Huawei Digital Power’s Commercial and Industrial Hybrid Cooling Grid Forming Energy Storage System (C&I GFM ESS) has completed an extreme ignition test under the observation of TÜV Rheinland.
This marks what is described as the first ESS fire assessment aligned with the UL 9540A:2025 standard. The test took place at a national key fire safety laboratory and was designed to push system safety to its limits.
To create the most demanding conditions, the assessment used a pack‑level overcharge method to force simultaneous thermal runaway across 60 battery cells. This approach significantly intensifies the challenge compared with tests involving only a small number of cells. Additional severity came from the open‑door ignition method defined in UL 9540A:2025, full 100% state‑of‑charge across all packs, and the disabling of all active and passive fire‑suppression systems.
Huawei’s system demonstrated strong performance through its five‑level protection architecture. This includes inter‑cell thermal isolation to slow propagation, an all‑metal enclosure capable of withstanding temperatures above 1,500°C, and a positive‑pressure oxygen‑blocking design with directional smoke exhaust. A fireproof labyrinth structure across sealing surfaces and reinforced container fire resistance further support system integrity.
Test data showed that when fire temperatures reached 961°C, the highest temperature recorded in an adjacent cell was 45.3°C – remaining below the point at which the explosion‑proof valve would activate. The system met all UL 9540A:2025 criteria, with no fire spread between units, a peak heat release rate of 3MW, and full self‑extinguishing in under three hours.
