Apparatus for manufacturing secondary battery and method for manufacturing secondary battery using the same

Abstract

According to an exemplary embodiment, an apparatus for manufacturing a secondary battery is provided, the apparatus including: a masking jig configured to fix an electrode lead and a bus bar and including first to fourth inner walls defining an opening for exposing the electrode lead and the bus bar, a first beam source configured to generate a welding beam, a second beam source configured to generate an inspection beam, a scanner head configured to direct the welding beam and the inspection beam toward the electrode lead and the bus bar, a detector, a processor, and a controller.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for manufacturing a secondary battery and a method for manufacturing a secondary battery using the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0084675, filed July 8, 2022, and Korean Patent Application No. 10-2023-0084584, filed June 30, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of wireless devices, such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0004] To meet the rapid growth in demand for secondary batteries for mobility, cell manufacturers are facing huge capital expenditures. Each company is increasing productivity per line to maximize return on invested capital, and to that end, various research efforts are ongoing to improve yield and productivity. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the technical idea of ​​the present invention is to provide an apparatus for manufacturing a secondary battery with improved productivity and a method for manufacturing a secondary battery using the same. [Means for solving the problem]

[0006] According to an exemplary embodiment of the present invention to solve the above-described problems, there is provided an apparatus for manufacturing a secondary battery, the apparatus including: a masking jig configured to fix an electrode lead and a bus bar and including first to fourth inner walls defining openings exposing the electrode lead and the bus bar; a first beam source configured to generate a welding beam; a second beam source configured to generate an inspection beam; a scanner head configured to direct the welding beam and the inspection beam toward the electrode lead and the bus bar; a servo motor configured to move the scanner head; a detector configured to sense a reflected beam that is a portion of the inspection beam reflected from the electrode lead and the bus bar; a processor configured to collect aperture data including a first coordinate of the first inner wall and a second coordinate of a second inner wall based on the inspection signal generated by the detector; and a controller configured to control the servo motor based on the aperture data of the electrode lead and the bus bar.

[0007] The processor is configured to calculate coordinates of a centerline of the aperture based on the aperture data.

[0008] The coordinate of the centerline of the opening is an average of a first coordinate of the first inner wall and a second coordinate of the second inner wall.

[0009] The controller is configured to modify welding positions of the electrode lead and the bus bar based on the coordinates of the centerline.

[0010] The welding position is a portion of the electrode lead and the bus bar that is intended to be welded by the welding beam.

[0011] The length of the opening is greater than the width of the electrode lead.

[0012] The scanner head is configured to scan the electrode leads and the bus bars with the welding beam along a plurality of spiral lines.

[0013] The center of each of the plurality of spiral lines is on the centerline of the opening in the masking jig.

[0014] According to an exemplary embodiment, there is provided a method for manufacturing a secondary battery, the method including: scanning a bus bar and an electrode lead with an inspection beam through an opening in a masking jig, correcting coordinates of welding positions of the bus bar and the electrode lead to calculate corrected welding positions, and welding the bus bar and the electrode lead based on the corrected welding positions, wherein the masking jig is configured to apply pressure to the electrode lead and the bus bar.

[0015] The masking fixture includes a first inner wall and a second inner wall that define the opening.

[0016] The length of each of the first and second inner walls is greater than the width of the electrode lead.

[0017] Scanning the bus bars and the electrode leads with the inspection beam includes collecting aperture data representative of the apertures in the masking fixture.

[0018] The aperture data includes a first coordinate of the first inner wall and a second coordinate of the second inner wall.

[0019] The welding position is corrected based on centerline data including coordinates of the centerline of the masking jig.

[0020] The centerline data is collected based on the aperture data.

[0021] The coordinate of the centerline is an average of the first coordinate of the first inner wall and the second coordinate of the second inner wall.

[0022] The modified weld location is on the centerline.

[0023] The method further includes determining a defect in the electrode lead based on a three-dimensional image of the bus bar and the electrode lead.

[0024] A three-dimensional image of the busbars and the electrode leads is captured by scanning the busbars and the electrode leads with an inspection beam.

[0025] The opening includes a first portion exposing a surface of the bus bar and a second portion exposing a surface of the electrode lead, and the defect in the electrode lead is determined based on a difference between a depth measured at the first portion and a depth measured at the second portion.

[0026] According to an exemplary embodiment, a method for manufacturing a secondary battery is provided, the method including: scanning a bus bar and an electrode lead with an inspection beam through an opening in a masking jig, the masking jig including a first inner wall and a second inner wall that define the opening; and monitoring contamination of the masking jig based on profiles of the first inner wall and the second inner wall.

[0027] The contamination of the masking jig is monitored based on the roughness of the profile of the first inner wall and the second inner wall.

[0028] The contamination of the masking fixture is monitored based on the distance between the first inner wall and the second inner wall. [Effects of the Invention]

[0029] A method for manufacturing a secondary battery according to an exemplary embodiment of the present invention can collect aperture data and centerline data of a component using optical coherence tomography (OCT), and weld bus bars and electrode leads based on the aperture data and centerline data. OCT determines the three-dimensional shape of the component without errors due to surface roughness. Furthermore, coupling the OCT optical system to the scanner head of the welding beam optical system can minimize the scanner head movement time required for autofocusing and center inspection, thereby improving the productivity of secondary batteries.

[0030] The effects obtained by the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from implementing the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a diagram illustrating an apparatus for manufacturing a secondary battery according to an exemplary embodiment; [Figure 2] FIG. [Figure 3] FIG. [Figure 4] 1 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment. [Figure 5] 1 is a graph illustrating a method for manufacturing a secondary battery according to an exemplary embodiment. [Figure 6] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 7] 1 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe his own invention.

