Secondary battery electrode stack inspection apparatus and inspection method

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 content is incorporated herein by reference.

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

Background Art

[0003] Generally, a secondary battery, unlike a primary battery that cannot be charged, is 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] A 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 pressurized to bond the positive electrode, the negative electrode, and the separator. When the laminate is pressurized in a pouch-type battery, since the laminate is not fixed, a twisting problem occurs. Therefore, after pressurizing the laminate, the quality of the electrode assembly is inspected to confirm whether the electrodes are laminated in the correct 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 manufacture 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] However, the quality inspection of conventional pouch-type batteries had a problem in that it could not detect defects such as the arrangement of electrode plates or the floating of laminations 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 in 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 part that fixes the laminate and includes at least one hole that exposes the laminate; and an imaging part 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 part 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. EFFECTS 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 the fixing part having a hole that exposes the end of the electrode assembly inspects the arrangement of the electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0014] The detailed description of the present invention is for completely explaining the present invention to those having ordinary knowledge in the technical field to which the present invention belongs. Throughout the specification, when a certain part includes a certain component or a certain structure and shape is a "feature", this means that, unless otherwise stated, other components, structures and shapes may be included, rather than excluding other components or other structures and shapes.

[0015] The present invention can be subjected to various conversions, can have various embodiments, and specific embodiments are presented for detailed description. However, this is not intended to limit the content of the invention by the embodiments, and it should be understood that it includes all conversions, equivalents or alternatives included in the idea and technical scope of the present invention.

[0016] Hereinafter, the present invention will be described in detail 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] FIG. 1 is a plan view showing a plane in which the fixing portion 20 according to an embodiment of the present invention fixes the laminate S, FIG. 2 is a cross-sectional view showing a cross-section taken along line A-A' of FIG. 1, and FIG. 3 is a plan view showing the fixing portion 20 according to an embodiment of the present invention.

[0018] The electrode laminate inspection apparatus 100 according to the present invention includes a stack table 10, a fixing portion 20, and a photographing portion 30.

[0019] The stack table 10 supplies, stacks a positive electrode, a negative electrode, and a separator, and manufactures and places a laminate. For example, a laminate in which a plurality of positive electrodes and negative electrodes are stacked on a zigzag-shaped separator is placed. Here, the laminate S is a simple stack of a separator, a positive electrode, and a negative electrode, and the electrode assembly means a product obtained by heating and pressing the laminate S so that the separator is attached or adhered to the positive electrode and the negative electrode.

[0020] And the laminate S of the present invention means before the separator is attached to the positive electrode and the negative electrode, and the number of stacked positive and negative electrodes can be various.

[0021] The electrode assembly includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, 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 separators supplied in a zigzag form.

[0023] The positive electrode may include a positive electrode current collector, a positive electrode active material portion, and a positive electrode non-woven portion. The positive electrode current collector is a metal thin plate having excellent conductivity, and may include, for example, aluminum (Al) foil.

[0024] The positive electrode is one in which a positive electrode active material is coated on one or more of both sides of a positive electrode current collector. The region where the positive electrode active material is coated is the positive electrode active material portion, and the region where the positive electrode active material is not coated is the positive electrode plain portion. The positive electrode plain portion has no positive electrode active material layer coated thereon and can be joined with a first electrode tab.

[0025] The positive electrode active material may include lithium cobalt oxide with a high working voltage and excellent capacity characteristics, lithium nickel oxide with a high reversible capacity and easy to realize a large-capacity battery, lithium nickel cobalt oxide in which part of nickel is replaced by cobalt, lithium nickel cobalt metal oxide in which part of nickel is replaced by manganese, cobalt or aluminum, lithium manganese-based oxide with excellent thermal stability and low cost, lithium iron phosphate with excellent stability, etc.

