KR20220020506A - A system for inspecting a defect in a battery cell and a method for inspecting a defect in a battery cell - Google Patents

Abstract

The present invention relates to a battery cell defect inspection system and a battery cell defect inspection method, wherein the battery cell defect inspection system comprises: a measuring unit that captures an image or an image of an electrode tab portion in a battery cell to detect a tap disconnection of the battery cell; a main server that is network-linked with the measurement unit to receive and store images captured by the measurement unit; and a determination unit that receives the image or image stored in the main server and analyzes the transmitted image or image to detect whether an electrode tab is disconnected or an overhang of the electrode assembly occurs, wherein the determination unit is network interlocked with the main server It includes at least two or more sub-PCs.

Description

Battery cell defect inspection system and battery cell defect inspection method

The present invention relates to a battery cell defect inspection system and a battery cell defect inspection method, and more particularly, to a battery cell defect inspection system and battery capable of detecting a disconnection of an electrode tab portion in a battery cell or an overhang of an electrode assembly through CT imaging It relates to a cell defect inspection method.

Recently, rechargeable batteries capable of charging and discharging have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, etc., which have been proposed as a way to solve air pollution of conventional gasoline vehicles and diesel vehicles using fossil fuels. Accordingly, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future than now.

These secondary batteries are sometimes classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, etc. depending on the composition of the electrode and electrolyte. is increasing In general, secondary batteries include a cylindrical battery and a prismatic battery in which an electrode assembly is built in a cylindrical or prismatic metal can, and a pouch-type battery in which the electrode assembly is built in a pouch-type case of an aluminum laminate sheet, depending on the shape of the battery case. The electrode assembly built into the battery case consists of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is a power generating element capable of charging and discharging. It is classified into a jelly-roll type wound with a separator interposed therebetween, and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween.

The positive electrode and the negative electrode are formed by applying a positive electrode slurry containing a positive electrode active material and a negative electrode slurry containing a negative electrode active material to a positive electrode current collector and a negative electrode current collector, respectively, and drying and rolling them.

Meanwhile, an electrode tab is formed on one side of the electrode assembly to connect the battery cell to the outside, and an electrode lead is welded to the electrode tab. The electrode lead is drawn out of the battery case.

However, during the electrode manufacturing process and the electrode assembly assembly process, disconnection due to cracks may occur in the electrode tab due to the difference in elongation of the holding part and the uncoated part, physical external force caused by welding, etc. do. Conventionally, an eddy current test method or the like has been used to detect such cracks.

1 is a schematic diagram illustrating a crack detection principle using an eddy current.

Referring to FIG. 1 , when an alternating current is applied to a coil 1 to induce an eddy current, a magnetic field 2 is generated around the coil. When the coil 1 in which the magnetic field 2 is formed is brought to the surface of the inspection object 3, an induced electromotive force is generated on the surface of the inspection object 3 due to electromagnetic induction. This induced electromotive force causes a current to flow in a direction that disturbs the magnetic field, and this current is called an eddy current (4). The eddy current 4 changes according to the state, position, defect, material, etc. of the surface of the inspection object 3 . Therefore, the crack inside the battery cell is detected using the characteristic of the eddy current. That is, the battery cell, the object to be inspected, is passed between the eddy current sensors, the eddy current signal is measured, and the point where the eddy current signal is changed is considered as the eddy current signal has changed due to the crack and cracks are detected.

However, this method of measuring using the eddy current has a problem in that it is difficult to detect when the length of the crack generated in the electrode tab is small.

Therefore, there is a need to develop an inspection method capable of detecting disconnection due to minute cracks occurring in the electrode tab and detecting defects such as disconnection within a short time.

Korean Patent No. 10-2023739

The present invention has been devised to solve the above problems, and while improving the reliability and accuracy of inspection by detecting defects such as disconnection or overhang of the end of the electrode assembly due to microcracks occurring in the electrode tab portion, the reliability and accuracy of the inspection can be improved in a short time An object of the present invention is to provide a battery cell defect inspection system and a battery cell defect inspection method capable of detecting defects within.

