The invention relates to a method for robust estimation of state of charge (SOC) for a battery cell (6) for an electric vehicle, the method comprising: measuring an output current (/m) from the battery cell; a temperature (Tm) of the battery cell; and an output voltage (y) from the battery cell; providing a SOC estimation model (M) for the battery cell comprising the measured current (/m) and the measured temperature (Tm) to provide an estimated output voltage (y); calculating the estimated output voltage (y) and an intermediate SOC value (SOCint) using the SOC estimation model (M); calculating a voltage difference between the estimated output voltage (y) and the measured voltage (y); estimating the SOC (SOC) for a battery cell by optimizing said SOC estimation model (M) based on the calculated voltage difference and the intermediate SOC value (SOCint). The method is characterized in that the SOC estimation model (M) further comprises a current fault estimate (lf) for an error of the measured current (/m); and/or the SOC estimation model (M) further comprises a voltage fault estimate (yf) for an error of a measured output voltage (ym); and in that the step of estimating the SOC (SOC) for a battery cell is further optimized based on the current fault estimate (lf) and/or the voltage fault estimate {yf). The invention further relates to a computer program comprising program code performing the steps of the method, a computer readable medium carrying such a computer program, a control unit (2) for controlling the monitoring the state of a battery cell, a battery state monitoring system, and an electrical vehicle comprising such a battery state monitoring system.
Battery cell state of charge estimation method and a battery state monitoring system
2022-05-03
Patent
Elektronische Ressource
Englisch
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