Abstract

An essential component in the renewable transformation of power grids in northern Canadian communities is the hydrogen energy storage system (HESS), which provides the necessary power stability for high renewable penetration microgrids. Open-cathode PEM fuel cell (OC-PEMFC) is an important component in a low-cost HESS to convert the stored hydrogen to electricity. However, this type of fuel cell demonstrates temperature-coupled, steady-state and dynamic electrical responses that are significantly different from closed-cathode ones, which creates challenges in the HESS power control and its safe operation.
In this thesis, a reduced-order, dynamic theoretical OC-PEMFC model was developed to predict the electrical and thermal characteristics under varying load conditions. The model was established on the basis of available reduced-order theoretical models with modifications for the open-cathode design. Experiment on an installed OC-PEMFC was performed to obtain its steady-state and dynamic electrical and thermal characteristics, which were further used to estimate the model parameters and to validate the accuracy of the developed model. The validation results demonstrated good accuracy in the estimation of thermal responses; however, the model was unable to accurately simulate the dynamic electrical responses, especially on the voltage undershoots and overshoots from load current fluctuations. An electrode “flooding” ratio was introduced to improve the estimation accuracy for dynamic electrical responses. The modification on the developed model had negligible influences on the accuracy of thermal responses or steady-state electrical response while improved the estimation accuracy for the voltage undershoots and overshoots.