This book examines the characteristics of Proton Exchange Membrane (PEM) Fuel Cells with a focus on deriving realistic finite element models. The book also explains in detail how to set up measuring systems, data analysis, and PEM Fuel Cells’ static and dynamic characteristics. Covered in detail are design and operation principles such as polarization phenomenon, thermodynamic analysis, and overall voltage; failure modes and mechanisms such as permanent faults, membrane degradation, and water management; and modelling and numerical simulation including semi-empirical, one-dimensional, two-dimensional, and three-dimensional models. It is appropriate for graduate students, researchers, and engineers who work with the design and reliability of hydrogen fuel cells, in particular proton exchange membrane fuel cells.

This thesis deals to optimize the performance of PEMFC fuel cells, through the development of new flow-field plate designs. Tools such as water balance and electrochemical noise analysis have been used to diagnose water management within a PEMFC single cell. Optimal management of the water transport enables an increase of the performance and durability of fuel cells. Water balance method was used to measure and frame the value of the effective water diffusion coefficient within the membranes of fuel cells. New flow-flied plate geometries have been developed and characterized by conventional polarization curve and pressure measurements. The electrochemical noise technique was used to detect phenomena related to the behavior of water during fuel cell operation for each geometry developed. Electrochemical noise measurements have been associated with source mechanisms through an experimental approach and an appropriate signal processing based on frequency and time analysis. The descriptors obtained by time and frequency analysis shows that it possible to obtain the signature in normal operation of a fuel cell using a classical serpentine. This signature was compared to the new developed designs allowing to characterize the influence of these new geometries on the water transport. Finally, to complete the experimental approach carried out on the water diffusion coefficient within the membranes of PEMFC fuel cells, a model based on polarization curve, considering this coefficient, was developed and compared to the experimental curves of performances. In perspective, the impact of the new developed geometries has been extended in a stack utilization and a prognosis model based on artificial neural networks has been proposed.

While PEM fuel cells are highly efficient, environmentally friendly sources of power, their durability hinders the commercialization of this technology. With contributions from international scientists active in PEM fuel cell research, PEM Fuel Cell Durability Handbook, Two-Volume Set provides a comprehensive source of state-of-the-art research in

Polymer electrolyte membrane (PEM) fuel cell stack was analyzed from a mechanical point of view with the help of measurements and simulations in this study. The deflection of the fuel cell stack was measured with the help of the experimental set-up under operating conditions. The effects of cell operating parameters and cyclic conditions on the mechanical properties of the fuel cell stack were investigated. In order to extend the mechanical analysis of the fuel cells, two computational models were established containing the geometrical features in detail. A large-scale fuel cell stack model was built for the thermomechanical analysis. The second model was built on a cross-section geometry for the electrochemical analysis including fluid dynamics. The internal stress distribution and buckling of fuel cell stack were examined. The influence of the mechanical compression on the cell performance and squeezing of the gas diffusion layers are investigated. A design procedure is developed for fuel cell stack regarding the durability and performance from a mechanical point of view.

PEM Fuel Cell Testing and Diagnosis covers the recent advances in PEM (proton exchange membrane) fuel cell systems, focusing on instruments and techniques for testing and diagnosis, and the application of diagnostic techniques in practical tests and operation. This book is a unique source of electrochemical techniques for researchers, scientists and engineers working in the area of fuel cells. Proton exchange membrane fuel cells are currently considered the most promising clean energy-converting devices for stationary, transportation, and micro-power applications due to their high energy density, high efficiency, and environmental friendliness. To advance research and development of this emerging technology, testing and diagnosis are an essential combined step. This book aids those efforts, addressing effects of humidity, temperature and pressure on fuel cells, degradation and failure analysis, and design and assembly of MEAs, single cells and stacks. - Provides fundamental and theoretical principles for PEM fuel cell testing and diagnosis. - Comprehensive source for selecting techniques, experimental designs and data analysis - Analyzes PEM fuel cell degradation and failure mechanisms, and suggests failure mitigation strategies - Provides principles for selecting PEM fuel cell key materials to improve durability

Polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) technology are promising forms of low-temperature electrochemical power conversion technologies that operate on hydrogen and methanol respectively. Featuring high electrical efficiency and low operational emissions, they have attracted intense worldwide commercialization research and development efforts. These R&D efforts include a major drive towards improving materials performance, fuel cell operation and durability. In situ characterization is essential to improving performance and extending operational lifetime through providing information necessary to understand how fuel cell materials perform under operational loads.This two volume set reviews the fundamentals, performance, and in situ characterization of PEMFCs and DMFCs. Volume 1 covers the fundamental science and engineering of these low temperature fuel cells, focusing on understanding and improving performance and operation. Part one reviews systems fundamentals, ranging from fuels and fuel processing, to the development of membrane and catalyst materials and technology, and gas diffusion media and flowfields, as well as life cycle aspects and modelling approaches. Part two details performance issues relevant to fuel cell operation and durability, such as catalyst ageing, materials degradation and durability testing, and goes on to review advanced transport simulation approaches, degradation modelling and experimental monitoring techniques.With its international team of expert contributors, Polymer electrolyte membrane and direct methanol fuel cell technology Volumes 1 & 2 is an invaluable reference for low temperature fuel cell designers and manufacturers, as well as materials science and electrochemistry researchers and academics. - Covers the fundamental science and engineering of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs), focusing on understanding and improving performance and operation - Reviews systems fundamentals, ranging from fuels and fuel processing, to the development of membrane and catalyst materials and technology, and gas diffusion media and flowfields, as well as life cycle aspects and modelling approaches - Details performance issues relevant to fuel cell operation and durability, such as catalyst ageing, materials degradation and durability testing, and reviews advanced transport simulation approaches, degradation modelling and experimental monitoring techniques

PEM Fuel Cell Diagnostic Tools presents various tools for diagnosing PEM fuel cells and stacks, including in situ and ex situ diagnostic tools, electrochemical techniques, and physical/chemical methods. The text outlines the principles, experimental implementation, data processing, and application of each technique, along with its capabilities and weaknesses. The book covers many diagnostics employed in the characterization and determination of fuel cell performance. It discusses commonly used conventional tools, such as cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and transmission electron microscopy. It also examines special tools developed specifically for PEM fuel cells, including transparent cells, cathode discharge, and current mapping, as well as recent advanced tools for diagnosis, such as magnetic resonance imaging and atomic force microscopy. For clarity, the book splits these diagnostic methodologies into two parts—in situ and ex situ. To better understand the tools, PEM fuel cell testing is also discussed. Each self-contained chapter provides cross-references to other chapters. Written by international scientists active in PEM fuel cell research, this volume incorporates state-of-the-art technical advances in PEM fuel cell diagnosis. The diagnostic tools presented help readers to understand the physical and chemical phenomena involved in PEM fuel cells.

This book covers a significant number of R&D projects, performed mostly after 2000, devoted to the understanding and prevention of performance degradation processes in polymer electrolyte fuel cells (PEFCs). The extent and severity of performance degradation processes in PEFCs were recognized rather gradually. Indeed, the recognition overlapped with a significant number of industrial dem- strations of fuel cell powered vehicles, which would suggest a degree of technology maturity beyond the resaolution of fundamental failure mechanisms. An intriguing question, therefore, is why has there been this apparent delay in addressing fun- mental performance stability requirements. The apparent answer is that testing of the power system under fully realistic operation conditions was one prerequisite for revealing the nature and extent of some key modes of PEFC stack failure. Such modes of failure were not exposed to a similar degree, or not at all, in earlier tests of PEFC stacks which were not performed under fully relevant conditions, parti- larly such tests which did not include multiple on–off and/or high power–low power cycles typical for transportation and mobile power applications of PEFCs. Long-term testing of PEFCs reported in the early 1990s by both Los Alamos National Laboratory and Ballard Power was performed under conditions of c- stant cell voltage, typically near the maximum power point of the PEFC.