Method and device for manufacturing all-solid-state battery

Abstract

The present invention relates to a method for manufacturing an all-solid-state battery, and more particularly, to a method for manufacturing an all-solid-state battery in which a performance reduction factor of an all-solid-state battery is ascertained by non-destructive testing, the performance of a battery cell is predicted on the basis thereof, and a manufacturing process of the battery cell is evaluated.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for manufacturing an all-solid-state battery. Background Art

[0002] Nowadays, secondary batteries are used in a variety of fields, from small devices such as mobile phones, cameras, and laptop computers to large devices such as automobiles and power storage systems. As the application fields of secondary batteries expand, the requirements for improving battery safety and high performance are also increasing.

[0003] Compared with nickel-manganese batteries or nickel-cadmium batteries, the most widely used lithium secondary battery has the advantages of high energy density and large capacity per unit area. A lithium secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator. The electrolyte is a liquid electrolyte containing a flammable organic solvent, and lithium ions move between the positive electrode and the negative electrode through the electrolyte to achieve charge and discharge. The safety issues of lithium secondary batteries, such as fires and explosions caused by the leakage of the electrolyte, have been continuously concerned.

[0004] Recently, in order to improve the safety of such lithium secondary batteries, the attention to all-solid-state batteries has been increasing. The all-solid-state battery replaces the liquid electrolyte with a solid electrolyte and solidifies the internal materials of the battery. The all-solid-state battery has no risk of electrolyte leakage and does not require a separator, so the battery structure can be simplified, and it is expected to reduce the manufacturing cost and improve the productivity. In addition, compared with the liquid electrolyte, the solid electrolyte has a high density and a low molecular mobility, so a battery with a large energy capacity per unit size can be manufactured, and thus a large-capacity secondary battery for electric vehicles and the like can be realized.

[0005] The raw materials of the negative electrode, solid electrolyte, and positive electrode of the all-solid-state battery are in the form of solid powder. Generally, they are laminated in the form of a slurry to manufacture. At this time, pores may be generated inside each layer or foreign substances may be mixed in to cause defects. Since the solid electrolyte has no fluidity and these defects can limit the movement of lithium ions, the performance of the battery can be greatly reduced. Therefore, it is necessary to identify the defects based on the above-mentioned pores or foreign substances and propose solutions. Summary of the Invention

[0006] Technical problems to be solved by the present invention

[0007] The present invention provides a method and apparatus for manufacturing an all-solid-state battery, which can predict the performance by identifying the pores or foreign substances existing inside the all-solid-state battery, and can change the process conditions when the performance is not suitable.

[0008] Technical solution

[0009] One aspect of the present invention provides a method for manufacturing an all-solid-state battery, the method comprising: a battery cell manufacturing step of manufacturing a battery cell containing a solid electrolyte through a battery cell manufacturing unit; a first image acquisition step of performing radiography on the battery cell through an imaging unit to acquire a first image; a pressing step of uniformly pressing the battery cell through a pressing unit; a second image acquisition step of performing radiography on the pressed battery cell through the imaging unit to acquire a second image; an information detection step of processing the first image through a control unit to detect first non-active region information and processing the second image to detect second non-active region information; and a determination step of deriving the non-activity degree of the battery cell by using the first non-active region information or the second non-active region information through the control unit, and determining whether the battery cell is suitable by comparing the non-activity degree of the battery cell with a preset reference value.

[0010] Beneficial effects

[0011] The all-solid-state battery manufacturing method and apparatus according to an embodiment of the present invention can grasp the factors causing performance degradation of the all-solid-state battery through non-destructive testing, determine the performance of the battery cell based on this, and evaluate and change the manufacturing process of the battery cell. Description of the Drawings

[0012] Figure 1 is a block diagram for explaining an all-solid-state battery manufacturing apparatus according to an embodiment of the present invention.

[0013] Figure 2 is a flowchart briefly showing an all-solid-state battery manufacturing method according to an embodiment of the present invention.

[0014] Figure 3 is a conceptual diagram for explaining a method of detecting non-active region information through image processing.

[0015] Figure 4 is a conceptual diagram for explaining a method of distinguishing a non-active region based on pores and a non-active region based on foreign matter from an image and performing image processing.

[0016] Figure 5 is a diagram showing a case where the non-activity degree decreases when comparing the first image and the second image.

[0017] Figure 6 is a diagram showing a case where the non-activity degree increases when comparing the first image and the second image. Detailed Description of the Invention

[0018] One aspect of the present invention is to provide a method for manufacturing an all-solid-state battery, the method comprising: a battery cell manufacturing step of manufacturing a battery cell including a solid electrolyte through a battery cell manufacturing unit; a first image acquisition step of performing radiography on the battery cell through an imaging unit to acquire a first image; a pressing step of uniformly pressing the battery cell through a pressing unit; a second image acquisition step of performing radiography on the pressed battery cell through the imaging unit to acquire a second image; an information detection step of processing the first image through a control unit to detect first non-active region information and processing the second image to detect second non-active region information; and a determination step of deriving the non-activity degree of the battery cell by using the first non-active region information or the second non-active region information through the control unit, and determining whether the battery cell is suitable by comparing the non-activity degree of the battery cell with a preset reference value.

[0019] In addition, after the step of determining whether the battery cell is defective, the following steps may further be included: through the control unit, when it is determined that the battery cell is not suitable for the reference value, using the first non-active region information or the second non-active region information to change the manufacturing conditions or the uniform pressing conditions of the battery cell, so as to control the battery cell manufacturing unit or the pressing unit.

