On June 11, 2025, during the 18th SNEC, Hithium, a prominent global energy storage technology company, hosted a product safety technology sharing event titled “Leading the Future, Forged for Safety.” At this event, they unveiled the complete results of the world’s first all open-door large-scale fire test of their ∞Block 5MWh energy storage system. Additionally, they received large-scale fire test certification from the international testing authority, UL Solutions.
Hualei Wang, the project manager for the fire test, provided an overview of the test background and key details. Attendees were shown a video that documented the open-door fire test, offering insights into the procedure, technical highlights, and outcomes. The test involved intentionally heating eight battery cells inside container A to induce thermal runaway, which subsequently caused cell-to-cell propagation. As the battery’s pressure relief vents opened, an ignition system ignited the released gases, initiating full combustion while the container doors remained wide open to allow a continuous supply of oxygen. This setup aimed to maximize heat exposure to adjacent containers B, C, and D.
The test was conducted under four extreme conditions: all doors open during combustion, dual 15 cm extreme spacing, the fire suppression system turned off, and a 100% State of Charge (SOC).
**Peak Fire Phase:** At the fourth hour of testing, the fire reached a peak temperature of 1,372°C. Temperature monitoring confirmed that the cell temperatures in all adjacent containers remained significantly below the thermal runaway initiation threshold set by the UL9540A cell-level test (≤42°C in Container B, ≤80°C in Container C, and ≤70°C in Container D).
**Sustained Combustion Phase:** After 15 hours, the open flame was extinguished. Remarkably, the initiating container retained its structural integrity without any deformation or collapse. No combustion or thermal runaway propagation occurred in the adjacent containers, which only experienced minor surface damage, while the internal battery modules remained completely unaffected.
The successful completion of the test was made possible by Hithium’s multi-layered safety architecture, which spans cell, module, and system levels. At the cell level, heat-resistant anode and cathode materials, functional electrolyte additives, and high-temperature separators raised thermal thresholds. At the module level, low-conductivity insulation and flame-retardant covers minimized the risk of propagation. At the system level, a high-strength container frame and heat-resistant enclosure materials ensured structural stability under extreme heat.
During the event, UL Solutions presented Hithium with certification for the large-scale fire test, acknowledging its compliance with UL 9540A and NFPA 855 standards. Qifeng Xiao, General Manager of the Energy and Automation Division for Asia Pacific at UL Solutions, remarked at the certification ceremony, “Hithium’s pioneering open-door extreme fire test was the first conducted under full oxygen exposure—far exceeding the industry standard closed-door explosion vent fire test model. The positive outcome not only validated the system’s inherent fire protection but also established a critical reference for the development of global energy storage safety standards.”
This groundbreaking fire test not only showcased Hithium’s technical prowess but also reflected their unwavering confidence in the safety performance of their energy storage systems through a fully transparent testing process. The data and practices derived from this test are invaluable contributions to the industry. Hithium remains committed to investing in safety innovation, further securing the pathway to a global transition toward green energy.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/hithium-sets-new-safety-standards-for-energy-storage-with-groundbreaking-open-door-fire-test-at-snec-2025/
