A Study of Stirred Tank Reactor Polymer Electrolyte Membrane Fuel Cell Stack Dynamics
نویسندگان
چکیده
A stirred tank reactor design of a polymer electrolyte membrane (PEM) fuel cell was modified and expanded into a stack. Steady-state as well as transient dynamics of the stack at various feed flow rates was examined. Non-uniform distribution of reactants led to differences in individual cell voltages. Instabilities of current and voltages were observed at low feed flow rates, and these could have been due to flooding and limited fuel supply. Starvation of a single cell limited the maximum power that could be generated by the stack. Horizontal surfaces in gas flow channels caused easy build-up of water, leading to a reduction in overall stack performance. In addition, long-term stability of a three-cell stack was demonstrated. A study on water production and removal confirmed that exit gas flow and temperature were important factors in water management in the stack. Over 90% fuel utilization was achieved during control of output current by fuel starvation but periodic instability was observed. Lastly, stainless steel was demonstrated to be unfavorable as a bipolar plate material due to its wetting property.
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