Electrode lead, electrode assembly, and secondary battery comprising same

Abstract

An electrode assembly according to the present invention comprises: a plurality of electrodes comprising electrode tabs and stacked in one direction; and an electrode lead coupled to the electrode tabs, wherein the electrode tabs are bent in the direction in which the plurality of electrodes are stacked, and the electrode lead has coupling slits overlapping the electrode tabs.

Description

Electrode lead, 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. 10-2024-0175545 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 lead, an electrode assembly, and a secondary battery including the same. More specifically, the invention relates to an electrode lead, an electrode assembly, and a secondary battery including the same configured to minimize dead space.

[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] Furthermore, to reduce this dead space, the electrode tab can be bent, and the electrode lead can be attached to the outer surface of the bent electrode tab. However, since the electrode lead and the electrode tab overlap due to the bending, it may be difficult for each electrode tab to be smoothly connected to the electrode lead. Therefore, while devising a structure to reduce the dead space, it is necessary to simultaneously solve the problem of the electrode tab and the electrode lead not being sufficiently connected.

[0009] 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.

[0010] The present invention has been devised to solve the above problems, and the objective of the present invention is to provide an electrode lead, an electrode assembly, and a secondary battery configured to minimize the dead space of the secondary battery.

[0011] Another objective of the present invention is to provide an electrode lead, an electrode assembly, and a secondary battery configured to ensure sufficient coupling with an electrode tab.

[0012] 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.

[0013] An electrode assembly according to one embodiment of the present invention includes an electrode tab, a plurality of electrodes arranged and stacked in one direction, and an electrode lead coupled to the electrode tab, wherein the electrode tab is bent in the direction in which the plurality of electrodes are stacked, and the electrode lead has a coupling slit formed that overlaps with the electrode tab.

[0014] The coupling slit can be extended in the direction in which the electrode tab is bent.

[0015] The electrode lead includes a first electrode lead directly coupled to an electrode tab 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.

[0016] The extension is formed by being bent at the opposing portion, and the first electrode lead may overlap only partially with the opposing portion.

[0017] The first electrode lead and the second electrode lead are formed integrally, and the opposing portion can be formed by bending the first electrode lead.

[0018] The combined slit may include an opposing slit formed on the opposing side.

[0019] The opposing slit can be formed by extending to a part of the extension.

[0020] It further includes a lead film coupled to the extension, and the opposing slit can extend until the position where the lead film is formed with respect to the extension.

[0021] The coupling slit may include a lead slit formed in the first electrode lead.

[0022] The coupling slit further includes an opposing slit formed on the opposite side, and the lead slit can be connected to the opposing slit.

[0023] The coupling slit includes an opposing slit formed on the opposite side, and the lead slit may overlap at least partially with the opposing slit.

[0024] The first electrode lead overlaps only a portion of the electrode tab, and the lead slit may not overlap with the electrode tab.

[0025] The extension is formed by being bent at the opposing portion, the first electrode lead overlaps only partially with the opposing portion, and the lead slit may not extend to a portion that does not overlap with the opposing portion of the first electrode lead.

[0026] The electrode tab may have a folding end that is folded at one end of the first electrode lead and bent toward the opposite side.

[0027] The folding end is welded and joined to the first electrode lead, and the welding direction of the folding end may differ from the extension direction of the joining slit.

[0028] 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 includes an electrode tab, a plurality of electrodes arranged and stacked in one direction, and an electrode lead coupled to the electrode tab. The electrode tab is bent in the direction in which the plurality of electrodes are stacked, and the electrode lead has a coupling slit formed that overlaps with the electrode tab.

[0029] The coupling slit can be extended in the direction in which the electrode tab is bent.

[0030] The electrode lead includes a first electrode lead directly coupled to an electrode tab 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.

[0031] The combined slit may include an opposing slit formed on the opposing side.

[0032] An electrode lead according to one embodiment of the present invention comprises a first electrode lead configured to be directly coupled to an electrode tab and a second electrode lead coupled to the first electrode lead, wherein 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, and the opposing portion has a coupling slit formed therein that overlaps with the electrode tab.

[0033] An electrode assembly according to one embodiment of the present invention includes an electrode tab bent in one direction, thereby reducing the degree of protrusion of the electrode tab and reducing dead space.

