Preventing battery damage from road debris

[Raffy.Roma]

To me this looks a good idea. Hope that Tesla will investigate this adaptive front spoiler. IMO main thing would be, in case Tesla choiced to install it on future cars, to advertize it as a mean to get a better aerodynamics and not to avoid road debris.

 

[Raffy.Roma]

A at 55 MPH a steel trailer hitch, pipe, ladder, or Ibeam all would go though that like butter.

But a steel trailer hitch is a very exceptional event. And even in the case of a steel trailer hitch it would be pushed back anyway IMO. Problem would be that the spoiler would get ruined or destroyed.
In fact IMO a steel trailer hitch is so big and heavy that it should be considered halfway between an obstacle and a road debris.
Of course it's much better to have a destroyed spoiler rather than a fire.

 

[VolkerP]

I endorse the idea of an adaptive spoiler. But the main problem IMO remains unaddressed: how to mitigate the serious amount of energy that is released when a piece of road debris penetrates the underbelly of a Model S traveling at speed.
Any deflection or armor will hit the the debris. But only harder.

I suggest an aluminum honeycomb sponge between the front axle and the battery pack.

1. The spoiler will trigger the dangerous upward move of the piece of debris - instead of the battery pack
2. the piece will tilt upward and penetrate the soft honeycomb structure
3. the honeycomb structure absorbs the kinetic energy
4. the piece gets caught in the structure and is dragged along without causing more damage to the car
5. the honeycomb structure allows additional movement of the piece (e.g. driver slams the brakes, making the car nose down)
6. impact sensors signal the driver to pull over.

The honeycomb structure gets replaced in the shop. The piece of road debris can lead to the owner responsible for losing it, and insurance is approached for damage repair costs.

 

[swon]

How about an undercarriage airbag? No seriously, hear me out - Volvo apparently has an exterior pedestrian airbag on their S40:

http://www.cbsnews.com/8301-505145_162-57572794/volvo-adds-pedestrian-airbag-to-v40-model/

Or some other kind of active deflection system. A lot of new convertibles have active rollbars that pop out if you roll over, so why not some kind of plastic or metal deflection system if debris is detected? While I'm not a fan of active systems (I prefer passive rollbars that work 24/7, haha), this might be worth looking into!

 

[LiteWait]

A at 55 MPH a steel trailer hitch, pipe, ladder, or Ibeam all would go though that like butter.

Yeah that is correct in the case of the Porsche. I would hope that Tesla could design one strong enough and with reinforcements that could plow anything out of the way up to 130 MPH.

 

[donv]

I think they'll either remove "Low" mode for the air suspension, or make it be off by default. I'm assuming both were air suspension, is that right?

 

[jerry33]

I think they'll either remove "Low" mode for the air suspension, or make it be off by default. I'm assuming both were air suspension, is that right?

We don't know whether they are air or not. It's assumed they are as most Model S have air suspension.

Removing low mode won't really help as there will be objects higher than the ground clearance. As soon as one of those objects causes a fire then the call will be to set the suspension in high and then very high--and even that won't stop everything. Volker's idea of a honeycomb sponge has the most merit of anything I've read so far.

 

[JRP3]

A higher ride height will reduce the frequency of hits.

 

[jerry33]

A higher ride height will reduce the frequency of hits.

True, but by how much?

 

[Lloyd]

A higher ride height will reduce the frequency of hits.

and at a cost of some of your freeway range.... 5-10%???

 

[FredTMC]

and at a cost of some of your freeway range.... 5-10%???

Let us drivers decide... User selectable please. Plus I'm sure Tesla can publish what range delta is.

 

[JRP3]

I've been trying to find data on the range difference between air and non air cars, can't find anything.

 

[qwk]

I've been trying to find data on the range difference between air and non air cars, can't find anything.

The difference is probably tiny, and I'm not even sure if it's measurable let alone noticeable.

 

[C-NRG-GO]

Why capture it when you can disintegrate it with a laser?

Ha ha, I'm reading along through all these posts and I'm thinking, "Just shoot it with a laser!" Great minds...

 

[Discoducky]

Here's a novel idea: It would seem that the most vulnerable area of the undercarriage is closest to the front of the vehicle. Why not drain the batteries in the front of the battery first and thus reduce the chances for energy discharge and thermal runaway?

 

[JRP3]

They still would have the same amount of flammable electrolyte, and even "drained" they would still have voltage potential and can short circuit. It would also unbalance the pack and cause excessive wear on that module.

 

[woof]

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...)

Semi serious similar suggestion:
Coat the bottom with Teflon. Debris would lift the car which would "slide" right along it, providing nothing on which to catch.

 

[jeff_adams]

It seems to me that all the fires were caused by piercing and not by deformity (plenty of accidents that didn't cause fires). Perhaps Tesla could come up with something that would work like bullet proof glass. There has to be a reasonably priced solution to prevent punctures of the pack.

 

[Lloyd]

The difference is probably tiny, and I'm not even sure if it's measurable let alone noticeable.

If Aero wheels were 3%, I would guess that it is more than that!

 

[Discoducky]

They still would have the same amount of flammable electrolyte, and even "drained" they would still have voltage potential and can short circuit. It would also unbalance the pack and cause excessive wear on that module.

How much more flammable is a fully charged pack vs. a nearly completely discharged pack? Or more to the point. Would a 85kWh pack with 1 mile of rated range be as flammable than a pack with 265 miles of rated range?