Apparatus and method for inspecting electrode tab

Abstract

An apparatus for inspecting an electrode tab, according to an embodiment of the present invention, may inspect an electrode tab notched on one side, in the width direction, of an electrode sheet. The apparatus for inspecting an electrode tab may include: a detection unit configured to detect an incident laser beam; a laser generation unit configured to emit a laser beam toward the detection unit; and a controller configured to determine whether an electrode tab is defective, on the basis of the result of detection performed by the detection unit when the electrode tab passes by the position where a laser beam incident on the detection unit is blocked.

Description

Electrode tab inspection device and inspection method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0125111, filed September 19, 2023, and Korean Patent Application No. 10-2024-0126725, filed September 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to an inspection device and an inspection method for an electrode tab formed by notching on an electrode sheet.

[0005] Common types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. These batteries are used in small products such as digital cameras, DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, as well as in larger products requiring high output, such as electric and hybrid vehicles, as well as power storage devices that store surplus power or renewable energy, and as backup power storage devices.

[0006] To manufacture an electrode assembly, electrodes and a separator are manufactured and laminated. The electrode can be manufactured by applying a slurry-type electrode active material to a foil-type current collector.

[0007] Specifically, a cathode can be manufactured by applying a cathode active material slurry to a cathode current collector, and an anode can be manufactured by applying a cathode active material slurry to a cathode current collector. Then, when a separator is interposed between the manufactured cathode and anode and they are laminated, unit cells are formed, and when the unit cells are laminated to each other, an electrode assembly is formed. Then, when this electrode assembly is accommodated in a specific case and an electrolyte is injected, a secondary battery is manufactured.

[0008] Meanwhile, the electrode manufacturing process is divided into an active material mixing process, an electrode coating process, a rolling process, a notching process, and a cutting process. Among these, the notching process is a process in which an electrode tab is formed by notching a non-coated portion formed on one side of an electrode current collector. In addition, the cutting process is a process in which a unit electrode is formed by cutting an electrode sheet with an electrode tab notched into a certain length.

[0009] However, in the process of notching the electrode tab, defects such as the electrode tab being torn or part of it falling off may occur due to a deterioration in the quality of the electrode current collector, and such defects may be called tab torn.

[0010] Previously, during the lamination process of the above-mentioned unit electrodes onto a separator sheet, a vision camera was used to inspect the tab tone. However, this inspection method was somewhat unreliable, and in particular, it was difficult to properly detect when only the middle portion of the electrode tab was torn.

[0011] The problem to be solved by the present invention is to provide an electrode tab inspection device and inspection method capable of reliably inspecting a defective electrode tab in which a tap tone has occurred.

[0012] An electrode tab inspection device according to an embodiment of the present invention can inspect an electrode tab notched on one side in the width direction of an electrode sheet. The electrode tab inspection device may include a detection unit configured to detect an incident laser beam; a laser generation unit configured to emit a laser beam toward the detection unit; and a controller that determines whether the electrode tab is defective based on a result detected by the detection unit when the electrode tab passes a position where the laser beam incident on the detection unit is blocked.

[0013] The controller can determine that the electrode tab is defective when the laser beam is detected by the detection unit when the electrode tab passes a position where the laser beam is blocked.

[0014] The laser generation unit and the detection unit may be positioned facing each other with a path through which the electrode tab passes between them. The controller may determine whether the electrode tab is defective based on a result detected by the detection unit when the electrode tab passes between the laser generation unit and the detection unit.

[0015] The above laser generating unit may be configured such that the cross-sectional shape of the laser beam has a shape corresponding to the electrode tab.

[0016] The above laser generating unit may be configured so that the laser beam is incident perpendicularly to one surface of the electrode tab when the electrode tab passes a position where the laser beam is blocked.

[0017] The above laser generating unit may be configured to emit a laser beam toward the detection unit when the electrode tab passes a position where the laser beam is blocked.

[0018] The above electrode tab inspection device may further include a marking unit for marking an electrode tab that has been determined to be defective so as to be identifiable.

[0019] The above marking portion may be configured to mark a portion corresponding to an electrode tab determined to be defective among the electrode sheets.

[0020] The above laser generating unit may be configured so that the area on which the laser beam is projected onto the electrode tab is 50% to 99% of the area of ​​the electrode tab.

