What are Rechargeable Lithium Batteries?
Rechargeable batteries are those that can be reused for a long time. That means that the charge-discharge cycle of rechargeable batteries can be initiated by passing an electric current through the battery via a charger device. Rechargeable batteries have electrolytic chemicals that have an high degree of active life. That means, a rechargeable battery chemical can be activated and used even after it is apparently ‘exhausted’.
However, there is a limit to the use of a rechargeable battery, that is unless the active life of the batteries is completely exhausted. Depending on the type of electrolytic chemicals used, rechargeable batteries can be of types Nickel Metal Hydride (NiMH), Nickel Cadmium (Ni Cd), Lead acid rechargeable batteries and Lithium ion rechargeable batteries. The Lithium ion batteries are the ones with the highest energy density rates. A Typical Lithium ion battery has a cell voltage of 3.6 volts, which is the highest when compared to the other batteries (for instance, Ni MH batteries have a typical cell voltage of 1.2 volts and Lead acid batteries typically have a voltage of 2.2 volts). The Lithium ion batteries are also the most expensive of the other types of rechargeable batteries. The energy density of a battery refers to the stored energy in the battery expressed as a function of weight or volume.
The Lithium ion batteries are popularly preferred in laptop computers, cell phones and also in digital SLR cameras. The high energy density of the batteries coupled with the battery property of low rate of self discharge, makes these batteries ideal for long term use. That means, the Lithium ion batteries do not run the risk of getting dead if not used for a long time. This particular feature also enables the Lithium ion batteries to be used in emergency devices like emergency flashlights and smoke alarms. An estimate of the self discharge rate of the lithium ion batteries can be understood from the fact that, the batteries lose about 5%-10% of their storage capacity every year from the year of manufacturing.
Different companies are using commercially different Lithium compound cathodes. The SONY cells started their Li-ion batteries in 1991 by using a Lithium Cobalt oxide cathode and a graphite anode. Sanyo also uses similar technologies. Other companies like the LG, NEC and Samsung use the Li-Manganese spinel as the cathode.
However, there are also an important point that must be remembered in case of lithium ion batteries. These batteries use highly volatile electrolytic combination and they pose a risk of explosion if the batteries are short-circuited or overheated. Even prolonged exposure to direct sunlight can be hazardous in case of lithium ion rechargeable batteries. It is best to buy only those Lithium ion batteries, whose manufacturers commit to rigorous quality standards in the making of the battery.
