Water management along the flow channels of PEM fuel cells

Yi, Jung S.; Yang, Jangsik; King, Constance

doi:10.1002/aic.10307

Cited by 82 publications

(53 citation statements)

References 31 publications

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“…According to Fig. 11b, the net water drag coefficient for the symmetric configuration increases with increased current and goes from −0.005 (molH 2 . This observation is consistent with previously observed behavior for symmetric cells operating at dry conditions, where the dominant water transport regime is electro-osmosis toward the cathode, evaporation and removal through the free stream.…”

Section: 47mentioning

confidence: 94%

Water Management in Polymer Electrolyte Fuel Cells through Asymmetric Thermal and Mass Transport Engineering of the Micro-Porous Layers

Gandomi

Edmundson

Busby

et al. 2016

J. Electrochem. Soc.

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For polymer electrolyte fuel cells (PEFCs) operating at very high current, prevention of anode dry-out through enhanced back flux of water and restriction of evaporation is required. In this work, back flux of water to the anode is engineered using an asymmetric anode and cathode micro-porous layer (MPL) configuration. Extensive experimental tests have been conducted to study the impact of thermal and mass transport resistances on the net water flux coefficient for extremes of wet and dry operating conditions. The net water drag coefficient was measured in the range of −0.17 to +0.18 depending on the operating conditions and material configurations. A simplified model has also been developed to investigate the effect of temperature gradient on the net water drag coefficient. It is shown that with an asymmetric configuration, the net flux of water can be reversed under certain conditions, greatly enhancing high current density performance. For wet operating conditions, the cell configuration with asymmetric mass transport resistance can be utilized to tailor the back flux of water. For dry operating conditions, the thermal resistance is the key controlling parameter to affect the net water drag. Water management remains an important topic in polymer electrolyte fuel cell (PEFC) systems. Water is required to keep the membrane hydrated to maintain ionic conductivity. However, excessive liquid-water accumulation in the gas flow channels and in the porous media (gas diffusion layer (GDL), and catalyst layers) limits reactants' transport to the electrocatalyst (a phenomenon called flooding). The membrane's transport properties are known to be a strong function of water content within the membrane. Extensive dry-out at the anode side and subsequent conductivity loss results in poor overall performance. Several passive and active approaches have been utilized for water management within the PEFCs (e.g. Refs. 1-6). A good review of these techniques has been provided in Ref. 7 and a recent review of water transport within PEFCs is discussed in Ref. 8. The micro-porous layer (MPL) at the electrodes have been used to improve the performance of PEFC via water management. Pasaogullari et al.9 modeled the two-phase transport in the porous layers of a PEFC cathode side. Their modeling results predicted that the existence of a MPL in the cathode side enhances liquid-water removal and reduces liquid saturation in the catalyst layer. Weber and Newman 10 explored the effects of MPL in terms of water management using a two-phase flow and membrane model. Their simulation predicted that the MPL acts as a valve that pushes water away from the GDL in the cathode side through the membrane and accordingly minimizes flooding. Yan et al.11 measured the net water flux transferred across the membrane under various operating conditions. They measured the net flux coefficients ranging from +0.93 to −0.2 depending on the current density and humidification of feed gases. R. Zaffou et al. 12 quantified the temperature-gradient-driven water tr...

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Section: 47mentioning

confidence: 94%

Water Management in Polymer Electrolyte Fuel Cells through Asymmetric Thermal and Mass Transport Engineering of the Micro-Porous Layers

Gandomi

Edmundson

Busby

et al. 2016

J. Electrochem. Soc.

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“…A similar analysis was completed in 1-D by Yi et al 242 In both of these cases, the effect the liquid water has once it is formed in the channel is not rigorously accounted for, but the probable location for liquid-water formation is estimated.…”

Section: Gas-channel Analysesmentioning

confidence: 95%

“…A strategy that has been developed to counter this effect is to provide simultaneously a source and a sink for water by using a hydrophilic porous bipolar plate (called a water-transport plate, or WTP), which is filled with water and is maintained at a liquid pressure that is lower than the gas pressure. 242,271 By doing so, the reactants can be internally humidified throughout the entire planform, thereby minimizing dry regions, while at the same time excess water can be removed in the liquid phase through the WTP, thereby minimizing flooded regions.…”

Section: Water-transport Platesmentioning

confidence: 99%

Modeling Water Management in Polymer-Electrolyte Fuel Cells

Weber

Balliet

Gunterman

et al. 2008

Modern Aspects of Electrochemistry

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“…A promising and extensively tested approach towards water management is the use of porous bipolar plates, known as water-transport plates (WTPs), as practiced by UTC Power [10][11][12][13][14]. Figure 1 shows a performance curve for a fuel cell with WTPs, and Figure 2 shows a schematic of the cell.…”

Section: Introductionmentioning

confidence: 99%

Understanding porous water-transport plates in polymer-electrolyte fuel cells

Weber

Darling²

2007

Journal of Power Sources

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In this article, numerical simulations are used to compare polymer-electrolyte fuel cells with porous flow-field plates to cells with conventional solid plates. The model clarifies the role of the porous plates in humidifying dry reactant streams and managing liquid water. The influence of gas-diffusion-layer and bipolar-plate properties and coolant vacuum on the behavior of the cell is investigated.

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Water management along the flow channels of PEM fuel cells

Abstract: Water management is one of the most critical issues for high-performance polymer

Cited by 82 publications

References 31 publications

Water Management in Polymer Electrolyte Fuel Cells through Asymmetric Thermal and Mass Transport Engineering of the Micro-Porous Layers

Water Management in Polymer Electrolyte Fuel Cells through Asymmetric Thermal and Mass Transport Engineering of the Micro-Porous Layers

Modeling Water Management in Polymer-Electrolyte Fuel Cells

Understanding porous water-transport plates in polymer-electrolyte fuel cells

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