Button cell

A watch array or button corpuscle is a baby individual corpuscle array shaped as a broad butt about 5 to 12 mm in bore and 1 to 6 mm high—like a button on a garment, appropriately the name. Button beef are acclimated to ability baby carriageable electronics accessories such as wrist watches, abridged calculators, and audition aids. Some beef beyond than the ambit aloft are aswell alleged button cells, but are beneath frequently used. Lithium beef are about agnate but somewhat larger; they tend to be alleged either lithium beef or batteries or bread beef rather than button cells.

Devices application button beef are usually advised to use a corpuscle giving a continued account life, about able-bodied over a year in connected use in a wristwatch. Most button beef accept low self-discharge and authority their allegation for a continued time if not used. Higher-power accessories such as audition aids, area top accommodation is important and low self-discharge beneath so as the corpuscle will usually be acclimated up afore it has time to discharge, may use zinc-air beef which accept abundant college accommodation for a accustomed size, but acquittal over a few weeks even if not used.

Button beef are individual cells, usually disposable primary cells. Accepted anode abstracts are zinc or lithium. Accepted cathode abstracts are manganese dioxide, argent oxide, carbon monofluoride, cupric oxide or oxygen from the air. Mercuric oxide button beef were aforetime common, but are no best accessible due to the toxicity and ecology hazard of mercury.

Cells accept a metal can basic the basal body, with a annular cloistral top cap. The can is the absolute and the top the abrogating terminal.

Cells of altered actinic agreement fabricated in the aforementioned admeasurement are mechanically interchangeable. However, the agreement can affect account activity and voltage stability. Application the amiss corpuscle may advance to abbreviate activity or abnormal operation (for example, ablaze metering on a camera requires a abiding voltage, and argent beef are usually specified). Sometimes altered beef of the aforementioned blazon and admeasurement and defined accommodation in mAh are optimised for altered endless by application altered electrolytes, so that one may accept best account life, than the added if bartering a almost top current.

Properties of different types

Silver beef may accept actual abiding achievement voltage until it al of a sudden drops actual rapidly at end of life. This varies for alone types; one architect (Energizer) offers 3 argent oxide beef of the aforementioned size, 357-303, 357-303H,and EPX76, with capacities alignment from 150 to 200 mAh, voltage characteristics alignment from gradually abbreviation to adequately constant, and some declared to be for connected low cesspool with top beating on demand, others for photo use.

Mercury batteries aswell accumulation a abiding voltage, but are now banned in abounding countries due to their toxicity and ecology impact.

Alkaline batteries are fabricated in the aforementioned button sizes as added types, but about accommodate beneath accommodation and beneath abiding voltage (it drops gradually in use) than added cher argent oxide or lithium cells. They are generally awash as bargain watch batteries to, and sometimes by, humans who do not apperceive the difference.1

Zinc-air batteries use air as the depolarizer and accept abundant college accommodation than added types (they use air from the atmosphere which does not charge to be supplied in the battery). A allowance is removed afore use to acquiesce air to access the cell; the corpuscle will again self-discharge in a few weeks even if not acclimated up.

For comparison, a corpuscle of bore 11.6 mm and acme 5.4 mm from one acclaimed architect has the afterward properties.2 In abounding cases there are several batteries of the aforementioned allure and admeasurement with altered capacities and properties; abstracts listed are alone indicative.

Silver: accommodation 200 mAh to an end-point of 0.9 V, centralized attrition 5–15 ohms, weight 2.3 g

Acrid (manganese dioxide): 150 mAh (0.9), 3-9 ohms, 2.4 g

Mercury 200mAh, 2.6 g

Zinc-air 620 mAh, 1.9 g

Examining datasheets for a manufacturer's range2 may acquisition a high-capacity acrid corpuscle with a accommodation as top as one of the lower-capacity argent types; or a accurate argent corpuscle with alert the accommodation of some accurate acrid cell. If the powered accessories acute a almost top voltage (e.g., 1.3V) to accomplish correctly, a argent corpuscle with a collapsed acquittal appropriate will accord abundant best account than an acrid cell—even if it has the aforementioned defined accommodation in mAh to an end-point of 0.9V. If some accessory seems to "eat up" batteries afterwards the aboriginal supplied by the architect is replaced, it may be advantageous to analysis the device's requirements and the backup battery's characteristics. For agenda calipers, in particular, some are defined to crave at atomic 1.25V to operate, others 1.38V.34

Datasheets for some cheaper cells, decidedly alkaline, are not available, so it is not accessible to say whether capacities are about the aforementioned as for accurate types.5 Discussions on web forums advance that they can be actual poor.6

In some means the admeasurement is the a lot of important acreage of a button cell: beef of altered allure are to a ample admeasurement interchangeable. In convenance alone beef of adequately agnate voltages are fabricated in any accustomed size; there is no "CR1154" 3V lithium array mechanically changeable with a 1.5V argent or acrid admeasurement 1154 cell. Use of a array of decidedly college voltage than accessories is advised for can could cause abiding damage, but use of a corpuscle of the appropriate voltage but clashing characteristics can alone advance to abbreviate array activity or abortion to accomplish equipment.

Type designation

International accepted IEC 60086-3 defines an alphanumeric coding arrangement for "Watch batteries". Manufacturers generally accept their own allotment system; for example, the corpuscle alleged LR1154 by IEC accepted is alleged AG13, LR44, 357, A76, and added names by altered manufacturers. The IEC accepted and some others encode the case admeasurement so that the numeric allotment of the cipher is abnormally bent by the case size; added codes do not encode admeasurement directly.

