Author: Zahra Tayarani Yoosefabadi
Publisher:
ISBN:
Category :
Languages : en
Pages : 179
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Book Description
Polymer electrolyte fuel cells (PEFCs), as promising clean energy power sources, are potential substitutes not only for stationary power generation but also for mobile applications specifically in transportation due to their high power density and performance as well as lack of pollutants. PEFC vehicles are at the dawn of commercialization, but still, cost, performance, and durability of current PEFCs need to be further improved to facilitate vast market integration especially under high current density conditions. Pursuant to this goal, comprehensive multidisciplinary understanding of multiphase transport of mass, heat, and electricity in the PEFC constituents including the gas diffusion layer (GDL), as the centerpiece of this thesis, will help to make progress towards material optimization and subsequently fuel cell performance improvements. The GDL transport capability is determined by its effective transport properties which are strongly dependent on its morphological, microstructural, and physical characteristics. Therefore, accurate knowledge regarding the correlation between the GDL microstructure and its transport properties is essential for improving the performance and durability of PEFCs as well as for material optimization, fuel cell design, and prototyping in the area of fuel cell development and manufacturing. In this context, this thesis aims to develop a fast and cost-effective design tool for GDL microstructural modeling and transport properties simulation. Given the limitations of experimental, analytical, and tomographic techniques, stochastic microstructural model development to retrieve the heterogeneous GDL microstructure is a more reliable and flexible tool for GDL material design and prototyping assignments to reduce cost and time of the design cycle. Inspired by the randomness of the GDL porous media structure and its fabrication process, the GDL microstructure is virtually reconstructed as a collection of stochastic processes to provide a robust representation of the structure. The technique of stochastic microstructural reconstruction relies on statistical correlation functions which describe the probabilities of the porous media constituents' distribution and aim to encompass all the details of the porous media. The obtained 3D digitized realizations of the stochastic model are then used as a domain for numerical computation of transport properties. In this thesis, a unique stochastic GDL microstructural modeling framework inspired by manufacturing information and characterization data is developed in which all GDL substrate and MPL components are resolved, and thoroughly validated with literature and measured data for a variety of MPL-coated GDLs. The effects of PTFE loading and liquid water saturation on the GDL substrate anisotropic transport properties for both gas and liquid phases are found to be highly coupled and are therefore simulated and analyzed jointly. Furthermore, a parametric study is conducted to investigate the effect of MPL pore morphology composition on the MPL and MPL-coated GDL transport properties. The validated stochastic design tool can be used as a fast and accurate framework for reconstructing GDL porous materials and understanding the correlation between the GDL morphology and transport properties. This paves the way for development of improved GDL materials with desired transport properties in modern PEFCs.
Author: Jasna Jankovic
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110623609
Category : Technology & Engineering
Languages : en
Pages : 555
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Book Description
This book is a comprehensive introduction to the rapidly developing field of modeling and characterization of PEM fuel cells. It focuses on i) fuel cell performance modeling and performance characterization applicable from single cells to stacks, ii) fundamental and advanced techniques for structural and compositional characterization of fuel cell components and iii) electrocatalyst design. Written by experts in this field, this book is an invaluable tool for graduate students and professionals.
Author: Xianguo Li
Publisher: CRC Press
ISBN: 113520179X
Category : Science
Languages : en
Pages : 465
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Book Description
The book is engineering oriented and covers a large variety of topics ranging from fundamental principles to performance evaluation and applications. It is written systematically and completely on the subject with a summary of state-of-the-art fuel cell technology, filling the need for a timely resource. This is a unique book serving academic researchers, engineers, as well as people working in the fuel cell industry. It is also of substantial interest to students, engineers, and scientists in mechanical engineering, chemistry and chemical engineering, electrochemistry, materials science and engineering, power generation and propulsion systems, and automobile engineering.
