Sure, electrical tape is fine. Until it wont fit in your mod, or it gets wet and rolls off, or it just rolls of, because?
Or for $1.60, plus shipping (but you need other stuff to?) you can get 10 wraps and be done with it.
Sorry for being a jerk, but keep in mind that battery is 1/4 stick of dynamite in the WRONG conditions. Just something to think about.