The use of lithium ion, li-ion batteries has grown significantly in recent years. They offer some distinct advantages and improvements over other forms of battery technology.
However, like all technologies, lithium ion batteries have their advantages and disadvantages.
To gain the best from the li-ion battery technology, it is necessary to understand not only the advantages, but also the limitations or disadvantages of the technology. In this way they can be used in a manner that plays to their strengths in the best way.
Lithium ion battery advantages
There are many advantages to using a li-ion cell of battery. These li-ion battery advantages include:
- High energy density: The high energy density is one of the chief advantages of lithium ion battery technology. With electronic equipment such as mobile phones needing to operate longer between charges while still consuming more power, there is always a need to batteries with a much higher energy density. In addition to this, there are many power applications from power tools to electric vehicles. The much higher power density offered by lithium ion batteries is a distinct advantage. Electric vehicles also need a battery technology that has a high energy density.
- Self-discharge: One issue with many rechargeable batteries is the self discharge rate. Lithium ion cells is that their rate of self-discharge is much lower than that of other rechargeable cells such as Ni-Cad and NiMH forms. It is typically around 5% in the first 4 hours after being charged but then falls to around 1 or 2% per month.
- Low maintenance: One major lithium ion battery advantage is that they do not require and maintenance to ensure their performance. Ni-Cad cells required a periodic discharge to ensure that they did not exhibit the memory effect. As this does not affect lithium ion cells, this process or other similar maintenance procedures are not required.
- No requirement for priming: Some rechargeable cells need to be primed when they receive their first charge. There is no requirement for this with lithium ion cells and batteries.
- Variety of types available: There are several types of lithium ion cell available. This advantage of lithium ion batteries can mean that the right technology can be used for the particular application needed. Some forms of lithium ion battery provide a high current density and are ideal for consumer mobile electronic equipment. Others are able to provide much higher current levels and are ideal for power tools and electric vehicles.
Lithium ion battery disadvantages
Like the use of any technology, there are some disadvantages that need to be balanced against the benefits. The li-ion battery disadvantages include:
- Protection required: Lithium ion cells and batteries are not as robust as some other rechargeable technologies. They require protection from being over charged and discharged too far. In addition to this, they need to have the current maintained within safe limits. Accordingly one lithium ion battery disadvantage is that they require protection circuitry incorporated to ensure they are kept within their safe operating limits. Fortunately with modern integrated circuit technology, this can be relatively easily incorporated into the battery, or within the equipment if the battery is not interchangeable. Incorporation of the battery management circuitry enables li-ion batteries to be used without any special knowledge. They can be left on charge and after the battery is fully charged the charger will cut the supply to it.
- Ageing : One of the major lithium ion battery disadvantages for consumer electronics is that lithium ion batteries suffer from ageing. Not only is this time or calendar dependent, but it is also dependent upon the number of charge discharge cycles that the battery has undergone. Often batteries will only be able to withstand 500 - 1000 charge discharge cycles before their capacity falls. With the development of li-ion technology, this figure is increasing, but after a while batteries may need replacing and this can be an issue if they are embedded in the equipment.
When a typical consumer lithium cobalt oxide, LCO battery or cell needs to be stored it should be partially charged - around 40% to 50% and kept in a cool storage area. Storage under these conditions will help increase the life.
- Transportation: This li-ion battery disadvantage has come to the fore in recent years. Many airlines limit the number of lithium ion batteries they take, and this means their transportation is limited to ships. For air travellers, lithium ion batteries often need to be in carry-on luggage, although with the security position, this may change from time to time. But the number of batteries may be limited. Any lithium ion battieries carried separately must be protected against short circuits by protective covers, etc.
- Cost: A major lithium ion battery disadvantage is their cost. Typically they are around 40% more costly to manufacture than Nickel cadmium cells. This is a major factor when considering their use in mass produced consumer items where any additional costs are a major issue.
- Immature technology: Although lithium ion batteries have been available for many years, it can still be considered an immature technology by some as it is very much a developing area. This can be a disadvantage in terms of the fact that the technology does not remain constant. However as new lithium ion technologies are being developed all the time, it can also be an advantage as better solutions are coming available.
Li-ion battery technology has very many distinct advantages. Accordingly the technology is widely used, and this is only set to increase. Understanding the advantages as well as the disadvantages or limitations enables the best use to be made of the battery technology.
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