Have you tried to power the board with a power supply? Maybe its just a small capacitor, thats causing a short on a line. The Ic can get hot because if you add the charging cable some current ist going through the ic towards the short. But thats just a guess. Best way is to give around 4v to the battery connector, check the current for a short and then find on what line the short ist (instant short means on a main power rail, so check them in diode mode). Then you can give voltage to the shorted line and check what component is getting hot now. If its still the ic, you need to replace it.