Flow Battery System and Method of SOC Determination

A flow battery system comprising:

• a flow cell including a negative electrode, a separator, and a positive electrode;
• a reservoir operably connected to the positive electrode and including an aqueous electrolyte;
• a first sensor configured to generate a current signal indicative of an amplitude of a current passing into or out of the flow cell;
• a second sensor configured to generate a voltage signal indicative of an output voltage across the flow cell;
• a memory in which command instructions are stored;
• a model of the flow cell stored within the memory;
• and
• a processor configured to execute the command instructions to
• obtain the current signal and the voltage signal,
• estimate a state of charge (SOC) of the flow cell using the obtained current signal,
• compute a model voltage of the flow cell using the obtained current signal, the obtained voltage signal, and the model,
• compare the model voltage with the obtained voltage signal,
• calculate a voltage error based upon the comparison of the model voltage with the obtained voltage signal, and
• correct the estimated SOC based upon the voltage error.