→ "Battery is a galvanic cell in which chemical energy converted into electrical energy."
→ There are two types of battery.
(1) Primary cell: In the primary batteries, the reaction occurs only once and after use over a period of time battery becomes dead and cannot be reuse again.
e.g. Dry cell, Mercury cell
(2) Secondary cell: A secondary cell after use can be recharged by passing current through it in the opposite direction so that it can be used again.
e.g. lead storage cell, Ni-Cd cell.