Fast 30-Minute EV Charging May Not Be DIY

Last Updated Jul 22, 2010 8:00 PM EDT

As I wrote in my two-part series on big-box electric charging, the stores might soon be offering "fast charging" (just 10 minutes to half an hour) in their parking lots. Best Buy is in the lead there. But for safety reasons the big boxes may have to employ the equivalent of gas station attendants to run those stations. Or maybe, in an altogether new development, the utilities will do it for them.

Rapid chargers are already in use for airport vehicles and forklifts, but those aren't typically accessed by the public. Bret Aker, CEO of Aker Wade (which has made more than 8,000 fast chargers for those applications), says fast charging times can eventually be reduced to 15 minutes, which is the point at which "consumers will abandon gasoline for electricity."

That may well be right, but it presupposes that fast charging cars is like pumping gas, and it's fundamentally different. Level 3 fast charging is not for sissies, since it involves injecting EVs with 480 volts (four times house current), and critics like EV infrastructure company Better Place say it's never going to be safe. But I'd say that is far from a foregone conclusion. It's early days for fast charging, and not much safety work has yet been done on it. But good questions are being raised, and they could mean hands off the charging wand for you and me.

Watson Collins, manager of business development at New England-based Northeast Utilities, points out that some fast DC chargers will have interlocks that prevent their heavy cords from being "energized" (ie, carrying current) until they're plugged in. He said the high voltage is not to be trifled with -- the load from just two fast charging stations is equivalent to that of a McDonald's restaurant, he said.

Coulomb Technologies, possibly the U.S. charging leader today, is developing a 480-volt fast charger for delivery later this year that certainly looks like a gas pump. It can recharge a car in 30 minutes. It you can just plug in yourself and then come back in 30 minutes (or later), it's pretty convenient, but an attendant is likely to add a level of complexity most EV advocates probably haven't considered.

Some of the skepticism about fast charging is based not on danger to consumers, but to the batteries themselves. Fast charging heats up battery packs rapidly, so to keep them from overheating and possibly shortening their lives, some external cooling (not currently seen on cars like the Nissan Leaf) might be necessary. But even that might not be enough to ensure long life. Greg Frenette, a Ford battery vehicle manager, says he's skeptical that "you can charge these batteries in two or three minutes and send them on their way."

Working with The EV Project, the best-known name in electrical safety, Underwriters Laboratory (a/k/a UL), is certifying standards for all three levels of EV charging, including Level 1 (110 house current) and Level 2 (the 220 volts you might have for an electric dryer).

According to Gary Savin, vice president and general manager of UL's power and controls business unit, "Prior to certifying it, we have to consider how the chargers are going to be used, and what kind of environment they'll operate in. Potentially, an attendant would be needed." Savin said there are "a whole host of concerns," including both consumer safety and battery life.

Chris Pauly, UL's smart grid integration manager, said that utilities might end up as the "gas station operators" in this scenario. "They could resell the electricity to other operators, or they could operate their own stations. That's already getting underway in Europe."

Indeed it is. The German RWE AG, the largest diversified utility in the world, recently announced that it is partnering with Daimler on its electric drive Smart car program. The RWE name is on 500 charging stations set up by the utility in Berlin. Utilities are seen more as electricity providers for the companies that make and install charging stations, but RWE is hands on. According to Juergen Grossman, RWE's CEO, "We are developing a comprehensive concept, including an individually tailored, intelligent and convenient charging structure at home, at the workplace and in public places."

Northeast Utilities' Collins, however, isn't quite buying the electric station concept. "I don't see us having stations like ExxonMobil, BP or Shell," he said. "That's a whole other business, and they sell a lot of things besides gas."

Praveen Mandal, president of Coulomb, said "we haven't heard anything yet" about 480-volt chargers needing attendants, though he conceded, "The higher voltage and current, the greater the safety concerns. With 480 volts, you need to feel comfortable plugging in during pouring rain." He said his company's charger, a joint project with Aker Wade, is among those not energized until a positive contact is made. He also said it will be released in late 2010 or early 2011.

According to Mandal, charging times will determine how the stations will be used. "At five to 10 minutes, you can talk about the gas station model," he said. "At half an hour, it's more like Starbucks -- you'll drink coffee while waiting for your car to be ready."

Even though the cars are almost upon us, the fundamental questions, such as who will control fast charging, are far from settled. Don't make any assumptions yet about how this new form of "pumping gas" will play out.


Photos: RWE AG, Coulomb