Secondary batteries

Abstract

The present invention relates to a secondary battery, and a secondary battery according to one aspect of the present invention may include an electrode; an electrode tab including an extension portion extending outward from the electrode and a tab coupling portion provided on one side in the extension direction of the extension portion; an electrode lead coupled to the tab coupling portion to electrically connect the electrode to the outside; and auxiliary coupling members coupled to the electrode lead and the extension portion, respectively.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2023 - 0127307, filed on September 22, 2023, and all the contents disclosed in the literature of the Korean patent application are included as part of this specification.

[0002] The present invention relates to a secondary battery, and more specifically, to a secondary battery that can be stably connected to an external power source or load.

Background Art

[0003] Recently, with the rapid spread of electronic devices using batteries, such as mobile phones, notebook computers, and electric vehicles, the demand for secondary batteries that are small, lightweight, and relatively high - capacity has been rapidly increasing. In particular, lithium secondary batteries have attracted attention as a driving power source for portable devices because they are lightweight and have a high energy density. Along with this, research and development efforts to improve the performance of lithium secondary batteries are actively underway.

[0004] Generally, a secondary battery includes a plurality of electrodes stacked on each other, a separator interposed between the plurality of electrodes, an electrode lead for connecting the electrodes to an external power source or load, and an electrode tab extended from the electrode and coupled to the electrode lead. At this time, the electrode may be a positive electrode containing a positive electrode active material or a negative electrode containing a negative electrode active material.

[0005] In such a secondary battery, the electrode tab functions to electrically connect the electrode and the electrode lead to each other. However, in conventional secondary batteries, when a predetermined defect or damage occurs in the electrode tab, there is a problem that the electrode connected to the electrode tab cannot participate in the charge - discharge process.

[0006] For example, during the manufacturing process of a secondary battery, electrode tabs may be welded to the electrode leads to connect them, but such a welding process may cause a portion of the electrode tab to break. Such damage to the electrode tab can induce a break in the electrode tab, interfering with the charging and discharging of the battery.

[0007] This has created an urgent need for the development of secondary batteries that can stably connect electrodes to external power sources or loads even if certain defects or damage occur to a portion of the electrode tabs. [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention was devised to solve the aforementioned problems, and the object of the present invention is to provide a secondary battery in which electrodes can be stably connected to an external power source or load.

[0009] The problems that the present invention will address are not limited to those mentioned above, and any other problems not mentioned can be clearly understood by a person of the ordinary skill in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0010] A secondary battery according to one aspect of the present invention may include an electrode; an electrode tab including an extension portion extending outward from the electrode and a tab coupling portion provided on one side in the direction of extension of the extension portion; an electrode lead coupled to the tab coupling portion to electrically connect the electrode to the outside; and auxiliary coupling members coupled to the electrode lead and the extension portion, respectively.

[0011] In this case, the auxiliary connecting member may be made of a conductive material such that the current flowing through the extension bypasses the tab joint and flows to the electrode lead.

[0012] In this case, the device may further include a coupling member for connecting at least one of the electrode tab and the electrode lead to the auxiliary coupling member.

[0013] In this case, the auxiliary connecting member and the connecting member may be configured as a single unit.

[0014] In this case, the coupling layer may further be provided between the auxiliary connecting member and the electrode tab, or between the auxiliary connecting member and the electrode lead.

[0015] In this case, the auxiliary connecting member may have a wire shape.

[0016] In this case, the auxiliary connecting member may include a tab-side connecting portion that is connected to the extension portion; a lead-side connecting portion that is connected to the electrode lead; and a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion, and at least a portion of which is elastically expandable and contractible.

[0017] In this case, the auxiliary connecting member may include a tab-side connecting portion that is connected to the extension portion; a lead-side connecting portion that is connected to the electrode lead; and a connecting portion made of a plate-shaped sheet or film that extends between the tab-side connecting portion and the lead-side connecting portion to connect them.

[0018] In this case, at least one of the tab-side connecting portion and the lead-side connecting portion may have a shape in which at least a part of it is bent relative to the extension portion.

[0019] In this case, the auxiliary connecting member includes a tab-side connecting portion that is connected to the extension portion; a lead-side connecting portion that is connected to the electrode lead; and a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion. In the extension portion, the length from the electrode lead to the tab-side connecting portion may be shorter than the length from the tab-side connecting portion to the electrode lead.

