AME 446/546

Fuel Cell Fundamentals and Design

Fall 2006

The University of Arizona

 

Instructor:   Dr. Peiwen (Perry) Li

                      E-mail:  peiwen@ame.arizona.edu

                      Course email:  Peiwen@D2L.arizona.edu ; course website:  http://www.d2l.arizona.edu

                      Office:  N725  Phone: 626-7789

                      Office hours:   M 9:00-10:00;  W 11:00-12:00

                      Please use e-mails to get me outside office hours.

 

Text: Course notes will be provided to cover material in class. Please check your course account (your net ID  **@D2L.arizona.edu ) to get class material before and after each class.

Recommended:        Fuel Cell Systems Explained, James Larminie and Andrew Dicks, 2nd Edition, John Wiley & Sons Inc.

Optional References: Transport Phenomena in Fuel Cells, Edited by B. Sunden and M. Faghri, WIT Press.                                      

Major Technical Journals for Reference:

                                   ASME J. Fuel Cell Science and Technology

                                   Journal of Power Sources

                                   Journal of The Electrochemical Society

 

Lecture:         T and Th   9:30am – 10:45 am;   Communication 214  ( U of A map location 5C)

                        

TA:                 To be decided 

 

Course Description:

      A fuel cell is an electrochemical device that directly converts the energy from a fuel into electrical power. It has the potential for highly efficient and environmentally friendly power. Much attention has been put recently to the development of fuel cell systems for power sources including portable, stationary, and automotive applications.

      The fundamental principles applied to fuel cells including the relevant electrochemistry, thermodynamics, and transport processes will be presented in this course. The primary focus will be on fundamental principles and processes in proton exchange membrane fuel cells, solid oxide fuel cells, and direct methanol fuel cells.  An introduction of fuel cell design and system integration will be presented, in which the analysis and optimization of flow channels, and current collection system will be discussed.  A survey of the cutting-edge issues including the future direction of fuel cell technology will also be conducted. Students will have an opportunity to directly operate a fuel cell as part of a hand-on laboratory experience.  A class project will also focus on the design of a fuel cell system for application chosen by students.

 

Course Objective: 

      This course is motivated from the strong need to prepare the next generation of multi-disciplinary engineers with a background in clean energy based on hydrogen and fuel cell science and technologies. The lectures are also designed to pique students’ interest in research and applying fuel cell power sources for various applications of electronic devices, aerospace and military missions, and stationary and distributed power generation. It is my goal to help each student who enrolled this class to achieve the following things upon satisfactory completion of this course:

(1)        Be able to apply fundamentals of electrochemistry, thermodynamics, fluid mechanics, and heat and mass transfer, as appropriate, to design or review designs of components of fuel cells and fuel cell systems.

(2)        Be able to describe the fundamentals of electrochemistry, electrochemical potentials, and perform calculations for various losses in fuel cells.

(3)        Be able to apply basic principles of reducing losses in fuel cells in their engineering career.

(4)        Graduate students will be able to perform in-sight research and modeling of the processes in fuel cells and advance the fuel cell science and technology.

 

Course Prerequisite:  Thermodynamics, fluid mechanics, heat transfer, or instructor permission

 

Course Grading Policy:

                    Homework:               35%  

                    Exams/Quizzes:        20%

                    Projects:                    30%

                    Lab session  ( subject to change upon building-up of Lab. )        10%

                    Class participation    5% 

 

Projects:

      There will be two general projects assigned during the course for all participating students. The general projects will require students to design fuel cell systems for particular application and perform calculations to predict operational performance. Graduate students will have one more project. This project will require students to perform analysis/design for the processes in fuel cells.

 

Attendance:

      It is assumed that those who regularly attend lectures will do better of homework, quizzes, and project and thus will achieve the goal of this course. Habitual late and non-attendance will forfeit the 5% class participation.

      All holidays or special events observed by organized religions will be honored for those students who show affiliation with that particular religion. Absences pre-approved by the UA Dean of Students (or Dean's designee) will be honored.

