For BESS buyers, certification is not one document that covers every market requirement. Different standards address different risks, product levels, and installation conditions.
In the US, UL 9540 covers integrated-system safety, UL 9540A provides thermal-runaway test evidence, and NFPA 855 addresses installation. In Europe, IEC standards provide battery- and system-level safety evidence, while EU legislation, CE marking, and national rules govern market access and project approval.
This guide explains what the main BESS certifications and standards do in the US and EU, how buyers can verify certification evidence, and which Chinese BESS products publicly list relevant UL and IEC compliance.
US requirements cover complete-system safety, thermal-runaway testing, and installation compliance. They apply at different levels and cannot replace one another.
Item | Primary role | Main level |
UL 9540 | Safety evaluation of the integrated energy storage system and equipment | Complete ESS/BESS |
UL 9540A | Thermal-runaway fire-propagation test method | Cell, module, unit, or installation test |
NFPA 855 | Installation requirements for stationary energy storage systems | Project / installation |
UL 9540 certification means that the specified BESS configuration has been evaluated as an integrated system, including its batteries, controls, power conversion equipment, and safety components. It provides system-level safety evidence but does not approve the final installation site.
UL 9540A is a test method, not a product certification. Its report records how thermal runaway develops and whether fire propagates within or between battery units. AHJs can use this data to assess separation distances and fire-protection measures.
NFPA 855 addresses how a stationary BESS is installed. Its requirements can cover system location, spacing, fire detection, suppression, explosion control, and emergency planning. Compliance means the site design follows the locally adopted requirements and is accepted by the AHJ.
The European market follows a structure of baseline standards, mandatory regulations, and manufacturer self-declaration.
Item | Primary role | Main level |
IEC 62619 | Safety requirements for industrial lithium cells and batteries | Cell/battery |
IEC 62933-5-2 | Safety requirements for grid-connected electrochemical energy storage systems | Complete BESS |
Regulation (EU) 2023/1542 | Legal requirements for batteries placed on the EU market | Battery/EU market |
CE marking and EU Declaration of Conformity | Conformity with applicable EU legislation | Product/EU market |
National rules and permits | Grid, fire, building, and environmental approval | Project/installation |
IEC 62619 specifies safety requirements and tests for secondary lithium cells and batteries used in industrial applications, including stationary energy storage. It provides battery-level safety evidence but does not demonstrate compliance of the complete BESS.
IEC 62933-5-2 addresses the complete grid-connected electrochemical energy storage system. It covers system-level hazards, subsystem interactions, and safety across the BESS lifecycle.
The current IEC edition is 2025, but existing product certificates may reference the 2020 edition. Buyers should check the edition shown on each certificate.
Regulation (EU) 2023/1542 establishes legally binding battery requirements. These include phased obligations concerning carbon footprint, recycled content, battery passports, and supply-chain due diligence.
The applicable requirements depend on the battery category and implementation date.
CE marking is not a certificate issued by the EU. Where it is required, the manufacturer must identify the applicable EU legislation, follow the required conformity-assessment procedure, prepare technical documentation, and sign an EU Declaration of Conformity.
The CE mark can only be affixed after the applicable requirements have been addressed.
National rules cover grid connection, electrical safety, fire protection, building, environmental, and permitting requirements. Compliance determines whether the completed BESS project can be approved, connected, and operated at its location.
Buyers sourcing a BESS for the US or European market can verify certification evidence through four core steps.
Distinguish between cell-, battery-, and complete-system certification. Confirm that the evidence covers the supplied BESS, including its battery, BMS, PCS, and fire-protection configuration, rather than only an individual cell.
Compare the certified model, cell manufacturer, BMS firmware, and fire-protection design with the purchase contract and final bill of materials. The certified configuration must match the equipment being delivered.
Do not rely only on a PDF. Check the certificate number, status, manufacturer, model, and factory information through an official database such as UL Product iQ or TÜV Rheinland Certipedia.