[0020] In addition, the step of controlling the battery cell manufacturing unit or the pressing unit may change the manufacturing conditions or the uniform pressing conditions of the battery cell by comparing the first non-active region information of the first image and the second non-active region information of the second image and according to the change rate of the non-activity degree of the battery cell before and after pressing.

[0021] In addition, the first non-active region information and the second non-active region information may be information including at least one of the brightness values, brightness distributions, number of pixels, pixel sizes, and pixel areas of the respective pixels of the first image and the second image.

[0022] In addition, in the step of determining whether the battery cell is suitable, the non-activity degree of the battery cell may be derived according to the following formula 1.

[0023] [Formula 1]

[0024] Non-activity degree (%) = [Area of the second non-active region (A2) / Total area inside the battery cell (A 总 (A total ))] * 100

[0025] In addition, the battery cell may be a single battery cell (mono-cell) or a stacked battery cell (stack-cell).

[0026] In addition, the imaging unit may be an X-ray device or a three-dimensional CT device.

[0027] On the other hand, the present invention provides a all-solid-state battery manufacturing apparatus, the apparatus comprising: a cell manufacturing unit for manufacturing a cell including a solid electrolyte; a pressing unit for uniformly pressing the cell; an imaging unit for radiographing the cell to obtain a first image or a second image; and a control unit for detecting first non-active region information by processing the first image, and detecting second non-active region information by processing the second image, deriving the non-activity degree of the cell using the first non-active region information or the second non-active region information, and determining whether the cell is suitable by comparing the non-activity degree of the cell with a preset reference value.

[0028] In addition, when it is determined that the cell is not suitable for the reference value, the control unit may use the first non-active region information or the second non-active region information to change the manufacturing conditions or the uniform pressing conditions of the cell, so as to control the cell manufacturing unit or the pressing unit.

[0029] In addition, when the control unit controls the cell manufacturing unit or the pressing unit, the manufacturing conditions or the uniform pressing conditions of the cell may be changed by comparing the first non-active region information of the first image and the second non-active region information of the second image and according to the change rate of the non-activity degree of the cell before and after pressing.

[0030] In addition, the first non-active region information and the second non-active region information may be information including at least one of the brightness values, brightness distributions, number of pixels, pixel sizes, and pixel areas of the respective pixels of the first image and the second image.

[0031] In addition, the step of determining whether the cell is suitable may derive the non-activity degree of the cell according to the following formula 1.

[0032] [Formula 1]

[0033] Non-activity degree (%) = [Area of the second non-active region (A2) / Total area inside the cell (A total )] * 100

[0034] In addition, the cell may be a single cell (mono-cell) or a stacked cell (stack-cell).

[0035] In addition, the imaging unit may be an X-ray device or a three-dimensional CT device. Specific embodiments

[0037] Hereinafter, with reference to the accompanying drawings, the following embodiments will be described in detail. When described with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals, and the description thereof will be omitted.

[0038] This embodiment can be transformed in various ways, and specific embodiments are shown in the accompanying drawings and described in detail in the detailed description. The effects, features, and methods for implementing them can be made clear by referring to the content described in detail later in connection with the accompanying Figure 1 drawings. However, this embodiment is not limited to the embodiments disclosed below and can be implemented in various forms.

[0039] In the following embodiments, terms such as "first" and "second" are used for the purpose of distinguishing one component from other components and do not have a limiting meaning.

[0040] In the following embodiments, unless otherwise clearly stated herein, a singular quantity expression includes a plural quantity expression.

[0041] In the following embodiments, terms such as "comprising" or "having" mean the presence of the features or components described in the specification and do not preclude the additional possibility of one or more other features or components.

[0042] In the following embodiments, when referring to a part such as a unit, region, component, etc. being located on or above another part, it includes not only the case of being directly located on another part but also the case where there are other units, regions, components, etc. therein.

[0043] In the following embodiments, unless otherwise clearly stated herein, terms such as "connected" or "coupled" do not necessarily refer to a direct and / or fixed connection or coupling between two components and do not exclude the presence of other components between the two components.

[0044] It means the presence of the features or components described in the specification and does not preclude the additional possibility of one or more other features or components.

[0045] For ease of explanation, the sizes of the components in the drawings may be exaggerated or reduced. For example, for ease of explanation, the sizes and thicknesses of the components shown in the drawings are arbitrarily shown, so the following embodiments are not necessarily limited to what is shown.

[0046] In the present invention, the term "cell" refers to a all-solid-state battery, and it includes a negative electrode containing a negative electrode active material, a positive electrode containing a positive electrode active material, and a solid electrolyte disposed between the negative electrode and the positive electrode.

[0047] The term "active material" refers to a substance that can generate electric energy through a chemical reaction. As lithium ions are inserted into or detached from the active material, an electrochemical oxidation reaction or reduction reaction will occur.

[0048] The term "activity" means that the movement of electrons or ions causes the cell to be charged or discharged.

[0049] The term "inactive region" refers to a region that is electrochemically inactive, which means that through at least one pore or foreign matter inside the cell, the density of a part inside the cell decreases, resulting in a deviation in the ionic conductivity of the solid electrolyte.

[0050] The term "active region" refers to a region that is electrochemically active, which means the remaining region inside the cell except for the inactive region.

[0051] The term "inactivity degree" is an approximate value of the performance of the cell, which refers to the degree or proportion including the inactive region of the cell.

[0052] The term "pixel" refers to the smallest unit that constitutes an image. The smaller the pixel size, the higher the resolution ability of the image, and the more the number of pixels included in the same range, the higher the resolution.

[0053] The term "voxel" is the value of a regular grid unit in three-dimensional space, which refers to the smallest unit that constitutes a three-dimensional image.

