Secondary battery electrode tab processing device and electrode tab processing method using the same

Abstract

The present invention relates to an electrode tab processing apparatus for a secondary battery and an electrode tab processing method using the same, and more particularly to an electrode tab processing apparatus for forming a connecting portion by cutting a predetermined region of an electrode tab extending toward one side of an electrode collector so that a metal foil can be connected to the electrode tab.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0141266, filed October 20, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrode tab processing apparatus for a secondary battery and an electrode tab processing method using the same, and more particularly to an electrode tab processing apparatus for a secondary battery capable of selectively cutting a certain region of an electrode tab and an electrode tab processing method using the same. [Background technology]

[0003] With technological development and increasing demand for mobile devices, rechargeable secondary batteries are being used as energy sources for various mobile devices. Secondary batteries are also attracting attention as energy sources for electric vehicles and hybrid electric vehicles, which are being proposed as alternatives to existing gasoline and diesel vehicles that use fossil fuels.

[0004] Depending on the shape of the battery case, secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch batteries in which the electrode assembly is housed in a pouch-shaped case made of an aluminum laminate sheet.

[0005] In particular, in the case of a pouch-type secondary battery, a number of positive and negative electrodes having a predetermined size are stacked in sequence with a separator interposed between them, and an electrode tab or a pair of electrode leads connected to the electrode tabs protrudes from one or both sides of the case to the outside.

[0006] Meanwhile, aluminum current collectors are commonly used as positive electrode current collectors on which the positive electrode active material is applied. However, as aluminum current collectors have been identified as a major cause of fires due to various reasons, research is being conducted to replace them with multi-layered current collectors, for example, current collectors with a structure in which a resin layer is sandwiched between two metal layers.

[0007] When using such a three-layered current collector, the metal layer is thin, so there is a large resistance in the event of a short circuit, allowing the flow of current to be quickly cut off, which is expected to improve safety.

[0008] Figure 1 is a partial schematic diagram of a secondary battery according to the prior art. As shown in Figure 1, the electrode assembly 10 has a structure in which a number of tabs 20 extend outward, electrode leads 30 are interposed between these tabs 20, and the tabs 20 are then fixed together by welding.

[0009] However, in the case of a three-layered current collector, since a resin layer is provided in the middle, it is difficult to join the electrode tab and the electrode lead using a commonly used welding method.

[0010] In this regard, the applicant has previously filed a patent application for an invention relating to a secondary battery electrode assembly and a battery cell including the same, in which the electrode tab and the electrode lead can be securely fixed by providing an incision line in the electrode tab, penetrating the metal foil in a zigzag pattern, and then welding the electrode lead together with the metal foil and the electrode tab.

[0011] However, there is a drawback in that a high level of skill is required from the operator in order to cut only a portion of the electrode tab and to penetrate the metal foil along the cutting line. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Korean Patent Publication No. 10-2022-0124358 [Patent Document 2] Korean Patent Publication No. 10-2023-0020177 [Patent Document 3] Korean Patent Publication No. 10-2023-0124641 Summary of the Invention [Problem to be solved by the invention]

[0013] In order to solve the above problems, an object of the present invention is to provide an electrode tab processing device for a secondary battery, which can process an electrode tab regardless of the skill level of an operator when connecting an electrode tab having a resin layer interposed between metal layers and a metal foil, and an electrode tab processing method using the same. [Means for solving the problem]

[0014] The electrode tab processing device according to the present invention, which solves the above-mentioned problems, is an electrode tab processing device for forming a connecting portion by cutting a certain area of ​​an electrode tab extending in one direction of an electrode current collector so that a metal foil can be connected to the electrode tab, and includes a lower jig (800) disposed on one side of the electrode tab and an upper jig (900) disposed on the other side of the electrode tab, and a pair of first lower flat portions (811) are disposed on the upper surface of the lower jig (800) along the longitudinal direction while being spaced apart from each other, and the pair of first lower flat portions (811) A lower protrusion (812) is provided between the upper jig (900) and a pair of first upper flat portions (911) are spaced apart from each other and positioned along the longitudinal direction on the underside of the upper jig (900), and an upper recess (912) is provided between the pair of first upper flat portions (911) to engage with the lower protrusion (812). When the electrode tab is pressed between the lower jig (800) and the upper jig (900), a connection portion through which the metal foil can pass is formed by a pair of cut lines spaced apart at a regular interval.

[0015] In addition, the electrode tab processing apparatus according to the present invention is characterized in that a lower recess (822) is further provided on the upper surface of the lower jig (800) along the longitudinal direction, and an upper protrusion (922) is further provided on the lower surface of the upper jig (900) along the longitudinal direction to engage with the lower recess (822).