[0033] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can replace them at the time of this application.

[0034] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0035] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or illustrated schematically for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0036] (First embodiment) FIG. 1 is a diagram showing a secondary battery manufacturing apparatus 100 according to an exemplary embodiment.

[0037] FIG. 2 is a perspective view showing the masking jig 170. As shown in FIG.

[0038] FIG. 3 is a plan view showing the masking jig 170. As shown in FIG.

[0039] Referring to Figures 1 to 3, according to an exemplary embodiment, the secondary battery manufacturing apparatus 100 may include a first beam source 110, a scanner head 120, an OCT optical system 130, a processor 140, a controller 150, a servo motor 160, and a masking jig 170.

[0040] The secondary battery manufacturing apparatus 100 may be configured to process the electrode leads EL and the bus bars BB. The secondary battery manufacturing apparatus 100 may be configured to perform laser welding. The secondary battery manufacturing apparatus 100 may be configured to weld the electrode leads EL and the bus bars BB.

[0041] The first beam source 110 may be a laser (Light Amplification by Stimulated Emission of Radiation) device. The first beam source 110 may be configured to generate a welding beam WB. The welding beam WB may be a laser beam. According to an exemplary embodiment, the welding beam WB may be near-infrared. According to an exemplary embodiment, the wavelength of the welding beam WB may be in the range of approximately 750 nm to approximately 2500 nm. According to an exemplary embodiment, the wavelength of the welding beam WB may be approximately 1070 nm.

[0042] For example, the first beam source 110 may be a solid-state laser such as a semiconductor laser, a neodymium-yttrium-argon (Nd:YAG) laser, a titanium-sapphire (Ti-Sapphire) laser, or an optical fiber laser. For another example, the first beam source 110 may be a liquid laser such as a dye laser. For another example, the first beam source 110 may be a gas laser such as a helium-neon laser, a carbon dioxide laser, or an excimer laser.

[0043] The welding beam WB generated by the first beam source 110 may be coupled to the scanner head 120. According to an exemplary embodiment, the welding beam WB may be transmitted to the scanner head 120 via any one of free space optics, optical integrated circuits, and fiber optics.

[0044] The OCT optical system 130 may include a second beam source 131 , a beam splitter 133 , a reference mirror 135 , a detector 137 , a first scanning mirror 138 , and a second scanning mirror 139 .

[0045] The OCT optical system 130 may be configured to capture a three-dimensional image of the electrode lead EL and the bus bar BB. The OCT optical system 130 may be based on a Michelson interferometer. The operation of the OCT optical system may be based on a phase delay between a reference beam RFB and a reflected beam RB. The phase delay indicates a difference in time of flight between the reflected beam RB and the reference beam RFB, and the difference in time of flight may contain information about the three-dimensional image of the electrode lead EL and the bus bar BB. The reflected beam RB may be a portion of the inspection beam IB reflected by the sample (i.e., the electrode lead EL and the bus bar BB). By scanning the surfaces of the electrode lead EL and the bus bar BB with the inspection beam IB, a depth profile (i.e., the depth along the X- and Y-direction coordinates of the electrode lead EL and the bus bar BB) of the scanned portion of the electrode lead EL and the bus bar BB may be obtained, thereby capturing a three-dimensional image of the electrode lead EL and the bus bar BB. Here, the depth is the Z-direction coordinate of the uppermost surface of the assembly of the electrode lead EL and the bus bar BB.

[0046] Here, the X direction and the Y direction are directions substantially parallel to the surface of the bus bar BB, and the Z direction is a direction substantially perpendicular to the surface of the bus bar BB. The X direction, the Y direction, and the Z direction may be substantially perpendicular to each other.

[0047] The X direction, Y direction, and Z direction may be defined based on the opening 170H of the masking jig 170. For example, the Z direction may be the depth direction of the opening 170H of the masking jig 170, the X direction may be the extension direction of the first inner wall 170S1 and the second inner wall 170S2 that define the opening 170H, and the Y direction may be the extension direction of the third inner wall 170S3 and the fourth inner wall 170S4 that define the opening 170H.

[0048] The second beam source 131 may be a laser device. The second beam source 131 may be configured to generate the inspection beam IB. The inspection beam IB may be a laser beam. According to an exemplary embodiment, the inspection beam IB may be near-infrared. According to an exemplary embodiment, the wavelength of the inspection beam IB may be in the range of approximately 750 nm to approximately 2500 nm. According to an exemplary embodiment, the wavelength of the inspection beam IB may be different from the wavelength of the welding beam WB. According to an exemplary embodiment, the wavelength of the inspection beam IB may be even shorter than the wavelength of the welding beam WB. According to an exemplary embodiment, the wavelength of the inspection beam IB may be approximately 820 nm.

[0049] According to an exemplary embodiment, the inspection beam IB may be collimated. According to an exemplary embodiment, the inspection beam IB may be parallel light. That is, the inspection beam IB may be non-converging light and non-diverging light. According to an exemplary embodiment, the second beam source 131 may include a collimation lens, or a collimation lens may be interposed between the second beam source 131 and the beam splitter 133.

[0050] The beam splitter 133 may be on the optical path of the inspection beam IB between the scanner head 120 and the second beam source 131. The inspection beam IB may be transmitted to the beam splitter 133. The beam splitter 133 may be configured to split the inspection beam IB. As a non-limiting example, the beam splitter 133 may be configured to transmit a portion of the inspection beam IB and reflect a portion of the inspection beam IB to generate the reference beam RFB. The reflectivity of the beam splitter 133 may be substantially the same as the transmittance of the beam splitter 133, but is not limited thereto. The reflectivity of the beam splitter 133 may be higher than the transmittance of the beam splitter 133, or the reflectivity of the beam splitter 133 may be lower than the transmittance of the beam splitter 133.

