Even with these advances, the fuel cell wouldn’t come on instantly, and turning it on and off with every short trip in the car would cause a lot of wear and tear, reducing its lifetime. Instead, it would be paired with a battery pack, as a combustion engine is in the Volt, Wachsman says. The fuel cell could then run more steadily, serving to keep the battery topped without providing bursts of acceleration.
The researchers achieved their result largely by modifying the solid electrolyte material at the core of a solid-oxide fuel cell. In fuel cells on the market, such as one made by Bloom Energy, the electrolyte has to be made thick enough to provide structural support. But the thickness of the electrolyte limits power generation. Over the last several years, researchers have been developing designs that don’t require the electrolyte to support the cell so they can make the electrolyte thinner and achieve high power output at lower temperatures. The University of Maryland researchers took this a step further by developing new multilayered electrolytes that increase the power output still more.
The work is part of a larger U.S. Department of Energy effort, over the past decade, to make solid-oxide fuel cells practical. The first fruits of that effort likely won’t be fuel cells in cars—so far, Wachsman has only made relatively small fuel cells, and significant engineering work remains to be done. The first applications of solid oxide fuels in vehicles may be on long-haul trucks with sleeper cabs.
Equipment suppliers such as Delphi and Cummins are developing fuel cells that can power the air conditioners, TVs, and microwaves inside the cabs, potentially cutting fuel consumption by 85 percent compared to idling the truck’s engine. The Delphi system also uses a design that allows for a thinner electrolyte, but it operates at higher temperatures than Wachsman’s fuel cell. The fuel cell could be turned on Monday, and left to run at low rates all week and still get the 85 percent reduction. Delphi has built a prototype and plans to demonstrate its system on a truck next year.