[0016] In addition, in the electrode tab processing apparatus according to the present invention, the lower protrusion (812) is located at the center of the upper surface of the lower jig (800), and the lower recesses (822) consist of a pair located on both sides of the lower protrusion (812), and the upper recesses (912) are located at the center of the lower surface of the upper jig (900), and the upper protrusions (922) consist of a pair located on both sides of the upper recesses (912).

[0017] In addition, in the electrode tab processing device according to the present invention, the lower jig (800) includes a first lower body (810) having the lower protrusion (812) and a second lower body (820) in which the lower recess (822) is located, and the first lower body (810) and the second lower body (820) are separable structures.

[0018] In addition, in the electrode tab processing device according to the present invention, the upper jig (900) includes a first upper body (910) having the upper recess (912) and a second upper body (920) in which the upper protrusion (922) is located, and the first upper body (910) and the second upper body (920) are separable structures.

[0019] In addition, in the electrode tab processing apparatus according to the present invention, the lower jig (800) further comprises a first heating member (830).

[0020] In addition, in the electrode tab processing apparatus according to the present invention, the upper jig (900) further comprises a second heating member (930).

[0021] In addition, in the electrode tab processing apparatus according to the present invention, the cross sections of the lower protrusion (812) and the upper depression (912) in the width direction are semicircular or semielliptical.

[0022] In addition, in the electrode tab processing apparatus according to the present invention, the cross sections of the lower recessed portion (822) and the upper protruding portion (922) in the width direction are semicircular or semielliptical.

[0023] In the electrode tab processing apparatus according to the present invention, the electrode current collector has a multi-layer structure in which a resin layer is interposed between a pair of metal layers.

[0024] In addition, the method for processing an electrode tab using the electrode tab processing apparatus according to the present invention includes a first step of positioning the electrode tab between the lower jig (800) and the upper jig (900), and a second step of moving at least one of the lower jig (800) and the upper jig (900) to press the electrode tab.

[0025] In addition, the electrode tab processing method according to the present invention is characterized in that at least one of the lower jig (800) and the upper jig (900) is heated before or during the second step. [Effects of the Invention]

[0026] The secondary battery electrode tab processing apparatus and electrode tab processing method using the same according to the present invention include a lower jig having a lower protrusion on its upper surface and an upper jig having an upper recess on its lower surface that engages with the lower protrusion, and the electrode tab is positioned between the lower jig and the upper jig, and then pressed, thereby making it possible to consistently form an incision line at a fixed position.

[0027] Furthermore, according to the secondary battery electrode tab processing apparatus and electrode tab processing method using the same according to the present invention, the electrode tab is positioned between the lower jig and the upper jig and then pressed, so the quality of the processed electrode tab is consistent regardless of the skill level of the operator.

[0028] In addition, according to the secondary battery electrode tab processing apparatus and electrode tab processing method using the same according to the present invention, since the lower jig and the upper jig have a structure in which a number of unit members are connected, it is possible to replace only specific unit members, thereby reducing processing costs. [Brief explanation of the drawings]

[0029] [Figure 1]FIG. 1 is a partial schematic diagram of a secondary battery according to the prior art. [Figure 2] 1 is an exploded perspective view of a secondary battery electrode assembly according to a first embodiment of the present invention; [Figure 3] 1 is a cross-sectional view of a positive electrode of a secondary battery electrode assembly according to a first embodiment of the present invention. [Figure 4] 1 is a top view of a secondary battery electrode assembly according to a first embodiment of the present invention; [Figure 5] 1 is a bottom view of a secondary battery electrode assembly according to a first embodiment of the present invention; [Figure 6] 5 is an exploded perspective view showing an enlarged view of a portion A of the electrode assembly shown in FIG. 4. FIG. [Figure 7] FIG. 10 is an exploded perspective view of a secondary battery electrode assembly according to a second embodiment of the present invention. [Figure 8] FIG. 4 is a cross-sectional view of a negative electrode of a secondary battery electrode assembly according to a second embodiment of the present invention. [Figure 9] FIG. 6 is a top view of a secondary battery electrode assembly according to a second embodiment of the present invention. [Figure 10] 10 is a bottom view of a secondary battery electrode assembly according to a second embodiment of the present invention; FIG. [Figure 11] 10 is an exploded perspective view showing an enlarged view of part B of the electrode assembly shown in FIG. 9. FIG. [Figure 12] 1 is a perspective view of an electrode tab processing device according to a first embodiment of the present invention for processing an electrode tab of a secondary battery electrode assembly. [Figure 13] 13 is a cross-sectional view of the electrode tab processing device shown in FIG. 12 taken along the line AA. [Figure 14] 13 is a perspective view of the upper jig of the electrode tab processing device shown in FIG. 12 as seen from below. FIG. [Figure 15] 10 is a perspective view of an electrode tab processing device according to a second embodiment of the present invention for processing an electrode tab of a secondary battery electrode assembly. FIG. [Figure 16] 3 is a perspective view illustrating a method for processing an electrode tab of a secondary battery electrode assembly using the electrode tab processing device according to the first embodiment; FIG. [Figure 17]3 is an enlarged perspective view of an electrode tab of a secondary battery electrode assembly processed by the electrode tab processing device according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] In this application, the terms "comprises," "has," "has," and "comprises" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0032] Hereinafter, a secondary battery electrode tab processing apparatus and an electrode tab processing method using the same according to the present invention will be described with reference to the accompanying drawings.

