A millimeter scale reactor integrated PEM fuel cell energy system with an on-board hydrogen production, storage and regulation unit for autonomous small scale applications

Abstract

We present a millimeter scale reactor integrated PEM fuel cell energy source with an on-board hydrogen production reactor (realized by alkaline chemical hydride), and passive hydrogen buffering unit (realized by metal hydride) of hydrogen. A stacked system of reactor-hydrogen buffer -PEM fuel cell is demonstrated. The system is driven by the hydrolysis of the alkaline chemical hydride (NaOH+NaBH₄) in the presence of micro porous catalyst layer (platinum catalyst (Ni-Pt)). The produced hydrogen gas from the reactor is buffered through the hydrogen buffer (Palladium metal hydride) and gets distributed (due to the pressure difference) onto the anode of the PEM fuel cell. The operational behaviour of the complete system is investigated with the hydrogen produced from the alkaline chemical hydride and pure hydrogen gas. Long term voltage measurements under a defined electrical load of the alkaline chemical hydride driven system was measured. The increase in time for the hydrogen production observed in the long term voltage measurement is anticipated to the degradation of the Ni-Pt catalyst. The system is “self-buffering” in nature so any change in electrical load can be handled during system operation.