Scientists Create Tiny Fuel Cell Pump

On the battlefield, keeping an army effective at fighting the enemy often requires what military planners call a set of B's: bullets, beans and bandages.

But more than just ammunition, food, and medical supplies, there's another "B" that modern soldiers on the front lines need plenty of: batteries.

High-tech handheld electronic devices — laser range finders, global positioning systems, encrypted radios, and night-vision goggles, to name a few — have given the U.S. troops in Iraq a clear advantage. But providing enough batteries to keep those war-fighting tools humming along has been quite a challenge for the military's logistics.

That is why for years, the Defense Advanced Research Projects Agency has been funding researching into developing new portable power sources that could hopefully replace the need for batteries altogether.

Researchers at the Pacific Northwest National Laboratory in Richland, Wash., think they have developed a key component that could help the military shed its dependency on chemical batteries.

With funding from DARPA, the scientists at the lab have been working with other researchers to make miniature fuel cells a more viable option for soldiers who need electrical power for their portable devices.

Although hydrogen-based fuel cell technology has been well-known and used for larger applications — such as to power cars and spacecraft — getting such cells into miniature electrical devices safely has been difficult, since pure hydrogen is explosive.

"No one wants to walk around with a tank of hydrogen in their hand," said Jamie Holladay, a senior research engineer at PNNL. Instead, PNNL has developed a so-called reformer that will produce the explosive hydrogen gas from other fuels as needed by the fuel cell.

Tiny Refinery

Holladay says PNNL's reformer works by pumping methanol and water into microscopic channels that measure no larger than three strands of human hair.

The liquids interact with a "proprietary catalyst" and are "vaporized" by applying heat of about 250 to 300 degrees Celsius. The chemical reaction produces hydrogen and carbon-dioxide gases. The hydrogen can be used by the fuel cell to produce electricity while the waste carbon-dioxide gas is discarded.

Like other reformers, PNNL's device will make fuel cells more convenient to use. But because the device is no larger than a dime, it will help develop much smaller fuel cells that can be used in portable devices.

In development tests with researchers at Case Western Reserve University in Cleveland, PNNL's device was incorporated into fuel cells about the size of a common cigarette lighter. Such devices have been able to produce as much electrical energy as batteries that weight three times as much.

Holladay admits that for now, that's still not small or powerful enough for the military's requirements. Among the many obstacles Holladay and other researchers have to work out is producing a complete system.

It's a challenge of getting all the peripherals — the pumps, the packaging — worked out," said Holladay. "We're investigating how to put all those things together."