Battery pack determination method

Abstract

Provided is a battery pack judgment method including: a battery pack manufacturing step in which a battery pack is manufactured by joining a battery cell and a wire; a battery cell charging and discharging step in which the battery cell is charged and discharged by the wire; a thermal image photographing step in which a thermal image of the battery pack is photographed; a thermal image reading step in which a joining state of a joining portion of the battery cell and the wire is read from the photographed thermal image data; a magnetic field image photographing step in which a magnetic field image of the battery pack is photographed; a magnetic field image reading step in which the joining state of the joining portion of the battery cell and the wire is read from the photographed magnetic field image data; and a wire joining state defect determination step in which the joining state of the battery cell and the wire is finally determined by combining thermal image reading result information obtained in the thermal image reading step and magnetic field image reading result information obtained in the magnetic field image reading step.

Description

Technical Field

[0001] This disclosure relates to a battery pack identification method, and more specifically, to a battery pack identification method capable of accurately determining the connection state between multiple battery cells and multiple wires connecting the battery cells in a battery pack. Background Technology

[0002] A battery pack is manufactured by storing multiple individual battery cells in a casing and connecting them using busbars and wires. Defects may occur at the junctions of the battery cells and wires within the battery pack.

[0003] When a defect occurs at the junction of the battery cell and the conductor, the corresponding battery cell will exhibit a large change in internal resistance during charging or discharging. For example, the corresponding battery cell will have a higher voltage during charging than normal battery cells surrounding it, and a lower voltage during discharging than normal battery cells surrounding it.

[0004] Furthermore, when individual battery cells are continuously charged or discharged, the total output of the battery pack decreases, and short circuits and fires may occur in the individual battery cells. Therefore, during the battery pack manufacturing process, the bonding condition of the joints between the battery cells and the wires must be checked to determine the bonding condition of the joints.

[0005] However, a battery pack contains hundreds of individual battery cells and hundreds of wires connecting them. Therefore, it is impossible to accurately inspect the bonding status of each of the hundreds of individual battery cells and wires.

[0006] The background technology of this invention is disclosed in the following patent documents.

[0007] (Patent Document 1) KR10-2019-0011096A

[0008] (Patent Document 2) KR10-2020-0056715A Summary of the Invention

[0009] Technical issues

[0010] This disclosure provides a battery pack determination method, which can accurately determine the connection state between multiple battery cells in the battery pack and multiple wires connecting the battery cells.

[0011] Technical solution

[0012] According to an exemplary embodiment, a battery pack determination method includes: a battery pack manufacturing step, manufacturing a battery pack by combining and connecting battery cells and wires; a battery cell charging and discharging step, charging and discharging battery cells through wires; a battery pack thermal imaging step, capturing a thermal image of the battery pack; a thermal image reading step, reading the bonding state of the joint between the battery cells and wires from the captured thermal image data; a battery pack magnetic field image capturing step, capturing a magnetic field image of the battery pack; a magnetic field image reading step, reading the bonding state of the joint between the battery cells and wires from the captured magnetic field image data; and a wire bonding state defect determination step, which ultimately determines the bonding state of the battery cells and wires by combining the thermal image reading result information obtained in the thermal image reading step and the magnetic field image reading result information obtained in the magnetic field image reading step.

[0013] The thermal imaging step of the battery pack can generate a thermal image by photographing a predetermined plane on which wires are disposed, and the photographed thermal image can have a predetermined pixel size smaller than at least one of the thickness of the wires and the size of the joint portion of the wires.

[0014] The thermal image reading step may include: a thermal image contour generation step, which extracts a predetermined contour from the captured thermal image and generates the shape of the joint portion of the battery cell and the wire; a joint portion temperature reading step, which reads the temperature of the joint portion of the battery cell and the wire from the captured thermal image data as either high temperature or low temperature; a joint portion as an abnormal connection determination step, which determines the joint state of the joint portion as an abnormal connection state when the temperature of the joint portion of the battery cell and the wire is higher than a predetermined reference temperature; a joint portion as a normal connection determination step, which determines the joint state of the joint portion as a normal connection state when the temperature of the joint portion of the battery cell and the wire is lower than the reference temperature; and a thermal image reading result information generation step, which generates thermal image reading result information by matching the position information of the joint portion with the joint state of the joint portion.