Author: Christoph Hartnig
Publisher: Elsevier
ISBN: 0857095471
Category : Technology & Engineering
Languages : en
Pages : 437
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Book Description
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
Author: Eric Wargo
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 322
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Book Description
The polymer electrolyte fuel cell (PEFC) is an electrochemical device which holds great promise as an alternative power source for use in a wide range of applications. However, improvements in cell performance are necessary for the commercialization of PEFCs. Recently, significant research effort has been placed on understanding the influence of the internal structure (i.e., microstructure) of fuel cell materials on the transport of water and reactant gases in PEFC systems. One component of interest is the porous diffusion media (DM), which has been shown to be vital for achieving necessary water management to maintain efficient fuel cell operation. However, current modeling efforts rely primarily on bulk correlations or idealized/randomly selected structures for these porous materials, which may misrepresent the true morphology of the DM and potentially fail to accurately capture the related effects on transport within this component. The objective of this dissertation work is to establish a framework which combines recent advances in 3-D microstructure quantification and pore-scale analysis to evaluate the structure and related transport characteristics of fuel cell DM. The presented framework includes the following features: i) the microstructures of the materials of interest are quantified rigorously in 3-D; ii) small representative volume elements (RVEs) are selected which capture the important features of the measured microstructure datasets to within high accuracy, for reliable and computationally efficient modeling of transport behavior; and iii) a suite of microstructure analysis tools is developed to determine several difficult-to-measure key structure-related transport properties. Using this approach, an in-depth understanding of the structure-related transport characteristics of a fuel cell DM sample is achieved.
Author: Thandavarayan Maiyalagan
Publisher: John Wiley & Sons
ISBN: 3527803890
Category : Technology & Engineering
Languages : en
Pages : 618
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Book Description
Meeting the need for a text on solutions to conditions which have so far been a drawback for this important and trend-setting technology, this monograph places special emphasis on novel, alternative catalysts of low temperature fuel cells. Comprehensive in its coverage, the text discusses not only the electrochemical, mechanistic, and material scientific background, but also provides extensive chapters on the design and fabrication of electrocatalysts. A valuable resource aimed at multidisciplinary audiences in the fields of academia and industry.
Author: Matthew M. Mench
Publisher: Academic Press
ISBN: 0123869560
Category : Technology & Engineering
Languages : en
Pages : 473
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Book Description
For full market implementation of PEM fuel cells to become a reality, two main limiting technical issues must be overcome-cost and durability. This cutting-edge volume directly addresses the state-of-the-art advances in durability within every fuel cell stack component. Designed to be relevant to the professional community in addition to researchers, this book will serve as a valuable reference featuring topics covered nowhere else and a one-stop-shop to create a solid platform for understanding this important area of development. The reference covers aspects of durability in the entire fuel cell stack. Each chapter also includes vision of pathways forward and an explanation of the tools needed to continue along the path toward commercialization. - Features expert insights from contributing authors who are key industrial and academic leaders in the field - Includes coverage of two key topics in the field- Testing and Protocol for Durability, and Computational Modeling Aspects of PEFC Durability- which are newly emerging, pivotally important subjects not systematically covered anywhere else - Undertakes aspects of durability across the entire fuel stack, from membranes to bipolar plates
Author: Mohammadreza Fazeli
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Ugur Pasaogullari
Publisher: Springer Science & Business Media
ISBN: 0387980687
Category : Science
Languages : en
Pages : 412
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Book Description
This volume, presented by leading experts in the field, covers the latest advances in diagnostics and modeling of polymer electrolyte fuel cells, from understanding catalyst layer durability to start-up under freezing conditions.
Author: Michael Gerald George
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Characterization of gas diffusion layers (GDLs) for polymer electrolyte membrane (PEM) fuel cells informs modeling studies and the manufacturers of next generation fuel cell materials. Identifying the physical properties related to the primary functions of the modern GDL (thermal, electrical, and mass transport) is necessary for understanding the impact of GDL design choices. X-ray micro-computed tomographic reconstructions of GDLs were studied to isolate GDL surface morphologies. Surface roughness was measured for a wide variety of samples and a sensitivity study highlighted the scale-dependence of surface roughness measurements. Furthermore, a spatially resolved distribution map of polytetrafluoroethylene (PTFE) in the microporous layer (MPL), critical for water management and mass transport, was identified and the existence of PTFE agglomerations was highlighted. Finally, the impact of accelerated degradation on GDL wettability and water transport increases in liquid water accumulation and oxygen mass transport resistance were quantified as a result of accelerated GDL degradation.