Examples of batteries befitting to the IEC accepted are CR2032, SR516, and LR1154, area the belletrist and numbers announce the afterward characteristics.

edit Electrochemical system

The aboriginal letter identifies the actinic agreement of the battery, which aswell implies a nominal voltage:

Letter

code Common

name Positive

electrode Electrolyte Negative

electrode Nominal

voltage End-point

voltage

L Alkaline Manganese dioxide Alkali Zinc 1.5 1.0

S Silver Silver oxide Alkali Zinc 1.55 1.2

P Zinc-air Oxygen Alkali Zinc 1.4 1.2

C Lithium Manganese dioxide Organic Lithium 3 2.0

B Carbon monofluoride Organic Lithium 3 2.0

G Copper oxide Organic Lithium 1.5 1.2

M,N(withdrawn) Mercury Mercuric oxide Alkaline Zinc 1.35/1.40 1.1

For types with abiding voltage falling precipitously at end-of-life (cliff-top voltage-versus-time graph), the end-voltage is the amount at the "cliff-edge", afterwards which it drops acutely rapidly. For types which lose voltage gradually (slope graph, no cliff-edge) the end-point is the voltage above which it is accounted that accessories will not plan properly, about 1.0 or 0.9V.

Common names are accepted rather than abnormally descriptive; for example, a corpuscle alleged a "silver oxide cell" rather than "alkaline" in fact has an acrid electrolyte.

"L", "S", and "C" blazon beef are today the a lot of commonly-used types in quartz watches, calculators, baby PDA devices, computer clocks, and acerb lights. Miniature zinc-air batteries blazon "P" are acclimated in audition aids and medical instruments.

edit Amalgamation size

Several sizes of button and bread corpuscle with 2 9v batteries as a admeasurement comparison.

Package admeasurement of button batteries application accepted names is adumbrated by a two-digit cipher apery a accepted case size, or a three- or four-digit cipher apery the corpuscle bore and height. The aboriginal one or two digits encode the alien bore of the array in accomplished millimeters, angled down; exact diameters are defined by the standard, and there is no ambiguity, e.g., any corpuscle with an antecedent "9" is 9.5 mm in diameter, no added amount amid 9.0 and 9.9 is used. The endure two digits are the all-embracing acme in tenths of a millimeter.

Diameter codes (1st 1 or 2 digits) Number

code Nominal

diameter (mm) Tolerance

4 4.8 ±0.15 mm

5 5.8 ±0.15 mm

6 6.8 ±0.15 mm

7 7.9 ±0.15 mm

9 9.5 ±0.15 mm

10 10.0 ±0.20 mm

11 11.6 ±0.20 mm

12 12.5 ±0.25 mm

16 16 ±0.25 mm

20 20 ±0.25 mm

23 23 ±0.50 mm

24 24.5 ±0.50mm

Examples:

CR2032: lithium, 20 mm diameter, 3.2 mm height

SR516: silver, 5.8 mm diameter, 1.6 mm height

LR1154/SR1154: alkaline/silver, 11.6 mm diameter, 5.4 mm height. The two-digit codes LR44/SR44 are generally acclimated for this size

edit Letter suffix

After the amalgamation code, the afterward added belletrist may optionally arise in the blazon appellation to announce the electrolyte used:

P: potassium hydroxide electrolyte

S: sodium hydroxide electrolyte

no letter: amoebic electrolyte

Also:

W; the array complies with all the requirements of the all-embracing IEC 60086-3 7 accepted for watch batteries.

Type CR2032 watch array (lithium anode, 3 V, 20.0 mm × 3.2 mm)

Leaked and breakable button cell

edit Added amalgamation markings

Apart from the blazon cipher declared in the above-mentioned section, watch batteries should aswell be apparent with

the name or brand of the architect or supplier;

the polarity (+);

the date of manufacturing.

The accomplishment date can be abbreviated to the endure chiffre of the year, followed by a chiffre or letter advertence the month, area O, Y, and Z are acclimated for October, November and December, appropriately (e.g., 01 = January 1990 or January 2000, 9Y = November 1999).

edit Common architect code

A cipher acclimated by some manufacturers is AG (alkaline) or SG (silver) followed by a number, area 1 equates to accepted 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. To those accustomed with the actinic attribute for silver, "Ag", this may advance afield that AG beef are silver.

Common applications

Electric wristwatches, both agenda and analogue.

Calculators.

Hearing aids.

Some limited controls, abnormally for keyless entry.

Backup ability for claimed computer absolute time clocks and BIOS agreement data.

Small PDA devices.

Assorted cyberbanking toys (like tamagotchi, Pokémon Pikachu or a Pokéwalker and added assorted Virtual Pet devices.)

Laser pointers.

Small LED flashlights.

Battery-operated children's books.

Glucometers.

Security tokens.

Cyclocomputers.

Red dot architect and cyberbanking spotting scopes.

Manual cameras with ablaze meters.

LED throwies.

Assorted video bold cartridges or anamnesis cards area battery-powered RAM is acclimated to abundance data.

PCMCIA changeless RAM anamnesis cards.

Solar/Electric Candles.

LED Bicycle arch and/or appendage lighting

agenda thermometers

Rechargeable variants

Most button corpuscle batteries are not rechargeable due to the inferior accommodation and/or top self-discharge amount of rechargeable batteries. There are a few rechargeable button corpuscle batteries, such as lithium-ion rechargeable batteries advised to alter CR-series lithium manganese dioxide batteries in accessories with almost top accepted burning or some accessories with solar panels which can be acclimated to accumulate the array answerable beneath assertive circumstances.

Rechargeable NiCd button beef were generally apparatus of the advancement array of earlier IBM PC compatibles as able-bodied as Amiga computers.