[0020] In this case, the electrodes may be provided in multiple quantities and stacked with a separation membrane in between, the electrode tabs may be provided in multiple quantities corresponding to the multiple electrodes, and the auxiliary connecting member may be coupled to the electrode tab located on the outermost shell of the multiple electrode tabs.

[0021] At this time, the auxiliary connecting member includes a first auxiliary connecting member and a second auxiliary connecting member. The first auxiliary connecting member may be coupled to an electrode tab located on the outermost shell on one side among the plurality of electrode tabs, and the second auxiliary connecting member may be coupled to an electrode tab located on the outermost shell on the other side among the plurality of electrode tabs.

Effects of the Invention

[0022] The secondary battery according to one aspect of the present invention is configured such that an auxiliary connecting member respectively coupled to an electrode tab extended from an electrode and an electrode lead assists the electrode tab to connect the electrode and the electrode lead. Therefore, the electrode can be stably connected to an external power source or load.

[0023] The secondary battery according to one aspect of the present invention is configured such that since the auxiliary connecting member is made of a conductive material and the current flowing through the electrode tab can flow around the portion where the electrode tab and the electrode lead are coupled, even if a defect or damage occurs in a part of the electrode tab, the electrical connection between the electrode and the external power source or load can be maintained.

[0024] The effects of the present invention are not limited to the effects described above, and the effects not mentioned can be clearly understood by those having ordinary knowledge in the technical field to which the present invention pertains from the present specification and the attached drawings.

Brief Description of the Drawings

[0025] [Figure 1] It is a perspective view of a secondary battery according to a first embodiment of the present invention. [Figure 2] It is a vertical cross-sectional view of a secondary battery according to a first embodiment of the present invention. [Figure 3] It is a vertical cross-sectional view of a secondary battery according to a second embodiment of the present invention. [Figure 4] It is a vertical cross-sectional view of a secondary battery according to a third embodiment of the present invention. [Figure 5] It is a vertical cross-sectional view of a secondary battery according to a fourth embodiment of the present invention. [Figure 6] It is a vertical cross-sectional view of a secondary battery according to a fifth embodiment of the present invention. [Figure 7] This is a vertical cross-sectional view of a secondary battery according to a sixth embodiment of the present invention. [Modes for carrying out the invention]

[0026] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention may be embodied in a variety of different forms and is not limited to or restricted by the following embodiments.

[0027] In order to clearly explain the present invention, detailed descriptions of prior art that are not relevant to the description or that may obscure the essence of the invention have been omitted. In this specification, when assigning reference numerals to components in each drawing, the same reference numeral is used throughout the specification for components that are the same or similar.

[0028] Furthermore, the terms and words used in this specification and the claims shall not be interpreted in a manner limited to their ordinary and lexicographical meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors themselves may define the concepts of terms as appropriate in order to best describe their invention.

[0029] Figure 1 is a perspective view of a secondary battery according to a first embodiment of the present invention. Figure 2 is a vertical cross-sectional view of a secondary battery according to a first embodiment of the present invention. In this case, the various components of the secondary battery according to the embodiment of the present invention are schematically shown in the drawings, and the size of the components and the thickness of the lines may be slightly exaggerated for the sake of understanding.

[0030] Figure 1 discloses a secondary battery 1 according to a first embodiment of the present invention. The secondary battery 1 according to the first embodiment of the present invention is a device that can store electrical energy or release stored electrical energy to the outside. For this purpose, the secondary battery 1 according to this embodiment may be electrically connected to an external power source or load.

[0031] For example, the secondary battery 1 according to this embodiment can be charged by connecting it to an external power source. Alternatively, the secondary battery 1 according to this embodiment can be connected to an external load and discharge electrical energy into the external load.

[0032] The components of the secondary battery according to the first embodiment of the present invention will now be described in detail. Referring to Figures 1 and 2, the secondary battery 1 according to the first embodiment of the present invention includes an electrode 10 and an electrode tab 20. The electrode 10 may be a rectangular plate, sheet, or film in which an electrode active material is coated on a thin metal film. However, the shape of the electrode 10 can be appropriately modified as needed.

