Secondary battery

Abstract

The present invention relates to a secondary battery. The secondary battery according to one aspect of the present invention comprises: an electrode; an electrode tab including an extension part that extends outward from the electrode and a tab coupling part that is provided at one side of the extension part in the extension direction; an electrode lead coupled to the tab coupling part so as to electrically connect the electrode to the outside thereof; and an auxiliary connection member coupled to each of the electrode lead and the extension part.

Description

secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0127307, dated September 22, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] 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.

[0005] The recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for compact, lightweight, and relatively high-capacity secondary batteries. In particular, lithium secondary batteries, with their lightweight design and high energy density, are attracting attention as power sources for portable devices. Accordingly, active research and development efforts are underway to improve the performance of lithium secondary batteries.

[0006] Typically, a secondary battery comprises a plurality of electrodes stacked one on top of the other, a separator interposed between each of the plurality of electrodes, an electrode lead for connecting the electrode to an external power source or load, and an electrode tab extending from the electrode and connected to the electrode lead. In this case, the electrode may be a positive electrode including a positive electrode active material or a negative electrode including a negative electrode active material.

[0007] In such secondary batteries, the electrode tabs function to electrically connect the electrodes and electrode leads. However, in conventional secondary batteries, if a defect or damage occurs in the electrode tab, the electrodes connected to the electrode tabs become unable to participate in the charge / discharge process.

[0008] For example, during the manufacturing process of a secondary battery, an electrode tab may be welded to the electrode lead to connect it to the electrode lead. However, this welding process may cause a portion of the electrode tab to be torn. Such damage to the electrode tab may cause a short circuit in the electrode tab, thereby interfering with the charging and discharging of the battery.

[0009] Accordingly, there has been an urgent need for the development of a secondary battery that can stably connect the electrode to an external power source or load even if a certain defect or damage occurs in a portion of the electrode tab of the secondary battery.

[0010] The present invention has been devised to solve the above problems, and the object of the present invention is to provide a secondary battery in which an electrode can be stably connected to an external power source or load.

[0011] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0012] 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 an auxiliary connecting member coupled to the electrode lead and the extension portion, respectively.

[0013] At this time, the auxiliary connecting member may be made of a material having conductivity so that the current flowing through the extension can bypass the tab joint and flow to the electrode lead.

[0014] At this time, a joining member that joins at least one of the electrode tab and the electrode lead to the auxiliary connecting member may be further included.

[0015] At this time, the auxiliary connecting member and the joining member may be formed integrally.

[0016] At this time, a bonding layer may be further included between the auxiliary connecting member and the electrode tab, or between the auxiliary connecting member and the electrode lead.

[0017] At this time, the auxiliary connecting member may have a wire shape.

[0018] At this time, the auxiliary connecting member may include a tab-side connecting portion coupled to the extension portion; a lead-side connecting portion coupled to the electrode lead; and a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion, at least a portion of which can be elastically stretched.

[0019] At this time, the auxiliary connecting member may include a tab-side connecting portion coupled to the extension portion; a lead-side connecting portion coupled to the electrode lead; and a connecting portion made of a plate-shaped sheet or film extending between the tab-side connecting portion and the lead-side connecting portion to connect them.

[0020] At this time, at least one of the tab-side connecting portion and the lead-side connecting portion may have a shape in which at least a portion is bent relative to the extension portion.

[0021] At this time, the auxiliary connecting member includes a tab-side connecting portion connected to the extension portion; a lead-side connecting portion connected to the electrode lead; and a connecting portion connecting the tab-side connecting portion and the lead-side connecting portion, and in the extension portion, a length from the electrode lead to the tab-side connecting portion may be shorter than a length from the tab-side connecting portion to the electrode lead.

[0022] At this time, the electrodes are provided in multiple numbers and are stacked with a separator in between, the electrode tabs are provided in multiple numbers corresponding to the plurality of electrodes, and the auxiliary connecting member can be combined with the electrode tab located at the outermost end among the plurality of electrode tabs.

