In
electricity, a
battery is a device consisting of one or more
electrochemical cells that convert stored chemical
energy into electrical energy. Since the invention of the first battery (or "
voltaic pile") in 1800 by
Alessandro Volta and especially since the technically improved
Daniell cell in 1836, batteries have become a common power source for many household and industrial applications. According to a 2005 estimate, the worldwide battery industry generates
US$48
billion in sales each year, with 6% annual growth.
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 to power
hearing aids and wristwatches to battery banks the size of rooms that provide standby power for
telephone exchanges and computer
data centers.