Leclanche Zinc-Carbon Batteries

The manganese-zinc batteries are manufactured as leak-proof dry batteries having the electrolyte soaked up by a matrix. 

The first zinc-carbon cell made in 1865 by the French engineer G.-L. Leclanche was a glass jar containing an aqueous solution of ammonium chloride into which were immersed an amalgamated zinc rod (the negative electrode) and a porous earthenware pot packed with a mixture of manganese dioxide and powdered coke and containing a carbon-rod current collector at the center (positive electrode). Quite soon a zinc can served as the anode and cell container replaced the zinc rod. 

the electrode processes occurring in manganese-zinc batteries with salt electrolytes are complicated, and their thermodynamic analysis is difficult. In a rough 

From the 1960s onward, alkaline manganese-zinc batteries started to be produced. They have appreciably better electrical performance parameters but do not differ in their operating features from the Leclanche batteries, are produced in identical sizes, and can be used interchangeably with them. Thus, a gradual changeover occurred and the phase-out of the older system is now almost complete. 

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FIGURE 8.8 Typical discharge curve of a Leclanche zinc-carbon battery. 

A common dry cell battery is the zinc-carbon battery, using dry Leclanche cell, with a nominal voltage of 1.5 volts. 

Zinc-Carbon Battery. The Leclanche or zinc-carbon dry cell battery has existed for over 100 years and had been the most widely used of all the dry cell batteries because of its low cost, relatively good performance, and ready availability. Cells and batteries of many sizes and characteristics have been manufactured to meet the requirements of a wide variety of applications. Significant improvements in capacity and shelf life were made with this battery system in the period between 1945 and 1965 through the use of new materials (such as beneficiated manganese dioxide and zinc chloride electrolyte) and cell designs (such as the paper-lined cell). The low cost of the Leclanchd battery is a major attraction, but it has lost considerable market share, except in the developing countries, because of the newer primary batteries with superior performance characteristics. 

ZINC-CARBON BATTERIES (Leclanche and Zinc Chloride Cell Systems) ... 

During this transitional phase, the zinc-carbon batteries can be classified into two types, Leclanche and zinc chloride. These can, in turn, be subdivided into separate general purpose and premium battery grades, in both pasted and paper-lined constructions ... 

Closed-Circuit Voltage. The closed-circuit voltage (CCV), or working voltage, of the zinc-carbon battery is a function of the load or current drain the cell is required to deliver. The heavier the load or the smaller the circuit resistance, the lower the closed-circuit voltage. Table 8.4 illustrates the effect of load resistance on the closed-circuit voltage for D-size batteries in both the Leclanche and zinc-chloride systems. 

Performance of zinc-carbon batteries varies depending upon the type of discharge. The performance of Leclanche batteries is significantly better when used under intermittent compared to continuous discharge conditions, because (1) a chemical recuperation reaction replaces a small portion of active ingredients during the rest periods and (2) transport phenomena redistribute reaction products. ... 

Zinc-carbon batteries are made in a number of different sizes with different formulations to meet a variety of applications. The single-cell and multicell batteries are classified by electrochemical system, either Leclanche or zinc chloride, and by grade general purpose, heavy duty, extra heavy duty, photoflash, and so on. These grades are assigned accortUng to their output performance under specific discharge conditions. 

The electrolyte was a solution of ammonium chloride that bathed the electrodes. Like Plante s electrochemistry of the lead-acid battery, Leclanche s electrochemistry survives until now in the form of zinc-carbon dry cells and the use of gelled electrolyte.12 In their original wet form, the Leclanche electrochemistry was neither portable nor practicable to the extent that several modifications were needed to make it practicable. This was achieved by an innovation made by J. A. Thiebaut in 1881, who through encapsulating both zinc cathode and electrolyte in a sealed cup avoided the leakage of the liquid electrolyte. Modern plastics, however, have made Leclanche s chemistry not only usable but also invaluable in some applications. For example, Polaroid s Polar Pulse disposable batteries used in instant film packs use Leclanche chemistry, albeit in a plastic sandwich instead of soup bowls.1... 

D—Leclanche Zinc anode Carbon, silver chloride, and air Primary and secondary Zinc—air batteries, carbon—zinc batteries, and silver chloride-zinc batteries... 

Cost The cost of the battery is determined by the materials used in its fabrication and the manufacturing process. The manufacturer must be able to make a profit on the sale to the customer. The selling price must be in keeping with its perceived value (tradeoff of the ability of the user to pay the price and the performance of the battery). Alkaline primary Zn—MnOz is perceived to be the best value in the United States. However, in Europe and Japan the zinc chloride battery still has a significant market share. In developing countries, the lower cost Leclanche carbon—zinc is preferred. Likewise, lead acid batteries are preferred for automobile SLI over Ni—Cd with superior low-temperature performance but with a 10 times higher cost. 

Primary Zinc/carbon (Leclanche) 2Mn02 + H20 + 2e —> Mn203 + 20H Zn— Zn2+ + 2e NH4Cl/ZnCl2/ Mn02/damp C powder Graphite Zn 1.55 Portable voltage sources (dry batteries)... 

Camacho cell — This was a - chromic acid battery with zinc anodes, and a construction that the chromic acid solutions flowed through the cathode compartment housing the inert carbon electrodes. See also - Daniell cell, - zinc, - Zn2+/Zn electrodes, - Zn2+/Zn(Hg) electrodes, - zinc-air batteries (cell), and - Leclanche cell. Ref [i] Hauck WP (1883) Die Galvanischen Batterien, Accumulatoren und Thermosaulen, 2nd edn. Hartleben s Verlag Wien... 

See also - Leclanche cell, -> Zn2+/Zn electrodes, -> Zn2+/Zn(Hg) electrodes, -> zinc-air batteries (cell), -> zinc-carbon cell, -> zinc electrowinning. 

Nernst equation (20.7) zinc-carbon (Leclanche) dry cell (20.8) alkaline dry cell (20.8) lithium-iodine battery (20.8) lead storage cell (20.8) nickel-cadmium cell (20.8)... 

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