[0023] At this time, the auxiliary connecting member includes a first auxiliary connecting member and a second auxiliary connecting member, and the first auxiliary connecting member is coupled with an electrode tab located at the outermost side of one of the plurality of electrode tabs, and the second auxiliary connecting member can be coupled with an electrode tab located at the outermost side of the other of the plurality of electrode tabs.

[0024] A secondary battery according to one aspect of the present invention is configured such that an electrode tab extending from an electrode and an auxiliary connecting member respectively connected to an electrode lead assist the electrode tab to connect the electrode and the electrode lead, so that the electrode can be stably connected to an external power source or load.

[0025] In a secondary battery according to one aspect of the present invention, since the auxiliary connecting member is made of a conductive material, current flowing through the electrode tab can bypass the portion where the electrode tab and the electrode lead are connected, so that even if a defect or damage occurs in a portion of the electrode tab, electrical connection between the electrode and an external power source or load can be maintained.

[0026] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0027] Figure 1 is a perspective view of a secondary battery according to a first embodiment of the present invention.

[0028] Figure 2 is a vertical cross-sectional view of a secondary battery according to the first embodiment of the present invention.

[0029] Figure 3 is a vertical cross-sectional view of a secondary battery according to a second embodiment of the present invention.

[0030] Figure 4 is a vertical cross-sectional view of a secondary battery according to a third embodiment of the present invention.

[0031] Figure 5 is a vertical cross-sectional view of a secondary battery according to a fourth embodiment of the present invention.

[0032] Figure 6 is a vertical cross-sectional view of a secondary battery according to the fifth embodiment of the present invention.

[0033] Figure 7 is a vertical cross-sectional view of a secondary battery according to the sixth embodiment of the present invention.

[0034] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0035] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0036] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0037] Fig. 1 is a perspective view of a secondary battery according to a first embodiment of the present invention. Fig. 2 is a vertical cross-sectional view of a secondary battery according to a first embodiment of the present invention. In this drawing, each component of the secondary battery according to an embodiment of the present invention is schematically depicted, and the size of the components, line thickness, etc. may be somewhat exaggerated for the sake of convenience of understanding.

[0038] FIG. 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 capable of storing electrical energy or releasing stored electrical energy to the outside. To this end, the secondary battery (1) according to the present embodiment can be electrically connected to an external power source or load.

[0039] For example, the secondary battery (1) according to the present embodiment may be connected to an external power source and charged. Alternatively, the secondary battery (1) according to the present embodiment may be connected to an external load and discharge electric energy to the external load.

[0040] Hereinafter, components of a secondary battery according to a first embodiment of the present invention will be specifically described. Referring to FIGS. 1 and 2, a 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 square plate, sheet, or film in which an electrode active material is applied to a metal thin film. However, the shape of the electrode (10) may be appropriately modified as needed.

[0041] At this time, the metal plate may be a plate made of aluminum (Al) or copper (Cu), and the electrode active material may be 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., but is not limited thereto.

[0042] And, in this embodiment, the electrodes (10) are configured in multiple pieces and can be stacked in the vertical direction. At this time, a separator (12) can be interposed between each of the stacked electrodes (10).

[0043] The separator (12) can perform the function of ensuring the stability of the secondary battery (1) by preventing the electrodes (10) that are laminated with each other from touching each other. Such a separator (12) can be made of polyethylene, polypropylene, etc., but is not limited thereto.

[0044] Meanwhile, although the drawings of this specification do not separately depict the positive and negative electrodes, some of the stacked plurality of electrodes (10) may be negative electrodes and the remaining portions may be positive electrodes. In addition, the assembly in which the plurality of electrodes (10) are stacked may be one in which the positive and negative electrodes are alternately stacked. The material of the aforementioned metal sheet and the type of electrode active material may be appropriately selected depending on the polarity of the electrode (10).

