Fuel Cell Basics

Since I work for the Automotive Fuel Cell Cooperation (AFCC) I typically end up explaining fuel cells often to various people, I’ve created this page as a repository to answer some common questions regarding how they work and why we’d want to use them.

If you remember your high school chemistry then you’ve got the necessary tools to understand the basic principles of fuel cells. I’ve found the easiest way to understand fuel cells is to compare them to a device most of us are already very familiar with, the battery. In a normal AA battery that everyone is used to there are 3 main components: the anode, the cathode and the electrolyte. The anode and cathode are made of two materials that have a natural tendency to react with each other, but they are separated by the electrolyte. The electrolyte only allows ions to pass but acts as an electrical insulator, preventing any electrodes from passing and any reaction from proceeding.

How a fuel cell works (copyright Ballard Power Systems)

However, once you complete an electric circuit to the anode and cathode the electrons can take that path and the reaction proceeds, producing electricity. As the reaction proceeds the anode is slowly dissolved as the ions are transported to the cathode. Unfortunately, once the anode dissolves the reaction ceases and your battery either has to be recharged (if possible) or discarded.

Fuel cells operate on many of the same principles as batteries, with one important distinction: the electrodes are inert and merely facilitate the reaction. The two reactants at the anode and cathode must be supplied or fuelled to the anode and cathode for the reaction to occur. This means fuel cells never have to be recharged, instead they are refuelled, which may sound like a small difference, but has enormous implications.