Enhancing Heat Removal and H 2 O Retention Capability of Passive Air-Cooled Polymer Electrolyte Membrane Fuel Cells by Tailoring Cathode Flow-Field Design

Abstract

This paper reports novel cathode flow-field designs for passive typed air-cooled polymer electrolyte membrane fuel cells (PEMFCs) to help alleviate electrolyte dehydration and performance degradation issues under excess dry air supply conditions. The proposed flow-field designs include 7 three-dimensional (3D) patterned designs in addition to a parallel channel configuration equipped with rectangular baffles to control the airflow for more efficient heat removal. The designs were evaluated numerically using 3D, two-phase PEMFC simulations. Compared to a typical parallel flow channel configuration, the proposed flow-field designs show better heat removal and water retention capability. The improvement in single cell voltage was around 13–75 mV at an operating current density of 0.5 A cm −2 , whereas the larger pressure drops around ∆ P = 6.9–317.6 Pa cm −1 were required because of the more complex flow-field configurations compared to the simple straight parallel channel geometry ( ∆ P = 7.4 Pa cm −1 ). This work presents a comprehensive understanding of air-cooled PEMFC operating characteristics under excessive dry air supply conditions and a new design strategy for cathode flow-fields.