[0051] Reference beam RFB may be reflected by reference mirror 135 and transmitted through beam splitter 133 to detector 137. Inspection beam IB transmitted through beam splitter 133 may be coupled into scanner head 120 via first scanning mirror 138 and second scanning mirror 139 in sequence.

[0052] The first scanning mirror 138 may be in the optical path of the inspection beam IB between the beam splitter 133 and the scanner head 120. The second scanning mirror 139 may be in the optical path of the inspection beam IB between the first scanning mirror 138 and the scanner head 120. Each of the first scanning mirror 138 and the second scanning mirror 139 may be a galvo mirror. Each of the first scanning mirror 138 and the second scanning mirror 139 may include a reflective surface and a servo motor configured to drive (e.g., rotate) the reflective surface. By driving the first scanning mirror 138 and the second scanning mirror 139, the electrode lead EL and the bus bar BB can be scanned with the inspection beam IB.

[0053] Scanner head 120 may include a dichroic mirror 121, a first scanning mirror 123, a second scanning mirror 124, and lenses 125 and 127. Scanner head 120 may be configured to direct the welding beam WB and the inspection beam IB toward the electrode leads EL and the bus bars BB, so that the electrode leads EL and the bus bars BB can be inspected by the inspection beam IB and welded by the welding beam WB. Scanner head 120 may scan the electrode leads EL and the bus bars BB with the welding beam WB and the inspection beam IB.

[0054] The inspection beam IB and the welding beam WB coupled to the scanner head 120 may be transmitted to a dichroic mirror 121. The dichroic mirror 121 may be in an optical path between the first beam source 110 and the electrode lead EL and bus bar BB. The dichroic mirror 121 may be in an optical path between the second scanning mirror 139 and the electrode lead EL and bus bar BB. The inspection beam IB reflected by the dichroic mirror 121 and the welding beam WB transmitted through the dichroic mirror 121 may have similar (or substantially the same) optical paths. The optical axes of the inspection beam IB reflected by the dichroic mirror 121 and the welding beam WB transmitted through the dichroic mirror 121 may at least partially overlap. This may achieve autofocusing of the welding beam WB with the inspection beam IB. The dichroic mirror 121 may include, by way of non-limiting example, a distributed Bragg reflector.

[0055] The dichroic mirror 121 may have a high transmittance for the welding beam WB. For example, the transmittance of the dichroic mirror 121 for the wavelength band of the welding beam WB may be 90% or more. For example, the transmittance of the dichroic mirror 121 for the wavelength band of the welding beam WB may be 95% or more. For example, the transmittance of the dichroic mirror 121 for the wavelength band of the welding beam WB may be 99% or more.

[0056] The dichroic mirror 121 may have a high reflectivity for the inspection beam IB. For example, the reflectivity of the dichroic mirror 121 for the wavelength band of the inspection beam IB may be 90% or more. For example, the reflectivity of the dichroic mirror 121 for the wavelength band of the inspection beam IB may be 95% or more. For example, the reflectivity of the dichroic mirror 121 for the wavelength band of the inspection beam IB may be 99% or more.

[0057] The inspection beam IB reflected by the dichroic mirror 121 and the welding beam WB transmitted through the dichroic mirror 121 may be irradiated onto the electrode lead EL and the bus bar BB after sequentially passing through a first scanning mirror 123, a second scanning mirror 124, and lenses 125 and 127. However, without being limited thereto, the dichroic mirror 121 may also be configured to reflect the welding beam WB and transmit the inspection beam IB. In this case, the dichroic mirror may have high reflectivity for the wavelength band of the welding beam and high transmittance for the wavelength band of the inspection beam.

[0058] The first scanning mirror 123 may be in the optical path of the inspection beam IB and the welding beam WB between the dichroic mirror 121 and the electrode lead EL and the bus bar BB. The second scanning mirror 124 may be in the optical path of the inspection beam IB and the welding beam WB between the first scanning mirror 123 and the electrode lead EL and the bus bar BB. Each of the first scanning mirror 123 and the second scanning mirror 124 may be a galvo mirror. Each of the first scanning mirror 123 and the second scanning mirror 124 may include a reflective surface and a servo motor configured to drive (e.g., rotate) the reflective surface. By driving the first scanning mirror 123 and the second scanning mirror 124, the electrode lead EL and the bus bar BB can be scanned with the inspection beam IB and the welding beam WB.

[0059] According to an exemplary embodiment, the first scanning mirror 123 and the second scanning mirror 124 may be configured to scan the electrode leads EL and bus bars BB with the inspection beam IB in addition to the welding beam WB, thereby allowing the first scanning mirror 138 and the second scanning mirror 139 to be omitted or replaced with non-galvo mirrors (i.e., non-driven fixed mirrors).

[0060] Each of lenses 125, 127 may be a scanning lens. For example, one of lenses 125, 127 may be an F-Theta scanning lens, but is not limited thereto. One of lenses 125, 127 may be a flat field scanning lens or a telecentric F-Theta scanning lens.

[0061] F-theta lenses are the standard lens for galvo-scanner-based laser tooling systems. Diffraction-limited, multi-element, and air-spaced lens designs are optimized for a flat field at the image plane and low f-theta distortion. The output beam displacement of an f-theta lens is equal to f*θ, where θ is the angle of incidence of the input beam and f is the focal length. Therefore, the angular velocities of the input and output beams are directly proportional, which allows for constant angular velocity operation of the scanning mirror and simplifies the control system.