[0015] The battery pack magnetic field image capture step can generate a magnetic field image by capturing the same predetermined plane as the one captured for obtaining a thermal image, and the captured magnetic field image can have a predetermined pixel size determined corresponding to the pixel size of the captured thermal image.

[0016] The magnetic field image reading step may include: a magnetic field image contour generation step, which generates the shape of the junction of the battery cell and the wire in the captured magnetic field image using the contour extracted from the thermal image reading step; a junction magnetic field strength reading step, which reads the magnetic field strength of the junction of the battery cell and the wire from the captured magnetic field image data; a determination step for treating the junction as a normal connection, which determines the junction strength as a normal connection state when the magnetic field strength of the junction of the battery cell and the wire is greater than a predetermined reference strength; a determination step for treating the junction as an abnormal connection, which determines the junction state as an abnormal connection state when the magnetic field strength of the junction of the battery cell and the wire is less than the reference strength; and a magnetic field image reading result information generation step, which generates magnetic field image reading result information by matching the position information of the junction with the junction state of the junction.

[0017] The steps for determining the defect in the bonding state of the conductor can be achieved by comparing the results of thermal imaging and magnetic field imaging, and finally determining the bonding state of the battery cell and the conductor to be selected from the normal connection state, abnormal connection state, and abnormal disconnection state.

[0018] By comparing the results of thermal imaging and magnetic field image readings, the steps for determining the defective connection state of the conductor can be finalized as follows: when the connection state of the battery cell and the conductor is considered an abnormal connection state, the connection state of the connection is determined to be an abnormal connection state; when the connection state of the battery cell and the conductor is considered a normal connection state, the connection state of the connection is determined to be a normal connection state; when the connection state of the battery cell and the conductor is considered either a normal connection state or an abnormal connection state, the connection state of the connection is determined to be an abnormal disconnection state.

[0019] While performing the charging and discharging steps of individual battery cells, the thermal imaging steps of the battery pack and the magnetic field imaging steps of the battery pack can be performed simultaneously.

[0020] While performing individual battery cell charging and discharging steps, thermal imaging of the battery pack and magnetic field imaging of the battery pack can be performed in a predetermined sequence and at predetermined time differences.

[0021] Beneficial effects

[0022] According to an exemplary embodiment, the bonding state between individual battery cells and their connected wires in a battery pack can be accurately determined by combining thermal image readings and magnetic field image readings of the battery pack. Therefore, wires with defective bonding states will not be missed from the determination results. That is, the bonding state can be determined more accurately than when only thermal images or only magnetic field images are read. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating a battery pack determination method according to an exemplary embodiment.

[0024] Figure 2 and Figure 3 This is an exemplary schematic diagram illustrating the battery pack manufacturing steps according to an exemplary embodiment.

[0025] Figure 4 This is an exemplary schematic diagram illustrating the charging and discharging steps of a single battery cell according to an exemplary embodiment.

[0026] Figure 5 This is an exemplary schematic diagram illustrating the steps of thermal imaging of a battery pack according to an exemplary embodiment.

[0027] Figure 6 This is a conceptual diagram illustrating a thermal image reading step according to an exemplary embodiment.

[0028] Figure 7 This is an exemplary schematic diagram illustrating the steps of capturing a magnetic field image of a battery pack according to an exemplary embodiment.

[0029] Figure 8 This is a conceptual diagram illustrating a magnetic field image reading step according to an exemplary embodiment. Detailed Implementation

[0030] In the following, exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings. However, the invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the dimensions of layers and regions are enlarged for clarity. Throughout the specification, the same reference numerals denote the same elements.