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

[0027] The negative electrode is one in which a negative electrode active material is coated on one or both sides of a negative electrode current collector. The negative electrode active material portion is formed by coating or applying a negative electrode active material, and the negative electrode plain portion is a region where the negative electrode active material is not coated or applied and the negative electrode current collector is exposed. The negative electrode plain portion has no negative electrode active material coated thereon and can be joined with 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, carbon fiber, lithium metal or lithium alloy. At this time, for high-capacity design, the negative electrode active material may further include, for example, non-graphite-based SiO (silica) or SiC (silicon carbide).

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

[0030] The separator prevents an internal short circuit that may occur when the positive electrode and the negative electrode come into contact, and may contain a porous material so that the movement of ions between the electrodes becomes smooth.

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

[0032] In another embodiment, the separator may include an SRS (Safety Reinforced Separator) separator. That is, the separator may include a base layer of a porous material and a coating layer formed by coating a mixed slurry in which inorganic particles and a binder polymer are mixed on the base layer. Preferably, the coating layer contains ceramic particles and has a uniform pore structure formed by the interstitial volume between the ceramic particles, which are the active layer components, together with the pore structure contained in the separator base itself.

[0033] The coating layer may include ceramic particles including at least one selected from the group consisting of alumina, silica, TiO2, SiC, and MgAl2O4. By including such a coating layer, the safety of the electrode assembly can be enhanced. And the coating layer may further contain a lithium salt.

[0034] The electrode stack inspection device 100 for a secondary battery according to the present invention may be included in an electrode assembly manufacturing device. FIG. 4 is a cross-sectional view showing an electrode assembly manufacturing device 200 according to an embodiment of the present invention. The electrode assembly manufacturing device 200 includes a stack table 10, a separator 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 stack inspection device 100 for a secondary battery may be the same as the stack table 10 of the electrode assembly manufacturing device.

[0035] The stack table 10 has a structure where the first electrode 1, the separator 4, and the second electrode 2 are alternately stacked on one surface, and the stacked laminate S is placed thereon. The separator 4 is folded in a zigzag pattern, and the first electrode 1 and the second electrode 2 are alternately arranged between the folded separators 4 so that the first electrode 1, the separator 4, and the second electrode 2 can be stacked. Here, the first electrode 1 and the second electrode 2 may include a positive electrode and a negative electrode. For example, when the first electrode 1 is a positive electrode, the second electrode 2 may be a negative electrode, and when the first electrode 1 is a negative electrode, the second electrode 2 may be a positive electrode.

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

[0037] In the electrode assembly manufacturing device 200 according to the present invention, the first electrode supply unit may be located on one side of the stack table 10, and the second electrode supply unit may be located on the other side. At this time, 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 separator supply unit 50 may be located above the stack table 10, that is, in the stacking direction of the laminate S. Based on the stacking direction of the laminate S, the first electrode supply unit may be located on the left side and the second electrode supply unit may be located on the right side.

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

[0040] When the above process is repeated, the separation membrane 4 can be provided in a form in which the left / right side surfaces are alternately opened for each layer.

[0041] FIG. 5 is a perspective view showing a separation membrane supply unit 50 according to an embodiment of the present invention. The separation membrane supply unit 50 may include a separation membrane heating unit 51 in which a passage through which the separation membrane 4 passes is formed and which heats the passing separation membrane 4.

[0042] The separation membrane heating unit 51 may include a pair of main bodies (not shown) and a separation membrane heater (not shown) that heats the main bodies. The pair of main bodies may be positioned at a predetermined distance from each other so that the separation membrane 4 can pass through. Here, the separation membrane 4 can pass through the separation membrane heating unit 51 in a non-contact manner, for example, and the separation membrane 4 can be heated in a non-contact method. On the other hand, the main body may be formed in a rectangular block form, for example.

[0043] On the other hand, the separation membrane supply unit 50 may further include a separation membrane roll 52 around which the separation membrane 4 is wound. Here, the separation membrane 4 wound around 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 can supply the first electrode 1 to the stack table 10 side and stack the first electrode 1 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 being stacked on the stack table 10.

