Current and Potential Distributions of Large-Sized Positive Plate in Its Formation of Lead-Acid Batteries

The current and potential distributions on the large-sized flat positive plate of lead-acid batteries in its formation have been studied by an in situ electrochemical scan technique. The formation can be divided into three stages. The first is before 15% charge amount. At this stage, the conductivity of the positive paste is dominant. At the second stage, from about 15 to 62% charge, the formation rate depends on both the electrochemical reactions and ohmic polarization. At the final stage, the electrochemical reactions are a rate-limiting step. At the beginning of the formation, the distributions of the potential, current and polarization resistance are uneven, depending on the evolution of the conductive zones. In comparison with the tubular positive plate, the distributions of potential and current are more uniform in the formation of the flat positive plate and the polarization is much smaller. The violent oxygen bubble evolution at the beginning will result in high contact resistance of local active mass. © 2005 The Electrochemical Society. All rights reserved.