Enhancement of water management in PEM fuel cells

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In the past century, there has been a dramatic climate change due to the greenhouse effect mainly caused by increased levels of carbon dioxide released into the atmosphere. Also, despite public awareness through extensive media coverage, emissions from industry and motor vehicles are still the main cause of air pollution that claims thousands of lives in Canada every year according to Health Canada. The primary cause of both climate change and air pollution is the burning of fossil fuels. In view of these problems, alternative sources of energy must be explored. Proton exchange membrane (PEM) fuel cells have drawn much attention in the last decade as a high-efficiency and low-emission source of energy. However, the performance and cost of the PEM fuel cells must be improved significantly before they can constitute a viable market. One of the major problems of the current PEM fuel cells is water management. The polymer membrane of the PEM fuel cell needs to be well hydrated to maintain proton conductivity. However, excessive water vapor condensation, due to a long operation or large output current, forms micro-droplets that block the access of the reactant gas to the reaction site. The improvement of water management requires the study of droplet formation and liquid water transport in the internal network of the fuel cell. The proposed research program involves the study of three mechanisms: 1) micro-droplet formation on different layers of the membrane electrode assembly (MEA), 2) liquid water transport in the gas diffusion layer (GDL), and 3) droplet agglomeration at the GDL/flow channel interface. To gain better insight into these mechanisms, it is required to determine the effect of interfacial and capillary forces on droplet formation and liquid transport in the PEM fuel cell. Experimental methodologies will be developed under this research program to determine 1) the local interfacial properties of the micro-droplets in the MEA, 2) the wettability of the GDL, and 3) the interfacial properties of the droplets at the GDL/flow channel interface. This work will result in the enhancement of water management in the PEM fuel cells and hence contribute to the strengthening of Canadian fuel cell technology.