Fuel cell technology has been used for a number of years in the space industry. Recent improvements in technology and the need to seek alternative fuel technologies for the automotive industry have seen a number of manufacturers develop fuel cell technology for use in automobiles. In a vehicle powered by a fuel cell, the electrical motor is powered by electricity generated by the fuel cell.
A fuel cell is an electro chemical device that combines hydrogen and oxygen to produce water and in the process it produces electricity and heat. Fuel cells operate without combustion so they are virtually pollution free.
Another electrochemical device you are already familiar with is the vehicle battery. In a battery all the chemicals are stored inside, and it converts those chemical into electricity. This means the battery eventually becomes discharged until you recharge it.
In a fuel cell, the chemicals oxygen and hydrogen constantly flow through the cell, like fuel through an engine, so it continues to produce electricity as long as fuel is available.
There are four basic elements to a fuel cell, the anode, the cathode, the electrolyte and the catalyst.
Pressurized hydrogen flows into the fuel cell anode. The platinum coating on the anode helps to separate the gas into protons (hydrogen ions) and electrons. The electrolyte in the center allows only the protons to pass through to the cathode side of the fuel cell. The electrons cannot pass through this electrolyte and flow through an external circuit in the form of electric current.
At the same time, oxygen flows into the fuel cell cathode where another platinum coating helps the oxygen, protons, and electrons combine to produce pure water and heat.
A fuel cell only produces a voltage of about 0.7 volts. To get the required voltage for automotive applications a fuel cell stack is created. The number of fuel cells in the stack determines the total voltage, and the surface area of the cells determines the total current.
Fuel cells use hydrogen and oxygen to produce electricity. The oxygen can come from the air, however hydrogen it is not readily available. Hydrogen is difficult to store and distribute. To address this problem in automotive applications, an additional device called a reformer is used.
The reformer turns hydrocarbon or alcohol fuels into hydrogen. So to make fuel cells practical for automotive applications car manufacturers are developing better fuel cell systems and technology to improve the efficiency of the system while using readily obtainable fuels.
