Pouch-shaped battery cell and method for manufacturing the same

Abstract

The present invention relates to a pouch-shaped battery cell and a manufacturing method thereof, wherein the pouch-shaped battery cell manufacturing method includes an electrode assembly preparation step (S10), an electrode lead preparation step (S20), a first welding step (S30), a second welding step (S40), a film bonding step (S50), a packaging step (S60), an electrolyte injection step (S70), and a sealing step (S80), and the pouch-shaped battery cell is manufactured by the pouch-shaped battery cell manufacturing method. According to the present invention, not only can the weight of the electrode lead be greatly reduced to improve the lightweight, and can the electrode sheet stacked in multiple layers have a strong bonding property to the electrode lead to have excellent durability against physical impact, but also can realize a pouch-shaped battery cell with high output and capacity.

Description

Technical Field

[0001] The present invention relates to a pouch-shaped battery cell and a method for manufacturing the same, and more particularly, to a pouch-shaped battery cell and a method for manufacturing the same that can improve productivity and durability and achieve high output and capacity by forming a metal lead from a friction-welded clad metal so that it can be laser-welded with an electrode sheet. Background Art

[0002] Recently, the semiconductor, display device, and secondary battery industries, which are core components of IT equipment, have attracted attention.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged, so they are widely applicable and used in various fields such as small electronic products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game consoles, power tools and electric bicycles, as well as large products requiring high output such as electric vehicles or hybrid vehicles, and power storage devices and backup power storage devices that store generated electricity or renewable energy.

[0004] General types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel hydride batteries, nickel-zinc batteries, etc., and although unit secondary batteries (i.e., battery cells) with a predetermined voltage have angular, cylindrical, pouch-shaped, etc. shapes, compared with angular or cylindrical shapes, pouch-shaped battery cells not only have thin thickness and light weight and can be manufactured into various shapes and forms, but also have excellent efficiency and heat dissipation per unit volume area and are easy to stack into multiple layers, so the proportion of pouch-shaped battery cells used is gradually increasing.

[0005] A typical pouch-shaped battery cell is composed of an electrode assembly, a pouch-shaped case, and electrode leads.

[0006] The electrode assembly is configured to include an anode plate having an anode sheet protrudingly formed on one side, a cathode plate having a cathode sheet protrudingly formed on one side, and a separation membrane located between the anode plate and the cathode plate, and the electrode assembly is stacked to form a stacked or folded structure depending on the output voltage or charge and discharge capacity required in the battery cell.

[0007] At this time, the anode plate and the cathode plate are punched or notched so that the anode piece is protrudingly formed on the anode plate, and the cathode piece is protrudingly formed on the cathode plate.

[0008] The bag-shaped case is configured to house the electrode assembly, wherein it is made of an aluminum laminate film to satisfy electrolyte resistance for preventing liquid leakage of an electrolyte injected into the inside and excellent moldability.

[0009] The electrode lead is composed of an anode lead and a cathode lead, wherein one end of the anode lead contacts the anode sheet inside the bag-shaped case and one side protrudes outside the bag-shaped case, and one end of the cathode lead contacts the cathode sheet inside the bag-shaped case and one side protrudes outside the bag-shaped case.

[0010] In addition, an anode lead and a cathode lead respectively contacting the anode sheet and the cathode sheet of the electrode assembly stacked in multiple layers are electrically connected to the anode sheet and the cathode sheet to output electricity generated in the electrode assembly to the outside.

[0011] In the early stages of the development of pouch-shaped battery cells, the electrical connections were made by welding, and because conventional cathode leads used nickel or nickel-plated copper, welding to the cathode sheet was easy to achieve. However, with the use of expensive nickel, there was a drawback of increased manufacturing costs.

[0012] In addition, the traditional anode lead wire cannot be welded firmly because it is made of aluminum, and there is a problem that the welded part is easily corroded by salt water.

[0013] Accordingly, in recent years, welding has been used to electrically connect electrode sheets and electrode leads. However, the anode lead is made of aluminum material, and is therefore welded using ultrasonic welding, which has high energy density due to its material properties of high thermal conductivity and high reflectivity. As a result, not only does it have the defect of frequent poor welding of electrode sheets configured in multiple layers, but the durability of the joints is reduced, making them easily damaged by external vibrations or impacts, resulting in difficulty in stably achieving high output and capacity.