[0062] 1, for convenience of illustration, the inspection beam IB and the welding beam WB are shown simultaneously, but the inspection beam IB and the welding beam WB may be irradiated separately onto the electrode lead EL and the bus bar BB. For example, after the electrode lead EL and the bus bar BB are inspected by the inspection beam IB, the elements of the electrode lead EL and the bus bar BB may be welded together by the welding beam WB.

[0063] The area of ​​the welding beam WB on the electrode lead EL and the bus bar BB may be different from the area of ​​the inspection beam IB on the electrode lead EL and the bus bar BB. The area of ​​the welding beam WB on the electrode lead EL and the bus bar BB may be even larger than the area of ​​the inspection beam IB on the electrode lead EL and the bus bar BB. Because the welding beam WB covers a wide area of ​​the electrode lead EL and the bus bar BB, the throughput of the apparatus 100 for manufacturing a secondary battery can be increased. Because the inspection beam IB covers a narrow area of ​​the electrode lead EL and the bus bar BB (i.e., has a narrow FOV (Field of View)), the resolution of three-dimensional modeling of the electrode lead EL and the bus bar BB by the OCT optical system 130 can be improved.

[0064] The electrode lead EL may be an output terminal of each of the battery cells in the cell stack. The cell stack may include a plurality of battery cells and a plurality of separators. The battery cells may include a case electrode assembly, an electrolyte, and an electrode lead EL. The case may be one of a pouch case, a cylindrical case, and a prismatic case. The electrode assembly may be one of a jelly roll type and a stack type. A jelly roll type electrode assembly may include a wound structure of a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly may include a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed therebetween, stacked in sequence. The electrode lead EL may be connected to one of the positive electrode tab and the negative electrode tab.

[0065] The plurality of battery cells connected in parallel may constitute a plurality of banks. The plurality of banks may be connected in series. The number of battery cells connected in parallel in each of the plurality of banks may be determined according to the magnitude of current to be output through the cell stack. The number of banks connected in series may be determined according to the magnitude of voltage to be output through the cell stack.

[0066] The separators may prevent swelling of the battery cells by supporting the battery cells horizontally. According to an exemplary embodiment, the separators may be thermal barriers.

[0067] The busbar assembly BA may include a busbar frame BF and a busbar BB. The busbar BB may be an external connection terminal for outputting the voltage and current of the cell stack and may be coupled to the positive electrode lead EL of the cell stack. The busbar frame BF may support the busbar BB and the electrode lead EL of the cell stack. The busbar assembly BA may further include an integrated circuit such as a cell management controller (CMC) mounted on the busbar frame BF.

[0068] The bus bar BB and the electrode lead EL can be pressed by the masking jig 170. Because the bus bar BB and the electrode lead EL are pressed by the masking jig 170 and the bus bar frame BF, contact between the bus bar BB and the electrode lead EL can be maintained before welding the bus bar BB and the electrode lead EL.

[0069] The masking jig 170 may include openings 170H that expose the bus bars BB and the electrode leads EL. The planar shape of the openings 170H may be substantially rectangular. The planar shape of the openings 170H may include rounded corners, but is not limited to this.

[0070] The masking jig 170 may include first to fourth inner walls 170S1, 170S2, 170S3, and 170S4 that define the opening 170H. The first to fourth inner walls 170S1, 170S2, 170S3, and 170S4 may surround the opening 170H. The first to second inner walls 170S1 and 170S2 may be substantially parallel to the X direction. The third inner wall 170S3 and fourth inner wall 170S4 may be substantially parallel to the Y direction.

[0071] The length of the opening 170H in the X direction may be different from the length of the opening 170H in the Y direction. The length of the opening 170H in the X direction may be longer than the length of the opening 170H in the Y direction. Thus, the X direction may be referred to as the length direction of the opening 170H, and the Y direction may be referred to as the width direction of the opening 170H.

[0072] The length of the opening 170H in the X direction may be different from the width (i.e., the length in the X direction) of the electrode lead EL. The length of the opening 170H in the X direction may be even greater than the width (i.e., the length in the X direction) of the electrode lead EL. This allows the hollow 170H to simultaneously expose the electrode lead EL and the bus bar BB, which allows OCT-based inspection of the electrode lead EL and the bus bar BB.

[0073] The respective lengths of the first inner wall 170S1 and the second inner wall 170S2 may be different from the respective lengths of the third inner wall 170S3 and the fourth inner wall 170S4. The respective lengths of the first inner wall 170S1 and the second inner wall 170S2 may be even greater than the respective lengths of the third inner wall 170S3 and the fourth inner wall 170S4. The respective lengths of the first inner wall 170S1 and the second inner wall 170S2 may be different from the width (i.e., the length in the X direction) of the electrode lead EL. The respective lengths of the first inner wall 170S1 and the second inner wall 170S2 may be even greater than the width (i.e., the length in the X direction) of the electrode lead EL.

[0074] More specifically, the opening 170H may include first to third portions P1, P2, and P3 arranged along the X direction. The first portion P1 of the opening 170H may expose the surface of the bus bar BB. The second portion P2 of the opening 170H may expose the surface of the electrode lead EL. The third portion P3 of the opening 170H may expose the surface of the bus bar BB. However, this is not limited thereto, and the arrangement of the electrode lead EL and the bus bar BB may be reversed. In this case, the first portion P1 and the third portion P3 of the opening 170H may expose the electrode lead EL, and the second portion P2 of the opening 170H may expose the surface of the bus bar BB.

