Electrode assembly and secondary battery comprising same

Abstract

An electrode assembly according to the present invention comprises: a plurality of stacked electrodes, each comprising an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side of the electrode body as the side from which the first electrode tab extends; and an electrode lead electrically coupled to the electrode tabs, wherein the first electrode tabs and the second electrode tabs of the plurality of electrodes are bent and stacked in different directions to form a first electrode tab stack and a second electrode tab stack, and the electrode lead comprises a first electrode lead contacting the first and second electrode tab stacks and a second electrode lead coupled to the first electrode lead, the second electrode lead comprising an opposing portion facing the first electrode lead and an extension portion extending from the opposing portion in a direction away from the electrodes.

Description

Electrode assembly and secondary battery including the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0175546 filed on November 29, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to an electrode assembly and a secondary battery including the same. More specifically, it relates to an electrode assembly configured to minimize dead space and a secondary battery including the same.

[0005] A secondary battery configured to generate electricity is provided with an electrode assembly housed within a battery case. In this case, the electrode assembly is formed by stacking a plurality of electrodes and a plurality of separators alternately. The electrode may include an electrode body in which an active material directly involved in generating electricity is located, and an electrode tab extending from the electrode body to transfer the generated electricity to the outside.

[0006] Multiple electrode tabs, each comprising multiple electrodes, can be joined together as one by means of welding or the like, and connected to an electrode lead. Accordingly, generated electricity can be transferred from the electrode tab to the electrode lead. The electrode lead is connected to the outside of the secondary battery and can serve as a channel to transmit electricity to components requiring it. In this case, since the electrode tab is not a direct component that generates electricity, the space occupied by the electrode tab is a space occupied by a component that does not generate electricity, and can be referred to as dead space. As secondary batteries are generally placed within confined spaces, space utilization is important. In light of this, reducing dead space can increase the amount of electricity that can be generated per unit space, making it a critical task for space utilization.

[0007] When multiple electrode tabs extend away from the electrode body and are joined together, a problem may arise in which an unnecessarily large amount of dead space is formed. Therefore, it is necessary to resolve this.

[0008] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the contents of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application.

[0009] The present invention has been devised to solve the above problems, and the objective of the present invention is to provide an electrode assembly and a secondary battery that reduce the dead space formed by the electrode tab.

[0010] The technical problems to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0011] An electrode assembly according to one embodiment of the present invention comprises an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side to which the first electrode tab of the electrode body extends. It also comprises electrode leads electrically coupled to electrodes and electrode tabs provided in a plurality and stacked. The first electrode tabs and second electrode tabs of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack. The electrode leads include a first electrode lead provided to contact the first electrode tab stack and the second electrode tab stack, and a second electrode lead coupled to the first electrode lead. The second electrode lead includes an opposing portion facing the first electrode lead and an extension portion extending away from the electrode from the opposing portion.

[0012] The opposing part can be coupled by making surface contact with the first electrode lead.

[0013] The first electrode lead has a plate shape and can overlap with the first electrode tab stack and the second electrode tab stack.

[0014] The first electrode lead can be joined by overlapping with the first electrode tab laminate and the second electrode tab laminate and welding to the first electrode tab laminate and the second electrode tab laminate in the direction in which the first electrode tab laminate and the second electrode tab laminate extend.

[0015] The ends of the first electrode tab laminate and the second electrode tab laminate are bent so as to come into contact with the opposite side facing the electrode body of the first electrode lead.

[0016] It may further include an attachment member that combines the end portions of the first electrode tab laminate and the second electrode tab laminate, the first electrode lead, and the electrode body.

[0017] The attachment members are electrically insulated and provided in pairs corresponding to the first electrode tab laminate and the second electrode tab laminate, respectively, and the second electrode lead can be coupled with the first electrode lead between the pair of attachment members.

[0018] It may further include a lead film coupled to the extension.

[0019] The extension can be positioned at the center with respect to the stacking direction of the electrode body.

[0020] The first electrode lead and the second electrode lead can be formed integrally.

[0021] The opposing portion can be formed by bending the first electrode lead.

[0022] A bending groove may be formed in the first electrode lead at a position adjacent to the opposing part.

[0023] The opposing portion may include a first opposing portion and a second opposing portion that are bent in different directions.

[0024] The first electrode lead includes a first part electrode lead extending from a first opposing portion and a second part electrode lead extending from a second opposing portion and extending in a direction different from that of the first part electrode lead, wherein the area of ​​the first part electrode lead that does not overlap with the first opposing portion is located in the bending direction of the first electrode tab laminate, and the area of ​​the second part electrode lead that does not overlap with the second opposing portion may be located in the bending direction of the second electrode tab laminate.

[0025] A coupling slit may be formed in the opposing portion in the area overlapping with the first electrode lead.

[0026] An electrode assembly according to one embodiment of the present invention comprises an electrode body, an electrode including an electrode tab that is bent and extended from the electrode body, and an electrode lead that is electrically coupled to the electrode tab. The electrode lead comprises a first electrode lead that is arranged to make surface contact with the electrode tab and a second electrode lead that is coupled to the first electrode lead by making surface contact.

