IEC 63056 - Battery Design

Safety Requirements for Secondary Lithium Cells and Batteries for Use in Electrical Energy Storage Systems (EESS)

IEC 63056 is an international standard published by the International Electrotechnical Commission (IEC) that specifies safety requirements and test methods for secondary lithium cells and batteries intended for use in electrical energy storage systems (EESS) for stationary applications. It builds on and complements IEC 62619 (industrial Li battery safety) and was developed specifically to address the unique characteristics and hazards of batteries deployed in grid-connected or off-grid stationary EESS, including home energy storage, commercial BESS, and utility-scale installations. IEC 63056 covers higher voltage classes (up to 1500 V DC) and larger energy content than typical industrial batteries covered by IEC 62619 alone.

Published by: International Electrotechnical Commission (IEC)

Current edition: IEC 63056:2020 (1st edition, December 2020)

Complements: IEC 62619 (industrial Li battery safety) — 63056 adds EESS-specific requirements on top of 62619

European adoption: EN IEC 63056:2021 / BS EN IEC 63056:2021

Scope

IEC 63056 applies to secondary lithium cells, batteries, and battery systems intended for use in electrical energy storage systems (EESS) for stationary applications, including:

Residential EESS: home energy storage, solar-plus-storage, backup power units
Commercial and industrial EESS: C&I behind-the-meter storage, demand charge management, UPS-integrated storage
Utility-scale BESS: grid-scale battery energy storage systems (BESS) from hundreds of kWh to multi-MWh
DC bus voltage: covers systems up to 1500 V DC — enabling large series-connected battery strings used in utility-scale BESS

Exclusions: Traction batteries for road vehicles are excluded. The standard does not replace IEC 62619 but is applied in conjunction with it. Power conversion equipment, grid connection, and installation requirements are addressed by other standards (IEC 62477, IEC 61000 series, NFPA 855).

Key Requirements and Test Methods

Baseline from IEC 62619

IEC 63056 requires that batteries for EESS first meet the requirements of IEC 62619:2017 (or later editions). The standard then adds EESS-specific requirements not addressed in IEC 62619:

EESS-Specific Additional Tests

High-voltage insulation withstand: test at voltages relevant to the 1500 V DC class — confirms insulation integrity at elevated operating voltages not addressed by the lower-voltage focus of IEC 62619
Altitude test (updated): verifies battery and enclosure integrity at altitudes corresponding to elevated battery storage locations (data centres, rooftop installations)
Humidity and moisture ingress: combined humidity and thermal cycling test specific to outdoor and semi-outdoor EESS enclosures
Thermal runaway propagation: mandatory for systems above a defined energy threshold; test protocol requires triggering thermal runaway in a single cell and demonstrating that the battery enclosure contains or manages the event without causing fire or explosion at the system boundary
Cell and module thermal management: testing to confirm that the thermal management system (TMS) prevents cells from exceeding maximum operating temperatures under defined load conditions and at ambient temperature extremes
Battery management system (BMS) functional testing: BMS must demonstrate correct protection response to overvoltage, undervoltage, overcurrent, and overtemperature fault conditions; mandatory communication interface testing (CAN, Modbus, or equivalent)

Documentation and Marking

Safety data sheet: manufacturer must provide a cell-level and system-level safety data sheet documenting hazards, first responder information, and disposal requirements
Marking: battery system must be marked with rated voltage, rated energy capacity, maximum charge/discharge current, operating temperature range, and safety symbol
Recycling and end-of-life markings: EU WEEE and national end-of-life disposal symbols required on batteries sold in relevant markets

Regional Recognition and System Standards

Europe: EN IEC 63056:2021 is referenced in EU CE marking for EESS under the Low Voltage Directive (LVD 2014/35/EU) and the EU Battery Regulation for stationary storage applications
Germany VDE: VDE-AR-E 2510-2 (residential battery system installation) references IEC 63056 as the underlying safety standard for lithium battery compliance
Australia/New Zealand: AS/NZS 5139 (installation of battery energy storage systems) references IEC 63056 for battery safety compliance
UK: BS EN IEC 63056:2021 adopted; referenced in OZEV/DNO grid-connected home storage programmes

Related Standards

IEC 62619 — Safety requirements for industrial Li batteries; IEC 63056 builds on and extends 62619 for EESS applications
UL 9540 — US system-level standard for ESS; the US counterpart to IEC 63056 at system level
UL 9540A — Thermal runaway fire propagation test method for BESS
UL 1973 — US standard for stationary batteries; referenced in UL 9540 certification process
NFPA 855 — Installation standard for stationary ESS; specifies installation requirements for systems meeting IEC 63056/UL 9540
IEC 62477-1 — Safety requirements for power electronic converter systems and equipment (covers the power conversion/inverter side of EESS)

Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.