Experimental and Numerical Investigations of Tubular-Shaped Direct Methanol Fuel Cells (DMFCs)

This study focuses on both the numerical and experimental investigations of the novel, passively operated, tubular-shaped, Direct Methanol Fuel Cell (DMFC) as an alternative geometry to the traditional planar-shaped fuel cell. The benefit of the tubular geometry compared to the planar geometry is the higher instantaneous volumetric power density provided by the larger active area, which could be beneficial in applications that require a high instantaneous power while occupying a small volume. First, a two-dimensional, two-phase, non-isothermal model was developed to investigate the steady-state performance and design characteristics of a tubular-shaped, passive DMFC. It was found that a higher ambient temperature improves fuel cell performance, but also increases both methanol and water crossover. Oxygen depletion along the passive air flow channel at the cathode significantly affected the performance and is an important component to consider during designing experimental work. Secondly, a tubular-shaped DMFC frame was built that operated completely passively with methanol solution stored in a central fuel reservoir and external axial channels that allowed passive air flow. The performance of the tubular DMFC in this work represents an 870 % improvement in power density from the previous best, passive, tubular DMFC found in the literature and performed as well as a planar shaped DMFC built from the same MEA.