Electrode leads and corresponding lead input pallets

Abstract

The present invention relates to an electrode lead included in a pouch-type battery cell, and more specifically, to an electrode lead having an asymmetric shape so that a direction in which burrs, which inevitably occur on an electrode lead due to the characteristics of a metal plate cut by a press, are formed can be geometrically distinguished from a direction in which they are not. The present invention also provides a lead insertion pallet that can normally store an electrode lead having an asymmetric shape only in one direction, and is provided with an insertion port having a direction limiting part that interferes with the asymmetric shape and limits insertion when the electrode lead is stored in another direction. In short, the asymmetric shape makes it possible to distinguish between the top and bottom surfaces of the electrode lead, and the pallet allows the electrode lead to be stored and moved only in one of the top and bottom directions, so that the electrode lead is welded to an electrode tab in a pouch cell avoiding a portion where burrs are formed due to the press cutting process, thereby providing a pouch-type battery cell with improved stability by reducing misidentification caused by visually distinguishing between the top and bottom surfaces.

Description

[Technical Field]

[0001] This application claims priority under Korean Patent Application No. 10-2022-0049893 dated April 22, 2022, and all content disclosed in said Korean Patent Application is incorporated herein as part of this specification.

[0002] The present invention relates to press-formed electrode leads and a pallet for housing them. [Background technology]

[0003] Due to their high applicability across product lines and electrical characteristics such as high energy density, secondary batteries are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electrical sources.

[0004] These secondary batteries are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency, not only because they have the primary advantage of dramatically reducing the use of fossil fuels, but also because they produce no by-products from energy use.

[0005] Currently, widely used types of rechargeable batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of each of these individual rechargeable battery cells is approximately 2.5V to 4.5V. Therefore, when a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Alternatively, depending on the required charge and discharge capacity of the battery pack, multiple battery cells may be connected in parallel to form a battery pack. Thus, the number of battery cells included in the battery pack and the electrical connection configuration can be set in various ways depending on the required output voltage and / or charge and discharge capacity.

[0006] On the other hand, secondary batteries are generally classified into cylindrical and rectangular batteries, in which the electrode assembly is housed in a cylindrical or rectangular metal can, and pouch batteries, in which the electrode assembly is housed in a pouch-type case made of aluminum laminate sheet, depending on the shape of the battery case. The electrode assembly housed in the battery case consists of a positive electrode, a negative electrode, and a separation membrane structure interposed between the positive and negative electrodes, and is a rechargeable power generation element. It is classified into a jelly roll type, in which a long sheet-like positive electrode coated with an active material is wound with a separation membrane interposed between the positive and negative electrodes, and a stack type, in which multiple positive and negative electrodes of a predetermined size are sequentially stacked with a separation membrane interposed between them.

[0007] In this case, the pouch-type battery cell is connected to the outside of the cell via electrode leads welded to the electrode tabs, which are connected to the positive and negative electrodes, respectively, of the battery cell.

[0008] Figure 1 shows a cross-section of one side of a typical pouch cell. Referring to this, the electrode tab 12 protrudes from the electrode assembly 11, in which the negative and positive electrodes coated with active material are laminated with a separation membrane in between, and is welded to the electrode lead 2 in contact with each other in the height direction. The lead film 21, which is laminated in the width direction of the electrode lead 2, is heat-welded to the pouch, so that the electrode lead 2 extends outward from the pouch, while the pouch is sealed. Ultrasonic welding is mainly used for this welding.

[0009] On the other hand, the electrode lead 2 is generally produced by pressing and cutting a metal plate into a shape such as a rectangle, and then attaching a lead film 21 to it.

[0010] Figures 2 to 4 show the top, bottom, and side surfaces of the press-formed electrode lead 2, respectively. Referring to these drawings, it can be seen that during this process, burrs 23 are formed on the edges of the electrode lead 2 in the direction of the pressurization, i.e., downwards. These burrs 23 can cause problems during the ultrasonic welding process, potentially leading to welding defects between the electrode tab 12 and the electrode lead 2, and consequently, wire breakage.

