Fuel Cells and the Hydrogen Economy July 2012 Sustainable Energy Workshop for Science and Technology Teachers (SEWFSTT) Module 2 Fuel Cells and the Hydrogen Economy “This product was funded by a grant awarded under te Workforce Innovation In Regional Economic Development Initiative as implemented by the U.S. Department of Labor’s Employment and Training Administration. The information contained in this product was created by a grantee and does not necessarily reflect the official position of the U.S. Department of Labor. All references to non-governmental companies or organizations, their services, products, or resources are offered for information purposes and should not be construed as a endorsement by the Department of Labor. This product is copyrighted by the institution that created it and is intended for individual organization, non-commercial use only.” Sustainable Energy Workshop 1

Module 02: Fuel Cells - Outline Definition and Overview PEM Fuel Cells Teaching about Fuel Cells Cellular Structure – Batteries Relationship The Hydrogen Economy Challenges and Advantages

Fuel Cells July 2012 Section 01: Definition and Overview Goal: Understand basic structure of a fuel cell Basic definition of a fuel cell Central chemistry of fuel cells Overview of types of fuel cells Sustainable Energy Workshop

Fuel Cells Fuel Cells July 2012 Top: http://physics.nist.gov/MajResFac/NIF/Images/FuelCellBasic.gif Lower Left: http://www.easternct.edu/depts/sustainenergy/energy/fuel%20cells.htm Middle Top: http://fuelcellstore.com/en/pc/catalog/2090FuelCellStack3.jpg Middle Bottom: http://www.nytimes.com/2007/12/09/automobiles/09equinox.html Upper Right: http://www.evworld.com/images/gm_volt_fuelcell_diagram.jpg Lower Right: Pictures from Kettering Sustainable Energy Event, Sept. 2006: http://www.kettering.edu/visitors/storydetail.jsp?storynum=485 Sustainable Energy Workshop

Discussion: Prior Exposure with Fuel Cells July 2012 Discussion: Prior Exposure with Fuel Cells (outside of the automotive industry) Sustainable Energy Workshop

Fuel Cells come in all shapes and sizes July 2012 Fuel Cells come in all shapes and sizes 2 6 8 7 4 7 1) Pictures from Kettering Sustainable Energy Event, Sept. 2006: http://www.kettering.edu/visitors/storydetail.jsp?storynum=485 2) http://www.fuelcelledu.com/images/products/htec/2112_FuelCellJuniorH2Air.jpg 3) Toshiba MP3 http://img.engadget.com/common/images/0546533664464177.JPG?0.12789605864708142 4) http://www.gastechnology.org/webroot/app/xn/xd.aspx?it=enweb&xd=4reportspubs\4_8focus\directmethanolfuelcellfocus.xml 5) http://www.easternct.edu/depts/sustainenergy/energy/fuel%20cells.htm 6) KeelyNet http://www.keelynet.com/fcrobotic.jpg 7) Pictures from Kettering Sustainable Energy Event, Sept. 2006: http://www.kettering.edu/visitors/storydetail.jsp?storynum=485 8) http://www.maxmoto.co.uk/images/aprilia_fuel_cell_2l.jpg 9) Pictures from Kettering Sustainable Energy Event, Sept. 2006: http://www.kettering.edu/visitors/storydetail.jsp?storynum=485 3 5 Sustainable Energy Workshop

Basic Definition of a Fuel Cell Fuel Cells Basic Definition of a Fuel Cell July 2012 Electrochemical Energy Conversion Device http://www.diymobileaudio.com/forum/off-topic/48060-battery.html Key difference – fuel cells will have ‘flow through’ properties Sustainable Energy Workshop

Different Kinds of Fuel Cells July 2012 What makes them different? Electrolyte, Operating Temperature … (Application) Sustainable Energy Workshop

Section 02: PEM Fuel Cells Goal: Detailed understanding of operation of PEM fuel cells Central Chemistry - Redox General Process in Fuel Cell Structure/Parts of a Fuel Cell Step-by-Step Operations