A battery cell defect inspection system according to the present invention includes: a measuring unit for photographing an image or an image of an electrode tab portion in a battery cell in order to detect a tap disconnection of the battery cell; a main server that is network-linked with the measurement unit to receive and store images captured by the measurement unit; and a determination unit that receives the image or image stored in the main server and analyzes the transmitted image or image to detect whether the electrode tab is disconnected or whether an overhang of the electrode assembly occurs, wherein the determination unit is connected to the main server and network It includes at least two interlocked sub-PCs (Sub-PCs).

In a specific example, the measuring unit may include: a jig on which at least one battery cell is mounted; and a photographing unit for photographing an image or an image of an electrode tab portion inside the battery cell.

In this case, the imaging unit captures an image using a computed tomography (CT) method.

In addition, the battery cell defect inspection system according to the present invention further includes a control unit that controls the operation of the measurement unit and transmits an image or image captured by the measurement unit to the main server.

Meanwhile, the two or more sub-fish may analyze the image or different parts of the image.

In addition, the present invention provides a method for inspecting a battery cell defect, the method comprising: photographing an image or an image of an electrode tab portion in a battery cell through a measuring unit; storing the image or video in a main server; transmitting an image or video stored in the main server to two or more sub-PCs connected to the main server in a network, respectively; and analyzing images or images stored in two or more sub-PCs, respectively, to detect whether an electrode tab is disconnected or an overhang of the electrode assembly occurs.

In a specific example, the battery cell defect inspection method according to the present invention may inspect two or more battery cells at the same time.

In a specific example, the image or image is taken using an X-ray computed tomography (CT) method.

In this case, the battery cell defect inspection method according to the present invention may further include the step of reconstructing the image or the image into a three-dimensional image.

In a specific example, the step of detecting whether the electrode tab is disconnected or whether an overhang has occurred includes a process of visually analyzing the images or images stored in the sub-PC to confirm the disconnection portion.

In another example, in each sub-fish, the image or different parts of the image may be analyzed.

In addition, in the step of detecting whether the electrode tab is disconnected or an overhang occurs, the process of analyzing the images or images stored in the sub-PC may be performed at the same time.

In addition, the battery cell defect inspection method according to the present invention further includes, after the step of detecting whether the electrode tab is disconnected or whether an overhang occurs, transmitting the detection result to the main server.

The battery cell defect inspection system and battery cell defect inspection method according to the present invention detect defects such as disconnection of an electrode tab part or an overhang of an electrode assembly through CT imaging to detect all defects of a minute degree, so reliability and accuracy of inspection can improve

In addition, the battery cell defect inspection system and battery cell defect inspection method according to the present invention reduce the time required for defect detection by analyzing an image or image of an electrode tap portion using a plurality of sub-fish connected to a main server and a network. can do it

1 is a schematic diagram illustrating a crack detection principle using an eddy current.
2 is a block diagram showing the configuration of a battery cell defect inspection system according to the present invention.
3 is a schematic diagram showing the configuration of a measurement unit in the battery cell defect inspection system according to the present invention.
4 is a flowchart illustrating a procedure of a battery cell defect inspection method according to the present invention.
5 is a schematic diagram illustrating a battery cell defect inspection method according to an embodiment of the present invention.
6 is a photograph showing an analysis tool for detecting the occurrence of disconnection or overhang in the battery cell defect inspection method according to the present invention.
7 is a photograph showing a portion where a disconnection occurs in the battery cell defect inspection method according to the present invention.
8 is a schematic diagram illustrating a battery cell defect inspection method according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined in

In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only the case where the other part is “directly on” but also the case where there is another part in between. Conversely, when a part of a layer, film, region, plate, etc. is said to be “under” another part, it includes not only cases where it is “directly under” another part, but also cases where another part is in between. In addition, in the present application, “on” may include the case of being disposed not only on the upper part but also on the lower part.

