Nuts and Volts - May 2010

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.