1. Design of Fuel Cell Membrane Test Stand for Advanced Fuel Cell Research
Rebekah Achtenberg, Brandon Darr, Luke Roobol
Western Michigan University
College of Engineering and Applied Sciences
Mechanical and Aeronautical Engineering Department
ME 1004-07
April 20, 2010

2. Outline of Presentation
Scope of the Project
Fuel Cell Background
Design
Sensors
Instrumentation
Experimental Methods
Evaluation Methods
3. Scope of the Project
A fuel cell membrane test stand was designed and fabricated to evaluate solid polymer electrolytes at the reactant-catalyst-electrolyte interface
Three new membranes from the Institute of Macromolecular Chemistry in Kiev, Ukraine were tested and analyzed
C-40
N-172
229
Characterizations were made of the membranes and gas diffusion electrodes.
The membranes were compared to the Nafion 117 membrane.
4. What is a Fuel Cell
A Fuel Cellworks by combining Hydrogen and Oxygen Gas to produce electricity and the only byproduct is water and heat.
Fuel cells have also been called Gas Batteries
The reaction withina Fuel Cell the opposite of electrolysis.
Fuel Cells are classified by the type of electrolyte utilized
There were two types of Fuel Cells that were tested
Proton Exchange (PEM acid)
Hydroxyl Exchange (Alkaline Fuel Cell)
5. Types of Fuel Cells
PEM Fuel Cell
Alkaline Fuel Cell
Proton Exchange Membrane
Polymer Exchange Membrane
Hydroxyl Exchange Membrane
Anion Exchange Membrane
Anode
Anode
Cathode
Cathode
6. Fuel Cell Membrane Test Stand
A Test Stand was fabricated by modifying an existing fuel cell manufactured by Parker Hannifin TekStakTM Fuel Cell.
A fuel cell membrane test stand was designed to evaluate solid polymer electrolytes.
The test stand allows for the measurement at the reactant-catalyst-electrolyte interface.
Temperature
Pressure
Humidity
Oxygen concentration
7. Parts of a Fuel Cell
8. Material Selection
Gas Diffusion Electrode
Carbon Cloth
Porous and Flexible
Platinum Catalyst Layer
Pt is the most reactive and expensive catalyst
Robust design (4 mg/cm2)
To isolate membrane performance
Gaskets
20 mil Silicone Rubber
30% compression
9. Sensors
Temperature
E type thermocouple
Humidity
Honeywell relative humidity sensor
Compact size
Low Cost
Pressure
Absolute Gas Pressure Sensor
3-36 psi range
Temperature Compensated
Easy Integration
5 V supply voltage
Oxygen
Advanced Micro Instruments Model 60 Oxygen Probe
electrochemical sensor type
0-25% oxygen range
10. Integration of Pressure and Oxygen Sensors
11. Design
Flow plate
Serpentine Pattern
High channel velocity
Good water removal
High Performance
Graphite
The flow plate was redesigned to accommodate the sensors
Humidity Sensor
Needle
Oxygen Sensor
Pressure Sensor
12. Design
13. Instrumentation
Data Acquisition System
DAQ card
NI-6211
LabVIEW
Graphical programming environment
External Power Supply
For the oxygen sensor
14. Instrumentation Setup
External Power Supply
Electronic Fuel Cell Load Machine
Oxygen Sensor
DAQ Card
Humidity Sensor
Pressure Sensor
Thermocouples
Pressure SensorWires
15. Instrumentation
16. Instrumentation
17. Hydrogen and Air Supply Setup
18. Characterizations
Characterizations of the membrane materials and the gas diffusion electrodes were completed.
