Sungrow’s PowerKeeper Achieves Industry-First Triple UL 9540A Certification for C&I Energy Storage Safety
Sungrow Power Supply Co., Ltd. has reached a significant milestone in the commercial and industrial energy storage sector with its PowerKeeper system successfully completing thermal runaway tests across three different levels under the internationally recognized UL 9540A safety standard. The tests—conducted at the cell, module, and unit levels—confirm that PowerKeeper is the first modular DC-coupled commercial and industrial energy storage system (ESS) in the industry to obtain triple-level certification under this rigorous testing framework.
The testing process was independently witnessed by TÜV Rheinland, a globally recognized technical inspection and certification organization. The results demonstrate that PowerKeeper can effectively prevent the propagation of thermal runaway events across multiple system layers. This achievement represents a new benchmark in safety design and validation for energy storage solutions deployed in commercial and industrial environments.
Expanding the Safety Framework for Energy Storage Systems
Energy storage is becoming increasingly essential for businesses seeking to reduce electricity costs, integrate renewable energy, and improve energy resilience. However, safety remains a central concern, especially for installations located in high-occupancy or equipment-dense environments.
Commercial and industrial facilities such as shopping malls, office complexes, hotels, and manufacturing plants frequently require energy storage systems to be installed within limited spaces. These environments often combine human activity, electrical infrastructure, and valuable assets within a compact footprint. In such settings, even a small safety risk can have serious implications.
For this reason, safety standards in energy storage must extend well beyond simple compliance requirements. The central challenge is not merely managing fire incidents but preventing them from escalating in the first place. Thermal runaway—an uncontrolled increase in temperature within a battery cell—is one of the primary safety concerns in lithium-based energy storage technologies. If a runaway reaction spreads from one cell to neighboring cells, it can potentially trigger cascading failures across an entire battery system.
This is where the UL 9540A testing methodology plays a crucial role.
Understanding the UL 9540A Benchmark
The UL 9540A standard is widely recognized as the global benchmark for evaluating the fire propagation and thermal runaway risks associated with energy storage systems. It provides a structured testing methodology designed to assess how battery systems behave when thermal runaway is intentionally triggered.
Traditionally, many energy storage manufacturers validate their products by conducting tests at only one level of the system architecture. Some focus exclusively on cell-level testing to understand basic thermal parameters, while others emphasize module-level or system-level evaluations.
Although these tests provide useful insights, they do not always capture the full picture. Energy storage systems consist of multiple layers of safety architecture, and evaluating only a single level can leave gaps in understanding how thermal events propagate throughout the system.
Recognizing this limitation, Sungrow adopted a comprehensive approach with PowerKeeper by conducting UL 9540A tests at three distinct system layers: cell, module, and unit. This method establishes a complete safety validation framework rather than isolated compliance checks.
Creating a Multi-Layer Safety Validation Chain
PowerKeeper’s triple-level certification forms a complete evidence chain that demonstrates safety performance across every stage of the system architecture.
At the cell level, the testing captures the key thermal parameters associated with runaway reactions. These tests determine how and when thermal runaway begins and how the cell’s safety mechanisms respond to extreme conditions.
At the module level, the evaluation focuses on the ability of the battery pack to contain a thermal event. In other words, if a single cell experiences thermal runaway, the test verifies whether the surrounding cells remain unaffected.
Finally, unit-level testing assesses whether a thermal incident within one cabinet can spread to neighboring cabinets or surrounding infrastructure. This level of validation is particularly important for real-world installations where multiple cabinets are installed in close proximity.
Together, these layers provide a holistic safety framework that ensures the system can maintain structural and operational integrity even during extreme scenarios.
Simulating Real-World Installation Conditions
One of the most notable aspects of the testing program is that it replicated realistic installation constraints rather than ideal laboratory conditions.
In commercial and industrial facilities, space is often limited. Energy storage units are frequently installed near walls or placed close to one another in order to maximize available space. Such configurations require careful validation to ensure they do not increase safety risks.
