Cell voltage nickel zinc

The actual cell voltage is about 1.5 V, it does not depend on the actual pH-value of the electrolyte solution as obvious from the absence of protons and hydroxide ions in the cell reaction equation. It slightly depends on the source of the used manganese dioxide. Initially naturally occurring manganese dioxide was used. The battery required a quality of less than 0.5% copper, nickel, cobalt, and arsenic to avoid undue corrosion of the zinc electrode. Currently synthetic manganese dioxide is prepared either by chemical (CMD) or electrochemical (EMD) procedures. For improved electrical conductivity graphite or acetylene black are added. Upon deep... 

The nickel—zinc combination has a high cell voltage (about 1.75 V), which results in a very favorable energy density compared to that of nickel—cadmium or lead—acid. Additionally, zinc is relatively inexpensive and, in the absence of mercury additive, is environmentally benign. The nickel—zinc system was discussed as early as 1899 (4). There has been a resurgence of interest in the system for electric vehicles, but the problems of limited cycle life have not been completely overcome. 

The first systems to be examined are the nickel/iron and the nickel/zinc systems. Values ranging from 60 to 80kWh/kg seem realizable, without regard to life expectancy. The nickel/iron and nickel/zinc systems will always be more expensive than a comparable lead-acid battery for the following three reasons the materials involved are more expensive, the production involves more expenditure, which is partly the case because a greater number of cells are required for the same voltage, and more cells are needed because each cell yields less voltage. So to be more... 

FIGURE 31.18 EOC voltage as a function of charging current and temperature for a 30 Ah single-cell nickel-zinc battery. Courtesy of Eve reel Corp.)... 

I There are only two alternative battery systems which could currently be considered feasible for SLI applications nickel-cadmium and nickel-zinc. However, both are much costlier and have a lower cell voltage than lead-acid systems. Other possible technologies are either technically unproven, or have at least one major operating drawback in SLI use. Manders et al, ELDC (1990). 

Until recently one company (Yardney) offered a range of vented nickel-zinc cells in the capacity range 2 to 35 Ah at a working voltage of 1.6 V per cell. Typical characteristics of a 5 A h nickel zinc battery are shown... 

Nickel-zinc cells have a voltage of 1.85 V at 25°C and a high energy density (75Wh/kg", 150Wh/dm ). 

Figure 33.5 Typical charge curve (voltage versus percentage capacity) of a Yardney NZ EV6 (FIAT) nickel-zinc cell at 25°C and 25A charge rate (Courtesy of Yardney)...

Table 12-11 predicts the cell will operate so as to dissolve metallic zinc and deposit metallic nickel, and its voltage will be +0.51 volt This is exactly what occurs in such a cell. Predicting is fun— let s try it again Another cell we studied is based on reaction (52) ... 

Numerous other types of cells exist such as zinc-air, aluminum-air, sodium sulfur, and nickel-metal hydride (NiMH). Companies are on a continual quest to develop cells for better batteries for a wide range of applications. Each battery must be evaluated with respect to its intended use and such factors as size, cost, safety, shelf-life, charging characteristics, and voltage. As the twenty-first century unfolds, cells seem to be playing an ever-increasing role in society. Much of this is due to advances in the consumer electronics and the computer industry, but there have also been demands in numerous other areas. These include battery-powered tools, remote data collection, transportation (electric vehicles), and medicine. 

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