Voltage of lead acid battery upon charging. The charging reaction converts the lead sulfate at the negative electrode to lead. At the positive terminal the reaction converts the lead to lead oxide. As a by-product of this reaction, hydrogen is evolved.
Such applications include automotive starting lighting and ignition (SLI) and battery-powered uninterruptable power supplies (UPS). Lead acid battery cell consists of spongy lead as the negative active material, lead dioxide as the positive active material, immersed in diluted sulfuric acid electrolyte, with lead as the current collector:
Battery Application & Technology All lead-acid batteries operate on the same fundamental reactions. As the battery discharges, the active materials in the electrodes (lead dioxide in the positive electrode and sponge lead in the negative electrode) react with sulfuric acid in the electrolyte to form lead sulfate and water.
The discharge state is more stable for lead–acid batteries because lead, on the negative electrode, and lead dioxide on the positive are unstable in sulfuric acid. Therefore, the chemical (not electrochemical) decomposition of lead and lead dioxide in sulfuric acid will proceed even without a load between the electrodes.
Electrode potentials and cell voltage for a typical flooded lead–acid battery As charging proceeds, the potentials keep gradually increasing until end of charge is reached. At this point, all lead sulfate is converted to lead on the negative electrode and to lead dioxide on the positive; and the charge is complete.
Wide differences in cycle performance may be experienced with two types of deep cycle batteries and therefore the cycle life and DOD of various deep-cycle batteries should be compared. A lead acid battery consists of electrodes of lead oxide and lead are immersed in a solution of weak sulfuric acid.
When the battery is recharged, a current (conventional direction) is made to flow into the positive electrode of each cell. This current causes the lead sulfate at the negative electrode to recombine with hydrogen ions, thus re-forming sulfuric …