Scaleup Effect on Performance of Proton Exchange Membrane Fuel Cell

Abstract

Applications of fuel cells in industries, transportations, power plant, or various electrical devices requires scaling up from a small fuel cell to a larger one with enough power for the need of each device. In this study, two sizes of the proton exchange membrane fuel cells were used. The MEA were scaled up from 5 to 50 cm2 in active areas. The platinum loading was 0.2 mg/cm2 on both cathode and anode sides of each cell. The experimental results gave the maximum power output from 5 and 50 cm2 fuel cells at 1.8 and 14.6 watts, respectively. It was found that the power outputs were not increased in direct proportion to the MEA size when the 5 cm2 cell was scaled up to 50 cm2fuel cell. The 50 cm2fuel cell produced less voltage than 5 cm2 fuel cell at the same current density, especially when it was operated in the medium and high current densities, which were in the ohmic and mass transport loss regions. However, in the activation loss region, the polarization curves of 5 and 50 cm2 were not significantly different. The cell performance of 50 cm2fuel cell decreased because larger area resulted in less homogeneity in catalyst coating, and more water production. The later led to more difficulty in water management in the cell. In addition the less surface flatness in a larger fuel cell can reduce the surface contact leading to lower cell performance. In addition, the effect of operating temperature in a 50 cm2 cell was in the same trend as that in a smaller cell. Therefore, the temperature control for uniformity inside the larger fuel cell is a very important criterion.