[0046] And 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] In the first electrode supply unit, the first electrode 1 wound in a sheet form on the first electrode roll 63 can be gradually unwound and supplied to the side of the first electrode placement table 61. The first cutter 64 can cut the first electrode 1 supplied from the first electrode roll 63 side at a preset length.

[0048] The first electrode 1 cut by the first cutter 64 is supplied to the first conveyor belt 65, and the first conveyor belt 65 can move the first electrode 1 to the side of the first electrode placement table 61. Then, the first electrode supply head 66 can vacuum-adsorb the first electrode 1 placed on the first conveyor belt 65 and place it on the first electrode placement table 61.

[0049] Here, when cutting the first electrode 1 in sheet form, the first cutter 64 can cut it so that a first electrode tab protrudes from the end.

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

[0051] The first suction head 62 can vacuum-suck the first electrode 1 placed on the first electrode placement table 61. The first suction head 62 includes a vacuum suction part (not shown) on the bottom surface, and can suck 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 for connecting the vacuum suction port and 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 electrode 1 placed on the first electrode placement table 61 on the stacking table 10.

[0053] The second electrode supply unit can supply the second electrode 2 to the side of the stacking table 10 and stack the second electrode 2 on the stacking 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 being stacked on the stacking table 10.

[0055] Then, the second electrode supply unit further includes a second electrode roll 73 on which the second electrode 2 is wound in a sheet form, a second cutter 74 that cuts the second electrode 2 in a sheet form wound on the second electrode roll 73 at a predetermined interval when the second electrode 2 is unwound and supplied to form the second electrode 2 of a predetermined size, a second conveyor belt 75 that moves the second electrode 2 cut by the second cutter 74, and a second electrode supply head 76 that vacuum-adsorbs the second electrode 2 transferred by the second conveyor belt 75 and places it on the second electrode placement table 71.

[0056] Here, the second cutter 74 can cut the second electrode 2 in a sheet form so that a second electrode tab protrudes from the end when cutting.

[0057] Furthermore, the second electrode supply unit may include a second suction head 72 that vacuum-sucks the second electrode 2 placed on the second electrode placement 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 suction head 72 can stack the second electrode 2 placed on the second electrode placement table 71 on the stacking table 10.

[0058] Then, the second suction head 72 may include a vacuum suction port (not shown) that sucks 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] At this time, according to one embodiment of the present invention, the rotating part can rotate the stacking table 10 so that the stacking table 10 faces the first suction head 62 when stacking the first electrode 1, and can rotate the stacking table 10 so that the stacking table 10 faces the second suction head 72 when stacking the second electrode 2.

[0060] The fixing part 20 fixes the laminate S and includes at least one hole 21, 22 that exposes the laminate S. The fixing part 20 can be fixed by pressing in the stacking direction of the laminate S on one surface of the laminate S.

[0061] Referring to FIGS. 1 and 3, the fixing part 20 may include a first hole 21 that exposes the line where the separation film 4 is folded, and a second hole 22 that exposes the line orthogonal to the line where the separation film is folded.

[0062] The laminate S according to the present invention may include two long sides that are the side surfaces or ends where the separation film is folded, and two short sides that are the side surfaces or ends where the electrode tabs protrude and are orthogonal to the long sides.

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

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

[0065] A plurality of fixing portions 20 may be included. The fixing portion 20 can be extended in the length direction of the laminate S to fix the laminate S. And two fixing portions 20 may be provided as a pair.

[0066] Of the pair of fixing portions 20, one fixing portion 20 may be extended in the length direction of the laminate S from the third end portion s3, and the other fixing portion 20 may be extended in the length direction of the laminate S from the fourth end portion s4. And the pair of fixing portions 20 may be spaced apart.

[0067] Two pairs of fixing portions 20 may be included. One pair of fixing portions 20 may be positioned adjacent to the first end portion s1, and the other pair of fixing portions 20 may be positioned adjacent to the second end portion s2. Or, one end of one pair of fixing portions 20 may be positioned on the same line as the first end portion s1, and one end of the other pair of fixing portions 20 may be positioned on the same line as the second end portion s2.

