Student Zone: Fuel Cell

Watch GM's animated version of how
fuel cells work here!

Learn more about Fuel Cells at GM's
GMAbility Web Site

A fuel cell is a device that uses electrochemical energy conversion. It uses hydrogen and oxygen, and it makes useable electricity. In this case, the energy is used to power an electric motor in a car. A fuel cell is made up of three basic parts: the anode, the cathode, and the membrane in between them.

The anode is the negative side of the fuel cell. This is the side where the fuel is pumped through. In this case, that fuel is pure hydrogen. The grooves in the anode wall distribute the hydrogen evenly, so it can produce the most energy.

The membrane separates the two sides of the fuel cell and keeps the gases apart. The membrane is an electrolyte, which means it blocks electrons from passing through it. We'll cover more about electrons in the next section...

The cathode is the positive side of the fuel cell. Oxygen gets pumped through the grooves in the cathode. This is the side of the fuel cell that gets rid of the waste water that's produced.

You can think of the fuel cell as a small room with a big screen through the middle of it. Some things can fit through the screen and others can't. In the fuel cell, those things are hydrogen ions and electrons. That's what creates the energy for our car's motor.

Inside the fuel cell

Inside the fuel cell, hydrogen molecules are pumped through the anode. The membrane is coated so only positively charged ions can pass through it. This means the electron of the hydrogen molecule is stripped off and shot out the bottom of the fuel cell. The energy of the electrons coming and going is what creates useable electricity

The cathode, along with the oxygen molecules, attracts the missing electrons back so they can rejoin the hydrogen ions, once again making a whole molecule. In the right amounts, the hydrogen and oxygen fuse to form a water molecule (H2O).

Pure water and oxygen are the only emissions that a fuel cell produces. Unlike modern engines that burn fossil fuels, vehicles powered by fuel cells would likely produce little or no harmful emissions. There's a problem though. Each fuel cell produces only a fraction of the energy needed to run a motor.

Stack

Each fuel cell only produces a bit of the energy it takes to power a motor. To produce a useable amount of energy, a bunch of fuel cells must be strung together. This big stack of fuel cells is, not surprisingly, called a fuel cell stack.

The combined energy of the fuel cells is more than enough to power a car or truck. Also, fuel cells don't get too hot, even in a stack. All it would take to power our vehicle is a fuel cell stack about the size of a suitcase.

Vehicles

Fuel cells can be used to power many different kinds of vehicles. Cars, vans, trucks, SUVs, and even buses can be powered cleanly and efficiently by fuel cells. Whichever vehicle they're in, fuel cells need to work together with other components to put that vehicle in motion.

The fuel cell stack is only part of the whole system. The fuel tank, electric motor, and battery pack are the other crucial parts of that system. Without them, your cool fuel cell vehicle isn't going anywhere! Point to the different components to see what role they play in making our vehicle go.

So when are these vehicles going to be available? General Motors wants to make them as soon as possible! GM has already spent hundreds of millions of dollars to develop fuel cell cars and trucks and expects to produce fuel cell vehicles by the end of the decade.

So, that's about it! Fuel cells are pretty complex, but now you know what they are and how they work. Maybe someday, you'll be driving a clean, quiet, non-polluting vehicle powered by fuel cells. There's many things you can do to help the environment. Fuel cell vehicles are just one way you can make a difference!

Watch GM's animated version of how fuel cells work here!

Learn more about Fuel Cells at GM's GMAbility Web Site