Fuel cells start to look real

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Honda FCX-V3
Honda Motor Co.'s latest entry in the automotive fuel-cell sweepstakes, the FCX-V3, combines some of the most advanced features of other experimental vehicles the automaker has built in the past. Honda's first foray into hydrogen fuel-cell technology, the FCX-V1, was displayed last year along with its methanol-powered cousin, the FCX-V2. Unlike the FCX-V2, which includes an onboard methanol reformer, the FCX-V3 combines key systems and components from Honda's alternative vehicle lineup. From the battery driven EV-Plus, the new car takes an electric drive and regenerative braking systems; from the CNG-fueled Civic GX, the high-pressure fuel storage tank; and from the gasoline/electric-powered Insight, the precision energy-management system. All systems and technologies were modified and/or improved for the new model.

Honda's FCX-V3.

In addition, the FCX-V3 is equipped with a specially made ultracapacitor, replacing the metal-hydride battery pack installed on the FCX-V1, and a 62-kW fuel-cell stack supplied by Ballard. FCX-V3 has a 60-kW synchronous motor having a mass of 34 kg (75 lb).

"We used an ultracapacitor - a charge-separation energy storage device in which no electrochemical change takes place during the charge/discharge cycle - to create a fuel-cell hybrid with the highest total system efficiency (40%)," explained Ben Knight, Vice President Honda R&D America Inc. "This unique approach gives the vehicle several advantages; the ultracapacitor's high rate of energy transfer allows regenerative braking as well as quicker driving response with improved feel and no time lag. The ultracapacitor permits the stack to operate at a lower load level and so at a higher efficiency. A full fuel-cell vehicle may lose a bit of regenerative braking energy and may give up some fast power response, and an electrochemical battery-assist requires the use of a high-current controller and adds some inefficiency when energy goes in and out of the battery."

Through miniaturization, repositioning, and elimination of components, Honda engineers have expanded interior space. The FCX-V3 seats four, two in the front and two in the rear. In reconfiguring the car's powertrain, Honda positioned the stack underneath the floor, extending from around the base of the front firewall to the middle of the rear seat. Designers put the ultracapacitor behind the stack also under the floor, extending to the center of the rear wheel well. The hydrogen storage tank is in the trunk. A substantially downsized power control unit (about 65% more compact) has been placed under the hood, while a 20% smaller drive motor is located adjacent to the front wheel.

Honda's FCX-V3.

The FCX-V3 also features a quicker startup time - 10 s compared to 10 min for the FCX-V1. In addition, it can be refueled faster - 5 min compared to 20 for the FCX-V1, which featured a metal-hydride hydrogen-storage system. The 98-L (26-gal) carbon-fiber-wrapped pressure cylinder operates at 25 MPa (3600 psi). Honda did not, however, expand the vehicle's range. The FCX-V3, like the FCX-V1, covers 180 km (112 mi) on a single tankful of hydrogen in stop-and-go city driving. The model, like its predecessor, achieves 130 km/h (81 mph).

Future targets include 30% annual cost reductions over the next few years; 5 to 10% lower mass by 2002 to 1645 kg (3630 lb); and a 200-km (125-mi) range, also by 2002. Long term, the company wants to achieve 320 to 400 km (200 to 250 mi), which is close to gasoline-fueled cars. Researchers also want to improve the car's cold-start capability while assuring safety in the event of an accident by storing hydrogen fuel in a metal hydride. Honda guarantees startup of the FCX-V3 at temperatures above 5°C (41°F). The decision to use a Ballard stack instead of its own - Honda used its own stack on the FCX-V1 - reflects the generally high esteem accorded the Canadian company's technology by Honda researchers. "Ballard is very advanced," declared one senior executive who added that Honda may use its own stack for the next generation model. "It just so happened that Ballard's stack was more advanced than ours this time around. Ours (the 60-kW unit adopted for the FCX-V1) is more than a year old." Knight said that Honda developed its own stack as a way to ensure it understands the fundamentals of the technology.

German chemicals group Celanese AG and Honda will jointly develop a new fuel cell for car engines. Celanese will provide Honda with solid polymer membranes, which would run with a Honda-produced mechanical component to form membrane electrode assemblies (MEA). "It is our intent to become the leading MEA supplier to the emerging fuel-cell industry. This agreement with Honda is crucial to our success in the automotive sector," Celanese Management Board Member Ernst Schadow said. The membrane, which is made from polybenzimadazol, a high-performance plastic made exclusively by the company, is capable of working at twice the temperature managed by rival materials. It has already been successfully tested, but it was not yet clear what kind of sales volume could be expected, or when.

While Honda's management does not expect fuel-cell vehicles to come into the mainstream for 10 to 20 years, the Japanese automaker remains committed to commercializing its first unit in 2003.

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