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One of the most outstanding products of fuel cells is electrical power but, currently, there is a reduced number of publications that provide experimental data about the performance of fuel cells when used for supplying Alternating Current (AC) loads. Most of the existing publications provide experimental data only with direct current (DC) loads, or analyze the performance with AC loads using simulation models. For this reason, this paper analyses experimentally the behavior of a proton exchange membrane fuel cell (PEMFC) system when feeding different electrical loads. The system tested is constituted by a PEM fuel cell, a storage battery, electronic converters and electrical loads. In the tests, the fuel cell system supplies power to three different loads: DC, single‐phase AC and three‐phase AC. For these cases, voltage, current, power, power factor and efficiency data are shown, at different load levels. From those parameters, efficiency of the global system is estimated. Finally, as the power quality concept is a topic of increasing importance when supplying electricity, the total harmonic distortion (THD) of the electric signals has also been analyzed.

This paper is devoted to the modeling of a PEMFC fuel cell stack. First, to justify the hypotheses, original experimental results are presented and show that the gas flow rates feeding a cell in its stack environment highly depend on the thermal management. Then, the generic model of a cell in its stack environment is presented. A two-phase flow model is implemented to calculate the gas flow rates as a function of the pressure drops and considering the amount of liquid water present in both compartments. In this way, the dispatching of the total active gases flow rate between the different cells can therefore be described. Finally, a stack of five cells is numerically assembled by describing the thermal coupling between the cells. Two application examples are conducted. A first one considers a cooling defect and a second one simulates the case where one cell is more degraded than the others. It is shown how these types of malfunction can cause a fuel starvation event. At the end, and for the first time as far as we know, a mechanism of propagation of degradations from cell to cell is proposed. List of symbols SymbolDescriptionUnitSymbolDescriptionUnit Double-layer capacity of the cellF Protonic resistance of the membrane and electrodesΩ water vapor concentrationmol m−3 Thermal resistanceK W−1 Oxygen Concentrationmol m−3 Mass transfer reisstances m−3 Concentration of the saturated vapor at T mol m−3 Water saturation in the channels Specific heat capacity of plateJ/K.kg TemperatureK Effective water vapor diffusion coefficient through the GDLm2 s−1 Cell potentialV Water diffusion coefficient in the membranem2 s−1 Volume of channels m3 Effective oxygen diffusion coefficient through the GDLm2 s−1 Greek Letters Thickness of the GDLm Anodic charge transfer coefficient Standard cell potentialV Cathodic charge transfer coefficient Equivalent weight of the membranekg mol−1 Roughness factor of the electrode Faraday constantC mol−1 Pressure dropPa Current intensityA Electro-osmosis coefficient Exchange current densityA m−2 Water content of the membrane thermal capacity of the MEAJ K−1 Effective thermal conductivity of GDLW mK−1 thermal capacity of the anode/cathode platesJ K−1 Volumetric masskg m−3 Length of the active aream Cathode electrode potentialV Water latent heatkJ mol−1 Upper & lower scripts lower heating value of HydrogenkJ mol−1 in Inlet Molar mass of waterkg mol−1 out Outlet Dry air molar flow ratemol s−1 c Cathode Dry hydrogen molar flow ratemol s−1 a Anode Water vapor molar flow ratemol s−1 ch Channels Water vapor flow rate from electrode to channelsmol s−1 el Electrode Atmospheric pressuremol s−1 m Membrane Total pressure in the anode channelsPa cf Cooling fluid Total pressure in the cathode channelsPa n−1Preceding electrode Universal gas constantJ mol.K−1 n + 1Following electrode Electrical resistance of the cellΩ

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This paper proposes a model to study the degradation of li-ion NMC batteries of commercial electric vehicles. The model takes into account operation variables such as operating CRate , Depth of Discharge (DoD), Number of Cycles and Temperature using a 4-D Piecewise Cubic Hermite Interpolating Polynomial (PCHIP). Simulations have been done considering the Worldwide Harmonised Light Vehicles Test Procedure 3 (WLTP3) standard cycle. The model has been implemented in MATLAB. In addition, recommendations on charging procedures are given in order to reduce the degradation of batteries.