[MetalMan]

They come with nickel strips welded to the positive side. The negative tabs are always nickel, so you don't need to worry about those. One must excercise extreme caution when soldering with Lipo. I have gotten a lot of shorts while building the packs, but fortunately haven't had any problems with that. Also, you have to be careful with the heat on the tabs because too much heat can ruin the seal around the tab and basically destroy the cell... You also don't want to bend the tabs too much because they can tear.