Electric vehicle batteries nickel hydrogen

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. 

Nickel metal hydride (Ni-MH) batteries have application in hybrid electric vehicles, portable electronic devices such as cameras, shavers, toothbrushes, etc. They offer a higher energy option than Ni-Cd batteries with the hydrogenabsorbing metal hydride alloy (MH) replacing the cadmium electrode in Ni-Cd cell construction. Like Ni-Cd, the Ni-MH also shows the memory effect on repetitive cycle regimes. The nickel metal hydride battery was introduced commercially in 1989. The technology is based on the development of rare earth alloys with nickel that have the ability to reversibly absorb and desorb hydrogen. The... 

Nickel/metal hydride (Ni/MH) battery is a secondary battery using hydrogen storage alloy for the negative electrode, Ni(OH)2 for the positive electrode, and alkaline solution for the electrolyte. Polypropylene nonwoven fabric is usually selected for the separator. The theoretical voltage is about 1.32 V, and the operating voltage is about 1.2 V which is almost the same as that of Ni/Cd battery [1]. The Ni/MH battery has been put to practical use for portable electric equipments in 1990 and for HEV (hybrid electric vehicle) in 1997 [2, 3]. 

As with the primary battery systems, significant performance improvements have been made with the older secondary battery systems, and a number of newer types, such as the silver-zinc, the nickel-zinc, nickel-hydrogen, and lithium ion batteries, and the high-temperature system, have been introduced into commercial use or are under advanced development. Much of the development work on new systems has been supported by the need for high-performance batteries for portable consumer electronic applications and electric vehicles. Figure 22.1 illustrates the advances achieved in and the projections of the performance of rechargeable batteries for portable applications. 

Other metal couples that are considered at present to be of great potential are the nickel-hydrogen and nickel-zinc systems. These map be batteries of the future in applications such as utilities load levelling and electric vehicles the latter type is, in fact, now in commercial production. 

Yuasa, Japan have been developing prototype nickel-hydrogen batteries for electric vehicle applications. They have claimed 200 maintenance free cycles at 100% depth of discharge. 

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