[0045] Referring again to FIGS. 1 and 2, an electrode tab (20) may be connected to the edge side of the electrode (10) according to the first embodiment of the present invention. At this time, a plurality of electrode tabs (20) may be provided.

[0046] In addition, a plurality of electrode tabs (20) can be connected to a plurality of electrodes (10), respectively. These electrode tabs (20) can be made of the same material as the metal plate of the electrode (10), but are not limited thereto.

[0047] 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). At this time, the extension portions (22) of the plurality of electrode tabs (20) may be gathered at a point where the extension direction ends are spaced apart from the electrode (10) by a predetermined distance.

[0048] 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 direction 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) described later.

[0049] To this end, the tab joints (24) of the plurality of electrode tabs (20) can be stacked and pressed against each other in the vertical direction. In addition, the tab joints (24) of the plurality of electrode tabs (20) can be electrically coupled to each other.

[0050] For example, the plurality of tab joints (24) may be joined through a welding process. Alternatively, the plurality of tab joints (24) may be joined using a joining member such as a screw, pin, rivet, or adhesive. The method by which the plurality of tab joints (24) are joined to each other is not particularly limited as long as they can be electrically connected.

[0051] Meanwhile, the assembly of the plurality of electrodes (10) and the plurality of electrode tabs (20) described above has a structure (stack type) in which the plurality of electrodes (10) are stacked in the vertical direction, but the assembly can be formed in various forms such as a roll type, a stack / folding type, etc., depending on the embodiment of the secondary battery.

[0052] In addition, since the anode and the electrode are not depicted separately in the drawings of this specification, the electrode tabs are not depicted separately as anode tabs and cathode tabs. If the anode and cathode are alternately laminated, the anode tabs connected to the anode may be laminated with each other, and the cathode tabs connected to the cathode may be laminated with each other.

[0053] Referring again to FIGS. 1 and 2, the secondary battery (1) according to the first embodiment of the present invention includes an electrode lead (30). In this embodiment, the electrode lead (30) is configured to electrically connect the electrode (10) and an external power source or external load to each other. That is, the electrode lead (30) may be configured to function as an electrode interface.

[0054] 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 coupling portions (24) that are coupled to each other.

[0055] For example, the electrode lead (30) and the plurality of tab joints (24) may be joined through a welding process. Alternatively, they may be joined using a joining member such as a screw, pin, rivet, or adhesive. The method by which the electrode lead (30) and the plurality of tab joints (24) are joined to each other is not particularly limited as long as they can be electrically connected.

[0056] At this time, in the present embodiment, the electrode lead (30) can be coupled with the tab coupling portion (24) of the electrode tab (20) located at the outermost side in the stacking direction (i.e., up-down direction) among the plurality of electrode tabs (20). More specifically, as illustrated in FIG. 2, the electrode lead (30) can be coupled with the tab coupling portion (24) of the electrode tab (20a) located at the uppermost side among the plurality of electrode tabs (20). Of course, the electrode lead (30) may also be coupled with the tab coupling portion (24) of the electrode tab (20) located at the lowermost side among the electrode tabs (20).

[0057] Meanwhile, damage may occur to the electrode tab (20) during the process of combining the electrode tab (20) and the electrode lead (30) or after they are combined. For example, a portion of the electrode tab (20) may be torn, resulting in a short circuit. This is because a certain force (tension) may be applied to the electrode tab (20) as the electrode tab (20) and the electrode lead (30) are combined.

[0058] Such damage may occur in a portion of the extension (22) of the electrode tab (20) adjacent to the tab joint (24). This is because the portion described above is most closely affected by the joining process of the electrode tab (20) and the electrode lead (30).

