What is the flow in a flow battery

In contrast with conventional batteries, flow batteries store energy in the electrolyte solutions. Therefore, the power and energy ratings are independent, the storage capacity being determined by the quantity of electrolyte used and the power rating determined by the active area of the cell stack.

A flow battery stores energy in two soluble redox couples, which are comprised of exterior liquid electrolyte containers. During charging, one electrolyte is oxidized at the anode, while during discharging, another electrolyte is reduced at the cathode. In this way, the electrical energy is transferred to the electrolyte.

Scalability: One of the standout features of flow batteries is their inherent scalability. The energy storage capacity of a flow battery can be easily increased by adding larger tanks to store more electrolyte.

Flow batteries have a storied history that dates back to the 1970s when researchers began experimenting with liquid-based energy storage solutions. The development of the Vanadium Redox Flow Battery (VRFB) by Australian scientists marked a significant milestone, laying the foundation for much of the current technology in use today.

Electrolytes: The two most important elements of a flow battery are the positive and negative electrolytes, typically stored in separate external tanks. These electrolytes are usually in liquid form and contain ions that facilitate the battery's energy conversion process.

Electricity is generated or stored when ions move between these liquids through the membrane, with the flow of electricity happening in an external circuit. The amount of energy a flow battery can store depends on how much liquid there is, while the size of the electrodes determines the power it can generate.