Page | 050 e. Heat flux measurements did not exceed 1.3 kW/m2. The maximum heat flux recorded was 0.0000016 W/m2, which was the sensor installed on the front target MP2 cabinet and was the ambient heat flux the sensor was exposed to throughout the test.
5. Based on a review of the MP2, its fire safety features and the UL 9540A unit level fire test results, the MP2 meets or exceeds all the performance criteria of UL 9540A, Table 9.1 and UL 9540A installation level testing is not required for a MP2 installation.
6. The MP2XL design is almost identical to the MP2 other than being greater in length to accommodate the additional battery modules. Given the limited module propagation observed during UL 9540A unit level testing of the MP2 (seven cells went into runaway) the behavior is expected to be no different with the MP2XL. As such, a stand-alone UL9540A unit level fire test for the MP2XL was not performed. The UL 9540A unit level fire test results, described above for the MP2, can be applied to the MP2XL.
a. Similarly, after reviewing the MP2 unit level fire test results and comparing the MP2 and MP2XL to one another, TÜV determined the MP2 UL 9540A unit level fire test results can be applied to the MP2XL and an additional UL 9540A unit level fire test for the MP2XL was not required for its listing.
7. Smaller capacity MP2/2XL cabinets, populated with less battery modules, would be expected to perform similarly given they are designed and constructed substantially similar (with the same cells, battery modules, fire safety features, etc.) than the larger capacity MP2/2XL cabinets that were tested as described in this report.
8. Additional findings based on the UL 9540A unit level fire test results, are as follows:
a. None of the external fire detectors activated during the fire test (two multi-spectrum IR flame detectors and two thermal imagers). This result is expected, as no flaming was observed outside of the cabinet during the test; however, previous testing by Tesla on the MP1 has demonstrated that multi-spectrum IR flame detectors can detect a fire should
flames exit the cabinet through the thermal roof.
b. An integral fire suppression system or an external fire suppression system is not required
to stop the spread of fire from cell to cell, module to module or MP2/2XL cabinet to cabinet when a near simultaneous failure of up to six cells occurs within the same battery module.
c. Manual fire suppression (hose lines) is not required to stop the spread of fire from a MP2/2XL cabinet to adjacent MP2/2XL cabinets installed 6 in (150 mm) behind and to the sides when a near simultaneous failure of up to six cells occurs within the same battery module.
9. Additional findings based on internal testing and analysis performed by Tesla are as follows:
a. 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 ft upwind
FEI Project # 22035 Page 48 01/23/2023 22035-03R (MP2 and MP2XL FPE Report)
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