Advanced Diagnostics Applied to a Self-Breathing Fuel Cell

Obeisun, Oluwamayowa A.; Meyer, Quentin; Robinson, James B.; Gibbs, C. F.; Kucernak, Anthony; Shearing, Paul R.; Brett, Dan J. L.

doi:10.1149/06127.0249ecst

Cited by 12 publications

(15 citation statements)

References 18 publications

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“…Thermocouples can provide a crude measure of temperature inside fuel cells [15][16][17][18], but cannot provide high spatial resolution, and as they need to be inserted inside the fuel cell, this often requires design modifications which may affect reactant flow and fuel cell performance. Infrared thermal imaging can provide very high spatial and temperature resolution [19][20][21][22][23][24], but requires use of modified fuel cells with an infrared transparent window, and/or cells with open channels (such as open-cathode fuel cells [25][26][27][28]) or can only image the outer surface of a cell or stack [29,30]. Combined temperature and current mapping studies allow the impact and interactions of these two parameters on the overall performance to be assessed [17,20,[31][32][33].…”

Section: Current and Temperature Mapping In Fuel Cellsmentioning

confidence: 99%

Nitrogen Blanketing and Hydrogen Starvation in Dead-Ended-Anode Polymer Electrolyte Fuel Cells Revealed by Hydro-Electro-Thermal Analysis

Meyer

Ashton

Torija

et al. 2016

Electrochimica Acta

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Dead-ended anode operation has a number of practical advantages that simplify system complexity and lower cost for polymer electrolyte fuel cells. However, deadended mode leads to performance loss over time which can only be reversed by performing intermittent purge events. This work applies a combined hydro-electrothermal analysis to an air-cooled open-cathode fuel cell, presenting experimental functional maps of water distribution, current density and temperature. This approach has allowed the identification of a 'nitrogen blanketing' effect due to nitrogen crossover from the cathode and a 'bypass' effect where a peripheral gap between the gasket and the GDL offers a hydrogen flow 'short circuit' to the border of the electrode. A consequence of high local current density at the margin of the electrode, and resulting high temperatures, may impact the lifetime of the cell in dead-end mode. KeywordsDead-ended anode; bypass effect; neutron imaging; nitrogen blanketing; current and temperature mapping. 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. Dead-ended anode operation enables significant design simplification, with the replacement of humidifiers, and flow controllers by pressure regulators [1]. However, it causes 3 reversible performance decay, and intermittent purging of the anode chamber is required to sustain effective operation. Greater insight into the mechanism of fuel cell operation during dead-ended mode is required in order to optimise the purging programme and ensure that irreversible degradation does not result. In-situ diagnostic techniques provide one of the most effective ways of studying the performance of fuel cells; combined mapping of current density, temperature and water distribution is applied here to give an unprecedented level of understanding into dead-ended fuel cell operation. Current and temperature mapping in fuel cellsInitiated by Cleghorn et al. 4 Combined temperature and current mapping studies allow the impact and interactions of these two parameters on the overall performance to be assessed [17,20,[31][32][33]. However, capturing the water content may provide insights on how the temperature and current density fluctuate, and therefore should ideally be measured at unison. Neutron imaging in fuel cellsNeutron imaging can identify water in the in-plane orientation (with the membrane plane parallel to the beam) and through-plane orientation (with the membrane plane perpendicular to the beam), enabling differentiation of water content in the cathode and the anode [34][35][36] Dead-ended anode operations in an air-cooled open cathode fuel cell.Dead-ended anode operation is a common mode for operating fuel cells as it can simplify the fuel cell system, potentially avoiding flow meters, humidifiers, and drastically reducing hydrogen losses (slippage). It employs a single pressure regulator befor...

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Section: Current and Temperature Mapping In Fuel Cellsmentioning

confidence: 99%

Nitrogen Blanketing and Hydrogen Starvation in Dead-Ended-Anode Polymer Electrolyte Fuel Cells Revealed by Hydro-Electro-Thermal Analysis

Meyer

Ashton

Torija

et al. 2016

Electrochimica Acta

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“…otherwise confined to open-cathode fuel cells [23][24][25] or the outer surface of a cell or stack [26,27].…”

Section: Current and Temperature Mapping In Fuel Cellsmentioning

confidence: 99%

The Hydro-electro-thermal Performance of Air-cooled, Open-cathode Polymer Electrolyte Fuel Cells: Combined Localised Current Density, Temperature and Water Mapping

Meyer

Ashton

Jervis

et al. 2015

Electrochimica Acta

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In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, a novel metrology approach is reported that combines current and temperature mapping with water visualisation using neutron radiography.The approach enables a hydro-electro-thermal performance map to be generated that is applied to an air-cooled, open-cathode polymer electrolyte fuel cell. This type of fuel cell exhibits a particularly interesting coupled relationship between water, current and heat, as the air supply has the due role of cooling the stack as well as providing the cathode reactant feed via a single source. It is found that water predominantly accumulates under the cooling channels (thickness of 70-100 µm under the cooling channels and 5-25 µm in the active channels at 0.5 A cm KeywordsAir-cooled open-cathode polymer electrolyte fuel cell; water mapping; neutron imaging; temperature mapping; current mapping.

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“…This mode of operation can also be used as a diagnostic-identifying areas of high or low electrochemical activity, thus elucidating vital information in the design and optimisation of systems. Air breathing PEMFCs were examined by Obeisun et al [39] who looked at the temperature distributions, shown in Figure 2, associated with the passive fuelling strategy employed by these devices. An increased operating current was seen to result in increased surface temperatures, with inhomogeneous distributions being imposed on the device by the housing in which it was contained.…”

Section: Single Frame Imagingmentioning

confidence: 99%

“…The effect of clamping pressure was also observed to have an impact on the temperature distribution; with lower clamping pressures in the center of the cell resulting in a lower temperature, this was attributed to poor electrical contact. Images showing the effect of the opening ratio (i.e., the area of electrode exposed to the atmosphere) of an air breathing PEMFC obtained by Obeisun et al [39]. Heterogeneous temperature distribution is clearly visible on the cell due to non-uniform clamping forces and the flow configuration in the system.…”

Section: Single Frame Imagingmentioning

confidence: 99%

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Thermal Imaging of Electrochemical Power Systems: A Review

2016

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The performance and durability of electrochemical power systems are determined by a complex interdependency of many complex and interrelated factors, temperature and heat transfer being particularly important. This has led to an increasing interest in the use of thermal imaging to understand both the fundamental phenomena and effects of operation on the temperature distribution and dynamics in these systems. This review describes the application thermal imaging and related techniques to the study of electrochemical power systems with the primary focus on fuel cells and batteries. Potential opportunities and directions for future research are also highlighted, indicating the wide scope for further insights to be gleaned using infrared thermal imaging techniques.

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Advanced Diagnostics Applied to a Self-Breathing Fuel Cell

Cited by 12 publications

References 18 publications

Nitrogen Blanketing and Hydrogen Starvation in Dead-Ended-Anode Polymer Electrolyte Fuel Cells Revealed by Hydro-Electro-Thermal Analysis

Nitrogen Blanketing and Hydrogen Starvation in Dead-Ended-Anode Polymer Electrolyte Fuel Cells Revealed by Hydro-Electro-Thermal Analysis

The Hydro-electro-thermal Performance of Air-cooled, Open-cathode Polymer Electrolyte Fuel Cells: Combined Localised Current Density, Temperature and Water Mapping

Thermal Imaging of Electrochemical Power Systems: A Review

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