noun

A device consisting of one or more cells, in which chemical energy is converted into electrical energy by means of a chemical reaction, used as a power source for portable electronic devices, such as laptops and smartphones, as well as for vehicles and backup power supplies.

Example

1. My phone died because the battery was low.
2. I need to buy a new battery for my car.
3. I always carry a spare battery for my camera in case the original one runs out of power.