Not the internal resistance (that can be assumed to stay constant). It's the case of when the load resistance approaches infinity.
The current will fall but, more and more p.d. will develop across the increasing load resistance and less will appear across the internal resistance.
The battery can be modelled by a voltage source (E) in series with a resistor (r) representing its internal resistance.
i.e. the battery terminals will then be as shown by the dotted boundary lines in the diagram.
This is identical to a potential divider:
Where R1 represents the battery internal resistance and R2 represents the load resistance.
If R1 remains constant and R2 increases towards infinity, the equation for the p.d. developed across the load shows that
Vout⇒Vin∞∞⇒VinThis represents the asymptotic limit as the current falls to zero when the load resistance approaches infinity.