# battery box material



## sokon (Sep 15, 2011)

Hi all,

Has ever anybody build a battery box out of this kind of material:

http://www.habegger-ceramics.de/41822/41913.html

Site is in german, main points about the material are:

1. extremely heat resistant
2. very good heat insulation (see table at the bottom)
3. robust
4. very light (270kg/m^3)

I am thinking of using such a material to build a battery box, after all it lets me sleep better when I know that the worst case scenario is a lost battery pack and a garage full of smoke (instead of a burnt down house^^).

best,
sokon


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## DJBecker (Nov 3, 2010)

Is thermal insulation really desirable?

All types of batteries generate significant heat during charge and discharge. If your battery box is too well sealed, you'll need forced air cooling. That provides the opportunity for active thermal control, at the expense of complexity and more things to go wrong.


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## sokon (Sep 15, 2011)

why not?

In case of fire it will make the generated heat to exit the battery box slowly... that is desirable I think.


Edit: For normal use (whwn there is no fire^^) you are right!


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## Rational (Nov 26, 2011)

The lowest charring temp. I could find here is 120C
http://www.tcforensic.com.au/docs/article10.html

If the battery surface gets hotter than this I'd recommend forced air cooling to preserve battery life and an insulated container such that the outside surface of the container never gets above 120C in the max. ambient temp., let's say 30C.
If the container has fins you can get some convection cooling.

I s'pose battery lifetime halves with each 10C increase in temperature, as with the speed of many chemical reactions.

Once you know the R value for the box material this all can be worked out on paper and then confirmed in practice.


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## Salty9 (Jul 13, 2009)

Anyone see the Mythbusters program where they were abusing/misusing pick-up bedliner? It looked like it could be useful for coating battery boxes.


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## dtbaker (Jan 5, 2008)

I built original battery boxes with 1/4" polypro plastic... and a steel rail exoskeleton.... worked great. polypro is acid resistant, fairly stiff, not too heavy, easy to work with and heat-weld.

visit site for details if desired....


next time I will go with aluminum rails to avoid painting and make lighter.... strength and acid not an issue with Li batteries like lead.


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## TexasCotton (Sep 18, 2008)

I have notice some "builds" and "kits" use metal/stainless steel for battery box materials. The one I have in mind is the PHEV kit by Engineer which uses stainless steel material and completely encapsulates. Personally, I do not care for the stainless steel battery box material. I think different materials would work better for example fiberglass, clear rigid flat plastic, fiberboard, alumin, and/or a mix thereof.


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## dtbaker (Jan 5, 2008)

TexasCotton said:


> I have notice some "builds" and "kits" use metal/stainless steel for battery box materials.


I'd agree.... aluminum diamond-plate looks great, but I just don't like the idea of all that conductive material anywhere near battery terminals that could potentially short with a dropped wrench or whatever.

At the very least I would suggest lining with plastic anywhere near the terminals/lid


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