The lithium-ion (li-ion) battery is still the most widely-used and available technology for energy storage, which Germany requires in substantial volumes for Energy Turnaround. For this reason, the Karlsruhe Institute of Technology (KIT) is spearheading a project called “BiFlow” to develop a novel hybrid storage system which combines the advantages of a li-ion battery with a redox flow battery.
“Power and energy in redox flow batteries can be scaled as required. In addition, they have a long service life and cycle stability as well as a particularly high operational reliability,” explains Nina Munzke, BiFlow’s project manager at KIT’s battery centre in a . By combining the two battery types, she says, “we can combine the specific advantages and compensate for the disadvantages.”
In the BiFlow pilot, the student halls of residence “STAGE76” in Bruchsal will be fitted with a state-of-the-art hybrid system to supply the occupants with heat and electricity and to provide three charging points for electric vehicles. Munzke goes on: “We want to use the electrolyte tanks of the redox flow battery for heat storage and thus increase the overall efficiency of the plant. This form of combined heat and power generation is a world premiere.”
Project partner Storion Energy will install the electrolyte tanks and have created a special stack for the task which can provide high power densities for heat accumulation. The Fraunhofer Institute for Chemical Technology (ICT) is developing a special electrolyte formulation for the battery which is suitable for thermal use. The battery system will have a service life of 20 years and at the end of it, the electrolyte can even be reused. KIT is responsible for overall integration and intelligent control of the system.
The Federal Ministry for Economic Affairs and Energy is funding the project with more than EUR 1.3 million.