Granted Patent B2

US 12,724,079 · App. 18/564,582 · Granted Sep 1, 2026

Inventors: Noboru Oyama (Tokyo, JP); Shuichiro Yamaguchi (Tokyo, JP); Yasuhiko Ohsawa (Tokyo, JP); Yasumasa Mochizuki (Tokyo, JP); Rin Furudate (Tokyo, JP); Hiroshi Abe (Tokyo, JP)

Assignee: SUBARU CORPORATION

G01R31/3842G01R31/378G01R31/392H01M10/4285

Abstract

Claims (34)

1 . A battery diagnosis apparatus for diagnosing a state of a battery, the battery diagnosis apparatus comprising:

a current source configured to apply a pulse current to the battery;

a voltage sensor configured to detect a voltage between terminals of the battery;

a temperature sensor configured to detect a temperature of the battery;

an SOC adjustment device configured to adjust an SOC of the battery; and

a control device, wherein

the control device comprises:

one or more processors; and

one or more memories coupled to the one or more processors, and

the one or more processors are configured to execute processing comprising:

deriving a present SOC of the battery before the pulse current is applied to the battery;

when the present SOC of the battery is greater than an upper limit of a predetermined range before the pulse current is applied to the battery, causing the SOC adjustment device to receive electric power from the battery to reduce the SOC of the battery, and when the present SOC of the battery is lower than a lower limit of the predetermined range before the pulse current is applied to the battery, causing the SOC adjustment device to supply electric power to the battery to increase the SOC of the battery;

acquiring the temperature of the battery before the pulse current is applied to the battery;

determining a determination criterion for determining a degree of deposition of lithium in the battery, based on the temperature of the battery before the pulse current is applied to the battery;

applying a plurality of the pulse currents having different current values to the battery in stages to acquire respective voltage responses corresponding to the current values;

deriving, from the respective voltage responses, respective indices corresponding to the current values, each index indicating a comparison between an on-ATRF and an off-ATRF, the on-ATRF being an apparent transient resistance function of the battery when a corresponding one of the pulse currents is turned on, the off-ATRF being an apparent transient resistance function of the battery when the corresponding one of the pulse currents is turned off, the on-ATRF being at a timing at which a specific time has elapsed from a timing of a rising edge of a voltage in response to turning on of the corresponding one of the pulse currents, the off-ATRF being at a timing at which the specific time has elapsed from a timing of a falling edge of the voltage in response to turning off of the corresponding one of the pulse currents; and

comparing the determined determination criterion with the respective indices corresponding to the current values to determine the degree of deposition of lithium in the battery, based on the respective indices corresponding to the current values.

2 . The battery diagnosis apparatus according to claim 1 , wherein each index is a resistance function ratio indicating a ratio of the off-ATRF to the on-ATRF.

3 . The battery diagnosis apparatus according to claim 1 , wherein

in the deriving of the indices, the one or more processors are configured to execute processing comprising, for each of the current values, deriving a plurality of the indices having different specific times, and

in the determining of the degree of deposition of lithium in the battery, the one or more processors are configured to execute processing comprising determining the degree of deposition of lithium in the battery, based on respective average values of the indices for the current values.

4 . The battery diagnosis apparatus according to claim 2 , wherein each index indicates a comparison between the on-ATRF at a timing at which a specific time has elapsed from a timing of a rising edge of a voltage in response to turning on of a corresponding one of the pulse currents and the off-ATRF at a timing at which the specific time has elapsed from a timing of a falling edge of the voltage in response to turning off of the corresponding one of the pulse currents.

5 . The battery diagnosis apparatus according to claim 4 , wherein

in the deriving of the indices, the one or more processors are configured to execute processing comprising, for each of the current values, deriving a plurality of the indices having different specific times, and

in the determining of the degree of deposition of lithium in the battery, the one or more processors are configured to execute processing comprising determining the degree of deposition of lithium in the battery, based on respective average values of the indices for the current values.

6 . The battery diagnosis apparatus according to claim 1 , wherein

the one or more memories store a plurality of determination criterion tables corresponding to respective temperatures of the battery, and

the one or more processors are further configured to execute processing comprising selecting one of the determination criterion tables based on the temperature of the battery.

7 . The battery diagnosis apparatus according to claim 1 , wherein the one or more processors are further configured to execute processing comprising:

after deriving the on-ATRF and the off-ATRF, determining whether the on-ATRF or the off-ATRF is an abnormal value; and

when the on-ATRF or the off-ATRF is determined to be the abnormal value, omitting derivation of the index and determination of a current-value-specific SLDT indicating the degree of deposition of lithium in the battery, and excluding the abnormal value from a target from which a total SLDT indicating the degree of deposition of lithium in the battery is to be derived.

8 . The battery diagnosis apparatus according to claim 1 , wherein the one or more processors are configured to execute processing comprising:

after determining the degree of deposition of lithium in the battery for one of the current values, determining whether a measurement completion condition is satisfied; and

when the measurement completion condition is not satisfied, determining another current value from among candidate current values for which determination of a current-value-specific SLDT indicating the degree of deposition of lithium in the battery is not completed, and causing the current source to apply a pulse current having the another current value to the battery.

Assignments (1)

Continuity (1)

References Cited (17)