Research on Different Design of Plane Flow Fields about Intersection Node in PEMFC

Abstract

Because flow field design is an effective method for improving the performance of proton exchange membrane fuel cells, some novel flow fields have been proposed to improve mass transportation in the horizontal plane using numerical methods. Different geometrical characteristics in the horizontal plane, such as the intersection-node coverage area, intersection form, and intersection-node distribution, have been used to discuss their effects on cell performance. The simulation results were obtained from nine cases. According to the calculations, introducing a crossover node could increase the current density by up to 26%. The simulation results elucidated that expansion of the reaction area facilitates oxygen diffusion. Forced convection was induced by an inclined channel, which increased the reactant concentration in the downstream region. Therefore, the uniformity of the current density also increased. The flow rate of the gas was affected by the symmetrical mode. Among them, high gas flow velocities were more easily observed in a flow field with a centrally symmetric distribution node. Proton exchange membrane fuel cells are a promising energy conversion device for a wide range of applications. It can directly convert chemical energy into electrical energy. There is one key component in the fuel cell, named the bipolar plate. On them, there are channels with grooves formed by machining; comprehensive performances of the fuel cells are profoundly determined by the structure and distribution of these channels. Therefore, rational design of the flow field is an effective way to improve the fuel cell performance. If the channels are intersected by each other, the intersection nodes will be generated. That is, the structure of the flow field will be changed by introducing different intersection nodes in terms of coverage area, intersection form, and distribution. The purpose of these measures is to increase the residence time of the gas in the flow field. Therefore, this study will introduce the reader to how the performance of the fuel cell is affected by the flow field with intersection nodes.