[0033] First, a secondary battery electrode assembly, which is an object of the electrode tab processing device according to the present invention, will be described.

[0034] FIG. 2 is an exploded perspective view of an electrode assembly for a secondary battery according to a first embodiment of the present invention, and FIG. 3 is a cross-sectional view of a positive electrode of the electrode assembly for a secondary battery according to the first embodiment of the present invention.

[0035] As shown in FIGS. 2 and 3, the secondary battery electrode assembly according to the present invention has a structure in which one or more positive electrodes 100, one or more negative electrodes 200, and one or more separators 300 are stacked.

[0036] In detail, the separator 300 may be located between the positive electrode 100 and the negative electrode 200, on the uppermost negative electrode 200, and below the lowermost negative electrode 200, but is not necessarily limited thereto.

[0037] In addition, a positive electrode lead 400 is electrically connected to the positive electrode 100, and a negative electrode lead 500 is electrically connected to the negative electrode 200. In particular, a first metal foil 600 is interposed between the positive electrode 100 and the positive electrode lead 400, which will be described in detail later.

[0038] First, the positive electrode 100 may be composed of a positive electrode current collector 110 and a positive electrode tab 120. The positive electrode current collector 110 according to the first preferred embodiment of the present invention has a three-layer structure in which a first resin layer 112 is interposed between a pair of aluminum layers 111.

[0039] Here, the thickness of the aluminum layer is approximately 0.5 to 2 μm, and the first resin layer is made of polyethylene terephthalate (PET) material and has a thickness of approximately 5 to 10 μm, but is not necessarily limited to this.

[0040] In addition, instead of aluminum, stainless steel, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used as long as it does not cause chemical changes in the battery and has high conductivity. In addition, to increase the adhesive strength of the positive electrode active material, the surface may be formed with fine irregularities, or various forms such as a film, sheet, foil, net, porous material, foam, or nonwoven fabric may be used.

[0041] A positive electrode active material layer 113 is provided on each of the upper and lower surfaces exposed to the outside of the pair of aluminum layers 111 .

[0042] Positive electrode active materials include layered compounds such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or compounds substituted with higher transition metals;1+x Mn 2-x Lithium manganese oxides such as LiMnO4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); 2-x M x Lithium manganese composite oxides expressed as Li2Mn3MO8 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1); LiMn2O4, in which part of the Li in the chemical formula is replaced by an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, LiNi x Mn 2-x O4 (0.01≦x≦0.6) can be used.

[0043] In addition, a conductive material and a binder can be mixed with the positive electrode active material, and a filler can also be added if necessary. These conductive materials, binders, and fillers correspond to known substances, so detailed description will be omitted.

[0044] Meanwhile, a blank portion (not shown) of the positive electrode current collector 110 where the positive electrode active material layer is not formed is punched out into a predetermined shape to form a positive electrode tab 120 .

[0045] The negative electrode 200 can be composed of a negative electrode current collector 210 and a negative electrode tab 220. The negative electrode current collector 210 is generally manufactured to have a thickness of 3 to 500 μm. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes to the battery. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, or a surface-treated copper or stainless steel with carbon, nickel, titanium, silver, etc., or an aluminum cadmium alloy can be used.

[0046] Also, fine concavities and convexities can be formed on the surface to strengthen the binding force of the negative electrode active material, and various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven bodies, etc. can be used.

[0047] A negative electrode active material layer is provided on the upper and lower surfaces of the negative electrode current collector 210. As the negative electrode active material, for example, carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, elements of Group 1, Group 2, Group 3 of the periodic table, halogen; 0 < x≦1; 1≦y≦3; 1≦z≦8), etc. metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; Si-based materials that are Si, SiO, SiO2 alone or a mixture of these can be used, but are not limited thereto.

