JRP3
Hyperactive Member
One thing to note is the LEAF pack leading edge starts about a foot or so behind where the S pack starts. It's also a higher riding vehicle I believe.
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Preventing battery damage from road debris
- Thread starter wcalvin
- Start date
I posted the same question in the other thread, but I'll pose it here, too: is there something about Leaf pack chemistry that would make it immune to fire if you deliberately pierced it with a metal object?
Just curious about whether the difference is in body and chassis design, or in pack chemistry.
Just curious about whether the difference is in body and chassis design, or in pack chemistry.
One idea to mitigate the risk from road debris would be an easily accessible button that would disengage "Low" suspension mode and raise the car immediately even at highway speeds. I like this idea better than simply eliminating the lowest setting permanently. It could be the hazard lights button that activates this feature.
Well not necessarily immune, but the Leaf battery is significantly less flammable than Tesla's pack. However, the Tesla chemistry has much higher energy density per cell which is why we all get much better range.
Well not necessarily immune, but the Leaf battery is significantly less flammable than Tesla's pack. However, the Tesla chemistry has much higher energy density per cell which is why we all get much better range.
Probably not the worst thing though. While it is great to know it's not difficult to swap the battery when necessary, I have always wondered if the complexity of administering a battery swap program as a convenience is really worth it in the long run (and shouldn't they be focusing more on the build-out of SC network)? Dunno, just a question.
omgwtfbyobbq
Active Member
I agree. Additionally, this would allow the aluminum plate to deflect more instead of puncturing. That, plus a cow catcher, would probably eliminate the majority of pack fires caused by foreign objects.
Of course, the downside would be slightly higher cost and lower range from either reduced battery size or greater vehicle height/drag, but the car already has excellent range and is very expensive, so I don't think that's an issue.
The battery swap was nothing more than an idea. The public demo was for ZEV credits. There was never a plan to make this a real offering. Not one swapping station has been built. So this is completely irrelevant.
JRP3
Hyperactive Member
I believe it's a non cobalt oxide chemistry as well as being a less energy dense chemistry, so both would lower the potential energy release, but any shorted cell can potentially put out high current and cause a fire.
Not necessarily, the swap system only needs access to the bolt holes, which need to be accessible for pack installation at the factory anyway. No reason you can't reinforce the plating and leave swap capability unaffected.
swaltner
Active Member
Bose active suspension - YouTube was posted on mynissanleaf on the discussion of the fires and options for avoiding trouble. Jump to 1:40 for one option of preventing damage to vehicles.
Owner
Active Member
What about a simple solution: keeping a longer distance from the car in front of you?
When I drive on the freeways it always seems like everyone likes to be in a pack. I do my best to somehow get away from the group. Not really for road debris, but I just would rather have the open road.
I am not saying that the three Tesla fires were caused by tailgating but the less tailgating the better in my book.
When I drive on the freeways it always seems like everyone likes to be in a pack. I do my best to somehow get away from the group. Not really for road debris, but I just would rather have the open road.
I am not saying that the three Tesla fires were caused by tailgating but the less tailgating the better in my book.
IMO This likely will not happen as long as there are people...oh, and driving. In addition, many have shared experiences where debris is deflected into your path not from "dead ahead". Even with a "good" following distance, it is not always within your control. I've had it happen to me but just thankfully not substantial enough debris for this kind of result in any car yet.
Correct. I didn't say anything about the likelihood of it ever happening
Me too. I have a couple of gouges in the paint armour from debris being kicked up by cars traveling in the opposite direction.
Correct, good following distance just reduces the chances of it happening. No technique can prevent every occurrence.
JakeP
S P4996 ==> P02547
Yes it is not always preventable. I have had a truck shed a tire in front of me when I was trapped between two jersey barriers in a single lane, driving a tiny and low-to-the-ground Boxster. Nothing I could do but straddle it and hope for the best. Fortunately it didn't get hung up on anything, and damage was only cosmetic and easily repaired.
Nice to see a few replies that are serious contributions.
Tesla has made a few design mistakes, in the midst of many excellent design decisions. Remember the early hoods that were too thin? Now it is looking like the exposed location of the battery pack was not mitigated by enough armor to withstand lever-aided punctures.
