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Energy nickel-cadmium

From these data, the hydride cells contain approximately 30—50% more capacity than the Ni—Cd cells. The hydride cells exliibit somewhat lower high rate capabiUty and higher rates of self-discharge than nickel—cadmium cells. Life is reported to be 200—500 cycles. Though not yet in full production it has been estimated that these cells should be at a cost parity to nickel—cadmium cells on an energy basis. [Pg.563]

Dry cells (batteries) and fuel cells are the main chemical electricity sources. Diy cells consist of two electrodes, made of different metals, placed into a solid electrolyte. The latter facilitates an oxidation process and a flow of electrons between electrodes, directly converting chemical energy into electricity. Various metal combinations in electrodes determine different characteristics of the dry cells. For example, nickel-cadmium cells have low output but can work for several years. On the other hand, silver-zinc cells are more powerful but with a much shorter life span. Therefore, the use of a particular type of dry cell is determined by the spacecraft mission profile. Usually these are the short missions with low electricity consumption. Diy cells are simple and reliable, since they lack moving parts. Their major drawbacks are... [Pg.1076]

The reciprocal value, / = l/V/Ah of the coulometric efficiency is called the charging factor. The coulometric efficiency for electrochemical energy conversion is about 70-90 percent for nickel/cadmium and nearly 100 percent for lithium-ion accumulators [14]. [Pg.18]

For many years, sintered-nickel electrodes have been used as the positive electrodes for sealed-type nickel-cadmium batteries. With an increase in the demand for high energy density, this type of elec-... [Pg.26]

Cadmium presents an environmental risk. Since small nickel-cadmium cells are often not separately disposed of, they may enter municipal garbage incinerators. The search for alternative materials for the negative electrode led to metal hydrides, which not only are regarded as environmentally less critical, but also allow higher energy density than cadmium. This is especially important for use in portable equipment, such as cellular phones or lap-... [Pg.284]

The thermodynamic properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries, as it may provide a considerably higher energy density than the commonly used lead-acid and nickel-cadmium systems, while in contrast to Pb and Cd, magnesium is inexpensive, environmentally friendly, and safe to handle. However, the development of Mg-ion batteries has so far been limited by the kinetics of Mg " " diffusion and the lack of suitable electrolytes. Actually, in spite of an expected general similarity between the processes of Li and Mg ion insertion into inorganic host materials, most of the compounds that exhibit fast and reversible Li ion insertion perform very poorly in Mg " ions. Hence, there... [Pg.329]

In 1899, the nickel-cadmium battery, the first alkaline battery, was invented by a Swedish scientist named Waldmar Jungner. The special feature of this battery was its potential to be recharged. In construction, nickel and cadmium electrodes in a potassium hydroxide solution, it was the first battery to use an alkaline electrolyte. This battery was commercialized in Sweden in 1910 and reached the Unites States in 1946. The first models were robust and had significantly better energy density than lead-acid batteries, but nevertheless, their wide use was limited because of the high costs. [Pg.1306]

The sealed nickel-metal hydride cell (more consistently metal hydride-nickel oxide cell) has a similar chemistry to the longer-established hydro-gen-nickel oxide cell considered in Chapter 9. In most respects (including OCV and performance characteristics), it is very similar to the sealed nickel-cadmium cell, but with hydrogen absorbed in a metal alloy as the active negative material in place of cadmium. The replacement of cadmium not only increases the energy density, but also produces a more environmentally friendly power source with less severe disposal problems. The nickel-metal hydride cell, however, has lower rate capability, poorer charge retention and is less tolerant of overcharge than the nickel-cadmium cell. [Pg.177]

Nickel-melal hydride cells can be discharged at the 2 C rate (and in some cases at 4 C) and charged at 1 C. An AA-sized cell with a nominal capacity of over 1 Ah can thus be discharged at over 2 A and with a peak current of over 10 A. The energy density is highly dependent on rate, but for comparable conditions is 25% higher than an equivalent nickel-cadmium cell. Fig. 6.12 shows a comparison of the discharge characteristics of these two systems. [Pg.179]

Replacing zinc with cadmium reduces the OCV by approximately 0.4 V, but increases the cycle life of the system considerably. This cell is very similar to the nickel-cadmium system, but has an energy density higher by about a third. The cost of the system has restricted its application to small button cells. [Pg.196]


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See also in sourсe #XX -- [ Pg.658 , Pg.663 ]




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