[0048] Of course, a conductive material and a binder can be additionally mixed into the negative electrode active material to form a negative electrode active material layer. Since these conductive materials and binders correspond to known substances, detailed descriptions are omitted.

[0049] Meanwhile, a blank portion (not shown) of the negative electrode current collector 210 where the negative electrode active material layer is not formed is punched out into a predetermined shape to form a negative electrode tab 220 .

[0050] The separator 300 prevents short circuits between the cathode 100 and anode 200 and allows only the movement of lithium ions. The material of the separator is preferably any one selected from the group consisting of polyethylene, polypropylene, a polyethylene / polypropylene double layer, a polyethylene / polypropylene / polyethylene triple layer, a polypropylene / polyethylene / polypropylene triple layer, and organic fiber filter paper, but is not limited thereto.

[0051] FIG. 4 is a top view of a secondary battery electrode assembly according to a first embodiment of the present invention, FIG. 5 is a bottom view of a secondary battery electrode assembly according to the first embodiment of the present invention, and FIG. 6 is an exploded perspective view of an enlarged portion A of the electrode assembly shown in FIG.

[0052] The electrical connection structure between the positive electrode tab 120 and the positive electrode lead 400 will be described with reference to FIGS.

[0053] Generally, positive electrode tabs are made of metal only and can be connected to positive electrode leads by ultrasonic welding, etc. However, as described above, the positive electrode current collector and positive electrode tab according to the first embodiment of the present invention have a structure in which a first resin layer is interposed between a pair of aluminum layers. That is, due to the first resin layer that constitutes each positive electrode tab, it is difficult to firmly fasten multiple positive electrode tabs and the positive electrode leads to each other using ultrasonic welding.

[0054] Therefore, in the first embodiment of the present invention, the first connecting portion 122 is formed together with the first incision line 121 along the entire length direction (x-axis direction) of the positive electrode tab 120, while the first metal foil 600 is arranged to pass through the first incision line 121.

[0055] More specifically, two first incision lines 121 are arranged parallel to each other and spaced apart at a regular interval along the entire length (x-axis direction) of the positive electrode tab 120, and these first incision lines 121 form the first connecting portion 122.

[0056] Here, it is preferable that the first connecting portion 122 bulges upward so that the first metal foil 600 can easily pass through the first incision line 121. An apparatus and method for processing into such a structure will be described later.

[0057] Meanwhile, both side ends of the first cutting line 121 are preferably positioned inside the positive electrode tab 120 so that the first metal foil 600 passing through the first cutting line 121 does not come off.

[0058] After the first metal foil 600 passes through one of the two first incision lines 121, it then passes through the other first incision line 121, so that the first metal foil 600 is exposed at both side edges in the width direction (z-axis direction) of the positive electrode tab 120, while the first connecting portion 122 is located in the center (see Figure 4).

[0059] On the other hand, on the back surface of the positive electrode tab 120, the first metal foil 600 is not exposed at both side edges in the width direction (z-axis direction), but the middle portion is exposed (see FIG. 5).

[0060] As a result, since the first metal foil 600 has a ribbon shape passing through the two first incision lines 121 in a zigzag pattern, the first metal foil 600 allows the multiple positive electrode tabs 120 to form a single tab bundle.

[0061] Then, the positive electrode lead 400 is brought into close contact with a part of the positive electrode tab 120 and a part of the first metal foil 600, and then fixed thereto by ultrasonic welding.

[0062] Here, it is preferable that the positive electrode lead 400 faces the exposed surface of the first metal foil 600 at both side edges in the width direction (z-axis direction) of the positive electrode tab 120. This is because bonding and fixing the both side edges in the width direction (z-axis direction) of the positive electrode tab 120 to the positive electrode lead 400 is more effective in suppressing loose movement in the width direction (z-axis direction).

[0063] Of course, it goes without saying that the first metal foil 600 contributes to electrically connecting the positive electrode tab 120 and the positive electrode lead 400 .

[0064] On the other hand, the first metal foil 600 is preferably made of the same aluminum material as the aluminum layer 111, but may be made of any material that can perform the same function.

[0065] Furthermore, it is preferable that the length of the first metal foil 600 does not exceed the width of the positive electrode tab 120 , and the width of the first metal foil 600 is preferably slightly shorter than the length of the first incision line 121 .

[0066] The positive electrode lead 400 is preferably made of aluminum, but is not necessarily limited to this.

