Effect of supercapacitors directly hybridized with PEMFC on the component contribution and the performance of the system

Hybridization of a fuel cell (FC) with energy storage systems such as supercapacitors (SC) or batteries can make the fuel cell withstand the sudden fluctuations of the current. Moreover, direct hybridization of a FC with SCs (i.e. without power converters) has further proved out to be a better solution than the indirect mode (i.e. with power converters), in addition without inducing further ageing of the cell in non-steady operations. The present investigation was aimed at comparing the performance of the system in terms of yield and the component contributions of the fuel cell and the supercapacitor in power conversion on increasing the capacity of energy storage. A single 100 cm(2) cell was directly hybridized to one or three 3000 F SCs in standard fuel cell dynamic load cycling operation, simulating the energy demand in urban transport with current varying in the range 0-100 A. Upon comparing the hydrogen supply for the two configurations (1 or 3 SC), increasing the SC number decreased the hydrogen amount required in a cycle by approximately 5%. This also enhanced the yield of the fuel cell and the hybrid source by 10 and 16% respectively. Moreover, increasing the SCs capacity reduces the power supplied by the FC in periods with high energy demand in cycling tests. [GRAPHICS] .