Rechargeable battery manufacturing apparatus and method for calibrating the same

Abstract

According to an exemplary embodiment, an apparatus for manufacturing a secondary battery is provided. The apparatus includes a masking fixture configured to hold electrode leads and busbars and including first to fourth inner walls defining openings for exposing the electrode leads and busbars; 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 towards the electrode leads and busbars; a detector; a processor; and a controller.

Description

Technical Field

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[0003]

[0001] The present invention relates to a secondary battery manufacturing apparatus and a method for calibrating the same. This application claims the benefit of Korean Application No. 10-2023-0135756, filed on Oct. 12, 2023, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as handsets, notebook computers, and wireless vacuum cleaners. In recent years, due to improvements in energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased dramatically, and as the driving range of battery electric vehicles (BEVs) has increased to a level comparable to that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to mobility.

[0003] In order to meet the rapid growth in demand for secondary batteries for mobility, cell manufacturers have been forced to make huge capital expenditures. Each company is increasing productivity per line in order to maximize the return on invested capital, and for this purpose, various studies for improving yield and productivity are continuing.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the technical idea of the present invention is to provide an apparatus for manufacturing a secondary battery and a method for calibrating the same with improved productivity.

Means for Solving the Problems

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, an apparatus for manufacturing a secondary battery is provided. The apparatus includes an oscillator configured to generate a processing beam, a scanner head configured to irradiate a material with the processing beam generated by the oscillator, a drive unit configured to move the scanner head, and a processor configured to locate the focal position of the scanner head, wherein the oscillator includes a built-in sensor configured to sense reflected light, which is the portion of the processing beam reflected by the material, and the processor is configured to locate the focal position of the scanner head based on a signal generated by the built-in sensor.

[0006] The above processor is configured to collect the intensity profile of the reflected light based on the above signal.

[0007] The above processor is configured to find the focal position of the scanner head based on the above intensity profile of the reflected light.

[0008] The processor described above is configured to find the focal position of the scanner head based on the duration of the peak in the intensity profile of the reflected light described above.

[0009] The processor described above is configured to find the focal position of the scanner head based on the shape of the intensity profile of the reflected light described above.

[0010] The processor described above is configured to find the focal position of the scanner head based on the poles of the intensity profile of the reflected light described above.

[0011] According to an exemplary embodiment, a method for calibrating a secondary battery manufacturing apparatus is provided. The method includes the steps of: irradiating a material with a processing beam, the processing beam being irradiated by a scanner head positioned at a first working distance from the material; sensing a first reflected light, which is the portion of the processing beam reflected off the material at the first working distance; and finding the focal position of the scanner head based on the intensity profile of the first reflected light, the first reflected light being sensed by an internal sensor built into an oscillator configured to generate the processing beam.

[0012] The step of finding the focal position of the scanner head described above is based on the duration of the peak in the intensity profile described above.

[0013] The step of finding the focal point of the scanner head described above is based on the shape of the intensity profile described above.

[0014] The focal point position of the scanner head described above is based on the pole of the intensity profile described above.

[0015] The above method further includes the steps of moving the scanner head to a second working distance, irradiating the material with the processing beam at the second working distance, and sensing a second reflected light which is the portion of the processing beam reflected by the material at the second working distance.

[0016] The focal position of the scanner head described above is known based on the intensity profile of the second reflected light described above.

[0017] The processing beam is irradiated onto a first portion of the material at the first working distance, and onto a second portion of the material located away from the first portion at the second working distance. [Effects of the Invention]

[0018] According to an exemplary embodiment of the present invention, the position of the focus of the scanner head can be accurately known. As a result, the productivity and yield of secondary battery manufacturing can be improved.

[0019] The effects obtainable from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those having ordinary knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects associated with implementing the exemplary embodiments of the present disclosure can also be derived by those having ordinary knowledge in the technical field from the exemplary embodiments of the present disclosure.