Hereinafter, the present invention will be described in detail.

2 is a block diagram showing the configuration of a battery cell defect inspection system according to the present invention.

Referring to FIG. 2 , the battery cell defect inspection system 10 according to the present invention includes: a measuring unit 100 for photographing an image or an image of an electrode tab portion in a battery cell in order to detect a tap disconnection of the battery cell; a main server 200 that is network-linked with the measurement unit to receive and store images captured by the measurement unit; and a determination unit 300 that receives the image or image stored in the main server 200 and analyzes the transmitted image or image to detect whether an electrode tab is disconnected or an overhang of the electrode assembly occurs, The determination unit includes at least two or more sub-PCs (Sub-PCs, 310, 320, 330, 340) that are network-linked with the main server.

As described above, there has been a method of using an eddy current as a method of detecting defects such as disconnection in the prior art, but this method has a problem in that it is difficult to detect the cracks generated in the electrode tabs when the length of the cracks is small.

The battery cell defect inspection system according to the present invention detects defects such as disconnection of an electrode tab portion or an overhang of an electrode assembly through CT imaging, thereby detecting all defects of a minute degree, thereby improving reliability and accuracy of inspection. On the other hand, the overhang refers to a phenomenon in which an anode and an anode are misaligned in the electrode assembly, so that the end of the anode exceeds the end of the cathode.

In addition, the battery cell defect inspection system according to the present invention can reduce the time required for defect detection by analyzing an image or an image obtained by photographing an electrode tap portion using a plurality of sub-PCs linked to the main server and a network.

Hereinafter, a battery cell defect inspection system according to the present invention will be described in detail.

Referring to FIG. 2 , the battery cell defect inspection system 10 according to the present invention includes a measurement unit 100 , a main server 200 , and a determination unit 300 . Here, the measurement unit 100 takes an image or an image of the electrode tab portion in the battery cell.

3 is a schematic diagram showing the configuration of a measurement unit in the battery cell defect inspection system according to the present invention.

Referring to FIG. 3 , the measurement unit 100 includes a jig 120 and a photographing unit 130 .

The jig 120 may mount at least one battery cell 110 , and serves to fix the battery cell 110 so as to easily take an image or an image of the tab portion. Referring to FIG. 3 , the jig 120 has a space in which two battery cells can be mounted so that two battery cells can be photographed simultaneously when taking an image or video, but battery cells that can be mounted on the jig at once There is no particular limitation on the number of Also, referring to FIG. 3 , the battery cells are mounted in a direction perpendicular to the ground, but the shape of the jig and the mounting method of the battery cells may be appropriately changed according to the photographing method.

Meanwhile, the photographing unit 130 captures an image or an image of the electrode tab portion inside the battery cell. In this case, although there is no particular limitation on the imaging method, for example, an X-ray computed tomography (CT) method may be used. In this way, when a defect in a battery cell is detected through CT imaging, it is possible to accurately detect a disconnection or a minute overhang caused by a micro crack that cannot be detected by the same method as an eddy current. Also, as will be described later, by reconstructing the battery cell into a three-dimensional image using the image obtained through CT imaging, the size and occurrence of cracks can be accurately identified.

In this case, the photographing unit 130 transmits the X-ray tube 131 for applying X-rays to one surface of the battery cell 110 and the battery cell 110 from the opposite side of the X-ray tube 131 . and a detector 132 that detects X-rays and outputs them as images or images. The X-ray tube 131 and the detector 132 may photograph the battery cell 110 from various angles and directions, for example, by scanning the battery cell 110 while reciprocating up and down, an image of the electrode tab portion or image can be obtained. In this case, the plane formed by the region to be photographed and the direction in which the X-rays are applied may be photographed in a state perpendicular to each other.

