After all the recent Detroit show hype over GM’s Volt plug-in hybrid concept car, DaimlerChrysler has claimed to be the only manufacturer building and testing plug-in hybrid vehicles with lithium-ion battery technology in customer fleets.

Current battery technology stands between automakers and a decent range on a full charge, without the intervention of some sort of onboard charging device.

Saying that lithium-ion battery research will accelerate future hybrid development, DC said its current Dodge (Mercedes) Sprinter plug-in hybrid electric vehicle (PHEV) can drive up to 20 “real-world miles” on electric-only power and is an industry first combining PHEV with diesel for maximum fuel efficiency.

Around 20 of the vehicles will be placed with customers in the United States between now and the first quarter of 2008 as part of a test fleet programme – four already are in operation.

“DaimlerChrysler is the only auto manufacturer currently evaluating a variety of plug-in hybrid powertrain configurations under customer-operation conditions in real-world service,” the automaker claimed.

DC added that battery development is one of the keys to the success of hybrid and fuel cell transportation while lithium ion holds the greatest promise for battery technology. Some of the Sprinter PHEVs are equipped with lithium ion batteries which are about half the weight and have much greater storage capacities when compared to nickel-metal hydride batteries. The vehicles will yield technical information through real world driving conditions about lifetime, performance and cost of batteries.

“The future of plug-in hybrid technology rests on a number of improvements, the most significant being batteries,” said Andreas Truckenbrodt, executive director – DaimlerChrysler hybrid programmes. “The battery systems in the PHEV Sprinter continue to provide valuable data on the possibilities with lithium-ion technology.”

Plug-in technology lends itself to commercial applications in which the vehicle returns to base after each shift to be plugged into the power grid but also works well in urban traffic situations for daily commuters.

Based on Mercedes-Benz commercial vehicle technology, the Sprinter PHEV has the ability to drive up to 20 miles on electric-only power. It accomplishes this with a switch on the dashboard giving the operator the ability to manually switch between modes as needed, or automatically by the vehicle control system. Two different combustion engines are offered – diesel or petrol. The diesel version will yield the highest fuel economy benefit and is the first fleet test of a diesel plug-in hybrid system.