Secondary battery manufacturing apparatus and secondary battery manufacturing method using the same

Abstract

A secondary battery manufacturing apparatus according to an example embodiment includes an analyzer configured to generate a merged image based on a plurality of images of a material sheet, the merged image including a plurality of portions of the material sheet. The analyzer is configured to determine a spatial frequency of periodic defects of the sheet of material based on the merged image.

Description

Technical Field

[0001] The present invention relates to a secondary battery manufacturing device and a secondary battery manufacturing method using the secondary battery manufacturing device. This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0037224 filed on March 22, 2023 and Korean Patent Application No. 10-2023-0102390 filed on August 4, 2023, and the entire contents of these Korean patent applications are incorporated herein by reference. Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged many times. Secondary batteries have been widely used as energy sources for various types of wireless devices such as mobile phones, laptop computers, and cordless vacuum cleaners. Recently, electrically driven hybrid electric vehicles (HEV) and battery electric vehicles (BEV) have become popular due to increased energy density and economies of scale. 、 As the manufacturing cost of battery electric vehicles (BEVs) has been dramatically reduced and the cruising range of BEVs has increased to the same level as that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to travel.

[0003] The basic unit of a secondary battery is a battery cell. According to the shape of the battery case, the battery cell is divided into a cylindrical battery in which the electrode assembly is built into a cylindrical metal case, a prismatic battery in which the electrode assembly is built into a prismatic metal case, and a pouch battery in which the electrode assembly is built into a pouch case of an aluminum laminate. Summary of the invention

[0004] Technical issues

[0005] The technical concept of the present invention is to provide a secondary battery manufacturing apparatus having improved reliability and a secondary battery manufacturing method using the secondary battery manufacturing apparatus.

[0006] Technical Solution

[0007] According to an example embodiment of the present invention, a secondary battery manufacturing device includes: a first roller and a second roller, the first roller and the second roller are configured to move a material sheet; a detector, the detector is configured to generate a plurality of images by photographing a plurality of portions of the material sheet, wherein some of the plurality of images include periodic defects; and an analyzer, the analyzer is configured to generate a merged image based on the plurality of images of the material sheet, the merged image including the plurality of portions of the material sheet, wherein the analyzer is configured to determine the spatial frequency of the periodic defects of the material sheet based on the merged image.

[0008] The merged image may be produced by merging the plurality of images in a first direction in which the sheet of material extends.

[0009] Each of the plurality of images may include an identification mark of the first roller or the second roller, and the analyzer may merge the plurality of images based on the identification mark.

[0010] The analyzer may prevent the portions of the sheet of material from repeating in the merged image based on the identifying mark.

[0011] The merged image may extend in a first direction in which the sheet of material extends and in a second direction perpendicular to the first direction.

[0012] Determining the spatial frequency of the periodic defect may include performing a Fourier transform on the merged image in the first direction to produce a frequency domain image of the merged image.

[0013] The Fourier transform may be a discrete Fourier transform.

[0014] The analyzer may be configured to determine the first roller or the second roller corresponding to a frequency having an intensity exceeding a threshold in the frequency domain image.

[0015] Performing Fourier transform on the merged image may include: dividing the merged image into a plurality of pixel arrays extending in the first direction and arranged in the second direction; and performing Fourier transform on each of the plurality of pixel arrays.

[0016] The Fourier transform may be a fast Fourier transform.

[0017] Performing Fourier transform on the merged image may include: generating a compressed image by adding together values ​​of pixels of the merged image that overlap in the second direction; and performing Fourier transform on the compressed image.

[0018] The secondary battery manufacturing apparatus may further include a pressing roller configured to press the material sheet.

[0019] The secondary battery manufacturing apparatus may further include a die coater configured to coat the material sheet with an electrode slurry.

[0020] According to an example embodiment, a secondary battery manufacturing device is provided. The secondary battery manufacturing device includes: a conveyor configured to move a material sheet; a detector configured to generate a plurality of images by photographing a plurality of portions of the material sheet; and an analyzer configured to generate a merged image based on the plurality of images of the material sheet, the merged image including the plurality of portions of the material sheet, wherein the analyzer is configured to analyze the spatial frequency of periodic defects of the material sheet based on the merged image.

[0021] The secondary battery manufacturing apparatus may further include a laser cutter configured to emit a laser beam toward the material sheet.

[0022] According to an example embodiment, a secondary battery manufacturing method is provided. The secondary battery manufacturing method includes: generating a plurality of images of a material sheet by photographing a plurality of portions of the material sheet, wherein the material sheet is moved by a first roller and a second roller; generating a merged image based on the plurality of images of the material sheet, the merged image including the plurality of portions of the material sheet; and performing frequency analysis on the merged image.

[0023] Each of the plurality of images may include an identification mark of the first roller or the second roller, and the plurality of images may be merged based on the identification mark.

[0024] The secondary battery manufacturing method may further include determining a spatial frequency of periodic defects of the material sheet based on performing a frequency analysis on the combined image.

[0025] The merged image may extend in a first direction in which the material sheet extends and in a second direction perpendicular to the first direction, and determining the spatial frequency of the periodic defects may include performing a Fourier transform on the merged image in the first direction to produce a frequency domain image of the merged image.

[0026] The Fourier transform may be a fast Fourier transform.

[0027] Performing Fourier transform on the merged image may include: dividing the merged image into a plurality of pixel arrays extending in the first direction and arranged in the second direction; and performing Fourier transform on each of the plurality of pixel arrays.

[0028] Performing Fourier transform on the merged image may include: generating a compressed image by adding together values ​​of pixels of the merged image that overlap in the second direction; and performing Fourier transform on the compressed image.

[0029] The secondary battery manufacturing method may further include determining the first roller or the second roller corresponding to the frequency having the intensity exceeding a threshold value in the frequency domain image as a cause of the periodic defect.

[0030] The secondary battery manufacturing method may further include generating an alarm including information related to a cause of the periodic defect.

