Two-phase transport and the role of micro-porous layer in polymer electrolyte fuel cells

Pasaogullari, Ugur; Wang, Chao Yang

doi:10.1016/j.electacta.2004.04.027

Cited by 481 publications

(314 citation statements)

References 12 publications

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“…This is in agreement with previous analyses and PSDs of carbon paper GDLs [28,31,34]. Furthermore, the PSD of the MPL is very wide, which allows for less flooding and more control over water management [77,78]. On a pore-size basis, there is a significantly larger number of small pores located in the MPL than the GDL, but this changes if one examines the relative pore volumes (see equation 14).…”

Section: Updated Porous-medium Model and Modeling Methodologysupporting

confidence: 88%

Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

Weber¹

2010

Journal of Power Sources

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A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure -saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the steepness of the capillary pressuresaturation relationship. The model is also used to examine the impact of a microporous layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the water-injection sites into the more porous gas-diffusion layer.

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Section: Updated Porous-medium Model and Modeling Methodologysupporting

confidence: 88%

Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

Weber¹

2010

Journal of Power Sources

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“…Several GDL degradation mechanisms have been proposed: carbon oxidation [28,29], PTFE decomposition [30], and mechanical degradation as a result of compression [31]. The first two mechanisms cause hydrophobicity loss and changes in the GDL pore structure, resulting in an increase in the water content of the GDL and MPL and thus impeding gas phase mass transport [32][33][34]. It should be noted that the carbon fibers of the GDL and the carbon black particles of the MPL are more stable than the carbon black in the CL due to the absence of Pt that can catalyze the electrochemical oxidation of carbon.…”

Section: Gdl Degradationmentioning

confidence: 99%

A review of polymer electrolyte membrane fuel cell durability test protocols

Yuan

Zhang

et al. 2011

Journal of Power Sources

299

121

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a b s t r a c tDurability is one of the major barriers to polymer electrolyte membrane fuel cells (PEMFCs) being accepted as a commercially viable product. It is therefore important to understand their degradation phenomena and analyze degradation mechanisms from the component level to the cell and stack level so that novel component materials can be developed and novel designs for cells/stacks can be achieved to mitigate insufficient fuel cell durability. It is generally impractical and costly to operate a fuel cell under its normal conditions for several thousand hours, so accelerated test methods are preferred to facilitate rapid learning about key durability issues. Based on the US Department of Energy (DOE) and US Fuel Cell Council (USFCC) accelerated test protocols, as well as degradation tests performed by researchers and published in the literature, we review degradation test protocols at both component and cell/stack levels (driving cycles), aiming to gather the available information on accelerated test methods and degradation test protocols for PEMFCs, and thereby provide practitioners with a useful toolbox to study durability issues. These protocols help prevent the prolonged test periods and high costs associated with real lifetime tests, assess the performance and durability of PEMFC components, and ensure that the generated data can be compared.Crown

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“…182 MPL traits that lead to better performance include higher hydrophobicity, General models that compare strictly the difference in PEFC performance between having a MPL and not show that addition of a MPL leads to more uniform membrane hydration and gas and current distribution over the entirety of the PEFC. [192][193][194] One of the first MPL-specific works is that of Pasaogullari and Wang,195 who used a 1-D, half-cell, isothermal, and two-phase model to study the effects of MPL porosity, wettability, and thickness on performance. An interesting result stemmed from a comparison between their model and one that assumed a uniform gas pressure.…”

mentioning

confidence: 99%