Nickel Metal Hydride (Ni-MH)

Nickel Metal Hydride (Ni-MH) batteries brought revolution to the mobile computing segment. These rechargeable batteries don’t have any heavy metals cadmium, lead or mercury and are environmentally friendly. Unlike Ni-Cd they do not suffer from the memory effect, so they can be charged at any time.

Ni-MH had many advantages over the Ni-Cd batteries and was used in MP3 players, digital cameras, CD players, portable media players and notebooks. The batteries have higher mAh (milliampere hour) making them last for longer periods. An average Ni-MH battery can last about 500-1000 cycles. A Ni-MH battery has a similar weight of a Ni-Cd battery but the operating time of battery is much longer.

Lithium Ion (Li-Ion)

You can find this kind of battery on many current mobile devices and notebooks. Yes, this is the most commonly used battery as it is lighter than other types and can carry more power than the other two. These batteries are not relatively new, actually the technology was invented in 1912 by G.N Lewis Back, but due to safety measures they were held back and not commercialized until the late 1970’s.

The battery consists of Lithium Cobalt Oxide as an anode and porus graphite as cathode separated by an electrolytic substance. Lithium being a highly reactive substance, it reacts with graphite to produce high energy as a result atomic bonds of lithium can store more energy. The power loss in lithium ion batteries is minimal. On an average a Li-Ion battery loses only 5% of its charge, so a 100gms battery can hold 15 hours of charge.

A Li-Ion battery can handle many charging cycles as this doesn’t contain any memory effect, so Li-Ion batteries can be charged at any time, even if the battery still has 50% of charge left. There is also no need of charging and discharging at the initial stage. The performance of the battery is similar to the first charge and to the hundredth charge. On an average use a Li-Ion battery can last up to 3 years or 2000 cycles with new generation batteries able to last for 20 000 cycles.

You may have heard stories about exploding batteries. They are true but rare, the fault of manufacturing defects, when the batteries heat up too much the electrolyte ignites a spark that leads to fire. This problem is no longer an issue. These days the power supply is tripped off when it gets overheated.