The maximum electromotive force offered by a Ni–Cd cell is 1.3 V. A Ni–Cd battery has a terminal voltage during discharge of around 1.2 volts which decreases little until nearly the end of discharge. Wet-cell nickel–cadmium batteries were invented in 1899. The abbreviation Ni–Cd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd): the abbreviation NiCad is a registered trademark of SAFT Corporation, although this brand name is commonly used to describe all Ni–Cd batteries. The nickel–cadmium battery ( Ni–Cd battery or NiCad battery) is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. From top to bottom: 'Gumstick', AA, and AAA Ni–Cd batteries
