CURRENT DISTRIBUTION IN POROUS LEAD DIOXIDE ELECTRODE

A theoretical analysis of initial current distribution in the porous lead dioxide electrode is made by application of the macrohomogeneous model for porous electrodes. The parameters in the model have been determined experimentally for the investigated lead-dioxide battery plates. The theoretical results are in good agreement with experimental determinations by means of electron microprobe analysis of the PbSO//4-distribution within partly discharged positive lead-acid plates. The experimental studies of current distribution shows that at high current densities the electrode reaction takes place mainly in the outer layers of the eelectrode. At low discharge currents, the initial current distribution is uniform while after the first quarter of discharge, the outer layers are more utilized than the inner parts. A mechanism for the passivation of the positive plate in the lead-acid battery is proposed.