Device and method for inspecting electrode stack

Abstract

The present invention provides an inspection device and an inspection method enabling the inspection of whether alignment of an electrode tab is defective without a detection error caused by diffuse reflection by photographing an electrode stack with back light and front light. The inspection device comprises: a first lighting unit for emitting first wavelength light at a side surface of the electrode stack in a first thickness direction; a second lighting unit for emitting, at a side surface of the electrode stack, in a second thickness direction, second wavelength light having a wavelength differing from that of the first wavelength light; and a camera which senses the first wavelength light and the second wavelength light, and which photographs the electrode stack in a second thickness direction so as to acquire an image.

Description

Device and method for inspecting electrode laminates

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0047641, dated April 8, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an inspection device for inspecting whether an electrode laminate is defective and an inspection method using the same. Specifically, the present invention relates to an inspection device and method for inspecting whether the tabs of an electrode laminate are aligned.

[0003] Secondary batteries, which boast high electrical properties such as high energy density and easy applicability across a wide range of product groups, are widely used not only in portable devices but also in electric or hybrid vehicles powered by electrical power sources, as well as in power storage devices. These batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they can dramatically reduce fossil fuel use, but also because they produce no byproducts from energy use.

[0004] While small mobile devices typically use one or two or three battery cells per device, medium- to large-sized devices, such as automobiles, require high output and large capacity. Therefore, medium- to large-sized battery modules or packs consisting of multiple battery cells electrically connected are used.

[0005] Meanwhile, known types of unit secondary battery cells include cylindrical, prismatic, and pouch-shaped battery cells. Since it is desirable for mid- to large-sized battery modules to be manufactured with as small a size and weight as possible, prismatic and pouch-shaped batteries, which can be stacked with high integration and have a small weight per capacity, are primarily used as battery cells for mid- to large-sized battery modules.

[0006] Among these, pouch-type battery cells have various structures depending on the manufacturing method of the electrode assembly they contain. Recently, in particular, the zigzag stacking method, in which positive and negative electrodes are alternately laminated between each layer of a zigzag-folded separator, is often used to rapidly manufacture high-capacity electrode stacks.

[0007] Fig. 1 shows an electrode laminate manufactured by zigzag stacking, and Fig. 2 is a front view of the electrode laminate of Fig. 1. Referring to these drawings, the electrode laminate (1) manufactured by the zigzag stacking method has a structure in which a plurality of electrodes (11, 12) are interposed and laminated between each layer of a separator (13) folded in a zigzag pattern. At this time, the plurality of electrodes (11, 12) have a plurality of electrode tabs (110, 120) protruding to one side.

[0008] These multiple electrode tabs (110, 120) are aligned in the thickness direction and then overlapped with each other to be connected to electrode leads that serve as terminals of the battery cell. At this time, the multiple electrode tabs (110, 120) need to be precisely aligned in the thickness direction. Therefore, it is common for a production line for such an electrode laminate (1) to be equipped with an inspection device for inspecting the alignment of the multiple electrode tabs (110, 120).

[0009] FIGS. 3 and 4 illustrate an inspection device for inspecting the electrode laminate of FIG. 1, and FIG. 5 illustrates an image of the electrode laminate. Referring to these, in order to inspect the alignment of the electrode tabs (110), a width (W) formed by overlapping the plurality of electrode tabs (110) when viewed in the thickness direction can be measured. That is, when the width (W) is excessively larger than the width of each of the electrode tabs (110), it can be determined that the plurality of electrode tabs (110) are not accurately aligned with each other.

[0010] At this time, in order to measure the width (W), it is advantageous to photograph the electrode tab (110) area with backlighting. This is because in the image (I1) in which the plurality of electrode tabs (110) that are overlapped with each other are photographed with backlighting, the silhouettes of the plurality of electrode tabs (110) are determined as one overlapping whole. Therefore, the inspection device for such an inspection is configured to include a camera (3) and a light (21) that face each other along the thickness direction with the plurality of electrode tabs (110) interposed therebetween.