Energy Conversion: PEM Fuel Cell Fuel Cells Energy Conversion: PEM Fuel Cell July 2012 Hydrogen and oxygen are combined in a non-combustion process Electricity, heat and water are produced Reduction-Oxidation Rxn (redox) Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons. The anode is the electrode where oxidation occurs and mass is lost where as the cathode is the electrode where reduction occurs and mass is gained. Anode Half-Reaction Cathode Half-Reaction Sustainable Energy Workshop

Electric Potential Developed Fuel Cells July 2012 Electric Potential Developed Redox potential is a measure of a substance’s electronegativity (affinity for electrons) “Downhill” in Energy Diagram -- Free energy Don’t have oxidation reaction without reduction reaction present at same time (matched set) Nernst Equation Calculation of electric potential in “non-ideal” circumstances Oxidation Half-Reaction V(SHE) = Standard Hydrogen Electrode  defined as zero for Hydrogen (uses Hydrogen as reference point)  4.4V 1.23 V is open-circuit potential Reduction Half-Reaction Sustainable Energy Workshop

Proton Exchange Membrane Fuel Cell Fuel Cells July 2012 Proton Exchange Membrane Fuel Cell (Polymer Electrolyte Membrane) Oxidation reaction facilitated by a catalyst - typically Pt ($$$) Between the reduction and oxidation stages, the electrons are routed through a circuit Hydrogen ions (protons) permeate through the electrolyte membrane Reduction reaction http://alternativefuels.about.com/od/researchdevelopment/ig/Fuel-Cell-Diagrams/PEM-Fuel-Cell.htm 1.23 V Sustainable Energy Workshop

Power Produced – Watts/m2 Activation Loss potential difference above the equilibrium value required to produce a current (depends on activation energy of the reaction) energy is lost as heat Ohmic Loss voltage drop due to resistance of the cell components and interconnects Mass Transport Loss depletion of reactants at catalyst sites under high loads

PEM (Polymer Electrolyte Membrane) Polymers such as polyphenylenes, Nafion are used Water is a crucial participant in the process absorption of water increases the proton conductivity membrane is confined – not free to swell – pushes electrodes

PEM (Polymer Electrolyte Membrane) Fuel Cells July 2012 PEM (Polymer Electrolyte Membrane) Thickness of the membrane and catalyst in the PEM can vary … Example: catalyst layers containing about 0.15 milligrams (mg) Pt/cm2 thickness of the catalyst layer is close to 10 micrometers yields a MEA with a total thickness of about 200μm (or 0.2 mm or 20 sheets of paper) generates more than half an ampere of current per cm2 at a voltage of 0.7 volts http://www1.eere.energy.gov/hydrogenandfuelcells/animation/images/fmodsingle2.gif Platinum needs to be placed to maximize surface area Needs to be encased in engineered components Sustainable Energy Workshop

Design Goals: Limited Overview Deliver Hydrogen Deliver Oxygen Chemical reaction – what can influence rate of reaction Water Management Maintain hydration levels Remove water by-product Efficient path for electrons to ‘migrate’ to electrodes Thermal management

Parts of a Fuel Cell Bipolar Plates Anode Cathode Fuel Cells July 2012 Bipolar Plates Serpentine channels for hydrogen and oxygen to flow through device Acts as a current collector – electrons enter and exit cell through the plate Anode Conducts electrons away from catalyst to external circuit Channels to supply H2 evenly to the surface of the catalyst Cathode Channels to supply O2 evenly to the surface of the catalyst Conducts electrons back to catalyst for recombining http://www.britannica.com/EBchecked/topic-art/221374/100899/Proton-exchange-membrane-fuel-cell-The-proton-exchange-membrane-is Sustainable Energy Workshop

