Transport

New technology that could allow electric cars to charge as they drive

Could ‘magnetised concrete’ be the solution to long-haul EV driving?

A Renault Kangoo trialling a digital wireless road surface designed to help power electric vehicles

Neil Briscoe's face
Neil Briscoe
Thu Sep 9 2021 - 05:26

When electric cars first started appearing on Irish roads, the joke was that you’d need a long extension cord if you were planning to drive to Cork.

Like most bad jokes, there was a kernel of truth in it. Batteries were small, and charging infrastructure was all-but non-existent.

Things have changed, and dramatically so. There are now affordable electric cars on the market that can go for 400km, even 500km on one charge of their batteries, and the national charging network has been expanded.

While there are certainly more chargers now, there are also many more electric vehicles (EVs) on the road, and the problem of having to wait and queue for a charger is still an issue for those undertaking longer battery-powered journeys. Equally, while faster, more powerful chargers are starting to appear, they’re still quite rare (especially once you’re outside of the greater Dublin area), and those cars with bigger batteries take longer to charge.

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In spite of being a senior spokesperson for environmental matters for the UK government, Allegra Stratton shocked more than a few when she said in an interview that: “Right now, if I had [an electric car], any of those journeys to my dad in south Scotland, my mum in Gloucestershire, my in-laws in the Lake District and my gran in north Wales, they’re all journeys that I think would be at least one quite long stop to charge.

“And my kids are seven and four and I don’t fancy it just yet. Sometimes when you’ve got a four-year-old in the car, they’re asleep and you just want to keep going to get there because you know, if they wake up they’ll want the loo, they’ll want food, they might be feeling carsick and so on.”

Unsurprisingly, Ms Stratton’s statements came in for a tirade of abuse, but as with the old, bad jokes about extension cords there was a kernel of truth to them. While EV life is improving all the time, it can still be more awkward, and require more planning, than driving a combustion car.

Obviously, that awkwardness and need to plan is as nothing compared to, say, destroying the planet, or emitting disgusting, dangerous exhaust fumes into the faces (and lungs, more to the point) of passing pedestrians, but surely even the most ardent EV advocate would admit to sometimes wanting to take the easier route.

Magnetic concrete

Perhaps soon, we might not have to. The easier route might actually be the electric one because, just possibly, there’s a way to charge an electric car as it drives.

Now, this is not a plan to fit trolley-bus-like arms to the tops of cars, that would reach up to an overhead network of cables. It is much more clever. It’s about using magnetic concrete to charge your battery as your car drives over it.

Sounds daft? Maybe so but tests are currently getting underway in the US state of Indiana, thanks to a team of researchers from Purdue University, the Indiana Department of Transport, and the team from German company Magment.

The technique being used by Magment is to add little particles of ferrite – essentially recycled slivers of iron and steel – into a concrete mix. That concrete is then, effectively, magnetised and if you run an electrical current through it, it can act as an inductive charger – just like the one you use to wirelessly charge your phone. In theory, if you attach a plate to the bottom of a car, that charge can then pass to the vehicle and top up the battery.

Magment claims that its charging concrete pads can handle power as low as 200-watts, or 200kW, which would make for a very rapid charge indeed. The plan now is for Purdue and Magment to see how all of this works in the real world.

“The field of transportation is in the midst of a transformation not experienced since the invention of the automobile,” Nadia Gkritza, professor of civil engineering and agricultural and biological engineering and Aspire campus director at Purdue University said. “Through this research, we envision opportunities to reduce emissions and near-road exposures to pollutants, coupled with other transportation innovations in shared mobility and automation that will shape data-driven policies encouraging advances.”

According to Mauricio Esguerra, chief executive of Magment, this project is a real “step forward” towards the future of dynamic wireless charging and will “undoubtedly set the standard for affordable, sustainable, and efficient transportation electrification”.

It’s not just a matter of convenience, either. Obviously a big part of the draw of developing a road that can charge a car passing over it is that you don’t need to stop on a long journey to recharge, which is nice. There’s a far bigger picture to see, though, which is the use of resources.

Expensive

Batteries are big, heavy, and expensive to make. Expensive not just in monetary terms (they are starting to become a little more affordable) but also expensive in environmental terms. Lithium, cobalt, manganese, nickel – all are critical to battery construction, and all must be mined. That mining brings its own environmental and energy-use issues, not to mention deeply disturbing questions over the possible use of child and slave labour in less-well-regulated countries, rich in such mineral deposits.

Then there’s the use of energy – renewable or otherwise – to physically construct the batteries. Polestar, Volvo’s all-electric and high-performance offshoot brand, has estimated that because of that energy use, you need to drive an electric car for more than 70,000km before it’s “in credit” as far as carbon emissions are concerned, compared to a petrol car.

Imagine, then, doing away with those problems, or at least minimising them. We could create a new generation of electric cars that don’t need massive batteries to travel for long distances, but instead could use smaller, lighter, power packs which are fine for short journeys, and which can be topped up as they drive on longer ones.

“We have to rethink our energy systems,” says Virginie Maillard, the head of technology for Siemens in the US, who in a former life was research director for Renault, where she experimented with early charging-while-driving tech.

“The race to produce the biggest battery is drawing to a close. Batteries are becoming too difficult to manufacture, or too heavy and bulky to be fitted into vehicles. So we are looking for new ways to balance our use of energy, which will involve shifting the focus of a car’s range towards charging and infrastructure rather than the energy on board the car.

“Meanwhile, as the European electric vehicle market continues to grow, the aim is to offer an alternative to conventional recharging stations, and to compensate for the limited number of such stations, as well as the time needed for a complete recharge. Those are the main obstacles to the use of electric vehicles, after the question of range,” she said.

There is still much to be proven where this technology is concerned. How robust is it? How safe? Do we need to start digging up roads to install magnetised concrete and laying electrical cables? If so, what environmental impacts does that have? How much would all that cost?

It’s a tempting prospect, though.