[0033] In this case, the metal sheet may be a thin sheet made of aluminum (Al) or copper (Cu), and the electrode active material may be, but is not limited to, lithium-cobalt oxide (LCO), lithium-manganese oxide (LMO), nickel-cobalt-manganese (NCM), nickel-cobalt-aluminum (NCA), lithium-iron phosphate (LFP), graphite (C), silicon (Si), etc.

[0034] In this embodiment, the electrodes 10 may be composed of multiple electrodes stacked in the vertical direction. In this case, a separation membrane 12 may be interposed between each of the stacked electrodes 10.

[0035] The separation membrane 12 can ensure the stability of the secondary battery 1 by preventing the electrodes 10, which are stacked on top of each other, from coming into contact with each other. Such a separation membrane 12 may be made of polyethylene, polypropylene, or the like, but is not limited to these materials.

[0036] On the other hand, although the drawings in this specification do not separately show the positive and negative electrodes, some of the stacked electrodes 10 may be negative electrodes and the remaining portion may be positive electrodes. Furthermore, the assembly of the stacked electrodes 10 may have positive and negative electrodes stacked alternately. The material of the thin metal sheet and the type of electrode active material can be appropriately selected according to the polarity of the electrodes 10.

[0037] Furthermore, referring to Figures 1 and 2, an electrode tab 20 may be connected to the edge of the electrode 10 according to the first embodiment of the present invention. In this case, multiple electrode tabs 20 may be provided.

[0038] Multiple electrode tabs 20 may be connected to multiple electrodes 10. Such electrode tabs 20 may be made of the same material as the metal plate of the electrode 10, but are not limited to this.

[0039] In this embodiment, the electrode tab 20 may include an extension portion 22 and a tab coupling portion 24. The extension portion 22 may extend from the edge of the electrode 10 to the outside of the electrode 10. In this case, the extension portions 22 of multiple electrode tabs 20 may converge at a single point at a predetermined distance from the electrode 10 where their extension ends are separated.

[0040] The tab coupling portion 24 of the secondary battery 1 according to the first embodiment of the present invention may be provided at the extension end of the extension portion 22. In this embodiment, the tab coupling portion 24 may be a portion in which a plurality of electrode tabs 20 are electrically coupled to each other, while also being coupled to an electrode lead 30, which will be described later.

[0041] For this purpose, the tab coupling portions 24 of the multiple electrode tabs 20 may be stacked and tightly fitted together in the vertical direction. Furthermore, the tab coupling portions 24 of the multiple electrode tabs 20 may be electrically coupled to each other.

[0042] For example, multiple tab joints 24 may be joined via a welding process. Alternatively, multiple tab joints 24 may be joined using connecting members such as screws, pins, rivets, or adhesives. The method by which the multiple tab joints 24 are joined to each other is not particularly limited, as long as they can be electrically connected.

[0043] On the other hand, the assembly of the multiple electrodes 10 and multiple electrode tabs 20 described above has a structure in which the multiple electrodes 10 are stacked in the vertical direction (stack type), but the assembly may take on various forms such as a winding type or a stack / folding type depending on the embodiment of the secondary battery.

[0044] Furthermore, since the positive electrode and the electrode are not shown separately in the drawings of this specification, the electrode tabs are also not shown separately as positive electrode tabs and negative electrode tabs. However, when the positive electrode and negative electrode are stacked alternately, the positive electrode tabs connected to the positive electrode may be stacked with each other, and the negative electrode tabs connected to the negative electrode may be stacked with each other.

[0045] Referring to Figures 1 and 2, the secondary battery 1 according to the first embodiment of the present invention includes electrode leads 30. In this embodiment, the electrode leads 30 are configured to electrically connect the electrode 10 with an external power source or external load. That is, the electrode leads 30 may be configured to function as an electrode interface.

[0046] In this embodiment, the electrode lead 30 may have a plate or bar shape made of a conductive material. One side of the electrode lead 30 may be electrically coupled to a plurality of tab couplings 24 that are bonded to each other.

[0047] For example, the electrode lead 30 and the multiple tab joints 24 may be joined via a welding process. Alternatively, they may be joined using connecting members such as screws, pins, rivets, or adhesives. The method by which the electrode lead 30 and the multiple tab joints 24 are joined to each other is not particularly limited, as long as they can be electrically connected.

