Frequency based battery model parameter estimation

• US 9,132,745 B1
• Filed: 03/17/2014
• Issued: 09/15/2015
• Est. Priority Date: 03/17/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lee, Tae-Kyung
• Primary Examiner(s): Zanelli, Michael J
• Application Number:
  US14/215,308
• Publication Number:
  US 20150258907A1
• Time in Patent Office: 547 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• 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 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• 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 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• 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 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 7/14 : for vehicles propelled by ac motors
• CPC Class Codes: B60W 2050/0037 : Mathematical models of vehicle sub-units
• CPC Class Codes: B60W 2050/0052 : Filtering, filters
• CPC Class Codes: B60W 50/0098 : Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor

Abstract

A hybrid powertrain system includes a battery and at least one controller. The at least one controller is configured to determine instantaneous battery power limits during operation of the system using filtered battery voltage signals and current input signals. The at least one controller is further configured to separate medium-to-high frequency dynamics of the measured battery voltage. The filtering process, in certain examples, is realized using a low pass filter or a high pass filter. The at least one controller is further configured to correlate the medium-to-high frequency loads to estimate battery parameters and determine battery dynamics using, in one example, an Extended Kalman Filter.

Claims

1. A vehicle comprising:

a battery pack; and

at least one controller programmed to

control operation of the battery pack in response to (i) parameter values indicative of an internal resistance of the battery pack that are based on terminal voltage data of the battery pack having frequency content less than a threshold frequency and (ii) parameter values indicative of an internal impedance of the battery pack that are based on terminal voltage data of the battery pack having frequency content greater than the threshold frequency.

2. The vehicle of claim 1, wherein the internal resistance is an active electrolyte resistance of the battery pack.

3. The vehicle of claim 1, wherein the internal impedance includes a capacitance and an active charge transfer resistance of the battery pack.

4. The vehicle of claim 1, wherein the threshold frequency is based on electrochemical characteristics of the battery pack.

5. The vehicle of claim 1, wherein the at least one controller is further programmed to apply a frequency selective filter to obtain one of (i) the terminal voltage data of the battery back having frequency content greater than the threshold frequency or (ii) the terminal voltage data of the battery back having frequency content less than the threshold frequency.

6. The vehicle of claim 5, wherein the at least one controller is further programmed to generate the other of (i) the terminal voltage data of the battery back having frequency content greater than the threshold frequency and (ii) the terminal voltage data of the battery back having frequency content less than the threshold frequency based on a difference between an input voltage of the battery pack and the one of (a) the terminal voltage data of the battery back having frequency content greater than the threshold frequency or (b) the terminal voltage data of the battery back having frequency content less than the threshold frequency.

7. The vehicle of claim 1, wherein the at least one controller is further programmed to output a maximum discharge power available during predetermined periods based on the parameter values.

8. The vehicle of claim 1, wherein the at least one controller is further programmed to output a maximum charge power available during predetermined periods based on the parameter values.

9. A battery management method comprising:

controlling operation of a battery pack in response to parameter values indicative of an internal resistance of the battery pack that are based on terminal voltage data of the battery pack having frequency content less than a threshold frequency and in response to parameter values indicative of an internal impedance of the battery pack that are based on the terminal voltage data having frequency content greater than the threshold frequency.

10. The method of claim 9, wherein the internal resistance is an active electrolyte resistance of the battery pack.

11. The method of claim 9, wherein the internal impedance includes a charged capacitance and active charge resistance of the battery pack.

12. The method of claim 9, wherein the threshold frequency is based on electrochemical characteristics of the battery pack.

13. The method of claim 9, further comprising applying a frequency selective filter to obtain one of (i) the terminal voltage data of the battery back having frequency content greater than the threshold frequency or (ii) the terminal voltage data of the battery back having frequency content less than the threshold frequency.

14. The method of claim 13, further comprising generating the other of (i) the terminal voltage data of the battery back having frequency content greater than the threshold frequency and (ii) the terminal voltage data of the battery back having frequency content less than the threshold frequency based on a difference between an input voltage of the battery pack and the one of (a) the terminal voltage data of the battery back having frequency content greater than the threshold frequency or (b) the terminal voltage data of the battery back having frequency content less than the threshold frequency.

15. The method of claim 9, further comprising outputting a maximum discharge power available during predetermined periods based on the parameter values or a maximum charge power available during predetermined periods based on the parameter values.

16. A hybrid powertrain system comprising:

a battery pack having one or more battery cells; and

at least one controller programmed to

implement a model of the battery pack,

filter terminal voltage data of the battery pack into high-frequency content having frequencies greater than a threshold and low-frequency content having frequencies less than the threshold, and

control operation of the battery pack in response to predicted available battery power derived from (i) parameter values indicative of an internal resistance of the battery pack that are based on the low-frequency content and (ii) parameter values indicative of an internal impedance of the battery pack that are based on the high-frequency content.

17. The hybrid powertrain system of claim 16, wherein the internal resistance is an active electrolyte.

18. The hybrid powertrain system of claim 16, wherein the internal impedance includes a capacitance and an active charge transfer resistance.

19. The hybrid powertrain system of claim 16, wherein the predicted available battery power includes a maximum discharge power available during predetermined periods.