Brief Description of Drawings

[0020] [Figure 1] It is a drawing showing a secondary battery manufacturing apparatus according to an exemplary embodiment. [Figure 2] The oscillator of FIG. 1 is shown. [Figure 3] It is a flowchart for explaining a method of calibrating a secondary battery manufacturing apparatus according to an exemplary embodiment. <000​​​​​​​​​​​​​​​​​​​​​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 this specification and the claims are not to be construed as limited to ordinary or dictionary meanings, but can be construed as meanings and concepts consistent with the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the terms in order to explain his own invention in the best way.

[0022] Therefore, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical ideas of the present invention. Thus, there can be various equivalents and modifications that can replace these at the time of this application.

[0023] Also, in the description of the present invention, when it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0024] Embodiments of the present invention are provided to more fully explain the present invention to an ordinary technician. Therefore, the shapes and sizes of the components in the drawings can be exaggerated, omitted, or shown schematically for a clearer explanation. Thus, the sizes and ratios of each component do not fully reflect the actual sizes and ratios.

[0025] (First Embodiment) FIG. 1 is a drawing showing a secondary battery manufacturing apparatus 100 according to an exemplary embodiment.

[0026] FIG. 2 shows the oscillator 110 of FIG. 1.

[0027] Referring to FIGS. 1 and 2, the secondary battery manufacturing apparatus 100 can include an oscillator 110, an optical cable 120, a scanner head 130, a driving device 140, and a controller 150.

[0028] The secondary battery manufacturing apparatus 100 can be configured to perform laser welding. As a non-limiting example, welding by the secondary battery manufacturing apparatus 100 may be keyhole welding. During keyhole welding, a high-energy-density processing beam PB can be irradiated onto the workpiece, generating a molten pool and high-temperature molten vapor that attempts to press the molten pool together. The secondary battery manufacturing apparatus 100 can be configured to process (i.e., weld) the frame of a battery module or to weld the electrode leads of a battery cell to a busbar.

[0029] The oscillator 110 may be a laser (Light Amplification by Stimulated Emission of Radiation) device. The oscillator 110 may be configured to generate a processing beam PB. The processing beam PB may be a laser beam. According to an exemplary embodiment, the processing beam PB may be near-infrared. According to an exemplary embodiment, the wavelength of the processing beam PB may be in the range of about 750 nm to about 2500 nm. According to an exemplary embodiment, the wavelength of the processing beam PB may be about 1070 nm.

[0030] As a non-limiting example, oscillator 110 may be a fiber laser. Based on what is described herein, ordinary technicians of the art can easily arrive at embodiments in which oscillator 110 is any one of the following: semiconductor laser devices, Nd:YAG laser devices, and titanium-sapphire (Ti-Sapphire) laser devices; in other examples, oscillator 110 is a liquid laser device, such as a dye laser device; and in other examples, oscillator 110 is a gaseous laser device, such as a helium-neon laser device, a carbon dioxide laser device, or an excimer laser device.

[0031] The oscillator 110 may include multiple pump diodes 111, a pump coupler 112, a first Bragg grating 113, a second Bragg grating 114, a first optical isolator 115, a second optical isolator 116, an active fiber 117, an output port 118, and an internal sensor 119.

[0032] The pump diodes 111 can be configured to generate light based on an external signal and / or power (e.g., an electrical signal and / or power). The number of pump diodes 111 in the oscillator 110 can be determined based on the intensity of the processing beam PB to be output. That is, the more pump diodes 111 there are, the greater the maximum intensity of the processing beam PB can be. The light generated from the pump diodes 111 can be collected into a feeding fiber (or multiple feeding fibers) via a pump coupler 112. The light collected into the feeding fiber can be coupled into an active fiber 117. The first optical isolator 115 and the second optical isolator 116 can be configured to block the propagation of light in the reverse direction.

[0033] The first Bragg grating 113 and the second Bragg grating 114 can each be reflectors. Light introduced into the active fiber 117 can be reflected and amplified by the first Bragg grating 113 and the second Bragg grating 114, thereby generating a processing beam PB. The reflectivity of the second Bragg grating 114 may differ from that of the first Bragg grating 113. The reflectivity of the second Bragg grating 114 may be lower than that of the first Bragg grating 113. As a result, the processing beam PB that has passed through the second Bragg grating 114 can be output through the output port 118. The output port 118 may be connected to an optical cable 120 and may be configured to emit the processing beam PB through free space.

