Unplugged

It couldn't be more convenient: If you maneuver your electric car correctly onto the designated parking space, the charging process starts automatically. A base plate in the parking lot transmits energy via a magnetic field to a receiver plate on the vehicle's underside and then to the battery. The technology for inductive charging of electric cars already exists and is being developed by the US company WiTricitiy, for example, which also has a subsidiary in Switzerland. What is missing is the regulatory framework – and practical experience of the advantages and disadvantages of inductive charging compared to wired, conductive charging. This is precisely where the INLADE project comes in: "We want to find out how inductive charging proves itself in everyday life and what regulatory changes will be necessary for the concept to become established," explains Mathias Huber from Empa's Chemical Energy Carriers and Vehicle Systems laboratory.

While the permissions for the charging stations are still pending, the first vehicle equipped with a charging plate has already received road approval. This required extensive electromagnetic compatibility (EMC) measurements and electrical safety tests. "The aim was to ensure that the magnetic field during inductive charging does not have any negative effects on other devices inside and outside the vehicle and, of course, on people," explains Huber. Together with representatives of project partner Eniwa AG, who operate this first vehicle, the Empa researcher accompanied the tests in the laboratory of the EMC Test Center in Regensdorf. Empa will soon be putting its own prototype vehicle and a corresponding charging station into operation. The aim is to be able to assess and evaluate the energy efficiency and reliability of the new system. "We are investigating the efficiency of both charging systems in different environmental conditions such as rain or snow," says Huber. According to the manufacturer, the efficiency of inductive charging should be around 91 percent. Huber: "These values are comparable with wired charging."