Nickel Cadmium Cell Technology

History

Invented in Sweden by Waldemar Junger in 1899, the first commercially available NiCd batteries were introduced in the early 1900s. This chemistry uses Nickel Oxide Hydroxide as the cathode and Cadmium as the anode. The resulting cell voltage from this chemistry is 1.2 Volts.

As NiCd is a relatively old technology, newer chemistries have made it effectively obsolete in all but some low cost industrial applictions (such as emergency lighting) and those for which it still has exemption from market ban (e.g. cordless power tools).

Advantages

• NiCd is relatively inexpensive when compared to newer chemistries
• NiCd has good specific energy compared to technologies such as lead-acid
• Good pulse power performance made it the initial chemistry of choice for powertools
• Stable chemistry can be abused (overcharged or over-discharged) without immediate permanent damage as is often the case with other advanced chemistries.
• NiCd cells are relatively easy to manufacture and are available in a wide array of small form factors
• Higher cycle life performance
   

Disadvantages

• Cadmium is a toxic, heavy metal that is known to cause diseases and thus must be recycled rather than discarded
• NiCd has been banned from sale in all but a select few applications in the EU
• Low energy density compared with newer technologies such as NiCd and LiIon
• High self-discharge rate
• NiCd can exhibit voltage depletion or voltage depression if repeatedly cycled at intermediate state-of-charge 
   

Attribute Chart

The Market

NiCd technology is ideal when low cost is critical or when small volume or low weight are not important. The number of new battery designs using NiCd is now very few and it is not recommended for modern portable electronics applications. Accutronics does not recommend this technology for new designs but does support a number of legacy products for demading industrial applications where NiCd remains a viable choice.

Accutronics has helped a number of customers with NiCd powered applications to 'upgrade' to Nickel Metal Hydride technology. This can sometimes be done without modification to the charger or application but this depends on cell availability and the charging strategy that has been employed. If you have an existing NiCd powered application and you wish to talk to someone about upgrading or replacing this with a higher technology then please contact us to discuss.