[0031] In the following description, exemplary embodiments will be described in detail with reference to the accompanying drawings.

[0032] 1. A battery pack determination method according to an exemplary embodiment

[0033] Figure 1 This is a flowchart illustrating a battery pack determination method according to an exemplary embodiment.

[0034] like Figure 1As shown, the battery pack determination method according to an exemplary embodiment includes: a battery pack manufacturing step S100, a battery cell charging and discharging step S200, a battery pack thermal imaging step S300, a thermal image reading step S400, a battery pack magnetic field image capturing step S500, a magnetic field image reading step S600, and a wire bonding state defect determination step S700.

[0035] 1.1 Battery pack manufacturing step S100

[0036] Figure 2 and Figure 3 This is an exemplary schematic diagram illustrating the battery pack manufacturing steps according to an exemplary embodiment.

[0037] The battery pack manufacturing process involves connecting individual battery cells 30 and wires W to create the battery pack B. The battery pack manufacturing process may include a individual battery cell storage step S110 and a wire connection step S120.

[0038] 1.1.1. Battery cell storage step S110

[0039] Reference Figure 2 In the battery cell storage step, a battery pack casing 10, a battery cell holder 20, multiple battery cells 30, and a busbar 40 are prepared. The battery cell holder 20 can then be stored in the battery pack casing 10, and the multiple battery cells 30 can be stored in the battery cell holder 20. Furthermore, the busbar 40 can be mounted on the multiple battery cells 30.

[0040] Here, the battery pack housing 10 can have a rectangular container shape with an internally open upper surface. Alternatively, the battery pack housing 10 can have various shapes. The battery cell holder 20 can be made of various materials and various shapes capable of securing multiple battery cells 30. The battery cell 30 can be a cylindrical secondary battery cell extending in the vertical direction. Alternatively, the battery cell 30 can be a can-shaped secondary battery cell extending in the vertical direction. The battery cells 30 can be arranged horizontally to form a predetermined arrangement.

[0041] 1.1.2. Wire splicing step S120

[0042] Reference Figure 3 The wire bonding step can manufacture the battery pack B such that multiple wires W are respectively arranged in multiple through holes H defined in the busbar 40 to connect multiple battery cells 30 and the busbar 40. Then, by performing wire bonding, one end of each of the multiple wires W is connected to the multiple battery cells 30 respectively, and the other end of each of the multiple wires W is connected to the busbar 40.

[0043] Here, when the connection between the battery cell 30 and the wire W is damaged, one end of the wire W cannot properly contact the battery cell 30. Therefore, the connection may have an abnormally small area. Furthermore, the connection may completely break off.

[0044] Alternatively, the connection between the busbar 40 and the other end of the conductor W may be damaged, and the connection may be completely broken. Even in this case, the connection status of the connection can be determined using the same method through the following steps.

[0045] 1.2. Battery cell charging and discharging steps S200

[0046] Figure 4 This is an exemplary schematic diagram illustrating the charging and discharging steps of a single battery cell according to an exemplary embodiment.

[0047] Reference Figure 4 The battery cell charging and discharging steps are performed by charging and discharging the battery cells via wires. The battery cell charging and discharging steps may include: placing the manufactured battery pack B on the support 50; connecting the charging and discharging unit 60 to the input and output terminals (not shown) of the battery pack B, which are connected to the battery cells 30 via wires W; and charging or discharging the battery cells 30 in the battery pack B by using the charging and discharging unit 60.

[0048] Here, the charging / discharging unit 60 may include a predetermined charging source (not shown) and a predetermined discharging rod (not shown). When the battery cell 30 is charged or discharged using the charging / discharging unit 60, a current is generated through the input and output terminals, the wires W, and the battery cell 30. Here, if the connection between the battery cell 30 and the wires W is damaged, an abnormal current may be generated, or no current may be generated.

