Tesla Megapack fire in Australia did not start from battery modules: analysis

Key Points

• 🔥 A fire occurred in a Tesla Megapack at the Bouldercombe big battery in Queensland, Australia during its commissioning process in late September.
• 🚫 The fire did not start at the Megapack’s battery modules but initially occurred on the AC side of the Megapack unit.
• 🔍 The analysis conducted by Tesla, Genex, and other stakeholders revealed that the fault propagated from the AC side to the battery modules.
• 🛠 Tesla will replace two identified power electronics units and inspect the power electronics in the remaining units to mitigate against potential future events.
• 🚗 The minor fire affected one Megapack battery and caused minor thermal damage to an adjacent Megapack, which will be replaced by Tesla.
• 📅 Replacement Megapacks are expected to arrive at the site in early December 2023.

While undergoing its commissioning process in late September, a fire broke out in one of the Tesla Megapacks at the Bouldercombe big battery in Queensland, Australia. The fire triggered debates about the viability of renewable energy solutions, as well as the safety of battery storage systems. 

The fire was not severe, with Genex Power, the owner of the battery storage system, stating that the fire did not even necessitate the use of water at all. Genex CEO Craig Francis also noted that the isolated nature of the fire suggests that the incident would not have any significant impact on the Bouldercombe big battery. 

And as per an announcement from Genex Power, the fire actually did not start at the Megapack’s battery modules. Instead, the fault initially occurred on the AC side of the impacted Megapack unit. The fault then propagated to the battery modules within the Megapack. This was determined following an analysis of the incident by Tesla, Genex, and other stakeholders.

Genex described the findings of the Megapack battery fire analysis in its announcement: 

“The preliminary RCA indicates that a fault occurred on the AC side of the Megapack unit. The fault then propagated to the battery modules within the Megapack. The burn of the Megapack followed design and certification testing expectations under UL9540A, with no external water required, and no propagation of the active fire to adjacent Megapack units or balance of plant. 

“The failure has been isolated to the power electronics interface with the AC bus bar in the individual Megapack unit itself and not the broader installation of Megapack units. In order to mitigate against a further event, Tesla will be undertaking replacement of two identified power electronics units and out of caution, physical inspection of the power electronics within the remainder of units at the Project site. Genex will also be implementing upgrades to breaker control setting response times to further mitigate against a potential future event,” Genex wrote.

While the minor fire affected one Megapack battery in the Bouldercombe site, the Megapack adjacent to the impacted unit also suffered minor thermal damage to its electrical insulation. Thus, Tesla would be providing two Megapacks to replace the two units that were damaged by the fire. The Megapacks are already en route to the site, and are expected to arrive in early December 2023, as noted in a PV Magazine Australia report. 

Genex Power’s announcement can be viewed below.