Insulation resistance detecting apparatus, system having the same, and method thereof

A vehicle system comprising:

• a fuel cell configured to supply power;
• a high voltage battery configured to charge and discharge;
• a main delay positioned between the fuel cell and the high voltage battery;
• a first insulation resistance measurement device connected to an output terminal of the fuel cell to measure an insulation resistance value of the fuel cell;
• a second insulation resistance measurement device connected to an output terminal of the high voltage battery to measure an insulation resistance value of the high voltage battery;
• and
• an insulation resistance detection apparatus configured to separate a fuel cell from a high voltage battery based on an insulation resistance value of a vehicle during driving of the vehicle, and to determine whether a failure of the fuel cell is present or a failure of the high voltage battery is present, and when the failure of the fuel cell is present using the insulation resistance value measured when the fuel cell and high voltage battery are separated, to determine a cause of the failure by calculating a variation of insulation resistance;
• wherein the insulation resistance detection apparatus turns off a main relay connected between the fuel cell and the high voltage battery when the insulation resistance value of the vehicle is smaller than a predetermined reference value, and controls the first insulation resistance measurement device to measure the insulation resistance value of the fuel cell.

An insulation resistance detection method comprising:

• separating, by a main relay circuit, a fuel cell from a high voltage battery based on an insulation resistance value of a vehicle during driving of the vehicle;
• determining, by using an insulation resistance measurement device, whether a failure of the fuel cell is present or a failure of the high voltage battery is present by measuring the insulation resistance value of the fuel cell with the fuel cell and high-voltage battery separated;
• and
• determining, by the insulation resistance measurement device, a cause of the failure by calculating a variation of insulation resistance when the failure of the fuel cell is present;
• wherein the separating of the fuel cell and the high voltage battery includes:
• maintaining an open circuit voltage (OCV) state by blocking a stack current of the fuel cell when the insulation resistance value of the vehicle is smaller than a predetermined reference value;
• and
• turning off a main relay connected between the fuel cell and the high voltage battery.