Apparatus for detecting low voltage battery cell foreign object location and analysis method using the same

Abstract

The present disclosure relates to an apparatus for detecting a foreign object location of a low-voltage defective battery cell, including: first and second measurement electrodes disposed on a positive and negative electrode, respectively, of a battery cell to be evaluated, to measure a leakage current; a current measurement device for measuring the leakage current; and a data processing component for processing the measured leakage current data, wherein the first and second measurement electrodes each have a structure of a plurality of unit electrode sets assigned with coordinate information, the current measurement device measures the leakage current flowing through the unit electrodes of the first measurement electrode and the unit electrodes of the second measurement electrode having the same coordinate information and electrically connected, and the data processing component checks the foreign object location from the leakage current data through the coordinate information of the unit electrode having a large leakage current. Accordingly, the detection apparatus of the present disclosure can accurately detect the foreign object location while significantly reducing the workload of detecting the foreign object location.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2021-0184656, filed on December 22, 2021.

[0002] This invention relates to an analyzer capable of accurately identifying the location of foreign matter in a low-voltage battery cell, and a method for analyzing foreign matter in a low-voltage battery cell using the analyzer. Background Technology

[0003] As fossil fuels dwindle and energy prices rise, coupled with increasing concerns about environmental pollution, the demand for environmentally friendly alternative energy sources is becoming a crucial factor in future living. In particular, with technological advancements and the growing demand for mobile devices, the need for secondary batteries as an energy source is rapidly increasing.

[0004] Generally speaking, in terms of battery shape, there is a high demand for prismatic and pouch-type secondary batteries that can be used in products such as thin mobile phones, while in terms of materials, there is a high demand for lithium secondary batteries such as lithium-ion batteries and lithium-ion polymer batteries with high energy density, high discharge voltage and output stability.

[0005] Furthermore, secondary batteries can be classified according to the structure of the electrode assembly, which includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. Representatively, there are jelly roll (wound) electrode assemblies, stacked (layered) electrode assemblies, and stacked folded electrode assemblies. The jelly roll (wound) electrode assembly has a structure in which long sheet-shaped positive and negative electrodes are wound together with a separator in between. In the stacked (layered) electrode assembly, multiple positive and negative electrodes cut to a predetermined size are stacked sequentially with a separator in between. The stacked folded electrode assembly has a structure in which a single cell, such as a dual-cell or full-cell, is wound together, wherein a predetermined unit of positive and negative electrodes is stacked with a separator in between.

[0006] In addition, a secondary battery is manufactured by injecting an electrolyte solution (a liquid electrolyte) while the electrode assembly is housed inside the battery container and then sealing the battery container.

[0007] Due to various reasons during assembly, manufacturing, or use, manufactured secondary batteries may have various defects. Among them, the phenomenon where a manufactured battery exhibits a voltage drop greater than its self-discharge rate is called low voltage.

[0008] This low-voltage defect is usually caused by foreign objects located inside the battery. Typically, when a metallic foreign object is present in the positive electrode, it grows into dendrites in the negative electrode, and these dendrites cause an internal short circuit in the secondary battery. As a result, the internal short circuit of the secondary battery leads to battery malfunction, damage, fire, etc.

[0009] To identify the type of foreign matter causing this low-voltage defect, foreign matter is sampled from the low-voltage defective battery cell, and image and elemental analysis are performed using FE-SEM-EDS. Traditionally, to sample foreign matter causing low voltage, the open-circuit voltage (OCV) is monitored in the low-voltage battery cell on a per-cell basis. Cells with a voltage drop exceeding the self-discharge are selected, and foreign matter in the corresponding cell and its adjacent cells is visually identified before sampling. However, this traditional method is time-consuming because foreign matter must be visually detected, and therefore, fatigue from analysis accumulates over long-term performance, making it unlikely to find foreign matter causing actual leakage current.

