What is a Fuel Cell and How Does It Work ?


Fuel cells are electrochemical devices that convert a fuel's chemical energy directly to electrical energy with high efficiency. They began being used in space craft supplying the electricity, heat and water essential for astronauts in space. Fuel cells are as essential as ever in space travel today as they were in the beginning of space travel; the one big difference is that they last a whole lot longer and are much cheaper than they were. In fact these fundamental issues of cost, longevity and high efficiency are responsible for the hydrogen fuel cell being integrated into light vehicles. Significant progress has been made with hydrogen fuel cell electric cars, as the world auto makers are commercially releasing their cars in year 2015, with Hyundai now producing 1,000 cars for commercial release in year 2013.The hydrogen fuel cell is only one type of fuel cell and of course runs on hydrogen gas.

With no internal moving parts, fuel cells operate similar to batteries. An important difference is that batteries store energy, while fuel cells can produce electricity continuously as long as fuel and air are supplied.Fuel cells electrochemically combine a fuel (typically hydrogen) and an oxidant without burning, thereby dispensing with the inefficiencies and pollution of traditional energy conversion systems.

Fuel cells forego the traditional fuel-to-electricity production route common in modern power production, which consists of heat extraction from fuel, conversion of heat to mechanical energy and, finally, transformation of mechanical energy into electrical energy. In a sense, our bodies operate like fuel cells because we oxidize hydrocarbon compounds in our food and release chemical energy without combustion.

Fuel cells function on the principal of electrolytic charge exchange between a positively charged anode plate and a negatively charged cathode plate. When hydrogen is used as the basic fuel, "reverse hydrolysis" occurs, yielding only water and heat as byproducts while converting chemical energy into electricity, as shown in Figure 1. Pollutant emissions are practically zero.

Figure 1. Conceptual Operation of a Fuel Cell.

Basic fuel cell science

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