[0011] However, in the case of such backlight photography, although it is advantageous for detecting a silhouette, it was observed that if there is deformation such as sagging in the electrode tab (110) made of a highly reflective metal material, detection errors may occur due to diffuse reflection, etc.

[0012] Fig. 6 is an image of an electrode stack, showing an image in which diffuse reflection has occurred. Referring to this, it has been confirmed that when any one of the plurality of electrode tabs (110), particularly the uppermost electrode tab (110), sag occurs due to gravity or the like, some of the light from the illumination irradiated from below is diffusely reflected upward, so that the portion of the electrode tab (110) that should originally be photographed as a dark shadow is photographed brightly or its silhouette becomes undetectable.

[0013] In the event of such diffuse reflection, alignment inspection of the plurality of electrode tabs (110) becomes impossible as the width (W) becomes undetectable. In this case, if it is processed as a defect, an over-detection problem occurs in which the defect rate excessively increases. Therefore, there is an urgent need for a solution to the problem of inability to detect or over-detection of defects due to such diffuse reflection.

[0014] The present invention was created under the background of the above-described prior art, and its purpose is to provide an inspection device and an inspection method that do not cause failure to detect or over-detect misalignment of electrode tabs due to diffuse reflection.

[0015] The present invention also seeks to provide an inspection device and an inspection method capable of detecting defects such as damage to a separator along with misalignment of an electrode tab.

[0016] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0017] In order to solve the above problem, the present invention provides an inspection device for vision inspection of an electrode laminate in which a plurality of electrodes are laminated together with a separator.

[0018] At this time, the plurality of electrodes have a plurality of electrode tabs that protrude from one end and are arranged in the thickness direction. The inspection device according to the present invention is for inspecting whether there is a defect in the electrode laminate, including the alignment of the plurality of electrode tabs.

[0019] The inspection device includes: a first light source that irradiates a first wavelength light to a first thickness direction side of the electrode stack; a second light source that irradiates a second wavelength light having a wavelength different from the first wavelength light to a second thickness direction side of the electrode stack; and a camera configured to detect the first wavelength light and the second wavelength light and to capture an image by photographing the electrode stack from the second thickness direction side.

[0020] At this time, the first thickness direction side and the second thickness direction side of the electrode laminate are directions that face each other. Specifically, according to an example, the first thickness direction side and the second thickness direction side may mean the upper side and the lower side of the electrode laminate, respectively.

[0021] That is, the inspection device according to the present invention is configured to be able to photograph the active laminate in both backlight and forward light. In this case, an image photographed in backlight may have a problem in that the width of the electrode tab cannot be detected or a defect is over-detected if the image is photographed abnormally due to diffuse reflection, but has the advantage of being able to more accurately detect the width of the electrode tab if the image is photographed normally. In contrast, an image photographed in forward light has the advantage of having relatively inaccurate width detection but no possibility of abnormal photographing due to diffuse reflection. The inspection device according to the present invention can obtain all of these advantages by performing backlight photography and forward light photography simultaneously as described above.

[0022] According to one embodiment of the present invention, the inspection device may further include an image processing device that processes an image acquired by the camera to extract a first image having the first wavelength light component and a second image having the second wavelength light component. That is, the camera simultaneously detects the first wavelength light and the second wavelength light to acquire a single mixed image, which the image processing device processes to separate and extract the first image having the first wavelength light component and the second image having the second wavelength light component. In other words, the first image and the second image can be separated and extracted by software from a single mixed image captured by the camera.

[0023] According to one variation, the camera may include a first sensor for detecting the first wavelength light and a second sensor for detecting the second wavelength light, and the image may include a first image acquired from the first sensor and a second image acquired from the second sensor. That is, the first image and the second image may be detected by different sensors and acquired separately from the beginning. In other words, the first image and the second image may be acquired through different hardware paths from the beginning.

[0024] The first wavelength light and the second wavelength light may be visible light of different colors selected from red, green, and blue, respectively. That is, in order to separate the first image and the second image, it is convenient for the first wavelength light and the second wavelength light to have different wavelengths among RGB. Specifically, according to one embodiment of the present invention, one of the first wavelength light and the second wavelength light may be red light and the other may be green light. For example, the first wavelength light may be red light and the second wavelength light may be green light.

