Lithium cells Coin-shaped cells are thin compared to their diameter.
Polarity is usually stamped on the metal casing. The IEC prefix "CR" denotes lithium manganese dioxide chemistry. Since LiMnO2 cells produce 3 volts there are no widely available alternative chemistries for a lithium coin battery. The "BR" prefix indicates a round lithium/carbon monofluoride cell. See
lithium battery for discussion of the different performance characteristics. One LiMnO2 cell can replace two alkaline or silver-oxide cells. IEC designation numbers indicate the physical dimensions of the cylindrical cell. Cells less than one centimeter in height are assigned three- or four-digit numbers, where the last two digits are the height in tenths of millimeters, and the preceding digit(s) are the diameter in millimeters, rounded down (see table
here). Taller cells are assigned five-digit numbers, where the first two digits are the diameter in millimeters, followed by the last three digits indicating the height in tenths of millimeters. All these lithium cells are rated nominally 3 volts (on-load), with open-circuit voltage about 3.6 volts. Manufacturers may have their own part numbers for IEC standard size cells. The capacity listed is for a constant resistance discharge down to 2.0 volts per cell.
Silver oxide and alkaline cells In the following table, sizes are shown for the silver-oxide IEC number; types and capacity are identified as "(L)" for alkaline, "(M)" for mercury (no longer manufactured), and "(S)" for silver-oxide. Some sizes may be interchangeably used in battery holders. For example, the 189/389 cell is 3.1 mm high and was designated 1131, while the 190/390 size is 3.0 mm high and was designated 1130, but a battery holder will accept either size.
Zinc air cells (hearing aid) Miniature zinc-air batteries are button cells that use oxygen in air as a reactant and have very high capacity for their size. Each cell needs around 1 cm3 of air per minute at a 10 mA discharge rate. These cells are commonly used in hearing aids. A sealing tab keeps air out of the cell in storage; a few weeks after breaking the seal the electrolyte will dry out and the battery becomes unusable, regardless of use. Nominal voltage on discharge is 1.2 V. ==Lithium-ion batteries (rechargeable)==