Flat-cell Leclanche battery

Figure 10.17 Construction of a flat cell Leclanche battery.

Manganese dioxide, Mn02, (MDO) is a widely used as material in primary electrochemical cells. It is the positive electrode of the zinc-MnOa cell, invented in 1866 by the French engineer Georges-Lionel Leclanche [11]. Li-MnOa battery was developed by Sanyo in 1975 [12] as low-power supplies for watches, calculators and memory backups. The poor cyclability of MDOs observed at that time [13] has been improved by preparing composite dimensional manganese oxides (CDMOs) for the development of flat-type secondary batteries. Table 6.2 lists the chemical formula of selected Li-Mn-O compounds used in Li batteries. 

Fig. 3.10 (a) Cross-section of a flat Leclanche cell, (b) 9 V battery of six flat Leclanche cells. (By courtesy of Berec.)... 

Leclanche s cells are produced in cylindrical and flat (prismatic) designs in different sizes. Their energy density at 20 °C is very low (65 Wh kg-1 for the cylindrical size, see Table 2) compared to the other primary battery technologies. Fiowever, they are the cheapest batteries available in the market (see Table 2). Their nominal voltage is 1.5 V, which is comparable with other battery technologies (see Table 2). 

Figure 3.2. Typical battery discharge curves. 1— Steep discharge curve typical, for example, for Leclanche cells 2— flat discharge curve typical, for example, for mercury-zinc cells 3—discharge curve with initial dip typical, for example, for thionyl chloride-hthium cells.

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