Small but not small button battery -Lithium - Ion Battery Equipment
Since its flat and round shape is very like a button, it is named as a button battery (button battery or button cell), and its flat design and metallic luster are similar to coins, so it is also called a coin battery. It is often used for power supply in watches, also known as watch battery.
Button batteries of different sizes
There are not many kinds of button batteries we often use, but there are many models and styles in the big family of button batteries, and their functions and characteristics are also different.
Button batteries are widely used internationally, so there are national standard models to regulate them. That is to say, button batteries purchased in different domestic and foreign markets can be universal as long as they have the same model. The model of button battery is generally marked on the positive pole of the battery.
The model of button battery has several important parts: the first number may represent several batteries connected in series, the first letter of a single battery represents the chemical composition of the battery, the next letter represents the shape of the battery, and the button battery is mostly circular in appearance, which is indicated by R. The last number is the size code, which will be explained separately here.
The International Electrotechnical Commission (IEC) has adopted two sets of methods for battery size numbering. In the early stage, the numbering method was digital serial number. Most of the last digits in the battery model were serial number. Now the new number has been stopped, but the old number can still be used normally.
Most of the new numbering methods are 4-digit numbers. The first two digits represent the diameter of the battery, in millimetres, and the last two digits represent the thickness of the battery, in millimetres. For example, the 4-digit code 2032 of the CR2032 battery means that the diameter of the battery is about 20 mm, and the thickness is about 3.2 mm. This code number is long, but it is easy to distinguish. It can be found that changing the old code to size can also become a new code.
The button battery is composed of positive electrode, negative electrode and electrolyte. The outer surface is usually made of stainless steel and used as the positive electrode. The negative electrode is a stainless steel round cover. There is a sealing ring between the positive electrode and the negative electrode. The sealing ring is made of nylon. In addition to insulation, the sealing ring can also prevent the leakage of electrolyte. It should be noted that unlike the common No. 5 battery, the protruding side of the button battery is the negative pole, while the flat side is the positive pole.
The button battery mainly includes primary battery and secondary battery. The primary battery is divided into lithium battery, alkaline battery, silver oxide battery and zinc-air battery according to the internal materials. These batteries can only be used once and cannot be recharged.
In addition, button batteries also have secondary batteries. The common ones are nickel-metal hydride batteries. The positive material is hydrogen storage alloy, the negative material is nickel oxide, and the electrolyte is alkaline metal hydroxide aqueous solution.
Button battery structure description
The principle of button battery with the same internal material is basically the same as that of other types of battery, and the voltage of the battery is basically the same. The nominal voltage of alkaline battery is 1.5V, mercury battery is 1.35V, alkaline zinc-air battery is 1.4V, silver oxide battery is 1.55V, and nickel hydrogen battery is 1.2V.
Because of its small size, button battery has some characteristics that other batteries do not have, which is also a reason for its advantages and disadvantages. Its compact size is much smaller than that of the No. 5 battery, but its energy supply is also much less than that of the large-volume battery, so it can be used in places where the power is small but the use space is very limited, especially in cardiac pacemakers and electronic hearing aids, which can also provide very long battery life.