[0049] For example, when the junction of the battery cell 30 and the wire W is damaged, resulting in an abnormally small area at the junction, the resistance of the junction may increase, and an abnormal current may be generated. In this case, when current flows through the junction, the temperature of the junction may be higher than the temperature of the surrounding area.

[0050] Additionally, when the junction between the battery cell 30 and the wire W is completely disconnected, no current may be generated.

[0051] When the junction of the battery cell 30 and the wire W is undamaged, or when the junction of the battery cell 30 and the wire W is completely disconnected, the temperature of the junction may be lower than the temperature of the damaged junction.

[0052] In addition, when the junction of the battery cell 30 and the wire W is damaged or completely disconnected, the current intensity at the junction may be less than the current intensity of the surrounding portion or its value may be 0, and the magnetic field intensity at the junction may be less than the magnetic field intensity of the surrounding portion.

[0053] When the junction of the battery cell 30 and the wire W is not damaged, the current intensity at the junction can be greater than that in the case described above when current flows through the junction. Therefore, the magnetic field strength can also be greater than that in the case described above.

[0054] 1.3. Battery Pack Thermal Imaging Procedure S300

[0055] Figure 5 This is an exemplary schematic diagram illustrating the steps of thermal imaging of a battery pack according to an exemplary embodiment.

[0056] The thermal imaging step of the battery pack includes taking a thermal image of the battery pack B. The thermal imaging step of the battery pack may include: placing the battery pack B on the support 50 and arranging the thermal imaging unit 70 above the support 50; and taking a thermal image of a predetermined plane (e.g., the top surface of the battery pack B) on which the wires W are disposed by using the thermal imaging unit 70.

[0057] For example, the battery pack B can be placed on a support 50 having a top surface capable of supporting the battery pack B, and then the thermal imaging unit 70 connected to the determination unit 80 can be moved above the battery pack B. Furthermore, infrared radiation emitted from the top surface of the battery pack B can be detected using a plurality of detection elements (not shown) arranged at a predetermined focal plane forming the focal plane of the thermal imaging unit 70, and a thermal image of the top surface of the battery pack B can be captured.

[0058] Here, the captured thermal image may have a predetermined pixel size determined corresponding to the size of the conductor W. For example, the captured thermal image may have a predetermined pixel size smaller than at least one of the thickness of the conductor W and the size of the joint portion of the conductor W, in order to distinguish the conductor W in the captured thermal image.

[0059] Alternatively, the thermal image taken can have a predetermined pixel size that is less than 30 mm in diameter of the battery cell.

[0060] 1.4. Thermal image reading step S400

[0061] Figure 6 This is a conceptual diagram illustrating a thermal image reading step according to an exemplary embodiment.

[0062] The thermal image reading step reads the bonding state of the junction between the battery cell 30 and the wire W from the captured thermal image data DB1. This step can be performed in the determination unit 80.

[0063] Here, the thermal image reading step may include: a thermal image contour generation step, which extracts a predetermined contour from the captured thermal image and generates the shape of the joint portion of the battery cell 30 and the wire W; a joint portion temperature reading step, which reads the temperature of the joint portion of the battery cell 30 and the wire W from the captured thermal image data DB1 as one of high temperature and low temperature; a joint portion as an abnormal connection determination step, which determines the joint state of the joint portion as an abnormal connection state when the joint portion of the battery cell and the wire has a high temperature; a joint portion as a normal connection determination step, which determines the joint state of the joint portion as a normal connection state when the joint portion of the battery cell and the wire has a low temperature; and a thermal image reading result information generation step, which generates thermal image reading result information by matching the position information of the joint portion with the joint state of the joint portion.

[0064] More specifically, a predetermined contour is extracted from the captured thermal image. For example, during the charging and discharging of the battery cell 30, predetermined heat is generated from each of the battery cell 30, the busbar 40, and the wire W and transported to the surrounding area. Here, each of the battery cell 30, the busbar 40, and the wire W may have different predetermined dimensions, materials, and properties, and when viewed by capturing a thermal image of the battery cell 30, the busbar 40, and the wire W, a small temperature difference may occur at the boundaries between them, and a contour may be generated by this temperature difference.

