APPARATUS AND METHOD FOR ESTIMATING DETERIORATION OF BATTERY PACK

• US 20150268309A1
• Filed: 03/12/2015
• Published: 09/24/2015
• Est. Priority Date: 03/20/2014
• Status: Active Grant

• Current Assignee: Hyundai Mobis Co., Ltd.
• Original Assignee: Hyundai Mobis Co., Ltd.
• Inventors: Kim, Tae-Kwon
• Granted Patent: US 9,714,984 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

An apparatus for estimating a deterioration may include a battery pack, a state information sensing unit configured to sense a state of the battery pack to generate state information, a conversion operation unit configured to convert into an open circuit voltage (OCV) using the generated state information and estimate a state of charge (SOC) using the converted OCV, a first SOH estimation operation unit configured to estimate a first state of charge (SOH) using the estimated SOC, a battery aging factor calculation unit configured to calculate a battery aging factor using the estimated SOC, a second SOH operation unit configured to apply the calculated battery aging factor to a preset lookup table to calculate a second SOH, and a filtering unit configured to filter the first SOH and the second SOH to generate a final SOH.

Claims

1. An apparatus for estimating deterioration, comprising:

a battery pack;

a state information sensing unit configured to sense a state of the battery pack to generate state information;

a conversion operation unit configured to convert into an open circuit voltage (OCV) using the generated state information and estimate a state of charge (SOC) value using the converted OCV;

a first SOH estimation operation unit configured to estimate a first state of charge (SOH) value using the estimated SOC value;

a battery aging factor calculation unit configured to calculate a battery aging factor using the estimated SOC value;

a second SOH operation unit configured to apply the calculated battery aging factor to a preset lookup table to calculate a second SOH value; and

a filtering unit configured to filter the first SOH value and the second SOH value to generate a third SOH value.

2. The apparatus of claim 1, wherein the state information includes voltage, temperature, and current.

3. The apparatus of claim 1, wherein the SOC value is estimated by converting the OCV into the SOC value using a preset SOC-OCV lookup table.

4. The apparatus of claim 1, wherein the SOC value is estimated by converting the OCV into the SOC value using a coulomb counting scheme and the coulomb counting scheme represents a value obtained by integrating a current value input by a unit time and then dividing the integrated current value by the total battery capacity as the SOC value fluctuates for a unit time.

5. The apparatus of claim 1, wherein the first estimation operation unit primarily estimates the SOH value using a charge transfer and an SOC change value for a predetermined time by using a change in the SOC value depending on a current behavior at the time of charging and discharging of the battery pack.

6. The apparatus of claim 5, wherein the first estimation operation unit calculates the first SOH value by assigning a threshold condition to the primarily estimated SOH value and applying a least mean square scheme to the SOH satisfying the threshold condition.

7. The apparatus of claim 6, wherein the first SOH value is estimated by being divided by an initial battery capacity at a linear slope calculated by the least mean square scheme to be obtained as a percentage.

8. The apparatus of claim 1, wherein the preset lookup table is an SOH lookup table for each SOC value section.

9. The apparatus of claim 1, wherein the third SOH is calculated by Equation FINAL SOH−

A×

SOH_OPERATION+(1−

A)×

SOH_table (Here, FINAL SOH represents the third SOH value, SOH_operation represents the first SOH, SOH_table represents the second SOH, and A represents a value changed depending on temperature).

10. The apparatus of claim 9, wherein A represents one selected from values which are tabulated by a database storing temperature information through experiments.

11. A method of determining deterioration of a battery pack, comprising:

sensing voltage and current of a battery pack;

estimating an open circuit voltage (OCV) using the sensed voltage and current;

estimating a state of charge (SOC) value using the computed OCV;

estimating a first state of health (SOH) value using the estimated SOC value and a SOH estimating formula;

estimating a battery aging factor using the estimated SOC value;

applying the calculated battery aging factor to a preset lookup table for acquiring a second SOH value; and

estimating a third SOH value using the first SOH value and the second SOH value thereby determining deterioration of the battery pack using the third SOH value.

12. The method of claim 11, further comprising sensing a temperature of the battery pack to be used when estimating the SOC value.

13. The method of claim 11, wherein the SOC value is acquired by converting the OCV into the SOC value using a preset SOC-OCV lookup table.

14. The method of claim 13, wherein the SOC is estimated by converting the OCV into the SOC value using a coulomb counting scheme and the coulomb counting scheme represents a value obtained by integrating a current value input by a unit time and then dividing the integrated current value by the total battery capacity as the SOC value fluctuates for a unit time.

15. The method of claim 11, wherein in the estimating of the first state of charge, the SOH value is primarily estimated using a charge transfer and an SOC change value for a predetermined time by using a change in the SOC value depending on a current behavior at the time of charging and discharging of the battery pack.

16. The method of claim 15, wherein in the first state of charge, the first SOH value is calculated by assigning a threshold condition to the primarily estimated SOH value and applying a least mean square scheme to the SOH value satisfying the threshold condition.

17. The method of claim 16, wherein the first SOH value is estimated by being divided by an initial battery capacity at a linear slope calculated by the least mean square scheme to be obtained as a percentage.

18. The method of claim 11, wherein the preset lookup table is an SOH lookup table for each SOC value section.

19. The method of claim 11, wherein the third SOH value is calculated by Equation FINAL SOH=A×

SOH_OPERATION+(1−

A)×

SOH_table (In the above Equation, FINAL SOH represents the third SOH value, the SOH_operation represents the first SOH value, SOH_table represents the second SOH value, and A represents a value changed depending on temperature).

20. The method of claim 19, wherein A represents one selected from values which are tabulated by a database storing temperature information through experiments.