Button batteries, also known as coin batteries, are batteries that are shaped like small buttons. Generally, they have a larger diameter and a thinner thickness. Button batteries are classified based on their appearance, and other battery classifications include cylindrical batteries, square batteries, and irregular batteries.
Button batteries typically come in two types: rechargeable and non-rechargeable. Rechargeable button batteries include rechargeable lithium-ion coin batteries and rechargeable lithium-ion coin batteries. Non-rechargeable button batteries include lithium manganese coin batteries and alkaline zinc-manganese coin batteries. The letters preceding the model name of button batteries represent the type of battery, while the numbers represent the dimensions. The first two digits represent the diameter, and the last two digits represent the thickness.
Button batteries have been widely used in various mini electronic products due to their small size. They are commonly used as backup power sources for various electronic products, such as computer motherboards, electronic watches, electronic dictionaries, electronic scales, remote controls, electric toys, pacemakers, electronic hearing aids, counters, cameras, etc. Button batteries are also classified into chemical batteries and physical batteries, with chemical batteries being the most commonly used.
They are composed of an anode (positive electrode), cathode (negative electrode), and electrolyte. Their appearance is made of stainless steel material and serves as the positive electrode, while the negative electrode is a round stainless steel cover. There is a sealing ring insulation between the positive and negative electrodes, and the sealing ring is made of nylon. In addition to insulation, the sealing ring can also prevent electrolyte leakage. There are many types of button batteries, most of which are named after the materials used, such as silver oxide batteries, lithium batteries, alkaline manganese batteries, etc.
In alkaline batteries that use zinc electrodes, silver oxide batteries, and zinc-air batteries, the zinc in the negative electrode reacts with the components in the electrolyte, leading to corrosion and consumption. This not only reduces the available capacity of the battery but may also generate hydrogen gas, causing an increase in internal pressure and expansion in sealed batteries. To suppress these effects, a small amount of mercury is usually applied to the surface of zinc. However, this also leads to mercury pollution from discarded batteries. Although mercury-free button batteries are already on the market, they have not yet become widely used due to technological or patent reasons. Button batteries are not included in the mercury ban for general dry batteries and still allow for a small amount of mercury. Proper recycling as directed by environmental agencies must be strictly adhered to.