[0027] The second electrode lead may include an opposing portion facing the first electrode lead and an extension portion extending away from the electrode from the opposing portion.

[0028] The first electrode lead has a plate shape and can overlap with the first electrode tab stack and the second electrode tab stack.

[0029] A tab coupling slit may be formed in the area of ​​the first electrode lead that overlaps with the electrode tab.

[0030] A secondary battery according to one embodiment of the present invention comprises an electrode assembly and a battery case that accommodates the electrode assembly. The electrode assembly comprises an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side to which the first electrode tab of the electrode body extends. It also comprises electrode leads electrically coupled to electrodes and electrode tabs that are provided in a plurality and stacked. The first electrode tabs and second electrode tabs of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack. The electrode leads comprise a first electrode lead provided to contact the first electrode tab stack and the second electrode tab stack, and a second electrode lead coupled to the first electrode lead. The second electrode lead comprises an opposing portion facing the first electrode lead and an extension portion extending away from the electrode from the opposing portion.

[0031] An electrode assembly according to one embodiment of the present invention can reduce dead space by reducing the degree to which the electrode tab protrudes from the electrode body by bending the electrode tab from the electrode body.

[0032] An electrode assembly according to one embodiment of the present invention includes a first electrode tab and a second electrode tab that are bent in opposite directions on one side, so that even if there is an area where the electrode tabs are excessively overlapped and not welded together in either of the overlapping areas of the first electrode tab and the second electrode tab, welding is performed in the other area, thereby preventing the problem caused by the electrode tabs not being welded.

[0033] An electrode assembly according to one embodiment of the present invention includes an electrode lead having a shape that is coupled to a surface disposed on the outside by bending of an electrode tab and extends in a direction opposite to that of the electrode, thereby providing an electrode lead that is stably coupled to an electrode tab despite the shape of the electrode tab.

[0034] An electrode assembly according to one embodiment of the present invention can be configured so that the electrode leads are stably formed by including a first electrode lead coupled to an electrode tab and a second electrode lead coupled to the first electrode lead.

[0035] A secondary battery according to one embodiment of the present invention can have the above effects by including the above electrode assembly.

[0036] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0037] FIG. 1 is an assembly diagram of a secondary battery according to a first embodiment of the present invention.

[0038] Figure 2 is a cross-sectional view of the secondary battery shown in Figure 1 when completed.

[0039] FIG. 3 is a perspective view showing the electrode tab bent at the electrode of the electrode assembly shown in FIG. 1.

[0040] FIG. 4 is a perspective view illustrating the coupling of a first electrode lead to an electrode tab of the electrode assembly shown in FIG. 3.

[0041] FIG. 5 is a perspective view showing a first electrode lead coupled to an electrode tab of the electrode assembly shown in FIG. 4.

[0042] FIG. 6 is a perspective view showing that the end of the electrode tab of the electrode assembly shown in FIG. 5 is bent, and an attachment member is attached to the bent portion.

[0043] FIG. 7 is a perspective view showing a second electrode lead coupled to a first electrode lead of an electrode assembly shown in FIG. 6.

[0044] FIG. 8 is a perspective view illustrating the electrode lead shown in FIG. 7.

[0045] FIG. 9 is a perspective view illustrating an electrode lead according to a second embodiment of the present invention.

[0046] FIG. 10 is an unfolded view showing the electrode lead shown in FIG. 9 unfolded.

[0047] FIG. 11 is a perspective view illustrating an electrode lead according to a third embodiment of the present invention.

[0048] FIG. 12 is an unfolded view showing the electrode lead shown in FIG. 11 unfolded.

[0049] FIG. 13 is a perspective view illustrating an electrode lead according to a fourth embodiment of the present invention.

[0050] FIG. 14 is an unfolded view showing the electrode lead shown in FIG. 13 unfolded.

[0051] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0052] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0053] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0054] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0055] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0056] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0057] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0058] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components.

[0059] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in other aspects (e.g., importance or order).

[0060] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0061] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0062] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0063] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0064] Meanwhile, terms such as "up-and-down direction," "downward side," and "front-backward direction" used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0065] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0066] First embodiment

[0067] FIG. 1 is an assembly diagram of a secondary battery (B) according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the secondary battery (B) shown in FIG. 1 when completed.

[0068] With reference to FIGS. 1 and 2, a secondary battery (B) according to the first embodiment of the present invention will be described.

[0069] A secondary battery (B) configured to generate electricity may be provided. The secondary battery (B) may be rechargeable and rechargeable, allowing for multiple uses. The secondary battery (B) may include a battery case (10) located on the outside, an electrode assembly (EA) accommodated inside the battery case (10), and an electrolyte configured to be injected into the battery case (10). At this time, as shown in FIG. 1, the battery case (10) may be formed by a pouch film. However, if necessary, the battery case (10) may be provided in a cylindrical or prismatic shape. The electrolyte may generally refer to an electrolyte in a liquid state, but may also refer to an electrolyte in a solid state if necessary.