[0031] According to an example embodiment, a secondary battery manufacturing method is provided. The secondary battery manufacturing method includes: generating multiple images of a material sheet by photographing multiple parts of the material sheet, wherein the material sheet is unwound from a first material roll by an unwinder and wound into a second material roll by a rewinder; generating a merged image based on the multiple images of the material sheet, the merged image including the multiple parts of the material sheet; performing Fourier transform on the merged image to generate a frequency domain image of the merged image; and determining the cause of the periodic defect of the material sheet based on the frequency domain image.

[0032] The frequency domain image may represent intensity-frequency distribution, and the cause of the periodic defect may be determined based on a comparison between the intensity of the frequency domain image and a threshold value.

[0033] Beneficial Effects

[0034] According to an exemplary embodiment of the present invention, in addition to detecting defects of a material sheet occurring during the manufacture of a secondary battery, the cause of a periodic defect of the material sheet can be identified by performing frequency analysis on an image of the material sheet including information related to the defect. Therefore, the factor causing the periodic defect can be quickly repaired, and the reliability of a secondary battery manufacturing device and a secondary battery manufacturing method using the secondary battery manufacturing device can be improved.

[0035] The effects that can be achieved from the exemplary embodiments of the present invention are not limited to the above-mentioned effects, and those skilled in the art to which the exemplary embodiments of the present invention belong will clearly derive and understand other effects not described herein from the following description. That is, those skilled in the art can derive from the exemplary embodiments of the present invention unexpected effects that are achieved when implementing the exemplary embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flowchart of a secondary battery manufacturing method according to example embodiments.

[0037] Figure 2 is a diagram for describing a secondary battery manufacturing apparatus according to example embodiments.

[0038] Figure 3 and Figure 4is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0039] Figure 5 is a flowchart of a secondary battery manufacturing method according to example embodiments.

[0040] Figure 6 is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0041] Figure 7 is a flowchart of a secondary battery manufacturing method according to example embodiments.

[0042] Figure 8 is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0043] Fig. 9 is a diagram for describing a secondary battery manufacturing apparatus according to other example embodiments.

[0044] Fig.10 is a diagram for describing a secondary battery manufacturing apparatus according to other example embodiments.

[0045] Fig.11 is a diagram for describing a secondary battery manufacturing apparatus according to other example embodiments.

[0046] Fig.12 is a diagram for describing a secondary battery manufacturing apparatus according to other example embodiments. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before describing the embodiments of the present invention, the terms or expressions used in the present specification and claims should not be interpreted as limited to those commonly understood or defined in commonly used dictionaries, but should be understood according to the meanings and concepts that match the present invention based on the principle that the inventor of the present application can appropriately define the terms or expressions to best explain the present invention.

[0048] Therefore, the embodiments described herein and the configurations illustrated in the accompanying drawings are merely embodiments of the present invention and do not reflect all technical concepts of the present invention. Therefore, it should be understood that various equivalents and modifications may exist to replace the configurations on the filing date of the present application.

[0049] Furthermore, in describing the present invention, when it is determined that a well-known configuration or function related to describing the present invention will obscure the subject matter of the present invention, the detailed description thereof may be omitted.

[0050] Because the embodiments of the present invention are provided to explain the present invention more comprehensively to those skilled in the art, the shapes, sizes, etc. of the components shown in the drawings may be exaggerated, omitted, or schematically shown for the sake of clarity. Therefore, the sizes or ratios of the components should not be understood as fully reflecting their actual sizes or ratios.

[0051] (First Embodiment)

[0052] Figure 1 is a flowchart of a secondary battery manufacturing method according to example embodiments.

[0053] Figure 2 is a diagram for describing a secondary battery manufacturing apparatus 100 according to an example embodiment.

[0054] Figure 3 and Figure 4 is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0055] Reference Figures 1 to 3 In P110, a plurality of images IMG1, IMG2, IMG3, IMG4, IMG5, IMG6, IMG7, IMG8, ​​and IMG9 (hereinafter, IMG1 to IMG9) may be generated. The plurality of images IMG1 to IMG9 may represent different portions of the material sheet SM1 processed by the secondary battery manufacturing apparatus 100. Each of the plurality of images IMG1 to IMG9 may be generated by the detector 180 of the secondary battery manufacturing apparatus 100.

[0056] According to example embodiments, the secondary battery manufacturing apparatus 100 may include an unwinder 110 ; a plurality of rollers 120 , 130 , 150 , and 160 ; pressing rollers 141 and 143 ; a rewinder 170 , a detector 180 , and an analyzer 190 .

[0057] The unwinder 110 may be configured to rotate the material roll RI1 to unwind the material sheet SM1 from the material roll RI1. The material roll RI1 and the material sheet SM1 may include materials processed by a roll-to-roll process. The material roll RI1 and the material sheet SM1 may include, but are not limited to, electrodes such as positive and negative electrodes, bag films, and separators.

[0058] The material sheet SM1 may be moved by the rotation drive of the plurality of rollers 120, 130, 150 and 160. The plurality of rollers 120, 130, 150 and 160 may be interposed between the unwinder 110 and the rewinder 170. The plurality of rollers 120, 130, 150 and 160 may have different diameters. Some of the plurality of rollers 120, 130, 150 and 160 may have different circumferences. Some of the plurality of rollers 120, 130, 150 and 160 may have the same circumference and diameter.

[0059] The plurality of rollers 120, 130, 150, and 160 may have synchronized circumferential speeds. That is, at least some of the plurality of rollers 120, 130, 150, and 160 may have different diameters, but the circumferential speeds of the plurality of rollers 120, 130, 150, and 160 may be substantially the same. Therefore, at least some of the plurality of rollers 120, 130, 150, and 160 may have different rotation frequencies.

[0060] The pressing rollers 141 and 143 may be interposed between the rollers 120 and 130 and the rollers 150 and 160. The diameter of each of the pressing rollers 141 and 143 may be greater than the diameter of each of the plurality of rollers 120, 130, 150, and 160. One of the pressing rollers 141 and 143 may rotate, while the other may stop. Each of the pressing rollers 141 and 143 may rotate in opposite directions or in the same direction.

