General purpose batteries are mostly used for home appliances and they may use ammonium chloride and/or zinc chloride as the electrolyte. These batteries are used for different applications as here below;
Clocks Car Alarms
Flash Lights Remote Controls
A zinc–carbon battery is a dry cell battery that delivers a potential of 1.5 volts. Although carbon is an important element of the battery’s construction, it takes no part in the electrochemical reaction. The cell could more properly be called a “zinc–manganese” cell. The zinc can is the anode and the source of high potential electrons and hence is marked positive to designate its higher potential. The manganese dioxide and carbon black paste is the cathode and the inert carbon rod is a non-corrodible conductor. General purpose batteries may use ammonium chloride and/or zinc chloride as the electrolyte.
Zinc–carbon batteries were the first commercial dry batteries, developed from the technology of the wet Leclanché cell, and made flashlights and other portable devices possible, because the battery can function in any orientation. They are still useful in low drain or intermittent use devices such as remote controls, flashlights, clocks or transistor radios. Zinc–carbon dry cells are single-use primary cells, since they are not intended to be recharged.
The container of the zinc–carbon dry cell is a zinc can. The can contains a layer of NH4Cl or ZnCl2 aqueous paste impregnating a paper layer that separates the zinc can from a mixture of powdered carbon (usually graphite powder) & manganese (IV) oxide (MnO2) which is packed around a carbon rod. Carbon is the only practical conductor material because every common metal will quickly corrode away in the positive electrode in salt based electrolyte.
Cross-section of a zinc–carbon battery.
Early types, and low-cost cells, use a separator consisting of a layer of starch or flour. A layer of starch-coated paper is used in modern cells, which is thinner and allows more manganese dioxide to be used. Originally cells were sealed with a layer of asphalt to prevent drying out of the electrolyte; more recently a thermoplastic washer sealant is used. The carbon rod is slightly porous, which allows accumulated gas to escape while retaining the water for the electrolyte. The ratio of manganese dioxide and carbon powder in the cathode paste affects the characteristics of the cell; more carbon powder lowers the internal resistance, but more manganese dioxide improves capacity.
Flat cells are also made for assembly into batteries with higher voltages, up to about 450 volts. A number of flat cells are stacked up, and the whole assembly is coated in wax to prevent evaporation of water from the electrolyte.
Zinc chloride cell
The zinc chloride cell is an improvement on the original zinc–carbon cell, using purer chemicals and giving a longer life and steadier voltage output as it is used. These cells are usually marketed as heavy-duty, extra-heavy-duty, or even super-heavy-duty batteries, and offer about twice the service life of general purpose zinc–carbon cells, or up to four times in continuous-use or high-drain applications.
However, the “heavy duty” moniker is misleading in comparison to alkaline batteries,which offer up to eight times the battery life of heavy duty batteries, especially in continuous-use or high-drain applications.
Manufacturers recommend storage of zinc–carbon batteries at room temperature; storage at higher temperatures reduces the expected service life. While batteries may be frozen without damage, manufacturers recommend that they be returned to normal room temperature before use, and that condensation on the battery jacket must be avoided.