Ni-cad batteries

Check the rechargeable Ni-Cad batteries under load (e.g., turn pump on and check voltage at charging jack) before use. 

Nickel-cadmium, or "ni-cad," batteries are popular for use in calculators and portable power tools because, unlike most other dry-cell batteries, they are rechargeable (Figure 18.11). The anode of a ni-cad battery is cadmium metal, and the cathode is the nickel(III) compound NiO(OH) supported on nickel metal. The electrode reactions are... 

Ni-cad batteries can be recharged many times because the solid products of the electrode reactions adhere to the surface of the electrodes. 

The rechargeable nickel-cadmium (Ni-Cad) batteries are used in a variety of cordless appliances such as telephones, battery operated tools, and portable computers. During discharge, cadmium metal (Cd) acts as the anode, and nickel dioxide (Ni02) as the cathode. Both metals form insoluble hydroxides due to the presence of the potassium hydroxide electrolyte. The cell reaction during discharge is... 

The moped looked pretty normal except for a couple of metal boxes— the fuel cell and a NiCad battery—mounted in the frame ahead of and underneath the rider. Kordesch converted the Austrian-made Puch (bought at Sears, Roebuck) in 1966, and he drove it on public roads during his years at Union Carbide. There were two 16-volt, 400-watt hydrazine-air alkaline fuel cells and a Ni-Cad battery. The batteries could be switched in parallel or series for speed control. The range was about 60 miles on 2 liters of a 64 percent aqueous hydrazine, with an easy top speed of 25 miles per hour. 

Even further down the scale are tiny fuel cells that their developers say will power cellular telephones, laptop computers, and electric hand tools. A fuel cell developed by a former Los Alamos weapons specialist, Robert Hockaday, was claimed to be capable of giving about 50 times more talk time when used in a cellular phone than conventional Ni-Cad batteries at... 

Figure 19.4 Nickel-cadmium (ni-cad) batteries. The fundamental components of these batteries are nickel oxide, nickel hydroxide, and nickel metal, cadmium hydroxide and cadmium metal, and potassium hydroxide. 

Nickel is also rather rare. The common U.S. coin called the nickel is mostly composed of copper. It is an alloy that is about 25% nickel. An alloy of chromium and nickel, called nichrome, is a nickel-chromium alloy and is used to make heating elements and wires. Nickel is also used in nickel-cadmium (Ni-Cad) batteries, rechargeable batteries that have been used in laptop computers and other devices. Nickel compounds also display colors, typically green. 

Cadmium is a widely distributed metal used in manufacturing and is present in a number of consumer products. Dietary exposure to cadmium is possible from shellfish and plants grown on cadmium-contaminated soils. Absorption is increased when associated with low levels of iron or calcium in the diet. Some plants, such as tobacco, can concentrate cadmium from even low levels in the soil. The lung readily absorbs cadmium, thus cigarette smokers have elevated cadmium exposure. Cadmium is also used as a metal alloy, in paint, and in batteries (Ni-Cad, nickel-cadmium). Workplace exposure can occur in welding and battery manufacture. 

FIGURE 18.11 Recharge- able nickel-cadmium, or ni-cad, storage batteries. 

Nickel-metal-hydride batteries (Figure 13.17) find use in many of the same devices as ni-cad cells. In this battery, the cathode reaction is the same ... 

All these galvanic cells produce electricity until they run out of a reactant. Then they must be discarded. However, there are cells (batteries) that can be recharged, as the redox reaction can be reversed to regenerate the original reactants. Nickel-cadmium (Ni-Cad) and lithium batteries fall into this category. The most familiar type of rechargeable battery is probably the automobile battery. 

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