[0034] An electrode assembly according to one embodiment of the present invention includes an electrode lead having a coupling slit formed in a portion overlapping with an electrode tab, thereby enabling sufficient coupling between the electrode tab and the electrode lead.

[0035] An electrode assembly according to one embodiment of the present invention enables the folding end and the electrode lead to be joined by folding an electrode tab, which is bent in one direction, in the opposite direction at the end of the electrode lead to form a folding end that overlaps with the electrode lead.

[0036] An electrode assembly according to one embodiment of the present invention can simplify the welding path of the folding end by forming the welding direction to the folding end of the electrode tab in the width direction of the electrode lead.

[0037] A secondary battery according to one embodiment of the present invention can have the above effects by including the above electrode leads.

[0038] An electrode lead according to one embodiment of the present invention can have the above effects by corresponding to an electrode lead included in the electrode assembly described above.

[0039] 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.

[0040] FIG. 1 is an assembly diagram of a secondary battery according to a first embodiment of the present invention.

[0041] FIG. 2 is a perspective view illustrating the process of joining an electrode lead to an electrode tab during the process of forming an electrode assembly shown in FIG. 1.

[0042] FIG. 3 is a perspective view showing the electrode lead illustrated in FIG. 2 viewed from a different angle.

[0043] FIG. 4 is a perspective view illustrating the process in which the electrode lead shown in FIG. 2 comes into contact with the electrode tab and is welded.

[0044] FIG. 5 is a front view showing the state in which the electrode lead illustrated in FIG. 4 is welded to the electrode tab, viewed from the front.

[0045] FIG. 6 is a perspective view showing the end of the electrode tab shown in FIG. 5 folded.

[0046] FIG. 7 is a front view showing the welding of the folding end of the electrode tab shown in FIG. 6.

[0047] Figure 8 is a cross-sectional view of the secondary battery shown in Figure 1.

[0048] FIG. 9 is a perspective view of an electrode lead according to a second embodiment of the present invention.

[0049] FIG. 10 is a perspective view of an electrode lead according to a third embodiment of the present invention.

[0050] FIG. 11 is an assembly diagram of an electrode assembly according to a fourth embodiment of the present invention.

[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 one component from another and do not limit the components in other aspects (130a-1) (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 according to the first embodiment of the present invention.

[0068] Referring to FIG. 1, a secondary battery according to a 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] The following is explained in more detail with reference to the related drawings.

[0075] FIG. 2 is a perspective view illustrating the process of joining an electrode lead (EL) to an electrode tab (120) during the process of forming an electrode assembly (EA) illustrated in FIG. 1. FIG. 3 is a perspective view illustrating the electrode lead (EL) illustrated in FIG. 2 viewed from a different angle. FIG. 4 is a perspective view illustrating the process of the electrode lead (EL) illustrated in FIG. 2 coming into contact with and being welded to the electrode tab (120). FIG. 5 is a front view illustrating the state in which the electrode lead (EL) illustrated in FIG. 4 is welded to the electrode tab (120) viewed from the front. FIG. 6 is a perspective view illustrating the end of the electrode tab (120) illustrated in FIG. 5 folded. FIG. 7 is a front view illustrating the welded end (121) of the electrode tab (120) illustrated in FIG. 6. FIG. 8 is a cross-sectional view of the secondary battery (B) illustrated in FIG. 1.

[0076] Referring to FIGS. 2 to 8, an electrode assembly (EA) according to a first embodiment of the present invention will be described.

[0077] As illustrated in FIG. 2, the electrode tab (120) according to the first embodiment of the present invention may be bent downward relative to the electrode body (110). However, if necessary, the electrode tab (120) may be bent toward a direction other than downward, provided that it is not in a direction parallel to the electrode body (110). In other words, the electrode (100) may be provided in multiple numbers and stacked in an up-and-down direction, and the electrode tab (120) may be bent in particular parallel to the stacking direction of the electrode (100). Before being bent, the electrode tab (120) protrudes forward, and when accommodated in the battery case (10), a large amount of unnecessary dead space (DS) may be formed. By bending the electrode tab (120), the dead space (DS) can be reduced.

