In your battery example, there is no return current path so no current will flow. There is obviously a more deep physics reason for why this works but as the question asked for a simple answer I'll skip the math, google Maxwell's Equations and how they are used in the derivation of Kirchhoff's voltage law.
Maybe something like "Current flow in batteries?" Actually a current will flow if you connect a conductor to any voltage, through simple electrostatics.
During the discharge of a battery, the current in the circuit flows from the positive to the negative electrode. According to Ohm’s law, this means that the current is proportional to the electric field, which says that current flows from a positive to negative electric potential.
Editor’s note, 2/13/2020: Per reader requests, we have uploaded model files to go along with this blog post to the Application Gallery entry “ Potential Profile in Batteries and Electrochemical Cells “. We find out if the electric currents in batteries flow backwards by studying the potential profile inside a battery.
Both effects occur as a battery is drained. The open circuit voltage goes down and the internal resistance goes up. Note that open circuit voltage is specifically measuring just the voltage the battery puts out with the internal resistance taken out of the equation.
When batteries are connected in series, the voltages of the individual batteries add up, resulting in a higher overall voltage. For example, if two 6-volt batteries are connected in series, the total voltage would be 12 volts. Effects of Series Connections on Current In a series connection, the current remains constant throughout the batteries.