A MODELING APPROACH TO THE OPTIMIZATION OF LEAD-ACID-BATTERY ELECTRODES

A resistive grid model was used to study the current and ohmic overpot ential distributions along the surface of lead-acid battery electrodes . Analyses were made under two different regimes: the initial behaviou r at high current densities and the response with time at low current densities. At high discharge currents the theoretical results show tha t the geometry of the electrodes and the position of the lug play the most important role in controlling the magnitude of ohmic losses. The best geometry is a square grid with the lug positioned at the upper ce ntre of the electrode. At low discharge currents the model was used to follow the current distribution along the electrode surface as a func tion of time. In this last study the appearance, for long discharge ti mes, of short-circuited concentration microcells localized in certain regions of the electrode surface was noted. The other regions of the e lectrode supply the external discharge current and the excess current necessary to charge the internal microcell.