[0054] Figure 1 It is a block diagram of a manufacturing apparatus for all-solid-state batteries for explaining an embodiment of the present invention.

[0055] Refer to Figure 1 , the all-solid-state battery manufacturing apparatus 1 according to an embodiment of the present invention may include a cell manufacturing unit 10, a pressing unit 20, an imaging unit 30, a recovery unit 40, and a control unit 50.

[0056] The cell manufacturing unit 10 may be arranged to manufacture a cell containing a solid electrolyte. The cell is an all-solid-state battery, which may include a negative electrode, a positive electrode, and a solid electrolyte.

[0057] In the cell manufacturing unit 10, the cell may be manufactured by disposing the solid electrolyte between the negative electrode and the positive electrode.

[0058] Specifically, the cell may be manufactured by sequentially laminating the negative electrode, the solid electrolyte, and the positive electrode to form a layered structure.

[0059] The negative electrode may include a negative electrode current collector and a negative electrode active material layer formed on the surface of the negative electrode current collector. The negative electrode active material layer may include a negative electrode active material, and the negative electrode active material may be composed of lithium metal.

[0060] The negative electrode active material layer may be formed by laminating a lithium metal thin film on the surface of the current collector, or by electroplating lithium metal on the surface of the current collector, or by chemical or physical vapor deposition.

[0061] Any negative electrode active material that can be commonly used in the negative electrode of a lithium secondary battery can be used. For example, carbon such as non-graphitizable carbon and graphite-based carbon (natural graphite, artificial graphite) can be used; Li x Fe2O3 (0 ≤ x ≤ 1), Li x WO2 (0 ≤ x ≤ 1), Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements in Group 1, Group 2, Group 3 of the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8), etc. metal composite oxides; lithium metal, lithium alloy, silicon-based alloy, tin-based alloy, SnO, SnO2, PbO, PbO2, Sb2O3, GeO, GeO2, Bi2O3, Bi2O4, etc. metal oxides, conductive polymers such as polyacetylene, Li-Co-Ni-based materials, titanium oxides, lithium titanium oxides, or combinations thereof, etc., but not limited thereto.

[0062] The positive electrode may include a positive electrode current collector and a positive electrode active material layer formed on the surface of the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, and the positive electrode active material may be composed of a sulfur compound.

[0063] Any positive electrode active material that can be commonly used in the positive electrode of a lithium secondary battery can be used. For example, the positive electrode active material may be a lithium oxide. Specifically, the positive electrode active material may use layered compounds such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals, lithium manganese oxides such as LiMnO3, LiMn2O3, lithium copper oxide, vanadium oxides such as LiV3O8, LiFe3O4, V2O5, Cu2V2O7, Ni-site type lithium nickel oxide, lithium manganese composite oxide, sulfur compound, or combinations thereof, etc., but not limited thereto.

[0064] The negative electrode current collector and the positive electrode current collector may be provided in a plate shape with a specified thickness, and may be provided in a manner that can support the negative electrode active material and the positive electrode active material respectively.

[0065] Generally, copper metal is widely used in the negative electrode current collector, and aluminum metal is widely used in the positive electrode current collector. However, it is not limited thereto, and any material that does not cause chemical changes in the battery cell and has conductivity can be used.

[0066] As needed, the negative electrode and the positive electrode may further include one or more of a conductive material and an adhesive. In particular, the positive electrode may further contain various additives for supplementing or improving electrochemical characteristics.

[0067] The conductive material may be a material that improves conductivity. Any material that does not cause a chemical change in the battery and has conductivity can be used. For example, the conductive material may be used as conductive fibers such as graphite, carbon black, carbon fiber, or metal fiber; conductive whiskers such as carbon fluoride, aluminum powder, nickel metal powder, potassium titanate zinc oxide; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives or a combination thereof, but not limited thereto.

[0068] The adhesive may be a material that assists in the adhesion between the negative electrode current collector and the negative electrode active material or between the positive electrode current collector and the positive electrode active material. For example, the adhesive may be polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, styrene butadiene rubber (SBR), carboxyl methyl cellulose (CMC), etc., but not limited thereto.

[0069] The solid electrolyte layer may be composed of a solid electrolyte.

[0070] The solid electrolyte may be a solid electrolyte that moves electrons or ions, and it includes lithium ions having ionic conductivity.

[0071] The solid electrolyte may be LGPS (Li 10 GeP2S 12 ), LSPSCl (Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 ), sulfide-based solid electrolyte materials such as argyrodite, perovskite (LLTO), garnet (LLZO), NASICON (sodium superionic conductor), LISICON (lithium superionic conductor) and other oxide-based solid electrolyte materials, or polymer-based electrolyte materials such as PEO, but not limited thereto.

[0072] The solid electrolyte can be mixed with the positive electrode active material to form a layer. For example, by mixing the raw material powders of the solid electrolyte and the positive electrode active material in a mutually mixed or closely attached state, the solid electrolyte layer and the positive electrode active material layer can be formed.

[0073] In the technical field, the raw materials of the negative electrode active material, the solid electrolyte, and the positive electrode active material are all in the form of solid powders. Such solid powders can generally be prepared into a slurry form. A slurry is a suspension in which solids are dispersed in a solvent. If the viscosity of the slurry is too high, it is difficult to coat the material. If the dispersibility of the slurry is poor, the uniformity of the material is low, and the concentration and compressibility of the slurry determine the density of the material.

[0074] The battery cell manufacturing unit 10 can separately make the negative electrode active material, the solid electrolyte, and the positive electrode active material in powder form into a slurry form, and can form the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer by sequential lamination.

