GM next generation and current fuel cell stacks - Click above for high-res image gallery
In spite of the cuts at General Motors over the past year, work has continued in the powertrain labs at the Warren, MI tech center on hydrogen fuel cells. Back in 2007, GM shifted much of its fuel cell work from the Honeoye Falls, NY research facility to the production engineering group in Warren. The result is the fifth-generation fuel cell stack shown above on the left. The unit on the right is the stack from the fuel cell Equinoxes that are running as part of Project Driveway in California, New York and Washington, DC. The new generation unit matches the 93 kW output of the Equinox unit but occupies the same volume as the 2.4-liter EcoTec four cylinder.
GM has engineered this new stack specifically with the aim of making it producable in volume at a much lower cost than previous designs. That means it gets a cast case with integrated cooling passages and other subsystems. One of the highest cost elements of a fuel cell stack is the platinum used as a catalyst. Read on after the jump.
Photos Copyright ©2009 Sam Abuelsamid / Weblogs, Inc.
The fourth-gen stack in the Equinox uses 80 g of platinum while the new stack uses just 30 g. This new stack is due for production in volumes of up to 10,000 units a year by the middle of the next decade. In the subsequent iteration, GM plans to have the platinum content down to under 10 g, which would put it on a par with current catalytic converters.
Other areas where the engineers have optimized the new stack are the subsystems like the hydrogen injector. They have gone from a massive unit about the size of a text book to a much smaller unit similar in size to a current fuel injector. Not only is the new unit smaller and lighter, it is much less expensive to make.
GM's Project Driveway field test has now been running for almost two years and there are about 116 Equinoxes on the road in the U.S. and Europe. The drivers operating these fuel cell crossovers have now accumulated almost a million miles and the engineers continue to optimize the control software. The result is that the durability of the stack has been significantly improved from the original 50,000 miles to over 80,000 miles. In addition, the range of the Equinox has climbed from the original 160 miles to over 200 miles. Between GM, Daimler, Toyota and Honda, there has been a lot of progress on automotive fuel cells. Now, if only they could do something about that pesky problem of finding hydrogen.