[0067] FIG. 7 is an exploded perspective view of an electrode assembly for a secondary battery according to a second embodiment of the present invention, and FIG. 8 is a cross-sectional view of a negative electrode of the electrode assembly for a secondary battery according to the second embodiment of the present invention.

[0068] The secondary battery electrode assembly according to the second embodiment of the present invention has a structure in which one or more positive electrodes 100, one or more negative electrodes 200, and one or more separators 300 are stacked, similar to the first embodiment.

[0069] In the second embodiment, the negative electrode 200 has a three-layer structure, and differs from the first embodiment in that a second metal foil 700 is interposed between the negative electrode 200 and the negative electrode lead 500. Therefore, a redundant explanation will be omitted and only the different configurations will be explained.

[0070] The negative electrode 200 may be composed of a negative electrode current collector 210 and a negative electrode tab 220. The negative electrode current collector 210 according to the second preferred embodiment of the present invention has a three-layer structure in which a second resin layer 212 is interposed between a pair of copper layers 211.

[0071] Here, the copper layer has a thickness of approximately 0.5 to 2.0 μm, and the second resin layer is made of polyethylene terephthalate (PET) and has a thickness of approximately 3 to 10 μm, although the thickness is not necessarily limited to this.

[0072] Of course, any material that has high conductivity and does not cause chemical changes in the battery, such as stainless steel, can be used instead of copper.

[0073] The negative electrode active material layers 213 are provided on the upper and lower surfaces exposed to the outside of the pair of copper layers 211. These negative electrode active materials have been described above, so a detailed description will be omitted.

[0074] FIG. 9 is a top view of a secondary battery electrode assembly according to a second embodiment of the present invention, FIG. 10 is a bottom view of a secondary battery electrode assembly according to the second embodiment of the present invention, and FIG. 11 is an exploded perspective view enlarging part B of the electrode assembly shown in FIG. 9.

[0075] 7 to 11, the electrical connection structure between the negative electrode tab 220 and the negative electrode lead 500 will be described.

[0076] Generally, negative electrode tabs are made of metal only and can be connected to negative electrode leads by ultrasonic welding, etc. However, as described above, the negative electrode current collector and negative electrode tab according to the second embodiment of the present invention have a structure in which a second resin layer is interposed between a pair of copper layers. That is, due to the second resin layer constituting each negative electrode tab, it is difficult to firmly secure multiple negative electrode tabs to each other using ultrasonic welding, and thus to firmly secure the negative electrode tabs and negative electrode leads to each other.

[0077] Therefore, in the second embodiment of the present invention, the second connecting portion 222 is formed together with the second incision line 221 along the entire length direction (x-axis direction) of the negative electrode tab 220, while the second metal foil 700 is arranged to pass through the second incision line 221.

[0078] More specifically, two second incision lines 221 are arranged parallel to each other and spaced apart at a regular interval along the entire length (x-axis direction) of the negative electrode tab 220, and these second incision lines 221 form the second connection portion 222.

[0079] Here, it is preferable that the second connecting portion 222 bulges slightly upward so that the second metal foil 700 can easily pass through the second incision line 221. An apparatus and method for processing such a structure will be described later.

[0080] Meanwhile, both side ends of the second cutting line 221 are preferably positioned inside the negative electrode tab 220 so that the second metal foil 700 passing through the second cutting line 221 does not come off.

[0081] After the second metal foil 700 passes through one of the two second incision lines 221, it then passes through the other second incision line 221, so that the second metal foil 700 is exposed at both side edges in the width direction (z-axis direction) of the negative electrode tab 220, while the second connecting portion 222 is located in the center (see Figure 9).

[0082] On the other hand, the second metal foil 700 is not exposed at both side edges in the width direction (z-axis direction) on the back surface of the negative electrode tab 220, but the middle portion is exposed (see FIG. 10).

[0083] As a result, since the second metal foil 700 has a ribbon shape passing through the two second incision lines 221 in a zigzag pattern, the negative electrode tabs 220 form a single tab bundle by the second metal foil 700 .

[0084] The negative electrode lead 500 is then brought into close contact with a portion of the negative electrode tab 220 and a portion of the second metal foil 700, and then fixed thereto by ultrasonic welding.

[0085] Here, it is preferable that the negative electrode lead 500 faces the surface where the second metal foil 700 is exposed at both side edges in the width direction (z-axis direction) of the negative electrode tab 220. This is because bonding and fixing the both side edges in the width direction (z-axis direction) of the negative electrode tab 220 to the negative electrode lead 500 is more effective in suppressing loose movement in the width direction (z-axis direction).

[0086] Of course, the second metal foil 700 contributes to electrically connecting the negative electrode tab 220 and the negative electrode lead 500 .

