For quite some time, nickel-cadmium had been really the only suitable battery for Custom test and measurement equipment battery packs from wireless communications to mobile computing. Nickel-metal-hydride and lithium-ion emerged In the early 1990s, fighting nose-to-nose to gain customer’s acceptance. Today, lithium-ion is the fastest growing and the majority of promising battery chemistry.
Pioneer work with the lithium battery began in 1912 under G.N. Lewis however it was not before the early 1970s once the first non-rechargeable lithium batteries became commercially available. lithium will be the lightest of all metals, has got the greatest electrochemical potential and gives the largest energy density for weight.
Tries to develop rechargeable lithium batteries failed as a result of safety problems. Due to 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 is safe, 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 electricity density of lithium-ion is usually twice those of the regular nickel-cadmium. There is certainly possibility of higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium with regards to discharge. Our prime cell voltage of 3.6 volts allows battery pack designs with just one cell. Most of today’s cell phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion is a low maintenance battery, a benefit that a majority of other chemistries cannot claim. There is no memory with no scheduled cycling is required to prolong the battery’s life. Moreover, the self-discharge is not even half in comparison to nickel-cadmium, making lithium-ion well best for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.
Despite its overall advantages, lithium-ion does have its drawbacks. It can be fragile and requires a protection circuit to keep up safe operation. Included in each pack, the security circuit limits the peak voltage of each and every cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored in order to avoid temperature extremes. The most charge and discharge current on the majority of packs are is restricted to between 1C and 2C. Using these precautions in place, the possibility of metallic lithium plating occurring because of overcharge is virtually eliminated.
Aging is a concern with many Rechargeable mobile phone batteries and several manufacturers remain silent relating to this issue. Some capacity deterioration is noticeable after 12 months, if the battery is in use or otherwise not. Battery frequently fails after 2 or 3 years. It must be noted that other chemistries also provide age-related degenerative effects. This is especially valid for nickel-metal-hydride if subjected to high ambient temperatures. Simultaneously, lithium-ion packs are acknowledged to have served for 5 years in a few applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months roughly. With such rapid progress, it is sometimes complicated to gauge how good the revised battery will age.
Storage in the cool place slows getting older of lithium-ion (as well as other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, battery needs to be partially charged during storage. The maker recommends a 40% charge.
The most economical lithium-ion battery regarding cost-to-energy ratio may be the cylindrical 18650 (dimension is 18mm x 65.2mm). This cell is commonly used for mobile computing along with other applications which do not demand ultra-thin geometry. In case a slim pack is necessary, the prismatic lithium-ion cell is the best choice. These cells come in a higher cost regarding stored energy.
High energy density – likelihood of yet higher capacities.
Is not going to need prolonged priming when new. One regular charge is 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 essential; there is not any memory.
Specialty cells offers very high current to applications including power tools.
Requires protection circuit to keep up voltage and current within safe limits.
Subject to aging, even when not being used – storage inside a cool place at 40% charge cuts down on the aging effect.
Transportation restrictions – shipment of larger quantities might be at the mercy of regulatory control. This restriction does not affect personal carry-on batteries.
Costly 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 kind of electrolyte used. The very first design, dating back on the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that fails to conduct electricity but allows ions exchange (electrically charged atoms or sets of atoms). The polymer electrolyte replaces the traditional porous separator, that is soaked with electrolyte.
The dry polymer design offers simplifications when it comes to fabrication, ruggedness, safety and thin-profile geometry. Using a cell thickness measuring as low as one millimeter (.039 inches), equipment designers stay for their own imagination with regards 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 found it necessary to power modern communication devices and spin in the hardrives 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 use a separator/ electrolyte membrane prepared in the same traditional porous polyethylene or polypropylene separator loaded with a polymer, which gels upon filling together with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are extremely similar in chemistry and materials with their liquid electrolyte counter parts.
Lithium-ion-polymer has not caught on as quickly as some analysts had expected. Its superiority for some other systems and low manufacturing costs is not realized. No improvements in capacity gains are achieved – the truth is, the ability is slightly less than that of the conventional lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, like batteries for a credit card as well as other such applications.
Suprisingly low profile – batteries resembling the profile of credit cards are feasible.
Flexible form factor – manufacturers usually are not bound by standard cell formats. Rich in volume, any reasonable size might be produced economically.
Lightweight – gelled electrolytes enable simplified packaging by eliminating the metal shell.
Improved safety – more resistant to overcharge; less possibility of electrolyte leakage.
Lower energy density and decreased cycle count when compared with lithium-ion.
Costly to manufacture.
No standard sizes. Most cells are designed for top volume consumer markets.
Higher cost-to-energy ratio than lithium-ion
Restrictions on lithium content for air travel
Air travelers ask the question, “Simply how much lithium inside a battery am I capable to bring aboard?” We differentiate between two battery types: Lithium metal and lithium-ion.
Most lithium metal batteries are non-rechargeable and 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 the next lithium content:
– 2 grams for lithium metal or lithium alloy batteries
– 8 grams for lithium-ion batteries
Lithium-ion batteries exceeding 8 grams but at most 25 grams may be carried in carry-on baggage if individually protected in order to avoid short circuits and they are limited by two spare batteries per person.
How do you be aware of lithium content of a lithium-ion battery? From the theoretical perspective, there is no metallic lithium in a typical lithium-ion battery. There may be, however, equivalent lithium content that need to be considered. To get a lithium-ion cell, this is calculated at .3 times the rated capacity (in ampere-hours).
Example: A 2Ah 18650 Li-ion cell has .6 grams of lithium content. Over a typical 60 Wh laptop battery with 8 cells (4 in series and 2 in parallel), this adds up to 4.8g. To remain within the 8-gram UN limit, the Cordless tool battery packs you are able to bring is 96 Wh. This pack could include 2.2Ah cells inside a 12 cells arrangement (4s3p). In the event the 2.4Ah cell were used instead, the rest would have to be confined to 9 cells (3s3p).
Restrictions on shipment of lithium-ion batteries
Anyone shipping lithium-ion batteries in mass is responsible to satisfy 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 needs to be shipped as “Class 9 miscellaneous hazardous material.” Cell capacity 18dexmpky the quantity of cells inside a pack determine the lithium content.
Exception is offered to packs which contain less than 8 grams of lithium content. If, however, a shipment contains more than 24 lithium cells or 12 lithium-ion battery packs, special markings and shipping documents will likely be required. Each package has to be marked that it contains lithium batteries.
All lithium-ion batteries has to be tested as outlined by specifications detailed in UN 3090 no matter what lithium content (UN manual of Tests and Criteria, Part III, subsection 38.3). This precaution safeguards up against the shipment of flawed batteries.
Cells & batteries has to be separated to avoid short-circuiting and packaged in strong boxes.