[0061] Each of the pressing rollers 141 and 143 may apply pressure to the material sheet SM1 transferred by the rotation of the rollers 120 and 130. Therefore, a flattening process or a rolling process may be performed on the material sheet SM1.

[0062] The material sheet SM1 is stored in a wound state for a certain period of time, so the material sheet SM1 includes curling. The curling may cause reliability problems in the process of manufacturing a secondary battery, for example, in packaging an electrode assembly using a bag film. When a flattening process is performed on the material sheet SM1, the curling on the material sheet SM1 may be removed or reduced, thereby improving the reliability of manufacturing a secondary battery.

[0063] Here, the bag film PF may include an inner resin layer, a metal layer and an outer resin layer. The inner resin layer may have thermal adhesion, so it can seal the bag film PF. The inner resin layer may include, for example, a polyolefin-based material. The metal layer may include an alloy of iron, carbon, chromium and manganese; an alloy of iron, chromium and nickel; or aluminum.

[0064] Pouch film PF can be used to manufacture pouch-type battery cells. A battery cell is a basic unit of a lithium-ion battery, i.e., a secondary battery. A battery cell includes an electrode assembly, an electrolyte, and a housing. According to the configuration of the electrode assembly and the electrolyte, the battery cell is divided into a lithium-ion battery, a lithium-ion polymer battery, a lithium polymer battery, and the like. Due to the low possibility of electrolyte leakage and ease of manufacturing, the market share of lithium-ion polymer batteries in the field of secondary batteries is increasing.

[0065] The pouch type battery cell may include an electrode assembly and a pouch case in which the electrode assembly is built in. The pouch case may be provided through a forming process and a sealing process of a pouch film PF.

[0066] The thickness of the positive plate may be in the range of about 3 μm to about 500 μm. The positive plate may not cause chemical changes in the secondary battery finally manufactured, and may have high conductivity. The positive plate may include, for example, stainless steel, nickel, titanium, calcined carbon and aluminum. The positive plate may include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the positive plate may include a fine concave-convex structure to increase the adhesion of the active material. The positive plate may be in the form of a film, a sheet, a foil, a mesh, a porous body, a foam, a non-woven fabric, etc.

[0067] The thickness of the negative plate may be in the range of about 3 μm to about 500 μm. The negative plate may not cause chemical changes in the secondary battery finally manufactured, and may have high conductivity. The negative plate may include copper, stainless steel, aluminum, nickel, titanium, calcined carbon and aluminum-cadmium alloy. The negative plate may include stainless steel surface treated with carbon, nickel, titanium, silver, etc. The surface of the negative plate may include fine concave-convex structures to increase the adhesion of the active material. The negative plate may be in the form of a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0068] The positive electrode active material is a material that can cause an electrochemical reaction. The positive electrode active material can be a lithium transition metal oxide. For example, the positive electrode active material may include: a layered compound substituted with one or more transition metals, for example, lithium cobalt oxide (LiCoO 2 ) or lithium nickel oxide (LiNiO 2 ); lithium manganese oxide substituted with one or more transition metals; chemical formula LiNi 1-y M y O 2 (herein, M is Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga, and 0.01≤y≤0.7) represented by a lithium nickel-based oxide; represented by the chemical formula Li 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e Represented lithium nickel cobalt manganese composite oxide, for example, Li 1+ z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 or Li 1+zN i 0.4 Mn 0.4 Co 0.2 O 2(Here, -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 is Al, Mg, Cr, Ti, Si or Y, and A is F, P or Cl); or a olivine-based lithium metal phosphate represented by the chemical formula Li 1+x M 1-y M' y PO 4-z X z (Here, M is a transition metal, more specifically, Fe, Mn, Co or Ni, M' is Al, Mg or Ti, X is F, S or N, -0.5 ≤ x ≤ +0.5, 0 ≤ y ≤ 0.5, and 0 ≤ z ≤ 0.1).

[0069] For example, the negative electrode active material may include, for example, carbon such as non-graphitized carbon or graphitic carbon. The negative electrode active material may include, for example, metals such as Li x Fe 2 O 3 (0 ≤ x ≤ 1), LixWO 2 (0 ≤ x ≤ 1), or Sn x Me 1-x Me' y O z (Here, Me is Mn, Fe, Pb or Ge, Me' is Al, B, P, Si, a Group I element, a Group II element or a Group III element in the periodic table, or a halogen, 0 < x ≤ 1, 1 ≤ y ≤ 3, and 1 ≤ z ≤ 8). The negative electrode active material may include, for example, lithium metal, lithium alloys, silicon-based alloys and tin-based alloys. The negative electrode active material may include, for example, metal oxides such as 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 , or Bi 2 O 5 . For example, the negative electrode active material may include conductive polymers such as polyacetylene, Li-Co-Ni-based materials, etc.

[0070] The roller pressing process is a process of pressing the electrode plate coated with the active material to flatten and thin the surface of the electrode of the secondary battery. By performing the roller pressing process, the bonding force between the surface of the electrode plate and the active material can be enhanced. Since the bonding force between the surface of the electrode plate and the active material is enhanced, the movement of lithium ions of the electrode can be promoted, thereby improving the output and performance of the secondary battery finally manufactured.

[0071] The material sheet SM1 transferred by the rollers 150 and 160 may be wound by the rewinder 170. A material roll RO1 may be provided by winding the material sheet SM1.

[0072] The detector 180 may be configured to detect the appearance of the material sheet SM1. The detector 180 may be configured to detect the appearance of the material sheet SM1 in a non-contact manner similar to an image-based visual inspection device. The detector 180 may include one or more cameras. The detector 180 may be configured to determine defects of multiple parts of the material sheet SM1, such as foreign matter, stains, surface defects, scratches, dents, perforations, protrusions, depressions, core scratches, and non-core scratches, based on multiple images IMG1 to IMG9 captured from one or more cameras. The detector 180 may be configured to determine the uniformity of the distribution of the coating layer including the active material and the adhesive. The detector 180 may be configured to determine the positions of the defects D1, D2, and D3 in the multiple images IMG1 to IMG9 based on the two-dimensional (2D) light intensity profiles (or 2D reflection profiles) of the multiple images IMG1 to IMG9.

