scholarly journals The Reactant Concentration Simulation at Catalyst Membrane Interface of a MICRO PEM Fuel Cell

2014 ◽  
Vol 9 (1) ◽  
pp. 1-17
Author(s):  
Sean Goudy ◽  
S. O. Bade Shrestha ◽  
Iskender Sahin

Modeling is increasingly widely used to optimization, improvement and cost reduction efforts of the fuel cell technology. Although there are many computational models in literature that describe the behavior of Polymer Electrolyte Membrane (PEM) fuel cell, there is a only few models that simulates the catalyst surface concentration of reactant gases at the catalyst-membrane layer interface. A modeling of a PEM fuel cell is presented to determine both the bulk reactant concentrations and the catalyst surface concentrations at the catalyst layer-membrane layer interface. The results suggest that the reactant deficiencies experienced at high current densities are localized to the catalyst surface. However, the bulk concentration of reactant is not zero, and, in most cases, the bulk concentration of the reactant gases is significantly greater than zero. In actuality, it is the catalyst surface, which is being depleted of reactant, and, at the limiting current density, the surface concentrations of reactant gases are zero. This treatment develops explicitly link between the fuel cell overpotentials and the movement of reactants. DOI: http://dx.doi.org/10.3126/jie.v9i1.10662Journal of the Institute of Engineering Vol. 9, No. 1, pp. 1–17

2019 ◽  
Vol 41 (1) ◽  
pp. 733-740 ◽  
Author(s):  
Ryosuke Ichikawa ◽  
Yutaka Tabe ◽  
Takemi Chikahisa

Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar

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.


2021 ◽  
Vol 9 ◽  
Author(s):  
Andrei Kulikovsky

Impedance of all oxygen transport processes in PEM fuel cell has negative real part in some frequency domain. A kernel for calculation of distribution of relaxation times (DRT) of a PEM fuel cell is suggested. The kernel is designed for capturing impedance with negative real part and it stems from the equation for impedance of oxygen transport through the gas-diffusion transport layer (doi:10.1149/2.0911509jes). Using recent analytical solution for the cell impedance, it is shown that DRT calculated with the novel K2 kernel correctly captures the GDL transport peak, whereas the classic DRT based on the RC-circuit (Debye) kernel misses this peak. Using K2 kernel, analysis of DRT spectra of a real PEMFC is performed. The leftmost on the frequency scale DRT peak represents oxygen transport in the channel, and the rightmost peak is due to proton transport in the cathode catalyst layer. The second, third, and fourth peaks exhibit oxygen transport in the GDL, faradaic reactions on the cathode side, and oxygen transport in the catalyst layer, respectively.


Author(s):  
John Fagley ◽  
Jason Conley ◽  
David Masten

In recent years, there has been an increasing amount of PEM (proton exchange membrane) fuel cell-related research conducted and subsequently published by universities and public institutions. While a good deal of this research has been useful for understanding the underlying fundamental aspects of fuel cell components and operation, much of it is not as useful for a group working on automotive applications as it could be. The reason for this is that in order to be put to practical use in an automotive application, the system being studied must meet certain constraints; satisfying targets for projected system costs, system efficiency, volumetric and gravimetric power densities (packaging), and operating conditions. For example, numerous recent publications show studies with PEM fuel cells designed and built such that limiting current density is achieved at 0.9 A/cm2 or lower, and voltages of 600 mV can only be achieved at current densities less than 0.6 A/cm2. This type of performance is sufficiently below what is required for commercial application, that any conclusions drawn from these works are difficult to extrapolate to a system of commercial automotive interest. The purpose of this article is to show, through use of engineering calculations and cost projections, what operating conditions and performance are required in a commercial automotive fuel cell application. In addition, best known (public domain) performance and corresponding conditions are given, along with Department of Energy Freedom Car targets, which can be used for state-of-the-art benchmarking. Also, reference is made to a university publication where performance (500 mV at 1.5 A/cm2) close to automotive application targets was achieved, and important aspects of their components and flow field geometry are highlighted. It is our hope that through this publication, further PEM fuel-cell related research can be directed toward the region of greatest interest for commercial, automotive application.


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