[0078] As the electrode tab (120) is bent downward, a new type of electrode lead (EL) can be provided. In particular, as the electrode tab (120) is bent downward, one side may be exposed at the front, and the electrode lead (EL) may be formed to be coupled to the exposed side of the electrode tab (120). In particular, since the electrode lead (EL) is a part that must extend to the outside of the battery case (10) in order to transmit electricity from the electrode tab (120) to the outside of the battery case (10), such considerations may be reflected in the design of the electrode lead (EL).

[0079] The electrode lead (EL) may include a first electrode lead (200) and a second electrode lead (300). Here, the first electrode lead (200) and the second electrode lead (300) may be formed integrally. However, if necessary, the first electrode lead (200) and the second electrode lead (300) may be provided by a method of being combined as separate components. In this manner, the manufacturing process for forming the shapes of the first electrode lead (200) and the second electrode lead (300) may be made easier.

[0080] The first electrode lead (200) may be a part that is directly coupled to the electrode tab (120). As shown in FIG. 2, the first electrode lead (200) may be in the shape of a rectangular flat plate. However, as long as the shape of the first electrode lead (200) is such that it can be coupled to the electrode tab (120), it may have a shape other than a rectangle or a shape other than a flat plate as needed. In this case, the first electrode lead (200) may have a width corresponding to the width of the electrode tab (120). The width and height of the first electrode lead (200) may be determined according to the width of the electrode tab (120), which is determined by the stacking amount of the electrode (100) and the width of the electrode body (110). However, generally, considering that the stacking amount of the electrode (100) does not exceed the width of the electrode body (110), the first electrode lead (200) may be formed such that its width is longer than its height. At this time, based on FIG. 2, the width direction of the first electrode lead (200) can be defined as the left-right direction, and the height direction can be defined as the up-down direction. Accordingly, the first electrode lead (200) can be seen as extending in the up-down direction.

[0081] The second electrode lead (300) may be formed by bending the first electrode lead (200). The second electrode lead (300) may include an opposing portion (310) formed by bending downward from the upper end of the first electrode lead (200) and an extension portion (320) formed by bending forward from the lower end of the opposing portion (310). However, the starting point of the extension of the opposing portion (310) of the second electrode lead (300) may be the lower end of the first electrode lead (200) as needed. In other words, 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).

[0082] At this time, the extension portion (320) may be a part necessary for the electrode lead (EL) to extend to the outside of the battery case (10), and its position may be located in the middle with respect to the thickness direction of the secondary battery (B), as shown in FIG. 8. When the extension portion (320) is located in the middle of the thickness direction of the secondary battery (B), the receiving portion (11) of the battery case (10) of the same shape can be formed on both sides based on the height (H) of the extension portion (320), so that the production of the receiving portion (11) can be made easier. In order for the extension portion (320) of the second electrode lead (300) to be located in the middle of the thickness direction of the secondary battery (B), the second electrode lead (300) extending from the upper side of the first electrode lead (200) may require a part that extends downward. The opposing portion (310) may be a part necessary for setting the appropriate height of the extension portion (320).

[0083] Furthermore, the opposing portion (310) may be positioned parallel to the extension direction of the first electrode lead (200) so as to be positioned as close as possible to the first electrode lead (200). If the distance between the opposing portion (310) and the first electrode lead (200) is too great, the space between them is unnecessarily formed, and thus a dead space (DS) may be formed again. Therefore, the opposing portion (310) can preferably be in contact with the first electrode lead (200). Furthermore, as described below, a laser for welding the electrode tab (120) can be emitted by penetrating the first electrode lead (200) from the outside of the opposing portion (310). If a large space is created between the opposing portion (310) and the first electrode lead (200), the thickness through which the laser penetrates becomes too thick, making it difficult for the laser energy to be sufficiently transmitted to the electrode tab (120). The contact between the opposing portion (310) and the first electrode lead (200) may also be desirable when considering the welding process of the electrode tab (120) described later.

