Button battery introduction

Button cell battery [1], also known as watch battery [2] or coin battery, is one of the shape classification of batteries, such as buttons, buttons, coins, Small battery such as bean. Button-type batteries come in a variety of styles, from large to small in diameter and thin and thick in thickness.
Most button-type batteries are primary batteries (non-rechargeable batteries, also known as primary batteries), which are also dry batteries, but are generally used in large, long, large, long, first, second, third, and fourth sizes. Dry batteries are significantly different in appearance.
The button type battery has a smaller power supply capacity and a supplyable power than a general dry battery, and is mainly used in a small portable device that is inconvenient to use an external power source, such as a computer, a watch, an electronic thermometer, and the like. In addition, it is also used in backup batteries in various computer-type devices to maintain internal clock and memory contents when not powered, such as batteries that maintain BIOS memory and clock.
According to the composition, common types of button-type batteries include lithium batteries, alkaline batteries, silver oxide batteries, and zinc-air batteries. Early mercury batteries have been banned due to environmental pollution problems. However, in addition to lithium batteries that start with BR and CR, other button batteries may still contain a small amount of mercury (ie, mercury). Although in recent years, manufacturers have developed alkaline batteries and silver oxide batteries that do not contain mercury, due to technical and patent reasons, the button batteries still allow a small amount of mercury in the current state of the dry battery mercury ban. Therefore, for used button batteries, they should still be placed in the designated recycling space. Do not discard or mix garbage to affect the environment.
A button-type rechargeable battery (also known as a secondary battery) is usually built into the product, such as a rechargeable button battery built into a small Bluetooth headset. The rechargeable battery and charger are not sold in general stores.
The international standard models of button batteries, such as LR44, CR2032, etc., have the following meanings:
If the number ** bit has a number, it means that the internal is a series connection of several battery cells. For example, the inside of 4LR44 is composed of 4 LR44 series.
The next letter is the chemical composition of the battery. The chemical composition of the button battery is as follows.

	Code	Battery composition type	negative electrode	Electrolyte	positive electrode	Q
Primary battery	B	Lithium fluorinated carbon battery	lithium	Non-aqueous organic electrolyte	Carbon monofluoride	3.0
	C	Lithium manganese dioxide battery	lithium	Non-aqueous organic electrolyte	manganese dioxide	3.0
	G	Lithium oxide copper battery	lithium	Non-aqueous organic electrolyte	Copper oxide	1.5
	L	Alkaline battery	Zinc	Alkali metal hydroxide aqueous solution	manganese dioxide	1.5
	M	Mercury battery Disabled, the current standard has removed this class	Zinc	Zinc oxide solution	Mercury oxide	1.35
	P	Alkaline zinc air battery	Zinc	Alkali metal hydroxide aqueous solution	oxygen	1.4
	S	Silver oxide battery	Zinc	Alkali metal hydroxide aqueous solution	Silver oxide	1.55
Secondary battery	H	NiMH batteries	Nickel oxide	Alkali metal hydroxide aqueous solution	Hydrogen storage alloy	1.2

The next letter represents the shape of the battery, and the button battery is generally circular and is represented by R.
Finally, the code for the size. The International Electrotechnical Commission (IEC) battery size number has two sets of methods. In the early stage, the serial number of 1~2 digits was set under the English code of each shape, for example, LR44. This method has been discontinued, but the old number can still be used. The new method is to encode according to the approximate number of the battery size, the number of bits is long, for example, the CR2032 has a diameter of about 20 mm and a thickness of about 3.2 mm. However, for accurate size specifications, the relevant international standards and manufacturer specifications should be consulted. Sometimes the old and new numbers will coexist, for example, the old number R54 in the table below is equal to the new number R1130.
The actual values ​​represented by some common size codes, as well as the common numbers, can be found in the following tables.
Alkaline batteries and button-type silver oxide battery <br> alkaline batteries (code L), a nominal voltage of 1.5 V.
Silver oxide battery (code S), nominal voltage 1.55 V.
The two battery voltages are very close and can be used in principle, but due to different electrical characteristics, sometimes some appliances use a suitable battery to have a better effect. For example, a general watch uses a silver oxide battery.

Shape size code	Diameter (max.)	Thickness (max.)	Alkaline battery number	Silver oxide battery number	Other number
R41	7.9	3.6	LR41	SR41	392, 384
R43	11.6	4.2	LR43	SR43	386
R44	11.6	5.4	LR44	SR44	A76, G13
R48	7.9	5.4	LR48	SR48
R54 R1130	11.6	3.05	LR54 LR1130	SR54 SR1130	G10, 189
R55 R1120	11.6	2.05		SR55 SR1120
R70	5.8	3.6

Button-type lithium battery <br> The common disposable lithium battery is a lithium-manganese battery (code C) with a nominal voltage of 3 V.
Another less common disposable lithium battery is a lithium-carbon fluoride battery (code B) with a nominal voltage of 3 V.
Lithium battery size numbers are usually numbered using the new IEC method. The first two digits are the diameter (in mm) and the last two digits are the thickness (in 0.1 mm), which is close to the number. For example, the CR2032 is roughly 20 mm in diameter and 3.2 mm thick.
Take the CR lithium manganese battery as an example. The battery models are:
CR927
CR1025
CR1216, CR1220
CR1616, CR1620, CR1632
CR2012, CR2016, CR2025, CR2032
CR2320, CR2330, CR2354
CR2450, CR2477
CR3032