A clock battery or button cell is a small squiggly cylindrical single cell battery typically 5 to 25 mm in diameter (0.197 to 0.984 in) and 1 to 6 mm (0.039- 0.236 in) high - like buttons on clothing, hence its name. A metal can form the lower body and positive terminal of the cell. The isolated top cover is the negative terminal.
The button cells are used for powering small portable electronic devices such as watches, pocket calculators, artificial pacemakers, implanted heart defibrillators, car keyless transmitter entries, and hearing aids. A wider variant is usually called coin cell . Devices that use button cells are usually designed around cells that provide a long lifetime, usually more than a year in continuous use in watches. Most of the button cells have a low self-discharge and hold the charge for a long time when not in use. High-power devices such as hearing aids, where high-capacity essentials and low self-discharge are less so because cells will normally be used before they have time to dispose, can use air zinc cells that have a higher capacity for a given size, but dry during several weeks even if not used.
The button cells are single cells, usually single-use cells. Common anode material is zinc or lithium. Common cathode materials are manganese dioxide, silver oxide, carbon monofluoride, copper oxide or oxygen from the air. The mercury oxide button cells were formerly common, but are no longer available because of the toxicity and environmental effects of mercury.
Different chemical composition cells made in the same size are mechanically interchangeable. However, the composition may affect the life and voltage stability. Using the wrong cells can cause a short life or improper operation (for example, the measurement of light on the camera requires steady voltage, and silver cells are usually determined). Sometimes different cells of the same type and size and the capacity specified in milliampere-hours (mAh) are optimized for different loads using different electrolytes, so one can have a longer lifetime than the other if supplying relatively high current.
The button cells are very dangerous for small children. Swallowed key cells can cause severe internal burns and significant injury or death.
Video Button cell
Properti kimia sel
Alkaline batteries are made in button sizes similar to other types, but usually provide less capacity and less stable voltage than silver oxide or more expensive lithium cells. They are often sold as cheap watch batteries, and bought by people who do not know the difference.
The silver cells may have very stable output voltages until suddenly it drops very quickly at the end of life. It varies for individual types; one producer (Energizer) offers three silver oxide cells of the same size, 357-303, 357-303H and EPX76, with capacities ranging from 150 to 200 mAh, voltage characteristics ranging from gradual to fairly constant reduction, and some declare for channels low continuous with high pulse on demand, the other for photo usage.
Mercury batteries also supply steady voltage, but are now banned in many countries due to their toxicity and environmental impact.
Zinc-air batteries use air as a depolarizer and have a much higher capacity than other types, because they take air from the atmosphere. The cell has a seal against air that must be removed before use; the cells will then dry out in a few weeks, regardless of their use.
By comparison, the properties of multiple cells from one manufacturer with a different type with a diameter of 11.6 mm and a height of 5.4 mm are listed:
- Silver: capacity 200 mAh to end point 0.9 V, internal resistance 5-15Ã, ohm, weight 2.3 g
- Bases (manganese dioxide): 150 mAh (0.9), 3-9 ohms, 2.4 g
- Mercury: 200 mAh, 2.6 g
- Zinc-air: 620 mAh, 1.9 g
Checking the datasheets for the manufacturer's range may indicate a high capacity alkaline cell with a capacity as high as one of the lower-capacity silver types; or a specific silver cell with twice the capacity of some specific alkaline cells. If the powered equipment requires a relatively high voltage (eg 1.3 V) to operate properly, silver cells with flat discharge characteristics will provide longer service than alkaline cells - even if it has the same determined capacity in mAh to the end point 0 , 9 V. If some devices appear to "eat" the battery after the original source provided by the manufacturer is replaced, it may be useful to check the device requirements and the characteristics of the replacement battery. For digital calipers, in particular, some are specified to require at least 1.25 V to operate, others are 1.38 V.
In some ways size is the most important property of the button cell: different chemical cells up to a certain level can be interchanged. In practice only sufficiently similar voltage cells are made in a given size; there is no mechanically convertible lithium "CR1154" 3 V battery with 1.5 V silver or alkaline size of 1154 cells. The use of batteries with significantly higher voltages than equipment is designed to cause permanent damage, while the use of right-tension cells but inappropriate characteristics may cause short battery life or failure to operate the equipment.
