I've dealt with two swollen batteries on Dell laptops. Both times the laptop was out of warranty but was in the service window. Dell said that the battery was not a "user serviceable part" and would require me to ship the laptop to them with a estimated 2 week repair turnaround.

I ended up buying a battery on eBay both times along with a screwdriver kit with a T5 star bit (I think that was the size) the first time. It takes about 5 minutes to swap the battery.

I just looked in my email and the seller I used was "good-batteries" but it looks like they don't sell on eBay anymore.