Meanwhile, the battery cell 110 may have a structure in which an electrode assembly 111 having a structure in which positive electrodes, separators, and negative electrodes are alternately stacked is accommodated in the battery case 112 . The positive electrode and the negative electrode have a structure in which an active material layer is formed through drying and rolling processes after an electrode slurry including an electrode active material is applied to a current collector, respectively. When the electrode assembly 111 is accommodated in the battery case 112 , an electrolyte may be injected therein and sealed to manufacture a battery cell.

Here, the current collector may be a positive electrode current collector or a negative electrode current collector, and the electrode active material may be a positive electrode active material or a negative electrode active material. In addition, the electrode slurry may further include a conductive material and a binder in addition to the electrode active material.

In the present invention, the positive electrode current collector is generally made to have a thickness of 3 to 500 μm. The positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel. Carbon, nickel, titanium, silver, etc. surface-treated on the surface of the can be used. The current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on the surface thereof, and various forms such as a film, sheet, foil, net, porous body, foam body, and non-woven body are possible.

In the case of a sheet for a negative electrode current collector, it is generally made to a thickness of 3 to 500 μm. Such a negative current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel. Carbon, nickel, titanium, a surface-treated material such as silver, aluminum-cadmium alloy, etc. may be used. In addition, like the positive electrode current collector, the bonding strength of the negative electrode active material may be strengthened by forming fine irregularities on the surface, and may be used in various forms such as a film, sheet, foil, net, porous body, foam, non-woven body, and the like.

In the present invention, the positive active material is a material capable of causing an electrochemical reaction, as a lithium transition metal oxide, containing two or more transition metals, for example, lithium cobalt oxide (LiCoO ₂ ) substituted with one or more transition metals. ), layered compounds such as lithium nickel oxide (LiNiO ₂ ); lithium manganese oxide substituted with one or more transition metals; Formula LiNi _1-y M _y O ₂ (wherein M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga and includes at least one of the above elements, 0.01≤y≤0.7) Lithium nickel-based oxide represented by; Li _1+z Ni _1/3 Co _1/3 Mn _1/3 O ₂ , Li _1+z Ni _0.4 Mn _0.4 Co _0.2 O ₂ , etc. Li _1+z Ni _b Mn _c Co _{1-(b+c+d )} M _d O _(2-e) A _e (where -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d <1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl) a lithium nickel cobalt manganese composite oxide; Formula Li _1+x M _1-y M' _y PO _4-z X _z where M = transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S, or N, and -0.5≤x≤+0.5, 0≤y≤0.5, 0≤z≤0.1 olivine-based lithium metal phosphate represented by), but is not limited thereto.

The negative electrode active material includes, for example, carbon such as non-graphitizable carbon and graphitic carbon; Li _x Fe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _1-x Me' _y O _z (Me: Mn, Fe, Pb, Ge; Me' : metal composite oxides such as Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogen; 0<x≤1;1≤y≤3;1≤z≤8); lithium metal; lithium alloy; silicon-based alloys; tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , metal oxides such as Bi ₂ O ₅ ; conductive polymers such as polyacetylene; A Li-Co-Ni-based material or the like can be used.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive active material. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, graphite such as natural graphite or artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The binder is a component that assists in bonding between the active material and the conductive material and bonding to the current collector, and is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, poly propylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butyrene rubber, fluororubber, various copolymers, and the like.

Meanwhile, the separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 μm, and the thickness is generally 5 to 300 μm. As such a separation membrane, For example, olefin polymers, such as chemical-resistant and hydrophobic polypropylene; A sheet or non-woven fabric made of glass fiber or polyethylene is used.