[0070] A battery case (10) may include a receiving portion (11) in which an electrode receiving space (11S) is formed to accommodate an electrode assembly (EA), and a side portion (12) extending from the receiving portion (11). The receiving portion (11) may be provided in a pair as shown in FIG. 1. When an electrode assembly (EA) is received in one receiving portion (11), the other receiving portion (11) covers the electrode assembly (EA) so that the electrode assembly (EA) can be received in the battery case (10). A pair of receiving portions (11) may be formed in a single battery case (10). However, if necessary, a receiving portion (11) may be formed in each of the distinct pair of battery cases (10). Furthermore, if necessary, a receiving portion (11) may be provided as a single unit.

[0071] The side portion (12) may include a lead sealing portion (12a), a degas sealing portion (12b), and / or a folding portion (12c). The lead sealing portion (12a) may be provided in a pair so as to extend in the Y direction from the receiving portion (11). The degas sealing portion (12b) may be provided in a pair so as to extend in the X direction from the receiving portion (11). The folding portion (12c) may be positioned between the pair of receiving portions (11). As illustrated in FIG. 1, the folding portion (12c) may be folded so that the pair of receiving portions (11) are positioned to face each other. When the pair of receiving portions (11) are positioned to face each other, the folded lead sealing portion (12a) may be positioned to face each other, and the pair of degas sealing portions (12b) may also be positioned to face each other. The opposing lead sealing portion (12a) and degas sealing portion (12b) can be fused together by heat and pressure to seal the receiving portion (11). Furthermore, the degas sealing portion (12b) can be trimmed to a predetermined length to reduce its length and increase the space utilization of the secondary battery (B), and the trimmed degas sealing portion (12b) can be folded again to reduce the space occupied by the degas sealing portion (12b).

[0072] The electrode assembly (EA) may include an electrode (100), a separator (not shown), and / or an electrode lead (EL). The electrode (100) and the separator may be provided in multiple numbers and arranged to be stacked alternately. In this case, the electrode (100) may include an electrode body (110) and an electrode tab (120) extending from the electrode body (110). The electrode tab (120) may be formed to have a width smaller than that of the electrode body (110). An active material may be applied to the electrode body (110) to directly generate electricity. The electrode tab (120) may serve as a passage for moving the electricity generated from the electrode body (110). The electrode tab (120) may be coupled with the electrode lead (EL) to transfer electricity back to the electrode lead (EL). The electrode lead (EL) protrudes outward from the battery case (10), so that an external component requiring electricity can come into contact with the electrode lead (EL) and receive electricity from the secondary battery (B).

[0073] At this time, since the electrode tab (120) is not a part that generates electricity, it may not contribute to the amount of electricity generated per space. Therefore, it is necessary to reduce the dead space (DS), which is the space occupied by the electrode tab (120). To solve this, a secondary battery (B) according to an embodiment of the present invention, as shown in FIG. 2, may be provided.

[0074] As shown in FIG. 2, the electrode tab (120) may be configured to be bent downward from the electrode body (110) rather than extending outward toward the electrode (100), so as to be in close contact with the electrode body (110). However, the bending direction of the electrode tab (120) may be upward rather than downward as needed, and furthermore, may be in a different direction as long as it is not parallel to the extension direction of the electrode body (110). The bent electrode tab (120) may form an electrode tab stack (121). With reference to FIG. 2, one side of the electrode tab stack (121) may be positioned facing to the right, and an electrode lead (EL) may be attached to the one side of the electrode tab stack (121) on the right side of the electrode tab stack (121). Accordingly, the distance from the electrode body (110) to the end of the electrode tab (120) may be shorter than when the electrode tab (120) extends in a direction parallel to the electrode body (110). The space located above and below the electrode tab (120) may form a dead space (DS) which is unnecessary for generating electricity. In particular, as illustrated in FIG. 2, it may be necessary to reduce the dead space distance (DD), which is the distance to the inner wall of the receiving portion (11), in order to reduce the dead space (DS).

[0075] Hereinafter, the electrode assembly (EA) according to the first embodiment of the present invention will be described in more detail. In particular, the electrode assembly (EA) according to the first embodiment of the present invention will be described below focusing on features regarding the electrode tab (120) being bent and the electrode lead (EL) coupled to the bent electrode tab (120). In particular, the following description will focus on the formation process of the electrode assembly (EA) and explain the function of each component in each process.

[0076] FIG. 3 is a perspective view showing an electrode tab (120) bent from an electrode (100) of an electrode assembly (EA) shown in FIG. 1. FIG. 4 is a perspective view showing a first electrode lead (200) coupled to an electrode tab (120) of an electrode assembly (EA) shown in FIG. 3. FIG. 5 is a perspective view showing the first electrode lead (200) coupled to an electrode tab (120) of an electrode assembly (EA) shown in FIG. 4. FIG. 6 is a perspective view showing an end of an electrode tab (120) of an electrode assembly (EA) shown in FIG. 5 bent, and an attachment member (500) attached to the bent portion. FIG. 7 is a perspective view showing a second electrode lead (300) coupled to a first electrode lead (200) of an electrode assembly (EA) shown in FIG. 6. FIG. 8 is a perspective view illustrating the electrode lead (EL) shown in FIG. 7.