[0075] The first portion P1 of the opening 170H may overlap the bus bar BB (e.g., in the Z direction). The second portion P2 of the opening 170H may overlap the bus bar BB and the electrode lead EL (e.g., in the Z direction). The third portion P3 of the opening 170H may overlap the bus bar BB (e.g., in the Z direction). As a result, the depth measured through the first portion P1 of the opening 170H may differ from the depth measured through the second portion P2 of the opening 170H. That is, the depth measured through the first portion P1 of the opening 170H may be greater than the depth measured through the second portion P2 of the opening 170H. Also, the depth measured through the third portion P3 of the opening 170H may differ from the depth measured through the second portion P2 of the opening 170H. That is, the depth measured through the third portion P3 of the opening 170H may be greater than the depth measured through the second portion P2 of the opening 170H.

[0076] As instructed by the scanning path SP, the scanner head 120 may be configured to scan with the inspection beam IB the portions of the busbar BB and the electrode lead EL exposed by the opening 170H of the masking jig 170. When the portions of the busbar BB and the electrode lead EL are scanned, the first inner wall 170S1 and the second inner wall 170S2 of the masking jig 170 may both be scanned, thereby making it possible to determine the positions of the first inner wall 170S1 and the second inner wall 170S2.

[0077] 3, the first and second coordinates of the first inner wall 170S1 and the second inner wall 170S2 are illustrated as being determined by a single scan, but this is for illustrative purposes only and does not limit the technical concept of the present invention in any way. The first coordinate of the first inner wall 170S1 may be determined by a first scan, and the second coordinate of the second inner wall 170S2 may be determined by a second scan.

[0078] The reflected beam RB may reach the detector 137 via lenses 125, 127, first scanning mirror 123 and second scanning mirror 124, dichroic mirror 121, first scanning mirror 138 and second scanning mirror 139, and beam splitter 133 in sequence.

[0079] Detector 137 may be configured to generate an inspection signal IS based on reflected beam RB and reference beam RFB. Detector 137 may include, for example, a charge coupled device (CCD) camera, a complementary metal oxide semiconductor (CMOS) image sensor, etc. Detector 137 may be configured to transmit inspection signal IS to processor 140.

[0080] The processor 140 may be configured to determine three-dimensional shapes of the electrode lead EL, the bus bar BB, and the masking jig 170 based on the inspection signal IS. The processor 140 may be configured to collect opening data OD. The processor 140 may be configured to collect the opening data OD based on the three-dimensional shapes of the electrode lead EL, the bus bar BB, and the masking jig 170. The opening data OD may include a first coordinate of the first inner wall 170S1 and a second coordinate of the second inner wall 170S2. When the portion of the bus bar BB and the portion of the electrode lead EL are inspected through the opening 170H of the masking jig 170, the first coordinate of the first inner wall 170S1 and the second coordinate of the second inner wall 170S2 may be determined.

[0081] The processor 140 may be configured to collect centerline data CLD representing a centerline 170CL of the opening 170H based on the opening data OD. The centerline data CLD may include coordinates of the centerline 170CL. The processor 140 may be configured to calculate the coordinates of the centerline 170CL of the opening 170 based on the opening data OD. The coordinates of the centerline 170CL of the opening 170 may be an average of a first coordinate of the first inner wall 170S1 and a second coordinate of the second inner wall 170S2. The processor 140 may be configured to transmit the opening data OD and the centerline data CLD to the controller 150.

[0082] The controller 150 may be configured to control the overall operation of the first beam source 110, the scanner head 120, and the servo motor 160. The controller 150 may be configured to generate signals to control the oscillation of the first beam source 110, the chopping frequency of the welding beam WB, the intensity of the welding beam WB, the driving of the first scanning mirror 123 and the second scanning mirror 124, and the driving of the servo motor 160.

[0083] The controller 150 may be configured to generate a signal for controlling the servo motor 160 and the scanner head 120 to weld the electrode lead EL and the bus bar BB based on any one of the opening data OD and the center line data CLD. The controller 150 may be configured to control the movement of the scanner head 120 by the servo motor 160 and the driving of the first scanning mirror 123 and the second scanning mirror 124.

[0084] By way of non-limiting example, controller 150 may be a programmable logic controller (PLC). A PLC is a specialized form of microprocessor-based controller that uses programmable memory to store instructions and implement functions such as logic, sequencing, timing, counting, and arithmetic to control machines and processes. PLCs are easy to operate and program. Controller 150 may include a power supply, a central processing unit (CPU), input interfaces, output interfaces, communication interfaces, and memory devices.

[0085] Here, the processor 140 and the controller 150 may be embodied in hardware, firmware, software, or any combination thereof. For example, the processor 140 and the controller 150 may be a computing device such as a workstation computer, a desktop computer, a laptop computer, or a tablet computer. The processor 140 and the controller 150 may be a simple controller, a complex processor such as a microprocessor, a CPU, or a GPU, a processor configured by software, or dedicated hardware or firmware. The processor 140 and the controller 150 may be embodied in, for example, 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).

[0086] In some embodiments, the operations of processor 140 and controller 150 may be embodied as instructions stored on a machine-readable medium, which may 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 read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, electrical, optical, acoustical, or other forms of radio signals (e.g., carrier waves, infrared signals, digital signals, etc.), and any other signals.

[0087] Firmware, software, routines, and instructions may be configured to perform the operations described or any of the steps described below for processor 140 and controller 150. However, this is for convenience of explanation, and it should be understood that the operations of processor 140 and controller 150 described above may result from a computing device, processor, controller, or other device executing firmware, software, routines, instructions, and the like.