[0010] In addition, another method for sampling foreign objects is the HI-POT test. The HI-POT test uses liquid nitrogen to freeze the electrolyte, then applies a high voltage to induce combustion by concentrating the current at a potential short-circuit location. The foreign object is then sampled after the location of the burned individual cell is examined by disassembling the battery cell. However, there is a problem: due to the explosive force caused by the applied high voltage, there is a significant concern about the loss of information about the sample. Summary of the Invention

[0011] [Technical Issues]

[0012] The present invention aims to solve the above-mentioned problems of the prior art and to provide a device and method for detecting the location of foreign objects, wherein the device can solve the fatigue caused by time-consuming analysis and has a high probability of detecting foreign objects when searching for their location by visual inspection.

[0013] [Technical Solution]

[0014] The apparatus for detecting the location of foreign objects in a low-voltage battery cell according to the present invention comprises: a first measuring electrode and a second measuring electrode, respectively disposed on the positive electrode and negative electrode of the battery cell to be evaluated, for measuring leakage current; a current measuring device for measuring the leakage current; and a data processing unit for processing the measured leakage current data, wherein the first measuring electrode and the second measuring electrode each have a structure for distributing a plurality of unit electrode sets with coordinate information, the current measuring device measures the leakage current flowing through the unit electrodes of the first measuring electrode and the second measuring electrode having the same coordinate information and being electrically connected, and the coordinate information of the unit electrode having a large leakage current, and the data processing unit checks the location of the foreign object based on the leakage current data.

[0015] The apparatus for detecting the location of foreign objects in a low-voltage battery cell according to an exemplary embodiment of the present invention further includes: a first clamp and a second clamp, wherein the first clamp and the second clamp are configured to squeeze the laminate from both sides with the first measuring electrode, the second measuring electrode, and the laminate of the battery cell to be evaluated between the first clamp and the second clamp.

[0016] In an exemplary embodiment of the present invention, the battery cell is a single cell that has been confirmed to have low voltage defects, and is a single cell having a positive electrode / separator / negative electrode structure.

[0017] In an exemplary embodiment of the present invention, the unit electrodes are arranged in a matrix in the horizontal and vertical directions, and have coordinate information according to the matrix.

[0018] In an exemplary embodiment of the present invention, the unit electrodes have the same volume and shape, and have a cuboid or hexahedral shape.

[0019] In an exemplary embodiment of the present invention, the unit electrodes of the first measuring electrode and the second measuring electrode having the same coordinate information constitute a single current circuit, and the current measuring device is configured to simultaneously measure the leakage current of each current circuit corresponding to the number of coordinate information.

[0020] In an exemplary embodiment of the present invention, a printed circuit board (PCB) is further included, the PCB including a plurality of current circuits corresponding to the number of coordinate information.

[0021] In an exemplary embodiment of the present invention, the printed circuit board is a flexible printed circuit board (FPCB).

[0022] The apparatus for detecting the location of foreign matter in a low-voltage battery cell according to an exemplary embodiment of the present invention further includes an amplifier for amplifying leakage current.

[0023] The apparatus for detecting the location of foreign matter in a low-voltage battery cell according to an exemplary embodiment of the present invention further includes a power source for applying external power to a current circuit formed by the unit electrode of the first measuring electrode and the unit electrode of the second measuring electrode.

[0024] A method for detecting the location of a foreign object in a low-voltage battery cell according to an exemplary embodiment of the present invention includes: screening a battery cell comprising a plurality of individual cells for a low-voltage individual cell that causes the low voltage; and using a device for detecting the location of a foreign object, identifying the location of the foreign object by measuring the leakage current of the screened low-voltage individual cell.

[0025] In an exemplary embodiment of the present invention, screening low-voltage single cells includes: inserting an insulating film by disconnecting the negative electrode portion of the low-voltage battery cell, cutting the negative electrode terminal welding component, and inserting an insulating film between each negative electrode; measuring the initial open-circuit voltage (OCV1) of each negative electrode; applying pressure to the low-voltage battery cell; and screening low-voltage single cells by monitoring the open-circuit voltage of each negative electrode over time.

