The Fuel Cell Principle
The fuel cell reverses the process of electrolysis which is known from school. In the process of electrolysis by applying electric power water is decomposed into the gaseous components “oxygen” and “hydrogen”.
The fuel cell takes exactly these two substances and converts them to water again. In theory the same amount of energy which has been used for the electrolysis is set free by this conversion. In practice insignificant losses are caused by different physical-chemical processes.
So to say electric power is stored in hydrogen. Therefore we have a gas at our disposal in which electric power can be stored and this gas is hydrogen. In fuel cells we get back the electric power stored in the hydrogen. Most fuel cells are operating with air, so there is no need to store oxygen.
There are different types of fuel cells which are distinguished by construction and mode of function. In the next chapters, fundamental modes of operation of different fuel cells are described.