[0088] The servo motor 160 may be configured to translate the scanner head 120. The servo motor 160 may be configured to move the scanner head 120 in a vertical direction (i.e., in the working distance direction). The vertical movement of the scanner head 120 may focus the welding beam WB on the electrode lead EL and the bus bar BB. That is, the scanner head 120 may move vertically so that the focus of the welding beam WB is on the electrode lead EL and the bus bar BB. The servo motor 160 may be configured to move the scanner head 120 in a horizontal direction. The horizontal movement of the scanner head 120 may scan the electrode lead EL and the bus bar BB with the welding beam WB, thereby welding the electrode lead EL and the bus bar BB.

[0089] (Second embodiment) FIG. 4 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0090] 5 is a graph illustrating a method for manufacturing a secondary battery according to an illustrative embodiment. In FIG. 5, the values ​​on the horizontal and vertical axes represent the coordinates of the sampling point SAP1 on the first side wall 170S1, the sampling point SAP2 on the second side wall 170S2, and the point CP on the center line 170CL, and have arbitrary units.

[0091] FIG. 6 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0092] 1 and 3 to 5, at P110, the busbar BB and the electrode lead EL may be scanned by the inspection beam IB. Aperture data OD may be collected through scanning of the busbar BB and the electrode lead EL. To collect the aperture data OD, the inspection beam IB may move along a scanning path SP. The scanning paths SP1 and SP2 may include zigzag lines (e.g., triangular waveform lines). The sampling frequency of the scanning of the inspection beam IB may be in the range of tens of kHz to hundreds of kHz.

[0093] The Z-field measurement range (i.e., depth measurement limit) of the inspection beam IB can be in the range of several mm to tens of mm. The Z-field measurement range (i.e., depth measurement limit) of the inspection beam IB can be in the range of about 3 mm to about 12 mm. The resolution of the inspection beam IB in the Z-axis direction can be in the range of about 1 μm to about 100 μm.

[0094] The diameter of the XY field measurement area (i.e., horizontal scanning range) of the inspection beam IB may be in the range of several mm to several tens of mm. The diameter of the XY field measurement area (i.e., horizontal scanning range) of the inspection beam IB may be in the range of several mm to several tens of mm. The XY plane resolution of the inspection beam IB may be in the range of about 1 μm to about 100 μm. Here, the XY plane may be the scanning plane of the inspection beam IB, and the Z axis may be substantially perpendicular to the XY plane.

[0095] An inspection signal IS may be generated by scanning the busbar BB and the electrode lead EL with the inspection beam IB. The processor 140 may determine a three-dimensional shape of the busbar BB and the electrode lead EL based on the inspection signal IS. The processor 140 may be configured to collect aperture data OD based on the three-dimensional shape of the busbar BB and the electrode lead EL. The processor 140 may be configured to collect centerline data CLD based on the aperture data OD.

[0096] The opening data OD may include a first coordinate of the first inner wall 170S1 and a second coordinate of the second inner wall 170S2. The first inner wall 170S1 and the second inner wall 170S2 may have a depth smaller than that of the bus bar BB and the electrode lead EL. The first coordinate of the first inner wall 170S1 and the second coordinate of the second inner wall 170S2 may be determined by defining the first inner wall 170S1 and the second inner wall 170S2 as boundaries having a depth less than a critical value (or a height equal to or greater than the critical value) in scanning the bus bar BB and the electrode lead EL. FIG. 5 shows a sampling point SAP1 on the first inner wall 170S1, a sampling point SAP2 on the second inner wall 170S2, and a point CP on the center line 170CL calculated from the sampling points SAP1 and SAP2.

[0097] The first coordinate of the first inner wall 170S1, the second coordinate of the second inner wall 170S2, and the coordinate of the center line 170CL may each be on the scanning plane, and thus may each include an X-direction coordinate and a Y-direction coordinate.

[0098] Subsequently, in P120, the quality of the electrode lead EL may be determined. If the electrode lead EL is defective (No), welding of the electrode lead EL and the bus bar BB may not be performed, and the electrode lead EL and the bus bar BB may be classified as defective. The electrode lead EL and the bus bar BB classified as defective may be inspected and reassembled by an operator and / or an inspection system after the welding sequence is completed.

[0099] The defect of the electrode lead EL may be any one of a lead non-insertion defect, a lead excitation defect, a lead cutting defect, and a lead bending defect. The defect of the electrode lead EL may be determined based on the three-dimensional shapes of the electrode lead EL and the bus bar BB exposed by the opening 170H.

[0100] The no-lead insertion occurs when the electrode leads EL are not completely inserted between the bus bar BB and the masking jig 170. For example, in a design in which three electrode leads EL are welded to the bus bar BB, if only two electrode leads EL are inserted between the bus bar BB and the masking jig 170, a partial open defect of the battery cell may be induced. If the depth difference between the first portion P1 and the third portion P3 where the bus bar BB is exposed and the second portion P2 where the electrode leads EL are exposed is less than a critical lower limit, the cell stack may be determined to have a no-lead insertion defect.

[0101] For example, if the thickness of each of the three electrode leads EL is approximately 10 μm, the total thickness of the three electrode leads EL is approximately 30 μm, and the tolerance is approximately 3 μm, the critical lower limit may be approximately 27 μm. Thus, if the difference in depth between the first portion P1 and the third portion P3 and the second portion P2 where the electrode lead EL is exposed is less than approximately 27 μm, the cell stack may be determined to include a no-lead insertion defect.