[0075] Each of the slurries can use different solvents according to the raw materials used and be prepared under appropriate preparation conditions (temperature, humidity, etc.) to have specified viscosity, dispersibility, concentration, and compressibility. Each of the slurries can be laminated by methods commonly used in the technical field (such as coating, impregnation, or spraying).

[0076] The ion transport speed, lifespan, etc. of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer can be controlled by thickness, density, and uniformity.

[0077] In the battery cell manufacturing unit 10, at least one pore can be formed inside each layer or at the layer - to - layer interface of the negative electrode active material layer, the solid electrolyte layer, or the positive electrode active material layer, or at least one foreign substance can flow in from the outside.

[0078] As an embodiment, the battery cell manufacturing unit 10 can manufacture a mono - cell. The mono - cell can be a single battery cell composed of the negative electrode, the solid electrolyte, and the positive electrode.

[0079] As another embodiment, the battery cell manufacturing unit 10 can manufacture a stack - cell. The stack - cell can be a battery cell formed by laminating multiple mono - cells.

[0080] The laminated battery cell may include a bipolar battery cell well-known in the art. The bipolar battery cell may be composed of a bipolar electrode and an electrolyte. The bipolar electrode is an electrode in which a current collector is placed in the middle and the negative electrode active material layer and the positive electrode active material layer are provided on both sides. The bipolar battery cell is formed by alternately laminating the bipolar electrode and the solid electrolyte layer. Therefore, the bipolar battery cell may have a structure similar to that of a battery cell formed by laminating a plurality of the single battery cells.

[0081] The pressing unit 20 may be configured to uniformly press the battery cell.

[0082] The pressing unit 20 may be arranged after the battery cell manufacturing unit 10 and may receive the battery cell from the battery cell manufacturing unit 10.

[0083] The pressing unit 20 may be provided in a plate shape or a roll shape capable of applying a uniform pressure to a specified area. However, the shape of the pressing unit 20 is not limited thereto.

[0084] The pressing unit 20 may press the battery cell in one direction on the upper side or the lower side, or may press the battery cell in both the upper and lower directions. However, the pressing method of the pressing unit 20 is not limited thereto.

[0085] As the pressing unit 20 uniformly presses the battery cell, at least a part of the pores inside the battery cell can be removed.

[0086] As the pressing unit 20 uniformly presses the battery cell, the interface between the negative electrode active material layer - the solid electrolyte layer or the interface between the solid electrolyte layer - the positive electrode active material layer can be firmly bonded.

[0087] The imaging unit 30 may be provided to radiograph the battery cell and obtain an image (raw image).

[0088] The imaging unit 30 may radiograph the battery cell manufactured in the battery cell manufacturing unit 10 to obtain a first image, and may radiograph the battery cell pressed in the pressing unit 20 to obtain a second image.

[0089] That is, the imaging unit 30 may radiograph the state of the battery cell before being pressed in the pressing unit 20 to obtain a first image, and may radiograph the state of the battery cell after being pressed in the pressing unit 20 to obtain a second image.

[0090] The imaging unit 30 may be provided as a conventional X-ray device or a three-dimensional CT device.

[0091] The three-dimensional CT imaging device is an X-ray tomography device that uses X-rays to generate cross-sectional images of three-dimensional objects. The images obtained from the CT imaging device photograph the three-dimensional object at multiple angles, continuously obtain cross-sectional images composed of pixels, and stack the multiple obtained cross-sectional images to reconstruct a three-dimensional image composed of three-dimensional pixels (voxels). Therefore, the three-dimensional image can be a three-dimensional video image or a two-dimensional cross-sectional image extracted from the object's tomogram.

[0092] The first image and the second image can be two-dimensional images obtained from the X-ray device or multiple tomographic images extracted from the three-dimensional images obtained from the three-dimensional CT device.

[0093] The recovery unit 40 can be set to recover the pressurized battery cell.

[0094] The recovery unit 40 can be arranged after the pressurizing unit 20 and receive the pressurized battery cell from the pressurizing unit 20.

[0095] After the imaging unit 30 photographs the pressurized battery cell and obtains the second image, the recovery unit 40 can recover the battery cell.

[0096] The recovery unit 40 can be set to recover when the performance of the battery cell is suitable and discard when the performance of the battery cell is not suitable.

[0097] The control unit 50 can overall control the operations of the battery cell manufacturing unit 10, the pressurizing unit 20, the imaging unit 30, the recovery unit 40, etc.

[0098] The control unit 50 can process the first image or the second image obtained in the imaging unit 30.

[0099] The control unit 50 can detect first inactive region information by processing the first image and detect second inactive region information by processing the second image.

[0100] The first inactive region information or the second inactive region information can be information including at least one of the brightness values, brightness distributions, number of pixels, pixel sizes, and pixel areas of the pixels in the first image and the second image.

[0101] Using the brightness values or brightness distributions of the respective pixels, the control unit 50 can distinguish the first inactive region and the first active region in the first image and distinguish the second inactive region and the second active region in the second image.

[0102] In addition, using the number of pixels, the control unit 50 can measure the number of pixels occupied by the first inactive region in the first image, and can measure the number of pixels occupied by the second inactive region in the second image.

[0103] In addition, using the pixel size, the control unit 50 can measure the size of the first inactive region in the first image, and can measure the size of the second inactive region in the second image.

[0104] In addition, using the pixel area, the control unit 50 can measure the area of the first inactive region in the first image, and can measure the area of the second inactive region in the second image.

[0105] The control unit 50 can derive the inactivity degree of the battery cell by using the first inactive region information or the second inactive region information.

[0106] The inactivity degree can represent the degree or proportion occupied by the first inactive region in the first image, or can represent the degree or proportion occupied by the second inactive region in the second image.

