As residential energy storage systems become increasingly prevalent, safety has emerged as a top priority for homeowners. Any incident in a residential setting can lead to serious consequences, and recent reports of accidents have further heightened public concern. In response, Sungrow has taken proactive steps to strengthen industry confidence and advance safety standards. After successfully completing two real-unit combustion verifications in utility-scale storage, Sungrow has now extended its rigorous approach to the residential sector. The SBH Series: Residential ESS has achieved a significant milestone by passing the world’s first UL 9540B large-scale fire test, conducted by UL Solutions. This achievement highlights Sungrow’s industry-leading expertise in thermal runaway management and fire spread control, setting a new global standard for residential ESS safety.
UL 9540B, specifically designed for residential energy storage systems range from 20kWh and below, is widely regarded as the industry’s most stringent safety standard. The test subject systems are subjected to forced thermal runaway while fully charged, simulating extreme fire scenarios, including flammable gas buildup, venting, and external ignition. Its purpose is to evaluate the system’s ability to prevent fire spread, explosions, and other secondary risks. This rigorous standard demands exceptional performance in areas such as system insulation, gas management, thermal runaway suppression, and overall engineering design.
Against these stringent requirements, Sungrow’s SBH Residential ESS successfully withstood a demanding 24-hour trial. Confronted with multiple challenges—including closely spaced battery units, deactivated active fire suppression, continuous ignition triggers, and no external intervention—the system demonstrated exceptional inherent safety controls, passing all evaluation criteria.
Containing Fire Spread: Locking-In the Risk
The SBH Residential ESS demonstrated unparalleled fire containment during the UL 9540B fire safety test, thanks to a range of advanced safety features, including cell-level fire-resistant insulation, bottom heat dissipation, and multi-directional pressure relief. During the test, when one unit ignited due to thermal runaway, the flames were confined to the pressure relief area. Adjacent units recorded internal surface temperatures of just 21°C—well below the 154°C venting threshold—while eave temperatures peaked at 35°C, far under the 150°C limit.
Self-Extinguishing in 1 Hour: Stopping Fire at Source
By leveraging structural designs that facilitate rapid heat dissipation and thermal isolation between modules, the SBH Residential ESS successfully confined thermal runaway to the bottom module. Without any fire suppression intervention, the open flames self-extinguished within one hour. Further ignition attempts over the next 24 hours resulted in no re-ignition, demonstrating the system’s exceptional safety performance.
Explosion & Projectile Prevention: Maximum Safety Assurance
With the active fire suppression system disabled throughout testing, the SBH Residential ESS experienced no combustion events, explosions, or projectile hazards. The cabinet remained fully intact, showcasing outstanding fire resistance, explosion prevention, and structural stability.
Building on its previous success in the UL 9540A Thermal Runaway Fire Propagation Test, the SBH Residential ESS has now passed the rigorous UL 9540B large-scale fire test. This accomplishment further validates the system’s comprehensive safety capabilities, covering everything from cell-level thermal runaway suppression to full system-wide fire control. As a result, homeowners can have confidence in the SBH Residential ESS’s superior safety performance in real-world fire scenarios.
As a global leader in energy storage, Sungrow is committed to upholding the highest safety standards in the industry. With a focus on continuous innovation, Sungrow will continue to advance safety-driven technologies to ensure homeowners can rely on worry-free energy use, backed by uncompromising protection.
About Sungrow
Sungrow, a global leader in renewable energy technology, has pioneered sustainable power solutions for over 28 years. As of June 2025, Sungrow has installed 870 GW of power electronic converters worldwide. The Company is recognized as the world’s most bankable PV inverter and energy storage company (BloombergNEF). Its innovations power clean energy projects across the globe, supported by a network of 520 service outlets guaranteeing excellent customer experience. At Sungrow, we’re committed to bridging to a sustainable future through cutting-edge technology and unparalleled service. For more information, please visit: www.sungrowpower.com/en.
ENDS.
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