[0048] In this embodiment, the electrode lead 30 may be coupled to the tab coupling portion 24 of the electrode tab 20 located on the outermost shell in the stacking direction (i.e., vertical direction) among the plurality of electrode tabs 20. More specifically, as shown in Figure 2, the electrode lead 30 may be coupled to the tab coupling portion 24 of the electrode tab 20a located on the uppermost side among the plurality of electrode tabs 20. Of course, the electrode lead 30 may also be coupled to the tab coupling portion 24 of the electrode tab 20 located on the lowermost side among the electrode tabs 20.

[0049] On the other hand, damage may occur to the electrode tab 20 during the process of connecting the electrode tab 20 and the electrode lead 30, or after they have been connected. For example, a portion of the electrode tab 20 may tear, causing a break in the wire. This is because a certain force (tension) may be applied to the electrode tab 20 when it is connected to the electrode lead 30.

[0050] Such damage may occur in the portion of the electrode tab 20 extension 22 adjacent to the tab coupling portion 24. This is because the aforementioned portion is closest to the effects of the coupling process between the electrode tab 20 and the electrode lead 30.

[0051] Alternatively, such damage may occur in the electrode tab 20 located in the outermost shell in the stacking direction among the multiple electrode tabs 20. Referring to the drawings, the damage may occur in the uppermost or lowermost electrode tab 20 among the multiple electrode tabs 20 shown in Figure 2. This is because the electrode tab 20 located in the outermost shell is more likely to be subjected to strong force (tension) due to its connection with the electrode lead 30.

[0052] As mentioned above, if the electrode tab 20 is damaged, a problem may occur in which the secondary battery 1 cannot function properly. For example, if such damage occurs, the electrode 10 connected to the electrode tab 20 may not be able to participate in the charging or discharging process.

[0053] To solve these problems, the secondary battery 1 according to the first embodiment of the present invention may include an auxiliary connecting member 40. In this embodiment, the auxiliary connecting member 40 is configured to assist the electrode tab 20 in connecting the electrode 10 and the electrode lead 30.

[0054] Referring to Figures 1 and 2, the auxiliary connecting member 40 of the secondary battery 1 according to the first embodiment of the present invention includes a lead-side connecting portion 42, a tab-side connecting portion 44, and a connecting portion 46. The lead-side connecting portion 42 is a component of the auxiliary connecting member 40 that is coupled to the electrode lead 30. In this embodiment, the lead-side connecting portion 42 may be provided in the shape of a plate, sheet, or film.

[0055] The lead-side coupling portion 42 may be coupled to the electrode lead 30 by a coupling member 50. In this case, the coupling member 50 may consist of coupling screws, coupling pins, rivets, etc.

[0056] Such a coupling member 50 may be made of a conductive material. This allows the lead-side coupling portion 42 and the electrode lead 30 to be electrically connected via the coupling member 50. The effects of this will be described later.

[0057] In this case, the lead-side coupling portion 42 may have a shape in which at least a portion is bent so as to face or touch one surface of the electrode lead 30. This may result in a more stable connection between the lead-side coupling portion 42 and the electrode lead 30.

[0058] The tab-side coupling portion 44 is a component of the auxiliary connecting member 40 that is coupled to the extension portion 22 of the electrode tab 20. In this embodiment, the tab-side coupling portion 44 may be provided in the shape of a plate, sheet, or film. The tab-side coupling portion 44 may be coupled to the extension portion 22 of the electrode tab 20 by the aforementioned coupling member 50.

[0059] In this embodiment, the tab-side coupling portion 44 may be coupled to the extension portion 22 of the electrode tab 20 located on the outermost shell in the stacking direction among the multiple electrode tabs 20. More specifically, as shown in Figure 2, the tab-side coupling portion 44 may be coupled to the extension portion 22 of the electrode tab 20a located on the uppermost side. Of course, the tab-side coupling portion 44 may also be coupled to the electrode tab 20 located on the lowermost side.

[0060] This allows the auxiliary connecting member 40 to effectively assist in connecting the electrode 10 and the electrode lead 30, because the aforementioned damage is most likely to occur at the electrode tab 20 located on the outermost shell. Of course, the tab-side connecting portion 44 may be configured to connect to two or more of the multiple electrode tabs 20.

[0061] In this case, the tab-side coupling portion 44 may have a shape in which at least a portion is bent so as to face or touch one surface of the extension portion 22. This may result in a more stable connection between the tab-side coupling portion 44 and the electrode tab 20.