[0026] A method for analyzing foreign matter in a low-voltage defective battery cell according to an exemplary embodiment of the present invention includes: screening a battery cell comprising a plurality of individual cells for low-voltage individual cells that cause low voltage; using the detection apparatus according to claim 1, identifying the location of the foreign matter by measuring the leakage current of the screened low-voltage individual cells; and analyzing the type of foreign matter by sampling near the identified location of the foreign matter.

[0027] [Beneficial Effects]

[0028] The apparatus and method for detecting the location of foreign objects in a low-voltage battery cell according to the present invention measure leakage current by means of multiple cell electrodes having coordinate information, and have the effect of quickly and accurately detecting the location of foreign objects based on the coordinate information of cell electrodes with large leakage current. Attached Figure Description

[0029] Figure 1 This is a side view of a device for detecting the location of foreign objects in a low-voltage battery cell according to an exemplary embodiment of the present invention.

[0030] Figure 2 This is a top view of a device for detecting the location of foreign objects in a low-voltage battery cell according to an exemplary embodiment of the present invention.

[0031] Figure 3 This is a flowchart of a method for detecting the location of foreign matter in a low-voltage battery cell according to an exemplary embodiment of the present invention.

[0032] Figure 4This is a flowchart of a low-voltage single-cell screening step according to an exemplary embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram showing the leakage current measured by the analyzer of the present invention.

[0034] Figure 6 This is a flowchart of a foreign matter analysis method for low-voltage defective battery cells according to an exemplary embodiment of the present invention.

[0035] [Figure Labels]

[0036] 10: Battery cell (single cell)

[0037] 100: Equipment used to detect the location of foreign objects in low-voltage battery cells.

[0038] 110: First measuring electrode

[0039] 120: Second measuring electrode

[0040] 130: First clamp

[0041] 140: Second clamp

[0042] 150: Current measuring device

[0043] 160: Data processing unit

[0044] 170: Printed Circuit Board

[0045] 111, 121: Unit electrodes

[0046] a1~a10, b1~b10, c1~c10, d1~d10: Coordinate information Detailed Implementation

[0047] Because the present invention can be applied with various modifications and has various embodiments, specific embodiments will be illustrated and described in detail in the specification. However, it should be understood that the present invention is not limited to the specific embodiments, but includes all modifications, equivalents, or substitutions that fall within the spirit and scope of the present invention.

[0048] The terminology used in this invention is for describing particular embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly specifies otherwise. Terms such as “comprising” or “having” are used herein to specify the presence of features, numbers, steps, actions, components or elements or combinations thereof described in the specification, and it should be understood that the possibility of the presence or addition of one or more other features, numbers, steps, actions, components or elements or combinations thereof is not excluded in advance.

[0049] The following describes in detail the apparatus according to the invention for detecting the location of foreign objects in a low-voltage battery cell.

[0050] Figure 1 This is a side view of a device for detecting the location of foreign objects in a low-voltage battery cell according to an exemplary embodiment of the present invention. Figure 2 This is a top view of an apparatus for detecting the location of foreign objects in a low-voltage battery cell according to an exemplary embodiment of the present invention. Referring to these figures, the apparatus 100 for detecting the location of foreign objects in a low-voltage battery cell according to the present invention includes: a first measuring electrode 110 and a second measuring electrode 120, respectively disposed on the positive electrode 11 and the negative electrode 12 of the battery cell 10 to be evaluated, for measuring leakage current; a current measuring device 150 for measuring leakage current; and a data processing unit 160 for processing the measured leakage current data.

[0051] The battery cell 10 is located between the first measuring electrode 110 and the second measuring electrode 120, and correspondingly, the first measuring electrode 110 faces the positive electrode 11 of the battery cell 10, and the second measuring circuit 120 faces the negative electrode 12.