For US projects, review the applicable UL 9540A data and NFPA 855 requirements. For European projects, verify national grid, electrical, fire, building, and permitting rules with the relevant local authorities. Confirm that system spacing, ventilation, and fire-protection design meet the requirements of the local authority or AHJ for project approval and operation.
HiTHIUM is a Chinese manufacturer of energy storage cells and BESS products. It publishes model-specific UL and IEC certification information. Among Chinese storage products, HiTHIUM’s ESS Cell 314Ah, ∞Cell 587Ah, ∞Cell 1175Ah, and ∞Power 6.25MWh 4h have publicly listed UL and IEC certification or test evidence.
HiTHIUM product | Publicly listed evidence | Evidence scope |
ESS Cell 314Ah | IEC 62619; UL 1973; UL 9540A test evidence; GB/T 36276; UN 38.3 | Cell-level safety and transport evidence |
∞Cell 587Ah | IEC 62619; UL 1973; UL 9540A test evidence; GB/T 36276; UN 38.3 | Cell-level safety and transport evidence |
∞Cell 1175Ah | IEC 62619; UL 1973; UL 9540A test evidence; UN 38.3 | Cell-level safety and transport evidence |
∞Power 6.25MWh 4h | UL 1973; UL 9540A test evidence; UL 9540 certification;IEC 62933-5-2:2020 certification(TÜV Rheinland, Certificate R 50700399) | Complete-system safety and compliance evidence |
The ∞Power 6.25MWh 4h integrates the ∞Cell 1175Ah into a complete BESS. Its IEC 62933-5-2:2020 certification is recorded by TÜV Rheinland under certificate R 50700399, while HiTHIUM also lists UL 9540 certification for the system.
In October 2025, twelve ∞Power 6.25MWh 4h containers were shipped to Europe, confirming the system’s commercial delivery in an international market. The system-level certifications and commercial delivery demonstrate HiTHIUM’s ability to align BESS development with international safety requirements and supply certified configurations for real projects.
HiTHIUM’s safety validation also extends to sodium-ion technology. The ∞Cell N162Ah passed the safety tests specified in GB/T 44265, including drop, crush, short-circuit, overcharge, over-discharge, and thermal-runaway tests. This expands HiTHIUM’s product-specific safety evidence across both lithium-ion and sodium-ion storage technologies.
BESS certification requirements must be checked at the market and product level. US projects use UL 9540 for system safety, UL 9540A for thermal-runaway test evidence, and NFPA 855 for installation. European projects combine IEC 62619, IEC 62933-5-2, applicable EU legislation, CE documentation, and national project requirements.
Buyers should verify the exact model, evidence scope, document status, and final project configuration. HiTHIUM supports this process with model-specific safety and compliance evidence for its energy storage cells and complete BESS products.
Contact HiTHIUM to review the certification documentation required for your BESS project.
[1] UL Solutions. Energy Storage System Testing and Certification.
https://www.ul.com/services/energy-storage-system-testing-and-certification
[2] UL Solutions. UL 9540A Test Method for Battery Energy Storage Systems.
https://www.ul.com/services/ul-9540a-test-method
[3] National Fire Protection Association. NFPA 855 Standard Development.
https://www.nfpa.org/codes-and-standards/nfpa-855-standard-development/855
[4] International Electrotechnical Commission. IEC 62619:2022.
https://webstore.iec.ch/en/publication/64073
[5] International Electrotechnical Commission. IEC 62933-5-2:2025.
https://webstore.iec.ch/en/publication/68297
[6] European Union. Regulation (EU) 2023/1542 Concerning Batteries and Waste Batteries.
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX%3A32023R1542
[7] European Commission. CE Marking.
https://europa.eu/youreurope/business/product-rules-compliance/general-product-compliance/ce-marking/index_en.htm
[8] UL Solutions. Product iQ Certification Database.
https://productiq.ulprospector.com/
[9] TÜV Rheinland. Certificate R 50700399.
https://www.certipedia.com/certificates/50700399?locale=en
Previous: