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EP-4741854-A1 - BATTERY DIAGNOSIS DEVICE AND BATTERY DIAGNOSIS METHOD

EP4741854A1EP 4741854 A1EP4741854 A1EP 4741854A1EP-4741854-A1

Abstract

A battery diagnosis apparatus disclosed herein includes a sensor unit configured to obtain battery cell information for each of at least one battery cells and a control unit configured to determine a state of health (SOH) of each of the at least one battery cells based on the battery cell information and determine whether a defect occurs in the at least one battery cells based on an average and a standard deviation of the SOHs.

Inventors

  • BYUN, Ha Eun

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260513
Application Date
20240812

Claims (14)

  1. A battery diagnosis apparatus comprising: a sensor unit configured to obtain battery cell information for each of at least one battery cells; and a control unit configured to determine a state of health (SOH) of each of the at least one battery cells based on the battery cell information and determine whether a defect occurs in the at least one battery cells based on an average and a standard deviation of the SOHs.
  2. The battery diagnosis apparatus of claim 1, wherein the control unit is further configured to determine, as a reference SOH, a value obtained by excluding the standard deviation from the average of the SOHs and determine that a defect occurs in the battery cell based on that the SOHs of the at least one battery cells are less than the reference SOH.
  3. The battery diagnosis apparatus of claim 1, wherein the average of the SOHs comprises an average of preset top SOHs among the SOHs of the at least one battery cells.
  4. The battery diagnosis apparatus of claim 1, wherein the standard deviation is determined as a value greater between the standard deviation calculated based on the SOH of each of the at least one battery cells and a preset reference standard deviation.
  5. The battery diagnosis apparatus of claim 1, wherein the control unit is further configured to determine an open circuit voltage (OCV) of the at least one battery cells and determine that a defect occurs in the battery cell based on that the OCV is greater than a reference OCV obtained by excluding an OCV deviation from an average OCV.
  6. The battery diagnosis apparatus of claim 1, wherein the control unit is further configured to determine the SOH of each of the at least one battery cell by applying a current detected by the sensor unit to a current integration method.
  7. The battery diagnosis apparatus of claim 1, wherein the control unit is further configured to transmit the battery cell information comprising the defect occurring to an external device, based on the determining of that the defect occurs in the at least one battery cells.
  8. A battery diagnosis method comprising: obtaining battery cell information for each of at least one battery cells; determining a state of health (SOH) of each of the at least one battery cells based on the battery cell information; and determining whether a defect occurs in the at least one battery cells based on an average and a standard deviation of the SOHs.
  9. The battery diagnosis method of claim 8, wherein the determining of whether the defect occurs in the at least one battery cells comprises determining, as a reference SOH, a value obtained by excluding the standard deviation from the average of the SOHs and determining that a defect occurs in the battery cell based on that the SOHs of the at least one battery cells are less than the reference SOH.
  10. The battery diagnosis method of claim 8, wherein the average of the SOHs comprises an average of preset top SOHs among the SOHs of the at least one battery cells.
  11. The battery diagnosis method of claim 8, wherein the standard deviation is determined as a value greater between the standard deviation calculated based on the SOH of each of the at least one battery cells and a preset reference standard deviation.
  12. The battery diagnosis method of claim 8, wherein the determining of whether the defect occurs in the at least one battery cells comprises determining an open circuit voltage (OCV) of the at least one battery cells and determining that a defect occurs in the battery cell based on that the OCV is greater than a reference OCV obtained by excluding an OCV deviation from an average OCV.
  13. The battery diagnosis method of claim 8, wherein the determining of the SOH of each of the at least one battery cells comprises determine the SOH of each of the at least one battery cell by applying a current detected by a sensor unit to a current integration method.
  14. The battery diagnosis method of claim 8, further comprising transmitting the battery cell information comprising the defect occurring to an external device, based on the determining of that the defect occurs in the at least one battery cells.

Description

TECHNICAL FIELD CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0108629 filed in the Korean Intellectual Property Office on August 18, 2023, the entire content of which is incorporated herein by reference. TECHNICAL FIELD Embodiments disclosed herein relate to a battery diagnosis apparatus and a battery diagnosis method for diagnosing a state of a battery. BACKGROUND ART Recently, research and development of secondary batteries have been actively performed. Herein, the secondary batteries, which are chargeable/dischargeable batteries, may include all of conventional nickel (Ni)/cadmium (Cd) batteries, Ni/metal hydride (MH) batteries, etc., and recent lithium-ion batteries. Among the secondary batteries, a lithium-ion battery has a much higher energy density than those of the conventional Ni/Cd batteries, Ni/MH batteries, etc. Moreover, the lithium-ion battery may be manufactured to be small and lightweight, such that the lithium-ion battery has been used as a power source of mobile devices. In addition, the lithium-ion battery is attracting attention as a next-generation energy storage medium as a usage range thereof is expanded to a power source of electric vehicles. As the occurrence of defective battery cells, such as tab disconnection or lithium precipitation, in the battery may cause safety issues during battery use, research is being conducted on a defective battery cell detection algorithm. Conventionally, as a defective battery cell has a smaller capacity than a normal battery cells, a diagnosis target battery cell is diagnosed as a defective battery cell when having a state of health (SOH) less than an SOH median value in a battery module by a predetermined level. However, this method is applicable to a case when a battery system has a function of estimating an SOH, and thus is difficult to apply to a battery system having no SOH estimation algorithm, and the algorithm depends on the accuracy of SOH estimation. DISCLOSURE TECHNICAL PROBLEM According to an embodiment disclosed herein, there are provided a battery diagnosis apparatus and a battery diagnosis method based on a battery capacity deviation without relying on whether a battery has a state of health (SOH) estimation algorithm or not. Technical problems of the embodiments disclosed herein are not limited to the above-described technical problems, and other unmentioned technical problems would be clearly understood by one of ordinary skill in the art from the following description. TECHNICAL SOLUTION A battery diagnosis apparatus according to an embodiment includes a sensor unit configured to obtain battery cell information for each of at least one battery cells and a control unit configured to determine a state of health (SOH) of each of the at least one battery cells based on the battery cell information and determine whether a defect occurs in the at least one battery cells based on an average and a standard deviation of the SOHs. The control unit may be configured to determine that an abnormality has occurred in the cooling control based on a first condition in which the deviation is greater than or equal to a first reference value for a first reference time. The control unit may be further configured to determine, as a reference SOH, a value obtained by excluding the standard deviation from the average of the SOHs and determine that a defect occurs in the battery cell based on that the SOHs of the at least one battery cells are less than the reference SOH. The standard deviation may be determined as a value greater between the standard deviation calculated based on the SOH of each of the at least one battery cells and a preset reference standard deviation. The control unit may be further configured to determine an open circuit voltage (OCV) of the at least one battery cells and determine that a defect occurs in the battery cell based on that the OCV is greater than a reference OCV obtained by excluding an OCV deviation from an average OCV. The control unit may be further configured to determine the SOH of each of the at least one battery cell by applying a current detected by the sensor unit to a current integration method. The control unit may be further configured to transmit the battery cell information including the defect occurring to an external device, based on the determining of that the defect occurs in the at least one battery cells. A battery diagnosis method according to an embodiment includes obtaining battery cell information for each of at least one battery cells, determining a state of health (SOH) of each of the at least one battery cells based on the battery cell information, and determining whether a defect occurs in the at least one battery cells based on an average and a standard deviation of the SOHs. The determining of whether the defect occurs in the at least one battery cells may include determining, as a reference SOH, a value ob