does the battery determines the amount of current flowing in the circuit?
Does the battery determine the amount of current flowing in the circuit?


Well... yes and no. The battery will try and give the load whatever it asks for not the other way round. This is true for any voltage source not just batteries (current sources will try and push a set current through a circuit but voltage sources will just sit there and do as they're told).

If the load wants 16.73 micro amps, that's what it will get, if it wants 500mA, that's what it will get. All normal batteries along with almost all power supplies you will normally encounter (except for LED drivers) try only to keep their output at a constant voltage (even if you're drawing 0A, although some ancient PC power supplies go a bit funny with no load).

The problems start when heavy loads are connected to light-duty sources, just like how I'll struggle to lift an 80kg railway sleeper, small power supplies will struggle to maintain their designed output voltage under heavy load.

Everything that isn't superconducting has resistance, everything. Small things generally have more, big currents and high resistances turn into big voltage drops (and lots of internal heating). So if you try and pull lots of current from a small battery, you might find that its output voltage drops right down and keeps dropping until either the load turns off or it stops trying to draw full current. Electronics are not that tough, keep pushing them and eventually they just give up trying (it'll probably get pretty warm too).