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Chevy Volt Fuel Cell Drive - Close Up View

Close up view of early engineering illustration of the hydrogen fuel cell version of Chevy Volt E-Flex electric car. Powered by a Fifth Generation GM fuel cell stack the same size as a four-cylinder gasoline engine, the 70kW (94hp) electric power plant produces the same output as the Fourth Generation version found in the fuel cell Chevy Equinox but is half its size.

Chevy's Future Fuel Cell Volt

MP3 Audio from second press briefing on General Motor's Volt electric car program, March 29, 2007.

By Bill Moore

Publisher's note: although this conference call was held on March 29, 2007, GM embargoed the media from publishing any reports on it until April 19, 2007.

Dr. Larry Burns began the second press briefing [GM battery briefing] by enumerating all the reasons why General Motors is focusing billions of precious research dollars on electric-drive vehicles, both hybrid, plug-in and hydrogen fuel cell.

He pointed to the on-going 'war on terror', the 2003 power blackout in the American northeast, the hurricanes of 2005, the leaks in the Alaska oil pipeline, the ongoing tensions with Venezuela, the growing public acceptance of the reality of global warming, the roaring economies of China and India, and oil price volatility: all equating to a serious energy security problem, one that will have a detrimental impact on an auto industry whose products are 98 percent dependent on petroleum.

He reminded the journalists present in Detroit and those listening in on the conference call, that 60 percent of America's fuel is now imported and China is now importing 45 percent of the petroleum it uses. Between now and 2030, half of the growth in energy demand will come from China and India.

"It's a matter of business", he said that GM find ways to displace oil and energy diversity is how it plans to do this, including building vehicles that use ethanol, electricity and hydrogen. He stressed that "purely electric" vehicles "will be a big part" of this strategy: vehicles that are electrically-driven where the source of their electricity may come from batteries, onboard internal combustion generators and hydrogen fuel cells.

Burns explained that the Chevy Volt concept car, which GM debuted in January at the Detroit Auto Show, is the model for what he called a "plug & play" approach that enables GM engineers to make use of a common electric-drive system on which they can mix and match energy sources: liquid fuel, battery, hydrogen. He pointed out the commonalities between the IC engine-generator version of the Volt and the fuel cell variant, as well as their differences.

The fuel cell stack and balance of plant (BOP) controls sit in the same location as the IC engine-generator version. The lithium ion battery (16kW in IC, 8kW in fuel cell variant) occupies the same tunnel between the passenger seats. The 4 liter, 10,000 psi hydrogen storage tank replaces the liquid fuel tank. However, unlike the IC model, the fuel cell model will make use of 3rd generation electric wheel motors instead of a central e-motor like that depicted in the illustration above.

Where the IC-variant will have a projected 40-miles of electric-only range before the engine-generator spins up, the fuel cell Volt instead will be able to operate 20 miles in battery-only mode after having been recharged overnight like the IC model using less-expensive grid power. Burns observed that the hydrogen Volt is currently designed to be a fuel cell-based plug-in hybrid, essentially making it an all-electric car with some of its energy stored in batteries and some in its hydrogen tank, while its sibling is a range-extended EV; an admittedly subtle distinction. It's smaller lithium battery pack is mainly intended to provide transient power assist for the fuel cell, as well as capturing regenerative braking energy.

Dr. Burns emphasized that GM sees this as the logical pathway to a hydrogen and electric future, where electricity and hydrogen are interchangeable energy carriers for power created from a diversity of fuel: coal, nuclear, hydroelectric and renewables. Interestingly, an engineering executive with GM's biggest competitor made this same observation privately to EV World just two days earlier.



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