Special Issue: Modern Sensing Technologies

Vol. 90, April 2008, pp. 150-159

Signal Processing for the Impedance Measurement on an Electrochemical Generator

El-Hassane AGLZIM, Amar ROUANE, Mustapha NADI
and Djilali KOURTICHE

LIEN, Nancy Université, Boulevard des Aiguillettes, BP239 54506 Vandoeuvre lès Nancy - France

E-mail: el-hassane.aglzim@lien.uhp-nancy.fr

 Received: 15 October 2007   /Accepted: 20 February 2008   /Published: 15 April 2008

Abstract: Improving the life time of batteries or fuel cells requires the optimization of components such as membranes and electrodes and enhancement of the flow of gases [1], [2]. These goals could be reached by using a real time measurement on loaded generator. The impedance spectroscopy is a new way that was recently investigated. In this paper, we present an electronic measurement instrumentation developed in our laboratory to measure and plot the impedance of a loaded electrochemical generator like batteries and fuel cells. Impedance measures were done according to variations of the frequency in a larger band than what is usually used.

The electronic instrumentation is controlled by Hpvee^® software which allows us to plot the Nyquist graph of the electrochemical generator impedance. The theoretical results obtained in simulation under Pspice^® confirm the choice of the method and its advantage. For safety reasons, the experimental preliminary tests were done on a 12 V vehicle battery, having an input current of 330 A and a capacity of 40 Ah and are now extended to a fuel cell.

The results were plotted at various nominal voltages of the battery (12.7 V, 10 V, 8 V and 5 V) and with two imposed currents (0.6 A and 4 A). The Nyquist diagram resulting from the experimental data enable us to show an influence of the load of the battery on its internal impedance. The similitude in the graph form and in order of magnitude of the values obtained (both theoretical and practical) enables us to validate our electronic measurement instrumentation. Different sensors (temperature, pressure) were placed around the device under test (DUT). These influence parameters were permanently recorded. Results presented here concern a classic loaded 12 V vehicle battery.

The Nyquist diagram resulting from the experimental data confirms the influence of the load of the DUT on its internal impedance.

Keywords: Fuel cell on load, Impedance Spectroscopy method, Impedance measurement, Nyquist graph.

Click <here> or title of paper to download the full pages article (1.85 Mb)

1999 - 2008 Copyright ©, International Frequency Sensor Association (IFSA). All Rights Reserved.

Home - News - Links - Archives - Tools - Standardization - Patents - Marketplace - Projects - Wish List - Subscribe - Search - e-Shop - Membership

 Members Area -Sensors Portal -Training Courses - S&T Digest - For advertisers - Bookstore - Forums - Polls - Sensor Jobs - Site Map