[0059] Alternatively, such damage may occur in the electrode tab (20) located at the outermost side in the stacking direction among the plurality of electrode tabs (20). Referring to the drawing, the damage may occur in the electrode tab (20) located at the uppermost or lowermost side among the plurality of electrode tabs (20) illustrated in FIG. 2. This is because the electrode tab (20) located at the outermost side is more likely to receive a strong force (tension) due to its connection with the electrode lead (30).

[0060] As previously explained, if damage occurs to the electrode tab (20), a problem may arise in which the secondary battery (1) cannot function normally. For example, if the damage occurs, the electrode (10) connected to the electrode tab (20) may not be able to participate in the charging or discharging process.

[0061] To solve this problem, 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 connect the electrode (10) and the electrode lead (30) by assisting the electrode tab (20).

[0062] Referring to FIGS. 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 member (42), a tab-side connecting member (44), and a connecting member (46). The lead-side connecting member (42) is a component of the auxiliary connecting member (40) that is connected to the electrode lead (30). In the present embodiment, the lead-side connecting member (42) may be provided in the form of a plate, sheet, or film.

[0063] And, the lead side connecting portion (42) can be connected to the electrode lead (30) by a connecting member (50). At this time, the connecting member (50) can be made of a connecting screw, a connecting pin, a rivet, etc.

[0064] This bonding member (50) may be made of a conductive material. As a result, the lead-side bonding portion (42) and the electrode lead (30) can be electrically connected via the bonding member (50). The resulting effects will be described later.

[0065] At this time, the lead-side connecting portion (42) may have a bent shape so that at least one portion can face or come into contact with one side of the electrode lead (30). As a result, the lead-side connecting portion (42) and the electrode lead (30) can be more stably connected.

[0066] The tab-side connecting portion (44) is a component of an auxiliary connecting member (40) that is connected to the extension portion (22) of the electrode tab (20). In the present embodiment, the tab-side connecting portion (44) may be provided in the form of a plate, sheet, or film. In addition, the tab-side connecting portion (44) may be connected to the extension portion (22) of the electrode tab (20) by the aforementioned connecting member (50).

[0067] At this time, in the present embodiment, the tab-side connecting portion (44) can be connected to the extension portion (22) of the electrode tab (20) located at the outermost side in the stacking direction among the plurality of electrode tabs (20). More specifically, as illustrated in FIG. 2, the tab-side connecting portion (44) can be connected to the extension portion (22) of the electrode tab (20a) located at the uppermost side. Of course, the tab-side connecting portion (44) can also be connected to the electrode tab (20) located at the lowermost side.

[0068] Accordingly, the auxiliary connecting member (40) can effectively assist in the connection between the electrode (10) and the electrode lead (30). This is because the damage described above is more likely to occur in the electrode tab (20) located at the outermost side. Of course, the tab-side connecting portion (44) may also be configured to be connected to two or more of the plurality of electrode tabs (20).

[0069] At this time, the tab-side connecting portion (44) may have a bent shape so that at least one portion can face or come into contact with one side of the extension portion (22). Accordingly, the tab-side connecting portion (44) and the electrode tab (20) can be more stably connected.

[0070] And, in this embodiment, when viewed in the extension direction of the extension portion (22), the length from the electrode (10) to the tab-side coupling portion (44) may be shorter than the length from the tab-side coupling portion (44) to the electrode lead (30). In other words, when viewed in the extension direction of the extension portion (22), the tab-side coupling portion (44) may be positioned closer to the electrode (10) than to the electrode lead (30).

[0071] This is because, since the section where the connection is assisted by the auxiliary connecting member (40) is the section between the tab-side connecting member (44) and the electrode lead (30) in the extension (22), the closer the tab-side connecting member (44) is to the electrode (10), the wider the section where the connection is assisted by the auxiliary connecting member (40). Through this, the auxiliary connecting member (40) of the secondary battery (1) according to the present embodiment can more effectively assist the connection between the electrode (10) and the electrode lead (30).