[0073] The analyzer 190 may be configured to analyze the results of the detection performed by the detector 180. More specifically, the analyzer 190 may generate a merged image MIMG in P120, perform frequency analysis on the merged image MIMG in P130, determine the spatial frequency of the periodic defect in P140, and determine the cause of the periodic defect in P150.

[0074] The analyzer 190 may be a computing device such as a workstation computer, a desktop computer, a laptop computer, or a tablet computer. The analyzer 190 may be configured as a separate hardware component or a separate software included in each hardware component. The analyzer 190 may be a simple controller, a microprocessor, a complex processor such as a CPU or a GPU, a processor configured by software, dedicated hardware, or firmware. The analyzer 190 may be implemented, for example, by a general-purpose computer or application-specific hardware such as a digital signal processor (DSP), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC).

[0075] According to some embodiments, the operation of the analyzer 190 described below may be implemented by instructions stored in a machine-readable medium that can be read and executed by one or more processors. Here, a machine-readable medium may include any mechanism for storing and / or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include a read-only memory (ROM), a random access memory (RAM), a disk storage medium, an optical storage medium, a flash memory device, an electrical, optical, acoustic or other type of radio signal (e.g., a carrier wave, an infrared signal, a digital signal, etc.) and other signals.

[0076] The firmware, software, routines, and instructions may also be configured to perform the above operations of the analyzer 190 or the processing to be described below. However, the above description is provided only for the convenience of description, and it should be understood that the above operations of the analyzer 190 may be performed by a computing device, a processor, a controller, or other devices for executing firmware, software, routines, instructions, etc.

[0077] Afterwards, in P120, a merged image MIMG may be generated. The analyzer 190 may be configured to merge the plurality of images IMG1 to IMG9 to generate a merged image MIMG. Each of the plurality of images IMG1 to IMG9 may extend in the X-axis direction and the Y-axis direction. The X-axis direction may be the direction in which the material piece SM1 extends. The Y-axis direction may be the direction in which the material piece SM1 moves. The Y-axis direction may be substantially perpendicular to the X-axis direction. The Y-axis direction may be the width direction of the material piece SM1. Each of the plurality of images IMG1 to IMG9 may correspond to the field of view of the detector 180 and may therefore include a portion of the material piece SM1. The analyzer 190 may provide a merged image MIMG obtained by connecting the plurality of images IMG1 to IMG9 in the X-axis direction.

[0078] Each of the plurality of images IMG1 to IMG9 may represent defects D1, D2 and D3 of the material sheet SM1. Therefore, the merged image MIMG may also include defects D1, D2 and D3.

[0079] In the merged image MIMG, each of the defects D1, D2, and D3 may be repeated periodically. In the merged image MIMG, the defects D1, D2, and D3 may be repeated in the X-axis direction at a certain spatial periodic interval. Therefore, each of the defects D1, D2, and D3 may be called a periodic defect.

[0080] For example, defect D1 may be repeated at intervals of spatial period T1, defect D2 may be repeated at intervals of spatial period T2, and defect D3 may be repeated at intervals of spatial period T3. Spatial periods T1, T2, and T3 may be different from each other. Spatial period T1 may be shorter than spatial period T2. Spatial period T2 may be shorter than spatial period T3.

[0081] Each of the spatial periods T1, T2, and T3 may correspond to a spatial frequency defined as its reciprocal. The unit of the spatial periods T1, T2, and T3 may be m, or the spatial periods T1, T2, and T3 may be standardized dimensionless quantities. Therefore, the unit of the spatial frequency may be 1 / m, or the spatial frequency may be a standardized dimensionless quantity. For example, when the spatial period T1 is about 1 / 2 [m], the spatial period T2 is about 2 [m], and the spatial period T3 is about 4 [m], the spatial frequency corresponding to the spatial period T1 may be about 2 [m]. -1 ], the spatial frequency corresponding to the spatial period T2 may be approximately 1 / 2 [m -1 ], and the spatial frequency corresponding to the spatial period T3 may be about 1 / 4 [m -1 ].

[0082] Next, refer to Figures 1 to 4 , in P130, a frequency analysis may be performed on the merged image MIMG. The merged image MIMG may include a plurality of pixels in the X-axis direction and the Y-axis direction. The defects D1, D2, and D3 may be represented in the form of coordinates according to the positions of the pixels of the merged image MIMG. Here, the positions of the pixels may be displayed using a local coordinate system limited to each of the plurality of images IMG1 to IMG9 or a global coordinate system common to the entire merged image MIMG.

[0083] In the merged image MIMG, the value of a pixel having defects D1, D2, D3 may be, for example, 1, and the value of a pixel without defects D1, D2, D3 may be, for example, 0. The values ​​of the pixels are only non-limiting examples, and each pixel may be given an arbitrary value indicating the presence or absence of defects D1, D2, and D3.

[0084] In this example, a compressed image CIMG may be generated for frequency analysis of the merged image MIMG. The compressed image CIMG may be generated by adding together the values ​​of pixels overlapping in the Y-axis direction. Thus, the compressed image CIMG may include the same number of pixels as the merged image MIMG in the X-axis direction, and include fewer pixels (e.g., one pixel) than the merged image MIMG in the Y-axis direction. The analyzer 190 may be configured to perform a Fourier transform on the compressed image CIMG in the X-axis direction.

[0085] exist Figure 3In the example, there are no overlapping defects in the Y-axis direction, so the value of the pixel overlapping with each of the defects D1, D2, and D3 can be 1. Figure 3 Unlike shown in , when the merged image MIMG includes additional defects overlapping some of the defects D1 , D2 , and D3 , the values ​​of the pixels of the compressed image CIMG corresponding to the additional defects may be 2 or more.

[0086] The Fourier transform performed on the compressed image CIMG may be a discrete Fourier transform such as a fast Fourier transform. The Fourier transform performed on the compressed image CIMG may be a short time Fourier transform. The Fourier transform in P130 may provide Figure 4 The intensity-spatial frequency diagram shown in Figure 4 The intensity-spatial frequency graph shown in may be referred to as a frequency domain image.

