Electrode tab processing apparatus for secondary battery and electrode tab processing method using 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. More specifically, the present invention relates to an electrode tab processing apparatus in which, when an electrode tab is pressed in a state of being positioned between a lower jig and an upper jig, a connection portion through which a metal foil can extend is formed by a pair of cutting lines spaced apart from each other by a predetermined distance, therefore, the metal foil can be connected to an electrode tab extending in the direction of one side of the electrode current collector.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 2023-0141266, filed on October 20, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[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 predetermined area of each electrode tab in an electrode tab and an electrode tab processing method using the same. Background Art

[0003] With the technological development of mobile devices and the increase in their demand, secondary batteries capable of charging and discharging have been used as an energy source for various mobile devices. Secondary batteries have also attracted attention as an energy source for electric vehicles and hybrid electric vehicles, which exist as alternatives to existing gasoline vehicles and diesel vehicles that use fossil fuels.

[0004] According to the shape of the battery case, secondary batteries are classified into: cylindrical batteries having an electrode assembly mounted in a cylindrical metal can; prismatic batteries having an electrode assembly mounted in a prismatic metal can; and pouch-shaped batteries having an electrode assembly mounted in a pouch-shaped case made of an aluminum laminate.

[0005] In particular, in the case of pouch-shaped secondary batteries, a plurality of positive electrodes each having a predetermined size and a plurality of negative electrodes each having a predetermined size are sequentially stacked with a separator interposed therebetween, and electrode tabs or a pair of electrode leads connected to the electrode tabs protrude outward from one side or opposite sides of the case.

[0006] Meanwhile, an aluminum current collector is generally used as a positive current collector to which a positive electrode active material is applied. However, due to various reasons, the aluminum current collector has been pointed out as a main ignition source, and thus research is being conducted to replace the aluminum current collector with a multi-layer current collector, such as a current collector having a structure in which a resin layer is interposed between two metal layers.

[0007] When using such a three-layer current collector, it is envisioned that safety can be improved because a thin metal layer has a large resistance in the case of a short circuit and can quickly cut off the current.

[0008] Figure 1 is a partial schematic view of a conventional secondary battery. As Figure 1 shown therein, the electrode assembly 10 has a structure in which a plurality of tabs 20 extend outward, and electrode leads 30 are interposed between the tabs 20 and are fixed to the tabs 20 by welding.

[0009] However, in the case of a three-layer current collector, since a resin layer is provided in the middle, it is difficult to connect the electrode tab to the electrode lead by a conventional welding method.

[0010] In this regard, the applicant has proposed a secondary battery electrode assembly and a battery cell including the secondary battery electrode assembly. The secondary battery electrode assembly is configured such that a cutting line is provided in the electrode tab, the metal foil extends through the cutting line in a zigzag manner, and the electrode lead is welded to the metal foil and the electrode tab, whereby the electrode tab can be firmly fixed to the electrode lead.

[0011] However, there are the following disadvantages: skills of workers are required to cut only a part of the electrode tab and to make the metal foil extend through the cutting line.

[0012] (Prior art document)

[0013] (Patent Document 1) Korean Patent Application Publication No. 2022-0124358

[0014] (Patent Document 2) Korean Patent Application Publication No. 2023-0020177

[0015] (Patent Document 3) Korean Patent Application No. 2023-0124641 Summary of the Invention

[0016] Technical Problem

[0017] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrode tab processing apparatus for a secondary battery and an electrode tab processing method using the electrode tab processing apparatus, which can process an electrode tab when connecting an electrode tab having a resin layer interposed between metal layers and a metal foil to each other, regardless of the skill level of workers.

[0018] Technical Solution

[0019] The electrode tab processing apparatus according to the present invention is used to achieve the above object. The electrode tab processing apparatus is configured to form a connection portion by cutting a predetermined area of each electrode tab in the electrode current collector that extends in one direction, such that a metal foil can be connected to the electrode tab. The electrode tab processing apparatus includes a lower jig 800 positioned on one surface of each electrode tab in the electrode tab, and an upper jig 900 positioned on the other surface of each electrode tab in the electrode tab. Among them, a pair of first lower flat portions 811 are positioned on the upper surface of the lower jig 800 to be spaced apart from each other in the longitudinal direction, and a lower ridge portion 812 is provided between the pair of first lower flat portions 811. A pair of first upper flat portions 911 are positioned on the lower surface of the upper jig 900 to be spaced apart from each other in the longitudinal direction, and an upper concave portion 912 configured to engage with the lower ridge portion 812 is provided between the pair of first upper flat portions 911. And when the electrode tab is pressed in a state located between the lower jig 800 and the upper jig 900, a connection portion through which the metal foil can extend is formed by means of a pair of cutting lines spaced apart from each other by a predetermined distance.

