It will soon be possible to charge electric cars on either direct current (DC) or alternating current (AC) thanks to a new rapid charging system being developed by BMW and Siemens.
The system was tested successfully in September with a Siemens charging station and a BMW ActiveE vehicle, and now the companies have submitted proposals for standardising DC charging to the International Electrotechnical Commission.
In short, the system uses plugs that have been standardised for AC charging and then modified to accommodate DC rapid charging too – whereas previously they needed to use two different sockets.
It is hoped that the system will help address some of the key aspects that influence consumer acceptance of electric cars – including charging times and vehicle range. At the moment, batteries for electric cars have to be recharged more often than a conventional vehicle needs to be refuelled and the recharging process can take several hours. However, with DC technology, charging times can be achieved in half an hour or less.
Compared to AC systems, the DC technology is located outside the vehicle at the charging station – this means that the cars that use it can be made lighter. In turn, this increases vehicle range and makes electric vehicles more attractive to fleet operators. Special charging units are needed, however, hence the push for a flexible solution.
Now the AC and DC plugs fit into the same socket with communication between the vehicle and charging station also standardised. This means it will be able to support additional functions, including smart charging, in the future.
