Nickel–metal hydride battery

Nickel–metal hydride battery
Modern Ni–MH rechargeable cells
Specific energy0.22-0.43 MJ/kg (60–120 W·h/kg)
Energy density140–300 W·h/L
Specific power250–1,000 W/kg
Charge/discharge efficiency66%[1]–92%[2]
Self-discharge ratePer month:
  • 13.9–70.6% at room temperature
  • 36.4–97.8% at 45 °C (113 °F)
  • Low self-discharge: 0.08–2.9%[3]
Cycle durability180[4]–2000[5] cycles
Nominal cell voltage1.2 V

A nickel–metal hydride battery (NiMH or Ni–MH) is a type of rechargeable battery. The chemical reaction at the positive electrode is similar to that of the nickel–cadmium cell (NiCd), with both using nickel oxide hydroxide (NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy instead of cadmium. NiMH batteries can have two to three times the capacity of NiCd batteries of the same size, with significantly higher energy density, although only about half that of lithium-ion batteries.[6]

They are typically used as a substitute for similarly shaped non-rechargeable alkaline batteries, as they feature a slightly lower but generally compatible cell voltage and are less prone to leaking.[7][8]

  1. ^ "NiMH Battery Charging Basics". PowerStream.com.
  2. ^ "Energy efficiency and capacity retention of Ni–MH batteries for storage applications".
  3. ^ "Best rechargeable batteries (10+ charts, overviews and comparisons )". eneloop101.com. 14 February 2017. Retrieved 2019-02-09.
  4. ^ "Eneloop XX Vs Turnigy 2400 Cycle Testing". CandlePowerForums. 24 October 2014.
  5. ^ "Product Lineup". Panasonic.net. Archived from the original on 2014-02-03. Retrieved 2014-01-26.
  6. ^ "Lithium-Ion Battery". Clean Energy Institute, University of Washington. Retrieved 8 January 2021.
  7. ^ "What could cause Ni-MH rechargeable batteries to leak?". Panasonic Batteries. 30 October 2019. Retrieved 8 August 2021.
  8. ^ "Do NiMH Batteries Explode?". Do NiMH Batteries Explode?. 6 June 2020. Retrieved 3 September 2021.