ORIGINAL: Campgems
An important thing to keep in mind is that the solder tabs will not hold up of movement of the cels for very long. A good heat shrink covering is a must. If the batterys can wiggle around in the pack, the tabs are going to fail. I know from experience.
If/when I build my own packs I will also lay down a bead of hot glue between each cell to keep the pack together and not wiggle. I then heat shrink the entire pack.
Ken