Oxygen transport resistance correlated to liquid water saturation in the gas diffusion layer of PEM fuel cells

In this work, an accurate and computationally fast model for liquid water transport within a proton exchange membrane fuel cell (PEMFC) electrode is developed by lumping the space-dependence of the relevant variables. Capillarity is considered as the main transport mechanism within the gas diffusion layer (GDL). The novelty of the model lies in the simulation of the water transport at the interface between gas diffusion layer and gas flow channel (GFC). This is achieved with a phenomenological description of the process that allows its simulation with relative simplicity. Moreover, a detailed two-dimensional visualization of such interface is achieved via geometric simulation of water droplets formation, growth, coalescence and detachment on the surface of the GDL. The accomplishment of reduced computational time and good accuracy makes the model suitable for control strategy implementation to ensure PEM fuel cells operation within optimal electrode water content. Furthermore, the model is useful for optimization analysis oriented to both PEMFC design and balance of plant.

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Wetting-Dependent Percolation through the Gas Diffusion Layer of PEM Fuel Cells

ECS Meeting Abstracts ◽

10.1149/ma2018-02/41/1374 ◽

2018 ◽

Keyword(s):

Fuel Cells ◽

Diffusion Layer ◽

Gas Diffusion Layer ◽

Pem Fuel Cells ◽

Gas Diffusion ◽

Dependent Percolation

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Numerical Study of Liquid Water Saturation inside Gas Diffusion Layer and Micro Porous Layer during PEMFC Operations Using Multiscale and Multiphase Modeling Approach

ECS Meeting Abstracts ◽

10.1149/ma2018-02/41/1369 ◽

2018 ◽

Keyword(s):

Porous Layer ◽

Diffusion Layer ◽

Liquid Water ◽

Water Saturation ◽

Numerical Study ◽

Gas Diffusion Layer ◽

Gas Diffusion ◽

Modeling Approach ◽

Multiphase Modeling

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Effect of the Micro-Porous Layer-Gas Diffusion Layer Interface on Water Transport in Polymer Electrolyte Fuel Cells

ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology ◽

10.1115/fuelcell2009-85127 ◽

2009 ◽

Author(s):

Joshua Preston ◽

Richard Fu ◽

Xiaoyu Zhang ◽

Ugur Pasaogullari

Keyword(s):

Polymer Electrolyte ◽

Cross Section ◽

Porous Layer ◽

Diffusion Layer ◽

Liquid Water ◽

Water Saturation ◽

Numerical Models ◽

Gas Diffusion Layer ◽

Gas Diffusion ◽

Diffusion Media

An investigation of the liquid water saturation across the cross-section of an operating polymer electrolyte fuel cell is performed to analyze the saturation discontinuity predicted by numerical models. Numerical models have predicted a discontinuity in the liquid water saturation at the interface of the micro-porous layer and the coarser macroporous region of the gas diffusion layer. High-resolution through plane neutron radiography is used to acquire the water content distribution across the thickness of the gas-diffusion layer and study the effects of the interface. The measured liquid water profiles indicate no obvious discontinuity in the liquid water saturation across the cross-section of the bi-layer gas diffusion layer when large areas are averaged spatially. Evidence of the discontinuity is found when small spatial averaging is used in certain locations. Other locations show no evidence of the discontinuity. Scanning electron microscopy is used to examine the microstructure of two types of the bi-layer diffusion media. The images show that the approximation of the interface as a sudden, distinct feature may not be appropriate. The results suggest that a model that considers the existence of an interfacial region in the diffusion media may be appropriate, in which the properties vary continuously.

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