MIT 8-3 DISA - Fuel Cell Markets

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AS BATTLEFIELD ELECTRONIC EQUIPMENT INCREASES POWER DEMANDS, RESEARCHERS ARE EXPLORING FUEL CELL
HYBRIDS AND OTHER ALTERNATIVES TO CONVENTIONAL BATTERIES.
BY CHERYL GERBER
MIT CORRESPONDENT
For both military and civilian users, the restrictions of battery capacity and the inefficiency of power consumption have become major factors limiting the effective use of mobile electronic equipment. Recent progress on the
battery technology front promises to reduce those restrictions, with improved power products being readied for sale
this year.
A recent Army-sponsored study released by the National Research Council, for example, recommended the use
of new and hybrid energy systems to support the increasingly diverse needs of mobile warriors of the Future Force.
While Land Warrior will equip future soldiers with high-tech electronics to increase awareness of the combat environment through the use of helmets with visual displays, chemical and biological sensors, radios and portable computers, the devices are not energy-efficient and will need new power sources to operate efficiently, the report said.
Compared with the four-hour limits in the consumer market, one or more military batteries typically provide sufficient energy to power electronics for a 12-hour mission. Still, longer missions will require improved technologies
that offer enough power to support 72-hour operations.
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Protonex is developing a lighter-weight power
solution. (Protonex photo)
The Protonex family of products will provide up to
1,000 watts. (Protonex photo)
The Army report evaluated and prioritized options for supplying energy to various low- and high-power applications on
the battlefield. It covered disposable and
rechargeable batteries, fuel cells, small
engines and hybrid-energy systems such
as those combining a battery with a fuel
cell. Applications that require an average
of 100 watts of power include portable
battery rechargers, laser target designator
devices used to guide a rocket, missile or
bomb to its target, and individual cooling
systems for protective garments.
The report concluded that among all
possible energy sources, hybrid systems
combining fuel cells and batteries provide
the most versatile solutions because of
their ability to provide power over varying
levels of energy use.
FUEL CELL COMBINATIONS
Hybrid systems combining batteries
and fuel cells are now in development,
with products set for release in 2005.
Unlike the battery, which eventually
goes dead if not recharged, the fuel cell
never dies as long as there is a flow of fuel
from external cartridges into the cell. The
device converts hydrogen and oxygen into
water and produces electricity in the
The K-Charge provides a stationary power solution.
(Valence Technology Inc. photo)
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Valence provides an alternative to cobalt oxide-based
lithium ion batteries. (Valence Technology Inc. photo)
process.
Fuel cell power generators are lighter
than other power sources currently in
use. There are several types of fuel cells
based on different chemicals and electrolytes. One example is the proton
exchange membrane (PEM) fuel cell,
which can power cars, buses and, someday, a house.
In an effort to lighten the load on the
special operations warfighter as well as
individual soldiers on extended field missions, the Air Force Research Laboratory
awarded a $2.6 million contract this past
spring to Protonex and Millennium Cell to
further the development of a lighter,
innovative power solution.
The technology is built on Protonex’s
NGen Portable Power System, a power
source that combines a PEM fuel cell
power-generation system with a chemical
hydride hydrogen storage system. The
contract was awarded under the Dual-Use
Science and Technology program, which
promotes the development of dual-use
technologies with application both in the
military and commercial sectors.
Protonex, which has been working
with the military since 2000 to develop
long-duration power solutions for
portable applications, is in the process of
commercializing a family of products in
the power range of 10 watts to 500 watts.
A soldier on a three-day mission, for
instance, would need to carry close to 30
pounds of batteries to equal the power of
a Protonex portable fuel cell system.
Weighing less than 10 pounds with fuel,
the company’s fuel cell products also provide increased operating time and faster
refueling in the field.
Millennium Cell’s Hydrogen on
Demand (HOD) systems generate hydrogen from sodium borohydride, which is a
derivative of borax. Dissolved in water and
passed through a proprietary catalyst
chamber, the sodium borohydride releases
pure hydrogen on demand to power a fuel
cell. Sodium borohydride fuel solutions are
nonflammable, high in energy density and
easily distributed.
The Air Force Research contract
addresses the need to replace the BA 5590,
the lithium-sulfur dioxide battery used
extensively for military communications
and other needs. It will demonstrate the
use of the Protonex PEM fuel cell with Millennium Cell’s HOD fuel in an integrated,
30-watt HOD/PEM system.
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“The program will replace 13 BA 5590
batteries weighing approximately 30
pounds that are used for a three-day mission with the PEM fuel cell and six cartridges of our HOD fuel weighing 10
pounds,” said Rex Luzader, the Millennium
Cell vice president of government and military business development.
“Once expended, the cartridges of fuel
can be replaced by a full cartridge using
hot swapping, meaning the device never
has to stop even when replacing the old
with the new cartridge,” Luzader said.
