Nickel Cadmium Battery

Operation

The cathode and anode of this battery are both constructed of nickel oxide, while the electrolyte is a solution of potassium hydroxide. The Nickel Cadmium Battery is reusable since it is rechargeable. A nickel-cadmium battery discharges chemical energy into electrical energy, which is subsequently converted back to chemical energy upon recharging. Ni(OH)2 and Cd(OH)2 are the two hydroxides that are present in a fully depleted NiCd battery's cathode and anode, respectively. The cathode's chemical makeup changes during charging, and nickel hydroxide becomes nickel oxyhydroxide [NiOOH]. In the anode, cadmium hydroxide is changed into cadmium. According to the formula below [26], the process is reversed when the battery empties.

Depth of Discharge

Nickel-cadmium batteries may be completely discharged without causing damages. Because nickel-cadmium batteries are less likely to overcharge, less charging is necessary. A maximum DOD of 90% for a nickel-cadmium battery in a PV system is therefore often specified. Because of these batteries' capacity for complete discharge, tolerance for overcharging, and charging schedules, the battery regulator may occasionally be skipped. Lead-acid batteries are more susceptible to freezing at low charge levels than nickel-cadmium batteries are because the composition of the electrolyte does not change when charging or discharging. With temperatures as low as -50 C, nickel-cadmium batteries are hence less suited to cold climates. Furthermore, high-temperature activities do not shorten the lifetime of nickel-cadmium batteries like they do with lead-acid batteries.

Lifetime

In nickel-cadmium batteries, oxidation and reduction activities take place on the positive and negative electrodes. The material does not penetrate the electrolyte and then re-plate to the electrodes, as with lead-acid batteries. This indicates that a process like lead-acid battery sulfation does not take place and that the active material does not shed from the plates. Due to these processes, lead-acid batteries have a shorter lifespan than nickel-cadmium batteries. Additionally, the electrolyte in nickel-cadmium batteries lasts longer than lead-acid batteries because it is less corrosive to battery components.

Battery Efficiency and Maintenance

In addition to having lower overall efficiencies, which range from 60% to 75%, nickel-cadmium batteries also have lower coloumbic efficiencies, which range from 75% to 85%. Lead-acid batteries are frequently less costly than nickel-cadmium batteries. However, some of this expense could be offset by being able to fully discharge, which avoids the need to oversize the battery and the potential need for the regulator. So long as nickel-cadmium batteries are virtually completely discharged each night, they can be used in non-critical applications. On the other hand, there is no electricity if a cloudy day happens to fall during a charging cycle. Nickel-cadmium batteries may only be used for non-critical loads as a result. Since they produce fewer corrosive elements and have less gassing, nickel-cadmium batteries require less regular maintenance.