Monitoring system for monitoring electric quantity of battery

The utility model relates to a monitoring system for monitoring the electric quantity of a battery. The monitoring system includes a current monitoring circuit. The current monitoring circuit includes a parallel resistor composed of resistors R28 and R31 connected in parallel. The parallel resistor is connected to the cathode of the battery. Two ends of the parallel resistor are connected respectively with a current output end and a current input end. The anode of the batter is grounded. The current output end is grounded via a capacitor C22. The monitoring system further comprises an operational amplifier U2; a positive input end and a negative input end of the operational amplifier U2 are connected to the current output end and the current input end respectively via resistors R11 and R13; the negative input end is connected to an output end via a resistor R15; a positive power supply end of the operational amplifier U2 is connected to a power supply end via a resistor R8; and a negative power supply end of