CLOU Electronics' details its Aqua-C2.5 BESS fire test results

CLOU Electronics, an energy technology company based in China, has given more details regarding its successful completion of the CSA TS-800 fire safety test for its Aqua-C2.5 5 MWh liquid-cooled battery energy storage system (BESS).

ESS News reported on successful testing by CLOU Electronics on its Aqua-C2.5 liquid-cooled, rack-based system under the CSA TS-800 protocol back in February, where it also achieved third-party certification by TÜV Rheinland.

At that time, four 20-ft cabinets endured simulated fire conditions, exceeding 1 000 °C for 48 h, while adjacent units stayed under 40 °C.

Additional details about it and further tests have now been published.

Conducted for 59 hours and 10 minutes under extreme conditions, and under full supervision from CSA Group engineers, the Aqua-C2.5 demonstrated zero thermal propagation and full structural integrity, even as flames exceed 1,300°C.

The test was executed under maximal difficulty parameters from the CSA Group’s protocol, in a dense 20 MWh station layout, with four cabinets arranged side-by-side and back-to-back at 40% reduced clearance compared to industry norms. Primary fire suppression systems were deliberately disabled.

CSA TS-800: Beyond Compliance

The TS-800 protocol, introduced by CSA Group in 2024, aims to close the gap left by earlier standards such as UL 9540A by simulating real-world fire propagation in multi-container systems. The test covered four validation phases:

Thermal Runaway Initiation
Propagation Resistance
Structural Integrity
Post-Test Functionality

Based on the four validation phases, the Aqua-C2.5 system withstood a deliberately induced thermal failure and 59 hours of sustained fire without spread to nearby units, showing its structural integrity with just 1.2 mm displacement and preserving 92% component functionality in the affected unit (Cabinet A).

Metric	Cabinet A (Ignited)	Cabinet C (Adjacent)	Industry Standard
Peak Temperature	>1300°C	80.71°C	<200°C
Structural Deformation	1.2 mm	0.3 mm	<5 mm
Pressure Events	3 controlled	0	N/A
Post-Test Functionality	92% operational	100% operational	N/A

The Aqua-C2.5 now meets CSA TS-800, UL 9540A, IEEE693, and IEC 62933-5-2 standards.

According to CLOU Electronics, its system enables 34% denser installations than current norms, 80% reduction in auxiliary fireproofing materials and is suitable for deployment in urban microgrids and critical infrastructure.

Prevalon Energy successfully completed the CSA TS-800 test back in April for its 6 MWh HD5 energy storage platform.

Eric Wang, System Director of CLOU ESS Division, said: “The test results have far exceeded our most stringent safety benchmarks … the solution’s forward-looking design is specifically engineered to address emerging challenges posed by high-energy-density battery technologies.”