Parts of a PEM Fuel Cell Membrane Electrode Assembly Anode Cathode Fuel Cells Parts of a PEM Fuel Cell July 2012 Membrane Electrode Assembly Anode Cathode PEM (Polymer Electrolyte Membrane) conducts only positively charged ions blocks electrons and other substances Catalyst thin coat of platinum powder applied to carbon paper or cloth maximizes surface area Backing Layers porous carbon cloth conducts electrons away from catalyst to external circuit allows right amount of water vapor to enter/exit too much blocks the pores membrane needs to be humidified Bottom: http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_parts.html Sustainable Energy Workshop

Schematic of Fuel Cell Operation Fuel Cells July 2012 Schematic of Fuel Cell Operation 1.2 V = theoretical maximum voltage generated by this reaction http://physics.nist.gov/MajResFac/NIF/Images/FuelCellBasic.gif Typical output = 0.7V – 0.9V ….. (1 W per cm2) Sustainable Energy Workshop

Schematic of Fuel Cell Operation Fuel Cells July 2012 Schematic of Fuel Cell Operation Anode Hydrogen gas is circulated through ‘serpentine’ channels Hydrogen from channels passes through porous medium (gas diffusion backing) Electron is stripped from Hydrogen as it makes contact with Pt catalyst which is embedded in a carbon nanoparticle http://physics.nist.gov/MajResFac/NIF/Images/FuelCellBasic.gif Hydrogen nucleus (proton) passes through PEM membrane to cathode Electron conducted away through circuit Sustainable Energy Workshop

Schematic of Fuel Cell Operation Fuel Cells July 2012 Schematic of Fuel Cell Operation Cathode Oxygen gas is circulated through ‘serpentine’ channels Oxygen from channels passes through porous medium (gas diffusion backing) Electrons from circuit come in to contact with Oxygen atom and Protons (Hydrogen nuclei) passing through the PEM membrane http://physics.nist.gov/MajResFac/NIF/Images/FuelCellBasic.gif Hydrogen and Oxygen recombine to form water & exit Excess Oxygen exits the fuel cell Sustainable Energy Workshop

Activity: PEM Fuel Cell Car (Pairs) Fuel Cells July 2012 Activity: PEM Fuel Cell Car (Pairs) Outline: Produce hydrogen and oxygen via electrolysis Use stored H2 and O2 to generate electricity and drive motor Educational Objectives for this Activity: Recognize H2 and O2 as portable fuels: same role as gasoline in an IC engine Recognize that a separate process is required to produce hydrogen Observation of the relationship between the volumes of displaced water in the hydrogen and oxygen tanks (and relationship to redox equations) Recognize that the hydrogen and oxygen produced came from initial injection of water Discussion of extension activities http://www.fuelcellstore.com/en/pc/catalog/fcs_intcar2_large_general.jpg Sustainable Energy Workshop

Parts Identification Battery components Chassis Fuel Cell Battery pack 2 AA Batteries Connection Cable Add batteries to battery pack Chassis Fuel Cell Identify Hydrogen and Oxygen side Incredibly important! H2 and O2 Storage Tanks Two cylinders + 2 cup-like caps w/ long hoses attached … but wait … there’s more …

Parts Identification Hydration Components Syringe Two short, narrow tubes with black and red caps Short length of wide tubing 90mL of distilled water + cup Very important - needs to be distilled water (NOT Purified water) ------ Why? If you do not ALSO have a short length of wide tubing, you’re OK – just remove the black plug and use the narrow tube

Hydrate Fuel Cell Fill the syringe with distilled water and (gently) inject a small amount in to the LOWER nozzle on the HYDROGEN side You will see the water fill in the fuel cell – you can go all the way until the water pours out the top nozzle. GENTLY Remove the syringe and insert the tube with the black cap in the LOWER nozzle

Hydrate Fuel Cell Fill the syringe with distilled water and (gently) inject a small amount in to the LOWER nozzle on the OXYGEN side You will see the water fill in the fuel cell – you can go all the way until the water pours out the top nozzle. Remove the syringe and insert the tube (red cap) in the LOWER nozzle GENTLY O2

