Secondary battery and method for manufacturing the same

Abstract

This disclosure relates to a rechargeable secondary battery and a method for manufacturing the same. An embodiment of the secondary battery according to this disclosure may include: a plurality of electrode assemblies, each electrode assembly having a bundle of electrode terminals; insert electrodes inserted between the plurality of electrode assemblies; and a housing accommodating the plurality of electrode assemblies and the insert electrodes.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0002261, filed in Korea on January 5, 2024, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a rechargeable secondary battery and a method for manufacturing the same. Background Technology

[0004] Unlike primary batteries, which cannot be recharged, secondary batteries (rechargeable batteries) are batteries that can be charged and discharged. Small secondary batteries are used in portable electronic devices such as mobile phones, laptops, and camcorders, while medium or large secondary batteries are widely used as power sources for drive motors in hybrid vehicles and other similar applications.

[0005] This type of secondary battery can have an electrode assembly consisting of electrodes and a separator housed within an outer casing. In this case, uncoated portions (electrode tabs) without active material are formed on each electrode of the electrode assembly, and these electrode tabs can be welded together to form a single electrode tab bundle. The electrode tab bundle is connected to electrode leads, and the electrode leads can transfer electrical energy from the electrode assembly to the outside.

[0006] To increase the energy capacity of a secondary battery, it is advantageous to increase the thickness of the electrode assembly housed within the outer casing to generate electrical energy. However, as the electrode assembly becomes thicker, the electrode tabs must also become longer to be welded together to form an electrode tab bundle. Electrode tabs with this increased length present problems: they are prone to tearing from external impacts or breaking during the electrode rolling process. Furthermore, the increased length of the electrode tabs also presents the problem that they cannot withstand the tension and may be damaged during the expansion of the electrode assembly due to the use of the secondary battery. Summary of the Invention

[0007] Technical issues

[0008] This disclosure is conceived to solve problems in the related art, and therefore the object of this disclosure is to provide a secondary battery with increased energy capacity without increasing the length of the electrode terminals, as well as a method for manufacturing the secondary battery.

[0009] Technical solution

[0010] A secondary battery according to an embodiment of the present disclosure may include: a plurality of electrode assemblies, each electrode assembly having a bundle of electrode terminals; an insert electrode inserted between the plurality of electrode assemblies; and a housing accommodating the plurality of electrode assemblies and the insert electrode.

[0011] The secondary battery may also include an electrode terminal bundle connected to each of the multiple electrode assemblies and electrode leads for inserting electrodes.

[0012] An electrode terminal bundle can be an assembly of uncoated portions of electrodes that are soldered together, which is part of an electrode assembly.

[0013] The multiple electrode assemblies may include a first electrode assembly disposed above the insertion electrode; and a second electrode assembly disposed below the insertion electrode.

[0014] The first electrode terminal bundle disposed in the first electrode assembly can be soldered to one side of the electrode lead, and the second electrode terminal bundle disposed in the second electrode assembly can be soldered to the other side of the electrode lead.

[0015] The electrode leads may include: a joint where a first electrode tab bundle and a second electrode tab bundle are joined by welding at the joint; and a protrusion that connects to the joint and protrudes to the outside of the housing.

[0016] The joint can be formed to be thicker than the protrusion.

[0017] The insertion electrode can be soldered together with the first electrode terminal bundle to one side of the electrode lead, or together with the second electrode terminal bundle to the other side of the electrode lead.

[0018] The outermost layer of the electrode assembly can be configured as a diaphragm.

[0019] The inserted electrode, which is inserted between multiple electrode assemblies, can be a positive electrode.

[0020] On the other hand, a method for manufacturing a secondary battery according to another embodiment of the present disclosure may include: a preparation step of preparing a plurality of electrode assemblies and insert electrodes, each electrode assembly having an electrode terminal bundle; an electrode insertion step of inserting the insert electrodes between the plurality of electrode assemblies; a connection step of connecting the electrode terminal bundle of each of the plurality of electrode assemblies and the electrode terminal of the insert electrodes to electrode leads; and an encapsulation step of housing the plurality of electrode assemblies and the insert electrodes in a housing.

