Experimental analysis of a high temperature PEM fuel cell stack

Proton Exchange Membrane Fuel Cells (PEMFC) have many attractive features, including high power density and high efficiency: these are among the reasons why they are considered as a promising clean energy technology for both transportation and stationary application sectors. However, several unsolved technological problems with economic uncertainties have limited their widespread commercialization, such as intolerance to CO and CO2, slow cathode kinetics, liquid water and heat management. Since most of these problems are related to low temperature (≥80 C) operation and to the high relative humidity of reactant gases, consistent research efforts have been directed to the technology of High Temperature PEM (HT-PEM, 100 - 200C, atmospheric pressure and dry conditions). The main differences of High Temperature (HT) PEM fuel cells as compared to Low Temperature (LT) ones are: reduction of CO poisoning at the anode, accelerate reaction kinetics at the electrodes and consistent simplification in water and heat management. However, this kind of cells are still in the developing phase and, to reach rapid commercialization, significant progress is required to produce systems that achieve the optimum balance of cost, efficiency, reliability and durability. Therefore, an accurate experimental characterization of fuel cells in single cell and stack configurations should be performed. This paper presents the experimental characterization of a HT PEM fuel cell stack. The PEMFC stack nominal power is 1000 W (@ 31.5V) and its operating temperature range is 140-160C. The experimental activity has regarded a series of tests in order to measure the performance under various operating conditions, with particular emphasis on temperature and gas mixtures different feeding gas at the Anode side. Results are compared to LT PEM performances in literature.