TOKYO - The cost of platinum and the amount of the precious metal required for mass-market volumes is one of the greatest barriers to the development of market-viable fuel cell cars, a senior Nissan Motor Co. engineer says.
"The most critical technical issue is how to reduce the cost of the stack itself," said Masashi Arita, general manager of Nissan's powertrain and environment-research lab, in a recent interview.
For a fuel cell's power output to be in the range of 70 to 75 kilowatts, or about 100 hp, which is roughly the standard for fuel cell cars, "We need 80 to 100 grams of platinum," he said.
For comparison, the amount of platinum used in a catalytic converter is less than 10 grams per car.
That's one reason the cost of a fuel cell capable of powering a car is more than $200,000, he said.
If power output could be maintained at the 70- to 75-watt level while slashing platinum usage by 75 percent, to about 20 grams, then, "We could begin introducing some fuel cell vehicles into the market," he said.
But that's just a first-stage goal.
"To achieve a realistic cost level in the future, the amount of platinum used should be reduced to one-tenth the present level at a minimum," Arita said.
At the spot closing price of about $660 an ounce on Thursday, Jan. 30, 100 grams (equal to 3.53 ounces) of platinum would cost $2,330.
But mass production would change that equation dramatically. The cost of other components typically drops when volumes rise because of economies of scale. But that's not true for a rare commodity such as platinum.
"In mass production, the cost of platinum will dramatically increase," Arita said. "From the standpoints of cost and resource conservation, it is not possible to use that amount of platinum in mass-production vehicles."
Indeed, last Thursday's price was platinum's highest in nearly 17 years, showing the market's response to President Bush's call for more research into fuel cell technology. Spot platinum traded as high as $673 an ounce before settling back, continuing a rally that has taken the white metal from below $450 an ounce last year.
Traders in New York said they expect the metal to trade in the range of $700 to $800 an ounce within 90 days.
The platinum is used in the electrocatalyst layer of a fuel cell. Fuel cells require between 0.4 and 0.5 milligrams of platinum alloy per square centimeter of that layer.
A fuel cell consists of four key elements.
First is the proton exchange membrane, generally made of a material known as Nafion, which goes by the technical name of perfluorosulphonic acid polymer. This acts as an electrolyte.
Second is the electrocatalyst layer, using a platinum alloy.
Third is a gas diffusion layer made of carbon cloth or paper.
Fourth is a bipolar plate, which acts as a separator.
As hydrogen and oxygen move through the fuel cell's layers, they recombine to form water, or more accurately, water vapor. A slight electrical charge is produced as well. The goal of fuel cells in vehicles is to produce enough of a charge to power the vehicle.
International Editor James R. Crate in Detroit contributed to this report