If you are looking for a reliable and durable battery for your device, you may have heard of nickel-cadmium batteries (Ni-Cd batteries for short). The world's first one was invented by Waldemar Jungner in Sweden in 1899, and it was not commercialized until 1960. In today's market, nickel-metal hydride batteries have gradually replaced nickel-cadmium batteries due to their large capacity and low price.
In this article, we will introduce you to the working principle, advantages and disadvantages of nickel-cadmium batteries and whether it is suitable for home energy storage applications.
What is a Nickel Cadmium Battery?
A nickel cadmium battery is a type of rechargeable battery that uses nickel oxide hydroxide and metallic cadmium as the positive and negative electrodes, respectively. The electrolyte is usually potassium hydroxide, a strong alkaline solution. The chemical reaction that occurs in a nickel cadmium battery is as follows:
The nickel cadmium battery was invented by Swedish engineer Waldemar Jungner in 1899, and improved by American inventor Thomas Edison in 1901. It was one of the first commercially available rechargeable batteries, and it has been widely used in various applications, such as portable electronics, power tools, medical equipment, military devices, and aerospace systems.
Structural Characteristics of Nickel-cadmium Batteries
Nickel-cadmium (NiCd) batteries have evolved significantly since their invention. In the early stages, the first key development occurred in 1932, when active materials were deposited inside a porous nickel electrode. By the 1940s, NiCd batteries in "pouch" form, encased in nickel-plated steel, began to emerge in the U.S.
However, it was the introduction of sintered plate NiCd batteries that brought major improvements. These plates, created using molten nickel powder under high pressure at low temperatures, had high porosity—around 80%—which allowed for better energy flow and reduced internal resistance. The positive and negative electrodes were formed by immersing nickel plates in their respective active materials, nickel and cadmium.
Sintered plates were thinner and offered a larger surface area than the pouch designs, resulting in higher efficiency and current output. From the 2000s onward, NiCd batteries adopted the jelly-roll configuration, in which the electrodes are rolled into a spiral shape. This modern structure remains the most common for consumer-grade NiCd batteries, balancing compactness, performance, and cost.
Advantages of NiCad Batteries
Voltage Stability During Discharge
Nickel-cadmium batteries have a stable voltage output of around 1.2 volts over most of the discharge cycle, a characteristic that means they maintain stable performance with only a slight voltage drop as they approach depletion. This means devices powered by NiCd batteries can run longer without significant performance degradation.
Excellent Cold Weather Performance
Nickel-cadmium batteries are known for their excellent performance in cold temperatures. Nickel-cadmium batteries are capable of operating effectively at temperatures as low as -20°C (-4°F), whereas many other battery types, such as lead-acid batteries, experience significant performance degradation under the same conditions.
High Discharge Rate
NiCd batteries are capable of delivering high discharge rates, meaning they can discharge their full rated capacity in one hour or less. NiCd batteries can discharge approximately 80-100% of their rated capacity in less than 60 minutes.
Disadvantages of NiCad Batteries
Higher Cost
NiCad batteries cost significantly more per watt-hour than lead-acid batteries.
High Self-Discharge Rate
NiCad batteries lose their charge relatively quickly when not in use. This phenomenon, called self-discharge, can cause them to lose up to 10% of their charge per month, much more than lithium-ion batteries, which only lose about 2-3% per month.
Memory Effect
If a battery is repeatedly charged before being fully discharged, it "remembers" the lower capacity, which causes performance to degrade over time. The memory effect can cause a 20-30% reduction in capacity after a few partial charges.
Cadmium Issues
NiCad batteries contain cadmium, a toxic substance that is harmful to both human health and the environment. In the EU, the use of NiCad batteries is limited to specific uses, such as medical devices, due to concerns about cadmium contamination.
Nickel Cadmium Battery Uses
Nickel-cadmium batteries are no longer used much in consumer electronics, but they are still effective in certain applications because of their high discharge rate, durability, and ability to operate in harsh conditions. As technology has improved, newer battery technologies such as lithium-ion and nickel metal hydride (NiMH) have gradually replaced nickel-cadmium batteries in many applications.
Power Tools
- Cordless Drills, Sawzalls, and Other Tools: NiCd batteries are still commonly used in older cordless power tools due to their ability to provide a high power output for short bursts, as well as their durability in tough environments.
- Heavy-Duty Usage: They are preferred in power tools that require frequent charging and discharging cycles, as they can withstand these conditions better than some other types of batteries.
Medical Devices
- Portable Medical Equipment: NiCd batteries are used in certain medical devices, such as defibrillators and portable oxygen concentrators. These devices require reliable power over extended periods, and NiCd's ability to operate in a range of temperatures makes them a good option.
- Wheelchairs: Some older models of electric wheelchairs or mobility scooters still use NiCd batteries, as they are durable and can withstand frequent use.
Aerospace and Military Applications
- Satellite Power Systems: NiCd batteries have been used in space applications like satellites, due to their ability to handle extreme temperatures and their reliability in long-duration cycles.
- Military Radios and Equipment: The military has long used NiCd batteries in communication equipment, because of their ability to perform under harsh conditions and their ruggedness.
Toys and Consumer Electronics
- Rechargeable Toys: Some older rechargeable toys, especially larger battery-operated toys, still use NiCd batteries for their ability to deliver high power.
- Portable Electronic Devices: While they have been largely replaced by lithium-ion, NiCd batteries were once commonly used in portable consumer electronics like portable radios, walkie-talkies, and handheld gaming devices.
Uninterruptible Power Supplies (UPS)
- UPS Systems for Computers and Servers: NiCd batteries have been widely used in uninterruptible power supplies, as they can provide reliable backup power when the main electricity supply fails.
- Data Centers: Older UPS systems in data centers and telecom equipment still use NiCd batteries for backup power.
Hybrid and Electric Vehicles (Older Models)
- Hybrid Vehicle Batteries: NiCd was once used in hybrid electric vehicles (HEVs) as the main power source, although it has been largely replaced by more energy-efficient lithium-ion batteries in modern vehicles. Some older hybrid models, like the first-generation Toyota Prius, used NiCd battery packs.
Battery-Powered Garden Equipment
- Cordless Lawn Mowers, Trimmers, and Leaf Blowers: Some garden tools still use NiCd batteries for their power and performance, though newer models are increasingly switching to lithium-ion batteries for longer run time and lighter weight.
RC (Remote Control) Models
- RC Cars, Boats, and Helicopters: NiCd batteries have been widely used in remote control hobby models for years. They provide a good balance of power output and charging cycles, though lithium-based options are becoming more popular due to their higher energy density.
Photographic Equipment
- Camera Flash Units: Older camera flash units sometimes used NiCd batteries, as they could provide the quick bursts of energy needed for flash photography.
- Battery Packs for Film Cameras: Certain older film cameras and their battery packs utilized NiCd batteries.
Are Nickel-cadmium Batteries Suitable For Home Energy Storage?
Nickel-cadmium batteries aren’t the best choice for home energy storage for a number of reasons.
They have low energy density, meaning they’re bulkier and less efficient than other options. They also suffer from the memory effect, which reduces their capacity over time if not fully discharged. NiCd batteries have a high self-discharge rate, meaning they lose charge even when not in use.
While they may be cheaper upfront, their shorter lifespan makes them more expensive in the long run. Lithium-ion and lead-acid batteries are far better suited for modern home energy storage due to their higher efficiency, longer lifespans, and better overall performance.
If you are looking for a device suitable for home energy storage, Shielden's home energy storage is one of your best choices.
