Gasoline Fuel Cells

Hybrid automobiles, like the Toyota Prius, that use both batteries and a gasoline engine for motive power have been  around for a while now; more recently,  “all electric” vehicles, like the Chevrolet Volt, have been introduced.   Though these new electric cars use electricity for motive power, they still have a small conventional engine so that their batteries can be charged if there is no charging station nearby.

The Technology Review reports that a group of researchers at the  University of Maryland have developed a new fuel cell technology that might someday replace the back-up engine.  Their approach uses a solid oxide fuel cell that can run on gasoline.

Now researchers at the University of Maryland have made a fuel cell that could provide a far more efficient alternative to a gasoline generator. Like all fuel cells, it generates electricity through a chemical reaction, rather than by burning fuel, and can be twice as efficient at generating electricity as a generator that uses combustion.

Burning fuel is, of course, a chemical reaction, too, but fuel cells do turn more of the fuel’s chemical energy into useable power.

Fuel cells of this type, which use a ceramic electrolyte, have been used for stationary power applications, but have not been considered practical for vehicle use, because of their considerable weight and high operating temperatures (~900 C).  The new design uses a newly-developed electrolyte material, can operate at lower temperatures, and can produce about ten times as much power per unit volume.  The research team estimates that a fuel cell stack 10 cm on a side would be sufficient to power a car.  At present, the cells operate at 650 C, but the team has plans to bring the operating temperature down to about 350 C,  meaning that cheaper and lighter materials could be used.  The lower operating temperature also means that the cell can be started more quickly (it has to be heated to its operating temperature before power can be produced).

In addition to general vehicle use, there is specific potential for this kind of fuel cell technology in long-haul trucks with sleeper cabs.  Currently, these trucks must have the engine idling to produce power for air conditioning and other appliances in the cab.  Producing electricity more efficiently, using fuel cells, could significantly reduce total fuel consumption.