 

Policies Regarding Classroom Behavior:

      Please turn off cell phone.  No cell phone alarming and talk are allowed in class.

 

Students with Disabilities:

      If you anticipate issues related to the format or requirements of this course, please meet with me.  I would like us to discuss ways to ensure your full participation in the course.  If you determine that formal, disability-related accommodations are necessary, it is very important that you be registered with Disability Resources (621-3268; drc.arizona.edu) and notify me of your eligibility for reasonable accommodations.  We can then plan how best to coordinate your accommodations.

 

Homework Format:

      All homework should be in the following format unless it is an open-ended description, discussion question.

      Known: list given data and make a sketch if possible

      Find: list what to be found 

      Assumption and analysis: list assumptions and basic principles you will use to find unknowns

      Solution: Solve the problem, step-by-step, and always care about units.

      Comment: Make a comment as appropriate. All students, particularly graduate students are asked to take some time to dig a little deeper into the problem, for example, explain some interesting trend you notices in a particular problem.

 

 

Academic Dishonesty:

      Academic dishonesty will not be tolerated.  It is encouraged, however, to discuss problem solving techniques with classmate as long as each person does his/her own work.

 

Late Homework:

      Homework turned in after the date due will have 10 percent off the grade per day it is late.

 

The information contained in the course syllabus, other than the grade and absence policies, may be subject to change with reasonable advance notice, as deemed appropriate by the instructor.

 

 

 

Class Lectures ( Tentative Schedules for All Topics )

August 

Topics

22/8

Introduction

·      Course syllabus

·      How does a fuel cell look like?

·      What can it do?

·      What key components does a fuel cell have, and what is their function?

     --Photos and pictures of components for single fuel cells and fuel cell stacks

·     Important physical and chemical phenomena in fuel cells

·      What benefit do we have from using fuel cells?

     --the ideal efficiency curves for heat engines and fuel cells (SOFC),  hybrid power system

     --flexibility of power level, distributed power unit

·      What fuels are used in fuel cells? Are they available, and in what magnitude?

     --coal gasification concept

     --concept of storing renewable energy as hydrogen

·      What technical challenges do we have to meet in general? Graduate students may need to think about doing research work to elucidate some issues. 

24/8

Classification of fuel cells

·      Classification by the electrolyte used in a fuel cell

    AFC, PEMFC/DMFC, PAFC, MCFC

·      Operating temperatures

·      Fuel flexibility in SOFCs

·      Oxygen and air-breathing for oxygen  ( oxygen in air )

·      Geometries of fuel cells and fuel cell stacks

Thermodynamics (I)

·      Enthalpy of formation of substances ( introduce data sources )

     --look up enthalpy data from tables and calculate enthalpy  ( examples and calculation )

29/8

Thermodynamics (II)

·      Systematical enthalpy change of a reacting system

     --equations, calculation of enthalpy change  (examples and calculation )

·      Gibbs free energy of substances

     --look up data from tables and do calculations (examples)

31/8

Thermodynamics (III)

·      Systematical Gibbs free energy change of a reacting system ( examples)

     --perform calculation of Gibbs free energy change (examples)

     --perform calculation of Gibbs free energy change at different temperatures and pressures

 

 

 

 

September

Topics

5/9

Thermodynamics (IV)

·      Ideal efficiency of the energy conversion in fuel cells at different temperatures

     --high heating value and low heating value ( examples)

·      Energy budget in fuel cells

     --perform calculation of heat release in different types of fuel cells (examples)

     --power, heat due to entropy change, and internal ohmic heating

7/9

Electrochemistry (I)

·      Nernst equation for electromotive force and open circuit potential

     --pressure effect, temperature effect

--Optimization issue from the contradiction of Gibbs free energy decrease and ion conductivity increase, with temperatures in fuel cells

12/9

Electrochemistry (II)

·      Relation of the fuel consumption versus current output

    --PEM fuel cell, DMFC, and SOFC

·      Stoichiometric coefficients and utilization percentage of fuels and oxygen

·      Mass flow rate calculation for fuel and oxygen in single cell and fuel cell stack

14/9

Electrochemistry (III)

·     Total voltage and current when fuel cells are in parallel and serial connection.