[0068] The form of the first hole 21 is not limited as long as it can expose the line where the separation membrane is folded. For example, it may be provided in a square or rectangular form. The form of the second hole 22 is not limited as long as it can expose the line orthogonal to the line where the separation membrane is folded. For example, it may be provided in a circular form.

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

[0070] The photographing unit 30 may photograph the first hole 21 and the second hole 22 together with the stack table respectively, or photograph so as to include all of the first hole 21, the second hole 22, and the stack table. And the photographing unit 30 can photograph the first hole 21 and the second hole 22 every time the separation membrane 4 is laminated on one surface of a plurality of positive electrodes and negative electrodes, and confirm the alignment of the positive electrode, the negative electrode, and the separation membrane of each layer.

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

[0072] Alternatively, the determination unit 40 measures the distance between the third end s3 or the 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 the fourth end s4.

[0073] Alternatively, the determination unit 40 measures all of 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 electrode stack inspection device 100 of the secondary battery includes two pairs of fixing parts 20. The first pair of fixing parts 20 is located at a portion adjacent to the first end s1 and fixes the negative electrode and the separation membrane. The second pair of fixing parts 20 is located at a portion adjacent to the second end s2 and fixes the positive electrode and the separation membrane.

[0075] After the negative electrode stack, the separation membrane stack, and the folding, the first pair of fixing parts 20 fix the laminate S. The imaging unit 30 images the first hole 21 and the second hole 22 formed in the first pair of fixing parts 20. Then, the determination unit 40 receives the image captured by the imaging unit 30 and measures the distance between the first end s1 captured together with the first hole 21 on the captured image and the end of the stack table parallel to the first end s1. And the determination unit 40 measures the distance between the third end s3 captured with the second hole 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, the negative electrode, or the separation membrane 4 by comparing the measured distance between the separation membrane 4 and the end of the stack table with a preset reference value.

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

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

[0079] The determination part 40 can confirm the alignment of the positive electrode, the negative electrode, or the separation membrane 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 part 40 can determine that it is normal when 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 is less than or equal to the reference value, and can determine misalignment when 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.

[0080] Or, the determination part 40 can use the n-th x distance and the n-th yIf the distance is equal to or less than a preset reference value, it is normal. If it exceeds the reference value, it can be determined as misalignment. That is, the preset reference value is the distance between the first end portion s1 or the second end portion s2 and the end portion of the stack table, or the difference between the nth x distance and the (n + 1)th x distance, or the error value within the normal range between the nth y distance and the (n + 1)th y distance may be.

[0081] In one embodiment, when the reference value is the distance between the end portion of the positive electrode, the negative electrode, or the separator 4 and the end portion of the stack table, the reference value of the nth x distance may be 5 mm or less. Preferably, the reference value of the nth x distance may be 3 mm or less, and more preferably, 2 mm or less. And the reference value of the nth y distance may be 10 mm or less. Preferably, the reference value of the nth y distance is 6 mm or less, and more preferably, 4 mm or less.

[0082] When any one or more of the nth x distance and the nth y distance measured by the determination unit 40 exceeds the reference value, the determination unit 40 can determine that the alignment of the electrode and the separator is misaligned.

[0083] The secondary battery electrode stack 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 photographing unit 30, the stack table, and the like.

[0084] For example, the control unit can control the fixing and release of the laminate S by the fixing unit 20, and can control the photographing position of the photographing unit 30.

[0085] When the secondary battery electrode stack inspection apparatus 100 according to the present invention or the secondary battery electrode stack inspection apparatus 100 is included in the electrode assembly manufacturing apparatus, the electrode assembly manufacturing apparatus may further include an electrode realignment unit (not shown).

[0086] When it is determined by the determination unit 40 that the lamination of the electrodes is defective, the electrode rearrangement unit can rearrange the electrodes that have been determined to be defective. In one embodiment, the control unit can release the fixation of the laminate S of the fixing unit 20 and move the stack table to the electrode rearrangement unit. Alternatively, the control unit can move the electrode rearrangement unit to the stack table to laminate the electrodes again.