[0014] Furthermore, since ultrasonic welding has low energy density, when the number of electrode sheets stacked in multiple layers increases, the surface area of ​​the electrode sheet needs to be formed wider, so there is also a drawback that it causes problems in manufacturing.

[0015] Prior art literature

[0016] Patent Literature

[0017] (Patent Document 0001) Korean Patent Publication No. 10-2009-0114126 Summary of the invention

[0018] Technical issues

[0019] In order to solve the above conventional defects, an object of the present invention is to provide a pouch-shaped battery cell and a method for manufacturing the same in which metal leads are formed by friction-welding a clad metal so as to be laser-welded to an electrode tab to improve weldability with the electrode tab.

[0020] Technical Solution

[0021] In order to achieve the above object, the method for manufacturing a pouch-shaped battery cell of the present invention comprises the following steps:

[0022] Electrode assembly preparation step S10, preparing an electrode assembly consisting of an anode plate 101, a separation membrane 102 and a cathode plate 103;

[0023] An electrode lead preparation step S20 is to prepare electrode leads made of clad metal to be welded to the anode sheet 101a formed on the anode plate 101 and the cathode sheet 103a formed on the cathode plate 103;

[0024] The first welding step S30 is to laser weld the anode sheet 101a and one end of the anode lead 201 made of the clad metal;

[0025] The second welding step S40 is to laser weld the cathode sheet 103a and one end of the cathode lead 202 made of the clad metal;

[0026] Film bonding step S50, bonding the sealing film 30 to the anode lead 201 and the cathode lead 202 respectively;

[0027] After the sealing film 30 is bonded, a packaging step S60 is performed to house the electrode assembly 10 in the bag-shaped case 40;

[0028] An electrolyte injection step S70 of injecting the electrolyte into the bag-shaped case 40 encapsulating the electrode assembly 10; and

[0029] In the sealing step S80 , the bag-shaped case 40 filled with the electrolyte is sealed.

[0030] The electrode lead preparation step S20 includes the following steps:

[0031] Friction welding step S201: copper bars and aluminum bars are mounted on a friction welding machine for welding;

[0032] Rolling step S202, processing the friction welded joint body into a thin plate shape; and

[0033] In the cutting step S203 , the electrode lead 20 is cut according to the size so that copper and aluminum are arranged at both ends of the rolled joint body.

[0034] The friction welding step S201 includes the following steps:

[0035] Material preparation step S201a, installing the copper bar and the aluminum bar on the tray of the friction welding machine respectively;

[0036] A first rotating step S201b, rotating the copper bar and the aluminum bar mounted on the friction welding machine in opposite directions at a rotation speed of 1600 to 2200 rpm; and

[0037] In the joining step S201c, the copper rod and the aluminum rod are joined by bringing their opposing surfaces into close contact with each other while applying a pressure of 7 to 20 tons in a direction toward the contact surface for a predetermined time.

[0038] In one embodiment, the friction welding step S201 further includes the following steps:

[0039] A second rotating step S201d, rotating the joint body formed by joining the copper bar and the aluminum bar in one direction; and

[0040] In the bead removing step S201e, the bead removing blade is brought into close contact with the outer peripheral surface of one side of the rotating bonded body and is moved to the other side of the bonded body to remove the weld beads at the bonded portion.

[0041] The rolling step S202 includes the following steps:

[0042] A first rolling step S202a, putting the friction-welded joint body of the copper bar and the aluminum bar into a rolling mill to be rolled into a uniform thin plate of a predetermined thickness; and

[0043] The second rolling step S202b is to roll the copper portion of the thin plate after the first rolling step to be thinner than the aluminum portion.

[0044] The pouch-shaped battery cell of the present invention is manufactured by the pouch-shaped battery cell manufacturing method described above.

[0045] Beneficial Effects

[0046] According to the present invention, the electrode lead is formed using a clad metal formed by friction welding copper having excellent conductivity and aluminum having light weight, so that the weight of the electrode lead can be greatly reduced, thereby achieving an effect of improving weight reduction.

[0047] In addition, as the weldability of the electrode sheet and the electrode lead is greatly improved, laser welding with high energy density can be achieved, thereby maintaining strong bonding of the electrode sheet and the electrode lead stacked in multiple layers, thereby having excellent durability against physical impact.