[0077] With reference to FIGS. 3 to 8, the configuration of the electrode tab (120) and electrode lead (EL) of the electrode assembly (EA) according to the first embodiment of the present invention will be described.

[0078] As illustrated in FIG. 3, the electrode tab (120) can be folded from the electrode body (110). At this time, each electrode (100) can be stacked with the electrode tab (120) already folded from the electrode body (110). However, if necessary, an electrode (100) including an electrode tab (120) that is not folded from the electrode body (110) can be stacked first, and after stacking, the stacked electrode tab (120) can be folded from the electrode body (110).

[0079] At this time, the electrode tab (120) may include a first electrode tab (120a) extending from the electrode body (110) and a second electrode tab (120b) extending from the same side as the side to which the first electrode tab (120a) of the electrode body (110) extends. Based on FIG. 3, the side of the electrode body (110) to which the first electrode tab (120a) and the second electrode tab (120b) extend may be the front. The first electrode tab (120a) and the second electrode tab (120b) may have the same polarity. For example, if the first electrode tab (120a) is positive, the second electrode tab (120b) may also be positive. Forming the electrode tab (120) having one polarity as a pair of electrode tabs (120) rather than as a single electrode tab (120) may be intended to prevent welding defects described below. Furthermore, by forming a plurality of electrode tabs (120), the resistance received by the electrode tabs (120) while electricity is transmitted through the electrode tabs (120) can be lowered. At this time, the electrode tabs (120) may be provided as a number of electrode tabs (120) greater than a pair, as needed.

[0080] As illustrated in FIG. 3, the first electrode tab (120a) is positioned to the right of the second electrode tab (120b) and can be bent downward, and the second electrode tab (120b) is positioned to the left of the first electrode tab (120a) and can be bent upward. At this time, the electrode tab (120) can be understood as a higher concept that extracts the common features of the first electrode tab (120a) and the second electrode tab (120b). Furthermore, the bending direction of the first electrode tab (120a) only needs to be different from the bending direction of the second electrode tab (120b), and if necessary, the bending direction of the first electrode tab (120a) may be bent in a direction other than upward. Also, the position of the first electrode tab (120a) may be positioned at a location other than to the right of the second electrode tab (120b) if necessary. A first electrode tab (120a) may be stacked in multiple numbers to form a first electrode tab stack (121a), and a second electrode tab (120b) may be stacked in multiple numbers to form a second electrode tab stack (121b). At this time, the electrode tab stack (121) can be understood as a higher concept from which common features of the first electrode tab stack (121a) and the second electrode tab stack (121b) are extracted. At this time, the first electrode tab stack (121a) may be bent so that its lower surface is exposed based on the direction in which it is extended parallel to the extension direction of the electrode body (110) before being bent. The second electrode tab stack (121b) may be bent so that its upper surface is exposed based on the direction in which it is extended parallel to the extension direction of the electrode body (110) before being bent. In other words, the electrode tab stack (121) can be formed by sweeping and folding a plurality of electrode tabs (120) in one direction. Since the degree of protrusion of this electrode tab stack (121) relative to the electrode body (110) is small, the dead space (DS) can be reduced.

[0081] As illustrated in FIGS. 4 and 5, a first electrode lead (200) may be provided to be coupled to a first electrode tab laminate (121a) and a second electrode tab laminate (121b). The electrode lead (EL) described above may be a higher concept that extracts common features of the first electrode lead (200) and the second electrode lead (300). The first electrode lead (200) may be positioned in front of the first electrode tab laminate (121a) and the second electrode (100) tab laminate. Accordingly, the rear surface of the first electrode lead (200) may be coupled to the lower surface of the first electrode tab laminate (121a) before it is folded and the upper surface of the second electrode tab laminate (121b) before it is folded. In other words, the first electrode lead (200) can be joined by overlapping with the first electrode tab laminate (121a) and the second electrode tab laminate (121b) and welding them in the direction in which the first electrode tab laminate (121a) and the second electrode tab laminate (121b) extend. At this time, the first electrode lead (200) may have a plate shape. More specifically, the first electrode lead (200) may have a plate shape and overlap with the first electrode tab laminate (121a) and the second electrode tab laminate (121b). The first electrode lead (200) may not be positioned beyond where the electrode body (110) is laminated. However, if the first electrode lead (200) is combined with the first electrode tab (120a) and the second electrode tab (120b), it may have a shape other than a plate as needed. Furthermore, the first electrode lead (200) may be formed integrally. However, if the first electrode lead (200) is electrically connected to one another, it may be provided as an assembly of multiple components as needed.