[0021] A method for inspecting an electrode tab according to an embodiment of the present invention can inspect an electrode tab notched on one side of an electrode sheet in the width direction. The method for inspecting an electrode tab can include a step of a laser generating unit emitting a laser beam toward a detection unit when the electrode tab passes a position that blocks a laser beam incident on a detection unit; and a step of determining whether the electrode tab is defective based on a result detected by the detection unit.

[0022] In the step of determining whether the electrode tab is defective, if the laser beam is detected by the detection unit, the electrode tab can be determined to be defective.

[0023] The above electrode tab inspection method may further include a step of marking an electrode tab that has been determined to be defective so as to be identifiable.

[0024] In the above marking step, a portion corresponding to an electrode tab judged to be defective among the electrode sheets may be marked.

[0025] In the step of emitting the laser beam, the area on which the laser beam is projected onto the electrode tab may be 50% to 99% of the area of ​​the electrode tab.

[0026] According to a preferred embodiment of the present invention, compared to the conventional technique of inspecting an electrode tab using a vision device such as a camera, even if the middle part of the electrode tab is torn and micro-cracks occur, a defect in the electrode tab can be reliably detected.

[0027] Additionally, the location where the electrode tab is torn and the size of the crack can be precisely detected.

[0028] In addition, in a subsequent process, unit electrodes including defective electrode tabs can be recovered in advance to prevent them from being used in the manufacture of battery cells, thereby improving the quality of battery cells.

[0029] In addition, the configurations according to preferred embodiments of the present invention may include effects that can be easily predicted by those skilled in the art.

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0031] Figure 1 is a schematic diagram of an electrode tab inspection device according to one embodiment of the present invention.

[0032] Figure 2 is a control block diagram of an electrode tab inspection device according to one embodiment of the present invention.

[0033] Fig. 3a is a drawing of an electrode tab with a torn outer portion as seen from above, and Fig. 3b is a side view showing a process of determining whether the electrode tab shown in Fig. 3a is defective.

[0034] Fig. 4a is a drawing of an electrode tab with a torn middle portion as seen from above, and Fig. 4b is a side view showing a process of determining whether the electrode tab shown in Fig. 4a is defective.

[0035] Figure 5 is a flowchart of an electrode tab inspection method according to another embodiment of the present invention.

[0036] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0037] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0038] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0039] FIG. 1 is a schematic diagram of an electrode tab inspection device according to an embodiment of the present invention, FIG. 2 is a control block diagram of an electrode tab inspection device according to an embodiment of the present invention, FIG. 3a is a drawing of an electrode tab with an outer portion torn as seen from above, FIG. 3b is a side view illustrating a process of determining whether the electrode tab illustrated in FIG. 3a is defective, FIG. 4a is a drawing of an electrode tab with a middle portion torn as seen from above, and FIG. 4b is a side view illustrating a process of determining whether the electrode tab illustrated in FIG. 4a is defective.

[0040] An electrode tab inspection device (hereinafter, “inspection device”) according to one embodiment of the present invention can inspect an electrode tab (2) notched on one side in the width direction of an electrode sheet (1). More specifically, the electrode sheet (1) can include a current collector in the form of a metal foil and an electrode active material layer applied to the current collector. The width of the electrode active material layer can be formed narrower than the width of the current collector. Accordingly, a part of the width direction of the current collector can form a non-coated portion on which the electrode active material layer is not applied. A plurality of electrode tabs (2) can be formed by notching the non-coated portion of the electrode sheet (1) at preset intervals. The electrode sheet (1) can move in the length direction. The inspection device can be configured to inspect the electrode tabs (2) of the moving electrode sheet (1).

[0041] In more detail, the inspection device may include a laser generating unit (10) configured to emit a laser beam (B), a detection unit (20) configured to detect the laser beam (B) emitted from the laser generating unit (10), and a controller (40) that determines whether the electrode tab (2) is defective based on the result detected by the detection unit (20).

[0042] The laser generating unit (10) can emit a laser beam (B) toward the detection unit (20). More specifically, the laser generating unit (10) and the detection unit (20) can be arranged to face each other with a path through which the electrode tab (2) passes between them. However, this is not limited to this, and the laser beam (B) emitted from the laser generating unit (10) can also have its path changed by an optical component such as a mirror and be incident on the detection unit (20). Hereinafter, a case where the laser generating unit (10) and the detection unit (20) face each other will be described as an example.

