Stack inspection apparatus for electrode plates or cells

Abstract

The present disclosure provides a stack inspection apparatus including a camera unit generating an alignment image by photographing four corner points of an outer circumference of an electrode plate or a unit cell at an upper portion in a stacking direction of the electrode plate or the unit cell, and a light irradiation unit irradiating light to the four corner points of an inspection object, wherein the camera unit includes a sensor recognizing the light irradiated from the light irradiation unit and determining whether the alignment of the electrode plate or the unit cell is defective.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0074998, filed on June 9, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to a stacking inspection device for electrode plates or cell units. Background Technology

[0004] With the rapid increase in the use of fossil fuels, the demand for alternative or clean energy sources is constantly increasing. Among the most active research areas is the generation and storage of electricity using electrochemistry.

[0005] Currently, secondary batteries are a representative example of electrochemical devices that utilize this type of electrochemical energy, and their application is gradually expanding.

[0006] In recent years, with the increasing development of mobile devices such as portable computers, mobile phones, and cameras, the demand for secondary batteries, which serve as the energy source for these devices, has also increased dramatically. Among such secondary batteries, lithium-ion batteries, which exhibit high charge / discharge characteristics and long lifespan and are environmentally friendly, have been extensively studied and are now commercialized and widely used.

[0007] Furthermore, with increasing attention to environmental issues, research is growing on electric vehicles and hybrid electric vehicles that can replace fossil fuel-powered vehicles such as gasoline and diesel cars, which are major contributors to air pollution. While nickel-metal hydride batteries are primarily used as power sources for electric and hybrid electric vehicles, research is actively underway on lithium-ion batteries with high energy density and high discharge voltage, some of which are already in the commercialization stage.

[0008] This lithium secondary battery is manufactured by stacking positive and negative electrodes to form an electrode assembly, and then housing the electrode assembly together with the electrolyte in a secondary battery casing.

[0009] At this point, the stacking process of the positive and negative electrodes is performed in various ways. Stacking can be performed by simply inserting a separator between the positive and negative electrodes; or by manufacturing single cells, dual cells, or full cells, folding or stacking them, and then laminating them. A single cell contains a positive electrode and a separator or contains a negative electrode and a separator; a dual cell contains a positive electrode, a negative electrode, and a separator, and electrodes of the same polarity are arranged on the outermost sides; a full cell contains a positive electrode, a negative electrode, and a separator, and electrodes of different polarities are arranged on the outermost sides.

[0010] In this case, this stacking process is one of the processes that may affect the performance of secondary batteries in the future, in which the positive and negative electrodes must be aligned and stacked symmetrically without twisting up, down, left, or right.

[0011] First, even under any circumstances, when the positive and negative electrodes are stacked, twisting may occur between them, so the positive and negative electrodes themselves need to be stacked and aligned. In addition, stack alignment is also required during the folding of cell units such as single cells, dual cells, and full cells, which include electrodes and separators, and during the stacking of these cell units in the stacking process.

[0012] In particular, the folding process of the cell unit, which involves winding the cell unit placed on the separator, is excellent in terms of processing speed. However, problems such as the spacing between each electrode and twisting in all directions often occur. This becomes a major factor affecting future lifespan and safety testing, since the spacing between the positive and negative electrodes is reversible.

[0013] To address these issues, attempts have been made to improve ACOH by performing stacking and compression of cell units. However, as the number of stacked cells increases, the alignment of cells inside and outside the electrode assembly becomes limited. Consequently, when production conditions are adjusted, a significant number of cells are represented as losses, leading to reduced yield.

[0014] Therefore, there is an urgent need to develop a technology that can solve the above problems and eliminate stacking alignment defects caused by twisting of electrodes and cells in all directions, thereby improving quality and yield. Summary of the Invention

[0015] Technical issues

[0016] This disclosure aims to address the aforementioned issues and other unresolved technical problems.

[0017] Specifically, one object of this disclosure is to provide a stacking inspection apparatus that can improve product quality and yield by identifying stacking alignment defects in real time without changing the main equipment in existing processes.

[0018] Another objective of this disclosure is to provide a stacking inspection apparatus capable of measuring the vertical thickness difference of electrodes or cell units based on the tab forming direction, minimizing the error generated when the operator manually measures the thickness difference, thereby further improving product quality.

