Combination effects of flow field structure and assembly force on performance of high temperature proton exchange membrane fuel cells

Abstract

In this work, a three-dimensional, steady state model was developed by combining mechanical equations, Navier-stokes equation, Maxwell-Stefan equation, and Butler-Volmer equation. This model was used to investigate the influences of flow field structure and assembly force on porosity distribution in gas diffusion layer (GDL), species distribution in GDL, and current density distribution in GDL and membrane by extracting uneven porosity in the GDL from mechanical calculation equation to put in mass transfer calculation and electrochemical calculation equation as the known data. The optimum assembly prestress and optimum flow field structure were achieved. The results show combined effect of the assembly force and flow field makes the uneven porosity distribution and remarkable lateral current in the GDL; the channel width/ rib width ratio of flow field has significant effects on the performance of the high temperature proton exchange membrane fuel cells (HT-PEMFC). These results provide the potential to promote the performance and application of HT-PEMFC.

Impacts of Separator Thickness on Temperature Distribution and Power Generation Characteristics of a Single PEMFC Operated at Higher Temperature of 363 and 373 K

“…The high-temperature PEMFC (HTPEMFC) characteristics have been investigated recently at temperatures over 373 K [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. However, many studies have focused on the R&D of new materials, e.g., membranes and catalysts [7][8][9][10][11][12][13].…”

“…The review reported a comparison of performances among PEMs made of polybenzimidazoles, sulphonated polyether ether ketones and pyridine-based materials operated at high temperatures above 373 K, concluding that it is necessary to perform careful multi-physics modeling of PEM in order to improve H 2 O and thermal management [13]. A numerical study analyzed the distribution of the current density, O 2 and H 2 O concentrations when the assembly pressure was changed [14]. The power generation characteristics were investigated using polarization and power curves and by changing the membrane thickness [15].…”

“…Regarding the separator, the numerical investigation on the impacts of the cross-sectional area shape of the gas flow channel on the distributions of H 2 andO 2 concentrations in the flow channel and the distribution of the current density on PEM at 453 K were reported [25]. In addition, the impacts of the rib and channel sizes of the separator on the power generation characteristics and the mass concentration distributions in HTPEMFC were investigated numerically [14,26], showing that a high current density can be obtained under the channel with a small channel-to-rib ratio, while a high channel-to-rib ratio could cause high current density appearances under the rib [26]. However, the impacts of the separator thickness, which influences the weight, volume and cost of PEMFC stack system, on not only heat and mass transfer phenomena but also power generation characteristics have not been reported yet.…”

Impact of Separator Thickness on Temperature Distribution in Single Polymer Electrolyte Fuel Cell Based on 1D Heat Transfer

“…Focused on the research to understand the heat and mass transfer characteristics in HTPEFC, some numerical studies have reported that the temperature-driven H 2 O transport in cathode GDL [15], optimization of electrode thickness to obtain higher performance without high cost [16], assessment of mass transport effect on the performance by 3D multi-physics modeling [17], optimization of GDL focusing the thickness of porosity by non-isothermal 3D model [18] and dynamic simulation for start-up process by non-isothermal 3D model [4]. Some numerical studies [19] [20] [21] have reported analysis on separators to optimize a gas channel considering the widths of top and bottom, e.g. cross-sectional area with a trapezium shape [19], the investigation of power generation performance, reactant and H 2 O saturation distribution using oriented-type flow channels with porous-blocked baffles [20], and the impact of the ratio of channel width to rib width on the performance and mass distribution in the cell [21].…”

Performance Analysis and Optimization of a High-Temperature PEMFC Vehicle Based on Particle Swarm Optimization Algorithm

“…At present, the research on HT-PEMFCs mainly includes membrane material [ 17 , 18 , 19 , 20 , 21 , 22 ], structure design [ 23 ], parameter study [ 24 ], and performance optimization [ 25 ]. Yang et al [ 26 , 27 ] studied the high-temperature proton exchange membrane (PEM) in order to improve the performance of the PEMFC at high temperature.…”