[0034] The built-in sensor 119 can be configured to sense reflected light, which is a portion of the processing beam PB reflected off the material MT. The reflected light can be re-incidentated to the oscillator 110 via the scanner head 130 and sensed by the built-in sensor 119. The built-in sensor 119 can be interposed between the second optical isolator 116 and the output port 118, or it can be tapped into the waveguide (i.e., optical fiber) of the processing beam PB between the second optical isolator 116 and the output port 118. The built-in sensor 119 can be configured to generate a signal (e.g., an electrical signal) based on the reflected light.

[0035] The processing beam PB generated by the oscillator 110 can be coupled to the scanner head 130 via the optical cable 120. Alternatively, the processing beam PB may be transmitted to the scanner head 130 via either a free-space optical system or an optical integrated circuit.

[0036] The scanner head 130 can be configured to irradiate the material MT with the processing beam PB. The scanner head 130 can be configured to focus the processing beam PB. It can also be configured to scan a workpiece with the processing beam PB in order to process the workpiece after the calibration of the secondary battery manufacturing apparatus 100, which includes the scanner head 130, has been completed.

[0037] The scanner head 130 may include various optical elements that allow for the illumination, scanning, and focusing of the processing beam PB, such as beam splitters, Garbo mirrors, F-theta lenses, dichroic mirrors, splitters, half-wave plates, quarter-wave plates, polarizers, and optical filters. The focal point of the scanner head 130 may be the focal point of the processing beam PB illuminated by the scanner head 130. The focal point of the scanner head 130 may be the resulting focal point of the various optical elements included in the scanner head 130. The processing beam PB coupled to the scanner head 130 via the optical cable 120 can be focused to the focal point of the scanner head 130 via the various optical elements of the scanner head 130.

[0038] The drive unit 140 can be configured to move the scanner head 130. The drive unit 140 may include a servo motor and a linear encoder, which can be configured to precisely control and sense the movement of the scanner head 130 (more specifically, the amount of movement in the X direction, Y direction, and Z direction).

[0039] Here, the X and Y directions may be substantially parallel to the surface of the material MT, and the Z direction may be substantially perpendicular to the surface of the material MT. The X, Y, and Z directions may be substantially perpendicular to each other. The X, Y, and Z directions may be defined based on the surface of the stage supporting the material MT.

[0040] The material MT may include metallic substances. The material MT can be partially melted by irradiation with the processing beam PB. The reflected light, which is the portion of the processing beam PB reflected by the material MT, can reach the built-in sensor 119 of the oscillator 110 as described above. The material MT may, but is not limited to, a sample for locating the focal position of the scanner head 130.

[0041] The controller 150 can be configured to control various operations of the oscillator 110, the scanner head 130, and the drive unit 140. The controller 150 can be configured to generate signals to control the oscillation of the oscillator 110, the chopping frequency of the processing beam PB, the intensity of the processing beam PB, and the driving of the scanner head 130 and the drive unit 140.

[0042] The processor 160 can be configured to analyze the signal generated by the built-in sensor 119. More specifically, the processor 160 can be configured to collect an intensity profile of reflected light based on the signal generated by the built-in sensor 119. The processor 160 can be configured to find the focal position of the scanner head 130 based on the intensity profile of reflected light. The processor 160 can be configured to determine the focus of the scanner head 130 based on the change in the intensity profile of reflected light in response to the working distance WD of the scanner head 130.

[0043] For example, the controller 150 may be configured to generate signals for controlling the movement of the scanner head 130 by the drive unit 140. To find the focal position of the scanner head 130, the scanner head 130 may be moved by a working distance WD of the process window, where the process window may be a range that includes the working distance WD when the focus of the scanner head 130 for a known processing beam PB is on the material MT. Here, the focus of the scanner head 130 for a known processing beam PB may be known by either the product specification or optical modeling. Optical modeling may be provided based on the volume, density, molar heat capacity, melting point, phase transformation energy of the metal, and the output of the processing beam PB of the material MT, which is the target metal.

