How a battery works.

Alright, so my brother asked me how a battery works the other day, thinking he'd get no answer. But I actually remember a thing or two from A-level so here is how a battery works.

Batteries generate electrical current by using chemical reactions to create a movement of electrons through a circuit.

Electrochemical half cells are the main principle behind how a battery works. Half cells begin oxidation-reduction reactions when 2 of them are connected to each other. Neither will react in isolation and must be connected to another cell to begin the redox reactions.

Here is a diagram of 2 half cells joined together, this is a Zinc-Copper cell, known as a Daniell cell.

In this case the +ive electrode is copper and the -ive is zinc.

When the 2 cells are connected, 2 electrons leave the Zinc metal atom.

The resulting zinc ion moves into the Zinc Sulphate solution.

As the cells are connected by a wire between the anode and cathode. The electrons from the zinc electrode, travel through the wire to the positive terminal.

The result, is the reduction of copper ions in the copper sulphate solution on the positive electrode by the electrons coming from the zinc electrode. Copper metal builds up on the positive electrode. With the zinc electrode being constantly degraded.

In a battery, the principle is the same. Except the wire between the positive and negative terminal runs through the electrical device requiring power. Exploiting the movement of electrons from negative to positive and harnessing their electromotive force to power the device.

In most cheap AA batteries, Zinc Carbon half cells are used. Employing the same logic.

There ya go. Interesting? Questions?

Hej då.