Electric cars: this fast wireless charger is very promising

On the other side of the Atlantic, a team from the  Oak Ridge National Laboratory has perfected its wireless charging system which can now transfer 120 kW of energy with an efficiency of 97%.

Recharge an electric car as quickly as you fill up with fuel today, all  via wireless energy transfer . The promise is exciting but for the moment still improbable. However, it is a little less thanks to the progress that has just been made by researchers from the Oak Ridge National Laboratory (ORNL). They demonstrated a wireless induction charging system that can deliver 120 kW of energy with an efficiency of 97%, which they say is comparable to wired fast chargers.

This is six times the power delivered by the wireless charging system that the ORNL had presented in 2016 and which made 20 kW. In order to increase the performance of their system in this way, the researchers have designed a new type of coil associated with the latest power electronic devices made of silicon carbide. The result is a light and compact coil that does not overheat and minimizes power loss during transfer.

Towards dynamic charging on the motorway

The device uses two coils. It takes energy from the network and converts it into high frequency alternating current which generates a magnetic field and transfers the energy through an air gap of approximately 15 cm. Once the energy is sent to the secondary coil, it is converted back into direct current and stored in the vehicle’s batteries.

The ORNL team does not intend to stop there. It says it continues to push development to increase power transfer to 350-400 kilowatts and achieve an electric vehicle charging time equivalent to or less than 15 minutes. Scientists are also working on dynamic wireless charging that could work while vehicles are in motion. The system would then be integrated under the road surface. Objective announced: recharge a vehicle at the speed authorized on the highway in the United States (between 90 and 120 km / h depending on the State).