Dynamic characteristics of the local current density in proton exchange membrane fuel cells with different operating conditions

2018 ◽  
Vol 42 (15) ◽  
pp. 4610-4624 ◽  
Author(s):  
Ibrahim Alaefour ◽  
Xianguo Li
Keyword(s):  
Fuel Cells ◽  
Dynamic Characteristics ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Local Current Density ◽  
Local Current ◽  
Exchange Membrane

Effects of Operating Parameters on the Current Density Distribution in Proton Exchange Membrane Fuel Cells

2006 ◽  
Vol 3 (4) ◽  
pp. 464-476 ◽  
Author(s):  
Y. Zhang ◽  
A. Mawardi ◽  
R. Pitchumani
Keyword(s):  
Fuel Cell ◽  
Density Distribution ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Current Density Distribution ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Local Current Density ◽  
Local Current

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.

Current density and polarization curves for radial flow field patterns applied to PEMFCs (Proton Exchange Membrane Fuel Cells)

Energy ◽  
2010 ◽  
Vol 35 (2) ◽  
pp. 920-927 ◽  
Author(s):  
S. Cano-Andrade ◽  
A. Hernandez-Guerrero ◽  
M.R. von Spakovsky ◽  
C.E. Damian-Ascencio ◽  
J.C. Rubio-Arana
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Radial Flow ◽  
Proton Exchange ◽  
Polarization Curves ◽  
Field Patterns ◽  
Exchange Membrane

Design Concepts for Directed Exit Flow in Micro Fuel Cells

2004 ◽  
Author(s):  
Wei Shi ◽  
Sang-Joon Lee
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Design Concepts ◽  
New Concepts ◽  
And Performance ◽  
Electronic Load ◽  
Exchange Membrane

Miniature and micro fuel cells continue to advance as promising alternatives for efficient and portable electric power. This paper presents a study of experimental modifications to the exit flow configuration of microchannels used in small proton-exchange-membrane fuel cells. New concepts for exit geometry are presented, which promote effective water removal and provide reactant back-pressure in an efficient and self-contained manner. Cell assembly is designed such that reactants must necessarily flow laterally through the gas diffusion electrodes near the exit, rather than simply pass over the free backside surfaces of these electrodes. Multiple prototypes were produced using microfabrication techniques with channel sizes of 100 and 200 microns, and performance was tested using a hydrogen-air test station with programmable electronic load. One of the new concepts in particular showed a marked improvement from 28 mW/cm2 peak power density under baseline conditions to 37 mW/cm2 for the modified design under similar operating conditions. The design offers an opportunity for higher performance in miniature fuel cells with low gas consumption and no additional cost.

Design of a Climate Chamber to Study Transient Performance of a Proton Exchange Membrane Fuel Cell at Near Freezing Temperatures

2010 ◽  
Author(s):  
Daniel Cassar ◽  
Xia Wang
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Internal Heat ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Nafion Membrane ◽  
Thermoelectric Device ◽  
Climate Chamber ◽  
Freezing Temperatures ◽  
Exchange Membrane

Freezing temperature startup of fuel cells is a serious issue for smaller applications such as auxiliary or backup power units. To accurately test and examine this problem, a laboratory climate chamber is required which can accurately represent possible environments. This research designed a climate chamber using thermoelectric (peltier) heat pumps to provide temperatures down up to −10 degrees Celsius. The internal heat absorption from air utilized forced convection while heat emitted by the thermoelectric device was removed by flowing water channels. A copper plate was used to provide separation between the heat absorbing plate and the thermoelectric heat pump. The unit showed accurate temperature control and successful operation at sub-zero temperatures. Two proton exchange membrane fuel cells with 117 Nafion membrane and 212 Nafion membrane were tested in the climate chamber under various operating conditions. The startup performance was examined under both freezing and non-freezing temperatures. Heated and humidified feed gasses were shown to greatly improve the steady state time of the 117 setup by over 30%.

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