scholarly journals On the distribution of local current density along a PEM fuel cell cathode channel

2019 ◽  
Vol 101 ◽  
pp. 35-38 ◽  
Author(s):  
Tatyana Reshetenko ◽  
Andrei Kulikovsky
2006 ◽  
Vol 3 (4) ◽  
pp. 464-476 ◽  
Author(s):  
Y. Zhang ◽  
A. Mawardi ◽  
R. Pitchumani

During the operation of a proton exchange membrane (PEM) fuel cell, significant variation of the local current density could exist across the cell causing sharp temperature and stress gradients in certain points, and affecting the water management, all of which severely impact the cell performance and reliability. The variation of local current density is a critical issue in the performance of PEM fuel cell, and is influenced by the operating conditions. This article presents a model-assisted parametric design with the objective of determining the operating conditions which maximize the fuel cell performance while maintaining a level of uniformity in the current density distribution. A comprehensive two-dimensional model is adopted to simulate the species transport and electrochemical phenomena in a PEM fuel cell. Numerical simulations are performed for over a wide range of operating conditions to analyze the effects of various operating parameters on the variation of local current density of the fuel cell, and to develop design windows which serve as guideline in the design for maximum power density, minimum reactant stoichiometry, and uniform current density distribution.


Author(s):  
Shan Jia ◽  
Hongtan Liu

In a PEM fuel cell, local current density can vary drastically under the land and channel areas. The non-uniform current density distribution not only affects the overall performance of the fuel cell, but also leads to the local temperature and concentration differentiation on the MEA, which can cause problems such as membrane dehydration and catalyst degradations at certain locations. In order to investigate the local current performance, the objective of this work is to directly measure the local current density variations across the land and channel at the cathode in a PEM fuel cell with partially-catalyzed MEAs. First, the cathode flow plate is specially designed with a single-serpentine channel structure, and the gas diffusion electrode at cathode side is cut to fit this flow field size (5.0cm×1.3cm). Then five different partially-catalyzed MEAs with 1mm width corresponding to different locations from the middle of the gas channel to the middle of the land area are made. Fuel cells with each of the partially-catalyzed MEAs have been tested and the results provide the lateral current density distribution across the channel and the land areas. In the high cell voltage region, local current density is highest under the center of the land area and decreases toward the center of the channel area; while in the low cell voltage region local current density is highest under the middle of the channel area and decrease toward the center of the land area. Different flow rates are tested at the cathode side of the cell to study their effects on the local current density performance along the land-channel direction. And the results show that the flow rate barely has the effect on the current at the high cell voltage region, while it plays a significant role at the low voltage region due to the mass transport effect.


2010 ◽  
Vol 195 (24) ◽  
pp. 8089-8093 ◽  
Author(s):  
Hui Li ◽  
Ken Tsay ◽  
Haijiang Wang ◽  
Jun Shen ◽  
Shaohong Wu ◽  
...  

Author(s):  
Shaoping Li ◽  
Jing Cao ◽  
William Wangard ◽  
Ulrich Becker

A 3-dimensional, two-phase Computational Fluid Dynamics (CFD) model for PEMFC simulations has been developed and implemented in FLUENT, a general-purpose commercial software package with multi-physics capabilities. The model formulation was given in details in the previous ASME fuel cell conference, together with in-situ distributions of current densities and species concentrations computed for a simple geometry. In this paper, numerical performance of this model in terms of computing time and parallel efficiency are assessed through the computation of a relatively larger-size fuel cell (50 cm2) with serpentine channels. The convergence history and parallel performance data show that the Fluent’s PEMFC model is numerically robust and efficient. In addition to the numerical performance, the physical validity of the model is tested through comparisons with experimental data of polarization curves and local current density distributions from the most recent work of Mench et al [1]. Comparisons with the data show good agreement in the overall polarization curves and reasonably good agreement in local current density distributions too. The comma-shaped local polarization curves seen in the experiments are qualitatively correctly captured. Moreover, our computations show that hydrogen mass fraction and molar concentration can both increase along the anode flow channel, despite that hydrogen is being depleted in the anodic electrochemical reaction. The reason for this to happen is that the osmotic drag moves the water from anode to cathode at a much faster rate than the hydrogen depletion rate. An analytical derivation that reveals the relationship between species molar concentration and mass fraction is also given.


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