In this contribution, a dynamical nonlinear model structure for the identification of the electrical behavior of a solid oxide fuel cell is developed using expert knowledge from material scientists. The estimation of the model parameters can be realized by an iterative algorithm based on analytical equations to determine parameter estimates in each iteration step. An enhancement of the estimation can be achieved by an additional numerical optimization of the model parameters. Furthermore, this model can be extended to represent the time dependency of the model due to deterioration of the fuel cell materials. (c) 2005 Elsevier B.V. All rights reserved.