How Electricity Is Produced By A Battery?
Electric current for power can be produced in two ways. It can be produced by machines called “dynamos”, or “generators” and by battery cells. A battery cell produces electricity by changing chemical energy into electrical energy. Part of the chemical energy is of course changed into heat as well.
There are two kinds of battery cells. One is called a “primary cell”. It cannot be renewed when it is used except by replenishing its chemicals. The ordinary dry cell, the cell used in torch, calculator, or flashlight is of this type. The other type is called “a secondary cell”. This cell can be recharged by sending an electric current through it. The storage cells, used to start the automobiles are covered under this category.
A battery is a group of cells – two or more; primary or secondary cells. A single cell does not constitute a battery; various chemicals are used in primary cells but under the same principle. In every primary cell there are electrodes and an electrolyte. The electrodes or “cell elements” as we generally call them have two different metals or one metal and carbon. The electrolyte is a liquid.
One of the elements, called “the Cathode” is usually zinc. The other is called “the anode” and is usually carbon. Chemical action causes the cathode to dissolve slowly in the electrolyte. This sets the electrons free. Now if a path or circuit is provided for the free passage of these electrons, they provide an electric current. The connection of elements by a wire or some other electrical conductor makes the current flow and we have electricity.
In the case of a storage battery, the current is not actually stored anywhere in the system. Its power is provided by the chemical changes, just as all other cells do. One set of plates in a storage battery is made of metallic lead and the other of lead peroxide. Both sets are immersed in Sulphuric acid, and both gradually change to lead Sulphate. It is this chemical process which produces electric current in a storage battery.