Figure 10. Stylized
Example of a
Fuel Cell Stack.
cell phone directly
or, at least, supply
power to charge
your cell phone’s
battery. MBI Micro
has one that may
be something
you’re after
(Figure 12). The
company’s
Mobion, 100%
methanol fed,
passive DMFC
technology has
been demonstrated in fully-functional
prototypes and concept models in
three primary product directions:
external cord-free rechargeable power
packs; attached fuel cell power sources;
and embedded micro fuel cell designs.
They (correctly) claim that your
lithium-ion battery loses its charge
capacity after a few years, so why
not replace it with a fuel cell instead.
However, who keeps their cell phone
much over two years these days, and
who wants to carry around a bottle
of methanol to recharge your cell
phone? (Try getting it past the TSA at
the airport and see what happens.)
Nevertheless, it looks like it can be
done and it’s a neat concept.
For mobile fuel cell stacks, Honda
has one for its FCX Clarity car that is as
functional and sleek as the car itself
Figure 11. Bloom Box Fuel Cell
Installation (photo credit Bloomenergy).
(Figure 13). For mobile applications,
fuel cell stacks and the fuel itself must
be designed for both performance
and safety in mind, and Honda has
done both very well. Honda has
been the pioneer for many emerging
technologies like robotics (Azimo),
hybrid cars (the Insight), and now
fuel cell powered vehicles. Hopefully,
the Hydrogen Highway initiatives will
occur to make the FCX a reality.
important differences relative to the
fuel cell’s unique physical geometry and
fueling requirements. Depending on
the fuel cell type (Part 10) and power
requirements, each stack is different
but the idea is still the same: Take
something that generates about 0.5
volts at various currents (depending
mainly on physical size) and scale it
up to produce useful voltage, current,
and power — just like a battery pack or
solar module. Again, the similarities
between fuel cells and batteries are
amazingly close and, I guess, we can
throw in solar cells, as well.
Fuel cell stacks are used for
stationary, portable, and mobile
applications. As of this writing, the most
hyped of the stationary fuel cells is
the Bloom Box (Figure 11). The Bloom
Box is a solid oxide fuel cell stack
that purports to be the solution for
independent power for small homes
to large buildings and everything else
in between; it uses anything from
natural gas to bio gas for a fuel source.
Right now, it’s very expensive and
big and is only capable of powering
large facilities like the Google
headquarters and similar installations.
If it can be scaled down to a smaller
size, it may be able to power homes,
but this is yet to be realized even in
operational prototype form.
On the other end of the size and
power spectrum of fuel cell stacks,
you’ll find a few that can power your
Summary
This time, you learned more about
the essentials of how a fuel cell works
and what can be done with them in
terms of fuel cell stacks. You’ll need
this background information for our
next fuel cell article. In it, I’ll put our
fuel cell powered Hydrocar through
the paces to see how we can apply
most of what we’ve learned about
fuel cell technology to a neat mobile
fuel cell project. So until next time,
conserve energy and stay green. NV
Figure 13. Honda FCX Clarity Car
and Internal Fuel Cell Stack
Figure 12. Cell Phone Fuel Cell
( photo credit MTI Micro).
June 2010 51