[0025] The present invention also provides an inspection method for vision inspection of an electrode laminate in which a plurality of electrodes are laminated together with a separator.

[0026] The above-described plurality of electrodes have a plurality of electrode tabs that protrude from one end thereof and are arranged in the thickness direction. The inspection device according to the present invention is for inspecting whether there is a defect in the electrode laminate, including the alignment of the plurality of electrode tabs.

[0027] The above inspection method includes: an irradiation step of irradiating a first wavelength light to a first thickness direction side of the electrode laminate and irradiating a second wavelength light having a different wavelength from the first wavelength light to a second thickness direction side of the electrode laminate; a photographing step of photographing the electrode laminate from the second thickness direction side with a camera that detects the first wavelength light and the second wavelength light; an image acquisition step of acquiring a first image from the first wavelength light and a second image from the second wavelength light; and a judgment step of analyzing the first image and the second image to determine whether the electrode laminate is defective.

[0028] At this time, the first thickness direction side and the second thickness direction side of the electrode laminate are directions that face each other. Specifically, according to an example, the first thickness direction side and the second thickness direction side may mean the upper side and the lower side of the electrode laminate, respectively.

[0029] According to one embodiment of the present invention, the image acquisition step may be performed by processing the image captured by the camera to extract the first image having the first wavelength light component and the second image having the second wavelength light component. That is, in the capturing step, the camera can simultaneously detect the first wavelength light and the second wavelength light to acquire a single mixed image, and in the image acquisition step, the image processing device can process this to separate and extract the first image having the first wavelength light component and the second image having the second wavelength light component. In other words, the first image and the second image can be separated and extracted by software from a single mixed image captured by the camera.

[0030] According to one variation, the camera includes a first sensor for detecting the first wavelength light and a second sensor for detecting the second wavelength light, and the image acquisition step may be performed in a manner of acquiring the first image from the first sensor and acquiring the second image from the second sensor. That is, the first image and the second image may be detected by different sensors and acquired separately from the photographing step, in which case the photographing step may directly include the image acquisition step. In other words, the first image and the second image may be acquired through different hardware paths from the beginning.

[0031] The above judgment step may include a tab defect judgment step for judging whether the plurality of electrode tabs are misaligned.

[0032] The above tab defect determination step may be performed by detecting the width of the plurality of electrode tabs in an overlapping state from at least one of the first image and the second image, determining a good product if the width is less than or equal to a predetermined value, and determining a defective product if the width exceeds the predetermined value. This is because if the plurality of electrode tabs are all aligned at the same position along the thickness direction, the width will be the same as the width of each electrode tab, and the more poorly the alignment of the plurality of electrode tabs is, the greater the width will be.

[0033] The above tab defect determination step may include: a first determination step of analyzing the first image to determine whether the plurality of electrode tabs are misaligned; and a second determination step of analyzing the second image to determine whether the plurality of electrode tabs are misaligned. That is, in the first determination step, the width may be detected from the first image captured with backlight, and in the second determination step, the width may be detected from the second image captured with forward light. In this way, by using two different means for detecting the width together, errors in the inspection results may be reduced.

[0034] According to one embodiment of the present invention, the second judgment step may be performed after the first judgment step, on the condition that a defective product is determined in the first judgment step. If a detection error due to diffuse reflection occurs in the first judgment step, a defective product will be determined, and if a detection error due to diffuse reflection does not occur, the width detected from the first image is more accurate than the second image, so the second judgment step only needs to be performed when a defective product is determined in the first judgment step, which is more economical and efficient.

[0035] However, unlike this, it goes without saying that the effect of the present invention can be exerted even if the first judgment step is performed after the second judgment step, under the condition that a defective product is determined in the second judgment step.

[0036] According to one variation, the tab defect determination step may additionally include a third determination step for finally determining a good product if a good product determination is made in at least one of the first determination step and the second determination step. In this case, the highest accuracy can be achieved by always performing both the first and second determination steps.

