Nickel–iron battery

Of the nickel-iron battery, even Edison battery is used with the nickel -cadmium storage battery, however, iron, instead of the toxic cadmium used.

When charging the nickel electrode becomes coated with a black oxide coating which disappears during unloading. After charging is between the electrodes, a voltage of typically about 1.3 volts measurable, ie slightly lower than the charging voltage of the NiCd system of 1.4 V.

Reaction / structure

On the iron-nickel battery following reactions take place:

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When unloading done the reverse reactions.

The accumulator is filled with 20 % potassium hydroxide solution. Older types used a glass jar as the cell body, the necessary air seal (protection against carbon dioxide ) was carried out by covering the electrolyte with a thin layer of oil. The second generation often used a welded sheet metal container, modern forms a plastic housing. The air seal is effected here by a screwed-in pressure relief valve. This as well as the screw terminals and the connecting lugs are often made of nickel-plated iron.

History

The nickel-iron battery ( NiFe battery) was developed almost simultaneously by the renowned American inventor Thomas Edison and Sweden Waldemar Jungner, of the nickel-iron battery a little later to the still widely used nickel - cadmium battery (NiCd battery ) further developed. The first patents for the NiFe battery were issued in 1901, reached the production stage, however, until 1908. A priority dispute years, even as far as the points arising from the NiFe battery NiCd battery (1909 ), followed.

The NiFe battery has been used for example in mining lamps and in different cars. There was, for example, the option to buy a Detroit Electric with NiFe batteries from Edison. Jay Leno has a Baker Electric, in which the nickel-iron batteries are still functional after nearly 100 years.

Other applications were the power of the V-2 rocket, and after the war the driving electric forklift. Partial NiFe batteries are still in physical laboratories and schools in use.

Due to the extremely long service life, these batteries are used mainly for UPS systems and rail vehicles.

Of the nickel-iron battery is considered to be electrically and mechanically resistant. In particular, damage caused by overcharging or deep discharge, as is known from other accumulators, be impossible in these cells. These properties have led to a certain comeback of Technology in the decentralized power supply: Some enthusiasts prefer this type of battery, for example, on a small wind power system, or a passive house independently to make the power supply. ( Source: see links )

Upcoming Renaissance by graphs

Researchers in the U.S. have developed an electrode of nickel hydroxide particles on graphs. As fits to the iron electrode was found and led to the rediscovery of the nickel-iron battery. Neither fast on -current, over - yet deep discharge damage.