Apparatus and method for inspecting electrode stacking of secondary batteries

Abstract

The present invention relates to an electrode laminate inspection apparatus for a secondary battery, including a stack table on which a laminate including a plurality of positive electrodes, negative electrodes, and a separator disposed between the positive electrode and the negative electrode is placed, a fixing portion that fixes one surface of the laminate and includes at least one hole that exposes the laminate, and an imaging unit that images the laminate exposed through the hole.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0184173, filed with the Korean Intellectual Property Office on December 26, 2022, and all of its contents are incorporated herein by reference.

[0002] The present invention relates to an electrode stack inspection apparatus and inspection method for a secondary battery.

Background Art

[0003] Generally, a secondary battery, unlike a primary battery that cannot be charged, refers to a battery that can be charged and discharged, and such secondary batteries are widely used in the field of advanced electronic devices such as mobile phones, notebook computers, and camcorders.

[0004] The secondary battery can ensure stability through a stability test in which one side is crimped with a crimping machine to measure internal short circuits.

[0005] Secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is built into a cylindrical or prismatic metal battery case according to the shape of the battery case, and pouch-type batteries in which the electrode assembly is built into a pouch-type battery case made of an aluminum laminate sheet.

[0006] In a pouch-type battery, a laminate in which a positive electrode, a separator, and a negative electrode are laminated is heated and pressed to bond the positive electrode, negative electrode, and separator. When the laminate is pressed, the laminate is not fixed, so a twisting problem occurs. Therefore, after pressing the laminate, the quality of the electrode assembly is inspected to confirm whether the electrodes are laminated in a normal order and arrangement.

[0007] However, in the quality inspection of conventional pouch-type batteries, since the quality of the electrode assembly is inspected after the manufacturing of the electrode assembly is completed, if there are defects in the arrangement or order of the electrodes, the electrode assembly has to be discarded, resulting in a very large economic loss.

[0008] Conventionally, quality inspection of pouch-type batteries has had the problem that it cannot detect defects such as the arrangement of electrode plates and floating of lamination during the electrode lamination process. Summary of the Invention Problems to be Solved by the Invention

[0009] In view of the problems of the prior art described above, an object of the present invention is to provide an electrode lamination inspection apparatus and inspection method for a secondary battery that inspects the arrangement of electrodes and the floating of the separator and electrodes during the manufacturing process of an electrode assembly. Means for Solving the Problems

[0010] One embodiment of the present invention includes a stack table on which a laminate including a plurality of positive electrodes, negative electrodes, and a separator disposed between the positive electrode and the negative electrode is placed; a fixing portion that fixes the laminate and includes at least one hole that exposes the laminate; and an imaging unit that images the laminate exposed through the hole. An electrode lamination inspection apparatus for a secondary battery is provided.

[0011] Another embodiment of the present invention includes a laminate manufacturing step of supplying a plurality of positive electrodes and negative electrodes to a stack table and supplying a separator between the positive electrode and the negative electrode to manufacture a laminate; a laminate fixing step of fixing the laminate in the lamination direction using a fixing portion including at least one hole that exposes the laminate; and an imaging step of imaging the laminate exposed through the hole. An electrode lamination inspection method for a secondary battery is provided. Advantages of the Invention

[0012] The electrode lamination inspection apparatus and inspection method for a secondary battery according to an embodiment of the present invention can minimize the floating of the separator and electrodes by fixing the electrode assembly when a fixing portion provided with a hole that exposes an end portion of the electrode assembly inspects the arrangement of the electrodes. Brief Description of the Drawings

[0013] [Figure 1]This is a plan view showing a plane in which a fixing part according to one embodiment of the present invention is fixing a laminate. [Figure 2] This is a cross-sectional view showing the section A-A' in Figure 1. [Figure 3] This is a plan view showing a fixed part according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view showing an electrode assembly manufacturing apparatus according to one embodiment of the present invention. [Figure 5] This is a perspective view showing a separation membrane supply unit according to one embodiment of the present invention. [Figure 6] This is a fitted line graph showing the nx-th distance of each electrode in the laminate measured in the comparative example, and the nx-th distance actually measured by cutting a cross-section of the laminate. [Figure 7] This is a fitted line graph showing the nx-th distance of each electrode in the laminate measured in the example, and the nx-th distance actually measured by cutting a cross-section of the laminate. [Figure 8] This is a fitted line graph showing the relationship between the ny-th distance of each electrode in the laminate measured in the example and the ny-th distance actually measured by cutting a cross-section of the laminate. [Modes for carrying out the invention]

[0014] The detailed description of the present invention is intended to fully explain the invention to a person having ordinary skill in the art to which the invention pertains. Throughout the specification, where a part of the specification "includes" a component or "characterizes" a structure and shape, this means that, unless otherwise stated, it may include other components, structures and shapes, rather than excluding other components or other structures and shapes.