[0037] The above-described judgment step may additionally include a membrane defect judgment step for analyzing the second image to determine whether a defect is due to damage to the membrane. In the above-described inspection method, since the electrode laminate is photographed not only in backlight but also in forward light, defects due to surface damage that appears on the exterior can also be detected.

[0038] In this case, the membrane defect determination step can be performed together with the second determination step.

[0039] The present invention provides an inspection device and an inspection method capable of detecting misalignment of an electrode tab without error even when diffuse reflection occurs on the electrode tab by performing backlight and forward light photography together.

[0040] In addition, according to the present invention, an inspection device and an inspection method are provided that can detect defects due to surface damage such as damage to a separator along with misalignment of tabs by performing backlight photography and forward light photography together.

[0041] Another advantage of the inspection device and inspection method according to one embodiment of the present invention is that they can be efficiently and economically constructed and performed by software-based separation and extraction of backlight and forward light images from a single mixed image.

[0042] In addition, according to one embodiment of the present invention, an inspection method that is efficient and economical in terms of time and energy is provided by performing a judgment on whether there is a defect from a forward-looking image only when the alignment of the electrode tab is judged to be poor from a backlight image.

[0043] In addition, the present invention may have various other effects, which will be described in each embodiment, or the description of effects that can be easily inferred by a person skilled in the art will be omitted.

[0044] Fig. 1 shows an electrode laminate manufactured by zigzag stacking, and Fig. 2 is a front view of the electrode laminate of Fig. 1.

[0045] Figures 3 and 4 show an inspection device for inspecting the electrode laminate of Figure 1.

[0046] Figure 5 shows an image of an electrode stack.

[0047] Figure 6 is an image of an electrode stack, showing an image in which diffuse reflection has occurred.

[0048] Fig. 7 shows an electrode laminate that is a test object according to one embodiment of the present invention, and Fig. 8 is a front view of the electrode laminate of Fig. 1.

[0049] Figures 9 to 11 illustrate an inspection device according to one embodiment of the present invention.

[0050] Figure 12 is a flowchart showing an inspection method according to one embodiment of the present invention.

[0051] Figure 13 shows a mixed image captured by an inspection device according to one embodiment of the present invention.

[0052] FIG. 14 is a schematic diagram showing a process in which an image processing device according to one embodiment of the present invention processes the mixed image of FIG. 13 to obtain a first image and a second image.

[0053] Fig. 15 is a first image according to one embodiment of the present invention, showing an image in which no diffuse reflection occurs.

[0054] Fig. 16 is a first image according to one embodiment of the present invention, showing an image in which diffuse reflection has occurred.

[0055] Figure 17 shows a second image according to one embodiment of the present invention.

[0056] [Explanation of symbols]

[0057] 1: Electrode laminate

[0058] 11: (First) electrode

[0059] 110: (1st) Electrode tab

[0060] 12: Second electrode

[0061] 120: Second electrode tab

[0062] 13: Membrane

[0063] 21: (First) Lighting

[0064] 22: Second Light

[0065] 3: Camera

[0066] 4: Image processing device

[0067] I0: Mixed image

[0068] I1: (First) video

[0069] I2: Second video

[0070] W: width

[0071] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0072] Although the terms "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0073] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0074] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0075] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0076] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0077] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C to D", this means C or more and D or less, unless otherwise stated.

[0078] Hereinafter, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0079]

[0080] [Structure of the electrode stack]

[0081] Hereinafter, with reference to FIGS. 7 and 8, the structure of an electrode laminate that is an object of inspection of an inspection device and an inspection method according to an embodiment of the present invention will be briefly described. In this embodiment, an electrode laminate manufactured through a zigzag stacking method is exemplified, but it will be understood through the following description that the inspection device and inspection method according to the present invention can be any object of inspection as long as it has a structure including a plurality of electrode tabs aligned in one direction, regardless of the manufacturing method or other structure.

[0082] Fig. 7 illustrates an electrode laminate to be inspected according to one embodiment of the present invention, and Fig. 8 is a front view of the electrode laminate of Fig. 1. Referring to these drawings, the electrode laminate (1) can be configured by laminating a separator (13), a first electrode (11), and a second electrode (12).