[0082] At this time, as shown in the cross-sectional view illustrated in FIG. 4, the degree of overlap of the electrode tabs (120) in the electrode tab stack (121) may vary depending on the position. If we look at the degree of overlap of the electrode tabs (120) in the first tab overlap area (A1) located on the upper side and the second tab overlap area (A2) located on the lower side of the first tab overlap area (A1) based on FIG. 4, the degree of tab overlap in the second tab overlap area (A2) is greater than the degree of tab overlap in the first tab overlap area (A1). At this time, as illustrated in FIG. 5, when welding is performed from the outside of the first electrode lead (200) toward the electrode tab stack (121) to form a welding line (WL), if uniform thermal energy is applied to the welding line (WL), the thermal energy from the welding may be sufficiently transferred to the electrode tab (120) in the first tab overlap area (A1), but may not be sufficiently transferred to the electrode tab (120) closest to the electrode body (110) in the second tab overlap area (A2). Therefore, the electrode tab (120) closest to the electrode body (110) may not be able to be combined with the surrounding electrode tabs (120). To overcome this, the electrode tab (120) may be composed of two electrode tabs, a first electrode tab (120a) and a second electrode tab (120b), and the bending directions of the first electrode tab (120a) and the second electrode tab (120b) may be provided differently from each other.In particular, as shown in FIG. 4, when the bending direction of the second electrode tab (120b) is bent downward, there is a greater overlap of the second electrode tab (120b) in the part located relatively lower than the part located relatively higher of the second electrode tab stack (121b), which poses a risk that welding will not be properly performed. Conversely, since the part located relatively lower of the bent first electrode tab stack (121a) has less overlap than the part located relatively higher, even if welding is not properly performed in the second electrode tab stack (121b), welding is performed in the first electrode tab stack (121a), thereby reducing the possibility of an electrode tab (120) not being welded to the surroundings. Furthermore, additionally, if a single electrode tab (120) is provided, there is a possibility that a bending moment may occur in the direction in which the bend is released, and the first electrode lead (200) coupled with the single electrode tab (120) may rotate in one direction due to the bending moment. However, as in the first embodiment of the present invention, if a first electrode tab (120a) and a second electrode tab (120b) are provided respectively and their bending directions are different, even if a bending moment occurs in the direction in which the bend is released in the first electrode tab stack (121a), the bending moment generated in the direction in which the bend is released in the second electrode tab stack (121b) occurs in the opposite direction, so the bending moments cancel each other out, thereby preventing the first electrode lead (200) from moving. Additionally, the combination of the first electrode lead (200), the first electrode tab laminate (121a), and the second electrode tab laminate (121b) may be done by other methods not by welding as needed.

[0083] Furthermore, as illustrated in FIG. 5, when the first electrode lead (200) is coupled to the first electrode tab stack (121a) and the second electrode tab stack (121b), the end of the first electrode tab stack (121a) may be exposed to the upper side of the first electrode lead (200), and the end of the second electrode tab stack (121b) may be exposed to the upper side of the first electrode lead (200). The exposed end of the first electrode tab stack (121a) may be bent downward to face the outer surface of the first electrode lead (200), and the exposed end of the second electrode tab stack (121b) may be bent upward to face the outer surface of the first electrode lead (200). In other words, the ends of the first electrode tab stack (121a) and the second electrode tab stack (121b) are bent so as to come into contact with the opposite side facing the electrode body (110) of the first electrode lead (200).

[0084] As described above, the bent configuration may generate a bending moment in the direction in which the bend is released. Since the end of the first electrode tab stack (121a) and the end of the second electrode tab stack (121b) may be deformed due to the occurrence of a bending moment in an unintended direction, an attachment member (500) may be provided to prevent this. The attachment member (500) may connect the end of the first electrode tab stack (121a) and the second electrode tab stack (121b), the first electrode lead (200), and the electrode body (110). As shown in FIG. 6, the attachment member (500) may be provided as a pair to cover the end of the first electrode tab stack (121a) and the end of the second electrode tab stack (121b), respectively. The attachment member (500) can be attached to the electrode body (110), the electrode tab laminate (121), and the first electrode lead (200) to fix them to each other. The attachment member (500) may be, for example, a tape. Furthermore, the attachment member (500) may have an electrically insulating material so that electricity can be prevented from flowing through the attachment member (500) between the electrode tab (120), the electrode body (110), and the electrode lead (EL).

[0085] As illustrated in FIGS. 7 and 8, a second electrode lead (300) coupled to a first electrode lead (200) may be provided. The first electrode lead (200) may be coupled to the second electrode lead (300) between a pair of attachment members (500) in order to be electrically connected to the second electrode lead (300). The second electrode lead (300) may be exposed to the outside of the battery case (10) so that an external component can make contact.

[0086] The second electrode lead (300) may include an opposing portion (310) facing the first electrode lead (200) and an extension portion (320) extending from the opposing portion (310) in a direction away from the electrode (100). At this time, the opposing portion (310) may extend in a direction parallel to the extension direction of the first electrode lead (200). Furthermore, the opposing portion (310) may be coupled by surface contact with the first electrode lead (200). Accordingly, the resistance between the opposing portion (310) and the first electrode lead (200) may be reduced compared to when they are coupled by point contact. The extension portion (320) may be bent from the opposing portion (310) and extended forward. However, if the extension portion (320) extends in a direction away from the electrode body (110), it may be extended in a direction other than forward as needed. At this time, the position of the extension portion (320) may be a position corresponding to the center of the stacking direction of the electrode body (110), as shown in FIG. 2. In other words, the height (H) from the end of the receiving portion (11) to the extension portion (320) may be half the distance between a pair of receiving portions (11). Accordingly, a pair of receiving portions (11) may be formed at corresponding depths.