In the electrode assembly, an electrode tab is formed on one side of the electrode, and the electrode tab may be a positive electrode tab or a negative electrode tab. A positive electrode lead and a negative electrode lead are respectively connected to the positive electrode tab and the negative electrode tab. The positive lead and the negative lead are drawn out of the battery case to serve as a terminal electrically connected to the outside. In this case, the positive electrode lead and the negative electrode lead may be joined to the positive electrode tab and the negative electrode tab by welding, respectively. As a welding method, a well-known thing can be used, for example, ultrasonic welding or laser welding can be used.

Meanwhile, the battery case is not particularly limited as long as it is used as an exterior material for battery packaging, and a cylindrical, prismatic, or pouch type may be used, but in detail, a pouch type battery case may be used. The pouch-type battery case is typically made of an aluminum laminate sheet, and may include an inner sealant layer for sealing, a metal layer preventing material penetration, and an outer resin layer forming the outermost layer of the case. Hereinafter, detailed description of the battery case will be omitted since it is known to those skilled in the art.

An electrode tab 113 is drawn out from one side of the electrode constituting the electrode assembly 111 for electrical connection with an external device or another battery cell. The electrode tab 113 may be a positive electrode tab or a negative electrode tab, and the positive electrode tab and the negative electrode tab are coupled to each other through welding with the electrode lead 114 . The electrode lead is drawn out of the battery case. In FIG. 3 , as the electrode tabs 113 are drawn out to both sides of the electrode assembly 111 , the electrode leads 114 are also drawn out from both sides of the battery case, but there are no special restrictions on the drawing out shapes of the electrode tabs and the electrode leads. does not

In the present invention, the portion where the image or image is photographed by the photographing unit 130 is the electrode tab 113 portion drawn out to one side of the electrode assembly 111 , and other parts welded to the electrode tab 113 . A portion of the electrode lead 114 may also be a detection target.

When an image or an image of the electrode tab 113 portion in the battery cell 110 is photographed by the measurement unit 100 , the photographed image or image is transmitted to the main server 200 . The main server 200 is network-linked with the measurement unit 100 to receive and store the image captured by the measurement unit 100 .

In this case, the main server 200 may include a DB for storing and managing the photographed images and test results, and the test results may be transmitted from the determination unit 300 to be described later.

In this case, the battery cell defect inspection apparatus may further include a control unit 400 .

The control unit 400 controls the operation of the measurement unit 100 . Specifically, the control unit adjusts the X-ray application condition and the scanning (photographing) condition, and moves the photographing unit in a predetermined direction and angle to obtain an image or an image of a desired portion in the battery cell. In addition, the captured image or video may be reconstructed in three dimensions. In addition, the control unit transmits the image or video captured by the measurement unit to the main server.

The control unit 400 may be configured as a main PC, and the user manipulates the main PC to give a measurement instruction to the measurement unit, stores images or images captured by the measurement unit in the control unit, and organizes and classifies them. there is. That is, the control unit 400 does not analyze the image or the image.

At this time, the image or image taken by the measurement unit 400 is analyzed by the determination unit 300 . The determination unit 300 receives the image or image stored in the main server 200 and analyzes it to detect whether the electrode tab is disconnected or whether an overhang of the electrode assembly occurs. That is, in the present invention, since the image or image capturing and analysis of the image or image are performed in a separate space, the overall inspection process can be performed efficiently.

In addition, the determination unit 300 includes at least two or more sub-PCs (Sub-PCs, 310 , 320 , 330 , 340 ) that are network-linked with the main server 200 . Here, each of the sub-fishes 310 , 320 , 330 , and 340 work independently. The sub-PCs 310 , 320 , 330 , and 340 download an image or video from the main server 200 , and analyze the image or video using the analysis tool stored in the sub-PC 310 , 320 , 330 , 340 . . At this time, since a plurality of sub-fishes 310, 320, 330, and 340 are provided, one image or an image can be analyzed in a plurality of sub-fishes 310, 320, 330, and 340, and accordingly, the accuracy of the analysis is improved. improved, and the time required for analysis can be reduced.

