› Introduction to How Fuel Cells Work
Photo courtesy Ballard Power Systems
A prototype fuel-cell car
You may have heard a lot recently about fuel cells. According to many news reports, we may soon be using the new energy-saving technology to generate electrical power for our homes and cars. The technology is extremely interesting to people in all walks of life because it offers a means of making power more efficiently and with less pollution. But how does it do this?
In this article, we'll take a quick look at each of the existing or emerging fuel-cell technologies. We'll detail how one of the most promising technologies works, and we'll discuss the potential applications of fuel cells.
What is a Fuel Cell?
If you want to be technical about it, a fuel cell is an electrochemical energy conversion device. A fuel cell converts the chemicals hydrogen and oxygen into water, and in the process it produces electricity.
The other electrochemical device that we are all familiar with is the battery. A battery has all of its chemicals stored inside, and it converts those chemicals into electricity too. This means that a battery eventually "goes dead" and you either throw it away or recharge it.
With a fuel cell, chemicals constantly flow into the cell so it never goes dead -- as long as there is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals.
The fuel cell will compete with many other types of energy conversion devices, including the gas turbine in your city's power plant, the gasoline engine in your car and the battery in your laptop. Combustion engines like the turbine and the gasoline engine burn fuels and use the pressure created by the expansion of the gases to do mechanical work. Batteries converted chemical energy back into electrical energy when needed. Fuel cells should do both tasks more efficiently.
A fuel cell provides a DC (direct current) voltage that can be used to power motors, lights or any number of electrical appliances.
There are several different types of fuel cells, each using a different chemistry. Fuel cells are usually classified by the type of electrolyte they use. Some types of fuel cells work well for use in stationary power generation plants. Others may be useful for small portable applications or for powering cars.
The proton exchange membrane fuel cell (PEMFC) is one of the most promising technologies. This is the type of fuel cell that will end up powering cars, buses and maybe even your house. Let's take a look at how they work...