[0107] The inactivity degree can be used as an approximation of the performance of the battery cell. The inactivity degree can be an index for determining whether the performance of the battery cell is suitable.

[0108] The inactivity degree of the battery cell can be calculated according to the following formula 1.

[0109] [Formula 1]

[0110] Inactivity degree (%) = [Area of the second inactive region (A2) / Total area inside the battery cell (A total )] * 100

[0111] The control unit 50 can determine the suitability of the battery cell performance by comparing the inactivity degree of the battery cell with a preset reference value.

[0112] The reference value can be 0.1% or less. Thus, only when the inactivity degree is 0.1% or less, the battery cell can be determined to be suitable.

[0113] The control unit 50 can include an image processing unit, an operation execution unit, and a determination unit.

[0114] The image processing unit can receive the first image or the second image from the imaging unit 30.

[0115] The image processing unit can detect the first inactive region information by processing the first image, and can detect the second inactive region information by processing the second image.

[0116] The operation execution unit can derive the inactivity degree of the battery cell by using the first inactivity area information or the second inactivity area information.

[0117] The determination unit can determine the suitability of the performance of the battery cell by comparing the inactivity degree with a preset reference value.

[0118] Figure 2 It is a flowchart briefly showing a manufacturing method of a all-solid-state battery according to an embodiment of the present invention. Hereinafter, each step of the flowchart will be described in detail.

[0119] Refer to Figure 1 and Figure 2 , a manufacturing method of a all-solid-state battery according to an embodiment of the present invention may include: Step S10, manufacturing a battery cell including a solid electrolyte through a battery cell manufacturing unit; Step S20, performing radiography on the battery cell through an imaging unit to obtain a first image; Step S30, uniformly pressing the battery cell through a pressing unit; Step S40, performing radiography on the pressed battery cell through the imaging unit to obtain a second image; Step S50, processing the first image through a control unit to detect first inactivity area information, and processing the second image to detect second inactivity area information; and Step S60, deriving the inactivity degree of the battery cell by using the first inactivity area information or the second inactivity area information through the control unit, and determining whether the battery cell is suitable by comparing the inactivity degree of the battery cell with a preset reference value.

[0120] In addition, according to an embodiment, after Step S60 of determining whether the battery cell is suitable, it may further include: Step S70, through the control unit, when it is determined that the battery cell is not suitable for the reference value, using the first inactivity area information or the second inactivity area information to change the manufacturing conditions or the uniform pressing conditions of the battery cell to control the battery cell manufacturing unit or the pressing unit.

[0121] In Step S10 of manufacturing the battery cell, the battery cell is manufactured through a battery cell manufacturing unit 10.

[0122] Specifically, the battery cell is manufactured into a layered structure in which the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer are sequentially laminated between the positive electrode current collectors.

[0123] In Step S10 of manufacturing the battery cell, at least one pore may be formed inside each layer or at the layer interface of the negative electrode active material layer, the solid electrolyte layer, or the positive electrode active material layer, or at least one foreign substance may flow in from the outside.

[0124] When the pores or the foreign matters are present inside the respective layers or at the layer interface, the part having the pores or the foreign matters has a lower density or forms nodules compared with other parts, and thus is electrochemically inactive.

[0125] In step S20 of obtaining the first image, the manufactured battery cell is radiographed by the imaging unit 30.

[0126] The imaging unit 30 can be set as an X-ray device or a three-dimensional CT device. The imaging unit 30 can radiograph the manufactured battery cell to obtain a first image.

[0127] The first image can be a two-dimensional image obtained from the X-ray device.

[0128] The first image can be a plurality of tomographic images extracted from a three-dimensional image obtained from the three-dimensional CT device.

[0129] In step S30 of uniformly pressing the battery cell, the battery cell can be uniformly pressed by the pressing unit 20.

[0130] As the battery cell is pressed, the negative electrode, the solid electrolyte, and the positive electrode can be compressed. Thus, the inside of the battery cell can be densified into a high density.

[0131] In step S40 of obtaining the second image, the pressed battery cell is radiographed by the imaging unit 30.

[0132] The imaging unit 30 can be set as an X-ray device or a three-dimensional CT device. At this time, the imaging unit 30 can be the same as that used in step S20 of obtaining the first image.

[0133] The imaging unit 30 can radiograph the pressed battery cell to obtain a second image.

[0134] The second image can be a two-dimensional image obtained from the X-ray device.

[0135] The second image can be a plurality of tomographic images extracted from a three-dimensional image obtained from the three-dimensional CT device.

[0136] In step S50 of detecting the inactive region information, the control unit 50 detects first inactive region information by processing the first image, and detects second inactive region information by processing the second image.

[0137] The first inactive region information and the second inactive region information can include at least one of the brightness values, brightness distributions, number of pixels, pixel sizes, and pixel areas of the respective pixels of the first image and the second image.

[0138] In step S60 of determining whether the battery cell is suitable, the control unit 50 can derive the inactivity degree of the battery cell by using the first inactive region information or the second inactive region information, and determine whether the battery cell is suitable by comparing the inactivity degree with a preset reference value.

[0139] According to an embodiment, the inactivity degree is calculated according to Equation 1 below.

[0140] [Equation 1]

[0141] Inactivity degree (%) = [Area (A2) of the second inactive region / Total area (A total ) inside the battery cell] * 100

[0142] It can be seen therefrom that the inactivity degree is the percentage (%) of the area of the inactive region relative to the total area inside the battery cell.

[0143] The inactivity degree is an approximate value of the performance of the battery cell, and the performance can be approximately derived according to the area of the battery cell without performing an electrochemical evaluation on the battery cell.

