The lead storage battery is used in automobiles. It is a secondary battery and is a reversible cell which can be restored to its original condition. The battery can be used through repeated cycles of discharging and recharging.
The figure shows a portion of the cell in the lead storage battery. There are several anodes and several cathodes which are connected together in series; ab·out six cells are connected together.
Each cell has a voltage of 2V and overall voltage when six cells are connected together in series would be 12V.
In lead storage battery anodes are the lead alloy and cathodes are made up of red lead dioxide (Pb02). The electrolyte is dilute sulphuric acid. Which has a concentration of 30%?
As the cell reaction proceeds PbS04(s) precipitates and partially coats both the electrodes, the water formed dilutes the sulphuric acid. The battery is said to be discharged. Now by connecting the battery to an external electrical source, we can force the electrons to flow in the opposite direction, i.e. the net cell reaction can be reversed and the battery is recharged.