Ultracapacitor Could Extend PHEV Battery Life, Range

AFS Trinity, which recently withdrew its hybrid cars from the 2008 Los Angeles Auto Show, says that its battery-and-ultracapacitor-based power source for plug in hybrid vehicle systems is six times as durable as lithium batteries. The company reports that its novel power source was tested by Mobile Power Solutions, which reports that the battery-ultracapacitor system has an apparent useful life of 150,000 miles, compared to 25,000 miles for lithium batteries alone.

Used in combination with lithium-ion batteries, AFS Trinity says that the power source can provide reliable power for plug-in hybrids for the entire life of the vehicle. Battery life for a PHEV is of concern, since little data exist to support the idea that standard Li-ion batteries will last for more than 25,000 miles. The durability of the battery is determined, in part, by the charging cycle. Since PHEVs have a much more aggressive charging cycle than conventional hybrids, avoiding expensive battery replacement will be key to large-scale consumer acceptance.

The addition of the ultracapacitor enables the battery to avoid excessive heating from resistance, which occurs when the batteries are placed under high current load. This condition would occur when the vehicle accelerates from a stop. In low-current situations, such as maintaining a cruising speed, the battery trickle charges the ultracapacitor and then draws the stored charge out when more current is needed, rather than tapping the battery for extra current.

AFS Trinity CEO Edward Furia also says that the ultra-capacitor enables PHEVs to achieve a 40-mile all-electric driving range. With this capacity, most drivers would never need to burn gasoline in daily driving.

Source: AFS Trinity