[0043] The detection unit (20) may include a detection plate arranged parallel to the electrode sheet (1) and facing the laser generation unit (10).

[0044] A plurality of electrode tabs (2) can sequentially pass between the laser generation unit (10) and the detection unit (20). For example, the laser generation unit (10) can be located above the path through which the electrode tabs (2) pass, and the detection unit (20) can be located below the path.

[0045] When the electrode tab (2) passes the position where the laser beam (B) is blocked, the laser beam (B) may not be detected by the detection unit (20). This is because the laser beam (B) emitted from the laser generation unit (10) is blocked by the electrode tab (2) and does not enter the detection unit (20). When the electrode tab (2) passes the position where the laser beam (B) is blocked may mean the point in time when the electrode tab (2) passes between the laser generation unit (10) and the detection unit (20).

[0046] The controller (40) may include at least one processor. The controller (40) may be electrically connected to the detection unit (20). The controller (40) may determine whether the electrode tab (2) is defective based on the result detected by the detection unit (20) when the electrode tab (2) passes a position where the electrode tab (2) blocks the laser beam (B). That is, the controller (40) may determine whether the electrode tab (2) is defective based on the result detected by the detection unit (20) when the electrode tab (2) passes between the laser generation unit (10) and the detection unit (20).

[0047] In more detail, the controller (40) can determine that the electrode tab (2) is defective when the detection unit (20) detects the laser beam (B) as it passes the position where the electrode tab (2) blocks the laser beam (B).

[0048] A normal electrode tab (2) can block the laser beam (B) when it passes between the laser generating unit (10) and the detection unit (20). Therefore, the laser beam (B) is not detected by the detection unit (20), and the controller (40) can determine that the electrode tab (2) is normal.

[0049] On the other hand, referring to FIGS. 3a and 3b, when the electrode tab (2f) with the outer portion torn passes between the laser generating unit (10) and the detection unit (20), the laser beam (B) is not completely blocked by the torn portion of the electrode tab (2f). That is, a part of the laser beam (B) may pass through the torn outer portion of the electrode tab (2f) and be incident on the detection unit (20). Therefore, the detection unit (20) detects the laser beam (B), and the controller (40) can determine that the electrode tab (2) is defective.

[0050] Referring to FIGS. 4a and 4b, when the electrode tab (2f) with its middle portion torn passes between the laser generating unit (10) and the detection unit (20), the laser beam (B) is not completely blocked by the torn portion of the electrode tab (2f). That is, a portion of the laser beam (B) may pass through the torn middle portion of the electrode tab (2f) and be incident on the detection unit (20). Therefore, the detection unit (20) detects the laser beam (B), and the controller (40) can determine that the electrode tab (2) is defective.

[0051] In particular, when the middle part of the electrode tab (2f) is torn and micro-cracks occur, conventional vision cameras have the problem of low detection reliability, but the inspection device according to the present invention can reliably detect defects in the electrode tab (2f). In addition, the inspection device according to the present invention has the advantage of being able to precisely detect the location where the electrode tab (2f) is torn and the size of the crack.

[0052] Meanwhile, the laser generating unit (10) can be configured so that the laser beam (B) is incident perpendicularly on one surface (e.g., the upper surface) of the electrode tab (2) when the electrode tab (2) passes a position where the laser beam (B) is blocked.

[0053] The beam cross-section of the laser beam (B) emitted from the laser generating unit (10) may correspond to the shape of the electrode tab (2). For example, the electrode tab (2) may have an approximately rectangular shape, and the beam cross-section of the laser beam (B) may also have a rectangular shape. Therefore, even if any part of the electrode tab (2) is torn, a part of the laser beam (B) can pass through the torn part.

[0054] In addition, the beam cross-section of the laser beam (B) may be equal to or slightly smaller than the size of the electrode tab (2). That is, the area on which the laser beam (B) is projected onto the normal electrode tab (2) may be equal to or slightly smaller than the area of ​​the electrode tab (2). In more detail, the laser generating unit (10) may be configured so that the area on which the laser beam (B) is projected onto the electrode tab (2) is 50% to 99%, preferably 70% to 99%, of the area of ​​the electrode tab (2).

[0055] Therefore, a normal electrode tab (2) can completely block the laser beam (B), and a defective electrode tab (2) can allow part of the laser beam (B) to pass through.

