New thin-film fuel cell packs powerful boost for consumer electronics
The LLNL Center for Microtechnology Engineering has developed and demonstrated
a laboratory prototype miniature thin-film fuel cell power source, which
provides portable electrical power for a range of consumer electronics.
With the LLNL fuel cell, a typical cell phone battery could be projected
to last more than 300 percent longer, extending standby time from four
days to two weeks, and talk time from six hours to two days.
The miniature fuel cell technology incorporates a thin-film fuel cell
and microfluidic fuel-processing components integrated into a common package.
Using easy-to-store liquid fuels, such as methanol, the fuel cell power
module provides greater than three times longer operating time than present
rechargeable batteries.
"LLNL’s fuel cell can be cheaper, smaller, with more energy
capacity than any battery or alternative fuel cell technology," said
Jeff Morse, principle investigator on the fuel cell project.
"Additionally, the higher energy capacity of such a product will
lead to further new classes of personal electronics," Morse explained,
"such as autonomous sensors and communication devices that are not
currently possible with existing battery technologies. This will facilitate
the integration of voice, data and computing technologies that cannot
be achieved with today’s technologies."
The patented design and method for making thin-film fuel cells combines
microcircuit processes, microfluidic components, and micro-electrical-mechanical
systems (MEMS) technology. This solution provides the consumer a lighter-weight,
longer-lasting power source for replacement of existing rechargeable batteries.
Morse predicts the MEMS-based fuel-cell power source will replace rechargeable
batteries, such as lithium-ion and lithium-ion polymer, in a range of
consumer electronics, including cell phones, handheld computers and laptops.
The MEMS fuel cell is designed to be 50 percent of the cost with 30 percent
of the weight, size or volume of existing rechargeable portable power
sources.
"The MEMS-based fuel cell has been designed to compete with existing
re-chargeable batteries in their respective marketplaces," said Morse.
Current estimates suggest a price of $1.50-$3 per watt-hour.
LLNL’s miniature fuel cell product incorporates integrated microfluidic
fuel distribution architecture within a miniature fuel cell package. This
feature enables the fuel cell to operate from highly concentrated methyl
alcohol fuel mixtures supplied from a replaceable fuel cartridge.
The impact to the consumer will be greater than three times longer periods
between recharging for initial products, with foreseeable improvements
of up to 15 times longer. Furthermore, recharging is instantaneous by
simply plugging in a new fuel cartridge.
The heart of this miniature power source utilizes a thin layer of electrolyte
material sandwiched between electrode materials containing appropriately
proportioned catalyst materials. Microfluidic control elements distribute
methyl alcohol fuel mixtures through a silicon chip over one electrode
surface while air is simultaneously distributed over the other electrode.
Integrated resistive heaters allow heating of the electrolyte-electrode
layers, thereby increasing the conduction of catalytically generated protons
from the fuel supply across the electrolyte to the air breathing electrode,
where they combine with oxygen to generate electrical current. Optimization
of current output through control of the catalyst and electrode surface
area, and microfluidic fuel distribution, offer a miniature energy source
providing continuous power for greater than three times longer than existing
rechargeable batteries.
The miniature fuel cell power source will find applications in the complete
range of consumer electronics as a replacement for rechargeable batteries.
These include cell phones, personal digital assistants, laptops and other
portable electronics.
Other applications include military electronics and sensors for remote
and autonomous application in which extremely long lasting power is required.