A battery is a self-contained, chemical power pack that canproduce a limited amount of electrical energy wherever it's needed.Unlike normal electricity, which flows to your home through wiresthat start off in a power plant, a battery slowly converts chemicalspacked inside it into electrical energy, typically released over. The basic power unit inside a battery is called a cell, andit consists of three main bits. There are two electrodes (electrical terminals)and a chemical called an electrolyte in between. It's important to note that the electrodes in a battery are alwaysmade from two dissimilar materials(so never both from the same metal), which obviously have to be conductors of electricity.This is the key to how and why a battery.