Zinc Carbon Battery Cell Construction and Working

The zinc-carbon battery cell is a variety of dry cell. It is basically a primary cell. Furthermore, principally this cell is similar to a Leclanche battery cell. The only difference is that instead of using liquid aqueous ammonium chloride electrolyte we use here porous paper soaked with the same solution. Due to this arrangement, we can solve the problem of spilling. So, we can avoid the falling of liquid electrolyte when we align the battery inclined. Therefore, we can use a zinc-carbon battery in an inclined or a horizontal position. This property of the cell made it very much popular for using it in various type of household gadgets. Even a few decades ago we used to use zinc-carbon battery dry cells in our maximum types of battery-operated gadgets and instruments.

Construction of Zinc-Carbon Battery Dry Cell

There is a zinc container holds all the materials of the battery inside it. A paper strip bearing manufacturer name, manufacturer logo, ratings and other pieces of necessary information covers the container from outside. The paper cover serves for two purposes. It provides insulation to the body of the cell. Also, it gives an aesthetic look to the zinc-carbon battery cell. The zinc container serves as the negative electrode (anode) of the battery.

zinc carbon dry battery cell

Along the inner wall of the zinc container, there is a thick porous paper board, shocked with ammonium chloride aqua solution. The ammonium chloride is the electrolyte of the cell.

We fill the space inside the porous paper with a mixture of powdered carbon and manganese dioxide. The manganese dioxide is actually the positive electrode (cathode) material of the cell. The carbon dust present in the mixture improves the conductivity of the cathode material. Also, we immerse a carbon rod in the cathode material to facilitate better conductivity of the cathode with the external circuit. A small copper cap covers the projected portion of the carbon rod on the top of the cell.

A thermoplastic cover seals air tightly the top opening of the cell. This sealing arrangement prevents the aqueous electrolyte from vaporization.

Working Principle of Zinc-Carbon Battery Dry Cell

Whenever we connect a load between the negative and positive terminals of the cell the following oxidation-reduction reactions take place.

Anode Oxidation Reaction

On the inner wall of the container, zinc atoms come out in the electrolyte by living electrons behind.

Then, in the electrolyte, ammonium and chloride ions present.

Positive zinc ions combine with negative chloride ions to form zinc chloride.

Cathode Reduction Reaction

The manganese dioxide of the cathode reacts with the ammonium ions in the presence of water and forms manganese oxide with ammonium hydroxide.

Overall Reaction

Reference: – Wikipedia

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