UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Advanced Metrology for the Development of Nature-Inspired Polymer Electrolyte Fuel Cells

Bethapudi, Viswanath Sasank; (2021) Advanced Metrology for the Development of Nature-Inspired Polymer Electrolyte Fuel Cells. Doctoral thesis (Ph.D), UCL (University College London).

[thumbnail of PhD Thesis_Viswanath Sasank Bethapudi_Final Submission.pdf] Text
PhD Thesis_Viswanath Sasank Bethapudi_Final Submission.pdf
Access restricted to UCL open access staff until 1 April 2022.

Download (9MB)

Abstract

The cathode flow-field is an important component in polymer electrolyte membrane fuel cells (PEMFCs) that influences the cell’s performance significantly. An effective cathodic flow-field design is necessary for efficient transport and removal of reactants and products from its respective electrode. Fractal flow-fields, inspired by the flow mechanism of air inside the lungs, are identified to provide homogeneous, scalable and uniform distribution of reactants to polymer PEMFC electrodes. In this thesis, the design and development of lung-inspired fractal flow-fields, developed from layered planar printed circuit board (PCB) plates, is presented for cathodic reactant transport. The PCB-based approach makes the fractal flow-field cost-effective, easy to manufacture, scalable and lightweight, compared to laser sintered stainless steel fractal flow-fields, developed in previous work in the Centre for Nature-Inspired Engineering. Furthermore, advanced metrology techniques are utilised to characterise the lung-inspired fuel cells with a view to optimise their design and performance. Uniformity and alignment between individual PCB layers producing a fractal hierarchy of flow channels have been characterised using X-ray computed tomography (X-ray CT). Performance polarisations, current-voltage degradations and cell temperatures indicate that fractal PEMFCs perform better than conventional, single-serpentine PEMFCs. Standard electrochemical characterisations confirm the basis for the observed performance enhancement when using a fractal flow-field. Acoustic emission (AE) analysis, a first of its kind non-invasive and non-destructive hydration diagnostics tool, is utilised as a water management technique that identifies the presence of liquid water in flow channels and correlates its removal and generation with the level of cell performance. In addition, electro-thermal mapping, which reflects the surface distribution of current and temperature generated inside the cell, is performed to evaluate the influence of reactant and water distribution conditions inside the cells on its localised and overall cell performance.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Advanced Metrology for the Development of Nature-Inspired Polymer Electrolyte Fuel Cells
Event: UCL (UNIVERSITY COLLEGE LONDON)
Language: English
Additional information: Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/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.
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
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/10124044
Downloads since deposit
3Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item