In a few years, cars going down a road in a historic section of Detroit will theoretically be able to charge their batteries as they drive. That’s the goal of an Israeli company that is finalizing an agreement with the state of Michigan’s Department of Transportation to build the roughly one mile long experimental roadway.
The idea of car-charging roads has been around for years. If an electric car capable of wireless charging journeys on powered roads, the thinking goes, it would be able to drive with virtually unlimited range, its batteries never running out of juice.
But making it actually work has proven difficult. This would be the first publicly accessible road of its kind in the United States, according to Electreon, the company building the wireless charging road. Anyone will be able to drive on it, and it will be part of the normal street grid in the area near the historic Michigan Central Station.
For the vast majority of drivers in gasoline-powered, or even electric, cars and trucks, the road should seem like any other, according to the company, except that the pavement will be fresher right after it’s completed sometime in 2023.
Properly equipped electric cars – very few of which have been offered for sale publicly in the United States so far – will be able to charge their batteries as they drive over the road. Underneath the road’s asphalt surface will be a series of inductive chargers, a bit like the wireless charging pads used for mobile phones.
While wireless charging of electric vehicles is much more efficient than wireless charging of phones, in part thanks to better equipment and higher power, it’s still somewhat less efficient than charging with a cable, said Sam Abuelsamid, an electric vehicle analyst with Guidehouse Insights.
Before the road can charge very many vehicles, though, more cars and trucks need to actually have wireless charging capability. So far, very few do. Part of the reason for that, according to Abuelsamid, is that industry-wide standards for wireless EV charging have only recently been agreed to by groups like the Society for Automotive Engineers.
The other big reason is cost. Adding the equipment for wireless charging would add thousands of dollars to the cost of a car, he said. And the car would still need a standard charging cable port, too, because no one would want to be totally reliant on wireless charging. Also, of course, building the charging systems into public roads would greatly increase the cost of the road.
Besides being a center for the US auto industry, Michigan is a perfect place to test this sort of technology because of brutal conditions there that are hard on roads, according to Michele Mueller, senior project manager for connected and automated vehicles at the Michigan DOT.
“We have ideal weather scenarios and conditions all the way from sunny and hot weather to cold, well below zero, temperatures with snow and ice and all the different elements,” she said.
In addition to researching the road itself and allowing some vehicles to charge, the stretch of roadway will also be useful to companies that want to research and test wireless charging, Mueller said.
Electreon is working on charging road projects in European countries with similar weather conditions, said Stefan Tongur, Vice President of Business Development for Electreon in the U.S. Those projects are still in their early stages, though, with one in Sweden operational since 2018, according to the company’s website, and ones in Germany and northern Italy not yet running.
In addition to the road itself, Electreon will also be building “static charging” stations along the road where drivers will be able to park their vehicles over inductive chargers and charge wirelessly that way.
One of the benefits of wireless charging, Tongur said, is that unlike charging stations with cables, most of the equipment is safely buried under asphalt or concrete. That means it’s not subject to being run into by cars or trucks or having charger plugs driven over, said Tongur. There is a large box above ground for equipment that has to be accessible for maintenance, he said, but that will be out of the way of traffic.
Wireless charging can be efficient, Tongur claimed, with around 87% of the energy going into the underground charging coils making its way into the vehicle’s batteries while the car is driving. Efficiency is higher if the car is charging while parked, he said.