[0062] In this embodiment, the length from the electrode 10 to the tab-side coupling portion 44, viewed from the extension direction of the extension portion 22, may be shorter than the length from the tab-side coupling portion 44 to the electrode lead 30. In other words, the tab-side coupling portion 44 may be located closer to the electrode 10 than to the electrode lead 30, viewed from the extension direction of the extension portion 22.

[0063] This is because the portion of the connection assisted by the auxiliary connecting member 40 is the section between the tab-side connecting portion 44 and the electrode lead 30 in the extension portion 22. Therefore, the closer the tab-side connecting portion 44 is to the electrode 10, the wider the portion of the connection assisted by the auxiliary connecting member 40 becomes. As a result, the auxiliary connecting member 40 of the secondary battery 1 according to this embodiment can more effectively assist in connecting the electrode 10 and the electrode lead 30.

[0064] Next, a connecting portion 46 may be provided between the tab-side connecting portion 44 and the lead-side connecting portion 42. The connecting portion 46 may connect the tab-side connecting portion 44 and the lead-side connecting portion 42 to each other. In this embodiment, the connecting portion 46 may be composed of a plate-like member, sheet, or film that extends from the lead-side connecting portion 42 to the tab-side connecting portion 44.

[0065] As described above, the auxiliary connecting member 40 according to this embodiment is connected to the extension 22 of the electrode tab 20 and the electrode lead 30, respectively, and can alleviate the load (such as tension) applied to the electrode tab 20. This can assist in the connection between the electrode 10 and the electrode lead 30.

[0066] In this case, the auxiliary connecting member 40 of the secondary battery 1 according to the first embodiment of the present invention may be made of an electrically conductive material. Therefore, the current flowing through the extension 22 of the electrode tab 20 can bypass the tab coupling portion 24 and flow to the electrode lead 30, as indicated by the arrows shown in Figure 2.

[0067] As a result, even if there is an electrical conductivity defect in the extension 22 of the electrode tab 20 located between the tab-side coupling portion 44 and the electrode lead 30, the electrode 10 and the external load or power supply can be electrically connected via the auxiliary connecting member 40 and the electrode lead 30. For example, the defect may be a break in the wire caused by a tear in a portion of the extension 22.

[0068] On the other hand, in the illustrated embodiment, the lead-side coupling portion 42, the tab-side coupling portion 44, and the coupling portion 46 of the auxiliary coupling member 40 are shown to be formed integrally. In this case, being formed integrally means that they are not physically or spatially separated. However, the lead-side coupling portion 42, the tab-side coupling portion 44, and the coupling portion 46 may be provided as separate members and then joined together.

[0069] As described above, in the secondary battery 1 according to the first embodiment of the present invention, the auxiliary connecting member 40 is connected to the electrode tab 20 and the electrode lead 30, respectively, and can assist in connecting the electrode 10 to an external load or power source. In this case, the connection may be an electrical connection, or the connection may be a physical or structural connection.

[0070] Furthermore, the auxiliary connecting member 40 of the secondary battery 1 according to the first embodiment of the present invention can also cover the portion where the electrode tab 20 and the electrode lead 30 are connected, protecting them from external impacts and contamination.

[0071] The following describes a secondary battery according to another embodiment of the present invention, with different drawings. Figure 3 is a vertical cross-sectional view of a secondary battery according to the second embodiment of the present invention. Figure 4 is a vertical cross-sectional view of a secondary battery according to the third embodiment of the present invention. Figure 5 is a vertical cross-sectional view of a secondary battery according to the fourth embodiment of the present invention. Figure 6 is a vertical cross-sectional view of a secondary battery according to the fifth embodiment of the present invention. Figure 7 is a vertical cross-sectional view of a secondary battery according to the sixth embodiment of the present invention. In this case, the same reference numerals as in the illustrated drawings indicate the same components that have the same function.

[0072] Figure 3 discloses a secondary battery 101 according to a second embodiment of the present invention. Referring to Figure 3, the secondary battery 101 according to this embodiment may further include a coupling layer 150 provided between the lead-side coupling portion 42 of the auxiliary connecting member 40 and the electrode lead 30. This may cause the lead-side coupling portion 42 and the electrode lead 30 to be coupled to each other.