[0015] The present invention can be subjected to a variety of transformations and may have various embodiments, and specific embodiments are presented and described in detail in the detailed description. However, this should be understood not as an attempt to limit the scope of the invention by the embodiments, but rather as including all transformations, equivalents, or substitutions that fall within the spirit and technical scope of the present invention.

[0016] The present invention will be described in detail below with reference to the drawings. However, the drawings are for illustrative purposes only, and the scope of the present invention is not limited by the drawings.

[0017] Figure 1 is a plan view showing the plane in which the fixing part 20 according to one embodiment of the present invention is fixing the laminate S, Figure 2 is a cross-sectional view showing the cross section A-A' in Figure 1, and Figure 3 is a plan view showing the fixing part 20 according to one embodiment of the present invention.

[0018] The electrode stacking inspection apparatus 100 for secondary batteries according to the present invention includes a stack table 10, a fixing unit 20, and an imaging unit 30.

[0019] The stacking table 10 is supplied with a positive electrode, a negative electrode, and a separation membrane, and stacks them to produce and place a laminate. For example, a laminate in which multiple positive and negative electrodes are stacked on a zigzag-shaped separation membrane is placed on the table. Here, the laminate S is simply a stack of the separation membrane, positive electrode, and negative electrode, and the electrode assembly means that the laminate S is heated and pressurized so that the separation membrane and the positive and negative electrodes are attached or bonded together.

[0020] Furthermore, the laminate S of the present invention refers to the state before the separation membrane, positive electrode, and negative electrode are attached, and the number of layers of positive and negative electrodes can vary.

[0021] The electrode assembly includes a positive electrode, a negative electrode, and a separator membrane positioned between the positive and negative electrodes, and is a power generation element capable of charging and discharging.

[0022] The electrode assembly may include a stack-and-fold structure in which a negative electrode and a positive electrode are sequentially stacked between separation membranes supplied in a zigzag pattern.

[0023] The positive electrode may include a positive electrode current collector, a positive electrode active material portion, and a positive electrode blank portion. The positive electrode current collector may be a thin metal plate with excellent conductivity, such as aluminum (Al) foil.

[0024] The positive electrode is a positive electrode current collector on which one or more sides are coated with positive electrode active material. The area coated with positive electrode active material is the positive electrode active material area, and the area not coated with positive electrode active material is the positive electrode plain area. The positive electrode plain area does not have a positive electrode active material layer applied to it, and a first electrode tab can be joined to it.

[0025] The positive electrode active material may include lithium cobalt oxide, which has a high operating voltage and excellent capacity characteristics; lithium nickel oxide, which has high reversible capacity and facilitates the realization of large-capacity batteries; lithium nickel cobalt oxide, in which part of the nickel is replaced with cobalt; lithium nickel cobalt metal oxide, in which part of the nickel is replaced with manganese, cobalt, or aluminum; lithium manganese-based oxide, which has excellent thermal stability and is inexpensive; and lithium iron phosphate, which has excellent stability.

[0026] The negative electrode may include a negative electrode current collector, a negative electrode active material portion, and a negative electrode blank portion. The negative electrode current collector may be a thin metal plate with excellent conductivity, for example, containing copper (Cu) or nickel (Ni) foil.

[0027] The negative electrode is a negative electrode current collector with negative electrode active material coated on one or both sides. The negative electrode active material portion is formed by coating or applying the negative electrode active material, while the negative electrode plain portion is an area where the negative electrode current collector is exposed and the negative electrode active material is not coated or applied. The negative electrode plain portion is uncoated with negative electrode active material and can be used to bond a second electrode tab.

[0028] The negative electrode active material may be, for example, a carbon material such as crystalline carbon, amorphous carbon, carbon composite, or carbon fiber, or a lithium metal or lithium alloy. In this case, the negative electrode active material may further include, for example, non-graphite-based SiO (silica) or SiC (silicon carbide) for high-capacity design.

[0029] The first electrode tab and the second electrode tab transmit electrons collected by the current collector to the external circuit, and can protrude in directions opposite to each other relative to the electrode assembly of the jelly roll structure.

[0030] The separation membrane prevents internal short circuits that may occur when the positive and negative electrodes come into contact, and may contain a porous material to facilitate the movement of ions between the electrodes.

[0031] In one embodiment, the separation membrane may include a porous substrate layer. The substrate layer may include, for example, one selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP), and a copolymer of polyethylene (PE) and polypropylene (PP).

[0032] In other embodiments, the separation membrane may include an SRS (Safety Reinforced Separator) separation membrane. That is, the separation membrane may include a substrate layer made of a porous material, and a coating layer formed by coating the substrate layer with a mixed slurry of inorganic particles and a binder polymer. Preferably, the coating layer contains ceramic particles and has a uniform porous structure formed by the interstitial volume between the ceramic particles, which are the active layer components, along with the porous structure contained in the separation membrane substrate itself.

