Apparatus for estimating battery degradation state, system including the same, and method thereof

• US 10,330,738 B2
• Filed: 07/18/2017
• Issued: 06/25/2019
• Est. Priority Date: 04/18/2017
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kim, Woo Sung
• Primary Examiner(s): Khuu, Hien D
• Application Number:
  US15/652,830
• Publication Number:
  US 20180299511A1
• Time in Patent Office: 707 Days
• Field of Search: 702 63
• 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 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• 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: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/371 with remote indication, e.g. on external chargers
• CPC Class Codes: G01R 31/3832 without measurement of battery voltage
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An apparatus for estimating a battery degradation state, a system including the same, and a method thereof are provided. The battery degradation state estimation system includes a battery degradation state estimation apparatus, implemented by a processor, that estimates a battery degradation state by using a correction coefficient calculated from a difference between a first open circuit voltage (OCV), calculated from battery state information, and a second open circuit voltage (OCV_i), acquired based on a change amount of a battery state of charge (SoC) determined by current integration, and a memory device that stores the first open circuit voltage (OCV), the second open circuit voltage (OCV_i), and the correction coefficient.

Claims

1. A system for estimating a battery degradation state, the system comprising:

a processor configured to estimate a battery degradation state by using a correction coefficient calculated from a difference between a first open circuit voltage (OCV), calculated from battery state information, and a second open circuit voltage (OCV_i), acquired based on a change amount of a battery state of charge (SoC) determined by current integration; and

a memory device configured to store the first open circuit voltage, the second open circuit voltage, and the correction coefficient,

wherein the processor is further configured to measure a terminal voltage of a battery equivalent model and subtract a voltage across an internal resistor and a phantom voltage component from the measured terminal voltage to calculate the first open circuit voltage.

2. The system of claim 1, wherein the battery state information includes:

voltage, temperature, and current.

3. The system of claim 2, wherein the processor is further configured to:

calculate the first open circuit voltage by using the battery state information and the battery equivalent model;

calculate a change amount of a battery state of charge (SoC) by integrating current of a battery;

calculate the second open circuit voltage corresponding to the change amount of the battery SoC by using a mapping table;

calculate the correction coefficient by using a difference between the first open circuit voltage and the second open circuit voltage; and

estimate a battery degradation degree by using the correction coefficient.

4. The system of claim 3, wherein the processor is further configured to measure the battery state information.

5. The system of claim 3, wherein the processor is further configured to calculate an open circuit voltage mapped to the change amount of the battery SoC and determine the calculated open circuit voltage as the second open circuit voltage by using the mapping table configured to map the open circuit voltage and the battery SoC.

6. The system of claim 3, wherein the processor is further configured to determine an open circuit voltage calculating condition and perform correction coefficient matching for calculation of the first open circuit voltage and the second open circuit voltage.

7. The system of claim 6, wherein the processor is further configured to determine whether the open circuit voltage calculating condition is satisfied according to current and voltage distribution degrees of the battery.

8. The system of claim 7, wherein the processor is configured to assume an initial voltage measured when a vehicle starts as an open circuit voltage and calculate the battery SoC depending on the assumed open circuit voltage, and

wherein, when a deviation between a current battery SoC and the battery SoC calculated based on the initial voltage exceeds a predetermined range, the processor is configured to determine that the correction coefficient matching is not satisfied.

9. The system of claim 1, further comprising:

a display device configured to display a driving distance according to the estimated battery degradation state and the estimated degradation degree.

10. A battery degradation state estimation apparatus comprising a processor configured to:

measure battery state information;

calculate a first open circuit voltage by using the measured battery state information and a battery equivalent model;

calculate a change amount of a battery state of charge (SoC) by integrating current of a battery;

calculate a second open circuit voltage corresponding to the change amount of the battery state of charge (SoC);

calculate a correction coefficient by using a difference of the first open circuit voltage and the second open circuit voltage; and

estimate a battery degradation degree by using the correction coefficient,

wherein the processor is further configured to measure a terminal voltage of the battery equivalent model and subtract a voltage across an internal resistor and a phantom voltage component from the measured terminal voltage to calculate the first open circuit voltage.

11. The apparatus of claim 10, wherein the processor is further configured to calculate an open circuit voltage mapped to the change amount of the battery SoC and determine the calculated open circuit voltage as the second open circuit voltage by using a mapping table configured to map the open circuit voltage and the battery SoC.

12. The apparatus of claim 10, wherein the processor is further configured to:

determine an open circuit voltage calculating condition and perform correction coefficient matching for calculation of the first open circuit voltage and the second open circuit voltage.

13. The apparatus of claim 12, wherein the processor is further configured to calculate the first open circuit voltage and the second open circuit voltage when the open circuit voltage calculating condition and the correction coefficient matching are satisfied.

14. A method of estimating a battery degradation state, the method comprising:

measuring, by a processor, battery state information;

calculating, by the processor, a first open circuit voltage using the measured battery state information and a battery equivalent model;

calculating, by the processor, a change amount of a battery state of charge (SoC) by integrating current of a battery;

calculating, by the processor, a second open circuit voltage corresponding to the change amount of the battery SoC by using a mapping table;

calculating, by the processor, a correction coefficient by using a difference between the first open circuit voltage and the second open circuit voltage; and

estimating, by the processor, a battery degradation degree by using the correction coefficient,

wherein the calculating of a first open circuit voltage includes;

measuring a terminal voltage of the battery equivalent model and subtracting a voltage across an internal resistor and a phantom voltage component from the measured terminal voltage to calculate the first open circuit voltage.

15. The method of claim 14, further comprising,

prior to the calculating of a first open circuit voltage, determining an open circuit voltage calculating condition and performing correction coefficient matching for calculation of the first open circuit voltage and the second open circuit voltage.

16. The method of claim 14, wherein the calculating of a second open circuit voltage includes:

calculating an open circuit voltage mapped to the change amount of the battery SoC and determining the calculated open circuit voltage as the second open circuit voltage by using the mapping table configured to map the open circuit voltage and the battery SoC.