X-ray computed tomography of gas diffusion layers of PEM fuel cells: Calculation of thermal conductivity

Pfrang, Andreas; Veyret, D.; Sieker, F.; Tsotridis, Georgios

doi:10.1016/j.ijhydene.2010.01.085

Cited by 58 publications

(48 citation statements)

References 25 publications

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“…A carbon cloth is shown as sample X-ray computed tomography (Ostadi et al, 2008;Pfrang et al, 2010) as well as synchrotron based tomography (Becker et al, 2008;Becker et al, 2009) have been used for imaging of gas diffusion layers at resolutions below 1 µm. Also membranes and membrane electrode assemblies (Garzon et al, 2007;Pfrang et al, 2011) have been imaged by X-ray computed tomography and even functioning fuel cells have been imaged by synchrotron-based methods and soft X-ray radiography e.g.…”

Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

“…for imaging of liquid water in the GDL (Sinha et al, 2006;Bazylak, 2009;Sasabe et al, 2010;Tsushima & Hirai, 2011 Table 1. Properties of gas diffusion layers investigated by X-ray computed tomography (Toray Industries, 2005b;SGL Group, 2009;Pfrang et al, 2010) Here, CT data from three different commercially available gas diffusion layers will be discussed which were imaged by a nanotom X-ray computed tomography system (GE Sensing and Inspection Technologies, phoenix X-ray, Wunstorf, Germany) at a resolution below 1 µm. Table 1 shows PTFE content, thickness and porosity of the investigated gas diffusion layers.…”

Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

“…carbon and PTFE) and air was carried out based on a gray level threshold. Further details can be found in (Pfrang et al, 2010).…”

Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

“…As more accurate thermal conductivity data is required, one further approach is the computation based on 3D structure data (Becker et al, 2008;Pfrang et al, 2010;Zamel et al, 2010). Fig.…”

Section: Computation Of Thermal Conductivity Of Gas Diffusion Layersmentioning

confidence: 99%

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Computation of Thermal Conductivity of Gas Diffusion Layers of PEM Fuel Cells

Pfrang¹,

Veyret²,

Tsotridis³

2011

Convection and Conduction Heat Transfer

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Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

“…carbon and PTFE) and air was carried out based on a gray level threshold. Further details can be found in (Pfrang et al, 2010).…”

Section: Fig 2 Principle Of X-ray Computed Tomography (Ct)mentioning

confidence: 99%

“…As more accurate thermal conductivity data is required, one further approach is the computation based on 3D structure data (Becker et al, 2008;Pfrang et al, 2010;Zamel et al, 2010). Fig.…”

Section: Computation Of Thermal Conductivity Of Gas Diffusion Layersmentioning

confidence: 99%

See 2 more Smart Citations

Computation of Thermal Conductivity of Gas Diffusion Layers of PEM Fuel Cells

Pfrang¹,

Veyret²,

Tsotridis³

2011

Convection and Conduction Heat Transfer

Self Cite

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“…Until recently, the main technique used to determine the GDL structure was scanning electron microscopy (SEM), frequently coupled with energy dispersive X-ray spectroscopy (EDS) analysis. SEM is useful in obtaining surface structural data, layer thickness, 'smoothness' of different interfaces, PTFE bonding, and fibre orientation, but fails to reveal the porosity and internal structure [5,6,[15][16][17][18][19][20][21][22]. Micro and nano X-ray computed tomography (CT) are non-destructive methods that can achieve sufficiently high resolution for the imaging of carbon fibres, which typically have diameters between 5 and 10 m, and they have been increasingly used to characterise GDLs [7,19,[23][24][25][26].…”

mentioning

confidence: 99%

Effect of gas diffusion layer properties on water distribution across air-cooled, open-cathode polymer electrolyte fuel cells: A combined ex-situ X-ray tomography and in-operando neutron imaging study

