Wasferd:
The two components seem rather complex. Is there no simpler solution to breaking a circuit when battery input voltage is lower than a set limit?
Probably not.
Disconnecting a battery below a certain voltage is a particularly complex problem, since the circuit which does this must draw no current once disconnected, but draw no current when connected either as clearly that would actually discharge the battery - the very thing you need to prevent.
This rules out for example Zener diodes as threshold references; the entire circuit must be CMOS.