An article about a MEMS-based portable fuel cell for charging wireless electronic devices, presented as a plenary talk at SPIE Photonics West in January, is one of eight SPIE proceedings papers published in the current volume of the open-access journal SPIE Reviews.
Samuel B. Schaevitz, CTO and cofounder of Lilliputian Systems (USA), discusses his company’s development of a portable charger that uses a solid oxide fuel cell (SOFC) powered with butane in “Powering the wireless world with MEMS.” Lilliputian’s pocket-sized, battery-replacement device, which can power a cell phone for five to 10 times longer than existing batteries and can be instantly recharged by inserting a new, recyclable butane cartridge, can eliminate the need to plug in for recharging, Schaevitz says.
SPIE Reviews is an open-access virtual journal that includes review articles, tutorials, and plenaries on emerging and rapidly evolving optics and photonics technologies and their applications. The journal features selected reviews and tutorials published in SPIE’s seven topical journals as well as selected plenary papers from SPIE conferences.
Schaevitz argues in his paper that fuel-powered systems have a fundamental advantage over batteries because battery technology has improved by only 5% per year since 2001 while consumer demand has grown tenfold.
Using butane, “Lilliputian Systems has chosen the highest energy-density fuels, combined with the most efficient and dependable fuel cells” and MEMS fabrication methods to “provide high-efficiency and reliable operation in a very compact Silicon Power Cell™,” according to Schaevitz.
“Lilliputian leverages microfabrication techniques to solve the challenges of extreme insulation, high-temperature multi-chip sealing, severe thermal expansion stresses, compact electrical routing, and optimal distributions for the coupled flow, electrical, and chemical reactions,” he says. “This combination overcomes the barriers which have prevented other fuel-cell efforts from being [successfully] commercialized.”
Schematic of Lilliputian’s Generator Chip:
(1) Fuel is mixed with a small amount of air and fed into the fuel processor; (1b) Fuel breaks down into simpler fuels, hydrogen (H2) and carbon monoxide (CO), which are easier for the fuel cell to use; (2) Air is provided to the other side of the fuel cell; (3) Fuel and air react across the fuel cell membrane, producing electrical power at the terminals of the fuel cell; (4) Remaining fuel mixes with remaining air and is burned and cleaned in the catalytic converter; (5) Clean exhaust leaves the Generator Chip
Schaevitz lays out the reasons for the key technology choices:
- Solid oxide fuel cell for efficiency, simple construction, and robustness to environmental factors
- Butane fuel for safety and high energy density
- MEMS manufacturing for complex mechanical construction and compact size
Says Schaevitz: “Portable fuel cells can cut the final cord connecting consumer electronics users to the wall at a time when people are increasingly dependent on their amazing devices and increasingly frustrated by the frequent pull back to a non-mobile plug.”
Lilliputian Systems has since announced that it has signed an agreement with Brookstone to launch its “revolutionary portable charger for power-hungry consumer electronics” into the market under the Brookstone brand.