|AFS Trinity is using a lower-cost type of li-ion battery in conjunction with ultracapacitors in its plug-in drivetrain. Click to enlarge.|
AFS Trinity has filed a new patent application addressing the architecture, power electronics and control strategy for the Extreme Hybrid (XH) plug-in it is developing in partnership with Ricardo. (Earlier post.)
The proposed XH system uses lithium-ion “energy batteries” in combination with ultracapacitors for the vehicle’s electric energy storage system. The energy batteries are lower in cost than li-ion batteries optimized for power delivery.
These lithium-ion energy batteries are expected to cost $200 to $300/kWh for this type of cell. They are different from the lithium-ion power batteries that are expected to be used by other hybrids and plug-in hybrids and that are now found in some power tools.
Such power batteries currently cost as much as $750/kWh and are not expected to go below $500/kWh in five years. We also expect that the lower cost lithium-ion batteries that the XH will use will out-perform any known nickel-metal hydride (NiMH) batteries as well.—Donald Bender, AFS Trinity Chief Technology Officer
The use of ultracapacitors in combination with lithium-ion batteries allows the batteries to be both charged and deep-discharged without overheating or becoming less reliable, according to AFS Trinity. Instead of the batteries delivering the short bursts of power needed for acceleration, the ultracapacitors do this work. The ultracaps also capture the regenerative braking energy. The ultracaps make possible the use of the lower-cost lithium-ion batteries that are optimized for energy delivery, not power delivery.
The company is designing the XH to have up to a 40-mile All-Electric Range and to support electric driving at freeway speeds. Once the all-electric range is exceeded, the Extreme Hybrid will operate like a charge-sustaining conventional hybrid by using its gasoline or diesel engine in combination with electric power.
Mileage savings obtained from driving conventional hybrids are not large enough to offset their higher purchase prices that are linked to their expensive battery packs. Battery cost becomes even more important for plug-in hybrids. By providing much higher mileage and using low-cost batteries, AFS Trinity expects its Extreme Hybrid drivetrain to make possible the first money-saving hybrid vehicles of any kind. Drivers should expect the Extreme Hybrid to pay for itself in five years or less depending on your driving habits and the future price of gasoline.—Edward Furia, AFS Trinity Power Corporation CEO
In August 2006 AFS Trinity signed a Memorandum of Understanding with Austin Energy, founding participant in Plug-in Partners, a consortium of U.S. municipalities and utilities, providing them the first opportunity to test 50 or more AFS Trinity XH demonstration vehicles. (Earlier post.)