Fuel Cells and Hydrogen Storage Brian Ninneman 2/7/2005

Overview Introduction to Fuel Cells Introduction to Fuel Cells Fuel Cells in the Automotive Industry Fuel Cells in the Automotive Industry Types of Fuels and Hydrogen Storage Types of Fuels and Hydrogen Storage In the News… In the News…

History Invented in the early 1840’s by Sir William Robert Grove [1] Invented in the early 1840’s by Sir William Robert Grove [1] In 1890’s Nernst develops the first solid oxide fuel cell In 1890’s Nernst develops the first solid oxide fuel cell Relatively few documented cases of fuel cell breakthroughs between mid-1800’s and 1950’s Relatively few documented cases of fuel cell breakthroughs between mid-1800’s and 1950’s Resurgence of alkaline fuel cells created by General Electric for Gemini and Orbiter space programs [2] Resurgence of alkaline fuel cells created by General Electric for Gemini and Orbiter space programs [2] In the 60’s DuPont designed the membrane still used in most PEM fuel cells today, Nafion ® In the 60’s DuPont designed the membrane still used in most PEM fuel cells today, Nafion ® In the 80’s there was a breakthrough in the reduction of catalyst amount needed In the 80’s there was a breakthrough in the reduction of catalyst amount needed

5 Types of Fuel Cells Phosphoric Acid Phosphoric Acid Alkaline Alkaline Solid Oxide Solid Oxide Molten Carbonate Molten Carbonate Proton Exchange Membrane Proton Exchange Membrane

Solid Oxide FC [1] Uses a hard ceramic material of zirconium oxide combined with ytrria as electrolyte Uses a hard ceramic material of zirconium oxide combined with ytrria as electrolyte Operating temperature of 1,000 o C Operating temperature of 1,000 o C Operates at 45-60% efficiency, 85% with cogeneration Operates at 45-60% efficiency, 85% with cogeneration Mainly used for industrial applications, may be used in automobiles as an auxiliary power unit Mainly used for industrial applications, may be used in automobiles as an auxiliary power unit Power output of 100 kW Power output of 100 kW

Molten Carbonate FC [1] Uses liquid solution as electrolyte, usually Li +, Na +, and/or K + carbonates Uses liquid solution as electrolyte, usually Li +, Na +, and/or K + carbonates Operating temperature of 650 o C Operating temperature of 650 o C Operates at 40-60%, 85% with cogeneration Operates at 40-60%, 85% with cogeneration Produces water and carbon dioxide Produces water and carbon dioxide Mainly used for stationary power generation Mainly used for stationary power generation Power output of 10 kW to 2 MW Power output of 10 kW to 2 MW

Proton Exchange Membrane FC [1] Utilizes a polymer membrane as the electrolyte (poly-perflourosulfonic acid, Nafion ® [3] ) Utilizes a polymer membrane as the electrolyte (poly-perflourosulfonic acid, Nafion ® [3] ) Operate at much lower temperatures, ~80 o C Operate at much lower temperatures, ~80 o C Operates a 35-60%, 85% cogeneration Operates a 35-60%, 85% cogeneration Produces water Produces water Mainly used in mobile applications Mainly used in mobile applications Power output of kW Power output of kW

PEM FC Design Components Membrane/Electrode Assembly Membrane/Electrode Assembly Gas Diffusion Layer Gas Diffusion Layer Bipolar plates Bipolar plates DuPont Conductive Plates,

Operation of PEM FC

PEM FC Design [4] Membrane should have high proton conductivity and low water permeability Membrane should have high proton conductivity and low water permeability Electrodes function best when made of noble metal catalysts Electrodes function best when made of noble metal catalysts Optimal channel geometry for cathode side of bipolar plating Optimal channel geometry for cathode side of bipolar plating Minimizing width between channels Minimizing width between channels Decreasing channel cross-section Decreasing channel cross-section Increasing channel depth Increasing channel depth

PEM FC Design (Cont.) [4] Water Management Water Management Drying leads to decreased performance of the cell from decreased conductance Drying leads to decreased performance of the cell from decreased conductance Saturation with water causes degradation of fuel cell materials, decreases mass transfer Saturation with water causes degradation of fuel cell materials, decreases mass transfer Heat Management Heat Management Increasing the temperature is often used to vaporize water and increase mass transport Increasing the temperature is often used to vaporize water and increase mass transport The waste heat from PEM’s is of limited usage because of little temperature difference The waste heat from PEM’s is of limited usage because of little temperature difference