The rear wheels are about where the lowest clearance occurs. The front bumper bottom looks to have about the clearance of the forwards part of the battery. That means that the energy storage container is almost guaranteed to take the hit for any object whose height falls between the two clearances.
So far, the armor has handled gouges from trailer hitches--the ones that did not pop up from leveraging. No fires, at least. But the two fires from road debris show that the protection is insufficient. Car handling and occupant safety has remained okay, but the delayed fires are spectacular enough to trigger concern.
I expect that some engineer pointed out the battery vulnerability to road debris during the design phase but the comment got lost. Looking good and underside aerodynamics are good arguments for the approved design, but now it is starting to look like a design mistake. After all, if someone had proposed a flat (but armored) gas tank covering the bottom of the car, the idea would have been shot down quickly. (It's a worse situation, gasoline vapor at the same time as sparks.)
Fortunately, some sort of shield under the front bumper might handle the Model S problem. It is the same principle as an outer defense line out in front of the armored protection for the vulnerable stuff.
Tesla has made a few design mistakes, in the midst of many excellent design decisions. Remember the early hoods that were too thin? Now it is looking like the exposed location of the battery pack was not mitigated by enough armor to withstand lever-aided punctures.
The rear wheels are about where the lowest clearance occurs. The front bumper bottom looks to have about the clearance of the forwards part of the battery. That means that the energy storage container is almost guaranteed to take the hit for any object whose height falls between the two clearances.
So far, the armor has handled gouges from trailer hitches--the ones that did not pop up from leveraging. No fires, at least. But the two fires from road debris show that the protection is insufficient. Car handling and occupant safety has remained okay, but the delayed fires are spectacular enough to trigger concern.
I expect that some engineer pointed out the battery vulnerability to road debris during the design phase but the comment got lost. Looking good and underside aerodynamics are good arguments for the approved design, but now it is starting to look like a design mistake. After all, if someone had proposed a flat (but armored) gas tank covering the bottom of the car, the idea would have been shot down quickly. (It's a worse situation, gasoline vapor at the same time as sparks.)
Fortunately, some sort of shield under the front bumper might handle the Model S problem. It is the same principle as an outer defense line out in front of the armored protection for the vulnerable stuff.
JRP3
Hyperactive Member
My Fiero had a gas tank running down the middle of the vehicle, no protection at all. My RAV4 has two tanks on either side of the drive shaft, no protection. Neither vehicle has a tank covering the entire underside, but they are indeed exposed and vulnerable.
This is an email that I have been sending to as many people as possible for the past 2 weeks after another incident that did not result in a fire. I was told to post it here by Doug:
I saw another person on the forums that ran over some road debris which caused significant damage to the battery pack. In this instance, the road debris was low enough to miss the bumper but high enough to hit the battery pack. Thankfully the battery did not catch fire. If the road debris had been any larger I think it certainly could have.
The problem is that the fixed bumper on the Model S needs to be higher than the bottom of the battery pack so that the car can approach steep inclines such as a driveway or parking garage without causing excessive damage. With the front bumper being higher than the very bottom of the battery pack by an inch or two anything that falls within this difference can be run over by the car, bypassing the bumper and making impact with the battery. Although the instances of this would statistically be rare, they will occur more often as more cars hit the road.
The solution is simple and Porsche is already doing it with the all new 2014 911 Turbo:
http://www.youtube.com/watch?v=BrDS3G4U8yM
@ 2:20 http://www.youtube.com/watch?v=1iCsjdHqz60
It is an adaptive front spoiler and all Tesla cars should come with it as standard. Tesla can market this feature as performance enhancing without having to raise an eyebrow that it is also inherently a cattle guard like one would find on a train to keep it from derailing. If this is deployed at highway speeds to a height below the bottom of the battery, it would clear away any debris that might otherwise inflict damage to the battery pack. Another benefit obviously is that if the car does hit any debris in the road and damages the front spoiler it would be a lot cheaper to replace than the battery pack.
I saw another person on the forums that ran over some road debris which caused significant damage to the battery pack. In this instance, the road debris was low enough to miss the bumper but high enough to hit the battery pack. Thankfully the battery did not catch fire. If the road debris had been any larger I think it certainly could have.
