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05/01/2006 10:29 AM . polymer membrane . Same as 3); . Same as 2); . Same as 1) = Costs. In 2002, typical cells had a catalyst content of USD 1000 per kW of electric power output, which is expected, by 2007, to be reduced to USD 30 per kW [1] (http://www.fuelcellcontrol.com/evs19.html) . Ballard's success is a catalyst enhanced with carbon silk with a 30% reduction (1 mg/cm2 to 0.7 mg/cm2) of platinum without reduction in performance (2005)[2] (http:/Awww.fuelcellsworks.com/Supppage2336.html) . The production costs a.c.a MEA (membrane electrode assembly) of the PEM (proton exchange membrane). The Nafion® membrane, -/+ 400,= Euro/m2, followed by the Toyota PEM and 3M PEM membrane are replaced by the ITM Power membrane, resulting in a price of -/+ 4 Euro/m2 (2004). This new membrane is a Hydrocarbon-polymer. One of the bigger companies is using Solupor® (a porous polyethylene film)[3] (http://www.ecn.nl/bct/solupor.en.html) . Water management in (PEMFC's). In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced. If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas "short circuit" where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell. If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to dispose of the excess water are being developed by fuel cell companies. Temperature management. The same temperature must be maintained throughout the cell in order to prevent destruction of the cell through thermal loading. Flow control. Just as in a combustion engine, a steady ratio between the reactant and oxygen is necessary to keep the fuel cell operating efficiently. Durability, lifetime, and special requirements for some type of cells. Stationary applications typically require more than 40,000 hours of reliable operation at a temperature of -35°C to 40°C, while automotive fuel cells require a 5,000 hour lifespan (the equivalent of 150,000 miles) under extreme temperatures. (See: Hydrogen vehicle. Status 2005: lifetime reached.) Automotive engines must also be able to start reliably at -30°C and have a high power to volume ratio (typically 2.5kW per liter). Limited CO tolerance of the anode. Working Name Electrolyte Range t elec. eff. Status emp. Reversible fuel cell Learning kit Up to Blue energy polyethylenemembrane 250KW Research MFC - Biological fuel cell Zinc fuel cell (‘Air' fuel cell) Liquid electrolytes with redox Redox fuel cell shuttle and polymer Research membrane 10 to Cell: 60— AFC - Alkaline fuel Aan under (70% albalinan enliutian Cammoarnial/Dacaarch Name Electrolyte elec. eff. Status Page 3 of 8 Fuel cell - Wikipedia, the free encyclopedia POWs oul oF Ne COR J Fuel cell design issues Types of fuel cells http://en.wikipedia.org/wiki/Fuel_cell