A demonstrator of the high-throughput screening process was developed for external use at redoxfox.scai.fraunhofer.de.
The capability of automated potential energy surfaces (PES) exploration algorithms to find products and reactions paths of degradation reactions in organic flow battery electrolytes has been explored. The framework has been applied to degradation reactions of substituted quinones across neutral, basic and acidic conditions. These proof-of-principle applications showed that the proposed framework is able to find the degradation products and reaction mechanisms without their a priori knowledge.
An automatic workflow to optimize the geometry structure of the carbon felt electrode, with consideration of the electrode compression, has been developed. The objective of the optimization algorithm was to maximize the electrolyte utilization rate, in which a homogeneous electrolyte distribution and a high specific surface area was required. The parameter set of the optimization workflow included the fiber diameter, the porosity of the fiber, the fiber direction, the amount of in-plane fiber and the compression ratio.
A flow battery model (RFB-SCL-3D) for performance predictions of a single lab-sized flow battery cell has been developed. The model builds upon and extends the cell performance model for high-throughput screening. However, in contrast to the RfbScFVM model, the RFB-SCL-3D model performs a fully resolved 3D discretization of the electrolyte flow in the porous electrodes and flow field structures. The electrolyte flow is described by the incompressible Navier-Stokes equation in the free-flow regions and the Brinkman equation in the porous electrode structure.
Topology optimization calculations were conducted to enhance the design of a flow battery cell. A homogenized 2D cell model with simple chemistry is developed in COMSOL Multiphysics® and the existing topology optimization framework of the software is used for the calculations.
A spatially resolved 3D microstructure battery model has been developed. For this purpose, a simulation tool developed in-house using the finite volume method. It is set up to simulate a battery half-cell including the membrane as a boundary condition, and consists of coupled, non-overlapping fluid and solid regions. The simulated domain can either be obtained from image reconstruction of the electrode or constructed using CAD software. Both the all-vanadium and TEMPO systems are implemented and successfully validated. In general, the model is capable of providing performance data like half-cell potential or active material concentration distribution within the microstructure and their dependency on the flow regime.
A combined hydraulic/electrochemical/thermal stack model has been developed which incorporate an input interface that allows input parameters to be varied for different chemistries and system designs. System-level modelling considers sizing and energy requirements for pumps.
An optimized techno-economic model was created to enable consideration of further factors influencing the costs and technical properties of organic RFBs. An optimized version of the technoeconomic model was programmed in Python (FLOTE) as a stand-alone software, using the extensive input variables determined in the laboratory itself.
