What are the types of flow battery components

Flow batteries typically include three major components: the cell stack (CS), electrolyte storage (ES) and auxiliary parts. A flow battery's cell stack (CS) consists of electrodes and a membrane. It is where electrochemical reactions occur between two electrolytes, converting chemical energy into electrical energy.

Flow batteries are a type of electrochemical ES, which consists of two chemical components dissolved in liquid separated by a membrane. Charging and discharging of batteries occur by ion transferring from one component to another component through the membrane. The biggest advantages of flow batteries are the capability of pack in large volumes.

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.

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.

Over the past 20 years, four designs of flow batteries have been demonstrated: vanadium redox (VRB), zinc bromine (ZnBr), polysulphide bromide (PSB) and cerium zinc (CeZn). Major installations, in Japan and North American, use the vanadium redox and zinc bromine designs. Energy efficiency is about 85% for VRB system and 75% for ZnBr system.

Compared to lithium-ion batteries, flow batteries offer superior scalability due to their ability to easily increase energy capacity by adding more electrolytes to the tanks. Lithium-ion batteries, on the other hand, have limited scalability, as their capacity is primarily determined by the number of cells in the battery pack.