PNNL completes study on revolutionary redox flow battery design for battery energy stationary storage

Jul 2023

The US Department of Energy’s Pacific Northwest National Laboratory (PNNL) recently concluded a year-long study on a new type of flow battery technology. The research was based on the use of an innovative electrolyte solution, which constituted of a simple dissolved sugar, beta-cyclodextrin, in place of commonly vanadium-based electrolytes. Redox flow batteries are garnering significant interest in the BESS market due to their potential to enable cost-effective long-duration energy storage, a region of the market many believe is significantly lacking.

What are redox flow batteries?

While lithium-ion batteries store energy in solid electrolytes, redox flow batteries store energy in liquid electrolytes that are stored in external tanks. During charge and discharge these electrolytes are pumped into a central cell attached to the power module, this is where the electron exchange takes place. The fact that the electrolytes are stored in these separate tanks means they can be scaled indefinitely to store ever-larger amounts of energy. There is a lot of interest in using flow batteries for seasonal storage applications due to their ability to perform ‘deep cycles’ where charge and discharge durations can be several hours. Additionally, they can be used to store energy for extended periods of time by placing the system in ‘offline mode’ where the electrolyte tanks are disconnected in order to prevent flow into the cell stack.

What is the significance of this study?

There are numerous different redox flow battery designs available commercially, the most advanced of which being…


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Image Source: Andrea Starr | PNNL