Lithium battery

Lithium batteries are disposable (primary) batteries that have lithium metal or lithium compounds as an anode.

They stand apart from other batteries in their high charge density (long life) and high cost per unit. Depending on the design and chemical compounds used, lithium cells can produce voltages from 1.5 V (comparable to a zincâ€"carbon or alkaline battery) to about 3.7 V.

By comparison, lithium-ion batteries are rechargeable batteries in which lithium ions move between the anode and the cathode, using an intercalated lithium compound as the electrode material instead of the metallic lithium used in lithium batteries.

Lithium batteries are widely used in products such as portable consumer electronic devices.

History

Description

The term "lithium battery" refers to a family of different chemistries, comprising many types of cathodes and electrolytes. The battery requires from 0.15 to 0.3 kg of lithium per kWh.

The most common type of lithium cell used in consumer applications uses metallic lithium as anode and manganese dioxide as cathode, with a salt of lithium dissolved in an organic solvent.

Another type of lithium cell having a large energy density is the lithium-thionyl chloride cell. Lithium-thionyl chloride batteries are generally not sold to the consumer market, and find more use in commercial/industrial applications, or are installed into devices where the consumer does not replace them. The cell contains a liquid mixture of thionyl chloride (SOCl₂) and lithium tetrachloroaluminate (LiAlCl
4), which act as the cathode and electrolyte, respectively. A porous carbon material serves as a cathode current collector which receives electrons from the external circuit. Lithium-thionyl chloride batteries are well suited to extremely low-current applications where long life is necessary, such as wireless alarm systems.

Chemistries

The liquid organic electrolyte is a solution of an ion-forming inorganic lithium compound in a mixture of a high-permittivity solvent (propylene carbonate) and a low-viscosity solvent (dimethoxyethane).

Applications

Lithium batteries find application in many long-life, critical devices, such as pacemakers and other implantable electronic medical devices. These devices use specialized lithium-iodide batteries designed to last 15 or more years. But for other, less critical applications such as in toys, the lithium battery may actually outlast the device. In such cases, an expensive lithium battery may not be cost-effective.

Lithium batteries can be used in place of ordinary alkaline cells in many devices, such as clocks and cameras. Although they are more costly, lithium cells will provide much longer life, thereby minimizing battery replacement. However, attention must be given to the higher voltage developed by the lithium cells before using them as a drop-in replacement in devices that normally use ordinary zinc cells.

Lithium batteries also prove valuable in oceanographic applications. While lithium battery packs are considerably more expensive than standard oceanographic packs, they hold up to three times the capacity of alkaline packs. The high cost of servicing remote oceanographic instrumentation (usually by ships) often justifies this higher cost.

Sizes and formats

Small lithium batteries are very commonly used in small, portable electronic devices, such as PDAs, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOS, communication equipment and remote car locks. They are available in many shapes and sizes, with a common variety being the 3 volt "coin" type manganese variety, typically 20 mm in diameter and 1.6â€"4 mm thick.

The heavy electrical demands of many of these devices make lithium batteries a particularly attractive option. In particular, lithium batteries can easily support the brief, heavy current demands of devices such as digital cameras, and they maintain a higher voltage for a longer period than alkaline cells.

Popularity

Lithium primary batteries account for 28% of all primary battery sales in Japan but only 1% of all battery sales in Switzerland. In the EU only 0.5% of all battery sales including secondary types are lithium primaries.

Safety issues and regulation

The computer industry's drive to increase battery capacity can test the limits of sensitive components such as the membrane separator, a polyethylene or polypropylene film that is only 20-25 µm thick. The energy density of lithium batteries has more than doubled since they were introduced in 1991. When the battery is made to contain more material, the separator can undergo stress.

Ingestion and choking hazard

Button cell batteries are attractive to small children and often ingested. In the past 20 years, although there has not been an increase in the total number of button cell batteries ingested in a year, researchers have noted a 6.7-fold increase in the risk that an ingestion would result in a moderate or major complication.

The primary mechanism of injury with button battery ingestions is the generation of hydroxide ions at the anode. The hydroxide ions result in a chemical burn. Complications include oesophageal strictures, Tracheo-oesophageal fistulas, vocal cord paralysis, aorto-oesophageal fistulas, and death. The majority of ingestions are not witnessed; presentations are non-specific; battery voltage has increased; the 20 to 25 mm button battery size are more likely to become lodged at the cricopharyngeal junction; and severe tissue damage can occur in 2 hours. The 3 V, 20 mm lithium battery has been implicated in many of the complications from button battery ingestions by children less than 4 years of age. Button batteries can also cause significant necrotic injury when stuck in the nose or ears.

Rapid-discharge problems

Lithium batteries can provide extremely high currents and can discharge very rapidly when short-circuited. Although this is useful in applications where high currents are required, a too-rapid discharge of a lithium battery can result in overheating of the battery, rupture, and even explosion. Lithium-thionyl chloride batteries are particularly susceptible to this type of discharge. Consumer batteries usually incorporate overcurrent or thermal protection or vents to prevent explosion.

Air travel

From January 1, 2013 much stricter regulations for the carriage of Lithium batteries were introduced by IATA regarding the carriage of lithium batteries by air. They were adopted by the International Postal Union; however, some countries, e.g. the UK, have decided that they will not accept Lithium batteries unless they are included with the equipment they power.

Because of the above risks, shipping and carriage of lithium batteries is restricted in some situations, particularly transport of lithium batteries by air.

The United States Transportation Security Administration announced restrictions effective January 1, 2008 on lithium batteries in checked and carry-on luggage. The rules forbid lithium batteries not installed in a device from checked luggage and restrict them in carry-on luggage by total lithium content.

Australia Post prohibited transport of lithium batteries in air mail during 2010.

UK regulations for the transport of lithium batteries were amended by the National Chemical Emergency Centre in 2009.

In late 2009, at least some postal administrations restricted airmail shipping (including EMS) of lithium batteries, lithium-ion batteries and products containing these (such as laptops and cell phones). Among these countries are Hong Kong, USA and Japan.

Lithium batteries and methamphetamine labs

Unused lithium batteries provide a convenient source of lithium metal for use as a reducing agent in methamphetamine labs. Some jurisdictions have passed laws to restrict lithium battery sales or asked businesses to make voluntary restrictions in an attempt to help curb the creation of illegal meth labs. In 2004 Wal-Mart stores were reported to limit the sale of disposable lithium batteries to three packages in Missouri and four packages in other states.

Disposal

Regulations for disposal and recycling of batteries vary widely; local governments may have additional requirements over those of national regulations. In the United States, one manufacturer of lithium iron disulfide primary batteries advises that consumer quantities of used cells may be discarded in municipal waste, as the battery does not contain any substances controlled by US Federal regulations. Another manufacturer states that "button" size lithium batteries contain perchlorate, which is regulated as a hazardous waste in California; regulated quantities would not be found in typical consumer use of these cells.

See also

References

External links

• The 2009 amendments to the regulations regarding transport of Lithium Batteries
• Lithium Iron Phosphate Battery information
• Properties of non-rechargeable lithium batteries
• Brand Neutral Drawings of Lithium Batteries based on ANSI Specifications
• Lithium Thionyl Chloride Battery MSDS and supporting safety information
• Lithium Battery Fires Site offering free courses on how to control an in-flight fire

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