Predicting the Effect of Gas-Flow Channel Spacing on Current Density in PEM Fuel Cells

1999 ◽  
Author(s):  
Hamid Naseri-Neshat ◽  
Sirivatch Shimpalee ◽  
Sandip Dutta ◽  
Woo-kum Lee ◽  
J. W. Van Zee
Keyword(s):  
Fuel Cell ◽  
Cross Sections ◽  
Diffusion Layer ◽  
Current Density ◽  
Gas Flow ◽  
Channel Model ◽  
Three Dimensional ◽  
Pem Fuel Cell ◽  
Flow Channel ◽  
Straight Channel

Abstract The effects of change in diffusion layer width for constant diffusion layer thickness and constant gas-flow channel width are investigated with a straight channel model of a Proton Exchange Membrane (PEM) fuel cell. A three-dimensional 10-cm long straight channel model of the PEM fuel cell is presented. The geometrical model includes diffusion layers on both the anode and cathode sides and the numerical model couples three-dimensional Navier-Stokes flow with electro-chemical reactions occurring in the fuel cell. Contours of the current density, anode water vapor concentration, anode water activity, water molecules per proton flux, and secondary flow velocity vectors at different cross sections are presented for the two diffusion layer widths. For the particular conditions and properties used for this study, the results show a marked difference between the base case (0.16-cm) and the wide (0.72-cm) diffusion layer. The current density is quite uniform at different axial cross sections and cross-flow sections for the 0.16-cm wide diffusion layer. However, for the 0.72-cm wide diffusion layer, the current density decreases more significantly in the axial direction near the edges of the diffusion layer. Numerical predictions of the water transport between cathode and anode across the width of the MEA show the delicate balance of diffusion and electro-osmosis and their effect on the current distribution along channel.

Three-dimensional model of a 50 cm2 high temperature PEM fuel cell. Study of the flow channel geometry influence

2010 ◽  
Vol 35 (11) ◽  
pp. 5510-5520 ◽  
Author(s):  
Justo Lobato ◽  
Pablo Cañizares ◽  
Manuel A. Rodrigo ◽  
F. Javier Pinar ◽  
Esperanza Mena ◽  
...  
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Three Dimensional ◽  
Pem Fuel Cell ◽  
Flow Channel ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Channel Geometry ◽  
Cell Study ◽  
High Temperature Pem

Lattice Boltzmann Modeling of Water Cumulation at the Gas Channel-Gas Diffusion Layer Interface in Polymer Electrolyte Membrane Fuel Cells

2014 ◽  
Vol 11 (6) ◽  
Author(s):  
Dario Maggiolo ◽  
Andrea Marion ◽  
Massimo Guarnieri
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Vapor Condensation ◽  
Relative Height ◽  
Gas Channel

Several experiments have proved that water in liquid phase can be present at the anode of a PEM fuel cell due to vapor condensation resulting in mass transport losses. Nevertheless, it is not yet well understood where exactly water tends to cumulate and how the design of the gas channel (GC) and gas diffusion layer (GDL) could be improved to limit water cumulation. In the present work, a three-dimensional lattice Boltzmann based model is implemented in order to simulate the water cumulation at the GC–GDL interface at the anode of a PEM fuel cell. The numerical model incorporates the H2–H2O mixture equation of state and spontaneously simulates phase separation phenomena. Different simulations are carried out varying pressure gradient, pore size, and relative height of the GDL. Results reveal that, once saturation conditions are reached, water tends to cumulate in two main regions: the upper and side walls of the GC and the GC–GDL interface, resulting in a limitation of the reactant diffusion from the GC to the GDL. Interestingly, the cumulation of liquid water at the interface is found to diminish as the relative height of the GDL increases.

Experimental Evaluation of Air Flow Effect in Gas Diffusion Layer on PEM Fuel Cell Performance

2008 ◽  
Author(s):  
Yutaka Tabe ◽  
Daisuke Yoshida ◽  
Kazushige Kikuta ◽  
Takemi Chikahisa ◽  
Masaya Kozakai
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Current Density ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Stable Operation ◽  
Local Pressure ◽  
The Cross

This paper investigated the effects of gas and liquid water flow on the performance of a polymer electrolyte membrane (PEM) fuel cell using cells to allow direct observation of the phenomena in the cell and measurements of the local current density and the local pressure loss. The experimental results to compare the separator type indicated the effect of cross-over flow in the gas diffusion layer (GDL) under the lands of serpentine separators on cell performance and the potential of straight channel separator to achieve a relatively-uniform current density distribution. To evaluate the cross-over flow under the land of serpentine separators, a simple circuit model of the gas flow was developed. This analysis showed that slight variations in oxygen concentration caused by the cross-over flow under the land affect the local and overall current density distributions. It was also shown that the establishment of gas paths in the deep layer of GDL by the channels filled with condensed water is effective for stable operation at low flow rates of air in the straight channels.

Effect of Gas Diffusion Layer Surface Wettability Gradient on Water Behavior in a Serpentine Gas Flow Channel of Proton Exchange Membrane Fuel Cell

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Sneha Malhotra ◽  
Sumana Ghosh
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Gas Flow ◽  
Proton Exchange Membrane ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Flow Channel ◽  
Proton Exchange ◽  
Surface Wettability ◽  
Exchange Membrane

Water removal and behavior, in proton exchange membrane fuel cell (PEMFC) gas flow channel has been investigated in this work. Single serpentine gas flow channel has been simulated. Hydrodynamics of water drops in a serpentine channel are studied as a function of nature of gas diffusion layer (GDL) surface wettability. In one case, the surface becomes gradually hydrophobic starting from 90 deg to 170 deg. In this second case, the value of contact angle reduces to 10 deg. A three-dimensional model has been developed by using cfd software. Two different drop of diameter 0.2 mm and 0.4 mm are simulated for all the cases. It is observed that, water coverage is always lesser for a gradual hydrophobic surface. Also at low air velocity and gradual hydrophobic GDL surface results in lesser pressure drop as well as water coverage.

Graduated Resistance to Gas Flow Through a GDL in an Unconventional PEM Stack

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Terry B. Caston ◽  
Kanthi L. Bhamidipati ◽  
Haley Carney ◽  
Tequila A. L. Harris
Keyword(s):  
Fuel Cell ◽  
Current Density ◽  
Gas Flow ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Carbon Paper ◽  
Carbon Cloth ◽  
Oxygen Utilization ◽  
Average Current Density ◽  
Reactant Distribution

The goal of this study is to design a gas diffusion layer (GDL) for a polymer electrolyte membrane (PEM) fuel cell with a graduated permeability and thereby graduating the resistance to flow throughout the GDL. It has been shown that in using conventional materials, the GDL exhibits a higher resistance in the through-plane direction due to the orientation of the small carbon fibers that make up the carbon paper or carbon cloth. In this study, a GDL is designed for an unconventional PEM fuel cell stack where the reactant gases are supplied through the side of the GDL rather than through flow field channels machined into a bipolar plate. The effects of changing in-plane permeability, through-plane permeability, GDL thickness, and oxygen utilization on the expected current density distribution at the catalyst layer are studied. Three different thicknesses and three different utilizations are investigated. It has been found that a thinner GDL with a lower utilization yields a higher current density on the electrode. A quantitative metric to measure uniformity of reactant distribution and the ratio of the standard deviation of the current density to the average current density was introduced, and it was found that while the uniformity of the reactant distribution is independent of thickness of the GDL, it is inversely proportional to utilization.

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