System for detecting defects of electrode tabs and method for detecting defects of electrode tabs using the same

Abstract

The present technology relates to a system for detecting defects of an electrode tab, which can easily detect whether an electrode tab is folded during a manufacturing process of a secondary battery, and a method for detecting defects of the electrode tab using the system.

Description

Technical Field

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2021-0020860, filed on February 17, 2021, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] The present invention relates to a system for detecting defects of an electrode tab and a method for detecting defects of an electrode tab using the system. Background Art

[0003] Secondary batteries, which can be charged and discharged, are widely used as energy sources or auxiliary power supplies for wireless mobile devices. They are also attracting attention as energy sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), aiming to address air pollution caused by existing gasoline and diesel vehicles that use fossil fuels.

[0004] Representatively, in terms of battery shape, there is a great demand for prismatic secondary batteries and pouch-type secondary batteries that are thin and can be applied to products such as mobile phones, while in terms of battery materials, there is a great demand for lithium secondary batteries such as lithium-ion batteries and lithium-ion polymer batteries that have advantages such as high energy density, discharge voltage, and output stability.

[0005] Secondary batteries are classified according to the structural type of the electrode assembly having a positive electrode / separator / negative electrode structure. Representatively, secondary batteries may include: a jelly roll (wound) type electrode assembly having a structure in which a long sheet of positive and negative electrodes are wound with a separator interposed between them; a stacked (stacked) type electrode assembly having a structure in which a plurality of positive and negative electrodes cut in units of predetermined sizes are sequentially stacked with a separator interposed between them; and a stacked / folded type electrode assembly having a structure in which a bi-cell or full cell is wound, in which the positive and negative electrodes are stacked in a specified unit with a separator interposed between them, etc.

[0006] Therefore, after each manufacturing process operation is performed and / or after the finished product is manufactured, the secondary battery should be thoroughly inspected. Inspection is one of the most important processes in the secondary battery production process and is important in quality control to check whether the required performance and stability are provided. Here, the purpose of quality control is to produce good products and filter out defective products by determining whether the secondary battery has appropriate charge / discharge performance. When this quality control is performed well, high-quality secondary batteries can be produced.

[0007] Figure 1 is an exploded perspective view schematically illustrating a general structure of a single cell. Figure 2 It is a schematic diagram Figure 1 A three-dimensional diagram of the stacked structure, and Figure 3 is a view exemplarily illustrating a phenomenon in which electrode tabs of a single cell are folded.

[0008] refer to Figure 1 and Figure 2 The single cell 1 has a structure in which a positive electrode 2 and a negative electrode 3 are sequentially stacked with a separator 4 interposed therebetween. The positive electrode 2 has a positive electrode active material applied to both surfaces of a positive electrode current collector, and the negative electrode 3 has a negative electrode active material applied to both surfaces of a negative electrode current collector. Furthermore, positive and negative electrode tabs 2-1 and 3-1, which are not coated with active material and are electrically connected to the positive and negative electrode leads that constitute the electrode terminals of the battery, are formed so as to protrude from the ends of the positive and negative electrode current collectors.

[0009] The positive electrode tab 2-1 and the negative electrode tab 3-1 are made of foil material, so the electrode tabs may be folded during the manufacturing process of the secondary battery. When such electrode tab folding occurs, the capacity of the secondary battery is reduced or an internal short circuit is caused.

[0010] In addition, during the manufacturing process of the secondary battery, the single cell 1 is transferred to the loading part using the jig 5. Figure 3 As shown, a clamp 5 holds a cell 1 and transfers it to the loading area. During this process, when the electrode tabs 2-1 and 3-1 of the cell 1 are lifted, the clamp 5 interferes with the cell 1, causing the tabs to fold. Since the cell 1 is covered by the clamp 5 while being held, it is impossible to inspect whether the tabs are folded.