[0020] In addition, in the electrode tab processing apparatus according to the present invention, the lower jig 800 may further be provided with a lower concave portion 822 along the longitudinal direction in its upper surface, and the upper jig 900 may further be provided with an upper ridge portion 922 along the longitudinal direction in its lower surface configured to engage with the lower concave portion 822.

[0021] In addition, in the electrode tab processing apparatus according to the present invention, the lower ridge portion 812 may be located in the middle of the upper surface of the lower jig 800, the lower concave portions 822 may be provided in pairs on both sides of the lower ridge portion 812, the upper concave portion 912 may be located in the middle of the lower surface of the upper jig 900, and the upper ridge portions 922 may be provided in pairs on both sides of the upper concave portion 912.

[0022] In addition, in the electrode tab processing apparatus according to the present invention, the lower jig 800 may include a first lower body 810 having the lower ridge portion 812 and a second lower body 820 in which the lower concave portion 822 is located, and the first lower body 810 and the second lower body 820 can be separated from each other.

[0023] In addition, in the electrode tab processing apparatus according to the present invention, the upper jig 900 may include a first upper body 910 having the upper concave portion 912 and a second upper body 920 on which the upper ridge portion 922 is located, and the first upper body 910 and the second upper body 920 can be separated from each other.

[0024] In addition, in the electrode tab processing apparatus according to the present invention, the lower jig 800 may further be provided with a first heating member 830.

[0025] In addition, in the electrode tab processing apparatus according to the present invention, the upper jig 900 may further be provided with a second heating member 930.

[0026] In addition, in the electrode tab processing apparatus according to the present invention, a transverse cross-section of each of the lower ridge portion 812 and the upper concave portion 912 may be semicircular or semi-elliptical.

[0027] In addition, in the electrode tab processing apparatus according to the present invention, a transverse cross-section of each of the lower concave portion 822 and the upper ridge portion 922 may be semicircular or semi-elliptical.

[0028] In addition, in the electrode tab processing apparatus according to the present invention, the electrode current collector may have a multi-layer structure in which a resin layer is interposed between a pair of metal layers.

[0029] Further, an electrode tab processing method using the electrode tab processing apparatus according to the present invention includes a first step of positioning an 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.

[0030] In addition, in the electrode tab processing method according to the present invention, at least one of the lower jig 800 and the upper jig 900 may be heated before or during the second step.

[0031] Advantageous Effects

[0032] In the electrode tab processing apparatus of a secondary battery according to the present invention and an electrode tab processing method using the electrode tab processing apparatus, a lower jig having a lower ridge portion and an upper jig having an upper concave portion are included. The lower ridge portion is provided on an upper surface of the lower jig, and the upper concave portion is configured to engage with the lower ridge portion and is provided on a lower surface of the upper jig. Among them, the electrode tab is pressed in a state where the electrode tab is positioned between the lower jig and the upper jig, whereby a cutting line can always be formed at a predetermined position.

[0033] In addition, in the electrode tab processing apparatus of a secondary battery according to the present invention and an electrode tab processing method using the electrode tab processing apparatus, since the electrode tab is positioned between the lower jig and the upper jig and then pressed, the quality of the processed electrode tab is uniform regardless of the technical level of the worker.

[0034] In addition, in the electrode tab processing apparatus of a secondary battery according to the present invention and an electrode tab processing method using the electrode tab processing apparatus, each of the lower jig and the upper jig has a structure in which a plurality of unit members are connected to each other, whereby only a specific unit member can be replaced, which can reduce the processing cost. Description of the Drawings

[0035] Figure 1 It is a partial schematic diagram of a conventional secondary battery.

[0036] Figure 2 It is an exploded perspective view of a secondary battery electrode assembly according to a first embodiment of the present invention.

[0037] Figure 3 It is a cross-sectional view of the positive electrode in the secondary battery electrode assembly according to the first embodiment of the present invention.

[0038] Figure 4 It is a top view of the secondary battery electrode assembly according to the first embodiment of the present invention.

[0039] Figure 5 It is a bottom view of the secondary battery electrode assembly according to the first embodiment of the present invention.

[0040] Figure 6 It is Figure 4 An exploded perspective view of part A of the electrode assembly shown in

[0041] Figure 7 It is an exploded perspective view of a secondary battery electrode assembly according to a second embodiment of the present invention.

[0042] Figure 8 It is a cross-sectional view of the negative electrode in the secondary battery electrode assembly according to the second embodiment of the present invention.

[0043] Figure 9 It is a top view of the secondary battery electrode assembly according to the second embodiment of the present invention.

[0044] Figure 10 It is a bottom view of the secondary battery electrode assembly according to the second embodiment of the present invention.