[0073] In this embodiment, the bonding layer 150 may consist of an adhesive for attaching the auxiliary connecting member 40 to the electrode lead 30. In this case, the bonding layer 150 may contain an electrically conductive material. This allows the bonding layer 150 to electrically connect the auxiliary connecting member 40 and the electrode lead 30.

[0074] Alternatively, the bonding layer 150 may be formed by a welding process. That is, in this embodiment, the bonding layer 150 may consist of a welding material provided separately, or a material formed by melting a portion of the electrode tab 20 or electrode lead 30. In this case as well, the bonding layer 150 can electrically connect the auxiliary connecting member 40 and the electrode lead 30.

[0075] Although not specifically shown in the illustration, the aforementioned bonding layer may also be provided between the tab-side bonding portion 44 and the extension portion 22 of the electrode tab 20a. Of course, either the tab-side bonding portion 44 or the lead-side bonding portion 42 may be bonded by the aforementioned bonding layer 150, and the other may be bonded by the bonding member 50 (shown in Figure 2) described in the first embodiment.

[0076] Thus, with the coupling layer 150 of the secondary battery 101 according to this embodiment, the auxiliary coupling member 40 can be coupled to the electrode tab 20 and electrode lead 30 in a simple process. Furthermore, since the coupling structure between the auxiliary coupling member 40 and the electrode tab 20 and electrode lead 30 can be simplified, the secondary battery 101 can be configured more compactly.

[0077] Figure 4 discloses a secondary battery 201 according to a third embodiment of the present invention. Referring to Figure 4, the auxiliary connecting member 40 according to this embodiment may include a first auxiliary connecting member 40a and a second auxiliary connecting member 40b.

[0078] In this embodiment, the first auxiliary connecting member 40a can connect the electrode lead 30 to the electrode tab 20a located on the outermost side (i.e., the uppermost side) of the plurality of electrode tabs 20 when viewed from the stacking direction of the electrode 10.

[0079] Furthermore, the second auxiliary connecting member 40b can connect the electrode lead 30 to the electrode tab 20b located on the outermost side (i.e., the bottom side) of the plurality of electrode tabs 20 when viewed from the stacking direction of the electrode 10.

[0080] As a result, the connection between the electrode tabs 20a and 20b, which are located on the outermost shell of the multiple electrode tabs 20 and are prone to defects and damage, and the electrode lead 30 can be assisted by the auxiliary connecting member 40.

[0081] Figure 5 discloses a secondary battery 301 according to a fourth embodiment of the present invention. The auxiliary connecting member 40 of the secondary battery 301 according to this embodiment may have at least a portion of it in the shape of a wire.

[0082] More specifically, in this embodiment, the connecting portion 46 of the auxiliary connecting member 40 may consist of a metal wire connecting the tab-side connecting portion 144 and the lead-side connecting portion 142. Therefore, the connecting portion 46 may have a predetermined degree of flexibility.

[0083] This allows for smoother connection between the electrode 10 and the electrode lead 30 by the auxiliary connecting member 40. Furthermore, the connection tolerance between the auxiliary connecting member 40, the electrode tab 20, and the electrode lead 30 can be eliminated.

[0084] In this embodiment, the tab-side coupling portion 144 may have the shape of a plate, sheet, or film that contacts the extension portion 22 of the electrode tab 20. The lead-side coupling portion 142 may have the shape of a plate, sheet, or film that contacts the electrode lead 30.

[0085] This ensures sufficient contact area between the auxiliary connecting member 40 and the electrode tab 20 and electrode lead 30, and provides ample space for the coupling member 50 to be joined. This allows for a more stable coupling structure. Of course, as shown in the embodiment in Figure 3, a coupling layer may be provided instead of the coupling member 50.

[0086] Figure 6 discloses a secondary battery 401 according to a fifth embodiment of the present invention. Referring to Figure 6, the auxiliary connecting member 240 of the secondary battery 401 according to this embodiment may be provided integrally with the connecting member 250. In this case, being provided integrally may mean that they are not physically or spatially separated.

[0087] In this embodiment, a rivet-shaped connecting member 250 can be connected to the lead-side connecting portion 242 of the auxiliary connecting member 240. Furthermore, a rivet-shaped connecting member 250 can be connected to the tab-side connecting portion 244.