[0011] In particular, in a structure in which the single cells 1 are stacked, it is impossible to check from the outside whether the electrode tabs are folded between the single cells 1 . Summary of the Invention

[0012] Technical issues

[0013] An object of the present invention is to solve the above problems and provide a system for detecting defects of electrode tabs that can easily detect whether an electrode tab is folded during a manufacturing process of a secondary battery, and a method for detecting defects of an electrode tab using the system.

[0014] Technical Solution

[0015] The present invention provides a system for detecting defects in electrode tabs. In one example, the system for detecting defects in electrode tabs according to the present invention includes: a gripper configured to suck a unit battery including an electrode and transfer the unit battery to a cartridge, wherein the gripper has an exposed area formed so that a portion of an area of ​​the electrode tab facing the electrode is exposed; and a visual inspection unit configured to check whether the electrode tab is detected in the exposed area of ​​the gripper when the unit battery is sucked.

[0016] In another example, the system for detecting defects in electrode tabs according to the present invention may further include a data processing unit configured to determine whether the electrode tab is defective based on whether the electrode tab is detected by the visual inspection unit. In a specific example, when the electrode tab is not detected in the exposed area of ​​the jig, the data processing unit may determine that the electrode tab is defective due to being folded. In addition, when the electrode tab is detected in the exposed area of ​​the jig, the data processing unit may determine that the electrode tab is normal.

[0017] In one example, in the system for detecting defects of an electrode tab, the exposed area of ​​the jig may be formed in the shape of one or more cutouts at a portion overlapping with the electrode tab of the unit battery adsorbed to the jig.

[0018] In addition, the jig may further include a suction unit that suctions the unit battery using vacuum.

[0019] In one example, the visual inspection unit may include: a camera configured to capture an image of the unit cell sucked by the jig; and an illumination device configured to illuminate the unit cell with light for imaging.

[0020] In addition, the unit cell may be a mono-cell or a half-cell.

[0021] The present invention also relates to a method for detecting electrode tab defects using the above-described system for detecting electrode tab defects. In one example, the method for detecting electrode tab defects according to the present invention includes the following steps: using a jig having an exposed area to absorb a unit battery including an electrode, the exposed area being formed so that a portion of the electrode tab facing the electrode is exposed; and inspecting, using a visual inspection unit, whether the electrode tab is detected in the exposed area of ​​the jig when the unit battery is absorbed.

[0022] In another example, the method of detecting a defect of an electrode tab according to the present invention may further include determining whether the electrode tab is defective according to whether the electrode tab is detected in the exposed area of ​​the jig.

[0023] In a specific example, determining whether the electrode tab is defective may include determining that the electrode tab is defective due to being folded when checking that the electrode tab is not detected in the exposed area of ​​the jig.

[0024] Furthermore, determining whether the electrode tab is defective may include determining that the electrode tab is normal when checking that the electrode tab is detected in the exposed region of the jig.

[0025] Beneficial effects

[0026] According to the system for detecting a defect of an electrode tab and the method of detecting a defect of an electrode tab using the same of the present invention, it is possible to easily detect whether an electrode tab is folded during a manufacturing process of a secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an exploded perspective view schematically illustrating a general structure of a single cell.

[0028] Figure 2 It is a schematic diagram Figure 1 A three-dimensional diagram of the stacking structure.

[0029] Figure 3 is a view exemplarily illustrating a phenomenon in which electrode tabs of a single cell are folded.

[0030] Figure 4 FIG. 1 is a schematic diagram of a system for detecting defects of an electrode tab according to an embodiment of the present invention.

[0031] Figure 5 It is shown in the figure Figure 4 Schematic diagram of a process for detecting defects of an electrode tab in area A of FIG.

[0032] Figure 6 is a view showing a photograph taken by a visual inspection unit when a unit battery is sucked by a jig in the system for detecting defects of an electrode tab according to the present invention.

[0033] Figure 7 is a schematic diagram illustrating a system for detecting defects of an electrode tab according to another embodiment of the present invention.

