6Classification of materials for BPs used in PEM fuel cell : Non-metal : Non-porous graphite platesMetals : Metal platesComposites : - Metal based- Carbon based :- Thermoplastics- Thermosets
7Requirements for Bipolar Plates : Electrical conductivity :- DOE (the U.S.Department of Energy) > 100 S/cm- F.N.Büchi ≥ 10 S/cm(Development of a Bipolar Element for PE- fuel cell, demonstration in a 6 kW stack)- B.W.Choi ≥ 2.5 S/cm (higher than gas diffusion electrode)(J.Hydrogen energy 21 (1996))
8The BPs have the following functions to perform : To distribute the fuel and oxidant within thecell.To facilitate water management within the cell.To separate individual cells in the stack.To carry current away from the cell.- To facilitate heat management.
9Properties of BP :Electrical conductivity : plate resistance 0.01 cm 2Thermal conductivity : as high as possibleHydrogen/gas permeability : 10-4 cm3/scm2Corrosion resistance : corrosion rate mA/cm2Compressive strength : 22 lb/in2Density : 5 gm/cm2
16Discussion and Conclusion : - Add carbon fiber to improve the conductivity of ABS composites.- The effect of content and composition of fillers and the incorporation of fillers including the length of carbon fiber on the electrical properties of polymer composite were studied.
17References:(1) A. Hermann, T. Chaudhuri and P. Spagnol (2005), “Bipolar plates for PEM fuel cells : A review”, International Journal of Hydrogen Energy, 30,(2) H-C. Kuan, C-C. M. Ma, K. H. Chen and S-M. Chen (2004), “Preparation, electrical, mechanical and thermal properties of composite bipolar plate for a fuel cell”, Journal of Power Sources, 134, 7-14.(3) W. Thongruang, R. J. Spontak and C. M. Balik (2002), “Bridged double percolation in conductive polymer composites: an electrical conductivity, morphology and mechanical property study”, Polymer, 43,