[0084] Furthermore, the first electrode lead (200) may overlap only partially with the opposing portion (310). The opposing portion (310) and the first electrode lead (200) may overlap in the front-rear direction. As illustrated in FIG. 4, the electrode lead (EL) and the electrode tab (120) may be welded by a laser, and the laser for laser welding needs to penetrate both the opposing portion (310) and the first electrode lead (200) in the portion where the opposing portion (310) and the first electrode lead (200) overlap. Since energy is lost from the laser during this process, the energy delivered to the electrode tab (120) may not be sufficient to weld the electrode tab (120). Therefore, it may be necessary for the opposing portion (310) not to overlap with the first electrode lead (200) as much as possible. To this end, the opposing portion (310) may overlap only with the upper part of the first electrode lead (200) as shown in FIG. 2, and not overlap with the lower part. Since the lower part of the first electrode lead (200) does not overlap with the opposing portion (310), the laser reaches the electrode tab (120) by penetrating only the first electrode lead (200) without penetrating the opposing portion (310), so it may be more effective for welding the electrode tab (120).

[0085] At this time, the location where the opposing part (310) is positioned may be the part where the bending begins based on the electrode tab (120). When considering the electrode tab (120) being bent and overlapped, the degree of overlap of the electrode tab (120) is smaller on the upper side compared to the midpoint based on FIG. 2.

[0086] In the upper section, only some of the multiple electrode tabs (120) are involved and overlap, but in the middle section, the electrode tab (120) that is already bent from the upper section and extends to the lower section, and the electrode tab (120) that is bent from the middle section and begins to extend, are involved together, so the degree of overlap can be greater. Therefore, the middle section of the bent multiple electrode tabs (120) may require less energy for welding than the upper section. Accordingly, it may be preferable for the opposing section (310) to be positioned to correspond to the upper section rather than the middle section of the multiple electrode tabs (120). Accordingly, the middle section of the multiple electrode tabs (120) can be welded by passing through the first electrode lead (200) that does not overlap with the opposing section (310). Of course, since the lower end of the multiple electrode tabs (120) is not involved with the electrode tab (120) extending from the upper section, the degree of overlap may be reduced again. However, as shown in FIG. 2, the lower end is exposed to the outside of the first electrode lead (200), so it may not be a matter of consideration that the laser must penetrate the electrode lead (EL).

[0087] A lead film (400) may be positioned in the middle of the extension portion (320). The lead film (400) may have a plastic material and may have properties similar to the inner surface of the battery case (10). As shown in FIG. 8, the lead film (400) may be positioned between the lead sealing portions (12a). During the fusion of the lead sealing portions (12a), the lead film (400) may be fused to the lead sealing portions (12a) because it has properties similar to the lead sealing portions (12a). This may provide a higher sealing force than when the electrode lead (EL) is simply positioned directly between the lead sealing portions (12a). Since the electrode lead (EL) may have a metal material, and considering the properties that make it difficult for the electrode lead (EL) and the inner surface of the lead sealing portions (12a) to adhere to each other, the lead film (400) may be necessary for sealing.

[0088] A coupling slit (311H) that overlaps with the electrode tab (120) may be formed in the electrode lead (EL). Here, the concept of overlap may include not only the coupling slit (311H) being in a position where it completely touches the electrode tab (120), but also overlapping with the area to which the electrode tab (120) belongs when the area is extended. As shown in FIG. 2, since the coupling slit (311H) is located in an area positioned in front of the electrode tab (120), in this case as well, the coupling slit (311H) can be said to overlap with the electrode tab (120).

[0089] A coupling slit (311H) may be formed on the opposing portion (310) of the second electrode lead (300). Although FIG. 2 appears to show a coupling slit (311H) formed at a location other than the opposing portion (310), the coupling slit (311H) may be formed only on the opposing portion (310) as needed. As shown in FIG. 4, a laser may be radiated toward the coupling slit (311H) after the electrode lead (EL) and the electrode tab (120) come into contact. In this case, if there is no coupling slit (311H), the laser must pass over the opposing portion (310) of the second electrode lead (300) and the first electrode lead (200) to reach the electrode tab (120). However, as in the first embodiment of the present invention, when a coupling slit (311H) is formed in the opposing portion (310), the laser reaches the electrode tab (120) by passing through the coupling slit (311H) and penetrating only the first electrode lead (200) without needing to pass through the opposing portion (310), thus making it easier to transmit energy to the electrode tab (120). Furthermore, as the electrode tab (120) is bent, the degree of overlap between the electrode tabs (120) in the front-rear direction increases, which may cause a problem where the laser welding does not transmit enough energy to weld the electrode tabs (120) together. Considering this point, the laser transmitted through the coupling slit (311H) can supply stronger energy to the electrode tab (120), which may help solve this problem.

