Model for the Prediction of Performance Behavior of a Solid Oxide Electrolyte Fuel Cell

The fundamental principles of thermodynamics, electrochemistry, transport phenomena, and chemical engineering science have been used to assemble and develop the formulation presented in this article.  The formulation can be employed to predict the electrical performance behavior of a high temperature solid oxide electrolyte fuel cell (SOEFC) with respect to, for example, the cell Nernst electrical voltage, actual(terminal) cell voltage, total cell voltage loss, electric voltage efficiency; the maximum, actual and Carnot cycle engine thermal efficiencies; and the ratio of the reversible heat to the total cell reaction thermal energy production.  Some of the conclusions drawn from the predicted data, with hydrogen as the fuel feed to a SOEFC, are as follows:

• The Nernst open-cell electric potential decreases with an increase in the temperature from 800 to 1100 K.
• The cell electric potential decreases with an increase in the hydrogen fractional conversion.
• The cell open-circuit electric potential is higher at a higher cathode-side oxidant (air) total pressure.
• The total cell voltage loss increases linearly with an increase in the geometric current density at

lower current densities; nonlinearly at higher current densities.

Ratio of the reversible thermal energy production (associated with the overall cell reaction entropy change) to the thermal energy production (associated with the overall cell reaction enthalpy change) increases almost linearly over the temperature range 800-1100 K.