[0087] Next, in P140, the spatial frequency of the periodic defect may be determined. The spatial frequency of the periodic defect may be a value of the spatial frequency that exceeds a critical intensity in the frequency domain image. For example, Figure 4 , the intensities corresponding to the spatial frequencies f1, f2, and f3 exceed the threshold CP, so the spatial frequencies f1, f2, and f3 may each be the spatial frequency of a periodic defect.

[0088] When determining the spatial frequency of periodic defects, signals with an intensity less than or equal to the threshold CP can be regarded as noise. In addition, signals with a value less than the lower frequency limit fc1 or greater than or equal to the upper frequency limit fc2 can be treated as noise because there is no element of the secondary battery manufacturing equipment with the corresponding spatial frequency.

[0089] Thereafter, in P150, the cause of the periodic defect may be determined. Determining the cause of the periodic defect may include calculating spatial periods T1, T2, and T3 based on spatial frequencies f1, f2, and f3. According to example embodiments, spatial periods T1, T2, and T3 may be inverses of spatial frequencies f1, f2, and f3.

[0090] Determining the cause of the periodic defect may include determining a roller having a period similar to the spatial periods T1, T2, and T3 among the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143. Here, the period similar to the spatial periods T1, T2, and T3 should be understood to mean a period within a range set according to the spatial periods T1, T2, and T3 calculated from the spatial frequencies f1, f2, and f3. The range set according to the spatial periods T1, T2, and T3 includes systematic errors, negligent errors, and accidental errors that inevitably occur in the calculation of the spatial periods T1, T2, and T3. The range set according to each of the spatial periods T1, T2, and T3 is a range including the spatial periods T1, T2, and T3, and may include an upper limit value greater than each of the spatial periods T1, T2, and T3 and a lower limit value smaller than each of the spatial periods T1, T2, and T3.

[0091] According to example embodiments, the spatial periods T1, T2, and T3 may correspond to characteristic lengths of the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143. According to example embodiments, the spatial periods T1, T2, and T3 may be the same as the circumference of some of the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143. In addition, multiples (e.g., two, three, or four) of the spatial periods T1, T2, and T3 may be the same as the circumference of some of the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143.

[0092] Therefore, an element (i.e., multiple rollers 120, 130, 150 and 160, and some of the pressing rollers 141 and 143) having a characteristic length (e.g., circumference) within a range set according to the spatial periods T1, T2 and T3, or having a characteristic length (e.g., circumference) within a range set according to multiples (e.g., two times, three times or four times) of the spatial periods T1, T2 and T3 may be determined as the cause of periodic defects.

[0093] In the roll-to-roll process, when the cause of the defect occurs in the plurality of rollers 120, 130, 150 and 160, and the pressing rollers 141 and 143, the cause of the defect causes repeated periodic defects D1, D2 and D3 in the material sheet SM1. Therefore, rapid detection and repair of the periodic defects D1, D2 and D3 are necessary to improve the yield of the secondary battery.

[0094] The secondary battery manufacturing apparatus 100 and the secondary battery manufacturing method using the secondary battery manufacturing apparatus 100 according to the example embodiment can determine the occurrence of periodic defects D1, D2, and D3, and the elements of the secondary battery manufacturing apparatus 100 that are the causes of the periodic defects D1, D2, and D3 in real time. In particular, even defects that occur at long intervals (i.e., defects with a long characteristic length), such as defects caused by the pressing rollers 141 and 143, can determine the occurrence of periodic defects and their causing factors. Therefore, the yield and reliability of manufacturing secondary batteries can be improved.

[0095] Afterwards, an alarm may be generated. The alarm may include information related to the occurrence and cause of periodic defects (i.e., elements of the secondary battery manufacturing equipment 100 that cause periodic causes). The alarm may notify the operator of the occurrence and cause of periodic defects. When the cause of the periodic defect is determined in P150, the analyzer 190 may be configured to generate a signal for generating an alarm that notifies the operator of the cause of the periodic defect. In addition, the analyzer 190 may generate an interrupt signal for stopping the operation of the element of the secondary battery manufacturing equipment 100. The interrupt signal may be transmitted from the analyzer 190 to a controller (e.g., a programmable logic controller (PLC, Programmable Logic Controller)) configured to control the elements of the secondary battery manufacturing equipment 100. Therefore, it is possible to prevent additional defects from occurring in the material sheet SM1 due to periodic defects.

[0096] (Second Embodiment)

[0097] Figure 5 is a flowchart of a secondary battery manufacturing method according to example embodiments.

[0098] Figure 6 is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0099] In addition to P131, which performs frequency analysis on the merged image, Figure 5 The method is the same as above Figures 1 to 4 The method described is roughly the same. Figure 2 The secondary battery manufacturing apparatus 100 performs Figure 5 method.

[0100] Reference Figure 2 , Figure 5 and Figure 6 , the frequency analysis performed on the merged image in P131 may include performing the frequency analysis on the merged image without generating the compressed image CIMG (see Figure 3), the frequency analysis is directly performed on the merged image MIMG in the case of . According to an example embodiment, the analyzer 190 may divide the merged image MIMG into a plurality of pixel arrays PA1, PA2, ..., PAN-1, and PAN. According to an example embodiment, the analyzer 190 may perform Fourier transform on each of the plurality of pixel arrays PA1, PA2, ..., PAN-1, and PAN of the merged image MIMG.

[0101] Each of the plurality of pixel arrays PA1, PA2, ..., PAN-1, and PAN may include the same number of pixels as the merged image MIMG in the X-axis direction. Each of the plurality of pixel arrays PA1, PA2, ..., PAN-1, and PAN may include fewer pixels (e.g., one pixel) than the merged image MIMG in the Y-axis direction. Each of the plurality of pixel arrays PA1, PA2, ..., PAN-1, and PAN may be arranged in the Y-axis direction.