[0011] However, since the electrode leads generally have a symmetrical shape and burrs are formed so finely that they cannot be visually detected, in the actual welding process, the direction of the burrs must be confirmed by touch during the welding process to the electrode tab to determine the direction of insertion, thus creating a problem where misidentification is possible. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The present invention was conceived against the background of the prior art described above, and aims to provide an electrode lead having an asymmetrical shape so that a top surface where no burrs are formed by the press working process can be distinguished from a bottom surface where burrs are formed.

[0013] Another technical problem of the present invention is to provide a lead feeding pallet equipped with a direction limiting section so that the electrode leads, with their upper and lower surfaces distinguished, are fed in one direction during the above-mentioned press working process.

[0014] Another technical problem of the present invention is to prevent misidentification that occurs in the process of distinguishing the difference between the upper and lower surfaces during the welding process between the electrode tab and the electrode lead, using the improved electrode lead and lead input pallet.

[0015] Another technical problem of the present invention is to prevent disconnection of the electrode tab portion by improving the bonding performance between the electrode tab and the electrode lead.

[0016] A further technical problem of the present invention is to provide an electrode lead with an improved structure, a pouch cell containing the same, a battery pack containing the pouch cell, and an electronic device containing the battery pack.

[0017] The technical problem of the present invention is not limited to the above-mentioned purposes, and other purposes and advantages of the present invention not mentioned can be understood from the following description and can be more clearly understood from the embodiments of the present invention. Also, it will be understood that the purposes and advantages of the present invention can be achieved by the means and their combinations shown in the claims.

Means for Solving the Problem

[0018] To solve the above problems, the present invention provides an electrode lead having an asymmetric shape and a lead insertion pallet having a direction restricting portion so that the electrode lead is inserted in one direction.

[0019] The means for solving these problems can be applied to an electrode lead that, in the manufacture of a pouch cell, is welded to an electrode tab and serves to connect an electrode provided on an electrode assembly to which the electrode tab is connected to the outside.

[0020] The electrode lead is a metal plate material and can be produced by press cutting. Thereby, a burr along the press cutting direction can be formed along an edge of one of the upper and lower surfaces of the electrode lead.

[0021] A lead film that extends along the width direction of the electrode lead and protrudes in the width direction on both sides more than the electrode lead can be laminated on a part of the surface of the electrode lead.

[0022] The shape of the edge of the electrode lead can be formed so as to have a predetermined asymmetric shape when viewed from the side where the burr is formed. At this time, the shape of the edge of the electrode lead may have a shape in which the asymmetric shape is inverted when viewed from the side where the burr is not formed.

[0023] The asymmetric shape may be asymmetric with respect to a virtual axis (X) passing through the center of the electrode lead so as to be parallel to the length direction of the electrode lead.

[0024] The asymmetric shape may be asymmetric with respect to a virtual axis (Y) passing through the center of the electrode lead so as to be arranged in the width direction of the electrode lead.

[0025] The asymmetric shape may be point-asymmetric with respect to the center of the electrode lead.

[0026] The electrode lead can have the asymmetric shape simultaneously with the production of the electrode lead. That is, the electrode lead can be cut so as to have an asymmetric shape from the process of being cut by pressing.

[0027] In contrast, the asymmetric shape of the electrode lead can also be formed by further processing after the production of the electrode lead.

[0028] The asymmetric shape can include a chamfered shape provided at one corner.

[0029] The asymmetric shape can include concavo-convex provided at an edge portion.

[0030] One end portion of the electrode lead is a portion welded to the electrode tab, and the asymmetric shape can be formed avoiding the welding portion. Also, the asymmetric shape can be formed at the other end portion in the length direction of the welded portion.

[0031] The asymmetric shape can be formed with respect to the shape of the edge of the lead film.

[0032] The electrode lead according to an embodiment of the present invention can be cut by pressing into a pentagonal shape with a chamfered shape added to one corner of a rectangle, extend in the width direction, be laminated on a part of the surface of the electrode lead, and include a lead film protruding and extending on both sides in the width direction from the electrode lead.

[0033] In this case, the chamfered shape may be formed on one of the corners of the other end of the portion that is welded to the electrode tab, relative to the lead film.

[0034] The electrode leads can be housed in a lead input pallet that stacks and stores them.

[0035] The pallet may include an input port for accommodating the electrode leads, and a direction limiting section that restricts the direction in which the electrode leads are inserted.

