Method and apparatus for determining an operating point-dependent change in resistance factor and vehicle

• US 9,784,796 B2
• Filed: 10/14/2015
• Issued: 10/10/2017
• Est. Priority Date: 10/15/2014
• Status: Active Grant

• Current Assignee: Volkswagen AG
• Original Assignee: Volkswagen AG
• Inventors: Schleicher, Jorg, Drenkelforth, Sascha, Mener, Martin, Clauss, Michael
• Primary Examiner(s): Williams, Arun
• Application Number:
  US14/882,571
• Publication Number:
  US 20160109528A1
• Time in Patent Office: 727 Days
• Field of Search: 324430
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

An apparatus and a method for determining an operating point-dependent change in resistance factor (AF_AP) of an energy storage device, wherein a start resistance is determined at an operating point start point in time, wherein a change in resistance between a present resistance of the energy storage device and the start resistance is determined at least at an operating point end point in time, wherein an end resistance is determined as a sum of the start resistance and the change in resistance determined at the operating point end point in time, wherein the operating point-dependent change in resistance factor (AF_AP) is determined as a ratio between the end resistance and a nominal resistance proportion of the start resistance, and to methods for determining an operating point-dependent resistance.

Claims

1. Method for determining an operating point-dependent change in resistance factor (AF_AP) of an energy storage device, wherein the method comprises:

determining a start resistance at an operating point start point in time,

determining a change in resistance between a present resistance of the energy storage device and the start resistance at least at an operating point end point in time,

determining an end resistance as a sum of the start resistance and the change in resistance determined at the operating point end point in time,

wherein the operating point-dependent change in resistance factor (AF_AP) is determined as a ratio between the end resistance and a nominal resistance proportion of the start resistance.

2. Method according to claim 1, wherein the start resistance is determined as a sum of a nominal resistance and an initial change in resistance.

3. Method according to claim 1, wherein the nominal resistance is determined in an operating point-dependent manner.

4. Method according to claim 1, wherein the initial change in resistance is constant for all operating points of a predetermined operating interval.

5. Method according to claim 1, wherein the change in resistance is determined repeatedly in the time period between the operating point start point in time and operating point end point in time, wherein the change in resistance is determined anew only if predetermined operating conditions are fulfilled.

6. Method according to claim 5, wherein the method further comprises:

storing the operating point-dependent change in resistance factor (AF_AP), wherein the storage of the operating point-dependent change in resistance factor (AF_AP) is effected only if a frequency of the determination of the change in resistance in the time period between the operating point start point in time and operating point end point in time exceeds a predetermined threshold value.

7. Method according to claim 1, wherein the method further comprises:

storing the operating point-dependent change in resistance factor (AF_AP), wherein time information about a determination point in time of the operating point-dependent change in resistance factor (AF_AP) is stored in addition to the operating point-dependent change in resistance factor (AF_AP).

8. Method according to claim 1, wherein the method further comprises:

storing the operating point-dependent change in resistance factor (AF_AP) in an indexed memory location of a first set (SM1) of memory locations which is addressed via an operating point-dependent index (IX), and/or storing the time information about a determination point in time of the operating point-dependent change in resistance factor (AF_AP) in an indexed memory location of a further set (SM2) of memory locations which is addressed via the operating point-dependent index (IX).

9. Method according to claim 1, wherein the method further comprises:

determining a temperature-normalized replacement change in resistance factor depending on the operating point-dependent change in resistance factor (AF_AP) and depending on an operating point temperature (T_AP).

10. Method according to claim 9, wherein the temperature-normalized replacement change in resistance factor is determined only if the operating point temperature (T_AP) lies in a predetermined temperature range.

11. Method according to claim 1, wherein the start resistance is determined depending on a presently stored operating point-dependent change in resistance factor (AF_AP).

12. Method according to claim 1, wherein the start resistance is determined depending on a presently stored operating point-dependent change in resistance factor (AF_AP) if a time duration between a present point in time and a determination point in time of the operating point-dependent change in resistance factor (AF_AP) determined last is less than or equal to a predetermined time duration,

wherein the start resistance is determined depending on a replacement change in resistance factor if the time duration between a present point in time and a determination point in time of the operating point-dependent change in resistance factor (AF_AP) determined last is greater than the predetermined time duration.

13. Method according to claim 12, wherein the replacement change in resistance factor is determined depending on a present operating point temperature (T_AP).

14. Method according to claim 1, wherein the change in resistance of the energy storage device is determined depending on the change over time in a deviation (Ue) between a model voltage and a measurement voltage (Umeas).

15. Method for determining an operating point-dependent resistance of an energy storage device, wherein the method comprises:

determining an operating point-dependent resistance depending on a presently stored operating point-dependent change in resistance factor (AF_AP), wherein the operating point-dependent change in resistance factor (AF_AP) is determined according to the steps;

determining a start resistance at an operating point start point in time,

determining a change in resistance between a present resistance of the energy storage device and the start resistance at least at an operating point end point in time,

determining an end resistance as a sum of the start resistance and the change in resistance determined at the operating point end point in time,

wherein the operating point-dependent change in resistance factor (AF_AP) is determined as a ratio between the end resistance and a nominal resistance proportion of the start resistance.

16. Method for determining an operating point-dependent resistance of an energy storage device, wherein the method comprises:

determining an operating point-dependent resistance depending on a presently stored operating point-dependent change in resistance factor (AF_AP) if a time duration between a present point in time and a determination point in time of the operating point-dependent change in resistance factor (AF_AP) determined last is less than or equal to a predetermined time duration,

wherein the operating point-dependent resistance is determined depending on a replacement change in resistance factor if the time duration between a present point in time and a determination point in time of the operating point-dependent change in resistance factor (AF_AP) determined last is greater than the predetermined time duration.

17. Apparatus for determining an operating point-dependent change in resistance factor (AF_AP) of an energy storage device, wherein the apparatus comprises:

at least one evaluation device,

wherein a start resistance is determinable at an operating point start point in time, wherein a change in resistance between a present resistance of the energy storage device and the start resistance is determinable at least at an operating point end point in time,

wherein an end resistance is determinable as a sum of the start resistance and the change in resistance determined at the operating point end point in time, and

wherein the operating point-dependent change in resistance factor (AF_AP) is determinable as a ratio between the end resistance and a nominal resistance proportion of the start resistance.