[0056] However, it is not limited thereto, and it is also possible for the beam cross-section of the laser beam (B) to be formed larger than the electrode tab (2). In this case, the controller (40) can determine whether the electrode tab (2) is defective based on the area of ​​the laser beam incident on the detection unit (20) when the electrode tab (2) blocks the laser beam (B). In more detail, if the laser beam (B) is not detected in a preset area by the detection unit (20) when the electrode tab (2) blocks the laser beam (B), the controller (40) can determine the electrode tab (2) to be normal. On the other hand, if the laser beam (B) is detected in a preset area by the detection unit (20) when the electrode tab (2) blocks the laser beam (B), the controller (40) can determine the electrode tab (2) to be defective.

[0057] The laser generating unit (10) may be configured to emit a laser beam (B) toward the detection unit (20) when the electrode tab (2) passes a position where the laser beam (B) is blocked. This may mean that the laser generating unit (10) is not only turned on and off at a predetermined cycle, but also includes a case where the laser generating unit (10) is maintained in an on state. The controller (40) may be electrically connected to the laser generating unit (10) and may control the laser generating unit (10).

[0058] Meanwhile, the inspection device may further include a marking unit (30) for marking the electrode tab (2) that has been judged to be defective so that it can be identified. The controller (40) may be electrically connected to the marking unit (30) and may control the marking unit (30).

[0059] The marking section (30) can be configured to mark a portion of the electrode sheet (1) corresponding to an electrode tab (2) that has been determined to be defective. Accordingly, in a subsequent process, a vision device such as a camera can easily identify the electrode tab (2) that has been determined to be defective.

[0060] More specifically, the marking unit (30) can perform marking at a position overlapping with the electrode tab (2) determined to be defective in the width direction of the electrode sheet (1). Since the moving electrode sheet (1) is kept taut by tension, the marking unit (30) can easily perform marking on the electrode sheet (1). However, this is not limited to this, and it is also possible for the marking unit (30) to be configured to perform marking on the electrode tab (2) determined to be defective.

[0061] The type of marking is not limited. For example, the marking unit (30) may attach a tag such as tape to the electrode sheet (1). As another example, the marking unit (30) may mark the electrode sheet (1) with ink.

[0062] In a subsequent process, the electrode sheet (1) can be cut into unit electrodes by a cutter (not shown), and each unit electrode can be provided with an electrode tab (2). Then, the unit electrode can be laminated between two separator sheets to manufacture a battery cell (unit cell). However, since the electrode tab (2) of the unit electrode with the marking is defective, it can be recovered and discarded in advance without being laminated between the two separator sheets. Accordingly, it is possible to prevent the unit electrode including the defective electrode tab (2) from being recovered in advance and used in the manufacture of the battery cell, and to improve the quality of the battery cell.

[0063] Figure 5 is a flowchart of an electrode tab inspection method according to another embodiment of the present invention.

[0064] Hereinafter, an inspection method that can be performed by the inspection device described above will be described as another embodiment of the present invention.

[0065] An electrode tab inspection method (hereinafter, 'inspection method') according to another embodiment of the present invention may include a step (S10) in which a laser generating unit (10) emits a laser beam (B) toward a detection unit (20) when the electrode tab (2) passes a position where the laser beam (B) incident on the detection unit (20) is blocked, and a step (S20) in which the electrode tab (2) is determined to be defective based on the result detected by the detection unit (20).

[0066] In the step (S10) of emitting a laser beam (B), the laser beam (B) emitted from the laser generating unit (10) may be blocked by a normal electrode tab (2) and may not be incident on the detection unit (20). However, if a part of the electrode tab (2) falls off or a crack occurs in the electrode tab (2), a part of the laser beam (B) may be incident on the detection unit (20).

[0067] That is, if the electrode tab (2) is defective, a portion of the laser beam (B) may be incident on the detection unit (20). Therefore, in the step (S20) of determining whether the electrode tab (2) is defective, if the laser beam (B) is detected by the detection unit (20), the electrode tab (2) may be determined to be defective.

[0068] To increase the accuracy of this judgment, in the step (S10) of emitting the laser beam (B), the area on which the laser beam (B) is projected onto the electrode tab (2) may be 50% to 99% of the area of ​​the electrode tab (2), and preferably, 70% to 99%.