[0048] In addition, even without using expensive nickel, the electrode lead can be formed using a coated metal formed by friction welding copper with excellent conductivity and aluminum with light weight, thereby having the effect of being able to realize a pouch-shaped battery cell with high output and capacity along with the reliability and safety of withstanding high output power. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a perspective view showing a pouch-shaped battery cell according to the present invention.

[0050] Figure 2 It is an exploded perspective view showing a pouch-shaped battery cell according to the present invention.

[0051] Figure 3 It is a side cross-sectional view showing the main part of the pouch-shaped battery cell of the present invention.

[0052] Figure 4 1 is a block diagram showing a manufacturing process of an embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0053] Figure 5 is a block diagram showing a manufacturing process of a second embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0054] Figure 6 is a block diagram showing a manufacturing process of a third embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0055] Figure 7 is a block diagram showing a manufacturing process of a fourth embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0056] Figure 8 is a block diagram showing a manufacturing process of a fifth embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0057] 10: Electrode assembly 101: Anode plate

[0058] 101a: Anode sheet 102: Separation membrane

[0059] 103: cathode plate 103a: cathode sheet

[0060] 20: Electrode lead 201: Anode lead

[0061] 202: cathode lead 30: sealing film

[0062] 40: Bag-shaped shell S10: Electrode assembly preparation step

[0063] S20: Electrode lead preparation step S201: Friction welding step

[0064] S201a: Material preparation step S201b: First rotation step

[0065] S201c: Joining step S201d: Second rotation step

[0066] S201e: Bead removal step S202: Rolling step

[0067] S202a: First rolling step S202b: Second rolling step

[0068] S203: Cutting step S30: First welding step

[0069] S301: Anode sheet welding step S302: First pressure application step

[0070] S40: Second welding step S401: Cathode sheet welding step

[0071] S402: Second pressure application step S50: Film bonding step

[0072] S60: Packaging step S70: Electrolyte injection step

[0073] S80: Sealing Step DETAILED DESCRIPTION

[0074] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that a person of ordinary skill in the art to which the present invention belongs can easily implement. However, the description of the present invention is only for the embodiments for structural or functional description, and the protection scope of the present invention should not be interpreted as being limited to the embodiments described herein. That is, because the embodiments can be modified in many ways and can have various forms, the protection scope of the present invention should be understood to include equivalents that can realize the technical ideas. In addition, the purpose or effect proposed in the present invention does not mean that a specific embodiment should include all of them or only include these effects, so the scope of the present invention should not be understood to be limited to this.

[0075] The terms described in the present invention should be understood as having the following meanings.

[0076] The terms "first", "second", etc. are used to distinguish one constituent element from other constituent elements, and the scope of protection is not limited by these terms. For example, the first constituent element may be named the second constituent element, and similarly, the second constituent element may be named the first constituent element. It should be understood that when a constituent element is referred to as "connected to" another constituent element, it may not only be directly connected to the other constituent element, but also other constituent elements may exist between them. On the contrary, it should be understood that when a constituent element is referred to as "directly connected to" another constituent element, there are no other constituent elements between them. In addition, other expressions that describe the relationship between constituent elements, that is, "between" and "directly between" or "adjacent to" and "directly adjacent to", etc., should also be interpreted in the same way.

[0077] Unless the context clearly defines otherwise, singular expressions should be understood to include plural expressions, and terms such as "including" or "having" should be understood to specify the existence of listed features, numbers, steps, actions, constituent elements, parts, or combinations thereof, rather than excluding in advance the existence or additional possibilities of one or more other features, numbers, steps, actions, constituent elements, parts, or combinations thereof.

[0078] Unless otherwise defined, all words used in this article have the same meaning as those commonly understood by ordinary technicians in the technical field to which the present invention belongs. Words defined in common dictionaries should be interpreted as having the same meaning as in the context of the relevant technology, and unless clearly defined in the present invention, should not be interpreted as having an idealized or overly formal meaning.

[0079] Figure 1 is a perspective view showing a pouch-shaped battery cell of the present invention, Figure 2 is an exploded perspective view showing a pouch-shaped battery cell of the present invention, Figure 3 is a side sectional view showing a main part of a pouch-shaped battery cell of the present invention, and Figure 4 1 is a block diagram showing a manufacturing process of an embodiment of a method for manufacturing a pouch-shaped battery cell according to the present invention.

