To Build Tomorrow s Fuel Cell Start with Tomorrow s

To Build Tomorrow’s Fuel Cell Start with Tomorrow’s Fuel Cell Engineer - Part II Eric M. Stuve, Per G. Reinhall, Joyce S. Cooper, Daniel T. Schwartz Departments of Chemical and Mechanical Engineering University of Washington http: //faculty. washington. edu/stuve/

Fuel Cell Design Experience • Fuel Cell Ugrad. Research (1991 -1996) – Single cell MEA-PEM development 10 • Fuel Cell Design Project (1996 -pres. ) Part I – Chem. E capstone design special project – ME capstone design & ugrad. research – EE & MSE students 50 114 9 • Fuel Cell Engineering (1998 -pres. ) Part II – Lecture / HW / project course – Technical support for F/C project – UW students 83 – Distance learning (EDGE) students 67 (Ballard, UTC-Fuel Cells, Honeywell, Ford, etc. )

Technical Goals • H 2/air fuel cell system, fully contained – 10 k. W (100 Amps @ 100 Volts) – Proton exchange membrane (PEM) system (80 °C) – Safe for student operation in public arena • Application: Prime mover for a locomotive – 18 in. gauge (approx. 1/3 scale) – Pull two passenger coaches – Use for Open House demonstrations • Other applications – SAE car, radio, H 0 scale train, etc.

MEA Preparation H O 2 2 Na. Cl Soak Clean + Na form Glycerol TBOH Me. OH Nafion soln. Sonicate Binder N 2 Dry DI H O 2 soak. H SO 2 4 100 C + H form Hot Press 130 C

Single Cell Data 1. 0 A: MEA w/ ID-FFP B: MEA w/ serp-FFP 0. 26 A/cm 2 at 0. 6 V E / V 0. 8 0. 6 0. 4 B A 0. 2 0 0 0. 2 0. 4 0. 6 j / A cm– 2 0. 8 1

Carl Ljungholm Matt Thompson Elisa Baris Chris Green Christy Silverman Greg Martin Jon Bumgardner

Small Test Stand Large Test Stand

Fuel Cell Engineering Course • UW & Distance Learning Students Worldwide • Course Outline: – Principles of electrochemical energy conversion – Single cells – Stack engineering – Systems engineering – Safety concerns

Distance Learning • Students sign up through UW-EDGE or NTU – EDGE for non-matriculated students (cheaper: $1, 467 per course) – NTU for M. S. students ($1, 950 per course) • Lectures – Streaming video (firewalls pose difficulties) – VHS or CD-ROM (delivery delay) • • Electronic course notes (pdf format; password protected) Homework submitted by e-mail or fax Exams proctored on-site and submitted by fax Instructor contact by e-mail or phone

Two Principles of the Course 1. Chemoelectricity* Chemistry must occur before energy flows F/C system like an entire chemical plant 2. Match Energy Source to Application Different cells for different applications Stationary / Vehicular / Portable Sometimes F/Cs won’t work (airplanes) *No, it’s not a cancer treatment!

Road Map for Quarter

Model of Springer, et al. Anode GDL PEM + H H 2 T=800 C H 2 H O drag 2 H O 2 1 Cathode GDL H O 2 H O diff 2 2 3 Make H 2 O 4 O 2 N 2 H O 2 43

Cell Diagnostics 1. 2. 3. 4. H 2/Air H 2/5. 2% O 2, N 2 H 2/O 2 H 2/13. 5% O 2, N 2 3/5 atm 3/2 atm 103

Stack Manifolding O 2 Manifold Stack H 2 Corner gasket O 2 H 2 O 121

Serpentine Flow Fields • One or more channels make multiple passes over MEA in serpentine configuration • Must specify number of parallel channels, nch = 1, 2, 3, etc. L W nch = 1 nch = 2 142

Heat Transfer in the FFP • Examine case for simple parallel FFP • Do 1 -D energy balance: z Ambient fluid Tb y x Solid Phase Ts(x) x Ta(x) or Tc(x) – gas temp. • Assumptions - T constant along y direction - Ts = temp. of solid phase = Ts (x) 146

Energy Balance for Solid Phase Ambient fluid Tb generation As = area of solid phase 149

Chilton-Coburn Analogy Mass Transfer Heat Transfer

Variations Along the MEA H 2 (–) x MEA dry hydrated E O 2 Suppose membrane hydration increases… l sm Em h => => sm Em h j (+) (at const. j) (at const. Eoc, E) (redist. of j, Em, h) Em h E E o

