Primary zinc-air cells

A series of primary zinc-air cells are developed with capacity ranging from 100 Ah to 3300 Ah and nominal currents ranging from 2 A to 50 A. Technologies for the production of the air electrodes, porous zinc electrodes and for the assembling of the cells are elaborated. Some of the developed zinc-air cells are in production since 1981. 

High power primary zinc-air cells are also developed with nominal current 20A -v 40A and capacity in the range 100 Ah -v 320 Ah. Typical application of these powerful zinc-air cells is as easy activated reserve power supply. These cells also can be successfully used for traction. 

In Fig. 17 we have presented the current-voltage and the power characteristics of 12-cells battery from the cells type ZV300. It must be reminded that, when the zinc anode in the primary zinc-air cells is discharged, the cell is out of operation. By this, the air electrodes, which in principle can operate for a long time, are lost. In order to avoid this inconvenience, mechanically rechargeable zinc-air cells were developed [14]. The essential feature of the mechanically rechargeable zinc-air cell is that the air electrodes are used many times. 

A variety of primary zinc-air cell and batteries are designed with capacity ranging from 100 Ah to 3300 Ah, operating at nominal currents from 2 to 40A at temperatures in the range +40 -t- -40°C. Mechanically rechargeable zinc-air cell are also developed and tested in experimental electric cars and scooters. 

The primary zinc—air cells have captured the hearing aid market, but the rechargeable zinc—air battery is still in the developmental stage. 

High power primary zinc-air cells are also developed with nominal current 20A 40A and capacity in the range 100 Ah 320 Ah. Typical... 

FIGURE 38.2 Design of a Prismatic Primary Zinc-Air Cell Courtesy of Electric Fuel Corp.)... 

FIGURE 38.4 Discharge curves for prismatic primary zinc/air cells at 25°C. (a) High-rate cell, (b) Large-capacity cell. ( Courtesy of Matsi, Inc.y ... 

Other alkaline primary cells couple zinc with oxides of mercury or silver and some even use atmospheric oxygen (zinc—air cell). Frequendy, zinc powder is used in the fabrication of batteries because of its high surface area. Secondary (rechargeable) cells with zinc anodes under development are the alkaline zinc—nickel oxide and zinc—chlorine (see Batteries). 

With regard to cylindrical manganese and alkaline dry cells, which account for some 98% (on a weight basis) of all primary cells sold in Japan, no mercury has been used in the production since 1992. Furthermore, as the production of mercury cells was stopped at the end of 1995, the amount of mercury contained in the dry cells sold in Japan was equal to 1.4 tons in 1997, i.e. only 3% with respect to the 1985 s total (45 tons). In addition, as button type cells (alkaline, silver oxide and zinc-air cells) still contain a small amount of mercury, BAJ will continue to reduce it and promote the collection and recycling of spent dry cells. 

Alkaline Primary Cells, Fig. 10 Discharge characteristics of the zinc-air cell at 0 °C, 21 °C, and 40 °C at the 75-h rate. The constant voltage maintained during discharge is best for hearing aid applications (Courtesy of Duracell)... 

When discussing cathodes for primary cells, it is important to make a distinction between solid materials, mentioned above, and those in which the cathode electrochemical component is not in the physical electrode structure, but rather exist in a liquid or gas state. Examples include zinc air cells, lithium thionyl chloride cells, and lithium sulfur dioxide cells. In each case, the physical cathode stmcture serves as a catalytic reaction... 

Primary Battery Design, Fig. 9 Cross section of a zinc air cell... 

The performance advantages of several types of lithium batteries compared with conventional primary and secondary batteries, are shown in Secs. 6.4 and 7.3. The advantage of the lithium cell is shown graphically in Figs. 7.2 to 7.9, which compare the performance of the various primary cells. Only the zinc/air, zinc/mercuric oxide, and zinc/silver oxide cells, which are noted for their high energy density, approach the capability of the lithium systems at 20°C. The zinc/air cell, however, is very sensitive to atmospheric conditions the others do not compare as favorably on a specific energy basis nor at lower temperatures. 

FIGURE 38.11 Discharge characteristics for primary zinc/air single-cell batteries, a) 35 Ahr prismatic cell, b) 5 Ahr prismatic cell and c) 5 Ahr AA cell. Data from US Army tests. 

J. Passanitti, Development of a High Rate Primary Zinc-Air Cylindricril Cell, Proc. 5th Workshop for Battery Exploratory Development, Burlington, VT, 1997. 

Figure 1. Discharge curve of a primary button air - zinc cell PR-44 at the resistance 625 land at 293 K.

Another interesting nickel-based system is the nickel-hydrogen cell, a hybrid system similar to the zinc-air primary cell described in Section 2.3.1, under Zn-based systems . The cell and its reaction are ... 

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