[0021] The connection steps may include: a pre-soldering step, in which the electrode terminals of the insert electrode, which is inserted between multiple electrode assemblies, are soldered to adjacent electrode terminal bundles; and a main soldering step, in which the electrode terminal bundles of each of the multiple electrode assemblies and the electrode terminals of the insert electrode are soldered to electrode leads.

[0022] In the pre-welding step, the electrode terminals of the inserted electrode can be welded to the first electrode terminal bundle of the first electrode assembly disposed above it, or to the second electrode terminal bundle of the second electrode assembly disposed below it.

[0023] The main welding step may include welding the electrode tab bundles and electrode tabs of each of the multiple electrode assemblies to the junction of the electrode leads.

[0024] In the main welding step, the first electrode terminal bundle of the first electrode assembly located above the insertion electrode can be welded to one side of the joint, and the second electrode terminal bundle of the second electrode assembly located below the insertion electrode can be welded to the other side of the joint.

[0025] In the electrode insertion step, the insertion electrode, which is inserted between multiple electrode assemblies, can be a positive electrode.

[0026] Beneficial effects

[0027] A secondary battery according to an embodiment of the present disclosure may include: a plurality of electrode assemblies, each electrode assembly having a bundle of electrode terminals; an insert electrode inserted between the plurality of electrode assemblies; and a housing accommodating the plurality of electrode assemblies and the insert electrode. In this configuration, there is an advantageous effect of increasing the total energy capacity of the secondary battery without increasing the length of the electrode terminals included in each electrode assembly. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view used to describe the internal structure of a secondary battery according to an embodiment of the present disclosure.

[0029] Figure 2 This is a view used to describe the state in which the inserted electrode is attached to the upper side of the electrode lead in a secondary battery according to an embodiment of the present disclosure.

[0030] Figure 3 This is a view used to describe the state in which the inserted electrode is attached to the underside of the electrode lead in a secondary battery according to an embodiment of the present disclosure.

[0031] Figure 4 This is a flowchart sequentially illustrating a method for manufacturing a secondary battery according to another embodiment of the present disclosure.

[0032] Figure 5 It is shown in sequence. Figure 4 The flowchart of the connection steps. Detailed Implementation

[0033] Preferred embodiments of the present disclosure will be described in full detail below with reference to the accompanying drawings to enable those skilled in the art to readily implement the disclosure. However, the present disclosure may be embodied in many different forms and is not limited to or construed as described below.

[0034] In order to clearly describe this disclosure, irrelevant or detailed descriptions of related known techniques that may unnecessarily obscure the main points of this disclosure have been omitted, and throughout this disclosure, the same or similar reference numerals are attached to the same or similar elements when attaching reference numerals to elements in each figure.

[0035] Furthermore, it should be understood that the terms or words used in this disclosure and the appended claims should not be construed as limited to their general and dictionary meanings, but rather as being interpreted based on the meanings and concepts corresponding to the technical aspects of this disclosure, in accordance with the principle that the inventors are permitted to properly define terms for the best interpretation.

[0036] In the following description, a secondary battery and a method for manufacturing the same according to the present disclosure will be described with reference to the accompanying drawings.

[0037] Secondary batteries

[0038] Figure 1 This is a cross-sectional view used to describe the internal structure of a secondary battery according to an embodiment of the present disclosure. Figure 2 This is a view used to describe the state in which the inserted electrode is attached to the upper side of the electrode lead in a secondary battery according to an embodiment of the present disclosure. Figure 3 This is a view used to describe the state in which the inserted electrode is attached to the underside of the electrode lead in a secondary battery according to an embodiment of the present disclosure.

