Editing Nickel–cadmium battery (section)

== History ==
The first Ni–Cd battery was created by [[Waldemar Jungner]] of [[Sweden]] in 1899. At that time, the only direct competitor was the [[lead–acid battery]], which was less physically and chemically robust. With minor improvements to the first prototypes, energy density rapidly increased to about half of that of primary batteries, and significantly greater than lead–acid batteries. Jungner experimented with substituting iron for the cadmium in varying quantities, but found the iron formulations to be wanting. Jungner's work was largely unknown in the United States. Thomas Edison patented a nickel– or cobalt–cadmium battery in 1902,<ref>[http://patimg1.uspto.gov/.piw?Docid=0692507&idkey=NONE US Patent 0692507]</ref> and adapted the battery design when he introduced the nickel–iron battery to the US two years after Jungner had built one. In 1906, Jungner established a factory close to Oskarshamn, Sweden, to produce flooded design Ni–Cd batteries.

In 1932, active materials were deposited inside a porous nickel-plated electrode and fifteen years later work began on a sealed nickel–cadmium battery.
 
The first production in the [[United States]] began in 1946. Up to this point, the batteries were "pocket type," constructed of nickel-plated steel pockets containing [[nickel]] and [[cadmium]] active materials. Around the middle of the twentieth century, [[Sintering|sintered]]-plate Ni–Cd batteries became increasingly popular. Fusing nickel powder at a temperature well below its melting point using high pressures creates sintered plates. The plates thus formed are highly porous, about 80 percent by volume. Positive and negative plates are produced by soaking the nickel plates in nickel- and cadmium-active materials, respectively. Sintered plates are usually much thinner than the pocket type, resulting in greater surface area per volume and higher currents. In general, the greater amount of reactive material surface area in a battery, the lower its [[internal resistance]].

Since the 2000s, all consumer Ni–Cd batteries use the [[Jelly roll (battery)|jelly-roll]] configuration.{{Citation needed|date=July 2017}}