Granted Patent B2

US 12,360,166 · App. 18/030,381 · Granted Jul 15, 2025

Inventors: Sun-Jong Lee (Daejeon, KR); Cheol-Taek Kim (Daejeon, KR); Yong-Chul Sung (Daejeon, KR)

Assignee: LG Energy Solution, Ltd.

G01R31/3648G01R31/007G01R31/3835

Abstract

Claims (43)

1. A battery diagnosis apparatus, comprising:

a voltage detector configured to measure a cell voltage of a battery cell; and

a control circuit configured to:

determine a plurality of sub-voltage curves by applying a moving window of a first time length to a reference voltage curve, the reference voltage curve being a time series of voltage values indicating the cell voltage measured at each sampling time for a predetermined period of time;

for each sub-voltage curve:

determine a long-term average voltage value of the sub-voltage curve using a first average filter of the first time length;

determine a short-term average voltage value of the sub-voltage curve using a second average filter of a second time length that is shorter than the first time length; and

determine a voltage deviation associated with the sub-voltage curve by calculating a difference between the long-term average voltage value and the short-term average voltage value of the sub-voltage curve; and

wherein the control circuit is configured to determine whether the battery cell is abnormal when any two of the plurality of voltage deviations determined for the plurality of sub-voltage curves meet a first requirement, a second requirement and a third requirement,

wherein the first requirement is that one of the two voltage deviations is equal to or larger than a first deviation threshold,

wherein the second requirement is that the other of the two voltage deviations is equal to or smaller than a second deviation threshold, and

wherein the third requirement is that a time interval between the two voltage deviations is equal to or smaller than a threshold time.

2. The battery diagnosis apparatus according to claim 1 , wherein the first deviation threshold is a positive number, and

wherein the second deviation threshold is a negative number of which an absolute value is equal to the first deviation threshold.

3. The battery diagnosis apparatus according to claim 1 , wherein the battery cell is abnormal when the voltage deviations of a predetermined number or more of sub-voltage curves among the plurality of sub-voltage curves are larger than the first deviation threshold or smaller than the second deviation threshold.

4. The battery diagnosis apparatus according to claim 1 , further comprising:

a current detector configured to measure a battery current flowing through the battery cell.

5. The battery diagnosis apparatus according to claim 4 , wherein the control circuit is configured to determine a plurality of sub-current curves by applying the moving window to a reference current curve, the reference current curve being a time series of current values indicating the battery current measured at each sampling time for the predetermined period of time, and

wherein the plurality of sub-current curves have a one-to-one correspondence with the plurality of sub-voltage curves.

6. The battery diagnosis apparatus according to claim 5 , wherein the control circuit is configured to, for each sub-current curve,

determine a current change which is a difference between a maximum current value and a minimum current value of the sub-current curve, and

determine the long-term average voltage value and the short-term average voltage value of the sub-voltage curve associated with the sub-current curve when the current change is smaller than a threshold change.

7. A battery pack comprising the battery diagnosis apparatus according to claim 1 .

8. An electric vehicle comprising the battery pack according to claim 7 .

9. A battery diagnosis method, comprising:

measuring, by a voltage detector, a cell voltage of a battery cell at each sampling time for a predetermined period of time;

determining, by a control circuit, a plurality of sub-voltage curves by applying a moving window of a first time length to a reference voltage curve, the reference voltage curve being a time series of voltage values indicating the cell voltage;

determining, by the control circuit for each sub-voltage curve, a long-term average voltage value of the sub-voltage curve using a first average filter of the first time length;

determining, by the control circuit for each sub-voltage curve, a short-term average voltage value of the sub-voltage curve using a second average filter of a second time length that is shorter than the first time length; and

determining, by the control circuit for each sub-voltage curve, a voltage deviation associated with the sub-voltage curve by calculating a difference between the long-term average voltage value and the short-term average voltage value of the sub-voltage curve; and

determining, by the control circuit, whether the battery cell is abnormal when any two of the plurality of voltage deviations determined for the plurality of sub-voltage curves meet a first requirement, a second requirement and a third requirement,

wherein the first requirement is that one of the two voltage deviations is equal to or larger than a first deviation threshold,

wherein the second requirement is that the other of the two voltage deviations is equal to or smaller than a second deviation threshold, and

wherein the third requirement is that a time interval between the two voltage deviations is equal to or smaller than a threshold time.

10. The battery diagnosis method according to claim 9 , wherein the battery cell is abnormal when the voltage deviation of a predetermined number or more of sub-voltage curves among the plurality of sub-voltage curves is larger than the first deviation threshold or smaller than the second deviation threshold.

11. The battery diagnosis method according to claim 9 , further comprising;

determining a plurality of sub-current curves by applying the moving window to a reference current curve, the reference current curve being a time series of current values indicating a battery current measured at each sampling time for the predetermined period of time, and

wherein the plurality of sub-current curves have a one-to-one correspondence with the plurality of sub-voltage curves.

12. The battery diagnosis method according to claim 11 , wherein, for each sub-current curve,

determining a current change which is a difference between a maximum current value and a minimum current value of the sub-current curve, and

determining the long-term average voltage value and the short-term average voltage value of the sub-voltage curve associated with the sub-current curve on a condition that the current change is smaller than a threshold change.

13. The battery diagnosis method according to claim 9 , wherein the first deviation threshold is a positive number, and

wherein the second deviation threshold is a negative number of which an absolute value is equal to the first deviation threshold.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (27)