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KR-20260066495-A - APPARATUS FOR DIAGNOSING STATUS OF BATTERY AND METHOD THEREOF

KR20260066495AKR 20260066495 AKR20260066495 AKR 20260066495AKR-20260066495-A

Abstract

The present invention relates to a battery condition diagnosis device and method, and aims to provide a battery condition diagnosis device and method capable of diagnosing not only the battery condition but also the condition of each cell constituting the battery with high accuracy by monitoring the charging current of the battery to detect a current interval that maintains a preset current change value, determining the minimum voltage and maximum voltage of said current interval, detecting the time it takes for each cell voltage of the battery to reach the maximum voltage from said minimum voltage within said current interval, and diagnosing the battery condition based on the time corresponding to said cell. To this end, the present invention may include a current sensor for detecting a charging current of a battery; a voltage sensor for detecting a voltage of the battery; and a control unit that monitors the charging current of the battery to detect a current interval that maintains a preset current change value, determines a minimum voltage and a maximum voltage as a voltage range of the current interval, detects the time for each cell voltage of the battery to reach the maximum voltage from the minimum voltage within the current interval, and diagnoses the state of the battery based on the time corresponding to each cell.

Inventors

  • 백요한

Assignees

  • 현대자동차주식회사
  • 기아 주식회사

Dates

Publication Date
20260512
Application Date
20241104

Claims (18)

  1. A current sensor that detects the charging current of a battery; A voltage sensor for detecting the voltage of the above battery; and A control unit that monitors the charging current of the battery to detect a current interval that maintains a preset current change value, determines a minimum voltage and a maximum voltage as a voltage range of the current interval, detects the time for each cell voltage of the battery to reach the maximum voltage from the minimum voltage within the current interval, and diagnoses the state of the battery based on the time corresponding to each cell. A battery condition diagnostic device including
  2. In Article 1, The above control unit is, A battery condition diagnosis device characterized by detecting a maximum voltage and a minimum voltage for each cell in the above current range, determining the maximum value among the minimum voltages of each cell as the minimum voltage of the above current range, and determining the minimum value among the maximum voltages of each cell as the maximum voltage of the above current range.
  3. In Article 1, The above control unit is, A battery condition diagnosis device characterized by determining the standard deviation of times corresponding to each of the above cells and diagnosing the condition of the battery based on the standard deviation.
  4. In Article 1, The above control unit is, A battery condition diagnosis device characterized by detecting at least one of the above current intervals, determining a minimum voltage and a maximum voltage for each current interval, detecting the time for each cell voltage to reach from the minimum voltage to the maximum voltage for each current interval, and diagnosing the condition of the battery based on the time corresponding to each cell for each current interval.
  5. In Article 4, The above control unit is, A battery condition diagnosis device characterized by determining the standard deviation of times corresponding to each cell for each of the above current intervals and diagnosing the condition of the battery based on the standard deviation for each of the above current intervals.
  6. In Article 1, The above control unit is, A battery condition diagnosis device characterized by dividing the above voltage range into a plurality of voltage intervals, detecting the time for each cell voltage to reach the maximum voltage from the minimum voltage for each voltage interval, and diagnosing the condition of the battery based on the time corresponding to each cell for each voltage interval.
  7. In Article 6, The above control unit is, A battery condition diagnosis device characterized by determining the standard deviation of times corresponding to each cell for each voltage interval and diagnosing the condition of the battery based on the standard deviation for each voltage interval.
  8. In Article 1, The above control unit is, A battery condition diagnostic device characterized by monitoring the charging current of the battery in all sections except the state transition section between CCV (Closed Circuit Voltage) and OCV (Open Circuit Voltage).
  9. In Article 1, The above control unit is, A battery condition diagnosis device characterized by detecting a constant current section where the current change value is 0 (zero) as the current section.
  10. A step in which a control unit monitors the battery charging current and detects a current interval that maintains a preset current change value; A step in which the control unit determines a minimum voltage and a maximum voltage as the voltage range of the current section; The control unit detects the time during which each cell voltage of the battery reaches the maximum voltage from the minimum voltage within the current interval; and The control unit diagnoses the state of the battery based on the time corresponding to each cell. A method for diagnosing the condition of a battery including
  11. In Article 10, The step of determining the above minimum voltage and maximum voltage is, A step of detecting the maximum voltage and minimum voltage for each cell in the above current range; A step of determining the maximum value among the minimum voltages of each of the above cells as the minimum voltage of the above current range; and Step of determining the minimum value among the maximum voltages of each cell as the maximum voltage of the current range A method for diagnosing the condition of a battery including
  12. In Article 10, The step of diagnosing the condition of the battery above is, A step of determining the standard deviation of the times corresponding to each of the above cells; and Step of diagnosing the condition of the battery based on the above standard deviation A method for diagnosing the condition of a battery including
  13. In Article 10, The step of diagnosing the condition of the battery above is, When at least one of the above current intervals is detected, the step of determining the state of the battery based on the time corresponding to each cell for each current interval A method for diagnosing the condition of a battery including
  14. In Article 13, The step of determining the state of the above battery is, A step of determining the standard deviation of times corresponding to each cell for each of the above current intervals; and A step of diagnosing the condition of the battery based on the standard deviation for each of the above current intervals. A method for diagnosing the condition of a battery including
  15. In Article 10, The step of diagnosing the condition of the battery above is, When the above voltage range is divided into multiple voltage intervals, the step of determining the state of the battery based on the time corresponding to each cell for each voltage interval. A method for diagnosing the condition of a battery including
  16. In Article 15, The step of determining the state of the above battery is, A step of determining the standard deviation of the times corresponding to each cell for each of the above voltage intervals; and A step of diagnosing the condition of the battery based on the standard deviation for each voltage range above. A method for diagnosing the condition of a battery including
  17. In Article 10, The step of detecting the above current interval is, A step of monitoring the charging current of the battery in all sections except the state transition section between CCV (Closed Circuit Voltage) and OCV (Open Circuit Voltage). A method for diagnosing the condition of a battery including
  18. In Article 10, The step of detecting the above current interval is, A step of detecting a constant current section where the above current change value is 0 (zero). A method for diagnosing the condition of a battery including