[0102] Lead excitation and lead bending defects occur when the bus bar BB and the electrode lead EL are not completely adhered to each other despite the application of pressure by the masking jig 170. Generally, the electrode lead EL includes a bent portion due to welding to the bus bar BB, and lead excitation may be induced by the restoring force of the electrode lead EL. If the depth difference between the first portion P1 and the third portion P3 where the bus bar BB is exposed and the second portion P2 where the electrode lead EL is exposed exceeds a critical upper limit, the cell stack may be determined to have one of a lead excitation defect and a lead bending defect.

[0103] For example, if the thickness of each of the three electrode leads EL is about 10 μm, the total thickness of the three electrode leads EL is about 30 μm, and the tolerance is about 3 μm, the critical upper limit may be about 33 μm. Thus, if the depth difference between the first portion P1 and the third portion P3 and the second portion P2 where the electrode lead EL is exposed is about 33 μm or more, it may be determined that the cell stack has either a lead excitation defect or a lead bending defect.

[0104] If the height profile of the second portion P2 changes discontinuously, it can be determined that there is a lead cutting defect.

[0105] Defects in the electrode leads EL, such as lead non-insertion, lead excitation, defective lead cutting, and lead bending, can be determined by the processor 140. The processor 140 can be configured to transmit data on the electrode leads EL defects to the controller 150. This may prevent welding of the defective electrode leads EL and bus bars BB, and the defective electrode leads EL can be repaired by reassembling the electrode leads EL and bus bars BB, thereby increasing the yield and productivity of secondary battery manufacturing.

[0106] 1, 4, and 6, if the electrode lead EL is normal (YES) in P120, the coordinates of the welding position WP may be corrected in P130. According to an exemplary embodiment, each welding pattern WPT may include a spiral line, and the welding position WP may be the center of the welding pattern WPT. The welding position WP may be determined based on a standard model of the busbar BB and electrode lead EL initially fixed by the masking jig 170 (i.e., before inspection of the busbar BB and electrode lead EL). The welding position WP may be the portion of the electrode lead EL and the busbar BB that is scheduled to be welded by the welding beam WB. The initial welding position WP may be the portion of the busbar BB and electrode lead EL that is scheduled to be welded in an ideal case where there are no tolerances for the busbar BB, the electrode lead EL, or the assembly process errors of the electrode lead EL and the busbar BB, or the pressure position tolerance of the masking jig 170.

[0107] A modified welding position CWP may be determined by modifying the welding position WP. The welding position WP may be modified by the controller 150. That is, the modified welding position CWP may be calculated by the controller 150. Each of the modified welding positions CWP may be on the center line 170CL of the opening 170H. The modified welding pattern CWPT may have substantially the same shape as the welding pattern WPT. The modified welding pattern CWPT may be provided by translating the welding pattern WPT. The center of the modified welding pattern CWPT may be the modified welding position CWP.

[0108] Subsequently, in P140, the electrode lead EL and the bus bar BB may be welded based on the modified welding position CWP. Welding the electrode lead EL and the bus bar BB may include scanning the electrode lead EL and the bus bar BB with the welding beam WB along a spiral line to form the modified welding pattern CWPT. If interference occurs between the welding beam WB and the masking jig 170 due to tolerances, defects due to unwelded or weak welds between the electrode lead EL and the bus bar BB may occur. According to an exemplary embodiment, welding the electrode lead EL and the bus bar BB based on the modified welding position CWP may prevent unwelded or weak welds between the electrode lead EL and the bus bar BB, thereby improving the reliability of secondary battery manufacturing.

[0109] (Third embodiment) 1, 4, and 6, in P130, the electrode lead EL and the bus bar BB can also be welded based on the center line data CLD. In this example, the electrode lead EL and the bus bar BB can be directly scanned with the welding beam WB based on the center line data CLD without correcting the weld line based on the center line data CLD. The controller 150 is configured to perform many calculations in addition to correcting the welding position WP. By having the controller 150 generate a signal for welding using the center line data CLD as is, the computing power of the controller 150 can be reduced, thereby improving the continuity and reliability of the process.

[0110] (Fourth embodiment) FIG. 7 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0111] 7, in P210, the busbars BB and electrode leads EL can be scanned with an inspection beam IB. P210 is substantially the same as P110 in FIG. 4, so a duplicated description thereof will be omitted.

[0112] 1, 5, and 7, in P220, the contamination level of the masking jig 170 can be monitored. The contamination level of the masking jig 170 can be monitored based on the profile of the opening 170H of the masking jig 170. When welding the electrode lead EL and the bus bar BB, the masking jig 170 can be contaminated by sputtering of metal materials. If the masking jig 170 is excessively contaminated, incomplete contact between the bus bar BB and the electrode lead EL can cause weak or no welding between the bus bar BB and the electrode lead EL, or the masking jig 170 can damage the bus bar BB and the electrode lead EL.

[0113] When the masking jig 170 is contaminated, the profile of the first inner wall 170S1 and the second inner wall 170S2 of the masking jig 170 (or the profile of the opening 170H of the masking jig 170) may be changed.

[0114] According to an exemplary embodiment, monitoring of the masking jig 170 may be based on the roughness of the profiles of the first inner wall 170S1 and the second inner wall 170S2 of the masking jig 170. If the roughness of the profiles of the first inner wall 170S1 and the second inner wall 170S2 exceeds a critical value, the processor 140 and / or the controller 150 may be configured to generate an alarm for cleaning of the masking jig 170.

[0115] According to another exemplary embodiment, monitoring of the masking jig 170 can be based on the distance (e.g., average distance) between the first inner wall 170S1 and the second inner wall 170S2. If the distance (e.g., average distance) between the first inner wall 170S1 and the second inner wall 170S2 is less than a critical value, the processor 140 and / or the controller 150 can be configured to generate an alarm for cleaning the masking jig 170.