[0045] Figure 11 It is Figure 9 An exploded perspective view of part B of the electrode assembly shown in

[0046] Figure 12 It is a perspective view of an electrode tab processing device according to a first embodiment for processing the electrode tab of the secondary battery electrode assembly of the present invention.

[0047] Figure 13 It is Figure 12 A cross-sectional view of the electrode tab processing device shown in

[0048] Figure 14 It is Figure 12 A bottom perspective view of the upper fixture in the electrode tab processing device shown in

[0049] Figure 15It is a perspective view of an electrode tab processing apparatus according to a second embodiment for processing an electrode tab of a secondary battery electrode assembly of the present invention.

[0050] Figure 16 It is a perspective view illustrating a method of processing an electrode tab of a secondary battery electrode assembly using an electrode tab processing apparatus according to a first embodiment.

[0051] Figure 17 It is an enlarged perspective view of an electrode tab of a secondary battery electrode assembly processed by an electrode tab processing apparatus according to a first embodiment. Detailed Description

[0052] In the present application, it should be understood that the terms "comprising", "having", "including", etc. specify the presence of the stated features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0053] In addition, throughout the drawings, the same reference numerals will be used to refer to components that perform similar functions or operations. Throughout the specification, when a component is referred to as being connected to another component, a component can not only be directly connected to another component, but also a component can be indirectly connected to another component via another component. In addition, including a certain element does not mean excluding other elements, but means that such elements can also be included unless otherwise mentioned.

[0054] Hereinafter, an electrode tab processing apparatus for a secondary battery according to the present invention and an electrode tab processing method using the electrode tab processing apparatus will be described with reference to the drawings.

[0055] First, a secondary battery electrode assembly using an electrode tab processing apparatus according to the present invention will be described.

[0056] Figure 2 It is an exploded perspective view of a secondary battery electrode assembly according to a first embodiment of the present invention, and Figure 3 It is a cross-sectional view of a positive electrode in a secondary battery electrode assembly according to a first embodiment of the present invention.

[0057] As Figure 2 and Figure 3 shown, the secondary battery electrode assembly according to the present invention has a structure in which at least one positive electrode 100, at least one negative electrode 200, and at least one separator 300 are stacked.

[0058] Specifically, the separator 300 may be located between the positive electrode 100 and the negative electrode 200, on the upper surface of the uppermost negative electrode 200, or below the lowermost negative electrode 200; however, the present invention is not necessarily limited thereto.

[0059] In addition, the positive electrode lead 400 is electrically connected to the positive electrode 100, and the 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.

[0060] First, the positive electrode 100 may include a positive electrode current collector 110 and a positive electrode tab 120. In a first preferred embodiment of the present invention, the positive electrode current collector 110 has a three-layer structure in which a first resin layer 112 is interposed between a pair of aluminum layers 111.

[0061] Here, each aluminum layer of the aluminum layers has a thickness of about 0.5 μm to 2 μm, and the first resin layer is made of polyethylene terephthalate (PET) and has a thickness of about 5 μm to 10 μm; however, the present invention is not necessarily limited thereto.

[0062] Aluminum can be replaced with stainless steel, nickel, titanium, sintered carbon, or aluminum or stainless steel treated with carbon, nickel, titanium, or silver on its surface, as long as it can exhibit high conductivity without causing any chemical changes in the battery. In addition, a microscale concavo-convex pattern can be formed on its surface to increase the adhesion of the positive electrode active material, or various forms such as films, sheets, foils, meshes, porous bodies, foams, and non-woven fabric bodies can be used.

[0063] Each of the upper surface and the lower surface of the pair of aluminum layers 111 exposed to the outside is provided with a positive electrode active material layer 113.

[0064] The following can be used: layered compounds such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; lithium manganese oxide represented by the chemical formula Li 1+x Mn 2-x O4 (where x = 0 to 0.33), or lithium manganese oxides such as LiMnO3, LiMn2O3, or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, or Cu2V2O7; lithium nickel oxide of the Ni-site type represented by 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); lithium manganese represented by the chemical formula LiMn 2-x M xO2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or a lithium manganese composite oxide represented by the chemical formula Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); LiMn2O4, in which a part of Li in the chemical formula is replaced by an alkaline earth metal ion; a disulfide compound; Fe2(MoO4)3; or LiNi x Mn 2-x O4 (0.01 ≤ x ≤ 0.6) as the positive electrode active material.

[0065] In addition, the positive electrode active material can be mixed with a conductive agent and a binder, and a filler can be further added as needed. Since the conductive agent, binder, and filler are known materials, their detailed descriptions will be omitted.

[0066] Meanwhile, an uncoated portion (not shown) of the positive electrode current collector 110 where the positive electrode active material layer is not formed is stamped into a predetermined shape to form a positive electrode tab 120.

