Batteries nickel-metal

OPTIMIZED RECYCLING PROCESSES FOR ADVANCED BATTERIES Nickel/Metal Hydride (Ni/MH)... 

The demand for the lanthanoid metals is expected to increase with the growing demands for pollution control catalysts in motor vehicles and rechargeable batteries. Along with lithium-ion batteries, nickel-metal hydride (NiMH) batteries find increasing applications in mobile phones, laptop computers and other portable electronic devices such as MP3 players. 

But the problem can be solved, as has been shown by the development groups of rechargeable lithium-ion batteries. Nickel/metal hydride cells (having 50% more capacity and no cadmium content) had just started to penetrate the market to the debit of nickel/cadmium cells, and are being pushed away now by rechargeable lithium-ion batteries. Main applications are cellular phones, mobile phones, and video cameras. It cannot yet be foreseen whether nickel/cadmium will disappear from the market, because they cannot be substituted for in the use in tools. Never in the past has a new battery system eliminated an established system totally. 

Besides being environmentally friendher than Nicad batteries, nickel-metal hydride batteries have a higher energy content per unit mass. This is called the battery s energy density with units expressed in watt-hour/kg. These batteries are commonly used in hybrid electric cars and buses. 

A polymer electrolyte is also referred to as a solid solvent that possesses ion transport properties similar to that of the common liquid ionic solution. It usually comprises a polymer matrix and electrolyte, wherein the electrolyte such as a lithium salt dissolves in a polymer matrix. The research and development of polymer electrolytes have drawn great attention in the last three decades as they are applied in many electrochemical devices such as hthium batteries, nickel - metal hydride (Ni/MH) batteries, fuel cells/direct methanol fuel cells, supercapadtors, electrochromic devices and the like (Gray, 1991 Stephan, 2006). 

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. 

The aimual production value of small, sealed nickel—cadmium cells is over 1.2 biUion. However, environmental considerations relating to cadmium are necessitating changes in the fabrication techniques, as well as recovery of failed cells. Battery system designers are switching to nickel —metal hydride (MH) cells for some appHcations, typically in "AA"-si2e cells, to increase capacity in the same volume and avoid the use of cadmium. 

H. Ogawa, M. Ikoma, H. Kawano, and I. Matsumoto, "Metal Hydride Electrode for High Energy Density Sealed Nickel—Metal Hydride Battery," Proceedings of the 16th International Power Sources Conference, UK, 1988. 

Nickel-metal hydride is a popular alternative to Nicad batteries since they are capable of operating 75 percent longer after each charge, are less likely to suffer memoiy effects, and pose less of an environmental disposal problem. The difference between nickel-metal and Nicad batteries is that the negative... 

Lithium-Ion Cells. Lithium-ion cells and the newer alternative, lithium-ion-polymer, can usually run much longer on a charge than comparable-size Nicad and nickel-metal hydride batteries. Usually is the keyword here since it depends on the battery s application. If the product using the battery requires low levels of sustained current, the lithium battery will perform very well however, for high-power technology, lithium cells do not perform as well as Nicad or nickel-metal hydride batteries. 

Nickel-Hydrogen, Nickel-Iron, and Nickel-Metal Hydride. First developed for communication satellites in the early 1970s, nickel-hydrogen batteries are durable, require low maintenance, and have a long life expectancy. The major disadvantage is the high initial cost. For these batteries to be a viable option for electric vehicles, mass production techniques will have to be developed to reduce the cost. 

A more appropriate battery for transportation applications is probably a nickel-iron or nickel-metal hydride battery. These batteries are not as susceptible to heat and gassing as lead-acid batteries, so they can better withstand high current or high voltage charges that can dramatically shorten charging time. 

GM began offering more expensive nickel-metal hydride batteries as an option. These batteries extended the range to 75 to 130 miles, but also took slightly longer to recharge. 

Zinc/carbon and alkaline/manganese cells are primary battery systems lead, nickel/cadmium, and nickel/metal hydride accumulators are secondary batteries with aqueous electrolyte solutions. Their per-... 

Secondary batteries can be electrically charged, and these batteries can offer savings in costs and resources. Recently, lithium-ion and nickel-metal hydride batteries have been developed, and are used with the other secondary batteries, such as nickel-cadmium, lead-acid, and coin-type lithium secondary batteries. 

The variety of practical batteries has increased during the last 20 years. Applications for traditional and new practical battery systems are increasing, and the market for lithium-ion batteries and nickel-metal hydride batteries has grown remarkably. This chapter deals with consumer-type batteries, which have developed relatively recently. 

Batteries using an alkaline solution for electrolyte are commonly called alkaline batteries. They are high-power owing to the high conductivity of the alkaline solution. Alkaline batteries include primary batteries, typical of which are alkaline-manganese batteries, and secondary batteries, typical of which are nickel-cadmium and nickel-metal hydride batteries. These batteries are widely used. 

Nickel-metal hydride batteries contain a nickel electrode similar to that used in nickel-cadmium batteries as the positive... 

The nickel-metal hydride battery comes in two shapes cylindrical and prismatic. The internal structure of the cylindrical battery is shown in Fig. 18. It consists of positive and negative electrode sheets wrapped within the battery, with... 

Figure 20 shows the charge-discharge characteristics of the AA-size nickel-metal hydride battery in comparison with the nickel-cadmium battery produced by Sanyo Electric. Its capacity density is 1.5 to 1.8 higher than that of nickel-cadmium batteries. 

The discharge voltage of nickel-metal hydride batteries is almost the same as that of nickel-cadmium batteries. 

The outstanding characteristics of the nickel-metal hydride battery are as follows ... 

Since nickel-metal hydride batteries were commercialized in 1990, they have become increasingly popular as a power source for computers, cellular phones, electric shavers, and other products. 

Figure 25 shows nickel-metal hydrides batteries that have been improved by using the technique mentioned above. 

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