[0090] At this time, the coupling slit (311H) may be extended in the overall vertical direction. Of course, depending on the shape of the electrode lead (EL), a portion of the coupling slit (311H) that extends in the front-rear direction may be provided. In other words, the coupling slit (311H) may be extended in the direction in which the electrode tab (120) is bent. To weld the electrode tab (120), a laser may be moved vertically along the extension direction of the coupling slit (311H) as shown in FIG. 4. At this time, the laser continues to move in the direction of movement so that a welding line (WL) can be formed vertically as shown in FIG. 5. Compared to the case where the extension direction of the coupling slit (311H) is horizontal, when the welding line (WL) is formed horizontally, a portion may be formed where some parts are welded and some parts are not welded with respect to the stacking direction of the electrode tab (120). However, since the vertical welding line (WL) passes through the entire stacking direction of the electrode tab (120), welding can be performed on the entire stacking direction of the electrode tab (120). From the perspective of whether the electrode tab (120) is welded thoroughly, the vertical welding line (WL) may be better than the horizontal welding line (WL).

[0091] At this time, the coupling slit (311H) may include a slit (311Hb) formed on the opposing part (310) as shown in FIG. 2 and a lead slit (311Ha) formed on the first electrode lead (200) as shown in FIG. 3.

[0092] The opposing slit (311Hb) may be formed extending to a part of the extension (320). The opposing slit (311Hb) formed in the extension (320) may function as a structure for discharging heat applied to the electrode lead (EL) when a laser is emitted through the opposing slit (311Hb). This is because the surface area of ​​the extension (320) increases when the opposing slit (311Hb) extends to the extension (320). At this time, the opposing slit (311Hb) may be extended to the position where the lead film (400) is formed with respect to the extension (320). This is because if the opposing slit (311Hb) extends to the lead film (400), the lead sealing portion (12a) may be hindered from fusing with the lead film (400).

[0093] The lead slit (311Ha) can be connected to the opposing slit (311Hb). Accordingly, when manufacturing the electrode lead (EL), the lead slit (311Ha) and the opposing slit (311Hb) can be formed at once, thereby improving processability.

[0094] The lead slit (311Ha) may partially overlap with the opposing slit (311Hb). More specifically, the first electrode lead (200) may only partially overlap with the electrode tab (120), and the lead slit (311Ha) may not overlap with the electrode tab (120). During the welding process, it is necessary for multiple electrode tabs (120) to be welded together, but it is also necessary to be welded with the electrode lead (EL). Accordingly, if a coupling slit (311H) is located at the part of the electrode lead (EL) that is welded to the electrode tab (120), the electrode tab (120) melts, but there is no electrode lead (EL) to be coupled with the melted electrode tab (120), so it may be difficult to combine the electrode lead (EL) and the electrode tab (120). Accordingly, it may be preferable that a coupling slit (311H) is not formed in the portion of the first electrode lead (200) that overlaps with the electrode tab (120). Accordingly, it may also be preferable that a lead slit (311Ha) is not formed in the portion that overlaps with the electrode tab (120). However, if necessary, a lead slit (311Ha) may be formed for a different purpose in the portion that overlaps with the electrode tab (120).

[0095] Considering the above, the lead slit (311Ha) may not extend to a portion that does not overlap with the opposing portion (310) of the first electrode lead (200). In other words, as shown in FIG. 3, the lower side of the first electrode lead (200) may be smooth without the formation of the lead slit (311Ha).