[0065] Therefore, the shape of the junction between the battery cell 30 and the wire W can be generated by extracting a predetermined contour from the captured thermal image, and thus, the pixel corresponding to the junction of the wire W can be distinguished from other pixels. Therefore, the junction of the wire W in the captured thermal image can be known.

[0066] Next, the pixels of the captured thermal image P1 are classified based on temperature. That is, the pixels of the captured thermal image P1 are divided into pixels A1 and A2, which have a high temperature T2 above a predetermined reference temperature, and pixels with a low temperature T1 below the reference temperature. The high temperature T2 and the low temperature T1 can each have a predetermined temperature range. For example, the low temperature T1, which is below the reference temperature, can have a predetermined temperature range, and the high temperature T2 can have a predetermined temperature range greater than that of the low temperature T1.

[0067] For example, the reference temperature can be within the range of the surface temperature of the wire W when the battery cell 30 is charged or discharged in the state where the busbar 40, the wire W, and the normal wire connection of the battery cell 30 are engaged and connected. Here, the surface temperature can be obtained by theoretical calculation or by a predetermined experiment of repeatedly measuring the temperature of the wire W connected to the battery cell 30 while charging or discharging the battery cell 30 at room temperature or standard temperature.

[0068] Next, pixels A1 and A2 with high temperature T2 are distinguished from pixels with low temperature, and a closed curve (not shown) is formed to surround pixels A1 and A2 with high temperature T2. Then, it is checked whether the conductor W is located inside the closed curve. That is, it can be checked whether the contours of the pixels extracted from the thermal image P1 to distinguish the junction corresponding to the conductor W and other pixels overlap with the closed curve surrounding pixels A1 and A2 with high temperature T2. Then, when the contours overlap with the closed curve, it can be checked whether the conductor W is located inside the closed curve.

[0069] Subsequently, the positional information of the joint portion of the conductor W located inside the closed curve is obtained. For example, by utilizing the mounting height, mounting angle, viewing angle, and resolution XY of the thermal imaging unit 70, as well as the height and area of ​​the top surface of the battery pack B, the positional information of the joint portion of the conductor W located inside the closed curve can be obtained in the form of predetermined coordinates. In the same manner, the positional information of the joint portion of the conductor W located outside the closed curve can be obtained.

[0070] Subsequently, the joint of conductor W located inside the closed curve is determined to be an abnormal connection. Conversely, the joint of conductor W located outside the closed curve is determined to be a normal connection.

[0071] 1.5. Battery Pack Magnetic Field Image Capture Procedure S500

[0072] Figure 7 This is an exemplary schematic diagram illustrating the steps of capturing a magnetic field image of a battery pack according to an exemplary embodiment.

[0073] Reference Figure 7 The steps for capturing the magnetic field image of battery pack B are as follows:

[0074] When a current and a magnetic field are simultaneously applied to a target, the target's magnetization state can form a specific angle, and the magnitude of the magnetic field that generates the current can be measured through this angle. Furthermore, the intensity of reflected light generated as a laser beam is incident on the target can be detected, and the strength of the magnetic field can be calculated based on the detected intensity of the reflected light. Additionally, various magnetic sensors can be used to obtain the magnetic field strength, thereby generating a magnetic field image.

[0075] For example, a magnetic field image of the battery pack B can be captured using a magnetic field image capturing unit 80, which includes a predetermined arrangement of magnetic sensors. The steps for capturing a magnetic field image of the battery pack may include: placing the magnetic field image capturing unit 80 above the support 50; and capturing a magnetic field image of a predetermined plane on which wires W are disposed using the magnetic field image capturing unit 80.

