Flow Batteries with Modular Arrangements of Cells

A method of charging a recirculating redox flow battery, the method comprising:

• pumping liquid electrolytes into a reaction stack assembly for a first cycle, the reaction stack assembly comprising a plurality of cell modules connected to one another with electrical connections remotely switchable between a parallel connection and a series connection, the plurality of cell modules being fluidically connected in parallel with a source of the liquid electrolytes;
• remotely switching the electrical connections between a first at least two of the plurality of cell modules from a series connection to parallel connection;
• and
• pumping the liquid electrolytes into a stack assembly for a second cycle.

A redox flow battery system comprising:

• a plurality of cascade stages, each of the plurality of cascade stages comprising a plurality of cells arranged into at least one bipolar cell module, the plurality of cascade stages being electrically connected in series with one another;
• and
• a source of redox electrolyte coupled to the plurality of cascade stages,
• wherein:
• the plurality of cascade stages are coupled in fluidic series so as to direct the redox electrolyte through all of the plurality of cascade stages from a first cascade stage of the plurality of cascade stages positioned at a high state-of-charge end of the plurality of cascade stages to a last cascade stage of the plurality of cascade stages positioned at a low state-of-charge end of the plurality of cascade stages;
• and
• a respective mean state-of-charge of the redox electrolyte in each cascade stage of the plurality of cascade stages decreases according to a non-linear monotonic progression from a first mean state-of-charge of the redox electrolyte in the first cascade stage to a last mean state-of-charge of the redox electrolyte in the last cascade stage.