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Discussion Starter #21
I think the difference is the spontaneous nature of the battery fire. The traditional car fire occurs when either the car is in a crash, or when it's operating.
There's also something I didn't think about until recently. With batteries, the ignition source is basically stored in the fuel itself! If you puncture the battery pack, there is a high likelihood that you'll end up with a runaway reaction that includes fire. If you puncture a gas/diesel tank, most of the time you'll "just" end up with a fuel leak and expel your fuel. That is, a gas leak requires a second event: the ignition of the fuel, for there to be a fire.

Now, I do think EVs are safer in that with ICE vehicles, the fuel is being transported through pumps, lines, sprayed into the engine, etc. so there are more potential points for failure. But it's worth noting that any car will be carrying large stores of energy and if you happen to damage the "tank" that holds that energy, I suspect a damaged battery pack is going to ignite more often than a damaged fuel tank.

Mike
 

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Part of the reason batteries are relatively safe is they hold just a fraction of the energy of gasoline; like 2%. If we radically improve energy density in batteries, what will the fires look like?

Batteries also develop dendrites, which are electrically conductive tentacles that can eventually grow until they short the cell and cause a fire. That means that some lithium ion batteries are susceptible to catching fire even if they aren't physically damaged, and might explain some of the seemingly random fires that make the news.
 

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Discussion Starter #23
Yeah, battery safety will have to increase with energy density. I realize this was an unsafe "home build" and isn't indicative of what you'd see in a Tesla but it made me not so much a fan of having a battery pack with 4,400 "bullets" inside. Normally it'd be contained in the pack but imagine what would happen if the bottom side of a Tesla pack got ripped open in an accident or the fire melted through the casing, leaving 4,400 cells to fire off in all directions, starting ancilliary fires:


Mike
 

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I think the difference is the spontaneous nature of the battery fire. The traditional car fire occurs when either the car is in a crash, or when it's operating. The BEV fire has been shown to occasionally occur when the car is at rest. Often for hours. This kind of, parked spontaneous combustion, is exceedingly rare in an ICE car.
Lest us forget the random midnight Ford brake fluid or block heater fires! At least their seat belt and gas tank fires were after crashes.
 

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Here is what I found in the local news, that explosion happened in a Montreal suburb. You can see the pictures and the text is in French, Google translate might be your friend.


 

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Yeah, battery safety will have to increase with energy density. I realize this was an unsafe "home build" and isn't indicative of what you'd see in a Tesla but it made me not so much a fan of having a battery pack with 4,400 "bullets" inside. Normally it'd be contained in the pack but imagine what would happen if the bottom side of a Tesla pack got ripped open in an accident or the fire melted through the casing, leaving 4,400 cells to fire off in all directions, starting ancilliary fires:


Mike
In Tesla's defense, the people in the video did say there was no BMS or battery cooling system attached on these cells. Who knows what happened to start the reaction. Maybe these cells were from a salvaged Tesla pack that were recovered from a severe accident. There are several "salvaged" crashed Tesla's I have seen for sale and it is stated right on Tesla's website that there is absolutely no warranty or service provided on a "salvaged" Tesla unless they do a complete battery inspection (at the owners cost). Apparently they know that the forces of a crash may cause problems much later than after the initial incident.
I am sure glad I didn't buy the salvaged Bolt I was looking at prior to purchasing my used one to save a few thousand dollars...... Another reason to stay away from a salvaged battery electric vehicle.
 

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Discussion Starter #27
In Tesla's defense, the people in the video did say there was no BMS or battery cooling system attached on these cells. Who knows what happened to start the reaction. Maybe these cells were from a salvaged Tesla pack that were recovered from a severe accident. There are several "salvaged" crashed Tesla's I have seen for sale and it is stated right on Tesla's website that there is absolutely no warranty or service provided on a "salvaged" Tesla unless they do a complete battery inspection (at the owners cost). Apparently they know that the forces of a crash may cause problems much later than after the initial incident.
I am sure glad I didn't buy the salvaged Bolt I was looking at prior to purchasing my used one to save a few thousand dollars...... Another reason to stay away from a salvaged battery electric vehicle.
True. I think they simply overcharged them so I suspect spontaneous ignition like that is very unlikely in a Tesla. And the batteries are all in a tray where they can't normally escape like that and fly around.

