As a backup power, button battery is named after their coin shape. People often distinguish these batteries with their rated voltage. For example, 3V coin cell refers to CR series battery whereas 1.5V button cell ordinarily is Ag series battery.
Button batteries can be divided into rechargeable and non-rechargeable batteries. They have the following categories as per different voltages.
Non-rechargeable button batteries: 3V lithium manganese series (CR series), 1.5V alkaline button cell (LR series, including AG series), 1.55V zinc-silver oxide SR series and 1.4V zinc air ZA series and 1.35V mercury batteries.
Rechargeable button battery: 3.6V lithium-ion LIR series and 3V lithium-ion ML& VL series.
At present, CR series and AG series are most commonly used.
CR series battery is 3V lithium manganese button cell, e.g. CR2025 and CR2025. Rated voltage of CR button cell is 3V and cutoff voltage 2V with 0.1mA-0.2mA typical working current. This battery is mostly used on electronic dictionary, main board CMOS, watch and other electronic products.
AG series battery, attached to alkaline LR series, is made up of 14 products with 1.5V voltage. This battery is suitable for mA discharge requirement and used on calculator, electronic toy, hearing aid and watch.
Among non-rechargeable batteries, 1.55V zinc-silver oxide battery plays a vital role. This battery, represented by SR, is characterized with high capacity, stable discharge voltage and good storage performance. Discharge curve of zinc-silver oxide battery is stable with 90% part above 1.45V. Dimension of this battery can be designed to be the same with that of alkaline button cells.
Voltage of 3.6V LIR series rechargeable batteries is the highest among coin cells, almost three times higher than that of same model Ni-MH battery. Voltage of rechargeable ML and LV series battery is 3V. Rechargeable button cells are applicable to various electronic products.
There are also Ni-MH button batteries in practical use, but they are just abnormal shape batteries.
In overlapping way, single button cell can be made to other battery models of different voltage, e.g. 6V F22, F22, 11A, 26A and 476A, 9V 6F22, 10A and 25A, 8.4V 120H7D, and 12V 23A and 27A.