Energy Efficiency [1,2]

Efficiency cont. Produce energy through electrochemistry rather than chemical combustion Produce energy through electrochemistry rather than chemical combustion Fuel cells do not obey the efficiency limitations of the Carnot Cycle Fuel cells do not obey the efficiency limitations of the Carnot Cycle Increase efficiency by: Increase efficiency by: Increasing temperature Increasing temperature Tradeoff between efficiency and power density Tradeoff between efficiency and power density Described through the polarization curve Described through the polarization curve

Polarization Curve [4]

Fuel Cells in the Automotive Industry Comparing: Comparing: Availability/Cost Availability/Cost Power density Power density Lifetime Lifetime Fuel sources Fuel sources Hydrogen storage Hydrogen storage pem_fuelcell/index.shtml

Availability and Cost Until the 1980’s only high cost fuel cells existed because of large amounts of noble metals in catalyst Until the 1980’s only high cost fuel cells existed because of large amounts of noble metals in catalyst Begin to see emergence of research in late 80’s for use in automobiles Begin to see emergence of research in late 80’s for use in automobiles PEM’s seen a main viable fuel cell for use in automobiles PEM’s seen a main viable fuel cell for use in automobiles Internal combustion engines cost ~$20/kW [5] Internal combustion engines cost ~$20/kW [5] Prototype fuel cells cost $3,000/kW [1] Prototype fuel cells cost $3,000/kW [1]

Power Density and Energy Utilization Far greater power density for internal combustion engines than fuel cells [6] Far greater power density for internal combustion engines than fuel cells [6] ~600 hp for 4-door sedan ~600 hp for 4-door sedan ~100 hp for electric vehicle ~100 hp for electric vehicle Better energy utilization for fuel cells [4] Better energy utilization for fuel cells [4] 1:1 electricity-to-heat for fuel cells 1:1 electricity-to-heat for fuel cells 1:3 electricity-to-heat for internal combustion engines 1:3 electricity-to-heat for internal combustion engines

Power Density [2,6]

Lifetime of Fuel Cell [1] Fuel cells last much longer than internal combustion engines because of lack of moving parts Fuel cells last much longer than internal combustion engines because of lack of moving parts Combustion engines last ~5,000 hours of usage Combustion engines last ~5,000 hours of usage Fuel cells last >40,000 hours of usage Fuel cells last >40,000 hours of usage Fuel cells used in the space programs in the 60’s have been used for 100,000 hours without faulty operation and minimal maintenance Fuel cells used in the space programs in the 60’s have been used for 100,000 hours without faulty operation and minimal maintenance

Infrastructure [1] Oil industry currently spends $11 billion/year to maintain service station fleet Oil industry currently spends $11 billion/year to maintain service station fleet Natural gas pipeline extension costs $5 billion/year Natural gas pipeline extension costs $5 billion/year Independent studies have developed nationwide models costing $15 billion to install infrastructure based on 1 million FC vehicles and fueling stations within 2 miles of homes for 70% of the population Independent studies have developed nationwide models costing $15 billion to install infrastructure based on 1 million FC vehicles and fueling stations within 2 miles of homes for 70% of the population

Fuels for Fuel Cells [1,2,4] Hydrogen derived from: Hydrogen derived from: Water Water Methanol Methanol Ethanol Ethanol Natural gas Natural gas Renewable resources (wind, solar, biomass, etc.) Renewable resources (wind, solar, biomass, etc.) Hydrocarbons Hydrocarbons

Hydrogen Production [7]

Hydrogen Storage Metal hydrides Metal hydrides Pressurized hydrogen gas Pressurized hydrogen gas Liquefied hydrogen Liquefied hydrogen

Metal Hydrides [2,8] Will theoretically store 5.6 wt.% of hydrogen using a NaAlH 4, presently store ~3% Will theoretically store 5.6 wt.% of hydrogen using a NaAlH 4, presently store ~3% Comparing the weight of the metal hydride to gasoline, 5 times of the hydride alone will be needed to travel similar distances Comparing the weight of the metal hydride to gasoline, 5 times of the hydride alone will be needed to travel similar distances ~ ½ an hour to charge the metal hydride with hydrogen ~ ½ an hour to charge the metal hydride with hydrogen