[0076] For example, the magnetic field image capturing unit 80 can be disposed on the top surface of the battery pack B, and then a magnetic field image of the top surface of the battery pack B can be captured while scanning the top surface of the battery pack B in a horizontal direction. That is, the magnetic field image is generated by capturing the same predetermined plane as the one captured to obtain the thermal image. Here, the captured magnetic field image may have a predetermined pixel size determined with respect to the pixel size corresponding to the captured thermal image. Specifically, the magnetic field image may have the same pixel size as the thermal image.

[0077] The battery pack thermal imaging and battery pack magnetic field image capture steps described above can be performed simultaneously with the charging and discharging of individual battery cells. Furthermore, these two steps can be performed concurrently. Therefore, the thermal and magnetic field images can have the same shooting area and the same shooting time. Alternatively, the battery pack thermal imaging and battery pack magnetic field image capture steps can be performed in a predetermined order and with a predetermined time difference.

[0078] 1.6. Magnetic field image reading step S600

[0079] Figure 8 This is a conceptual diagram illustrating a magnetic field image reading step according to an exemplary embodiment.

[0080] Reference Figure 8 The magnetic field image reading step can read the connection status of the battery cell and the wire connection from the captured magnetic field image data DB2, and the judgment unit 80 performs the judgment.

[0081] The magnetic field image reading step may include: a magnetic field image contour generation step, which generates the shape of the joint portion of the battery cell 30 and the wire W in the captured magnetic field image by using the contour extracted from the thermal image reading step; a joint portion magnetic field strength reading step, which reads the magnetic field strength of the joint portion of the battery cell and the wire from the captured magnetic field image data DB2; a joint portion considered as a normal connection step, which determines the joint state of the joint portion as a normal connection state when the magnetic field strength of the joint portion of the battery cell and the wire is greater than a predetermined reference strength; a joint portion considered as an abnormal connection step, which determines the joint state of the joint portion as an abnormal connection state when the magnetic field strength of the joint portion of the battery cell and the wire is less than the reference strength; and a magnetic field image reading result information generation step, which generates magnetic field image reading result information by matching the position information of the joint portion with the joint state of the joint portion.

[0082] That is, the pixels of the magnetic field image P2 captured at a predetermined resolution XY can be distinguished by different colors or brightness according to the magnetic field strength, and are divided into pixels with magnetic field strengths corresponding to strengths m2 within a predetermined range greater than the reference strength, and pixels with magnetic field strengths corresponding to strengths m1 within a predetermined range less than the reference strength. Therefore, by using the contour extracted from the thermal imaging reading step, the shape of the junction of the battery cell 30 and the wire W is generated in the captured magnetic field image P2, and a closed curve (not shown) is generated around the pixels with magnetic field strengths greater than the reference strength. It is checked whether the junction of the wire W is located inside the closed curve, and the position information of the wire W inside the closed curve and the position information of the wire W outside the closed curve are obtained. The unit of magnetic field strength is microtesla (LTesla). The reference strength can be measured from the wire W while the battery cell 30 is being charged or discharged, in the state where the busbar 40, the wire W, and the battery cell 30 are normally connected and joined. Here, the reference strength can be obtained by theoretical calculation or by a predetermined experiment that repeatedly measures the magnetic field strength generated by the wire W connected to the battery cell 30 while charging or discharging the battery cell 30 at room temperature or standard temperature.

[0083] Then, the joint portion of the conductor W located inside the closed curve is determined to be a normal connection state, and the remaining portion is determined to be an abnormal connection state.

[0084] 1.7. Steps for determining defects in conductor bonding condition (S700)

[0085] The determination step of the wire bonding state defect is performed in the judgment unit 80, and the bonding state of the battery cell and the wire bonding part is finally determined by combining the thermal image reading result information obtained in the thermal image reading step and the magnetic field image reading result information obtained in the magnetic field image reading step.

