For quite some time, nickel-cadmium was the only real 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 get customer’s acceptance. Today, lithium-ion is the fastest growing and the majority of promising battery chemistry.
Pioneer assist the lithium battery began in 1912 under G.N. Lewis however it was not until the early 1970s once the first non-rechargeable lithium batteries became commercially available. lithium may be the lightest of most metals, provides the greatest electrochemical potential and gives the most important energy density for weight.
Efforts to develop rechargeable lithium batteries failed because of safety problems. Due to 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 is safe, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first lithium-ion battery. Other manufacturers followed suit.
The electricity density of lithium-ion is usually twice that from the typical nickel-cadmium. There is certainly likelihood of higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium when it comes to discharge. The top cell voltage of three.6 volts allows battery pack designs with just one single cell. The majority of today’s cell phones 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 and no scheduled cycling must prolong the battery’s life. Furthermore, the self-discharge is less than half compared 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 have their drawbacks. It can be fragile and needs a protection circuit to keep up safe operation. Built in each pack, the protection circuit limits the peak voltage of each and every 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 utmost charge and discharge current on most packs are is limited to between 1C and 2C. Using these precautions in position, the chance of metallic lithium plating occurring on account of overcharge is virtually eliminated.
Aging is a concern with many Innovative battery technology and several manufacturers remain silent concerning this issue. Some capacity deterioration is noticeable after one year, regardless of if the battery is at use or not. Battery frequently fails after several years. It needs to be noted that other chemistries likewise have age-related degenerative effects. This is especially valid for nickel-metal-hydride if open to high ambient temperatures. As well, lithium-ion packs are acknowledged to have served for 5yrs in many applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every 6 months roughly. With your rapid progress, it is difficult to evaluate how good the revised battery will age.
Storage within a cool place slows growing older of lithium-ion (along with other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, the battery ought to be partially charged during storage. The manufacturer recommends a 40% charge.
The most economical lithium-ion battery with regards to cost-to-energy ratio will be the cylindrical 18650 (dimensions are 18mm x 65.2mm). This cell can be used for mobile computing as well as other applications that do not demand ultra-thin geometry. When a slim pack is essential, the prismatic lithium-ion cell is the perfect choice. These cells come in a higher cost in terms of stored energy.
High energy density – prospect of yet higher capacities.
Does not need prolonged priming when new. One regular charge is all that’s needed.
Relatively low self-discharge – self-discharge is less than half that of nickel-based batteries.
Low Maintenance – no periodic discharge is essential; there is absolutely no memory.
Specialty cells provides quite high current to applications including power tools.
Requires protection circuit to maintain voltage and current within safe limits.
Susceptible to aging, even if not being utilised – storage in a cool place at 40% charge decreases the aging effect.
Transportation restrictions – shipment of larger quantities can be susceptible to regulatory control. This restriction fails to relate to personal carry-on batteries.
Costly to manufacture – about 40 percent higher in price 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 first design, dating back towards the 1970s, works with 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, which happens to be soaked with electrolyte.
The dry polymer design offers simplifications regarding fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring well under one millimeter (.039 inches), equipment designers are still with their own imagination with regards to form, shape and size.
Unfortunately, the dry lithium-polymer suffers from poor conductivity. The interior resistance is way too high and cannot provide the current bursts required to power modern communication devices and spin up the hardrives of mobile computing equipment. Heating the cell to 60°C (140°F) and higher raises the conductivity, a requirement which is unsuitable for portable applications.
To compromise, some gelled electrolyte has been added. The commercial cells make use of a separator/ electrolyte membrane prepared from your same traditional porous polyethylene or polypropylene separator filled up with a polymer, which gels upon filling with 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 caught on as quickly as some analysts had expected. Its superiority to other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved – the truth is, the capacity 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 credit cards and other such applications.
Extremely low profile – batteries resembling the profile of a charge card are feasible.
Flexible form factor – manufacturers are certainly not bound by standard cell formats. With high volume, any reasonable size could 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.
Expensive to manufacture.
No standard sizes. Most cells are produced 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 permitted to bring on board?” We differentiate between two battery types: Lithium metal and lithium-ion.
Most lithium metal batteries are non-rechargeable and 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 the following 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 can 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 be aware of lithium content of a lithium-ion battery? Coming from a theoretical perspective, there is not any metallic lithium in a typical lithium-ion battery. There may be, however, equivalent lithium content that need to be considered. For the lithium-ion cell, this really is calculated at .3 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 two in parallel), this results in 4.8g. To stay underneath the 8-gram UN limit, the Outdoor Power Equipment battery packs you can bring is 96 Wh. This pack could include 2.2Ah cells in a 12 cells arrangement (4s3p). If the 2.4Ah cell were utilised instead, the pack will need to be limited to 9 cells (3s3p).
Restrictions on shipment of lithium-ion batteries
Anyone shipping lithium-ion batteries in large quantities is responsible to meet transportation regulations. This applies 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 must be shipped as “Class 9 miscellaneous hazardous material.” Cell capacity 18dexmpky the number of cells within a pack determine the lithium content.
Exception is offered to packs that contain below 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 is going to be required. Each package has to be marked that it contains lithium batteries.
All lithium-ion batteries should 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 needs to be separated in order to avoid short-circuiting and packaged in strong boxes.