Apparatus and method for estimating state of health of vehicle battery

1. An apparatus for estimating a state of health (SOH) of a battery, the apparatus comprising:

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

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

a first SOH estimation operation unit configured to estimate a first state of health (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 calculate a second SOH value using the calculated battery aging factor and a predetermined lookup table; and

a filtering unit configured to to generate a third SOH value using the following equation:

FINAL SOH= A ×SOH OPERATION +(1 −A )×SOH table ,

wherein “FINAL SOH” represents the third SOH value,

“SOH operation ” represents the first SOH,

“SOH table ” represents the second SOH, and

“A” represents a value that changes depending upon temperature of the battery.

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 predetermined 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 is configured to estimate 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 is further configured to calculate 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 as a percentage divided by an initial battery capacity at a linear slope calculated by the least mean square scheme.

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

9. The apparatus of claim 1 , wherein A represents one selected from values which are tabulated by a database storing temperature information through experiments.

10. A method of estimating a state of health (SOH) of a battery pack, comprising:

sensing voltage and current of the 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 predetermined lookup table for acquiring a second SOH value; and

estimating a third SOH value using the following equation:

FINAL SOH= A ×SOH OPERATION +(1 −A )×SOH table ,

wherein “FINAL SOH” represents the third SOH value,

“SOH operation ” represents the first SOH,

“SOH table ” represents the second SOH, and

“A” represents a value that changes depending upon temperature of the battery.

11. The method of claim 10 , further comprising sensing a temperature of the battery pack to be used when estimating the SOC value.

12. The method of claim 10 , wherein the SOC value is acquired by converting the OCV into the SOC value using a predetermined SOC-OCV lookup table.

13. The method of claim 12 , 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.

14. The method of claim 10 , 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.

15. The method of claim 14 , 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.

16. The method of claim 15 , 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.

17. The method of claim 10 , wherein the predetermined lookup table is an SOH lookup table for each SOC value section.

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