Car turning off while driving

Does anyone have any idea what the problem could be. The past few weeks, i have been having problems with my battery cable wires and one keeps getting loose. So all i do is tighten them. i am about to switch them out, but today, as i was getting to work, the car turned off and put it on park and then started it again and died out, then i tried it again and it started and i was able to get to work. What could this problem be?

the car should still run with the battery cables coming of the alternator gives the car power while running