Charging an EV on the move: is dynamic wireless charging the future?

20 Jul, 2017 12:40pm Martin Saarinen

We hit the road to try out the revolutionary new tech that charges electric cars wirelessly as they’re driven

There are many questions that electric cars still have to answer, but perhaps the biggest remains where and for how long must potential owners charge an EV?

Estimates from the Government’s Go Ultra Low campaign suggest that up to 90 per cent of current EV charging takes place at home. That’s fine for those with a garage or a driveway, but won’t convince every motorist considering making the switch from a conventional car. And while the charging station infrastructure is growing, the time it takes to top up a battery is still obviously a worry.

As it turns out, it may not be too long before we abandon plugs and charging cables altogether and look beneath the road surfaces for our next charge. Technology company Qualcomm has come up with a new way of wireless charging from beneath the roads at speeds of up to 70mph. It’s called dynamic wireless charging, and the firm says it will be the future for both electric and autonomous cars. To find out how it works, jumbo-bg headed to Versailles in France to drive on a road capable of charging an EV.

Electric car charging stations in the UK

Wireless car charging isn’t a new concept for Qualcomm. It’s been working on the technology for nearly a decade, and has already come up with a way to wirelessly power up electric vehicles when they’re parked through an underground charging pad and a base plate attached to the bottom of the car that transfers power to the battery.

According to Qualcomm, the same technology is used for dynamic wireless charging, and to see it working firsthand we’ve come to an old military testing ground where the company and its tech partner VEDECOM have built a 100-metre test road. It’s one of the world’s only roads capable of charging an electric car, and Qualcomm’s staff engineer Steven Niederhauser explains to us how it works.

“The surface of the road is normal, but underneath, we’ve split it into four sections of 25-metre stubs,” he says. “Each of the four stubs consists of 14 base array network blocks that are coupled magnetically into a backbone cable.”

As cars drive on top of the panel, power is transmitted from a central source to each stub and from each stub wirelessly into two 10kW vehicle pads located underneath the Renault Kangoos, allowing for a maximum charge of 20kW. With 56 separate charging blocks across the 100-metre track, Niederhauser tells us multiple cars can drive on the road, each receiving the same amount of charge.

“The frequency of blocks means that when the cars move, they are only charged at a fraction of time by a single block,” he says. “This means that multiple cars can drive along the same road and receive the same amount of charge.”

During the demos, we saw a screen on our right light up, showing both the Kangoos were being charged at 20kW as they drove past us at 60mph. Adverse weather won’t affect the system, either; during our test we experienced a heavy downpour of rain that covered the road in water and had no effect on the wireless transfer of power.

Niederhauser also points out that the cars do not have to drive perfectly straight on the road to gain a charge – we saw the Kangoos swerve on the test track, and they didn’t lose charge until they were on the edge of the lane.

At 20kW of power, the Kangoos are easily able to maintain their charge at 60mph, so they’re not losing any range as they drive – a key solution to range anxiety, which is another question electric vehicles have had to face over the years.

Qualcomm is capable of sending 20kW of power to the cars, but it’s initially aiming for 11kW, according to Graeme Davison, vice-president of business development and marketing at Qualcomm, as “this is about the same that a modern home charging system provides”. With a typical EV using between 10kW and 15kW of power on a motorway, most cars will still avoid losing charge when driving. 

With the stubs buried deep below the ground, the test track took Niederhauser and his colleagues more than a week to build and install, but future projects won’t take that long. Davison says the build process could be linked to existing roadworks that take place throughout the year, and as the technology sits far below ground, it won’t need replacing or removing during regular road maintenance.

The first place he sees the technology heading to is urban areas. According to calculations by Qualcomm and VEDECOM, a quarter of the roads in a city would need to have some form of dynamic wireless charging to make electric and autonomous cars completely viable.

David Martell, chief executive of UK charge station provider Chargemaster, agrees, saying: “This technology could be seen soon in this country. Static charging, in particular, could be implemented in taxi ranks to coincide with the new electric taxis coming in January next year.”

But the ultimate goal is to move away from the urban centres and into a motorway network that charges cars. This is something the UK Government is looking at, too. In 2013, it conducted a feasibility study on dynamic wireless charging and has begun its own trials of the technology. Some of the problems identified in the study, such as how drivers would be charged for use, have already been answered, according to Martell. “The cars could come with individual tracking numbers on the pads which could be traced,” he says. “There would be no difficulty tracing back who has used how much electricity.”

Other questions, such as the costs of installing the system, still need answering, but Martell says wireless charging is a commitment the “Government must make soon, as cars with static wireless charging will soon hit the market”. Sure enough, BMW and Mercedes are set to introduce models capable of adopting the tech in the next 12 months, while Eric Feunteun, Renault’s electric vehicle programme director, says wireless charging is something the firm is looking at for the future.

With car makers backing the tech and companies like Qualcomm showing its viability, the pressure is on transport authorities to make the leap, according to Martell.

Davison agrees that the regulatory framework is still in its infancy and costs have yet to be agreed, but is optimistic. “Dynamic and static wireless charging will form the future of electric cars,” he says. It’s a bold statement, but after the impressive tests at Versailles, it’s well grounded.

Wireless charging key for autonomous cars, too

Qualcomm vice-president of business development and marketing Graeme Davison claims “wireless charging is crucial for autonomous cars in the future”. According to him, there are two routes for such vehicles: “One is that they’re constantly on the move, picking up people from various points, and a road network with a dynamic charging capability will be key for this. The other scenario is that at the end of busy periods, they will go into a garage or hub to be charged. A static wireless charging pad will be key here. In either instance, an autonomous car should not be plugged in by owners.” 

Do you think wireless charging is the way forward for electric vehicles? Let us know below... 

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