What are the types of Laptop Batteries?
The various types of Ni-Cd batteries and its applications
Very few of us think about the battery life of our laptop till it dies. It is practically taken for granted, using it with the screen as bright as possible, and plugging in external devices. Now, the question is which battery to get for a reliable operation? The objective is to know which battery technology works for the laptop that one has. There have been several technologies involved with laptop batteries, but there are three particular laptop battery types in the market. These are, Nickel Cadmium, Nickel Metal Hydride, and Lithium Ion.
There are generally three types of batteries that one can buy for laptops. The discussion below may be helpful for deciding on the type of battery that one should get for the notebook.
Nickel Cadmium (NiCd) Batteries
Ni-Cad batteries were the first known rechargeable batteries manufactured for laptop. They are low cast batteries, having high output. These batteries are not in use now, because of its weight, and incompatibility with the newer laptop/notebook versions. However, it remains popular for its use in portable electronic toys, and as replacements for primary cells, such as heavy duty or alkaline. The abbreviation, NiCad is a registered trademark of SAFT Corporation, and is usually not used to refer to other nickel-cadmium batteries. The weight/energy ratio of the batteries makes it convenient to be used for electric cars, and as start batteries for airplanes. Since these batteries come in different shapes and sizes, it has a niche market area for cordless and wireless telephones, emergency lighting, model airplanes, as well as power tools.
A single cell of nickel cadmium battery has a potential of 1.2 volts, which is lower than the other popular primary cell voltage of 1.5 volts. This is the reason why NiCd batteries cannot be used as a replacement of the primary cells. However, the NiCd batteries maintain a constant potential, unlike the alkaline primary cell batteries. The batteries are available in several sizes, providing various voltage specifications. Besides the single cell of 1.2 volts, 7.2, 9.6, and 12 V NiCd battery packs are available, which are made up of several cells connected in series.
Nickel Metal Hydride (NiMh) Batteries
NiMh (Nickel Metal Hydride) is a rechargeable battery, similar to the NiCd batteries, that we have just discussed. Instead of Cadmium, NiMh batteries have hydrogen-absorbing alloy for the anode. With Nickel as its cathode, NiMh batteries have capacity two or three times than that of NiCd batteries, of equivalent size. In comparison to the lithium-ion battery, NiMh batteries have less volumetric energy and its self discharge is higher.
Some old laptops are still powered by NiMh batteries. NiMh batteries have proved to be more reliable than NiCd batteries, and with NiMh batteries providing higher output, its introduction has been a big step for laptop technology. Besides laptops, NiMh batteries have applications in hybrid vehicles, and consumer electronics. It is known to have been used for Alstom Citadis low floor tram ordered for Nice , France . These batteries find applications in digital cameras, flashlights, and other consumer electronics, owing to the moderate current drain of the devices. Since NiCd has lower internal resistance, it still finds applications in high current drain devices, such as, cordless power tools and RC cars.
Lithium Ion (Li-ion) Batteries
Lithium-ion batteries are being mostly used in the present day laptops. They are lighter than the NiCd or the NiMh batteries, and unlike NiCd batteries, have no memory effect. This makes Li-ion batteries most effective and popular for use in various laptop power sources. However, Li-ion batteries are more expensive than the other two. The batteries are also being used in various portable electronic equipment, and its increasing use is contributed to its weight-energy ratio, its 'no memory effect', and slow loss of charge when not in use.
Being the third lightest element, use of Lithium in the battery, makes it much lighter compared to the batteries using heavier metals. However, the weight of the battery comes from the bulk of the electrodes, which is essentially the housing for the ions. Some manufacturers of the batteries claim, that Li-ion batteries do not 'self-discharge' in its proper sense, and any self discharge perceived is a permanent loss of capacity. In the so called 'smart Li-ion' batteries, there is a self discharging effect, owing to the small constant drain of the built-in voltage monitoring circuit.
Li-ion batteries have a disadvantage in its life span, which depend upon its shelf-life, regardless of the fact whether it has been charged or not. With others, the life-span mostly depend upon the number of charge/discharge cycle that they go through. Therefore older Li-ion batteries will not last as the ones freshly manufactured.
Some suggestions
The first and foremost criteria in purchasing a battery for a laptop, is to look for the manufacturer. In case one intends to buy a battery manufactured by the laptop manufacturer, such as, Sony, Compaq, Dell, etc., one need not look further. However, these batteries are mostly not manufactured by the concerned laptop manufacturer, but are branded by them to endorse the quality level of the product. There are third party products available, which may be right for the laptop. Buying third part products may provide one with extra benefits, such as, they are cheaper, provides extended guarantees, etc. Talking about guarantee, the battery one buys should be guaranteed for at least one year. But then again, you must be aware of the reputation of the third part manufacturer.
The power rating is another specification that one should look into. There are two main ratings that one should look for when buying a battery: Volts and Amperes. The laptop batteries have their ratings shown in Volts and milliamperes, since these batteries do not carry large amount of power as compared to, for example, a car battery. The term mAh denotes the energy charge that the battery holds, and the length of time the laptop will run before the battery needs to be charged. It is to be remembered that batteries with higher mAh (milliampere hour) will last longer.
|
|
|
Recommended
Battery Stores:
|
|
|
|
