Association of European Automotive and Industrial Battery Manufacturers

Rechargeable alkaline batteries employ a nickel hydroxide based cathode, with either a metallic anode (Nickel-Cadmium (Ni/Cd), Nickel-Iron (Ni/Fe), Nickel-Zinc (Ni/Zn) or a hydrogen storing anode (Nickel/H2, Nickel-Metal Hydride (Ni/MeH)). Due to technical limitations on maintenance and long term cycling performance, Ni/Fe and Ni/Zn batteries cannot be used for automotive or stationary applications. Ni/MeH is technically superior to Ni/Cd in a number of technical aspects and it can be used in many applications.

Both Nickel/Hydrogen (Ni/H) and Ni/MeH batteries are, in principle, the same battery system, utilising nickel hydroxide (NiOOH) as positive and hydrogen (H2) as negative electrode materials. In Ni/MeH batteries a hydrogen storage alloy is used. Both systems have an excellent cycle life.

Nickel based batteries are used for standby as well as other applications, including Electric Vehicles (EV), Hybrid Electric Vehicles (HEV) and for starting aircraft. They are available with pocket-plate or sintered electrodes in steel or plastic containers. A full range of applications is served and nickel based batteries are especially suited to electrically or mechanically arduous applications.

Nickel based batteries have a positive electrode of nickel hydroxide and a negative electrode of cadmium. On discharge the nickel hydroxide is reduced to a different form of nickel hydroxide with a lower oxidation state and the cadmium is oxidised to cadmium hydroxide. The reverse reactions take place on recharge. The electrolyte is a potassium hydroxide solution. The construction of the battery differs for particular applications but there are two basic types; either a pocket-plate type or types using a sintered or bonded electrode structure. For pocket-plate types, a perforated nickel-plated steel pocket is used to contain the active material. For sintered or bonded types, a porous partially sintered nickel substrate may be used but various plastic bonded structures and fibrous constructions are also offered. The pocket-plate construction is highly reliable and offers moderate performance but the other types offer higher levels of electrical performance. Nickel based batteries may also be constructed in a fully sealed form similar to VRLA batteries. 
Nickel based batteries offer good resistance to electrical use as they can be left in a discharged condition for long periods without permanent damage and also offers good performance in higher ambient temperatures.