Redox Flow Battery for Energy Storage

To realize a low-carbon society, the introduction of renewable energies, such as solar or wind power, is increasingly being promoted these days worldwide. A major challenge presented by solar and wind power generators is their fluctuation in output. If they are introduced in large numbers to the power system, problems, such as voltage rises, frequency fluctuations and surplus of the generated power, are predicted to occur. As a solution to these problems, energy storage technologies are attracting attention, amongst which energy storage batteries are expected to become indispensable for use. Various energy storage batteries are being developed and many application verification projects using such batteries are currently being promoted. Thus, expectations are growing for their practical use to the power system in near future. The redox flow (RF) battery, a type of energy storage battery, has been enthusiastically developed in Japan and in other countries since its principle was publicized in the 1970s(1). Some such developments have been put into practical use. This paper reviews the history of the RF battery’s development, along with the status quo of its use.