[0034] Figure 8 is a flowchart illustrating a method of detecting defects of an electrode tab according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The terms and words used in this specification and claims should not be interpreted as being limited to the common meanings or dictionary meanings, but should be interpreted with meanings and concepts consistent with the technical scope of the present invention based on the concept of the inventor to appropriately define the terms in order to best describe the principle of the present invention.

[0036] The present invention relates to a system for detecting defects of an electrode tab and a method for detecting defects of an electrode tab using the system.

[0037] Typically, during the manufacturing process of secondary batteries, a jig is used to transport the cells to the loading area. The jig absorbs the cells and transports them to the loading area. During this process, when the electrode tabs of the cells are lifted, the electrode tabs can fold due to interference from the jig. In this case, the cells are covered by the jig when they are absorbed, making it impossible to inspect whether the electrode tabs are folded. In particular, in a stacked structure, it is impossible to externally inspect the electrode tabs that have folded between the cells.

[0038] Therefore, the present invention provides a system for detecting electrode tab defects that can easily detect whether an electrode tab is folded during a secondary battery manufacturing process, and a method for detecting electrode tab defects using the system. Specifically, according to the system for detecting electrode tab defects and the method for detecting electrode tab defects using the system of the present invention, when a jig sucks a unit battery including an electrode, it is possible to easily detect whether the electrode tab is defective by checking whether the electrode tab is detected in an exposed area of ​​the jig.

[0039] In the present invention, the term "unit cell including electrodes" may refer to a single cell in which a first electrode, a separator, and a second electrode are stacked in sequence, or a single cell (mono-cell) in which a separator, a first electrode, a separator, and a second electrode are stacked in sequence, and may refer to a half-cell in which a separator, a first electrode, and a separator are stacked in sequence, or a half-cell in which a separator, a second electrode, and a separator are stacked in sequence. In addition, the first electrode may be a positive electrode or a negative electrode, and the second electrode may be an electrode having a different polarity from that of the first electrode. For example, the unit cell may be a single cell in which a separator, a first electrode (negative electrode), a separator, and a second electrode (positive electrode) are stacked in sequence, and the first electrode and the second electrode may have a structure in which electrode tabs are formed at opposite ends to extend from the ends.

[0040] Method of invention

[0041] Hereinafter, a system for detecting defects of an electrode tab and a method for detecting defects of an electrode tab using the same according to the present invention will be described in detail with reference to the accompanying drawings.

[0042] <First embodiment>

[0043] Figure 4 is a schematic diagram of a system for detecting defects of an electrode tab according to an embodiment of the present invention, and Figure 5 It is shown in the figure Figure 4 Schematic diagram of a process for detecting defects of an electrode tab in area A of FIG.

[0044] refer to Figure 4 and Figure 5 The system 100 for detecting defects of an electrode tab according to the present invention includes: a gripper 110 that sucks a unit cell 10 including an electrode and transfers the unit cell 10 to a box (not shown), wherein the gripper 110 has an exposed area 111 through which a portion of the electrode tab 11 facing the exposed area 111 is exposed; and a visual inspection unit 120 that checks whether the electrode tab 11 is detected in the exposed area 111 of the gripper 110 when the unit cell 10 is sucked. In a specific example, the system 100 for detecting defects of an electrode tab according to the present invention can easily check whether the electrode tab 11 is defective by checking whether the electrode tab 11 is detected in the exposed area 111 of the gripper 110 when the unit cell 10 including an electrode is sucked.

[0045] First, the fixture 110 is used to transfer the unit cell 10 to the box, and can be a fixture 110 that transfers the single cell to the loading part in a typical secondary battery stacking process. The fixture 110 can have various structures and shapes. In addition, the fixture 110 may include an adsorption unit (not shown) that utilizes vacuum adsorption of the unit cell 10. For example, a plurality of adsorption units may be provided and these adsorption units may adsorb multiple areas of the upper surface of the unit cell 10. In addition, any adsorption unit that allows the unit cell 10 to be adsorbed to the fixture 110 using vacuum may be used as an adsorption unit without limitation. In addition, the box may be a loading part for loading the unit cell 10 to manufacture an electrode assembly, and may be a typical box for stacking batteries.

