Fuel Cells In Cars

On October 20th Amo Laesecke from the National Institute of Standards and Tehcnology came and spoke to the Chemical Engineering undergraduates at one of our Friday Pizza Seminars. Mr. Laesecke talked to us about the use of fuel cells in cars. While Mr. Laesecke worked for Daimler Chrysler he researched using fuel cells as an alternative fuel source.

They’re out there.

    Fuel cells are already being used commercially and a little in transportation.  Phosphoric acid fuel cells are already being used in hospitals, nursing homes, hotels, office buildings, schools, utility power plants, and an airport terminal.  These cells can generate electricity at more than 40% efficiency and nearly 85% of steam this fuel cell produces is used for cogeneration. This can be compared to 30% efficiency for the most efficient internal combustion engine also operating temperatures are in the range of 400 degrees F.  These fuel cells also can be used in larger vehicles, such as buses and locomotives.  This could cut down on pollution because the only product is water.

 What is a full cell?

When you think of a fuel cell you can think of at as an everlasting battery as long as fuel is supplied.  A fuel cell consists of two electrodes sandwiched around an electrolyte.  Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat.  Hydrogen fuel is fed into the "anode" of the fuel cell.  The Oxygen, or air, enters the fuel cell through the cathode.  By the use of a catalyst, the hydrogen atom splits into a proton and an electron, which take different paths to the cathode.  The proton passes through the electrolyte and the electrons create a separate current that can be utilized before they return to the cathode.  When this process is complete the electron is reunited with the hydrogen and oxygen to form a molecule of water.  A fuel cell system which includes a "fuel reformer" can utilize the hydrogen from any hydrocarbon fuel.  This means that the fuel cell can be powered by natural gas, methanol, and gasoline.  This would be very helpful to people who drive these fuel celled powered cars because they can pull up to any gas station and fill up their tank.  Since the fuel cell relies on chemistry and not combustion, emissions from this type of a system would still be much smaller than emissions from the cleanest fuel combustion processes.

What do they use in cars?

            The Proton Exchange Membrane (PEM) fuel cell is the first and primary candidate for placing fuel cells in cars according to the U.S. Department of Energy.  These cells operate at relatively low temperatures (about 200 degrees F), have high power density and can vary their output quickly to meet shifts in power demand.  These cells are also suited for applications in automobiles where a quick startup is required.

A new type of fuel cell that is being developed is the direct methanol fuel cells (DMFC).  These cells are similar to the PEM cells in that they both use a polymer membrane as the electrolyte.  However, in the DMFC, the anode catalyst itself draws the hydrogen from the liquid methanol, eliminating the need for a fuel reformer.  Efficiencies of about 40% are expected with this type of fuel cell, which would typically operate at a temperature between 120-190 degrees F.  They have found that with higher temperatures higher efficiencies are achieved.  This would be very helpful in automobiles because the designers of the fuel cell would prefer the fuel in a liquid state.  It is much easer to handle and to store in the car.

Who is using this technology now?

    Three of the major car producers are putting this research into their cars.  The three companies in the U.S. are Daimler Chrysler, General Motors, and Ford.

Chrysler has unveiled a fuel cell concept vehicle based on the Jeep Commander. The engine is a fuel cell/battery hybrid designed to utilize gasoline as fuel.  The company plans to have a working methanol hybrid fuel cell system in the Commander by the summer of 2000.  This report was done in January of 1999.

General Motors unveiled the Precept concept car, in both hybrid and fuel cell powered forms.  The Precept has a four-wheel drive, dual-axle setup.  Electricity from the fuel cell is used to drive the electric motor on the Precept's front axle.  Composites of actual data indicate the fuel cell Precept will achieve 108 miles per gallon gas equivalent.  Officials say GM intends to have a "production ready" fuel cell vehicle by 2004.

Ford is allied with Ballard and Daimler-Benz in the development and marketing of fuel cell engines and electric drive trains.  They expect to deliver a working hydrogen fueled vehicle to the California Fuel Cell Partnership during 2000.  Ford unveiled the TH!NK FC5, a family size sedan powered by a Ballard fuel cell electric powertrain using methanol fuel.  Based on the 2000 Ford Focus, the TH!NK FC5's fuel cell powertrain is located beneath the vehicle floor, so it doesn't compromise passenger or cargo space.

For a movie of how a fuel cell works visit this site: 

 http://www.ballard.com/pem.htm

Brian Hopkins

Michael Fears