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EP-4530650-B1 - METHOD AND APPARATUS FOR ESTIMATION AND VISUALIZATION OF CONSISTENCY FOR POWER BATTERY

EP4530650B1EP 4530650 B1EP4530650 B1EP 4530650B1EP-4530650-B1

Inventors

  • KAN, Yuyan
  • WANG, Enqun
  • FANG, XIN
  • SHEN, BIN

Dates

Publication Date
20260513
Application Date
20240925

Claims (15)

  1. A method for estimating consistency for power battery, the power battery is composed of a plurality of cells and is configured to provide energy for a vehicle, and the method (S100) comprising: detecting operating voltages for each cell of the plurality of cells in real time during an operation period of the vehicle to obtain a first voltage dataset for the each cell (S101); characterised by : performing a first filtering process on the first voltage dataset to retain voltage data corresponding to operating currents less than a first threshold, such that a filtered second voltage dataset for the each cell is obtained (S102); calculating an energy score for the each cell based on the second voltage dataset (S103); and calculating a first consistency score for the power battery based on the calculated energy score for the each cell (S104).
  2. The method of claim 1, wherein the obtaining a filtered second voltage dataset for the each cell further comprises: performing a second filtering process on the first voltage dataset to retain voltage data corresponding to a specific section of state of charge.
  3. The method of claim 1, wherein the calculating an energy score for the each cell comprises: transforming the second voltage dataset into a frequency domain dataset with amplitude; and calculating the energy score for the each cell based on corresponding amplitudes of low-frequency components in the frequency domain dataset.
  4. The method of any one of claims 1 to 3, wherein the calculating a first consistency score for the power battery comprises: performing a normalizing process on the calculated energy score for the each cell; determining a limit value according to statistical data of historical energy score, the limit value including at least one of an upper limit value and a lower limit value of the energy score; determining an energy score exceeding the limit value by a second threshold as an outlier; and calculating an Euclidean distance between the outlier and the exceeded limit value as the first consistency score.
  5. The method of claim 4, wherein the calculating a first consistency score for the power battery further comprises: performing, using a principal component analysis method, a data dimension reduction process on the Euclidean distance of the outlier and an additional parameter during the operation period, and determining a value obtained by the data dimension reduction as the first consistency score; or calculating, using a machine learning-based model, the first consistency score for the power battery based on the Euclidean distance of the outlier and the additional parameter; wherein the additional parameter is selected from a group consisting of: state of charge of the power battery, usage time of the power battery, temperature of the power battery, resistance of the power battery, and current mileage of the vehicle.
  6. A method for visualization of consistency for power battery, comprising: providing a first visualized representation of the energy score for the each cell as a function of a specific variable, based on the energy score calculated according to the method of any one of claims 1 to 5; wherein the specific variable is a variable related to mileage of the vehicle or usage time of the power battery.
  7. The method for visualization of claim 6, further comprising: displaying a first decision line in the first visualized representation, wherein the first decision line is determined according to statistical data of historical energy score; and indicating a cell corresponding to a function exceeding the first decision line by a third threshold as an abnormal cell.
  8. A method for estimating vehicle level-based consistency for power battery, comprising: calculating, for each vehicle of a plurality of vehicles using the same power batteries, the first consistency score for the power battery of the each vehicle, respectively, according to the method of any one of claims 1 to 5; and calculating a vehicle level-based second consistency score for power battery based on the first consistency score for the power battery of the each vehicle.
  9. A method for visualization of vehicle level-based consistency for power battery, comprising: providing a second visualized representation of the first consistency score for the power battery of the each vehicle as a function of a specific variable, based on the first consistency score for the power battery of the each vehicle calculated according to the method of claim 8; wherein the specific variable is a variable related to mileage of the each vehicle or usage time of the power battery of the each vehicle.
  10. The method of claim 9, further comprising: displaying a second decision line in the second visualized representation, wherein the second decision line is determined according to statistical data of historical second consistency score; and indicating a vehicle corresponding to a function exceeding the second decision line by a fourth threshold as an abnormal vehicle.
  11. An apparatus (600) for estimating consistency for power battery which is composed of a plurality of cells and is configured to provide energy for a vehicle, the apparatus comprising: a processor (610); and a memory (620) having stored computer program instructions therein, wherein the computer program instructions, when executed by the processor, cause the processor to perform a method of any one of claims 1-5.
  12. The apparatus of claim 11, further comprising a device (630) for visualizing the consistency for power battery, the device being configured to: provide a first visualized representation of the energy score for the each cell as a function of a specific variable based on the calculated energy score, wherein the specific variable is a variable related to mileage of the vehicle or usage time of the power battery; display a first decision line in the first visualized representation, wherein the first decision line is determined according to statistical data of historical energy score; and indicate a cell corresponding to a function exceeding the first decision line by a third threshold as an abnormal cell.
  13. An apparatus (600) for estimating vehicle level-based consistency for power battery, the apparatus comprising: a processor (610); and a memory (620) having stored computer program instructions therein, wherein the computer program instructions, when executed by the processor, cause the processor to: calculate, for each vehicle of a plurality of vehicles using the same power batteries, the first consistency score for the power battery of the each vehicle, respectively, according to the method of any one of claims 1-5; and calculate a vehicle level-based second consistency score for power battery based on the first consistency score for the power battery of the each vehicle.
  14. The apparatus of claim 13, further comprising a device for visualizing the consistency for power battery, wherein the device for visualizing the consistency for power battery is configured to: provide a second visualized representation of the first consistency score for the power battery of the each vehicle as a function of a specific variable based on the calculated first consistency score for the power battery of the each vehicle, wherein the specific variable is a variable related to mileage of the each vehicle or usage time of the power battery of the each vehicle; display a second decision line in the second visualized representation, wherein the second decision line is determined according to statistical data of historical second consistency score; and indicate a vehicle corresponding to a function exceeding the second decision line by a fourth threshold as an abnormal vehicle.
  15. A computer-readable storage medium having stored computer program instructions thereon, wherein the computer program instructions, when executed by a processor, implement the method of any one of claims 1 to 10.

