Abstract: A method of operating a redox flow battery string including at least first and second redox flow batteries and an outside power source includes: providing a least first and second redox flow batteries in a string electrically connected in a string, and each redox flow battery having a state-or-charge (SOC) and an electrical load, wherein the electrical load for at least one of the first and second redox flow batteries in the string is powered by the outside power source; obtaining an SOC value for each redox flow battery in the string; identifying a target SOC value in the string; and adjusting the SOC value for at least one of the first and second redox flow batteries to correspond to the target SOC value by using a portion of stored energy in the at least one first or second redox flow battery to supply power to the electrical load.

Abstract: A method of operating a redox flow battery string including at least first and second redox flow batteries and an outside power source includes: providing a least first and second redox flow batteries in a string electrically connected in a string, and each redox flow battery having a state-or-charge (SOC) and an electrical load, wherein the electrical load for at least one of the first and second redox flow batteries in the string is powered by the outside power source; obtaining an SOC value for each redox flow battery in the string; identifying a target SOC value in the string; and adjusting the SOC value for at least one of the first and second redox flow batteries to correspond to the target SOC value by using a portion of stored energy in the at least one first or second redox flow battery to supply power to the electrical load.

Abstract: A method of operating a redox flow battery includes: providing a redox flow battery configurable to be in off and on states and to be in an islanded state , the redox flow battery including an electrochemical cell in fluid communication with anolyte and catholyte storage tanks, wherein a portion of the anolyte and a portion of the catholyte is contained in the electrochemical cell, and wherein the redox flow battery is at least partially charged; identifying the redox flow battery to be in an off and islanded state; maintaining stored energy in the electrolyte in the electrochemical cell when the redox flow battery is in the off and islanded state; and using the energy stored in the electrolyte in the electrochemical cell to start the redox flow battery and enter the on state.

Abstract: A method of operating a redox flow battery includes providing a redox flow battery including an anolyte storage tank configured for containing a quantity of anolyte and an anolyte headspace, a catholyte storage tank configured for containing a quantity of a catholyte and a catholyte headspace, and a gas management system comprising at least one open conduit interconnecting the anolyte headspace and the catholyte headspace for free gas exchange between the anolyte and catholyte headspaces, and a passive gas exchange device in gaseous fluid communication with the anolyte headspace, the passive gas exchange device configured to release gas from the anolyte headspace to an exterior battery environment when an interior battery pressure exceeds an exterior battery pressure by a predetermined amount, and operating the battery.

Abstract: A method of operating a redox flow battery includes providing a redox flow battery including an anolyte storage tank configured for containing a quantity of anolyte and an anolyte headspace, a catholyte storage tank configured for containing a quantity of a catholyte and a catholyte headspace, and a gas management system comprising at least one open conduit interconnecting the anolyte headspace and the catholyte headspace for free gas exchange between the anolyte and catholyte headspaces, and a passive gas exchange device in gaseous fluid communication with the anolyte headspace, the passive gas exchange device configured to release gas from the anolyte headspace to an exterior battery environment when an interior battery pressure exceeds an exterior battery pressure by a predetermined amount, and operating the battery.

Abstract: Methods of determining concentrations and/or amounts of redox-active elements at each valence state in an electrolyte solution of a redox flow battery are provided. Once determined, the concentrations and/or amounts of the redox-active elements at each valence state can be used to determine side-reactions, make chemical adjustments, periodically monitor battery capacity, adjust performance, or to otherwise determine a baseline concentration of the redox-active ions for any purpose.

Abstract: A redox flow battery includes an anolyte storage tank configured for containing a quantity of anolyte and an anolyte headspace; a catholyte storage tank configured for containing a quantity of a catholyte and a catholyte headspace; and a gas management system comprising at least one conduit interconnecting the anolyte headspace and the catholyte headspace, and a gas exchange device configured to contain or release an evolving gas from either or both of the anolyte and catholyte storage tanks to an exterior battery environment when an interior battery pressure exceeds an exterior battery pressure by a predetermined amount.

Abstract: A method of operating a redox flow battery string includes providing a plurality of redox flow batteries, each redox flow battery in electrical communication with at least one other redox flow battery, and each redox flow battery comprising an anolyte storage tank including a quantity of anolyte, a catholyte storage tank including a quantity of catholyte, and an electrochemical cell in fluid communication with the anolyte and catholyte storage tanks; obtaining an open circuit voltage value for each redox flow battery in the string; identifying a predetermined open circuit voltage value in the string; and adjusting the open circuit voltage value for each redox flow battery to correspond to the predetermined open circuit voltage value. A redox flow battery string system includes a plurality of redox flow batteries each redox flow battery in electrical communication with at least one other redox flow battery having an open circuit voltage value.

Abstract: A method of operating an all vanadium redox flow battery includes providing an all vanadium redox flow battery comprising an anolyte storage tank including a volume of anolyte and a catholyte storage tank including a volume of catholyte; an electrochemical cell in fluid communication with the anolyte and catholyte storage tanks; and a predetermined range for the ratio of vanadium concentration between the anolyte and the catholyte; and transferring an amount of catholyte from the catholyte storage tank to the anolyte storage tank, or an amount of anolyte from the anolyte storage tank to the catholyte storage tank, to restore the ratio of vanadium concentration to the predetermined range. An all vanadium redox flow battery system includes means for transferring anolyte and catholyte between the anolyte and catholyte storage tanks to maintain a predetermined range for the ratio of vanadium concentration between the anolyte and the catholyte.

Abstract: A redox flow battery includes an anolyte storage tank configured for containing a quantity of anolyte and an anolyte headspace; a catholyte storage tank configured for containing a quantity of a catholyte and a catholyte headspace; and a gas management system comprising at least one conduit interconnecting the anolyte headspace and the catholyte headspace, and a gas exchange device configured to contain or release an evolving gas from either or both of the anolyte and catholyte storage tanks to an exterior battery environment when an interior battery pressure exceeds an exterior battery pressure by a predetermined amount.

Abstract: Methods of determining concentrations and/or amounts of redox-active elements at each valence state in an electrolyte solution of a redox flow battery are provided. Once determined, the concentrations and/or amounts of the redox-active elements at each valence state can be used to determine side-reactions, make chemical adjustments, periodically monitor battery capacity, adjust performance, or to otherwise determine a baseline concentration of the redox-active ions for any purpose.

Abstract: Disclosed herein are improved electrochemical cell stacks having at least one protective channel on an end of the stack. Redox flow batteries (RFBs) containing the “protected” electrochemical cell stacks, and methods of operating such RFBs, are also provided.

Abstract: A barrier on the surface of the negative electrolyte solution of a redox flow battery can decrease air oxidation of a charged species in the negative electrolyte solution and can decrease water loss from the negative electrolyte solution. A negative electrolyte tank including a barrier on the surface of the negative electrolyte can have many advantages, including simplified setup, low cost, and low maintenance.

Abstract: Disclosed herein are improved electrochemical cell stacks having at least one protective channel on an end of the stack. Redox flow batteries (RFBs) containing the “protected” electrochemical cell stacks, and methods of operating such RFBs, are also provided.