Method for removing v2o5 deposits in a redox flow battery module

A method for removing V2O5 deposits in at least one vanadium battery module incorporated in a battery system,

• wherein the battery system comprises;
• at least three battery modules connected in series;
• a power conversion system;
• and
• a control device,
• wherein the at least three battery modules are connected to the power conversion system, and
• wherein each battery module of the at least three battery modules comprises:
• a cell device;
• a tank device for storing an electrolyte;
• and
• two pumps for conveying the electrolyte through the cell device,
• wherein the control device is configured to detect an operating state of the power conversion system and to drive the two pumps in the at least three battery modules,
• wherein the method comprises the following steps in the indicated order:
• identifying at least one battery module having V2O5 deposits from the at least three battery modules;
• switching off pumps of the at least one battery module at a time t1;
• and
• switching on the pumps of the at least one battery module at a time t2,
• wherein a length of a time interval Δt=t2−t1 is selected such that, at time t2, a terminal voltage of the at least one battery module is negative, but overcharging of the electrolyte present in the cell device of the at least one battery module is avoided, and
• wherein switching off the pumps and switching on the pumps are carried out while the battery system is being discharged.