[0087] On the other hand, the second metal foil 700 is preferably made of copper, nickel-coated copper, or a nickel-copper alloy, which is the same as or similar to the copper layer 211, but may be changed as long as it can perform the same function.

[0088] Furthermore, it is preferable that the length of the second metal foil 700 does not exceed the width of the negative electrode tab 220 , and the width of the second metal foil 700 is preferably slightly shorter than the length of the second incision line 221 .

[0089] The negative electrode lead 500 is made of nickel, but is not necessarily limited to this material.

[0090] Although not shown in the drawings, a secondary battery electrode assembly may be a combination of the first and second embodiments. For example, the positive electrode has a three-layer structure in which a first resin layer is sandwiched between a pair of aluminum layers, while the negative electrode has a three-layer structure in which a second resin layer is sandwiched between a pair of copper layers, and a first metal foil and a second metal foil are sandwiched between the positive electrode tab and the positive electrode lead, and between the negative electrode tab and the negative electrode lead, respectively.

[0091] Next, an electrode tab processing device for processing positive electrode tabs and negative electrode tabs to provide incision lines and connecting portions on the above-mentioned tabs, in other words, a first incision line and a first connecting portion on the positive electrode tab, and a second incision line and a second connecting portion on the negative electrode tab, will be described.

[0092] FIG. 12 is a perspective view of an electrode tab processing device according to a first embodiment of the present invention for processing electrode tabs of a secondary battery electrode assembly, FIG. 13 is a cross-sectional view of the electrode tab processing device shown in FIG. 12 taken along the line AA, and FIG. 14 is a perspective view of an upper jig of the electrode tab processing device shown in FIG. 12 as viewed from below.

[0093] 12 to 14, the electrode tab processing device according to the present invention includes a lower jig 800 and an upper jig 900 each having a rectangular hexahedral shape.

[0094] One side of the electrode tab to be processed is located on the top surface of the lower jig 800, and the bottom surface of the upper jig 900 is located on the other side of the electrode tab, but the positions of the lower jig 800 and the upper jig 900 may be reversed.

[0095] First, the lower jig 800 will be described in detail. The lower jig 800 may include a first lower body 810, a second lower body 820, and a first heating member 830.

[0096] A pair of first lower flat portions 811 are spaced apart along the longitudinal direction (x-axis direction) on the upper surface of the first lower body 810, and a lower protrusion 812 is provided between the pair of first lower flat portions 811. The first lower flat portion 811 and the lower protrusion 812 are configured to form the incision line and connection portion of the electrode tab.

[0097] Here, the cross section (xy plane) of the lower protrusion 812 in the width direction is preferably semicircular or semielliptical.

[0098] The second lower body 820 is composed of a pair of second lower flat portions 821, one on each side of the first lower body 810, and a pair of second lower flat portions 821 are spaced apart along the longitudinal direction (x-axis direction) on the upper surface, and a lower recess 822 may be provided between the pair of second lower flat portions 821.

[0099] Here, the cross section (xy plane) of the lower recess 822 in the width direction is preferably semicircular or semielliptical.

[0100] The first lower body 810 and the second lower body 820 are preferably configured to be separable so that only a specific lower body can be replaced as needed. For example, the first lower body 810 and the second lower body 820 can be fixed using bolts and nuts (not shown) that pass through them, or can be separated and then replaced, but are not limited to bolts and nuts as long as they can be fixed and separated.

[0101] The first heating member 830 is disposed in a shape penetrating the first lower body 810 and the second lower body 820, and is configured to heat the electrode tabs to a certain temperature when forming the incision lines and connection parts of the electrode tabs.

[0102] As mentioned above, it is advantageous for the connecting portion to protrude slightly upward to facilitate fastening of the metal foil, and therefore it is preferable to process the electrode tab while heating it to a certain temperature so that it can be slightly stretched.

[0103] In the drawings, the first heating member 830 is shown as being disposed so as to penetrate the first lower body 810 and the second lower body 820, but as long as the first lower body 810 and the second lower body 820 can be heated, the first heating member 830 does not necessarily have to be disposed in a penetrating shape.

[0104] Next, the upper jig 900 will be described in detail. The upper jig 900 may include a first upper body 910 , a second upper body 920 , and a second heating member 930 .

[0105] A pair of first upper flat portions 911 are spaced apart from each other along the longitudinal direction (x-axis direction) on the underside of the first upper body 910, and an upper recess 912 is provided between the pair of first upper flat portions 911 to engage with the lower protrusion 812 of the first lower body 810. Preferably, the cross section of the upper recess 912 in the width direction (xy plane) is semicircular or semielliptical, like the lower protrusion 812.