[0144] The reference value of the inactivity degree can be 0.1% or less. Thus, only when the inactivity degree is 0.1% or less, the battery cell can be determined to be suitable and the manufacturing process can be completed.

[0145] When it is determined that the inactivity degree does not meet the reference value, subsequent step S70 of controlling the battery cell manufacturing unit or the pressing unit can be performed.

[0146] In step S70 of controlling the battery cell manufacturing unit or the pressing unit, the control unit 50 changes the manufacturing conditions of the battery cell or the uniform pressing conditions by using the first inactive region information or the second inactive region information.

[0147] The control unit 50 can compare the first inactive region information of the first image and the second inactive region information of the second image, and change the manufacturing conditions of the battery cell or the uniform pressing conditions according to the change rate of the inactivity degree of the battery cell before and after pressing.

[0148] In order to reflect the changed manufacturing conditions of the battery cell or the uniform pressing conditions in the subsequent manufacturing process, the control unit 50 can control the battery cell manufacturing unit 10 or the pressing unit 20.

[0149] That is, analyzing the reason why the performance of the battery cell is not suitable, the control unit 50 changes the manufacturing conditions of the battery cell or the uniform pressing conditions according to the analysis result, and supplements the subsequent process to manufacture a new battery cell.

[0150] Figure 3 This is a conceptual diagram for explaining a method of detecting non-active region information by processing an image through image processing. Refer to Figure 3 , and steps S50 for detecting the non-active region information and the control unit 50 will be described in more detail.

[0151] However, the method of detecting the first non-active region information by processing the first image is the same as the method of detecting the second non-active region information by processing the second image. Hereinafter, the first image and the second image will be collectively referred to as an image, and the first non-active region and the second non-active region will be collectively referred to as a non-active region.

[0152] According to Figure 3 , the control unit 50 can derive a processed image M' by performing image processing on the original image M received from the imaging unit 30.

[0153] The image processing can extract the brightness value or brightness distribution of each pixel from the image M and use it to distinguish the non-active region and the active region within the image M.

[0154] For example, the image M may include a gray region 100, a black region 200, and a white region 300.

[0155] The gray region 100 photographs the active region.

[0156] According to the tomographic image of a certain part of the battery cell shown in the image M, the gray region 100 may be one of the negative active material, the solid electrolyte, or the positive active material, or a mixed part thereof.

[0157] The black region 200 and the white region 300 photograph the non-active region.

[0158] The black region 200 is a part that is darker than the gray region 100 and appears darker, and it photographs the pores inside the battery cell.

[0159] The white region 300 is a part that is brighter than the gray region 100 and appears brighter, and it photographs foreign matters inside the battery cell.

[0160] In step S50 of detecting the non-active region information, the control unit 50 can extract the black region 200 and the white region 300 from the image M and distinguish them from the gray region 100.

[0161] With reference to the enlarged view of part A of the processed image M', the control unit 50 can pixelate the image M and extract the information of each pixel. The control unit 50 can distinguish the pixels in the black region 200 and the white region 300 from the pixels in the gray region 100 and mark them with different colors or boundary lines, etc.

[0162] That is, the region occupied by the pores or the foreign matter is visualized as pixels. The visualized pixels refer to the pixels occupying the non-active region.

[0163] The control unit 50 can distinguish and mark the pixels occupying the non-active region among the total pixels of the image M.

[0164] The control unit 50 can measure the number of pixels occupying the non-active region and can measure the pixel size or pixel area of one pixel.

[0165] According to one embodiment, the step S50 of detecting the non-active region information may further include the following steps:

[0166] Measuring the number of non-active region pixels (N x , x = 1 or 2) and the total number of pixels (N total ) inside the battery cell from the image;

[0167] Calculating the area (A pixel ) of each pixel according to the radiography conditions; and

[0168] Deriving the area (A x , x = 1 or 2) of the non-active region and the total area (A total ) inside the battery cell.

[0169] In the step of measuring the number of non-active region pixels (N x ) and the total number of pixels (N total ) inside the battery cell from the image, the number of pixels visualized in the step S50 of detecting the non-active region can be measured.

[0170] At this time, the total number of pixels (N total ) inside the battery cell refers to the number of pixels occupying the entire region inside the battery cell, and can be the total number of pixels of the entire region including the non-active region and the active region.

[0171] In the step of calculating the area (A pixel ) of each pixel according to the radiography conditions, the area (A pixel ) of each pixel in the image is obtained through the radiography conditions of the battery cell.

[0172] The area (A of each pixelpixel ) It can be calculated by considering the magnification, field of view (FOV), and resolution set when photographing the battery cell with CT.

[0173] When deriving the area (A x ) of the inactive region and the total area (A total ) inside the battery cell, in the step of multiplying the area (A pixel ) of each pixel by the number of pixels (N x ) in the inactive region and the total number of pixels (N total ) inside the battery cell respectively, the area (A x ) of the inactive region and the total area (A total ) inside the battery cell can be derived.

[0174] Figure 4 It is a conceptual diagram for explaining a method of distinguishing a pore-based inactive region and a foreign object-based inactive region from an image and performing image processing.

[0175] According to Figure 4 , when performing image processing on the original image M received from the imaging unit 30, the control unit 50 can separately derive the image M' processed centered on pores P and the image M' processed centered on foreign objects. F .

[0176] In the step S50 of detecting the inactive region information, when comparing the first image and the second image, the increasing and decreasing trends of the inactivity degree in the black region 200 and the white region 300 may show opposite situations.

[0177] When the battery cell is pressurized by the pressurizing unit 20, the pores inside the battery cell decrease or are removed, and at the same time, the number of the black regions 200 decreases, or the size or area decreases, and the gray region 100 can be further densified.

