NOVELTY - The dynamic behavior is described in operation by an electric reference model (M) comprised of a capacitor (C) and the associated resistor (R1). Deviation of the sum of over-voltages and the initial voltage with respect to the currently measured voltage is determined and integrated. The parameter data set version with the smallest square error is assigned. The parameter record variant is defined as a new reference dataset for the description of battery model and for the predictive determination of the maximum power of the energy storage.    USE - Method for determining model parameters of electrochemical energy storage such as lithium-ion battery in battery management system (claimed) of electric and hybrid vehicles.    ADVANTAGE - A simple and effective method for determining the current parameters for providing the dynamic behavior of the energy store model and for adapting the parameters of the model during operation of the energy storage is provided. Excellent predictive determination of the maximum power available with respect to the energy storage for a predefined period from the current operating point is enabled. The adaptation of parameters is carried out during the operation of energy storage. Complex calculations consisting of matrix operations are not necessary.    DETAILED DESCRIPTION - The dynamic behavior is described in operation by an electric reference model. The reference model is comprised of a capacitor and the associated resistors. The parameter values are added to form a parameter data set and are adapted to the current state during the operation of energy storage. Starting from a reference parameter data set, several parameter data record variants are formed for each of the iteration based on the measured current and over-voltage (Umodell-t) of the energy storage. Deviation of the sum of over-voltages and the initial voltage with respect to the currently measured voltage is determined and integrated. The parameter data set version with the smallest square error is assigned. The parameter record variant is defined as a new reference dataset for the description of battery model and for the predictive determination of the maximum power of energy storage. An INDEPENDENT CLAIM is included for a battery management system.    DESCRIPTION OF DRAWING(S) - The drawings show a graphical representation of the power dependence of battery resistance of a brand new lithium-ion battery and an aged lithium-ion battery, and the schematic circuit diagrams for simulating the dynamic characteristics of the battery and the model of the battery impedance. (Drawing includes non-English language text)    Capacitor (C)    Capacitor current (Ic-t)    Electric reference model (M)    Resistor (R1)    Over-voltage (Umodell-t)