It burned for 7.5 hours at 1260°C. Neighboring BESS units remained unaffected

Chinese giant Sungrow has subjected its latest PowerTitan 3.0 energy storage system to an extreme safety test. The large-scale fire test (LSFT) was conducted by the independent organization UL Solutions. The test took place in China in accordance with the latest UL 9540A:2026 and CSA/ANSI C800-2025 standards.

1259.8°C with fire suppression systems disabled

The primary objective of the test was to trigger a controlled, rapid thermal runaway event in one of the containers and determine whether the fire would spread to neighboring BESS units and the medium-voltage station.

To make the test conditions as challenging as possible and simulate the worst-case scenario:

• the test used a liquid-cooled block with a total capacity of 28.56 MWh, connected to a 7.4 MW transformer station.
• all batteries were charged to 100% state of charge (SOC).
• all active fire protection and cooling systems were deliberately disabled.
• the pressure relief panels (explosion vents) on the roof of the burning container were fully opened.

Structural integrity maintained, zero fire propagation

The test continued uninterrupted for 7.5 hours. Although the temperature inside the burning container A reached 1259.8°C, the fire did not spread to any of the neighboring containers (B, C, D, E) or the medium-voltage station (MVS). Cell temperatures in the adjacent units remained below the critical thermal runaway threshold.

Importantly for emergency responders and investors, the damaged container maintained its full structural integrity. After the fire was extinguished and the container had cooled down, it could be lifted by a crane as a single intact module without any risk of falling apart.