[0178] On the contrary, when the battery cell is pressurized by the pressurizing unit 20, the foreign objects inside the battery cell are compressed, causing its area to increase, and thus the size or area of the white region 300 can increase.

[0179] For example, when the multiple foreign objects are only concentrated and distributed in a part of the battery cell, after the battery cell undergoes the uniform pressurizing step S30, the inactivity degree of the entire battery cell may be suitable for the performance reference value, but the inactivity degree of the inactive region formed by the foreign objects may locally increase. Since the ionic conductivity of the battery cell in the inactive region is very low, resulting in a significant reduction in the ionic transport speed and life of the battery cell, etc., it is difficult to consider that the performance of the battery cell is suitable.

[0180] Therefore, preferably, when pressurized by the pressurizing unit 20, the degree of inactivity can be uniformly reduced in the entire area of the battery cell, and the control unit 50 needs to separately derive from one image M an image M' processed centering on pores P and an image M' processed centering on foreign matters. F .

[0181] The control unit 50 can distinguish the inactive area formed by the pores and the inactive area formed by the foreign matters in the image M and process them separately.

[0182] The control unit 50 can derive the degree of inactivity based on the pores from the image M' processed centering on pores P and can derive the degree of inactivity based on the foreign matters from the image M' processed centering on foreign matters. F

[0183] The control unit 50 can separately derive the rate of change of the degree of inactivity based on the pores and the rate of change of the degree of inactivity based on the foreign matters.

[0184] Figure 5 And Figure 6 is a diagram enlarging a part of the CT tomogram of the battery cell manufactured as an implementation example, which is suitable for analyzing the decreasing trend or increasing trend of the degree of inactivity. Hereinafter, with reference to Figure 5 and Figure 6 , the step S70 of controlling the battery cell manufacturing unit or the pressurizing unit by changing the manufacturing conditions or uniform pressurizing conditions of the battery cell will be described in detail. Figure 5 and Figure 6 The battery cells and imaging conditions of

[0185] In an implementation example, the battery cell is a single battery cell with an area of 12 cm 2 (40 mm in the horizontal direction and 30 mm in the vertical direction) and a thickness of 0.15 mm (±0.03 mm). Before and after pressurizing the battery cell in the pressurizing unit 20, three-dimensional CT imaging was performed using a three-dimensional CT imaging device to obtain a first image and a second image.

[0186] The imaging conditions of the CT imaging device are as follows: the tube voltage (X-ray tube voltage) is 140 kV, the tube current (X-ray tube current) is 100 μA, the magnification is 5.5x, the field of view (FOV) is in the range of 27.5 mm * 27.5 mm, and the image resolution is 21.63 μm.

[0187] Figure 5 is a diagram showing the case where the degree of inactivity decreases when comparing the first image and the second image.

[0188] Figure 5 Part (a) of which is the first image, and part (b) is the second image.

[0189] Compare Figure 5 By comparing part (a) and part (b) of which, it can be confirmed that there are white lines at the same positions, but there is no difference before and after the uniform pressing step S30. It is considered that the white lines are caused by the wrinkling or folding of the battery cell, so it can be judged that they have nothing to do with the uniform pressing step S30.

[0190] Figure 5 B-1 shown in part (a) of which and B-2 shown in part (b) are at the same position on a cross-section of the negative electrode layer of the battery cell. The multiple black areas visible in B-1 are the pores before the battery cell is pressed, and the multiple black areas visible in B-2 are the pores after the battery cell is pressed.

[0191] By comparing the black areas of B-1 and B-2, it can be confirmed that both their quantity and size decrease. This indicates that through the pressure applied to the battery cell, the layers constituting the interior of the battery cell combine, and the multiple pores included in the interior of the battery cell merge or are removed.

[0192] However, when the inactivity derived from part (b) of which exceeds 0.1%, it is necessary to change the manufacturing conditions of the battery cell or the uniform pressing conditions. Figure 5 As an example, when the inactivity of a battery cell uniformly pressed at a pressure of 50 tons (ton) for 10 minutes exceeds 0.1%, the inactive area formed by the pores may be the cause.

[0193] In this case, in the uniform pressing step S30, the control unit 50 can control the pressing unit 20 to apply a pressure of more than 50 tons (ton) to the battery cell or change the pressing time to more than 10 minutes.

[0194] On the other hand, in the step S10 of manufacturing the battery cell, the control unit 50 can also consider changes in the manufacturing conditions of the slurry of the negative electrode active material, the solid electrolyte, or the positive electrode active material or their lamination methods by controlling the battery cell manufacturing unit 10.

[0195]

[0196] Figure 6 is a diagram showing a case where the inactivity increases when comparing the first image and the second image.

[0197] Figure 6 Figure 6 Part (a) of which is the first image, and part (b) is the second image. At this time, Figure 6C-1 shown in part (a) and C-2 shown in part (b) are at the same position on a cross-section of the negative electrode layer of the cell.

[0198] The white area visible in C-1 is a foreign object before the cell is pressurized, and the white area visible in C-2 is a foreign object after the cell is pressurized.

[0199] By comparing the white area of C-1 and the white area of C-2, it can be confirmed that its size has increased. This indicates that through the pressure applied to the cell, the foreign object has spread thinly and its area has increased, indicating that the ionic conductivity in the area with the foreign object can be reduced.

[0200] In this case, in step S10 of manufacturing the cell or step S30 of uniform pressurization, it can be judged that it is important to prevent foreign objects from flowing in.

[0201] Therefore, each raw material constituting the negative electrode active material layer, the positive electrode active material layer, or the solid electrolyte layer is configured to have a higher purity, or the manufacturing conditions or methods when manufacturing the slurry from each raw material can be changed.

