PREFACE TO THE SECOND EDITION

PEM Fuel Cells: Theory and Practice was written seven years ago as a resultof my desire to share with younger generations of engineers and scientistsknowledge gained from my experience at the forefront of fuel cellresearch and development. Most of what I have learned about fuel cells Igathered from hands-on experience in designing, building, testing, andevaluating fuel cell stacks and systems and making them work in practicalapplications. Over the last seven years I have continued to conduct R&Din PEM fuel cells, yet I only reluctantly agreed to prepare this secondedition, as I was afraid that the rapidly developing nature of the fieldwould have rendered the book very outdated. However, in goingthrough the original manuscript I realized that although it is indisputablethat fuel cell technology has made tremendous progress in the last sevenyears, at least the basics of PEM fuel cell engineering and operationcovered in the book had not changed so much. That said, there werenew materials, new designs, new diagnostic methods, and valuablefeedback from years of field experience that needed to be added. Asa result, we have developed a much more nuanced understanding of theprocesses impacting choice of materials, construction, performance, andlongevity.

In recognition of the multifaceted character of the field’s evolution, thechapter on diagnostics has been rewritten by an expert in this particular area,Dr. Haijiang Wang from the Institute for Fuel Cell Innovation, NationalResearch Council Canada, Vancouver, British Columbia.

Realizing that fuel cell durability is of crucial importance, I decided to adda new chapter on PEM fuel cell durability, and I invited another expertpractitioner, Dr. Michael Perry, fromUnited Technologies Research Center,East Hartford, Connecticut, to contribute it. I am taking this opportunity tothank Dr. Wang and Dr. Perry for their valuable contributions.

Advances in new materials, particularly membranes and catalysts, havebeen addressed in the chapter on main cell components, materials properties,and processes.

In the chapter on fuel cell operating conditions, I have added insightsfrom my colleague Torsten Berning from Aalborg University, Denmark,about dew-point temperature of exhaust gases as a criterion for selection ofoperating conditions. My thanks are due him as well.

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During the last seven years, numerous papers on fuel cell modeling havebeen published, covering various domains and physical phenomena as wellas many new modeling methods and techniques. These models, inconjunction with improved diagnostic techniques, have provided betterunderstanding of the intricacies of fuel cell operation, particularly around therole of water in fuel cell operation. The chapter on fuel cell modeling in thefirst edition of this book was organized by first presenting the basic gov-erning equations describing conservation of mass, momentum, energy,species, and charge, then by giving their application in modeling examplesfor various domains, that is, across the membrane, above the channel andland, along the channel, and in three dimensions. I decided to keep the sameorganization and examples in this revised chapter, since they cover thefundamentals effectively. However, I added an example on modeling watertransport in the gas diffusion layer through a pore network model asa representative of the new models that elucidate peculiar water behavior inporous fuel cell structures.

Diagrams, photos, and tables have been updated wherever applicablethroughout the book but particularly in the chapter on fuel cell applications.Tables from the U.S. DOE Hydrogen and Fuel Cell Program, showingcurrent status and technical targets for various applications, have been added.All other chapters have been edited once again and corrected or updatedwhere necessary.

I would like to thank my students and post-docs at UNIDO-ICHET,the FESB University of Split, and the University of Wyoming who havepointed out some errors, typos, and unclear statements to help me improveon the content of the first edition.

I use this book as a text to teach a full-semester fuel cell engineeringcourse as well as numerous short courses. In doing so, I have preparedthousands of slides organized to follow the book over the years. These slideswill be made available on the book’s Website to those who want to use thebook to teach a fuel cell course. My advice is to use these slides as a backbonefor lectures and to spice them up with the newest developments in fuel celltechnology as they emerge. At the end of each chapter there are numericalproblems that may be assigned as homework. Solutions will also be posted ina password-protected instructor section of the book’s Website. In addition,each chapter has a quiz at the end. I have found these quizzes very useful, notonly to evaluate students’ progress but also to evaluate my effectiveness asa teacher. After each quiz I perform a statistical analysis to identify the

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questions that most of the students have not answered correctly. I thenrevisit that part of the lecture.

It is my hope that the publication of this second edition of the book willincrease opportunities for interactively sharing the experiences of instructorsand students as well as the scientists and engineers all over the world who areinvolved in making better and more affordable fuel cells. This book isdedicated to all of them.

Finally, I would like to thank Jill Leonard and Tiffany Gasbarrini atElsevier for their guidance, support, encouragement, and especially theirpatience throughout the process of preparing this second edition.

Frano BarbirFESB University of Split, Split, Croatia, June 2012