Fuel Cells

For centuries people have sought ways to power their energy needs. Burning fossil fuels, batteries, and nuclear reactions are just a few of the solutions that have been used, yet all of them have problems of waste disposal. Hydrogen fuel cells have been suggested as a clean way of providing energy. Your challenge is to create a fuel cell that generates the greatest amount of energy. You’ll need to "get gassed" with hydrogen to be successful.

Planning and Carrying Out Investigations

Fuel Cells Brochure

What is a fuel cell?

A fuel cell is a device that uses oxygen to convert chemical energy to electrical energy. The most common type of fuel cell uses hydrogen as its fuel. Fuel cells produce water and heat as byproducts, and generally have an efficiency of 40-60%. In comparison, modern gasoline car engines typically have an efficiency of 25-30%.

What is a catalyst?

A catalyst is something that speeds up a chemical reaction. In hydrogen fuel cells, the catalyst is made up of platinum nanoparticles that are coated onto a thin piece of paper. The platinum helps remove electrons from the hydrogen. These electrons can then go on to power whatever is hooked up to the fuel cell.

How does a fuel cell work?

A common type of fuel cell and the type that is most likely to be used to power cars in the future is the Polymer Exchange Membrane Fuel Cell, or PEMFC. Fuel cells have two sides: the anode side, which is negatively charged, and the cathode, which is positively charged. In the middle of the cell sandwiched between the anode and cathode is the Proton Exchange Membrane, or PEM. The PEM only allows positively charged ions to cross it, and blocks electrons. Hydrogen gas enters the cell from the anode side and hits the catalyst, which helps separate each hydrogen atom into an H+ ion and two elections. The H+ ion flows through the PEM and towards the cathode, where the oxygen gas atoms. The electrons flow across the circuit that they fuel cell is attached to, and meet up with the H+ ion and the oxygen on the cathode side, where they all join to make water.

What is a fuel cell stack?

Individual fuel cells only produce about 0.7 volts a piece. In order to increase the voltage produced, fuel cells can be stacked in series. This is similar to regular batteries, which are actually many different cells that are connected together.

What is the difference between a series and parallel fuel cell stack?

A series fuel stack will increase the voltage produced, but the current produced will be the same amount as one fuel cell produces. A parallel fuel stack will increase the current produced, but the voltage will remain the same.

What is the difference between voltage and current?

Voltage is the difference in charge between two points. Current is the rate at which charge moves past a given point.

Walkthrough

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