Why is the Lithium-ion Battery the Quickest Developing Battery Technology.

How Lithium Ion Batteries were formulated.

Pioneer investigation with the Lithium Ion battery commenced in 1912 under G.N. Lewis however it was not until the early 1970s that the first non-rechargeable lithium batteries became commercially accessible. Attempts to generate rechargeable lithium batteries followed in the 1980s, but failed because of safety problems.

Lithium is the lightest of all metals, has the greatest electrochemical potential and delivers the largest energy density per weight. Rechargeable batteries utilizing lithium metal anodes (negative electrodes) are capable of providing both good voltage and outstanding capacity, generating an extraordinary high energy density.

After much research on rechargeable lithium batteries during the 1980s, it was discovered that cycling causes changes on the lithium electrode. These transformations, which are part of regular wear and tear, lessen the thermal stability, triggering potential thermal runaway situations. As soon as this happens, the cell temperature quickly approaches the melting point of lithium, resulting in a violent response called "venting with flame". A high number of rechargeable lithium batteries sent to Japan had to be recalled in 1991 after a battery in a cellular phone released flaming gases and inflicted burns to a person's face.

Because of the inherent instability of lithium metal, especially during charging, investigation shifted to a non-metallic lithium battery by using lithium ions. Although slightly reduced in energy density than lithium metal, the Li-ion is safe, as long as certain safety measures are taken when charging and discharging. In 1991, the Sony Corporation commercialized the first Li-ion battery. Other producers followed suit. Today, the Li-Ion Battery is the quickest growing and most promising battery chemistry.

The energy density of the Lithium Ion Battery is normally twice that of the typical Ni-Cd Battery. Enhancements in electrode active components have the potential of increasing the energy density near to three times that of the Nickel cadmium. In addition to good capacity, the load attributes are reasonably good and behave similarly to the Ni-Cd in terms of discharge qualities (similar shape of discharge profile, but other voltage). The flat discharge curve provides effective utilization of the saved electrical power in a useful voltage range.

The Li-ion Battery is a low maintenance battery, an advantage that most other technologies are unable to claim. There is no memory and no scheduled cycling is needed to extend the battery's life. In addition, the self discharge is less than half compared to Ni-Cd and NiMH, making the Li-ion well suited for current fuel gauge products.

The high cell voltage of Lithium-Ion Battery allows the production of battery packs made up of only a single cell. A great number of of todays mobile phones function on a solitary cell, an advantage that simplifies battery engineering. Supply voltages of electronic products have been shifting lower, which in turn needs less cells per battery pack. To keep the same power, though, greater currents are required. This reinforces the significance of very low cell resistance to allow free flow of current.

Benefits and Limitations of Li-Ion Batteries.

1. Advantages

a. Excellent energy density, ability for yet larger capacities.

b. •Relatively low self-discharge, self-discharge is less than fifty percent that of Ni-Cd and NiMH.

•Low Maintenance, no occaisional discharge is needed; no memory.

2. Limitations

a. Requires protection circuit, protection circuit restricts voltage and current. Battery is safe if not provoked.

b. •Subject to aging, even if not in use, keeping the battery in a temperature controlled situation and at 40 percent state-of-charge minimises the aging impact.

c. •Moderate discharge current.

d. •Subject to transportation rules, shipment of greater quantities of Li-ion batteries may also be subject to regulatory control. This restriction does not apply to personal carry-on batteries.

e. •Costly to manufacture, about 40 percent higher in cost than Ni-Cd. Better production procedures and replacement of rare metals with lower cost possibilities will doubtless cut the price.

f. •Not fully developed, adjustments in metal and chemical combinations have an effect on battery assessment outcomes, particularly with some short test procedures.