[0106] The second upper body 920 is composed of a pair of second upper flat portions 921, one on each side of the first upper body 910, and a pair of second upper flat portions 921 are positioned at a distance from each other along the longitudinal direction (x-axis direction) on the underside, and it is preferable that an upper protrusion 922 is provided between the pair of second upper flat portions 921 along the longitudinal direction (x-axis direction) so as to engage with the lower recessed portion 822 of the second lower body 820 described above.

[0107] Here, it is preferable that the cross section (xy plane) of the upper protrusion 922 in the width direction is semicircular or semielliptical, the same as the cross section of the lower depression 822 in the width direction.

[0108] The first upper body 910 and the second upper body 920 are preferably configured to be separable so that only a specific upper body can be replaced as needed. For example, the first upper body 910 and the second upper body 920 can be fixed or separated using bolts and nuts (not shown) that pass through the first upper body 910 and the second upper body 920, and then replaced. However, the first upper body 910 and the second upper body 920 are not limited to bolts and nuts as long as they can be fixed and separated.

[0109] The second heating member 930 is disposed in a shape penetrating the first upper body 910 and the second upper body 920, and is configured to heat the electrode tabs to a certain temperature when forming the incision lines and connection parts of the electrode tabs.

[0110] As mentioned above, it is advantageous for the connecting portion to protrude upward to facilitate fastening of the metal foil, and therefore it is preferable to process the electrode tab while heating it to a certain temperature so that it can be slightly stretched.

[0111] Although the drawings show the second heating member 930 as being arranged to penetrate the first upper body 910 and the second upper body 920, it is not essential that the second heating member 930 is arranged in a penetrating shape as long as it can heat the first upper body 910 and the second upper body 920.

[0112] 15 is a perspective view of an electrode tab processing apparatus according to a second embodiment of the present invention for processing electrode tabs of a secondary battery electrode assembly. The electrode tab processing apparatus according to the second embodiment is similar to the electrode tab processing apparatus according to the first embodiment described above, except for the configuration of the second lower body and the second upper body.

[0113] In the electrode tab processing apparatus according to the second embodiment, the upper surface of the second lower body 820 is flat, and the lower surface of the corresponding second upper body 920 is also flat.

[0114] Next, a method for processing an electrode tab using the electrode tab processing device of the first embodiment will be described.

[0115] FIG. 16 is a perspective view illustrating a method for processing electrode tabs of a secondary battery electrode assembly using the electrode tab processing device according to the first embodiment, and FIG. 17 is an enlarged perspective view of an electrode tab of a secondary battery electrode assembly processed by the electrode tab processing device according to the first embodiment.

[0116] 12, 16 and 17, the electrode tab processing method according to the present invention includes a first step of positioning the electrode tab between a lower jig 800 and an upper jig 900, and a second step of moving at least one of the lower jig 800 and the upper jig 900 to press the electrode tab.

[0117] The first step is to position the lower jig 800 on the lower surface of the positive electrode tab 120 and the upper jig 900 on the upper surface. Here, the first lower body 810 and the first upper body 910 must be positioned so as to overlap the portions where the first incision line 121 and the first connecting portion 122 are to be formed.

[0118] The second step is to press the positive electrode tab 120 by moving the lower jig 800 upward or the upper jig 900 downward, or by simultaneously moving them upward and downward.

[0119] When the lower jig 800 and the upper jig 900 are engaged with each other, the first connecting portion 122 is processed into a shape that bulges upward slightly so that the first metal foil can easily pass through the first incision line 121 .

[0120] In detail, both sides of the lower protrusion 812 of the first lower body 810 and the inner surfaces of the pair of upper protrusions 922 of the second upper body 920 act as block-shaped cutters, and the first incision line 121 is formed at the position where they intersect with each other.

[0121] In addition, the first connecting portion 122, which overlaps with the lower protrusion 812 of the first lower body 810, has an upwardly bulging shape similar to the outer shape of the lower protrusion 812. As a result, a gap is formed in the first connecting portion 122 around the first incision line 121 so that the first metal foil can easily pass through the first incision line 121.

[0122] Meanwhile, it is more preferable to heat at least one of the lower jig 800 and the upper jig 900 before or during the second stage.

[0123] For example, the electrode tabs may be heated for a certain period of time in a state where the upper surface of the lower jig 800 is in close contact with the lower surface of the electrode tab, or in a state where the upper surface of the lower jig 800 is in close contact with the lower surface of the electrode tab and the lower surface of the upper jig 900 is in close contact with the upper surface of the electrode tab, and then the second step may be performed.

