Invented in I899 by Waldemar Jungner of Sweden, their practical application was only made possible after 50 years, with the introduction of the sealed battery by Frenchman, Neumann.
The Ni-Cd batteries are used in a number of applications worldwide. They comprise of a positive electrode plate that uses nickel hydroxide as the main material, and a negative electrode plate that uses cadmium compound as the main active material.
There's two varieties of Ni-Cd batteries: sealed and vented. The smaller sealed variety is used in toys and other portable electronics. Specialty Ni-Cd batteries are used in wireless and cordless telephones, old motherboards, laptops cell phones and other applications. These batteries can supply high surge currents making them perfect for use in remote-controlled cars, boats, airplanes, camera flash units etc.
In comparison with other rechargeable batteries, Ni-Cd is beneficial in lots of ways. They are strong and cannot be damaged easily, having the ability to withstand deep discharges for longer periods. They likewise have more endurance to the charge and discharge cycles. These batteries are small and lightweight even in comparison with the lead-acid battery, making them a preferred choice in aircraft where weight and size are crucial factors.
However, there is one drawback, if you're able to call it that. Ni-Cd are recognized for their “memory effect.” Memory effect is when batteries “think” that they're fully charged even when they're not. If your battery is about 80% charged, it thinks it is 100% charged, and for this reason thinking, does not charge any further even when placed on the charger. The thing is that when gadgets with Ni-Cd batteries are used, they last for a shorter time because of being charged less. This problem mostly affects older batteries and not the fresh new ones. However, there's a solution to this memory effect – that of performing a “full recharge cycle,” which would be to let the gadget discharge completely before recharging it again. For example, recharge only when your cell phone starts beeping.
Now that the memory effect has been looked after, a few of the some more benefits of Ni-Cd rechargeable batteries. They may be used for up to 500 full recharge cycles, which is on the higher side. The charge is also retained much more time when not being used. Losing only 1% of charge per day takes almost four months for the battery to be completely discharged.
Regardless of the Ni-Cd batteries costing more, having slightly lower voltage and the memory effect; their demand has not diminished because there is a significantly longer total lifetime than alkaline cells, which is what consumers look for when buying batteries – a long lasting battery. Even when your Ni-Cd battery appears to have come to the end o its life it is probably still possible to avoid the expense of replacing them by using the techniques outlined in this Recondition Old Batteries guide