[0019] Technical solution

[0020] To achieve the above objectives, according to one embodiment of this disclosure, a stacking inspection apparatus for electrode plates is provided when a first electrode plate and a second electrode plate are stacked such that a diaphragm is inserted between the first electrode plate and the second electrode plate, the stacking inspection apparatus comprising:

[0021] A camera unit generates an aligned image by capturing images of the four corner points of the outer periphery of the first or second electrode plate at the upper part of the stacking direction of the first and second electrode plates; and

[0022] The light irradiation unit, when the first electrode plate and the second electrode plate are stacked, irradiates light from the upper part of the first electrode plate or the second electrode plate onto the four corner points of the first electrode plate and the second electrode plate that are to be inspected.

[0023] The camera unit includes a sensor that identifies light irradiated from the light irradiation unit and determines whether there is a defect in the alignment of the first electrode plate and the second electrode plate.

[0024] In this configuration, the light irradiation unit can irradiate light such that the light passes through even if the first electrode plate or the second electrode plate is partially offset from its stacked position in any direction (left, right, up, down).

[0025] The sensor can identify light irradiated from the light irradiation unit, and can determine an alignment defect when it detects that the light passes through at least one of the four corner points.

[0026] In addition, the sensor can measure the round-trip time of light irradiated from the light irradiation unit.

[0027] Additionally, the stacking inspection device may further include a measurement unit that measures the position-based thickness of each of the first electrode plate and the second electrode plate based on the reciprocating time of each light measured from the sensor.

[0028] Additionally, the stacking inspection device may further include a control unit that, when the sensor determines an alignment defect, corrects the alignment value based on information received from the sensor and instructs the correction of the stacking position of the first electrode plate or the second electrode plate. The control unit determines a defect when the difference in the reciprocating time of each light measured from the sensor is equal to or greater than a specific value, or when the position-based thickness deviation of each of the first and second electrode plates measured from the measuring unit is equal to or greater than a specific value.

[0029] According to another embodiment of this disclosure, a stacking inspection apparatus for cell batteries is provided when stacking cell batteries such that a separator or membrane is inserted between one or more cell batteries, the stacking inspection apparatus comprising:

[0030] A camera unit generates an aligned image by photographing the four corner points of the outer periphery of the cell at the upper part of the cell's stacking direction; and

[0031] A light irradiation unit, when the cell cells are stacked, irradiates light from the top of the cell cells onto the four corners of the cell cell being inspected.

[0032] The camera unit includes a sensor that identifies light irradiated from the light irradiation unit and determines whether the alignment of the unit's battery is defective.

[0033] In other words, it can check not only the alignment of the electrode plates, but also the alignment of the cell units.

[0034] In this configuration, the light irradiation unit can irradiate light such that the light passes through even if the cell is partially offset in any of the left, right, up, or down directions where the cell should be stacked; the sensor can identify the light irradiated from the light irradiation unit and determine an alignment defect when it is detected that the light passes through at least one of the four corner points.

[0035] Furthermore, the sensor can measure the round-trip time of light irradiated from the light irradiation unit, and the stacking inspection device may further include a measurement unit that measures the location-based thickness of each cell based on the round-trip time of each light irradiated from the sensor.

[0036] Additionally, the stacking inspection device may further include a control unit that, when the sensor determines an alignment defect, corrects the alignment value based on information received from the sensor and instructs the correction of the stacking position of the battery cells. The control unit determines a defect when the difference in the round-trip time of each light measured from the sensor is equal to or greater than a specific value, or when the deviation in the position-based thickness of each cell measured from the measuring unit is equal to or greater than a specific value.

[0037] The cell cells using this stacking inspection device can be stacked in a manner where the separator is rolled around the cell cells in one direction, or the cell cells can be stacked in a manner where the separator is folded in a Z-shape, or the cell cells can be stacked in a manner where the separator is inserted between the cell cells and laminated. Attached Figure Description

[0038] Figure 1 This is a perspective view schematically showing a stacking inspection apparatus according to one embodiment of the present disclosure;

[0039] Figure 2 schematically shown Figure 1 Side view of the stacked inspection equipment;

[0040] Figure 3 A side view of a stacking inspection apparatus according to another embodiment of the present disclosure is shown schematically;

[0041] Figure 4 A side view of a stacking inspection apparatus according to another embodiment of the present disclosure is shown schematically. Detailed Implementation

[0042] In order to better understand this disclosure, it will be described in more detail below.

