Fuel Cells

                                                              Fuel Cells

A fuel cell is basically a battery and it works in the same way as illustrated in the below flash

animation.It uses a fuel, most often hydrogen, as the electrolyte. An advantage they have over

batteries is that they do not run down.They also produce no pollutants, but will produce

water as a by-product, as well as heat.

In order to produce power, the fuel in a fuel cell has to be supplied continually. Two fuels are

needed, and the most common are hydrogen and oxygen, or air may be used. There are also

two electrodes and two screens. An electrolyte such as potassium hydroxide will fill in the gap

between the screens. The different gases are put into the fuel cell at each electrode, one

positive and one negative. This causes a chemical reaction and a direct-current voltage

is produced.

At the anode in the fuel cell, the hydrogen atoms are stripped of their electrons, leaving

only the protons. A polymer membrane separates the two electrodes, and the electrons

are then forced to ride an external circuit before they can reach the cathode. This flow of

electrons creates the electricity. In order to generate a sufficient amount of energy, a stack

of fuel cells is required. A strong reason to continue to develop fuel cell

technology is because a fuel cell is able to convert the fuel directly into electrical energy,

whereas an internal combustion engine must first convert the fuel into mechanical energy,

which can then convert it into electrical energy.

In order to make it even more efficient, various types of fuel cells are being developed.

Other types of fuel cells can also produce electricity. They use a wide variety of fuels,

such as a phosphoric acid fuel cells (PAFCs); a molten carbonate fuel cells (MCFCs) - which

operates at temperatures around 650 °C; a solid oxide fuel cells (SOFCs) - which operates at

temperatures between 800 and 1,000 °C: and more. In each fuel cell, there is a definite need

to be able to control and remove excess heat. The most practical way, which also increases

the efficiency, is to convert the heat into electricity as well. Some of these electrolytes

are liquid, but some are solids.

A powerful advantage of a fuel cell over conventional sources of power, such as coal or

gas power generation stations, is that they convert energy much more efficiently.

Naturally, when oxygen and hydrogen recombine inside, large amounts of heat and

pressure will be produced. This requires strong containers that can withstand both.