[0088] This allows the auxiliary connecting member 240 to be connected to the electrode tab 20 and electrode lead 30 in a simple process. Furthermore, since the connection structure between the auxiliary connecting member 240 and the electrode tab 20 and electrode lead 30 can be simplified, the secondary battery 401 can be configured more compactly.

[0089] Figure 7 discloses a secondary battery 501 according to a sixth embodiment of the present invention. Referring to Figure 7, the auxiliary connecting member 340 of the secondary battery 501 according to the sixth embodiment of the present invention may be configured so that at least a portion of it is elastically expandable and contractible.

[0090] In this embodiment, the connecting portion 346 of the auxiliary connecting member 340 may have an elastically expandable and contractible structure. For example, the connecting portion 346 may have a coil spring shape. Alternatively, the connecting portion 346 may consist of a metal wire that is bent in a curved or zigzag shape.

[0091] This allows for smoother connection between the electrode 10 and the electrode lead 30 by the auxiliary connecting member 340. Furthermore, the coupling tolerance between the auxiliary connecting member 340, the electrode tab 20, and the electrode lead 30 may be slightly relaxed.

[0092] Although the present invention has been described above, even if limited embodiments and drawings have been provided, the present invention is not limited thereto, and various implementations are possible by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below.

[0093] [Explanation of symbols] 1, 101, 201, 301, 401, 501 secondary battery 10 electrodes 20 electrode tabs 30 electrode leads 40, 140, 240, 340 Auxiliary connecting members 50, 250 connecting members 150 bonding layer

Claims

1. Electrodes and, An electrode tab including an extension portion extending outward from the electrode and a tab coupling portion provided on one side in the extension direction of the extension portion, An electrode lead is coupled to the tab coupling portion to electrically connect the electrode to the outside, A secondary battery comprising auxiliary connecting members connected to the electrode leads and the extensions, respectively.

2. The secondary battery according to claim 1, wherein the auxiliary connecting member is made of a conductive material such that the current flowing through the extension bypasses the tab connecting portion and flows to the electrode lead.

3. The secondary battery according to claim 1, further comprising a coupling member for coupling at least one of the electrode tab and the electrode lead to the auxiliary coupling member.

4. The secondary battery according to claim 3, wherein the auxiliary connecting member and the connecting member are configured as a single unit.

5. The secondary battery according to claim 1, further comprising a bonding layer provided between the auxiliary connecting member and the electrode tab, or between the auxiliary connecting member and the electrode lead.

6. The secondary battery according to claim 1, wherein the auxiliary connecting member has a wire shape.

7. The aforementioned auxiliary connecting member is The tab-side connecting portion is connected to the aforementioned extension portion, The lead-side coupling portion that is coupled to the electrode lead, The secondary battery according to claim 1, comprising a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion, and which at least a portion of which is elastically expandable and contractible.

8. The aforementioned auxiliary connecting member is The tab-side connecting portion is connected to the aforementioned extension portion, The lead-side coupling portion that is coupled to the electrode lead, The secondary battery according to claim 1, comprising a connecting portion made of a plate-shaped sheet or film that extends between the tab-side connecting portion and the lead-side connecting portion.

9. The secondary battery according to claim 8, wherein at least one of the tab-side coupling portion and the lead-side coupling portion has a shape in which at least a part of it is bent relative to the extension portion.

10. The aforementioned auxiliary connecting member is The tab-side connecting portion is connected to the aforementioned extension portion, The lead-side coupling portion that is coupled to the electrode lead, It includes a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion, The secondary battery according to claim 1, wherein in the extension portion, the length from the electrode to the tab-side coupling portion is shorter than the length from the tab-side coupling portion to the electrode lead.

11. The aforementioned electrodes are provided in multiple units and stacked with a separation membrane in between. The electrode tabs are provided in multiples, corresponding to multiple electrodes. The secondary battery according to claim 1, wherein the auxiliary connecting member is coupled to the electrode tab located in the outermost shell among the plurality of electrode tabs.

12. The auxiliary connecting member includes a first auxiliary connecting member and a second auxiliary connecting member. The first auxiliary connecting member is coupled to the electrode tab located on the outermost shell of one of the plurality of electrode tabs. The secondary battery according to claim 11, wherein the second auxiliary connecting member is coupled to the electrode tab located on the outermost shell of the plurality of electrode tabs.

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