The author's research on energy storage systems generally was confronted with five characteristics, i.e., complex, interacting, transporting, reacting, and heterogeneous systems. Hence, we refer to these kind of systems as Complex Heterogeneous Systems (CHeSs).

The work considers interacting systems that exchange energy, mass, information, etc. in various ways. The elementary building blocks of CHeSs are based on fundamental thermodynamic, chemical, material, physical, and mathematical principles such as variational and graph-theoretic concepts. It investigates ways of defining complexity, computing percolation thresholds, making smart decisions also by learning from data/past experiences (e.g., providing a systematic approach towards battery management systems), and identifying battery life (e.g., by blow-up analysis of highly nonlinear concentrated solutions).

Ultimately, the elaborated tools shall allow the reader to obtain a general understanding for simulating (also on quantum computers), controlling, and developing CHeSs as well as to pave the way for a general theory on CHeSs generalizing the view on complexity, measurement, estimation, and control.