Plastic has a certain melting point. as long as the melting point is below the temperature that would damage the battery you should be able to just melt the plastic away. I'm sure it was liquid when it was manufactured with the battery.
but structural battery pack was promising huge weight savings. 4680 SR model Y is almost as heavy as the LR one..we'll see after a few iterations if they take progress. right now it's zero improvement or even worse
Quick check, if volume is 6 times bigger and energy stored is 5.5 times bigger, is energy density higher or lower? Ooh that's right, it's lower. The fact it is structural allows for more capacity to be packed using extra volume that wasn't previously used! If same capacity, higher volume. When will media finally get basic physics?
The new cell-to-chassis EV battery packs will make fixing a bad unit a replacement rather than repair game. Repairability of the new Model Y 4680 structural battery pack is 'essentially zero, according to Cory from Munro & Associates whose teams took two days just to get into the battery.