[0033] The coating layer may contain ceramic particles comprising at least one selected from the group consisting of alumina, silica, TiO2, SiC, and MgAl2O4. Including such a coating layer can enhance the safety of the electrode assembly. Furthermore, the coating layer may further contain a lithium salt.

[0034] The electrode stacking inspection apparatus 100 for secondary batteries according to the present invention may be included in an electrode assembly manufacturing apparatus. Figure 4 is a cross-sectional view showing an electrode assembly manufacturing apparatus 200 according to one embodiment of the present invention. The electrode assembly manufacturing apparatus 200 includes a stack table 10, a separation membrane supply unit 50, a first electrode supply unit, a second electrode supply unit, and a press unit (not shown). Therefore, the stack table 10 of the electrode stacking inspection apparatus 100 for secondary batteries may be the same as the stack table 10 of the electrode assembly manufacturing apparatus.

[0035] The stack table 10 has a first electrode 1, a separation membrane 4, and a second electrode 2 stacked alternately on one surface, and the stacked stack S is placed on top of it. The separation membrane 4 is folded in a zigzag pattern, and the first electrode 1, the separation membrane 4, and the second electrode 2 can be stacked in such a manner that the first electrode 1 and the second electrode 2 are alternately arranged between the folded separation membranes 4. Here, the first electrode 1 and the second electrode 2 may include a positive electrode and a negative electrode. For example, if the first electrode 1 is the positive electrode, the second electrode 2 may be the negative electrode, and if the first electrode 1 is the negative electrode, the second electrode 2 may be the positive electrode.

[0036] The stacking table 10 can stack the first electrode 1 and the second electrode 2 that are supplied to the stacking table 10 by rotation. Therefore, the electrode assembly manufacturing apparatus 200 according to the present invention may further include a rotating part (not shown) for rotating the stacking table 10.

[0037] In the electrode assembly manufacturing apparatus 200 according to the present invention, the first electrode supply unit may be located on one side of the stack table 10, or the second electrode supply unit may be located on the other side. In this case, the rotating unit can rotate the stack table 10 alternately in the direction of the first electrode supply unit and the direction of the second electrode supply unit.

[0038] For example, the separation membrane supply unit 50 may be located at the top of the stack table 10, i.e., in the stacking direction of the stacked material S, and the first electrode supply unit may be located on the left side and the second electrode supply unit on the right side with respect to the stacking direction of the stacked material S.

[0039] When the separation membrane 4 is supplied and placed on the stack table 10, and the rotating unit rotates the stack table to the left, the first electrode can be supplied to one side of the separation membrane 4. Simultaneously with the supply of the separation membrane 4, the rotating unit can rotate the stack table 10 to the right. At this time, the separation membrane 4 can cover the bottom, right side, and top surface of the first electrode 1, and the second electrode 2 can be supplied to the top surface of the first electrode 1 where the separation membrane 4 is located.

[0040] By repeating the above process, the separation membrane 4 can be provided in a form in which the left and right sides of each layer are alternately opened.

[0041] Figure 5 is a perspective view showing a separation membrane supply unit 50 according to one embodiment of the present invention. The separation membrane supply unit 50 may include a separation membrane heating unit 51 that has a passage through which the separation membrane 4 passes and heats the separation membrane 4 as it passes.

[0042] The separation membrane heating unit 51 may include a pair of bodies (not shown) and a separation membrane heater (not shown) for heating the bodies. The pair of bodies may be positioned at a predetermined distance apart from each other so that the separation membrane 4 can pass through. Here, the separation membrane 4 can be heated in a non-contact manner by passing through, for example, the separation membrane heating unit 51 without contact. On the other hand, the bodies may be formed in the shape of, for example, a rectangular block.

[0043] On the other hand, the separation membrane supply unit 50 may further include a separation membrane roll 52 on which the separation membrane 4 is wound. Here, the separation membrane 4 wound on the separation membrane roll 52 can be gradually unwound, pass through the separation membrane heating unit 51, and be supplied to the stack table 10. For example, the separation membrane supply unit 50 may be located above the stack table 10.

[0044] The first electrode supply unit supplies the first electrode 1 to the stack table 10, allowing the first electrode 1 to be stacked on the stack table 10.

[0045] The first electrode supply unit may include a first electrode placement table 61 on which the first electrode 1 is placed before it is stacked on the stack table 10.

[0046] The first electrode supply unit may further include a first electrode roll 63, a first cutter 64, a first conveyor belt 65, and a first electrode supply head 66.

[0047] The first electrode supply unit allows the first electrode 1, which is wound in a sheet form on the first electrode roll 63, to be gradually unwound and supplied to the first electrode mounting table 61 side, and the first cutter 64 can cut the first electrode 1 supplied on the first electrode roll 63 side to a predetermined length.