[0052] The battery cell can be a single cell, and this single cell has a structure in which the positive electrode / separator / negative electrode are stacked. Because the device of the present invention for detecting foreign object locations is used to find foreign object locations in low-voltage defective battery cells, the single cell is a single cell that has been confirmed to have a low-voltage defect.

[0053] The first measuring electrode 110 and the second measuring electrode 120 are electrically connected, and because they are in direct contact with the low-voltage battery cell between them, when a leakage current is induced in the low-voltage battery cell, the leakage current flows through the first measuring electrode 110 and the second measuring electrode 120. Furthermore, the current measuring device 160 measures the leakage current flowing through the first measuring electrode and the second measuring electrode.

[0054] To detect the location of foreign objects causing leakage current in a low-voltage battery cell, the first measuring electrode 110 and the second measuring electrode 120 have a structure that aggregates a plurality of unit electrodes 111, 121, each assigned coordinate information. The plurality of unit electrodes 111 constituting the first unit electrode are arranged in a matrix along the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction), and thus have coordinate information according to the matrix. Therefore, the coordinate information indicates the location information of the foreign object in the first and second measuring electrodes.

[0055] refer to Figure 2In the first measuring electrode 110, a plurality of unit electrodes 111 are arranged in a matrix along the vertical direction (Y-axis direction) and the horizontal direction (X-axis direction), and similarly, in the second measuring electrode 120, a plurality of unit electrodes 121 are arranged in a matrix along the vertical direction (Y-axis direction) and the horizontal direction (X-axis direction).

[0056] For example, the unit electrodes 111 constituting the first measuring electrode are arranged in rows a, b, c, d along the vertical direction and columns 1, 2, 3...10 along the horizontal direction. The coordinate information of a1 can be assigned to the unit electrode located in row a, column 1, and the coordinate information of d10 can be assigned to the unit electrode located in row d, column 10. The method for assigning coordinate information to the unit electrodes 121 constituting the second measuring electrode is the same as described above.

[0057] Furthermore, the unit electrodes of the first measuring electrode and the second measuring electrode, which have the same coordinate information, are electrically connected to form a current circuit, and the current measuring device measures the leakage current flowing through the unit electrodes of the first measuring electrode and the second measuring electrode, which have the same coordinate information.

[0058] Specifically, the unit electrode a1 of the first measuring electrode and the unit electrode b2 of the second measuring electrode form a pair to be electrically connected, and the unit electrode b1 of the first measuring electrode and the unit electrode b2 of the second measuring electrode form a pair to be electrically connected. Although Figure 2 Although not shown, the unit electrodes assigned with the remaining coordinate information are also paired and electrically connected in this manner. Therefore, by configuring multiple current circuits corresponding to the number of coordinate information points, and by having the current measuring device simultaneously measure the leakage current flowing through each of the multiple current circuits, it is possible to measure the leakage current based on the coordinate information.

[0059] Since the location of foreign objects should be determined based on coordinate information, it is preferable that the multiple unit electrodes assigned to the coordinate information have the same volume and shape. This is because if the volume and shape of the unit electrodes are not the same, the leakage current will be affected by these factors, and therefore, it may be difficult to detect the location of foreign objects by simply comparing leakage currents.

[0060] Using the coordinate information of the unit electrode with a large leakage current, the data processing unit 160 checks the location of the foreign object based on the leakage current data measured by the current measuring device. The leakage current measured in the current circuit formed by the unit electrode at the location where the foreign object exists is greater than the leakage current measured in the current circuit formed by other unit electrodes.

[0061] Figure 5This is a schematic diagram illustrating the leakage current measured by the analyzer of the present invention. The data processing unit 160 can process multiple leakage current values ​​measured by the current measuring device 150 according to coordinate information and print them out, such as... Figure 5 As shown. Therefore, by checking the coordinate information of objects with large leakage currents, it can be determined that there are foreign objects at the corresponding coordinate locations.