[0036] The direction limiting portion may be shaped such that, when the electrode lead is inserted in either the up or down direction, it does not interfere with the shape of the edge of the electrode lead, but when it is inserted in the other direction, it interferes with the shape of the edge of the electrode lead, thereby restricting insertion or preventing proper storage.

[0037] The pallet can be formed to accommodate electrode leads equipped with lead films. In this case, it may further include lead film receiving openings for accommodating the widthwise protrusions of the lead film from the electrode leads.

[0038] The input port may be such that the electrode leads are inserted vertically, or it may be such that they are inserted perpendicular to the input port.

[0039] The input port may accommodate one or more electrode leads.

[0040] Multiple input ports can be provided on a single pallet.

[0041] Multiple input ports can be provided side-by-side on a single pallet in the width direction and / or length direction.

[0042] The direction limiting portion may have a shape that is complementary to or corresponding to the asymmetrical shape of the electrode lead.

[0043] The direction limiting portion can be formed at a position corresponding to the asymmetrical shape provided on the edge of the lead film.

[0044] A pallet according to an embodiment of the present invention may also be a pallet equipped with a lead film storage opening, in which a plurality of electrode leads are stacked and stored, and the input opening has a directional restricting portion with a shape corresponding to the electrode leads, with a chamfered shape provided at one corner, and can accommodate lead films.

[0045] On the other hand, the present invention provides an improved electrode lead, a pouch-type secondary battery containing the same, a battery pack containing the pouch-type secondary battery, and an electronic device that includes the battery pack as a power source.

[0046] The electronic device may be selected from, for example, a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric motorcycle, an electric golf cart, or a power storage system.

[0047] Since the structure and manufacturing methods of these electronic devices are well known in the industry, a detailed explanation thereof is omitted in this specification. [Effects of the Invention]

[0048] This invention provides an improved electrode lead that allows the upper and lower surfaces of the electrode lead to be visually distinguishable by processing the electrode lead into an asymmetrical shape. This prevents misidentification that can occur when distinguishing between surfaces where burrs are formed and surfaces where burrs are not formed by conventional press processing, which is done solely by touch. In other words, when the electrode tab and electrode lead are welded, the burrs can hinder the joint, potentially leading to welding defects and wire breakage. This invention provides an improved electrode lead that prevents this possibility of wire breakage by ensuring a clear distinction between the upper and lower surfaces of the electrode lead.

[0049] In another aspect, the present invention can achieve its objective without affecting the welding by forming the asymmetric shape such that the electrode lead is formed to avoid the portion that is welded to the electrode tab.

[0050] In another aspect, the present invention can achieve its objective without affecting the shape of the metal portion of the electrode lead by forming the asymmetric shape on the lead film.

[0051] In another aspect, the present invention provides a lead input pallet equipped with an input opening into which the electrode leads having the asymmetrical shape are inserted and stored in only one direction, thereby enabling the electrode leads to be stored in a manner that distinguishes between the burr-formed side and the non-burr-formed side until the electrode leads and electrode tabs are welded together.

[0052] In yet another aspect, the present invention can provide a lead input pallet in which a plurality of input ports are arranged side by side in the width direction and / or length direction.

[0053] In addition, the present invention can achieve various other effects, which will be explained in each embodiment, or, in cases where such effects can be easily inferred by an ordinary person, such explanations will be omitted. [Brief explanation of the drawing]

[0054] [Figure 1] This is a side cross-sectional view showing how the electrode tab and electrode lead are welded together in a typical pouch cell. [Figure 2] This is a plan view showing the upper surface of an electrode lead with a lead film attached. [Figure 3] This is a plan view showing the lower surface of the electrode lead to which the lead film is attached, and the area where burrs have been formed by press cutting. [Figure 4]This is a side view of a typical rectangular electrode lead with a lead film attached, and a side view showing the area where burrs have been formed by press cutting. [Figure 5] This is a plan view showing the top surface of an electrode lead with a chamfered, asymmetrical shape. [Figure 6] This is a plan view showing a single unit of lead input port shaped to accommodate an asymmetrical, chamfered electrode lead. [Figure 7] This is a plan view showing how electrode leads with a chamfered, asymmetrical shape are appropriately housed in a unit of lead input opening with a corresponding shape, without any interference occurring. [Figure 8] This is a plan view illustrating how interference occurs when an electrode lead with a chamfered, asymmetrical shape is mistakenly placed into a lead input unit of a corresponding shape. [Figure 9] This is a plan view of a lead input pallet, which has multiple input slots arranged side-by-side, each shaped to accommodate beveled, asymmetrical electrode leads. [Modes for carrying out the invention]

