IEC 62133-1:2017 specifies requirements and tests for the safe operation of portable sealed secondary nickel cells and batteries containing alkaline electrolyte, under intended use and reasonably foreseeable misuse. This first edition cancels and replaces the second edition of IEC 62133 published in 2012. It constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 62133:2012: - separation of lithium systems into a separate Part 2; - inclusion of button cell requirements.