[8] Hydrogen Capacity for Consecutive Charges

Pressurized Gas Will store 10 wt.% hydrogen in light weight tanks [9] Will store 10 wt.% hydrogen in light weight tanks [9] Tanks utilize a carbon fiber wrap and polymer liner Tanks utilize a carbon fiber wrap and polymer liner Currently, not able to store at >10,000 psi Currently, not able to store at >10,000 psi [9]

Liquefied Hydrogen [10] Widely used in prototype vehicles Widely used in prototype vehicles Storage conditions of 20 K and 1 bar Storage conditions of 20 K and 1 bar Issues: Issues: Need of robotic fueling stations Need of robotic fueling stations Amount of energy needed to liquefy the hydrogen Amount of energy needed to liquefy the hydrogen Current research efforts involve designing use of cryogenic tanks for both gas and liquid along with better insulating materials Current research efforts involve designing use of cryogenic tanks for both gas and liquid along with better insulating materials

Hydrogen Safety [9,11] Hydrogen has been produced and transported in the U.S. >50 years Hydrogen has been produced and transported in the U.S. >50 years Hydrogen gas diffuses rapidly Hydrogen gas diffuses rapidly Ford Motor Co. released a report in 1997 examining safety of hydrogen use in vehicles Ford Motor Co. released a report in 1997 examining safety of hydrogen use in vehicles

In the news… Aug. 10, 2004 – Ford produces 30 Ford Focus Fuel Cell Vehicles to be tested in real world Aug. 10, 2004 – Ford produces 30 Ford Focus Fuel Cell Vehicles to be tested in real world Oct. 25, GM designing hydrogen powered HUMMER H2 Oct. 25, GM designing hydrogen powered HUMMER H2 Jan 25, 2005 – GM and Shell team up to begin production of fuel cell feel for New York Jan 25, 2005 – GM and Shell team up to begin production of fuel cell feel for New York

Questions?

References 1 – Breakthrough Technologies Institute, 1 – Breakthrough Technologies Institute, 2 – Appleby A.J., “Fuel Cell Technology and Innovation,” Journal of Power Sources, v. 37, pp , – Appleby A.J., “Fuel Cell Technology and Innovation,” Journal of Power Sources, v. 37, pp , – DuPont Nafion ® Membranes, 3 – DuPont Nafion ® Membranes, – Mennola T., “Mass Transport in Polymer Electrolyte Membrane Fuel Cells Using Natural Convection for Air Supply,” 4 – Mennola T., “Mass Transport in Polymer Electrolyte Membrane Fuel Cells Using Natural Convection for Air Supply,” Helsinki University of Technology Publications in Engineering Physics, – Mench M.M., et al., “An Introduction to Fuel Cells and Related Transport Phenomena,” The Penssylvannia State University 6 – GM Fuel Cell Program Website, +cell +cell

References 7 – Conte M., et al., “ 7 – Conte M., et al., “Hydrogen Economy for a Sustainable Development: State-of-the- Art and Technological Perspectives,” Journal of Power Sources v. 100, pp , – Gross K.J., et al., “Hydride Development for Hydrogen Storage,” Proceedings of the 2000 Hydrogen Program Review 8 – Gross K.J., et al., “Hydride Development for Hydrogen Storage,” Proceedings of the 2000 Hydrogen Program Review 9 – Mitlitsky F, et al., “Vehicular Hydrogen Storage using Lightweight Tanks,” Proceedings of the 2000 U.S. DOE Hydrogen Program Review 9 – Mitlitsky F, et al., “Vehicular Hydrogen Storage using Lightweight Tanks,” Proceedings of the 2000 U.S. DOE Hydrogen Program Review 10 – Armstrong T.R., et al., “Hydrogen Storage Research Activities at Oak Ridge National Laboratory,” 10 – Armstrong T.R., et al., “Hydrogen Storage Research Activities at Oak Ridge National Laboratory,” Safety and Economy of Hydrogen Transport Symposium. Sarov, Nizhny Novgorod Region, Russia. Aug 18-23, 2003 ” Ford Motor Co., May – Bain A., et al., “Direct-Hydrogen-Fueled Proton-Exchange-Membrane Fuel Cell System for Transportation Applications: Hydrogen Vehicle Safety Report,” Ford Motor Co., May 1997