IEC 62933-1 establishes the vocabulary and terminology for electrical energy storage (EES) systems, published by the International Electrotechnical Commission (IEC). It is Part 1 of the IEC 62933 series and provides the common language and definitions that underpin the technical standards for EES systems across the rest of the series, covering performance testing (IEC 62933-2), safety requirements (IEC 62933-5), and environmental assessment (IEC 62933-4).
Published by: International Electrotechnical Commission (IEC)
Current edition: IEC 62933-1:2018
Part of series: IEC 62933-2-1 (performance testing), IEC 62933-2-2 (application testing), IEC 62933-5-1 (grid-integrated safety)
Scope
IEC 62933-1 applies to all types of electrical energy storage systems that convert electrical energy to another form for storage and reconvert it to electrical energy when needed. This includes electrochemical storage (lithium-ion, lead-acid, flow batteries), mechanical storage (flywheels, pumped hydro), and thermal storage systems connected to the electrical grid or operating in islanded mode. The terminology standard covers the system architecture, components, operational modes, performance parameters, and safety terminology used across the industry.
Key Definitions
IEC 62933-1 defines fundamental EES system terms including the energy storage unit (ESU), the power conversion system (PCS), the energy management system (EMS), round-trip efficiency, rated energy, rated power, state of charge (SoC), state of energy (SoE), state of health (SoH), depth of discharge (DoD), and cycle count. It also defines grid service terminology including frequency regulation, peak shaving, load shifting, and islanding, which are the primary applications for grid-connected EES systems.
Relevance to Battery Engineering
IEC 62933-1 terminology is the reference vocabulary for technical communication between battery manufacturers, system integrators, grid operators, and regulators in the BESS industry. Consistent use of standardised terms avoids ambiguity in specifications, contracts, and technical standards. For battery engineers working on BESS projects, familiarity with IEC 62933-1 definitions ensures that datasheets, system specifications, and performance test reports use terms in the sense intended by IEC 62933-2 performance standards — particularly for parameters like rated energy, rated power, and round-trip efficiency, where different definitions can lead to significantly different numerical values and misleading comparisons between competing products.
Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.
See also: Global Standards Certifications for BESS