[0039] Reference Figures 1 to 3 The secondary battery 10 according to this disclosure may include: a plurality of electrode assemblies 100, 200, each electrode assembly having an electrode tab bundle 130, 230; an insert electrode 300 inserted between the plurality of electrode assemblies 100, 200; and a housing 500 accommodating the plurality of electrode assemblies 100, 200 and the insert electrode 300. In this configuration, the electrode tab bundles 130, 230 are respectively disposed in each of the electrode assemblies 100, 200, such that even when the plurality of electrode assemblies 100, 200 are housed within the housing 500, the length of the electrode tab bundles 130, 230 is not increased.

[0040] Here, electrode assemblies 100 and 200 are assemblies composed of electrodes 110 and 210 and diaphragms 120 and 220 inserted between electrodes 110 and 210, and can have various structures. For example, such as Figures 1 to 3As shown, electrode assemblies 100 and 200 may have a stacked structure in which multiple electrodes 110 and 210 and diaphragms 120 and 220 are stacked alternately.

[0041] In addition, although Figures 1 to 3 As not shown, electrode assemblies 100 and 200 may have a stacked and folded structure in which electrodes 110 and 210 and diaphragms 120 and 220 are stacked and folded, or a wound structure in which the stacked bodies of electrodes 110 and 210 and diaphragms 120 and 220 are wound.

[0042] Meanwhile, the electrodes 110 and 210 included in the electrode assemblies 100 and 200 are either positive or negative electrodes, and the electrode assemblies 100 and 200 can be housed in the housing 500 while immersed in the electrolyte.

[0043] The positive electrode can have a structure in which a mixture of active material, conductive material, adhesive, etc., is coated onto a thin plate made of metal such as aluminum, and the coating can be formed on a portion of the positive electrode. The uncoated portion of the positive electrode on which the coating is not formed can then become a positive electrode terminal piece, and these positive electrode terminals can be welded together to form a positive electrode terminal piece bundle.

[0044] The negative electrode that emits electrons via connected wires can have a structure in which an active material or the like is coated onto a negative electrode substrate formed of a thin metal plate. A coating can then be formed on a portion of the negative electrode, and the uncoated portion of the negative electrode can become a negative electrode tab. These negative electrode tabs can be soldered together to form a negative electrode tab bundle.

[0045] The separators 120 and 220 are thin films of insulating material interposed between the electrodes 110 and 210, and the electrodes 110 and 210 with different polarities can be located on one side and the other side of the separators 120 and 220, respectively. That is, the separators 120 and 220 can prevent direct contact between the positive and negative electrodes. Furthermore, multiple pores with a diameter of less than 1 μm can be formed in the separators 120 and 220, through which positive lithium ions, for example, can pass. The separators 120 and 220 can be made of various materials. For example, synthetic resins such as polyethylene (PE) or polypropylene (PP) can be used for the separators 120 and 220.

[0046] Electrode terminal bundles 130 and 230 can be either the positive terminal bundle or the negative terminal bundle described above. Electrode terminal bundles 130 and 230 are formed for each of the electrode assemblies 100 and 200, and therefore the lengths of the electrode terminal bundles 130 and 230 can remain constant regardless of the number of electrode assemblies 100 and 200 included inside the housing 500.

[0047] Specifically, when only one electrode assembly is housed within the housing 500, the length of the electrode tab bundle of the electrode assembly increases as the thickness of the electrode assembly increases. After folding the electrode tabs (the uncoated portions of the electrodes) that constitute the electrode assembly, the electrode tab bundle is formed by welding, because the thicker the electrode assembly, the longer the folded portion of the electrode tabs.

[0048] Unlike the case where a single electrode assembly is formed relatively thickly, the secondary battery 10 according to this disclosure increases the total energy capacity by including a plurality of separate electrode assemblies 100, 200 with a constant thickness within a housing 500. Here, electrode tab bundles 130, 230 are formed for each of the electrode assemblies 100, 200, such that the folded length of each electrode tab constituting the electrode tab bundle 130, 230 can always remain constant.

[0049] Therefore, the secondary battery 10 according to this disclosure has the advantageous effect of improving the total energy capacity without increasing the length of the electrode terminals. In addition, in the secondary battery 10 according to this disclosure, the length of the electrode terminals constituting the electrode terminal bundles 130, 230 is kept relatively short, which has the advantageous effect of preventing the electrode terminals from being easily torn by external impacts or easily broken during the electrode rolling process.

