In generally accessible barrel shaped Leclanche’ cell accessible in the market has following constructional highlights.
- A cylindrical can, made from a thin sheet of zinc, serves as the anode and also holds all the other active and electrolyte materials of the battery.
Ideally, the zinc used in a battery should be 99.99% pure. However, the zinc used to make the zinc-carbon battery container contains 0.03 to 0.06 percent cadmium and 0.02 to 0.04 percent lead. Lead gives zinc an improved quality, and is also a corrosion inhibitor, in addition, cadmium gives zinc strong corrosion resistance.
The zinc used in the zinc-carbon battery should be free from impurities such as cobalt, copper, nickel, iron, as these materials are involved in corrosion reactions with zinc in the presence of electrolyte. Also iron hardens zinc. Impurities like antimony, arsenic, magnesium make zinc brittle.
- The cathode material is manganese dioxide. Manganese dioxide is mixed with acetylene black and wet with an ammonium chloride electrolyte, compressed in a hydraulic machine to form a solid bobbin.The bobbin acts as the positive electrode of the battery. Powdered manganese oxide (MnO2) and powdered carbon black are mixed with water, ammonium chloride (NH2Cl) or/and zinc chloride (ZnCl2). Here, MnO2 is the active cathode material, but is highly electrically resistant, and carbon black powder increases the conductivity of the cathode. Since carbon dust is a good moisture absorbent, it also keeps the wet electrolyte inside the bobbin. The ratio of MnO2 to carbon can vary from 3:1 to 11:1 by weight depending on the battery design. This ratio may even be 1:1 when the battery is designed for flash cameras as the current pulses here are more important than the capacity.
There are not many kinds of manganese dioxide utilized in the dry zinc-carbon battery:
- Regular manganese dioxide (NMD) is accessible in normal minerals of the material. These metals contain 70 to 85 percent manganese dioxide. It must be alpha and beta stage gem structure.
- Artificially incorporated manganese dioxide (CMD) contains 90 to 95 percent of unadulterated manganese dioxide. It has a delta stage precious stone design.
- Electrolytic Manganese Dioxide (EMD). EMD is the most costly contrasted with others yet the most incredible regarding execution. It gives high battery limit, and we use it in hard core modern applications. It has a gamma stage gem structure.Beforehand graphite was utilized as conductive media of cathode bobbin, however presently carbon dark is utilized as it has unique properties of holding wet electrolyte and it gives better compressibility and consistency to the cathode blend. Cells containing carbon acetylene dark in their cathode blend, perform better in inseminated administrations, though cells containing graphite in their cathode blend perform well in high and ceaseless current activity.
- A carbon bar is embedded into this bobbin-molded cathode as an ongoing gatherer from the cathode. The highest point of this carbon pole additionally fills in as the positive person of the cell.We ordinarily make carbon pole with packed carbon. It is profoundly conductive. Carbon commonly it is exceptionally permeable. By wax and oil treatment the carbon is made less permeable up partially when it can forestall wet electrolyte to go through, yet it can go gases through it. We this do as well, that hydrogen and carbon dioxide gases framed during weighty release of the battery can get away from through this carbon bar. The said gases just get this permeable way to go through as we seal the upper part of the bobbin by black-top. That implies a carbon bar in zinc carbon battery likewise fills in as venting entry for the gasses shaped during weighty release.
- An auxiliary washer (non-conductive) is placed above the cathode bobbin.
- Asphalt seal is provided on top of this washer and then there is wax seal on top of asphalt seal.
- The battery has sealing arrangements to prevent electrolyte and water vapor from escaping during its service and storage life.
- After this sealing arrangement, a washer is again placed to hold the sealing material in place.
- This top washer also features a one-piece metal cover, which is mounted over the carbon rod.
- The assembly is now covered with a metal, paper or plastic jacket to give an aesthetic appearance. Labels and ratings are written on the outer cover of the cell.