Current Distribution in a Polymer Electrolyte Membrane Fuel Cell Under Flooding Conditions

2009 ◽  
Author(s):  
A. Jamekhorshid ◽  
G. Karimi ◽  
X. Li
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Current Distribution ◽  
Current Density ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Average Current Density ◽  
Electrolyte Membrane ◽  
Wide Range ◽  
Average Current

Non-uniform current distribution in polymer electrolyte membrane fuel cells results in local over-heating, accelerated ageing, and lower power output than expected. This issue is very critical when fuel cell experiences water flooding. In this work, the performance of a PEM fuel cell is investigated under cathode flooding conditions. A partially flooded GDL model is proposed to study local current density distributions along flow fields over a wide range of cell operating conditions. The model results show as cathode inlet humidity and/or cell pressure increase the average current density for the unflooded portions of the cell increases but the system becomes more sensitive to flooding. Operating the cell at higher temperatures would lead to higher average current densities and the chance of system being flooded is reduced. In addition, higher cathode stoichiometries prevent system flooding but the average current density remains almost constant.

scholarly journals Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Viktor Johánek ◽  
Anna Ostroverkh ◽  
Roman Fiala ◽  
Andrii Rednyk ◽  
Vladimír Matolín
Keyword(s):  
Mass Spectrometry ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Cell Potential ◽  
Electrolyte Membrane ◽  
Power Load ◽  
Wide Range

The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

Sensitivity of Thermal Transport and Phase-Change in Thin Porous Layers to the Distribution of the Solid Matrix

2013 ◽  
Author(s):  
Vinaykumar Konduru ◽  
Ezequiel Medici ◽  
Jeffrey S. Allen
Keyword(s):  
Fuel Cell ◽  
Mass Transport ◽  
Polymer Electrolyte ◽  
Solid Phase ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Transport Layer ◽  
Solid Matrix ◽  
High Water Content ◽  
Electrolyte Membrane

Understanding the water transport in the Porous Transport Layer (PTL) is important to improve the operational performance of polymer electrolyte membrane fuel cells (PEMFC). High water content in the PTL and flow channel decreases the transport of the gas reactants to the polymer electrolyte membrane. Dry operating conditions result in increased ohmic resistance of the polymer electrolyte membrane. Both cases result in decreased fuel cell performance. Multi-phase flow in the PTL of the fuel cell is simulated as a network of pores surrounded by the solid material. The pore-phase and the solid-phase of the PTL are generated by varying the parameters of the Weibull distribution function. In the network model, the mass transfer takes place in the pore-phase and the bulk heat transfer takes place in the both the solid-phase and liquid phase of the PTL. Previous studies have looked at the thermal and mass transport in the porous media considering the pore size distribution. In the present study, the sensitivity of the thermal and mass transport to the different arrangements of the solid-phase is carried out and the effect of different solid-phase distributions on the thermal and liquid transport in PTL of PEM fuel cell are discussed.

Effect of Operating Conditions on the Water Transport Phenomena at the Cathode of Polymer Electrolyte Membrane Fuel Cell

2009 ◽  
Author(s):  
Sang Hern Seo ◽  
Chang Sik Lee
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Water Transport ◽  
Flow Rate ◽  
Water Droplet ◽  
Polymer Electrolyte Membrane ◽  
Transport Phenomena ◽  
Operating Conditions ◽  
Water Flooding ◽  
Electrolyte Membrane

Water management is very important for polymer electrolyte membrane fuel cell because the fuel cell performance is decreased by flooding phenomena generated by liquid water in the cathode channels. In addition, the proton conductivity and water transport of membrane could become different by hydration contents of membrane. This study is observed water transport phenomena of cathode channels with a polymer electrolyte membrane fuel cell according to various operating conditions. In order to obtain the water images, the transparent fuel cell consists of polycarbonate window of the cathode end plate and gold coated stainless steel as the flow field and current collector of the cathode. To investigate the effects of operating conditions on the water transport, experiments were conducted under various operating conditions such as cell temperature, cathode flow rate and cathode backpressure. As operating time elapsed, it is observed that the water droplet formation, growth, coalescence and removal occurred in the cathode channel. It can be known that the high cathode flow rate prevents water flooding by removal of water in the cathode flow channel. Also, the quantity of water droplet was increased by the high cathode backpressure.

Three dimensional numerical simulation of polymer electrolyte membrane fuel cell

2019 ◽  
Vol 30 (1) ◽  
pp. 427-451
Author(s):  
Yeping Peng ◽  
Ghasem Bahrami ◽  
Hossein Khodadadi ◽  
Alireza Karimi ◽  
Ahmad Soleimani ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Current Density ◽  
Two Phase Flow ◽  
Polymer Electrolyte Membrane ◽  
Phase Flow ◽  
Two Phase ◽  
Content Type ◽  
Electrolyte Membrane

Purpose The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and vehicles. These fuel cells provide a high level of energy efficiency at low temperature without any pollution. The convection inside the cell plays a key role in the electrochemical reactions and the performance of the cell. Accordingly, the transport processes in these cells have been investigated thoroughly in previous studies that also carried out functional modeling. Design/methodology/approach A multi-phase model was used to study the limitations of the reactions and their impact on the performance of the cell. The governing equations (conservation of mass, momentum and particle transport) were solved by computational fluid dynamics (CFD) (ANSYS fluent) using appropriate source terms. The two-phase flow in the fuel cell was simulated three-dimensionally under steady-state conditions. The flow of water inside the cell was also simulated at high-current density. Findings The simulation results suggested that the porosity of the gas diffusion layer (GDL) is one of the most important design parameters with a significant impact on the current density limitation and, consequently, on the cell performance. Originality/value This study was mainly focused on the two-phase analysis of the steady flow in the fuel cell and on investigating the impacts of a two-phase flow on the performance of the cell and also on the flow in the GDL, the membrane and the catalyst layer using the CFD.

High Performance Polymer Electrolyte Membrane Fuel Cell Electrodes

2004 ◽  
Author(s):  
N. Rajalakshmi ◽  
R. Rajini ◽  
K. S. Dhathathreyan
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Operating Conditions ◽  
The Other ◽  
Alternative Methods ◽  
Membrane Electrode ◽  
Fuel Cell Electrodes ◽  
Electrolyte Membrane

Several methods are being attempted to improve the performance of PEM Fuel cell electrodes so that the cost of the overall system can be brought down. The performance can be improved if the utilization of the catalyst in the electrode increases. One of the early successful method was to add a proton conducting polymer, such as NafionR to the catalyst layer. However there is a limit to the amount of NafionR that can be added as too much NafionR affect the gas diffusion. The other method is to increase the surface area of the catalyst used which has also been adequately demonstrated. Alternative methods for providing increased proton conductivity and catalyst utilization are thus of great interest, and a number of them have been investigated in the literature. One method that is being extensively investigated is to introduce the catalyst onto the polymer electrolyte membrane followed by lamination with gas diffusion electrode. In the present work, we have carried out two methods i) screen print the catalyst ink on the NafionR membrane ii) catalyze the NafionR membranes by reducing a suitable platinum salt on the membrane. Standard gas diffusion electrodes were then laminated onto this membrane. The performances of Membrane Electrode Assemblies (MEAs) prepared by these routes have been compared with the commercially available Gore catalysed membrane. It was observed that catalysed NafionR membranes show a better performance compared to the catalyst ink screen printed on the NafionR membrane and commercial Gore membrane under identical operating conditions. However MEAs with Gore membrane give a better performance in the iR region compared to the other MEAs prepared using NafionR membrane. The lesser performance with Gore membrane is probably due to the limitations in the lamination method employed.

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