[0087] Additionally, a lead film (400) may be attached to the extension (320). The lead film (400) may have a material that is more compatible with the inside of the battery case (10) than the extension (320). Accordingly, the bonding strength may be stronger when the extension (320) is attached to the battery case (10) through the lead film (400) than when the extension (320) is attached to the battery case (10).

[0088] The first embodiment and other embodiments are described below. Content common to the first embodiment will be omitted as much as possible, and the other embodiments will be described focusing on the differences. In other words, it is obvious that if content not explained in the other embodiments is necessary, it can be supplemented through the content of the first embodiment.

[0089] 2nd embodiment

[0090] FIG. 9 is a perspective view illustrating an electrode lead (EL-1) according to a second embodiment of the present invention. FIG. 10 is an unfolded view illustrating the electrode lead (EL-1) illustrated in FIG. 9 unfolded.

[0091] Referring to FIGS. 9 and 10, an electrode lead (EL-1) according to a second embodiment of the present invention will be described.

[0092] The second embodiment differs from the first embodiment in that the first electrode lead (200-1) and the second electrode lead (300-1) are formed integrally.

[0093] In other words, the first electrode lead (200-1) and the second electrode lead (300-1) can be formed integrally. As shown in FIG. 10, the first electrode lead (200-1) and the second electrode lead (300-1), which are formed integrally, are initially laid out in an unbent state, and then bent to take on a shape similar to the first embodiment described above. At this time, the opposing portion (310-1) can be formed by bending the first electrode lead (200-1). A bending groove (202H-1) can be formed in the first electrode lead (200-1) at a location adjacent to the opposing portion (310-1). The bending groove (202H-1) allows easy identification of the point where the opposing portion (310-1) is bent, and furthermore, facilitates the bending process. More specifically, as the opposing portion (310-1) is bent, the configuration located between the first electrode lead (200-1) and the opposing portion (310-1) is folded. During the folding process, the volume may be pushed out into the folding groove (202H-1). If there is no folding groove (202H-1), it may be difficult to move the volume that is pushed out during folding. Therefore, the folding groove (202H-1) can facilitate folding.

[0094] Additionally, as shown in FIG. 10, the electrode lead (EL-1) in a state before being folded can also be referred to as the electrode lead (EL-1). Thus, it can be seen that the concept of the present invention is applied to the electrode lead (EL-1) in a state before being folded.

[0095] Since the electrode lead (EL-1) according to the second embodiment does not have a joining process between the first electrode lead (200-1) and the second electrode lead (300-1), the process can be configured simply and the possibility of problems occurring during the joining process can be reduced.

[0096] Third embodiment

[0097] FIG. 11 is a perspective view illustrating an electrode lead (EL-2) according to a third embodiment of the present invention. FIG. 12 is an unfolded view illustrating the electrode lead (EL-2) shown in FIG. 11 unfolded.

[0098] Referring to FIGS. 11 and 12, an electrode lead (EL-2) according to a third embodiment of the present invention will be described.

[0099] The third embodiment differs from the second embodiment in that the first electrode lead (200-2) is divided into two parts located in different directions, and the third embodiment has a cut slit (CL-2) formed to divide the opposing part (310-2) and the first electrode lead (200-2) into two parts.

[0100] As illustrated in FIG. 12, the opposing portion (310-2) may include a first opposing portion (310a-2) and a second opposing portion (310b-2) configured to be bent in different directions. The first opposing portion (310a-2) may be bent upward and extended, and the second opposing portion (310b-2) may be bent downward and extended. At this time, the first electrode lead (200-2) may include a first part electrode lead (200a-2) extending from the first opposing portion (310a-2) and a second part electrode lead (200b-2) extending from the second opposing portion (310b-2) and extending in a direction different from that of the first part electrode lead (200a-2). A cutting slit (CL-2) separating the first opposing portion (310a-2) and the first part electrode lead (200a-2) and the second opposing portion (310b-2) and the second part electrode lead (200b-2) may be formed.

[0101] At this time, the first part electrode lead (200a-2) may be bent at the first opposing part (310a-2) and extended downward, and the second part electrode lead (200b-2) may be bent at the second opposing part (310b-2) and extended upward. The first part electrode lead (200a-2) and the second part electrode lead (200b-2) may each include areas that overlap with or do not overlap with the first opposing part (310a-2) and the second opposing part (310b-2), respectively. Based on the first part electrode lead (200a-2), the area overlapping with the first opposing part (310a-2) may be difficult to sufficiently reach the first electrode tab laminate (121a-2) because welding must be performed on the outside of the first opposing part (310a-2). Therefore, regarding the portion that does not overlap with the first opposing portion (310a-2) of the first part electrode lead (200a-2), welding can sufficiently transfer thermal energy for welding to the first electrode tab laminate (121a-2). In the above description, it was explained that welding may become difficult as the amount of overlap of the electrode tab (120-2) increases toward the end of the first electrode tab laminate (121a-2). Considering this, it may be desirable for the portion that does not overlap with the first opposing portion (310a-2) of the first part electrode lead (200a-2) to overlap with the end of the first electrode tab laminate (121a-2). The second part electrode lead (200b-2) corresponds to the description regarding the first part electrode lead (200a-2), so it is omitted. In other words, the first part electrode lead (200a-2) may have an area that does not overlap with the first opposing part (310a-2) located in the bending direction of the first electrode tab laminate (121a-2), and the second part electrode lead (200b-2) may have an area that does not overlap with the second opposing part (310b-2) located in the bending direction of the second electrode tab laminate (121b-2).

