We develop models - from battery cells to complete battery systems. In addition to simulating highly dynamic processes, we also can model steady state conditions depending on the degree of precision and computing speed required. Our library contains electric, electrochemical, thermal and electro-thermal models. We developed models for lead, redox flow, high temperature and various Li-ion batteries. Fraunhofer ISE offers aging models for the different technologies in which the lifetime for the particular application as well as lifetime cost analyses can be determined by simulation. The models are being continuously further developed and subsequently parameterized and validated with measurements from our battery lab. They have been successfully implemented in projects, e.g. the simulation-based development of optimized charging and operating strategies for battery storages. Additionally, the models serve as a basis in various projects for the precise identification of the charging and aging states as well as lifetime predictions for the specific application.