Apparatus for diagnosing relay failure of battery using parallel circuit for constant power supply and method thereof

Abstract

Disclosed is an apparatus and method for diagnosing a failure of a relay for a battery required to constantly supply the power to a vehicle with guaranteeing the constant power supply using a parallel circuit. The apparatus of the present disclosure includes a control unit which when voltage and current of a parallel unit is 0 in first state in which a relay unit is in closed state and the parallel unit is in open state, controls into second state in which the relay unit is in closed state and the parallel unit is in closed state, and when the voltage of the parallel unit is equal to voltage of the battery and the current of the parallel unit is 0 in the second state, controls into third state in which the relay unit is in open state and the parallel unit is in closed state, and when the current of the parallel unit is equal to current of the relay unit in the third state, determines a switch of the relay unit to be normal, and when the current of the parallel unit is 0, determines the switch of the relay unit to be faulty, a relay unit through which the current of the battery flows in closed state of the switch to supply the power, and a parallel unit which applies the current of the battery in closed state instead of the relay unit in open state in which the power supply is stopped.