New ORNL system provides hybrid electric autos with power to spare

OAK RIDGE, Tenn., Feb. 4, 2010 — An advancement in hybrid electric vehicle technology is providing powerful benefits beyond transportation.

Researchers at the Department of Energy's Oak Ridge National Laboratory have designed, fabricated and demonstrated a PHEV traction drive power electronics system that provides significant mobile power generation and vehicle-to-grid support capabilities.

"The new technology eliminates the separate charging mechanism typically used in PHEVs, reducing both cost and volume under the hood," said Gui-Jia Su of ORNL's Power Electronics and Electric Machinery Research Center. "The PHEV's traction drive system is used to charge the battery, power the vehicle and enable its mobile energy source capabilities."

Providing more power than typical freestanding portable generators, the PHEV can be used in emergency situations such as power outages and roadside breakdowns or leisure occasions such as camping. Day-to-day, the PHEV can be used to power homes or businesses or supply power to the grid when power load is high, according to Su.

The charging system concept, which is market ready, could also be used to enhance the voltage stability of the grid by providing reactive power, Su said.

The Power Electronics and Electric Machinery Research Center is DOE's broad-based research center helping lead the nation's advancing shift from petroleum-powered to hybrid-electric and plug-in hybrid vehicles. The center's efforts directly support DOE's Vehicle Technologies Program and its goal to provide Americans with greater freedom of mobility and energy security while lowering costs and reducing impacts on the environment.

ORNL is managed by UT-Battelle for the U.S. Department of Energy Office of Science.

NOTE TO EDITORS: You may read other press releases from Oak Ridge National Laboratory or learn more about the lab at http://www.ornl.gov/news.Follow ORNL through Twitter, RSS, Photos and Video.

what is totally cost of any electric over time.. my guess is it will never pay for itself. Why is ORNL doing cars? we have a war going on why are they not focusing on our troops?

It varies greatly, and it all depends on the lifespan of the battery pack. GM is warrantying the Volt's pack for 10 years and 150k miles, so they seem pretty confident. From what I know of different chemistries, due to their cell choice and very low depth of discharge, that's probably a fair warranty (with lifespan being somewhat longer than the warranty period). I think Tesla is being too optimistic with seven years on their lifespan estimate, however.

Part of the point of vehicle-to-grid (V2G) is to provide owners with an additional revenue stream or discounted electricity. Power companies normally have to pay to install hardware specifically to do what a V2G car will do for free.

A little off subject but I have personal experience that lithium powered portable tools do not work in cold temperatures. The Volt is powered by lithium batteries. How has GM gotten around this or have they?
First off, a bit on batteries. Rarely is there an issue of a battery simply "not working". It's all about operating voltage. For example, put some AAs in a digital camera and use the camera until it runs out of power. Batteries are dead, right? Now put them in a flashlight. It'll still work. The camera has much stricter voltage requirements than the flashlight.

The same applies to batteries in electric cars and power tools. Lower temperatures lower the voltage. If it lowers it below the minimum voltage the inverter can handle, it's "dead". But that's not the only way a battery could be "dead". The charge monitoring software can also determine that you've run it out of capacity (below the minimum depth of discharge). A "dumb" charge monitor will just look at the voltage to determine that, and could be way off due to the temperature. So it's hard to say, for your power tools, whether it's just a cheap charge monitoring system or whether your power tools have high voltage requirements.

Even in freezing weather, it's very unlikely for the voltage to drop lower than the minimum of a good quality automotive inverter, and EVs tend to have very good charge monitoring hardware (they tend to have very good of all kinds of battery management hardware -- things that are too bulky or expensive to put in things like power tools, cell phones, or laptops). Now, as you use up capacity, the voltage will drop further -- but this is compensated for by the fact that as you use the car, the battery also heats up. Alternatives are also relatively simple. Resistive heaters can work at very low voltages without a hitch, so having your car heat its own pack to get the voltage back up is absolutely an option. Also, GM's Volt isn't a pure EV; it's a PHEV. It has gasoline onboard, as well as a generator. So long as it can start its generator, it can get heat that way (in fact, that's what they do, at least in part, for cabin heat; internal combustion engines give out several times more energy in heat than they do in work)

What options has GM taken? That's all proprietary right now. There definitely are solutions, but which ones (if any) GM is doing are up in the air. In a proper EV, the primary additional losses for sub-zero usage are to run the cabin heater. And a PHEV can get its cabin heat from the generator's waste heat.

We do have one datapoint to go on. Lutz mentioned that during Michigan's cold snap in December, the Volt that he uses as his daily driver only went 28 miles (instead of the usual ~40) on electricity. So that certainly suggests some impact, but not a huge impact, especially given how amazingly cold it was in Michigan at that point in time (dang global warming!).

Anyway, the future of EVs really all comes down to cost. Not just of batteries, but also of all of the EV-specialized motor/inverter/charger hardware which is really expensive right now because they don't mass produce it. There's not any rare materials in a LFP-powered EV with an AC drivetrain, but most of the components are currently high labor, high capital to make. While the purchase price will be higher for a long time, we're probably not far from the lease price of an PHEV plus the cost of electricity being less than the lease price of a gasoline car plus the cost of gasoline. So I expect to see the lease market pick up on it first, due to sticker shock.

Researchers at the Department of Energy's Oak Ridge National Laboratory have designed, fabricated and demonstrated a PHEV traction drive power electronics system that provides significant mobile power generation and vehicle-to-grid support capabilities...Providing more power than typical freestanding portable generators, the PHEV can be used in emergency situations such as power outages and roadside breakdowns or leisure occasions such as camping. Day-to-day, the PHEV can be used to power homes or businesses or supply power to the grid when power load is high, according to Su.

I'm still in the dark too. :') This is a fancy way of saying, a vehicle has an outlet and can serve as an auxiliary generator when the grid is unavailable.

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