But... once one cell ignites for any reason, the rest of the pack is likely to go up or at least a good portion of it. I was thinking of a scenario where someone runs over something metal and it rips the Tesla battery pack open on the bottom or it's in an accident where the bottom of the car is damaged and all those "bullet cells" are exposed rather than confined in a tray. At that point, if the runaway starts, the fireworks are likely to begin with flaming rockets firing in all directions. I personally think the pouch packs are safer because they are connected by more than just "zap tabs" at each end. They are not likely to zing off into the air like jumping jacks (fireworks).

Mike
 

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Tesla has re-engineered the battery pack on the Model 3 so they've apparently reduced the potential fire hazard of those packs to effectively zero. From what I've read, there hasn't been a single Model 3 battery fire. Even the model 3 that caught on fire due to the initial garage fire did not result in a runaway battery fire you're describing.
So to clarify the statements above, that may be the case in current Model S or X as a possible scenario, but as Tesla continues to innovate and improve their battery tech, these concerns will become a non-issue as we are seeing with the model 3.
Your initial scenario about running over something and tearing up the pack did actually happen back in 2012 I think, which prompted the armour used under the pack now.
 

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Just a heads up - another Hyundai Kona Electric caught fire in Korea this morning, about 7 hours ago as of this writing. News reports are in Korean, but you can see the photos:


The incident happened while charging at an underground parking lot in an apartment complex in Goun-dong, Sejong-si. FYI, Sejong is special city meant to be the new administrative capital of the country, so most of the government ministries have moved to there. Goun-dong is a residential ward with a lot of apartment buildings.

The charger in question is a common 7kW L2 model deployed in parking lots.
 

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That's troubling considering the Kona is probably sold in relatively low volume, though only 2 fires could still be considered a coincidence, and not an indication of a big problem. The problem I see is that these fires occur when the car is charging, unsupervised, and potentially inside a garage that could catch fire and put people and other property in jeopardy.

Even if the number of fires is relatively low, it's not the type of attention EVs need to gain public acceptance. Hopefully this was either a freak occurrence, or a simple remedy is found.
 

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Some additional info regarding the recent Kona fire have been posted by the owner of the incinerated vehicle in question. The fire happened about 3 hours after the charger has finished charging the car to the preprogrammed setting (90%), cut off the power, and rung up the bill to the owner's credit card automatically. Also, the smoke started to come out from the back of the car first, not the front where the charging circuitry and the motor are. So it may be unlikely that the charger is to blame. It is still unclear why the smoke started in the first place, though.
 

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Just a heads up - another Hyundai Kona Electric caught fire in Korea this morning, about 7 hours ago as of this writing. News reports are in Korean, but you can see the photos:
FYI, I viewed the links using the Chrome browser and it translated the Korean to English for me. It did a pretty good job.
 

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Some additional info regarding the recent Kona fire have been posted by the owner of the incinerated vehicle in question. The fire happened about 3 hours after the charger has finished charging...
Li-Ion battery fires can start very slow and take quite a long time to become obvious, so this shouldn't be taken to indicate that the fire wasn't charging-related.
 

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On a tangentially related note:


If the allegations are true, I'm guessing that the solar installation includes some battery storage which would be the culprit. I can't see any reason why the panels themselves would spontaneously combust. If my theory is true, the root cause might be a failure of cooling fans or some such.
 

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Li-Ion battery fires can start very slow and take quite a long time to become obvious, so this shouldn't be taken to indicate that the fire wasn't charging-related.
True, so it should be interesting to see if the signs of overheating could be traced to more than three hours back (i.e. while the charger was supplying power).
 

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Nothing to do with the car exploding, but I was travelling behind a white Kona EV on the highway yesterday. It looked like a Kona... Would have missed it if I didn't see the word electric or noticed there was no exhaust.
 
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