[0043] The terms or words used in this specification and claims should not be construed as being limited to common or dictionary terms, but rather as having meanings and concepts consistent with the technical ideas of this disclosure, based on the inventors' ability to appropriately define the concepts of the terms in order to best describe their own disclosure.

[0044] The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of this disclosure. Singular forms include plural forms as well, unless the context clearly indicates otherwise.

[0045] As used herein, the terms “comprising” or “including” specify the presence of a particular feature, whole, step, action, component, or combination thereof, but do not exclude the presence or addition of different particular features, wholes, steps, components, and / or combinations thereof.

[0046] According to one embodiment of the present disclosure, a stacking inspection apparatus for electrode plates is provided when a first electrode plate and a second electrode plate are stacked such that a diaphragm is inserted between the first electrode plate and the second electrode plate. The stacking inspection apparatus includes:

[0047] The camera unit generates an aligned image by photographing the four corner points of the outer periphery of the first or second electrode plate at the upper part of the stacking direction of the first and second electrode plates; and

[0048] The light irradiation unit, when the first electrode plate and the second electrode plate are stacked, irradiates light from the upper part of the first electrode plate or the second electrode plate onto the four corner points of the first electrode plate and the second electrode plate, which are the objects to be inspected.

[0049] The camera unit includes a sensor that identifies the light irradiated from the light irradiation unit and determines whether there is a defect in the alignment of the first electrode plate and the second electrode plate.

[0050] Now, refer to Figure 1 and Figure 2 This disclosure is described in detail.

[0051] Figure 1 This is a perspective view schematically showing a stacking inspection apparatus 100 according to an embodiment of the present disclosure. Figure 2 schematically shown Figure 1 Side view of the stacked inspection device 100.

[0052] Refer to together Figure 1 and Figure 2 According to one embodiment of the present disclosure, the stacking inspection device 100 is a stacking inspection device 100 that inspects the alignment state of electrode plates 110 and 120 when a first electrode plate 110 and a second electrode plate 120 are stacked such that a diaphragm 130 is inserted between the first electrode plate 110 and the second electrode plate 120.

[0053] The stacking inspection device 100 includes: camera units 141, 142, 143, and 144, which generate alignment images by capturing images of four corner points a, b, c, and d on the outer periphery of the first electrode plate 110 or the second electrode plate 120 at the upper part of the stacking direction of the first electrode plate 110 and the second electrode plate 120; and light illumination units 151, 152, 153, and 154, which illuminate the first electrode plate 110 and the second electrode plate 120 when they are stacked. 153 and 154 irradiate light onto the four corner points of the first electrode plate 110 and the second electrode plate 120, which are the objects of inspection, from the upper part of the first electrode plate 110 or the second electrode plate 120. The camera units 141, 142, 143 and 144 include sensors 161, 162, 163 and 164. The sensors 161, 162, 163 and 164 identify the light irradiated from the light irradiation units 151, 152, 153 and 154 and determine whether there is a defect in the alignment of the first electrode plate 110 and the second electrode plate 120.

[0054] At this time, the light irradiation units 151, 152, 153 and 154 irradiate light, so that the light passes through even if the first electrode plate 110 or the second electrode plate 120 is partially deviated from the position where the first electrode plate 110 or the second electrode plate 120 should be stacked in any direction in the left, right, up and down directions.

[0055] exist Figure 1 and Figure 2In this configuration, light is irradiated without deviation from the corners of electrode plates 110 and 120. Therefore, when electrode plates 110 and 120 are stacked correctly, the light is covered by the outermost electrode plate. However, if they are stacked such that even a portion of the top, bottom, left, or right sides are misaligned, light passes through without being covered by the outermost electrode plate, and the light appears on the lower electrode plate. In this case, sensors 161, 162, 163, and 164 identify the light irradiated from light irradiation units 151, 152, 153, and 154, and determine an alignment defect when light is detected passing through at least one of the four corner points a, b, c, and d.

[0056] At this point, sensors 161, 162, 163, and 164 can visually or audibly notify the operator of this.

[0057] The stacking inspection apparatus 100 of this disclosure may further include a control unit 180, which, when sensors 161, 162, 163, and 164 determine that there is an alignment defect, corrects the alignment value based on the information received from sensors 161, 162, 163, and 164 and instructs to correct the stacking position of the first electrode plate 110 or the second electrode plate 120.

[0058] In other words, since alignment correction can be performed automatically via the control unit 180, alignment correction can be executed in real time.

