Validation Of A Two Dimensional Model For Vanadium Redox Flow Batteries

Validation of a two-dimensional model for vanadium redox-flow batteries

Redox-Flow batteries can play a crucial role in the future electricity supply in order to balance the time lag between the generation of electrical energy from photovoltaics or wind power and the demand for electrical energy. However, to deploy the technology on a large scale, significant cost reductions are required. A thorough knowledge of the reactions and processes taking place within a redox-flow battery is very helpful for this task and this knowledge can be significantly improved by using a suitable mathematical model to describe the processes in a single cell of a redox-flow battery. Nevertheless, this requires a valid model that has been compared with experimental data and that can reproduce these data plausibly and validly. In this thesis, the validation of a two-dimensional model for the description of potential and current density distributions in the porous electrodes of a vanadium redox-flow battery is presented, taking into account effects of kinetics and mass transport. Newly developed potential probes are used for in-situ measurement of solid and liquid phase potentials within a single cell of a vanadium redox-flow battery. The description of the measured cell voltage and potential probe signals by the model reveals a good congruence between the model and the experimental data, so the model can be regarded as valid. Additional suggestions for improvements of the model and the implementation of further models describing membrane crossover effects or electrolyte properties are given.

Modeling and Control of a Vanadium Redox Flow Battery

This book presents extensive work on the modeling and control aspects of the emerging field of vanadium redox flow batteries. After providing a detailed literature review, it describes a comprehensive model that defines the main phenomena associated with vanadium redox flow batteries, covering electrochemical, thermal, hydraulic, and voltage aspects. Phenomena and models are described in a concise manner using a set of differential equations that share common parameters and states. Various electrochemical models based on conservation principles and operating condition assumptions are described, and used for estimating the state of charge and state of health. Different methodologies for accurately estimating these indicators through offline optimization problems and online observers are presented. In turn, the results obtained from real experimental setups are presented and validated, providing a better understanding of the components, design, and operation of vanadium redox flow batteries.

Multiscale Modeling, Simulation and Design – From Conventional Methods to the Latest in Data Science