Specifically, the two or more sub-fishes 310 , 320 , 330 , and 340 analyze the image or different parts of the image. When a plurality of battery cells are simultaneously inspected in the battery cell defect inspection system according to the present invention, each sub-fish 310 , 320 , 330 , 340 may inspect whether different battery cells are defective. Alternatively, each of the sub-fishes 310 , 320 , 330 , and 340 may inspect whether a defect occurs in different portions of the electrode tabs with respect to one battery cell. That is, the amount of work may be distributed as much as the number of each sub-fish 310 , 320 , 330 , 340 .

That is, the battery cell inspection system 10 according to the present invention separates the photographing operation and the analysis operation by placing the determination unit 300 for analyzing the image or image separately in the measuring unit 100 for photographing the image or image, Since the amount of work can be distributed by performing the analysis operation on the plurality of sub-fishes 310 , 320 , 330 , and 340 constituting the determination unit 300 , the accuracy of analysis can be improved and the time required for analysis can be shortened. it can be

In addition, the present invention provides a battery cell defect inspection method.

4 is a flowchart illustrating a procedure of a battery cell defect inspection method according to the present invention.

Referring to FIG. 4 , the battery cell defect inspection method according to the present invention includes: photographing an image or an image of an electrode tab portion in a battery cell through a measuring unit (S10); storing the image or video in a main server (S20); transmitting an image or video stored in the main server to two or more sub-PCs network-linked with the main server, respectively (S30); and analyzing the images or images stored in two or more sub-PCs, respectively, to detect whether the electrode tab is disconnected or whether an overhang of the electrode assembly occurs (S40).

The battery cell defect inspection method according to the present invention detects defects such as disconnection of an electrode tab portion or an overhang of an electrode assembly through CT imaging, thereby detecting all defects of a minute degree, thereby improving the reliability and accuracy of the inspection.

In addition, the battery cell defect inspection method according to the present invention can reduce the time required for defect detection by analyzing an image or image of an electrode tab portion using a plurality of sub-PCs linked to the main server and a network.

Hereinafter, each step of the battery cell defect inspection method according to the present invention will be described in detail.

Referring to FIGS. 2 and 3 together with FIG. 4 , first, with respect to the battery cell 110 to be measured, an image or an image of the electrode tab 113 portion is photographed through the measurement unit 100 . To this end, the battery cell 110 to be measured may be mounted on the jig 120 shown in FIG. 3 . In this case, since two or more battery cells can be simultaneously inspected as shown in FIG. 3 , it is possible to save imaging time.

When the battery cell 110 is mounted on the jig, an image or an image is captured. The image or the image may be taken using an X-ray computed tomography (CT) method. To this end, as shown in FIG. 3 , an image or an image of the electrode tab portion inside may be taken while scanning the battery cell 110 using the X-ray tube 131 .

In this way, when the battery cell 110 is photographed by the CT method, an image for each tomographic layer is obtained for the electrode tab portion in the battery cell, and the step of reconstructing the image in three dimensions may be further performed.

When an image or an image is obtained by the above process, it is transmitted to the main server 200 by the controller 400 and the image or image is stored in the main server 200 .

Subsequently, the image or video stored in the main server 200 is transmitted to the two or more sub-PCs 310 , 320 , 330 , 340 linked to the main server 200 in a network. Specifically, an operator who operates the sub-fishes 310 , 320 , 330 , and 340 may download an image or an image from the main server 200 .

When the image or image is transmitted to the sub-fish 310 , 320 , 330 , and 340 , it is analyzed to detect whether the electrode tab 113 is disconnected or whether the electrode assembly 111 has overhang. A battery cell in which disconnection or overhang is detected is determined to be defective. Specifically, the step of detecting whether the electrode tab is disconnected or an overhang occurs includes the process of visually analyzing the images or images stored in the sub-fish (310, 320, 330, 340) to determine the disconnection portion do.

