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AssigneeHella GmbH & Co. KGaA
InventorsRudolf Deinzer, Tomasz Efner, Andreas Ernst
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A method and an apparatus for monitoring a low-pass filter, preferably a capacitor in a low-pass filter, a battery management system and a battery are provided. The apparatus includes a switch connected in series with a resistor, and a capacitor connected in parallel with the resistor. When the switch carries out a switching operation, the voltage changes within a very short time from a first to a second voltage value. A voltage detection device measures the voltage during switching and at at least one further point in time, 0.5 to 5 milliseconds later. Determining the speed at which the voltage changes from the first voltage value to the second voltage value makes it possible to determine whether the capacitor is functional and/or makes it possible to determine the resistance. Determining the internal resistance of a battery cell also makes it possible to determine the state of charge of a battery.
A method for monitoring a low-pass filter, the low-pass filter comprising at least one resistor and at least one capacitor, the capacitor being connected in parallel with the resistor, a voltage is determined with respect to one side of the capacitor, and the voltage at the capacitor is switchable by at least one switch between a first setpoint voltage value and a second setpoint voltage value, the method comprising:
Dependencies are inferred from the claim text.