[0067] The negative electrode 200 can include 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 μm to 500 μm. The negative electrode current collector is not particularly limited as long as it exhibits high conductivity and does not cause any chemical changes in the battery. For example, the negative electrode current collector can be made of copper, stainless steel, aluminum, nickel, titanium, or sintered carbon. Alternatively, the negative electrode current collector can be made of copper or stainless steel or aluminum cadmium alloy whose surface is treated with carbon, nickel, titanium, or silver.

[0068] In addition, the negative electrode current collector can have a microscale concavo-convex pattern formed on its surface to increase the adhesion of the negative electrode active material, or can be constructed in various forms such as any one of a film, sheet, foil, net, porous body, foam body, and non-woven fabric body.

[0069] Negative electrode active material layers are provided on each of the upper surface and the lower surface of the negative electrode current collector 210. As the negative electrode active material, for example, the following can be used: carbon, such as non-graphitized carbon or graphite-based carbon; metal composite oxides, such as 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, Group 1, Group 2, and Group 3 elements of the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); 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, or Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; or silicon-based materials such as Si, SiO, SiO2, or mixtures thereof; however, the present invention is not limited thereto.)

[0070] Of course, the negative electrode active material can be further mixed with a conductive agent and a binder to form a negative electrode active material layer. Since the conductive agent and the binder are known materials, their detailed descriptions will be omitted.

[0071] Meanwhile, an uncoated portion (not shown) of the negative electrode current collector 210 where the negative electrode active material layer is not formed is punched into a predetermined shape to form a negative electrode tab 220.

[0072] The separator 300 prevents short circuits between the positive electrode 100 and the negative electrode 200 and only allows the migration of lithium ions. Preferably, the separator is made of any one selected from polyethylene, polypropylene, double-layer polyethylene / polypropylene, triple-layer polyethylene / polypropylene / polyethylene, triple-layer polypropylene / polyethylene / polypropylene, and organic fiber filter paper; however, the present invention is not limited thereto.

[0073] Figure 4 is a top view of a secondary battery electrode assembly according to a first embodiment of the present invention, Figure 5 is a bottom view of a secondary battery electrode assembly according to a first embodiment of the present invention, and Figure 6 is Figure 4 an enlarged exploded perspective view of part A of the electrode assembly shown in

[0074] will be described with reference to Figures 2 to 6 the electrical connection structure between the positive electrode tab 120 and the positive electrode lead 400.

[0075] Generally, since the positive electrode tab is made only of metal, it can be connected to the positive electrode lead by ultrasonic welding or the like. However, as described above, each of the positive electrode current collector and the positive electrode tab according to the first embodiment of the present invention has a structure in which a first resin layer is interposed between a pair of aluminum layers. That is, due to the first resin layer constituting each positive electrode tab, it is difficult to firmly fix a plurality of positive electrode tabs to each other by ultrasonic welding, and it is also difficult to firmly fix the positive electrode tab and the positive electrode lead to each other.

[0076] Therefore, in the first embodiment of the present invention, a first cutting line 121 and a first connecting portion 122 are formed along the total length direction (X-axis direction) on each positive electrode tab of the positive electrode tabs 120, and the first metal foil 600 is disposed to extend through the first cutting line 121.

[0077] More specifically, two first cutting lines 121 are disposed parallel to each other along the total length direction (X-axis direction) on each positive electrode tab of the positive electrode tabs 120 while being spaced apart from each other by a predetermined distance, and the first connecting portion 122 is formed by the first cutting lines 121.

[0078] At this time, the first connecting portion 122 is preferably slightly convex upward so that the first metal foil 600 can easily extend through the first cutting line 121. The equipment and method for performing processing to form this structure will be described later.

[0079] Meanwhile, both ends of each first cutting line of the first cutting lines 121 are preferably positioned within the positive electrode tab 120 so that the first metal foil 600 extending through the first cutting line 121 does not separate from the positive electrode tab.

[0080] When the first metal foil 600 extends through one of the two first cutting lines 121 and then extends through the other first cutting line 121, the first metal foil 600 is exposed at two edges of the positive electrode tab 120 in the width direction (Z-axis direction), while the first connecting portion 122 is located at the center (see Figure 4 ).

[0081] On the other hand, the first metal foil 600 is not exposed at two edges of the back surface of the positive electrode tab 120 in the width direction (Z-axis direction) while the middle portion of the positive electrode tab is exposed (see Figure 5 ).

[0082] Therefore, the positive electrode tabs 120 form a tab bundle through the first metal foil 600 because the first metal foil 600 is formed in the shape of a strip extending through the two first cutting lines 121 in a zigzag manner.

[0083] The positive electrode lead 400 is in close contact with a part of the positive electrode tab 120 and a part of the first metal foil 600, and is fixed thereto by ultrasonic welding.

