2. Scientific Concepts
• A fuel cell is a device that converts the
chemical energy of a fuel and an oxidant
into electricity.
• A fuel cell is much like a battery, but it
does not run down or require recharging.
• It will generate electricity as long as the
fuel and the oxidant are supplied.
3. Scientific Concepts (cont.)
• Fuel cells chemically combine the molecules of
a fuel and an oxidant.
• Fuel – hydrogen, oxidant – oxygen (air)
• The hydrogen passes over the anode, while the
oxygen passes over the cathode, which are
separated by electrolytes.
• This causes the molecules to split into individual
atoms.
• When the hydrogen atoms meet the oxide
atoms, they combine to create water molecules,
which then generate electricity and heat.
4. Calculations and Data
• Because hydrogen is not a readily
available source, fossil fuels are converted
into hydrogen by a process called fuel
reforming.
• The chemical formula for this reaction
(with CH4) is: CH4 + 2H2O => CO2 + 4H2
• In high temperature fuel cells, CO acts as
the fuel. CO + H2O => CO2 + H2
5. Reactions and Equations
• Anode Reaction:
2H2 => 4H+ + 4e-
• Cathode Reaction:
O2 + 4H+ + 4e- => 2H2O
• Overall Cell Reaction:
2H2 + O2 => 2H2O
• Electrical Power Produced:
Power (Watts) = Voltage (Volts) X Current
(Amps)
6.
7. Experiments and Testing
• In 1893, Friedrich Ostwald experimentally determined the
interconnected roles of the various components of the
fuel cell: electrodes, electrolyte, oxidizing and reducing
agents, anions, and cations.
• In the late 1930s, Sir Francis Bacon managed to figure
out how to put fuel cells into Royal Navy submarines.
• Safety Considerations:
– Hydrogen is very flammable, and the gas must not leave the
vicinity of the fuel cell.
– Hydrogen is highly reactive with metals, so stainless steel is the
best choice for fuel cells.
8. • Grove discovered that by arranging two platinum electrodes
with one end of each immersed in a container of sulfuric acid
and the other ends separately sealed in containers of oxygen
and hydrogen, a constant current would flow between the
electrodes. The sealed containers held water as well as the
gases, and he noted that the water level rose in both tubes as
the current flowed. By combining several sets of these
electrodes in a series curcuit, he created what he called a "gas
battery"- the first fuel cell.
9.
10. History of Fuel Cells
• 1800 – British scientists William Nicholson and
Anthony Carlisle had described the process of
using the energy source of electricity to
decompose water into hydrogen into water.
• 1838 – The first fuel cell was invented by Sir
William Grove
• 1950s – NASA began to research and figure out
how to use fuel cells to help supply electricity in
their space missions
• 1966 GM Electrovan was the first hydrogen fuel
cell vehicle.