Currently reading: The road that charges your electric car
In 10 years, electric cars could charge wirelessly from the road as they drive along it
Julian Rendell
3 mins read
20 July 2017

Technology that will allow electric cars to top up their charge on the move is being readied for production in the next decade.

The ‘electric road of the future’ could be a reality sooner, but car makers will need to design the next generation of electric vehicles (EVs) to incorporate induction charging pads into their technical make-up. Road infrastructure companies, meanwhile, will need to install multiple numbers of pads under road surfaces to make the idea a reality. 

“Maybe ten years is a good timescale for this technology,” said Virginie Maillard, a senior Renault EV engineer. “We have to design cars and the road network to accept it.”

The third-generation Renault Zoe, for example, might be expected to hit the market in the mid-2020s, and Renault has a chance to futureproof the design for induction charging.

Induction charging technology is currently being investigated at a purposebuilt test track near Paris using Renault Kangoo ZE vans and Qualcomm Halo wireless induction charging equipment. Qualcomm, a huge US technology company, is better known as the designer of mobile phone chips.

Qualcomm will develop the technology and sell it as a licence to a tier one supplier, which will make it a production reality. Each unit sold will earn Qualcomm a royalty.

The charging system works using the principle of induced currents – the same technique that electric toothbrush chargers deploy.

An electrically live coil is buried under the road, and when a car equipped with another coil passes over it, it induces a current in the car’s coil. This feeds into the EV’s battery and keeps it topped up.

Although the car passes over the pad buried under the road in fractions of a second, up to 20kW of energy can be pulsed into the EV, which car be travelling at speeds of up to 60mph. That’s about the same amount of energy that an EV uses when cruising.

Qualcomm’s engineers claim that enough energy can be passed to an EV to keep it moving at that speed without depleting the battery, so charge can be maintained to be used at other locations where there is no induction charging.

Ultimately, a complete road network could be equipped with induction pads, allowing EVs to travel distances unlimited by battery capacity. Research suggests that if 250 metres of every kilometre of motorway was equipped with wireless charging, an EV could travel without depleting its reserves.

The trial in France will examine all the extremes of operation, including coping with wet weather, vehicles passing over the coils out of alignment by up to 50%, variations in the power supply and the durability of the hardware during extended use.

Qualcomm has already programmed the wireless system to reduce the pulse of energy to 5kW when traffic is moving along the road at a stop-start pace.

Renault will also look at the integration and durability of the coils and an in-car black box, which is needed to smooth out the signal of the induced current to match the electrical system in the test vehicles.

Car firms in plea to China over electric car sales quotas


Find an Autocar review

Read our review

Car review
Renault Zoe

Bespoke battery-powered supermini aims to advance the cause of electric cars at the mainstream end of the market

Back to top

Join the debate


20 July 2017

Just won't happen. Not feasible.

1. To make even a small section would take a fortune of cabling, infrastructure, road side boxes hooked up to the wider grid, roads re-laid etc.

2. The wider the gap the bigger the loss, car would need to have the pickup coil very low, bye bye beloved SUVs, they have have been able to transfer a momentary 20 kw but that is a very different thing to 20 kw/h. The only way it could work at any speed is to transfer a huge burst charge, the car would have to be able to take a huge 'shock' charge instantly without blowing up.

- It could have some use at maybe a traffic light approach, perhaps on a multi lane one the inside lane could have its own light control and be designated an EV lane. When an EV is detected the lights for this lane slow by missing out alternative Green cycles giving the EV 5 -10 minutes rapid charge time.  

What people really want is this technology for stationary charging, car parks, home driveways - I meet people who think flipping a flap and clunking a connector in is tiresome, after 2 years I hardly notice but being able to just park over a pad would be nice.

20 July 2017

have a pacemaker in the future.

20 July 2017

There's also parked inductive charging which to me is a more realistic proposition. I can see having an eleccy car that charges without trying to find the one charging point available, then traipsing a plug across the pavement, would be a big incentive to using one every day.

20 July 2017

1) Huge electro magnetic fields at the current and voltage required.  2) the efficiency losses charging this way will be enormous when multipled by the amount of cars we have now although if the coils couls manually be placed then perhaps better efficiency would be possible. And let's not forget the additional 20 nuclear power stations required.

20 July 2017

Self charging Cars, autonomous Cars, what if you want to drive?,what happens once you leave a charging Road?, will we indeed need to actually own a Car,these are just a few questions I'm sure some of us want to know answers to, a more important question is, having systems take over what we perceive as mundane a good idea?, making Transport as taken for granted as a ballpoint pen might also damage the Car industry because we might not need to buy a Car, also the other associated business connected to Transport, insurance,road tax,servicing these ar just a few that might suffer.

20 July 2017

Maglev for motors! Get into the fast lane on a motorway and your family car can match any hypercar as it is fired down the highway by electro magnetic pulses!

On a more serious note, this idea might be of more use to extending the viable distance of low/zero emission vehicles than under lane induction charging...

20 July 2017
Electric cars are great bits of engineering now and they have their place. But the obsession with them by many people including politicians is becoming a bit infuriating. In the UK transport as a whole is responsible for about 25% of carbon emissions, of which a large amount will be from HGVs etc. On the other hand heating and cooling buildings is responsible for nearly 40% of carbon emissions. Why don't we deal with the biggest issues first? All buildings could be heated and cooled with a combination of solar thermal panels and electric air source heat pumps. Almost all buildings are already connected to the electrity grid so deployment is easy. Until such times we have enough carbon free electrity generation for that extra load we should stop just focusing on electric cars.

20 July 2017

Wireless Scalextric at 1:1 scale. It is like a childhood dream. On a more serious note, this would only be needed on motorways and out of town A roads, normal charging copes with most other situations.

20 July 2017

Let's say that the technology can be made to work reliably, why not,

the questions then are:

1/ where does the money come from to 'electrify' thousands of motorway miles initially, and then many more thousands of a-Class roads?

2/ How long then before payment is made by some transponder read by the devices (again, we take it that it is technically feasible): who determines the amounts to pay? On what basis? What about foreign vehicles? What when someone claims a fault in their transponder, etc? We have a similar system here to collect motorway tolls and it is only beginning to settle after years of cock-ups! And Portugal has very few motorways...

3/ What happens during the necessary road-works? Even one lane at a time will take a considerable length of time: will the M1, M4, M6 turn into giant car-parks?

Having shown enough cynicism for one day, I shall now drive my petrol little car to a dealership and ask what trade-in I can get against a Hybrid; could be interesting to compare with another petrol car... 

21 July 2017

Potholes go for years without filling, but governments are going to find the time and the money to electrify the road network. Yeah, right...

Parking spaces, as was pointed out above, are a much cleverer bet.

Add your comment

Log in or register to post comments

Find an Autocar car review