[0050] Meanwhile, the insertion electrode 300 is an electrode inserted between multiple electrode assemblies 100 and 200, and one side and the other side of the insertion electrode 300 can respectively contact the diaphragms 120 and 220 included in the electrode assemblies 100 and 200. That is to say, the outermost layer of the multiple electrode assemblies 100 and 200 can be configured as diaphragms 120 and 220.

[0051] Furthermore, the insertion electrode 300 is the same electrode plate as the electrodes 110 and 210 included in the electrode assemblies 100 and 200, and can be either a positive or negative electrode. In this case, when the insertion electrode 300 is configured as a positive electrode plate, it has the advantageous effect of further improving the total energy capacity of the secondary battery 10.

[0052] Simultaneously, the electrode tab bundles 130 and 230 and the insertion electrode 300 included in each of the multiple electrode assemblies 100 and 200 can be connected to the electrode lead 400. The electrode tab bundles 130 and 230 and the insertion electrode 300 can be connected to the electrode lead 400 in various ways. For example, the uncoated portion of the electrode of the insertion electrode 300 and the electrode tab bundles 130 and 230 can be soldered to the electrode lead 400.

[0053] The uncoated portion of the electrode of the insertion electrode 300 is the area of ​​the insertion electrode 300 without coating active material, and can be either the positive or negative electrode uncoated portion. The uncoated portion of the electrode of the insertion electrode 300 can be welded to the electrode terminal bundles 130 and 230 while folded to one side or the other side.

[0054] The housing 500 is an outer casing material that houses multiple electrode assemblies 100, 200 and inserted electrodes 300, and the multiple electrode assemblies 100, 200 and inserted electrodes 300 can be housed within the housing 500 while immersed in an electrolyte. The housing 500 can be made of various materials. For example, the housing 500 can be a prismatic housing made of a metal such as aluminum or a material such as resin. Alternatively, the housing 500 can be a soft-pack outer casing material formed of a laminate consisting of an inner resin layer, a metal layer, and an outer resin layer.

[0055] When the casing 500 is a soft-pack outer material, the metal layer can serve as a substrate to maintain mechanical strength and a barrier layer to prevent the penetration of moisture and oxygen. The metal layer can be made of aluminum or an aluminum alloy to improve the strength of the battery casing, in addition to preventing the ingress or leakage of foreign substances such as gas and moisture. Aluminum alloys may include alloy grades such as 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105, which can be used alone or in combination of two or more.

[0056] The outer resin layer coated on the outer surface of the metal layer should have excellent resistance to the external environment to protect the electrode assembly from external influences. Therefore, the outer resin layer is required to have excellent tensile strength and durability relative to its thickness. Materials used for the outer resin layer may include polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin-based resins such as polyethylene and polypropylene, etc.

[0057] The inner resin layer coated on the inner surface of the metal layer can be made of a polyolefin-based resin. For example, materials used for the inner resin layer may include cast polypropylene (CPP), chlorinated polypropylene, polyethylene, ethylene-propylene copolymer, polyethylene-acrylic acid copolymer, and polypropylene-acrylic acid copolymer, etc.

[0058] Meanwhile, the housing 500 can be configured in various ways. For example, the housing 500 can consist of an upper housing 510 and a lower housing 520, and the upper housing 510 and the lower housing 520 can be joined together to form a storage space for accommodating multiple electrode assemblies 100, 200. Here, the upper housing 510 and the lower housing 520 can be joined in various ways. For example, the upper housing 510 and the lower housing 520 can be joined by welding or thermal fusion.

[0059] Meanwhile, the electrode assemblies 100 and 200 may include a first electrode assembly 100 disposed above the insertion electrode 300 and a second electrode assembly 200 disposed below the insertion electrode 300. That is, the secondary battery 10 according to this disclosure may have a two-stage structure with the first electrode assembly 100 and the second electrode assembly 200 stacked and the insertion electrode 300 inserted therebetween.

