IEC 62660-3 specifies safety requirements and test procedures for secondary lithium-ion cells used in the propulsion of electric road vehicles, published by the International Electrotechnical Commission (IEC). It is Part 3 of the IEC 62660 series — complementing IEC 62660-1 (performance) and IEC 62660-2 (reliability and abuse testing) — and specifically addresses the safety behaviour of individual cells under conditions representative of use in a vehicle traction battery pack.
Published by: International Electrotechnical Commission (IEC)
Current edition: IEC 62660-3:2022 (2nd edition)
Companion standards: IEC 62660-1 (EV cell performance), IEC 62660-2 (EV cell abuse testing), ISO 12405-4 (pack-level testing)
Scope
IEC 62660-3 applies to secondary lithium-ion cells and cell blocks used for propulsion of battery electric vehicles (BEV) and hybrid electric vehicles (HEV/PHEV). The standard determines the basic safety performance of cells under intended use conditions and reasonably foreseeable misuse or incident, within the context of normal EV operation. It is explicitly scoped to cells within a battery pack and system where the BMS is assumed to manage the cells within the manufacturer’s defined voltage, current, and temperature limits. Transport and storage safety are outside the scope of IEC 62660-3 and are addressed by IEC 62281.
Key Requirements and Tests
IEC 62660-3 defines safety tests at the cell level including external short circuit (verifying safe response when cell terminals are short-circuited externally), overcharge (cell charged beyond its rated upper voltage limit), forced discharge / over-discharge (cell driven below minimum voltage by a series-string imbalance or system fault), crush (cell subjected to a compressive force simulating a collision), heating in an oven (thermal stability test), and nail penetration (a conductive nail is driven through the cell to create an internal short circuit — one of the most severe thermal abuse tests).
Pass/fail criteria require that cells do not catch fire or explode during or after any test. Electrolyte leakage is observed and recorded but may not constitute a failure in all tests. Each test specifies the initial state of charge, temperature, and rate of abuse application.
Relevance to Battery Engineering
IEC 62660-3 cell-level safety testing is a standard element of the qualification process for lithium-ion cells intended for automotive traction battery applications. For cell engineers, the nail penetration and overcharge tests in particular drive design decisions about separator technology, electrolyte formulation, electrode porosity, and safety feature integration such as current interrupt devices and positive temperature coefficient (PTC) elements. Vehicle manufacturers and tier-1 battery suppliers typically require IEC 62660-3 test data as part of cell qualification, alongside performance data from IEC 62660-1 and abuse data from IEC 62660-2, to build a complete safety case for cell selection.
References: IEC 62660-3:2022, IEC Webstore
Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.