[0087] The method for inspecting the electrode lamination of a secondary battery includes a laminate manufacturing step S10 of supplying a plurality of positive electrodes and negative electrodes to a stack table, supplying a separator between the positive electrode and the negative electrode, and manufacturing a laminate, a laminate fixing step S20 of fixing the laminate in the lamination direction using a fixing unit including at least one hole exposing the laminate, and a photographing step S30 of photographing the laminate exposed through the hole.

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

[0089] The photographing step S30 can photograph the hole of the fixing unit and the stack table. At this time, the hole may include a first hole exposing the line where the separator is folded and a second hole exposing a line orthogonal to the line where the separator is folded.

[0090] The photographing step S30 can photograph the first hole and the stack table and the second hole and the stack table respectively, or can photograph them at once so that the first hole, the second hole, and the stack table are all included.

[0091] The method for inspecting the electrode lamination of a secondary battery further includes a determination step S40 of determining the presence or absence of lamination defects of the positive electrode, the negative electrode, and the separator based on the data photographed in the photographing step S30.

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

[0093] The determination step S40 is the nth distance, which is the distance between the first end or the second end of the separation membrane stacked in the nth layer and the end of the stack table. x Compare the nth distance with a preset reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane, or the nth distance, which is the distance between the third end or the fourth end of the separation membrane stacked in the nth layer and the end of the stack table. y Compare with the preset reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane.

[0094] The method for inspecting electrode lamination of a secondary battery can cite the description of the apparatus for inspecting electrode lamination of a secondary battery.

[0095] As described above with reference to the preferred embodiments of the present invention, those skilled in the art should understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the appended claims.

Example

[0096] [Comparative Example] The comparative example uses a conventional electrode lamination inspection apparatus and inspection method for secondary batteries. The fixing part included in the electrode lamination inspection apparatus for secondary batteries does not contain holes. And the electrode lamination inspection method for secondary batteries fixes the four corners of the laminate using four fixing parts after laminating the electrodes and the separator. Before photographing the lamination state of the electrodes with the photographing unit, the fixing of the fixing part is released and the laminate is photographed. The determination unit measures the nth x distance and the nth y distance, compares them with a reference value, and determines whether there is a lamination defect in the electrodes.

[0097] [Example] The example determines whether there is a lamination defect in the electrodes using the electrode lamination inspection apparatus and inspection method for secondary batteries according to the present invention.

[0098] Fig. 6 is a fitting line graph of the nth x distance of each electrode of the laminate measured in the comparative example and the nth x distance actually measured by cutting the cross-section of the laminate. Fig. 7 is a fitting line graph of the nth x distance of each electrode of the laminate measured in the example and the nth x distance actually measured by cutting the cross-section of the laminate. Fig. 8 is a fitting line graph of the nth y distance of each electrode of the laminate measured in the example and the nth y distance actually measured by cutting the cross-section of the laminate.

[0099] The nth x distance measurement was performed at two locations adjacent to the electrode tabs at the first end and the second end respectively. The nth x distance measurement positions are set as x1, x2, x3, and x4 in the order of the upper right, lower, upper left, and lower parts of the laminate shown in Figs. 6 and 7. And the nth y distance measurement is performed at two locations at the third end and the fourth end respectively, and is set as y1, y2, y3, and y4 in the order of the upper right, lower, upper left, and lower parts of the laminate shown in Fig. 8.

[0100] The fitting line graphs in Figs. 6 and 7 are the nth xThe distance was plotted on the x-axis, and the cross-section of the laminate was cut and the nth x distance was plotted on the y-axis. Then, a regression equation was calculated by performing a linear regression analysis using the above variables. The calculated regression equations were different for each position, and the regression equations were plotted on a graph for each position. And the R-squared value (R 2 ) indicating the reliability of the regression equation was also plotted on a graph for each position.

