[Shenzhen, China, December 29, 2025] With full on-site witnessing by DNV, an internationally recognized independent assurance and risk management organization, and TÜV SÜD, a third-party certification body, Huawei Digital Power has successfully completed a large-scale, extreme fire-resistance test of its intelligent string-based grid-forming energy storage system, conducted in accordance with the latest version of UL 9540A.

The test was conducted in strict accordance with the latest UL 9540A standard. A realistic subarray configuration was used, with four mass-produced energy storage units deployed according to the minimum maintenance spacing and safety distance requirements for actual power plants, thereby replicating real-world operating conditions. During the test, four energy storage battery packs were fully equipped and operated at 100% state of charge. The active fire-suppression system of the battery packs was disabled, while the venting windows and doors of Pack A remained open to maximize oxygen intake and promote complete combustion. Simultaneously, thermal runaway was initiated in 16 individual cells via manual ignition, comprehensively validating the system-level thermal runaway propagation mitigation capability and structural integrity under extreme conditions. The results showed that Box A continued to burn for more than six hours (within a 7-hour period) under extreme conditions, with its structural integrity remaining largely intact and the fire not spreading to adjacent boxes, thereby fully validating the system’s overall safety protection capabilities; the cells in the neighboring boxes remained well below their valve-opening temperatures. This marks that Huawei’s intelligent string-based grid-forming energy storage system has demonstrated real-world capabilities to handle extreme scenarios, placing it at the forefront of the industry. On December 15 this year, with full witnessing by UL Solutions, a global expert in applied safety science, Huawei Digital Power successfully completed a venting and explosion-relief demonstration test for its intelligent string-based grid-forming energy storage system, conducted in accordance with the latest edition of the UL 9540A standard. The test thoroughly validated the cabinet’s venting and explosion-relief capabilities as well as the system’s protective performance under extreme operating conditions. This test once again employed a full-door, extreme-fire combustion protocol, adhering to validation criteria that are “more stringent, more realistic, and more systematic.” Such an approach underscores Huawei Digital Power’s unwavering commitment to the safety baseline of energy storage systems, providing a solid foundation for the high-reliability operation and large-scale deployment of energy storage power stations.