Victorian Big Battery Caught Fire Was Due to Short Circuit by Coolant Leak

What we already knew about the Victorian Big Battery fire is that it took four days, 150 people, and 30 fire trucks to extinguish it. We still wanted to learn was what caused the fire, but Neoen has been relatively quick in answering that. The blaze started after short circuits “in two particular locations” caused by coolant leaks.
Tesla Says Megapacks Need No Installation: They Would Be Plug and Play 9 photos
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The renewable energy company was elegant enough not to point fingers at its supplier and seemed to share responsibility with Tesla for the whole thing. Neoen mentioned a series of new procedures it would follow in its list of lessons learned to avoid similar incidents. However, the company also said that Megapacks would only be put to work after being thoroughly inspected for leaks.

When we asked Neoen if the leaks were created during the installation process or if the cooling system already comes from Tesla as it should be, the company politely told us to check the “lessons learned” list for the necessary answers. Tesla answered that one for us with its Megapack page. This is what it states (the bold is on us):

“Every Megapack arrives pre-assembled and pre-tested in one enclosure from our Gigafactory—including battery modules, bi-directional inverters, a thermal management system, an AC main breaker and controls. No assembly is required, all you need to do is connect Megapack’s AC output to your site wiring.

Neoen will check for the leaks in “each Megapack cooling system in its entirety” after they are “fully functionally and pressure tested.” In other words, it will not rely solely on Tesla’s pre-tests and will not trust that all it has to do is connect the AC output to the site wiring.

The company also included other safeguards. The SCADA (Supervisory Control and Data Acquisition) system has been changed to “map” in one hour. Neoen will verify it before enabling power flow in Megapacks.

The company also added a new “battery module isolation loss” alarm to the firmware. It automatically removes the Megapack from service when it goes off until Neoen can investigate the cause and fix it.

Neoen also seems concerned with Megapack key lock: it has modified the procedure to use it “during commissioning and operation to ensure the telemetry system is operational.” The company will also make sure the HVC (high voltage controller) that manages the pyrotechnic fuse is still operational when the key lock is isolated.

Finally, Neoen said that Tesla “designers are also working to ensure that Megapacks are engineered to fully mitigate the risk of fire propagation from one unit to another.” The fact that current ones do not achieve that is what killed two Megapacks in the Victorian Big Battery. Those improvements will be “rolled out to Megapacks globally.” That shows the discussion Neoen and Tesla had after the fire must have been a difficult one.


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