Effect of Compression Thickness on Performance of Gas Diffusion Layer of Direct Methanol Fuel Cells

Yong-Sheen Hwang, Hoon Choi, Gu Young Cho, Yoon Ho Lee, Suk-won Cha

This study considers the performance of a direct methanol fuel cell (DMFC) unit for the various compression ratios of a gas diffusion layer (GDL) on the cathode side. A performance of fuel cells is significantly influenced by the compression ratio of the GDL. The compression ratio of the GDL can be directly controlled by the concentration compression force at the central area of the cell and gasket thickness. The balancing of the compression ratio is an important factor to increase the unit cell performance of DMFCs. In this study, the performance test of the unit cell for varying compression ratio of a GDL on the cathode side is carried out. We describe how the compression ratio affects the stack performance by the variation of compression force for two different kinds of current collectors, which directly compresses the central area of the unit cell with varying gasket thickness. This study also suggests a method to show the effect of mass transport loss by amplitude of voltage fluctuation and the unit cell relationship between the pressure drop information and the peak power of the unit cell.