Effect of cathode design on the performance of an air-breathing fuel cell is studied using a three dimensional, non-isothermal, steady state and single phase model developed using commercial CFD software FLUENT (version 6.3). Performances of ducted (channel) and ribbed (planar) cathode designs are compared and the cell characteristics such as current density, species, temperature distributions, velocity and net water transport coefficient are presented. Peak power density obtained for the cell with ducted cathode is 205 m W/cm2, whereas with ribbed cathode it is 232 m W/cm2. The limiting current density of the cell with ribbed cathode (690 m A/cm2) is much higher than that of the cell with ducted cathode (430 m A/cm2). The performance curves as well as the cell characteristics show that the ribbed cathode design is a better configuration compared to ducted design. Cell orientation has a significant effect on the cell performance. Best performance is obtained when the cell is oriented vertically for both ribbed and ducted cathode designs. © 2009 Professor T. Nejat Veziroglu.

Ajit Kumar Kolar

AIR BREATHING

CATHODE DESIGN

Cell orientation

Cell performance

CFD SOFTWARES

EFFECT OF CATHODE

LIMITING CURRENT DENSITY

Nonisothermal

PEAK POWER DENSITIES

PEM fuel cell

PERFORMANCE CURVE

SINGLE-PHASE MODEL

steady state

Water transport

Cells

Design

Proton exchange membrane fuel cells (PEMFC)

three dimensional

Cytology

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

International Journal of Hydrogen Energy

This paper presents a two-dimensional, steady state, single phase, non-isothermal and complete model for a vertical, fully planar, Air Breathing Proton Exchange Membrane Fuel Cell (AB-PEMFC) with hydrogen fuel supplied by forced convection at the anode. It is applied to a cell with an active area of 6 cm2 operating at ambient atmospheric conditions of 23 °C and 20% relative humidity. The transport characteristics in terms of the velocity, and heat and mass transfer coefficients in the various components of the fuel cell are reported for several values of the operating current density. The effect of cathode height (1-5 cm) and operating atmospheric conditions (10-40 °C and 20-80% relative humidity), on the cell performance is also reported. Further, the applicability of the model to a non-planar AB-PEMFC is examined by comparison with available experimental data. The average mass transfer coefficients for oxygen and water vapor at the cathode GDL surface are found to be of the order of 10-3 m s-1. The operating current density is seen to substantially affect the variation of the local current density distribution and the cathode surface temperature along the height of the fuel cell as also the temperature variation across the MEA thickness. The maximum power density and the corresponding current density, herein defined as the optimum current density, are found to increase with decreasing height of the fuel cell, decreasing ambient temperature and increasing ambient relative humidity. However, the local cell temperature at high current densities is found to increase beyond the safe operating limits for short fuel cells. Comparison of the model predictions with available experimental data points to its applicability in the ohmic polarization zone of a non-planar cell. The cell performance at high current densities deteriorates due to mass transport limitation and electrolyte dehydration. © 2006.

Journal of Power Sources

A model for a vertical planar air breathing PEM fuel cell

Convection Heat Transfer

International Journal of Heat and Mass Transfer

Numerical studies on an air-breathing proton exchange membrane (PEM) fuel cell

Numerical studies on an air-breathing proton exchange membrane (PEM) fuel cell stack

Concentration and ohmic losses in free-breathing PEMFC

Effect of cathode design on the performance of an air-breathing PEM fuel cell

Journal	International Journal of Hydrogen Energy
ISSN	03603199
Open Access	No