Destructive Fire tests Tesla Powerpack Impressive results

[MitchJi]

https://electrek.co/2016/12/19/tesla-fire-powerpack-test-safety/

The use of lithium-ion battery cells in large energy storage applications is fairly new and the National Fire Protection Association (NFPA) wanted to know more about what would happen if it catches on fire.

Tesla built its Powerpack with safety first in mind and was willing to put its battery system to the test. The company teamed up with NFPA last year and gave them two Powerpacks to set on fire. We got a hold of their test results.
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For the first test, NFPA tried to simulate what would happen if one or several cells within a single pod go into thermal runaway. Will the pod explode? Will it propagate to other pods? Will the entire Powerpack catch on fire or explode? Let’s find out.

They installed a heater cartridge inside one of the modules of a pod placed in the middle of a Tesla Powerpack.

They turned on the heater cartridge, which pushed the cooling system past its limit and while it could be detected that the cells/module was overheating, that wasn’t the goal of the test. They let it hit thermal runaway and the first “popping” sound of cells blowing up was heard after 12 minutes.

After just over half an hour, white smoke started to come out of the pack’s exhaust vent:


That’s gas created from the cells breaking down being evacuated.

The pops were still heard for about 15 more minutes and after it stopped, the smoke started subsiding over 45 minutes.

At 1h30 after the beginning of the test, the smoke stopped coming out of the vent:

Nothing exploded. How boring.

They learned from the test that not only the Powerpack didn’t explode or catch on fire, but the fire created by the heater cartridge didn’t propagate to other pods.

In fact, NFPA found that the 15 other pods were still functional:

They learned from the test that not only the Powerpack didn’t explode or catch on fire, but the fire created by the heater cartridge didn’t propagate to other pods.

In fact, NFPA found that the 15 other pods were still functional:

“Following the test, it was determined that only one of the energy pods (the initiator pod) was damaged. The other 15 pods remained operational and had a full SOC. The energy pods were discharged and the Powerpack was recycled.”

That’s very good news. It means that a Powerpack cannot start a fire since if in the unlikely event that one or a few cells explode, it will be contained within the pod and it will not unleash the entire 100 kWh of energy capacity of the Powerpack.

 

[MitchJi]

Second test:

But what if the Powerpack doesn’t start the fire, but there’s a fire around a Powerpack. Will it explode and aggravate the situation? That’s what they try to figure with their second and more spectacular test.

They installed a propane burner to simulate a constant fire right on the side of the Powerpack.

Here’s the setup:

Nothing was happening for the first ~35 minutes of an intense fire burning on the side of the Powerpack, but then some white smoke started coming out of the vent.

Popping sounds started after 45 minutes.

After 1 hour:...

A sustained flames started coming out of the Powerpack’s back panel at that point.

After hearing pops for a good 15 minutes, they turned off the burner and let the thermal runaway of the Powerpack do the rest from here.

After two hours:
Steady pops are still heard as the 14,000+ cells inside the pack are still exploding.

After 2h30:
While the flames are very strong at this point, the pack itself is not exploding. The pods are encased inside a steel enclosure that prohibits any cell failure from projecting outside and in turn, the steel enclosure of the Powerpack is containing everything while the cells are individually exploding.

After 3 hours:
Fire starts subsiding and the last pop is heard.

After 3h44:

The last visible flame went out and the test was over.

Following the test, they unsurprisingly found out that “all of the energy pods were damaged and there was no stranded energy within the Powerpack.”

NFPA concluded that a prolonged fire outside the Powerpack could definitely induce the Powerpack into thermal runaway, but they found that the consequences were confined to the pack and didn’t propagate:

“However, no violent projectiles, explosions, or bursts (other than a overpressure release of the thermal door refrigerant) were observed during the test while the Powerpack was exposed to the burners, while it was in a free burn state, or after flames were no longer visible. Flames remained mostly confined to the Powerpack itself. Weaker flames emanated from the exhaust vent of the Powerpack, the front thermal door grill, and around the front thermal door seal at varying times throughout the test.”

Most importantly, they determined that the exterior temperatures at the Powerpack cabinet “would not pose a fire spread hazard” if Tesla’s installation standards are respected.

In conclusion, if a fire starts from inside a pod, it doesn’t propagate to the rest of the Powerpack. And if a fire starts outside the Powerpack, it wouldn’t spread to other Powerpacks around it. Of course, there are also several safety features preventing those things from ever happening, but the NFPA’s tests were for worst case scenarios.

 

[Hillhater]

Impressive indeed !
I wonder how they isolate individual modules to contain the thermal propogation between modules ?
Are "Tesla"' cell any less flamable than other brands ?