Improvement of performance of polymer electrolyte fuel cell due to addition of micro-grooves as water removal mechanism

Abstract

Although polymer electrolyte fuel cells (PEFCs) have become commercially available, many problems remain to further improve the performance of PEFC and to popularize PEFCs. Water management in PEFC is closely related to cell performance. At high current density, generated water accumulates in gas diffusion layer and in gas channels of cathode, and the excessive water obstructs oxygen transport. The cell performance greatly decreases by blocking the oxygen transport. In order to improve the cell performance, it is necessary to remove effectively the generated water. In this study, to improve the water management in gas channels, novel gas channel with micro-grooves, which are manufactured inside gas channel walls, is adopted. The generated water from gas diffusion layer is removed through the micro-grooves to opposite-side of gas channel by the forces of capillary and shearing generated by air flow. The performance of the PEFC with and without micro-grooves was examined in various experimental conditions. Therefore, the cell performance was examined by changing the cell temperature, relative humidity of gas and air velocity. As the result, it was shown that the PEFC with micro-grooves showed higher performance than the conventional PEFC without grooves. Especially, the value of maximum current density was increased by about 23% when air velocity is 8.0m/s.

Keywords

• polymer electrolyte fuel cell
• micro-grooves
• water management
• flooding
• gas channel