About Fuel Cells

Fuel cells can best be described as energy converters which make it possible to efficiently convert hydrogen and other energy carriers into electricity and heat. In a fuel cell system, electricity is produced when hydrogen is broken down in a controlled manner and reacts with oxygen.

General

A fuel cell functions like a battery, but instead of being charged with electricity over a long period of time the fuel cell is tanked with fuel, typically hydrogen or methanol, which is then converted into electricity. Heat is also generated.

Thanks to their long expected useful lives and theoretically non-existent environmental impact, fuel cells constitute an interesting alternative to most existing energy converters. The technology can be used to produce electricity for local communities, industries and homes as well as vehicles and portable electronics.

The Technology behind Fuel Cells

There are several types of fuel cells. The most common is the proton exchange membrane (PEM). In a PEM hydrogen molecules are broken down into protons and electrons with the help of a catalyst. Protons migrate through the PEM membrane, and come into contact with oxygen molecules introduced on the other side of the membrane.

The electrons are driven by the voltage in an external circuit and are united with the protons and oxygen on the other side of the membrane to form water, which is the only byproduct. The heat generated in the fuel cell needs to be cooled away, and can be used for heating of vehicles or housing, if required.

A fuel cell is assembled by attaching catalyst-prepared carbon cloth, or electrodes, to both sides of the membrane to form a package called membrane electrode assembly (MEA), which is placed between two patterned flow plates. Because each PEM cell generates only 0.5 volts, a large number of cells is required to power a computer or electric engine. One such stack can consist of just a few cells for a cell phone, 10 to 20 cells for a computer or up to 800 cells to power an electric car engine.

Flow plates are one of the most critical components of a fuel cell, with several crucial technical requirements that need to be adapted to the MEA and the fuel cell’s operating conditions. The plates are therefore unique for each fuel cell construction, and need to be carefully tested and optimized.