[0080] Reference Figures 1 to 4 Provide explanation.

[0081] In order for the electrode lead 20 to be formed of a friction-welded coated metal so as to be able to be laser-welded with an electrode sheet, the pouch-shaped battery cell manufacturing method of the present invention includes an electrode assembly preparation step S10, an electrode lead preparation step S20, a first welding step S30, a second welding step S40, a film bonding step S50, a packaging step S60, an electrolyte injection step S70, and a sealing step S80.

[0082] The electrode assembly preparation step S10 prepares the electrode assembly 10 composed of the anode plate 101 , the separator 102 , and the cathode plate 103 .

[0083] The anode plate 101 is formed with an anode sheet 101a protruding at one side by punching or slotting, the cathode plate 103 is formed with a cathode sheet 103a protruding at one side by punching or slotting, and a separation membrane 102 is interposed between the anode plate 101 and the cathode plate 103 to form an electrode assembly 10, wherein the electrode assembly 10 is repeatedly stacked in a stacked or folded structure according to the output voltage or charge and discharge capacity required in the battery cell.

[0084] At this time, preferably, the anode plate 101 is formed as an aluminum thin plate having a thickness of 10 μm, and the cathode plate 103 is formed as a copper thin plate having a thickness of 5 μm, but is not limited thereto.

[0085] The electrode lead preparation step S20 includes a friction welding step S201 , a rolling step S202 , and a cutting step S203 .

[0086] In order to friction weld the copper bar and the aluminum bar, the friction welding step S201 includes a material preparation step S201a, a first rotation step S201b and a joining step S201c.

[0087] In the material preparation step S201a, the copper (or copper alloy) rod and the aluminum (or aluminum alloy) rod are respectively mounted on a tray of a friction welding machine.

[0088] In the first rotating step S201b, the copper bar and the aluminum bar mounted on the friction welding machine are rotated in opposite directions at a rotation speed of 1600 to 2200 rpm.

[0089] In the joining step S201c, while the opposing surfaces of the copper rod and the aluminum rod rotating in opposite directions are brought into close contact, a pressure of 7 to 20 tons is applied in a direction toward the contact surface for a predetermined time to join the copper rod and the aluminum rod.

[0090] That is, during the period in which the copper rod and the aluminum rod are rotated at high speeds while applying pressure, friction heat of 400 to 700° C. is generated on the contact surfaces.

[0091] At this time, the friction heat may be different depending on the size of the contact surface of the copper rod and the aluminum rod being contacted.

[0092] Accordingly, when the temperature required for joining the copper rod and the aluminum rod is reached, after stopping the rotation of the copper rod and the aluminum rod, when a pressure of 7 to 20 tons is applied in the direction toward the contact surface for a predetermined time, the copper rod and the aluminum rod are joined according to frictional heat and pressure and form a clad metal joined as a whole by a dual metal.

[0093] In the rolling step S202 , the joint body of the copper bar and the aluminum bar that are friction welded is put into a rolling mill to be processed into a thin plate shape.

[0094] At this time, it should be understood that the rolling mill preferably uses a roller rolling mill in which a plurality of rollers are arranged at predetermined intervals, but is not limited thereto.

[0095] It should be understood that the joint body is rolled by a rolling mill, and the joint body may be rolled in the length direction or in the width direction, and the thickness of the rolled thin plate is preferably formed to be 0.05 to 50 mm, but is not limited thereto.

[0096] In the cutting step S203 , the electrode lead 20 is cut to a size such that copper and aluminum are arranged at both ends of the joint body rolled into a thin plate shape.

[0097] At this time, it should be understood that the cut bonded body may be cut so that the copper portion and the aluminum portion are arranged front and back, or may be cut so that the copper portion and the aluminum portion are arranged left and right when viewed on a plane.

[0098] In the first welding step S30, the anode sheet 101a and one end of the anode lead 201 made of clad metal are laser welded.

[0099] That is, in order to weld one end of the anode lead 201 made of coated metal to the anode sheet 101a, after first supplying the aluminum portion of the anode lead 201 tightly to one side of the anode sheet 101a, the anode sheet 101a made of aluminum and the aluminum portion of the anode lead 201 are laser welded.