[0055] The aforementioned objectives, features, and advantages will be described in detail below with reference to the accompanying drawings, so that a person with ordinary skill in the art to which the present invention pertains can easily implement the technical concept of the present invention. In describing the present invention, if a specific description of known technology according to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0056] While expressions such as "first," "second," etc., are used to indicate various components, these components are, of course, not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0057] In this specification, unless otherwise specified, each component may be singular or plural.

[0058] In the following, the placement of any configuration "above (or below)" a component or "above (or below)" a component means not only that the configuration is placed in contact with the upper (or lower) surface of the component, but also that other configurations may be interposed between the component and any configuration placed on (or below) it.

[0059] Furthermore, where it is stated that one component is “linked,” “joined,” or “connected” to another component, it should be understood that the components may be directly linked to or connected to one another, but may also be “interposed” between each component, or each component may be “linked,” “joined,” or “connected” through other components.

[0060] As used herein, singular expressions include plural expressions unless otherwise explicitly stated in the context. Terms such as “composed of” or “including” in this application should not be interpreted as necessarily including all of the multiple components or steps described in the specification, but rather as meaning that some of the components or steps may not be included, or that further components or steps may be included.

[0061] In this specification, when we refer to "A and / or B," we mean A, B, or A and B unless otherwise specified, and when we refer to "C~D," we mean C or greater and D or less unless otherwise specified.

[0062] For the sake of explanation, in this specification, the directions of the long and short sides of the plane constituting the electrode lead are referred to as the length direction (X direction) and the width direction (Y direction), respectively. The direction perpendicular to the same plane is referred to as the height direction (Z direction).

[0063] The present invention relates to electrode leads that are included in a pouch-type secondary battery cell and welded to an electrode tab.

[0064] A typical pouch cell 1 includes an electrode assembly 11, an electrode tab 12 connected to the electrode assembly 11, an electrode lead 2 connected to the electrode tab 12, a lead film 21 surrounding the electrode lead 2, and a pouch containing the electrode assembly 11 and the electrode tab 12, which is welded and sealed on the lead film 21.

[0065] The electrode assembly 11 has a structure in which electrode plates (positive electrode plate and negative electrode plate), each coated with an active material on one or both sides, are stacked multiple times with a separation membrane in between. The electrode tab 12 may include a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate.

[0066] In the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be any active material known in the industry.

[0067] The positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x Lithium manganese oxides (LiMnO2) such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Lithiated nickel oxide, represented as nickelsite type (LiMn), is a type of nickel oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 2-x M xLithium manganese complex oxides, such as O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which part of the lithium in the chemical formula is replaced with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3; or complex oxides formed by combinations thereof, are mainly composed of lithium intercalation materials, and are not limited to the types mentioned above.

[0068] The positive electrode current collector has a thickness of, for example, 3 to 500 μm. These positive electrode current collectors are not particularly limited as long as they do not cause chemical changes in the battery and are conductive. For example, stainless steel, aluminum, nickel, titanium, plastic carbon, or aluminum or stainless steel surfaces treated with carbon, nickel, titanium, silver, etc., can be used. The electrode current collector can also have fine irregularities formed on its surface to increase the adhesion strength of the positive electrode active material, and can take various forms such as films, sheets, foils, nets, porous materials, foams, and nonwoven fabrics.

[0069] The positive electrode active material may be further mixed with conductive materials. These conductive materials are added, for example, in an amount of 1 to 50% by weight based on the total weight of the mixture containing the positive electrode active material. These conductive materials are not particularly limited as long as they do not cause chemical changes in the battery and have high conductivity. For example, graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives can be used.

[0070] The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode current collector, and may further contain components such as the above-described conductive material, binder, solvent, etc. as necessary.