[0059] Therefore, according to this disclosure, since the alignment of electrode plates 110 and 120 can be determined in real time each time they are stacked, products with better alignment than before can be produced. Furthermore, since the time required for positive-negative electrode spacing checks previously performed during product manufacturing can be reduced, product quality and yield can be improved.

[0060] Meanwhile, sensors 161, 162, 163 and 164 can further measure the round-trip time of light irradiated from light irradiation units 151, 152, 153 and 154.

[0061] In other words, sensors 161, 162, 163, and 164 can measure the time from when light is irradiated by light irradiation units 151, 152, 153, and 154 to when the light is recognized again. That is, the time (S1+S2, S3+S4) from when the light travels from light irradiation units 151, 152, 153, and 154 to the electrode plate 110 and is then recognized by sensors 161, 162, 163, and 164. Figure 2 As shown in the image.

[0062] In this case, there may be a time difference between the four corner points a, b, c, and d when the light is detected again, which can be used to estimate the thickness of the electrode plate at each location.

[0063] Alternatively, the stacking inspection device 100 may further include a measurement unit 170, which measures the position-based thickness of each of the first electrode plate 110 and the second electrode plate 120 based on the reciprocating time (S1+S2, S3+S4) of each light measured from sensors 161, 162, 163 and 164.

[0064] Specifically, the measuring unit 170 stores information about the distance between the light irradiation units 151, 152, 153, and 154 used for each stack and the outermost electrode plate located in each stack, and calculates the interval after stacking new electrode plates based on the reciprocating motion time of the light, so that the thickness of the newly stacked electrode plates can be measured based on [the distance between the outermost electrode plate and the light irradiation units 151, 152, 153, and 154 before stacking - the distance between the outermost electrode plate and the light irradiation units 151, 152, 153, and 154 after stacking new electrode plates].

[0065] Additionally, the control unit 180 may determine a defect when the difference (|S1+S2-(S3+S4)|) between the reciprocating times of each light measured from sensors 161, 162, 163, and 164 is equal to or greater than a specific value, or when the position-based thickness deviation of each of the first electrode plate 110 and the second electrode plate 120 measured from the measurement unit 170 is equal to or greater than a specific value.

[0066] Therefore, as described above, when measuring the thickness at each location of the electrode plate, not only can alignment defects be measured in real time, but also the loading deviation within an electrode plate due to the characteristics of the actual coating process can be measured in real time. Furthermore, electrode plates with large loading deviations based on location can be identified as defective and removed in real time, thereby improving product quality. Additionally, conventionally, there is a problem of errors arising between workers when measuring the thickness of the electrode plates. However, by automating and mechanizing this process, products determined to be of a uniform standard can be obtained, thus improving reliability.

[0067] According to another embodiment of this disclosure, a stacking inspection apparatus for cell cells is provided when stacking cell cells such that a separator or membrane is inserted between one or more cell cells, the stacking inspection apparatus comprising:

[0068] The camera unit generates aligned images by photographing the four corner points of the outer periphery of the cell at the top of the cell stacking direction; and

[0069] The light irradiation unit, when stacking cell units, irradiates light from the top of the cell unit onto the four corners of the cell unit being inspected.

[0070] The camera unit includes a sensor that identifies the light emanating from the light irradiation unit and determines whether there are any defects in the alignment of the cell.

[0071] Figure 3 and Figure 4 A side view of stacking inspection devices 200 and 300 for such cell units is shown schematically.

[0072] First, refer to Figure 3 Cell cells 210, 220 and 230 are stacked in a manner that is wound in one direction, such that a separator 240 is inserted between one or more cell cells 210, 220 and 230, thereby fabricating an electrode assembly.

[0073] At this time, the stacking inspection device 200 according to the present invention includes: camera units 251 and 252, which pass through the upper part of the cell batteries 210, 220 and 230 in the stacking direction, such as Figure 1 The system includes four corner points to generate an alignment image; and light irradiation units 261 and 262, which, when stacking cell batteries 210, 220, and 230, irradiate light at the top of cell batteries 210, 220, and 230 to the four corner points of cell batteries 210, 220, and 230 as the objects of inspection. Camera units 251 and 252 include sensors 271 and 272, which identify the light irradiated from light irradiation units 261 and 262 and determine whether there are defects in the alignment of cell batteries 210, 220, and 230.

[0074] Sensors 271 and 272 identify light irradiated from light irradiation units 261 and 262, and determine an alignment defect when light is detected passing through at least one of the four corner points.