[0086] Specifically, the steps for determining the defective bonding state of the conductor can be achieved by comparing the thermal image reading results and the magnetic field image reading results to ultimately determine the bonding state of the battery cell and the conductor as one of the following: normal connection state, abnormal connection state, and abnormal disconnection state.

[0087] That is, when the connection state of the joint between the battery cell and the wire is considered to be an abnormal connection state by comparing the thermal image reading results and the magnetic field image reading results, the connection state of the joint can be finally determined to be an abnormal connection state.

[0088] For example, the characteristic of an abnormal connection state at the junction of a battery cell and a wire indicates that the junction is at a high temperature. That is, when the junction is at a high temperature, the junction state is ultimately determined to be an abnormal connection state, regardless of the magnetic field image reading results.

[0089] In addition, when the connection status of the joint between the battery cell and the wire is considered to be in a normal connection state by comparing the thermal image reading results and the magnetic field image reading results, the connection status of the joint can be finally determined to be in a normal connection state.

[0090] For example, the characteristic of a junction between a battery cell and a wire being considered a normal connection indicates that the junction has a strong magnetic field. In this case, the junction's connection state is ultimately determined to be a normal connection, regardless of the thermal imaging readings.

[0091] In addition, when comparing the thermal image reading results and the magnetic field image reading results, if the connection status of the joint between the battery cell and the wire is considered as a normal connection or an abnormal connection, the connection status of the joint can be ultimately determined as an abnormal disconnection.

[0092] That is, when the junction between the battery cell and the wire is completely disconnected, the junction status cannot be confirmed by temperature difference or magnetic field image alone.

[0093] For example, a completely disconnected joint and a normally connected joint may not generate heat or may generate very little heat, and because their temperatures can be greatly affected, the two parts cannot be distinguished by temperature.

[0094] Furthermore, since each of the damaged joint and the completely broken joint has a small magnetic field strength, the two parts cannot be distinguished by the magnetic field strength.

[0095] However, according to an exemplary embodiment, the comparison of thermal image reading results and magnetic field image reading results to check the connection status of the battery cell and the wire connection is included in all states considered as normal connection states and states considered as abnormal connection states. That is, by cross-verifying the connection status in terms of thermal state and magnetic field strength, the connection status of the connection portion can be accurately determined as an abnormal disconnection state.

[0096] Although embodiments of the invention have been described, it should be understood that the invention is not limited to these embodiments. Therefore, the preferred embodiments should be considered descriptive rather than limiting, and the technical scope of the invention is not limited to these embodiments. Consequently, those skilled in the art will readily understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as defined by the appended claims.

[0097] (Explanation of reference numerals in the attached diagram)

[0098] 10: Battery pack casing

[0099] 20: Battery cell holder

[0100] 30: Battery cell

[0101] 40: Busbar

[0102] 50: Support section

[0103] 60: Thermal Imaging Unit

[0104] 70: Magnetic field imaging unit

[0105] 80: Judgment Department

[0106] H: Hole

[0107] W: Conductor

[0108] DB1: Thermal image data captured

[0109] DB2: Image data of the captured magnetic field

[0110] P1: Thermal image taken

[0111] P2: Image of the magnetic field taken

Claims

1. A battery pack identification method, comprising: The battery pack manufacturing process involves combining and connecting individual battery cells and wires to create the battery pack. The battery cell charging and discharging steps involve charging and discharging the battery cell through the wires. The thermal imaging process for the battery pack involves capturing thermal images of the battery pack while the individual battery cells are being charged and discharged. The thermal image reading step involves reading the bonding state of the junction between the battery cell and the wire from the captured thermal image data. The battery pack magnetic field image capturing step involves capturing the magnetic field image of the battery pack while the individual battery cells are being charged and discharged. The magnetic field image reading step involves reading the engagement state of the joint portion of the battery cell and the wire from the captured magnetic field image data. as well as The step of determining the bonding state defect of the conductor is to combine the thermal imaging reading results obtained in the thermal imaging reading step and the magnetic field image reading results obtained in the magnetic field image reading step to finally determine the bonding state of the battery cell and the conductor. The final determined engagement state is selected from normal connection state, abnormal connection state, and abnormal disconnection state, and The abnormal disconnection state is determined by comparing the thermal image reading results and the magnetic field image reading results.