[0048] The first electrode 1, cut by the first cutter 64, is supplied to the first conveyor belt 65, which moves the first electrode 1 toward the first electrode placement table 61. The first electrode supply head 66 then vacuum-suctions the first electrode 1, which is placed on the first conveyor belt 65, and places it on the first electrode placement table 61.

[0049] Here, the first cutter 64 can cut the sheet-shaped first electrode 1 such that a first electrode tab protrudes from its end.

[0050] Furthermore, the first electrode supply unit may also include a first suction head 62 and a first moving unit 67.

[0051] The first suction head 62 can vacuum-suction the first electrode 1 placed on the first electrode mounting table 61. The first suction head 62 includes a vacuum suction section (not shown) at its bottom, which can suck in the first electrode 1 through the vacuum suction port and fix the first electrode 1 to the bottom surface of the first suction head 62. Here, the first suction head 62 may have a passage formed inside that connects the vacuum suction port to a vacuum suction device (not shown).

[0052] The first moving unit 67 can move the first suction head 62 to the stacking table 10 so that the first suction head 62 can stack the first electrodes 1, which are placed on the first electrode placement table 61, onto the stacking table 10.

[0053] The second electrode supply unit supplies the second electrode 2 to the stack table 10, allowing the second electrode 2 to be stacked on the stack table 10.

[0054] The second electrode supply unit may include a second electrode placement table 71 on which the second electrode 2 is placed before it is stacked on the stack table 10.

[0055] The second electrode supply unit may further include a second electrode roll 73 on which the second electrode 2 is wound into a sheet, a second cutter 74 that cuts the sheet-shaped second electrode 2 wound on the second electrode roll 73 at predetermined intervals when it is unwound and supplied, forming second electrodes 2 of a predetermined size, a second conveyor belt 75 that moves the second electrodes 2 cut by the second cutter 74, and a second electrode supply head 76 that vacuum-suctions the second electrodes 2 being transported by the second conveyor belt 75 and places them on a second electrode placement table 71.

[0056] Here, the second cutter 74 can cut the sheet-shaped second electrode 2 such that a second electrode tab protrudes from its end.

[0057] Furthermore, the second electrode supply unit may include a second suction head 72 for vacuum-suctioning the second electrode 2 placed on the second electrode mounting table 71, and a second moving unit 77 that can move the second suction head 72 to the stacking table 10 so that the second electrode 2 placed on the second electrode mounting table 71 can be stacked on the stacking table 10.

[0058] The second suction head 72 may include a vacuum intake port (not shown) that draws air into the bottom surface on which the second electrode 2 is placed, so that the second electrode 2 is fixed to the bottom surface of the second suction head 72.

[0059] In this case, the rotating part according to one embodiment of the present invention can rotate the stack table 10 so that it faces the first suction head 62 when stacking the first electrode 1, and can rotate the stack table 10 so that it faces the second suction head 72 when stacking the second electrode 2.

[0060] The fixing portion 20 includes at least one hole 21, 22 for fixing the laminate S and exposing the laminate S. The fixing portion 20 can be fixed by applying pressure to one surface of the laminate S in the lamination direction of the laminate S.

[0061] Referring to Figures 1 and 3, the fixing portion 20 may include a first hole 21 that exposes the line along which the separation membrane 4 is folded, and a second hole 22 that exposes a line perpendicular to the line along which the separation membrane is folded.

[0062] The laminate S according to the present invention may include two long sides which are the sides or ends from which the separation film is folded, and two short sides which are perpendicular to the long sides and which are the sides or ends from which the electrode tabs protrude.

[0063] In one embodiment, the separation membrane 4 or laminate S stacked on the stack table 10 includes a first end s1, a second end s2 facing the first end s1, a third end s3 and a fourth end s4 connecting the first end s1 and the second end s2.

[0064] The first hole 21 of the fixing part 20 can expose the first end s1 or the second end s2, which is the long side of the laminate S, and the second hole 22 can expose the third end s3 or the fourth end s4, which is the short side of the laminate S.

[0065] Multiple fixing parts 20 may be included. The fixing parts 20 can extend in the longitudinal direction of the laminate S to fix the laminate S. Furthermore, two fixing parts 20 may be provided as a pair.

[0066] Furthermore, one of the pair of fixing parts 20 may extend from the third end s3 in the longitudinal direction of the laminate S, and the other fixing part 20 may extend from the fourth end s4 in the longitudinal direction of the laminate S. The pair of fixing parts 20 may also be positioned at a distance from each other.

[0067] The fixing portion 20 may include two pairs. One pair of fixing portions 20 may be positioned adjacent to the first end s1, and the other pair of fixing portions 20 may be positioned adjacent to the second end s2. Alternatively, one end of one pair of fixing portions 20 may be positioned collinear with the first end s1, and the other pair of fixing portions 20 may be positioned collinear with the second end s2.

