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Imagine vehicles connected to electric rails placed in the middle of traffic lanes and which therefore recharge effortlessly, simply by driving. This is precisely the concept of the eRoadArlanda, a two-kilometer stretch specially built for this purpose in Sweden and tested since 2018.
To be able to recharge while driving, vehicles must be equipped with a kind of pad placed at the end of an arm mobile attached to the bottom of the chassis, which automatically attaches to the rails arranged in their path. Initially, this system is being tested on trucks, but the idea is of course to be able to adapt it to buses and electric cars. The arm actually senses when the vehicle is over the rail and then automatically docks there. Similarly, in the event of a change in trajectory or overtaking, it “disconnects” without action by the driver.
This project is part of the Swedish government’s plan to establish a transport system completely fuels fossils by 2030. This type of road should be extended in the country, with the objective of electrifying up to 2,000 km of tracks by 2030.
A solution that is emulated
It might also give ideas to others, although so far the charging systems experienced from the ground are essentially induction. At the start of the year, the group Stellantis thus announced that it was testing an advanced transfer technology in Italyenergy wireless and inductive for electric cars, on a circuit specially created for this type of test. In this case, it foreshadows the type of infrastructure that could equip certain roads in the future, thus making it possible to gain considerable autonomy. It is in fact a technology based on a succession of loops placed under the asphalt which transmit energy directly to the vehicles driving over it. However, each vehicle must be equipped with a dedicated receiver, responsible for transferring energy from the road infrastructure directly to the electric motor. On the same principle, in Karlsruhe, Germany, a whole stretch of road will be equipped, over a few hundred meters, to supply energy to the city’s electric buses while they are driving.
For its part, the Spanish company Premium PSU has unveiled a brand new system intended to recharge its car by placing itself directly on a dedicated station, knowing that this system works both with the vehicle stationary and in motion. Note that in 2018, BMW had also released its own wireless charging solution when stationary, for plug-in hybrid vehicles of the brand. By induction or with the help of a skate, the solution to boost the autonomy of electric cars will therefore perhaps one day pass by the road itself.
eRoadArlanda, the first road that charges electric cars
Article of Marc Zaffagni on 04/16/2018
Sweden has just inaugurated a two-kilometre stretch of road that incorporates a system for recharging electric vehicles while driving. Inspired by the tram, this device will be tested for two years in real conditions.
In 2030, Sweden has set itself the goal of no longer usingfossil fuels for transport. To meet this ambitious challenge, the country will notably accelerate its adoption of electric vehicles. And, to facilitate this movement, the battery charging infrastructure must be not only dense but also complementary. It is in this perspective that has just been inaugurated what is presented as the first electrified road in the world designed to charge electric vehicles while they are in motion.
eRoadArlanda, that’s its name, is a stretch of two kilometers which consists of an electrified rail embedded flush with the road in its central part. Vehicles connect to it by means of a mobile contactor pad housed under the chassis. The latter is managed by sensors and deploys only when the rail is detected. And if the driver has to overtake or in the event ofaccident, the skid retracts automatically. Connected to the ground, the electrified rail sends current over short sections as the vehicle passes.
Sweden has 20,000 km of roads
This system is a derivative of that used by certain trams, particularly in France. eRoadArlanda connects Stockholm-Arlanda Airport to the Rosersberg logistics area outside the capital. For the moment, only one electric truck from PostNord will use this section during this test, which is scheduled to last two years.
If successful, the Swedish transport administration plans to extend the network to motorways and major roads. According to eRoadArlanda, the cost of deploying this system over the 20,000 kilometers of the Swedish road network would be 7.6 billion euros. But, thanks to the 3 billion euros in savings annual in energy fossilsthe electric road would be amortized in just under three years.
Will electric cars soon be powered by the roads?
Initial article by Quentin Mauguit, published on 07/11/2012
An original solution is being developed in Japan to booster autonomy of electric cars. The idea is relatively simple: couldn’t we permanently transmitwireless electricity through the roads, in particular thanks to an induction system? The first tests are in any case conclusive.
Most of electric cars current ones suffer from a reduced autonomy and above all from a recharge time very long. Many teams around the world are therefore working to reduce these limiting factors as much as possible. One of the solutions considered would be to provide real-time power to moving vehicles via the roads and therefore through tires, But how to do it ? A first part of the answer was provided last year by Toyota Central R&D Labs and Takashi Ohira, from Toyohashi University of Technology (UTU). During a workshop organized in Kyoto, they demonstrated that it was possible to transmitwireless energy between two metal plates traversed by currents in opposite directions and specially adapted tires (they are notably belted with parts ofsteel included inside the rubber and capacitors). The amount of energy lost in the rubber was also tested on this occasion. It would be, according to the figures of the time, less than 20%.
However, the installation of steel plates on all our roads could pose many safety and grip problems, especially in the event of rain. Improvements have therefore been made to this project, named Ever for Electric Vehicle on Electrified Roadway (electric vehicle on an electrified road).
A transfer of electricity through concrete
Its evolutions, presented in the magazine Tech-Onwere unveiled on July 5 and 6, 2012 during the Wireless Technology Park 2012 (WTP), a fair showcasing the latest wireless technologies. The demonstration speaks for itself. Two full-size tires were placed 10 cm apart concrete (used in Japan in the road construction), itself positioned on plates of metal traversed by a current. A ampule was then hooked up to the two wheels and…it started to shine.
Wireless electricity transfer is based in particular on the use of inductive coupling. The conductive elements traversed by a current (for example the metal plates equipped with suitable devices) are surrounded by a electromagnetic field. However, this can induce an electromotive force when it cuts a second conductor (such as the steel contained in tires). The feat of the researchers is to have managed to use this property through concrete, while ensuring that large amounts of energy can be transferred. An electrical power, that is to say the product of the intensity of the current by the electrical voltage, of 50 to 60 W has in fact been measured at the terminals of the bulb. The efficiency of the energy transmission to the tires would again be greater than 80%, even 90%, according to Takashi Ohira.
The team will now attempt to increase the thickness of the concrete through which current can be induced in the tires. These developments are very interesting but the electric power transmitted by the device would have to be multiplied by 100 before a car could drive on the highways without having to perform stops refills…
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