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How do batteries work

01:00 Mon 12th Mar 2001 |

Q.� How do batteries work

asked riley. Thanks to CrankSPL for a very�detailed answer. Here The AnswerBank looks at the subject even further.

Q.� When were batteries first invented

A.� The first battery was created by Alessandro Volta in 1800. The earliest market for batteries was in telegraph systems in the 1830s. More recently, the development of microelectronic technology is the biggest driving force behind the growth of battery technology.

Q. What kind of batteries are there

A.� Batteries are usually classified as primary (batteries which cannot be easily recharged) and secondary (batteries which can be recharged and reused many times).

Q.� So, how do batteries work

A.� Batteries are electrochemical cells. They convert chemical energy to electrical energy using three major materials: the anode, usually made of metal, the cathode, a metallic oxide and the electrolyte, which is an electricity conductor.

All batteries have two terminals, a negative and a positive one. Inside the battery, different chemicals react to produce electrons. These electrons gather at the negative terminal of the battery, flow through the wire and some 'load', a light bulb for example, and then flow back into the battery at the positive terminal. When the electrons flow back into the battery, more chemical reactions occur, producing more electrons, and the cycle repeats itself.

The batteries power is only used when the chemical reaction starts, when electrons are flowing from the negative to the positive terminal.

Q. What chemical reactions go on inside a battery

A.� Basically, oxidation and reduction.

When you switch on, for example a torch, electric currents in the form of electrons power the bulb. That happens because the anode material, zinc gives up two electrons per atom, known as oxidation. This process leaves unstable zinc ions (an ion is an atom that has gained or lost electrons so has a positive or negative charge) behind.

After the electrons do their job and power the light bulb, they re-enter the battery at the cathode. There they combine with the active material, manganese dioxide in a process called reduction.

The electrolyte solution conducts the electrons from the cathode to the anode, completing the circuit.

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By Lisa Cardy

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