Title: A model-based approach for current voltage analyses to quantify degradation and fuel distribution in solid oxide fuel cell stacks
Authors : Linder, Markus
Hocker, Thomas
Meier, Christoph
Holzer, Lorenz
Friedrich, Andreas
Iwanschitz, Boris
Mai, Andreas
Schuler, Andreas J.
Published in : Journal of Power Sources
Volume(Issue) : 288
Pages : 409
Pages to: 418
Publisher / Ed. Institution : Elsevier BV
Issue Date: 15-Aug-2015
Language : Englisch / English
Subjects : Degradation; Map; Stack; SOFC
Subject (DDC) : 621.3: Elektrotechnik, Elektronik
Abstract: Reliable quantification and thorough interpretation of the degradation of solid oxide fuel cell (SOFC) stacks under real conditions is critical for the improvement of its long-term stability. The degradation behavior is often analyzed based on the evolution of current–voltage (V,I) curves. However, these overall resistances often contain unavoidable fluctuations in the fuel gas amount and composition and hence are difficult to interpret. Studying the evolution of internal repeat unit (RU) resistances is a more appropriate measure to assess stack degradation. RU-resistances follow from EIS-data through subtraction of the gas concentration impedance from the overall steady-state resistance. In this work a model-based approach where a local equilibrium model is used for spatial discretization of a SOFC stack RU running on hydrocarbon mixtures such as natural gas. Since under stack operation, fuel leakages, uneven fuel distribution and varying natural gas composition can influence the performance, they are taken into account by the model. The model extracts the time-dependent internal resistance from (V,I)-data and local species concentration without any fitting parameters. RU resistances can be compared with the sum of the resistances of different components that allows one to make links between laboratory degradation experiments and the behavior of SOFC stacks during operation.
Departement: School of Engineering
Organisational Unit: Institute of Computational Physics (ICP)
Publication type: Beitrag in wissenschaftlicher Zeitschrift / Article in scientific Journal
DOI : 10.1016/j.jpowsour.2015.04.136
ISSN: 0378-7753
URI: https://digitalcollection.zhaw.ch/handle/11475/1631
Appears in Collections:Publikationen School of Engineering

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