Fuel Cell Primer

A fuel cell is an electrochemical energy conversion device that produces electricity from hydrogen. Hydrogen is an element and has the simplest atomic structure of all elements, 1 proton and 1 electron. Electricity is the flow of electrons.

A fuel cell can be two to three times more efficient than an internal combustion engine in converting fuel to power. A fuel cell produces electricity, water and heat using fuel and oxygen in the air. Water is the only emission when hydrogen is the fuel.

Fuel cells typically consist of two electrodes, the anode and cathode. Sandwiched between the electrodes is an electrolyte, usually a solid Proton Exchange Membrane (PEM) that is capable of conducting protons from the anode to the cathode. The anode side is enclosed by a fuel/water chamber while the cathode side is enclosed by a water/air chamber.

As hydrogen flows into the fuel cell on the anode side, a platinum catalyst on the anode facilitates the separation of the hydrogen gas into electrons and protons (hydrogen ions). The hydrogen ions pass from the anode through the PEM and with the help of another platinum catalyst, combine with oxygen and electrons on the cathode side, producing water. The electrons, which cannot pass through the PEM, flow from the anode to the cathode through an external circuit containing a motor or other electric load, which consumes the power generated by the cell.

Some heat is also produced but because there is no combustion taking place the heat is far less than that produced in an internal combustion engine.

In principle, a fuel cell operates like a battery. Unlike a battery, however, a fuel cell does not run down or require recharging. It will produce energy in the form of electricity and heat as long as fuel is supplied.

Although hydrogen is an excellent fuel, it has huge problems with respect to production, transportation and storage. It takes considerable energy and sophisticated equipment to produce hydrogen by electrolysis or from methanol, methane, propane or other petroleum products. Hydrogen is a gas and must be transported and stored under pressure. Most experts agree that it will be decades before sufficient infrastructure exists to allow the use of hydrogen as a fuel, yet hydrogen is what is needed in a fuel cell.

It is possible to extract or produce hydrogen at the fuel cell from various fuels by using a system called a fuel reformer that forms part of the fuel cell system. Fuel reformers are complex, expensive and substantially reduce the efficiency of the fuel cell because some of the power produced by the fuel cell is required to power the reformer. In addition, there are often undesirable byproducts from the reformer.

Direct Methanol Fuel Cells offer several advantages over hydrogen fuel cells.