ON THE RESISTANCE OF THE GRID ACTIVE MATERIAL INTERPHASE IN LEAD-ACID-BATTERY ELECTRODES

The contact resistance between the active PbO2 mass and a lead grid was measured in situ by a dc method. The influence of the rib resistance was analysed mathematically and the corresponding correction was determined. The slow decrease of the contact resistance of a thermopassivated electrode with the time is discussed in terms of solid-state diffusion of sulphate ions. The lead grid/active mass interface is insensitive against discharge up to 60% of the capacity, whereas at deeper discharges its resistance increases in accord with Winsel's "aggregate of spheres" model. The dependence of the contact resistance on the concentration of H2SO4 is essentially in accord with Garche's studies of the passivating layer on lead.