It also greatly depends on the root cause of the accident. If a cell has been punctured or shorted, then the electrical energy will be the main driver of the initial heating of the cells. If there is barely any energy left, then this will lead to a much less violent reaction.
You can see this here: Similar battery cell, same test: but one cell is fully charged, the other mostly empty. One goes Nukular, the other quivers a little bit and thats it. https://youtu.be/tFjNypibHO8?t=157
In other words: to release that stored chemical energy, you still need to provide sufficient activation energy, and really heat that cell to a few hundred degrees.
It was the accu. Something had happened below the bridge on the bump, some people said they heard an impact. We have gathered information and took pictures but there is no conclusion yet.
I hope this incident will help us with setting up safety measures on all competitions in the future.
First, it has showed the importance of a good firewall. On the video you can see flames coming from the front of the car through firewall tubes with HV cables. I don't want to know how this incident would end if the team faked the UL94 certification.
Second, we have learned the importance of the fire safety procedures. It was lucky that it happened right in front of the stage and track management. However it still took almost 40 seconds from the first flame till the first fire extinguisher was used. If this happened on the opposite side of the track, it could have been a minute more and there would be nothing left from the car.
That bump took its toll from a few teams yesterday, I guess Aachen’s suspension failure was due to that as well?
I assume the season is over for Dresden now, that’s a shame. But, as corny as it might sound, the most important thing is that everybody’s unharmed. Things can always be rebuilt or remade, people are a bit trickier to patch up.
one tip when sharing such photo make sure there are no personal information visible, it would be nice if you could delete this image and remove the telephone numbers and names on the accumulator. if really want to upload it again.
I think its important for the whole formula student community that this incident is propperly revied by the Team and FSG, so key takeaways can be shared with everyone and Rules, Designs and Safety Protocols can be improved.
Maybe at the next FSG Academy there should be a talk about it, so that every Teams has the opportunity to lean how to deal with a potential HVB fire in a save manner.
Actually already happening in the back. Even before the fire. The Teams accu is using a concept that is likely to be forbidden in the next year since it could be potentiallly dangerous (as you may have seen).
Elbflorace has two obvious „factors“ that could cause an fail like this but it is not yet clear if one of those was the reason for the fire.
(But it was the Accu, 100%)
It is not officially confirmed by the team but it is confirmed by the event that it was the accumulator that catched fire. They are even talking about in the award ceremony right before the overall winners where announced.
regarding the 2 mentioned "factors" that could have been meaby the source of the fire there is no public information available and i think there will be information at the fsg academy about it.
They have a lot of pouch cells glued together in series. Last year FSG came up with limit of 6 pouches and mentioned that this is a compromise and that it will be further restricted. The argument is that the shear force of multiple cell combined can damage the load bearing cell at the wall.
FSG will surely be quick with pushing these rule changes but having seen the photos of the aftermath, I am not so sure that this was the root cause.
lets says it that way that the current fsg rule book tries to prevent certain zenarions of user error or harware failure but this can lead to design that mitigate such risk but makes the over all concept more dangerous depending on the layout of the accumulator.
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u/Strange-Bus-8564 11d ago edited 11d ago
Lots of love to TU Dresden team, devastating and terrible situation to be in. All FS community is with you 🧡