The invention relates to a
monitoring system for the electric quantity of a
lithium battery. The
monitoring system comprises a state monitoring unit, an electric quantity recording unit, an impedance tracking unit, an arithmetic element and the
lithium battery, wherein the state monitoring state monitors the current output
voltage, the output current and the ambient temperature of the
lithium battery; the electric quantity recording unit records the input electric quantity during the charging of the
lithium battery and the output electric quantity during the discharging of the
lithium battery; the impedance tracking unit calculates the internal impedance of the
lithium battery after the charging of the lithium battery is completed every time; the arithmetic element calculates the remaining electric quantity and the remaining working hour of the lithium battery according to input data; the
system monitors the whole charging / discharging process of the lithium battery, takes a complete charging and discharging time as a period, dynamically updates
battery capacity based on an
integral method and eliminates the influence of the variation of the
battery capacity; after the battery is fully charged every time, the impedance tracking unit of the lithium battery is started so as to update the internal
resistor of the lithium battery; finally, the remaining electrical quantity and the remaining working time of the lithium battery are calculated by combining the environment temperature, the loading and the like.