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Lunch Vietnam seminar-University of Michigan August 14, 2008

Lunch Vietnam seminar-University of Michigan August 14, 2008. Fundamentals of Fuel Cells. Presenters Do Ba Thanh & Nguyen Huu Phuoc Nguyen. Outline. Introduction: + Energy and Environmental aspects: N + Why we need fuel cell? N + Hydrogen economy N + Fuel cells categories

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Lunch Vietnam seminar-University of Michigan August 14, 2008

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  1. Lunch Vietnam seminar-University of MichiganAugust 14, 2008 Fundamentals of Fuel Cells Presenters Do Ba Thanh & Nguyen Huu Phuoc Nguyen

  2. Outline Introduction: + Energy and Environmental aspects: N + Why we need fuel cell? N + Hydrogen economy N + Fuel cells categories Operation of fuel cell N- a T Fuel cell applications a T Fuel cell problems N-a T Research direction N- a T FC in VN- a T Conclusion

  3. Energy, now and in future • We are relying on fossil fuel [1] Fig: World energy demand development Fig: World energy sources - Percentage *http://en.wikipedia.org/wiki/World_energy_resources_and_consumption

  4. Energy, now and in future How long can fossil fuel reserve last? [2] • Oil: 1,050 to 1,277 billion barrels (167 to 203 km³) • Gas: 6,040 - 6,806 trillion cubic feet (171,000 to 192,700 km³) • Coal: 1,081,000 million tons By the current consumption rate: • Oil: 45 years • Gas: 72 years • Coal: 252 years * http://en.wikipedia.org/wiki/Fossil_fuel

  5. Energy, now and in future • The actual oil peak curves [3] Fig: World oil production vs time Fig: Oil production vs time curves for countries, except Middle East and former Soviet Union

  6. Energy, now and in future • Fossil fuel also create other serious problems Environmental pollution: one gallon of gas burned releases 2.3 kg of carbon in form of gases! Global warming Dependence on oil-rich countries Therefore, fossil fuel is NOT our future! http://staffwww.fullcoll.edu/tmorris/elements_of_ecology/images/greenland_icemelt_2002.jpg

  7. Why we need fuel cell? • There for the situation poses two major challenges: - Find a new source of energy • Make the new source economically and environmentally viable • To solve overcome these challenges, we are, being predicted that, heading toward the Hydrogen Economy, where fuel cell play a major role.

  8. Hydrogen Economy Renewable energy sources: • Solar, wind, hydropower, biofuel, geothermal • Energy carrier: Hydrogen • “Green Engine”: Fuel Cell *http://en.wikipedia.org/wiki/Renewable_energy

  9. Energy Diversity Type and percentage of renewable energy sources ** F. Barbir, PEM Fuel Cells, theory and practice, Elsevier Academic Press,2005

  10. What is a fuel cell A brief overview * * PEM Fuel Cells, theory and practice, F. Barbir, Elsevier Academic Press,2005

  11. What is a fuel cell

  12. Fuel cell classification* • More than 20 types of FC classified according to their electrolyte, fuel, and operating temperature** • Proton Exchange Membrane FC (PEMFC) is the most promising one from its high power density and low operating temperature (60-80oC) [*] http://en.wikipedia.org/wiki/Fuel-cell [**] Larminie L., Dicks A., Fuel cell systems explained,Wiley, 2004, 2nd Edition

  13. Fuel Cell Efficiency • Tank-to-wheel efficiency: With pure H2, FC is up to 90% Electrical-mechanical conversion: 80% Overall: 72% Ex: Honda’s FCX concept vehicle 60% • Power-plant-to-wheel efficiency: Energy is needed to produce, store, transport H2. The overall efficiency is around 22% [6] Theoretical : 33% Practical max: 26% [5] [6] http://www.efcf.com/reports/E04.pdf

  14. Similarities: No moving parts during operations, so they work quietly and requires minimum maintenance Flexible in design (scale, shape and capacity) High efficiency (H% is about 90%>> internal combustion engine with H% ~33%) Differences Fuel Cells Various fuel sources In-situ energy generation Operations of Fuel Cells and Battery • Battery: • Reactants can be regenerated • Built-in energy storage

  15. Operation of Fuel Cells • Similar to that of battery: direct conversion of chemical energy into electrical energy • The electrons produced at anode move to cathode to produce electricity. Anode: 2H2-4x1e = 4H+ Cathode: O2 + 2x2e+4H+ = 2H2O Overall: 2 H2 + O2 = H2O http://www.esru.strath.ac.uk/EandE/Web_sites/00-01/fuel_cells/fuel%20cell%20operation.html

  16. Reactions inside Fuel Cells The reaction of H2 to O2 is very difficult at normal condition (10-4% after 2000 yrs) What does it make reactions inside FCs occurred? There are various types of Fuel Cells Is there any difference in operation between different fuel cell’s types?

