The best servo tape in earth is 3M interior/exterior mounting tape. It is a dense gray form. It sticks like crazy yet releases when you want it to. It also comes off in one piece.

To hold your cells in you need a fiber reinforced strapping tape. You can get 3M 3/4" at the grocery store but that is kinda overkill. Hobby shops sell a 3/8" wide version in black or clear that is better suited for the job.