Internal resistance and deterioration of VRLA battery-analysis of internal resistance obtained by direct current measurement and its application to VRLA battery monitoring technique

Abstract

In this report, attention is placed on the ohmic resistance, not on the conventional AC impedance of the valve-regulated Pb-acid (VRLA) battery. Based on the various effects obtained in the course of analyzing resistance, it has been confirmed that the internal resistance of a deteriorated battery increases as the resistance of positive plates increases. In addition, a means for identifying another deterioration mode (dry-out) applied using ohmic resistance is described. At the same time, the authors' concept for estimating the remaining life of VRLA batteries is proposed.