[0101] Referring to FIG. 6, it can be seen that in the comparative example, the distribution of the nth x distance with respect to the nth x distance measured by the determination unit spreads widely with respect to the fitting line. That is, it can be seen that the reliability of the fitting line of the comparative example, in other words, the R-squared value (R 2 ) of the comparative example is less than 60% and the reliability is low.

[0102] Referring to FIGS. 7 and 8, it can be seen that in the example, the R-squared value (R 2 ) is 64% or more and the reliability of the fitting line is high. That is, after fixing the laminate at the fixing portion, the nth x distance and the nth y distance measured through the holes are similar to the actually measured nth x distance and the nth y distance values, and it can be confirmed that they are reliable.

[0103]

Table 1

[0104]

Table 2

[0105] Tables 1 and 2 above are tables showing the nth x distance and the nth y distance measured using the electrode laminate inspection apparatus for a secondary battery according to the present invention, and the average, standard deviation σ, process capability Cp, and Cpk of the nth x distance and the nth y distance measured by cutting the cross-section of the laminate.

[0106] Cp (Capability of Process) means how dispersed the population measurement results are around the median value between the upper limit value and the lower limit value. In Tables 1 and 2, the upper limit value and the lower limit value of Cp are the highest value and the lowest value among the nth x distance and the nth y distance (x-axis). And the median value means the y-axis value (the number of measurements of the median value) of the central value (average) of the x-axis. When the Cp value exceeds 1, it means that the measurement results of the population are concentrated around the median value.

[0107] And Cpk (Capability of Process Katayori) means the degree of inclination of the median value. That is, it means the degree to which the median value inclines in the direction of the upper limit value or the lower limit value.

[0108] Referring to Tables 1 and 2, the nth x distance and the nth y distance measured (vision measurement) using the electrode laminate inspection apparatus for secondary batteries according to the present invention are found to be similar to the nth x distance and the nth y distance actually measured through the cross-section of the laminate.

[0109] And it can be seen that the standard deviation and the Cpk value are low, the Cp is high, and the nth x distance and the nth y distance are concentrated around the standard value.

Explanation of Signs

[0110] 100 ··· Electrode laminate inspection apparatus for secondary batteries 200 ··· Electrode assembly manufacturing apparatus 10 ··· Stack table 20 ··· Fixed part 21 ··· First hole 22 ··· Second hole 30 ··· Photographing part 40 ··· Judgment part 50 ··· Separator supply part 51 ··· Separation membrane heating part 52 ··· Separation membrane roll 61 ··· First electrode placement table 62 ··· First suction head 63 ··· First electrode roll 64 ··· First cutter 65 ··· First conveyor belt 66 ··· First electrode supply head 67 ··· First moving part 71 ··· Second electrode placement table 72 ··· Second suction head 73 ··· Second electrode roll 74 ··· Second cutter 75 ··· Second conveyor belt 76 ··· Second electrode supply head 77 ··· Second moving part 1 ··· First electrode 2 ··· Second electrode 4 ··· Separation membrane S ··· Laminate s1 ··· First end s2 ··· Second end s3 ··· Third end s4 ··· Fourth end

Claims

1. 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 part that fixes one surface of the laminate and includes at least one hole that exposes the laminate; and An imaging part that images the laminate exposed through the hole; An electrode laminate inspection device for a secondary battery, comprising:

2. The imaging part images each time a plurality of the positive electrodes and negative electrodes are laminated, respectively. The electrode laminate inspection device for a secondary battery according to Claim 1.

3. The separator includes a first end, a second end facing the first end, a third end and a fourth end connecting the first end and the second end, The fixing part 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. The electrode laminate inspection device for a secondary battery according to Claim 1.

4. The imaging part images the first hole, the second hole, and the stack table. The electrode laminate inspection device for a secondary battery according to Claim 3.

