I could'nt find proper holder to print for my project, so i draw it myself.
There are five versions to download for a different number of cells in a row (1,2,3,4 and 5), each one has two types (with flat endings, and with guides for an 8mm nickel strip). Holders can be joined together to create a battery pack with desired size.

I recommend to use at least PET-G (better chemical and physical resistance).

Please comment if you notice anything that I can improve.