[0062] Therefore, because the device of the present invention for detecting the location of foreign objects in low-voltage battery cells can accurately detect the location of leakage current in the low-voltage battery cell to be inspected by means of unit electrodes assigned with coordinate information, it has the effect of significantly improving workload, significantly enhancing time and analysis accuracy when suspicious foreign objects are found or multiple suspicious locations are sampled, compared with conventional methods of visual inspection and inspection of foreign object locations.

[0063] In one specific example, the device for detecting the location of foreign objects in a low-voltage battery cell according to the present invention may further include a first clamp 130 and a second clamp 140. The first clamp 130 and the second clamp 140 may be configured to compress the laminate from both sides of the laminate while the first measuring electrode 110 and the second measuring electrode 120 and the laminate of the battery cell 10 to be evaluated are between the first clamp 130 and the second clamp 140.

[0064] Pressure is applied to both sides of the laminate of the first measuring electrode 110, the second measuring electrode 120, and the battery cell 10 to be evaluated in order to induce leakage current to the greatest extent. When the laminate is pressured, current is applied to the positive and negative electrodes at the location where foreign matter is present, and the battery cell to be evaluated requires current to maintain its voltage, thus generating leakage current. Furthermore, the leakage current generated in this way flows through the first and second measuring electrodes in contact with the positive and negative electrodes, and therefore the leakage current can be measured by a current measuring device.

[0065] The structure of the first clamp 130 and the second clamp 140 is not limited to any particular structure or shape, as long as they can apply pressure to the stack of the first measuring electrode 110, the second measuring electrode 120, and the battery cell 10 to be evaluated.

[0066] In a specific example, the first clamp 130 and the second clamp 140 may have a rectangular plate shape, and the size of the pressure surface may correspond to the area faced by the stack of the first measuring electrode 110, the second measuring electrode 120, and the battery cell 10 to be evaluated.

[0067] In one specific example, the device according to the invention for detecting the location of foreign objects in a low-voltage battery cell may further include an amplifier that amplifies the leakage current. This is to increase the ability to distinguish leakage current values ​​when the leakage current value is low.

[0068] Furthermore, according to another specific example, a device for detecting the location of foreign objects in a low-voltage battery cell may include a power source for applying external power to a current circuit formed by the unit electrodes of a first measuring electrode and a second measuring electrode. Adding a power source also increases the ability to distinguish leakage current values ​​when they are low.

[0069] In a specific example, the device according to the invention for detecting the location of foreign objects in a low-voltage battery cell may include a printed circuit board (PCB) incorporating current circuits corresponding to the number of coordinate information points. Therefore, wires for electrically connecting the unit electrodes of the first and second measuring electrodes are not necessary, these circuits are stable, and uniformity and reliability are increased. Furthermore, the printed circuit board may be a flexible printed circuit board (FPCB). Flexible printed circuit boards offer advantages such as the ability to achieve three-dimensional wiring, miniaturization, and weight reduction.

[0070] The method for detecting the location of foreign objects in a low-voltage battery cell according to the present invention is described in detail below.

[0071] Figure 3 This is a flowchart of a method for detecting the location of foreign matter in a low-voltage battery cell according to an exemplary embodiment of the present invention. (Reference) Figure 3 The method for detecting the location of a foreign object in a low-voltage battery cell according to the present invention includes: screening (S10) low-voltage single cells that cause low voltage in a battery cell comprising a plurality of single cells; and identifying (S20) the location of the foreign object by measuring the leakage current of the screened low-voltage single cells using a device for detecting the location of the foreign object.

[0072] Stacked or stacked / folded battery cells include a structure in which a majority of single cells having positive electrode / separator / negative electrode structures are stacked, and the screening of low-voltage single cells (S10) is a step of screening single cells containing foreign matter in low-voltage battery cells.

