For many years, nickel-cadmium have 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 During the early 1990s, fighting nose-to-nose to acquire customer’s acceptance. Today, lithium-ion is the fastest growing and most promising battery chemistry.
Pioneer deal with the lithium battery began in 1912 under G.N. Lewis however it was not until the early 1970s when 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.
Tries to develop rechargeable lithium batteries failed as a result of safety problems. Because of the inherent instability of lithium metal, especially during charging, research moved 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 very first lithium-ion battery. Other manufacturers followed suit.
The vitality density of lithium-ion is generally twice that relating to the conventional nickel-cadmium. There may be likelihood of higher energy densities. The burden characteristics are reasonably good and behave similarly to nickel-cadmium with regards to discharge. The high cell voltage of three.6 volts allows battery pack designs with just one cell. Almost 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 actually a low maintenance battery, an edge that a majority of other chemistries cannot claim. There is not any memory with out scheduled cycling is required to prolong the battery’s life. In addition, the self-discharge is less than half when compared 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 preserve safe operation. That are part of each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. Additionally, the cell temperature is monitored in order to avoid temperature extremes. The most charge and discharge current on most packs are has limitations to between 1C and 2C. By using these precautions in position, the potential of metallic lithium plating occurring as a result of overcharge is virtually eliminated.
Aging is a concern with a lot of Innovative battery technology and several manufacturers remain silent about this issue. Some capacity deterioration is noticeable after 1 year, regardless of if the battery is at use or not. Battery frequently fails after 2 or 3 years. It ought to be noted that other chemistries also have age-related degenerative effects. This is also true for nickel-metal-hydride if open to high ambient temperatures. At the same time, lithium-ion packs are known to have served for five-years in a few applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months or so. With your rapid progress, it is difficult to evaluate how good the revised battery will age.
Storage in a cool place slows growing older of lithium-ion (along with other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). Moreover, battery must be partially charged during storage. The maker recommends a 40% charge.
The most economical lithium-ion battery with regards to cost-to-energy ratio may be the cylindrical 18650 (size is 18mm x 65.2mm). This cell is commonly used for mobile computing along with other applications which do not demand ultra-thin geometry. If a slim pack is necessary, the prismatic lithium-ion cell is the ideal choice. These cells come in a higher cost with regards to stored energy.
High energy density – likelihood of yet higher capacities.
Does not need prolonged priming when new. One regular charge is perhaps all that’s needed.
Relatively low self-discharge – self-discharge is less than half that from nickel-based batteries.
Low Maintenance – no periodic discharge is required; there is no memory.
Specialty cells offers very high current to applications including power tools.
Requires protection circuit to keep voltage and current within safe limits.
At the mercy of aging, even though not being utilised – storage inside a cool place at 40% charge decreases the aging effect.
Transportation restrictions – shipment of larger quantities can be subject to regulatory control. This restriction is not going to relate to personal carry-on batteries.
Costly to manufacture – about forty percent 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, going back on the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or teams of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
The dry polymer design offers simplifications when it comes to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring as little as one millimeter (.039 inches), equipment designers remain for their own imagination regarding form, size and shape.
Unfortunately, the dry lithium-polymer is experiencing poor conductivity. The inner resistance is just too high and cannot provide you with the current bursts required to power modern communication devices and spin within the hard drives of mobile computing equipment. Heating the cell to 60°C (140°F) and higher increases the conductivity, a requirement that may be unsuitable for portable applications.
To compromise, some gelled electrolyte has been added. The commercial cells work with a separator/ electrolyte membrane prepared through the same traditional porous polyethylene or polypropylene separator full of a polymer, which gels upon filling using the liquid electrolyte. Thus the commercial lithium-ion polymer cells are really similar in chemistry and materials for their liquid electrolyte counter parts.
Lithium-ion-polymer has not yet caught on as fast as some analysts had expected. Its superiority to many other systems and low manufacturing costs is not realized. No improvements in capacity gains are achieved – in fact, the capability is slightly less than that of the standard lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, including batteries for credit cards along with other such applications.
Extremely low profile – batteries resembling the profile of a credit card are feasible.
Flexible form factor – manufacturers are not bound by standard cell formats. With good volume, any reasonable size may be produced economically.
Lightweight – gelled electrolytes enable simplified packaging through the elimination of the metal shell.
Improved safety – more immune 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 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 allowed 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 found 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 not more than 25 grams could be carried in carry-on baggage if individually protected to prevent short circuits and are confined to two spare batteries per person.
How do I be aware of lithium content of your lithium-ion battery? From the theoretical perspective, there is no metallic lithium in the typical lithium-ion battery. There may be, however, equivalent lithium content that must definitely be considered. For a lithium-ion cell, this is certainly 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 two in parallel), this results in 4.8g. To keep 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). When the 2.4Ah cell were used instead, the rest will need to be confined to 9 cells (3s3p).
Restrictions on shipment of lithium-ion batteries
Anyone shipping lithium-ion batteries in bulk is responsible to meet 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 quantity of cells in the pack determine the lithium content.
Exception is provided to packs which contain less than 8 grams of lithium content. If, however, a shipment contains greater than 24 lithium cells or 12 lithium-ion battery packs, special markings and shipping documents will be required. Each package has to be marked that this contains lithium batteries.
All lithium-ion batteries must be tested according to specifications detailed in UN 3090 regardless of lithium content (UN manual of Tests and Criteria, Part III, subsection 38.3). This precaution safeguards against the shipment of flawed batteries.
Cells & batteries should be separated to avoid short-circuiting and packaged in strong boxes.