[0075] At this time, the functions of camera units 251 and 252, light illumination units 261 and 262, and various sensors 271 and 272 are as follows: Figure 1 and Figure 2 The description is the same as in the previous one, except that the objects of inspection are cell 210, 220 and 230, rather than electrode plates.

[0076] Furthermore, the same applies to sensors 271 and 272 measuring the round-trip time of light emitted from light irradiation units 261 and 262. In this case, the stack inspection device may further include a measurement unit 280 that measures the location-based thickness of each cell battery 210, 220, and 230 based on the round-trip time of each light emitted from sensors 271 and 272.

[0077] Furthermore, the stacking inspection device may further include a control unit 290, which, when sensors 271 and 272 determine that there is an alignment defect, corrects the alignment value based on information received from sensors 271 and 272 and instructs the correction unit cells 210, 220 and 230 to stack the corrected cells. The control unit 290 determines that there is a defect when the difference in the reciprocating time of each light measured from sensors 271 and 272 is equal to or greater than a specific value, or when the deviation of the position-based thickness of each cell cell 210, 220 and 230 measured from measuring unit 280 is equal to or greater than a specific value.

[0078] In this case, thickness and Figure 1 The difference in thickness measurement between the stacking inspection device 100 and the cell 210, 220 and 230 is that the thickness of the cells is measured.

[0079] Currently, there is no equipment in electrode assembly manufacturing facilities capable of filtering out defects in the thickness portion after the manufacturing of cell units and the stacking or lamination processes of cell units, thus posing a risk of contamination with products of high thickness. According to this disclosure, since the thickness of cell units 210, 220, and 230 can also be measured, the aforementioned problem can be prevented.

[0080] Figure 3 Only the form in which cell cells 210, 220 and 230 are wound in one direction is shown, but it is self-evident that the stacking inspection device 200 according to this disclosure can be applied even when the cell cells are stacked in a Z-shaped fold with the separator film.

[0081] In addition, refer to Figure 4 The electrode assembly is manufactured in a stacked manner in which a separator 340 is inserted and stacked between one or more cell units 310, 320 and 330.

[0082] At this time, the stacking inspection device 300 according to the present disclosure may include: camera units 351 and 352, which are positioned at the upper part of the stacking direction of the cell batteries 310, 320 and 330, such as... Figure 1 The system includes four corner points of the outer perimeter to generate an alignment image; and light irradiation units 361 and 362, which, when stacking cell batteries 310, 320 and 330, irradiate light at the top of cell batteries 310, 320 and 330 to the four corner points of cell batteries 310, 320 and 330 as the objects of inspection. Camera units 351 and 352 include sensors 371 and 372, which identify the light irradiated from light irradiation units 361 and 362 and determine whether there are defects in the alignment of cell batteries 310, 320 and 330.

[0083] Sensors 371 and 372 can measure the reciprocating time of light irradiated from light irradiation units 361 and 362, and the stack inspection device 300 may further include a measurement unit 380, which measures the position-based thickness of each cell battery 310, 320 and 330 based on the reciprocating time of each light irradiated from sensors 371 and 372.

[0084] The stacking inspection device may further include a control unit 390, which, when sensors 371 and 372 determine that there is an alignment defect, corrects the alignment value based on information received from sensors 371 and 372 and instructs the correction unit to adjust the stacking position of cell batteries 310, 320 and 330. The control unit 390 determines that there is a defect when the difference in the round-trip time of each light measured from sensors 371 and 372 is equal to or greater than a specific value, or when the deviation of the position-based thickness of each cell battery 310, 320 and 330 measured from measuring unit 380 is equal to or greater than a specific value.

[0085] Based on the above, those skilled in the art will be able to make various applications and modifications within the scope of this disclosure.

[0086] [Reference Label Explanation]

[0087] 100, 200, 300: Stacking inspection equipment,

[0088] 110: First electrode plate, 120: Second electrode plate

[0089] 130, 340: diaphragm,

[0090] 210, 220, 230, 310, 320, 330: Single-cell batteries.

[0091] 240: Separating membrane,

[0092] 141, 142, 143, 144, 251, 252, 351, 352: Camera units.

[0093] 151, 152, 153, 154, 261, 262, 361, 362: Light illumination units.

[0094] 161, 162, 163, 164, 271, 272, 371, 372: Sensors.