[0083] The first electrode (11) may be an anode or a cathode, and the second electrode (12) may be a cathode or an anode. That is, the first electrode (11) and the second electrode (12) may be one or the other of the anode and the cathode, respectively.

[0084] The first electrode (11) and the second electrode (12) may each include a metal foil made of aluminum or copper.

[0085] The above first electrode (11) and the above second electrode (12) can be alternately and repeatedly laminated along the thickness direction.

[0086] The first electrode (11) and the second electrode (12) may each have a first electrode tab (110) and a second electrode tab (120) protruding to one side and the other side, respectively. The first electrode tab (110) and the second electrode tab (120) are arranged in the thickness direction, and preferably, may be aligned at the same position. The first electrode tab (110) and the second electrode tab (120) may then be overlapped in the thickness direction and connected to the first electrode lead and the second electrode lead, respectively, thereby functioning as terminals of the battery cell.

[0087] The separator (13) is interposed between the first electrode (11) and the second electrode (12) and can be folded in a zigzag manner. More specifically, the separator (13) has a sheet shape having a first side and a second side facing each other, and can be folded alternately so that the first side contacts both surfaces of the first electrode (11) and the second side contacts both surfaces of the second electrode (12).

[0088] The separator (13) is laminated with the first electrode (11) and the second electrode (12), folded, and then finally wrapped around the surface of the electrode laminate (1). The separator (13) can then wrap and finish the electrode laminate (1) by having its end fused or adhered to itself.

[0089]

[0090] [Inspection device]

[0091] Hereinafter, with reference to FIGS. 9 to 11, the structure of an inspection device according to an embodiment of the present invention will be described in detail. In the examples below, the electrode tab refers to the first electrode tab (110). However, it goes without saying that the inspection device described below can also be used for alignment inspection of the second electrode tab (120).

[0092] FIGS. 9 to 11 of the present invention illustrate an inspection device according to one embodiment of the present invention. Referring to these drawings, the inspection device according to one embodiment of the present invention includes: a first light (21) that irradiates a first wavelength light to a first thickness direction side of the electrode stack (1); a second light (22) that irradiates a second wavelength light having a wavelength different from the first wavelength light to a second thickness direction side of the electrode stack (1); and a camera (3) that is configured to detect the first wavelength light and the second wavelength light and acquires an image by photographing the electrode stack (1) from the second thickness direction side.

[0093] At this time, the first thickness direction side and the second thickness direction side of the electrode laminate (1) are directions that face each other. Specifically, the first thickness direction side and the second thickness direction side according to an example may mean the upper side and the lower side of the electrode laminate (1), respectively.

[0094] That is, the inspection device according to the present invention is configured to be able to photograph the electrode stack (1) in both backlight and forward light. At this time, an image photographed in backlight may have a problem in that the width of the electrode tab (110) cannot be detected or a defect is over-detected if the image is photographed abnormally due to diffuse reflection, but has the advantage of being able to more accurately detect the width of the electrode tab (110) if the image is photographed normally. In contrast, an image photographed in forward light has the advantage of having relatively inaccurate width detection but no possibility of abnormal photographing due to diffuse reflection. The inspection device according to the present invention can obtain all of these advantages by performing backlight photography and forward light photography simultaneously as described above.

[0095] As shown in Fig. 11, the inspection device according to one embodiment of the present invention may further include an image processing device (4) that processes the image acquired by the camera (3) to extract the first image having the first wavelength light component and the second image having the second wavelength light component. In this case, the first image is an image of the electrode stack (1) taken in backlight, and the second image is an image of the electrode stack (1) taken in forward light.

[0096] The above image processing device (4) can be configured to be connected to the camera (3) and receive an image signal from the camera (3) and process it.

[0097] According to one variation, the camera (3) may include a first sensor that detects the first wavelength light and a second sensor that detects the second wavelength light. In this case, the camera (3) may detect the first wavelength light through the first sensor to obtain the first image, and detect the second wavelength light through the second sensor to obtain the second image.