[0102] 4th embodiment

[0103] FIG. 13 is a perspective view illustrating an electrode lead (EL-3-3) according to a fourth embodiment of the present invention. FIG. 14 is an unfolded view illustrating the electrode lead (EL-3-3) illustrated in FIG. 13 unfolded.

[0104] Referring to FIGS. 13 to 14, an electrode lead (EL-3) according to a third embodiment of the present invention will be described.

[0105] The fourth embodiment differs from the third embodiment in that a joining slit (311H-3) for welding is formed in the opposing portion (310-3).

[0106] A coupling slit (311H-3) may be formed in the area where the first opposing portion (310a-3) and the second opposing portion (310b-3) overlap with the first electrode lead (200-3). Previously, in the description of the second embodiment, the difficulty of welding in the area where the first opposing portion (310a-3) and the second opposing portion (310b-3) overlap with the first part electrode lead (200a-3) and the second part electrode lead (200b-3) was explained. To solve this, a coupling slit (311H-3) may be formed in the first opposing portion (310a-3) and the second opposing portion (310b-3). The coupling slit (311H-3) may extend in the extension direction of the first opposing portion (310a-3) and the second opposing portion (310b-3). The coupling slits (311H-3) may be provided in multiple numbers and arranged in a direction perpendicular to the extension direction. Furthermore, the coupling slits (311H-3) may extend beyond the first opposing portion (310a-3) and the second opposing portion (310b-3) to the first part electrode lead (200a-3) and the second part electrode lead (200b-3).

[0107] Above, we have examined embodiments in which the concept of the present invention from the first to the fourth embodiment can be applied. The concept of the present invention expressed in the embodiments can be explained as follows.

[0108] The electrode assembly comprises an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side to which the first electrode tab of the electrode body extends; it also comprises electrode leads electrically coupled to electrodes and electrode tabs provided in plurality and stacked, wherein the first electrode tabs and second electrode tabs of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack, and the electrode leads include a first electrode lead provided to contact the first electrode tab stack and the second electrode tab stack, and a second electrode lead coupled to the first electrode lead, and the second electrode lead may include an opposing portion facing the first electrode lead and an extension portion extending away from the electrode from the opposing portion.

[0109] Alternatively, the electrode assembly may include an electrode body, an electrode tab that is bent and extended from the electrode body, and an electrode lead that is electrically coupled to the electrode tab, wherein the electrode lead may include a first electrode lead that is arranged to make surface contact with the electrode tab and a second electrode lead that is coupled to the first electrode lead by making surface contact.

[0110] Alternatively, the secondary battery comprises an electrode assembly and a battery case that accommodates the electrode assembly, wherein the electrode assembly comprises an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side to which the first electrode tab of the electrode body extends, and comprises electrode leads electrically coupled to electrodes and electrode tabs provided in a plurality and stacked, wherein the first electrode tabs and second electrode tabs of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack, and the electrode leads comprise a first electrode lead provided to contact the first electrode tab stack and the second electrode tab stack and a second electrode lead coupled to the first electrode lead, and the second electrode lead may include an opposing portion facing the first electrode lead and an extension portion extending away from the electrode from the opposing portion.

[0111] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, unless explicitly limited in the combination of any embodiment with another, it should be considered that combinations between embodiments are possible. Any combination of any embodiment with another embodiment is deemed to be disclosed herein.

[0112] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0113] [Explanation of the symbol]

