I have yet to get any components, but I printed the dummy battery set.
Wanting to practice more OpenSCAD, I did up the battery compartment so that I can put the connections in place - battery.scad
There are some parameters, but as you can see I got lazy.
I use m3 screws to act as the endcaps and to hold the wire in place
An update: I will be using Supercaps instead of LiPos. Since I haven't got any lipos to play with… I might as well be using a different source