Introduction to fuel cells Introduction to fuel cells History of fuel cell Cee en trae Rennes Nee uc emt Re] whore nie | Seles ac 4 Applications of fuel cellsOBJECTIVES Upon completion of this period, you would be able to know 5 i A 2 A 2 2 Introduction to fuel cells Difference between battery and fuel cell eRe ke et Mae Ro uel el RRR kc Advantages and disadvantages of fuel cells Applications of fuel cellsbtbegere tt copii eel hy © A fuel cell by definition is an electric cell, which, unlike storage cells can be continuously fed to a fuel so that the electrical power output is sustained indefinitely (Connihan, 1981). © They convert hydrogen, or hydrogen-containing fuels, directly into electrical energy plus heat through the electrochemical reaction of hydrogen and oxygen into water. © The process is that of electrolysis in reverse. neem + © Because hydrogen and oxygen gases are electrochemically converted into water, fuel cells have many advantages over heat engines. © These include high efficiency, virtually silent operation and, if hydrogen is the fuel, there are no pollutant emissions. © If the hydrogen is produced from renewable energy sources, then the electrical power produced can be truly sustainable. © The two principle reactions in the burning of any hydrocarbon fuel are the formation of water and carbon dioxide. As the hydrogen content in a fuel increase, the formation of water becomes more significant, resulting in proportionally lower emissions of carbon dioxide. Wood Coal Oil Natural Hydrogen gas Fig 1: Comparison of fluids© As fuel use has developed through time, the percentage of hydrogen content in the fuels has increased. It seems a natural progression that the fuel of the future will be 100% hydrogen. Difference between battery and fuel cell Battery Fuel Cell Ithas stored electro-chemical | In this the fuel and oxidizer which energy within its container. | are needed for the electrochemical reaction are stored external to the container and fed whenever needed. After discharging it needs It needs no recharging. recharging. +> PAGE END --History of fuel cell 1801.., Humphry Dawy demonstrates} the principle of what become fuel cells. 1839 William Grove invents the 1889... Charles Langer and Ludwing Mond develop Grove's invention and name} the fuel cell. 019508 General Electrical invents the proton exchange membrane fuel cell. Francis Bacon demonstrates a 5 kW alkaline fuel cell. ‘Gas battery’ the first fuel cell. 1960s NASA first uses fuel cells in space missions.1970s... The oil crisis prompts the developments of alternative energy technologies including PAFC. . 1980s US Navy uses fuel cells in submarines. 1990s... Larges stationary : DS] fuel cells are developed for commerical and industrial locations. . 2007 ~ Fuel cells begin to be sold commercially as APU and for stationary] backup power. 2008 ... Honda begins Ne Pe leasing the FCX Clarity fuels cell electric vehicle. . 2009 Residential fuel cell micro-CHP units SE become commercially available in Japan. Also thousands of portable fuel cell battery chargers are sold.2013... The Toyota FCV concept, unveiled at the 2013 Tokyo Motor Show, is a practical concep! of the hydrogen fuel cell vehicle Toyota plans to launch around 2015, -- PAGE END --° jo & > Oxidation ‘Bxces products out yao = Water Corre) 7 Fig 2: Schematics of fluid cell © The main components ofa cell are © Anode (Fuel electrode) © Cathode (oxidant electrode) © Electrolyte © Container © Separators ® Sealing © Fuel supply © Oxidizer © Fuel Cell is an electrochemical device, in which the chemical energy of the fuel is converted directly into electrical energy. © The chemical energy is the free energy of the reactants used. © This conversion takes place at constant temperature and pressure. © The basic features of the fuel cell are that the fuel and its oxidant are combined (mixing) in the form of ions rather than neutral molecules. © The fuel gas diffuses through the anode and is oxidized, thus releasing electrons to the external circuit. © The oxidizer diffuses through the cathode and is reduced by the electrons that have come from the anode by way of the external circuit.© The fuel cell is a device that keeps the fuel molecules from mixing with the oxidizer molecules, permitting, however, the transfer of electrons by a metallic path that may contain a load in external circuit. © In the available fuels, hydrogen has so far given the most promising results, although cells consuming coal, oil or natural gas would be economically much more useful for large scale applications. © Some of the possible reactions are Fuel Chemical reaction Voltage Hydrogen-Oxygen 2H, +0, > 2H,0 1.23 V Hydrazine N,H, +0, > 2H,0+N, 1.56 V Carbon (Coal) C+0, >Co, 1.02 V Methane CH, +20, > CO, +2H,0 1.05 V © The fuel cell should have the following characteristics © Itshould have high energy conversion efficiency. © |tshould produce low chemical pollution. ® Itshould be flexible to choose any fuel. ® Itshould have cogeneration capability and rapid load response. ++ PAGE END --°Q Efficient and simple energy converter. Compact, simple, noiseless and do not have moving parts. Highest conversion efficiency of 88 to 97%. Available in wide range of sizes from 5 kW to 10 MW. Can be used as a power source for domestic, commercial, transport, agricultural, industrial and military applications. Less emission products than conventional thermal or diesel power plants. Wide range of fuels such as natural gas, gasified coal, methanol, hydrogen can be used. No need of electrical power supply for charging. Power supply from fuel cell power plants has high operational flexibility. Power flow can be changed rapidly. ° ° ° High initial cost. Low service life. Problem of refilling in vehicles. -- PAGE END --Transition from forklifts to cars Industrial ‘Automotive be eee Cee mes ig Bi © Used as a substitute for storage batteries and primary cells for higher kW and AH (Ampere-Hour) ratings. © Areplacement for IC engines in tractors, automobiles etc., © They can be used as a source of electrical power for remote installations, ships, submarines, emergency supplies and utility power plants. -- PAGE END --NOT Og Ree el RRO} Introduction to fuel cell Difference between battery and fuel cell Dre Rete] eo & & © fet ane Ren aed dele Kl fuel cell oo eee Rene R eee eR cells Applications of fuel cellsChoose the correct answer : 1. A fuel cell is used to. a. Store electrical energy b. Convert chemical energy to electrical energy through a turbine Ans c. Convert chemical energy directly to electrical energy d. All of the above 2. The conversion efficiency of a fuel cell is a. Very high, as 88% to 97% b. Very low, as 15% to 20% Ans c. Same as thermal power plants d. None of the above 3. The net reaction in the fuel cell produces a. Burnt fuel and spent oxidants b. Electrical energy, water and heat Ans c. Lot of smoke d. None of the above -- PAGE END --Sel MoM Roe A) NOL We oe ROR ol Differentiate between a battery and a fuel cell. What are the advantages and disadvantages of fuel cells @