[0069] However, it is not limited thereto, and if the cross-section of the laser beam (B) is sufficiently large, even if the electrode tab (2) is normal, a part of the laser beam (B) may pass through the periphery of the electrode tab (2) and be incident on the detection unit (20). In this case, it is possible to determine whether the electrode tab (2) is defective based on the area of ​​the laser beam incident on the detection unit (20) when the electrode tab (2) blocks the laser beam (B). In more detail, if the laser beam (B) is not detected in a preset area by the detection unit (20) when the electrode tab (2) blocks the laser beam (B), the electrode tab (2) may be determined to be normal. On the other hand, if the laser beam (B) is detected in a preset area by the detection unit (20) when the electrode tab (2) blocks the laser beam (B), the electrode tab (2) may be determined to be defective.

[0070] The above inspection method may further include a step (S30) of marking the electrode tab (2) determined to be defective so as to be identifiable. In the marking step, a portion of the electrode sheet (1) corresponding to the electrode tab (2) determined to be defective may be marked.

[0071] Accordingly, in a subsequent process, a vision device such as a camera can easily identify a defective electrode tab (2), and prevent a unit electrode including a defective electrode tab (2) from being used in the manufacture of a battery cell.

[0072] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0073] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0074] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0075] [Explanation of symbols]

[0076] 1: Electrode sheet 2: Electrode tab

[0077] 10: Laser generation unit 20: Detection unit

[0078] 30: Marking section 40: Controller

Claims

1. In an electrode tab inspection device for inspecting an electrode tab notched on one side of the width direction of an electrode sheet, A detection unit configured to detect an incident laser beam; A laser generating unit configured to emit a laser beam toward the detection unit; and An electrode tab inspection device including a controller that determines whether the electrode tab is defective based on a result detected by the detection unit when the electrode tab passes a position where the laser beam incident on the detection unit is blocked.

2. In paragraph 1, The above controller is an electrode tab inspection device that determines the electrode tab as defective when the laser beam is detected by the detection unit when the electrode tab passes a position where the laser beam is blocked.

3. In paragraph 1, The laser generating unit and the detection unit are arranged to face each other with the path through which the electrode tab passes between them, The above controller is an electrode tab inspection device that determines whether the electrode tab is defective based on the result detected by the detection unit when the electrode tab passes between the laser generating unit and the detection unit.

4. In paragraph 1, An electrode tab inspection device in which the laser generating unit is configured such that the cross-sectional shape of the laser beam has a shape corresponding to the electrode tab.

5. In paragraph 1, An electrode tab inspection device in which the laser generating unit is configured so that the laser beam is incident perpendicularly to one surface of the electrode tab when the electrode tab passes a position where the laser beam is blocked.

6. In paragraph 1, An electrode tab inspection device wherein the laser generating unit is configured to emit a laser beam toward the detection unit when the electrode tab passes a position where the laser beam is blocked.

7. In paragraph 1, An electrode tab inspection device further comprising a marking section for marking an electrode tab that has been judged to be defective so as to be identifiable.

8. In paragraph 7, The above marking unit is an electrode tab inspection device configured to mark a portion corresponding to an electrode tab determined to be defective among the electrode sheets.

9. In paragraph 1, An electrode tab inspection device in which the laser generating unit is configured such that the area on which the laser beam is projected onto the electrode tab is 50% to 99% of the area of ​​the electrode tab.

10. In a method for inspecting an electrode tab that is notched on one side of the width direction of an electrode sheet, A step in which the laser generating unit emits a laser beam toward the detection unit when the electrode tab passes a position where the laser beam incident on the detection unit is blocked; and An electrode tab inspection method comprising a step of determining whether the electrode tab is defective based on the result detected by the above detection unit.

11. In paragraph 10, An electrode tab inspection method in which, in the step of determining whether the electrode tab is defective, the electrode tab is determined to be defective if the laser beam is detected by the detection unit.

12. In paragraph 10, An electrode tab inspection method further comprising a step of marking an electrode tab that has been determined to be defective so as to be identifiable.

13. In paragraph 12, An electrode tab inspection method in which, in the above marking step, a portion corresponding to an electrode tab judged to be defective among the electrode sheets is marked.

14. In paragraph 10, An electrode tab inspection method wherein, in the step of emitting the laser beam, the area on which the laser beam is projected onto the electrode tab is 50% to 99% of the area of ​​the electrode tab.

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