A method for simulating in real time, by means of an overall model, a battery comprising a cell composite made of a plurality of individual cells, a real-time processor being connected to a control device system via a cell voltage emulator, the terminal voltages of the individual cells being calculated on the real-time processor by means of the overall model, the calculated terminal voltages of the individual cells being made available to the control device system by means of the cell voltage emulator, and the overall model comprising a first model, by means of-which a first individual cell is modeled using cell parameters typical for the cell composite, and a second model, comprising the steps: feeding the overall input current of the cell composite to the first model as an input parameter calculating the terminal voltage of the reference cell and at least one further parameter of the reference cell, particularly the charge state, temperature, or internal resistance, by means of the first model, calculating a deviation of the terminal voltage of at least one further individual cell from the terminal voltage of the reference cell by means of the second model, at least one deviation of the further individual cell with respect to the parameter relative to the reference cell being specified to the second model for calculating the deviation of the terminal voltage of the further individual cell relative to the terminal voltage of the reference cell, and the parameter for the further individual cell being determined from the parameter calculated by means of the first model and the specified deviation of the corresponding parameter for the further individual cell relative to the reference cell, in order to reduce the calculation time, so that the parameter is not simulated separately for each individual cell, and the terminal voltage of the further individual cell is calculated from the terminal voltage of the reference cell and the deviation of the terminal voltage of the further individual cell. feeding the overall input current of the cell composite to the first model as an input parameter calculating the terminal voltage of the reference cell and at least one further parameter of the reference cell, particularly the charge state, temperature, or internal resistance, by means of the first model, calculating a deviation of the terminal voltage of at least one further individual cell from the terminal voltage of the reference cell by means of the second model, at least one deviation of the further individual cell with respect to the parameter relative to the reference cell being specified to the second model for calculating the deviation of the terminal voltage of the further individual cell relative to the terminal voltage of the reference cell, and the parameter for the further individual cell being determined from the parameter calculated by means of the first model and the specified deviation of the corresponding parameter for the further individual cell relative to the reference cell, in order to reduce the calculation time, so that the parameter is not simulated separately for each individual cell, and the terminal voltage of the further individual cell is calculated from the terminal voltage of the reference cell and the deviation of the terminal voltage of the further individual cell.