Prepare to Generate Hydrogen and Oxygen Insert the cup-like caps in to the Hydrogen and Oxygen tanks 0 mL Align the notch in the cap with the gap in the tank we want to allow trapped air to escape when we fill the tanks with water Fill the tanks to the zero (0) mL mark with distilled water Suggestion: Use the syringe (each will take about 30mL)

Prepare to Generate Hydrogen and Oxygen Connect the tank hoses to the upper nozzles on their respective sides (i.e. Hydrogen tank to Hydrogen nozzle) Don’t forget to connect the Oxygen side too!

Prepare to Generate Hydrogen and Oxygen Make sure battery pack is turned off Connect battery pack to connector Connect banana plugs to fuel cell (black to black, red to red) Don’t turn it on yet …..

(Black-to-Black, Red-to-Red) Double -Check Double check connections (Black-to-Black, Red-to-Red) Turn on the battery pack and observe the production of H2 and O2

Disconnect Battery Pack You now have a full ‘gas tank’ and a flow-through battery Need a DC motor and wheels to drive a car

Transfer Assembly to Car and Connect Motor As a unit, transfer the gas tanks and the fuel cell to the car chassis Connect the banana plugs from the motor to the fuel cell (black-to-black) to begin operation Be careful moving the tanks – a leak at this stage means you are “out of gas”!

Comments Fuel cells need to be hydrated in order to run properly, if a fuel cell has been sitting un-used for a long time it may need a soaking rest to re-hydrate. Running the car is the least of the objectives of this exploration Since the fuel cell is used for the electrolysis of water, many people get confused and think that a perpetual motion machine can be created by taking the water waste from the cell and using the electricity generated by the fuel cell to generate more Hydrogen.

Reflection Amount of hydrogen and oxygen produced during electrolysis Source for all this power – the original fuel? Moving the gas tanks to the car – Production of H2? Where?

Activity: Construct a PEM Fuel Cell Fuel Cells July 2012 Activity: Construct a PEM Fuel Cell A small, single cell, PEM fuel cell can easily be constructed Source of hydrogen needed Chemical reaction Fuel cell production + storage Kits: Helpful hint: accordion http://www.fuelcellstore.com/en/pc/catalog/1001FuelCellMini_general.jpg Sustainable Energy Workshop

Activity

Comments Fuel cells need to be hydrated in order to run properly, if a fuel cell has been sitting un-used for a long time it may need a soaking rest to re-hydrate. Try placing it in a plastic bag with a wet towel for a few hours

Section 03: Teaching about Fuel Cells Goal: Exploration of techniques and methods for instruction Curricular Objectives Available Animations Survey of available resources Critique based on current understanding Energy Chain for Fuel Cells Identification of energy input for electrolysis Motivation for Hydrogen economy Available Levels of Instruction

Educational Objectives – Curricular Connections

Discussion: Available Animations

Energy Chain for Fuel Cells Are there associated societal issues associated with fuel cells (power generation &/or propulsion?) Something is missing here ….

Energy Chain for Fuel Cells ?!

Multiple Instructional Levels Exposure/Exploration Process understanding Chemical Reaction Rate of reaction: dependence on pressure, temperature, etc. Load Impact on Cell Efficiency High voltage vs. low voltage applications Activation energy

Activity: Fuel Cell Stack July 2012 Activity: Fuel Cell Stack Exploration of a pressurized fuel cell stack http://www.tekstak.com/TekStak/Images/Parker-Stack.jpg Sustainable Energy Workshop

Activity

Comments

Section 04: Cellular Structure (Batteries) Goal: Relationship between fuel cells & common batteries Battery Construction Battery Chemistry Comparison Fuel Cell as a Stationary Power Generator Fuel Cell: Propulsion Application

