<div class="section abstract"><div class="htmlview paragraph">This paper presents a Fuel Cell Electric Vehicle (FCEV) powertrain development and optimization, aiming to minimize hydrogen consumption. The vehicle is a prototype that run at the Shell Eco-marathon race and its powertrain is composed by a PEM fuel cell, supercapacitors and a DC electric motor. The supercapacitors serve as an energy buffer to satisfy the load peaks requested by the electric motor, allowing a smoother (and closer to a stationary application) working condition for the fuel cell. Thus, the fuel cell can achieve higher efficiency rates and the fuel consumption is minimized.</div><div class="htmlview paragraph">Several models of the powertrain were developed using MATLAB-Simulink and then experimentally validated in laboratory and on the track. The proposed models allow to evaluate two main arrangements between fuel cell and supercapacitors: 1) through a DC/DC converter that sets the FC current to a desired value; 2) using a direct parallel connection between fuel cell and supercapacitors.</div><div class="htmlview paragraph">The results obtained with the direct parallel connection (with the appropriate sizing of the overall capacity) have highlighted a significant efficiency advantage, while the DC/DC converter insertion enables an improved control of the fuel cell current and requires a smaller capacitance.</div><div class="htmlview paragraph">Furthermore, a sizing methodology for the supercapacitors capacitance is proposed for both layouts: with the DC/DC converter it mainly depends on the energy range provided by supercapacitors to the electric motor, while in the direct parallel connection the supercapacitors sizing is outlined by concurrently evaluating the circuit’s predicted hydrogen consumption and granting the most suitable conditions to increase the fuel cell performance.</div><div class="htmlview paragraph">Finally, the results obtained from the model were validated by comparing them with experimental data obtained in the laboratory and on the track.</div></div>

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Humidity and temperature have an essential influence on PEM fuel cell system performance. The water content within the polymeric membrane is important for enhancing proton conduction and achieving high efficiency of the system. The combination of non-stationary operation requests and the variability of environment conditions poses an important challenge to maintaining optimal membrane hydration. This paper presents a humidification and thermal control system, to prevent the membrane from drying. The main characteristics of such a device are small size and weight, compactness and robustness, easy implementation on commercial fuel cell, and low power consumption. In particular, the NTHS method was studied in a theoretical approach, tested and optimized in a laboratory and finally applied to a PEMFC of 1 kW that supplied energy for the prototype vehicle IDRA at the Shell Eco-Marathon competition. Using a specific electronic board, which controls several variables and decides the optimal reaction air flow rate, the NTHS was managed. Furthermore, the effects of membrane drying and electrode flooding were presented.