Method for providing a cell impedance model for a battery cell

Abstract

The invention relates to a computer-implemented method for providing a cell impedance model for a battery cell of a device battery, comprising the following steps:- Providing the cell impedance model with a low-frequency component ofRD(s)(s+ωhs+ωl)η(I,SOC) as an Oustaloup approximation of a substantially linear low-frequency part of the Nyquist relationship, wherein the exponent value η represents the gradient of an imaginary part of the cell impedance over a real part of the cell impedance, wherein ωh, ωl are predetermined upper and lower values, respectively.lower frequency of the low-frequency range of the Nyquist relationship, where I corresponds to a cell current and SOC to a state of charge of the battery cell and RD(s) corresponds to an impedance parameter and where s is the Laplace variable;- measuring (S1) the battery cell at different operating points and at different frequencies in order to obtain series of measurements with a terminal voltage, wherein the operating points are determined at least by the cell current and / or the state of charge;- parameterizing (S2) and providing (S3) the cell impedance model with the series of measurements by minimizing a difference between the measured and modeled terminal voltage, wherein the exponent value η is parameterized using an exponent function depending on the respective operating point.

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