Coupling continuum and pore-network models for polymer-electrolyte fuel cells

Abstract

Three novel iterative methodologies for coupling continuum and pore-network models (PNM) applied to polymer-electrolyte fuel cells (PEFCs) are presented. The modeling framework developed in this work merges the advantages of a continuum model, such as computational time, ease of implementation, and complicated physics, with those of relatively novel PNMs, such as discrete information on waterfront location and distribution. The outputs generated by the PNM are fed into the continuum model to compute electrochemical reaction rates and associated heat and mass fluxes. Out of three presented coupling methodologies, the most effective coupling is identified to be where locallyresolved effective diffusivity, thermal conductivity, and liquid permeability are computed with the PNM and fed into the continuum model and the fluxes from continuum model fed back into the PNM in an iterative scheme until solution convergence is reached. The described method is computationally efficient with stable convergence of less than five iterations. The proposed algorithms can be applied to multiple computational platforms and PEFC and related model architectures.

Understanding Water Transport in Polymer Electrolyte Fuel Cells Using Coupled Continuum and Pore‐Network Models

“…A thorough discussion of model coupling techniques can be found in an earlier publication [27]. The continuum model is a steady-state, two-phase, 2-D, nonisothermal, cross-section sandwich PEFC model.…”

“…A unique approach to combine the advantages of continuum and PN models, while mitigating the respective disadvantages, was undertaken to help explain observed variations in PEFC performance associated with the use of different GDL materials and morphologies [9]. Continuum models use a volume averaged approach to model two-phase water transport coupled with electrochemistry [10][11][12].…”

“…Both the cathode and anode GDLs begin with an uncoated backing that is treated using a 3M proprietary hydrophobization and microporous layer (MPL) treatments [8,27]. For the cathode, the GDL is referred to as U105 and for the anode the untreated experimental backing is provided by Freudenberg FFCT SE & Co., and the treated anode GDL is referred to as AEX1.…”

Microstructure-property relationships in a gas diffusion layer (GDL) for Polymer Electrolyte Fuel Cells, Part II: pressure-induced water injection and liquid permeability

“…Thereby, the permeability is Table 1 Summary of fit-parameters for Eqs. (8)- (12), which describe capillary properties and relative permeability of GDL. The fit-parameters were determined by Zamel et al [6] with the full morphology approach applied to a 3D reconstruction of a commercial GDL material (Toray TPGH-120 with 80% porosity).…”

“…Multi-physics modeling can be used to investigate the complex couplings between different transport processes and phase change reactions (including condensation-evaporation) in the PEM fuel cell [3,4,[8][9][10][11][12]. In order to simulate the cell behavior in a reliable and accurate way, a proper description of the relationship between the microstructure (including the morphology of the liquid water phase) and macro-homogeneous properties is urgently requested.…”