[0068] The first hole 21 is not limited in shape as long as it can expose the line along which the separation membrane is folded, but it may be provided in a square or rectangular shape, for example. The second hole 22 is not limited in shape as long as it can expose a line perpendicular to the line along which the separation membrane is folded, but it may be provided in a circular shape, for example.

[0069] The imaging unit 30 can photograph the laminate S and stack table exposed through the holes 21 and 22, and the secondary battery electrode stacking inspection apparatus 100 according to the present invention may further include a determination unit 40 that receives the data captured by the imaging unit 30, analyzes the positions of the positive electrode, negative electrode and separator membrane 4, and determines misalignment of the positive electrode, negative electrode and separator membrane.

[0070] The imaging unit 30 may image the first hole 21 and the second hole 22 together with the stack table, or it may image the first hole 21, the second hole 22, and the stack table all together. The imaging unit 30 can then image the first hole 21 and the second hole 22 each time that a separation film 4 is stacked on one side of multiple positive and negative electrodes to confirm the alignment of the positive electrode, negative electrode, and separation film in each layer.

[0071] The determination unit 40 measures the distance between the first end s1 or second end s2 of the separation membrane located in the first hole 21 and the end of the stack table 10 that is parallel to the first end s1 or second end s2.

[0072] Alternatively, the determination unit 40 measures the distance between the third end s3 or fourth end s4 of the separation membrane located in the second hole 22 and the end of the stack table 10 parallel to the third end s3 or fourth end s4.

[0073] Alternatively, the determination unit 40 measures the distance between the first end s1 or the second end s2 and the end of the stack table 10 parallel to the first end s1 or the second end s2, and the distance between the third end s3 or the fourth end s4 and the end of the stack table 10 parallel to the third end s3 or the fourth end s4.

[0074] In one embodiment, the secondary battery electrode stacking inspection device 100 includes two pairs of fixing parts 20, the first pair of fixing parts 20 being located adjacent to the first end s1 and fixing the negative electrode and the separator membrane, and the second pair of fixing parts 20 being located adjacent to the second end s2 and fixing the positive electrode and the separator membrane.

[0075] After the negative electrode lamination, separation film lamination, and folding, the first pair of fixing parts 20 fix the laminate S, and the imaging unit 30 images the first hole 21 and the second hole 22 formed in the first pair of fixing parts 20. Subsequently, the determination unit 40 receives the image captured by the imaging unit 30 and measures the distance between the first end s1, which is captured together with the first hole 21 on the captured image, and the end of the stack table parallel to the first end s1. Then, the determination unit 40 measures the distance between the second hole and the captured third end s3 and the end of the stack table parallel to the third end s3.

[0076] The determination unit 40 can confirm the alignment of the positive electrode, negative electrode, or separation membrane 4 by comparing the measured distance between the separation membrane 4 and the edge of the stack table with a previously set reference value.

[0077] The distance between the first end portion s1 or the second end portion s2 exposed through the first hole 21 of the fixing portion 20 that fixes the n-th stacked positive electrode and the separator 4 or the negative electrode and the separator 4 and the end portion of the stack table is the n-th x distance, and the distance between the first end portion s1 or the second end portion s2 exposed through the first hole 21 of the fixing portion 20 that fixes the (n + 1)-th stacked positive electrode and the separator or the negative electrode and the separator and the end portion of the stack table is the (n + 1)-th x distance.

[0078] And the distance between the third end portion s3 or the fourth end portion s4 exposed through the second hole 22 of the fixing portion 20 that fixes the n-th stacked positive electrode and the separator 4 or the negative electrode and the separator 4 and the end portion of the stack table is the n-th y distance, and the distance between the third end portion s3 or the fourth end portion s4 exposed through the second hole 22 of the fixing portion 20 that fixes the (n + 1)-th stacked positive electrode and the separator 4 or the negative electrode and the separator 4 and the end portion of the stack table is the (n + 1)-th y distance.

[0079] The determination unit 40 can confirm the alignment of the positive electrode, the negative electrode, or the separator 4 by comparing the n-th x distance, the (n + 1)-th x distance, the n-th y distance, and the (n + 1)-th y distance with a preset reference value. Specifically, the determination unit 40 compares the difference between the n-th x distance and the (n + 1)-th x distance or the difference between the n-th y distance and the (n + 1)-th y distance. If the difference is less than or equal to the reference value, it is normal. If the difference between the n-th x distance and the (n + 1)-th x distance or the difference between the n-th y distance and the (n + 1)-th y distance exceeds the reference value, it can be determined that there is misalignment.

[0080] Or, the determination unit 40 compares the n-th x distance and the n-th yIf the distance is less than or equal to a previously set reference value, it can be determined to be normal; if it exceeds the reference value, it can be determined to be misaligned. In other words, the previously set reference value is the distance between the first end s1 or the second end s2 and the end of the stack table, or the nth x Distance and the (n+1) x The difference from the distance or the nth y Distance and the (n+1) y This could be an error value within the normal range for distance.

