Stationary Battery Standards: IEC 62619, UL 1973, UL 9540 & UL 9540A
Short answer: IEC 62619 covers safety of lithium cells and batteries for industrial use. UL 1973 addresses battery systems for stationary applications. UL 9540 certifies complete energy storage systems. UL 9540A is a test method for fire propagation during thermal runaway, not a certification mark. Each operates at a different level, and none substitutes for the others.
Building or procuring a stationary lithium battery system means navigating four overlapping standards that each address a different scope and a different level of the stack. Confusion about what each one covers, and what it explicitly does not, leads to gaps in a project's compliance documentation and to misplaced assumptions between buyer and supplier. This article maps each standard clearly so that integrators and purchasers can ask the right questions at each tier.
The four standards and where they sit
Before comparing them in detail, one structural point matters: a test or certification at the cell or module level does not automatically propagate upward. A module that carries documentation under IEC 62619 has not thereby been assessed under UL 9540. The integrator who assembles a system is typically the one who closes that gap, either by commissioning system-level testing or by working within a listed system configuration.
IEC 62619: safety of lithium cells and batteries for industrial use
IEC 62619, published by the International Electrotechnical Commission (iec.ch), sets safety requirements for secondary lithium cells and batteries intended for use in industrial applications, which includes stationary energy storage. It covers the cell itself and battery assemblies (a group of cells with interconnections and protective circuitry), not the wider system or its installation.
The standard addresses abuse conditions such as external short circuit, impact, thermal abuse, overcharge and forced discharge, and it sets requirements for the protective functions that must accompany a battery assembly. The test list depends on the edition of the standard, so the edition named in a supplier's documentation matters. What it does not do is assess how a battery behaves when integrated into a rack, container or building, nor does it address fire propagation to adjacent systems.
For a prismatic LFP or NCM module supplied as a component, IEC 62619 is the usual reference point for cell- and module-level safety. Which documentation exists for a given product is something the buyer establishes per product and per project, for example for the battery modules in a planned build.
UL 1973: batteries for stationary and vehicle auxiliary applications
UL 1973 is a UL standard for batteries used in stationary applications (and certain vehicle auxiliary roles). Where IEC 62619 is oriented toward the cell and battery assembly, UL 1973 is oriented toward the battery as a functional unit intended for installation: it covers the battery's electrical and mechanical construction, the management electronics, communications, and requirements for safe operation over its rated service life.
UL 1973 is most relevant in North American markets and for systems destined for installations where Authority Having Jurisdiction (AHJ) acceptance is required. It is a product certification standard: a battery carries a UL 1973 listing when the specific product configuration has been evaluated and listed by UL. A module supplied without that listing is not a listed product under UL 1973, regardless of what cell-level documentation it carries.
UL 9540: energy storage systems and equipment
UL 9540 operates one level higher than UL 1973. It covers complete energy storage systems (ESS): the combination of battery, power conversion, controls, and any ancillary equipment that together form a system placed into service. Listing under UL 9540 means that the complete system configuration, in the exact bill of materials and configuration submitted, has been evaluated.
This is the standard that AHJs in North America often require for the installed system. It draws on the component-level listings (UL 1973 for the battery, UL 1741 for inverters, and others) but cannot be assembled from them: the system itself must be listed. The integrator, system manufacturer or EPC contractor is the party that typically pursues UL 9540 listing, not the cell or module supplier.
UL 9540A: test method for thermal runaway fire propagation
UL 9540A is frequently misread as a certification. It is a test method, not a listing standard. Its full title describes it as a test method for evaluating thermal runaway fire propagation in battery energy storage systems. The test is conducted at four levels, cell, module, unit and installation, and the results inform the fire-separation and suppression requirements for a given installation.
A module that has been through UL 9540A testing has test data on file; it does not hold a UL 9540A certification, because no such certification exists. The test data is used by the AHJ and by the fire engineer to determine how much separation distance or suppression capacity is required. Some jurisdictions require UL 9540A test data as a condition of permitting; others accept it as one input among several.
For the integrator, the practical implication is this: UL 9540A test data on the module is useful and sometimes required, but it is distinct from a UL 9540 system listing.