Results of Yi and Nguyen Cathode 3 0. 9 liq P / atm w vap M / M w, c 0 0 3 j / A cm – 2 <j> = 1. 1 0 0. 9 P / atm w Anode Base case: 0 0 x / cm 10 E = 0. 53 V; gas enters cathode dry <j> = 1. 1 (specified)

Flow & Control Systems Air H O Recov. 2 Purge Flow meter Turbocharger Stack F Motor H Memb H F Flow Resistor Heat Exch. Humid. (2 x) Ejector H 2 M Humid Level L T Flow control H O 2 Radiator

Anode Water Removal Air Turbocharger M Hum. F/C De-ionizing Filter (2 x) H 2 Cooling Water H O 2 Recycle Compressor Ballard Anode Water Removal System U. S. Pat. 5, 366, 818 Purge

Hydrogen Safety • Flame velocity very fast: 265 -325 cm/s - Compare with methane: 37 -45 cm/s - Large problem of backflashes H 2 flame Air - Backflash: motion of flame front backwards through system … this pulls outside air in and can cause internal explosions - To prevent backflash, gas must be supplied at a velocity greater than flame velocity • Small minimum flame diameter: 0. 6 mm - Min. diam. through which flame can pass - Compare with methane: 2 mm

HW: Nexa™ vs. Honda Determine: • Energy density of each generator • Power density of each generator • Thermodynamic efficiency of Honda generator (assumer Nexa is 41. 5%) • Discuss relative merits of each generator – Technical advantages and disadvantages – Marketing advantages and disadvantages – Neglect price for the moment

HW: Graphite vs. SS FFP 3. 0 mm MEA Junction of two graphite plates, each 1. 5 mm thick MEA Operating conditions: • 0. 65 V; 0. 6 A/cm 2; 80 °C • Cooling air enters at 40 °C • Max. DP of cooling air: 0. 3 atm SS allows 0. 5 mm wall thickness; cooling channels change, fuel/air channels remain the same Cathode/anode gas channels, 4 mm x 4 mm Cooling channel, 1 mm x 8 mm Graphite FFP For each FFP determine: • Cooling air flow rates • Cooling air h. t. c. • Overall h. t. c. • Exhaust temp. of cooling air • Parasitic load of cooling (assume 20% blower efficiency) • Compare performance; is one material superior to the other?

F/C Project: Seaglider

Lead-In Courses & Institutional Support CHEM E / ENVIR / M E / PHYS 341, 342 Energy and Environment I, II Interdisciplinary Fuel Cell Design Experience Outcomes CHEM E 445 (1998 -) Fuel Cell Engineering 83 UW students 67 Distance Learning students M E 430 Advanced Energy Conversion Capstone Design Project CHEM E 461 Electrochemical Engineering CHEM E 485 Process Design I M E 395 Introduction to Mechanical Design M E 415 Sustainability and Design for the Environment Institutional Support: CHEM E, ME, Co. E NSF-ECSEL CHEM E 497 (1996 -) Special Projects in Chemical Engineering Design 50 students M E Design & Research (1996 -) Mechanical Engineering Design 114 students Other Engineering Design EE – 6 students MSE – 3 students Graduate Program (Participating faculty: Adler, Bordia, Cooper, Jenkins, Kramlich, Malte, Overney, Reinhall, Schwartz, Stuve) Lifelong Learning Training to F/C industry Jobs in F/C Industry 16% of students in F/C industry UTC Fuel Cells Plug Power Idatek Honeywell CHEM E Core Curriculum F/C system for undergraduate lab; all students to study fuel cells External Support Dreyfus UTRC Ford UTC Fuel Cells Honeywell

What’s in the Future? • Chem. E Curriculum Development – – F/C is excellent example of integrating teaching & research Project work & course development spawn research ideas Specific F/C applications are examples of product design Improve project management and work skills of students • UW F/C Research Development – 10 faculty (Chem. E, ME, & MSE) working on PEM, SOFC, LCA, fundamentals – Pacific Northwest Energy Institute (Engineering, Business, Economics, Environmental Policy) • F/C Curriculum Development – Certificate program in F/C Engineering Intro, F/C Engr. , SOFC, Power Engr. , Adv. F/C Engr. – Available worldwide through EDGE

Acknowledgements • • All the students!!!! Russ Noe and the ME student shop Bruce Finlayson (Chem. E) Reiner Decher (A&A), Rich Christie (EE), Brian Flinn (MSE), Sossina Haile (MSE; now at Cal Tech) NSF-ECSEL for major funding Chem. E, ME Depts; College of Engineering Dreyfus Foundation Industrial Support – – – UTRC Ford UTC Fuel Cells Siemens Honeywell