Experimental Investigation And Optimization Of Proton Exchange Membrane Fuel Cell Using Different Flow Fields

Increasing depletion rate of fossil fuels results in a gap in energy demand-supply soon.In addition,fossil fuels are the main cause of environmental pollution.Therefore,hydrogen fuel cell technologies are the most promising and alternative clean energy source of future.At present,several types of fuel cells are present,but proton exchange membrane fuel cells(PEMFCs)are the most promising technology because of their compact size,high power density,low-temperature operations,low noise,the capability of quick startup and light mass.Bipolar plate of PEMFC proves itself as one of the critical components having a major impact not only on the performance of the cell but also on the cost and industrialization of PEMFC.It is greatly influential to cell performance because the flow field structure decides the flow pattern of the reactants and product,heat and water transfer,and the long-run stability of fuel cell.The work in this thesis focuses on the effects of different kinds of flow field geometric structure on PEMFC performance.There is less literature present on wavy flow field design as compared to the other designs and it needs to be explored more.Hence,this research is focusing on the comparative study of conventional parallel,serpentine,interdigitated and recently introduced wavy flow field designs.In the experiment of this study,based on comparative study of less explored flow fields,the designing of different flow fields and fuel cell assembly are carried out.Insitu experiments for performance test,polarization curves,and electrochemical impedance analysis with different operating conditions are carried out.We analyze the gas flow and transfer and the current density for the structure of five different flow fields and the influence of relative humidity and inlet reactant gases.Serpentine flow field performs much better than other flow fields and shows very high-pressure drop.The performance of both wavy flow fields is much better than conventional parallel flow field and show significant tolerance towards change in relative humidity(RH)%.Moreover,they show less pressure drop and consumes less pumping power as compared to other flow fields.The performance of PEMFC can be improved by increasing RH% and use of pure oxygen instead of air can significantly help to gain high current densities.