[0072] 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 the present embodiment, the connecting portion (46) may be formed of a plate-shaped member, sheet, film, or the like that extends from the lead-side connecting portion (42) to the tab-side connecting portion (44).

[0073] In this way, the auxiliary connecting member (40) according to the present embodiment is connected to the extension (22) of the electrode tab (20) and the electrode lead (30), respectively, so as to alleviate the load (tension, etc.) applied to the electrode tab (20). Accordingly, the connection between the electrode (10) and the electrode lead (30) can be assisted.

[0074] At this time, the auxiliary connecting member (40) of the secondary battery (1) according to the first embodiment of the present invention may be made of a material having electrical conductivity. Accordingly, the current flowing through the extension portion (22) of the electrode tab (20) may flow to the electrode lead (30) bypassing the tab connecting portion (24), as indicated by the arrow illustrated in FIG. 2.

[0075] Accordingly, even if there is an electrical conductivity defect in the extension portion (22) of the electrode tab (20) located between the tab-side connecting portion (44) and the electrode lead (30), the electrode (10) and the external load or power source can be electrically connected through the auxiliary connecting member (40) and the electrode lead (30). For example, the defect may be a short circuit caused by a portion of the extension portion (22) being torn.

[0076] Meanwhile, in the illustrated embodiment, the lead-side coupling portion (42), the tab-side coupling portion (44), and the connection portion (46) of the auxiliary connection member (40) are illustrated as being formed integrally. In this case, being formed integrally means that they are not physically and spatially separated. However, the lead-side coupling portion (42), the tab-side coupling portion (44), and the connection portion (46) may be provided as separate members and then coupled.

[0077] As described above, the secondary battery (1) according to the first embodiment of the present invention can assist in the connection between the electrode (10) and an external load or power source by having an auxiliary connecting member (40) connected to the electrode tab (20) and the electrode lead (30), respectively. At this time, the connection may be an electrical connection. Alternatively, the connection may be a physical or structural connection.

[0078] Furthermore, the auxiliary connecting member (40) of the secondary battery (1) according to the first embodiment of the present invention may cover the portion where the electrode tab (20) and the electrode lead (30) are joined to protect them from external impact or contamination.

[0079] Hereinafter, secondary batteries according to other embodiments of the present invention will be described with different drawings. Fig. 3 is a vertical cross-sectional view of a secondary battery according to a second embodiment of the present invention. Fig. 4 is a vertical cross-sectional view of a secondary battery according to a third embodiment of the present invention. Fig. 5 is a vertical cross-sectional view of a secondary battery according to a fourth embodiment of the present invention. Fig. 6 is a vertical cross-sectional view of a secondary battery according to a fifth embodiment of the present invention. Fig. 7 is a vertical cross-sectional view of a secondary battery according to a sixth embodiment of the present invention. In this case, the same reference numerals as in the previously illustrated drawings indicate the same members having the same functions.

[0080] FIG. 3 discloses a secondary battery (101) according to a second embodiment of the present invention. Referring to FIG. 3, the secondary battery (101) according to the present embodiment may further include a bonding layer (150) provided between the lead-side bonding portion (42) of the auxiliary connecting member (40) and the electrode lead (30). Accordingly, the lead-side bonding portion (42) and the electrode lead (30) may be bonded to each other.

[0081] In this embodiment, the bonding layer (150) may be formed of an adhesive for attaching the auxiliary connecting member (40) to the electrode lead (30). At this time, the bonding layer (150) may include an electrically conductive material. Through this, the bonding layer (150) may also electrically connect the auxiliary connecting member (40) and the electrode lead (30).

[0082] Alternatively, the bonding layer (150) may be formed by a welding process. That is, in the present embodiment, the bonding layer (150) may be formed of a separately provided welding material, or may be formed of a material formed by melting a portion of the electrode tab (20) or the electrode lead (30). In this case, the bonding layer (150) may also electrically connect the auxiliary connecting member (40) and the electrode lead (30).