[0071] The negative electrode current collector has, for example, a thickness of 3 to 500 μm. These negative electrode current collectors are not particularly limited as long as they do not cause a chemical change in the battery and have conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, plastic carbon, those surface-treated with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, etc. can be used. Also, similar to the positive electrode current collector, fine irregularities can be formed on the surface to strengthen the binding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven fabric bodies, etc.

[0072] The negative electrode active material is, for example, carbon such as hard carbonized carbon, 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, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0<x≦1; 1≦y≦3; 1≦z≦8) metal composite oxides; lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; 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, etc. can be used.

[0073] The electrode tab 12 may be formed by a part of the electrode plate not coated with the active material protruding and extending outward from the laminated structure of the electrode plate and the separator. The parts extending from the plurality of laminated electrode plates can overlap each other to form the electrode tab 12.

[0074] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0075] Figure 1 is a side cross-sectional view showing how the electrode tab 12 and electrode lead 2 are welded together in a typical pouch cell 1.

[0076] Referring to Figure 1, both the electrode tab 12 and the electrode lead 2 may be made of electrically conductive metal. In this way, the electrode tab 12 and the electrode lead 2 can be stacked and overlapped in the height direction, with some sections overlapping in the length direction, and these overlapping sections can be welded together to form an electrical connection. The welding may be, for example, ultrasonic welding. However, the welding method is not limited to this.

[0077] The electrode leads 2 can then protrude outside the pouch even after the pouch, which is insulated via the lead film 21, is sealed, allowing the battery cell to be connected to electronic devices or the like.

[0078] Figure 2 is a plan view showing the top surface of a typical rectangular electrode lead 2 on which the lead film 21 is provided; Figure 3 is a plan view showing the bottom surface of the electrode lead 2 on which the lead film 21 is provided, and the area where burrs 23 are formed by press cutting; and Figure 4 is a side view showing the side of the electrode lead 2 on which the lead film 21 is provided, and the area where burrs 23 are formed by press cutting.

[0079] Referring to Figures 2 to 4, the electrode lead 2 may be a rectangular metal plate having a predetermined width in the width direction (Y) and extending in the length direction (X), with the length being even longer than the width. These electrode leads 2 are metal plates that can be manufactured by cutting the edges by pressing, and the shape of the edges thus processed may be rectangular. The rectangle may have a length in the length direction that is longer than the length in the width direction.

[0080] A lead film 21 that further protrudes in the width direction is attached to the electrode lead 2. The pair of lead films 21 may be welded to the upper and lower surfaces of the electrode lead 2, respectively, and their widthwise ends may be welded to each other. This allows the gap between the lead film 21 and the electrode lead 2 to be completely sealed.

[0081] Referring to Figures 3 and 4, during the press working process, irregular burrs 23 may be formed on the electrode lead 2 along the cut edge in the direction of press pressure. When welding the electrode tab 12 and the electrode lead 2, if the surface on which these burrs 23 are formed is in contact with the electrode tab 12, welding defects and wire breakage problems may occur. Therefore, the welding can be performed with the surface of the electrode lead 2 that does not have burrs 23 in contact with the electrode tab.

[0082] In this regard, in order to enable visual (geometric) distinction between the surface on which the burr 23 is formed and the surface on which the burr 23 is not formed, the embodiment provides an electrode lead 2 having an asymmetrical shape 22 in the shape of its edge.

[0083] Figure 5 is a plan view showing the top surface of the electrode lead 2 having a chamfered asymmetric shape 22. Referring to this, the electrode lead 2 may include an asymmetric shape 22 such that, due to the shape of its edges, the patterns on the top and bottom surfaces differ when they are inverted upwards, allowing for visual identification of which surface is facing upwards.

[0084] These asymmetrical shapes 22 function as follows: when the electrode leads 2 are housed in the pallet described later, if the electrode leads are inserted in the wrong direction, they interfere with a specific shape (direction limiting section) of the pallet, restricting insertion; and if the electrode leads are inserted in the correct direction, they do not interfere with the specific shape (direction limiting section) of the pallet, allowing insertion.

