Device and method for determining state of battery pack

Patent metadata

Field	Value
Publication number	US-12596155-B2
Application number	US-202318314246-A
Country	US
Kind code	B2
Filing date	May 9, 2023
Priority date	Apr 21, 2020
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

A parameter ratio that is a ratio of a parameter of a parallel-cell block to be determined to an average value of parameters of a plurality of parallel-cell blocks is calculated, a moving-average value of the parameter ratio is obtained, and a state of the parallel-cell block to be determined is determined based on an index value that is a difference between the parameter of the parallel-cell block to be determined and the moving-average value.

First claim

What is claimed is:

1 . A device that determines a state of a battery pack comprising three or more series-connected parallel-cell blocks each including a plurality of cells connected in parallel, comprising:
a voltage sensor that detects an inter-terminal voltage of the parallel-cell block; a current sensor that detects that detects amount of the current flowing through the parallel-cell block; a processor configured to execute machine readable instructions to: obtain a parameter indicating a state of the parallel-cell block; calculate a parameter ratio that is a ratio of a parameter of a parallel-cell block to be determined to an average value of parameters of a plurality of parallel-cell blocks; calculate a moving-average value of the parameter ratio; obtain an index value that is a difference between the parameter ratio of the parallel-cell block to be determined and the moving-average value of the parameter ratio; determine a state of the parallel-cell block to be determined, based on the index value; and provide warning information indicating that abnormal degradation is caused when it is determined that the index value exceeds a threshold value; wherein the parameter indicating a state of the parallel-cell block includes the inter-terminal voltage detected by the voltage sensor and the amount of the current flowing detected by the current sensor, the processor obtains the parameter of the parallel-cell block to be determined whenever a predetermined time arrives, calculates the index value based on a moving-average value of the parameter ratio calculated using a parameter of the parallel-cell block to be determined obtained when the predetermined time immediately previously arrives and a parameter of the parallel-cell block to be determined obtained when the predetermined time currently arrives; as the plurality of parallel-cell blocks subject to calculation of the average value, parallel-cell blocks close in temperature to the parallel-cell block to be determined are selected; the processor obtains the parameter of the parallel-cell block to be determined whenever a predetermined time arrives; the temperature of the parallel-cell block to be determined is that of the parallel-cell block to be determined at the predetermined time; the battery pack is a battery pack mounted in a vehicle; the predetermined time is any one of: when the battery pack is externally charged; when an amount of power stored in the battery pack reaches a predetermined value while the vehicle is traveling; when the vehicle starts traveling; and when the vehicle ends traveling; and an inlet is connected to the battery pack, and the battery pack is charged by electric power supplied from the inlet.

2 . The device that determines a state of a battery pack according to claim 1 , wherein the processor calculates a second parameter ratio that is the ratio of the parameter of the parallel-cell block to be determined to an average value of parameters of a plurality of parallel-cell blocks excluding the parallel-cell block to be determined.

3 . The device that determines a state of a battery pack according to claim 1 , wherein the parameter of the parallel-cell block to be determined is at least one of an internal resistance of the parallel-cell block of the parallel-cell block to be determined, an amount of self-discharge by the parallel-cell block of the parallel-cell block to be determined, and a cell capacity of the parallel-cell block of the parallel-cell block to be determined.

4 . The device that determines a state of a battery pack according to claim 1 , wherein the processor determines a degraded state of the parallel-cell block to be determined, based on the index value, and determines the degraded state of the parallel-cell block to be determined, based on the parameter of the parallel-cell block to be determined.

5 . The device that determines a state of a battery pack according to claim 1 , wherein the processor outputs at least one of warning information and identification information of the parallel-cell block to be determined when it is determined that the index value deviates from a predetermined range.

6 . A method for determining a state of a battery pack comprising three or more series-connected parallel-cell blocks each including a plurality of cells connected in parallel, the method comprising:
obtaining a parameter indicating a state of the parallel-cell block; calculating a parameter ratio that is a ratio of a parameter of a parallel-cell block to be determined to an average value of parameters of a plurality of parallel-cell blocks; calculating a moving-average value of the parameter ratio; obtaining an index value that is a difference between the parameter ratio of the parallel-cell block to be determined and the moving-average value; determining a state of the parallel-cell block to be determined, based on the index value; calculating the index value based on a moving-average value of the parameter ratio calculated using a parameter of the parallel-cell block to be determined obtained when the predetermined time immediately previously arrives and a parameter of the parallel-cell block to be determined obtained when the predetermined time currently arrives; as the plurality of parallel-cell blocks subject to calculation of the average value, selecting parallel-cell blocks close in temperature to the parallel-cell block to be determined; obtaining the parameter of the parallel-cell block to be determined whenever a predetermined time arrives; the temperature of the parallel-cell block to be determined is that of the parallel-cell block to be determined at the predetermined time; the battery pack is a battery pack mounted in a vehicle; the predetermined time is any one of: when the battery pack is externally charged; when an amount of power stored in the battery pack reaches a predetermined value while the vehicle is traveling; when the vehicle starts traveling; and when the vehicle ends traveling; and charging the battery pack by electric power supplied from an inlet connected to the battery pack.

7 . The method for determining a state of a battery pack according to claim 6 , wherein the calculating a parameter ratio includes calculating a second parameter ratio that is the ratio of the parameter of the parallel-cell block to be determined to an average value of parameters of a plurality of parallel-cell blocks excluding the parallel-cell block to be determined.

Assignees

• Toyota Jidosha Kk

Inventors

• Imade Yuki
• Migita Tsubasa

Classifications

• H02J7/80 Primary

  including monitoring or indicating arrangements · CPC title

• G01R31/392

  Determining battery ageing or deterioration, e.g. state of health · CPC title

• G01R31/382

  Arrangements for monitoring battery or accumulator variables, e.g. SoC · CPC title

• G01R31/396 Primary

  Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery · CPC title

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title