24 volt 280ah compressed..isolated studs...fire

[nonoceb]

Or just do what the rest of us do and stick a sheet of stiff plastic between them.

plastic is not compressible, sikaflex is compressible allowing cell expansion

 

[Short_Shot]

plastic is not compressible, sikaflex is compressible allowing cell expansion

Those of us that are compressing our cells are trying to avoid cell swelling lol

 

[wiseacre]

..and now for something completely different
If you can't prevent a fire - contain it and make maple syrup.

My small maple sugaring arch could handle the heat. Fully lined with full size firebrick with a triple wall stainless chimney that will handle at least the 3rd level of Hellfire.


The 1/8th inch steel plate on top is used to heat the Maple Room (the sugar shed) in winter so we can use it as a sitting room.
During sugaring season there's an evaporator pan with an inch of roiling boiling sap in it.

It would make a hell of a fire safety battery box.
I wonder how many LiFePo4 cells would equal a cord of wood?

 

[Short_Shot]

..and now for something completely different
If you can't prevent a fire - contain it and make maple syrup.

My small maple sugaring arch could handle the heat. Fully lined with full size firebrick with a triple wall stainless chimney that will handle at least the 3rd level of Hellfire.
View attachment 66740

The 1/8th inch steel plate on top is used to heat the Maple Room (the sugar shed) in winter so we can use it as a sitting room.
During sugaring season there's an evaporator pan with an inch of roiling boiling sap in it.

It would make a hell of a fire safety battery box.
I wonder how many LiFePo4 cells would equal a cord of wood?

You can replicate a similar setup with a pile of old drywall and some angle/sheet steel. Would need to be a fair bit thicker though.

That's how cheaper fireproof gun safes are made anyways. Lots of drywall.

 

[nonoceb]

Those of us that are compressing our cells are trying to avoid cell swelling lol

Why using spring in that case, constant pressure compression maybe? lol

 

[Supervstech]

I have been brought into this thread from reports.

I am bothered by the way members are treating each other in this thread.

Why all the arguments focus on the technicalities, and argue that point?

Extinguishing a fire makes sense. Options existing to do so exist. Arguing semantics make no sense…

ANY battery chemistry with Lithium in it is a lithium ion…

The question shouldn’t be why are we discussing lithium ion options, it should be, is this option applicable to LFP…

Don’t make the point pivot on if LFP is Lithium Ion… of course LFP is Lithium Ion… the point needs to be what is best for LFP specifics…

In a Tesla fire, it’s not the car the fire department is concerned about, it is the surrounding area… it is very unlikely in a home battery fire situation, for the house to be in a mall parking lot, or at a school, or other places where an uncontrolled fire breaking out would pose risk to bystanders… so, 30K gallons is the FASTEST containment for that situation… in a house LFP fire… the wiring, and the home, and occupants are the immediate concern…


Best fire prevention for LFP? Fuses. Preventing shorts, and failures from causing combustion temperatures in the wiring… because in a home setup… it’ll be the wiring that starts the fire… protect it at every point.
SOMETHING WILL FAIL. Make sure that WHEN it fails, there is a fuse protecting the wiring from becoming a tinder starter… and make sure as little tinder as possible is available…

Focus people! This forum is about discussion and helping.., not browbeating semantics…

I had to delete a LOT of posts today. Quips are easy… intelligence allows us to discuss topics, or argue pointlessly… I have to delete pointlessness…

 

[Surferdudemi]

Those of us that are compressing our cells are trying to avoid cell swelling lol

There's a nuance here. If you use an insulating layer that compresses at about the force you want to maintain, then as the battery tries to swell, the foam will give only once your target pressure is reached and then exert more pressure until it's flattened between adjacent cells. I think that's what you want, right? And the corners and edges which don't swell as much will not be affected. I.e., the foam would exert the force you want in the areas of the surface where you need it until it's fully compressed (at which point the force would increase a lot more). A hard, non-compressible plastic would not conform to the surface, and would transfer whatever force you're placing on the pack to the points on contact on the surface. That force could be more or less than what you intend, depending upon (a) what state of charge you clamp them at, and (b) whether the pressure is from a spring-loaded rig. If you use a spring-loaded rig, then can't the cells move and put stress on the terminals as some have expressed concern over?

 

[Short_Shot]

There's a nuance here. If you use an insulating layer that compresses at about the force you want to maintain, then as the battery tries to swell, the foam will give only once your target pressure is reached and then exert more pressure until it's flattened between adjacent cells. I think that's what you want, right? And the corners and edges which don't swell as much will not be affected. I.e., the foam would exert the force you want in the areas of the surface where you need it until it's fully compressed (at which point the force would increase a lot more). A hard, non-compressible plastic would not conform to the surface, and would transfer whatever force you're placing on the pack to the points on contact on the surface. That force could be more or less than what you intend, depending upon (a) what state of charge you clamp them at, and (b) whether the pressure is from a spring-loaded rig. If you use a spring-loaded rig, then can't the cells move and put stress on the terminals as some have expressed concern over?

There is a whoole other thread discussing the various methods of compression and their merits. The best seems to be springs but I can't afford the space so I'm using poron foam.

 

[S Davis]

So my question is what is the distortion to the cells from having alternate support between them going to do?

I have mine compressed at 640lbs which is about 11.8psi @ 50%soc and I can see the expansion and contraction in the springs.

I would bet the cells will bulge in those spots stressing the cells even more than them being able to expand and contract as one, all those little bend points between the strips. Maybe the space will keep the pack from being over compressed at 100%soc?

I might be way off base but I wouldn’t do it that way, from what I read over compression is bad too.