[0046] In one example, an exposed area 111 is formed in the jig 110. Specifically, the exposed area 111 is used to inspect the electrode tabs 11 of the electrodes of the unit cells 10 for defects and is formed in a portion of the jig 110 facing the electrode tabs 11. In the accompanying drawings, the exposed area 111 is illustrated as only a portion of the jig 110 facing the first electrode tab 11, but the present invention is not limited thereto. The exposed area 111 may be formed in the entire jig 110 facing the first electrode tab 11.

[0047] Any area of ​​the jig 110 facing the electrode tab 11 may be used as the exposed area 111 without limitation. In one example, the exposed area 111 of the jig 110 may be formed in the shape of one or more cutouts at portions overlapping the electrode tab 11 of the unit battery 10 adsorbed to the jig 110. The cutouts may be formed to be curved in the longitudinal direction of the jig 110 and may be formed symmetrically with each other in the longitudinal direction of the jig 110.

[0048] In the drawings, the exposed area 111 of the clamp 110 is illustrated as being bent to have a cutout shape, but the exposed area 111 of the clamp 110 may have a typical hole shape instead of a cutout shape. Any area formed to be exposed in an area facing the electrode tab 11 may be used as the exposed area 111 of the clamp 110 without limitation.

[0049] Furthermore, in the system 100 for detecting defects in electrode tabs according to the present invention, the visual inspection unit 120 can perform an alignment visual inspection while the jig 110 is adsorbing the unit battery 10. In a specific example, when the visual inspection unit 120 performs the alignment visual inspection, it can be checked whether the electrode tab 11 is defective based on whether the electrode tab 11 is detected in the exposed area 111 of the jig 110.

[0050] In one example, the visual inspection unit 120 may be used to inspect the outer dimensions of the unit cell 10 and includes a camera (not shown) that captures an image of the unit cell 10 adsorbed by the jig 110 and an illumination device (not shown) that illuminates the unit cell 10 with light for imaging.

[0051] In a specific example, when the unit cell 10 is adsorbed by the fixture 110, a charge-coupled device (CCD) camera located above and below the unit cell 10 can photograph the unit cell 10 to measure the outer dimensions of the unit cell, while a pair of lighting devices located above and below the unit cell 10 emit light. In addition, any lighting device having a light source that helps the camera accurately measure the outer dimensions of the unit cell 10 can be used as the lighting device without limitation, and the lighting device can be, for example, a light-emitting diode (LED) lighting device. However, in the related art, for position correction, when the unit cell 10 is loaded, the position of the unit cell 10 is corrected by measuring the dimensions of 8 points, while in the present invention, in addition to the existing 8 points, the dimensions of the position facing the electrode tab 11 can also be additionally measured.

[0052] That is, the system 100 for detecting defects of electrode tabs according to the present invention can easily check whether the electrode tab 11 is defective by checking whether the electrode tab 11 is detected in the exposed area of ​​the jig 110 when the unit battery 10 is sucked.

[0053] Figure 6 1 is a view showing a photograph taken by a visual inspection unit when a unit battery 10 is adsorbed to a jig 110 in a system for detecting defects of an electrode tab according to the present invention. Figure 6 , it can be confirmed that when the unit battery 10 is adsorbed by the jig 110 , the electrode tab 11 is detected in the exposed area 111 of the jig 110 .

[0054] <Second embodiment>

[0055] Figure 7 is a schematic diagram illustrating a system for detecting defects of an electrode tab according to another embodiment of the present invention.

[0056] refer to Figure 7 , a system 200 for detecting defects of an electrode tab according to the present invention includes: a jig 210 that absorbs a unit cell 20 including an electrode and transfers the unit cell 20 to a magazine, wherein the jig 210 has an exposed area 211 formed so that a portion of an area of ​​the electrode tab 21 facing the electrode is exposed; and a visual inspection unit 220 that checks whether the electrode tab 21 is detected in the exposed area 211 of the jig 210 when the unit cell 20 is absorbed.