During PowerKeeper’s unit-level testing, the system was installed with only 25 millimeters of clearance from a wall and 450 millimeters between adjacent cabinets. These distances closely mirror real-world deployment conditions.
Under the test scenario, thermal runaway was intentionally triggered within one battery cell. The affected cell reached a peak temperature of 595.2°C, representing a severe and highly demanding test environment.
Despite the extreme temperature within the triggered cell, PowerKeeper successfully demonstrated exceptional containment performance.
No Impact on Neighboring Cabinets
Even with only 450 millimeters of separation between cabinets, the adjacent energy storage unit recorded a maximum surface temperature of just 13.7°C. This is significantly lower than the 141.3°C threshold specified by UL 9540A for safe operation.
The results confirm that thermal energy from the triggered unit did not propagate to nearby equipment.
Minimal Wall Temperature Increase
Similarly, the wall located only 25 millimeters from the tested unit experienced a temperature increase of just 29°C, which is far below the 97°C limit established by the safety standard.
This demonstrates that PowerKeeper can safely operate even when installed very close to building structures.
Module-Level Safety: Containment Without Combustion
At the module level, engineers intentionally triggered thermal runaway in three individual cells within the battery module.
Even under these controlled but extreme conditions, the system showed no signs of combustion or explosion. Additionally, there was no external debris, splashing, or material ejection, which are potential hazards often associated with uncontrolled thermal events.
The results confirm that any thermal reaction remains fully contained within the battery pack itself. This containment capability is essential for preventing cascading failures across larger energy storage installations.
Cell-Level Protection: Controlling the Event at Its Origin
The cell-level tests focused on the earliest stage of a potential thermal runaway event. During the evaluation, the battery cell’s explosion-proof safety valve activated immediately once internal pressure reached a critical threshold.
This valve released internal pressure in a controlled manner, preventing combustion or explosion. The tests also captured the exact trigger temperature for thermal runaway, which was measured at 216.3°C.
By precisely managing pressure release and thermal behavior at the cell level, the system adds another layer of defense against propagation.
Moving Beyond Passive Safety
While the UL 9540A tests confirm the system’s ability to contain extreme events, Sungrow has also integrated a comprehensive set of active safety technologies to protect everyday operation.
These features align with the company’s “7 Ups” safety design philosophy for PowerKeeper.
One key element is a 5D monitoring and alert system, which continuously tracks several critical parameters including current, voltage, smoke presence, full-stack temperature conditions, and potential water immersion. By monitoring multiple operational variables simultaneously, the system can detect abnormal behavior at a very early stage.
In addition, PowerKeeper employs a triple-guard protection architecture that spans three system levels: the battery cell, the battery pack, and the overall plant.
This layered protection strategy enables rapid detection, accurate warnings, and fast intervention whenever potential issues arise.
Raising the Bar for C&I Energy Storage Safety
The successful completion of triple-level UL 9540A testing represents more than just a certification milestone. It establishes a new model for how safety should be validated in commercial and industrial energy storage systems.
As energy storage adoption accelerates worldwide—driven by renewable energy integration, rising electricity demand, and the need for grid flexibility—ensuring safe operation is becoming increasingly important.
PowerKeeper’s comprehensive testing program demonstrates that it is possible to achieve robust safety assurance through both passive containment design and intelligent monitoring systems.
For Sungrow, the achievement reinforces its commitment to delivering energy storage solutions that combine performance, reliability, and advanced safety.
As businesses around the world continue to adopt energy storage technologies to support decarbonization and energy resilience, systems like PowerKeeper provide the confidence needed to deploy these solutions even in complex and space-constrained environments.
By setting a new benchmark for multi-layer safety validation, Sungrow’s latest achievement marks an important step forward for the entire commercial and industrial energy storage industry—and for the broader transition toward a safer and more sustainable energy future.
Source Link: https://www.sungrowpower.com/
