Characterization of Transport Properties in Porous Media of a PEM Fuel Cell

2012 ◽  
Author(s):  
Lalit M. Pant ◽  
Sushanta K. Mitra ◽  
Marc Secanell
Keyword(s):  
Porous Media ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Mass Transport ◽  
Transport Properties ◽  
Experimental Studies ◽  
Effective Diffusivity ◽  
Theoretical Models ◽  
Gas Diffusion ◽  
Fuel Cell Performance

Porous media is an essential part of polymer electrolyte membrane fuel cells (PEMFC). In order to optimize fuel cell performance and reduce catalyst consumption, mass transport in fuel cells needs to be improved. Understanding and modelling of mass transport in porous media of fuel cell (e.g. gas diffusion layer (GDL), micro porous layer (MPL) etc.) requires a knowledge of transport properties like diffusivity, permeability and Knudsen diffusivity. Current research is focused on experimental measurement of transport properties of porous media. A counter-diffusion bridge (Wicke-Kallenbach setup) has been used to estimate permeability, Knudsen diffusivity and effective diffusivity of GDLs and MPLs. The obtained transport properties are used with the recent theoretical models of multicomponent mass transport to estimate transport in fuel cells. The experimental studies show that conventional effective approximations like Bruggeman correlations are highly overpredicting and do not fully account for all the frictional forces in porous media.

Effect of Vibration on the Liquid Water Transport of PEM Fuel Cells

2009 ◽  
Author(s):  
Luis Breziner ◽  
Peter Strahs ◽  
Parsaoran Hutapea
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Transport ◽  
Liquid Water ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Sinusoidal Vibration ◽  
Fuel Cell Performance ◽  
Liquid Water Transport

The objective of this research is to analyze the effects of vibration on the performance of hydrogen PEM fuel cells. It has been reported that if the liquid water transport across the gas diffusion layer (GDL) changes, so does the overall cell performance. Since many fuel cells operate under a vibrating environment –as in the case of automotive applications, this may influence the liquid water concentration across the GDL at different current densities, affecting the overall fuel cell performance. The problem was developed in two main steps. First, the basis for an analytical model was established using current models for water transport in porous media. Then, a series of experiments were carried, monitoring the performance of the fuel cell for different parameters of oscillation. For sinusoidal vibration at 10, 20 and 50Hz (2 g of magnitude), a decrease in the fuel cell performance by 2.2%, 1.1% and 1.3% was recorded when compared to operation at no vibration respectively. For 5 g of magnitude, the fuel cell reported a drop of 5.8% at 50 Hz, whereas at 20 Hz the performance increased by 1.3%. Although more extensive experimentation is needed to identify a relationship between magnitude and frequency of vibration affecting the performance of the fuel cell as well as a throughout examination of the liquid water formation in the cathode, this study shows that sinusoidal vibration, overall, affects the performance of PEM fuel cells.

Transport Phenomena Analysis in Proton Exchange Membrane Fuel Cells

2005 ◽  
Vol 127 (12) ◽  
pp. 1363-1379 ◽  
Author(s):  
Hongtan Liu ◽  
Tianhong Zhou ◽  
Ping Cheng
Keyword(s):  
Experimental Investigation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transport Phenomena ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Transport Processes ◽  
Proton Exchange ◽  
Exchange Membrane

The objective of this review is to provide a summary of modeling and experimental research efforts on transport phenomena in proton exchange membrane fuel cells (PEMFCs). Several representative PEMFC models and experimental studies in macro and micro PEMFCs are selected for discussion. No attempt is made to examine all the models or experimental studies, but rather the focus is to elucidate the macro-homogeneous modeling methodologies and representative experimental results. Since the transport phenomena are different in different regions of a fuel cell, fundamental phenomena in each region are first reviewed. This is followed by the presentation of various theoretical models on these transport processes in PEMFCs. Finally, experimental investigation on the cell performance of macro and micro PEMFC and DMFC is briefly presented.

Design of an Experimental Setup to Study Mass Transport in Micro-Nano Capillaries and Porous Media

2010 ◽  
Author(s):  
Lalit M. Pant ◽  
Marc Secanell ◽  
Sushanta K. Mitra
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Fuel Cells ◽  
Mass Transport ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Experimental Setup ◽  
Convection Diffusion ◽  
Electrolyte Membrane ◽  
Pure Diffusion

Study of gas diffusion is critical in understanding the process of mass transfer in porous media, which is an integral part of polymer electrolyte membrane fuel cells (PEMFCs). An experimental method is presented to study the mass transfer processes in micro-nano capillaries, which is further extended to study the transport in the porous media of fuel cells. A diffusion bridge setup, similar to the one presented by Remick and Geankoplis [1] has been used. The experimental setup facilitates the study of binary and multicomponent mixture transport through micro-nano capillaries and porous media. The setup can perform studies for two cases viz., pure diffusion and convection-diffusion. Using pressure controls in both channels, the pressure gradient across the capillaries is varied to study the convection diffusion process in detail. The results obtained from the study will be used to review various models of mass transport available in literature.

Measurement of a new parameter representing the gas transport properties of the catalyst layers of polymer electrolyte fuel cells

2016 ◽  
Vol 18 (18) ◽  
pp. 13066-13073 ◽  
Author(s):  
Hiroshi Iden ◽  
Atsushi Ohma ◽  
Tomomi Tokunaga ◽  
Kouji Yokoyama ◽  
Kazuhiko Shinohara
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Transport Properties ◽  
Polymer Electrolyte ◽  
Gas Transport ◽  
Polymer Electrolyte Fuel Cells ◽  
Cell Performance ◽  
Fuel Cell Performance ◽  
Catalyst Layers ◽  
Gas Transport Properties

The optimization of the catalyst layers is necessary for obtaining a better fuel cell performance and reducing fuel cell cost.