[0084] At this time, the positive electrode lead 400 preferably faces the surface of the first metal foil 600 exposed at two edges of the positive electrode tab 120 in the width direction (Z-axis direction) because the connection and fixation between two edges of the positive electrode tab 120 in the width direction (Z-axis direction) and the positive electrode lead 400 are more effective in suppressing movement in the width direction (Z-axis direction).

[0085] Of course, it is obvious that the first metal foil 600 helps to electrically connect the positive electrode tab 120 and the positive electrode lead 400 to each other.

[0086] Meanwhile, the first metal foil 600 is preferably made of the same aluminum material as the aluminum layer 111, but the material can be changed as long as the same function can be performed.

[0087] In addition, the length of the first metal foil 600 is preferably not more than the width of the positive electrode tab 120, and the width of the first metal foil 600 is preferably slightly less than the length of the first cutting line 121.

[0088] The positive electrode lead 400 is preferably made of aluminum; however, the present invention is not necessarily limited thereto.

[0089] Figure 7 is an exploded perspective view of a secondary battery electrode assembly according to a second embodiment of the present invention, and Figure 8 is a cross-sectional view of the negative electrode in the secondary battery electrode assembly according to the second embodiment of the present invention.

[0090] The secondary battery electrode assembly according to the second embodiment of the present invention has a structure in which at least one positive electrode 100, at least one negative electrode 200, and at least one separator 300 are stacked in the same manner as in the first embodiment.

[0091] However, different from the first embodiment, in the second embodiment, the negative electrode 200 has a three-layer structure, and a second metal foil 700 is interposed between the negative electrode 200 and the negative electrode lead 500; therefore, repetitive descriptions will be omitted, and only different configurations will be described.

[0092] The negative electrode 200 may include a negative electrode current collector 210 and a negative electrode tab 220. In a second preferred embodiment of the present invention, the negative electrode current collector 210 has a three-layer structure in which a second resin layer 212 is interposed between a pair of copper layers 211.

[0093] Here, each of the copper layers has a thickness of about 0.5 μm to 2.0 μm, and the second resin layer is made of polyethylene terephthalate (PET) and has a thickness of about 3 μm to 10 μm; however, the present invention is not necessarily limited thereto.

[0094] Of course, stainless steel or the like can be used instead of copper as long as it can exhibit high conductivity without causing any chemical changes in the battery.

[0095] Negative electrode active material layers 213 are provided on each of the upper and lower surfaces of the pair of copper layers 211 exposed to the outside. The negative electrode active material has been described previously, so the description of the negative electrode active material will be omitted.

[0096] Figure 9 is a top view of a secondary battery electrode assembly according to a second embodiment of the present invention, Figure 10 is a bottom view of a secondary battery electrode assembly according to a second embodiment of the present invention, and Figure 11 is Figure 9 an enlarged exploded perspective view of part B of the electrode assembly shown in

[0097] Reference will be made to Figures 7 to 11 describe the electrical connection structure between the negative electrode tab 220 and the negative electrode lead 500.

[0098] Generally, the negative electrode tab is made only of metal, and thus can be connected to the negative electrode lead by ultrasonic welding or the like. However, as described above, each of the negative electrode current collector and the negative electrode tab according to the second embodiment of the present invention has 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 fix a plurality of negative electrode tabs to each other by ultrasonic welding, and it is also difficult to firmly fix the negative electrode tab and the negative electrode lead to each other.

[0099] Therefore, in the second embodiment of the present invention, a second cutting line 221 and a second connecting portion 222 are formed on each negative electrode tab in the negative electrode tab 220 along the total length direction (X-axis direction), and the second metal foil 700 is disposed to extend through the second cutting line 221.

[0100] More specifically, two second cutting lines 221 are disposed parallel to each other and spaced apart by a predetermined distance along the total length direction (X-axis direction) on each negative electrode tab in the negative electrode tab 220, and the second connecting portion 222 is formed by the second cutting line 221.

[0101] At this time, the second connecting portion 222 preferably bulges slightly upward so that the second metal foil 700 can easily extend through the second cutting line 221. The equipment and method for performing the processing to form this structure will be described later.

[0102] Meanwhile, both ends of each second cutting line in the second cutting lines 221 are preferably positioned within the negative electrode tab 220 so that the second metal foil 700 extending through the second cutting line 221 does not separate from the negative electrode tab.

[0103] When the second metal foil 700 extends through one of the two second cutting lines 221 and then extends through the other second cutting line 221, the second metal foil 700 is exposed at two edges in the width direction (Z-axis direction) of the negative electrode tab 220, while the second connecting portion 222 is located at the center (see Figure 9 ).

[0104] On the other hand, the second metal foil 700 is not exposed at two edges in the width direction (Z-axis direction) on the back surface of the negative electrode tab 220, while the middle portion of the negative electrode tab is exposed (see Figure 10 ).

