WARNING - Ballistic Evo 2 battery users

[Poodles]

I'm still saying it was install error. If the battery wasn't held down properly and shorted in some way, it's going to fail just like a lead-acid battery would.


This style battery is supposed to not catch fire even if it's punctured, so something else went horribly wrong here.

[stugray]

Originally Posted by Poodles

I'm still saying it was install error. If the battery wasn't held down properly and shorted in some way, it's going to fail just like a lead-acid battery would.


This style battery is supposed to not catch fire even if it's punctured, so something else went horribly wrong here.

I thought about it a little more, and these batteries swell when overcharged/over-discharged.
Some of them will change dimensions a significant amount even under normal usage.
If you tied one of these down TOO tightly (say with a metal band), and then abused it you could expect bad things to happen.

I looked at the photos and this doesnt seem to be the case here (no indentations from hold-downs).

[Poodles]

Originally Posted by stugray

I thought about it a little more, and these batteries swell when overcharged/over-discharged.
Some of them will change dimensions a significant amount even under normal usage.
If you tied one of these down TOO tightly (say with a metal band), and then abused it you could expect bad things to happen.

I looked at the photos and this doesnt seem to be the case here (no indentations from hold-downs).

Had to go to his build thread and find the pic, but here's how it was mounted:



Doesn't look secure enough at all.

[stonenewt]

Originally Posted by Poodles

I'm still saying it was install error. If the battery wasn't held down properly and shorted in some way, it's going to fail just like a lead-acid battery would.


This style battery is supposed to not catch fire even if it's punctured, so something else went horribly wrong here.

There should be all kinds of safe guards, however thermal protection only works so well. We had a incident at work where a Li-Po battery exploded then caught fire. For various, unrelated reasons we had thermal a IR video. It went from about 3C above ambient to bang, then caught fire. Yes there was over-draw, over-load, over-charge & thermal protection on the battery but something in one of the cells obviously just failed causing it to explode. Not a lot you can do about that. I wonder if something similar happened here.

[stugray]

Originally Posted by Poodles

Had to go to his build thread and find the pic, but here's how it was mounted:



Doesn't look secure enough at all.

And if you take into account that the battery can swell/shrink (especially if you abuse it), then it is concievable that the battery moved.

Originally Posted by stonenewt

.. but something in one of the cells obviously just failed causing it to explode. Not a lot you can do about that. I wonder if something similar happened here.

Agreed.
I work with some of the most expensive batteries that you can imagine everyday at work, and there is always the chance that batteries can do nasty things. That's why even mating/demating our batteries is considered a hazardous operation.

[extrashaky]

Originally Posted by stugray

The EXPECTED failure mode of using this battery in the unintended use is that it goes dead, becomes useless, is rendered a paperweight.

The EXPECTED failure mode is NOT = catch fire.

I'm not so sure about that. Don't Fisker Karmas use lifepo batteries? And yet 16 of them spontaneously caught fire after being exposed to seawater during TS Sandy. Do a search and you'll find a number of stories about these batteries catching fire. Perhaps it's not common, but it does happen.

So I don't think you can really say that a fire from a battery in a custom installation being used in an unapproved manner is the fault of the battery or the company that makes it. We know next to nothing about the installation. The Karmas went up because of the seawater. How can you be sure something in the OP's installation didn't expose the battery to a similar unseen and unanticipated fire hazard?

Along those same lines, you keep harping on the overcharge bit, but how do you know that it wasn't overcharged? We don't know whether the vehicle's voltage regulator is a sufficient battery management system for this battery. Being in the car and being charged by an alternator is not the same thing as charging a portable drill or an electric car on a BMS charger. Maybe it was fully charged, and the alternator just kept on pumping power to it, and fffft!

Here's what we do know:

The OP used the battery in a way that is not supported, and even warned against, by the manufacturer.

The OP had a custom installation of the battery.

The battery caught fire.

The OP's own actions make it impossible to rule out installation error or operator error as a cause of the fire.

Therefore, it is also impossible to assign blame for the fire to the battery itself or its manufacture.

Whether it should or shouldn't catch fire really isn't relevant. If you pull a gun on someone to rob him, and he flees from you out into the street and gets run over by a truck, you don't get off the murder charge just because "he shouldn't have done that." The death wouldn't have happened had you not pulled the gun. The battery wouldn't have caught fire had OP not put it in his car.

[stugray]

Originally Posted by extrashaky

Therefore, it is also impossible to assign blame for the fire to the battery itself or its manufacture..

Agreed

Originally Posted by extrashaky

Whether it should or shouldn't catch fire really isn't relevant. .

Yes it is - but my comment was only towards the people who say that this behavior (catching fire) was to be expected because the OP used the battery in a manner that it was not designed for.
I say that catching fire is NOT an expected failure mode for this type of Lithium battery if only overdischarged (what everyone ELSE is assuming caused the problem)

And one thing we have to clarify is anticipated and UNanticipated failure modes.

I work on complex spacecraft for a living. The fault protection in those systems (Like the Fisker or Teslas) build in fault protection for anticipated faults ( I used EXPECTED above).

We clearly cannot protect against all unanticipated faults (like seawater in the system), but we CAN protect against all anticipated faults.
Anticipated faults that are relevant here are overdischarge and overcharge.
In BOTH of those cases, the battery SHOULD have fault protection built in.
The Tesla batteries have thermal switches that should protect individual cells from either of those faults.
IF this battery has those features, clearly they didnt work, or the fault was such that the fault protection features could not prevent the fault.
An example would be a thermal switch in the case of the seawater.
The switch detects the overheating event and opens, but since the current path is no longer through the wiring (it is through the seawater), opening the switch has no effect.

I have experienced spacecraft batteries fail during the shock test because the vendor changed a process.
An insulator that used to be glued down, was not, and repeated shocks caused the insulator to move causing an internal cell short.
The cell exploded (very similar to the pictures above).
This was the fault of the manufacturer not the environment that induced the failure.

Was the battery designed to operate for it's entire life in that shock environment? NO
Was it expected to DESTROY the rest of the system when/if failure occurred? - NO

So the battery failure could obviously been due to an installation error.
And as stated above, if the battery shorts to something, be it a lead-acid, Li-Ion, Li-PO, etc, the results would have been the same whether the battery was properly sized or not.