5 is a schematic diagram illustrating a battery cell defect inspection method according to an embodiment of the present invention.

2 and 3 together with FIG. 5 , in the battery cell 110 , the electrode assembly 111 is accommodated in the battery case 112 , and electrode tabs 113 are disposed at both ends of the electrode assembly 111 . formed, and an electrode lead 114 is welded to the electrode tab 113 . Specifically, a first electrode tab 113a is formed at one end of the electrode assembly 111 , and a first electrode lead 114a is welded to the first electrode tab 113a. Similarly, a second electrode tab 113b is formed at the other end of the electrode assembly 111 , and a second electrode lead 114b is welded to the second electrode tab 113b.

In the battery cell defect inspection method according to the present invention, it is mainly detected whether the tab portion is defective. Specifically, in the image or image taken of the tab portion of the battery cell, cracks occur while scanning the image or image from one end of the first electrode tab 113a to the other end (eg, AA′ direction). It is checked whether overhang has occurred, or whether overhang has occurred by checking the arrangement of the first electrode tab 113a or the arrangement of the end portion of the electrode assembly 111 connected to the first electrode tab 113a. Similarly, it is checked whether cracks have occurred while scanning an image or an image from one end of the second electrode tab 113b to the other end direction (eg, BB′ direction), or the second electrode tab 113b It is checked whether an overhang has occurred by checking the arrangement or arrangement of the end portion of the electrode assembly 111 connected to the second electrode tab 113b. Such a process may be performed in each sub-PC, and an analysis tool installed in each sub-PC may be used.

6 is a photograph showing an analysis tool for detecting the occurrence of disconnection or overhang in the battery cell defect inspection method according to the present invention.

Referring to FIG. 6 , the analysis tool may display the inside of the battery cell for each cross-section along each direction. In FIG. 6, ② is a window displaying a cross-section of the battery cell when viewed from the same direction as in FIG. 5, and ① is a window displaying a cross-section of the battery cell viewed from the direction in which the electrode lead is drawn out. In the case of ③, the cross-section of the battery cell when viewed from the top is displayed. At this time, since the shapes shown in ① to ③ are adjusted to be interlocked with each other, it is possible to directly check whether a defect has occurred with the naked eye while looking at a cross-sectional view in three directions according to a specific position of the battery cell. For example, in the image displayed in ②, if any one point is selected, the cross-section of the corresponding point is displayed in ① and ③, while changing the point to be viewed in the image displayed in ② (for example, AA in FIG. ` direction), you can check whether a defect has occurred in the section indicated in ① and ③.

At this time, if defects such as disconnection are found, an image in which the disconnection occurred in the battery cell is expressed in three dimensions as shown in FIG. 7 can be obtained.

The process as described above may be equally performed in each sub-fish. As described above, since one image or image is analyzed from the plurality of sub-PCs constituting the determination unit, the accuracy of the examination may be improved and the examination time may be shortened.

Also, in another example, the image or different parts of the image may be analyzed in each sub-fish. That is, the inspection time can be shortened by distributing the amount of work as much as the number of each sub-fish.

Specifically, referring to FIGS. 2 and 3 together with FIG. 8 , the inspection section within the battery cell is divided into several compartments according to the number of sub-fishes 310, 320, 330, and 340, and then, each One sub-fish can be assigned to perform the test. For example, when the inspection is performed using four sub-fishes 310 , 320 , 330 , and 340 , one sub-fish 310 is a welded portion A ₁ of the first electrode tab 113a. ), and the other sub-fish 320 may be responsible for inspecting the portion A ₂ on which welding is not performed in the first electrode tab 113a. In addition, another sub-fish 330 is in charge of inspecting the welding portion B ₁ of the second electrode tab 113b, and the last sub-fish 340 is the second electrode tab 113b. It can be in charge of the inspection of the part (B ₂ ) that has not been welded in the middle. At this time, the test division assigned to each sub-fish can be appropriately adjusted.