[0085] The asymmetrical shape 22 may be a shape that is asymmetrical with respect to a virtual axis (X) that is aligned with the length direction of the electrode lead 2 and passes through its center, and / or a shape that is aligned with the width direction of the electrode lead 2 and passes through a virtual axis (Y) that passes through its center.

[0086] For example, if the electrode lead 2 is flipped upside down with respect to the X-axis, the shape of the outline of the electrode lead 2 may differ when viewed from the same direction.

[0087] Furthermore, if the electrode lead 2 is flipped upside down with respect to the Y-axis, the shape of the outline of the electrode lead 2 may differ when viewed from the same direction.

[0088] Preferably, the asymmetric shape 22 can be asymmetrical with respect to both the X-axis and the Y-axis. These asymmetric shapes 22 can be provided on the electrode lead 2 itself, excluding the lead film 21.

[0089] The asymmetrical shape 22 can be formed simultaneously with the edge cutting process of the electrode lead 2. That is, the electrode lead 2 can be cut into a shape including the asymmetrical shape 22 from the moment its edge is first cut by pressing. In this case, there is an advantage that the direction of the burrs 23 generated during the edge cutting process and the direction of the burrs generated during the press cutting process to form the asymmetrical shape 22 can coincide.

[0090] Furthermore, in this case, there is an advantage that the shape of the edge of the electrode lead 2 when viewed from the direction in which the burr 23 is formed is not only different from the shape of the edge of the electrode lead 2 when viewed from the direction in which the burr 23 is not formed, but each is determined to a specific shape. In other words, because the direction in which the burr 23 is formed and the asymmetrical shape 22 have a specific relationship with each other, the direction in which the burr 23 is formed can be determined simply by checking the shape of the edge of the electrode lead 2.

[0091] However, even if the asymmetrical shape 22 is not necessarily formed at the same time as the edge shape of the electrode lead 2, the above-mentioned effects can be obtained similarly if the asymmetrical shape 22 is formed by an automated process while the direction of the burr caused by edge processing of the electrode lead 2 is determined.

[0092] The asymmetrical shape 22 may be a chamfered shape provided on one corner of the rectangular electrode lead 2. The electrode lead 2 including the chamfered shape can be manufactured by cutting off one corner of an existing rectangular electrode lead 2, or by cutting a metal sheet material into a pentagon including the chamfered shape from the beginning.

[0093] By chamfering one corner of the four corners of the electrode lead 2, an asymmetrical shape in the X and Y axes can be realized without significantly reducing the material of the electrode lead 2. Furthermore, partially cutting off the corner portion has little to no effect on the process of welding the electrode lead 2 to the busbar or the like.

[0094] Asymmetrical shapes can be created mainly by the cutting process of the electrode leads 2. However, if these asymmetrical parts (cut parts) are located inside the pouch or in the sealing area of ​​the pouch edge, the sharp corners of the cut parts may break the insulating layer on the inner surface of the pouch, or it may be difficult to seal the pouch edge.

[0095] For these reasons, the asymmetrical shape can be designed to be positioned outside the pouch.

[0096] In another embodiment, the asymmetric shape 22 may be an uneven surface provided on the edge portion of the shape of the edge of the electrode lead 2. The uneven surface may be uneven in the X-axis direction or uneven in the Y-axis direction.

[0097] These asymmetrical shapes 22 can be provided at corner or edge locations that are not located between the welding point between the electrode tab and the electrode lead 2 (the welding point at one end of the electrode lead in the longitudinal direction) and the welding point between the electrode lead 2 and the busbar (the welding point at the other end of the electrode lead in the longitudinal direction). This prevents the phenomenon of increased resistance of the electrode lead 2 with the asymmetrical shape 22.

[0098] The asymmetrical shape 22 can be formed to avoid the one end of the electrode lead 2 that overlaps with the electrode tab 12 and is welded. For example, the asymmetrical shape 22 can be formed on the other end in the longitudinal direction of the end of the electrode lead 2 that is welded. As a result, the asymmetrical shape 22 may not affect the welding between the electrode lead 2 and the electrode tab 12.

[0099] On the other hand, the electrode lead 2 of the embodiment may include a lead film 21 laminated on a part of its surface, extending in the width direction and protruding further than the width of the electrode lead 2, and the asymmetric shape 22 can be provided with respect to the shape of the edge of the lead film 21, thereby achieving the objective without affecting the shape of the metal part.

