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KR-102961048-B1 - Battery monitoring device, battery management system

KR102961048B1KR 102961048 B1KR102961048 B1KR 102961048B1KR-102961048-B1

Abstract

The battery monitoring device monitors the battery. The battery monitoring device is equipped with a degradation detection unit (37, 38) that detects a physical quantity that is more correlated with the degradation of the battery capacity than the voltage and current of the battery, and a volume ratio estimation unit (542) that estimates the volume ratio of the battery based on the physical quantity.

Inventors

  • 시미즈 사토루
  • 마와타리 가즈아키
  • 오노 가즈유키
  • 가와바타 구미코
  • 마츠이 히로시게

Assignees

  • 가부시키가이샤 덴소

Dates

Publication Date
20260508
Application Date
20221212
Priority Date
20211224

Claims (7)

  1. It is a battery monitoring device that monitors batteries, and A degradation detection unit (37, 38) that detects a physical quantity that is more correlated with the capacity degradation of the battery than the voltage and current of the battery, and A volume ratio estimation unit (542) for estimating the volume ratio of the battery based on the above physical quantity is provided, The above battery is a lithium-ion battery, and The above degradation detection unit detects at least one of the amount of lithium precipitation inside the lithium-ion battery and the thickness of the film formed at the interface between the negative electrode and the electrolyte of the lithium-ion battery as the physical quantity, and The above-mentioned degradation detection unit includes a short circuit (371) that discharges by temporarily short-circuiting both ends of the lithium-ion battery, and calculates at least one of the lithium deposition amount and the thickness of the film based on a change in at least one of the current and voltage flowing through the short circuit when the two ends of the lithium-ion battery are short-circuited in the short circuit.
  2. In paragraph 1, The above lithium-ion battery is equipped with a temperature sensor (31) for detecting the battery temperature, and The above degradation detection unit is a battery monitoring device that calculates a correction value, which corrects at least one of the lithium precipitation amount and the thickness of the film to the battery temperature, as the physical quantity.
  3. A battery management system comprising a battery monitoring device described in paragraph 1 or 2, and A battery management system that determines whether secondary use of the battery is possible based on the volume ratio estimated by the volume ratio estimation unit.
  4. A battery management system comprising a battery monitoring device described in paragraph 1 or 2, and A battery management system that determines whether there is an abnormality in the battery based on the volume ratio estimated by the volume ratio estimation unit, and sets the remaining value of the battery if there is an abnormality in the battery.
  5. A battery management system comprising a battery monitoring device described in paragraph 1 or 2, and A battery management system that determines whether the volume rate estimated by the volume rate estimation unit is within the allowable range of the volume rate displayed in the specification data of the battery, and outputs the result of this determination to the outside.
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Description

Battery monitoring device, battery management system This application is based on Japanese Patent Application No. 2021-211049 filed on December 24, 2021, the contents of which are incorporated by reference. The present disclosure relates to a battery monitoring device and a battery management system. Patent Document 1 discloses a method for calculating the full charge amount of a battery. In this calculation method, first, the change in charge/discharge amount between a first time point and a second time point is calculated by integrating the current value of the output current of the battery over time. Then, the OCV at the first time point and the second time point is measured, and the SOC at the first time point and the second time point is calculated using an SOC-OCV curve, and the change amount ΔSOC is calculated as the deviation of the SOC at each time point. Subsequently, the full charge amount of the battery is calculated by dividing the change in charge/discharge amount by the change in SOC ΔSOC. In addition, the volume ratio SOH of the battery is obtained by dividing the full charge amount of the battery by the initial value of the full charge amount. The above method for calculating SOC and SOH is not practical because it lacks real-time capability, as it cannot calculate the charge or discharge amount of the battery unless a certain amount of charge or discharge occurs, in order to avoid the influence of errors in current sensors or voltage sensors. The present disclosure aims to provide a battery monitoring device and a battery management system capable of determining the battery status in a practical manner. According to one aspect of the present disclosure, The battery monitoring device is, A degradation detection unit that detects physical quantities that are more correlated with battery capacity degradation than the voltage and current of the battery, and A volume ratio estimation unit is provided to estimate the volume ratio of a battery based on physical quantities. According to this, if the capacity ratio is estimated using a physical quantity highly correlated with the degradation of the battery capacity, the need to avoid the influence of errors is reduced compared to the conventional method of calculating the capacity ratio from the battery current and voltage, thereby allowing the capacity ratio to be estimated in a short time. Therefore, according to the battery monitoring device of the present invention, it becomes possible to determine the state of the battery in a practical manner. In addition, the parenthetical reference numerals assigned to each component, etc. represent examples of correspondence relationships between the component, etc. and specific components, etc. described in the embodiments described below. FIG. 1 is a schematic diagram illustrating a battery pack to which a battery monitoring device according to an embodiment is applied. Figure 2 is an explanatory diagram for describing a lithium-ion battery. Figure 3 is a schematic diagram of a battery management system including a battery monitoring device. Figure 4 is an explanatory diagram for explaining a battery monitoring device. Figure 5 is an explanatory diagram for explaining the precipitation amount calculation unit included in the battery monitoring device. Figure 6 is an explanatory diagram for explaining the method of calculating the amount of lithium precipitate. Figure 7 is an explanatory diagram for explaining the method of calculating parasitic resistance values. Figure 8 is an explanatory diagram to explain the flow of calculating the lithium precipitation amount. Figure 9 is an explanatory diagram for explaining the diagnosis of the precipitation amount calculation unit by the diagnosis unit. Figure 10 is an explanatory diagram for explaining the method of calculating the volumetric SOH of a battery. Figure 11 is a timing chart showing the change in output of various sensors before and after the occurrence of an abnormal heat generation phenomenon. Figure 12 is an explanation for illustrating the flow of control processing performed by the battery monitoring device. Figure 13 is a schematic diagram of a battery management system including a battery monitoring device. One embodiment of the present disclosure will be described with reference to FIGS. 1 to 13. In this embodiment, an example in which the battery monitoring device (20) and the battery monitoring method of the present disclosure are applied to a battery management unit (hereinafter also referred to as BMU) of a vehicle equipped with a battery pack (1) which is a high-voltage battery will be described. The BMU is equipped with a battery pack (1) as illustrated in FIG. 1. The battery pack (1) is equipped with a sealed container (11) that forms the outer shell, and a plurality of battery modules BM, a battery monitoring device (20), and a battery ECU (100) are housed inside the sealed container (11). The sealed container (11) is provided with a