A lead acid battery consists of a negative electrode made of spongy or porous lead. The lead is porous to facilitate the formation and dissolution of lead. The positive electrode consists of lead oxide. Both electrodes are immersed in a electrolytic solution of sulfuric acid and water.
Following are some of the important applications of lead – acid batteries : As standby units in the distribution network. In the Uninterrupted Power Supplies (UPS). In the telephone system. In the railway signaling. In the battery operated vehicles. In the automobiles for starting and lighting.
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.
Sulfation , which means the formation of PbSO 4, is another serious problem with lead–acid batteries. Normally, as the lead–acid batteries discharge, lead sulfate crystals are formed on the plates.
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.
Another important performance factor for lead–acid batteries is self-discharge, a gradual reduction in the state of charge of a battery during storage or standby. The self-discharge takes place because of the tendency of battery reactions to proceed toward the discharged state, in the direction of exothermic change or toward the equilibrium.
OverviewHistoryElectrochemistryMeasuring the charge levelVoltages for common usageConstructionApplicationsCycles
The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté. It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have relatively low energy density. Despite this, they are able to supply high surge currents. These features, along with their low cost, make them attractive for u…