Feasibility of efficiency improvement in a fuel cell system powered by a metal hydride tank

Abstract

Hydrogen has been identified as one of the main axes of the energy transition. Its large-scale development faces several technological barriers. This is the case for the storage method, although today there are generally three methods: high gaseous pressure storage, liquid storage and metal hydride storage. However, only the first two have achieved technological maturity, yet they present several disadvantages in terms of the calorific value used for the compression and liquefaction of hydrogen as well as from the point of view of pressure of use and social acceptance. On the other hand, metal hydride storage offers the technical possibility to operate at low pressure and ambient temperature, with a higher volumetric energy density than the other two methods. Hydrogen storage in metal hydrides is an exothermic process and its release is an endothermic reaction, hence the idea of recovering the waste heat produced by a fuel cell to provide calories to the metal hydride hydrogen reservoir to extract the hydrogen that will in turn feed the fuel cell. This article presents the experimental results of the coupling of a PEMFC fuel cell and a hydrogen metal hydride hydrogen tank. The results obtained highlight the great interest of this solution in terms of improving energy efficiency and safety for stationary and mobile applications.