Chemical Degradation of the Silicone Rubber in Simulated PEMFC Environments

2011 ◽  
Vol 197-198 ◽  
pp. 741-748
Author(s):  
Guo Li ◽  
Jin Zhu Tan ◽  
Jian Ming Gong
Keyword(s):  
Fuel Cell ◽  
Surface Chemistry ◽  
Optical Microscopy ◽  
Silicone Rubber ◽  
Pem Fuel Cell ◽  
Sample Surface ◽  
Proton Exchange ◽  
Attenuated Total Reflection ◽  
Chemical Degradation ◽  
Over Time

The long term stability and durability of gaskets made of silicone rubber in proton exchange membrane fuel cell (PEMFC) has important effect on the sealing and the electric-chemical performance of the fuel cell. In present paper, the time-dependent chemical degradation of a silicone rubber was studied in three simulated PEMFC environments. The test temperature was selected and used at 90°C in this study according to the actual PEM fuel cell operation. Optical microscopy was used to show the topographical changes on the sample surface. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was employed to study the surface chemistry of the gasket material before and after exposure to the simulated PEM fuel cell environments over time. The results show that the weight loss increased with the exposure time for the samples. Optical microscopy reveals that the surface conditions of the samples changed over time from initially smooth to rough, crack appearance and finally crack propagation. The ATR-FTIR results show that the surface chemistry changed significantly via de-crosslinking and chain scission in the backbone for the material over time.

Aging of the Gasket Materials in Simulated PEM Environment and Accelerated Mediums

2012 ◽  
Vol 509 ◽  
pp. 1-9
Author(s):  
Guo Li ◽  
Jin Zhu Tan ◽  
Jian Ming Gong
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Fuel Cell ◽  
Surface Chemistry ◽  
Optical Microscopy ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Attenuated Total Reflection ◽  
Durability Test ◽  
Over Time

Silicon rubber is a potential material for gaskets in proton exchange membrane (PEM) fuel cell. So its long term stability and durability is crucial to the electrochemical performance of fuel cell especially in an acidic, high temperature, humid environment. In present paper, the aging process of silicon rubbers has been studied in one simulated PEM fuel cell medium and two accelerated durability test (ADT) mediums for short time test at 70oC and 90oC, respectively. Effect of exposure time, temperature and exposure medium on aging of silicone rubber is also compared. Weight loss is measured by electronic balance; topographical changes on samples’ surfaces are monitored by optical microscopy; Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was employed to study the surface chemistry of samples before and after exposure over time. The results show that the weight loss increased over time. Surface conditions of samples change over time from initially smooth to rough, crack appearance and finally crack propagation through Optical microscopy. ATR-FTIR results show that the surface chemistry changed significantly via de-crosslinking and chain scission in the backbone for materials over time. The aging degree is severe at high temperature or in high concentration acidic solution over time.

Numerical Simulation of Droplet Emergence and Growth From Gas Diffusion Layers (GDLs) in Proton Exchange Membrane (PEM) Fuel Cell Flow Channels

2018 ◽  
Author(s):  
Jingru Benner ◽  
Mehdi Mortazavi ◽  
Anthony D. Santamaria
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Gas Diffusion Layers ◽  
Diffusion Layers ◽  
Flow Channels ◽  
Exchange Membrane ◽  
Over Time

Liquid water management is critical for Proton Exchange Membrane (PEM) fuel cell operation, as excessive humidity can lead to flooding and cell performance degradation. Water is produced in the cathode catalyst layer during the electrochemical reaction. If reactant gas streams become saturated, liquid water forms and must travel through anode and cathode Gas Diffusion Layers (GDLs) to reach flow channels for removal. Understanding the dynamic behavior of the droplet is critical to improve water removal strategies for PEM fuel cells. In this study a 3D, transient, two-phase model based on the Volume of Fluid (VOF) method was developed to study a single droplet in the gas channel. The formation, growth, and breakup of the droplet is tracked numerically and analyzed. The pressure drop across the droplet is monitored over time and compared with theoretical analysis. The droplet size and shape change over time for two different pore sizes are compared. The impact of various gases including air, helium, and hydrogen on droplet dynamics is presented. The viscous force and pressure force on the droplet and the drag coefficient are calculated.

