Cordless charging of e-vehicles in the air

New device wirelessly transmits electricity to moving objects

Life on the run — unplugged.

That long-sought dream is closer to reality, thanks to a new device developed at Stanford University that wirelessly transmits electricity to moving objects, promising to transform our battery-powered future.

If the technology can be improved — boosting its power and extending the distance electricity can be wirelessly transferred — it would extend the range of electric vehicles, untether robots and end our constant prowl for electri- cal outlets.

“You can imagine being able to charge a cellphone or a car without a wire,” said Shanhui Fan, a Stanford professor of electrical engineering and senior author of the new research, published in the latest issue of the journal Nature.

“What we have done is a significant step forward in thinking about how to transfer energy to a moving object,” he said.

So f ar, only a tiny one-milliwatt charge has been sent to a mobile LED light bulb.

The bulb’s brightness remained constant as the receiver moved one metre away from the source.

This could be handy if there’s a wireless charge near your device in a taxi, at a restaurant, on the train or in line at the supermarket. But electric cars can demand tens of kilowatts of power. And they’re speeding down roads.

And those technical challenges temper the enthusiasm of some consumers.

“My take on the research: very exciting, but only relevant to small consumer electronics in the near future,” said Palo Alto’s Ben Lenail, director of business development at the solar energy company Alta De- vices. “Yes, it could allow users of mobile devices — cellphones, connected health devices, fitness and activity trackers, various wearable gadgets — to cut the cord completely,” said Lenail, who has two Teslas. “But electric vehicles need a huge charge.”

The Stanford team, however, believes it can boost the amount of electricity that’s transferred. It also aims to extend distances and improve efficiency by tweaking the system.

If our highways are updated, with electric current embedded in roads, “you’ll be able to charge your electric car while you’re driving down the highway,” Fan said.

That would transform the car in- dustry, perhaps making electricity the standard fuel.

The best we have now is the Chevy Bolt and Tesla’s upcoming Model 3, which travel about 320 kilometres on a charge and take hours to fully re-juice.

“It would actually be revolutionary because it proposes something that is not possible today — charging while driving,” said Jon Foster of Palo Alto, a tech executive and former chair of the Palo Alto Utilities Advisory Commission.

“It would address the two key challenges for electric vehicles: limited battery range and the cost of the battery,” he said.