Regression Analysis of PEM Fuel Cell Transient Response

To develop operating strategies in polymer electrolyte membrane (PEM) fuel cell-powered applications, precise computationally efficient models of the fuel cell stack voltage are required. Models are needed for all operating conditions, including transients. In this work, transient evolutions of voltage, in response to load changes, are modeled with a sum of three exponential decay functions. Amplitude factors are correlated to steady-state operating data (temperature, humidity, average current, resistance, and voltage). The obtained time constants reflect known processes of the membrane heat/water transport. These model parameters can form the basis for the prediction of voltage overshoot/undershoot used in computational-based control systems, used in real-time simulation. Furthermore, the results provide an empirical basis for the estimation of the magnitude of temporary voltage loss to be expected with sudden load changes, as well as a systematic method for the analysis of experimental data. Its applicability is currently limited to thin membranes with low to moderate humidity gases, and with adequately high reactant-gas stoichiometry

High temperature (HT) polymer electrolyte membrande fuel cells (PEMFC) - A review

One possible solution of combating issues posed by climate change is the use of the High Temperature (HT) Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) in some applications. The typical HT-PEMFC operating temperatures are in the range of 100e200 o C which allows for co-generation of heat and power, high tolerance to fuel impurities and simpler system design. This paper reviews the current literature concerning the HT-PEMFC, ranging from cell materials to stack and stack testing. Only acid doped PBI membranes meet the US DOE (Department of Energy) targets for high temperature membranes operating under no humidification on both anode and cathode sides (barring the durability). This eliminates the stringent requirement for humidity however, they have many potential drawbacks including increased degradation, leaching of acid and incompatibility with current state-of-the-art fuel cell materials. In this type of fuel cell, the choice of membrane material determines the other fuel cell component material composition, for example when using an acid doped system, the flow field plate material must be carefully selected to take into account the advanced degradation. Novel research is required in all aspects of the fuel cell components in order to ensure that they meet stringent durability requirements for mobile applications.Web of Scienc

Monodimensional modeling and experimental study of the dynamic behavior of proton exchange membrane fuel cell stack operating in dead-end mode

International audienceThe dynamic behavior of a five cells proton exchange membrane fuel cell (PEMFC) stack operating in dead-end mode has been studied at room temperature, both experimentally and by simulation. Its performances in “fresh” and “aged” state have been compared. The cells exhibited two different response times: the first one at about 40 ms, corresponding to the time needed to charge the double-layer capacitance, and the second one at about 15–20 s. The first time response was not affected by the ageing process, despite the decrease of the performances, while the second one was. Our simulations indicated that a high amount of liquid water was present in the stack, even in “fresh” state. This liquid water is at the origin of the performances decrease with ageing, due to its effect on decreasing the actual GDL porosity that in turn cause the starving of the active layer with oxygen. As a consequence, it appears that water management issue in a fuel cell operating in dead-end mode at room temperature mainly consists in avoiding pore flooding instead of providing enough water to maintain membrane conductivity

Long Term Testing in Dynamic Mode of HT-PEMFC H3PO4/PBI Celtec-P Based Membrane Electrode Assemblies for micro-CHP Applications

International audienc

Experimental methods for the diagnosis of PEMFC stacks, Workshop

International audienc

Experimental methods for the diagnosis of PEMFC stacks, Workshop

International audienc

Signal-Based Diagnostics by Wavelet Transform for Proton Exchange Membrane Fuel Cell

AbstractIn order to exploit all the benefits from the Proton Exchange Membrane Fuel Cell (PEMFC) technology and to gain a deeper understanding of operating faults during fuel cell operations, Investigation of the origins of faults is necessary.In this work, a diagnosis approach consisting of a method using signal-based pattern recognition is proposed. It is aimed at a minimization of efforts and costs in acquisition and evaluation of data for diagnostic purposes. All information needed to locate the faults is drawn from the recorded fuel cell output voltage, since certain phenomena leave characteristic patterns in the voltage signal. A signal analysis tool, namely the Wavelet Transform (WT), is employed to identify different patterns or faults signatures.The approach has been applied to voltage data recorded on a PEMFC suffering from dysfunctions related to inappropriate humidity levels inside the cell (two different faults are simulated: flooding and drying out). Characteristic features in the output voltage signals were outlined, so a distinction of several states of health was accomplished.The results show the efficiency of the proposed approach, and the WT can be considered as a reliable method to localize the dysfunctions. A comparison between the Discrete Wavelet Transform (DWT) and the Continuous Wavelet Transform (DWT) has shown that the DWT is more efficient in detecting and localizing faults in fuel cells