Degradation of Gasket Materials in a Simulated Fuel Cell Environment

2006 ◽  
Author(s):  
Jinzhu Tan ◽  
Y. J. Chao ◽  
Woo-Kum Lee ◽  
C. S. Smith ◽  
J. W. Van Zee ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Surface Chemistry ◽  
Ftir Spectroscopy ◽  
Optical Microscopy ◽  
Polymer Electrolyte Membrane ◽  
Strain Analysis ◽  
Accelerated Aging ◽  
Chain Scission ◽  
Attenuated Total Reflection ◽  
Simulated Fuel

A Polymer Electrolyte Membrane (PEM) fuel cell stack requires elastomeric gaskets in each cell to keep the reactant gases within their respective regions. If any gasket degrades or fails, the reactant gases (O2 and H2) can leak overboard or mix with each other directly during operation or during standby, and affect the overall operation and performance of the fuel cell. The degradation of four commercial gasket materials was investigated in a simulated fuel cell environment in this study. In an effort towards predicting lifetime of fuel cells, two solutions and two temperatures were used in the short-term, accelerated aging tests. Bend-strip environment crack resistance tests were performed on samples with various bend angles. Weight loss was monitored and surface structure changes were examined using optical microscopy on the samples exposed to the simulated fuel cell environment for selected periods of time. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy was employed to study surface chemistry of the gasket materials before and after exposure to the simulated fuel cell environment over time. Stress and strain analysis was conducted using finite element method (FEM) to quantify the stress/state in test samples. The test results reveal that two silicone materials were degraded significantly while the other two did not show much degradation up to 42 weeks exposure to the simulated fuel cell environment. Optical microscopy and ATR-FTIR spectroscopy analysis indicate that the surface chemistry altered gradually via mechanisms involving de-cross linking and chain scission in the backbone. From experimental and numerical results, it is concluded that there is an interaction between chemistry and stress that appears to accelerate the degradation of the gasket materials in fuel cell environment.

scholarly journals An Artificial Intelligence Solution for Predicting Short-Term Degradation Behaviors of Proton Exchange Membrane Fuel Cell

2021 ◽  
Vol 11 (14) ◽  
pp. 6348
Author(s):  
Zijun Yang ◽  
Bowen Wang ◽  
Xia Sheng ◽  
Yupeng Wang ◽  
Qiang Ren ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Activation Function ◽  
Proton Exchange ◽  
Cell Performance ◽  
Short Term ◽  
Degradation Behaviors ◽  
Hidden Layer ◽  
Exchange Membrane

The dead-ended anode (DEA) and anode recirculation operations are commonly used to improve the hydrogen utilization of automotive proton exchange membrane (PEM) fuel cells. The cell performance will decline over time due to the nitrogen crossover and liquid water accumulation in the anode. Highly efficient prediction of the short-term degradation behaviors of the PEM fuel cell has great significance. In this paper, we propose a data-driven degradation prediction method based on multivariate polynomial regression (MPR) and artificial neural network (ANN). This method first predicts the initial value of cell performance, and then the cell performance variations over time are predicted to describe the degradation behaviors of the PEM fuel cell. Two cases of degradation data, the PEM fuel cell in the DEA and anode recirculation modes, are employed to train the model and demonstrate the validation of the proposed method. The results show that the mean relative errors predicted by the proposed method are much smaller than those by only using the ANN or MPR. The predictive performance of the two-hidden-layer ANN is significantly better than that of the one-hidden-layer ANN. The performance curves predicted by using the sigmoid activation function are smoother and more realistic than that by using rectified linear unit (ReLU) activation function.

3-D Model of Proton Exchange Membrane Fuel Cells

2000 ◽  
Author(s):  
Tianhong Zhou ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Three Dimensional Model ◽  
Chemical Reaction Kinetics ◽  
Fuel Cell Performance ◽  
D Model

Abstract A comprehensive three-dimensional model for a proton exchanger membrane (PEM) fuel cell is developed to evaluate the effects of various design and operating parameters on fuel cell performance. The geometrical model includes two distinct flow channels separated by the membrane and electrode assembly (MEA). This model is developed by coupling the governing equations for reactant mass transport and chemical reaction kinetics. To facilitate the numerical solution, the full PEM fuel cell was divided into three coupled domains according to the flow characteristics. The 3-D model has been applied to study species transport, heat transfer, and current density distributions within a fuel cell. The predicated polarization behavior is shown to compare well with experimental data from the literature. The modeling results demonstrate good potential for this computational model to be used in operation simulation as well as design optimization.

The Effect of Inlet Parameters on Fluid Flow and Cell Performance at Cathode of a Proton Exchange Membrane Fuel Cell

2010 ◽  
Vol 7 (4) ◽  
Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar
Keyword(s):  
Reynolds Number ◽  
Fuel Cell ◽  
Power Density ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Exchange Membrane ◽  
Oxygen Mole Fraction

In this study, the fluid flow and cell performance in cathode side of a proton exchange membrane (PEM) fuel cell were numerically analyzed. The problem domain consists of cathode gas channel, cathode gas diffusion layer, and cathode catalyst layer. The equations governing the motion of air, concentration of oxygen, and electrochemical reactions were numerically solved. A computer program was developed based on control volume method and SIMPLE algorithm. The mathematical model and program developed were tested by comparing the results of numerical simulations with the results from literature. Simulations were performed for different values of inlet Reynolds number and inlet oxygen mole fraction at different operation temperatures. Using the results of these simulations, the effects of these parameters on the flow, oxygen concentration distribution, current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also shows that current density and power density of the PEM fuel cell increases with increasing operation temperature. It is also observed that increasing the inlet oxygen mole fraction increases the current density and power density.

