Relaxation Processes in Fuel Cells

Abstract

The purpose of this research is study of relaxation processes of Proton Exchange Membrane Fuel Cell (PEMFC) potential caused by changing producing electrical current. For transient analysis, it is used a simple model that includes one exponent, and described by three parameters: voltage after transient process (UL), amplitude of the exponent (U1), and time constant (α). Analysis of the experimental results shows that the most highly variable parameter of the relaxation processes during the long-time operation of the FC is U1, while the most stable is UL. Monotonic variation of these parameters in time allows to make an assumption about the possibility of using them for describing, studying and predicting the aging processes of fuel cells. It is also shown that the most rapid variation of these parameters is observed at high load current field, which corresponds to the fastest aging processes.