That's got to be the most practical approach. They have a really comprehensive article that would take us weeks to match with regular posting. If further clarification is needed, feel free to ask here.
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A battery is a device which performs the function of simply mantaining a potential difference between its two terminals. The potential is created by the reactions that take place within it. Because of this potential that is created there is a disturbance created within the wire which causes a current to flow through the wire.