Li-Ion batteries have for long been recognized as an efficient way to store electric energy. For use in electro mobility applications, however, these batteries have to meet several design criteria, such as number of charge/discharge cycles, energy density and safety.The scope of SPP 1473 “WeNDeLIB” is the systematic investigation of materials interaction between the various materials used for cathode, anode, electrolyte and separators. The constitution of the relevant systems has been recognized as an important issue to understand the performance of the whole assembly. While experimental work cannot be dispensed with, it is clear that due to the high amount of components present in these systems, their thermodynamic modeling is desirable. CALPHAD, however, is a semi empirical method that requires thermodynamic data and phase equilibrium information as an input.