Battery storage systems are technologies that can store electrical energy and release it again when needed. These systems consist of battery cells that are monitored and controlled by a battery management system (BMS). Modern battery storage systems often use lithium-ion technology, which is characterized by high energy density and durability. The stored electricity can come from various sources, in particular from renewable energy sources such as photovoltaic systems. Applications such as peak shaving, grid stabilization and the combination with photovoltaic systems to maximize self-consumption are particularly interesting.