[0083] Although not specifically illustrated, 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) (illustrated in FIG. 2) described in the first embodiment.

[0084] In this way, according to the bonding layer (150) of the secondary battery (101) according to the present embodiment, the auxiliary connecting member (40) can be bonded to the electrode tab (20) and the electrode lead (30) through a simple process. In addition, since the bonding structure between the auxiliary connecting member (40) and the electrode tab (20) and the electrode lead (30) can be simplified, the secondary battery (101) can be configured more compactly.

[0085] FIG. 4 discloses a secondary battery (201) according to a third embodiment of the present invention. Referring to FIG. 4, the auxiliary connecting member (40) according to the present embodiment may include a first auxiliary connecting member (40a) and a second auxiliary connecting member (40b).

[0086] In this embodiment, the first auxiliary connecting member (40a) can connect the electrode tab (20a) located on the outermost side (i.e., the uppermost side) of the plurality of electrode tabs (20) when viewed in the stacking direction of the electrode (10) and the electrode lead (30).

[0087] In addition, the second auxiliary connecting member (40b) can connect the electrode tab (20b) located on the outermost side (i.e., the lowermost side) among the plurality of electrode tabs (20) when viewed in the stacking direction of the electrode (10) and the electrode lead (30).

[0088] Accordingly, the connection between the electrode tabs (20a, 20b) located at the outermost end, which are prone to defects or damage among the plurality of electrode tabs (20), and the electrode lead (30) can be assisted by the auxiliary connecting member (40).

[0089] Fig. 5 discloses a secondary battery (301) according to a fourth embodiment of the present invention. At least one portion of the auxiliary connecting member (40) of the secondary battery (301) according to the present embodiment may have a wire shape.

[0090] More specifically, in this embodiment, the connecting portion (46) of the auxiliary connecting member (40) may be formed of a metal wire connecting the tab-side connecting portion (144) and the lead-side connecting portion (142). Accordingly, the connecting portion (46) may have a predetermined degree of flexibility.

[0091] Due to this, the connection between the electrode (10) and the electrode lead (30) by the auxiliary connecting member (40) can be made more smoothly. In addition, the joining tolerance between the auxiliary connecting member (40), the electrode tab (20), and the electrode lead (30) can be resolved.

[0092] In this embodiment, the tab-side connecting portion (144) may have a plate, sheet, or film shape that comes into contact with the extension portion (22) of the electrode tab (20). And, the lead-side connecting portion (142) may have a plate, sheet, or film shape that comes into contact with the electrode lead (30).

[0093] Due to this, the contact area between the auxiliary connecting member (40), the electrode tab (20), and the electrode lead (30) is sufficiently secured, so that sufficient space can be provided for the joining member (50) to be joined. Accordingly, the joining structure can be constructed more stably. Of course, a joining layer may be provided instead of the joining member (50), as in the embodiment illustrated in FIG. 3.

[0094] FIG. 6 discloses a secondary battery (401) according to a fifth embodiment of the present invention. Referring to FIG. 6, the auxiliary connecting member (240) of the secondary battery (401) according to the present embodiment may be provided integrally with the joining member (250). In this case, being provided integrally may mean that they are not physically or spatially separated.

[0095] In this embodiment, a connecting member (250) having a rivet shape may be connected to the lead-side connecting portion (242) of the auxiliary connecting member (240). In addition, a connecting member (250) having a rivet shape may be connected to the tab-side connecting portion (244).

[0096] Accordingly, the auxiliary connecting member (240) can be connected to the electrode tab (20) and the electrode lead (30) in a simpler process. In addition, since the connecting structure between the auxiliary connecting member (240) and the electrode tab (20) and the electrode lead (30) can be simplified, the secondary battery (401) can be configured more compactly.

[0097] Fig. 7 discloses a secondary battery (501) according to a sixth embodiment of the present invention. Referring to Fig. 7, an 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 thereof can be elastically stretched.