[0100] For example, the lead film 21 can be made asymmetrical with respect to the X-axis by, for instance, by providing a chamfered edge at the corner of the lead film 21, or by setting the distance the lead film 21 extends from the electrode lead 2 to one side in the width direction to be different from the distance it extends to the other side in the width direction. Of course, since the lead film 21 itself is positioned biased to one side in the length direction relative to the electrode lead 2, the arrangement of the lead film 21 with respect to the electrode lead 2 itself can embody asymmetry with respect to the Y-axis.

[0101] The electrode leads 2, including the asymmetrical shape 22, can be loaded into a lead loading pallet 3 and stacked for storage. The lead loading pallet 3 may include a loading port 31 into which the electrode leads 2 are loaded, and the loading port 31 may include a direction limiting section 32 that ensures the electrode leads 2 are loaded in only one direction.

[0102] Figure 6 is a plan view showing a unit of lead input port 31 with a shape corresponding to the beveled asymmetric shape 22 electrode lead 2; Figure 7 is a plan view showing how the electrode lead 2 with the beveled asymmetric shape 22 is appropriately housed in a unit of lead input port 31 with a corresponding shape, so that no interference occurs; and Figure 8 is a plan view showing how the electrode lead 2 with the beveled asymmetric shape 22 is incorrectly housed in a unit of lead input port 31 with a corresponding shape, so that interference occurs.

[0103] Referring to Figures 6 to 8, the direction limiting portion 32 is such that when the electrode lead 2 is inserted in either the up or down direction (the correct direction), it is stored normally without interference, but when it is inserted in any other direction (the incorrect direction), it interferes with the asymmetrical shape 22 of the electrode lead 2, thereby limiting its insertion.

[0104] The direction limiting portion 32 may be complementary to or corresponding to the asymmetrical shape 22 of the electrode lead 2. For example, the direction limiting portion 32 may include a tapered shape corresponding to the electrode lead 2 provided with the chamfered asymmetrical shape 22. The shape of these direction limiting portions 32 is sufficient if it interferes with the electrode lead 2 when the electrode lead 2 is inserted in a direction not facing the asymmetrical shape 22, thereby preventing the insertion of the electrode lead 2. For example, the shape of the direction limiting portion 32 may vary as long as it interferes with the portion where the asymmetrical shape 22 is not provided (another corner portion) when the electrode lead 2 is inserted in an inverted state. In other words, the shape of the direction limiting portion is not necessarily limited to a tapered shape.

[0105] The electrode lead 2 can be inserted into the input port 31 in the vertical direction. In other words, the electrode lead 2 can be inserted in the direction normal to the electrode lead 2.

[0106] Figure 9 is a plan view of a lead input pallet 3 in which multiple input ports 31, each shaped to correspond to the beveled, asymmetrical electrode lead 22, are arranged side by side. Referring to this, multiple input ports 31 can be arranged side by side in the length and / or width directions on a single lead input pallet 3.

[0107] Furthermore, the input port 31 may be open in the height direction to accommodate multiple electrode leads 2 stacked together.

[0108] Referring further to Figures 6 to 8, the input port 31 may include a lead film receiving port 33 that extends further in the width direction, provided that the shape is suitable for receiving the lead film 21 provided on the electrode lead 2.

[0109] The direction limiting portion 32 can be formed in the lead film housing opening 33 to correspond to the asymmetric shape 22 of the electrode lead 2 provided on the lead film 21.

[0110] The electrode leads 2, which have the aforementioned asymmetrical shape, can be supplied to the lead input pallet 3 with the lead film 21 attached to them. The electrode leads 2 supplied in this manner can be stored in a stacked manner through a plurality of input openings 31 that are open above the lead input pallet 3.

[0111] The lead input pallet 3, which contains the multiple electrode leads 2, can be moved near the welding device for the electrode tabs and electrode leads of the electrode assembly, thereby providing the electrode leads 2 to the welding device. At this time, since the electrode leads 2 are correctly aligned in their orientation, they can be welded directly to the electrode tabs in the direction they are supplied from the pallet 3.