Description

Apparatus for Diagnosing Status of Battery and Method Thereof The present invention relates to a technology for diagnosing the condition of a battery equipped in an electric vehicle with high accuracy. Generally, an electric vehicle is a vehicle that is driven by electric energy and is equipped with a battery composed of multiple battery cells that store electric energy. These battery cells convert chemical energy into electrical energy to supply electric energy (discharge) or convert electrical energy supplied from the outside into chemical energy to store it (charge). Since these electric vehicles are driven by electrical energy stored in batteries, their performance is determined by the battery's performance. Therefore, to improve the performance of electric vehicles, the batteries must be managed to maximize their capabilities. Recently, as there is a trend to use high-performance battery cells to enhance automotive power sources and to gradually increase the number of battery cells, the need for battery management is becoming increasingly important. This battery management is generally performed by a Battery Management System (BMS). This battery management system measures cell status information, such as voltage, current, and temperature of battery cells, from a battery module equipped in an electric vehicle, manages the charging and discharging of each battery cell using the cell status information and option values for controlling the battery cells, and performs cell balancing to maintain balance among multiple battery cells. This cell balancing is one of the control operations of a battery management system that equalizes the voltage or charge of battery cells. Even if each battery cell in a battery module is manufactured under the same manufacturing conditions and in the same environment, there may be differences in electrical characteristics, and there may also be differences in electrical characteristics while they are installed and operating in an electric vehicle. Due to such differences in electrical characteristics, even when battery cells are charged and discharged with the same current, voltage imbalance or residual charge imbalance occurs between interconnected battery cells, and voltage imbalance or residual charge imbalance between battery cells can cause the available voltage range of the battery cells to decrease or the charging and discharging cycle to become shorter. Recently, fires have been occurring frequently in electric vehicles while charging their batteries. As this is caused by abnormal battery conditions, technology capable of accurately diagnosing the condition of batteries equipped in electric vehicles is required to prevent such fires. A conventional technology for diagnosing the condition of a battery monitors the voltage change of the battery in a first transition section transitioning from a load state (Closed Circuit Voltage, CCV) to a no-load state (Open Circuit Voltage, OCV) and a second transition section transitioning from a no-load state to a load state, and diagnoses the condition of the battery based on the monitoring results. These conventional technologies cannot adequately monitor battery voltage changes because they are required to monitor changes only during the first and second transition periods, which are very short in time. Consequently, there is a problem in that the battery condition cannot be diagnosed with high accuracy. The matters described in this background technology section are written to enhance understanding of the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. FIG. 1 is a configuration diagram of a battery condition diagnostic device according to an embodiment of the present invention, FIG. 2 is an example of a section in which a control unit equipped in a battery state diagnosis device according to an embodiment of the present invention monitors the charging current of a battery. FIG. 3 is an example of a current range detected by a control unit provided in a battery state diagnosis device according to an embodiment of the present invention. FIG. 4a is an example diagram showing the voltage of each cell constituting the battery within the current interval (C1). FIG. 4b is an example diagram showing the voltage of each cell constituting the battery within the current interval (C2). FIG. 4c is an example diagram showing the voltage of each cell constituting the battery within the current interval (C3). FIG. 4d is an example diagram showing the voltage of each cell constituting the battery within the current interval (C4). FIG. 4e is an example diagram showing the voltage of each cell constituting the battery within the current interval (C5). FIG. 4f is an example diagram showing the voltage of each cell constituting the battery within the current interval (C6). FIG. 5 is an exemplary diagram showing the process of a control unit equipped