As energy storage systems continue to scale toward higher capacity and higher energy density, safety validation is moving beyond single-system assessment toward project-level scenarios. Evolving international standards such as UL 9540A and CSA C800 are also driving the industry toward more application-relevant testing. Against this backdrop, Sunwoda carried out the large-scale fire test in a more stringent setup than typical real-world deployment, further validating the safety boundaries of its 5MWh Liquid Cooling ESS.
Test Design Under Extreme Conditions
The test adopted a configuration of five actual full-scale 5MWh Liquid Cooling ESS systems, including one initiating unit and four target units. The ESS containers were arranged with a minimum spacing of 15 cm, resulting in a denser layout than typical project configurations. To enhance test severity, all five systems were tested at 100% state of charge, while the active fire suppression system was disabled. In the initiating unit, explosion vent panels and ventilation panels were opened, and key thermal barrier materials were removed to create a more demanding environment for thermal runaway propagation.
This test was carried out in accordance with ANSI/CAN/UL 9540A:2026 Sixth Edition, and CSA/ANSI C800:2025. To ensure a rigorous process and credible results, the test was conducted by CSA Group and reviewed by Atar Fire's Fire Protection Engineer.
Beyond Fire Prevention: Validating Risk Containment
Rather than focusing only on whether a system catches fire, the test further evaluated whether fire and thermal risks could be effectively isolated and prevented from spreading under extreme conditions.
During the test, the initiating unit experienced thermal runaway and sustained combustion for over 12 hours. The results showed that the fire remained contained within the initiating unit, with no propagation to adjacent units. Structural integrity was maintained throughout the test, with no collapse observed. All test criteria were satisfied. These results confirm Sunwoda’s ESS fire containment capability in dense, multi-container deployment scenarios.
This performance is underpinned by Sunwoda’s coordinated system-level safety design. Across cells, PACKs, and systems, multiple protective measures work together to delay heat transfer, reduce thermal impact between adjacent systems, and support the containment of thermal runaway.
Advancing Safer, More Reliable Energy Storage at Scale
As energy storage systems move toward higher capacity and higher energy density, safety validation must go beyond standard requirements and move closer to real-world deployment conditions. Through this large-scale fire test, Sunwoda further validated the safety boundaries of its high-capacity liquid cooling ESS and demonstrated its safety capabilities from design to delivery.
Looking ahead, Sunwoda will continue to strengthen its integrated capabilities across battery cells to system design, embedding safety, quality, and reliability throughout the full product lifecycle. As energy storage plays an increasingly important role in building flexible and resilient power systems, Sunwoda remains committed to supporting safe and reliable energy storage deployments worldwide.
