Maximizing the Cycle Life of Nickel Cadmium Batteries: Effective Maintenance Tips


Maximizing the Cycle Life of Nickel Cadmium Batteries: Effective Maintenance Tips
Introduction
Nickel Cadmium (Ni-Cd) batteries have long been
used in various applications due to their durability and reliable ability to
deliver consistent reliable power. However, like all batteries, they require preventive
maintenance to ensure designed life. In this blog post, we will explore
effective strategies to keep your Ni-Cd batteries healthy and optimise their
lifespan.
Use the Correct Charger
The charging process plays a vital role in
maintaining the health of Ni-Cd batteries. Invest in a quality charger
specifically designed for Ni-Cd batteries. Such chargers provide a controlled
charging voltages (Boost & Float) and current and terminate the charging
process automatically when the battery bank is fully charged.
Charging
Battery can be charged by constant current and constant voltage methods.
In normal operation, constant voltage method is applied.
While during the commissioning stage, constant current charging method
is applied.
Special attention needs to provided for batteries connected as parallel strings
. As current carried by each string would depend on the resistance of each
string.
During regular usage, the charging method and parameters are to be
determined by system requirements. A lower charging current can be applied for
a proportionally longer time. Normally lower charging currents demonstrate
better charge acceptability for batteries, but on the other hand, charging
would need longer time.
Consistent Discharge and Usage
Ni-Cd batteries perform best when they are
regularly discharged and used. Follow these practices to maintain a healthy
battery:
a. Cyclic Operation: Ni-Cd batteries benefit from regular full discharges followed by
full recharges. This process ensures the battery operates at its full capacity.
However, we need to consider the Depth of Discharge (DOD) and the number of
cycles to determine the life cycle of the batteries. Typical such application
is Solar application where batteries are charged during say time and discharged
during night.
b Float application: This is a typical battery back up application, where load is
supplied by charger and batteries are used only when power / charger fails.
Regularly discharge
your Ni-Cd battery to prevent it from sitting idle for extended periods. It is
observed that during such float applications, the batteries may demonstrate
reduced capacity.
Temperature Considerations
Operating Temperature has a impact on the cycle
life of Ni-Cd batteries. Follow these temperature-related guidelines to ensure
the health of your batteries.
Optimal Storage Temperature
A filled and charged battery can
be stored for a maximum period of six months, from the date of last charge.
Filled and discharged batteries can be stored for one year. Do not store
other material on top of the battery. Store the batteries in an enclosed
room (10‐30˚C) and having sufficient
ventilation. Cover the battery with a sheet of plastic or similar
protective cover to keep out water and shield against direct sunlight.
After removing from storage, the battery should be
deep discharged to an average cell voltage of 1.0 V by discharging at 0.2
C5 Amps, followed by deep discharge at 0.1 C5 Amps until all cell voltages
fall below 0.6 Volts. Minimum 12 hours of time gap shall be given before
starting to charge the cells.
However, a dry and discharged battery can be stored for
prolonged periods.
Operating Temperature:
The battery will give the best performance and maximum service life when
working at a
temperature between 10 and 30˚C. Freezing will not cause damage
to the battery. With
adequate electrolyte specific gravity adjusted; the battery will perform
properly up to – 40˚C.
Performance of nickel cadmium battery would be much better at elevated temperatures
as compared to lead acid type batteries. All internal cell parts are nickel
plated and can sustain the high temperatures up to 50˚C. The result of
sustained high temperature would be quicker electro‐chemical reaction (high float current, poor internal
gas recombination), leading to more water loss, necessitating water topping up,
to maintain electrolyte level. If timely topping up of water is carried out,
battery will continue to meet the requirements. However, if battery is operated
continuously at higher temperatures, the overall life of battery would get
reduced, when compared to it’s operation between recommended 10 to 30˚C.
Regular Maintenance Checks
Performing routine maintenance checks can help
identify potential issues before they escalate. Consider the following steps:
a. Inspect for Corrosion: Check the battery terminals regularly for any signs of corrosion.