[0100] At this time, it should be understood that anode sheet 101a and anode lead 201 are preferably arranged to overlap each other, but are not limited thereto, and laser welding may be configured to cause the end of anode sheet 101a and the end of anode lead 201 to abut against each other.

[0101] In addition, since laser welding has high energy density, the plurality of anode sheets 101 a stacked in multiple layers are welded tightly and firmly to the anode lead 201 , thereby maintaining interspaced bonding and having excellent durability against physical impact.

[0102] In the second welding step S40, the cathode sheet 103a and one end of the cathode lead 202 made of clad metal are laser welded.

[0103] That is, in order to weld one end of the cathode lead 202 made of coated metal to the cathode sheet 103a, after first supplying the copper portion of the cathode lead 202 in close contact with one side of the cathode sheet 103a, the cathode sheet 103a made of copper and the copper portion of the cathode lead 202 are laser welded.

[0104] At this time, it should be understood that cathode sheet 103a and cathode lead 202 are preferably arranged to overlap each other, but are not limited thereto, and laser welding may be configured to cause the end of anode sheet 101a and the end of cathode lead 202 to abut against each other.

[0105] In the film bonding step S50 , the sealing film 30 is bonded to the anode lead 201 and the cathode lead 202 , respectively.

[0106] At this time, it should be understood that the sealing film 30 is preferably bonded by pressure-welding the sealing films 30 respectively surrounding the anode lead 201 and the cathode lead 202 and tightly adhering to each other after the sealing films 30 are supplied in the upper and lower directions of the anode lead 201 and the cathode lead 202, but it is not limited to this.

[0107] In addition, the bonding position of the sealing film is preferably such that the sealing film 30 is bonded to completely surround the material joint of the anode lead 201 and the cathode lead 202 made of the clad metal.

[0108] Therefore, each joint portion of the anode lead 201 and the cathode lead 202 made of the clad metal reacts with the aluminum layer in the bag-like case 40 and causes electrical shock such as a short circuit or physical damage such as corrosion due to interaction.

[0109] In the packaging step S60, after the first bag film 401 constituting the bag shell is formed into a predetermined shape so that the electrode assembly 10 can be placed inside, the electrode assembly 10 is placed on the formed first bag film 401, and the second bag film 402 is also supplied thereto to be welded along the edges of the first bag film 401 and the second bag film 402, thereby storing the electrode assembly 10 inside the bag shell 40.

[0110] At this time, the second bag-like film 402 can also be formed into a predetermined shape symmetrical to the first bag-like film 401 .

[0111] In addition, when the first bag film 401 and the second bag film 402 are welded, the outer ends of the anode lead 201 and the cathode lead 202 are preferably formed to protrude toward one side of the welded bag case 40 .

[0112] At this time, the sealing film 30 respectively adhered to the anode lead 201 and the cathode lead 202 is welded in a state between the first bag film 401 and the second bag film 402 which are welded to each other, thereby not only preventing direct contact with the bag-shaped shell 40 made of aluminum laminate material of the anode terminal and the cathode terminal while preventing the occurrence of physical damage such as electrical shock or corrosion such as short circuit, but also making the seal tighter by the sealing film 30 made of synthetic vertical.

[0113] In addition, for the injection of the electrolyte, it is preferable that an opening is formed at one side edge of the bag-shaped case 40 formed by welding the first bag-shaped film 401 and the second bag-shaped film 402, and the edge is not welded.

[0114] In the electrolyte injection step S70 , the electrolyte is injected into the opening of the bag case 40 formed in the step of packaging the electrode assembly 10 in the bag case 40 .

[0115] In the sealing step S80, the opening of the bag-shaped shell 40 injected with the electrolyte is welded and sealed so that all edge portions of the bag-shaped shell 40 are completely sealed, thereby fixing the electrode assembly 10 housed inside the bag-shaped shell 40 while preventing liquid leakage of the electrolyte injected into the bag-shaped shell 40.

[0116] Figure 5 is a block diagram illustrating a manufacturing process of a second embodiment of a pouch-shaped battery cell and a method for manufacturing the same according to the present invention.

