UL 9540A Test Report for R-Bracket Battery Unit

This test report evaluates thermal runaway fire propagation in the R-Bracket battery energy storage system (BESS) unit according to ANSI/CAN/UL9540A:2019. The unit, manufactured by Shanghai PYTES Energy Co., Ltd., uses LiFePO4 chemistry with a nominal voltage of 51.2 V and capacity of 100 Ah per module. Testing was conducted at SGS-CEC New Energy Technology in Chongqing, China, from July to August 2022. Results show that thermal runaway was contained by the unit design, with no external flaming, flame extension, flying debris, or explosion observed. The maximum surface temperature of the module in the target BESS unit reached 158.1°C, and the maximum temperature rise on wall surfaces was 94.3°C. The cell vent gas was found to be flammable, but the cheesecloth indicator showed no flaming or carbonizing. The report updates previous versions to include UL 9540 compliance certifications. Overall, the R-Bracket unit demonstrates effective containment of thermal runaway events, meeting the requirements of the UL 9540A standard for unit-level fire propagation testing.