281604 Dynamic Studies of a Polymer Electrolyte Membrane Fuel Cell (PEMFC)
Polymer electrolyte membrane fuel cells (PEMFCs) used in the commercial applications should operate efficiently in the face of disturbances such as change in the load, feed composition, etc. and malfunctions such as flooding, drying, starvation of reactants, etc. A dynamic model can be used for developing effective control strategies to maintain the efficiency of healthy as well as faulted cells under changing operating conditions .
Though many steady state models are available in the open literature, detailed dynamic models with experimental validation are few in number. In this work, a detailed two-dimensional two-phase dynamic model of a PEMFC is developed. Both anode and cathode catalyst layers are modeled using spherical agglomerate characterization. The model includes mass conservation equations for the chemical species in the flow channel, gas diffusion layer (GDL), microporous layer (MPL), and the catalyst layer (CL). In addition, conservation of charged species is modeled in the GDL, MPL, and CL. As the liquid water plays a crucial role in the PEMFCs, the effect of liquid water is modeled in all the layers. The transport of liquid water through polymer membrane is modeled considering electro-osmotic drag and back-diffusion. The dynamic model is validated with the transient data generated from an in-house cell by changing various operating conditions. The validated model is utilized to study dynamics of various process variables under normal and faulted operation of the cell. An in-situ measurement of these variables is very difficult, if not impossible, with current state-of-the-art technology. The presentation will include a number of key observations that can help to improve the operational efficiency of the PEMFCs under changing operating conditions.