HEFEI, China, April 7, 2026 /PRNewswire/ — Sungrow’s Commercial and Industrial (C&I) Energy Storage System Power Guardian completed successfully thermal runaway testing at cell, module and unit level according to UL 9540Abecoming the the industry’s first modular DC-coupled C&I ESS to achieve three-level certification. Witness to TÜV Rhinelandtesting validates PowerKeeper’s ability to effectively prevent the spread of thermal runaway across multiple layers of the system, setting a new benchmark for safety in commercial and industrial energy storage.
Beyond Single-Tier Testing: A New Approach to Energy Storage Security
In commercial and industrial environments such as shopping malls, office buildings, hotels and factories, energy storage systems are often installed in high-density spaces where people, equipment and valuable assets coexist. Given these scenarios, security requirements go far beyond simple compliance. The fundamental challenge in battery safety is not simply responding to fires, but also preventing the spread by thermal runaway before the risks become serious.
UL9540A is widely recognized as the global benchmark for assessing thermal runaway risks in energy storage systems. However, current industry practices generally focus on single-level testing, either validating only cell-level parameters or demonstrating compliance only at the module or system level. Such fragmented testing cannot fully demonstrate whether each security barrier within a system may contain potential risks.
PowerKeeper addresses this challenge with a comprehensive three-tier security validation approach.
Build a complete security proof chain
Thanks to its triple UL 9540A cell-module-unit certification, PowerKeeper establishes a complete safety validation chain on three layers of the system:
- Cell-level testing captures critical thermal runaway parameters.
- Module level testing verifies that thermal runaway can be contained within the battery module.
- Unit level testing demonstrates effective thermal insulation between adjacent cabinets and surrounding structures.
These interconnected validation layers ensure that PowerKeeper can maintain system integrity even under extreme conditions.
Validated under real installation constraints
Commercial and industrial sites often have limited installation space, requiring energy storage systems to be placed close to walls or next to other cabinets. PowerKeeper enables seamless, space-saving installation, effortlessly adapting to diverse and complex site conditions. The test simulates real-world installation scenarios, with clearances set at just 25mm from walls and 450mm between cabinets.
– Unit Level Testing
The triggered battery cell reached a maximum temperature of 595.2°C. Even in such extreme conditions, PowerKeeper demonstrated exceptional containment capability.
- No impact on adjacent cabinets
Despite unit spacing of only 450mm, the neighboring unit recorded a maximum surface temperature of 13.7°C, well below the threshold of 141.3°C defined by UL 9540A.
- Safe operation with minimal wall clearance
With a distance to the wall of only 25 mm, the temperature rise on the wall surface was only 29°C, significantly lower than the limit of 97°C specified by the standard.
– Module Level: Precision Attenuation
During module-level testing, a thermal runaway was intentionally triggered in three cells. The results were conclusive: no combustion, no explosion and zero external debris or splashing. This confirms that all potential dangers are strictly contained within the PACK, even under triggered conditions.
– At the cellular level: source control
The cell’s explosion-proof valve activated instantly, successfully releasing pressure and preventing any combustion or explosion, while accurately capturing the thermal runaway trigger temperature of 216.3°C during cell-level testing.
These results confirm that PowerKeeper can operate safely even in space-constrained environments, effectively containing potential risks within tightly controlled limits.
From passive protection to intelligent security
While the UL 9540A certification validates the PowerKeeper’s passive safety performance in extreme conditions, Sungrow has also integrated advanced active safety mechanisms to protect everyday operation.
Aligned with the PowerKeeper “7 Ups” security concept, the system integrates:
- 5D alerts (current, voltage, smoke, full temperature monitoring and water immersion detection)
- Triple guard protection at cell, pack and plant level
Together, these features establish a comprehensive cell-to-plant security architecture, enabling early risk detection, accurate alerts and rapid response during daily operations.
Setting a new benchmark in security for C&I energy storage
Passing the UL 9540A cell-module-unit test for PowerKeeper not only provides authoritative validation of system safety performance, but also marks a significant step forward in the advancement of system-level safety standards for the global C&I energy storage market.
As demand for commercial and industrial energy storage accelerates around the world, Sungrow remains committed to providing safe, reliable and intelligent energy solutions, enabling businesses to transition to a more sustainable energy future with confidence.
About Sunrow
Sungrow, a global leader in renewable energy technologies, has been a pioneer in sustainable energy solutions for over 29 years. As of December 2025, Sungrow has installed more than 1,000 GW of power electronic converters worldwide. The company is recognized as the world’s most profitable photovoltaic inverter and energy storage company (BloombergNEF). Its innovations power clean energy projects across the world, supported by a network of 520 service points ensuring an excellent customer experience. At Sungrow, we are committed to building a bridge to a sustainable future through cutting-edge technology and unparalleled service. For more information, please visit: www.sungrowpower.com/en
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