EV Charging Station Technology and Infrastructure

What is the difference between regular charging and fast charging stations?

Regular charging stations are primarily installed in residential or urban environments, such as outside people’s homes or in public car parks. These are based on alternating current (AC) and tend to have fairly low voltages. They take several hours to charge a vehicle, but this is not usually a problem when people are at home, at work or out shopping, for example. But to remove range anxiety and enable drivers to recharge quickly during longer journeys, faster electric vehicle charging stations are increasingly being installed along major travel corridors such as motorways. These fast chargers are based on direct current (DC) and have higher voltages. This technology is already being taken a step further, leading to the emergence of high-power DC (HPDC) which can provide up to 350 kW of power for ultrafast EV charging. HPDC connectors are actively cooled with cooling liquid to facilitate this. CharIN is supporting the further development and adoption of DC and HPDC.

What are the most important aspects to consider when testing EV charging stations?

Electrical safety is of course critical to protect users of EV charging equipment. In the EU the IEC/EN 61851 series of standards is the main protocol used. Its general requirements apply to all EV charging stations. However, different parts of the standard apply depending on whether it is an AC or a DC charging station. The emerging HPDC technology means that users will be exposed to even higher voltages, which makes it increasingly important that the standards adequately address all the risks. There are still some gaps in the IEC/EN 61851. These can currently be filled by including additional standards such as IEC 61439 (low-voltage switchgear and controlgear assemblies) and IEC/EN 62368-1 (safety of communication technology equipment) in the testing and certification process of electric vehicle charging systems, for example.

Electromagnetic compatibility (EMC) testing ensures that the electronics within EVSE do not emit interference, and that they will continue to function in the presence of various electromagnetic phenomena such as power supply surges or radiated electric fields. DEKRA also applies additional environmental protection standards to be sure that the high-voltage equipment inside a charging station is protected from the elements such as rain, ice, dust and sand.

Conformity testing ensures that the all elements of the EVSE – the vehicle, the charging station and the back office – can communicate with one another. This is essential so that the right amount of electricity is provided to the right vehicle, and the user is billed at the right price. The ISO/IEC 15118 standard governs electronic communications in EVSE. Another relevant test in this area is Open Charge Point Protocol (OCPP) testing, developed by the Open Charge Alliance. The OCPP protocol is used worldwide to correctly exchange information between the EV charging station and the charging station management system operated by the CPOs. The advancement of vehicle-to-grid (V2G) and smart charging applications is making communication protocols even more crucial, as the EV is increasingly becoming an active element in the grid.