The term "ion mobility" suggests that ions are moving through the host material. However, the question arises whether really ions move as there is no unique way to associate charge to a particular atom in an extended material. Consequently, partial charges are typically associated with the single atoms. While the concept of partial charges is frequently used in chemistry to gain an understanding of processes and reactions, an accurate quantum mechanical description, in the sense of a single observable, of atoms in molecules, is not possible. As a consequence, atomic partial charges have been described as "unicorns" before, while Cho et al. recently suggested the term "proxy variable" to be more appropriate. Regardless of the correct terminology, "atoms in molecules" (AIM) as a concept remains a somewhat arbitrarily human-defined tool. Nevertheless, many well-established mechanisms, like nucleophilic and electrophilic attacks in reactions, atomic electronegativities, or oxidation states in metalloorganic compounds, rely on this idea of an existing charge partition. There is, therefore, a substantial demand for charge partition schemes to allow QM calculations to establish a proper connection to these concepts. All such methods must divide and allocate the existing charges to their respective atoms. This division can be done in two ways: by a sharp separation of real space where every atom is allocating a specific volume or by a softer partitioning where atomic volumes can overlap. It is essential to highlight that neither of the two approaches is necessarily better than the other, and their usefulness relies heavily on the desired purpose. Many reviews, in particular within the molecular chemistry community, have addressed and discussed the variety of charge partitioning schemes available today. While a comprehensive overview of the many different methods is far beyond the scope of this paper, we nonetheless wish to introduce some of the most common schemes with a focus on their implementations within the field of ion mobility in crystalline battery materials.