Our storage concept is a new version of a storage principle that was first introduced 90 years ago. It’s an electrochemical system that uses sodium and sulfur as energy carrier materials and a ceramic solid as electrolyte. In the 1970s and 1980s, battery cells based on this principle with an output of 1 kW and a storage capacity of approx. 6 kWh were developed to production maturity. They are still used in medium-sized storage modules for grid stabilization.
We are going one step further. We plan to carry out the electricity-supplying reaction of sodium and sulfur to sodium sulfides and the electricity-absorbing reverse reaction of sodium sulfides to sodium and sulfur not in small, encapsulated cells, but in large open energy converters, each connected to a tank system for sodium, sulfur, and sodium sulfides. These energy converters could also be described as sodium-sulfur fuel cells or sodium-sulfur redox flow cells. The switch from the principle of the closed battery cell to the fuel cell and the enlargement of the units result in enormous economic advantages. You can find more information about this in our company and technology concept: