Direct Coupling of PEM Fuel Cell to Supercapacitors for Higher Durability and Better Energy Management

Abstract

A single polymer electrolyte fuel cell has been directly hybridized to a stack of three supercapacitors: the system formed has been investigated in operation in the fuel cell dynamic load cycle, which emulates the energy demand in transported applications. Comparison with regular, non‐hybridized fuel cell operation was analyzed in terms of hydrogen consumption in the case that the gas flow rates are directly controlled by cell current during the cycles with constant gas stoichiometric factors: the smoothening effect of the supercapacitors in the overall circuit leads to more even profiles of the cell current and voltage in the cycle, which allows safer and better hydrogen consumption management in this regime: the average H2 consumption per cycle could be reduced by 16% without change of the overall energy produced. Besides, the runs were conducted over more than 1,300 hours with evaluation of the fuel cell performance and capacity at regular intervals, with or without hybridization. A moderate positive effect of hybridization was observed in the time variations of the voltage‐current curves and the fuel crossover. However, the resistances for ohmic, charge transfer and diffusion phenomena, were not so much improved by the hybridization, in spite of less sharp voltage.

Direct hybridization of PEMFC and supercapacitors: Effect of excess hydrogen on a single cell fuel cell durability and its feasibility on fuel cell stack

“…The test bench was controlled by Control-desk software with a dSPACE ® real-time electronic card with Matlab-Simulink ® mathematical environment for all essential control parameters, data acquisition and safety shutdown as used in a previous work [13].…”

“…Interpretation of the spectra obtained by performing EIS technique after every 100 h of fuel cell operation for all the configurations as described in a previous paper [13] was carried out to estimate the ohmic resistance, RΩ, the cathode charge transfer resistance, Rct, and the diffusion resistance of the cathode, Rdc related to the Warburg placed in series with Rct in the cathode circuit.…”

“…7. This voltage increase is partially due to voltammetric investigations, particularly due to the low voltage periods in which slightly oxidized Pt clusters can be reduced back to metal Pt [13].…”

“…Nevertheless, a novel technique suggests connecting directly PEMFC and supercapacitors (SC) in parallel. It has been successful to reduce the hydrogen overfeeding [13]. Moreover, the direct hybridization has shown no detrimental impact on fuel cell core when being tested on driving conditions which represents additional advantage in view to fuel cell systems in transported applications.…”

Evaluation of Graphene Nanoplatelets as a Microporous Layer Material for PEMFC: Performance and Durability Analysis

“…The interest is focused on improving the durability of the cells to satisfy the basic requirements regarding their lifetime, like those expressed by the US Department of Energy that sets the minimum limits at 5,000 h for mobile applications and at 80,000 h for the stationary ones [6][7][8]. This problem is complex and difficult to be faced, because different materials and components are involved in the various processes occurring in the cell, simultaneously each one induces a different degradation mechanism that must be confined while allowing the regular functioning of the device [9,10]. However, it is necessary to assess which phenomena affect the PEMFCs, in order to produce more resistant products that can compete with traditional technologies, such as internal combustion engines.…”