Sunwoda’s 5 MWh liquid-cooled BESS underwent the fire test for up to 12 hours, which was conducted and reviewed by the CSA group and Atar Fire’s Fire Protection Engineer, respectively
The SoC of all units was kept at 100%, while the fire suppression functions were deliberately kept inactive during the test
This test was conducted in accordance with ANSI/CAN/UL 9540A:2026 Sixth Edition and CSA/ANSI C800:2025 standards
Sunwoda, a battery energy storage system (BESS) maker, has completed extreme fire testing on its containerized 5 MWh liquid-cooled product. The company says this testing validates the performance of passive safety mechanisms built into the BESS in large-scale fire incidents, keeping other active features inactive and without manual intervention.
During testing, the company deployed 5 units to replicate a real-time high-density installation. With the target unit at the center, the other 4 units were placed in a back-to-back or side-by-side configuration with a 15 cm spacing. Meanwhile, all units were charged to a 100% State of Charge (SoC) level with fire suppression functions kept inactive, to mimic a worst-case scenario. To depict a more demanding scenario of thermal runaway propagation, the explosion vent and ventilation panels of the initiating unit were opened, and thermal barrier materials were also removed.
According to the company, the internal temperature peaked at a level that was contained within the closed enclosure doors during sustained combustion for up to 12 hours. Its structural integrity was also not compromised throughout the testing. In addition, there was no thermal runaway propagation to adjacent units. These measurements validate the system’s deflagration performance and the enclosure’s thermal insulation and fire containment capabilities.
This test procedure was conducted in accordance with ANSI/CAN/UL 9540A:2026 Sixth Edition and CSA/ANSI C800:2025 standards. It was conducted by the CSA group and reviewed by Atar Fire’s Fire Protection Engineer.
