Waldemer Junger invented the Nickel-cadmium batteries in 1899. Nickel-cadmium battery is used for drills, portable computers, camcorders, etc. Things related to Nicd battery charging will be discussed in this article.
What are NiCad Batteries?
A battery pack is made up of two or more NiCd battery cells. NiCds may have a lower terminal voltage and a lower ampere-hour capacity. This is because they are sized like primary cells (non-rechargeable batteries).
During discharge and recharge
• NiCd batteries convert chemical energy into electric energy during ‘discharge’.
• NiCds convert electrical energy back into chemical energy during ‘recharge’.
Size affects a Ni-Cd battery’s maximum discharge rate. Typical AA-size cells have a maximum discharge rate of 1.8 amperes. For a D-size battery, this discharge rate can go up to 3.5 amperes.
NiCd’s batteries Uniqueness:
There are several significant ways in which Nickel-cadmium batteries differ from standard alkaline or lead-acid batteries. For instance:
• Nickel-Cadmium batteries have a lower and steady cell voltage. It is able to maintain it till it is depleted. Because of this, NiCad batteries can operate at maximum capacity all the way through their discharge cycle.
• Longer battery life thanks to more charge/discharge cycles than conventional rechargeable batteries.
• The self-discharge rate is lower than that of Nickel-metal hydride (NiMH) batteries. The approximate discharge rate of Nickel-cadmium batteries is 20% per month whereas Nickel-metal hydride (NiMH) batteries are 30%.
• It also tolerates prolonged deep discharges.
Cell Voltage of Nickel-cadmium batteries
The nominal cell potential of Ni-Cd batteries is 1.2 volts (V). A Ni-Cd terminal’s cell voltage fluctuates little when it discharges, unlike alkaline and zinc-carbon primary cells.
Also, Nickel-cadmium batteries aren’t proper to use as a replacement for zinc-carbon primary cells in all applications. The reason for this is that the average cell voltage of Ni-Cd is only 1.2 volts. This cell voltage is less than the alkaline and zin-carbon cell’s 1.5V.
Storing NiCd Batteries
Nickel-Cadmium batteries should be stored in a cool, dry place. Before storing, the battery needs to be discharged. If the full discharging is not done, the battery life can be shortened.
Charge voltage indicates after a battery is charged, how much voltage it will have. In other words, the charge voltage is that voltage that is available at a specific time when charging.
Nickel Battery Charging Basics
Nickel Cadmium, or NiCd, batteries must be charged appropriately in order to function. If nickel-cadmium batteries aren’t charged properly, their survival will be limited. Nickel-cadmium batteries require a steady current source to be charged.
In order to reduce the amount of degradation during storage, Nickel-cadmium battery production companies don’t fully form their batteries. So, it’s essential to slowly charge new batteries before using them.
Usually, this initial charging takes 15 to 24 hours. The charging also depends on the particular cell. It is also advised to check the producing companies’ datasheet to check the charging requirements.
Cells may be self-discharged at different rates in the route. That’s why it is important to provide the best initial charge so that all cells have the same charge. The same level of charge also primes each cell appropriately.
Also, a Li-on charger can be used to charge Nickel-cadmium batteries. However, a Nickel-cadmium charger can’t be used to charge Li-on batteries.
Faster Charging of Nickel-cadmium batteries
Charge efficiency is increased via fast charging. 0.4 C5 A for 2.5 hours followed by 0.2 C5 A for 2.5 hours is advised for rapid charging. It’s always in the best interest of Nickel-Cadmium batteries to use a good charger.
Using a voltage or temperature monitor charge speeds for NiCad batteries can reach 1C. Alternatively, 100% of the battery’s amp-hour capacity for 1.5 hours.
Overcharging Nickel-cadmium batteries
It is possible to overcharge the Nickel-cadmium batteries. However, to compensate for self-discharge, the Nickel-cadmium batteries receive a 0.05-0.1C trickle charge.
The lowest feasible trickle charge current is the goal of charger designers in order to minimize potential overcharging. Despite this, it is preferable to not charge nickel-based batteries for longer than a few days.
The reason for not using Nickel-cadmium batteries in mobile phones
There are several disadvantages to using Nickel-Cadmium batteries in mobile phones. For instance:
• In comparison to newer systems, the NiCad battery has low specific energy.
• Nicad battery’s energy density is lower, in terms of weight and volume.
• Cadmium is also a poisonous metal. So, it is not acceptable for disposal in landfills.
• NiCad battery also has a high self-discharge.
Full-charge Detection by Temperature or Voltage Signature
Full-charge Detection by Temperature of Nickel-Cadmium Batteries
Temperature can play a role in the full charge detection in Nickel-Cadmium batteries. 50℃ or 122°F temperature of the battery indicates its full charge. Battery producers use this temperature to stop overcharging of batteries.
To remain cautious, it is advised not to charge the battery above 45°C or 113°F. But a little overshoot is okay when the “ready indicator shows and temperature declines rapidly.
Full-charge Detection by Voltage Signature of Nickel-Cadmium Batteries
When a specific voltage signature appears, advanced chargers stop charging. This offers a nickel-based battery full-charge detection that is more accurate than temperature-based techniques.
After a Nicd battery is properly charged, there is a tiny drop in terminal voltage. Microprocessor-based chargers can track the voltage and identify the point at which the battery is fully charged. When the battery is fully charged, the charging process is stopped.
Cadmium Electrode and Nickel Cadmium Battery
The cadmium electrode is negative in the Nickel-cadmium battery system. The average cell voltage in NiCad batteries is 1.2 V during charge. The highest voltage is 1.3 V during charge in Nickel-Cadmium batteries.
Let us know if you have any questions about Nicd battery charging.