[0116] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0117] 100 Secondary battery manufacturing equipment 110 First Beam Source 120 scanner head 121 Dichroic Mirror 123 First scanning mirror 124 Second scanning mirror 125, 127 lenses 130 OCT optical system 131 Second Beam Source 133 Beam Splitter 135 Reference Mirror 137 Detector 138 First scanning mirror 139 Second scanning mirror 140 processors 150 Controller 160 Servo Motor 170 Masking jig 170CL center line 170H opening, hollow 170S1~S4 Inner wall BA Busbar Assembly BB Busbar BF Busbar Frame CLD centerline data CP points CWP welding position CWPT welding pattern EL electrode lead IB Inspection Beam IS test signal OD Opening Data P1 Part 1 P2 2nd part P3 3rd part RB reflected beam RFB reference beam SAP1 sampling point SAP2 sampling point SP scanning path WB Welding Beam WP welding position WPT welding pattern

Claims

1. a masking jig configured to fix an electrode lead and a bus bar, the masking jig including first to fourth inner walls defining openings through which the electrode lead and the bus bar are exposed; a first beam source configured to generate a welding beam; a second beam source configured to generate an inspection beam; a scanner head configured to direct the welding beam and the inspection beam toward the electrode leads and bus bars; a servo motor configured to move the scanner head; a detector configured to sense a reflected beam that is a portion of the inspection beam reflected from the electrode leads and the bus bars; a processor configured to collect aperture data based on the inspection signal generated by the detector, the aperture data including a first coordinate of the first inner wall and a second coordinate of the second inner wall; a controller configured to control the servo motor based on opening data of the electrode leads and the bus bars.

2. The secondary battery manufacturing apparatus according to claim 1 , wherein the processor is configured to calculate coordinates of a center line of the opening based on the opening data.

3. The secondary battery manufacturing apparatus according to claim 2 , wherein the coordinates of the center line of the opening are an average of a first coordinate of the first inner side wall and a second coordinate of the second inner side wall.

4. the controller is configured to modify welding positions of the electrode lead and the bus bar based on the coordinates of the centerline; The secondary battery manufacturing apparatus according to claim 2 , wherein the welding position is a portion of the electrode lead and the bus bar that is to be welded by the welding beam.

5. A secondary battery manufacturing apparatus as described in claim 1, wherein the length of the opening along the extension direction of the first inner wall and the second inner wall is even greater than the width of the electrode lead.

6. The secondary battery manufacturing apparatus according to claim 1 , wherein the scanner head is configured to scan the electrode leads and the bus bars with the welding beam along a plurality of spiral lines.

7. The secondary battery manufacturing apparatus according to claim 6 , wherein the center of each of the plurality of spiral lines is on the center line of the opening of the masking jig.

8. A method for manufacturing a secondary battery using the secondary battery manufacturing apparatus according to any one of claims 1 to 7, comprising: scanning the bus bars and electrode leads with an inspection beam through openings in a masking fixture; modifying the coordinates of the bus bar and the electrode lead welding positions to calculate modified welding positions; welding the bus bar and the electrode lead based on the corrected welding position; The method for manufacturing a secondary battery, wherein the masking jig is configured to apply pressure to the electrode leads and the bus bars.

9. the masking jig includes a first inner wall and a second inner wall that define the opening; The method of manufacturing a secondary battery according to claim 8 , wherein the length of each of the first inner wall and the second inner wall is greater than the width of the electrode lead.

10. the step of scanning the bus bars and the electrode leads with the inspection beam includes collecting aperture data representative of the apertures in the masking fixture; The method for manufacturing a secondary battery according to claim 8 , wherein the opening data includes a first coordinate of a first inner side wall and a second coordinate of a second inner side wall.

11. The method for manufacturing a secondary battery according to claim 10 , wherein the welding position is corrected based on centerline data including coordinates of a centerline of the masking jig.

12. The method for manufacturing a secondary battery according to claim 11 , wherein the centerline data is collected based on the aperture data.

13. The method of manufacturing a secondary battery according to claim 11 , wherein the coordinate of the center line is an average of the first coordinate of the first inner wall and the second coordinate of the second inner wall.

14. The method for manufacturing a secondary battery according to claim 11 , wherein the modified welding position is on the centerline.

15. determining a defect in the electrode lead based on a three-dimensional image of the bus bar and the electrode lead; 9. The method for manufacturing a secondary battery according to claim 8, wherein the three-dimensional image of the bus bar and the electrode lead is captured by scanning the bus bar and the electrode lead with an inspection beam.

16. the opening includes a first portion exposing a surface of the bus bar and a second portion exposing a surface of the electrode lead; The method of manufacturing a secondary battery according to claim 15 , wherein the defect in the electrode lead is determined based on a difference between a depth measured at the first portion and a depth measured at the second portion.

17. A method for manufacturing a secondary battery using the secondary battery manufacturing apparatus according to claim 1, comprising: scanning the bus bars and the electrode leads with an inspection beam through an opening in a masking jig, the masking jig including a first inner wall and a second inner wall defining the opening; A method for manufacturing a secondary battery, comprising: monitoring contamination of the masking jig based on profiles of the first inner wall and the second inner wall.

18. The method for manufacturing a secondary battery according to claim 17 , wherein the contamination of the masking jig is monitored based on the roughness of the profiles of the first inner side wall and the second inner side wall.

19. The method for manufacturing a secondary battery according to claim 17 , wherein the contamination of the masking jig is monitored based on a distance between the first inner side wall and the second inner side wall.

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