[0202] On the other hand, the manufacturing environment in step S10 of manufacturing the cell or step S30 of uniform pressurization can be improved.

[0203] The present invention has been described with reference to an embodiment shown in the accompanying drawings, but this is merely exemplary, and those of ordinary skill in the art can understand that various modifications and equivalent other embodiments can be obtained therefrom. Therefore, the true scope of protection of the present invention is only determined by the appended claims.

[0204] Industrial Applicability

[0205] The present invention relates to a method and device for manufacturing an all-solid-state battery, and can provide an all-solid-state battery manufacturing device that predicts the performance of a cell through non-destructive testing and evaluates the manufacturing process of the cell.

[0206] Related National Research and Development Projects

[0207] - Project Inherent Number: 1415178681

[0208] - Project Number: 20012349

[0209] - Department Name: Ministry of Strategy and Finance, Korea

[0210] - Name of the Project Management (Special) Agency: Korea Institute for Advancement of Technology

[0211] - Name of the Research Project: Development of Lithium-based Next-generation Secondary Battery Performance Improvement and Manufacturing Technology

[0212] - Research Project Name: 50cm 2 Development of Manufacturing Equipment for All-Solid-State Battery Cells of 50cm and Above

[0213] - Contribution Rate: 1 / 1

[0214] - Name of the Organization Implementing the Project: Future Co., Ltd.

[0215] - Research Period: January 1, 2022 to December 31, 2022

Claims

1. A method for manufacturing an all-solid-state battery, characterized in that: It includes: A battery cell manufacturing step, in which a battery cell including a solid electrolyte is manufactured through a battery cell manufacturing unit; A first image acquisition step, in which the battery cell is radiographed through an imaging unit to obtain a first image; A pressurization step, in which the battery cell is uniformly pressurized through a pressurization unit; A second image acquisition step, in which the pressurized battery cell is radiographed through the imaging unit to obtain a second image; An information detection step, in which a control unit processes the first image to detect first non-active area information, and processes the second image to detect second non-active area information; and A determination step, in which the control unit uses the first non-active area information or the second non-active area information to derive the non-activity degree of the battery cell, and determines whether the battery cell is suitable by comparing the non-activity degree of the battery cell with a preset reference value.

2. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that: After the step of determining whether the battery cell is suitable, the following steps are further included: Through the control unit, when it is determined that the battery cell is not suitable for the reference value, the first non-active area information or the second non-active area information is used to change the manufacturing conditions or the uniform pressurization conditions of the battery cell, so as to control the battery cell manufacturing unit or the pressurization unit.

3. The method for manufacturing an all-solid-state battery according to claim 2, characterized in that: In the step of controlling the battery cell manufacturing unit or the pressurization unit, by comparing the first non-active area information of the first image and the second non-active area information of the second image, and according to the change rate of the non-activity degree of the battery cell before and after pressurization, the manufacturing conditions or the uniform pressurization conditions of the battery cell are changed.

4. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that: The first non-active area information and the second non-active area information are information including at least one of the brightness value, brightness distribution, number of pixels, pixel size, and pixel area of each pixel of the first image and the second image.

5. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that: In the step of determining whether the battery cell is suitable, the non-activity degree of the battery cell is derived according to the following formula 1, [Formula 1] Degree of inactivity = [Area A2 of the second inactive region / Total area A inside the battery cell 总 * 100, where the unit of the degree of inactivity is %.

6. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that: The battery cell is a single battery cell or a stacked battery cell.

7. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that: The imaging unit is an X-ray device or a three-dimensional CT device.

8. An all-solid-state battery manufacturing device, characterized in that: It includes: A battery cell manufacturing unit for manufacturing a battery cell containing a solid electrolyte, A pressurization unit for uniformly pressurizing the battery cell, An imaging unit for radiographing the battery cell to obtain a first image or a second image, and The control unit detects first inactive region information by processing the first image, and detects second inactive region information by processing the second image, derives the inactivity degree of the battery cell by using the first inactive region information or the second inactive region information, and determines whether the battery cell is suitable by comparing the inactivity degree of the battery cell with a preset reference value.

9. The all-solid-state battery manufacturing apparatus according to claim 8, wherein when it is determined that the battery cell is not suitable for the reference value, the control unit uses the first inactive region information or the second inactive region information to change the manufacturing conditions or the uniform pressing conditions of the battery cell, so as to control the battery cell manufacturing unit or the pressing unit.

10. The all-solid-state battery manufacturing apparatus according to claim 9, wherein when the control unit controls the battery cell manufacturing unit or the pressing unit, by comparing the first inactive region information of the first image and the second inactive region information of the second image, and according to the change rate of the inactivity degree of the battery cell before and after pressing, the manufacturing conditions or the uniform pressing conditions of the battery cell are changed.

11. The all-solid-state battery manufacturing apparatus according to claim 8, wherein the first inactive region information and the second inactive region information are information including at least one of the brightness value, brightness distribution, number of pixels, pixel size, and pixel area of each pixel of the first image and the second image.

12. The all-solid-state battery manufacturing apparatus according to claim 8, wherein in the step of determining whether the battery cell is suitable, the inactivity degree of the battery cell is derived according to the following formula 1, [Formula 1] Degree of inactivity = [Area A2 of the second inactive region / Total internal area A of the battery cell 总 *100, where the unit of the degree of inactivity is %.

13. The all-solid-state battery manufacturing apparatus according to claim 8, wherein the battery cell is a single battery cell or a stacked battery cell.

14. The all-solid-state battery manufacturing apparatus according to claim 8, wherein the imaging unit is an X-ray device or a three-dimensional CT device.

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