[0057] In addition, the system 200 for detecting defects of an electrode tab according to the present invention further includes a data processing unit 230 that determines whether the electrode tab is defective according to whether the electrode tab 21 is detected by the visual inspection unit 220 .

[0058] In a specific example, the data processing unit 230 may use the data obtained by the camera of the visual inspection unit 220 to check whether the electrode tab 21 is detected in the exposed area 211 of the jig 210 to determine whether the electrode tab 21 is defective. In addition, the data processing unit 230 may compare the data with previously stored reference data to check whether the data has a deviation value greater than or equal to a threshold value.

[0059] In a specific example, when it is checked that the electrode tab 21 is not detected in the exposed area 211 of the jig 210, the data processing unit 230 can determine that the electrode tab 21 is defective due to being folded. In addition, when it is checked that the electrode tab 21 is detected in the exposed area 211 of the jig 210, the data processing unit 230 can determine that the electrode tab 21 is normal. In addition, the corresponding unit cell 20 is classified as normal or defective according to the determination value determined by the data processing unit 230. In addition, the unit cell 20 classified as normal can be transferred to the cartridge and can be manufactured as a secondary battery according to the secondary battery manufacturing process, and the unit cell classified as defective can be discarded.

[0060] In addition, a storage unit may be further included for additionally storing the determination value determined by the data processing unit 230. In a specific example, the storage unit may receive and store the image captured by the visual inspection unit 220 and the determination value.

[0061] <Third embodiment>

[0062] Figure 8 is a flow chart illustrating a method of detecting defects of an electrode tab according to an embodiment of the present invention. Figure 8 , a method for detecting defects of an electrode tab according to the present invention includes: operation S10 of sucking a unit battery including an electrode using a jig having an exposed area formed so that a portion of an area of ​​the electrode tab facing the electrode is exposed; and operation S20 of checking, by a visual inspection unit, whether the electrode tab is detected in the exposed area of ​​the jig when the unit battery is sucked.

[0063] The method for detecting defects in electrode tabs according to the present invention can be performed during a process of attaching a unit cell including an electrode and transferring the unit cell to a magazine, or during a process of attaching the unit cell using a jig. Specifically, in the method for detecting defects in electrode tabs according to the present invention, a jig having the aforementioned exposed area formed therein is used during the process of attaching the unit cell and transferring the unit cell to a magazine. The jig is positioned so as to face the unit cell when attaching the unit cell, and has an exposed area formed so as to expose a portion of the area of ​​the electrode tab facing the electrode.

[0064] In a specific example, the visual inspection unit can perform an alignment visual inspection in a state where the jig absorbs the unit battery. In addition, when the visual inspection unit performs the alignment visual inspection, it can check whether the electrode tab is defective based on whether the electrode tab is detected in the exposed area of ​​the jig.

[0065] The method of detecting a defect of an electrode tab according to the present invention is performed using the above-described system for detecting a defect of an electrode tab, and a description of the configuration of the system for detecting a defect of an electrode tab will be omitted.

[0066] In addition, the method of detecting a defect of an electrode tab according to the present invention further includes determining whether the electrode tab is defective according to whether the electrode tab is detected in the exposed region of the jig.

[0067] In a specific example, determining whether the electrode tab is defective may include determining whether the electrode tab is defective by checking whether the electrode tab is detected in the exposed area of ​​the fixture using data obtained by a camera of the visual inspection unit. In addition, the data processing unit may compare the data with previously stored reference data to check whether the data has a deviation value greater than or equal to a threshold value.

[0068] That is, determining whether the electrode tab is defective may include determining that the electrode tab is defective due to being folded when the electrode tab is not detected in the exposed area of ​​the jig. In addition, determining whether the electrode tab is defective may include determining that the electrode tab is normal when the electrode tab is detected in the exposed area of ​​the jig.

