• Energy Research
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One of the main problems in electrochemical hydrogen pumps is the transport of protons, water retention and hydrogen crossover through the membrane. Considering prospects for an electrochemical hydrogen compression system, in this work, membranes based on Sulfonated Poly (Ether-Ether Ketone) (SPEEK) were made and modified with Halloysite nanotubes (HNT) and Halloysite nanotubes impreg- nated with phosphotungstic acid (PWA/HNT30)15. These modified membranes were physicochemically characterized by scanning electron microscopy (SEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the nanotubes were suc- cessfully incorporated by impregnating the heteropolyacid on the nanotubes. In addition, the membranes were characterized by swelling (area and volume) and WUp, obtaining a slight decrease in these values. In contrast, the proton conductivity was increased by 42% and 88% for the membranes impregnated with HNTs and (PWA/HNT30)15, respectively. Finally, the membranes were evaluated in a hydrogen pumping system, and lower energy consumption at j = 0.4 A cm-2 has been obtained.

Transportation and portable applications already use hydrogen as fuel, but it is essential to use highly-efficient hydrogen storage methods to increase its usage in the future. The compressed form is the most utilized for transportation applications, but mechanical compressors have low efficiency when compressing low quantities of gas to high pressure. The most suitable device for hydrogen compression is the Electrochemical Hydrogen Compressor (EHC). It has the same structure as a Proton Exchange Membrane Fuel Cell (PEM-FC), but it works at very high-pressure ( 700 bar). The present work analyses the monopolar plate of an Electrochemical Hydrogen Compressor prone to hydrogen embrittlement. Irregular shape variations generate peaks of stress magnitude and triaxiality, further contributing to decreasing metal ductility at the local scale. The calculation of the stress field in such components is essential due to the possibility of failure due to the material embrittlement caused by hydrogen. The paper presents a conceptual design of an EHC operating at 700 bar and focuses on the shape and the mechanical stress of the end-plates to have conservative levels of the nominal stress states, which then are taken as the design parameter for providing adequate structural integrity and mechanical reliability to the component. The FEM analysis with Marc software—of MSC Software Corporation—identified the optimal end-plates configuration in circular plan view and active area. The plate, sized to have a deflection no greater than 0.1mm when the EHC works at 700 bar, should have the minimum thickness of 17 mm.

CNR-ITAE is involved in projects related to hybrid electric fuel cell vehicles, in which different powertrain configurations (from FC full powertrain to range extender) have been evaluated, in terms of the energy flows and system components size. The principal aim is to develop fuel cell-battery hybrid powertrains to be used in vehicles designed for some niche markets. A traction battery pack, a starting battery pack, a fuel cell power module and the combination of a parallel fuel cell-battery hybrid system have been tested. In this latter configuration, the fuel cell is used as main power source for the powertrain, also providing battery charge. The battery has the role to provide peak power during the starts of the vehicle. The hybrid powertrain has shown a fast response even at extreme and impulsive loads and a wider range compared to a battery vehicle, without compromising the weight limitations on the vehicles.