In this presentation, the results of the ZSIM project, funded by the German Federal Ministry of Education and Research (BMBF) will be presented. The aim of the project, carried out jointly by Fraunhofer IEE and MicroNova AG, was to raise the electrical simulation of battery cells to a new technological level for the development of algorithms for battery management systems. Future generations of battery management systems (BMS) will use advanced measurement methods such as electrochemical impedance spectroscopy (EIS). In order to successfully test such BMS, it is necessary to simulate the electrochemical behavior in the AC range with high dynamics and accuracy. With the successful completion of the ZSIM project, it is now possible to create a simulation for a battery cell in a very short time, which shows the behavior of a battery cell e.g. for a temperature of -20°C, a degree of aging of 30% and a state of charge of 70%. Bringing a real battery cell into such a state for a test involves considerable effort. It is almost impossible to repeat such a test.