Publisher Summary This chapter provides an overview of nickel batteries. Numerous types of nickel batteries are discussed, such as nickel-cadmium secondary batteries, nickel-hydrogen batteries, and sodium-nickel chloride secondary batteries. Specification of the types of batteries is provided according to its manufacturer. SAFT (Socirt6 des Accumulateurs Fixes et de Traction), a major manufacturer of alkaline batteries, produce a full range of sealed nickel-cadmium batteries, including open type (GPX) and semi-open type (VOK-VOKH-VHP), both of which are higher capacity types. SAFT also produce sealed cells and batteries and button cells. Varta supply a non-sealed double cell (DTN) for portable lamps. This battery is available in a capacity range 4.5-11 A h. It has a light weight, even voltage level, good capacity, long service life, lack of maintenance and low self-discharge rate. Yardney USA pioneered the development of nickel-zinc battery and are still the main suppliers. The original application was electric traction, and a number of road vehicles are now operating powered by Yardney experimental batteries.