[0044] For example, if the working distance WD is 30 mm, and the focus of the beam PB is known to be on the material MT, and the process window size is approximately ±20 mm, the drive unit 140 can be configured to move the scanner head 130 so that the working distance WD varies in the range of approximately 10 mm to approximately 50 mm. From the working distance WD modified by the drive unit 140, the intensity profile of the reflected light of the processing beam PB can be collected.

[0045] The drive unit 140 can be configured to change the working distance WD of the scanner head 130 at intervals set based on the control signal from the controller 150 (i.e., to move the scanner head 130). The set interval can be in the range of approximately 0.1 mm to approximately 1 mm. In one example, the drive unit 140 can be configured to change the working distance WD of the scanner head 130 at intervals of approximately 0.1 mm. In another example, the drive unit 140 can be configured to change the working distance WD of the scanner head 130 at intervals of approximately 1 mm.

[0046] As a non-limiting example, controller 150 could be a PLC (Programmable Logic Controller). A PLC is a special form of microprocessor-based controller that uses programmable memory to store instructions and controls machines and processes by embodying functions such as logic, sequencing, timing, counting, and arithmetic. PLCs are easy to operate and program. Controller 150 may include a power supply, a CPU (Central Process Unit), input interfaces, output interfaces, communication interfaces, and memory devices.

[0047] Here, the controller 150 and processor 160 can be embodied in hardware, firmware, software, or any combination thereof. For example, the controller 150 and processor 160 may be computing devices such as workstation computers, desktop computers, laptop computers, or tablet computers. The controller 150 and processor 160 may be simple controllers, microprocessors, complex processors such as CPUs and GPUs, processors composed of software, dedicated hardware, or firmware. The controller 150 and processor 160 can be embodied, for example, in general-purpose computers or application-specific hardware such as DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and ASICs (Application Specific Integrated Circuits).

[0048] According to some embodiments, the operation of the controller 150 and processor 160 can be embodied as instructions stored on a machine-readable medium that can be read and executed by one or more processors. Here, the machine-readable medium can include any mechanism for storing and / or transmitting information in a form readable by a machine (e.g., a computing device). For example, the machine-readable medium can include ROM (Read Only Memory), RAM (Random Access Memory), magnetic disk storage medium, optical storage medium, flash memory device, electrical, optical, acoustic or other forms of radio signals (e.g., carrier waves, infrared signals, digital signals, etc.) and any other signals.

[0049] Firmware, software, routines, and instructions can be configured to perform the operations described for controller 150 and processor 160, or any of the processes described below. However, this is for illustrative purposes only, and it should be understood that the operations of controller 150 and processor 160 described above can also be caused by computing devices, processors, controllers, or other devices that execute firmware, software, routines, instructions, etc.

[0050] Due to tolerances in the optical system, including the oscillator 110, cable 120, and scanner head 130, the focal point of the scanner head 130 as confirmed in the product specification may differ from the actual focal point of the scanner head 130. According to an exemplary embodiment, the focal point of the scanner head 130 is determined using an internal sensor 119 inside the oscillator 110, so that the focal point of the scanner head 130 can be determined with high precision. The internal internal sensor 119 is a self-aligning element because it is based on a fiber optics system, which reduces the time required for alignment and realignment of the optical system. Here, alignment of the optical system may be an initial setting for measurement and / or inspection, and realignment may be an additional setting to calibrate alignment deviations due to thermal vibration. Furthermore, the use of the internal sensor 119 can reduce the cost of purchasing additional internal sensors and reduce the resources (e.g., development resources) required to track the movement of the processing beam PB.

[0051] (Second Embodiment) Figure 3 is a flowchart illustrating a method for calibrating a secondary battery manufacturing apparatus according to an exemplary embodiment.

[0052] Figure 4 is a diagram illustrating a method for calibrating a secondary battery manufacturing apparatus according to an exemplary embodiment.

[0053] Figures 5a to 5d are graphs illustrating a method for calibrating a secondary battery manufacturing apparatus according to an exemplary embodiment.

[0054] Referring to Figures 1 and 3, at P110, the processing beam PB can be irradiated onto the material MT. The processing beam PB generated by the oscillator 110 can be irradiated onto the material MT via the scanner head 130. The processing beam PB can transfer energy to the material MT, which can change the state of the surface and the vicinity of the surface of the material MT. For example, the surface and vicinity of the surface of the material MT irradiated with the processing beam PB can be melted.

