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 the early 1990s, fighting nose-to-nose to gain customer’s acceptance. Today, lithium-ion may be the fastest growing and the majority of promising battery chemistry.
Pioneer work together with the lithium battery began in 1912 under G.N. Lewis however it had not been till the early 1970s if the first non-rechargeable lithium batteries became commercially available. lithium is definitely the lightest of all the metals, offers the greatest electrochemical potential and gives the greatest energy density for weight.
Attempts to develop rechargeable lithium batteries failed because 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 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 electricity density of lithium-ion is normally twice those of the standard nickel-cadmium. There exists potential for higher energy densities. The stress characteristics are reasonably good and behave similarly to nickel-cadmium regarding discharge. Our prime cell voltage of 3.6 volts allows battery pack designs with just one single cell. Nearly all of today’s cellphones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion can be a low maintenance battery, a plus that a lot of other chemistries cannot claim. There is not any memory with no scheduled cycling is required to prolong the battery’s life. In addition, the self-discharge is less than half compared to 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 does have its drawbacks. It really is fragile and requires a protection circuit to keep 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. Furthermore, the cell temperature is monitored in order to avoid temperature extremes. The maximum charge and discharge current on the majority of packs are is limited to between 1C and 2C. With these precautions set up, the possibility of metallic lithium plating occurring on account of overcharge is virtually eliminated.
Aging is an issue with a lot of Innovative battery technology and a lot of manufacturers remain silent concerning this issue. Some capacity deterioration is noticeable after one year, if the battery is in use or otherwise not. The battery frequently fails after several years. It must be noted that other chemistries likewise have age-related degenerative effects. This is also true for nickel-metal-hydride if open to high ambient temperatures. Simultaneously, lithium-ion packs are known to have served for 5 years in many applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every 6 months or so. With such rapid progress, it is difficult to gauge how good the revised battery will age.
Storage in a cool place slows aging of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). Additionally, battery should be partially charged during storage. The manufacturer recommends a 40% charge.
One of the most economical lithium-ion battery regarding cost-to-energy ratio may be the cylindrical 18650 (dimensions are 18mm x 65.2mm). This cell is commonly used for mobile computing along with other applications which do not demand ultra-thin geometry. When a slim pack is essential, the prismatic lithium-ion cell is the best choice. These cells come with a higher cost when it comes to stored energy.
High energy density – prospect of 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 relating to nickel-based batteries.
Low Maintenance – no periodic discharge is necessary; there is no memory.
Specialty cells provides quite high current to applications such as power tools.
Requires protection circuit to keep voltage and current within safe limits.
Subjected to aging, even if not being utilised – storage in the cool place at 40% charge cuts down on the aging effect.
Transportation restrictions – shipment of larger quantities can be subject to regulatory control. This restriction fails 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 with a continuing basis.
The lithium-polymer differentiates itself from conventional battery systems in the type of electrolyte used. The first design, going back on the 1970s, relies on 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 groups of atoms). The polymer electrolyte replaces the standard porous separator, which can be soaked with electrolyte.
The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring less than one millimeter (.039 inches), equipment designers are still to their own imagination in terms of form, shape and size.
Unfortunately, the dry lithium-polymer is affected with poor conductivity. The inner resistance is too high and cannot provide you with the current bursts required 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 increases the conductivity, a requirement that is certainly unsuitable for portable applications.
To compromise, some gelled electrolyte has been added. The commercial cells use a separator/ electrolyte membrane prepared from your same traditional porous polyethylene or polypropylene separator full of a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are extremely similar in chemistry and materials to their liquid electrolyte counter parts.
Lithium-ion-polymer has not yet 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 – in reality, the capability is slightly less than that of the conventional lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, including batteries for a credit card as well as other such applications.
Suprisingly low profile – batteries resembling the profile of a charge card are feasible.
Flexible form factor – manufacturers will not be bound by standard cell formats. With high volume, any reasonable size could be produced economically.
Lightweight – gelled electrolytes enable simplified packaging by reducing the metal shell.
Improved safety – more immune to overcharge; less possibility of electrolyte leakage.
Lower energy density and decreased cycle count compared to lithium-ion.
Costly to manufacture.
No standard sizes. Most cells are produced 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, “Just how much lithium within a battery am I allowed to bring aboard?” We differentiate between two battery types: Lithium metal and lithium-ion.
Most lithium metal batteries are non-rechargeable and so are used 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 no more than 25 grams can be carried in carry-on baggage if individually protected to avoid short circuits and are confined to two spare batteries per person.
How do I understand the 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 really must be considered. For the lithium-ion cell, this can be calculated at .three times the rated capacity (in ampere-hours).
Example: A 2Ah 18650 Li-ion cell has .6 grams of lithium content. On the typical 60 Wh laptop battery with 8 cells (4 in series and two in parallel), this adds up to 4.8g. To remain beneath the 8-gram UN limit, the Outdoor Power Equipment battery packs you may bring is 96 Wh. This pack could include 2.2Ah cells within a 12 cells arrangement (4s3p). In the event the 2.4Ah cell were utilized instead, the pack will have to be limited 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 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 volume of cells within a pack determine the lithium content.
Exception is given to packs that have lower 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 probably be required. Each package must be marked which it contains lithium batteries.
All lithium-ion batteries needs to be tested in accordance with specifications detailed in UN 3090 irrespective of lithium content (UN manual of Tests and Criteria, Part III, subsection 38.3). This precaution safeguards versus the shipment of flawed batteries.
Cells & batteries needs to be separated to prevent short-circuiting and packaged in strong boxes.