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DMFC system design for portable applications

Fuel Cell Technology and Applications

Direct methanol fuel cells and systems (DMFC)

  1. S. R. Narayanan,
  2. T. I. Valdez,
  3. N. Rohatgi

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f306075

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Narayanan, S. R., Valdez, T. I. and Rohatgi, N. 2010. DMFC system design for portable applications. Handbook of Fuel Cells. .

Author Information

  1. Jet Propulsion Laboratory, Pasadena, CA, USA

Publication History

  1. Published Online: 15 DEC 2010

Abstract

Direct methanol fuel cells (DMFCs) in portable applications are expected to provide substantially higher energy density and longer operating times over advanced batteries. The time threshold of advantage of using a fuel cell instead of a battery is almost independent of the power level, and is determined by the power density of the fuel cell and its operating efficiency. The various requirements for portable fuel cells that determine system design are defined with examples. The system design process and analysis methods are illustrated. The characteristics of cells and stacks required for system design are described. The dependence of DMFC stack performance on airflow rate, methanol concentration and temperature are necessary for developing closed loop mathematical models for system design. Such a closed loop system model has been developed and the consequences of varying airflow rate on water recovery, thermal management and overall system performance have been analyzed. Using this model, the effect of crossover rate on the overall efficiency, power density and the operating methanol concentrations have also been investigated. Effect of components on the overall power budget and design issues relating to start-up and transient response are also discussed.

Keywords:

  • direct methanol fuel cell;
  • portable fuel cell requirements;
  • system model;
  • water recovery;
  • efficiency;
  • crossover rate;
  • system design;
  • closed loop operation;
  • methanol sensor