5. The electrode laminate inspection device for a secondary battery according to Claim 3, further comprising a determination part that analyzes the positions of the positive electrode, the negative electrode, and the separator based on data imaged by the imaging part, and determines misalignment of the positive electrode, the negative electrode, and the separator.

6. The determination part measures a distance between a first end or a second end of the separator exposed through the first hole and an end of the stack table parallel to the first end or the second end. The electrode laminate inspection device for a secondary battery according to Claim 5.

7. The determination unit compares an nth distance, which is a distance between a first end or a second end of the separation membrane laminated at the nth position and an end of the stack table, with a preset reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane. The electrode stack inspection apparatus for a secondary battery according to claim 6. ｘ The electrode stack inspection apparatus for a secondary battery according to claim 6, wherein the determination unit compares an nth distance, which is a distance between a first end or a second end of the separation membrane laminated at the nth position and an end of the stack table, with a preset reference value to determine misalignment of the negative electrode, the positive electrode, and the separation membrane.

8. The determination part measures a distance between a third end or a fourth end of the separator exposed through the second hole and an end of the stack table parallel to the third end or the fourth end. The electrode laminate inspection device for a secondary battery according to Claim 5.

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

10. A plurality of fixing parts are included, and two of them are positioned in a pair along the length direction of the laminate. The electrode laminate inspection device for a secondary battery according to any one of Claims 1 to 9.

11. Two pairs of the fixing parts are included, and the two pairs of fixing parts alternately fix the laminate. The electrode laminate inspection device for a secondary battery according to Claim 10.

12. A laminate manufacturing step of supplying a plurality of positive electrodes and negative electrodes to a stack table, supplying a separator between the positive electrode and the negative electrode, and manufacturing a laminate; A laminate fixing step of fixing the laminate in the laminating direction by using a fixing part including at least one hole exposing the laminate; and A photographing step of photographing the laminate exposed through the hole; A method for inspecting electrode lamination of a secondary battery, including the above.

13. The method for inspecting electrode lamination of a secondary battery according to claim 12, wherein in the laminate fixing step and the photographing step, the laminate is fixed each time the separator is supplied to one surface of the positive electrode and the negative electrode, and the hole of the fixing part and the stack table are photographed.

14. The separator includes a first end portion, a second end portion facing the first end portion, and third and fourth end portions connecting the first end portion and the second end portion. In the laminate fixing step, the fixing part includes a first hole exposing the first end portion or the second end portion and a second hole exposing the third end portion or the fourth end portion, according to the method for inspecting electrode lamination of a secondary battery according to claim 12.

15. The method for inspecting electrode lamination of a secondary battery according to claim 14, wherein the photographing step photographs the first hole, the second hole, and the stack table.

16. The method for inspecting electrode lamination of a secondary battery according to claim 14, further including a determination step of analyzing the positions of the positive electrode, the negative electrode, and the separator based on the photographed data to determine misalignment of the positive electrode, the negative electrode, and the separator.

17. In the determination step, the method for inspecting electrode lamination of a secondary battery according to claim 16 measures the distance between the first end portion or the second end portion of the separator exposed through the first hole and the end portion of the stack table parallel to the first end portion or the second end portion.

18. In the determination step, the method for inspecting electrode lamination of a secondary battery according to claim 17 compares the nth x distance, which is the distance between the first end portion or the second end portion of the nth laminated separator and the end portion of the stack table, with a preset reference value to determine misalignment of the negative electrode, the positive electrode, and the separator.

19. In the determination step, the method for inspecting electrode lamination of a secondary battery according to any one of claims 16 to 18 measures the distance between the third end portion or the fourth end portion of the separator exposed through the second hole and the end portion of the stack table parallel to the third end portion or the fourth end portion.

20. The determination step is the nth distance between the third end or the fourth end of the separation membrane laminated at the nth position and the end of the stack table. ｙ The method for inspecting electrode lamination of a secondary battery according to claim 19, wherein misalignment of the negative electrode, the positive electrode, and the separation membrane is determined by comparing the distance with a preset reference value.

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