HEFEI, China, Nov. 27, 2025 — With the increasing adoption of residential energy storage systems, safety has become the paramount concern for homeowners. Any incident in a home environment carries severe implications, and recent accident reports have intensified public apprehension. In response, Sungrow has proactively taken measures to bolster industry confidence and elevate safety standards. Following the successful completion of two full-unit combustion verifications for utility-scale storage, Sungrow has now applied its stringent methodology to the residential sector. The SBH Series: Residential ESS has achieved a significant milestone by being the first worldwide to pass the UL 9540B large-scale fire test, administered by UL Solutions. This accomplishment underscores Sungrow’s leading expertise in managing thermal runaway and controlling fire spread, establishing an unprecedented global benchmark for residential ESS safety.

UL 9540B, specifically tailored for residential energy storage systems up to 20kWh, is widely recognized as the industry’s most rigorous safety standard. The test involves subjecting systems to forced thermal runaway while fully charged, replicating extreme fire conditions, including the accumulation of flammable gases, venting, and external ignition. Its objective is to assess the system’s capacity to prevent fire propagation, explosions, and other secondary hazards. This demanding standard requires superior performance in areas such as system insulation, gas handling, thermal runaway suppression, and overall engineering design.

In adherence to these strict requirements, Sungrow’s SBH Residential ESS successfully endured a challenging 24-hour evaluation. Faced with numerous obstacles—including closely positioned battery units, disabled active fire suppression, continuous ignition sources, and no external intervention—the system demonstrated exceptional inherent safety mechanisms, fulfilling all assessment criteria.

• Containing Fire Spread: Isolating the Risk

The SBH Residential ESS showcased unmatched fire containment during the UL 9540B fire safety test, attributed to a suite of advanced safety features, including cell-level fire-resistant insulation, bottom-mounted heat dissipation, and multi-directional pressure relief. During the test, when one unit underwent thermal runaway ignition, the flames were confined to the pressure relief zone. Adjacent units registered internal surface temperatures of only 21°C—significantly below the 154°C venting threshold—while eave temperatures reached a maximum of 35°C, well under the 150°C limit.

• Self-Extinguishing in 1 Hour: Eliminating Fire at its Source

By utilizing structural designs that enable rapid heat dispersion and thermal isolation between modules, the SBH Residential ESS effectively restricted thermal runaway to the bottom module. Without any active fire suppression, the open flames extinguished on their own within one hour. Subsequent ignition attempts over the following 24 hours resulted in no reignition, illustrating the system’s outstanding safety performance.

• Explosion & Projectile Prevention: Ultimate Safety Assurance

With the active fire suppression system deactivated throughout the testing, the SBH Residential ESS experienced no combustion incidents, explosions, or projectile dangers. The cabinet remained completely undamaged, demonstrating remarkable fire resistance, explosion prevention, and structural integrity.

Building upon its prior success in the UL 9540A Thermal Runaway Fire Propagation Test, the SBH Residential ESS has now successfully completed the rigorous UL 9540B large-scale fire test. This achievement further confirms the system’s comprehensive safety capabilities, encompassing everything from cell-level thermal runaway suppression to full system-wide fire control. Consequently, homeowners can be confident in the SBH Residential ESS’s superior safety performance in actual fire scenarios.

As a global frontrunner in energy storage, Sungrow is dedicated to upholding the highest safety standards within the industry. With a focus on continuous innovation, Sungrow will persist in advancing safety-driven technologies to ensure homeowners can rely on worry-free energy usage, supported by uncompromising protection.

About Sungrow

Sungrow, a worldwide leader in renewable energy technology, has been a pioneer in sustainable power solutions for more than 28 years. As of June 2025, Sungrow has deployed 870 GW of power electronic converters globally. 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 centers ensuring excellent customer satisfaction. At Sungrow, we are committed to forging a sustainable future through cutting-edge technology and unparalleled service. For more information, please visit: .

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