[0105] Therefore, the negative electrode tab 220 forms a tab bundle through the second metal foil 700, because the second metal foil 700 is formed in the shape of a band extending in a zigzag manner through two second cutting lines 221.

[0106] The negative electrode lead 500 is in close contact with a part of the negative electrode tab 220 and a part of the second metal foil 700, and is fixed thereto by ultrasonic welding.

[0107] At this time, the negative electrode lead 500 preferably faces the surface of the second metal foil 700 exposed at two edges in the width direction (Z-axis direction) of the negative electrode tab 220, because the connection and fixation between the two edges in the width direction (Z-axis direction) of the negative electrode tab 220 and the negative electrode lead 500 are more effective in suppressing movement in the width direction (Z-axis direction).

[0108] Of course, it is obvious that the second metal foil 700 helps to electrically connect the negative electrode tab 220 and the negative electrode lead 500 to each other.

[0109] Meanwhile, the second metal foil 700 is preferably made of the same or similar copper material as the copper layer 211, nickel-plated copper, or nickel-copper alloy, but the material can be changed as long as the same function can be performed.

[0110] In addition, the length of the second metal foil 700 preferably does not exceed the width of the negative electrode tab 220, and the width of the second metal foil 700 is preferably slightly smaller than the length of the second cutting line 221.

[0111] The negative electrode lead 500 is made of nickel; however, the present invention is not necessarily limited thereto.

[0112] Although not shown in the figure, a secondary battery electrode assembly according to a combination of the first embodiment and the second embodiment can be provided. For example, the positive electrode has a three-layer structure in which a first resin layer is interposed between a pair of aluminum layers, the negative electrode has a three-layer structure in which a second resin layer is interposed between a pair of copper layers, and a first metal foil and a second metal foil are respectively interposed between the positive electrode tab and the positive electrode lead and between the negative electrode tab and the negative electrode lead.

[0113] Next, an electrode tab processing device will be described, which is used to process the positive electrode tab and the negative electrode tab so that the tabs are provided with cutting lines and connection portions, that is, the positive electrode tab is provided with a first cutting line and a first connection portion, and the negative electrode tab is provided with a second cutting line and a second connection portion.

[0114] Figure 12 is a perspective view of an electrode tab processing apparatus according to a first embodiment for processing an electrode tab of a secondary battery electrode assembly of the present invention, Figure 13 is Figure 12 a sectional view taken along line A-A of the electrode tab processing apparatus shown in Figure 14 is Figure 12 a bottom perspective view of an upper jig in the electrode tab processing apparatus shown in

[0115] Referring to Figures 12 to 14 , the electrode tab processing apparatus according to the present invention includes a lower jig 800 and an upper jig 900, and each of the lower jig 800 and the upper jig 900 has a shape of a rectangular hexahedron.

[0116] One surface of each electrode tab to be processed is positioned on the upper surface of the lower jig 800, and the lower surface of the upper jig 900 is positioned on the other surface of each electrode tab; however, the positions of the lower jig 800 and the upper jig 900 may be reversed.

[0117] 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 element 830.

[0118] A pair of first lower flat portions 811 are positioned on the upper surface of the first lower body 810 to be spaced apart from each other in the longitudinal direction (Z-axis direction), and a lower ridge 812 is provided between the pair of first lower flat portions 811, wherein the first lower flat portions 811 and the lower ridge 812 are configured to form a cutting line and a connecting portion of the electrode tab.

[0119] Herein, the transverse cross-section (XY plane) of the lower ridge 812 is preferably semi-circular or semi-elliptical.

[0120] The second lower body 820 may be provided in a pair, one on each side of the first lower body 810, a pair of second lower flat portions 821 may be positioned on the upper surface of the second lower body to be spaced apart from each other in the longitudinal direction (Z-axis direction), and a lower recess 822 may be provided between the pair of second lower flat portions 821.

[0121] Herein, the transverse cross-section (XY plane) of the lower recess 822 is preferably semi-circular or semi-elliptical.

[0122] The first lower body 810 and the second lower body 820 are preferably configured to be detachable so that only a specific lower body can be replaced as needed. For example, bolts and nuts (not shown) inserted through the first lower body 810 and the second lower body 820 can be used to fix the bodies or separate and replace the bodies; however, any device other than bolts and nuts can be used as long as the bodies can be fixed in a separable manner.

[0123] The first heating member 830 can be arranged to extend through the first lower body 810 and the second lower body 820 and is configured to heat the electrode tab to a predetermined temperature when forming the cutting line and the connecting portion of the electrode tab.

[0124] As described above, advantageously, in order to facilitate fastening of the metal foil, the connecting portion bulges slightly upward, and therefore, it is desirable to process the electrode tab while heating the electrode tab to a predetermined temperature so that the electrode tab can be slightly elongated.

