Visualization of liquid water in a lung-inspired flow-field based polymer electrolyte membrane fuel cell via neutron radiography

Cho, J.I.S.; Neville, Tobias P.; Trogadas, Panagiotis; Meyer, Quentin; Wu, Yunsong; Ziesche, R.; Boillat, Pierre; Cochet, Magali; Manzi-Orezzoli, Victoria; Shearing, Paul R.; Brett, Dan J. L.; Coppens, MO

doi:10.1016/j.energy.2018.12.143

Cited by 94 publications

(62 citation statements)

References 67 publications

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“…Graphite based flow-fields are used in this study, making the system representative of many fuel cell systems. However, it is well known that the nature of the channel wall material (specifically its roughness, and hydrophilic/phobic nature, can affect the way in which water wets and accumulates in channels [46], [47]. This must, therefore, be considered when considering the water management of any…”

Section: Resultsmentioning

confidence: 99%

Effect of compression on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Cho

et al. 2019

Journal of Power Sources

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In-depth understanding of the effect of compression on the water management in polymer electrolyte fuel cells (PEFCs) is indispensable for optimisation of performance and durability. Here, in-operando neutron radiography is utilised to evaluate the liquid water distribution and transport within a PEFC under different levels of compression. A quantitative analysis is presented with the influence of compression on the water droplet number and median droplet surface area across the entire electrode area. Water management and performance of PEFCs is strongly affected by the compression: the cell compressed at 1.0 MPa demonstrates ~3.2% and ~7.8% increase in the maximum power density over 1.8 MPa and 2.3 MPa, respectively. Correlation of performance to neutron radiography reveals that the performance deviation in the mass transport region is likely due to flooding issues. This could be ascribed to the loss of the porosity and increased tortuosity factor of the gas diffusion layer under the land at higher compression pressure. The size and number of droplets formed as a function of cell compression was examined: with higher compression pressure, water droplet number and median droplet surface area rapidly increase, showing the ineffective water removal, which leads to fuel starvation and the consequent performance decay.

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Section: Resultsmentioning

confidence: 99%

Effect of compression on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Cho

et al. 2019

Journal of Power Sources

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“…The advantages of the 3D lung-inspired design compared to the serpentine design (Trogadas et al, 2018) were: (i) low pressure drop (minimum entropy production); (ii) uniform reactant distribution for both low and high temperatures; (iii) high electrocatalyst stability; (iv) easy scalability. The disadvantage was that the design is more vulnerable for flooding than serpentine design (Cho et al, 2019).…”

Section: Lung-shaped Designsmentioning

confidence: 99%

Flow Field Patterns for Proton Exchange Membrane Fuel Cells

et al. 2020

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Flow field designs for the bipolar plates of the proton exchange membrane fuel cell are reviewed; including the serpentine, parallel, interdigitated, mesh type or their mixtures, furthermore 2D circular and 3D tubular geometries, porous, fractal, and biomimetic flow fields. The advantages/disadvantages and tendencies from field optimizations are discussed. The performance of each flow field design is compared to the conventional serpentine flow field. Good flow field plates give uniform gas distributions, low pressure drop for transport, and sufficient rib area to provide high electronic conductivity. A good field should also prevent water condensation, remove water efficiently, and provide sufficiently high moisture content in the membrane. The demands on design are sometimes contradictory. Future work should aim for a flow field geometry and topology that produces uniform gas delivery at a low pressure-drop, and at the same time has an optimal channel shape for better water removal. It is concluded that for an area-filling gas distributor, the developments should aim to find a flow field in accordance with minimum entropy production, making an emphasis on multi-criteria optimization methods.

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“…1 (b)) makes it possible to distinguish which electrode the water belongs to. Liquid water is mainly found at the cathode (horizontal channels) with water accumulation occurring primarily in the open channel areas and some water transported to the anode via the electroosmotic drag [5], [6], [24].…”

Section: Resultsmentioning

confidence: 99%

“…Given the classic linear model in (5), the maximum likelihood estimation (MLE) is the most effective method for estimating a [22]. By the AWGN assumption, this is equivalent to minimizing the following loss function [22]: min ,  a y Ha (6) which is the so-called least-squares estimation (LSE), where || || represents the Euclidean norm.…”

Section: Supplementary Materialsmentioning

confidence: 99%

Investigation of water generation and accumulation in polymer electrolyte fuel cells using hydro-electrochemical impedance imaging

Meyer

Liu

et al. 2019

Journal of Power Sources

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In-depth understanding of water management is essential for the optimization of the performance and durability of polymer electrolyte fuel cells (PEFCs). Neutron imaging of liquid water has proven to be a powerful diagnostic technique, but it cannot distinguish between 'legacy' water that has accumulated in the system over time and 'nascent' water recently generated by reaction. Here, a novel technique is introduced to investigate the spatially resolved water exchange characteristics inside PEFCs. Hydro-electrochemical impedance imaging (HECII) involves making a small AC-sinusoidal perturbation to a cell and measuring the consequential water generated, using neutron radiographs, associated with the stimulus frequency. Subsequently, a least-squares estimation (LSE) analysis is applied to derive the spatial amplitude ratio and phase shift. This technique provides a complementary view to conventional neutron imaging and provides information on the source and 'history' of water in the system. By selecting a suitable perturbation frequency, HECII can be used to achieve an alternative image 'contrast' and identify different features involved in the water dynamics of operational fuel cells.

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Visualization of liquid water in a lung-inspired flow-field based polymer electrolyte membrane fuel cell via neutron radiography

Cited by 94 publications

References 67 publications

Effect of compression on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Effect of compression on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Flow Field Patterns for Proton Exchange Membrane Fuel Cells

Investigation of water generation and accumulation in polymer electrolyte fuel cells using hydro-electrochemical impedance imaging

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