What is Battery?
[[File:A Cell and a Battery symbol.svg|thumb|205x205px|Schematic symbol of a battery]] {{about|electrical batteries|the crime of battery|battery (tort)}} [[File:Batteries comparison 4,5 D C AA AAA AAAA A23 9V CR2032 LR44 matchstick-1.jpeg|350px|thumb]] A '''battery''' converts [[chemical energy]] into [[electrical energy]] by a [[chemical reaction]]. Usually the chemicals are kept inside the battery. It is used in a [[circuit]] to power other [[component]]s. A battery produces [[direct current]] (DC) electricity (electricity that flows in one direction, and does not switch back and forth). Using the [[electricity]] from an outlet in a building is cheaper and [[energy efficiency|more efficient]], but a battery can provide electricity in areas that do not have [[electric power distribution]]. It is also useful for things that move, such as [[electric vehicle]]s and [[mobile phone]]s. Batteries may be [[Primary cell|primary]] or [[Secondary cell|secondary]]. The primary is thrown away when it can no longer provide electricity. The secondary can be recharged and reused. == The chemistry inside a battery == A Battery can be one ''cell'' or many ''cells''. Each cell has an [[anode]], [[cathode]] and [[electrolyte]]. The electrolyte is the main material inside the battery. It is often a type of acid, and can be dangerous to touch. The anode reacts with the electrolyte to produce [[electrons]] (this is the ''negative'' or ''-'' end). The cathode reacts with the electrolyte and takes electrons (this is the ''positive'' or ''+'' end).<ref>{{cite web|title=Battery Reactions and Chemistry|date=April 2000 |url=http://electronics.howstuffworks.com/everyday-tech/battery3.htm|publisher=How Stuff Works|accessdate=13 April 2013}}</ref> An [[electric current]] happens when a wire connects the anode to the cathode, and the electrons move from one end to the other. (But a battery can be damaged by just a wire connecting the two ends, so a ''load'' is also needed between the two ends. The load is something that slows the