[0081] In one embodiment, the reference value is the distance between the positive electrode, negative electrode, or the end of the separation membrane 4 and the end of the stack table, then the nth x The reference value for distance may be 5 mm or less. Preferably, the nth x The reference value for distance may be 3 mm or less, and more preferably 2 mm or less. y The reference value for distance may be 10 mm or less. Preferably, the nth y The standard distance is 6 mm or less, and more preferably 4 mm or less.

[0082] nth measured by the determination unit 40 x Distance and nth y If one or more of the distances exceed the reference value, the determination unit 40 can determine that the electrodes and the separation membrane are misaligned.

[0083] The secondary battery electrode stacking inspection apparatus 100 according to the present invention may further include a control unit (not shown). The control unit can control the fixing unit 20, the imaging unit 30, the stacking table, and the like.

[0084] For example, the control unit can control the fixing and release of the laminated material S of the fixing unit 20, and can control the shooting position of the shooting unit 30.

[0085] If the electrode stacking inspection apparatus 100 for secondary batteries according to the present invention is included in an electrode assembly manufacturing apparatus, the electrode assembly manufacturing apparatus may further include an electrode realignment unit (not shown).

[0086] If the determination unit 40 determines that the electrode stacking is faulty, the electrode realignment unit can re-stack the faulty electrodes. In one embodiment, the control unit can release the stacked material S from the fixing unit 20 and move the stack table to the electrode realignment unit. Alternatively, the control unit can move the electrode realignment unit to the stack table and re-stack the electrodes.

[0087] A secondary battery electrode stacking inspection method includes a stacking manufacturing step S10 in which a plurality of positive and negative electrodes are supplied to a stacking table and a separation film is supplied between the positive and negative electrodes to manufacture a stacking structure; a stacking fixing step S20 in which the stacking structure is fixed in the stacking direction using a fixing part that includes at least one hole that exposes the stacking structure; and an imaging step S30 in which the stacking structure exposed through the hole is photographed.

[0088] In the laminate fixing step S20, after the positive or negative electrode is supplied to the stack table, the laminate can be fixed each time a separation film is laminated on one side of the positive or negative electrode.

[0089] In the imaging stage S30, the holes in the fixed part and the stack table can be imaged. In this case, the holes may include a first hole that exposes the line along which the separation membrane is folded, and a second hole that exposes a line perpendicular to the line along which the separation membrane is folded.

[0090] In the imaging stage S30, the first hole and the stacking table and the second hole and the stacking table can be imaged separately, or the first hole, the second hole, and the stacking table can all be imaged at once.

[0091] The method for inspecting the electrode stacking of a secondary battery further includes a judgment step S40 in which the presence or absence of stacking defects in the positive electrode, negative electrode, and separator film is determined based on the data captured in the imaging step S30.

[0092] In the determination step S40, the distance between the first or second end of the separation membrane located in the first hole and the end of the stack table parallel to the first or second end is measured, or the distance between the third or fourth end of the separation membrane located in the second hole and the end of the stack table parallel to the third or fourth end is measured. Alternatively, in the determination step S40, the distance between the first or second end and the end of the stack table parallel to the first or second end and the distance between the third or fourth end and the end of the stack table parallel to the third or fourth end is measured.

[0093] The determination step S40 is the nth distance, which is the distance between the first or second end of the nth stacked separation membrane and the end of the stack table. x The distance is compared with a previously set reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane, or the nth distance is the distance between the third or fourth end of the nth stacked separation membrane and the end of the stack table. y By comparing the distance with a previously set reference value, it is possible to determine if the negative electrode, the positive electrode, and the separation membrane are misaligned.

[0094] The method for inspecting the electrode stacking of secondary batteries can be described by referring to the description of the electrode stacking inspection device for secondary batteries.

[0095] While preferred embodiments of the present invention have been described above with reference to those who are ordinary skill in the art, it should be understood that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as set forth in the appended claims. [Examples]

[0096] [Comparative Example] The comparative example utilizes a conventional electrode stacking inspection device and inspection method for secondary batteries, and the fixing part included in the electrode stacking inspection device for secondary batteries does not contain holes. The electrode stacking inspection method for secondary batteries involves stacking the electrodes and separation film, and then fixing the four corners of the stack using four fixing parts. Before photographing the electrode stacking state with the imaging unit, the fixing parts are released and the stack is photographed. The judgment unit uses the image captured by the imaging unit to determine the nth x Distance and the nth y The distance is measured and compared to a reference value to determine whether there are any defects in the electrode stacking.

[0097] [Examples] The example uses the electrode stacking inspection apparatus and inspection method for secondary batteries according to the present invention to determine whether or not there are defects in the electrode stacking.

