System and method for energy prediction in battery packs

• US 9,360,527 B2
• Filed: 08/09/2012
• Issued: 06/07/2016
• Est. Priority Date: 08/12/2011
• Status: Active Grant

• Current Assignee: CPS Technology Holdings, LLC
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Jin, Zhihong H., Elberson, Matthew D., Boone, David R., Kasavajjila, Uday S.
• Primary Examiner(s): Mawari, Redhwan K
• Assistant Examiner(s): King, Rodney P
• Application Number:
  US13/571,133
• Publication Number:
  US 20130041538A1
• Time in Patent Office: 1,398 Days
• Field of Search: 701/22, 324/427, 903/930
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2250/18 by enquiring driving style
• CPC Class Codes: B60L 2260/52 drive range estimation, e.g. of estimation of available travel distance
• CPC Class Codes: B60L 2260/54 Energy consumption estimation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

In an embodiment, a system includes a battery management unit (BMU) coupled to a battery pack of an xEV. Further, the BMU is configured to determine an energy remaining value for the battery pack based, at least in part, on a minimum cell temperature and a minimum cell state of charge percentage (SOC %) determined by the BMU for the battery pack.

Claims

1. A battery management unit (BMU) system communicatively coupled to a plurality of sensors respectively associated with a plurality of battery cells of a battery pack of an xEV, wherein the BMU system is configured to:

receive, from the plurality of sensors, a first plurality of signals and a second plurality of signals, wherein each of the first plurality of signals is indicative of a present temperature of a respective one of the plurality of battery cells and wherein each of the second plurality of signals is indicative of a present state of charge (SOC) of the respective one of the plurality of battery cells;

determine a plurality of temperatures based on the first plurality of signals, wherein each of the plurality of temperatures respectively corresponds to a present battery cell temperature of a single battery cell of the plurality of battery cells;

determine a plurality of SOC percentages based on the second plurality of signals, wherein each of the plurality of SOC percentages respectively corresponds to a present SOC percentage of a single one of the plurality of battery cells;

determine a lowest cell temperature from the plurality of temperatures and a lowest cell SOC percentage from the plurality of SOC percentages; and

determine an energy remaining value for the battery pack based on the lowest cell temperature and the lowest cell SOC percentage.

2. The BMU system of claim 1, wherein the BMU system is configured to provide the determined energy remaining value to a vehicle control unit (VCU) that controls operation of the xEV, and wherein the VCU is configured to determine a range remaining for the xEV in distance, time, or both, based, at least in part, on the energy remaining value provided by the BMU system.

3. The BMU system of claim 2, wherein the VCU is configured to instruct an instrument cluster to display the range remaining for the xEV in distance, time, or both.

4. The BMU system of claim 1, wherein the BMU system is configured to use one or more look-up tables to determine the energy remaining value.

5. The BMU system of claim 4, wherein the one or more look-up tables comprise at least one table relating the lowest cell SOC percentage to an average cell voltage of the battery pack.

6. The BMU system of claim 4, wherein the one or more look-up tables comprise at least one table relating both the lowest cell SOC percentage and the lowest cell temperature to a discharge resistance of the battery pack.

7. The BMU system of claim 4, wherein the one or more look-up tables comprise at least one table relating both the lowest cell SOC percentage and the lowest cell temperature to a beginning of life (BOL) energy remaining value for the battery pack.

8. The BMU system of claim 7, wherein the BMU system is configured to determine the energy remaining value for the battery pack using the BOL energy remaining value and a weighting factor.

9. The BMU system of claim 8, wherein the weighting factor is based on a calendar or cycle life of the battery pack or based on a real-time aging determination algorithm.

10. The BMU system of claim 1, wherein the BMU system is configured to determine the energy remaining value using an average cell voltage, a discharge resistance, a discharge voltage, and a remaining SOC percentage of the battery pack.

11. The BMU system of claim 1, wherein the BMU system is configured to determine the energy remaining value using a cell capacity, a number of battery cells, a discharge current, and a lower limit SOC percentage of the battery pack.

12. The BMU system of claim 1, wherein the BMU system is configured to determine the energy remaining value using a cell resistance aging factor that is based on a calendar or cycle life of the battery pack or based on a real time aging determination algorithm.

13. The BMU system of claim 1, wherein the BMU system determines the energy remaining value using a driving profile weighting factor that is based on a driving style typical for the xEV to experience.

