World’s first open-door fire test validates safety of 6.25MWh battery

Chinese energy company HiTHIUM has successfully completed the world’s first open-door fire test on a large-scale 6.25 megawatt-hour (MWh) battery energy storage system, marking a significant advancement in grid-scale battery safety validation. Conducted under strict oversight from UL Solutions, U.S. authorities, and fire protection engineers, the test adhered to the latest UL 9540A (2025) and NFPA 855 (2026) standards. Unlike controlled lab tests, this trial simulated worst-case real-world failure conditions by leaving container doors open to maximize oxygen supply and placing adjacent battery containers extremely close together. The results demonstrated that the system remained stable and predictable under extreme abuse, addressing concerns about fire escalation, violent failures, and cascading damage in high-energy-density battery installations. Key safety innovations included a three-dimensional airflow channel with directional venting and dual-pressure relief valves that managed gas release during thermal runaway without reaching explosive pressures or ejecting debris. Fire-resistant module covers, reinforced steel