To recap: the short circuit current is a function of several variables but is mostly determined by the nominal voltage and internal series resistance. If the positive and negative terminals are connected by a wire then the battery is by definition shorted. What the voltage of the battery is does not really matter.
By short circuit we mean an electrical short circuit, a very low resistance path between the positive and negative sides of the cell or cells. A short circuit can be inside a battery cell or external to a battery cell. There are a number of things that can cause an internal short circuit within a battery cell.
A short circuit happens when there is a low resistance path between the positive and negative terminals of a battery, allowing current to flow freely between them. This can happen if the terminals are touching each other, or if something else is connected across the terminals that have a lower resistance than the internal resistance of the battery.
In comparison, the published short circuit current for a single cell is 6,150A. Consider a 2500 Ah cell having a published internal resistance of 0.049mΩ. This battery has 240 cells and the external circuit has a resistance if 21mΩ. The short circuit current is estimated to be:-
For large batteries such as those used in Power Stations, short circuit currents may exceed 40k amperes. Even when the battery is not fully charged, the short circuit current is very similar to the published value because the internal resistance does not vary substantially until the cell approaches fully discharged.
The internal resistance may be used to calculate the theoretical short circuit current but the method used is open to debate. Never the less, values of the internal resistance may be used to estimate the actual short circuit current in a battery system.