The problem is that the fixed bumper on the Model S needs to be higher than the bottom of the battery pack so that the car can approach steep inclines such as a driveway or parking garage without causing excessive damage. With the front bumper being higher than the very bottom of the battery pack by an inch or two anything that falls within this difference can be run over by the car, bypassing the bumper and making impact with the battery. Although the instances of this would statistically be rare, they will occur more often as more cars hit the road.
The solution is simple and Porsche is already doing it with the all new 2014 911 Turbo:
http://www.youtube.com/watch?v=BrDS3G4U8yM
@ 2:20 http://www.youtube.com/watch?v=1iCsjdHqz60
It is an adaptive front spoiler and all Tesla cars should come with it as standard. Tesla can market this feature as performance enhancing without having to raise an eyebrow that it is also inherently a cattle guard like one would find on a train to keep it from derailing. If this is deployed at highway speeds to a height below the bottom of the battery, it would clear away any debris that might otherwise inflict damage to the battery pack. Another benefit obviously is that if the car does hit any debris in the road and damages the front spoiler it would be a lot cheaper to replace than the battery pack.
A Solution to Road Debris
This is an email that I have been sending to as many people as possible for the past 2 weeks after another incident that did not result in a fire. I was told to post it here by Doug:
I saw another person on the forums that ran over some road debris which caused significant damage to the battery pack. In this instance, the road debris was low enough to miss the bumper but high enough to hit the battery pack. Thankfully the battery did not catch fire. If the road debris had been any larger I think it certainly could have.
The problem is that the fixed bumper on the Model S needs to be higher than the bottom of the battery pack so that the car can approach steep inclines such as a driveway or parking garage without causing excessive damage. With the front bumper being higher than the very bottom of the battery pack by an inch or two anything that falls within this difference can be run over by the car, bypassing the bumper and making impact with the battery. Although the instances of this would statistically be rare, they will occur more often as more cars hit the road.
The solution is simple and Porsche is already doing it with the all new 2014 911 Turbo:
http://www.youtube.com/watch?v=BrDS3G4U8yM
@ 2:20 http://www.youtube.com/watch?v=1iCsjdHqz60
It is an adaptive front spoiler and all Tesla cars should come with it as standard. Tesla can market this feature as performance enhancing without having to raise an eyebrow that it is also inherently a cattle guard like one would find on a train to keep it from derailing. If this is deployed at highway speeds to a height below the bottom of the battery, it would clear away any debris that might otherwise inflict damage to the battery pack. Another benefit obviously is that if the car does hit any debris in the road and damages the front spoiler it would be a lot cheaper to replace than the battery pack.
This is an email that I have been sending to as many people as possible for the past 2 weeks after another incident that did not result in a fire. I was told to post it here by Doug:
I saw another person on the forums that ran over some road debris which caused significant damage to the battery pack. In this instance, the road debris was low enough to miss the bumper but high enough to hit the battery pack. Thankfully the battery did not catch fire. If the road debris had been any larger I think it certainly could have.
The problem is that the fixed bumper on the Model S needs to be higher than the bottom of the battery pack so that the car can approach steep inclines such as a driveway or parking garage without causing excessive damage. With the front bumper being higher than the very bottom of the battery pack by an inch or two anything that falls within this difference can be run over by the car, bypassing the bumper and making impact with the battery. Although the instances of this would statistically be rare, they will occur more often as more cars hit the road.
The solution is simple and Porsche is already doing it with the all new 2014 911 Turbo:
http://www.youtube.com/watch?v=BrDS3G4U8yM
@ 2:20 http://www.youtube.com/watch?v=1iCsjdHqz60
It is an adaptive front spoiler and all Tesla cars should come with it as standard. Tesla can market this feature as performance enhancing without having to raise an eyebrow that it is also inherently a cattle guard like one would find on a train to keep it from derailing. If this is deployed at highway speeds to a height below the bottom of the battery, it would clear away any debris that might otherwise inflict damage to the battery pack. Another benefit obviously is that if the car does hit any debris in the road and damages the front spoiler it would be a lot cheaper to replace than the battery pack.
Norbert
TSLA will win
Maybe lots of rolls underneath. So if something is small enough to get below the car, instead of giving resistance, the battery will just roll over it. (Not sure if this qualifies as a serious suggestion...)