In this case, in the step of detecting whether the electrode tab is disconnected or an overhang occurs, the process of analyzing the images or images stored in the sub-PC may be performed at the same time. For example, when the plurality of sub-fishes respectively analyze different parts of an image or an image as shown in FIG. 8 , such an analysis process may be performed at the same time.

Meanwhile, after the step of detecting whether the tap is disconnected or whether an overhang has occurred, the detection result is transmitted to the main server. At this time, when the results of image or video analysis in each sub-PC are transmitted to the main server, they are integrated into one to derive the final result. The operator determines whether the battery cell is defective from the final result.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the drawings disclosed in the present invention are for explanation rather than limiting the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these drawings. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back are used, but these terms are for convenience of explanation only, and may vary depending on the location of the object or the position of the observer. It is self-evident that it can

1: coil 2: magnetic field
3: Inspection object 4: Eddy current
10: Battery cell defect inspection system
100: measurement unit
110: battery cell 111: electrode assembly
112: battery case 113: electrode tab
113a: first electrode tab 113b: second electrode tab
114: electrode lead 114a: first electrode lead
114b: second electrode lead 120: jig
130: imaging unit 131: X-ray tube
132: detector 200: main server
300: judging unit
310, 320, 330, 340: sub fish
400: control unit

Claims (13)

In order to detect the tap disconnection of the battery cell, a measuring unit for taking an image or an image of the electrode tab portion in the battery cell;
a main server that is network-linked with the measurement unit to receive and store images captured by the measurement unit; and
and a determination unit that receives the image or image stored in the main server and analyzes the transmitted image or image to detect whether an electrode tab is disconnected or an overhang of the electrode assembly occurs,
The determination unit includes at least two or more sub-PCs that are network-linked with the main server.
According to claim 1,
The measurement unit,
a jig on which at least one battery cell is mounted; and
A battery cell defect inspection system including a photographing unit for photographing an image or an image of an electrode tab portion inside the battery cell.
3. The method of claim 2,
The imaging unit is a battery cell defect inspection system for taking an image using an X-ray computed tomography (CT) method.
According to claim 1,
Battery cell defect inspection system further comprising a control unit for controlling the operation of the measurement unit, and transmitting the image or image taken by the measurement unit to the main server.
According to claim 1,
The two or more sub-fish is a battery cell defect inspection system for analyzing different parts of the image or image.
Taking an image or an image of the electrode tab portion in the battery cell through the measuring unit;
storing the image or video in a main server;
transmitting an image or video stored in the main server to two or more sub-PCs connected to the main server in a network; and
A battery cell defect inspection method comprising the step of analyzing images or images stored in two or more sub-PCs, respectively, and detecting whether an electrode tab is disconnected or an overhang of an electrode assembly occurs.
7. The method of claim 6,
A battery cell defect inspection method that inspects two or more battery cells at the same time.
7. The method of claim 6,
The image or image is a battery cell defect inspection method that is taken using the X-ray computed tomography (CT, Computed Tomography) method.
9. The method of claim 8,
Battery cell defect inspection method further comprising the step of reconstructing the image or image into a three-dimensional image.
7. The method of claim 6,
The step of detecting whether the electrode tab is disconnected or whether an overhang occurs,
A battery cell defect inspection method comprising the step of visually analyzing each image or image stored in the sub-PC to confirm a disconnection occurrence portion.
11. The method of claim 10,
A battery cell defect inspection method in which different parts of the image or image are analyzed in each sub-fish.
11. The method of claim 10,
In the step of detecting whether the electrode tab is disconnected or whether an overhang occurs,
The process of analyzing each image or image stored in the sub-PC is a battery cell defect inspection method performed at the same time.
7. The method of claim 6,
After the step of detecting whether the electrode tab is disconnected or whether an overhang occurs,
Battery cell defect inspection method further comprising the step of transmitting the detection result to the main server.

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