Key Findings
The large-scale fire test (LSFT) confirmed that thermal runaway initiated in one PowerTitan 3.0 BESS container did not propagate to adjacent BESS containers or the medium-voltage substation (MVS). Despite internal temperatures in the initiating container (Container A) reaching 1259.8°C, the highest cell temperatures in adjacent containers remained below their thermal runaway thresholds. All containers, including Container A, remained structurally intact without deformation and could be lifted as complete units following the test.
Technical Details
The test was conducted in China by UL Solutions in accordance with UL 9540A: 2026 and CSA/ANSI C800-2025, with witnessing by the Fire Risk Alliance (FRA) and observation by Jensen Hughes. The setup replicated a utility-scale installation consisting of:
- 28.56 MWh of fully liquid-cooled PowerTitan 3.0 BESS in 20ft configurations.
- A 7.4 MW medium-voltage substation (MVS).
- A layout featuring Containers A–E, with the initiating and one adjacent container installed back-to-back.
To simulate extreme conditions, the BESS was at 100% state of charge. All active fire suppression and thermal management systems were disabled, and rooftop pressure-relief panels on the initiating container were fully opened to maximize oxygen availability. The test ran for 7.5 hours under uninterrupted monitoring. To protect the environment, the facility utilized ultra-large ventilation and hoods to treat all smoke and gases.
Background and Significance
According to Roger Li, general manager of the utility-scale product line at Sungrow, the test validates that safety must be engineered into the product through a combination of cell performance, system integration, thermal management, and structural protection. Benjamin Liu of UL Solutions noted that Sungrow’s approach of using pre-test assessments to predict fire behavior, followed by physical validation, significantly reduces the potential scale of loss by containing fire and preventing propagation.
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