A flow battery is a fully rechargeable electrical energy storage device where fluids containing the active materials are pumped through a cell, promoting reduction/oxidation on both sides of an ion-exchange membrane, resulting in an electrical potential.
A typical flow battery has been shown in Fig. 8. Some of the main characteristics of flow batteries are high power, long duration, and power rating and the energy rating are decoupled; electrolytes can be replaced easily . Fig. 8. Illustration of flow battery system [133,137]. 2013, Renewable and Sustainable Energy Reviews Zhibin Zhou, ...
Flow batteries comprise two components: Electrochemical cell Conversion between chemical and electrical energy External electrolyte storage tanks Energy storage Source: EPRI K. Webb ESE 471 5 Flow Battery Electrochemical Cell Electrochemical cell Two half-cellsseparated by a proton-exchange membrane(PEM)
How does a flow battery differ from a conventional 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.
Are flow batteries scalable?
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.
How long does a flow battery last?
Flow batteries can release energy continuously at a high rate of discharge for up to 10 h. Three different electrolytes form the basis of existing designs of flow batteries currently in demonstration or in large-scale project development.
What is the difference between power and capacity of a flow battery?
The capacity is a function of the amount of electrolyte and concentration of the active ions, whereas the power is primarily a function of electrode area within the cell. Similar to lithium-ion cells, flow battery cells can be stacked in series to meet voltage requirements. However, the electrolyte tanks remain external to the system.