If you notice corrosion, gently clean the terminals using a soft cloth and a
mild cleaning agent.
b. Tighten Connections: Ensure that all connections between the battery and the device or
charger are secure. Loose connections can lead to poor performance or damage to
the battery.
c. Monitor Capacity: Periodically test the capacity of your Ni-Cd batteries using a
battery analyser or suitable testing equipment. This can help you identify any
decrease in capacity and take appropriate action.
d. Charger Discharge Test: The Charge/ discharge test of the Batteries using a load bank once
in an year will help support to keep the batteries in good health and long
life. Ensure to get the service from an experienced firm using high quality
test equipment to obtain better service and maintenance.
Electrolyte Replacement
In most stationery battery applications, the
electrolyte will retain its effectiveness for the life of the battery. However,
under special battery service conditions, such, as high temperature and / or
frequent cycling, potassium carbonate build up in the electrolyte may reach a
level that will influence the battery performance. If the potassium carbonate
reaches a level of 75 grams/ litre, is said to be carbonized, and the battery
performance can be restored to a great extent by replacing the electrolyte.
The type of electrolyte to be used for replacement
is given below.
CELL
TYPE |
ELECTROLYTE TYPE FOR
FIRST FILLING |
ELECTROLYTE TYPE FOR REPLACEMENT |
ELECTROLYTE TYPE FOR COMMISSIONING IF
SUPPLIED DRY |
Standard |
B‐22, Density 1.20 |
B‐5, Density 1.19 |
B‐22, Density 1.20 |
Special Application (Solar) |
B‐30, Density 1.28 |
B‐12, Density 1.25 |
B‐30, Density 1.28 |
a. Preparation of
Electrolyte
1000 cc Type B electrolyte
contains the following quantities of potassium hydroxide, lithium hydroxide and
DM/DI water.
ELECTROLYTE TYPE FOR REPLACEMENT |
POTASSIUM HYDROXIDE (88‐89%) |
LITHIUM HYDROXIDE (55%) |
DM/DI
WATER |
B‐5, Density 1.19 |
276
gms |
9
gms |
910
cc |
B‐12, Density 1.25 |
363
gms |
22
gms |
870
cc |
Use this data as proportions for
preparing the electrolyte for the battery in suitable batch
quantities depending on the size
of the vessels available for electrolyte preparation.
b. Discharge
Before emptying the electrolyte, discharge the battery to a voltage
corresponding to about 0.6 volt/cell with current not higher than of 0.2C5 rate.
The plates shall never be exposed to open atmosphere in charged condition.
c. Emptying
Open the vents and place the battery inverted to drain the cells. Let
the cells drain for about 5 minutes. Do not shake the cells. Beware of
electrolyte splashes. Do not rinse with water, as this may cause trouble in
obtaining correct electrolyte density after filling. Never let cells remain
empty if they are not entirely discharged as this can cause permanent damage. It
is not advisable to pour the used electrolyte into the sink. Follow norms for
chemical waste disposal, which are valid in your area.
d. Filling
Immediately after emptying, fill the cells
according to the instructions for the electrolyte filling.
e. Charge
Charge the battery according to the instructions for first charging. A
generous charge is important for the restoration of the battery performance.
f. Disposal of Used Batteries
Nickel cadmium batteries must not be discarded as harmless waste and
should be treated carefully in accordance with local and national regulations. Contact
HBL for disposal and recycling assistance. More than 99% of battery metals can
be recycled.
g. Spillage / Leakage of
Electrolyte
Please refer our MSDS which gives necessary
spillage management instructions.
Here are some additional maintenance tips for NiCd Batteries
- Inspect
the battery regularly for signs of damage. If the battery is leaking,
cracked, or swollen, it should be replaced immediately.
- Clean
the battery terminals with a wire brush and a mild solution of baking soda
and water. This will help to prevent corrosion and improve the
battery’s performance.
- Keep
the battery terminals free of dirt and debris. This will help to
prevent arcing and sparking, which can damage the battery.
By
following these maintenance tips, you can help to extend the lifespan of your
NiCd batteries and keep them in good working condition.
Conclusion
By following these maintenance tips one can
optimise the cycle life of your Nickel Cadmium batteries and ensure their
optimal performance. Remember to charge them properly, consistently discharge
and use them, consider temperature conditions, and perform regular maintenance
checks. By taking these simple steps, you can enjoy the full potential and
longevity of your Ni-Cd batteries in various applications.