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EP-4742494-A1 - BATTERY MANAGEMENT SYSTEM AND BATTERY MANAGEMENT METHOD

EP4742494A1EP 4742494 A1EP4742494 A1EP 4742494A1EP-4742494-A1

Abstract

A battery management system (300) includes an impedance measurement unit (310) configured to measure at least one of an impedance of a battery (400) for each charging cycle or an impedance of the battery (400) for each discharging cycle, and a battery control unit (330) configured to perform at least one of calculating an amount of change in a charging impedance by comparing an impedance of a current charging cycle with an impedance of a previous charging cycle, and setting a next discharging completion voltage of the battery (400) based on the amount of change in the charging impedance, or calculating an amount of change in a discharging impedance by comparing an impedance of a current discharging cycle with an impedance of a previous discharging cycle, and setting a next charging completion voltage of the battery (400) based on the amount of change in the discharging impedance.

Inventors

  • SEOL, Junha

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20251104

Claims (15)

  1. A battery management system (300) comprising: an impedance measurement unit (310) configured to measure at least one of an impedance of a battery (400) for each charging cycle or an impedance of the battery (400) for each discharging cycle; and a battery control unit (330) configured to perform at least one of calculating an amount of change in a charging impedance by comparing an impedance of a current charging cycle with an impedance of a previous charging cycle, and setting a next discharging completion voltage of the battery (400) based on the amount of change in the charging impedance, or calculating an amount of change in a discharging impedance by comparing an impedance of a current discharging cycle with an impedance of a previous discharging cycle, and setting a next charging completion voltage of the battery (400) based on the amount of change in the discharging impedance.
  2. The battery management system (300) as claimed in claim 1, wherein the impedance measurement unit (310) is configured to measure impedances in preset frequency units by electrochemical impedance spectroscopy (EIS).
  3. The battery management system (300) as claimed in claim 2, wherein the battery control unit (330) is configured to: compare a magnitude of an impedance for each preset frequency of an impedance for each current charging cycle with a magnitude of an impedance for each impedance for each preset frequency of an impedance for each previous charging cycle; calculate an average amount of change in a charging impedance of an amount of change of an impedance for said each preset frequency; and set the next discharging completion voltage of the battery (400) based on the average amount of change in the charging impedance.
  4. The battery management system (300) as claimed in claim 3, wherein the battery control unit (330) is configured to decrease the next discharging completion voltage by a preset rate from a current discharging completion voltage in inverse proportion to the average amount of change in the charging impedance if the average amount of change in the charging impedance has increased.
  5. The battery management system (300) as claimed in claim 3 or claim 4, wherein the battery control unit (330) is configured to increase the next discharging completion voltage by a preset rate from a current discharging completion voltage in inverse proportion to the average amount of change in the charging impedance if the average amount of change in the charging impedance has decreased.
  6. The battery management system (300) as claimed in any of claims 2 to 5, wherein the battery control unit (330) is configured to: compare a magnitude of an impedance for each preset frequency of an impedance for each current discharging cycle with a magnitude of an impedance for each impedance for each preset frequency of an impedance for each previous discharging cycle; calculate an average amount of change in a discharging impedance of an amount of change of an impedance for said each preset frequency; and set the next charging completion voltage of the battery (400) based on the average amount of change in the discharging impedance.
  7. The battery management system (300) as claimed in claim 6, wherein the battery control unit (330)is configured to increase the next charging completion voltage by a preset rate from a current discharging completion voltage in proportion to the average amount of change in the discharging impedance if the average amount of change in the discharging impedance has increased.
  8. The battery management system (300) as claimed in claim 6 or claim 7, wherein the battery control unit (330) is configured to decrease the next charging completion voltage by a preset rate from a current discharging completion voltage in proportion to the average amount of change in the discharging impedance if the average amount of change in the discharging impedance has decreased.
  9. The battery management system (300) as claimed in any preceding claim, wherein the battery control unit (330) is configured to: set a first charging impedance of the battery (400) measured when the battery (400) is first charged after being shipped as a basic charging impedance; set a voltage measured after the first charging is completed as a basic charging completion voltage; and set the next charging completion voltage to be lower than the basic charging completion voltage.
  10. The battery management system (300) as claimed in any preceding claim, wherein the battery control unit (330) is configured to: set a first discharging impedance of the battery (400) measured when the battery (400) is first discharged after being initially charged as a basic discharging impedance; set a voltage measured after the first discharging is completed as a basic discharging completion voltage; and set the next discharging completion voltage to be higher than the basic discharging completion voltage.
  11. A method of managing a battery (400), comprising: measuring at least one of an impedance of a battery (400) for each charging cycle or an impedance of the battery (400) for each discharging cycle, wherein the measuring the impedance of the battery (400) comprises measuring impedances in preset frequency units by electrochemical impedance spectroscopy (EIS); performing at least one of calculating an amount of change in a charging impedance by comparing an impedance of a current charging cycle with an impedance of a previous charging cycle, and setting a next discharging completion voltage of the battery (400) based on the amount of change in the charging impedance, or calculating an amount of change in a discharging impedance by comparing an impedance of a current discharging cycle with an impedance of a previous discharging cycle, and setting a next charging completion voltage of the battery (400) based on the amount of change in the discharging impedance; and terminating charging of the battery (400) when the battery (400) is charged or reaches the next charging completion voltage, or terminating discharging of the battery (400) when the battery (400) is discharged or reaches the next discharging completion voltage.
  12. The method as claimed in claim 11, wherein the setting the next discharging completion voltage comprises: comparing a magnitude of an impedance for each preset frequency of an impedance for each current charging cycle with a magnitude of an impedance for each impedance for each preset frequency of an impedance for each previous charging cycle; calculating an average amount of change in a charging impedance of an amount of change of an impedance for said each preset frequency; and setting the next discharging completion voltage based on the average amount of change in the charging impedance.
  13. The method as claimed in claim 12, wherein the setting the next discharging completion voltage comprises: decreasing the next discharging completion voltage if the average amount of change in the charging impedance has increased; and increasing the next discharging completion voltage if the average amount of change in the charging impedance has decreased.
  14. The method as claimed in claim 11, wherein the setting the next charging completion voltage comprises: comparing a magnitude of an impedance for each preset frequency of an impedance for each current discharging cycle with a magnitude of an impedance for each impedance for each preset frequency of an impedance for each previous discharging cycle; calculating an average amount of change in a discharging impedance of an amount of change of an impedance for said each preset frequency; and setting the next charging completion voltage of the battery (400) based on the average amount of change in the discharging impedance.
  15. The method as claimed in claim 14, wherein the setting the next charging completion voltage comprises: increasing the next charging completion voltage if the average amount of change in the discharging impedance has increased; and decreasing the next charging completion voltage if the average amount of change in the discharging impedance has decreased.

