Impact of humidification by cathode exhaust gases recirculation on a PEMFC system for automotive applications

International audienceReactant gases humidification, in most PEM fuel cell systems, is traditionally implementedto ensure both stack durability and superior performance. A cathode exhaust gases recirculationarchitecture allows to decrease the system volume compared to the passive humidifiers,which are classically used. Incorrect water management being responsible forirreversible degradations, a control of relative humidity at stack inlet thanks to the recirculationcould be of great interest to limit their impact. In this work, investigations onperformance and stability are performed during operation in recirculation mode, from thecell scale to the system scale. It was observed that high to medium recirculation ratios wereable to stabilize and homogenize the cells voltages along the stack but performance wasreduced due to oxygen dilution by nitrogen. Besides, large relative humidity ranges wereachieved at stack inlet, which can vary from 25 to 85% and could be able to follow automotivedynamics

Simplified anode architecture for PEMFC systems based on alternative fuel feeding: Experimental characterization and optimization for automotive applications

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Determination of current density distribution in proton exchange membrane fuel cells

This study is to look at the distribution of current densities in proton exchange membrane fuel cells (PEMFC) to enable optimisation of fuel cell performance. The feasibility of using a new measurement technique of the local magnetic field, in the conductive plates of the cell was studied. The magnetic field is measured throughout the cell using the Maxwell equations and the current densities calculated. The measurement system and its validation are outlined in the first section. The next section outlines the experimental current density distribution within the cell, operating under standard conditions and special configurations, such as the partially active membrane electrodes assembly (MEA). Using a Matlab or Femlab model of the cell, (which is briefly outlined) our experiments are compared and an attempt made to explain the distribution of the current densities. Finally recent developments of the device are described, which will be used in several tests of PEMFC small stacks

Investigation of liquid water heterogeneities in large area PEM fuel cells using a pseudo-3D multiphysics model

International audienceEffective management of the liquid water and heat produced in Proton Exchange Membrane Fuel Cell(PEMFC) is necessary to increase both its performance and durability. In previous works, a pseudo-3Dphysic-based model of heat and water transport in fuel cells was developed and has been validatedagainst experimental temperature and current density data. In this study, liquid water measurementobtained from neutron imaging tests is compared with numerical results. The model is able to predictqualitatively the presence of liquid water with a good accuracy taking into account the real BipolarPlate (BP) design. Based on the reliability of the predictions at this first order in-plane space scale, themodel has been used to compute the thickness of liquid water through the plane of the cell, in the differentcomponents of the stack, Gas Channel (GC) or Gas Diffusion Electrode (GDE). Our two-phase flowformulation has also been compared to more classical phase-separated two-phase flow model. A goodaccordance is observed for low saturations. The good agreement between predictions and measurementresults supports the capability of our model to be employed in predictive control strategies or to designinnovative Bipolar Plate (BP) at lower cost compared to experimental tests