[0069] In addition, when determining whether the electrode tab is defective, the corresponding unit cell is classified as normal or defective based on the image information of the unit cell captured by the visual inspection unit, and the unit cell determined to be defective is discarded.

[0070] Furthermore, the unit cells determined to be normal by the method of detecting defects of electrode tabs of the present invention may be manufactured as battery cells by performing an additional process after stacking the unit cells on the cartridge as described above.

[0071] In particular, the battery cells manufactured after performing the method of detecting electrode tab defects of the present invention may be pouch-type battery cells. The battery cells are pouch-type cells and may have a structure in which an electrode assembly having a positive electrode / separator / negative electrode structure is embedded in an external laminate sheet, with the electrode assembly connected to electrode leads formed outside the external material. In a specific example, the battery cells may be pouch-type cells with electrode leads protruding outward from the sheet and extending in opposite directions.

[0072] The present invention has been described in detail with reference to the accompanying drawings and embodiments. However, since the embodiments described in this specification and the configurations shown in the drawings are merely exemplary embodiments and do not represent the entire technical scope of the present invention, it should be understood that the present invention encompasses various equivalents and modifications at the time of filing this application.

[0073] [Reference Number]

[0074] 1: Single battery

[0075] 2: Positive electrode

[0076] 2-1: Positive terminal

[0077] 3: Negative electrode

[0078] 3-1: Negative terminal

[0079] 4: Diaphragm

[0080] 5: Fixture

[0081] 10, 20: Lamination

[0082] 11, 21: electrode tabs

[0083] 100, 200: System for detecting defects in electrode tabs

[0084] 110, 210: fixture

[0085] 111, 211: Exposed areas

[0086] 120, 220: Visual inspection unit

[0087] 230: Data processing unit.

Claims

1. A system for detecting defects in an electrode tab, the system comprising: a jig configured to suck a unit battery including an electrode and transfer the unit battery to a cartridge, wherein the jig has an exposed area formed such that a portion of an area facing an electrode tab of the electrode is exposed; a visual inspection unit configured to check whether an electrode tab is detected in an exposed area of ​​the jig when the unit battery is sucked; and a data processing unit configured to determine whether the electrode tab is defective based on whether the electrode tab is detected by the visual inspection unit; When it is checked that the electrode tab is not detected in the exposed area of ​​the jig, the data processing unit determines that the electrode tab is defective due to being folded. 2 . The system according to claim 1 , wherein when checking that the electrode tab is detected in the exposed area of ​​the jig, the data processing unit determines that the electrode tab is normal. 3 . The system according to claim 1 , wherein the exposed area of ​​the jig is formed in the shape of one or more cutouts at a portion overlapping with the electrode tabs of the unit battery adsorbed to the jig. 4 . The system according to claim 1 , wherein the jig further comprises a suction unit that suctions the unit battery using vacuum.

5. The system of claim 1 , wherein the visual inspection unit comprises: a camera configured to capture an image of the unit battery attracted by the clamp; and An illumination device is configured to illuminate the unit cell with light for imaging. The system according to claim 1 , wherein the unit cell including the electrode is a single cell or a half cell.

7. A method for detecting defects in an electrode tab, the method comprising the following steps: sucking a unit battery including an electrode using a jig having an exposed area formed so that a portion of an area facing an electrode tab of the electrode is exposed; checking, by a visual inspection unit, whether the electrode tab is detected in the exposed area of ​​the jig when the unit battery is adsorbed; and determining whether the electrode tab is defective based on whether the electrode tab is detected in the exposed area of ​​the jig, The determining whether the electrode tab is defective includes: when it is checked that the electrode tab is not detected in the exposed area of ​​the jig, determining that the electrode tab is defective due to being folded.

8. The method of claim 7, wherein determining whether the electrode tab is defective comprises: When it is checked that the electrode tab is detected in the exposed area of ​​the jig, it is determined that the electrode tab is normal.

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