Different From a Battery? Fuel Cells July 2012 Redox (Oxidation-Reduction Reaction) Left: http://www.smith.edu/hsc/museum/ancient_inventions/battery1a.JPG Middle: http://images.google.com/imgres?imgurl=http://www.batterymart.com/images/how-batteries-work.jpg&imgrefurl=http://www.batterymart.com/c-how-a-battery-works.html&h=195&w=251&sz=8&hl=en&start=50&um=1&tbnid=kUmVMZIIdGPjEM:&tbnh=86&tbnw=111&prev=/images%3Fq%3DBattery%2Bworks%26start%3D40%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DN Right: http://www.china-manufacturer-directory.com/picture/alkaline-battery-aa-lr6.jpg Baghdad Battery – 250 BC Sustainable Energy Workshop

Lead-Acid Batteries e.g. car batteries, deep-cycle batteries Fuel Cells Lead-Acid Batteries July 2012 (2V per cell) e.g. car batteries, deep-cycle batteries Energy-to-weight ratio very low Energy-to-volume ratio: low But ….Power-to-Weight ratio: LARGE Left: http://www.britannica.com/eb/art/print?id=1333&articleTypeId=1 Right: http://www.offroaders.com/tech/images/lead-acid_battery.jpg RECHARGABLE Sustainable Energy Workshop

NiMH (Nickel-metal hydride) Batteries Fuel Cells July 2012 NiMH (Nickel-metal hydride) Batteries RECHARGABLE e.g. hybrid vehicles Top Left: http://www.nrel.gov/features/08-06_plugin_hybrids.html?print Bottom Left; http://www.cleangreencar.co.nz/page/prius-technical-info Bottom Right: http://www.cleangreencar.co.nz/p/vibrantplanet.com/cleangreencar/1118550814_54343.jpg Lithium-ion batteries are also an option for hybrids Sustainable Energy Workshop

Regenerative Braking – Hybrid Vehicles Fuel Cells July 2012 Regenerative Braking – Hybrid Vehicles Friction brakes dissipate car’s kinetic energy as heat eCorner. The wheel rim (1) remains the same. Beneath is the wheel hub motor (2). Braking is via electronic wedge brake (3). The active suspension (4), like the electronic steering (5), replaces the conventional hydraulic system. Apply the brake ---- Car’s electronics switch Electric Traction Motor to a generator Wheel spins – load applied (generates electricity to charge battery) Reverse torque applied to wheels – slowing the car down Left: http://zebu.uoregon.edu/2001/ph162/l8.html Middle Top: http://www.solarnavigator.net/images/dc_adaptive_motor.gif Top Right: http://www.vdo.com/NR/rdonlyres/22B3BD00-8397-4A32-85D0-7738F9D00A68/0/sv_pp_eCornerschnitt_200608002_zoom.jpg Middle Bottom: http://www.gm-volt.com/wp-content/uploads/2007/02/hybrid_regenerativebraking.jpg Sustainable Energy Workshop

Similarities and Differences Chemical potential energy converted in to Electric potential energy Cellular structure Redox reactions Differences Passage of H2 and O2 thru vs. storage of chemicals in battery Flow battery

Cellular Structure of Fuel Cells July 2012 Cellular Structure of Fuel Cells Batteries in series Left: http://www.makeitsolar.com/images/battery_circuit_series_002.gif (c Johnson Matthey) Middle: http://www.sovereign-publications.com/images/ballard/PEM-fuel-cell-large.jpg Right: http://www.makeitsolar.com/images/battery_circuit_series_002.gif Can do all of the series/parallel experiments that one does with batteries Fuel cells are essentially flow-through batteries Challenge is getting H2 and O2 uniformly to all of the cells Sustainable Energy Workshop