“Given that the military measures the
energy delivered by a battery in terms of its
energy per unit of weight—and the current
BA 5590 battery metric is about 160 watt
hours per kilogram—our targeted prototype for the Air Force program will deliver
an energy density of 470 watt hours per
kilogram.”
Use of sodium borohydride delivers a
cost savings of approximately $700 per soldier in a 72-hour mission, according to
Millennium Cell executives.
The Army Research Lab, meanwhile, is
testing a fuel cell from MIT Micro, a subsidiary of Mechanical Technology, which is
the same size and shape as most military
batteries currently in use. The fuel cell is
based on methanol, a common alcohol
with a high energy density, which can
allow systems to be lightweight and provide enough power for longer mission
duration.
“It’s a fuel cell and battery, so under
high power demands, the battery can take
over for the fuel cell. At start-up, the battery initially gets the system running until
the fuel cell comes up to full power. So the
battery is used as a power boost and the
juice for the start-up while the fuel cell
recharges the battery,” said Charles
Walker, a research physical scientist at the
Army Research Lab.
SAFETY ISSUES
Safety is another important issue in
battery development. Most lithium-ion
rechargeable batteries use carbon as the
cathode and alternate layers of cobalt
oxide and lithium as the anode. The
exchange of lithium ions between the
cathode and anode recharges the battery.
But cobalt oxide is sensitive to heat
spikes under high processing demands.
Heat spikes or a short inside a cobalt or
metal-oxide battery can trigger thermal
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runaway, which, when caught on fire,
feeds itself with its own oxygen.
“If your notebook battery pack had a
thermal runaway event, you could throw
it to the bottom of a swimming pool and it
would still burn at 800 degrees Celsius.
Now imagine yourself sitting in a vehicle
that has 1,000 of those cobalt batteries
with thermal runaway events, and you’d
be sitting in the bottom of a crater,” said
Joe Lamoreux, the chief operating officer
of battery maker Valence Technology.
Valence provides an alternative to
cobalt oxide-based lithium-ion batteries
in its phosphate-based Saphion technology, which advocates say is safer, more
stable and lasts longer than current
metal-oxide battery technology. Phosphate is also less expensive than cobalt.
“We’ve done tests where we fire
rounds into a cobalt or metal-oxide battery and it bursts into flames, whereas
when we fire the same number of rounds
into a battery using Saphion technology,
there is no event,” said David St. Angelo,
Valence vice president of large-format
energy solutions.
Valence offers three levels of its
Saphion technology: the N-Charge, KCharge and U-Charge power systems. The
N-Charge is a small-format application
that provides 130 watt hours with two 65
watt-hour batteries clipped together.
What’s significant about the 65 watt-hour
number is the fact that it falls under the
96 watt-hour maximum for large notebooks set forth in transportation regulations limiting the size of a lithium ion
battery that can be shipped without being
classified as hazardous.
The N-Charge can provide up to 10
hours of run-time and can be used for
mobile devices such as notebook PCs, cell
phones, PDAs, digital cameras and
portable DVD players. However, it is an
external device that needs to be
recharged. The K-Charge, or kilowatt
charge, is a light, low-volume power solution for utility and communications applications and an alternative to traditional
lead/acid UPS and stationary power solutions.
This past spring, U.S. Special Operations Command selected the N-Charge
system as the power source for its survey
equipment. The command is one of several military organizations to implement
the N-Charge system, according to
Valence.
PALM POWER
The Defense Advanced Research Project Agency (DARPA) Palm Power Program will produce compact fuel cell and
thermal-to-electric energy conversion
technologies for individual soldiers or
small groups of soldiers. They will be used
for distributed power generation and
could also be used for co-generation (producing heat, hot water or cooling in addition to electricity). Portable units could
be carried by soldiers and replace larger
diesel generator sets that must be towed
on a trailer.
Direct methanol oxidation fuel cells
are intended to provide an instantly
rechargeable power source. A 60-watt unit
has already been developed, but the program will produce a completely packaged
20-watt direct methanol fuel cell that,
combined with battery, could yield a
hybrid power system with significantly
longer endurance than a system using
batteries alone.
If a 20-watt, 12-volt DC goal is
achieved, then scaling up to higher power
levels, such as 50 to 500 watts, should follow. While DARPA will not actually
develop the larger systems, the agency
will field test them under realistic military conditions to determine their merit.
Three mission scenarios will establish
goals for the program: three-hour, threeday and 10-day missions. Typical missions
for these categories are three-hour micro
air vehicle reconnaissance missions,
three-day land warrior missions and 10day special operations reconnaissance
missions.
“We plan to demonstrate prototypes in
the next 12 months,” said DARPA spokeswoman Jan Walker. “The prototype systems and underlying technology could
then be further developed by the military
services for their specific needs.”
DARPA is working with Ball Aerospace, Adaptive Materials, ITN Energy
Systems, SRI International and Altex
Technologies to develop these systems. O
Comments and letters to the editor about this
story are encouraged. Contact Editor Harrison
Donnelly at [email protected]
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