A battery is basically a mini-power plant, converting a chemical reaction into electrical energy. Dry cell (alkaline) batteries can differ in several ways, but they all have the same basic components.

A steel casing that houses the cathode components

This is a mixture of manganese dioxide and carbon. Cathodes are the electrodes that are reduced by the electrochemical reaction

The separator is a non-woven, fibrous fabric that keeps the electrodes apart

A powdered zinc metal. Whilst the cathodes are reduced, the anodes are the
electrodes that are oxidised in the reaction

These are where the electrochemical reaction takes place

This is a potassium hydroxide solution in water and acts as the medium for
the movement of ions within the cell. It also carries the ionic current inside the battery

A simple brass pin in the middle of the cell that conducts electricity to the outer circuit