I think my ESP32 Thing Plus has been fried. I connected a 3.5v (tested on a meter) LiPo battery to the 3v3 and ground pins, and the chip got super hot and appears to be fried now. I checked it by using the USB connection and I was not able to connect to it.
The specs say that it can be powered from 3.0 - 3.6, I believe.
Did I do something wrong here?
LiPo batteries can output up to 4.25 volts, you need to connect the battery to the JST battery connector on the board to properly regulate the battery voltage. Connecting to 3V3 and GND skips all the voltage regulation allowing full battery voltage to be applied directly to the board and potentially frying things. 
Oh, crud - thanks for the info. Guess I misunderstood what the note said about connecting to 3v3.
So if I connect the LiPo to the battery connector (is that the same as the VBAT connection?), can I keep it from trying to charge the battery? I’d rather keep that separate.
As long as you don’t have the battery plugged in while you have a USB cable connected, it won’t try to charge the battery. (The charging circuit gets it’s power from the USB connector.)