[0060] Here, the first electrode tab bundle 130 disposed in the first electrode assembly 100 can be soldered to one side of the electrode lead 400, and the second electrode tab bundle 230 disposed in the second electrode assembly 200 can be soldered to the other side of the electrode lead 400. Additionally, the uncoated portion of the electrode of the inserted electrode 300 can be soldered together with the first electrode tab bundle 130 to one side of the electrode lead 400, or together with the second electrode tab bundle 230 to the other side of the electrode lead 400.

[0061] Meanwhile, the electrode lead 400 may include a joint 410 and a protrusion 420. The uncoated portions of the first electrode tab bundle 130, the second electrode tab bundle 230, and the electrode of the inserted electrode 300 are welded together at the joint 410. The protrusion 420 is connected to the joint 410 and protrudes to the outside of the housing 500. Here, the joint 410 may be formed to be thicker than the protrusion 420.

[0062] In other words, the uncoated portions of the first electrode terminal bundle 130, the second electrode terminal bundle 230, and the electrode of the inserted electrode 300 are welded to the thick joint 410, preventing the joint 410 from being damaged even when heat and pressure are applied to it. Therefore, the operator can increase the welding strength between the uncoated portions of the first electrode terminal bundle 130, the second electrode terminal bundle 230, and the electrode of the inserted electrode 300 and the joint 410, thus providing the advantageous effect of preventing separation of the bond between the uncoated portions of the first electrode terminal bundle 130, the second electrode terminal bundle 230, and the electrode of the inserted electrode 300 and the joint 410 even when external impacts or the like are applied to the secondary battery 10.

[0063] Meanwhile, the joint 410 and the protrusion 420 can have various shapes. Specifically, the joint 410 can have a cuboid box shape with rounded corners at the corners, and the protrusion 420 can have a terminal shape that protrudes from one surface of the joint 410 in the outward direction of the housing 500.

[0064] The upper housing 510 and lower housing 520 are joined together by heat fusion or the like to form a sealed internal space, and the terminal-shaped protrusion 420 can pass between the upper housing 510 and the lower housing 520. At this time, the sealing member of the internal space of the sealed housing 500 can be inserted between the upper housing 510, the lower housing 520 and the protrusion 420.

[0065] The uncoated portions of the first electrode terminal bundle 130, the second electrode terminal bundle 230, and the electrodes of the insertion electrode 300 can be joined to the joint 410 in various ways. For example, as... Figure 2 As shown, the uncoated portions of the first electrode terminal bundle 130 and the electrodes of the insertion electrode 300 can be bonded to the upper surface of the joint 410, and the second electrode terminal bundle 230 can be bonded to the lower surface of the joint 410. Additionally, as... Figure 3 As shown, the first electrode terminal bundle 130 can be bonded to the upper surface of the joint portion 410, and the second electrode terminal bundle 230 and the uncoated portion of the electrode of the inserted electrode 300 can be bonded to the lower surface of the joint portion 410.

[0066] Manufacturing method of secondary batteries

[0067] Figure 4 This is a flowchart sequentially illustrating a method for manufacturing a secondary battery according to another embodiment of the present disclosure.

[0068] Reference Figure 4 The method for manufacturing a secondary battery according to the present disclosure may include: a preparation step S100, preparing a plurality of electrode assemblies 100 and 200, each having electrode terminal bundles 130 and 230, and an insertion electrode 300; an electrode insertion step S200, inserting the insertion electrode 300 between the plurality of electrode assemblies 100 and 200; a connection step S300, connecting the electrode terminal bundles 130 and 230 of each of the plurality of electrode assemblies 100 and 200 and the electrode terminals of the insertion electrode 300 to an electrode lead 400; and an encapsulation step S400, housing the plurality of electrode assemblies 100 and 200 and the insertion electrode 300 in a housing 500.

[0069] In this case, the electrode terminal bundles 130 and 230 of the manufactured secondary battery 10 are respectively disposed in each of the electrode assemblies 100 and 200, so that even when the housing 500 includes multiple electrode assemblies 100 and 200, it has the advantageous effect of not increasing the length of the electrode terminal bundles 130 and 230.