14. A system, comprising:

a battery pack for an xEV, comprising;

a plurality of electrochemical cells;

a plurality of sensors respectively associated with the plurality of electrochemical cells and configured to generate a first plurality of signals and a second plurality of signals, wherein each of the first plurality of signals is indicative of a present temperature of a respective one of the plurality of electrochemical cells and wherein each of the second plurality of signals is indicative of a present state of charge (SOC) percentage of a single one of the plurality of electrochemical cells; and

a battery management unit (BMU) coupled to the battery pack and the plurality of sensors and configured to;

determine a plurality of temperatures based on the first plurality of signals, wherein each of the plurality of temperatures corresponds to a present cell temperature of a single electrochemical cell;

determine a plurality of SOC percentages based on the second plurality of signals, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of electrochemical cells;

determine a lowest cell temperature from the plurality of temperatures and a lowest cell SOC percentage from the plurality of SOC percentages; and

determine an energy remaining in the plurality of electrochemical cells using the lowest cell temperature and the lowest cell SOC percentage.

15. The system of claim 14, wherein the BMU is configured to determine the energy remaining in the plurality of electrochemical cells using a cell resistance aging factor that is based on a calendar or cycle life of the plurality of electrochemical cells or based on a real time aging determination algorithm.

16. The system of claim 14, wherein the BMU is configured to determine or receive a driving profile weighting factor from a vehicle control unit (VCU) that controls operation of the xEV, and configured to use the driving profile weighting factor to determine the energy remaining in the plurality of electrochemical cells.

17. The system of claim 16, wherein the BMU is configured to communicate to the VCU a value corresponding to the energy remaining in the plurality of electrochemical cells.

18. The system of claim 17, wherein the VCU is configured to receive, from the BMU, the value corresponding to the energy remaining in the plurality of electrochemical cells, and configured to use the value to determine a time, a distance, or a combination thereof, that the xEV may travel by consuming the remaining energy in the plurality of electrochemical cells.

19. The system of claim 18, wherein the VCU is configured to instruct an instrument cluster to display the time, the distance, or a combination thereof, that the xEV may travel by consuming the remaining energy in the plurality of electrochemical cells.

20. An xEV, comprising:

a battery pack having a plurality of battery cells and configured to supply electrical power to propel the xEV;

a battery management unit (BMU) configured to monitor and control the battery pack; and

a vehicle control unit (VCU) communicatively coupled to the BMU, wherein the BMU, the VCU, or a combination thereof, is configured to;

determine a plurality of temperatures, wherein each of the plurality of temperatures corresponds to a present battery cell temperature of a single battery cell;

determine a plurality of state of charge (SOC) percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of battery cells; and

determine an energy remaining value for the battery pack based on only a lowest cell temperature of the plurality of temperatures and only a lowest SOC percentage of the plurality of SOC percentages.

21. The system of claim 20, wherein the VCU is configured to determine a remaining range of the xEV using the determined energy remaining value and configured to instruct an instrument cluster to display the determined remaining range of the xEV.

22. The system of claim 20, comprising an internal combustion engine, a generator, and a fuel tank storing fuel, wherein the internal combustion engine is configured to combust the fuel from the fuel tank to power the generator, and wherein the generator is configured supply electrical power to the battery pack.

23. The system of claim 22, wherein the VCU is configured to determine an amount of energy that the fuel in the fuel tank of the xEV will provide to the battery pack when the fuel is combusted by the internal combustion engine.

24. The system of claim 23, wherein the VCU is configured to determine a remaining range of the xEV based, at least in part, on the determined energy remaining value for the battery pack and the determined amount of energy that the fuel from the fuel tank of the xEV will provide and configured to instruct an instrument cluster to display the determined remaining range of the xEV.

25. A method, comprising:

determining an amount of energy remaining in a battery pack of an xEV, wherein the battery pack comprises a plurality of cells, and wherein the amount of energy remaining in the battery pack is determined using a discharge voltage of the battery pack, a state of charge (SOC) percentage remaining for the battery pack, a number of the plurality of cells in the battery pack, and an actual cell capacity of each of the plurality of cells of the battery pack.

26. The method of claim 25, comprising determining the SOC percentage remaining for the battery pack using a SOC percentage lower limit of the battery pack, a driving profile weighting factor, and a lowest cell SOC percentage of a plurality of SOC percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of battery cells.

27. The method of claim 26, wherein the driving profile weighting factor is based on a driving style experienced by the xEV.

28. The method of claim 25, comprising determining the discharge voltage of the battery pack using an average cell voltage of the battery pack, a cell resistance aging factor of the battery pack, a discharge resistance of the battery pack, and a measured discharge current of the battery pack.

29. The method of claim 28, comprising determining the average cell voltage for the battery pack using a lowest measured cell SOC percentage of a plurality of SOC percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of cells.

30. The method of claim 29, wherein determining the average cell voltage of the battery pack comprises using a look-up table that correlates the lowest measured cell SOC percentage and the average cell voltage of the battery pack.

31. The method of claim 28, comprising determining the discharge resistance of the battery pack using:

a lowest cell SOC percentage of a plurality of SOC percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of cells; and

a lowest cell temperature of a plurality of cell temperatures, wherein each of the plurality of cell temperatures corresponds to a present cell temperature of a single cell of the plurality of cells.

