Wireless charging battery box

I have a few projects using the Arduino or ESP8266 that transmit data and I use some old laptop battery cells to power them, I had some lying around on the desk and eventually I had an incident where some smoke was released!!!

So I printed some containers to hold the battery pairs in, keeping all the exposed connectors safely covered. I then had the idea to combine the batteries with an old QI wireless charger coil and charging dock to charge the cells by just placing them on the charging pad.

The end cap is supposed to be an interference fit but this one was a bit big (the one in the attached STL is a little smaller so should be OK but not tried it)