[0070] Meanwhile, preparation step S100 is a step of preparing multiple electrode assemblies 100, 200 and insertion electrodes 300, and each of the multiple electrode assemblies 100, 200 may be provided with electrode terminal bundles 130, 230. The insertion electrode 300 is an electrode plate identical to the electrodes 110, 210 included in the electrode assemblies 100, 200, and may be a positive or negative electrode.

[0071] Here, each of the electrode assemblies 100 and 200 forms an electrode tab bundle 130 and 230, respectively, and the length of the electrode tabs that are thus folded and welded to form the electrode tab bundles 130 and 230 can remain constant. Specifically, the uncoated portions (electrode tabs) of the electrodes 110 and 210 included in each electrode assembly 100 and 200 are folded and then welded together to form the electrode tab bundles 130 and 230, and the thickness of the electrode assemblies 100 and 200 is predetermined so that the length of the folded and welded electrode tabs can always remain constant.

[0072] The electrode insertion step S200 is a step of inserting the insertion electrode 300 between the electrode assemblies 100 and 200, which are respectively formed with electrode terminal bundles 130 and 230, and can be a step of increasing the total energy capacity of the secondary battery 10. For example, the electrode insertion step S200 can be a step of forming a stack by vertically stacking the electrode assemblies 100 and 200, which are respectively formed with electrode terminal bundles 130 and 230, and the insertion electrode 300.

[0073] The stack is not formed from a single thick electrode assembly, but rather by merging multiple electrode assemblies 100 and 200, so that the lengths of the electrode terminal bundles 130 and 230 can always remain constant. In other words, according to the secondary battery manufacturing method of this disclosure, a secondary battery 10 with improved total energy capacity can be manufactured without increasing the length of the electrode terminals.

[0074] Meanwhile, in the electrode insertion step S200, the operator can insert the insertion electrode 300, which serves as the positive electrode, between the electrode assemblies 100 and 200. In this case, it has the advantageous effect of further improving the total energy capacity of the secondary battery 10.

[0075] The connection step S300 is the step of connecting the electrode tab bundles 130, 230 and the electrode tabs (uncoated portions of the electrodes) of the insertion electrode 300 to the electrode lead 400, and can be configured in various ways. Here, the electrode tab bundles 130, 230 and the uncoated portions of the electrodes of the insertion electrode 300 can be connected to the electrode lead 400 in various ways. For example, the electrode tab bundles 130, 230 and the uncoated portions of the electrodes of the insertion electrode 300 can be soldered to the electrode lead 400.

[0076] The encapsulation step S400 is a step of encapsulating multiple electrode assemblies 100, 200 and intercalation electrodes 300, and can be configured in various ways. For example, the encapsulation step S400 may be a step of housing a stack consisting of multiple electrode assemblies 100, 200 and intercalation electrodes 300 within a housing 500 consisting of an upper housing 510 and a lower housing 520, and then joining the upper housing 510 and the lower housing 520 by thermal fusion or welding. When the upper housing 510 and the lower housing 520 are joined, the internal space of the housing 500 of the stack can be sealed relative to the outside.

[0077] Figure 5 It is shown in sequence. Figure 4 The flowchart of the connection steps.

[0078] Reference Figure 5 The connection step S300 may include: a pre-soldering step S310, which solders the uncoated portion of the electrode of the inserted electrode 300, which is inserted between multiple electrode assemblies 100 and 200, to adjacent electrode terminal bundles 130 and 230; and a main soldering step S320, which solders the electrode terminal bundles 130 and 230 of each of the multiple electrode assemblies 100 and 200 and the uncoated portion of the electrode of the inserted electrode 300 to the electrode lead 400.

[0079] In the pre-welding step S310, the uncoated portion of the electrode of the insertion electrode 300 can be welded to the first electrode terminal bundle 130 of the first electrode assembly 100 disposed above it, or welded to the second electrode terminal bundle 230 of the second electrode assembly 200 disposed below it.

