Nickel-Cadmium Rechargeable Batteries

Nickel-cadmium rechargeable batteries are being researched. Alternatives such as cadmium-free nickel and nickel hydride systems are also being researched, but nickel-cadmium batteries are unlikely to be totally replaced. Nickel-cadmium batteries can be reprocessed to reclaim the nickel. However, currently, approximately 80% of all nickel-cadmium batteries are permanently sealed in appliances. Changing regulations may result in easier access to these nickel-cadmium batteries for recycling. 

One of cadmiums primary uses is in the manufacture of batteries. Nickel-cadmium batteries, also known as nicad batteries, can be recharged many times with only small losses of efficiency. This makes nicad batteries more durable and longer lasting than rechargeable lead batteries. Nicad batteries are also more convenient... 

The most important example of a secondary cell is the lead storage battery used in automobiles. Other examples of secondary cells are the Edison cell and the nickel-cadmium rechargeable cells used in calculators and flash lamps. 

A second classical example is the use of nickel oxide in the nickel-cadmium rechargeable battery (Figure 9.21). The reactions in this battery are described by the equations... 

Figure 9.21 Nickel-cadmium rechargeable battery, (a) Cover, (b) positive contact, (c) resealable vent mechanism (in the event of a pressure buUd up), (d) positive tab welded to positive contact, (e) insulating seal ring, (f) negative plate, (g) separator, (h) positive plate, (i) negative tab, and (j) nickel-plated steel case. (Reproduced with permission from Ref. [25], 1985, WUey-VCH.)...

In 1859, the French scientist Gaston Plants (1834-1889) made the first prototype of a lead acid rechargeable battery. An alkaline nickel-cadmium rechargeable battery was developed in 1899 by the Swedish engineer W. Jungner (1869-1924) and an alkaline nickel-iron battery was developed two years later by the well-known American inventor Thomas A. Edison (1847-1931). Up to the seventh decade of the nineteenth century, electrochemical batteries remained the only sources of electrical current and power. 

Uses Cobalt salts paint and varnish driers catalyst nickel-cadmium rechargeable batteries brightenerfor plastics and polyester plating... 

The supply to the intruder alarm system must be secure and tbis is usually achieved by an a.c. mains supply and battery back-up. Nickel-cadmium rechargeable cells are usually moimted in tbe soimder housing box. 

Low-Power Zinc-Air Nickel-Metal-Hydride, and Nickel-Cadmium Rechargeable Batteries... 

ANSI C18.2M, Part 1 Standard for Portable Rechargeable CeUs and Batteries Nickel-cadmium Nickel-metal hydride Lithium-ion... 

TABLE 4.9ii> Dimensions of Some Popular Nickel-Cadmium Rechargeable Batteries That Are Interchangeable with Primary Batteries ... 

Similar analyses can be made for specific commercial and industrial applications. For example, the cost of the use of zinc/alkaline/manganese dioxide primary batteries versus nickel-cadmium rechargeable batteries in a typical portable electronic device applications are compared in Table 6.4. If the usage rate is low and the drain rate moderate, the primary battery is more cost-effective besides offering the convenience of not having to be periodically recharged. 

Redox reactions can be reversed to regenerate the original reactants, allowing people to make rechargeable batteries. Nickel-cadmium (Ni-Cad) and lithium batteries fall into this category, but the most familiar type of rechargeable battery is probably the automobile battery. 

Zinc-carbon, alkaline, and mercury cells are primary batteries, which are not rechargeable. Batteries that are rechargeable are called secondary batteries, or storage batteries. A storage battery produces energy from a reversible redox reaction, which occurs in the opposite direction when the battery is recharged. A nickel-cadmium rechargeable battery is an example of a secondary battery. 

Hydrogen-storage alloys (18,19) are commercially available from several companies in the United States, Japan, and Europe. A commercial use has been developed in rechargeable nickel—metal hydride batteries which are superior to nickel—cadmium batteries by virtue of improved capacity and elimination of the toxic metal cadmium (see BATTERIES, SECONDARYCELLS-ALKALINe). Other uses are expected to develop in nonpolluting internal combustion engines and fuel cells (qv), heat pumps and refrigerators, and electric utility peak-load shaving. 

Nickel-cadmium and nickel-iron are prime examples of rechargeable (secondary) batteries, invented in 1901 by Waldemar Jungner and Edison, respectively. In the 1920s and 1930s, such batteries powered radios prior to rural clectrificadnn. The sealed nickel-cadmium battery is now the most widely used battery in consumer products. 

After use, a nickel-cadmium (Nicad) battery has 0.129 g of Cd(OH)2 deposited on the anode. The battery is inserted into a recharger, which supplies 0.175 A. How many hours does the Nicad battery need for recharging so that all the Cd(OH)2 is converted back to Cd Assume that the recharger is 100% efficient. (See Problem 76 for a description of the Nicad battery.)... 

Apart from the improvement and scaling up of known systems such as the lead accumulator or the nickel/cadmium cell, new types of cells have also been developed. Here, rechargeable lithium batteries and nickel-systems seem to be the most promising the reason for this will be apparent from the following sections [3]. 

Compared with nickel-cadmium and nickel-metal hydride systems RAM cells exhibit very low self-discharge, making them ideal for intermittent or periodic use without the need to recharge before using, even in hot climates. Figure 6 shows a comparison of the temperature characteristics, for various battery systems in the form of Arrhenius diagrams. 

At another type of active electrode, found in many batteries, the reaction is the conversion between a metal and an Insoluble salt. At the surface of this type of electrode, metal cations combine with anions from the solution to form the salt. One example is the cadmium anode of a rechargeable nickel-cadmium battery, at whose surface cadmium metal loses electrons and forms cations. These cations combine immediately with hydroxide ions in... 

The following half-reactions occur in the rechargeable nickel-cadmium battery ... 

The relatively simple chemistry of this redox reaction is one reason why nickel-cadmium batteries are rechargeable. As we show later in this chapter, applying an external voltage can reverse this reaction. 

The nickel-cadmium battery is another common battery that can be recharged. As described in Example, nickel and cadmium are the working substances in this battery ... 

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