[0102] Therefore, in addition to determining the cause of the periodic defect among the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143, determining the cause of the periodic defect in P150 may include determining the Y-axis direction coordinate of the cause of the periodic defect among the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143. Therefore, the plurality of rollers 120, 130, 150, and 160, and the pressing rollers 141 and 143 may be quickly repaired.

[0103] (Third Embodiment)

[0104] Figure 7 is a flowchart of a secondary battery manufacturing method according to an embodiment.

[0105] Figure 8 is a diagram for describing a method of manufacturing a secondary battery according to example embodiments.

[0106] In addition to P121, which performs frequency analysis on the merged image, Figure 7 The method is the same as above Figures 1 to 4 The method described is roughly the same. Figure 2 The secondary battery manufacturing apparatus 100 performs Figure 7 method.

[0107] Reference Figure 2 , Figure 7 and Figure 8, a plurality of images IMG1', IMG2', IMG3', IMG4', IMG5', IMG6', IMG7', IMG8' and IMG9' (hereinafter, IMG1' to IMG9') may include overlapping areas OV1, OV2, OV3, OV4, OV5, OV6, OV7 and OV8 (hereinafter, OV1 to OV8). More specifically, the overlapping area OV1 may be included in each of images IMG1 and IMG2, the overlapping area OV2 may be included in each of images IMG2 and IMG3, the overlapping area OV3 may be included in each of images IMG3 and IMG4, the overlapping area OV4 may be included in each of images IMG4' and IMG5', the overlapping area OV5 may be included in each of images IMG5' and IMG6', the overlapping area OV6 may be included in each of images IMG6' and IMG7', the overlapping area OV7 may be included in each of images IMG7' and IMG8', and the overlapping area OV8 may be included in each of images IMG8' and IMG9'.

[0108] The frequency of capturing the plurality of images IMG1' to IMG9' by the detector 180 may be synchronized with the conveying speed of the material sheet SM1 so that the overlapped areas OV1 to OV8 may be minimized. When the overlapped areas OV1 to OV8 are not corrected, the spatial periods of the defects D1, D2 and D3 may be distorted due to the overlapped areas OV1 to OV8.

[0109] According to example embodiments, in addition to a portion of the material sheet SM1, the plurality of images IMG1' to IMG9' may further include a plurality of rollers 120, 130, 150, and 160, and a driving shaft DS that presses one of the rollers 141 and 143. The driving shaft DS may include an identification mark IM, and thus the plurality of images IMG1' to IMG9' may include the identification mark IM. The analyzer 190 may be configured to determine the overlapping areas OV1 to OV8 based on the size and shape of the identification mark IM on the plurality of images IMG1' to IMG9'.

[0110] According to an example embodiment, in P121, the analyzer 190 may be configured to prevent duplication of overlapping regions OV1 to OV8 during generation of the merged image MIMG. Therefore, it is possible to prevent distortion of the spatial frequency of periodic defects caused by the overlapping regions OV1 to OV8, and improve the reliability of the secondary battery manufacturing apparatus 100 and the secondary battery manufacturing method using the secondary battery manufacturing apparatus 100.

[0111] (Fourth Embodiment)

[0112] Fig. 92 is a diagram for describing a secondary battery manufacturing apparatus 200 according to other example embodiments.

[0113] Reference Fig. 9 The secondary battery manufacturing apparatus 200 may be a coater device. The secondary battery manufacturing apparatus 200 may include an unwinder 210 , a plurality of rollers 220 and 240 , die coaters 231 and 233 , a rewinder 250 , a detector 260 , and an analyzer 270 .

[0114] The unwinder 210 may be configured to rotate the material roll RI2 to unwind the material sheet SM2 from the material roll RI2. The material roll RI2 and the material sheet SM2 may include a positive electrode plate or a negative electrode plate.

[0115] The material sheet SM2 may be moved by the rotation drive of the plurality of rollers 220 and 240. The plurality of rollers 220 and 240 may be interposed between the unwinder 210 and the rewinder 250. The plurality of rollers 220 and 240 may have different diameters. The plurality of rollers 220 and 240 may have different circumferences. Some of the plurality of rollers 220 and 240 may have the same circumference and diameter.

[0116] The plurality of rollers 220 and 240 may have synchronized circumferential speeds. That is, at least some of the plurality of rollers 220 and 240 may have different diameters, but the circumferential speeds of the plurality of rollers 220 and 240 may be substantially the same. Therefore, at least some of the plurality of rollers 220 and 240 may have different rotation frequencies.

[0117] The die coaters 231 and 233 may be interposed between the roller 220 and the roller 240. Each of the die coaters 231 and 233 may be configured to discharge the electrode slurry. The material sheet SM2 may be coated with the electrode slurry discharged by the die coaters 231 and 233.

[0118] The material sheet SM2 transferred by the roller 240 may be wound by the rewinder 250. The material roll RO2 may be provided to wind up the material sheet SM2.

[0119] The detector 260 may be configured to detect the appearance of the material sheet SM2. The detector 260 and the analyzer 270 may be respectively Figure 2 The detector 180 and the analyzer 190 are substantially the same. According to an example embodiment, the analyzer 270 may be configured to perform Figure 1 , Figure 5 and Figure 7 method.

[0120] (Fifth Embodiment)

[0121] Fig.10 is a diagram for describing a secondary battery manufacturing apparatus 300 according to other example embodiments.

[0122] Reference Fig.10 , the secondary battery manufacturing equipment 300 may be a slitting device.

[0123] According to example embodiments, the secondary battery manufacturing apparatus 300 may include an unwinder 310 , a plurality of rollers 320 , 330 , 340 , and 360 , a slitter 350 , a rewinder 370 , a detector 380 , and an analyzer 390 .

[0124] The unwinder 310 may be configured to rotate the material roll RI3 to unwind the material sheet SM3 from the material roll RI3. The material roll RI3 and the material sheet SM3 may include a positive electrode plate or a negative electrode plate.

