Investigating the Water Transport in Porous Media for PEMFCs by Liquid Water Visualization in ESEM

Alink, Robert; Gerteisen, Dietmar; Mérida, Walter

doi:10.1002/fuce.201000110

Cited by 50 publications

(27 citation statements)

References 21 publications

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“…The high standard deviation is consistent with confined breakthrough locations caused by regions with lower intrusion pressure. This "fingering effect"was also found in different percolation experiments [10,24]. Figure 6.…”

Section: Saturation Distributionmentioning

confidence: 64%

“…Pore network models are very helpful for understanding the general dependencies of the liquid water transport phenomena in porous materials for fuel cells [17][18][19][20][21][22][23]. In contrast to continuum models, they are able to capture the complex liquid water fingering transport processes, observed in ex situ experiments for highly porous and hydrophobic materials [10,24]. The GDL is represented by regularly shaped pores, which are interconnected by regularly shaped throats, presuming the connectivity.…”

Section: Introductionmentioning

confidence: 99%

“…Adding artificial water transport channels by laser perforation has been shown to improve the water management, which is most likely due to a drainage effect in the GDL [9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Alink

Gerteisen

2013

Energies

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In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

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Section: Saturation Distributionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

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Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Alink

Gerteisen

2013

Energies

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“…The deformable MEA, fabricated in a novel configuration, can be constrained in a limited space for both stationary and portable power sources [4][5][6][7]. One of the major design considerations is the water flooding in the MEA, arising from the blockage of gas diffusion layer by the generated water in cathode catalyst layer [8,9].…”

Section: Introductionmentioning

confidence: 99%

Mathematical Model of Proton Exchange Membrane Fuel Cell with Consideration of Water Management

Yin

Hsuen

2013

Fuel Cells

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One‐dimensional model on the membrane electrode assembly (MEA) of proton exchange membrane fuel cell is proposed, where the membrane hydration/dehydration and the possible water flooding of the respective cathode and anode gas diffusion layers are considered. A novel approach of phase‐equilibrium approximation is proposed to trace the water front and the detailed saturation profile once water emerges in either anode or cathode gas diffusion layer. The approach is validated by a semi‐analytical method published earlier. The novel approach is applicable to the polarization regime from open circuit voltage to the limiting current density under practical operation conditions. Oxygen diffusion is limited by water accumulation in the cathode gas diffusion layer as current increases, caused by excessive water generation at the cathode catalyst layer and the electro‐osmotic drag across the membrane. The existence of liquid water in the anode gas diffusion layer is predicted at low current densities if high degrees of humidification in both anode and cathode feeds are employed. The influences of inlet relative humidity, imposed pressure drop, and cell temperature are correlated well with the cell performance. In addition, the overpotentials attributed from individual components of the MEA are delineated against the cell current densities.

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“…More recently, several researchers have shown an improvement in fuel cell performance at different operating conditions by perforating and/or making grooves to conventional CFPs. [9][10][11][12][13][14] In this study, in-situ experiments of perforated stainless steel sheets as GDLs were performed to study the effects of different engineered sheet designs on the performance and transport characteristics inside a PEMFC. …”

mentioning

confidence: 99%

Perforated Metal Sheets as Gas Diffusion Layers for Proton Exchange Membrane Fuel Cells

Blanco

Wilkinson

Wang

2012

Electrochem. Solid-State Lett.

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The use of perforated metal sheets as engineered gas diffusion layers (GDL) in proton exchange membrane (PEM) fuel cells was investigated. The effect of different thicknesses, perforation diameter, and in-plane diffusion capabilities were analyzed along with freestanding microporous layers in order to improve gas and water transport. Although these structured GDLs are in an early stage of development, they provide baseline performance at lower current densities, and may already have potential for some specific applications. In addition, the design, manufacturing, and modeling processes with predictive capability can be improved due to their simplified nature.The two materials used the most as gas diffusion layers (GDL) in the proton exchange membrane fuel cell (PEMFC) industry are carbon fiber papers (CFP) and carbon cloths (CC). 1 However, they have a number of drawbacks, particularly with respect to their design and model complexity. One of the main issues with the CFP/CC used as GDLs is the non-controlled variation in porosity (and other localized properties) since the porosity characteristics between CFP are not always repeatable. 2 Many of the water management and mass transport issues with GDLs could be improved considerably if the GDLs could be carefully tailored to specific fuel cell applications.One approach to the design of these engineered GDLs is through the use of non-porous conductive materials that are perforated based on a detailed design. Research groups from Ballard Power Systems and Graftech Inc. have presented designs of engineered GDLs based on graphitic foils. 3, 4 A number of different designs (e.g., geometry, cross-sectional shape, and hole density) were also proposed. Unfortunately, to the best of our knowledge, there are limited published results from Graftech but none from Ballard that show complete studies of how these perforated graphitic foils perform inside a fuel cell. Other groups have also proposed other non-porous materials as engineered GDLs. 5, 6 None of these studies attempted to understand in detail how the proposed GDLs affected fuel cell performance.Another approach to develop engineered GDLs is through the use of perforations and grooves in CFPs and the weave design in CCs. Based on the earlier work of Wilkinson et al.,7,8 the main idea behind the modification of porous CFPs with perforations is to improve liquid water transport at specific locations of the GDL. More recently, several researchers have shown an improvement in fuel cell performance at different operating conditions by perforating and/or making grooves to conventional CFPs. [9][10][11][12][13][14] In this study, in-situ experiments of perforated stainless steel sheets as GDLs were performed to study the effects of different engineered sheet designs on the performance and transport characteristics inside a PEMFC. ExperimentalFor all the measurements, a single cell fuel cell with an active area of 49 cm 2 was used. The perforated sheets (PS) were made out of stainless 316L steel sheets and were perforated by V...

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Investigating the Water Transport in Porous Media for PEMFCs by Liquid Water Visualization in ESEM

Cited by 50 publications

References 21 publications

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Mathematical Model of Proton Exchange Membrane Fuel Cell with Consideration of Water Management

Perforated Metal Sheets as Gas Diffusion Layers for Proton Exchange Membrane Fuel Cells

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