Stationary Power Facility: Stacks Fuel Cells July 2012 Stationary Power Facility: Stacks 5 kW Fuel Cell System, Manufactured by PlugPower, Installed at a USDOD Facility 5 PC 25TM Fuel Cells sited in Anchorage, Alaska (International Fuel Cells, LLC) Top Left: http://physics.nist.gov/MajResFac/NIF/Images/FuelCellBasic.gif Bottom Left: http://en.wikipedia.org/wiki/Image:Fc_diagram_pem.gif Right: http://www.siliconchip.com.au/cms/gallery/article.html?slideshow=0&a=30527&i=7 200-kW + 900,000 BTU heat PAFC (Phosphoric Acid Fuel Cells) Sustainable Energy Workshop

Parts of a PEM Fuel Cell System July 2012 Propulsion System Left: http://us1.webpublications.com.au/static/images/articles/i305/30527_4lo.jpg Right: VW’s HTFC http://techfreep.com/tags/vw/ Automotive Application Volkswagen’s HTFC Sustainable Energy Workshop

Section 06: The Hydrogen Economy Goal: Understand infrastructure issues with fuel cells Definition: Hydrogen Economy Infrastructure Planning Hydrogen Production Methods Hydrogen Delivery Methods Hydrogen Safety Issues

The Hydrogen Economy Hydrogen as a storage medium for energy Fuel Cells July 2012 Hydrogen as a storage medium for energy Problem: Hydrogen does not occur naturally in nature as H2 Left: http://en.wikipedia.org/wiki/Image:Realizing.the.Hydrogen.Economy.chart.gif Right: http://www.emagazine.com/view/?171 Sustainable Energy Workshop

The Hydrogen Economy Infrastructure Fuel Cells July 2012 Infrastructure How does one go about developing a production, delivery and use system for an energy storage medium that is only in its infancy Right: http://www.hydrogen.energy.gov/systems_integration.html Left: http://lh3.ggpht.com/_AVODjjM-COk/SA65LmTW9eI/AAAAAAAAEy0/mvhyLN8LnHM/cartbeforehorse.jpg http://www.hydrogen.energy.gov/systems_integration.html Sustainable Energy Workshop

Hydrogen Production and Delivery Fuel Cells July 2012 Hydrogen Production and Delivery Advantage: Hydrogen is storage medium – Production from a variety of sources Currently: Steam Reforming of Natural Gas Biological Water Splitting Photoelectrochemical Water Splitting Reforming of Biomass and Wastes Solar Thermal Water Splitting Renewable Electrolysis www.sunline.org Community Adoption – Priming the Pump Sustainable Energy Workshop

Fuel Cells July 2012 Hydrogen Storage Hydrogen is not an ‘energy dense’ fuel (need lots to go anywhere) Pressurized Steel and Composite Tanks Hydrogen can cause metals to become brittle (not good!) Metal Hydride H2 is locked in another chemical Chemical reaction releases that metal Micropore Storage Buckyballs & nanoscale methods Left: http://img.alibaba.com/photo/201401300/Hydrogen_Storage_Device.jpg Metal Decorated Nanostructures Sustainable Energy Workshop

The Hydrogen Safety Movie Fuel Cells The Hydrogen Safety Movie July 2012 It’s not what you may think Left: http://science.nasa.gov/headlines/y2003/images/zeolite/hindenberg.jpg Right: http://public.ca.sandia.gov/8700/files/hydroJetFlame.jpg Sustainable Energy Workshop

Section 07: Challenges and Advantages Goal: Listing of Future Directions

Discussion: Synthesis of Fuel Cell

Challenges for PEM Fuel Cells July 2012 Platinum: reduction of amt of material used = reduced cost Wikipedia: 2002 cost was $1,000 per kW Water management Too little --- membrane dries up Too much --- pores blocked, efficiency drops Steady Fuel Supply Controlling amount of incoming gas + pressure Poisoning of the anode by carbon monoxide Temperature control http://en.wikipedia.org/wiki/File:Condensation.jpg This technology is coming out of its infancy ….. Sustainable Energy Workshop