If you had to name one of the biggest game-change moments that the electric vehicle could bring to the world, try this one:
That's the vision of Jeff Muhs, director of Strategy and Business Development for Utah State University's Energy Dynamics Laboratory (EDL), whom we spoke with at the 26th Electric Vehicle Symposium (EVS26) in Los Angeles recently. Dynamic charging is another way to say charging while a vehicle is moving by using in-road wireless charging units, something that USU has been working on for a while.
Every prior attempt to electrify the car has assumed the vehicle would be the energy carrier. By comparison, the grid is much more efficient at moving energy from point A to point B, so if you can make dynamic charging safe and affordable, you are truly introducing something new.
For now, USU is focusing on stationary wireless charging and will launch an electric bus route later this summer in Salt Lake City at the University of Utah campus. The electric bus will travel along a mile-and-a-half route, stopping at either end for a few minutes to charge up. Using a bus at this stage makes sense as a way to test the technology because it's big, it travels along a fixed route and there is recharge time built into the schedule. An electric bus also helps reduce noise and emissions on campus, which is something the university wanted. USU's wireless charging team is also working on improving the space tolerance (making the charger work even if things are not perfectly aligned), the power levels (systems that are 20-50 kW instead of just 5-10 kW) and efficiencies.
Most people believe that in-motion charging is inevitable.
Muhs said the general industry-wide timeline for wireless charging is to have prototypes out over the next 12-18 months. To move beyond that, one of the requirements for wider adoption of wireless charging is interoperability. The reason this is important is that, in two or three years, when more wireless-charging vehicles are driving about, it will be important to allow a manufacturer's in-car pad to work when it's parked on anyone's in-ground pad. "This is a little different than plug-in technology in that, in the case of plug-ins, you can just buy an adapter from one person's plug to another cord, so to speak," Muhs said. "With wireless, you can't really do that. You can't slide something different underneath a car. So that means the whole standards setting process, particularly as it related to interoperability, is very important." Very important, indeed.
Another important angle is safety. USU's system will be able to detect if someone throws something metal onto the pad – a vital trait because some metals that get caught between the pads could heat up and catch fire – or if an animal wanders onto the pad. The magnetic field isn't dangerous to a cat walking through, but if it decides to curl up and take a nap there, it could spell trouble.
But wait. If all it takes is a random dime rolling onto the pad to stop charging, how reliable is wireless charging overall? Muhs said the current solution is to have the car – or a manufacturer's wireless charging app – notify your smart phone that charging has stopped so you can go and see what the problem is. In a parking garage environment, perhaps the attendant would be responsible for investigating charge disruptions? These sorts of things need to be worked out. "It's a great example of the devil is in the details," he said. "The need for additional development work, particularly around safety."
So, these are the issues with stationary charging. Dynamic charging is even more difficult. Still, Muhs said there are various companies working on in-motion charging, but very few will talk about it right now. The basic outline is to have coils in the road every so often, probably more (i.e., closer together) on uphills. Muhs said that 20 kW seems to be the average power requirement needed to move an EV, to the in-road coils would need to provide more than that to the passing cars. Think of it this way, if the pads only put out 20 kW, you would need to have them in a continuous line down the road. If the pads put out 100 kW, some power moves the car and the extra juice charges the battery. The allow the pads to be spaced out, which reduces the infrastructure that you need to install.
At 70 miles per hour, of course, a car will only be over a pad for a split second; a few milliseconds, in fact. In that time, the in-ground pad needs to be able to sense the car, broadcast power and then turn off again. "It is a challenge," Muhs admitted, but added that all of the technologies involved are advancing to the point where, "most people believe that in-motion charging is inevitable."
There are people working on all of this aside from USU. There has been a small demonstration in Korea (pictured above) – Muhs called it "quasi in-motion" – and the DOE recently announced a funding opportunity call that hinted at some sort of static wireless charging in three years. "By putting that in the call, that suggests to me that they're thinking about it in the relatively near-term," he said. "Whenever they first started looking at wireless a couple of years ago, they were talking about beginning research in 2016-2017. That's already been shrunk to 2012. I'd hate to make too strong a stab at this, but I'd say within three to five years. And there may already be some of that going on that we just don't see."