Flow battery start-up and recovery management
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. A method of performing a start-up of a flow cell system, wherein electrolyte is flowed through cells in a stack of the flow cell system with circulation pumps, comprising:
performing a static plating by applying a current to a stack of the flow cell system with the circulation pumps turned off to plate a catalyst dissolved in the electrolyte onto electrodes of the cells in the stack;
turning circulation pumps on once the static plating step is completed to flow electrolyte through the stack of the flow cell system.
2. The method of claim 1 , further including
performing a trickle plating process by applying a current with the circulation pumps ON;
performing a pulse plating process by applying a pulsed voltage with the circulation pumps ON; and
performing an initial plating process by initially charging the flow cell.
3. A flow cell system, comprising a flow cell stack;
a first circulation pump fluidically coupled between a first electrolyte tank and the flow cell stack to circulate the a electrolyte through the flow stack;
a second circulation pump fluidically coupled between a second electrolyte tank and the flow cell stack to circulate a second electrolyte through the flow stack;
a first mixing valve fluidically coupled between the first circulation pump and the second circulation pump to allow for mixing of the first electrolyte and the second electrolyte in the second electrolyte tank;
a second mixing valve fluidically coupled between the second circulation pump and the first circulation pump to allow for mixing of the second electrolyte and the first electrolyte in the first electrolyte tank; and
a start-up controller configured to:
provide voltages and currents to the stack;
provide control signals to the first circulation pump and the second circulation pump;
provide control signals to the first mixing valve and the second mixing valve, wherein the start-up controller, upon start-up of the flow cell system,
cause the system to perform a static plating by applying a current to the flow-cell stack of the flow cell system with the first circulation pump and the second circulation pump turned off to plate a catalyst dissolved in the electrolyte onto electrodes of cells in the flow-cell stack; and
turn the first circulation pump and the second circulation pump on once the static plating step is completed to flow electrolyte through the flow-cell stack of the flow cell system.
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. The system of claim 3 , wherein the start-up controller is further configured to:
provide a small current to the flow cell stack with the first circulation pump and the second circulation pump OFF;
provide a current with the circulation pumps ON;
apply a pulsed voltage with the circulation pumps ON; and
perform an initial plating process by initially charging the flow cell.