[0073] Figure 4 This is a flowchart of a single-monomer screening step according to an exemplary embodiment of the present invention. (Reference) Figure 4 The screening of individual cells (S10) includes: inserting an insulating film (S11), cutting the negative electrode terminal welding component by disconnecting the negative electrode portion of the low-voltage battery cell, and inserting an insulating film between each negative electrode; initial voltage measurement (S12), measuring the initial open-circuit voltage (OCV1) of each negative electrode; applying pressure (S13), applying pressure to the low-voltage battery cell; and screening (S14) low-voltage individual cells by monitoring the open-circuit voltage of each negative electrode over time.

[0074] Insert insulating film (S11) Insert insulating film for insulation between individual cells so that open circuit voltage (OCV) can be measured on a per-cell basis among multiple individual cells.

[0075] The initial voltage measurement step (S12) is performed for comparison of the voltage drop. Low-voltage cells are those whose voltage drop exceeds their self-discharge rate, and cells exhibiting a large voltage drop over time are selected as low-voltage single cells. To compare the voltage drop, the initial voltage is measured and recorded, and then low-voltage single cells are selected by calculating the voltage difference (the amount of voltage drop) over time. Here, the open-circuit voltage is measured for all negative electrodes.

[0076] After measuring the initial open-circuit voltage, pressure is applied to the individual battery cells (S13). This pressure application step is to accelerate the voltage drop. The pressure application device is not particularly limited, as long as it can accelerate the voltage drop; specifically, it could be a compression clamp, including a pair of compression plates capable of applying pressure to both sides of the battery cell. Because the electrolyte solution may leak during the pressure application step, it is preferable to encapsulate and seal the electrolytic cell in a sealing material before performing the pressure application step. This sealing material is not particularly limited, as long as it is a material capable of preventing electrolyte solution leakage; specifically, it could be a plastic sealing material.

[0077] In the screening step (S14), the open-circuit voltage of each negative electrode is measured over time, the amount of voltage drop is calculated, and single cells including negative electrodes with large voltage drops are screened as low-voltage battery cells.

[0078] In this way, after screening out the individual cells that cause low voltage among the low voltage battery cells, the step of confirming the location of the foreign object causing the leakage current is performed by measuring the leakage current of the individual cell using the device described above for detecting the location of the foreign object (S20).

[0079] Since the aforementioned device for detecting foreign object location detects the foreign object location by measuring the leakage current of a current circuit composed of a first measuring electrode and a second measuring electrode having the same coordinate information, and by using coordinate information showing a large leakage current (wherein, the first measuring electrode and the second measuring electrode for measuring the leakage current have a structure that distributes multiple unit electrode sets with coordinate information), the method for detecting foreign object location according to the present invention has the effect of quickly and accurately detecting the location of foreign objects that cause low voltage.

[0080] The following describes a method for analyzing foreign matter in low-voltage battery cells according to the present invention.

[0081] Figure 6This is a flowchart of a foreign matter analysis method for low-voltage defective battery cells according to an exemplary embodiment of the present invention. (Reference) Figure 6 The method for analyzing foreign matter in low-voltage battery cells according to the present invention includes: screening (S31) low-voltage single cells, screening single cells that cause low voltage in a battery cell comprising a plurality of single cells; identifying (S32) the location of the foreign matter by measuring the leakage current of the screened low-voltage single cells using the detection device according to claim 1; and analyzing (S33) the type of foreign matter by sampling near the identified foreign matter location.

[0082] Since the specific details of the steps for screening a single individual (S31) and specifying the location of the foreign object (S32) have already been described above, further descriptions will be omitted.

[0083] Analyzing the type of foreign object (S33) involves sampling near the location of a specified foreign object and using the sampled sample to analyze the type of the foreign object. Specifically, the FE-SEM-EDS analysis method can be used. Here, sampling refers to preparing a sample that includes the specified foreign object.

