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Redox flow batteries: Energy sto...

Redox flow batteries: Energy storage systems for renewables

Higher output for industrial use

Securing sources. That’s good for the environment, but it poses problems for the energy sector. Wind and solar do not generate electricity at a constant rate. Their output depends on the weather. So in the future we will need storage systems to keep the grid in balance. For example, they could store excess electricity produced when it is very windy and then feed it back into the grid when the wind dies down.

Redox flow batteries store electricity as chemical energy in two large tanks. The tanks are filled with salts dissolved in inorganic acids. The tanks are connected with one or more electrochemical cells via which the batteries are charged and discharged. Redox flow batteries currently have an efficiency level of up to 80 percent. The surface area of the cells determines the output of the batteries.

Our know-how lies in the design of the electrochemical cell.

Our aim is to significantly increase the cell area and thus the battery output. Capacity can be changed easily by increasing the size of the tanks. To date, the cell area for practical use has been around 40 square centimeters. We want to achieve a cell size of over 2.50 square meters. That would make it possible to build industrial storage systems with an initial output of 20 megawatts and a capacity of 200 megawatt hours.

Our experts have already succeeded in increasing output by a factor of ten. A further ten-fold increase will be achieved shortly. The final cell size should be reached before the end of 2016.

Successes:

20 megawatts output
200 megawatt hours capacity
Up to 80 percent efficiency