[0117] Will refer to Figure 5 Description will be made, and detailed description of configurations overlapping with the above-described embodiment and configurations having the same reference numerals will be omitted.

[0118] The friction welding step S201 may further include a second rotating step S201d and a bead removing step S201e.

[0119] In the second rotating step S201d, the joint body formed by joining the copper bar and the aluminum bar is rotated in one direction at a rotation speed of 1600 to 2200 rpm.

[0120] In the bead removal step S201e, the bead removal blade is moved toward the other side of the joint body while being brought into close contact with the outer peripheral surface of one side of the rotating joint body, thereby performing turning processing against the outer peripheral surface of the joint body, thereby removing the weld beads of the joint portion formed on the outer peripheral surface of the joint body protruding outward.

[0121] Figure 6 is a block diagram illustrating a manufacturing process of a third embodiment of a pouch-shaped battery cell and a method for manufacturing the same according to the present invention.

[0122] Will refer to Figure 6 Description will be made, and detailed description of configurations overlapping with the above-described embodiment and configurations having the same reference numerals will be omitted.

[0123] The rolling step S202 may include a first rolling step S202a and a second rolling step S202b.

[0124] In the first rolling step S202a, the joint body of the copper bar and the aluminum bar that are friction welded is put into a rolling mill to be rolled into a thin plate of a uniform predetermined thickness.

[0125] In the second rolling step S202b, the copper portion of the thin plate after the first rolling step is rolled to be thinner than the aluminum portion.

[0126] That is, since copper has higher conductivity than aluminum, for the electrode lead 20 made of clad metal, the copper portion and the aluminum portion may have the same conductivity even if the thickness of the copper portion is thinner than that of the aluminum portion.

[0127] Therefore, the amount of copper used, which is heavier than aluminum, can be reduced, and the electrode lead 20 can be made lighter than the electrode lead 20 .

[0128] Figure 7 is a block diagram illustrating a manufacturing process of a fourth embodiment of a pouch-shaped battery cell and a method for manufacturing the same according to the present invention.

[0129] Will refer to Figure 7 Description will be made, and detailed description of configurations overlapping with the above-described embodiment and configurations having the same reference numerals will be omitted.

[0130] The first welding step S30 may further include an anode sheet welding step S301.

[0131] In the anode sheet welding step S301, ultrasonic welding is performed along the edges of the multiple anode sheets 101a stacked in multiple layers, so as to prevent separation between the individual anode sheets 101a constituting the multiple anode sheets 101a stacked in multiple layers. Thus, when laser welding is performed on the close-fitting portions of the anode sheet 101a and the anode lead 201 in the first welding step S30, poor welding of the multiple anode sheets 101a stacked in multiple layers can be prevented.

[0132] The first welding step S30 may further include a first pressurizing step S302 .

[0133] In the first pressure applying step S302, pressure is applied in the vertical direction while the upper and lower surfaces of the plurality of anode sheets 101a stacked in multiple layers are clamped, thereby minimizing the intervals between the individual anode sheets 101a constituting the plurality of anode sheets 101a stacked in multiple layers, thereby preventing the plurality of anode sheets 101a stacked in multiple layers from being poorly welded when laser welding is performed on the close-fitting portions of the anode sheet 101a and the anode lead 201 in the first welding step S30.

[0134] Figure 8 is a block diagram illustrating a manufacturing process of a fifth embodiment of a pouch-shaped battery cell and a method for manufacturing the same according to the present invention.

[0135] Will refer to Figure 8 Description will be made, and detailed description of configurations overlapping with the above-described embodiment and configurations having the same reference numerals will be omitted.

[0136] The second welding step S40 may further include a cathode sheet welding step S401.

[0137] In the cathode sheet welding step S401, ultrasonic welding is performed along the edges of the plurality of cathode sheets 103a stacked in multiple layers, thereby preventing separation between the individual cathode sheets 103a constituting the plurality of cathode sheets 103a stacked in multiple layers. Thus, when laser welding is performed on the close-fitting portions of the cathode sheet 103a and the cathode lead 202 in the second welding step S40, poor welding of the plurality of cathode sheets 103a stacked in multiple layers can be prevented.

[0138] The second welding step S40 may further include a second pressurizing step S402 .

