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.
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 prevention remains the best course of action, by periodically fully charging the lead–acid batteries. A typical lead–acid battery contains a mixture with varying concentrations of water and acid.
The formation of this lead sulfate uses sulfate from the sulfuric acid electrolyte surrounding the battery. As a result, the electrolyte becomes less concentrated. Full discharge would result in both electrodes being covered with lead sulfate and water rather than sulfuric acid surrounding the electrodes.
Lead-acid batteries are prone to a phenomenon called sulfation, which occurs when the lead plates in the battery react with the sulfuric acid electrolyte to form lead sulfate (PbSO4). Over time, these lead sulfate crystals can build up on the plates, reducing the battery’s capacity and eventually rendering it unusable.
A lead acid cell is an electrochemical cell, comprising of a lead grid as an anode (negative terminal) and a second lead grid coated with lead oxide, as a cathode (positive terminal), immersed in sulfuric acid. The concentration of sulfuric acid in a fully charged auto battery measures a specific gravity of 1.265 – 1.285.
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…