32. The method of claim 31, wherein determining the discharge resistance of the battery pack comprises using a look-up table that correlates the lowest cell SOC percentage, the lowest cell temperature, and the discharge resistance of the battery pack.

33. The method of claim 28, comprising determining the cell resistance aging factor of the battery pack using a calendar or cycle life of the battery pack.

34. A method, comprising:

determining an amount of energy remaining in a battery pack that includes a plurality of cells, comprising;

receiving, from a plurality of sensors, a first plurality of signals and a second plurality of signals, wherein each of the first plurality of signals is indicative of a present temperature of a respective one of the plurality of battery cells and wherein each of the second plurality of cells is indicative of a present state of charge (SOC) of the respective one of the plurality of battery cells;

determining a plurality of measured cell temperatures based on the first plurality of signals, wherein each of the plurality of measured cell temperatures corresponds to a present cell temperature of a single cell of the plurality of cells;

determining a plurality of measured cell state of charge (SOC) percentages based on the second plurality of signals, wherein each of the plurality of measured cell SOC percentages corresponds to a present cell SOC percentage of a single one of the plurality of cells;

determining a lowest cell temperature from the plurality of measured cell temperatures and a lowest cell state of charge (SOC) percentage from the plurality of measured cell SOC percentages;

determining an average cell voltage of the battery pack using the lowest SOC percentage;

determining a discharge resistance of the battery pack using the lowest cell temperature and the lowest SOC percentage;

determining a discharge voltage of the battery pack using the average cell voltage of the battery pack;

determining a SOC percentage remaining for the battery pack using the lowest cell SOC percentage; and

determining the amount of energy remaining in the battery pack using the discharge voltage of the battery pack and the SOC percentage remaining for the battery pack.

35. The method of claim 34, wherein the discharge voltage of the battery pack is determined using the average cell voltage of the battery pack, the discharge resistance of the battery pack, a measured discharge current of the battery pack, and a cell resistance aging factor of the battery pack.

36. The method of claim 35, comprising using look-up tables to determine the average cell voltage and the discharge resistance of the battery using only the lowest cell temperature and the lowest cell SOC percentage as inputs.

37. The method of claim 35, comprising determining the cell resistance aging factor of the battery pack using a calendar or cycle life of the battery pack.

38. The method of claim 35, wherein the SOC percentage remaining for the battery pack is determined using the lowest cell SOC percentage, a SOC percentage lower limit of the battery pack, and a driving profile weighting factor.

39. The method of claim 38, comprising determining the driving profile weighting factor using information indicative of a typical driving style experienced by the xEV.

40. The method of claim 38, wherein the amount of energy remaining in the battery pack is determined using the discharge voltage of the battery pack, the SOC percentage remaining for the battery pack, a number of the plurality of cells of the battery pack, and an actual cell capacity of each of the plurality of cells of the battery pack.

41. A method, comprising:

determining an amount of energy remaining in a battery pack of an xEV, wherein the battery pack comprises a plurality of cells, and wherein the amount of energy remaining is determined from a plurality of inputs consisting essentially of;

a number of the plurality of cells in the battery pack;

an actual cell capacity of each of the plurality of cells of the battery pack;

a discharge current of the battery pack;

a cell resistance aging factor of the battery pack;

a driving profile weighting factor;

a lowest state of charge (SOC) percentage of a plurality of SOC percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of cells; and

a lowest cell temperature of a plurality of cell temperatures, wherein each of the plurality of cell temperatures corresponds to a present cell temperature of a single cell of the plurality of cells.

42. The method of claim 41, comprising measuring or estimating the actual cell capacity of each of the plurality of cells of the battery pack.

43. The method of claim 41, comprising measuring, estimating, or predetermining the discharge current of the battery pack.

44. The method of claim 41, comprising measuring the cell resistance aging factor of the battery pack or estimating the cell resistance aging factor of the battery pack based on a calendar or cycle life of the batter pack.

45. The method of claim 41, comprising determining the driving profile weighting factor based on a typical driving style experienced by the xEV.

46. A method, comprising:

determining an amount of energy remaining in a battery pack of an xEV, wherein the battery pack comprises a plurality of cells, and wherein the amount of energy remaining is determined from a plurality of inputs consisting essentially of;

a number of the plurality of cells in the battery pack;

a weighting factor based on a calendar or cycle life of the battery pack;

a lowest state of charge (SOC) percentage of a plurality of SOC percentages, wherein each of the plurality of SOC percentages corresponds to a present SOC percentage of a single one of the plurality of cells; and

a lowest cell temperature of a plurality of cell temperatures, wherein each of the plurality of cell temperatures corresponds to a present cell temperature of a single cell of the plurality of cells.