Standards comparison table
| Standard | Level | What it covers | What it does not cover |
|---|---|---|---|
| IEC 62619 | Cell and battery assembly | Safety of lithium cells and industrial battery assemblies under abuse conditions; requirements on protective functions | System integration, fire propagation, installation requirements |
| UL 1973 | Battery (as installed unit) | Construction, management electronics, communications and service-life safety of stationary batteries; product listing | Complete system configuration, fire separation, inverter and controls integration |
| UL 9540 | Complete ESS | Full system evaluation in a specific configuration: battery, power conversion, controls and enclosure together | Individual components in isolation; configurations not submitted for listing |
| UL 9540A | Cell → module → unit → installation (four-level test method) | Fire propagation behaviour during thermal runaway at each level; produces test data | Certifies nothing; does not replace IEC 62619 or UL 9540; not a listing |
| UN 38.3 | Cell and battery (transport) | Safety during air, sea and road transport; vibration, altitude, thermal cycling, short circuit | Stationary operation, installation safety (see the shipping article) |
UN 38.3 appears in the table for completeness: it is a transport test and is a prerequisite for shipping lithium cells and batteries, not a stationary safety assessment. It does not substitute for any of the four standards above. For detail on transport requirements, refer to the article on shipping lithium battery modules.
What the integrator owns
The division of responsibility follows the level structure above. A cell or module supplier can provide documentation at the cell and battery assembly level (IEC 62619 scope) and, where applicable, UL 1973 listing for the module. The supplier cannot provide UL 9540 listing, because that listing covers a system configuration the supplier does not control.
The integrator who assembles complete module systems into a rack or container is the party who determines the system configuration and, where required, pursues system-level certification. This is not a gap in the supply chain; it is the structural logic of the standards themselves. The cell supplier, the module supplier and the system integrator each hold the documentation appropriate to their scope.
For energy storage solutions built around standardised prismatic modules, the starting point is confirmed documentation at the module level, followed by system-level evaluation carried out by or on behalf of the integrator.
Questions to put to a module supplier
When evaluating a module for a stationary application, the following questions establish what documentation actually exists and at what scope:
- Against which standard has this specific module been tested or evaluated (IEC 62619, UL 1973 or another), and does the documentation name the exact product type and configuration?
- Who conducted the testing or evaluation: an accredited third-party laboratory, a notified body, or internal testing?
- Is there a test report or certificate available, and does it cover the cell chemistry, cell format and module configuration you intend to use?
- Has UL 9540A testing been conducted on this module, and if so, at which levels (cell, module, unit)? Is the test report available?
- What does the module documentation explicitly not cover, and what system-level testing is the integrator expected to provide?
These questions apply regardless of supplier. The answers determine what the integrator still needs to arrange before the system can be permitted and installed.
The cell and module catalogue lists the product types; which documentation applies is confirmed per product.
Frequently asked questions
What does IEC 62619 actually certify for a lithium battery module?
IEC 62619, published by the IEC at iec.ch, sets safety requirements for lithium cells and battery assemblies in industrial use. A cell or battery assembly evaluated under IEC 62619 has been assessed for safety under abuse conditions at the cell and assembly level. It does not cover system integration, fire propagation or installation requirements.
Is UL 9540A a certification mark that a module can carry?
No. UL 9540A is a test method for measuring fire propagation behaviour during thermal runaway, conducted at cell, module, unit and installation levels. It produces test data, not a listing or certification mark. There is no such thing as a UL 9540A-certified product; the data is used to inform installation and fire-separation requirements.
Does a UL 1973-listed battery automatically satisfy UL 9540?
No. UL 1973 covers the battery as a unit. UL 9540 covers the complete energy storage system in a specific configuration, including power conversion and controls. A UL 1973 listing is one input to a UL 9540 evaluation but does not replace it. The system integrator or manufacturer typically holds the UL 9540 listing.
Who is responsible for obtaining UL 9540 listing for a stationary storage system?
The party who defines and markets the complete system configuration, typically the system integrator, system manufacturer or EPC contractor, is responsible for pursuing UL 9540 listing. The module supplier provides component-level documentation; system-level listing is outside the supplier's scope because it depends on the full bill of materials and configuration.
Does UN 38.3 transport certification count as a stationary safety assessment?
No. UN 38.3 is a transport safety test covering vibration, altitude, thermal cycling, short circuit and related hazards during shipping. It is a prerequisite for transporting lithium cells and batteries by air, sea or road. It does not assess stationary operation, installation safety or fire behaviour, and does not substitute for IEC 62619, UL 1973, UL 9540 or UL 9540A.
Discuss your system requirements
If you are specifying modules for a stationary application and need to confirm what documentation is available at the module level, contact Avantis Energy to discuss your project and the documentation scope relevant to your configuration.