[0114] B: Secondary battery

[0115] 10: Battery case

[0116] 11: Reception Department

[0117] 11S: Electrode receiving space

[0118] 12: Side

[0119] 12a: Lead sealing part

[0120] 12b: Degas sealing part

[0121] 12c: Folding part

[0122] EA: Electrode assembly

[0123] 100: Electrode

[0124] 110: Electrode body

[0125] 120: Electrode tab

[0126] 120a: First electrode tab

[0127] 120b: Second electrode tab

[0128] 121: Electrode tab laminate

[0129] 121a: First electrode tab laminate

[0130] 121b: Second electrode tab laminate

[0131] EL: Electrode lead

[0132] 200: First electrode lead

[0133] 200a: First part electrode lead

[0134] 200b: Part 2 electrode lead

[0135] 202H: Bending groove

[0136] 300: Second electrode lead

[0137] 310: Opposite part

[0138] 311H: Connecting slit

[0139] 310a-2, 310a-3: First opposing part

[0140] 310b-2, 310b-3: Second opposing part

[0141] 320: Extension part

[0142] 400: Lead film

[0143] 500: Attachment member

[0144] DS: Dead Space

[0145] DD: Dead Space Distance

[0146] H: Lead height

[0147] WL: Welding line

[0148] CL: Incision slit

[0149] A1: 1st tab nested area

[0150] A2: 2nd tab nested area

Claims

1. An electrode comprising an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side of the electrode body to which the first electrode tab extends, and provided in plurality and stacked; and It includes an electrode lead electrically coupled to the electrode tab, and The first electrode tab and the second electrode tab of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack. The above electrode lead is, A first electrode lead arranged to contact the first electrode tab stack and the second electrode tab stack; and It includes a second electrode lead coupled to the first electrode lead, and The second electrode lead above is, A counter portion facing the first electrode lead; and An electrode assembly comprising an extension portion extending in a direction away from the electrode at the aforementioned opposing portion.

2. In Paragraph 1, The above-mentioned opposing portion is an electrode assembly that is coupled by making surface contact with the first electrode lead.

3. In Paragraph 1, The first electrode lead has a plate shape, and the electrode assembly overlaps with the first electrode tab laminate and the second electrode tab laminate.

4. In Paragraph 1, The first electrode lead is joined to the first electrode tab laminate and the second electrode tab laminate by overlapping with the first electrode tab laminate and welding the first electrode tab laminate and the second electrode tab laminate in a direction in which the first electrode tab laminate and the second electrode tab laminate extend.

5. In Paragraph 1, The ends of the first electrode tab laminate and the second electrode tab laminate are bent to form an electrode assembly that contacts the opposite side of the first electrode lead toward the electrode body.

6. In Paragraph 5, An electrode assembly further comprising an attachment member that combines the end portion of the first electrode tab laminate and the second electrode tab laminate, the first electrode lead, and the electrode body.

7. In Paragraph 6, The above attachment member is electrically insulated and is provided in a pair corresponding to the first electrode tab laminate and the second electrode tab laminate, respectively. The second electrode lead is an electrode assembly coupled with the first electrode lead between a pair of attachment members.

8. In Paragraph 1, An electrode assembly further comprising a lead film coupled to the above extension.

9. In Paragraph 1, The above extension is an electrode assembly located in the center with respect to the stacking direction of the electrode body.

10. In Paragraph 1, The first electrode lead and the second electrode lead are integrally formed as an electrode assembly.

11. In Paragraph 1, The above-mentioned opposing portion is an electrode assembly formed by bending the first electrode lead.

12. In Paragraph 1, The first electrode lead is an electrode assembly in which a bending groove is formed at a position adjacent to the opposing portion.

13. In Paragraph 1, The above-mentioned opposing portion is an electrode assembly comprising a first opposing portion and a second opposing portion that are bent in different directions.

14. In Paragraph 13, The first electrode lead includes a first part electrode lead extending from the first opposing portion and a second part electrode lead extending from the second opposing portion and extending in a direction different from that of the first part electrode lead. The first part electrode lead has a region that does not overlap with the first opposing part located in the bending direction of the first electrode tab laminate, and The above second part electrode lead is an electrode assembly in which a region not overlapping with the second opposing part is located in the bending direction of the second electrode tab laminate.

15. In Paragraph 1, The above-mentioned opposing portion is an electrode assembly in which a coupling slit is formed in an area overlapping with the first electrode lead.

16. An electrode comprising an electrode body, and an electrode tab that is bent and extended from the electrode body; and It includes an electrode lead electrically coupled to the electrode tab, and The above electrode lead is, A first electrode lead arranged to make surface contact with an electrode tab; and An electrode assembly comprising a second electrode lead coupled to the first electrode lead by surface contact.

17. In Paragraph 16, The second electrode lead above is, A counter portion facing the first electrode lead; and An electrode assembly comprising an extension portion extending in a direction away from the electrode at the aforementioned opposing portion.

18. In Paragraph 16, The first electrode lead has a plate shape, and the electrode assembly overlaps with the first electrode tab laminate and the second electrode tab laminate.

19. In Paragraph 16, The first electrode lead is an electrode assembly in which a tab coupling slit is formed in an area overlapping with the electrode tab.

20. Electrode assembly; and It includes a battery case that accommodates the above electrode assembly, The above electrode assembly is, Electrodes comprising an electrode body, a first electrode tab extending from the electrode body, and a second electrode tab extending from the same side as the side to which the first electrode tab of the electrode body extends, and arranged in plurality and stacked; and It includes an electrode lead electrically coupled to the electrode tab, and The first electrode tab and the second electrode tab of the plurality of electrodes are bent in different directions and stacked to form a first electrode tab stack and a second electrode tab stack. The above electrode lead is, A first electrode lead arranged to contact the first electrode tab stack and the second electrode tab stack; and It includes a second electrode lead coupled to the first electrode lead, and The second electrode lead above is, A counter portion facing the first electrode lead; and A secondary battery comprising an extension portion extending in a direction away from the electrode at the above-mentioned opposing portion.

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