The Tesla Megapack battery incident at Victoria Big Battery in Australia last year was a learning experience for Tesla and Neoen. The fire occurred in July during the testing of a Megapack. The system was under construction and destroyed two of the 212 Tesla Megapack battery energy storage system (BESS) units being installed.
The fire spread to another battery, destroying the two Tesla Megapacks. The fire lasted six hours, although it was classified as a “safe failure.” The incident was triggered by a liquid coolant leak, according to an assessment conducted by Fisher Engineering and the Energy Safety Response Group (SERB).
This resulted in arcing within the Megapack’s battery modules, which heated the battery modules’ lithium-ion cells, resulting in a propagating thermal runaway event and the fire.
Since it was being tested at the time, the Tesla Megapack that ignited the fire had been manually unplugged from many monitoring, control, and data gathering systems. Wind speed was another aspect that contributed to the spread of the fire. Since this incident, the business has introduced many procedural, software, and hardware mitigations, including better coolant system checks during Megapack assembly, to prevent similar issues from occurring in the future.
Tesla also added new alarms to the coolant system’s telemetry data in order to detect and respond to any coolant leaks. Furthermore, Tesla has fitted specially designed, thermally insulated steel vent shields within all Megapack thermal roofs.
Reference- Energy Storage News, Fisher Engineering and the Energy Safety Response Group (SERB) Report, Clean Technica, Teslarati Article, Sydney Morning Herald