[0125] Although the drawings show that the first heating member 830 is arranged to extend through the first lower body 810 and the second lower body 820, the first heating member 830 may not be arranged to extend through the first lower body 810 and the second lower body 820 as long as the first lower body and the second lower body can be heated.

[0126] Next, the upper fixture 900 will be described in detail. The upper fixture 900 can include a first upper body 910, a second upper body 920, and a second heating member 930.

[0127] A pair of first upper flat portions 911 are positioned on the lower surface of the first upper body 910 to be spaced apart from each other in the longitudinal direction (Z-axis direction), and an upper concave portion 912 engaged with the lower ridge portion 812 of the first lower body 810 is provided between the pair of first upper flat portions 911. In this case, the transverse cross-section (XY plane) of the upper concave portion 912 is preferably the same semi-circular or semi-elliptical shape as the lower ridge portion 812.

[0128] The second upper body 920 can be provided in pairs, one on each side of the first upper body 910. A pair of second upper flat portions 921 can be positioned on the upper surface of the second upper body to be spaced apart from each other in the longitudinal direction (Z-axis direction), and an upper ridge portion 922 engaged with the lower concave portion 822 of the second lower body 820 can be provided between the pair of second upper flat portions 921 in the longitudinal direction (Z-axis direction).

[0129] Here, the transverse cross-section (XY plane) of the upper ridge portion 922 is preferably the same semi-circular or semi-elliptical shape as the transverse cross-section of the lower concave portion 822.

[0130] The first upper body 910 and the second upper body 920 are preferably configured to be detachable so that only a specific upper body can be replaced as needed. For example, bolts and nuts (not shown) inserted through the first upper body 910 and the second upper body 920 can be used to fix the bodies or separate and replace the bodies; however, any device other than bolts and nuts can be used as long as the bodies can be fixed in a separable manner.

[0131] The second heating member 930 may be provided to extend through the first upper body 910 and the second upper body 920 and is configured to heat the electrode tab to a predetermined temperature when forming the cutting line and the connecting portion of the electrode tab.

[0132] As described above, in order to facilitate fastening of the metal foil, the connecting portion advantageously protrudes slightly upward, and therefore, it is desirable to process the electrode tab while heating the electrode tab to a predetermined temperature so that the electrode tab can be slightly elongated.

[0133] Although the drawings show that the second heating member 930 is provided to extend through the first upper body 910 and the second upper body 920, the second heating member 930 may not be provided to extend through the first upper body 910 and the second upper body 920 as long as the first upper body 910 and the second upper body 920 can be heated.

[0134] Figure 15 is a perspective view of an electrode tab processing apparatus according to a second embodiment for processing an electrode tab of a secondary battery electrode assembly of the present invention. Except for the configurations of the second lower body and the second upper body, the electrode tab processing apparatus according to the second embodiment is the same as the electrode tab processing apparatus according to the first embodiment described above.

[0135] 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 second upper body 920 is also flat.

[0136] Next, an electrode tab processing method using the electrode tab processing apparatus according to the first embodiment will be described.

[0137] Figure 16 is a perspective view illustrating a method of processing an electrode tab of a secondary battery electrode assembly using the electrode tab processing apparatus according to the first embodiment, and Figure 17 is an enlarged perspective view of an electrode tab of a secondary battery electrode assembly processed by the electrode tab processing apparatus according to the first embodiment.

[0138] Refer to Figure 12 、 Figure 16 and Figure 17, the method for processing an electrode tab 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.

[0139] The first step is a step of positioning the lower jig 800 on the lower surface of the positive electrode tab 120 and positioning the upper jig 900 on the upper surface of the positive electrode tab, wherein the first lower body 810 and the first upper body 910 are positioned to overlap a portion where a first cutting line 121 and a first connection portion 122 are to be formed.

[0140] The second step is a step of moving the lower jig 800 upward, moving the upper jig 900 downward, or simultaneously moving the lower jig upward and the upper jig downward to press the positive electrode tab 120.

[0141] When the lower jig 800 and the upper jig 900 are engaged with each other, the first connection portion 122 is processed to be slightly convex upward so as to facilitate the first metal foil to extend through the first cutting line 121.

[0142] Specifically, both side portions of the lower ridge 812 of the first lower body 810 and inner portions of the upper ridges 922 of a pair of second upper bodies 920 serve as block-shaped cutters, whereby the first cutting line 121 is formed at a position where these side portions and inner portions intersect each other.

[0143] In addition, the first connection portion 122 overlapping the lower ridge 812 of the first lower body 810 has a shape convex upward similar to the shape of the lower ridge 812, and thus, a gap is formed in the first connection portion 122 with respect to the first cutting line 121, so that the first metal foil can easily extend through the first cutting line 121.

