The biggest problem with electric cars is still their range and slow charging. Despite Tesla’s superchargers breaking records, charging times are much slower than refueling times for gasoline.
Well, a new wireless charger for electric vehicles can fill a car’s battery with the same efficiency as a plug with a cable, with an innovative power of 100 kW, which opens up the possibility of fast, efficient, and very convenient charging by simply parking in a designated spot.
Wireless energy transfer was first demonstrated in the 1890s by Nikola Tesla. Nowadays, it is quite common in many households, where many people use wireless charging pads for phones, tablets, and electric toothbrushes, as well as induction cooktops.
Energy is transferred from the charger to the device through the interaction of electromagnetic fields, and what was once considered black magic is now considered a safe, convenient, and efficient way to get the job done.
However, it has not taken off in the world of electric vehicles, mainly because power levels have kept it out of the realm of fast charging. One of the fastest wireless charging pads available on the market for electric vehicles is the 12 kW Hevo pad.
It’s better than a wall socket; it’s a level 2 charging speed and would give you around 68 km of driving per hour with an average efficiency electric car (5.6 km/kWh). But it’s not what you would expect from a commercial charging station.
A wireless charger that charges the car in one hour
The researchers at ORNL claim to have demonstrated the fastest and most powerful wireless charger for electric vehicles in history, with a “lightweight design of polyphase electromagnetic coupling coil” that transfers energy more than eight times faster than the Hevo pad, enough to charge the same car about 563 km in one hour.
In the test, a receiving coil was installed in a Hyundai Kona EV, which was parked over a 14-inch diameter polyphase transmitter, with a five-inch air gap between them. The system was measured at 100 kW, with an efficiency of 96%, comparable to what would be obtained with a very good cable and plug.
Researchers point out that, in a laboratory test, conventional coil technology has transferred a power of 120 kW, but they claim that this is the best ever tested in a car, and that the design of the polyphase coil allows to obtain the highest power density in the smallest possible coils, making the system relatively compact and convenient.
Of course, for any wireless charging solution – including the one integrated into the road surface – to gain momentum, many things have to happen, starting with car manufacturers setting standards and incorporating receiver coils and charging equipment into their vehicles.
This is a situation that is biting its own tail: few manufacturers are installing the coils, since few companies are building the infrastructure on a large scale, and vice versa.
