BESS fire test completed by CLOU Electronics in China
Iain Hoey
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Large-scale BESS test withstands high heat without thermal spread
CLOU Electronics has reported that its Aqua C2.5 5MWh liquid-cooled BESS successfully completed a 59-hour and 10-minute large-scale fire test.
The test was witnessed and documented by CSA Group personnel in full.
According to the company, the test subjected the system to flames exceeding 1,300°C and showed no thermal runaway propagation to nearby battery enclosures.
The structure reportedly maintained full integrity throughout the fire.
CLOU Electronics stated that the test replicates worst-case fire scenarios in centralised energy storage installations, aiming to evaluate whether fire can spread between enclosures.
The company explained that the results would be used to inform improvements in BESS site fire protection planning.
CSA Group witnesses BESS test performance
The test involved igniting one battery container, referred to as Container A, and allowing the fire to develop naturally until extinguishment.
CSA Group, which observed the full test, verified that no neighbouring systems experienced safety breaches, such as pressure valve activation or thermal runaway.
CLOU Electronics reported that the test achieved a complete combustion duration of 59 hours and 10 minutes.
It confirmed that the fire did not reignite after attenuation.
The company added that the flame-retardant and thermal insulation features of the Aqua C2.5 system played a central role in this performance.
This aligns with the client’s custom test requirements.
CLOU outlines fire progression simulation methods
CLOU Electronics stated that the methodology simulated the full cycle of fire development: ignition, escalation, and attenuation.
The firm explained that this process enabled collection of critical safety parameters for energy storage plant protection system design.
CLOU Electronics said that the data would support enhanced system response planning in the event of future fire scenarios.
It also noted that the test helped validate how high-temperature events could be sustained without triggering safety incidents in adjacent containers.
The company further confirmed that these outcomes support risk-informed approaches to facility-scale BESS integration.
System director highlights design rationale
Eric Wang, System Director of CLOU ESS Division, said: “The test results have far exceeded our most stringent safety benchmarks.”
He added: “CLOU’s integrated approach combining superior flame retardancy, advanced thermal management and inherent system protection represents a significant advancement in energy storage safety engineering.”
Wang explained: “The solution’s forward-looking design is specifically engineered to address emerging challenges posed by high-energy-density battery technologies.”
Wang stated that the system’s performance is intended to meet the increasing safety demands of next-generation storage.
He said the test reinforced the operational viability of the Aqua C2.5 system for grid-scale deployment.
Implications for certification and deployment
According to CLOU Electronics, the system’s containment performance offers a new standard for certification-level testing.
The firm stated that this may affect approval processes for BESS products in multiple global markets.
CLOU Electronics added that the Aqua C2.5 system is ready for deployment at gigawatt scale in utility, commercial and industrial settings.
It reported that the test shows that long-duration fire events can be managed with no cascading system failure.
The company said the outcome demonstrates how fire resilience and operational efficiency can be delivered in tandem through system design.
BESS fire test completed by CLOU Electronics in China: Summary
CLOU Electronics has completed a 59-hour and 10-minute large-scale fire test on its Aqua C2.5 BESS.
The test was conducted in China and fully observed by CSA Group personnel.
The fire reached temperatures above 1,300°C and did not cause thermal runaway propagation.
The structure remained intact throughout the test.
No neighbouring systems exhibited valve activity or containment breach.
The test was designed to simulate real-world fire conditions and assess spread between enclosures.
The system met the client’s customised performance criteria.
CLOU Electronics stated that the data collected will support fire protection system planning.
Eric Wang of CLOU ESS Division said the results exceeded the company’s internal safety standards.
He confirmed that the system is designed for high-energy-density applications.
CLOU Electronics reported that Aqua C2.5 is suitable for global utility-scale deployment.