[0098] Referring back to FIG. 10, the first wavelength light and the second wavelength light may be visible light of different colors selected from red, green, and blue, respectively. That is, in order to separate the first image and the second image, it is convenient for the first wavelength light and the second wavelength light to have different wavelengths among RGB. Specifically, according to one embodiment of the present invention, one of the first wavelength light and the second wavelength light may be red light and the other may be green light. For example, the first wavelength light may be red light and the second wavelength light may be green light.

[0099]

[0100] [Testing method]

[0101] Hereinafter, with reference to FIGS. 12 to 17, an inspection method according to one embodiment of the present invention will be described in detail.

[0102] Fig. 12 is a flowchart showing an inspection method according to one embodiment of the present invention. Referring to this, the inspection method according to one embodiment of the present invention includes: an irradiation step (S1) of irradiating a first wavelength light to a first thickness direction side of the electrode laminate (1) and irradiating a second wavelength light having a different wavelength from the first wavelength light to a second thickness direction side of the electrode laminate (1); a photographing step (S2) of photographing the electrode laminate from the second thickness direction side with a camera (3) detecting the first wavelength light and the second wavelength light; an image acquisition step (S3) of acquiring a first image (I1) from the first wavelength light and a second image (I2) from the second wavelength light; and a judgment step (S4) of analyzing the first image (I1) and the second image (I2) to determine whether the electrode laminate (1) is defective.

[0103] Fig. 13 shows a mixed image captured by an inspection device according to one embodiment of the present invention, and Fig. 14 is a schematic diagram showing a process in which an image processing device according to one embodiment of the present invention processes the mixed image of Fig. 13 to obtain a first image and a second image. Referring to this, according to one embodiment of the present invention, in the capturing step (S2), the camera (3) can simultaneously detect the first wavelength light and the second wavelength light to obtain one mixed image (I0).

[0104] At this time, the image acquisition step (S3) can be performed in a manner of processing the mixed image (I0) to extract the first image (I1) having the first wavelength light component and the second image (I2) having the second wavelength light component. That is, in the photographing step (S2), the camera (3) can simultaneously detect the first wavelength light and the second wavelength light to acquire one mixed image (I0), and in the image acquisition step (S3), the image processing device (4) can process this to separate and extract the first image (I1) having the first wavelength light component and the second image (I2) having the second wavelength light component. In other words, the first image (I1) and the second image (I2) can be separated and extracted by software from one mixed image (I0) captured by the camera (3).

[0105] According to one variation, the camera (3) includes a first sensor for detecting the first wavelength light and a second sensor for detecting the second wavelength light, and the image acquisition step (S3) can be performed in a manner of acquiring the first image (I1) from the first sensor and acquiring the second image (I2) from the second sensor. That is, the first image (I1) and the second image (I2) can be detected by different sensors and acquired separately from the photographing step (S2), and in this case, the photographing step (S2) can directly include the image acquisition step (S3). In other words, the first image (I1) and the second image (I2) can be acquired through different hardware paths from the beginning.

[0106] Referring again to FIG. 12, the determination step (S4) according to one embodiment of the present invention may include a tab defect determination step (S41, S42) for determining whether the plurality of electrode tabs (110) are misaligned.

[0107] At this time, the tab defect determination step (S41, S42) may include a first determination step (S41) of analyzing the first image (I1) to determine whether the plurality of electrode tabs (110) are misaligned.

[0108] Fig. 15 is a first image according to one embodiment of the present invention, showing an image in which no diffuse reflection occurs. Referring to this, the first judgment step (S41) may be performed by detecting the width (W) of the plurality of electrode tabs (110) in an overlapping state from the first image (I1), and determining a good product if the width (W) is less than or equal to a predetermined value, and determining a defective product if the width (W) exceeds the predetermined value. This is because if the plurality of electrode tabs (110) are all aligned at the same position along the thickness direction, the width (W) will be the same as the width of each of the electrode tabs (110), and the worse the alignment of the plurality of electrode tabs (110), the larger the width (W) will be. That is, if the plurality of electrode tabs (110) are not aligned with each other and their positions are misaligned, the width (W) is measured to be large on the first image (I1) and / or the second image (I2), and therefore, if the width (W) exceeds a predetermined value, it can be judged as defective.