[0055] At P120, reflected light can be detected. The reflected light may be the portion of the processing beam PB reflected by the material MT. The reflected light may be isotropic light, such as scattered light, but is not limited to this. The reflected light can be transmitted to the oscillator 110 via the scanner head 130 and the optical cable 120. The reflected light can be detected by the built-in sensor 119 of the oscillator 110.

[0056] In P130, the focus of the scanner head 130 can be determined based on the intensity profile of the reflected light. The built-in sensor 119 can generate a signal indicating the intensity of the reflected light based on the reflected light. The processor 160 can be coupled to the built-in sensor 119. The processor 160 can be configured to collect the intensity profile of the reflected light based on the signal generated by the built-in sensor 119.

[0057] Referring to Figures 1, 3, and 4, the collection of P110, P120, and reflected light intensity profiles can be repeated multiple times while varying the working distance WD. This allows for obtaining multiple reflected light intensity profiles corresponding to the working distance WD, as shown in Figures 5a to 5d.

[0058] For example, the scanner head 130 can be configured to irradiate a processing beam PB onto a first portion P1 of the material MT at a position separated from the material MT by a first working distance WD1. The first reflected light, which is the portion of the processing beam PB reflected by the first portion P1 of the material MT, can be sensed by a built-in sensor 119 of the oscillator 110, and a first intensity profile of the first reflected light can be collected by the processor 160.

[0059] The scanner head 130 can be configured to irradiate a processing beam PB onto a second portion P2 of the material MT at a position separated from the material MT by a second working distance WD2. The second reflected light, which is the portion of the processing beam PB reflected by the second portion P2 of the material MT, can be sensed by the built-in sensor 119 of the oscillator 110, and the processor 160 can collect a second intensity profile of the second reflected light.

[0060] The surface modification of the first portion P1 can result in different optical properties from the untreated portion of material M1. This allows the treatment beam PB to be irradiated onto the second portion P2, which is separated horizontally (e.g., in the X and / or Y directions) from the first portion P1, in order to collect an intensity profile from a second working distance D2.

[0061] Multiple reflected light intensity profiles may include peak intensities. At peak intensities, the light sensor 119 may, but is not limited to, saturate. In Figures 5a, 5c, and 5d, the reflected light intensity profiles can maintain and then decrease peak intensities for a set period of time. This is because the surface (or vicinity of the surface) of the material MT is outside the focus (or field of focus) of the scanner head 120 relative to the processing beam PB, resulting in either no change in the state of the surface and vicinity of the material MT, or a long time for such a change to occur.

[0062] As a result, the durations PD1, PD3, and PD4 of the peaks PK1, PK3, and PK4 in the reflected light intensity profiles of Figures 5a, 5c, and 5d may be relatively long. For example, the durations PD1, PD3, and PD4 may be similar to the duration of the processing beam PB that induces the reflected light.

[0063] In contrast, in Figure 5b, the duration of the peak in the reflected light intensity profile may be relatively short. This is because the surface (or vicinity of the surface) of the material MT is at the focal point (or depth of field) of the scanner head 120 relative to the processing beam PB, causing the surface (or vicinity of the surface) of the material MT to melt instantaneously. When the surface of the material MT melts, the reflectivity of the material MT may decrease, which can reduce the intensity of the reflected light.

[0064] Due to the decrease in reflected light intensity, the reflected light intensity profile in Figure 5b may include an additional pole point AP, where the slope of the graph is substantially zero. The reflected light intensity at pole point AP may be lower than the reflected light intensity at the peak. Additional poles in the reflected light intensity profile can be induced by the melting of the material MT within the duration of the processing beam PB.

[0065] As a result, the duration PD2 of the peak PK2 may be relatively short. For example, the duration PD2 of the peak PK2 may be less than or equal to about half the duration of the pulse of the processing beam PB. For example, the duration PD2 of the peak PK2 may be less than or equal to about one-third the duration of the pulse of the processing beam PB. For example, the duration PD2 of the peak PK2 may be less than or equal to about one-quarter the duration of the pulse of the processing beam PB. Here, the duration of the pulse of the processing beam PB can be defined based on the full width at half maximum and / or full width.

