Nickel-cadmium Battery
The nickel-cadmium battery (Ni-Cd battery) is a type of secondary battery using nickel oxide hydroxide Ni(O)(OH) as a cathode and metallic cadmium as an anode. The abbreviation Ni-Cd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd).
The battery has low internal impedance resulting in high power capabilities but lower energy storage capacity compared to other battery systems. It has long cycle life and the capability of rapid recharge but may suffer from voltage depression or memory effect, meaning that the maximum charge voltage will decrease and hence the energy capacity if continuously discharged shallowly. The greatest disadvantage is the content of cadmium. Unfortunately, cadmium is extremely toxic; therefore, the Ni-Cd will not be an alternative for a modern battery system.
Nowadays, the applications of nickel-cadmium batteries are in small-size portable devices such as power tools, toys, emergency lighting, medical instrumentation, or industrial portable products. It is used in small-size products because their cost for low-power applications is inexpensive but three to four times more expensive than lead-acid batteries for the same capacity.
Advantages and Disadvantages of Nickel-cadmium Batteries
Advantages:
The main advantage of rechargeable cells is that they may be recharged after discharge. Therefore, rechargeable batteries are more environmentally friendly than primary batteries. Not only can they be used repeatedly, but they generate less waste over the long term. This is particularly true in the case of power-intensive devices, which consume batteries at an increased rate. Another very important advantage is a high C-rate. Rechargeable cells have better power output capabilities compared to primary cells and are used for high-power applications.
There are several specific advantages to Ni-Cd batteries.
- Delivers high current output.
- Relatively tolerant of overcharging.
- Withstands up to 500 charging cycles.
Disadvantages:
Battery price is one of the challenging factors in choosing the right rechargeable battery for your device or applications. It greatly affects the decision of the buyer. Rechargeable batteries have higher initial costs than their primary counterparts. Another important disadvantage is their self-discharge. In low-drain applications, the service life is more important, and the self-discharge characteristics of a rechargeable battery mean that they are less suitable for use as the primary energy source.
There are several specific disadvantages to Ni-Cd batteries.
- Cadmium is not environmentally friendly.
- Noticeable charging memory effect.