[0096] The electrode lead (EL) according to the first embodiment of the present invention described above can be moved to come into contact with the bent electrode tab (120) as shown in FIG. 2. As shown in FIG. 4, a laser can be emitted through the coupling slit (311H) to join the electrode tab (120) and the electrode lead (EL) together. At this time, the method of joining the electrode tab (120) and the electrode lead (EL) is not limited to laser welding, and if necessary, other methods other than welding, such as a clinch method, may be used. According to laser welding, a welding line (WL) is formed vertically as shown in FIG. 5 and can be provided in multiple numbers and arranged left and right. At this time, as shown in FIG. 5, the electrode tab (120) can be exposed and extended on the lower side of the electrode body (110). Since a dead space (DS) can be formed by this part, the lower end of the electrode tab (120) can be folded upward as shown in FIG. 6. At this time, the end of the folded electrode tab (120) can be defined as the folding end (121). That is, the folding end (121) can be folded at one end of the first electrode lead (200) and bent toward the opposite side. As shown in FIG. 7, the folding end (121) can be welded in the horizontal direction. Compared to welding in the vertical direction, welding in the horizontal direction may have the advantage of a simpler laser path for welding. In particular, considering that the width direction of the first electrode lead (200) is longer than the height direction, welding in the horizontal direction can be performed with fewer steps than welding in the vertical direction. Since the multiple electrode tabs (120) have already been joined together by previous welding, welding to join the folding end (121) to the first electrode lead (200) can be performed using a high-speed transverse welding method.Furthermore, since the horizontal welding here is a welding in a different direction from the preceding vertical welding, if the vertical welding receives a force for disengagement from a specific direction, the horizontal welding will be vulnerable to disengagement in a direction different from the direction in which the vertical welding is vulnerable to disengagement, and thus the connection may not be disengaged. Therefore, two weldings in different directions may be desirable for maintaining the connection. Considering this point, the welding direction of the folding end (121) may be different from the extension direction of the connection slit (311H) as needed.

[0097] Accordingly, a secondary battery (B) as shown in FIG. 10 can be provided.

[0098] 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.

[0099] 2nd embodiment

[0100] FIG. 9 is a perspective view of an electrode lead (EL-1) according to a second embodiment of the present invention.

[0101] As illustrated in FIG. 9, an electrode lead (EL-1) according to a second embodiment of the present invention is described.

[0102] The second embodiment differs from the first embodiment in that the direction of the connecting slit (311H-1) is different.

[0103] The joining slit (311H-1) can be extended in the horizontal direction. Accordingly, the number of welding steps for joining the electrode tab (120) can be reduced compared to the case of the first embodiment.

[0104] Third embodiment

[0105] FIG. 10 is a perspective view of an electrode lead (EL-2) according to a third embodiment of the present invention.

[0106] Referring to FIG. 10, an electrode lead (EL-2) according to a third embodiment of the present invention will be described.

[0107] The third embodiment differs from the first embodiment in that the lead slit (311Ha-2) of the coupling slit (311H-2) extends to the lower side of the first electrode lead (200).

[0108] At this time, the lead slit (311Ha-2) may have a width small enough so that the first electrode lead (200) and the electrode tab (120) can be welded even if laser welding penetrates the lead slit (311Ha-2) and is transmitted to the first electrode tab (120a).

[0109] 4th embodiment

[0110] FIG. 11 is an assembly diagram of an electrode assembly (EA-3) according to a fourth embodiment of the present invention.

[0111] Referring to FIG. 11, an electrode assembly (EA-3) according to the fourth embodiment of the present invention will be described.

[0112] The fourth embodiment differs from the first embodiment in that electrode tabs (120) having different bending directions are formed on the same side of the electrode body (110).

[0113] The electrode tab (120) may include a first electrode tab (120a-3) and a second electrode tab (120b-3) that are located on the same side in the direction of the electrode (100) and are bent in different directions. The first electrode tab (120a-3) and the second electrode tab (120b-3) may have the same polarity.

[0114] In the upper region of the plurality of first electrode tabs (120a-3), the plurality of first electrode tabs (120a-3) may overlap less, and in the upper region of the plurality of second electrode tabs (120b-3), the plurality of second electrode tabs (120b-3) may overlap more. At this time, the same energy can be radiated by the electrode lead (EL) to the upper region of the plurality of first electrode tabs (120a-3) and the upper region of the plurality of second electrode tabs (120b-3), thereby allowing one to be coupled with the other, while the other may not be sufficiently coupled with the other. Accordingly, since one is coupled, it can be arranged so that there are no points between electrode tabs of the same height that are not coupled with each other.

[0115] 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.

[0116] 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.