  17. Electrode and reactions on its surface • Electrodes consist of two conductive and porous layers • Supportive layer is covered by catalyst for the redox reactions • Catalyst predominantly is Pt nano particles distributed on support’s suface • Pt catalyzes the redox reactions at normal conditions Schematic of electrode structure for fuel cells * * Spiegel C. S.-Designing & Building Fuel Cells, McGraw-Hill Co., 2007

  18. Reactions on PEM fuel cells Schematic of PEM fuel cells* Electrolyte is a membrane which is porous and able to exchange proton Anode: 2H2 -4x1e = 4H+ Cathode: O2 +2x2e + 4H+ = 2H2O Reaction in total: 2H2 + O2 = 2H2O * Barbir-PEM Fuel Cells: Theory and Practice, Elsevier, 2005

  19. Reactions on PA fuel cells Schematic of PA fuel cells* Electrolyte is the solution of phosphoric acid Anode: 2H2(g) -4x1e = 4H+(aq) Cathode: O2(g) + 4H+(aq)+2x2e = 2 H2O(l) Overall: H2(g) + ½ O2(g) + CO2(g) = H2O(l) + CO2(g) * Barbir-PEM Fuel Cells: Theory and Practice, Elsevier, 2005

  20. Reactions on Alkali fuel cells Electrolyte is the solution of KOH (Potasium hydroxide) Anode: 2H2(g) + 2OH-(aq) – 2x1e = 4H2O(l) Cathode: O2(g) + 2H2O(l) + 2x2e = 4OH-(aq) Overall: 2H2(g) + O2(g) = 2H2O(l) Barbir-PEM Fuel Cells: Theory and Practice, Elsevier, 2005

  21. Reactions on Solide Oxide fuel cells Schematics of SOFCs (b) Schematic of Solid Oxide electrode (a) Electrolyte is a non porous solid Y2O3-stabilized ZrO2, melt at 1000oC Anode: H2(g) + O2-(melt) – 2x1e = H2O (g) Cathode: ½ O2(g) + 2e = O2- (oxide) Overall: H2(g) + ½ O2(g) = H2O(g) • http://www.sciencemag.org/cgi/content/full/288/5473/2031/F1 • Barbir-PEM Fuel Cells: Theory and Practice, Elsevier, 2005

  22. Reactions on Direct Methanol fuel cells Schematic of DMFCs * Similar structure to PEMFCs, but using methanol/ethanol as fuel to generate H+ Anode: CH3OH(l) + H2O(l) = CO2(g) + H+(aq) + 6e Cathode: 6H+ + 3/2O2(g) + 6e = 3H2O(l) Overall: CH3OH(l) + 3/2O2(g) = CO2(g) + 2H2O(l) * Barbir-PEM Fuel Cells: Theory and Practice, Elsevier, 2005

  23. Applications of Fuel Cells Transportation Vehicles Aerospace Exploration Power generation stations Handheld Devices

  24. Fuel Cells for automotives Toyota FCHVPEM FC fuel cell vehicle A hydrogen fuel cell public bus accelerating at traffic lights in Perth, Western Australia http://en.wikipedia.org/wiki/Fuel_cell

  25. Some pictures of fuel cells used in bus H2 cylinders Fuel cells location

  26. Fuel Cells for automotives • Requirements: • Size • Power density: Higher Energy in a volume unit of cell • PEMFCs has been mostly used for this purpose: • Does not require initial energy supply to initiate the operation of FCs • Higher power density than other FCs types • Dry electrolyte

  27. Fuel Cell Problems • Cost: from infrastructure construction and materials.Currently: $110/ kW. To be competitive: $35/kW • Durability of materials, especially at high temperature and severe working conditions of fuel cells • Design and modeling of fuel cells to acquire the humidity, air and hydrogen flow rates, thermal and mass transportation in and out from FCs • The availability of infrastructure and production of hydrogen

  28. FC research areas * • Heat transfer • Mass Transfer • Water management • Membrane material • Catalyst • Control system *http://www.fuelcellsworks.com/Supppage8788.html

  29. Futures of FCs • Being considered as a promising and predominant energy source for the future • Research on FCs has been dramatically increased • There are still many obstacles for the wide application of FCs

  30. Challenges for FCs-Hydro infrastructure • Mass production of H2: - Steaming reforming: C, CH4 + H2O(g) H2 + CO2 (green gas pollution) - Water electrolysis: H2O --- H2 + ½ O2 (costly) - Bacteria/algae decomposition of water: very slowly • H2 Storage - Physically: Compressed or liquidified: dangerous - Chemically: metal hydride (LiH, LiAlH4) or easy decomposable compounds of H2 (NH3, H2O2): low volume capacity, costly • H2 refill station and safety issues: safety and cost issues

  31. Cathode Membrane Anode Fresh After 80 cycles J. Power Sources, 158, 1306 (2006) Challenges for FCs-Materials • Materials to make anode and cathode are not durable enough for long life use purpose • Research on new material generations just started and requires a lot of efforts • Catalyst Pt is so expensive and its capacity is limited for mass use • Catalyst Pt is easily poisoned by CO gas or chemicals (*) (*) http://www.nature.com/nmat/journal/v1/n4/pdf/nmat782.pdf

  32. Research and development of FCs in VN • Not any strategic research on FCs is available in VN • VN wants to work on nuclear E-resource than renewable energy resources • Joint-ventured production of C2H5OH is asking for the investment

  33. The opportunity for VEF fellows of UMich unit We have expertise working on: • Materials synthesis and characterization for the research on materials • Chemistry and chemistry engineering for the modeling • Mechanical engineering for designing and testing Can UMich VEF fellows do something for the development of this research field in VN?

  34. Conclusions • We reviewed some fundamentals of fuel cells in the relevance, operations and current research interests of fuel cells • The basics of FCs are simple, but its research and application requires a lot of knowledge on various disciplines • There are still many challenges in infrastructure for the wide application of FCs • VEF fellows in the University of Michigan unit has an opportunity to work together for the initiation and development of this research field in Viet Nam

  35. Thank you

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