Argonne to lead DOE's effort to evaluate plug-in hybrid technology
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ARGONNE, Ill. (Dec. 1. 2006) — Argonne National Laboratory has been
designated by the U.S. Department of Energy's Office of FreedomCAR
and Vehicle Technologies as the lead national laboratory for the simulation,
validation and laboratory evaluation of plug-in hybrid electric vehicles and
the advanced technologies required for these vehicles.
Plug-in hybrid electric vehicle (PHEV) technology is part of the president’s
Advanced
Energy Initiative, which
emphasizes the development of technologies that can significantly reduce the
nation’s dependence on foreign oil.
A plug-in hybrid electric vehicle is similar to the hybrid electric
vehicles (HEVs) on the market today, but it has a larger battery that is charged
both by the vehicle's gasoline engine and from plugging into a standard 110
V electrical outlet for a few hours each day.
More information about
Argonne's PHEV research
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"PHEVs and HEVs both use battery-powered motors and gasoline-powered
engines to get high fuel efficiency, but PHEVs can further displace fuel usage
with off-board electrical energy charged at home," explained Don Hillebrand,
Director of Argonne's Center for Transportation Research.
The result is a vehicle that can achieve far greater gas mileage than today's
HEVs, said Larry Johnson, Director of Argonne's Transportation
Technology R&D Center. "Experts
estimate that a PHEV could get more than 100 miles per gallon while the vehicle
runs primarily on the battery — compared to the 30 to 55 miles per gallon
that most of today¹s
HEVs achieve — at a charging cost that¹s equivalent to roughly $1
a gallon. For PHEVs with extra large batteries and motors, commuters who drive
less than 20 miles a day can potentially drive exclusively with its electric
motor for their daily commute."
While PHEVs are a promising vehicle technology,
many broad energy and environmental considerations must be examined before
they become widely available. For example, while a PHEV might be less costly
for the consumer to drive than a gasoline-powered vehicle, it would draw power
from the electrical grid when charging.
"Whereas virtually all electricity in the United States comes from domestic
energy sources," Hillebrand said, "in some areas, much of that electricity
would be generated by coal-burning power generation plants. The energy costs
to extract and transport the coal, as well as the environmental considerations
associated with burning the coal, are all part of the overall cost of using
plug-in technology."
These issues decrease in importance as the amount of renewable energy in the
electricity mix increases. There is also the question of how used batteries
will be recycled, and how much that recycling will cost on a per-vehicle basis
once all transport, processing, and disposal costs are considered.
Significant technical barriers must also be overcome before PHEVs are available
at local car dealers. These include cost, battery size and performance, durability
and safety.
Cost
PHEVs require additional, expensive components. Very large, heavy, and costly
batteries are required to provide vehicle range. Also, power electronics need
to be made smaller, simpler and less expensive.
The U.S. Department of Energy has determined that to be commercially viable,
a hybrid technology vehicle must repay its extra upfront cost in the form of
fuel savings within three years of the initial purchase.
Battery size and performance
The goals for a PHEV battery are compact size, high energy, high storage capacity
and the ability to support both deep and shallow discharge/charge cycles. With
today's technology, a battery that's powerful and durable enough to power a
PHEV's electric motor takes up more space than many vehicle makers or consumers
are willing to sacrifice. In addition to the space occupied by the battery
itself, there is also space on top of and around the battery that for safety
reasons cannot be used for design.
"Fortunately," Hillebrand said, "as battery technology evolves,
these issues are likely to diminish."
Durability
"Chances are," Johnson said, "if you own any of today's high-tech
rechargeable-battery-powered devices, such as MP3 players, PDAs or cell phones,
you understand this problem firsthand. A battery small enough to meet the device's
form factor and power needs must be recharged frequently, and over time, it
loses its ability to take and hold a new charge."
Eventually, the battery will need to be replaced. In a car, however, consumers
would expect the battery to last the life of the vehicle.
Safety
Any battery can be unsafe when mishandled or subjected to trauma such as physical
blows, extremely high-temperatures or fire. Even though a vehicle is safe under
normal conditions, a great deal of testing is required to determine its safety
in a crash or fire. As new battery technologies are developed, they will require
extensive testing before they are deemed suitable for in-vehicle use. Emergency
responders must also learn how to safely handle new vehicle battery technologies
in a crash or fire.
To address these issues and others, the U.S. Department of Energy's FreedomCAR
and Vehicle Technologies Program is funding research in a variety of technical
areas specific to PHEVs, including:
- Hardware-in-the-loop analysis
- Modeling & simulation
- Research and development for critical components such as batteries,
motors and power electronics
- Component/subsystem testing and validation
- System and interface control development
- Vehicle testing and validation
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