Coupled pore network model for the cathode gas diffusion layer in PEM fuel cells
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RESEARCH PAPER
Coupled pore network model for the cathode gas diffusion layer in PEM fuel cells Hamed Gholipour1 · Mohammad J. Kermani1 · Rahim Zamanian2 Received: 29 September 2019 / Revised: 18 August 2020 / Accepted: 8 September 2020 © The Chinese Society of Theoretical and Applied Mechanics and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A pore network model (PNM) is developed for gas diffusion layer (GDL) in the cathode side of polymer electrolyte membrane fuel cells (PEMFCs). The model is coupled to network models of reactant oxygen and electron transport inside GDL and also to simple models of catalyst layer and membrane. The coupled model captures the simultaneous effect of reactant and charge access to reaction sites and the resulting water generation, allowing it a transient nature up to reaching the steady state, which is a notable modification to the available PNMs which assume uniform invasion of liquid water from catalyst layer. The results show strongly non-uniform water saturation distributions inside GDL with maxima under the current collector ribs. As an extra feature, the model can predict time evolution of oxygen concentration and water generation rate at catalyst layer as a result of liquid water build-up in GDL. Also included is a dry case coupled model in order to be compared with the main model. The local water blockages in GDL inflict an average of 38.8% loss on the produced limiting current of the fuel cell. Finally, the coupling allows prediction of concentration overvoltages which emerges to be most pronounced in the under-rib region. Keyword Pore network model · Gas diffusion layer · Fuel cells · Gas channel-rib · Coupling
1 Introduction Polymer electrolyte membrane fuel cells (PEMFCs) are extensively deemed as the upcoming power generation units which are considered as optimistic alternatives to internal combustion engines to be utilized in automotive industries. However, the implementation and commercialization of PEMFCs have been questioned by the prohibitive cost, size and power density, water management issue, etc. [1]. The typical PEMFC is made up of a cathode and an anode side each comprising a porous gas diffusion layer (GDL) and a more delicate catalyst layer (CL) as electrode which is where the reaction takes place. There is a thin polymer electrolyte membrane in the middle being sandwiched by the two sides transferring protons from anode to the cath-
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Mohammad J. Kermani [email protected]
1
Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 15875-4413 Tehran, Iran
2
International Campus, Amirkabir University of Technology (Tehran Polytechnic), 15875-4413 Tehran, Iran
ode side. PEMFCs exploiting an electrochemical process for generating electricity generate heat and water as an indispensable product of the reaction. The fibrous GDL provides pathways for the reactants, electrons and products between the gas channels (GCs) or the current collector ribs and the reaction sites. The cathode side transpo
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