[0066] The focal position of the scanner head 130 can be determined based on the intensity profile of the reflected light. The focal position of the scanner head 130 can also be determined based on the shape of the intensity profile of the reflected light. The shape of the above profile may include the duration of the peaks and the number of poles.

[0067] More specifically, one of the intensity profiles of reflected light collected from multiple working distances WD can be selected, and the working distance WD corresponding to the selected intensity profile of reflected light can be determined as the focal position of the scanner head 130.

[0068] For example, the intensity profile of reflected light collected from multiple working distances WD has the shortest peak time, and the working distance WD corresponding to the selected intensity profile of reflected light can be determined as the focal position of the scanner head 130.

[0069] As another example, the intensity profile of reflected light collected from multiple working distances WD with the most poles can be selected, and the working distance WD corresponding to the selected intensity profile of reflected light can be determined as the focal position of the scanner head 130. Here, a pole is the point where the slope of the graph is zero, and if melting occurs within the duration of the reflected light pulse, the intensity profile of the reflected light can have multiple (e.g., two) poles.

[0070] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be a variety of equivalents and modifications that can be substituted for them at the time of filing.

Claims

1. An oscillator configured to generate a processing beam, A scanner head configured to irradiate a material with the processing beam generated by the oscillator, A drive device configured to move the scanner head, A processor configured to locate the focal position of the scanner head, Includes, The oscillator includes a built-in sensor configured to sense reflected light, which is a portion of the processing beam reflected by the material, and A secondary battery manufacturing apparatus, wherein the processor is configured to find the position of the focal point of the scanner head based on the signal generated by the built-in sensor.

2. The secondary battery manufacturing apparatus according to claim 1, wherein the processor is configured to collect an intensity profile of the reflected light based on the signal.

3. The secondary battery manufacturing apparatus according to claim 2, wherein the processor is configured to find the position of the focal point of the scanner head based on the intensity profile of the reflected light.

4. The secondary battery manufacturing apparatus according to claim 3, wherein the processor is configured to find the position of the focal point of the scanner head based on the duration of the peak of the intensity profile of the reflected light.

5. The secondary battery manufacturing apparatus according to claim 3, wherein the processor is configured to find the position of the focal point of the scanner head based on the shape of the intensity profile of the reflected light.

6. The secondary battery manufacturing apparatus according to claim 3, wherein the processor is configured to find the position of the focal point of the scanner head based on the pole of the intensity profile of the reflected light.

7. A step of irradiating a material with a processing beam, wherein the processing beam is irradiated by a scanner head that is separated from the material by a first working distance, A step of sensing the first reflected light, which is the portion of the processing beam reflected by the material at the first working distance, The steps include finding the focal position of the scanner head based on the intensity profile of the first reflected light, Includes, A method for calibrating a secondary battery manufacturing apparatus, wherein the first reflected light is detected by a built-in sensor incorporated in an oscillator configured to generate the processing beam.

8. A method for calibrating a secondary battery manufacturing apparatus according to claim 7, wherein the step of finding the focal position of the scanner head is based on the duration of the peak of the intensity profile.

9. A method for calibrating a secondary battery manufacturing apparatus according to claim 7, wherein the step of finding the focal position of the scanner head is based on the shape of the intensity profile.

10. A method for calibrating a secondary battery manufacturing apparatus according to claim 7, wherein the position of the focal point of the scanner head is based on the pole of the intensity profile.

11. The steps include moving the scanner head to a second working distance, The steps include irradiating the material with the processing beam at the second working distance, A step of sensing a second reflected light, which is the portion of the processing beam reflected by the material at the second working distance, A method for calibrating a secondary battery manufacturing apparatus according to claim 7, further comprising:

12. A method for calibrating a secondary battery manufacturing apparatus according to claim 11, wherein the position of the focal point of the scanner head is known based on the intensity profile of the second reflected light.

13. A method for calibrating a secondary battery manufacturing apparatus according to claim 11 or 12, wherein the processing beam is irradiated onto a first portion of the material at a first working distance and onto a second portion of the material located away from the first portion of the material at a second working distance.

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