Effects of Microhydrophobic Porous Layer on Water Distribution in Polymer Electrolyte Membrane Fuel Cells

2013 ◽  
Vol 11 (1) ◽  
Author(s):  
Farzad Ahmadi ◽  
Ramin Roshandel
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Cathode Side ◽  
Two Phase ◽  
Fuel Cell Performance ◽  
Electrolyte Membrane

Performance of polymer electrolyte membrane fuel cells (PEMFC) at high current densities is limited to transport reactants and products. Furthermore, large amounts of water are generated and may be condensed due to the low temperature of the PEMFC. Development of a two-phase flow model is necessary in order to predict water flooding and its effects on the PEMFC performance. In this paper, a multiphase mixture model (M2) is used, accurately, to model two-phase transport in porous media of a PEMFC. The cathode side, which includes channel, gas diffusion layer (GDL), microporous layer (MPL), and catalyst layer (CL), is considered as the computational domain. A multidomain approach has been used and transport equations are solved in each domain independently with appropriate boundary conditions between GDL and MPL. Distributions of species concentration, temperature, and velocity field are obtained, and the effects of MPL on species distribution and fuel cell performance are investigated. MPL causes a saturation jump and a discontinuity in oxygen concentration at the GDL/MPL interface. The effect of MPL thickness on fuel cell performance is also studied. The results revealed that the MPL can highly increase the maximum power of a PEMFC.

scholarly journals Simulation of 3D Porous Media Flows with Application to Polymer Electrolyte Fuel Cells

2013 ◽  
Vol 13 (3) ◽  
pp. 851-866 ◽  
Author(s):  
N. I. Prasianakis ◽  
T. Rosén ◽  
J. Kang ◽  
J. Eller ◽  
J. Mantzaras ◽  
...  
Keyword(s):  
Porous Media ◽  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Model Simulation ◽  
Three Dimensional ◽  
Effective Diffusivity ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cells ◽  
Porous Media Flows ◽  
Media Flows

AbstractA 3D lattice Boltzmann (LB) model with twenty-seven discrete velocities is presented and used for the simulation of three-dimensional porous media flows. Its accuracy in combination with the half-way bounce back boundary condition is assessed. Characteristic properties of the gas diffusion layers that are used in polymer electrolyte fuel cells can be determined with this model. Simulation in samples that have been obtained via X-ray tomographic microscopy, allows to estimate the values of permeability and relative effective diffusivity. Furthermore, the computational LB results are compared with the results of other numerical tools, as well as with experimental values.

CFD Multiphysics Modeling and Performance Evaluation of PEM Fuel Cells

2017 ◽  
Author(s):  
Victor Fontalvo ◽  
Danny Illera ◽  
Humberto Gómez ◽  
Marco Sanjuan
Keyword(s):  
Fluid Dynamics ◽  
Porous Media ◽  
Charge Transfer ◽  
Fuel Cell ◽  
Electrical Potential ◽  
Three Dimensional ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Operational Conditions ◽  
Fuel Cell Performance

Computational Fluid Dynamics (CFD) models allows the three-dimensional simulation of the complex electrochemical, fluid dynamics, and thermodynamic phenomena related to the temperature and pressure distribution in the channels and the porous media than occurs inside the fuel. This work presents a CFD Multiphysics simulation of a PEM Fuel Cell under different operational conditions in their inlet streams. The simulation was done by using COMSOL Multiphysics® software, and it takes into account the mass transfer of gases in the channels, the porous media and the electrochemistry from reactions in a 5 cm2 active area. From the electrochemical perspective, the relationship between the charge transfer and the overpotentials are taken into account by kinetic expressions. In addition, the ohm’s law is applied in conjunction with the charge transfer to describe the conduction of current in the electrodes and electrolytes. Gas diffusion layers (GDL) along with the catalyst layers are modeled as porous media restricting the electrochemical reaction. As the result of different simulation scenarios representing different operational conditions, the characteristic Polarization Curve of the fuel cell, the dependence between the voltage in the cell, and the demanded current by the load are obtained. A reduction in the electrical potential was evidenced due to the reaction activation potential, the ohmic losses due to the electrical resistance of the materials and the concentration losses as a result of deficiencies in the diffusion of the reactants through the porous medium. Currents distributions and water content are analyzed in order to understand the role of temperature, load, and humidity over the fuel cell performance.

scholarly journals Investigation on the sufficiency and uniformity of channel-porous layer flow in PEM fuel cells

2021 ◽  
Author(s):  
Weitong Pan ◽  
Xueli Chen ◽  
Fuchen Wang ◽  
Gance Dai
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Porous Layer ◽  
Scale Up ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Geometrical Parameters ◽  
Fuel Cell Performance ◽  
Layer Flow ◽  
Reactant Conversion

Acting as the reactant distributor, the gas channel (GC)-gas diffusion layer (GDL) assembly is of significance to the PEM fuel cell performance and durability. In this work, an analytical flow model has been developed for the GC-GDL system. Based on the explicit expressions of the channel-porous layer flow structure, the effects of geometrical parameters are clarified and the flow effects including reactant conversion and uniformity are further derived and clarified. Results reveal that with thinner GDL or longer GC, the nonlinear decrease of axial velocity becomes faster and the decrease of transverse velocity turns from linear to nonlinear. Furthermore, the reactant conversion and uniformity are in an opposite relationship and the criterion of flow homogenization in the fuel cells is proposed to make a trade-off. Moreover, the flow non-uniformity is positively correlated with GC length, which gains insights into the fuel cell scale-up.

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