[0095] 170, 280, 380: Measurement units

[0096] 180, 290, 390: Control unit.

[0097] Industrial applicability

[0098] As described above, the stacking inspection apparatus according to embodiments of this disclosure can inspect stacking alignment defects of electrode plates or cell batteries in real time by adding a light irradiation unit for irradiating light to the equipment used in existing processes and adding a sensor to the camera unit.

[0099] Therefore, without affecting the existing process flow, the time required for alignment or interval checks between the positive and negative electrodes during production can be reduced, and alignment defects can be significantly reduced, thereby improving product performance, thus improving product quality and increasing output.

[0100] Furthermore, since the thickness difference at each location of the electrode plate or cell can be measured using the light irradiation unit used in the stacking inspection equipment, loading defects with large thickness deviations at each location can be detected. Therefore, errors that occur when the operator measures directly can be minimized, and electrode plates or cells with loading defects or thickness defects can be detected and removed in advance, thereby further improving product quality.

Claims

1. A stacking inspection apparatus for electrode plates when a first electrode plate and a second electrode plate are stacked such that a diaphragm is inserted between the first electrode plate and the second electrode plate, the stacking inspection apparatus comprising: A camera unit generates an aligned image by capturing images of the four corner points of the outer periphery of the first electrode plate or the second electrode plate at the upper part of the stacking direction of the first electrode plate and the second electrode plate. and The light irradiation unit, when the first electrode plate and the second electrode plate are stacked, irradiates light at the upper part of the first electrode plate or the second electrode plate towards the four corner points of the first electrode plate and the second electrode plate being inspected, such that even if the first electrode plate or the second electrode plate is partially deviated from its stacked position in any direction (left, right, up, down), the light passes through. The camera unit includes a sensor that identifies light irradiated from the light irradiation unit and determines that the alignment of the first electrode plate and the second electrode plate is defective when the light is detected to pass through at least one of the four corner points.

2. The stacking inspection apparatus according to claim 1, wherein: The sensor measures the round-trip time of light emitted from the light irradiation unit.

3. The stacking inspection apparatus according to claim 2, further comprising: A measurement unit that measures the position-based thickness of each of the first and second electrode plates based on the round-trip time of each light measured from the sensor.

4. The stacking inspection apparatus according to claim 3, wherein: The stacking inspection device further includes a control unit that, when the sensor determines an alignment defect, corrects the alignment value based on information received from the sensor and instructs the correction of the stacking position of the first electrode plate or the second electrode plate. The control unit determines a defect when the difference in the reciprocating time of each light measured from the sensor is equal to or greater than a specific value, or when the position-based thickness deviation of each of the first and second electrode plates measured from the measuring unit is equal to or greater than a specific value.

5. A stacking inspection apparatus for cell cells when stacking cell cells such that a separator or membrane is inserted between one or more cell cells, the stacking inspection apparatus comprising: A camera unit generates an aligned image by photographing the four corner points of the outer periphery of the cell battery at the upper part of the stacking direction of the cell battery. and The light irradiation unit, when stacking the cell units, irradiates light from the top of the cell units onto the four corners of the cell unit being inspected, such that even if the cell unit is partially deviated from its stacking position in any direction (left, right, up, down), the light passes through. The camera unit includes a sensor that identifies light emanating from the light illuminating unit and determines that the alignment of the unit cell is defective when the light is detected passing through at least one of the four corner points.

6. The stacking inspection apparatus according to claim 5, wherein: The sensor measures the round-trip time of light emitted from the light irradiation unit.

7. The stacking inspection apparatus according to claim 6, further comprising: A measurement unit that measures the location-based thickness of each cell battery based on the round-trip time of each light measured from the sensor.

8. The stacking inspection apparatus according to claim 7, wherein: The stacking inspection device further includes a control unit that, when the sensor determines that there is an alignment defect, corrects the alignment value based on information received from the sensor and instructs the correction of the stacking position of the cell batteries. The control unit determines that there is a defect when the difference in the round-trip time of each light measured from the sensor is equal to or greater than a specific value, or when the deviation of the position-based thickness of each cell battery measured from the measuring unit is equal to or greater than a specific value.

9. The stacking inspection apparatus according to claim 5, wherein: The cell units are stacked such that the separator is rolled around the cell unit in one direction, or the cell units are stacked such that the separator is folded in a Z-shape, or the cell units are stacked such that the separator is inserted between the cell units and laminated.

Images