2. The battery pack determination method according to claim 1, wherein, The battery pack thermal imaging step generates a thermal image by photographing a predetermined plane on which the wires are set, and The thermal image taken has a predetermined pixel size that is smaller than at least one of the thickness of the conductor and the size of the joint portion of the conductor.

3. The battery pack determination method according to claim 1, wherein, The thermal image reading steps include: The thermal image contour generation step involves extracting a predetermined contour from the captured thermal image and generating the shape of the junction portion of the battery cell and the wire. The temperature reading step of the joint portion involves reading the temperature of the joint portion between the battery cell and the wire from the captured thermal image data as either a high temperature or a low temperature. The step of determining whether a joint is an abnormal connection is to determine the joint state of the joint as an abnormal connection state when the temperature of the joint between the battery cell and the wire is higher than a predetermined reference temperature. The step of determining whether the joint is considered a normal connection involves determining the joint state as a normal connection state when the temperature of the joint between the battery cell and the wire is lower than the reference temperature; and The thermal image reading result information generation step generates the thermal image reading result information by matching the position information of the joint portion with the joint state of the joint portion.

4. The battery pack determination method according to claim 2, wherein, The battery pack magnetic field image capturing step generates a magnetic field image by capturing images of the same predetermined plane as those captured to obtain the thermal image, and The captured magnetic field image has a predetermined pixel size that corresponds to the pixel size of the captured thermal image.

5. The battery pack determination method according to claim 3, wherein, The magnetic field image reading steps include: The magnetic field image contour generation step generates the shape of the junction portion of the battery cell and the wire in the captured magnetic field image by using the contour extracted from the thermal image reading step. The magnetic field strength reading step of the joint portion involves reading the magnetic field strength of the joint portion of the battery cell and the wire from the captured magnetic field image data. The step of determining that the joint portion is considered to be a normal connection is as follows: when the magnetic field strength of the joint portion of the battery cell and the wire is greater than a predetermined reference strength, the joint state of the joint portion is determined to be considered to be a normal connection state. The step of determining whether a joint is considered an abnormal connection involves determining the joint state as an abnormal connection state when the magnetic field strength at the joint between the battery cell and the wire is less than the reference strength; and The magnetic field image reading result information generation step generates the magnetic field image reading result information by matching the position information of the joint portion with the joint state of the joint portion.

6. The battery pack determination method according to claim 5, wherein, The step of determining the defect in the wire connection state is to compare the thermal image reading results and the magnetic field image reading results to finally determine the connection state of the connection portion of the battery cell and the wire as one of the following: normal connection state, abnormal connection state, and abnormal disconnection state.

7. The battery pack determination method according to claim 6, wherein, By comparing the thermal image reading results and the magnetic field image reading results, the steps for determining the wire bonding state defect are finally determined: When the connection state of the joint portion of the battery cell and the wire is considered to be an abnormal connection state, the connection state of the joint portion is determined to be the abnormal connection state. When the connection state of the joint portion of the battery cell and the wire is considered to be a normal connection state, the connection state of the joint portion is determined to be the normal connection state. When the connection state of the joint portion of the battery cell and the wire is either considered a normal connection state or a considered abnormal connection state, the connection state of the joint portion is determined to be an abnormal disconnection state.

8. The battery pack determination method according to claim 1, wherein, While performing the charging and discharging steps of the individual battery cells, the thermal imaging step of the battery pack and the magnetic field image capture step of the battery pack are also performed simultaneously.

9. The battery pack determination method according to claim 1, wherein, While the individual battery cells are being charged and discharged, thermal imaging of the battery pack and magnetic field imaging of the battery pack are performed in a predetermined sequence and at predetermined time differences.

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