Experimental Results of a PEM System Operated on Hydrogen and Reformate

2008 ◽  
Vol 5 (1) ◽  
Author(s):  
M. Minutillo ◽  
E. Jannelli ◽  
F. Tunzio
Keyword(s):  
Fuel Cell ◽  
Natural Gas ◽  
Large Scale ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Cell Performance ◽  
Pure Hydrogen ◽  
Test Bed ◽  
Fuel Cell Performance

The main objective of this study is to evaluate the performance of a proton exchange membrane (PEM) fuel cell generator operating for residential applications. The fuel cell performance has been evaluated using the test bed of the University of Cassino. The experimental activity has been focused to evaluate the performance in different operating conditions: stack temperature, feeding mode, and fuel composition. In order to use PEM fuel cell technology on a large scale, for an electric power distributed generation, it could be necessary to feed fuel cells with conventional fuel, such as natural gas, to generate hydrogen in situ because currently the infrastructure for the distribution of hydrogen is almost nonexistent. Therefore, the fuel cell performance has been evaluated both using pure hydrogen and reformate gas produced by a natural gas reforming system.

Theoretical Analysis on the Autothermal Reforming Process of Ethanol as Fuel for a Proton Exchange Membrane Fuel Cell System

2006 ◽  
Vol 4 (4) ◽  
pp. 468-473 ◽  
Author(s):  
Alessandra Perna
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Autothermal Reforming ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Hydrogen Yield ◽  
Fuel Cell System ◽  
Exchange Membrane

The purpose of this work is to investigate, by a thermodynamic analysis, the effects of the process variables on the performance of an autothermal reforming (ATR)-based fuel processor, operating on ethanol as fuel, integrated into an overall proton exchange membrane (PEM) fuel cell system. This analysis has been carried out finding the better operating conditions to maximize hydrogen yield and to minimize CO carbon monoxide production. In order to evaluate the overall efficiency of the system, PEM fuel cell operations have been analyzed by an available parametric model.

Pore Structure Modeling of Flow in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

2010 ◽  
Author(s):  
Zhongying Shi ◽  
Xia Wang
Keyword(s):  
Fuel Cell ◽  
Pore Structure ◽  
Proton Exchange Membrane ◽  
Cell Model ◽  
Transport Phenomena ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Structure Model ◽  
Exchange Membrane

The gas diffusion layer (GDL) in a proton exchange membrane (PEM) fuel cell has a porous structure with anisotropic and non-homogenous properties. The objective of this research is to develop a PEM fuel cell model where transport phenomena in the GDL are simulated based on GDL’s pore structure. The GDL pore structure was obtained by using a scanning electron microscope (SEM). GDL’s cross-section view instead of surface view was scanned under the SEM. The SEM image was then processed using an image processing tool to obtain a two dimensional computational domain. This pore structure model was then coupled with an electrochemical model to predict the overall fuel cell performance. The transport phenomena in the GDL were simulated by solving the Navier-Stokes equation directly in the GDL pore structure. By comparing with the testing data, the fuel cell model predicted a reasonable fuel cell polarization curve. The pore structure model was further used to calculate the GDL permeability. The numerically predicted permeability was close to the value published in the literature. A future application of the current pore structure model is to predict GDL thermal and electric related properties.

scholarly journals Modeling a Distributed Power Flow Controller with a PEM Fuel Cell for Power Quality Improvement

2018 ◽  
Vol 8 (1) ◽  
pp. 2585-2589 ◽  
Author(s):  
J. Chakravorty ◽  
J. Saraswat ◽  
V. Bhatia
Keyword(s):  
Fuel Cell ◽  
Power Quality ◽  
Power Flow ◽  
Electrical Power ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Distributed Power ◽  
Flow Controller ◽  
Distributed Power Flow ◽  
Power Flow Controller

Electrical power demand is increasing at a relatively fast rate over the last years. Because of this increasing demand the power system is becoming very complex. Both electric utilities and end users of electric power are becoming increasingly concerned about power quality. This paper presents a new concept of distributed power flow controller (DPFC), which has been implemented with a proton exchange membrane (PEM) fuel cell. In this paper, a PEM fuel cell has been simulated in Simulink/MATLAB and then has been used in the proposed DPFC model. The new proposed DPFC model has been tested on a IEEE 30 bus system.

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