Parametric AA battery box with conventional spring contacts.
Uses cheap contacts available from digikey:
No need to play around with poor contacts, bolts or foil.
Structurally sound, electrically sound, tested and works.
Inspired by: http://www.thingiverse.com/thing:331394
DISCLAIMER: Use at your own risk.
No raft, 5% Infill, Shells = 1
Insert negative and positive contacts, paying attention to where the + is located.
Fit should be tight, use something metal to push contact in.
Solder adjacent negatives solder tags to positives with wire sufficient to take the current required. The last negative and positive, solder a black lead and red lead to respective and route through the center channel out through the side of the holder.
Folder solder tags over into holder so they are flat.
Press fit bottom cover over wiring. If fit is loose, tack glue or use acetone (be careful not to get on the wires, it may melt the coverings).