Page | 004 5. Internal unit level products of combustion testing demonstrated that HF was only detected at trace levels (0.10 and 0.12 ppm) in two sampling locations (approximately 20 feet upwind and 5 feet downwind from the MP2/2XL) when six cells within MP2/2XL cabinet were forced into thermal runaway. This trace quantity of HF was detected over the entire 21⁄2 hour test duration (i.e., it was the cumulative quantity detected) and is well below the Immediately Dangerous to Life or Health (IDLH) value of 30 ppm for HF. The testing also found no traces of twenty-seven different metals, including lithium and mercury.
6. Internal destructive unit level testing demonstrated that the MP2/2XL is capable of safely failing in the extreme case of a catastrophic failure of a battery module (the forced thermal runaway of 48 cells simultaneously). This destructive unit level test led to a slow progressing fire that burned for 6 hours and 40 minutes until flaming ceased, only consuming one-half of the battery modules in the cabinet.
7. Fire modeling demonstrated that, in the unlikely event of a fire, it would not propagate from one MP2/2XL cabinet to adjacent cabinets installed 6 inches behind, 6 inches to the side and 8 feet directly in front of the initiating MP2/2XL. This result was analyzed for both no wind and worst-case wind conditions where flames could tilt towards the adjacent MP2/2XL cabinets.
8. In summary, unit level UL 9540A testing, destructive unit level testing and a fire propagation model demonstrated that:
a. The MP2/2XL explosion control system can mitigate the deflagration hazard even with
an extreme failure scenario of a battery module (the forced thermal runaway of 48
cells simultaneously) resulting in the MP2/2XL safely failing.
b. An integral fire suppression system or an external fire suppression system is not
required to stop the spread of fire from a MP2/2XL cabinet to adjacent MP2/2XL cabinets when installed at clearances of 8 feet in front, 6 inches behind and 6 inches to the sides.
c. Manual fire suppression (hose lines) is not required to stop the spread of fire from a MP2 cabinet to adjacent MP2/2XL cabinets when installed at clearances of 8 feet in front, 6 inches behind and 6 inches to the sides.
9. Based on a review of the MP2/2XL, its fire safety features, UL 9540A test results, additional internal MP2/2XL unit level fire testing and fire propagation modeling, the MP2/2XL can meet or exceed installation level codes and standards, such as the IFC and NFPA 855, required for outdoor, ground mounted BESS installations when installed in accordance with the MP2 and MP2XL Design and Installation Manual.
FEI Project # 22035 Page 2 01/23/2023 22035-03R (MP2 and MP2XL FPE Report)
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