THE INFLUENCE OF PEM THICKNESS ON CELL PERFORMANCE AND PRESSURE DROP IN GAS CHANNELS WITH DISTINCT CROSS-SECTIONS BASED ON CFD

Abstract

Hydrogen is a promising clean energy carrier owing to producing from renewable and low carbon resourcessuch as waste, hydro, wind and solar. Proton exchange membrane fuel cells (PEMFCs) have an encouragingprospect for the future energy source employed in distinct applications such as transportations, portable andstationary power. In PEMFC, eco-friendly electricity is generated from hydrogen and oxygen with only heat andwater as the by-products. The cells constitute various parts including a membrane, bipolar plates with flow channels,catalyst and gas diffusion layers. The changes in the membrane dimensions affect PEMFC efficiency. In the currentwork, a computational model is improved to analyze the influences of membrane thickness on PEMFC performancethrough ANSYS Fluent PEMFC Add-on Module for 0.4, 0.6 and 0.8 V. The channel size of 0.8 x 1 mm (width xdepth) and varying PEM thickness (T = 0.108 mm) from 1/4T to 3/4T are considered. The findings reveal that areduction in the membrane thickness enhances water generation, oxygen consumption and thus PEMFC performanceat the cost of higher pressure loss along the channels. The highest current density of 3.32 A/cm2 is attained having thethickness of T/4 compared to the base configuration (1 x 1 mm channel) having 1.26 A/cm2 current density. Thisconfiguration increases anode and cathode pressure drop by 41.7% and 36.4%, respectively, compared to the base at0.4 V. In addition, the impact of gas channel cross-section on the cell performance is also examined. An increase inthe width of channels from 0.8 to 1.2 mm for a constant depth of 1 mm for T/4 thickness provides 2.96 A/cm2 currentdensity with a considerably decrease in the pressure drop compared to the reference case. It is found that theinnovative configuration with T/4 membrane thickness and 1.2 mm channel width is beneficial to augment thecurrent density of the cell and reduce pressure loss in the channels.