Here's a look at latest technological advances made by two companies operating in the wireless charging sector for EVs, demonstrating how this technology is ever closer to achieving large-scale adoption.
The gradual, but by now unstoppable, growth in the number of electric vehicles (EVs) requires the availability of charging systems that are increasingly efficient and fast. Solutions aimed at reducing the time required for EV recharging, such as ultra–fast charging and HV batteries (800V or higher), have already been implemented on some vehicle classes and will be increasingly widespread in future.
An alternative solution, able to simplify and optimize the charging process, is certainly wireless charging, which can be used both with the vehicle in motion and with the vehicle parked. This article will present the latest technological advances made by two companies operating in the wireless charging sector, demonstrating how this technology is ever closer to achieving large–scale adoption.
Electreon, a provider of wireless charging solutions for EVs, has successfully tested its dynamic wireless charging technology at the “Arena of the Future” test track (Figure 1), powering a Fiat 500 EV and an Iveco electric bus.
According to Stellantis, the parent company of Fiat, the 500 EV was able to travel at a typical highway speed without drawing energy from its battery pack, thus extending its range. Similarly, driving at a lower speed, the vehicle might be able to restore some of its charge.
The Dynamic Wireless Power Transfer (DWPT) technology developed by Electreon is based on conductor loops that are deployed under the asphalt and transmit the energy to the receiver plates of the EV using the principle of magnetic induction. The receiver plate can be installed indifferently on an EV, an electric bus, or an electric truck. To limit power losses and facilitate integration with renewable energy sources, the technology uses DC electricity. Compared to AC charging, this solution allows you to use thinner cables, reducing costs and simplifying the thermal management.
“Conventional charging stations using conductive cables are not scalable. The only option that I see is wireless charging, since it can be deployed almost everywhere. It can be on the road, on the side of the road, inside terminal, loading, dock, and it can be directly connected to the grid 24/7”, said Oren Ezer, CEO at Electreon. As Ezer states, wireless charging can be deployed everywhere because you do not see it and it has no visual impact.
When Electreon was established, there were just a few companies dealing with wireless charging, and a few OEM carmakers employing that technology in a pilot project. Today, all the carmakers can show some demo or pilot project where they are testing the wireless charging technology.
“You can see the shift from new technology to obvious technology, and wireless will be very dominant within a few years”, Ezer said.
The test performed in Chiari demonstrated, for the first time, a private passenger EV and a vehicle bus driving on the same platform and receiving energy simultaneously while driving on the road. The test started with the Fiat 500 at 22% SOC (State of Charge), and after a few laps, the battery SOC went up to 48%.
“I’ve been dealing with wireless charging for almost ten years, and I’m amazed each time I see this. You drive the vehicle, and instead of losing energy, you gain energy”, Ezer said.
When approaching a new project, Electreon starts optimizing the route followed by the vehicle. If, for instance, we know that the bus stands for five minutes at the beginning of the route, and then after the round trip, it enters the terminal for five–minute break, we can calculate the route knowing that we have 10 minutes of waiting. Assuming we have 30 minutes of driving, we can electrify both terminals, including 10% of the route, providing the bus enough energy to drive 24/7.
“A similar use case refers to taxis, giving them the ability to charge while they’re waiting for passengers. Actually, you don’t need to electrify miles or kilometers, you can just electrify specific areas like relief stands”, Ezer said.
WiTricity, another provider of wireless charging solutions for EVs based on its patented magnetic resonance technology (Figure 2), gives us its opinion on the current state of wireless charging technology and future prospects.
“Several things are driving interest in wireless charging for EVs and consumer demand is a key one. We recently ran a survey that showed 96% of EV buyers want wireless charging. As more consumers purchase EVs, it’s incumbent upon the industry to promote ways to create easier, hassle–free ways of charging their vehicle, free of plugs”, said David Schatz, vice president of Product Management at WiTricity.
According to Schatz, wireless charging is being pursued by EV makers and charging infrastructure providers to provide seamless interoperability. Wireless charging eliminates the charging cord and the charging connector, enabling the carmaker to avoid the pitfalls of multiple charging standards and offering EV owners a more seamless charging experience.
Other key factors that drive the demand for wireless charging are reliability and maintainability. While charging cords and connectors are subject to failure, damage from dropping and vandalism, and are difficult for people with physical disabilities to handle, wireless charging makes charging simpler for everyone.
“Asian car makers are the first to adopt wireless charging as a key feature to differentiate their vehicles. China’s FAW brand introduced the Hongqi EHS9 luxury SUV with wireless charging in 2022, and Hyundai’s upscale Genesis brand introduced the GV–60 SUV with wireless charging in South Korea. New technology features like wireless charging are usually introduced first on upscale vehicles, and then migrate into mainstream vehicles, Shatz said. “Our licensed Tier 1 partners and we are engaged with carmakers around the globe to make wireless charging become the preferred method to charge EVs at home, at work, at retail and other commercial establishments.”
WiTricity has recently received a $25 million investment from Siemens, one of the leading global electrical infrastructure suppliers, and expects that their presence in the market will accelerate the adoption of wireless charging. In addition, Witricity has announced the Halo Upgrade Program, with which existing EVs will be updated with wireless charging capabilities, and WiTricity’s wireless chargers will be provided for installation at commercial sites and private residences in target markets.
As Schatz points out, an all–too–common misconception is that wireless charging isn’t efficient. “Our 11kW system is up to 92% efficient, which means it is as efficient as a level 2 plug–in”, Schatz said.
Public investment in charging infrastructure will be a major driver of the widespread adoption of EVs, and of the adoption of wireless charging.
“In urban areas, many people park on the street—and installation of millions of wired charging stations on city streets is really problematic. Wireless charging built into the street itself with all of the infrastructure buried or hidden is a much better approach to deploying EV charging on city streets,” Schatz said. “Governments around the world are allocating massive funds to deploy chargers as one way to encourage individuals and companies to shift to electrified vehicles and electric utilities and even traditional oil companies are investing heavily to build out the charging infrastructure to enable the electric vehicle future, and a growing share of that infrastructure will be wireless.”
This article was originally published on EE Times.
Maurizio Di Paolo Emilio has a Ph.D. in Physics and is a Telecommunications Engineer. He has worked on various international projects in the field of gravitational waves research designing a thermal compensation system, x-ray microbeams, and space technologies for communications and motor control. Since 2007, he has collaborated with several Italian and English blogs and magazines as a technical writer, specializing in electronics and technology. From 2015 to 2018, he was the editor-in-chief of Firmware and Elettronica Open Source. Maurizio enjoys writing and telling stories about Power Electronics, Wide Bandgap Semiconductors, Automotive, IoT, Digital, Energy, and Quantum. Maurizio is currently editor-in-chief of Power Electronics News and EEWeb, and European Correspondent of EE Times. He is the host of PowerUP, a podcast about power electronics. He has contributed to a number of technical and scientific articles as well as a couple of Springer books on energy harvesting and data acquisition and control systems.
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