[0109] At this time, since the direction in which the camera (3) is looking is opposite to the irradiation direction of the first light (21), the first image (I1) becomes a backlit image. As a result, the first image (I1) expresses the overall silhouette of the plurality of electrode tabs (110) overlapping each other, and the silhouettes of the individual electrode tabs (110) are not expressed. In other words, in the first image (I1), the area where the electrode tabs (110) are located is expressed as a dark shadow, and the area outside thereof is expressed as bright. Accordingly, it is easy to detect the width (W) in the first image (I1).

[0110] Fig. 16 is a first image according to one embodiment of the present invention, which shows an image in which diffuse reflection has occurred. Referring to this, the second wavelength light may be diffusely reflected as the electrode tab (110) sags or deforms. Specifically, as the electrode tab (110) sags, the light irradiated downward from the first light (21) is diffusely reflected upward, so that the portion of the electrode tab (110), which should originally be expressed as a dark shadow, is expressed brightly, so that the silhouette of the electrode tab (110) may not be accurately reflected in the first image (I1). In this case, it is possible that it is impossible to detect the width (W) from the first image (I1), or the width (W) may be detected incorrectly, resulting in a defective judgment even when there is no defective product.

[0111] Referring back to FIG. 12, the tab defect determination step (S41, S42) may include a second determination step (S42) of analyzing the second image (I2) to determine whether the plurality of electrode tabs (110) are misaligned in order to solve the problem of defects not being detected or being excessively detected in the first determination step (S41).

[0112] Fig. 17 illustrates a second image according to one embodiment of the present invention. Referring to this, the second judgment step (S42) may be performed by detecting the width (W) of the plurality of electrode tabs (110) in an overlapping state from the second image (I2), and determining a good product if the width (W) is below a predetermined value, and determining a defective product if the width (W) exceeds the predetermined value.

[0113] At this time, since the direction in which the camera (3) is looking is the same as the irradiation direction of the second light (22), the first image (I1) becomes a backlit image. As a result, the silhouettes of each of the plurality of electrode tabs (110) are individually expressed in the second image (I2). In other words, in the second image (I2), the area where the electrode tabs (110) are located are expressed brightly so that their surface shapes can be identified, and the outer area thereof is expressed as a dark shadow. Accordingly, in the second image (I2), there is no occurrence of the width of the electrode tabs (110) not being detected due to diffuse reflection.

[0114] That is, in the first judgment step (S41), the width (W) can be detected from the first image (I1) photographed in backlight, and in the second judgment step (S42), the width (W) can be detected from the second image (I2) photographed in forward light. In this way, by using two different means for detecting the width (W) together, errors in the inspection results can be reduced.

[0115] Referring back to FIG. 12, according to one embodiment of the present invention, the second judgment step (S42) may be performed after the first judgment step (S41) on the condition that a defective product is determined in the first judgment step (S41). If a detection error due to diffuse reflection occurs in the first judgment step (S41), a defective product will be determined, and if a detection error due to diffuse reflection does not occur, the width (W) detected from the first image (I1) is more accurate than that of the second image (I2), so the second judgment step (S42) only needs to be performed when a defective product is determined in the first judgment step (S41), which is more economical and efficient.

[0116] However, unlike this, it goes without saying that the effect of the present invention can be exerted even if the first judgment step (S41) is performed under the condition that a defective product is determined in the second judgment step (S42) after the second judgment step (S42).

[0117] According to one variation, the tab defect determination step (S41, S42) may additionally include a third determination step for finally determining a good product determination if a good product determination is made in at least one of the first determination step (S41) and the second determination step (S42). In this case, regardless of the order in which the first determination step (S41) and the second determination step (S42) are performed, if a good product determination is made in the first determination step (S41) or a good product determination is made in the second determination step (S42), the electrode laminate (1) can be determined to be a good product without a tab defect.

[0118] Referring back to FIG. 12, the judgment step (S4) may additionally include a membrane defect judgment step (S43) for analyzing the second image (I2) to determine whether a defect is due to damage to the membrane (13). In the inspection method, since the electrode laminate (1) is photographed not only with backlight but also with forward light, defects due to surface damage that appears on the exterior can also be detected.