[0112] The embodiments described above should be understood to be illustrative and not restrictive in all respects, and the scope of the present invention is indicated more by the claims described below than by the detailed description above. The meaning and scope of the claims described below, as well as any modifications and variations conceivable from their equivalent concepts, should be interpreted as being included within the scope of the present invention.

[0113] As described above, the present invention has been explained with reference to the illustrative drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and it is obvious to an ordinary person of the art that various modifications can be made within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described and explained while embodiments of the present invention have been described above, it is natural to acknowledge that the effects that can be predicted by such configuration should also be acknowledged. [Explanation of Symbols]

[0114] 1 pouch cell 11 Electrode assembly 12 Electrode Tabs 2 electrode leads 21 Lead film 22 Asymmetrical shapes 23 Bali 3 Lead input pallet 31 Inlet 32 Directional limiting section 33 Lead film storage slot X-length direction Y width direction Z (height direction)

Claims

1. A lead input pallet for stacking and storing battery electrode leads, which have been press-formed to have a width direction and a length direction, in an up-and-down direction, An input port into which the press-formed electrode leads are inserted; and A directional limiting section is included that, when the electrode leads are inserted with their vertical orientations aligned, no interference occurs with the shape of the edge of the electrode leads, and when the electrode leads are inserted with their vertical orientations misaligned, interference occurs and the insertion is restricted. The electrode lead is A burr formed on either the upper or lower surface of the electrode lead is formed due to press cutting. The shape of the edge (outline) of the electrode lead is, When viewed from the side where the burr is formed, it is formed in a predetermined asymmetrical shape, When viewed from the side where the burr is not formed, the asymmetrical shape is formed in an inverted shape. Lead input pallet.

2. The electrode lead has an edge shape that is longer in the length direction than in the width direction. The lead input pallet according to claim 1.

3. The aforementioned asymmetrical shape is asymmetrical with respect to a virtual axis (X) passing through the center of the electrode lead, so as to be aligned with the longitudinal direction. The lead input pallet according to claim 1.

4. The aforementioned asymmetrical shape is asymmetrical with respect to a virtual axis (Y) passing through the center of the electrode lead, so as to be aligned with the width direction. The lead input pallet according to claim 3.

5. The aforementioned asymmetrical shape is asymmetrical with respect to a virtual axis (Y) passing through the center of the electrode lead, so as to be aligned with the width direction. The lead input pallet according to claim 1.

6. The asymmetrical shape includes a chamfered shape provided at one corner of the edge shape. The lead input pallet according to claim 1.

7. The aforementioned asymmetrical shape includes an uneven surface provided at the edge portion of the edge shape, The lead input pallet according to claim 1.

8. The electrode lead has one end in the longitudinal direction that is welded to the electrode tab in overlapping position. The asymmetrical shape is formed in a position that avoids the one end of the electrode lead that is welded to the electrode tab. The lead input pallet according to claim 1.

9. The aforementioned asymmetrical shape is provided at the other end in the longitudinal direction of the electrode lead, The lead input pallet according to claim 8.

10. The electrode lead includes a lead film laminated on the surface of the electrode lead, extending along the width direction and protruding further in the width direction than the electrode lead. The lead input pallet according to claim 1.

11. The aforementioned asymmetrical shape is provided with respect to the shape of the edge of the lead film. Lead input pallet according to claim 10.

12. The direction limiting portion has a shape complementary to the asymmetric shape of the electrode lead. The lead input pallet according to claim 1.

13. The direction limiting portion has a shape corresponding to the asymmetric shape of the electrode lead. The lead input pallet according to claim 1.

14. The electrode leads are inserted vertically into the lead input pallet through the input opening. The lead input pallet according to claim 1.

15. Multiple input ports are provided side by side in the width and length directions of the electrode leads. The lead input pallet according to claim 1.

16. The electrode lead surface further includes a lead film receiving opening that can accommodate a lead film provided along the width direction, The lead input pallet according to claim 10 or 11.

17. The direction limiting portion is formed at a position corresponding to the asymmetrical shape provided on the lead film. The lead input pallet according to claim 16.

18. Multiple input ports are provided side by side in the width and length directions of the electrode leads. The lead input pallet according to claim 16.

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