The invention provides an all-
vanadium redox flow battery state-of-charge online monitoring method and
system. The monitoring method comprises the steps that the
vanadium ion concentration value of each valence state in positive and negative
electrode electrolyte in the battery charging and discharging process is acquired and open-circuit
voltage is recorded; the state-of-charge of the positive and negative
electrode electrolyte is calculated via the
vanadium ion concentration value; a relation equation of open-circuit
voltage and the corresponding state-of-charge is obtained according to the
relational graph of the state-of-charge and open-circuit
voltage through fitting; and the state-of-charge of the positive and negative
electrode electrolyte of a battery to be measured is obtained according to the relation equation and current open-circuit voltage. The relevant parameters of the positive and negative electrode electrolyte are acquired so that unnecessary error in the calculation process of the battery state-of-charge can be weakened and finally the state-of-charge of the
battery electrolyte can be obtained through measurement. According to the method, an existing open-circuit voltage method equation is corrected, and fitting of a negative electrode relation equation and a positive electrode relation equation is respectively performed so that the accurate state-of-charge of the positive and negative electrode electrolyte can be calculated.