Question

What is dry cell ?....

Answer 1

We are using the term 'Dry cell' because the chemicals used are not in the form of liquid, but in the form of liquid-paste or gel. The other examples of primary cells are voltaic cell, leclanche cell, Deniel cell. The primary cells supply a voltage of 1.5 V - 3 V. These cells are used in torches, radios, electric clocks, toys,etc.

Hope it's helps you.

Answer 2

A dry cell is a DC battery. It is usually small and portable. Its voltage is also usually a few volts. Most common are AAA, AA, A sized. They give 1.5 V. Dry cell was invented by Carl Gassner in 1886. Dry cells are sealed very well. They do not contain a liquid electrolyte. So the electrolyte does not overflow.  Dry cells are primary cells and are not rechargeable. Small dry cell (Alkaline or Lithium ion) batteries are used inside toys, Laptops and phones.

 

A battery is an electrical device that supplies or maintains a constant potential difference in a circuit. The battery converts the chemical energy stored inside it into electrical energy. It is also called an electromotive force. Such a battery is called a DC (direct current) battery - the current flows in one direction only, when the battery is driving the circuit.

A cell has two electrical terminals; one is called positive terminal and the other, the negative terminal. The positive terminal is at a higher potential. The current in the circuit flows from positive terminal towards negative terminal. Electrons move from negative terminal towards the positive. 

Inside the battery, the terminals are attached to metallic plates on which positive or negative ions accumulate. That gives rise to the potential. A battery has a life time. When all the positive charges from the cathode plate move to the anode plate, the battery is discharged. It cannot supply any more voltage. There is an electrolyte between the anode and cathode that facilitates movement of ions (charges).

A battery can be a primary cell or secondary. Primary cells cannot be recharged as the chemical reaction inside the battery cannot be reversed. In secondary cells, the chemical reaction is reversible and so the battery can be recharged using another energy source, a few hundreds or thousands of times.

Lithium batteries (small size) are used in electronic gadgets. Zinc carbon batteries and nickel-cadmium cells too are used as dry cells.

 

One of these elements (zinc for example) is the anode and the other (carbon) is the cathode. In this example, Ammonium Chloride paste acts as the electrolyte (the medium for ions to travel).
A battery is sealed in a highly electrically insulating packing material to prevent leakage.

See the diagram for a typical a dry cell battery.