A fuel cell is a cell which produces electric current directly from chemical reaction,which is almost similar to electric battery,but here the reactant should be continuosly replaced as long as the cell should produce electricty.A fuel cell consists of an electrolyte sandwiched between two electrodes. Oxygen passes over one electrode and hydrogen over the other, and they react electrochemically to generate electricity, water, and heat.

Fuel cell technology is the technology of future for all our electric energy requiremens.This holds the key for next generation power requirements for automobiles, which is currently depended on internal combustion engines using fossil fuels, The imporatnt of fuel cell remain in the fact that It depends on renewable energy sources,That means even, it is energy source of the future, where possibily our fossil fuel reserves are fully utilized.

It is an electrochemical device that convert the chemical energy of a fuel directly and efficiently into electricity and heat, hydrogen or a mixture of compounds containing hydrogen is most suited fuel for such cells.

The different types of fuel cells include Polymer Membrane Fuel Cell (PEM), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC), and Solid Oxide Fuel Cell (SOFC). PEM is a low-temperature fuel cell being developed for transportation and other portable applications. PAFC operates at 200 °C and is suited for stationary applications. High-temperature fuel cells such as MCFC and SOFC are also suitable for stationary applications and are more efficient than PAFCs.

Proton Exchange Membrane Fuel Cell(PEMFC) is a type of PEM cell where pure hydrogen flows over the anode.The Hydrogen atom diffuses into the electrolyte, which is a PEM, here the electrons and protons dissociates and protons are captured by the cathode due to the potential difference,while the electrons are forced to travel to an external circuit due the electrically insulating nauture of PEM. When the proton reaches cathode it reacts with pure Oxygen forming Water (H2O).Hydrogen can be supplied to a fuel cell directly or may be obtained from natural gas, methanol or petroleum using a fuel processor, which converts the hydrocarbons into hydrogen and carbon dioxide through a catalytic chemical reaction.The fuel cell uses gas diffusion electrodes.

Each cell produces about .86 volts, In order to create enough voltage multiple cells are stacked to create a battery.

Fuel cell Has the following design issues, Very high Cost cuurently it cost about 32USD per KW. The water formed should be removed at same rate at which it formed, If water is evaporated fast then it will distroy the electrodes or if it is evaporated slowly it will prevent reactants from reaching the electrodes.A steady ratio of fuels must be maintained.The fuel cell must maintain same temperature throughout the operation, temperature requirement is between -35 to +40 Celcius.

Ballad Power Systems of Canada and Dailmer-Benz of Germany are world leaders in the application of fuel cell technology for meeting transportation needs