Circuit for protecting battery for electric vehicle and driving method thereof

Abstract

A circuit for protecting a battery for an electric vehicle includes a high voltage battery configured to output a DC voltage, an inverter configured to selectively receive the DC voltage from the high voltage battery and invert the DC voltage into an AC voltage when the inverter receives the DC voltage, a relay disposed between the high voltage battery and the inverter and configured to selectively block the DC voltage from the high voltage battery to the inverter, and a battery management system including a microchip configured to output a main relay control signal for controlling the relay. The battery management system is configured to receive the DC voltage from the high voltage battery, and output a voltage relay control signal controlling the relay separately from the control by the microchip.

What is claimed is: 
     
         1 . A method of protecting a battery for an electric vehicle, which comprises a high voltage battery, an inverter for inverting a voltage of the high voltage battery, a relay for selectively blocking a voltage from the high voltage battery to the inverter, and a battery management system for controlling the relay, the method comprising:
 receiving a voltage from the high voltage battery;   comparing the received voltage of the battery with a reference voltage; and   opening the relay when the battery voltage is higher than the reference voltage.   
     
     
         2 . The method of  claim 1 , wherein the comparing of the received voltage of the battery with the reference voltage includes comparing the voltage through an OP AMP comparator disposed inside or outside the battery management system. 
     
     
         3 . The method of  claim 2 , wherein:
 the OP AMP comparator outputs 0 V when the received voltage of the high voltage battery is higher than the reference voltage of the battery management system, and   the OP AMP comparator outputs a predetermined voltage when the received voltage of the high voltage battery is lower than or equal to the reference voltage of the battery management system.   
     
     
         4 . A method of protecting a battery for an electric vehicle, which comprises a high voltage battery, an inverter for inverting a voltage of the high voltage battery, a relay for selectively blocking a voltage from the high voltage battery to the inverter, and a battery management system for controlling the relay, the method comprising:
 receiving a voltage from the high voltage battery;   comparing the received battery voltage with a reference voltage through an operational amplifier (OP AMP) comparator connected with the battery management system, and outputting a voltage relay control signal based on a result of the comparison;   outputting a main relay control signal through a microchip of the battery controller; and   controlling the relay based on at least one of the voltage relay control signal and the main relay control signal.   
     
     
         5 . The method of  claim 4 , wherein the controlling of the relay based on at least one of the voltage relay control signal and the main relay control signal comprises:
 inputting the main relay control signal and the voltage relay control signal to an AND gate of the battery management system as an input signal; and   inputting an output signal of the AND gate to the relay as a control signal.   
     
     
         6 . The method of  claim 5 , wherein:
 the voltage relay control signal is 0 V when the received voltage from the high voltage battery is higher than the reference voltage of the battery management system according to the comparison by the OP AMP comparator, and   the voltage relay control signal is a predetermined voltage when the received voltage from the high voltage battery is equal to or lower than the reference voltage of the battery management system.