Description

FIELD Aspects of embodiments of the present disclosure relate to a battery management system and a battery management method. BACKGROUND Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable, small electronic devices, such as smart phones, feature phones, notebook computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and for storing power (e.g., home and/or utility scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case accommodating the same, and electrode terminals connected to the electrode assembly. Energy storage systems (ESS) can connect renewable energy sources such as wind, solar power, or the like, whose power generation output cannot be controlled, to an existing power grid and charge or discharge energy according to the power consumption pattern. In particular, a battery energy storage system using secondary batteries can not only be used to stabilize system voltage and frequency, but also store surplus energy in conjunction with a renewable energy generation system whose power generation output is not consistent, such as wind, solar power, or the like, and discharge the energy stored in the batteries to supply energy to loads. In an energy storage system, efficient management of the batteries is one of the important factors. By managing various matters such as charging, discharging, and cell balancing of the batteries, the service life of the batteries can be extended, and power can be stably supplied to loads. To this end, the energy storage system may include a battery management system (BMS). There is a fire risk due to deterioration if the batteries are overcharged or overdischarged. The battery management system needs to manage the batteries to ensure that the batteries are not overcharged or overdischarged. The herein information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute related (or prior) art. SUMMARY Embodiments of the present disclosure provide a battery management system and a battery management method to solve the herein problem. However, the technical problem to be solved by the present disclosure is not limited to the herein problem, and other problems not mentioned herein, and aspects and features of the present disclosure that would address such problems, will be clearly understood by those skilled in the art from the description of the present disclosure herein. According to embodiments of the present disclosure to solve the herein technical problem, a battery management system may include an impedance measurement unit configured to measure at least one of an impedance of a battery for each charging cycle or an impedance of the battery for each discharging cycle, and a battery control unit configured to perform at least one of calculating an amount of change in a charging impedance by comparing an impedance of a current charging cycle with an impedance of a previous charging cycle, and setting a next discharging completion voltage of the battery based on the amount of change in the charging impedance, or calculating an amount of change in a discharging impedance by comparing an impedance of a current discharging cycle with an impedance of a previous discharging cycle, and setting a next charging completion voltage of the battery based on the amount of change in the discharging impedance. According to one or more embodiments, the impedance measurement unit may measure impedances in preset frequency units by electrochemical impedance spectroscopy (EIS). According to one or more embodiments, the battery control unit may compare a magnitude of an impedance for each preset frequency of an impedance for each current charging cycle with a magnitude of an impedance for each impedance for each preset frequency of an impedance for each previous charging cycle, calculate an average amount of change in a charging impedance of an amount of change of an impedance for said each preset frequency, and set the next discharging completion voltage based on the average amount of change in the charging impedance. According to one or more embodiments, the battery control unit may decrease the next discharging completion voltage if the average amount of change in the charging impedance has increased. According to one or more embodiments, the battery control unit may decrease the next discharging completion voltage by a preset rate from a current discharging completion voltage in inverse proportion to the average amount of change in the charging impedance. According to one or more embod