Figure 7. Hydrocar H2 - O2
Storage Tanks.
electrolyzing water into hydrogen
and oxygen. After you’ve set up the
BS2 or 28X2 circuits (don’t connect
the battery or solar panel yet), fill
each of the two cylinders with
distilled water up to the 10 ml line
(Figure 7). Also, raise the car’s
wheels so they don’t touch the floor
or table, and purge any residual
hydrogen in the system as it will
affect the results. Notice that we are
not connecting the reversible fuel cell
to the car’s motor at any point in this
experiment. This is because the
motor presents a variable resistance
to the fuel cell as it spins, and I want
to avoid this for now; we’ll get to this
in a future article.
With the REEL Power software
running on your Windows PC,
attach the three volt battery or solar
panel to the circuit and witness a
plot similar to Figure 8. If you use a
solar panel, it will take much longer
to electrolyze the water as the solar
panel can’t deliver the same level
of current. (Of course, you’re free
to do so if you wish.) As you can
see, electrolysis starts with nearly a
A Little Fuel Cell History
The first known fuel cell can trace its roots back
to the 1830s when a Welsh born, Oxford educated
barrister named Sir William Robert Grove
(1811–1896) who practiced patent law and also
studied chemistry (or “natural science” as it was
known at the time,) realized that if electrolysis —
using electricity — could split water into hydrogen
and oxygen, then the opposite should also be true.
That is, combining hydrogen and oxygen with the
correct method would produce electricity. Sir
William was right and the first fuel cell was born. It
never went much beyond the laboratory stage for
over a hundred years, however.
Fast-forwarding to the early 1960s, a new
government agency
was about to undertake the next step in
maturing fuel cell technology. NASA was
developing mission-critical systems for the first
prolonged manned flight into space; once in
space, the orbiter needed a source of electricity.
Batteries were ruled out due to their size,
weight, and toxicity necessary to support a
mission of eight days in space. Solar panels
were also not practical at the time due to their
size, weight, and low energy output (about 4%
efficiency). The once obscure fuel cell thus
became the technological solution to NASA’s
dilemma of how to provide reliable “always on”
power for extended missions into space. The
PEM fuel cell was invented in the early
1960s by two General Electric scientists
and was used in the Gemini series of
spacecraft. It was replaced by alkaline fuel
cells for the Apollo program, as well as the
Space Shuttle. On the early missions —
especially Apollo 13 — there were
problems with fuel cells, but on subsequent
missions fuel cells became increasingly
more reliable.
Image Credits - Wikipedia
short-circuit as the reversible fuel
cell begins to split water into
hydrogen and oxygen. The internal
resistance of the PEM begins to rise
rapidly allowing a higher voltage and
more current from the battery or
solar panel to flow into the device.
Figure 9 shows the stabilization of
the Electrolysis Mode as the
electrolyzing voltage, current, and
power level off.
Figure 8.
Start of
Electrolysis
Mode.
Figure 9.
Electrolysis
Mode
Stabilization.
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May 2010