Nickel hydrogen battery
Encyclopedia
A nickel–hydrogen battery (NiH2 or Ni–H2) is a rechargeable electrochemical power source based on nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

. It differs from a nickel–metal hydride (NIMH) battery by the use of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 in a pressurized cell
Electrochemical cell
An electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...

 at up to 1200 psi
Pounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...

 (82.7 bar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...

) pressure.

The cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

 is made up of a dry sintered porous nickel plaque, which contains nickel hydroxide, the negative hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...

 utilises a teflon-bonded platinum black
Platinum black
Platinum black is a fine powder of platinum with good catalytic properties. The name of platinum black is due to its black color....

 catalyst, the separator is knit zirconia cloth

NiH2 cells using 26% potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...

 (KOH) as an electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

 have shown a service life
Service life
A product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....

 of 15 years or more at 80% depth of discharge
Depth of discharge
Depth of discharge is an alternate method to indicate a battery's state of charge . The DOD is the inverse of SOC: as one increases, the other decreases. While the SOC units are percent points , the units for DOD can be Ah or percent points...

 (DOD)
The energy density
Energy density
Energy density is a term used for the amount of energy stored in a given system or region of space per unit volume. Often only the useful or extractable energy is quantified, which is to say that chemically inaccessible energy such as rest mass energy is ignored...

 is 75 Wh/kg, 60 Wh/dm3 specific power
Specific power
In physics and engineering, surface power density or sometimes simply specific power is power per unit area.-Applications:* The intensity of electromagnetic radiation can be expressed in W/m2...

 220 W/kg. The open-circuit voltage
Open-circuit voltage
Open-circuit voltage is the difference of electrical potential between two terminals of a device when there is no external load connected, i.e. the circuit is broken or open. Under these conditions there is no external electric current between the terminals, even though there may be current...

 is 1.55 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

, discharge voltage 1.25 V, and the voltage under load 1.5 V.

While the energy density is only around one third as that of a lithium battery
Lithium battery
Lithium batteries are disposable batteries that have lithium metal or lithium compounds as an anode. Depending on the design and chemical compounds used, lithium cells can produce voltages from 1.5 V to about 3.7 V, over twice the voltage of an ordinary zinc–carbon battery or alkaline battery...

, the specific property of the nickel–hydrogen battery is its long life: the cells handle more than 20,000 charge cycles on 85% efficiency.

NiH2 rechargeable batteries
Rechargeable battery
A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...

 possess good electrical properties which make them attractive for the energy storage
Energy storage
Energy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulator....

 of electrical energy in satellites and space probe
Space probe
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...

s. For example, the ISS
ISS
The ISS is the International Space Station.ISS may also refer to:* I See Stars, an American electronic rock band* ISS A/S, a Danish service company* Idea Star Singer, a Malayalam music reality show by Asianet TV...

, Mars Odyssey
2001 Mars Odyssey
2001 Mars Odyssey is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectrometers and electronic imagers to hunt for evidence of past or...

 and the Mars Global Surveyor
Mars Global Surveyor
The Mars Global Surveyor was a US spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 10-year absence. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2...

 are equipped with nickel–hydrogen batteries. The Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

, when its original batteries were changed in May 2009 more than 19 years after launch, led with the highest number of charge and discharge cycles
Charge cycle
A charge cycle is the process of charging a rechargeable battery and discharging it as required into a load. The term is typically used to specify a battery's expected life, as the number of charge cycles affects life more than the mere passage of time...

 of any NiH2 battery in low earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

.

History

The development of the nickel hydrogen battery started in 1970 at Comsat
COMSAT
The Communications Satellite Corporation is a global telecommunications company, based in the USA, and with branches in Brazil, Argentina, Colombia, Mexico, Peru, Venezuela and several other countries in the Americas. It is present also in Turkey...

 and was used for the first time in 1977 aboard the U.S. Navy's Navigation technology satellite-2 (NTS-2).

Individual pressure vessel

The individual pressure vessel (IPV) design consists of a single unit of NiH2 cells in a pressure vessel.

Common pressure vessel

The common pressure vessel (CPV) design consist of two NiH2 cell stacks in series in a common pressure vessel. The CPV provides a slightly higher
specific energy
Specific energy
Specific energy is defined as the energy per unit mass. Common metric units are J/kg. It is an intensive property. Contrast this with energy, which is an extensive property. There are two main types of specific energy: potential energy and specific kinetic energy. Others are the gray and sievert,...

 than the IPV.

Single pressure vessel

The single pressure vessel (SPV) design combines up to 22 cells in series in a single pressure
vessel.

Bipolar

The bipolar design is based on thick electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...

s, positive-to-negative back-to-back stacked in a SPV.

Dependent pressure vessel

The dependent pressure vessel (DPV) cell design offers higher specific energy and reduced cost.

Common/dependent pressure vessel

The common/dependent pressure vessel (C/DPV) is a hybrid of the common pressure vessel (CPV) and the dependent pressure vessel (DPV) with a high volumetric efficiency.

See also

  • List of battery types
  • Power-to-weight ratio
    Power-to-weight ratio
    Power-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...

  • Pressure vessel
    Pressure vessel
    A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...

  • Timeline of hydrogen technologies
    Timeline of hydrogen technologies
    Timeline of hydrogen technologies — A timeline of the history of hydrogen technology.-1600s:* 1625 - First description of hydrogen by Johann Baptista van Helmont...


External links


External reading

  • Albert H. Zimmerman (ed), Nickel-Hydrogen Batteries Principles and Practice, The Aerospace Press, El Segundo, California

ISBN 1-884989-20-9
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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