A new analytical approach to model and evaluate the performance of a class of irreversible fuel cells

An irreversible model of a class of hydrogen-oxygen fuel cells working at steady-state is established, in which the irreversibilities resulting from electrochemical reaction, electrical resistance, and heat transfer to the environment are taken into account. The entropy production analysis is introduced and applied to investigate the physical and chemical performances of the fuel cell by using the theory of electrochemistry and non-equilibrium thermodynamics. Expressions for the power output and efficiency of the fuel cell are derived by introducing the equivalent internal and leakage resistances. With the help of the model being applied to high temperature solid oxide fuel cells, the performance characteristic curves of the fuel cell are presented and the influence of some design and operating parameters on the performance of the fuel cell are discussed in detail. Moreover, the optimum criteria of some important parameters such as the power output, efficiency, and current density are given. The results obtained may provide a theoretical basis for both the optimal design and operation of real fuel cells. This new method can also be used in the investigation and optimization of similar energy conversion settings and electrochemistry systems. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.