Well, I don't know since I rarely let my battery get below about 30%. Many things won't work if they are plugged in with the battery missing, as the connection thru the battery is a part of the circuit (even if it's dead or nearly so). Once you completely remove the battery you have an open circuit.
I know that my motorcycle, and most cars work that way, as well as many cell phones and other items. I can confirm that the Evic won't vape without the battery, even if plugged in because I just took the battery out of mine. The screen says "Charge Completed" even though the battery is gone and it is plugged into the USB.