A hybrid electric vehicle using a high voltage battery includes a system that automatically cuts off (e.g., disconnects) power of a main high voltage battery during an emergency. The emergency indicates excessive electric leakage, insulation breakdown, or the like, due to aging of related components and excessive electric leakage, insulation breakdown, or the like, generated due to a short circuit caused by the destruction of components due to external impact.
When the emergency is generated in a vehicle, an upper component that operates a high voltage component, such as a battery management system (BMS), a hybrid control unit (HCU), or the like, is configured to output a command to cut off a main power to thereby cut off the power. However, since all of the high voltage components are operated while driving during the occurrence of the failure of high voltage insulation-breakdown in a vehicle, it may be difficult to determine which component has failed. In other words, the related art may not accurately determine the defective component and thus may only determine whether the high voltage insulation-breakdown for the overall system of the vehicle is present.
Therefore, when a failure occurs due to the insulation-breakdown, the insulation-breakdown portion may be identified by measuring insulating resistance while sequentially separating and then replacing all of the high voltage components, requiring substantial time and labor force to detect the defective components and an unnecessary incorrect service may also be performed.