[0144] More preferably, at least one of the lower jig 800 and the upper jig 900 is heated before or during the second step.

[0145] For example, 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, the electrode tab can be heated for a predetermined period of time, and then the second step can be performed.

[0146] This is advantageous for processing the first connection portion 122 into a slightly convex shape by providing conditions under which the electrode tab can elongate.

[0147] Meanwhile, although only the method of processing the positive tab using the electrode tab processing apparatus according to the first embodiment has been described, it is obvious that the negative tab can be processed by the same process, and the positive tab and the negative tab can be processed using the electrode tab processing apparatus according to the second embodiment.

[0148] Although the specific details of the present invention have been described in detail, those skilled in the art will understand that the detailed description only discloses the preferred embodiments of the present invention and thus does not limit the scope of the present invention. Therefore, those skilled in the art will understand that various changes and modifications are possible without departing from the scope and technical concept of the present invention, and it will be obvious that such changes and modifications fall within the scope of the appended claims.

[0149] (Description of reference numerals)

[0150] 100: Positive electrode

[0151] 110: Positive current collector

[0152] 111: Aluminum layer 112: First resin layer

[0153] 113: Positive active material layer

[0154] 120: Positive tab

[0155] 121: First cutting line 122: First connection portion

[0156] 200: Negative electrode

[0157] 210: Negative current collector

[0158] 211: Copper layer 212: Second resin layer

[0159] 213: Negative active material layer

[0160] 220: Negative tab

[0161] 221: Second cutting line 222: Second connection portion

[0162] 300: Separator

[0163] 400: Positive lead

[0164] 500: Negative lead

[0165] 600: First metal foil

[0166] 700: Second metal foil

[0167] 800: Lower jig

[0168] 810: First lower body

[0169] 811: First lower flat part 812: Lower ridge

[0170] 820: Second lower body

[0171] 821: Second lower flat part 822: Lower concave part

[0172] 830: First heating element

[0173] 900: Upper fixture

[0174] 910: First upper body

[0175] 911: First upper flat part 912: Upper concave part

[0176] 920: Second upper body

[0177] 921: Second upper flat part 922: Upper ridge

[0178] 930: Second heating element

Claims

1. An electrode tab processing device for forming a connection portion by cutting a predetermined area of each electrode tab extending in one direction of an electrode current collector so that a metal foil can be connected to the electrode tab, the electrode tab processing device comprising: A lower jig positioned on one surface of each of the electrode tabs; And An upper jig positioned on the other surface of each of the electrode tabs, wherein A pair of first lower flat portions are positioned on the upper surface of the lower jig to be spaced apart from each other in the longitudinal direction, and a lower ridge is provided between the pair of first lower flat portions, A pair of first upper flat portions are positioned on the lower surface of the upper jig to be spaced apart from each other in the longitudinal direction, and an upper concave portion configured to engage with the lower ridge is provided between the pair of first upper flat portions, and When the electrode tab is pressed in a state of being positioned between the lower jig and the upper jig, a connection portion through which the metal foil can extend is formed by a pair of cutting lines spaced apart from each other by a predetermined distance.

2. The electrode tab processing device according to claim 1, wherein The lower jig further has a lower concave portion along the longitudinal direction in the upper surface of the lower jig, and The upper jig further has an upper ridge along the longitudinal direction configured to engage with the lower concave portion on the lower surface of the upper jig.

3. The electrode tab processing device according to claim 2, wherein The lower ridge is located in the middle of the upper surface of the lower jig, and the lower concave portions are provided in pairs on both sides of the lower ridge, and The upper concave portion is located in the middle of the lower surface of the upper jig, and the upper ridges are provided in pairs on both sides of the upper concave portion.

4. The electrode tab processing device according to claim 3, wherein, The lower jig includes a first lower body having the lower ridge and a second lower body in which the lower concave portion is located, and the first lower body and the second lower body can be separated from each other.

5. The electrode tab processing equipment according to claim 3, wherein, The upper jig includes a first upper body having the upper concave portion and a second upper body on which the upper ridge is located, and the first upper body and the second upper body can be separated from each other.

6. The electrode tab processing equipment according to claim 3, wherein, The lower jig is further provided with a first heating member.

7. The electrode tab processing equipment according to claim 3, wherein, The upper jig is further provided with a second heating member.

8. The electrode tab processing equipment according to claim 3, wherein, The transverse cross-section of each of the lower ridge and the upper concave portion is semicircular or semi-elliptical.

9. The electrode tab processing equipment according to claim 3, wherein, The transverse cross-section of each of the lower concave portion and the upper ridge is semicircular or semi-elliptical.

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

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

12. The electrode tab processing method according to claim 11, wherein, Heating at least one of the lower jig and the upper jig before or during the second step.

Images