[0080] Here, the uncoated portion of the electrode of the insertion electrode 300 is the area of ​​the insertion electrode 300 without coating of active material, and can be either the positive or negative electrode uncoated portion. In the pre-welding step S310, the uncoated portion of the electrode of the insertion electrode 300 can be welded to the electrode terminal bundles 130 and 230 while folded to one side or the other side.

[0081] Specifically, the pre-soldering step S310 can be a step of soldering the uncoated portion of the electrode of the insertion electrode 300 and the first electrode tab bundle 130 while the uncoated portion of the electrode of the insertion electrode 300 is folded to one side. Alternatively, the pre-soldering step S310 can be a step of soldering the uncoated portion of the electrode of the insertion electrode 300 and the second electrode tab bundle 230 while the uncoated portion of the electrode of the insertion electrode 300 is folded to the other side.

[0082] When the uncoated portion of the electrode of the insertion electrode 300 is welded to the first electrode terminal bundle 130 to form a weld body, the weld body can be welded to the upper surface of the electrode lead 400 in the main welding step S320. At this time, the second electrode terminal bundle 230 can be welded to the lower surface of the electrode lead 400.

[0083] When the uncoated portion of the electrode of the insertion electrode 300 is welded to the second electrode terminal bundle 230 to form a weld body, the weld body can be welded to the lower surface of the electrode lead 400 in the main welding step S320. At this time, the first electrode terminal bundle 130 can be welded to the upper surface of the electrode lead 400.

[0084] Meanwhile, the main welding step S320 may be the step of welding the electrode terminal bundles 130, 230 of each of the first electrode assembly 100 and the second electrode assembly 200, as well as the uncoated portion of the electrode of the insertion electrode 300, to the joint portion 410 of the electrode lead 400.

[0085] Specifically, when the uncoated portion of the electrode of the insertion electrode 300 is welded to the first electrode terminal bundle 130 to form a weld body, the weld body can be welded to the upper surface of the joint 410 in the main welding step S320. At this time, the second electrode terminal bundle 230 can be welded to the lower surface of the joint 410.

[0086] Furthermore, when the uncoated portion of the electrode of the insertion electrode 300 is welded to the second electrode terminal bundle 230 to form a weld body, this weld body can be welded to the lower surface of the joint 410 in the main welding step S320. At this time, the first electrode terminal bundle 130 can be welded to the upper surface of the joint 410.

[0087] Here, the uncoated portions of the first electrode tab bundle 130, the second electrode tab bundle 230, and the electrode of the inserted electrode 300 are welded to one and / or the other surface of the thick joint 410, so that the joint 410 is prevented from being damaged even when heat and pressure are applied to it. Therefore, the operator can increase the welding strength between the uncoated portions of the first electrode tab bundle 130, the second electrode tab bundle 230, and the electrode of the inserted electrode 300 and the joint 410, thus providing the advantageous effect of preventing separation of the bond between the uncoated portions of the first electrode tab bundle 130, the second electrode tab bundle 230, and the electrode of the inserted electrode 300 and the joint 410 even when external impacts or the like are applied to the secondary battery 10.

[0088] Meanwhile, when the upper housing 510 and the lower housing 520 are joined by thermal fusion or welding in the encapsulation step S400, a protrusion 420 formed by protruding from one surface of the joint 410 can be inserted between the upper housing 510 and the lower housing 520. At this time, the sealing member of the internal space of the sealing housing 500 can be inserted between the upper housing 510, the lower housing 520 and the protrusion 420.

[0089] The present disclosure has been described above with respect to a limited number of embodiments and accompanying drawings, but the present disclosure is not limited thereto, and those skilled in the art can implement the present disclosure in various forms within the scope of the technical concept of the present disclosure and the appended claims and their equivalents.

[0090] [Explanation of reference numerals in the attached figures]

[0091] 10: Secondary batteries

[0092] 100, 200: Electrode assemblies

[0093] 110, 210: Electrodes

[0094] 120, 220: Diaphragm

[0095] 130, 230: Electrode terminal bundle

[0096] 300: Insertion of electrodes

[0097] 400: Electrode lead

[0098] 410: Joint

[0099] 420: Protrusion

[0100] 500: Housing

[0101] 510: Upper casing

[0102] 520: Lower housing

Claims

1. A secondary battery, comprising: Multiple electrode assemblies, each electrode assembly having a bundle of electrode terminals; Insert electrodes, which are inserted between the plurality of electrode assemblies; as well as The housing accommodates the plurality of electrode assemblies and the inserted electrodes.

2. The secondary battery according to claim 1, further comprising: Electrode leads connected to the electrode terminal bundle of each of the plurality of electrode assemblies and the electrode terminal of the inserted electrode.

3. The secondary battery according to claim 2, wherein The electrode terminal bundle is an assembly in which the uncoated portions of the electrodes included in the electrode assembly are soldered together.

4. The secondary battery according to claim 2, wherein The plurality of electrode assemblies include: A first electrode assembly disposed above the inserted electrode; and The second electrode assembly is disposed below the inserted electrode.

5. The secondary battery according to claim 4, wherein The first electrode terminal bundle disposed in the first electrode assembly is soldered to one side of the electrode lead, and The second electrode terminal bundle, which is disposed in the second electrode assembly, is welded to the other side of the electrode lead.

6. The secondary battery according to claim 5, wherein The electrode leads include: The first electrode terminal bundle and the second electrode terminal bundle are joined together by welding at the joint; and A protrusion that connects to the joint and protrudes to the outside of the housing.

7. The secondary battery according to claim 6, wherein The joint is formed to be thicker than the protrusion.

8. The secondary battery according to claim 5, wherein The insertion electrode is welded together with the first electrode terminal bundle to one side of the electrode lead, or together with the second electrode terminal bundle to the other side of the electrode lead.

9. The secondary battery according to claim 1, wherein The outermost layer of the electrode assembly is configured as a diaphragm.

10. The secondary battery according to claim 1, wherein The inserted electrode, which is inserted between the plurality of electrode assemblies, is a positive electrode.

11. A method for manufacturing a secondary battery, comprising: Preparation steps: Prepare multiple electrode assemblies and insertion electrodes, each electrode assembly having an electrode terminal bundle; The electrode insertion step involves inserting the insertion electrode between the plurality of electrode assemblies; The connection step involves connecting the electrode terminal bundle of each of the plurality of electrode assemblies and the electrode terminal of the inserted electrode to the electrode lead. as well as The encapsulation step involves housing the plurality of electrode assemblies and the inserted electrodes within a housing.

12. The method for manufacturing a secondary battery according to claim 11, wherein The connection steps include: The pre-welding step involves welding the electrode terminals of the inserted electrodes, which are interposed between the plurality of electrode assemblies, to adjacent electrode terminal bundles; and The main welding step involves welding the electrode terminal bundle of each of the plurality of electrode assemblies and the electrode terminal of the inserted electrode to the electrode lead.

13. The method for manufacturing a secondary battery according to claim 12, wherein In the pre-welding step, The electrode terminals of the inserted electrode are soldered to the first electrode terminal bundle of the first electrode assembly disposed above it, or to the second electrode terminal bundle of the second electrode assembly disposed below it.

14. The method for manufacturing a secondary battery according to claim 12, wherein The main welding steps include: The step of welding the electrode terminal bundle of each of the plurality of electrode assemblies and the electrode terminal of the inserted electrode to the junction of the electrode lead.

15. The method for manufacturing a secondary battery according to claim 14, wherein In the main welding step, The first electrode terminal bundle of the first electrode assembly positioned above the insertion electrode is welded to one side of the joint, and The second electrode terminal bundle of the second electrode assembly located below the insertion electrode is welded to the other side of the joint.

16. The method for manufacturing a secondary battery according to claim 11, wherein In the electrode insertion step, the inserted electrode, which is inserted between the plurality of electrode assemblies, is a positive electrode.

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