Meyer

Ashton

Boillat

et al. 2016

Electrochimica Acta

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2 Highlights First description of in-plane water distribution using neutron imaging in an aircooled, open-cathode fuel cell. High water content identified under cathode land area, whereas anode water content is relatively homogeneous. Water distribution in anode GDL directly linked to dispersion of PTFE. Anode GDL composition shown to affect water content and distribution in cathode. Combined X-ray computed tomography, SEM/EDS and TGA used to characterise GDL structure and composition. AbstractIn-situ diagnostic techniques provide a means of understanding the internal workings of fuel cells under normal operating conditions so that improved designs and operating regimes can be identified. Here, an approach is used which combines exsitu characterisation of two anode gas diffusion / microporous layers (GDL-A and GDL-B) with X-ray computed tomography and in-situ analysis using neutron imaging of operating fuel cells. The combination of TGA, SEM and X-ray computed tomography reveals that GDL-A has a thin microporous layer with 26 % PTFE covering a thick diffusion layer composed of 'spaghetti' shaped fibres. GDL-B is covered by two microporous media (29 % and 6.5 % PTFE) penetrating deep within the linear fibre network. The neutron imaging reveals two pathways for water management underneath the cooling channel, either diffusing through the cathode GDL to the active channels, or diffusing through the membrane and towards the 3 anode. Here, these two behaviours are directly affected by the anode gas diffusion PTFE content and porosity. KeywordsGas diffusion layer; air-cooled open-cathode; X-ray computed tomography; neutron imaging; water management. IntroductionPolymer electrolyte fuel cells (PEFC) fuelled with hydrogen are among the most promising energy conversion technologies for a broad range of applications, including portable, stationary and automotive power delivery. However, understanding the cell water management is crucial for performance optimisation.Flooding impedes reactant transport (water mainly concentrating at the cathode) and reduces the surface area of the catalyst, causing significant if not catastrophic decay in cell performance, and dehydration can lead to cracks and irreversible damage [1][2][3]. The gas diffusion layer (GDL) provides a pathway for electron transport, ensures even reactant delivery and helps water management within each cell. The water balance between flooding and membrane dehydration is a function of the GDL's structure, porosity and PTFE (hydrophobic) content. Here, two commercial GDLs with microporous layers are characterised ex-situ by capturing the design and structure via X-ray computed tomography (CT), along with its polytetrafluoroethylene (PTFE) / carbon distribution via SEM/EDS analysis and thermogravimetric analysis (TGA); in-situ 'visualisation' of the water distribution in the in-plane orientation was performed using neutron radiography. These techniques can be correlated with one another to gain new insights into the water management role of the GDL in fuel c...

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In Situ and Operando Characterization of Proton Exchange Membrane Fuel Cells

2019

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For proton-exchange-membrane fuel cells (PEMFCs) to become a mainstream energy source, significant improvements in their performance, durability, and efficiency are necessary. To improve their durability, there must be a solid understanding of how the structural and electrochemical processes are affected during operation to propose mitigation strategies. To this aim, in situ and operando characterization techniques locally identify structural and electrochemical processes, which cannot be captured using conventional techniques. Nevertheless, linking these properties in the same geometric area has been challenging due to its inherent limitations, such as sample size and imaging resolution. This has created a knowledge gap in structure-to-electrochemical performance relationships as operation and degradation unevenly affect different areas of the cell.

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X-ray computed tomography of gas diffusion layers of PEM fuel cells: Calculation of thermal conductivity

Cited by 58 publications

References 25 publications

Computation of Thermal Conductivity of Gas Diffusion Layers of PEM Fuel Cells

Computation of Thermal Conductivity of Gas Diffusion Layers of PEM Fuel Cells

Effect of gas diffusion layer properties on water distribution across air-cooled, open-cathode polymer electrolyte fuel cells: A combined ex-situ X-ray tomography and in-operando neutron imaging study

In Situ and Operando Characterization of Proton Exchange Membrane Fuel Cells

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