For quite some time, nickel-cadmium was the sole suitable battery for Custom test and measurement equipment battery packs from wireless communications to mobile computing. Nickel-metal-hydride and lithium-ion emerged In early 1990s, fighting nose-to-nose to gain customer’s acceptance. Today, lithium-ion is definitely the fastest growing and a lot promising battery chemistry.
Pioneer work together with the lithium battery began in 1912 under G.N. Lewis but it was not till the early 1970s if the first non-rechargeable lithium batteries became commercially available. lithium is definitely the lightest of metals, has the greatest electrochemical potential and gives the greatest energy density for weight.
Efforts to develop rechargeable lithium batteries failed as a result of safety problems. Because of the inherent instability of lithium metal, especially during charging, research shifted to a non-metallic lithium battery using lithium ions. Although slightly lower in energy density than lithium metal, lithium-ion remains safe and secure, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the 1st lithium-ion battery. Other manufacturers followed suit.
The vitality density of lithium-ion is normally twice those of the typical nickel-cadmium. There exists possibility of higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium regarding discharge. Our prime cell voltage of three.6 volts allows battery pack designs with just one cell. Nearly all of today’s mobile phone devices run on one cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion is really a low maintenance battery, an advantage that most other chemistries cannot claim. There is not any memory with out scheduled cycling is necessary to prolong the battery’s life. In addition, the self-discharge is less than half in comparison with nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.
Despite its overall advantages, lithium-ion have their drawbacks. It can be fragile and needs a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage for each cell during charge and prevents the cell voltage from dropping too low on discharge. Moreover, the cell temperature is monitored to stop temperature extremes. The highest charge and discharge current on most packs are has limitations to between 1C and 2C. By using these precautions in position, the opportunity of metallic lithium plating occurring because of overcharge is virtually eliminated.
Aging is a concern with many Lithium-Polymer laptop replacement batteries and several manufacturers remain silent about this issue. Some capacity deterioration is noticeable after one year, if the battery is within use or otherwise. Battery frequently fails after two or three years. It should be noted that other chemistries have age-related degenerative effects. This is also true for nickel-metal-hydride if open to high ambient temperatures. As well, lithium-ion packs are acknowledged to have served for five-years in a few applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every half a year or more. By using these rapid progress, it is not easy to gauge how well the revised battery will age.
Storage in the cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). Additionally, battery must be partially charged during storage. The company recommends a 40% charge.
One of the most economical lithium-ion battery in terms of cost-to-energy ratio is the cylindrical 18650 (dimension is 18mm x 65.2mm). This cell is utilized for mobile computing and also other applications that do not demand ultra-thin geometry. When a slim pack is necessary, the prismatic lithium-ion cell is the ideal choice. These cells come with a higher cost in terms of stored energy.
High energy density – potential for yet higher capacities.
Will not need prolonged priming when new. One regular charge will be all that’s needed.
Relatively low self-discharge – self-discharge is not even half that of nickel-based batteries.
Low Maintenance – no periodic discharge is necessary; there is no memory.
Specialty cells can provide very high current to applications including power tools.
Requires protection circuit to preserve voltage and current within safe limits.
Susceptible to aging, even when not in use – storage inside a cool place at 40% charge lessens the aging effect.
Transportation restrictions – shipment of larger quantities could be subject to regulatory control. This restriction fails to pertain to personal carry-on batteries.
Expensive to manufacture – about 40 % higher in cost than nickel-cadmium.
Not fully mature – metals and chemicals are changing over a continuing basis.
The lithium-polymer differentiates itself from conventional battery systems in the sort of electrolyte used. The very first design, dating back on the 1970s, utilizes a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that is not going to conduct electricity but allows ions exchange (electrically charged atoms or categories of atoms). The polymer electrolyte replaces the standard porous separator, that is soaked with electrolyte.
