I have an XPS 9570 that is a few months out of warranty.  It frequently shuts down with no warning, and not during CPU or GPU intensive tasks.  It happens more often when on battery, especially < 50% battery, but it also happens when battery is 100% and power adapter is connected. 

From Event Viewer:

"The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly."