18650 Battery storage for ammobox

Disclaimer: I designed this for my own usage. Litium batteries are potentially dangerous and come always with a risk of fire or explosion. You have to decide yourself, if this is a safe way to store them.
Make sure the box is not airtight, preassure which may built up in case of an upheating or leaking battery has to get out of the box, or it could explode! Therefore remove the seal of the lid of the box, or drill 1-2 small holes, for example on the top of the side where they are covered by the lid. (as I did, see pictures)

This holder is made to store 18650 batteries in an 280 x 95 x 175 mm (L x W x H) ammobox. You can order these for example in Geocaching shops, for example this one in Germany: https://geocoinshop.de/Cache-legen/Cachebehaelter-Dosen/Kleine-Munitionskiste::4078.html

There is an top- and an bottom- part. The bottom with round holes are holding the batteries tightly and the top just keeps the batteries in place on the other side. The top- part alone doesnt hold the batteries, make sure to hold it in in place while pushing the holder in the box / getting it out. With the two handles on both parts, you can pull the holder out. Note that possible dents in the metalbox could make it fit tighter / harder to push the holder in or pull out.

You have to print two holders (2x top + 2x bottom). This fits 48 batteries in total.
 

I designed the hight of the holder in the box like this, to leave some space for fire extinguishing granules like these “Fireballs” you can buy in germany as a accessories in model making shops. They are designed to extingluish Lithium-battery fires, but I´m not sure if the available volume of it, would really make a difference in case of an burning battery.
Again: I´m not an expert in this and You have to decide yourself, if this is a safe way to store Lithium batteries. I filled them in a thin plastic tube which you can seal with heat (used for food storage), and made one for the bottom and one for the top of the box.
 https://extron.pichler.de/extron-fireball-brandschutz-feuerloesch-granulat-fuer-lithium-polymer-akkus-pyroballs

The PET recycling logo in the pictures is not part of the STL, I added them in the slicer.

I´m not completely happy with the handles, and may change the design of them. I´m also thinking of designing a version for standing batteries, to take them out separately, but this will fit less of them.