Question

Condition for which the terminal potential difference of a cell exceed its a emf ??

Answer 1

When we connect a cell to a battery of higher emf than emf of a cell whose direction is opposite to the emf of a cell, then the terminal potential difference of the cell is greater than its emf, because it's direction of current is reversed.
Or you can also say that, when the cell is being charged, the potential difference across its terminals is greater than its emf.
By the relation,

V=E-(-IR)
V=(E+IR)
E+IR>E
V>E