[0117] [Explanation of the symbol]

[0118] B: Secondary battery

[0119] 10: Battery case

[0120] 11: Reception Department

[0121] 11S: Electrode receiving space

[0122] 12: Side

[0123] 12a: Lead sealing part

[0124] 12b: Degas sealing part

[0125] 12c: Folding part

[0126] EA: Electrode assembly

[0127] 100: Electrode

[0128] 110: Electrode body

[0129] 120: Electrode tab

[0130] 121: Folding end

[0131] 120a-3: First electrode tab

[0132] 120b-3: Second electrode tab

[0133] EL: Electrode lead

[0134] 200: First electrode lead

[0135] 300: Second electrode lead

[0136] 310: Opposite part

[0137] 311H: Connecting slit

[0138] 311Ha: Lead slit

[0139] 311Hb: Opposing slit

[0140] 320: Extension part

[0141] 400: Lead film

[0142] DS: Dead Space

[0143] H: Lead height

[0144] WL: Welding line

Claims

1. Electrodes including electrode tabs, provided in plurality and stacked in one direction; and It includes an electrode lead coupled to the electrode tab above, and The above electrode tab is bent in a direction in which a plurality of the electrodes are stacked, and The above electrode lead is an electrode assembly in which a coupling slit is formed that overlaps with the electrode tab.

2. In Paragraph 1, The above-mentioned coupling slit is an electrode assembly that extends in the direction in which the electrode tab is bent.

3. In Paragraph 1, The above electrode lead includes a first electrode lead directly coupled to the electrode tab and 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.

4. In Paragraph 3, The above extension is formed by being bent at the above opposing portion, and The first electrode lead is an electrode assembly that overlaps only partially with the opposing part.

5. In Paragraph 3, The first electrode lead and the second electrode lead are integrally formed, and The above-mentioned opposing portion is an electrode assembly formed by bending the first electrode lead.

6. In Paragraph 3, The above-mentioned coupling slit is an electrode assembly comprising an opposing slit formed in the opposing portion.

7. In Paragraph 6, The above-mentioned opposing slit is an electrode assembly formed by extending to a part of the above-mentioned extension.

8. In Paragraph 7, It further includes a lead film coupled to the above extension, The above-mentioned opposing slit is an electrode assembly that extends to the position where the lead film is formed with respect to the above-mentioned extension.

9. In Paragraph 3, The above coupling slit is an electrode assembly comprising a lead slit formed in the first electrode lead.

10. In Paragraph 9, The above-mentioned coupling slit further includes an opposing slit formed in the opposing portion, and The above lead slit is an electrode assembly connected to the above opposing slit.

11. In Paragraph 9, The above-mentioned coupling slit includes an opposing slit formed in the opposing portion, and The above lead slit is an electrode assembly that overlaps at least partially with the above opposing slit.

12. In Paragraph 9, The first electrode lead overlaps only a portion of the electrode tab, and The above lead slit is an electrode assembly that does not overlap with the above electrode tab.

13. In Paragraph 9, The above extension is formed by being bent at the above opposing portion, and The first electrode lead overlaps only partially with the opposing part, and The above lead slit is an electrode assembly that does not extend to a portion that does not overlap with the opposing portion of the first electrode lead.

14. In Paragraph 3, The electrode tab is an electrode assembly having a folding end that is folded at one end of the first electrode lead and bent toward the opposite side.

15. In Paragraph 14, The above folding end is welded and joined to the first electrode lead, and An electrode assembly in which the welding direction of the above-mentioned folding end is different from the extension direction of the above-mentioned joining slit.

16. Electrode assembly; and It includes a battery case that accommodates the above electrode assembly, The above electrode assembly is, Electrodes including electrode tabs, provided in plurality and stacked in one direction; and It includes an electrode lead coupled to the electrode tab above, and The above electrode tab is bent in a direction in which a plurality of the electrodes are stacked, and The above electrode lead is a secondary battery in which a coupling slit is formed that overlaps with the electrode tab.

17. In Paragraph 16, The above-mentioned coupling slit is a secondary battery that extends in the direction in which the electrode tab is bent.

18. In Paragraph 16, The above electrode lead includes a first electrode lead directly coupled to the electrode tab and 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.

19. In Paragraph 18, The above-mentioned coupling slit is a secondary battery comprising an opposing slit formed in the opposing portion.

20. A first electrode lead configured to be directly coupled to an electrode tab; 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 It includes an extension portion extending in a direction away from the electrode at the above-mentioned opposing portion, and The above-mentioned opposing portion is an electrode lead in which a coupling slit is formed that overlaps with the electrode tab.

Images