Nickel–hydrogen battery

A nickel–hydrogen battery (NiH₂ or Ni–H₂) is a rechargeable electrochemical power source based on nickel and hydrogen.^[1] It differs from a nickel–metal hydride (NIMH) battery by the use of hydrogen in a pressurized cell at up to 1200 psi (82.7 bar) pressure.^[2]

The cathode is made up of a dry sintered^[3] porous nickel plaque, which contains nickel hydroxide, the negative hydrogen electrode utilises a teflon-bonded platinum black catalyst, the separator is knit zirconia cloth ^[4][5]

NiH₂ cells using 26% potassium hydroxide (KOH) as an electrolyte have shown a service life of 15 years or more at 80% depth of discharge (DOD)^[6] The energy density is 75 Wh/kg, 60 Wh/dm^3[7] specific power 220 W/kg.^[8] The open-circuit voltage is 1.55 V, discharge voltage 1.25 V,^[9] and the voltage under load 1.5 V.

While the energy density is only around one third as that of a lithium battery, the specific property of the nickel–hydrogen battery is its long life: the cells handle more than 20,000 charge cycles^[10] on 85% efficiency.

NiH₂ rechargeable batteries possess good electrical properties which make them attractive for the energy storage of electrical energy in satellites^[11] and space probes. For example, the ISS,^[12] Mars Odyssey^[13] and the Mars Global Surveyor^[14] are equipped with nickel–hydrogen batteries. The Hubble Space Telescope, 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 of any NiH₂ battery in low earth orbit.^[15]

History

The development of the nickel hydrogen battery started in 1970 at Comsat^[16] and was used for the first time in 1977 aboard the U.S. Navy's Navigation technology satellite-2 (NTS-2).^[17]

Designs

Individual pressure vessel

The individual pressure vessel (IPV) design consists of a single unit of NiH₂ cells in a pressure vessel. ^[18]

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 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 electrodes, positive-to-negative back-to-back stacked in a SPV. ^[19]

Dependent pressure vessel

The dependent pressure vessel (DPV) cell design offers higher specific energy and reduced cost.^[20]

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.^[21]

• Schematics
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See also

• List of battery types
• Power-to-weight ratio
• Pressure vessel
• Timeline of hydrogen technologies

References

1. ^ A simplified physics-based model for nickel hydrogen battery
2. ^ Nickel-hydrogen spacecraft battery handling and storage practice
3. ^ Performance comparison between NiH₂ dry sinter and slurry electrode cells
4. ^ [1].
5. ^ Nickel-Hydrogen Batteries
6. ^ Potassium hydroxide electrolyte for long-term mickel-hydrogen geosynchronous missions
7. ^ Spacecraft Power Systems Pag.9
8. ^ NASA/CR—2001-210563/PART2 -Pag.10
9. ^ Optimization of spacecraft electrical power subsystems -Pag.40
10. ^ Five-year update: nickel hydrogen industry survey
11. ^ Ni-H₂ Cell Characterization for INTELSAT Programs
12. ^ Validation of International Space Station electrical performance model viaon-orbit telemetry
13. ^ A lightweight high reliability single battery power system for interplanetary spacecraft
14. ^ Mars Global Surveyor
15. ^ NiH₂ reliability impact upon Hubble Space Telescope battery replacement
16. ^ Nickel-hydrogen battery technology—development and status
17. ^ NTS-2 Nickel-Hydrogen Battery Performance 31
18. ^ Nickel hydrogen batteries-an overview
19. ^ Development of a large scale bipolar NiH₂ battery.
20. ^ 1995–dependent pressure vessel (DPV)
21. ^ Common/dependent-pressure-vessel nickel-hydrogen Batteries

External links

• Overview of the design, development, and application of nickel-hydrogen batteries
• Details of the NiH₂-battery
• Implantable nickel hydrogen batteries for bio-power applications
• NASA handbook for nickel-hydrogen batteries
• A nickel/hydrogen battery for terrestrial PV systems
• A microfabricated nickel-hydrogen battery using thick film printing techniques

External reading

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

ISBN 1-884989-20-9