Battery deterioration determining apparatus for electric vehicle and method thereof

A battery degradation determining apparatus and method for a vehicle is provided. The method includes charging a battery in a constant current mode to a predetermined voltage and charging the battery in a constant voltage mode when a voltage of the battery reaches the predetermined voltage. A time is measured for maintaining the constant voltage mode from the charger and a degradation degree of the battery is calculated using the measured time for maintaining the constant voltage mode. Accordingly, degradation of a battery is determined quantitatively using a time for maintaining a constant voltage mode in quick charging of the battery disposed within a vehicle.