Case study No. 19:
Redox-Flow Battery

Initial situation

When used as a redox-flow battery, vanadium is dissolved in sulfuric acid and has four different oxidation levels. The positive and negative electrolytes are stored in two tanks and pumped to the galvanic cell, which is divided by a membrane, for charging and discharging as needed.. In this cell, the actual chemical redox reaction takes place, in which one part of the vanadium is reduced and the other is oxidized.

In addition to a current flow and a voltage of approx. 1.4 V at 30°C, heat losses are generated, which are fed into the system.


The Vanadium Redox Flow electrolyte is a very oxidation-friendly temperature-sensitive system. Both the longevity of the electrolyte and the best working point must be guaranteed. Metallic foreign ions must also be avoided for the purity of the system.


Plastic heat exchangers in all variants can be used for cooling the electrolyte.
– as an immersion type heat exchanger in the energy storage tanks to maintain the required temperature.
– as a liquid/liquid heat exchanger (tube plate heat exchanger or shell and tube heat exchanger) in the pipelines from the tanks to the cells.
– as liquid/air (gas-water exchanger), which is installed in the housing a complete system.

Individual solutions depend on customer preferences, environmental conditions and legal requirements


Redox-Flow batteries can be used worldwide and in severe external conditions if they can be tempered with the help of a Calorplast heat exchanger. Due to the plastic, there are no foreign ions in the electrolyte and the heat exchange can also take place corrosion-free and low-maintenance.