[0125] The material sheet SM3 may be moved by the rotation drive of the plurality of rollers 320, 330, 340 and 360. The plurality of rollers 320, 330, 340 and 360 may be interposed between the unwinder 310 and the rewinder 370. The plurality of rollers 320, 330, 340 and 360 may have different diameters. The plurality of rollers 320, 330, 340 and 360 may have different circumferences. Some of the plurality of rollers 320, 330, 340 and 360 may have the same circumference and diameter.

[0126] The plurality of rollers 320, 330, 340, and 360 may have synchronized circumferential speeds. That is, at least some of the plurality of rollers 320, 330, 340, and 360 may have different diameters, but the circumferential speeds of the plurality of rollers 320, 330, 340, and 360 may be substantially the same. Therefore, at least some of the plurality of rollers 320, 330, 340, and 360 may have different rotation frequencies.

[0127] The slitter 350 may be interposed between the rollers 320, 330, and 340 and the roller 360. The slitter 350 may cut the material sheet SM3 to provide a plurality of material sheets SM3'. The width of each of the plurality of material sheets SM3' may be smaller than the width of the material sheet SM3. Although the material sheet SM3 is shown as being divided into two material sheets SM3' for ease of explanation, the technical concept of the present invention should not be understood as being limited thereto in any sense. A person of ordinary skill in the art will be able to easily derive an embodiment in which the material sheet SM3 is divided into three or more material sheets SM3' based on the above description.

[0128] The material sheet SM3 transferred by the roller 360 may be wound by the rewinder 370. The material roll RO3 may be provided to wind up the material sheet SM3'.

[0129] The detectors 380 may be configured to detect the appearance of the material sheet SM3'. Each detector 380 may be connected to Figure 2 The detector 180 is substantially the same as that of the analyzer 390, and the analyzer 390 may be Figure 2According to an example embodiment, the analyzer 390 may be configured to perform Figure 1 , Figure 5 and Figure 7 method.

[0130] (Sixth Embodiment)

[0131] Fig.11 is a diagram for describing a secondary battery manufacturing apparatus 400 according to other example embodiments.

[0132] According to example embodiments, the secondary battery manufacturing apparatus 400 may include a driving wheel 410 , a conveyor belt 420 , a notching device 430 , detectors 441 and 443 , and an analyzer 450 .

[0133] The conveyor belt 420 may convey the material sheet SM4 by the rotation of the driving wheel 410. The material sheet SM4 may be a diaphragm, a bag film, or an electrode.

[0134] The cutting device 430 may be on the conveyor belt 420. According to an example embodiment, the cutting device 430 may be a laser cutter configured to emit a laser beam onto the material sheet SM4, but is not limited thereto. The cutting device 430 may include a punch cutter. The cutting device 430 may remove an uncoated portion of the material sheet SM4 except for a portion for a tab. Since the material sheet SM4 is processed by the cutting device 430, a material SM4' separated from the material sheet SM4 may be provided. The separated material SM4' may have a size and shape suitable for use in an electrode of a battery cell.

[0135] According to an example embodiment, the detector 441 may be configured to detect the appearance of the material sheet SM4. The detector 443 may be configured to detect the separated material SM4'. The detectors 441 and 443 may each be connected to Figure 2 The detector 180 is substantially the same as that of the embodiment of the present invention, and the analyzer 450 can be used with Figure 2 According to an example embodiment, the analyzer 450 may be configured to perform Figure 1 , Figure 5 and Figure 7 method.

[0136] (Seventh Embodiment)

[0137] Fig.12 is a diagram for describing a secondary battery manufacturing apparatus 500 according to other example embodiments.

[0138] According to example embodiments, the secondary battery manufacturing apparatus 500 may include a driving wheel 510 , a conveyor belt 520 , a detector 530 , and an analyzer 540 .

[0139] The conveyor belt 520 may convey the material MM by the rotation of the driving wheel 510. The material MM may be a battery cell of a secondary battery.

[0140] The battery cell is a lithium-ion battery, ie, a basic unit of a secondary battery. The battery cell includes an electrode assembly, an electrolyte, and a case.

[0141] According to the shape of the battery case, the battery cell is classified into a cylindrical battery in which an electrode assembly is built in a cylindrical metal case, a prismatic battery in which an electrode assembly is built in a prismatic metal case, or a pouch-type battery in which an electrode assembly is built in a pouch case of an aluminum laminate sheet.

[0142] The electrode assembly included in the battery case includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. According to the form of the assembly, the electrode assembly can be divided into a jelly roll type electrode assembly or a stacked type electrode assembly. The jelly roll type electrode assembly is manufactured by winding the positive electrode, the negative electrode, and the separator interposed therebetween. The stacked type electrode assembly includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed therebetween stacked in sequence.

[0143] The positive electrodes may each include a positive electrode current collector and a positive electrode active material. The negative electrodes may each include a negative electrode current collector and a negative electrode active material.

[0144] According to example embodiments, the secondary battery manufacturing apparatus 500 may be configured to perform a battery assembly process. According to example embodiments, the secondary battery manufacturing apparatus 500 may be configured to perform one of an electrode stacking process, a bag cutting process, a bag forming process, an electrolyte injection process, a formation process, an aging process, and a degassing process.

[0145] In the electrode stacking process, the electrode assembly can be arranged by stacking the positive electrode, the negative electrode and the separator. In the bag cutting process, the bag film can be cut according to the standard requirements. In the bag forming process, the bag film can be formed in a shape suitable for accommodating the electrode assembly. In the electrolyte injection process, the electrolyte can be injected into the battery case. In the formation process, the battery cell can be initially charged and discharged. In the formation process, a solid electrolyte interface (SEI, Solid Electrolyte Interphase) layer can be formed. In the aging process, the battery can be stored in a controlled temperature and humidity environment for a certain period of time (for example, 30 minutes to 3 hours). In the degassing process, the air bag can be cut off after the electrolyte is injected to remove unnecessary gas.

[0146] According to an example embodiment, the detector 530 may be configured to detect the appearance of the material MM. The detector 530 may be configured to detect the appearance of the material MM. Figure 2 The detector 180 is substantially the same as that of the analyzer 540, and the analyzer 540 may be Figure 2 According to an example embodiment, the analyzer 540 may be configured to perform Figure 1 , Figure 5 and Figure 7 method.

