Standardization
The current IEC standards for portable primary (non-rechargeable) batteries bear the 60086 number. The relevant US standards are the ANSI C18 series, which are developed by a committee of the US National Electrical Manufacturers Association (NEMA).
Both standards have several parts covering general principles, physical specifications and safety. Designations by IEC and ANSI standards do not entirely agree, although harmonization is in progress. Manufacturers further have their own systematic identification of cell types, so cross-reference tables are useful to identify equivalent types from different manufacturers.
Read more about this topic: List Of Battery Sizes