Energy Storage Safety Standards Are Upgraded Again! Durathon Batteries Meet The New UL9540A-2025 Test Requirements, The “future” Of Salt Batteries Is Here!

With the rapid development of the global energy storage industry, the installed size of battery energy storage systems (BESS) is growing. However, the safety of energy storage systems, especially fires and explosions caused by thermal runaway, has been a concern. UL 9540A, a test method for evaluating the propagation of thermal runaway in energy storage systems, has gone through several revisions since it was developed in 2017 and is part of the fourth edition of the ANSI/CAN/UL 9540A Consensus Standard, which will be released in 2019. In addition, UL 9540A is the only U.S.-Canadian consensus standard referenced in NFPA 855 for large-scale fire testing.

As energy storage technologies such as lithium, sodium and Durathon batteries evolve, so do energy storage safety standards. The latest edition of ANSI/CAN/UL 9540A (2025 edition) expands testing of non-LiPo battery chemistries to include high-temperature molten salt batteries. The new regulation refines the criteria for determining thermal runaway propagation between cells, requires individual, module and system-level test data, and adds test conditions for new scenarios such as rooftop installations and garages. As the national standard for thermal runaway risk assessment of energy storage systems in the U.S. and Canada, UL 9540A provides a comprehensive consideration of the structural, electrical and thermal safety of energy storage systems, and the new version further raises the industry's safety threshold by covering a wide range of chemical systems and application scenarios.

UL 9540A关键标准变更

1. Clarification of the definition of thermal runaway propagation

■ Add a definition of thermal runaway propagation from cell to cell.

■ Specify the number of cells that trigger thermal runaway.

■ Update the module level criteria and add the temperature limit of the module shell.

2. Specialized test methods for batteries with multiple chemical systems

■ High-temperature molten salt batteries: add a full set of test methods for cells, modules, units and installation levels, including thermal runaway trigger conditions and gas composition analysis.

■ Liquid flow battery: optimize the testing process, clarify the electrolyte leakage control and thermal runaway criteria, and revise the report content requirements.

■ Traditional battery types (lead-acid, nickel-cadmium): add thermal runaway test at the core level, improve gas analysis and thermal diffusion assessment.

■ Explosion risk analysis: NFPA 68/69 and NFPA 855 HMA standard references have been added, requiring the validation of the energy storage system leakage program.

3. Differentiated test requirements for emerging application scenarios

■ Changes to improve the test requirements for indoor floor installation, indoor wall-mounted installation, outdoor wall-mounted installation, outdoor or open-air garage installation, combustible roof surface installation and other scenarios.

■ Installation level judgment changes, after triggering the unit test re-ignition only records, not judgment.

Durathon Batteries of Zhejiang AMPower Have Received UL 9540A Certification

AMPower has successfully obtained the UL 9540A certification on November 24, 2023, which is consistent with the new prescribed test standards implemented in 2025. It is also the first company in China to get UL 9540A certification for the electric core grade.

Durathon Battery UL 9540A Certification Key Interpretation

The diagram above shows the key points of the battery cell test. Thermal runaway of the core was observed, but there was no evidence of fire or rupture. Complies with Regulation 7.11 as added to UL 9540A:

For high temperature batteries, if thermal runaway cannot be initiated in the cell, or if no evidence of rupture of the cell casing and discharge of internal material is found, no further testing (i.e., module level, cell level, and installation level testing) is required.

Durathon batteries pass the first step of cell-level testing without the need for the next module-level, cell-level and installation-level testing, which is fundamentally different from lithium batteries and fully reflects their high safety characteristics.

Durathon High Temperature Battery Energy Storage Solutions

Durathon high temperature battery (operating temperature 270-350℃) adopts β-alumina ceramic solid state electrolyte, which has excellent thermal stability and chemical inertness compared with traditional liquid lithium battery. Its high-temperature operation characteristics and solid-state structure effectively block active substances, significantly reducing the risk of thermal runaway, and heat/gas release is more controllable, which perfectly matches the requirements of the new UL 9540A regulation on thermal runaway blocking capability.

Durathon high temperature battery is good at long time and large scale energy storage, providing more than 6 hours of continuous discharge capability, applicable to grid side peak shifting, load shaving, frequency and voltage regulation and other scenarios, and can also be used as a micro-grid or industrial park emergency backup power. Durathon battery system is containerized design, with the advantages of volume power density and compact arrangement. In terms of technical parameters, the operating temperature of Durathon battery is about 270℃-350℃, and the environmental adaptation range can cover -45℃ to +65℃; the cycle life can reach 6000-8000 times (about 15-20 years). Durathon batteries can work stably in cold or hot environments without additional air-conditioning assistance. Its molten active material and solid diaphragm structure ensure high thermal stability and extremely long life, making it ideal for long duration energy storage and high safety applications.

Core Security Certifications and High Security

In summary, the Durathon high temperature battery not only has natural safety suitability under the new version of UL 9540A rules, but also through the practice of IEC61000, UL1973 and other certificates as well as a variety of stringent safety tests: fire exposure, rod penetration, bullet impact, drop test, saltwater exposure, overcharge event, impact test and so on, have not happened to catch fire and explode, which further validates its high safety and compliance, providing users with a reliable energy storage guarantee.