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. 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.