The dry polymer design offers simplifications when it comes to fabrication, ruggedness, safety and thin-profile geometry. By using a cell thickness measuring less than one millimeter (.039 inches), equipment designers remain to their own imagination when it comes to form, size and shape.
Unfortunately, the dry lithium-polymer is experiencing poor conductivity. The inner resistance is way too high and cannot provide the current bursts necessary to power modern communication devices and spin up the hard drives of mobile computing equipment. Heating the cell to 60°C (140°F) and higher raises the conductivity, a requirement that may be unsuitable for portable applications.
To compromise, some gelled electrolyte has become added. The commercial cells utilize a separator/ electrolyte membrane prepared through the same traditional porous polyethylene or polypropylene separator filled with a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are very similar in chemistry and materials on their liquid electrolyte counter parts.
Lithium-ion-polymer has not caught on as fast as some analysts had expected. Its superiority with other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved – the truth is, the capability is slightly less than that of the regular lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, including batteries for charge cards as well as other such applications.
Suprisingly low profile – batteries resembling the profile of a credit card are feasible.
Flexible form factor – manufacturers will not be bound by standard cell formats. With higher volume, any reasonable size may be produced economically.
Lightweight – gelled electrolytes enable simplified packaging by reducing the metal shell.
Improved safety – more proof against overcharge; less chance for electrolyte leakage.
Lower energy density and decreased cycle count in comparison with lithium-ion.
Costly to manufacture.
No standard sizes. Most cells are made for high volume consumer markets.
Higher cost-to-energy ratio than lithium-ion
Restrictions on lithium content for air travel
Air travelers ask the question, “Exactly how much lithium in a battery am I able to bring on board?” We differentiate between two battery types: Lithium metal and lithium-ion.
Most lithium metal batteries are non-rechargeable and therefore are employed in film cameras. Lithium-ion packs are rechargeable and power laptops, cellular phones and camcorders. Both battery types, including spare packs, are allowed as carry-on but cannot exceed these lithium content:
– 2 grams for lithium metal or lithium alloy batteries
– 8 grams for lithium-ion batteries
Lithium-ion batteries exceeding 8 grams but a maximum of 25 grams may be carried in carry-on baggage if individually protected to avoid short circuits and they are limited to two spare batteries per person.
How do I know the lithium content of the lithium-ion battery? From a theoretical perspective, there is not any metallic lithium in a typical lithium-ion battery. There exists, however, equivalent lithium content that must definitely be considered. For any lithium-ion cell, this really is calculated at .three times the rated capacity (in ampere-hours).
Example: A 2Ah 18650 Li-ion cell has .6 grams of lithium content. On a typical 60 Wh laptop battery with 8 cells (4 in series and 2 in parallel), this results in 4.8g. To stay within the 8-gram UN limit, the Cordless tool battery packs it is possible to bring is 96 Wh. This pack could include 2.2Ah cells within a 12 cells arrangement (4s3p). If the 2.4Ah cell were utilized instead, the rest will have to be confined to 9 cells (3s3p).
Restrictions on shipment of lithium-ion batteries
Anyone shipping lithium-ion batteries in bulk is responsible to fulfill transportation regulations. This is applicable to domestic and international shipments by land, sea and air.
Lithium-ion cells whose equivalent lithium content exceeds 1.5 grams or 8 grams per battery pack has to be shipped as “Class 9 miscellaneous hazardous material.” Cell capacity 18dexmpky the volume of cells in a pack determine the lithium content.
Exception is given to packs that include under 8 grams of lithium content. If, however, a shipment contains a lot more than 24 lithium cells or 12 lithium-ion battery packs, special markings and shipping documents is going to be required. Each package has to be marked that it contains lithium batteries.
All lithium-ion batteries has to be tested in accordance with specifications detailed in UN 3090 no matter lithium content (UN manual of Tests and Criteria, Part III, subsection 38.3). This precaution safeguards versus the shipment of flawed batteries.
Cells & batteries should be separated to avoid short-circuiting and packaged in strong boxes.