[0147] The present invention has been described in more detail above with reference to the accompanying drawings, embodiments, etc. However, the configurations shown in the drawings or the embodiments described in this application are merely embodiments of the present invention and do not reflect all technical concepts of the present invention, and therefore it should be understood that various equivalents and modifications that may replace the configurations may exist on the filing date of this application.

Claims

1. A secondary battery manufacturing device, comprising: a first roller and a second roller, the first roller and the second roller configured to move a sheet of material; a detector configured to generate a plurality of images by photographing a plurality of portions of the sheet of material, wherein some of the plurality of images include periodic defects; as well as an analyzer configured to generate a merged image based on the plurality of images of the piece of material, the merged image including the plurality of portions of the piece of material, Wherein the analyzer is configured to determine a spatial frequency of the periodic defects of the material sheet based on the merged image. 2 . The secondary battery manufacturing apparatus according to claim 1 , wherein the merged image is produced by merging the plurality of images in a first direction in which the material sheet extends.

3. The secondary battery manufacturing apparatus according to claim 1, wherein each of the plurality of images includes an identification mark of the first roller or the second roller, and The analyzer merges the plurality of images based on the identification marker. 4 . The secondary battery manufacturing apparatus according to claim 3 , wherein the analyzer prevents the plurality of portions of the material sheet from being repeated in the merged image based on the identification mark.

5. The secondary battery manufacturing apparatus according to claim 1, wherein the combined image extends in a first direction in which the material sheet extends and in a second direction perpendicular to the first direction, and Determining the spatial frequency of the periodic defect includes performing a Fourier transform on the merged image in the first direction to generate a frequency domain image of the merged image. 6 . The secondary battery manufacturing apparatus according to claim 5 , wherein the Fourier transform is a discrete Fourier transform. 7 . The secondary battery manufacturing apparatus according to claim 5 , wherein the Fourier transform is a fast Fourier transform. 8 . The secondary battery manufacturing apparatus according to claim 5 , wherein the analyzer is configured to determine the first roller or the second roller corresponding to a frequency having an intensity exceeding a threshold value in the frequency domain image.

9. The secondary battery manufacturing apparatus according to claim 5, wherein performing Fourier transform on the merged image comprises: dividing the merged image into a plurality of pixel arrays extending in the first direction and arranged in the second direction; and A Fourier transform is performed on each of the plurality of pixel arrays.

10. The secondary battery manufacturing apparatus according to claim 5, wherein performing Fourier transform on the combined image comprises: generating a compressed image by adding together the values ​​of pixels of the merged image that overlap in the second direction; and A Fourier transform is performed on the compressed image. 11 . The secondary battery manufacturing apparatus of claim 1 , further comprising a pressing roller configured to press the material sheet. 12 . The secondary battery manufacturing apparatus of claim 1 , further comprising a die coater configured to coat the material sheet with an electrode slurry.

13. A secondary battery manufacturing device, comprising: a conveyor belt configured to move a sheet of material; a detector configured to generate a plurality of images by photographing a plurality of portions of the sheet of material; as well as an analyzer configured to generate a merged image based on the plurality of images of the piece of material, the merged image including the plurality of portions of the piece of material, Wherein the analyzer is configured to analyze the spatial frequency of periodic defects in the material sheet based on the merged image. 14 . The secondary battery manufacturing apparatus of claim 13 , further comprising a laser cutter configured to emit a laser beam toward the material sheet.

15. A method for manufacturing a secondary battery, comprising: generating a plurality of images of a sheet of material by photographing a plurality of portions of the sheet of material, wherein the sheet of material is moved by a first roller and a second roller; generating a merged image based on the plurality of images of the sheet of material, the merged image including the plurality of portions of the sheet of material; as well as A frequency analysis is performed on the merged image.

16. The secondary battery manufacturing method according to claim 15, wherein each of the plurality of images includes an identification mark of the first roller or the second roller, and The plurality of images are merged based on the identifying mark.

17. The secondary battery manufacturing method of claim 15, further comprising determining a spatial frequency of periodic defects of the material sheet based on performing a frequency analysis on the merged image.

18. The secondary battery manufacturing method according to claim 17, wherein the combined image extends in a first direction in which the material sheet extends and in a second direction perpendicular to the first direction, and Determining the spatial frequency of the periodic defect includes performing a Fourier transform on the merged image in the first direction to produce a frequency domain image of the merged image.

19. The secondary battery manufacturing method according to claim 18, wherein the Fourier transform is a fast Fourier transform.

20. The secondary battery manufacturing method according to claim 18, wherein performing Fourier transform on the merged image comprises: dividing the merged image into a plurality of pixel arrays extending in the first direction and arranged in the second direction; and A Fourier transform is performed on each of the plurality of pixel arrays.

21. The secondary battery manufacturing method according to claim 18, wherein performing Fourier transform on the merged image comprises: generating a compressed image by adding together the values ​​of pixels of the merged image that overlap in the second direction; and A Fourier transform is performed on the compressed image. 22 . The secondary battery manufacturing method according to claim 18 , further comprising determining a first roller or a second roller corresponding to a frequency having an intensity exceeding a threshold value in the frequency domain image as a cause of the periodic defect. 23 . The secondary battery manufacturing method according to claim 22 , further comprising generating an alarm including information related to a cause of the periodic defect.

24. A method for manufacturing a secondary battery, comprising: generating a plurality of images of a sheet of material by photographing a plurality of portions of the sheet of material, wherein the sheet of material is unwound from a first roll of material by an unwinder and is wound into a second roll of material by a rewinder; generating a merged image based on the plurality of images of the sheet of material, the merged image including the plurality of portions of the sheet of material; Performing Fourier transform on the merged image to generate a frequency domain image of the merged image; as well as Causes of periodic defects in the material sheet are determined based on the frequency domain image.

25. The secondary battery manufacturing method according to claim 24, wherein the frequency domain image represents intensity-frequency distribution, and The cause of the periodic defect is determined based on a comparison between the intensity of the frequency domain image and a threshold value.

Images