Maps Button cell
Set type
International standard IEC 60086-3 defines an alphanumeric coding system for "Watch Battery". Manufacturers often have their own naming systems; for example, a cell called LR1154 with an IEC standard named AG13, LR44, 357, A76, and other names by different manufacturers. IEC standards and some others encode case sizes so that the numerical part of this code is uniquely determined by case size; other codes do not encode the size directly.
Examples of batteries that comply with IEC standards are CR2032, SR516, and LR1154, where letters and numbers indicate the following characteristics.
Electrochemical System
The first letter in the IEC standard system identifies the chemical composition of the battery, which also implies a nominal voltage:
For stable voltage types that fall sharply at the end of life (cliff-top voltage-versus-time graph), the end voltage is a value on the "cliff-edge", after which the voltage drops very quickly. For a type that loses voltage gradually (a gradient of slope, without a cliff edge) the end point is the outside voltage which further discharge will cause damage to the battery or a powered device, typically 1.0 or 0.9 V.
General names are more conventional than uniquely descriptive; For example, cells though referred to as silver [oxide] cells rather than base , actually have an alkali electrolyte.
L , S , and C current cell types are the most commonly used types in quartz watches, calculators, small PDA devices, computer clocks , and blinky lights. Miniature zinc-air batteries - P type - are used in hearing aids and medical equipment.
The second letter, R , shows a round shape (cylindrical).
The standard only describes the primary battery. Recharge types made in the same size will carry different prefixes that are not given in the IEC standard, for example some of the button cells ML and LiR use rechargeable lithium technology.
Package size
The size of the button battery pack using the standard name is indicated by a 2-digit code representing a standard case size, or a 3 or 4 digit code representing the diameter and height of the cell. The first one or two digits encode the battery's outer diameter in whole millimeters, rounded down; the exact diameter is determined by the standard, and there is no ambiguity; eg any cell with the prefix 9 is 9.5 mm in diameter, no other values ​​between 9.0 and 9.9 are used. The last two digits are the overall height in a tenth of a millimeter.
Example:
- CR2032: lithium, diameter 20 mm, height 3.2 mm
- SR516: silver, 5.8 mm in diameter, 1.6 mm in height
- LR1154/SR1154: alkaline/silver, diameter 11.6 mm, height 5.4 mm. LR44/SR44 double-digit codes are often used for this size
Some coin cells, especially lithium, are available in versions to be soldered into circuits (usually for very low power semiconductor memory ICs with configuration information for devices, over the years), with different versions for vertical or horizontal mounting. The full nomenclature will have prefixes and suffixes to indicate specific terminal settings. For example, there are CR2032 plug-in and solder-in, plug-in and three-in-solder BR2330s other than CR2330s, and many rechargeables in 2032, 2330, and other sizes.
Sentence
After the package code, the following additional letters may optionally appear in a type designation to indicate the electrolyte used:
- P: potassium hydroxide electrolyte
- S: sodium hydroxide electrolyte
- No letter: organic electrolyte
- W: batteries meet all international standard requirements of IEC 60086-3 for watch batteries.
Other tagging marks
Regardless of the type code described in the previous section, note the battery should also be marked with
- the name or trademark of the manufacturer or supplier;
- polarity ();
- creation date.
Date code
Often a 2-letter code (sometimes on the side of the battery) where the first letter identifies the manufacturer and the second is the year of manufacture. As an example:
- YN - the letter N is the 14th letter in the alphabet - shows cells created in 2014.
There is no universal standard.
The creation date may be shortened to the last digit of the year, followed by a digit or letter indicating the month, where O, Y, and Z are used for October, November and December, respectively (e.g. 01, January 1990 or January 2000, = November 1999 or November 2009).
General manufacturer code
The code used by some manufacturers is AG (alkaline) or SG (silver) followed by the number, where 1 equals the standard 621, 2 to 726, 3 to 736, 4 to 626, 5 to 754, 6 to 920 or 921, 7 to 926 or 927, 8 to 1120 or 1121, 9 to 936, 10 to 1130 or 1131, 11 to 721, 12 to 1142 and 13 to 1154. those who are familiar with the chemical symbol for silver, Ag, this may indicate incorrectly that AG cells are silver.
