Flow battery start-up and recovery management

Abstract

A start-up plating process for a flow cell battery is disclosed. Upon start-up of the flow-cell stack, catalysts may have deplated from the electrodes. The catalyst is replated to the electrode by application of currents to the stack prior to circulating electrolyte fluids.

1 - 2 . (canceled) 
     
     
         3 . A flow cell system, comprising
 a flow cell stack, the flow cell stack including one or more cells, each of the one or more cells including a first half-cell and a second half-cell;   a first circulation pump fluidically coupled between a first electrolyte tank and a first half-cell to circulate the first electrolyte through the first half-cell of the flow stack;   a second circulation pump fluidically coupled between a second electrolyte tank and a second half-cell to circulate a second electrolyte through the second half-cell of the flow stack;   a first mixing valve fluidically coupled to direct the first electrolyte into the second half-cell for mixing of the first electrolyte and the second electrolyte in the second electrolyte tank;   a second mixing valve fluidically coupled to direct the second electrolyte in the first half-cell for mixing of the second electrolyte and the first electrolyte in the first electrolyte tank; and   a start-up controller electrically coupled to provide voltages and currents to the stack, to provide control signals to the first circulation pump and the second circulation pump, and to provide control signals to the first mixing valve and the second mixing valve, wherein the start-up controller performs operations to   force deplete the stack; and   plate the stack.   
     
     
         4 . The system of  claim 3 , further including a first check valve coupled between the first circulation pump and the flow cell stack and a second check valve coupled between the second circulation pump and the flow cell stack. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . The system of  claim 3 , wherein force depleting includes
 activating cross-over valves such that the first electrolyte from a first holding tank is flowed through the second half of the cell and to a second holding tank and the second electrolyte from a second holding tank is flowed through the first half of the cell and to the first holding tank by the circulation pumps.   
     
     
         8 . The system of  claim 3 , wherein plating the stack includes static plating electrodes of the stack by
 applying a current to the stack of the flow cell system to plate a catalyst dissolved in the electrolyte in the stack while the circulating pumps are off; and   turning the circulation pumps on once the static plating is completed.   
     
     
         9 . The system of  claim 8 , wherein plating the stack further includes performing a trickle plating process by applying a current with the circulation pumps ON. 
     
     
         10 . The system of  claim 8 , wherein plating the stack further includes performing a pulse plating process by applying a pulsed voltage with the circulation pumps ON. 
     
     
         11 . The system of  claim 8 , wherein plating the stack further includes performing an initial plating process by initially charging the flow cell. 
     
     
         12 . A method of starting a flow cell system, wherein a first electrolyte is flowed through a first half of a cell and a second electrolyte is flowed through a second half of the cell in a stack of the flow cell system with first and second circulation pumps, comprising
 force depleting the stack by cross-flowing electrolyte through the stack; and   plating the stack.   
     
     
         13 . The method of  claim 12 , wherein force depleting includes
 activating cross-over valves such that the first electrolyte from a first holding tank is flowed through the second half of the cell and to a second holding tank and the second electrolyte from a second holding tank is flowed through the first half of the cell and to the first holding tank by the circulation pumps.   
     
     
         14 . The method of  claim 12 , wherein plating the stack includes static plating electrodes of the stack by
 applying a current to the stack of the flow cell system to plate a catalyst dissolved in the electrolyte in the stack while the circulating pumps are off; and   turning the circulation pumps on once the static plating is completed.   
     
     
         15 . The method of  claim 12 , wherein plating the stack further includes performing a trickle plating process by applying a current with the circulation pumps ON. 
     
     
         16 . The method of  claim 12 , wherein plating the stack further includes performing a pulse plating process by applying a pulsed voltage with the circulation pumps ON. 
     
     
         17 . The method of  claim 12 , wherein plating the stack further includes performing an initial plating process by initially charging the flow cell.