[0098] In the present embodiment, the connecting portion (346) of the auxiliary connecting member (340) may have a structure that can be elastically stretched. For example, the connecting portion (346) may have a coil spring shape. Alternatively, the connecting portion (346) may be formed of a metal wire that is bent in a meandering or zigzag shape.

[0099] Due to this, the connection between the electrode (10) and the electrode lead (30) by the auxiliary connecting member (340) can be made more smoothly. In addition, the joining tolerance between the auxiliary connecting member (340), the electrode tab (20), and the electrode lead (30) can be somewhat relaxed.

[0100] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0101] [Explanation of symbols]

[0102] 1, 101, 201, 301, 401, 501: Secondary batteries

[0103] 10: Electrode

[0104] 20: Electrode tab

[0105] 30: Electrode lead

[0106] 40, 140, 240, 340: Auxiliary connecting member

[0107] 50, 250: No joint

[0108] 150: Bonding layer

Claims

1. Electrode; An electrode tab including an extension portion extending outward from the electrode and a tab joint portion provided on one side of the extension portion in the extension direction; An electrode lead that is coupled to the tab joint and can electrically connect the electrode to the outside; and A secondary battery comprising an auxiliary connecting member each connected to the electrode lead and the extension portion.

2. In paragraph 1, A secondary battery, wherein the auxiliary connecting member is made of a conductive material so that current flowing through the extension can bypass the tab joint and flow to the electrode lead.

3. In paragraph 1, A secondary battery further comprising a joining member that joins at least one of the electrode tab and the electrode lead to the auxiliary connecting member.

4. In paragraph 3, A secondary battery in which the auxiliary connecting member and the bonding member are formed as one piece.

5. In paragraph 1, A secondary battery further comprising a bonding layer provided between the auxiliary connecting member and the electrode tab, or provided between the auxiliary connecting member and the electrode lead.

6. In paragraph 1, A secondary battery, wherein the auxiliary connecting member has a wire shape.

7. In paragraph 1, The above auxiliary connecting member is A tab-side connecting portion connected to the above extension portion; A lead-side connecting portion connected to the electrode lead; and A secondary battery comprising a connecting portion that connects the tab-side connecting portion and the lead-side connecting portion, at least a portion of which can be elastically stretched.

8. In paragraph 1, The above auxiliary connecting member is A tab-side connecting portion connected to the above extension portion; A lead-side connecting portion connected to the electrode lead; and A secondary battery comprising a connecting portion made of a plate-shaped sheet or film extending between the tab-side connecting portion and the lead-side connecting portion to connect them.

9. In paragraph 8, A secondary battery, wherein at least one of the tab-side connecting portion and the lead-side connecting portion has a shape in which at least a portion is bent relative to the extension portion.

10. In paragraph 1, The above auxiliary connecting member is A tab-side connecting portion connected to the above extension portion; A lead-side connecting portion connected to the electrode lead; and Includes a connecting portion connecting the tab-side connecting portion and the lead-side connecting portion, A secondary battery, wherein in the above extension, the length from the electrode to the tab-side connecting portion is shorter than the length from the tab-side connecting portion to the electrode lead.

11. In paragraph 1, The above electrodes are provided in multiple pieces and are stacked with a separator between them. The above electrode tabs are provided in multiple numbers corresponding to the plurality of electrodes, A secondary battery, wherein the auxiliary connecting member is coupled to an electrode tab located at the outermost end among the plurality of electrode tabs.

12. In paragraph 11, The above auxiliary connecting member includes a first auxiliary connecting member and a second auxiliary connecting member, The above first auxiliary connecting member is coupled with an electrode tab located at the outermost side of one of the plurality of electrode tabs, A secondary battery, wherein the second auxiliary connecting member is coupled with an electrode tab located at the outermost side of the plurality of electrode tabs.

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