A Multiscale Approach to the Numerical Simulation of the Solid Oxide Fuel Cell

Abstract

The models of solid oxide fuel cells (SOFCs), which are available in the open literature,may be categorized into two non-overlapping groups: microscale or macroscale. Recent progressin computational power makes it possible to formulate a model which combines both approaches,the so-called multiscale model. The novelty of this modeling approach lies in the combination ofthe microscale description of the transport phenomena and electrochemical reactions’ with thecomputational fluid dynamics model of the heat and mass transfer in an SOFC. In this work,the mathematical model of a solid oxide fuel cell which takes into account the averaged microstructureparameters of electrodes is developed and tested. To gain experimental data, which are used toconfirm the proposed model, the electrochemical tests and the direct observation of the microstructurewith the use of the focused ion beam combined with the scanning electron microscope technique(FIB-SEM) were conducted. The numerical results are compared with the experimental data fromthe short stack examination and a fair agreement is found, which shows that the proposed modelcan predict the cell behavior accurately. The mechanism of the power generation inside the SOFC isdiscussed and it is found that the current is produced primarily near the electrolyte–electrode interface.Simulations with an artificially changed microstructure does not lead to the correct prediction of thecell characteristics, which indicates that the microstructure is a crucial factor in the solid oxide fuelcell modeling.