Drivers could one day charge their electric vehicles without having to stop and plug in, thanks to a breakthrough in wireless charging announced by Stanford engineers.
The US university team has been working on wireless recharging for moving objects since 2017, but has struggled to design a system that would be efficient enough to work in the real world.
Breakthrough
The team has hit upon a way of significantly boosting the efficiency of the technology by using a more efficient amplifier, according to an article by Stanford's engineering school. A new prototype is able to wirelessly transmit 10 watts of electricity over a distance of two or three feet within milliseconds - about enough electricity needed to charge a computer tablet.
Stanford electrical engineer Shanhui Fan said the system would need to be scaled up to work for cars, but predicted it could be more than capable of charging a speeding automobile within seconds. The technology is already advanced enough for recharging roving robots or drones, he said.
"This is a significant step toward a practical and efficient system for wirelessly re-charging automobiles and robots, even when they are moving at high speeds," Fan said.
"We would have to scale up the power to recharge a moving car, but I don't think that's a serious roadblock,” he added. “For re-charging robots, we're already within the range of practical usefulness."
The research is published in the journal Nature Electronics.
No more plug points
Wireless charging on the go is something of a holy grail for the electric vehicle industry. Such an approach could help eliminate so-called ‘range anxiety’, where drivers are put off purchasing an EV for fear of running out of charge before finding a chargepoint. It could also allow batteries in cars to be smaller, making electric cars cheaper to buy.
But installing charging technology on major roads would be a significant financial investment. To date only a couple of countries are experimenting with electric roads - notably Sweden, which opened the first electrified stretch of road in 2018. There, electricity is transferred from metal tracks to vehicles via an electric arm on a vehicles' undercarriage.
The US university team has been working on wireless recharging for moving objects since 2017, but has struggled to design a system that would be efficient enough to work in the real world.
Breakthrough
The team has hit upon a way of significantly boosting the efficiency of the technology by using a more efficient amplifier, according to an article by Stanford's engineering school. A new prototype is able to wirelessly transmit 10 watts of electricity over a distance of two or three feet within milliseconds - about enough electricity needed to charge a computer tablet.
Stanford electrical engineer Shanhui Fan said the system would need to be scaled up to work for cars, but predicted it could be more than capable of charging a speeding automobile within seconds. The technology is already advanced enough for recharging roving robots or drones, he said.
"This is a significant step toward a practical and efficient system for wirelessly re-charging automobiles and robots, even when they are moving at high speeds," Fan said.
"We would have to scale up the power to recharge a moving car, but I don't think that's a serious roadblock,” he added. “For re-charging robots, we're already within the range of practical usefulness."
The research is published in the journal Nature Electronics.
No more plug points
Wireless charging on the go is something of a holy grail for the electric vehicle industry. Such an approach could help eliminate so-called ‘range anxiety’, where drivers are put off purchasing an EV for fear of running out of charge before finding a chargepoint. It could also allow batteries in cars to be smaller, making electric cars cheaper to buy.
But installing charging technology on major roads would be a significant financial investment. To date only a couple of countries are experimenting with electric roads - notably Sweden, which opened the first electrified stretch of road in 2018. There, electricity is transferred from metal tracks to vehicles via an electric arm on a vehicles' undercarriage.