[0139] In the second pressure applying step S402, pressure is applied in the vertical direction while the upper and lower surfaces of the plurality of cathode sheets 103a stacked in multiple layers are clamped, thereby minimizing the intervals between the individual cathode sheets 103a constituting the plurality of cathode sheets 103a stacked in multiple layers, thereby preventing the plurality of cathode sheets 103a stacked in multiple layers from being poorly welded when laser welding is performed on the close-fitting portions of the cathode sheets 103a and the cathode lead 202 in the second welding step S40.

[0140] In the above, the embodiments of the present invention are not only realized by the above-mentioned devices and / or application methods, but can also be realized by a program for realizing the functions corresponding to the configuration of the embodiments of the present invention, a recording medium recording the program, etc., and a technician in the field to which the present invention belongs can easily realize it from the records of the embodiments described above.

[0141] In addition, although the embodiments of the present invention have been described in detail, the scope of protection of the present invention is not limited thereto, and various modifications and improvements made by technicians in the field of the present invention using the basic concepts of the present invention defined in the accompanying claims also fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a pouch-shaped battery cell, comprising the following steps: An electrode assembly preparation step (S10) of preparing an electrode assembly consisting of an anode plate (101), a separation membrane (102) and a cathode plate (103); An electrode lead preparation step (S20) is to prepare electrode leads, namely, an anode lead (201) and a cathode lead (202), which are made of clad metal and are in the shape of thin plates and have copper and aluminum parts at both ends, respectively, to be welded to an anode sheet (101a) formed on the anode plate (101) and a cathode sheet (103a) formed on the cathode plate (103); A first welding step (S30) of laser welding an anode sheet (101a) and an end portion of an anode lead (201) made of a clad metal, which is an aluminum portion; A second welding step (S40) of laser welding the cathode sheet (103a) and one end portion of the cathode lead (202) made of clad metal, which is a copper portion; A film bonding step (S50), bonding the sealing film (30) to the anode lead (201) and the cathode lead (202) respectively; A packaging step (S60), after the sealing film (30) is bonded, the electrode assembly (10) is stored in a bag-shaped case (40); An electrolyte injection step (S70), injecting the electrolyte into the bag-shaped shell (40) encapsulating the electrode assembly (10); as well as A sealing step (S80) is to seal the bag-shaped shell (40) injected with the electrolyte. Wherein, the electrode lead preparation step (S20) includes the following steps: Friction welding step (S201), installing the copper bar and the aluminum bar on a friction welding machine for welding; a rolling step (S202) of processing the friction welded joint body into a thin plate shape; and The cutting step (S203) is to cut the electrode lead (20) according to the size of the electrode lead (20) in such a way that copper and aluminum are arranged at both ends of the rolled joint body. The rolling step (S202) comprises the following steps: A first rolling step (S202a) is to put the joint body formed by friction welding the copper bar and the aluminum bar into a rolling mill to roll them into a uniform thin plate of a predetermined thickness; and The second rolling step (S202b) is to roll the copper portion of the thin plate that has passed the first rolling step to be thinner than the aluminum portion.

2. The method for manufacturing a pouch-shaped battery cell according to claim 1, wherein: The friction welding step (S201) comprises the following steps: A material preparation step (S201a) of installing the copper bar and the aluminum bar on a tray of a friction welding machine respectively; A first rotating step (S201b) of rotating the copper bar and the aluminum bar mounted on the friction welding machine in opposite directions at a rotation speed of 1600 to 2200 rpm; and The joining step (S201c) is to bring the opposing surfaces of the copper rod and the aluminum rod rotating in opposite directions into close contact, and at the same time apply a pressure of 7 to 20 tons in the direction toward the contact surface for a predetermined time, thereby joining the copper rod and the aluminum rod.

3. The method for manufacturing a pouch-shaped battery cell according to claim 2, wherein: The friction welding step (S201) further includes the following steps: A second rotating step (S201d) of rotating the joint body formed by joining the copper rod and the aluminum rod in one direction; and In the bead removing step (S201e), the bead removing blade is brought into close contact with the outer peripheral surface of one side of the rotating bonded body and is moved to the other side of the bonded body, thereby removing the weld beads at the bonded portion.

4. A pouch-shaped battery cell, wherein: The pouch-shaped battery cell is manufactured by the pouch-shaped battery cell manufacturing method according to any one of claims 1 to 3.

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