[0098] Figure 6 shows the nth electrode of each electrode in the laminate measured in the comparative example. x The distance and the nth measurement were actually taken by cutting the cross-section of the laminate. x This is a line graph of the fit against distance, and Figure 7 shows the nth electrode of each electrode in the laminate measured in the example. x The distance and the nth measurement were actually taken by cutting the cross-section of the laminate. x This is a line graph of the fit against distance, and Figure 8 shows the nth electrode of each electrode in the laminate measured in the example. y The distance and the nth measurement were actually taken by cutting the cross-section of the laminate. y This is a line graph adapted to distance.

[0099] nth x Distance measurements were taken at two locations adjacent to the electrode tabs at both the first and second ends. x The distance measurement locations are designated as x1, x2, x3, and x4 in the order of the upper right, lower right, upper left, and lower left of the laminate shown in Figures 6 and 7. Then, the nth y Distance measurements were taken at two locations each at the third and fourth ends, and these were designated as y1, y2, y3, and y4 in the order of upper right, lower right, upper left, and lower left of the laminate shown in Figure 8.

[0100] The fitting line graphs in Figures 6 and 7 show the nth measurement taken in the imaging unit and the judgment unit. xThe distance was plotted on the x-axis, and the nth measurement was taken by cutting a cross-section of the laminate. x The graph was created with distance as the y-axis. Then, the regression equation was calculated using linear regression analysis with the aforementioned variables. The calculated regression equation differed for each location, and the regression equation for each location is plotted on the graph. The R-squared value (R) indicates the confidence level of the regression equation. 2 ) are also shown in the graph for each position.

[0101] Referring to Figure 6, the comparative example is the nth measured by the judgment unit. x The nth term relative to distance x It can be seen that the distribution of distances spreads widely relative to the fitted line. In other words, the reliability of the fitted line of the comparative example, or in other words, the R-squared value (R) of the comparative example, is... 2 The fact that it is less than 60% indicates a low level of confidence.

[0102] Referring to Figures 7 and 8, the embodiment shows the R squared value (R 2 The accuracy rate is 64% or higher, indicating a high level of reliability in the fitting lines. In other words, after fixing the laminate with the fixing part, the nth measurement was taken through the hole. x Distance and nth y The distance is the nth measured distance. x Distance and nth y It can be confirmed that the values ​​are similar to distance values ​​and therefore reliable.

[0103] [Table 1]

[0104] [Table 2]

[0105] Tables 1 and 2 above show the nth measurement using the electrode stacking inspection apparatus for secondary batteries according to the present invention. x Distance and nth y The distance and the nth measurement obtained by cutting the cross-section of the laminate x Distance and nth y This table shows the mean distance, standard deviation σ, process capability Cp, and Cpk.

[0106] Cp (Capability of Precess) represents how much the population measurement results between the upper and lower limits are dispersed at the median. In Tables 1 and 2, the upper and lower limits of Cp are given for each stratum. x Distance and nth y The Cp value represents the highest and lowest values ​​on the x-axis (distance). The median, on the other hand, represents the y-axis value (number of measurements at the center of the x-axis, or mean). If the Cp value is greater than 1, it means that the measurements of the population are clustered around the median.

[0107] Furthermore, Cpk (Capability of Precess Katayori) represents the degree of slope of the median. In other words, it indicates the extent to which the median slopes towards the upper or lower limit.

[0108] Referring to Tables 1 and 2, the nth (vision measurement) was measured using the electrode stacking inspection device for secondary batteries according to the present invention. x Distance and nth y The distance was measured through the cross-section of the laminate. x Distance and nth y It can be seen that this is similar to distance.

[0109] Furthermore, the standard deviation and Cpk value are low, and Cp is high, and the nth x Distance and nth y It can be seen that the distances are clustered around the standard value. [Explanation of Symbols]

[0110] 100 ···Electrode stacking inspection device for secondary batteries 200...Electrode assembly manufacturing equipment 10 ···Stackable Table 20...Fixed part 21...1st hole 22...2nd hole 30 ···Photography Department 40 ···Judgment Department 50...Separation membrane supply section 51 ···Separation membrane heating section 52 ···Separation membrane roll 61 ···First electrode mounting table 62 ···First suction head 63 ···First electrode roll 64 ···First Cutter 65 ···First conveyor belt 66 ···First electrode supply head 67 ···First Mobile Unit 71 ···Second electrode mounting table 72 ···Second suction head 73 ···Second electrode roll 74 ···Second Cutter 75 ···Second conveyor belt 76 ···Second electrode supply head 77 ···Second Mobile Unit 1...1st electrode 2...Second electrode 4...Separation membrane S ···Laminate s1...1st end s2...Second end s3...Third end s4...4th end

Claims

1. A stack table on which a laminate comprising multiple positive electrodes, negative electrodes, and a separation membrane placed between the positive and negative electrodes is placed; A fixing portion that fixes one side of the laminate and includes at least one hole that exposes the laminate; and A camera unit for photographing the laminate exposed through the hole; Includes, The aforementioned fixing portion includes a plurality of parts, with two positioned in pairs along the longitudinal direction of the laminate. The aforementioned fixing part includes two pairs, and the two pairs of fixing parts alternately fix the laminate. A device for inspecting the stacking of electrodes in secondary batteries.