[0119] In this case, the membrane defect determination step (S43) can be performed together with the second determination step (S42).

[0120] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0121] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. In an inspection device for vision inspection of an electrode laminate in which a plurality of electrodes are laminated together with a separator, The above plurality of electrodes have a plurality of electrode tabs that protrude from one end and are arranged in the thickness direction, The above inspection device: A first light source that irradiates light of a first wavelength to a first thickness direction side of the electrode laminate; A second light that irradiates a second wavelength light having a wavelength different from the first wavelength light to the second thickness direction side of the electrode laminate; and An inspection device comprising a camera configured to detect the first wavelength light and the second wavelength light, and to obtain an image by photographing the electrode stack from the second thickness direction side.

2. In claim 1, An inspection device further comprising an image processing device that processes an image acquired by the camera to extract a first image having the first wavelength light component and a second image having the second wavelength light component.

3. In claim 1, The camera includes a first sensor that detects the first wavelength light and a second sensor that detects the second wavelength light, An inspection device, wherein the image includes a first image obtained from the first sensor and a second image obtained from the second sensor.

4. In claim 1, An inspection device wherein the first wavelength light and the second wavelength light are visible light of different colors selected from red, green, and blue, respectively.

5. In claim 4, An inspection device, wherein one of the first wavelength light and the second wavelength light is red light and the other is green light.

6. In an inspection method for vision inspection of an electrode laminate in which a plurality of electrodes are laminated together with a separator, The above plurality of electrodes have a plurality of electrode tabs that protrude from one end and are arranged in the thickness direction, The above inspection method is: An irradiation step of irradiating a first wavelength light to a first thickness direction side surface of the electrode laminate and irradiating a second wavelength light having a wavelength different from the first wavelength light to a second thickness direction side surface of the electrode laminate; A photographing step of photographing the electrode laminate from the second thickness direction side using a camera that detects the first wavelength light and the second wavelength light; An image acquisition step of acquiring a first image from the first wavelength light and acquiring a second image from the second wavelength light; and An inspection method, comprising a judgment step of analyzing the first image and the second image to determine whether the electrode laminate is defective.

7. In claim 6, An inspection method, wherein the image acquisition step is performed by processing an image captured by the camera to extract the first image having the first wavelength light component and the second image having the second wavelength light component.

8. In claim 6, The camera includes a first sensor that detects the first wavelength light and a second sensor that detects the second wavelength light, An inspection method, wherein the image acquisition step is performed by acquiring the first image from the first sensor and acquiring the second image from the second sensor.

9. In claim 6, An inspection method, wherein the above judgment step includes a tab defect judgment step for judging whether the plurality of electrode tabs are misaligned.

10. In claim 9, The above tab defect determination step is an inspection method performed by detecting a width of the plurality of electrode tabs in an overlapping state from at least one of the first image and the second image, and determining a good product if the width is less than a predetermined value, and determining a defective product if the width exceeds the predetermined value.

11. In claim 9, The above tab defect determination steps are: A first judgment step of analyzing the first image to determine whether the plurality of electrode tabs are misaligned; An inspection method comprising: a second judgment step of analyzing the second image to determine whether the plurality of electrode tabs are misaligned; 12. In claim 11, An inspection method in which the second judgment step is performed after the first judgment step, under the condition that a defective product is determined in the first judgment step.

13. In claim 11, An inspection method in which the first judgment step is performed after the second judgment step, under the condition that a defective product is determined in the second judgment step.

14. In claim 11, An inspection method, wherein the above tab defect determination step further includes a third determination step for finally determining a good product if a good product determination is made in at least one of the first determination step and the second determination step.

15. In claim 9, An inspection method, wherein the above judgment step further includes a membrane defect judgment step for analyzing the second image to determine whether the membrane is defective due to damage.

16. In claim 11, The above judgment step further includes a membrane defect judgment step of analyzing the second image to determine whether the membrane is defective due to damage. An inspection method in which the above membrane defect determination step is performed together with the second determination step.

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