Various phenomena occur in the fuel cell such as mass transfer, electrochemical reactions and charge transfer. Available SOFC CSTR models avoid using charge balance equations in dynamic simulations. This paper focuses on developing a modified CSTR SOFC model with a charge balance equation. In compliance with the electromagnetic theory, the charge balance equation is defined for electrode / electrolyte interface.

Modelling of transfer processes is used in fuel cell design for understanding of complex phenomena and identification of critical parameters with great impact on performance. Mathematical modelling and analysis are used to predict the fuel cell behaviour under a variety of conditions and to investigate the effect of various processing and operating parameters. To validate the model we compare the model behaviour with the process behaviour.

The unsteady-state CSTR SOFC model is suitable for numerical impedance analysis. Numerical impedance experiment consists in imposing a sinusoidal voltage signal to the electrochemical fuel cell model and simulating the respond of the cell. The impedance is the ratio of AC voltage and current output.

To improve fuel cell design, there is a great need to identify, understand and predict fuel cell behaviour for control purpose. The developed unsteady-state CSTR SOFC model with charge balance will provide a better understanding of main phenomena governing electrochemical reactions in fuel cells.