electric vehicle adoption becomes more popular. The growth of an electrical charging infrastructure in different countries poses different challenges related to its installation. One of these challenges is related to weather conditions that are extremely heterogeneous due to different latitudes, in which fast charging stations are located and whose impact on the charging performance is often neglected or unknown. The present study focused on the evaluation of the electric vehicle (EV) charging process with fast charging devices (up to 50 kW) at ambient (25 °C) and at extreme temperatures (−25 °C, −15 °C, +40 °C). A sample of seven fast chargers and two electric vehicles (CCS (combined charging system) and CHAdeMO (CHArge de Move)) available on the commercial market was considered in the study. Three phase voltages and currents at the wall socket, where the charger was connected, as well as voltage and current at the plug connection between the charger and vehicle have been recorded. According to SAE (Society of Automotive Engineers) J2894/1, the power conversion efficiency during the charging process has been calculated as the ratio between the instantaneous DC power delivered to the vehicle and the instantaneous AC power supplied from the grid in order to test the performance of the charger. The inverse of the efficiency of the charging process, i.e., a kind of energy return ratio (ERR), has been calculated as the ratio between the AC energy supplied by the grid to the electric vehicle supply equipment (EVSE) and the energy delivered to the vehicle’s battery. The evaluation has shown a varied scenario, confirming the efficiency values declared by the manufacturers at ambient temperature and reporting lower energy efficiencies at extreme temperatures, due to lower requested and, thus, delivered power levels. The lowest and highest power conversion efficiencies of 39% and 93% were observed at −25 °C and ambient temperature (+25 °C), respectively.
Exposing electric vehicles (EV) to extreme temperatures limits its performance and charging. For the foreseen adoption of EVs, it is not only important to study the technology behind it, but also the environment it will be inserted into. In Europe, temperatures ranging from −30 °C to +40 °C are frequently observed and the impacts on batteries are well-known. However, the impact on the grid due to the performance of fast-chargers, under such conditions, also requires analysis, as it impacts both on the infrastructure’s dimensioning and design. In this study, six different fast-chargers were analysed while charging a full battery EV, under four temperature levels (−25 °C, −15 °C, +20 °C, and +40 °C). The current total harmonic distortion, power factor, standby power, and unbalance were registered. Results show that the current total harmonic distortion (THDI) tended to increase at lower temperatures. The standby consumption showed no trend, with results ranging from 210 VA to 1650 VA. Three out of six chargers lost interoperability at −25 °C. Such non-linear loads, present high harmonic distortion, and, hence, low power factor. The temperature at which the vehicle’s battery charges is crucial to the current it withdraws, thereby, influencing the charger’s performance.
The new generation of fast charging systems faces a formidable technological challenge, aiming to drastically reduce the time needed to recharge an electric vehicle as a way to tackle the range anxiety issue. To achieve this, high power (up to 350 kW) is transferred from the grid to the vehicle, leading to potentially high values of low frequency magnetic fields. This study presents the results of measurements of magnetic flux density (B-field) emitted by two different high power charging systems. The electric vehicle used for the recharge was able to digest up to 83 kW of delivered power. The test procedure was designed to identify the locations where the maximum B-field levels were recorded and to measure the exposure indices according to reference levels for general public exposure defined in the Council Recommendation 1999/519/EC. Measurements in close proximity to the power cabinets during the recharge revealed that, at some points, exposure indices were higher than 100%, leading to the identification of a distance from the system components at which the value was lower than the reference level. In the worst case, this distance was 31 cm.
Assessing the potential of electric vehicles against actual user needs is a key-issue to integrate individual e-mobility in sustainable transport. An extensive analysis of real-life mobility has been carried out, in view of deriving and quantifying the potential of introducing electric vehicles in urban environment. A large activity data set collected with GPS black boxes mounted on approximately 16,000 vehicles monitored for a one-month period in the Italian province and city of Modena has been purchased and post-processed in order to characterise vehicles’ driving patterns. The ability of different types of electric vehicles to cover the real mobility needs of the users has been then investigated, estimating the percentage of individual trips which might be suitable to be performed by electric vehicles, as well as their potential impact on the electric energy distribution grid depending on different recharging behavioural models. The results show that more than 80% of these trips might be driven electric and that a fleet share lying between 10% and 25% can be immediately converted to battery electric vehicles, being not affected by their limited range. The quantitative key-insights based on real-life mobility data enable to address several issues, ranging from technological aspects, policy impacts and interoperability possibilities offered by the integration of electromobility with the energy distribution grid