Characterization of 1-5 Stack Fuel Cells with Electrochemical Impedance Spectroscopy

Fuel cells (FC) have an important role in an alternative energy. They produce lower quantities of greenhouse gases. A Proton-Exchange-Membrane (PEM) FC is an electrochemical device where a fuel, H2, reacts with O2 producing electricity and water. A characterization of this process gets a competent and reliable evaluation of this energy source. Therefore, Electrochemical Impedance Spectroscopy (EIS) is used to study the performance of the FC. It consists of modeling the FC as an electric circuit and measuring its response utilizing Nyquist and Bode Plots, impedance techniques. This involves applying a small sinusoidal voltage wave to the cell at different cell potentials and at several frequencies.

In practice FC consist of a stack that includes several cells. Stacks, however, are less characterized due in part to their lack of availability. This project consists of comparing the performance of a single to 5 stacks FC. Preliminary studies with a 3 stack cell indicate that EIS is still effective to characterize inherent inefficiencies of the cells such as activation polarization and ohmic losses even in a stack. Ongoing experiments are intended to continue studying and comparing the performance of a FC to obtain a more comprehensive understanding of the system.