[0084] The FE-SEM-EDS analytical method utilizes equipment for high-resolution, high-magnification, and low-damage surface analysis, enabling microstructure analysis, morphology, profile analysis, and particle size analysis. Furthermore, it allows for qualitative and quantitative analysis of unknown samples using EDS equipment. The analytical method of this invention improves analytical accuracy because the sampled material has a high probability of containing foreign matter that causes low voltage.

[0085] As described above, the present invention has been described with reference to exemplary embodiments; however, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as described in the appended claims.

[0086] Therefore, the technical scope of this invention should not be limited to the detailed description in the specification, but should be defined by the claims.

Claims

1. A device for detecting the location of foreign objects in a low-voltage battery cell, comprising: The first measuring electrode and the second measuring electrode are respectively disposed on the positive electrode and the negative electrode of the battery cell to be evaluated, so as to measure the leakage current. A current measuring device, wherein the current measuring device is used to measure leakage current; as well as A data processing unit is used to process measured leakage current data, wherein... The first measuring electrode and the second measuring electrode each have a structure that assigns multiple unit electrode sets with coordinate information. The current measuring device measures the leakage current flowing through the unit electrodes of the first measuring electrode and the second measuring electrode, which have the same coordinate information and are electrically connected. Using the coordinate information of the unit electrode with a large leakage current, the data processing unit checks the location of the foreign object based on the leakage current data.

2. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, further comprising: First clamp and second clamp, wherein The first clamp and the second clamp are configured to compress the stack from both sides with the first measuring electrode, the second measuring electrode, and the battery cell to be evaluated stacked between the first clamp and the second clamp.

3. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, wherein... The battery cell is a single cell that has been confirmed to have low voltage defects, and it is a single cell with a positive electrode / separator / negative electrode structure.

4. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, wherein... The unit electrodes are arranged in a matrix in the horizontal and vertical directions and have coordinate information based on the matrix.

5. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, wherein... The unit electrodes have the same volume and shape, and are cuboid or hexahedral in shape.

6. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, wherein... The unit electrodes of the first measuring electrode and the second measuring electrode, which have the same coordinate information, constitute a single current circuit, and the current measuring device is configured to simultaneously measure the leakage current of each current circuit corresponding to the number of coordinate information.

7. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 6, further comprising: A printed circuit board (PCB) includes multiple current circuits corresponding to the number of coordinate information.

8. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 7, wherein... The printed circuit board is a flexible printed circuit board (FPCB).

9. The device for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, further comprising: An amplifier used to amplify leakage current.

10. The apparatus for detecting the location of foreign objects in a low-voltage battery cell according to claim 1, further comprising: A power source for applying external power to a current circuit formed by the unit electrodes of the first measuring electrode and the second measuring electrode.

11. A method for detecting the location of foreign matter in a low-voltage battery cell, the method comprising: Screening for low-voltage single cells that cause low voltage among battery cells comprising multiple single cells; as well as Using the detection device according to claim 1, the location of the foreign object is identified by measuring the leakage current of the screened low-voltage single cell.

12. The method for detecting foreign object locations in a low-voltage battery cell according to claim 11, wherein screening low-voltage individual cells includes: The insulating film is inserted by disconnecting the negative electrode portion of the low-voltage battery cell, cutting the welding components of the negative electrode terminals, and inserting an insulating film between each negative electrode. Initial voltage measurement of the initial open-circuit voltage (OCV1) of each negative electrode; The pressure applied to the low-voltage battery cell; as well as Low-voltage single cells are screened by monitoring the open-circuit voltage of each negative electrode over time.

13. A method for analyzing foreign matter in low-voltage defective battery cells, the method comprising: Screening for low-voltage single cells that cause low voltage among battery cells comprising multiple single cells; Using the detection apparatus according to claim 1, the location of the foreign object is determined by measuring the leakage current of the screened low-voltage single cell; and The type of foreign object is analyzed by sampling near the specified location of the foreign object.

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