This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Direct Methanol Fuel Cells for Automotive Power Systems
Technical Paper
2000-01-0012
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
Direct fuel oxidization yields major fuel cell power system simplifications and potential performance advantages, particularly for an automotive power plant application. The system simplification is particularly striking when a direct fuel system is compared to an “indirect” fuel cell system in a vehicle (where the fuel on board must be “reformed” and “cleaned” to provide a hydrogen-rich gas “reformate” for use in the fuel cell system). The inherent complexity, the losses of efficiency, and the emissions associated with the fuel processor required for the indirect system combine to make the comparison to a direct fuel system extremely favorable toward the latter in all important aspects.
Although direct fuel oxidation is possible in principle for almost any hydrocarbon or alcohol fuel, at the present time the direct fuel cell system with the highest levels of system fuel efficiency and power density is the direct-hydrogen system. However, the use of hydrogen as a vehicle fuel (compressed, adsorbed, or liquefied), has one overwhelming disadvantage - the problem of effectively storing the hydrogen on-board the vehicle (added volume and weight, for example, which inhibit acceleration performance and efficiency, and intrude on passenger and payload space). These disadvantages largely negate the cell/stack advantage of a direct-hydrogen system.
In contrast, the major system simplifications and potential performance advantages of a direct fuel cell system are available, essentially without significant disadvantage, if the fuel cell system can directly use a high-energy-density liquid fuel (e.g.; an alcohol or hydrocarbon). The R&D and commercialization challenge is to develop a liquid-fueled direct fuel cell system for automotive applications which has adequate levels of fuel conversion efficiency and power density.
Within the existing technical limitations of the direct fuel cell state-of-the-art (especially the available catalysts and electrolytes), there is only one liquid fuel with sufficient reactivity to use directly in a fuel cell - that fuel is methanol (Methyl Alcohol, CH3OH, MeOH). The status and future potential for the Direct-Methanol Fuel Cell (DMFC) is an important consideration in evaluating the overall future commercial possibilities for all Fuel Cell Vehicle (FCV) designs, and for understanding the potential long-term - and transitional -- role of methanol as an FCV Fuel. The state-of-the-art for DMFCs is reviewed here, and the issue of operation in a load-following vs. a hybrid powersystem are evaluated, together with some indications of future improvements for the DMFC. A major consideration is that the conventional wisdom that a DMFC stack must be operated in a hybrid power system is based on a fundamental misinterpretation of the operating characteristics of the DMFC.
Recommended Content
Authors
Topic
Citation
Moore, R., "Direct Methanol Fuel Cells for Automotive Power Systems," SAE Technical Paper 2000-01-0012, 2000, https://doi.org/10.4271/2000-01-0012.Also In
References
- Chu D. Gilman, S. J. Electrochem. Soc. 141 1770 1994
- Ren X. Zawodzinski T. A. Jr. Uribe F. Dai H. Gottesfeld S. Methanol Cross-over in Direct Methanol Fuel Cells “Proton Conducting Membrane Fuel Cells I” Gottesfeld S. Halpert G. Landgrebe A. The Electrochemical Society 95-23 Pennington, NJ 1995
- Wang, J.-T. Wasmus S. Savinell, R. F. J. Electrochem. Soc. 143 1223 1996
- Kauranen P. S. Skou E. J. Electroanal. Chem. 408 189 1996
- Ravikumar M. K. Shukla A. K. J. Electrochem. Soc. 143 2601 1996
- Cruickshank J. Scott K. J. Power Sources 70 40 1998
- Moore R. M. Gottesfeld S. Zelenay P. Optimizing the Overall Conversion Efficiency of a Direct-Methanol Fuel Cell “Proton Conducting Membrane Fuel Cells (Second International Symposium, Boston, November 1998)” Gottesfeld, S. Fuller T. F. Halpert G. 98-27 Electrochemical Society Pennington, New Jersey 1998
- Moore R. M. Gottesfeld S. Zelenay P. A Comparison of a Direct-Methanol Fuel Cell with a Direct-Hydrogen Fuel Cell “Proton Conducting Membrane Fuel Cells (Second International Symposium, Boston, November 1998)” Gottesfeld S. Fuller T. F. Halpert G. 98-27 Electrochemical Society Pennington, New Jersey 1998
- Ren X. Thomas S. C. Zelenay P. Gottesfeld S. Direct Methanol Fuel Cells: Developments for Portable Power and for Potential Transportation Applications “1998 Fuel Cell Seminar, Extended Abstracts” November 1998 Palm Springs, California
- Ford Motor Company Direct-Hydrogen-Fueled Proton-Exchange-Membrane Fuel Cell System for Transportation Applications February 1997
- Ford Motor Company Direct-Hydrogen-Fueled Proton-Exchange-Membrane Fuel Cell System for Transportation Applications March 1997
- Ford Motor Company Direct Hydrogen Fueled Proton Exchange Membrane Fuel Cell System for Transportation Applications July 1997
- Kalhammer F., et al. Section III.1.F, The Direct Methanol Fuel Cell (DMFC) http://www.arb.ca.gov/msprog/zevprog/fuelcell/fuelcell.htm
- American Methanol Institute Direct Methanol Fuel Cells http://www.methanol.org/fuelcell/fact/dmfc.html