Ageing and thermal conductivity of Porous Transport Layers used for PEM Fuel Cells

Burheim, Odne Stokke; Ellila, Georg; Fairweather, Joseph D.; Labouriau, Andrea; Kjelstrup, Signe; Pharoah, Jon G.

doi:10.1016/j.jpowsour.2012.08.027

Cited by 40 publications

(48 citation statements)

References 34 publications

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“…Finally, small MPL thermal conductivity differences would also likely be minimized by the presence of high water contents, which significantly increase the overall thermal conductivity of porous media. 50 From these observations, we conclude that the oxygen transport resistance differences between our different MPLs are not related to MPL thermal conductivity differences, but are mostly caused by an efficient liquid water transport as stated before.…”

Section: Discussionsupporting

confidence: 77%

Impact of Microporous Layer Pore Properties on Liquid Water Transport in PEM Fuel Cells: Carbon Black Type and Perforation

Simon

Kartouzian

Müller

et al. 2017

J. Electrochem. Soc.

110

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The oxygen and water transport through various microporous layers (MPLs) is investigated by fuel cell tests in a 5 cm 2 active area cell under differential-flow conditions, analyzing polarization curves, the associated high-frequency resistance, and the oxygen transport resistance extracted from limiting current density measurements. In this study, MPLs with two different carbon blacks are prepared and compared to a commercial material, all coated on the same GDL-substrate (Freudenberg); furthermore, perforated MPLs with large pores produced by a thermally decomposable polymeric pore former with a particle diameter of ≈30 μm are examined. The materials are characterized by mercury porosimetry, nitrogen adsorption and scanning electron microscopy. While at dry conditions (T cell = 80 • C, RH = 70%, p abs = 170 kPa) the performance of all materials is similar, at conditions of high water saturation (T cell = 50 • C, RH = 120%, p abs = 300 kPa), MPLs with larger pores or perforations exhibit a performance improvement due to a ≈30% reduction in oxygen transport resistance. The results indicate that liquid water is transported exclusively through these large pores, while the oxygen transport occurs in the small pores defined by the carbon black structure.

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Section: Discussionsupporting

confidence: 77%

Impact of Microporous Layer Pore Properties on Liquid Water Transport in PEM Fuel Cells: Carbon Black Type and Perforation

Simon

Kartouzian

Müller

et al. 2017

J. Electrochem. Soc.

110

View full text Add to dashboard Cite

show abstract

“…However, the thermal conductivity of porous materials is less straight forward and an assumption of proportionality between the amount of liquid and the thermal conductivity is wrong [28]. What is found to be the most important factor for a change in thermal conductivity of porous carbon materials is the contact between the solids [5,28]. Hence, the results given for each electrode material (dry and soaked) only give the lower and upper boundaries for what the thermal conductivity actually is.…”

Section: The Pouch Cellmentioning

confidence: 99%

Thermal Conductivity, Heat Sources and Temperature Profiles of Li-Ion Batteries

et al. 2014

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In this paper we report the thermal conductivity of several commercial and noncommercial Li-ion secondary battery electrode materials with and without electrolyte solvents. We also measure the Tafel potential, the ohmic resistance, reaction entropy and external temperature of a commercial pouch cell secondary Li-ion battery. Finally we combined all the experimentally obtained data in a thermal model and discuss the corresponding internal temperature effects.The thermal conductivity of dry electrode material was found to range from 0.07 to 0.41 W K −1 m −1 while the electrode material soaked in electrolyte solvent ranged from 0.36 to 1.10 W K −1 m −1 . For all the different materials it was found that adding the electrolyte solvent increased the thermal conductivity by at least a factor of three. For one of the anode materials it was found that heat treatment at 3000 K increased the thermal conductivity by a factor of almost five.Measuring the electric heat sources of an air cooled commercial pouch cell battery at up to ± 2C and the thermal conductivity of the electrode components made it possible to estimate internal temperature profiles. Combining the heat sources with tabulated convective heat transfer coefficients of air allowed us to calculate the ambient temperature profiles. At 12C charging rate (corresponding to 5 minutes complete charging) the internal temperature differences was estimated to be in the range of 4-20K, depending on the electrode thermal conductivity. The external temperature drop in air flowing at the battery surface was estimated to nearly 40K. Evaluating thermal * Corresponding author; odnesb@hist.no management of batteries in the light of our measurement led to the conclusion that external cooling is more challenging than internal, though neither should be neglected.

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“…This method does not mathematically guarantee complete deconvolution of parasitic resistances from the bulk conductivity. However, experiments show its promising capabilities not just for CLs in this study but also for other materials like GDLs which may not be available in different thicknesses due to manufacturing limitations [49][50][51][52][53]. Again, the relation for R tot remains the same as Eq.…”

Section: Through-plane Thermal Conductivity Measurementsmentioning

confidence: 92%

Characterization of Thermal and Electronic Conductivities of Catalyst Layers of Polymer Electrolyte Membrane Fuel Cells

et al. 2019

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This work proposes new and accurate systematic methodologies for ex situ measurements of through‐plane thermal and in‐plane electronic conductivities of catalyst layers (CLs) of polymer electrolyte membrane fuel cells (PEMFC). The developed methods are based on measurements of different thicknesses/lengths of a CL on different substrates. Suitability of the proposed methods is confirmed through a set of microstructural properties measurements on a typical CL design to ensure the measured CLs would be representative of CLs in a real fuel cell product. Conductivity measurements of two CL designs with different compositions and microstructures confirm capability of the developed procedures to track structural changes in CLs. The present characterization platform is not limited to CLs and may be used for other composite porous materials with similar structures.

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Ageing and thermal conductivity of Porous Transport Layers used for PEM Fuel Cells

Cited by 40 publications

References 34 publications

Impact of Microporous Layer Pore Properties on Liquid Water Transport in PEM Fuel Cells: Carbon Black Type and Perforation

Impact of Microporous Layer Pore Properties on Liquid Water Transport in PEM Fuel Cells: Carbon Black Type and Perforation

Thermal Conductivity, Heat Sources and Temperature Profiles of Li-Ion Batteries

Characterization of Thermal and Electronic Conductivities of Catalyst Layers of Polymer Electrolyte Membrane Fuel Cells

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