"In electronics, a battery or voltaic cell is a combination of one or more electrochemical Galvanic cells which store chemical energy. These cells create a voltage difference between the terminals of the battery. When an external electrical circuit is connected to the battery, then the battery drives an electric current through the circuit and electrical work is done."
One of the most remarkable and novel discoveries in the last 400 years was electricity.
In 1786, Luigi Galvani notices the reaction of frog legs to voltage. He used two dissimilar metals in contact with a moist substance to touch dissected frog legs. The resulting current made the muscles in the frog legs twitch.  In 1800, Alessandro Volta publishes details of a battery. In 1859, Raymond Gaston Planté made the first lead acid cell by rolling up two strips of lead sheet separated by pieces of flannel, and the whole assembly was immersed in dilute sulphuric acid. Between 1898 to 1908, Thomas Edison, the most prolific of all American inventors, developed an alkaline cell with iron as the anode material (-) and nickelic oxide as the cathode material (+). 
One of the earliest public works gaining attention was enlightening the 1893 Chicago’s World Columbia Exposition with 250,000 light bulbs, and illuminating a bridge over the river Seine during the 1900 World Fair in Paris. The use of electricity may go back further. While constructing a railway in 1936 near Baghdad, workers uncovered what appeared to be a prehistoric battery, also known as the Parthian Battery. The object dates back to the Parthian period and is believed to be 2,000 years old. The battery consisted of a clay jar that was filled with a vinegar solution into which an iron rod surrounded by a copper cylinder was inserted. This device produced 1.1 to 2.0 volts of electricity.
- ↑ http://en.wikipedia.org/wiki/Battery_(electricity)
- ↑ Cadex Electronics. "Battery University: Learn about batteries." 2015. http://batteryuniversity.com/learn/article/when_was_the_battery_invented
- ↑ | Decker,Franco., Department of Chemistry University of Rome "La Sapienza", Electrochemistry Encyclopedia - VOLTA AND THE "PILE", January 2005
- ↑ |All About Batteries dot com, access 2010
- ↑ Cadex Electronics. "Battery University: When was the battery invented?" 2015. http://batteryuniversity.com/learn/article/when_was_the_battery_invented