Difference between lead acid and nickel cadmium batteries

There are several types of batteries available, both online and in your nearby store, that suit various applications. While high-density capacitors and solid-state batteries (like lithium-ion) stand at the tip of the technology spear, there is time before they go mainstream. For now, you have two options for your power storing needs: the lead acid battery and the nickel cadmium battery.

Yet, these batteries differ significantly in their structure and property, making them suitable for separate applications. You need to understand the difference between lead and nickel cadmium batteries to help you do that. And lucky for you, this is just the detailed guide you need.

What Are Lead Acid Batteries?

Lead acid batteries represent a tried-and-tested trope that has been around since the 19th century—such batteries store charges in the form of water-soluble ions. The main component for the electrodes is, you guessed it, lead. Its anode comprises porous lead wafers, whereas the cathode is made from lead oxide. That’s because it is an inexpensive metal that can easily change its ionization state, allowing for a more convenient flow of electrons.

What Are Lead Acid Batteries?
What Are Lead Acid Batteries

 

The electrolyte used in the batteries is usually a hydrochloric acid solution in distilled water. It is a 60:80 ratio, which provides plenty of hydrogen and oxygen ions to balance the chemical stability. That is why you need to add distilled water to lead acid batteries after they degrade in performance.

You can find lead acid batteries reasonably priced at your nearest home depot or an electrical supply shop. Most vehicles and inverters are configured to use these batteries, and they can last you for more than three years without much maintenance.

What Are Nickel Cadmium Batteries?

Nickel-cadmium batteries are solid-state batteries. Hence they utilize solid electrolytes such as potassium hydroxide. It allows for more efficient storage of charges while removing the thermal runoff that comes with the vaporization of electrolytes. The cathode is made from nickelic hydroxide, and the anode comprises cadmium metal.

What Are Nickel Cadmium Batteries?
What Are Nickel Cadmium Batteries

In the discharging state, the cadmium reacts with the potassium hydroxide solution to form cadmium hydroxide and releases electrons over an external load. The cathode absorbs those electrons to convert the nickelic hydroxide to nickel hydroxide. The flow of these electrons causes the current to flow in the circuit.

Thanks to its solid-state design, Ni-Cd batteries can be made incredibly small. They can deliver consistent current supply for long hours without heating up or losing efficiency. Due to their sealed design, you can use them in a wide range of temperatures and any orientation at your convenience.

Difference Between Lead Acid and Nickel Cadmium Batteries

Now that you know the basics of lead acid and Ni-Cad batteries, it is time to dwell on the more minute differences. Here are the various fields for consideration.

Structure

All lead acid batteries follow the same structural design. The anode must be thick and porous to allow the electrolyte to flow through it while maintaining a sufficient potential difference. For the cathode, it must be applied in the form of plates that share the same acidic solution.

The volume of electrolyte determines the density of charges that can be stored, and you need good seals for the terminals to prevent it from evaporating from the battery. That’s why lead acid batteries are often quite bulky, even for low-voltage applications.

On the other hand, nickel cadmium batteries are more flexible with their structure. You can use the electrodes in the form of blocks, sheets, cylinders, or even buttons. Most button cells contain a nickel-cadmium core with a potassium hydroxide solution.

Voltage Density

When considering unit volume, nickel cadmium batteries have much better voltage density than lead acid batteries. However, getting your hands on a high-voltage Ni-Cd battery is challenging due to its high manufacturing costs, which forces you to make do with lead acid batteries.

Current Capacity

If you want a stable current supply, nickel cadmium batteries are the ideal choice. Unlike lead acid batteries, they don’t have heating issues or electrolyte loss even after multiple hours of use. Moreover, you can overcharge nickel cadmium batteries without the risk of fire hazards.

Lifespan

A typical lead acid battery can go through about 200 charging and recharging cycles, which makes them viable for 3 to 5 years, depending on how long you leave them idle. Nickel cadmium batteries can last much longer since they can withstand up to 5000 cycles before giving out.

Lifespan
Lifespan

Reliability

Lead acid batteries are prone to numerous problems, from electrode degradation to electrolyte loss. Even if you have a sealed battery case, you can’t use lead acid batteries in hot and humid environments.

Ni-Cad batteries are much more reliable. You can use them for temperatures ranging from -20°C (-4°F) to 45°C (113°F). They are also not affected by physical conditions like humidity and dust concentration. Still, they have a memory effect issue. That means if you repeatedly charge the battery from less than 100%, it will never go above that potential after some time, reducing its capacity permanently.

Maintenance

Lead acid batteries require straightforward yet crucial maintenance cycles. The electrolyte level and quality are both significant factors. You must check them regularly to keep the battery’s efficiency at optimal levels. Additionally, you may need to replace the electrodes if they have persistent sulfate deposits.

When it comes to truly “zero-maintenance,” Ni-Cd batteries certainly fit the description. You can use them for several years without worrying about deterioration or current loss.

Cost

Since lead and sulfuric acid are inexpensive to manufacture, you can get high-density lead acid batteries for a relatively low price. On the other hand, Ni-Cd batteries are only viable for low-voltage applications, as cadmium is a rare metal that is more complicated to refine.

Which Battery Is Best For You

The best battery suited for you depends on what you need it for. Therefore, depending on the situation, you may prefer a specific variant.

When To Use Lead Acid Batteries

Lead acid batteries can be your preferred choice if you require substantial voltage on a budget. Keep in mind that you have to store them in an isolated location, away from sunlight and moisture, to maintain efficiency. They also require regular voltage checks and maintenance.

When To Use Nickel Cadmium Batteries

It is best to use nickel cadmium batteries if you need a stable current supply in variable environmental conditions and can spare a few extra bucks for capacity. Just make sure to charge them to the full for every cycle and dispose of them in an eco-friendly way.

Conclusion

The difference between lead acid and cadmium batteries represents a chasm between conventional methods and advanced technology. While the latter has its apparent advantages, it can’t become accessible unless you reduce the costs. We hope this guide helped you learn the distinction clearly. If you have any questions, kindly share them in the comments below.

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