Quantification and characterization of water coverage in PEMFC gas channels using simultaneous anode and cathode visualization and image processing

Sergi, Jacqueline M.; Kandlikar, Satish G.

doi:10.1016/j.ijhydene.2011.06.092

Cited by 73 publications

(34 citation statements)

References 28 publications

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“…The instantaneous flow patterns and flow rates observed by Lu et al [23] in ex situ tests and by Sergi and Kandlikar [24] in situ tests were similar to those found by researchers using water injection at the entrance, confirming that the uniform water injection along the flow length does not introduce any new types of flow patterns. Using the instantaneous flow rate measurement and corresponding flow patterns, Kandlikar et al [19] and Lu et al [23] for ex situ, and Sergi and Kandlikar [24] for in situ experiments showed that the flow rate through a channel is dependent on the downstream flow pattern.…”

supporting

confidence: 82%

Modeling gas flow in PEMFC channels: Part I – Flow pattern transitions and pressure drop in a simulated ex situ channel with uniform water injection through the GDL

Grimm

See

Kandlikar

2012

International Journal of Hydrogen Energy

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supporting

confidence: 82%

Modeling gas flow in PEMFC channels: Part I – Flow pattern transitions and pressure drop in a simulated ex situ channel with uniform water injection through the GDL

Grimm

See

Kandlikar

2012

International Journal of Hydrogen Energy

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“…38 The impact of liquid water in the gas channel is accomplish with a modified Sherwood number 39 and by reducing the gas contact area using a surface-coverage ratio. 40 In the GDM, the characterization of diffusion and governing parameters has been accomplished using various experiments combined with simple limiting-current or Fickian-type diffusion equations to get the values for use in equation 7 or 8. [41][42][43][44] A more direct in-situ measurement of oxygen diffusion resistance has been presented in previous work by Baker et al 38 and Caulk et al 45 that established a method and analysis using limiting-current measurements under dry and oversaturated conditions for use in equation 7 or 8.…”

Section: Journal Of the Electrochemical Society 161 (12) F1254-f1299mentioning

confidence: 99%

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Weber

Borup

Darling³

et al. 2014

J. Electrochem. Soc.

509

394

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Polymer-electrolyte fuel cells are a promising energy-conversion technology. Over the last several decades significant progress has been made in increasing their performance and durability, of which continuum-level modeling of the transport processes has played an integral part. In this review, we examine the state-of-the-art modeling approaches, with a goal of elucidating the knowledge gaps and needs going forward in the field. In particular, the focus is on multiphase flow, especially in terms of understanding interactions at interfaces, and catalyst layers with a focus on the impacts of ionomer thin-films and multiscale phenomena. Overall, we highlight where there is consensus in terms of modeling approaches as well as opportunities for further improvement and clarification, including identification of several critical areas for future research. Fuel cells may become the energy-delivery devices of the 21 st century. Although there are many types of fuel cells, polymer-electrolyte fuel cells (PEFCs) are receiving the most attention for automotive and small stationary applications. In a PEFC, fuel and oxygen are combined electrochemically. If hydrogen is used as the fuel, it oxidizes at the anode releasing proton and electrons according toThe generated protons are transported across the membrane and the electrons across the external circuit. At the cathode catalyst layer, protons and electrons recombine with oxygen to generate waterAlthough the above electrode reactions are written in single step, multiple elementary reaction pathways are possible at each electrode. During the operation of a PEFC, many interrelated and complex phenomena occur. These processes include mass and heat transfer, electrochemical reactions, and ionic and electronic transport. * Electrochemical Society Active Member. z E-mail: azweber@lbl.govOver the last several decades significant progress has been made in increasing PEFC performance and durability. Such progress has been enabled by experiments and computation at multiple scales, with the bulk of the focus being on optimizing and discovering new materials for the membrane-electrode-assembly (MEA), composed of the proton-exchange membrane (PEM), catalyst layers, and diffusionmedia (DM) backing layers. In particular, continuum modeling has been invaluable in providing understanding and insight into processes and phenomena that cannot be resolved or uncoupled through experiments. While modeling of the transport and related phenomena has progressed greatly, there are still some critical areas that need attention. These areas include modeling the catalyst layer and multiphase phenomena in the PEFC porous media.While there have been various reviews over the years of PEFC modeling 1-7 and issues, [8][9][10][11][12][13][14] as well as numerous books and book chapters, there is a need to examine critically the field in terms of what has been done and what needs to be done. This review serves that purpose with a focus on transport modeling of PEFCs. This is not meant to be an exhaustive review...

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“…A number of visualisation techniques were applied to monitor the water distribution and transport in different parts of PEMFC including fluorescence microscopy [125], Environmental Scanning Electron Microscope (ESEM) [88,126], X-Ray radiography [127][128][129][130][131][132][133], X-Ray tomography [134], neutron radiography [135][136][137], magnetic resonance [138], and video cameras [139][140][141][142][143]. An overview of these experimental techniques can be found in [144,145].…”

Section: Water Distribution and Transportmentioning

confidence: 99%

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Ous

Arcoumanis

2013

Journal of Power Sources

137

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThis review paper summarises the key aspects of Proton Exchange Membrane Fuel Cell (PEMFC) degradation that are associated with water formation, retention, accumulation, and transport mechanisms within the cell. Issues related to loss of active surface area of the catalyst, ionomer dissolution, membrane swelling, ice formation, corrosion, and contamination are also addressed and discussed. The impact of each of these water mechanisms on cell performance and durability was found to be different and to vary according to the design of the cell and its operating conditions. For example, the presence of liquid water within Membrane Electrode Assembly (MEA), as a result of water accumulation, can be detrimental if the operating temperature of the cell drops to sub-freezing.The volume expansion of liquid water due to ice formation can damage the morphology of different parts of the cell and may shorten its life-time. This can be more serious, for example, during the water transport mechanism where migration of Pt particles from the catalyst may take place after detachment from the carbon support. Furthermore, the effect of transport mechanism could be augmented if humid reactant gases containing impurities poison the membrane, leading to the same outcome as water retention or accumulation.Overall, the impact of water mechanisms can be classified as aging or catastrophic. Aging has a longterm impact over the duration of the PEMFC life-time whereas in the catastrophic mechanism the impact is immediate. The conversion of cell residual water into ice at sub-freezing temperatures by the water retention/ accumulation mechanism and the access of poisoning contaminants through the water transport mechanism are considered to fall into the catastrophic category. The effect of water mechanisms on PEMFC degradation can be reduced or even eliminated by (a) using advanced materials for improving the electrical, chemical and mechanical stability of the cell components against deterioration, and (b) implementing effective strategies for water management in the cell.

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Quantification and characterization of water coverage in PEMFC gas channels using simultaneous anode and cathode visualization and image processing

Cited by 73 publications

References 28 publications

Modeling gas flow in PEMFC channels: Part I – Flow pattern transitions and pressure drop in a simulated ex situ channel with uniform water injection through the GDL

Modeling gas flow in PEMFC channels: Part I – Flow pattern transitions and pressure drop in a simulated ex situ channel with uniform water injection through the GDL

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

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