Overcoming Remaining Technical Barriers

DOE is planning a new three-year development program to address the significant remaining technical barriers to achieving the viability of fuel cell technology in transportation. For the fuel cell power system, key areas include carbon monoxide (CO) poisoning, stack material cost/performance (bipolar plates, membrane electrode assemblies, carbon paper), thermal management, and integrating balance of plant (compressors, humidifiers, heat exchangers, sensors, and controls). For the fuel processor, key challenges include CO cleanup, system integration and efficiency, start-up/transient operation, and thermal management. Hydrogen storage and overall propulsion system integration and validation also require serious attention. Based on priorities and guidance provided by the auto industry, DOE is addressing these barriers by focusing its component development activities on the following:

CO cleanup devices and CO tolerant fuel cell catalysts;

• Lightweight, low-cost bipolar plates;

• Low-cost, high-volume manufacturing processes and materials for membranes and membrane electrode assemblies; and

• Balance of plant ancillary components such as compact heat exchangers, sensors, and controls.

BREAKING DOWN COST BARRIERS 120 The present cost of PEM fuel cell systems (projected to high volume production) needs 100 to be reduced to less than $50/kW to be competitive with internal combustion 3 80 engines. Figure 6 shows the year 2000 and S 60 ultimate (year 2004) cost targets for -s automotive applications established by the 0 40 DOE-industry program. Breaking down the cost barrier will require choosing appropriate 20 materials (with adequate performance) that are suitable for high volume manufacturing 0 processes. This will be accomplished through the component R&D activities (discussed above) in which both industry and Figure 6: Cost Targets for the DOE-Industiy Program the national laboratories will play key roles.

The expertise of the national laboratories with advanced materials and processing techniques will be critical to the success of these efforts.

Intelligent system trade-offs between performance, size, and cost will also be required to reduce the costs of the fuel cell power system and fuel processor. For example, initial efforts to increase fuel cell performance have led to the development of high efficiency compressors and expanders. However, this increased performance needs to be evaluated against the added size and cost of the compressor/expander to the total power system. Several developers are now pursuing low or ambient pressure operation of the stack as an option to resolving this trade-off. In the fuel processing area, the total system impact of choices for the type of CO cleanup (i.e., preferential oxidation, filters, etc.) has to be carefully evaluated because of the serious implications for performance, size, and cost.

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