Description

TECHNICAL FIELD The present invention relates to the field of electric automobiles, and more particularly, to a method and an apparatus for estimation and visualization of consistency for power battery. BACKGROUND With the increasingly serious global environmental and energy problems, new energy automobiles have attracted a wide attention because of their advantages such as energy saving, high efficiency, low carbon and environmental friendliness. In recent years, a rapid rise of the industry of electric automobiles such as pure electric automobiles and hybrid electric automobiles has become an inevitable trend of the development of automobile industry. However, there are still some problems to be urgently solved in the field of electric automobile application technology. The document CN 102 540 098 A discloses a data collection method for a battery pack. The method involves obtaining datasets for use in the determination of a battery operating in a vehicle. To this end the respective voltage of each cell is measured and the ensuing voltage dataset is digitally filtered to suppress noise. Power battery, which is one of the core components of electric automobiles, takes responsibility for storing and releasing electric energy for providing a vehicle with energy for driving and other vehicle applications, that is, power battery is used as a power supply for the vehicle. Taking the existing Li-ion battery as an example, the power battery is usually a battery pack composed of a plurality of monomer cells in series and/or in parallel. However, since the monomer cells can be affected during the production by various factors such as technological or environmental factors, there are inevitably differences among respective cells in terms of such as internal resistance, capacity, State of Charge (SOC) and the like, and such differences can be further aggravated during the use of battery, resulting in that the performances among the cells fail to be completely consistent, that is, inconsistency for power battery. Disadvantageously, such inconsistency can lead to problems such as reduction in vehicle's endurance mileage, damage to battery pack health and the like, and eventually incur decline in reliability of power battery and even premature failure. Therefore, in order to guarantee the delivery of a high-quality vehicle to the user, it is necessary to accurately estimate and evaluate the consistency for power battery in the early testing stage for vehicles. In view of the above, there is a need for an improved estimation method and visualization method for consistency for power battery, and an apparatus for implementing the above method. SUMMARY According to one aspect of the present disclosure, there is provided a method for estimation of consistency for power battery, including: detecting operating voltages for each cell of a plurality of cells in real time during an operation period of a vehicle to obtain a first voltage dataset for the each cell; performing a first filtering process on the first voltage dataset to retain voltage data corresponding to operating currents less than a first threshold, such that a filtered second voltage dataset for the each cell is obtained; calculating an energy score for the each cell based on the second voltage dataset; and calculating a first consistency score for the power battery based on the calculated energy score for the each cell. According to an embodiment of the present disclosure, the obtaining a filtered second voltage dataset for the each cell further includes: performing a second filtering process on the first voltage dataset to retain voltage data corresponding to a specific section of state of charge (SOC). According to an embodiment of the present disclosure, the calculating an energy score for the each cell includes: transforming the second voltage dataset into a frequency domain dataset with amplitude; and calculating the energy score for the each cell based on corresponding amplitudes of low-frequency components in the frequency domain dataset. According to an embodiment of the present disclosure, the calculating a first consistency score for the power battery includes: performing a normalizing process on the calculated energy score for the each cell; determining a limit value according to statistical data of historical energy score, the limit value including at least one of an upper limit value and a lower limit value of the energy score; determining an energy score exceeding the limit value by a second threshold as an outlier; and calculating an Euclidean distance between the outlier and the exceeded limit value as the first consistency score, in which the calculating the first consistency score for the power battery further includes: performing, using a principal component analysis (PCA) method, a data dimension reduction process on the Euclidean distance of the outlier and an additional parameter during the operation period, and determining a value obtained