Method for operating a battery sensor, and battery sensor

Abstract

The invention relates to a method for operating a battery sensor and to a battery sensor, comprising at least one first battery sensor connection (Vat+) and a second battery sensor connection (Vba-),in particular for connecting to a battery and a load current connection, a current measuring device for detecting the load current (Iload), comprising a first measuring resistor element (R1) and a second measuring resistor element (R2), wherein the first and the second measuring resistor element (R1, R2) are connected in series between the load current connection and the second battery sensor connection (Vbat-), and a reference current circuit with at least one reference resistor (Rref, Rref1, Rref2), said reference resistor (Rref, Rref1, Rref2) being in contact with the first battery sensor connection (Vbat+) and a contact point provided between the measuring resistor elements (R1, R2). The electric resistance of the first resistor element (R1) is determined by connecting the reference current (Iref) and detecting the voltage drops (U1, U2) over the first and second measuring resistor element (R1, R2) and the battery voltage (Vbat), determining the reference current (Iref) from the quotient of the battery voltage (Vbat) and the electric resistance of the reference resistor element (Rref), and determining the electric resistance of the first resistor element (R1) from the detectedvoltage drops (U1, U2), the reference current (Iref), and at least one correction factor (alpha, beta) which characterizes the relationship between the electric resistance of the first resistor element (R1) and the electric resistance of the second resistor element (R2).

Description

technical field [0001] The invention relates to a method for operating a battery sensor and to a battery sensor. Background technique [0002] Such battery sensors include, in particular, devices for measuring the battery voltage, the battery current drawn or delivered by the battery, and the ambient temperature of the battery. Battery sensors also typically include a microcontroller that buffers and filters these measurements and calculates other battery parameters, such as state of charge or battery internal resistance, from these measurements. [0003] In the case of designs according to the prior art, the load current is measured using high-precision resistors or sensors for measuring the magnetic field strength. A disadvantage of previous designs is particularly the high cost, especially of the resistive material used to manufacture the resistive material with an approximately constant resistance value over the typical temperature range of -40°C to 105°C. An example o...

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Problems solved by technology

[0007] However, it has been found that continuous recalibration is difficult even during the simultaneous measurement of the strongly time-varying high currents that occur in motor vehicles under prevailing boundary conditions, especially with the expected low current consumption of the sensors, which is because the reference current to be applied for calibration is small and can only be applied for a short time

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