Kulkarni, Nivedita Narendra;
(2020)
Advancements in Polymer Electrolyte Fuel Cell Architecture and Performance using Electrochemical Modelling and Advanced Characterisations.
Doctoral thesis (Ph.D), UCL.
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Abstract
With the ever depleting traditional energy sources and increasing the carbon footprints, the new landscape of the renewable energy sources has evolved. With the versatility of required environmental conditions, topological locations, operating temperature, polymer electrolyte fuel cells (PEFCs) operating on hydrogen has been recognised as a prominent renewable energy technology. PEFCs offers the possibility of zero-emission and high power density electricity generation for a wide range of transport, portable, and stationary power applications. While technology continues to improve, there are still some challenges concerning durability, cost and performance. An improved understanding of the processes occurring within operational fuel cells and optimisation of the cell architecture will accelerate large-scale commercialization of PEFCs. The most powerful ways to understand and resolve these challenges is to understand the complex interplay of the internal workings of fuel cells and cell design and architecture and operating conditions. Hence, the current research aims to analyse the advancements in the fuel cell design and architecture using a thermo-structural multiphase electrochemical modelling and the advanced characterisation techniques Firstly, the intricate relationship between cell compression and the flow-field architecture is established by determining the morphological factors using X-ray computed tomography (CT) techniques. The results provide insight into the complex interplay of the morphological factors deciding fuel cell performance and durability. Also, this study provides insight into the extent at which the morphological factors decide water and thermal management of the fuel cell, which are key issues to tackle to broad-scale commercialisation of the technology. Further, the multiphase non-isothermal two-dimensional numerical model was developed. The two-dimensional current, temperature and liquid water saturation profiles reveal the in-situ gradients and their correlations with the voltage decay with respect to an increase in cell compression. Finally, the effects of cell compression on the PEFC water dynamics were analysed using in-plane and through-plane in-operando neutron radiography. Neutron radiography provides a detailed understanding of what constitutes the thickness of liquid water present in the operating fuel cell. The Neutron radiography results were also used to validate the numerical models developed. Finally, this work also investigates the effect of secondary flow-field on the dead-ended anode performance and highlights the importance of the manufacturing and assembly tolerances on fuel cell efficiency. Collectively; this project delineates the comprehensive suite of characterisation techniques and numerical modelling to resolve the PEFC challenges and achieve the cell optimisation and durability required for wide-scale commercialisation of the technology.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Advancements in Polymer Electrolyte Fuel Cell Architecture and Performance using Electrochemical Modelling and Advanced Characterisations |
| Event: | UCL |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| Keywords: | PEMFC, PEFC, Fuel cell, Neutron Imaging, modelling, X-ray CT, Tomography, Numerical analysis |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10108667 |
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