Battery

Main article: Battery (electricity)

Alkaline batteries

A battery is a device that converts stored chemical energy to electrical energy. Batteries are commonly used as energy sources in many household and industrial applications.
There are two types of batteries: primary batteries (disposable batteries), which are designed to be used once and discarded, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times. Batteries come in many sizes, from miniature cells used in hearing aids and wristwatches to room-size battery banks that serve as backup power supplies in telephone exchanges and computer data centers.