[0124] This is because it is advantageous to process the first connecting portion 122 into a slightly bulging shape by providing a condition that allows the electrode tab to be stretched.

[0125] Meanwhile, although only the method for processing a positive electrode tab using the electrode tab processing device according to the first embodiment has been described, it is obvious that a negative electrode tab can be processed using the same process, and that both a positive electrode tab and a negative electrode tab can be processed using the electrode tab processing device according to the second embodiment.

[0126] Although specific portions of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific techniques are merely preferred embodiments and do not limit the scope of the present invention. It is possible to make various changes and modifications within the scope of the present invention and the technical ideas thereof, and it goes without saying that such changes and modifications are also within the scope of the appended claims. [Explanation of symbols]

[0127] 100 positive electrode 110 Positive electrode current collector 111 Aluminum layer 112 1st resin layer 113 Cathode active material layer 120 Positive electrode tab 121 First incision line 122 1st connection part 200 negative electrode 210 Negative electrode current collector 211 Copper layer 212 2nd resin layer 213 Negative electrode active material layer 220 Negative electrode tab 221 Second incision line 222 2nd connection part 300 Separation membrane 400 Positive lead 500 Negative lead 600 First Metal Foil 700 Second metal foil 800 Lower Jig 810 First Lower Fuselage 811 1st lower flat part 812 Lower ridge 820 Second Lower Fuselage 821 2nd lower flat part 822 Lower depression 830 First heating element 900 Upper Jig 910 First upper fuselage 911 1st upper flat part 912 Upper depression 920 2nd upper fuselage 921 2nd upper flat part 922 Upper ridge 930 Second heating element

Claims

1. An electrode tab processing device for forming a connecting portion by cutting a predetermined region of an electrode tab extending in one direction of an electrode current collector so that a metal foil can be connected to the electrode tab, a lower jig disposed on one side of the electrode tab; and an upper jig disposed on the other side of the electrode tab, a pair of first lower flat portions spaced apart from each other are positioned along a longitudinal direction on an upper surface of the lower jig, and a lower protrusion is provided between the pair of first lower flat portions; a pair of first upper flat portions spaced apart from each other are positioned along a longitudinal direction on a lower surface of the upper jig, and an upper recess is provided between the pair of first upper flat portions to engage with the lower protrusion; When the electrode tab is pressed while positioned between the lower jig and the upper jig, a connection portion through which the metal foil can pass is formed by a pair of cut lines spaced apart at a regular interval.

2. 2. The electrode tab processing apparatus of claim 1, wherein a lower recess is further provided on an upper surface of the lower jig along a longitudinal direction, and an upper protrusion is further provided on a lower surface of the upper jig along a longitudinal direction to engage with the lower recess.

3. the lower protrusion is located at the center of the upper surface of the lower jig, and the lower depressions are a pair of depressions located on both sides of the lower protrusion, 3. The electrode tab processing apparatus according to claim 2, wherein the upper recess is located at the center of the lower surface of the upper jig, and the upper protrusions are a pair of upper recesses located on both sides of the upper recess.

4. 4. The electrode tab processing apparatus of claim 3, wherein the lower jig includes a first lower body having the lower protrusion and a second lower body in which the lower recess is located, and the first lower body and the second lower body have separable structures.

5. 4. The electrode tab processing apparatus of claim 3, wherein the upper jig includes a first upper body having the upper recessed portion and a second upper body in which the upper protrusion portion is located, and the first upper body and the second upper body have separable structures.

6. The electrode tab processing apparatus according to claim 3 , wherein the lower jig further comprises a first heating member.

7. The electrode tab processing apparatus according to claim 3 , wherein the upper jig further comprises a second heating member.

8. 4. The electrode tab processing apparatus according to claim 3, wherein the lower protrusion and the upper depression have a semicircular or semielliptical cross section in the width direction.

9. 4. The electrode tab processing apparatus according to claim 3, wherein the cross sections of the lower recessed portion and the upper protruding portion in the width direction are semicircular or semielliptical.

10. 2. The electrode tab processing device according to claim 1, wherein the electrode current collector has a multi-layer structure in which a resin layer is interposed between a pair of metal layers.

11. An electrode tab processing method for processing an electrode tab using the electrode tab processing device according to any one of claims 1 to 10, comprising: a first step of positioning the electrode tab between the lower jig and the upper jig; a second step of moving at least one of the lower jig and the upper jig to press the electrode tab.

12. The method of claim 11 , further comprising heating at least one of the lower jig and the upper jig before or during the second step.

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