Hydrogen-powered vehicles are emerging as a key source for a clean and sustainable mobility scenario. In particular, hydrogen technologies have a great potential for light mobility in urban areas, where traffic congestion may cause very high levels of local pollution. In this context, hybrid fuel cell/battery vehicles represent a promising solution, since they allow for extended driving range and short recharge time, which are two of the major concerns related to electric propulsion, in general. In this work, a new plug-in fuel cell electric bicycle concept is presented, where the on-board energy storage is realized by means of an innovative system integrating a battery pack with a metal hydride hydrogen tank. This solution allows to achieve very high performance in terms of riding range, which are unattainable with traditional battery electric bicycles. In particular, the hybrid energy storage system is conceived to provide an optimal thermal management of the two integrated components. The proposed design is developed on the basis of typical duty cycles acquired during on-road measurements. A prototype of the bicycle is then realized and bench-tested in order to assess design consistency and to evaluate its performances. The results show that the riding range of the new hydrogen-fuelled bicycle is about three times higher than the one for a similar electric bicycle.

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The thermal management of lithium-ion batteries in hybrid electric vehicles is a key issue, since operating temperatures can greatly affect their performance and life. A hybrid energy storage system, composed by the integration of a battery pack with a metal hydride-based hydrogen storage system, might be a promising solution, since it allows to efficiently exploit the endothermic desorption process of hydrogen in metal hydrides to perform the thermal management of the battery pack. In this work, starting from a battery electric scooter, a new fuel cell/battery hybrid powertrain is designed, based on the simulation results of a vehicle dynamic model that evaluates power and energy requirements on a standard driving cycle. Thus, the design of an original hybrid energy storage system for a plug-in fuel cell electric scooter is proposed, and its prototype development is presented. To this aim, the battery pack thermal power profile is retrieved from vehicle simulation, and the integrated metal hydride tank is sized in such a way to ensure a suitable thermal management. The conceived storage solution replaces the conventional battery pack of the vehicle. This leads to a significant enhancement of the on-board gravimetric and volumetric energy densities, with clear advantages on the achievable driving range. The working principle of the novel storage system and its integration within the powertrain of the vehicle are also discussed.