Nickel-Cadmium Battery

What Does Nickel-Cadmium Battery Mean?

A nickel-cadmium battery (NiCd or NiCad) is a rechargeable battery used for portable computers, drills, camcorders and other small battery-operated devices requiring an even power discharge. NiCds use electrodes made of nickel oxide hydroxide, metallic cadmium and an alkaline electrolyte of potassium hydroxide.


The NiCd battery was invented by Waldemar Junger and patented in 1899.

Techopedia Explains Nickel-Cadmium Battery

Two or more NiCd battery cells combine to form a battery pack. Because they are often sized like primary cells (non-rechargeable batteries), NiCds may have lower terminal voltage and less ampere-hour capacity. However, NiCds provide a nearly constant terminal voltage during discharge, unlike primary cells, which results in nearly undetectable low charges. During discharge, NiCd batteries transform chemical energy into electric energy. During recharge, NiCds retransform electric energy into chemical energy.

NiCd battery advantages are as follows:

  • Tolerates deep discharges over long periods
  • More charge/discharge cycles than other rechargeable batteries for longer battery life
  • Higher energy density, lighter and more compact than lead-acid batteries. NiCd is preferable when size and weight are key factors, such as in airplanes.
  • Lower self-discharge rate than nickel-metal hydride (NiMH) batteries (20 percent per month versus 30 percent per month)

NiCd batteries are extremely toxic. Additionally, nickel and cadmium are expensive metals.

Unlike lead-acid batteries, NiCd batteries heat excessively, go into thermal runaway mode and self-destruct if charged with a dynamo – even in over-current cutout systems. However, NiCd battery packs are usually equipped with an interior thermal charger cutoff, which is signaled if a battery heats and/or reaches maximum voltage.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.