Carbon-zinc cell, characteristics

Alkaline Primary Cells, Fig. 8 Capacity loss on storage of various miniature alkaline cell systems compared to carbon-zinc and lithium-manganese dioxide cells. The lithium-based cells have significantly better storage characteristics compared to alkaline and carbon-zinc cells... 

Figure 30.9 Voltage characteristics of D-size carbon-zinc cell discharged at three different temperatures with a continuous current drain starting at 667mA (Courtesyof Union Carbide)...

Table 15.3 also shows that certain electrochemical systems, given, the same size are interchangeable, e.g. a lithium cell can replace two carbon-zinc (dry) cells or two silver oxide cells the same goes for three lead-acid cells compared to four alkaline manganese cells. In real life this is only possible to some extent, as certain specific properties of different electrochemical systems regarding their on-load characteristics, their energy content, and special constructive details resist this interchange. Two or three alternatives can always be found and should be evaluated. 

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. 

Figure 6.2 Comparison of discharge characteristics of alkaline manganese and carbon-zinc D-size cells for 500 mA starting, discharged continuously at 21 °C (Courtesy of Union Carbide)...

Lead is sometimes still used in both battery systems. In zinc-carbon batteries it is employed chiefly as an alloying addition to improve the forming characteristics of the zinc can, and additionally acts as a corrosion inhibitor. In alkaline-manganese it has found use as a plating alloy on the brass nail to reduce gassing. In zinc-carbon cells, the lead content is in the order of 0.02% and in those alkaline-manganese batteries where lead is still used, the addition is at a level of a few parts per million. 

The effect of temperature on the available capacity of zinc-carbon (Leclanch6 and zinc-chloride systems) batteries is shown graphically in Fig. 8.28 for both general-purpose (ammonium chloride electrolyte) and heavy-duty (zinc-chloride electrolyte) batteries. At — 20°C typical zinc-chloride electrolytes (25% to 30% zinc-chloride by weight) turn to slush. Below -25°C ice formation is likely. Under these conditions, it is not surprising that performance is dramatically reduced. These data represent performance at flashUght-type current drains (300 mA for a D-size cell). A lower current drain would result in a higher capacity than shown. Additional characteristics of this D-size battery at various temperatures are listed in Table 8.7. 

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