Rechargeable batteries are recharged by passing currents of electricity through them.
Rechargeable batteries, also known as secondary cells, are designed with reversible chemical reactions. This reversibility allows them to regain their cell potential, or recharge, when an electric current is passed through them in the opposite direction of discharge. This process essentially reverses the chemical reactions that occur during discharge, restoring the battery to its charged state.
In summary, the process involves forcing electrons back into the battery using an external power source, reversing the electrochemical reactions that depleted the battery's charge. This replenishes the chemical compounds within the battery that are responsible for generating electricity.
