So some time back there was a thread discussing Tesla's battery patents. Among them was a patent for an intumescent fire retardant (goo). It's layer(s) of material that expand rapidly during heating, thus extracting the heat from the cell and helping quench any fire. It appears that Tesla didn't implement that in the Model S pack, as number of them have been torn down, and although there's glue holding the cells together within the modules, that's it. With the recent Munro & Assoc. teardown, we have some pics inside the pack. Amongst them is an interesting green layer of goo encasing the cells: I wonder if this is possibly an implementation of the patent? It could certainly be different adhesive, but if so it seems interesting that it's also on the tops of the cells (and ostensibly the bottom). It's as if the whole plastic battery module casing assembly has been backfilled with that material.