Wireless Charging for Electric Cars

By
Laurance Yap
Updated:
Mar 2022
Time to Read:
3
min
If you have a mobile phone made in the last couple of years, it probably has the ability to charge wirelessly. Soon, you might be able to do the same with your car. Here's how wireless charging works.
White Electric SUV in a Parking Lot

Wireless Car Charging Has Arrived

If you have a mobile phone made in the last couple of years, it probably has the ability to charge wirelessly – at home, at work, or even in your car. Now, having to plug in a cord to charge your smartphone seems massively inconvenient compared to parking it on a pad where it juices itself up, and where you can just pick it up when needed. Imagine if the same were possible for your car: no fumbling around with heavy charging cords, no having to worry about charge port doors freezing shut in the winter…simply park and walk away, while your electric vehicle rejuvenates its charge.

Wireless EV charging is indeed possible, and it is indeed for real. A number of vehicles in the Asian market are already available with wireless charging as an option, including the FAW HongQi E-HS9, and the Genesis GV60, which will soon be available in North America. The technology has yet to make its way to our shores, but we suspect its introduction isn’t far away, once regulators have had a chance to approve the systems for safety. And like when wireless charging for mobile phones was introduced, EV wireless charging may be a game-changer.

How does wireless charging work? In much the same way as wireless charging for your phone. A wireless ground pad can be installed, or positioned, where a vehicle is parked, and the vehicle receives a wireless vehicle pad, installed on its underbody. The ground pad and the vehicle pad convert alternating current (AC) to a magnetic field that transfers power over the gap between the two pieces. Using specially-designed low-loss resonators means that the coil-to-coil efficiency between the two pads is somewhere over 95%. On board the car, the vehicle pad is connected directly to the vehicle’s rectifier, which converts the AC current to DC to charge the vehicle’s battery.

Current wireless charging systems operate with power outputs and speeds roughly equivalent to level 2 plug-in charging, which would make them potentially a more convenient replacement for a home plug-in charger. Similar to a home plug-in charger, a wireless EV charger would still need a 220-volt dryer-type outlet to plug into, so installation costs would be roughly the same.

Retrofit Option for Older EVs

If you currently drive an electric vehicle, you may be able to retrofit wireless charging to it in the future. A company called WiTricity, based in Massachusetts, has unveiled plans for an aftermarket wireless charging solution it calls Halo. WiTricity currently has a Tesla Model 3 fitted with a prototype Halo system, and is also upgrading a Ford Mustang Mach-E with wireless charging – and more to come.

The Halo package delivers 11-kW wireless charging – a little bit faster than typical 7.2-kW level 2 plug-in charging unit, which provides 35-40 miles of driving range per hour of charging time. The upgrade includes a power receiver installed on the vehicle, a wall box to connect to electric power, and a charging pad that can be installed on-ground or in-ground. Using Halo, a Tesla Model 3 fully charges in less than six hours.

WiTricity says that the Halo system, which has been awarded numerous patents, will become available to owners for select EVs in late 2022, with broader availability in 2023. Which vehicles will be supported will be based on customer demand, as well as automaker support. Individuals interested in upgrading their car for wireless charging can sign up on the tech company’s website.

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