·      Over-potentials and polarizations

·      Overview of the contributions of each polarizations

19/9

Electrochemistry  (PEMFCs- I)

·      PEMFC general (bipolar plate, backing layer/gas diffusion layer, membrane etc.)

·      Activation polarization

     --Tafel equation and exchange current density ( general for fuel cells)

     --calculation of activation polarization in PEMFCs

21/9

Electrochemistry  (PEMFCs- II)

·      Ionic conductivity of proton exchange membrane

     --catalyst for proton exchange membrane

     --Temperature and humidification effect

     --electro-osmotic drag effect

26/9

Electrochemistry  (PEMFCs- III)

·      Typical models for proton conductivity considering humidification

28/9

 Electrochemistry  (PEMFCs- IV)

·      Resistances from components and contact resistances

·      Internal resistances- analysis of the circuit of current collection in a PEMFC

 

 

 

 

 

 

 

 

 

 

 

 

 

 October

Topics

3/10

Mass Transfer Polarization in PEMFC

·     Diffusion of hydrogen and oxygen

    --Rate of mass transfer

5/10

Mass Transfer Polarization in PEMFC

·     Water flooding and dry out- water management

10/10

Design of PEMFC

·      Gas delivery and current collection bipolar plates design

    Flow uniformity consideration both single and stack level

    Sealing consideration at both single and stack levels

12/10

Optimization Design of PEMFC

·      Optimization of gas delivery and current collection/asymptotic power density

    --mass transfer consideration

    --Current collection consideration

    --minimal internal ohmic loss consideration  

17/10

Mid-exam

19/10

Other Issues for PEMFC

Psychrometrics of humid mixtures in PEMFC

Degradation and CO poisoning

24/10

Summary for PEMFC

Membrane from different maker

Bipolar plates from different maker

Diffusion layer from different maker

Survey of the state of the art power density, operating temperature, durability, total power etc.

Electrochemistry  (DMFC- I)

·      General issues (availability of methanol, high energy density)

·      DMFC operation scheme

     --catalyst loading for anode reaction and slow anode kinetics

     --carbon dioxide gas exclusion on anode side

26/10

Electrochemistry  (DMFC- II)

     --bipolar plate and flow channel design

     --operating temperature and concentration of methanol

     --methanol cross over

31/10

Electrochemistry  (DMFC- III)

     --water flooding and water management

Summary for DMFC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

November

Topics

2/11

Electrochemistry (SOFCs-I)

·      SOFC general ( high temperature, fuel flexibility, fast stat-up and hybrid system )

·      Current collection features and stacking up

·      Electromotive force ( hydrogen fuel only)

7/11

Electrochemistry (SOFCs-II)

·       Electromotive force ( with internal reforming )

·       Reaction equilibrium and kinetics

·      Ceramic/solid oxide electrolyte material

·      Ionic conductivity of solid oxide electrolyte, cathode

    --equations for ionic conductivity calculation ( homework for optimum temperature )

9/11

Electrochemistry (SOFCs-III)

·       Activation polarization

·     Resistances in electrodes

·      Contact resistances between components

14/11

Electrochemistry (SOFCs-IV)

·       Current collection analysis and asymptotic power density

16/11

Electrochemistry (SOFCs-V)

·     One dimensional modeling

21/11

Electrochemistry (SOFCs-VI)

·     Introduction for two and three dimensional modeling

23/11

Properties of gas mixtures for fuel cell species

 

Summary for SOFCs

28/11

Project presentation

30/11

Project presentation

 

 

 

 

December

Topics

     5/12

Project presentation

8/12-15/12

Final exam  ( no final exam)