Now that there's an industry standard, automakers are starting to deploy the tech.
A rendering of a public wireless charging station. In fact, WiTricity expects most wireless chargers to be installed in homes.
WiTricity
In our recent explainer on electric vehicle charging, you might have noticed that we didn't mention wireless EV charging. Now common on smartphones, wireless charging works the same way on cars, just at higher power levels and with much bigger batteries. But after some demos and news releases during the mid-teens, the technology seemed to fall off the radar.
Behind the scenes, though, engineers were hashing out an industry standard, aided by industry consolidation along the way. That's now final, and the first EVs with factory-fit wireless charging systems are starting to appear, albeit not here in the US just yet. But given its ease of use, even for drivers who can't imagine life beyond the gas pump, the potential for adoption seems good.
Ars got its first look at wireless car charging back in 2015. Back then, chip-maker Qualcomm was developing what it called Halo, which it was demonstrating at Formula E races by recharging the battery in a safety car, a BMW i8 plug-in hybrid. It wasn't the only outfit developing wireless charging, however. In Massachusetts, an MIT spinoff called WiTricity started playing around with wireless car charging in 2010 after an investment by Toyota.
Now there’s a standard
"We fully engaged in a new standards group that was set up at the SAE—the Society of Automotive Engineers—to set a global standard," explained Alex Gruzen, WiTricity's CEO.
"So the view was that cables had been such a mess—different automakers, different regions, different connectors, cables, and standards," he told Ars. "And they said, 'Look, if wireless is the next thing, let's just do it once. Let's do it as one global standards organization led by the SAE.' So all the automakers started engaging, and the primary technology providers in that standards effort were WiTricity and Qualcomm Halo. And I think in some ways, each company advanced the technology, but in a lot of ways, we had different architectures, and I think it showed some confusion and really slowed things down."
But in 2019, WiTricity acquired Halo and spent the next year integrating the best aspects of each system. "By October 2020, it was ratified and done," Gruzen said. "So once we did the acquisition, we came to the industry with one proposed architecture, and frankly one IP portfolio that anyone could license, and consolidated the IP from WiTricity and Qualcomm. Less than a year and a half later, [the standard] was ratified and done and automakers are off to the races to start producing vehicles."
Already deployed in South Korea and China
A very early example is the Genesis GV60, a rather advanced electric crossover that has recently gone on sale here in the US. Sadly, wireless charging is currently only available in the GV60's home market of South Korea. Genesis is installing wireless charging pads at Genesis-branded charging stations, but Gruzen said the majority of charging pads will be destined for home garages and carports, not public infrastructure.
China may well lead the way. "[Its] car market has gone electric. So once it's almost default that your next car is going to be an EV, the automakers have to find ways to differentiate since at the end of the day, they're all the same batteries and inverters and motors, for the most part. User experience features and design start to matter a lot," he explained. Three automakers have already started offering wireless charging as a feature in China, with more set to join in 2023.
No major efficiency losses
Gruzen dispelled the idea that wireless charging is inherently much less efficient than using a wire. "When we talk about our system, we talk about them as being 90–92 percent efficient," he said. "But that's end to end; that's from the grid all the way to the battery of your car. And if you were to look at the equivalent for plug-in charging, it tends to be in the mid- to high-80s; [for] the best in the market, it's been about 94–94.5 percent. So we're right in the sweet spot."
"Part of that is because everything that plugs into the grid needs its own isolation transformer," Gruzen continued. "We have a natural one; we have an air gap. So effectively, our two coils—the one on the ground and the one on the car—act like a transformer [and] give us the isolation naturally, and then all the rest of the electronics are pretty much the same—you're going from 240 V and 60 Hz and having to end up at whatever the car needs voltage-level in DC."
Higher power rates than 3.3–6.6 kW are also possible—WiTricity has developed a 75 kW system for recharging commercial EVs. "It's not a technology limitation; it's designed for purpose. For passenger cars, it's about making it small and making [it] appropriate for the power you have at home primarily, which is Level 2. That's the design focus. So the SAE standard focused first on that because that's the usage model," Gruzen told Ars.
And yes, an F-Zero-style road that recharges an EV while it drives is also theoretically possible. In 2017, WiTricity built a test track in Versailles, France, that allowed a van to charge at up to 20 kW while driving at 62 mph (100 km/h). But as battery prices have fallen, the economics of making wireless charging roads doesn't appear to make much sense beyond low-speed applications like taxi queues at stations or airports or drayage trucks hauling shipping containers at ports.
And there's nothing inherently directional about the technology, so while the first implementations are just for charging a car from the grid, expect vehicle-to-grid abilities to be enabled once wireless charging EVs start showing up on US roads. That should be sometime around 2024–2026 if all goes to plan.
Easier than a plug: Wireless EV charging gets ready for prime time
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