Definitely tape over it. It's not a huge deal right there because that's negative terminal under there. But, you want to tape it so the rip doesn't spread. When it's really a big problem is when the shrink wrap gets damaged near the top, then you can very easily touch the negative and positive (there's only a really tiny gap between them covered by shrink wrap/insulator) and cause a fire. Since it's there just tape it, keep an eye on it and make sure it doesn't spread and it should be OK.
For anyone else reading this thread, if you get damaged shrink wrap near the top it's absolutely a big deal and be sure to either rewrap it (if you know what you're doing) or toss it (by toss it I mean bring it to a recycling place carefully) and buy a new one if you're not sure.