General apps
Variable refill
In addition to single-use (disposable) button cells, rechargeable batteries in many of the same sizes are available, with a lower capacity than discardable cells. Disposable and rechargeable batteries are manufactured to fit the stand or with a solder label for a permanent connection. In equipment with battery holder, disposable or rechargeable batteries may be used, if the tension is compatible.
Common use for small rechargeable batteries (in coins or other formats) is to reserve the equipment arrangements that normally permanently use a power source, in the event of a power failure. For example, many central controllers store operating times and similar information in volatile memory, lost in case of power failure. It is not unusual for such a system to insert a spare battery, either that can be disposed in the cradle (very low current drainage and long life) or soldered refills.
The rechargeable NiCd key cells are often components of an old computer backup battery; non-rechargeable lithium button cells with a lifespan of several years are used in subsequent equipment.
Rechargeable batteries usually have the same dimensionless numeric codes with different letters; so the CR2032 is a disposable battery while ML2032, VL2032 and LIR2032 are refilled in accordance with the same holder if not equipped with solder label. Mechanically possible, though dangerous, to adjust disposable batteries in a cradle intended to be refilled; the holder is installed in a piece of equipment accessible only to service personnel in such cases.
Health issues
In large metropolitan areas small children are directly affected by the improper disposal of button cell battery types, with Auckland in NZ getting about 20 cases per year requiring hospitalization.
Young children tend to swallow the button cells, which are visually similar to candy, often causing death. In Greater Manchester, Britain, with a population of 2.7 million, has had two children between 12 months and six years who have died and five suffered life-altering injuries in the 18 months leading up to October 2014. Coin cells have a diameter of 20 mm or a larger cause of injury the most serious, even if not destroyed.
Mercury or cadmium
Some key cells contain mercury or cadmium, which is toxic. In early 2013, the European Parliament Environmental Committee voted to ban the export and import of mercury-containing products such as button cells and other batteries to be charged starting in 2020.
Lithium
Lithium cells, if swallowed, are very dangerous. The damage is caused, not by the charge of the battery, but by the electric current it creates, which causes sodium hydroxide (caustic soda) to build and burn through the esophagus and into the main blood vessels, which can cause fatal bleeding. The University of Manchester Central Trust Hospital warned that "many doctors are unaware that this can cause harm".
Counterfeit
There are many fake batteries of all types, including button cells, branded and packaged as products of reliable manufacturers. They are often sold for a fraction of the original wholesale battery price, although higher prices are not a guarantee of legitimacy. Many are badly packed, for example with simple blisters mounted on the cardboard backing where the original is packed better. Leading producer Maxell says, without specifying, that they are aware of counterfeit goods. They warn that they can cause injury and damage, and ask them to be contacted about fake. In many forums on Amazon and similar e-commerce sites, there are persistent and repeated reports of failed batteries after a very short time; Consumer reviews typically show excellent proportion of reviews ("arriving very quickly... functioning OK... very cheap"), but a large number of long-term reviews provide the lowest rating. This natural review is not considered a reliable source, but this report is widespread.
One company has investigated Sony-branded watches and coin batteries specifically, and reports that the most fake ones include CR2032, CR2025, CR2016, SR626SW (377), and SR621SW (364). They show pictures of the original and fake battery compositions wrapped in cards on their websites; they are very similar.
See also
- List of battery sizes
- List of battery types
- Battery recycling
- Artificial pacemaker
- Implantable cardioverter-defibrillator
References
Note
External links
Media related to Button cells in Wikimedia Commons
- Coin cell reference table
- Watch a cross-reference table of batteries
- "IEC 60086-2 Main battery - Part 2: Physical and electrical specifications" (PDF) . Ã, (including debit characteristics)
- "DIRECTIVE 2006/66/EC FROM THE EUROPEAN PARLIAMENT AND COUNCIL". Ã, (407Ã, Kb) 6 September 2006 (battery recycling and disposal)
Source of the article : Wikipedia
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