Optical Microscopy
Basic morphology of membranes and GDLs
Scanning Electron Microscopy (SEM)
Catalyst loading
Detailed Morphology of GDL
Atomic Force Microscopy (AFM)
Topography of Membranes
19. Optical Microscopy
Capability to magnification up to 400 and 1000 times the objects original size
Alkaline Membrane
Catalyst Layer
20. Scanning Electron Microscopy
In SEM electrons are used to capture an image instead of light
SEM scans the sample with a high energy beam of electrons
As electrons hit a sample, other electrons are ejected and converted into other forms
typical resolution of SEM is around 5 nm
21. Scanning Electron Microscope
Gas Diffusion Layer 150X
Gas Diffusion Layer 1510X
22. Atomic Force Microscopy
AFM consists of a cantilever with a probe mounted at the end
The probe is brought near the surface of the specimen and the deflection of the cantilever is measured
AFM has a resolution of 0.1 nanometers and can be used to view atoms
23. Performance Evaluation
Polarization Curve
Plot of the voltage vs current density
Shows polarization losses
Activation losses
Ohmic Losses
Concentration Losses
Power Curve
Plot of power on a voltage vs current graph
24. Results: Polarization and Power
25. Results: Temperature
26. Results: Oxygen Concentration
27. Results: Experimental Membranes
C-40
Generate voltage of .856 V with no measurable current
Ionic conductivity of 4.1(10-3) S/cm at 15C
229 (Alkaline)
Generated voltage of .153 V with no measurable current
Ionic conductivity of .0112 S/cm when hydrated at 60-80C
Nafion 117
Generated of .95 V
Ionic conductivity of .083 S/cm
28. Experimental Membranes
Voltage of experimental membranes show promising results
Still in the initial testing stages
Experimental membranes are designed to operate at higher temperatures than Nafion which is limited to below 100C
The experimental membranes are thicker than Nafion increasing their resistance
Recommend that membranes be made thinner
29. Challenges and Solutions
Electronic Fuel Cell Load
Little knowledge of how to use machine
Spent hours on phone with manufacturer for weeks
Leakage
Different gasket shapes
Did many leak tests to find out where the fuel cell was leaking
Applied vacuum grease to the O-rings
30. Challenges and Solutions
Humidity Sensor
GDLs were not as flexible as originally thought and caused humidity sensor to not fit into its designated space
Humidity Sensor kept shorting out
Added varnish to the flow plate and leads of humidity sensor
Added silicone to flow plate and the leads
Insulated the leads with jackets
Used a Dremmel to shave off any unnecessary plastic from the humidity sensor.
Pressure that was safe for the fuel cell stack was much lower than the pressure that the experiments were supposed to take place at
31. Challenges and Solutions
Bolts
If the bolts are tightened too much, the gaskets block the channel
If the bolts are too loose, then the GDL and membrane dont have enough contact and there is no current
Found optimal torque to be 6 lb-in
After one use, Nafion becomes deformed and is pushed into the flow channels by the gaskets and blocks the channel.
Thermocouple picking up signals from the EFCL
32. Design Recommendations
Deeper channels
Allow for gasket to deform into channel without restricting flow
Change flow channel design
Eliminate the need for holes in the membranes and gaskets to prevent leakage and cross over of gases
Use sensors specifically made to be in a conductive environment
Prevent sensors from short circuiting between flow plates or Gas Diffusion Electrodes
33. Design Recommendations
Use a larger fuel cell
Add polyurethane coating to thermocouple for insulation
Know the mechanical properties of the GDL is before designing a modified flow plate
34. Conclusions
A Fuel Cell Test Stand was successfully designed, fabricated, and tested.
A data acquisition system was designed and implemented to measure Pressure, Temperature, Oxygen Concentration, and Relative Humidity.
Characterizations of Gas Diffusion Electrode and Membrane materials were made.
Advanced Laboratory Techniques were learned including Optical Microscopy, Scanning Electron Microscopy, and Atomic Force Microscopy.
35. Acknowledgements
Our Advisors Dr. Shrestha, Dr. Ghantasala, and Dr. Bliznyuk
Dr. V. Schevchenko Institute of Macromolecular Chemistry
Dr. Hathaway
Pete Thannhauser
Abraham Poot
Glenn Hall
Rex Harding
Melissa Wagner
36. Any Questions?Thank You