A Lowpass Pulsed Excitation and Method for Polarization Resistance Measurements

Abstract

A new method to measure the polarization resistance on electrochemical cells is proposed. The method is based on the application of a new pulsed excitation, which exhibits low pass frequency contents, and time domain analysis. In other pulsed excitation methods, curve fitting algorithms are used to find values for equivalent RC models. In our approach using this pulsed excitation, single values of potential and current measurements, at a very precise time, are needed to obtain the value of the polarization resistance. A numerical simulation was first developed and then, the method was tested using equivalent analog circuits and electrochemical cells. The pulsed excitation method was also compared with electrochemical impedance measurements, where the modulus of the impedance, at the minimum testing frequency, was taken as an estimation of the polarization resistance. According to the experimental results, the proposed method can be used in new instrumentation designs, where the main goal is to obtain a value of the polarization resistance.