Method for evaluating an electric connection of an electric energy storage device to an onboard electrical system, electronic battery evaluating system and vehicle

1 . A method for evaluating an electric connection of an electric energy storage device to an onboard electrical system of an at least partially electrically operated vehicle, wherein the onboard electrical system is supplied with electric energy by the electric energy storage device, and with a voltage converter of the onboard electrical system, which is connected to the electric energy storage device, at least one component of the onboard electrical system is supplied with an output voltage of the voltage converter, the method comprising:

changing a specified voltage of the voltage converter, by which the output voltage can be specified, in a specified time interval, whereby a battery voltage and a battery current of the electric energy storage device can be influenced;

detecting the battery voltage of the electric energy storage device within the time interval;

detecting the battery current of the electric energy storage device within the time interval;

comparing a time curve of the battery voltage and a time curve of the battery current; and

evaluating the electric connection of the electric energy storage device to the onboard electrical system depending on the compared time curves of the battery voltage and of the battery current; wherein

comparing the time curves of the battery voltage and of the battery current comprises determining if these two time curves are in phase.

2 . The method of claim 1 , wherein the specified voltage is changed in the time interval such that a voltage value of the specified voltage is increased or decreased by a specified voltage value.

3 . The method of claim 1 , wherein by changing the specified voltage, a determination of an internal resistance of the electric energy storage device is excited.

4 . The method of claim 3 , wherein the determination of the internal resistance is performed depending on an average voltage of the time curve of the battery voltage and an average current of the time curve of the battery current.

5 . The method of claim 1 , wherein the change of the specified voltage is effected depending on a specified switching frequency.

6 . The method of claim 1 , wherein for comparing the time curves of the battery voltage and of the battery current, the time curves are filtered with a digital filter depending on the changed specified voltage.

7 . The method of claim 1 , wherein immediately after changing the specified voltage, a step response is respectively ascertained as the time curve of the battery voltage and of the battery current.

8 . An electronic battery evaluating system with a processor and at least one detector, wherein the electronic battery evaluating system is configured for:

changing a specified voltage of a voltage converter, by which an output voltage can be specified, in a specified time interval, whereby a battery voltage and a battery current of an electric energy storage device can be influenced;

detecting the battery voltage of the electric energy storage device within the time interval;

detecting the battery current of the electric energy storage device within the time interval;

comparing a time curve of the battery voltage and a time curve of the battery current; and

evaluating an electric connection of the electric energy storage device to an onboard electrical system depending on the compared time curves of the battery voltage and of the battery current, wherein

comparing the time curves of the battery voltage and of the battery current comprises determining if these two time curves are in phase.

9 . A vehicle with an electronic battery evaluating system of claim 8 .

10 . The vehicle of claim 9 , wherein the specified voltage is changed in the time interval such that a voltage value of the specified voltage is increased or decreased by a specified voltage value.

11 . The vehicle of claim 9 , wherein by changing the specified voltage, a determination of an internal resistance of the electric energy storage device is excited.

12 . The electronic battery evaluating system of claim 8 , wherein the specified voltage is changed in the time interval such that a voltage value of the specified voltage is increased or decreased by a specified voltage value.

13 . The electronic battery evaluating system of claim 8 , wherein by changing the specified voltage, a determination of an internal resistance of the electric energy storage device is excited.

14 . The electronic battery evaluating system of claim 13 , wherein the determination of the internal resistance is performed depending on an average voltage of the time curve of the battery voltage and an average current of the time curve of the battery current.

15 . The electronic battery evaluating system of claim 8 , wherein the change of the specified voltage is effected depending on a specified switching frequency.

16 . The electronic battery evaluating system of claim 8 , wherein for comparing the time curves of the battery voltage and of the battery current, the time curves are filtered with a digital filter depending on the changed specified voltage.

17 . The electronic battery evaluating system of claim 8 , wherein immediately after changing the specified voltage, a step response is respectively ascertained as the time curve of the battery voltage and of the battery current.