I've done plenty of other under-the-hood upgrades. However, I could not get battery unstuck. I used hair dryer to attempt to make the adhesive let go of the battery, but it's a touchy procedure, as you want to loosen glue without melting other plastic components. I slid pryer under side and tried to lift up battery. Ultimately, I must've bent the battery too far, and it combusted! Wrecked iPhone. Not sure why so much adhesive is used. I fear the days of DIY upgrades is winding down, as apple seems to want to use more and more glue and components soldered to the main board, so what you buy is what you're stuck with for the life of the product.
If you can't unstick battery, DON'T pry so much the battery starts to bend! I now wonder if I could've vacuum-sealed the bag and boiled the phone for a few minutes to really warm up the adhesive, but it's an expensive procedure to do trial-and-error on...
Well, at least maybe I can sell the front screen on eBay to recoup some of the cost of a new iPhone...