2. The electrode stacking inspection apparatus for a secondary battery according to claim 1, wherein the imaging unit takes an image each time the plurality of positive electrodes and negative electrodes are stacked.

3. The separation membrane includes a first end, a second end facing the first end, a third end connecting the first end and the second end, and a fourth end. The electrode stacking inspection apparatus for a secondary battery according to claim 1, wherein the fixing portion includes a first hole that exposes the first end or the second end, and a second hole that exposes the third end or the fourth end.

4. The electrode stacking inspection apparatus for a secondary battery according to claim 3, wherein the imaging unit images the first hole, the second hole, and the stacking table.

5. The electrode stacking inspection apparatus for a secondary battery according to claim 3, further comprising a determination unit that receives data captured by the imaging unit, analyzes the positions of the positive electrode, the negative electrode, and the separation membrane, and determines misalignment of the positive electrode, the negative electrode, and the separation membrane.

6. The electrode stacking inspection apparatus for a secondary battery according to claim 5, wherein the determination unit measures the distance between the first end or second end of the separation membrane exposed through the first hole and the end of the stack table parallel to the first end or second end.

7. The determination unit determines the nth distance, which is the distance between the first or second end of the nth stacked separation membrane and the end of the stack table. ｘ The electrode stacking inspection apparatus for a secondary battery according to claim 6, which determines misalignment of the negative electrode, the positive electrode, and the separation membrane by comparing the distance with a previously set reference value.

8. The electrode stacking inspection apparatus for a secondary battery according to claim 5, wherein the determination unit measures the distance between the third or fourth end of the separation membrane exposed through the second hole and the end of the stack table parallel to the third or fourth end.

9. The determination unit determines the nth distance, which is the distance between the third or fourth end of the nth stacked separation membrane and the end of the stack table. ｙ The electrode stacking inspection apparatus for a secondary battery according to claim 8, which determines misalignment of the negative electrode, the positive electrode, and the separation membrane by comparing the distance with a previously set reference value.

10. A laminate manufacturing step involves supplying multiple positive and negative electrodes to a stack table and supplying a separation membrane between the positive and negative electrodes to manufacture a laminate; A laminate fixing step of fixing the laminate in the stacking direction using a fixing portion that includes at least one hole that exposes the laminate; and A photographic step in which the laminate exposed through the hole is photographed; A method for inspecting the electrode stacking of secondary batteries, including the method described above.

11. The electrode stacking inspection method for a secondary battery according to claim 10, wherein the stacking fixing step and the imaging step fix the stack each time the separation film is supplied to one side of the positive electrode and the negative electrode, and the holes in the fixing part and the stack table are photographed.

12. The separation membrane includes a first end, a second end facing the first end, a third end connecting the first end and the second end, and a fourth end. The method for inspecting electrode stacking of a secondary battery according to claim 10, wherein in the stacking fixing step, the fixing portion includes a first hole that exposes the first end or the second end and a second hole that exposes the third end or the fourth end.

13. The method for inspecting electrode stacking of a secondary battery according to claim 12, wherein the aforementioned imaging step involves imaging the first hole, the second hole, and the stack table.

14. The method for inspecting electrode stacking of a secondary battery according to claim 12, further comprising a determination step of analyzing the positions of the positive electrode, the negative electrode, and the separation membrane based on the captured data to determine misalignment of the positive electrode, the negative electrode, and the separation membrane.

15. The method for inspecting electrode stacking of a secondary battery according to claim 14, wherein the determination step involves measuring the distance between the first or second end of the separation membrane exposed through the first hole and the end of the stack table parallel to the first or second end.

16. The method for inspecting electrode stacking of a secondary battery according to claim 15, wherein the determination step involves comparing the nxth distance, which is the distance between the first or second end of the nth stacked separator membrane and the end of the stack table, with a previously set reference value to determine misalignment of the negative electrode, the positive electrode, and the separator membrane.

17. The method for inspecting electrode stacking of a secondary battery according to any one of claims 14 to 16, wherein the determination step involves measuring the distance between the third or fourth end of the separation membrane exposed through the second hole and the end of the stack table parallel to the third or fourth end.

18. The aforementioned determination step is the nth distance, which is the distance between the third or fourth end of the nth stacked separation membrane and the end of the stack table. ｙ A method for inspecting electrode stacking of a secondary battery according to claim 17, comprising comparing a distance with a previously set reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane.

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