Secondary battery

Abstract

The present invention relates to a secondary battery comprising: an electrode assembly comprising an electrode tab; a case including an accommodating portion accommodating the electrode assembly; and an electrode lead connected with the electrode tab of the electrode assembly and disposed inside the case, in which the case further includes an exposure hole opened to expose a portion of the electrode lead to the outside of the case, the electrode lead including: an exposure portion exposed to the outside of the case through the exposure hole; and a non-exposed portion connected with the exposed portion and covered by the housing so as not to be exposed to the outside of the housing, and the exposed portion may include a protruding portion protruding further to the outside of the housing than the non-exposed portion.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0146377 filed on November 4, 2022, Korean Patent Application No. 10-2022-0146378 filed on November 4, 2022, Korean Patent Application No. 10-2022-0146379 filed on November 4, 2022, and Korean Patent Application No. 10-2023-0150797 filed on November 3, 2023, which are hereby incorporated by reference in their entirety. Technical Field

[0004] The present disclosure relates to a secondary battery. Background Art

[0005] Generally, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used in electronic devices such as mobile phones, notebook computers and camcorders, electric vehicles, etc. In particular, a lithium secondary battery has a larger capacity and higher energy density than a nickel-cadmium battery or a nickel-metal hydride battery, and thus its utilization rate tends to increase rapidly.

[0006] According to the shape of the battery case, secondary batteries can be classified into cylindrical batteries and square batteries each having an electrode assembly embedded in a cylindrical or square metal can and a pouch type battery having an electrode assembly embedded in a pouch type case made of an aluminum laminate sheet or the like.

[0007] Figure 1 is a diagram showing an example of a soft-pack type secondary battery. The soft-pack type secondary battery 1 includes an electrode assembly 2 in which electrodes and separators are alternately stacked, and a soft-pack type outer shell 20 accommodating the electrode assembly 2. Electrode tabs 15 may be connected to electrodes of the electrode assembly 2, respectively. The electrode tabs 15 may be welded to each other in a predetermined area and then connected to the electrode lead 17 by welding. The outer shell 20 includes an accommodating portion 21 for accommodating the electrode assembly 2. The accommodating portion 21 of the outer shell 20 may be provided in one portion or two portions each having a concave shape. Figure 1 An example is shown in which the accommodation portion 21 is provided in two portions each having a concave shape. A sealing portion 23 (land) is formed around the accommodation portion 21 by sealing.

[0008] The secondary battery needs to prevent fire or explosion from occurring in the secondary battery even when the internal temperature or pressure rises rapidly. When this cannot be prevented, problems with thermal runaway or heat propagation may occur. However, in the soft-pack type secondary battery according to the related art, the sealing portion 23 is generally formed by heat sealing, and therefore, the sealing strength of the sealing portion 23 is not high enough to prevent or delay fire or explosion. In addition, when the electrode lead 17 passes through the sealing portion 23 to be exposed to the outside of the housing 20, a portion of the sealing portion 23 through which the electrode lead 17 passes may have a lower sealing strength than other portions.

[0009] In particular, recently, a soft-pack type battery in which exhaust occurs only at a specific point even at a very high temperature (e.g., 1000° C.) is required. In a soft-pack type secondary battery according to the related art, the sealing portion 23 is generally formed by heat-sealing between resin layers (which may be layers made of polypropylene) of the outer case 20. Therefore, since the resin layer of the sealing portion 23 may melt at a very high temperature, resulting in exhaust at an unexpected point, it is difficult to meet the requirements as described above. Summary of the invention

[0010] Technical issues

[0011] An object of the present invention is to provide a secondary battery which sufficiently ensures the sealing strength of a sealing portion so as to prevent or delay the occurrence of fire or explosion in the secondary battery even when the internal temperature or pressure rises rapidly at a very high temperature.

[0012] In addition, another object of the present invention is to provide a secondary battery in which a portion through which an electrode lead passes is not provided in the sealing portion of the outer shell, so that a portion with relatively low sealing strength is not formed in the sealing portion, so that accidental exhaust does not occur even at very high temperatures.

[0013] In addition, another object of the present invention is to provide a secondary battery, which is provided with a sealing area having a lower sealing strength than a sealing part inside the outer shell, so that even when the internal pressure rises rapidly at a very high temperature, the sealing area inside the outer shell (i.e., an unexpected point) ruptures first before the sealing part ruptures to reduce the internal pressure.

[0014] Furthermore, another object of the present invention is to provide a secondary battery capable of easily electrically connecting an electrode lead provided inside a case to another portion.

[0015] Furthermore, another object of the present invention is to provide a secondary battery in which an outer case is not damaged due to an electrode lead disposed inside the outer case during molding of a sealing portion.

[0016] Technical Solution

[0017] In an embodiment, a secondary battery may include: an electrode assembly, the electrode assembly including an electrode terminal tab; a shell, the shell including a accommodating portion for accommodating the electrode assembly; and an electrode lead, the electrode lead being connected to the electrode terminal tab of the electrode assembly and being disposed inside the shell, wherein the shell also includes an exposure hole opened to expose a portion of the electrode lead to the outside of the shell, wherein the electrode lead includes: an exposed portion, the exposed portion being exposed to the outside of the shell through the exposure hole; and a non-exposed portion, the non-exposed portion being connected to the exposed portion and covered by the shell so as not to be exposed to the outside of the shell, wherein the exposed portion includes a protrusion that protrudes toward the outside of the shell more than the non-exposed portion.

[0018] In another embodiment, the protrusion may protrude at least to the outer surface of the housing more than the non-exposed portion.

[0019] In another embodiment, the protrusion may be spaced apart from the edge of the exposure hole by a predetermined distance.

[0020] In another embodiment, the secondary battery may further include an insulating member disposed in an empty space provided by the spacing for electrical insulation between the protrusion and the case.

[0021] In another embodiment, the housing may include: a housing sealing portion which at least partially surrounds the accommodating portion; and an exposure hole sealing portion which surrounds the exposure hole, wherein the housing sealing portion seals more tightly than the exposure hole sealing portion.

[0022] In another embodiment, the housing sealing portion may be formed by welding, and the exposure hole sealing portion may be formed by fusion.

[0023] In another embodiment, the shell may also include: a first shell, the first shell including a first metal layer; a second shell, the second shell is arranged to face the first shell to form a accommodating portion together with the first shell, and includes a second metal layer; a shell sealing portion, the shell sealing portion sealingly combines the first shell and the second shell to each other and at least partially surrounds the accommodating portion; and an exposure hole sealing portion, the exposure hole sealing portion is arranged on an exposure hole shell of the first shell and the second shell as a shell in which the exposure hole is defined, and surrounds the exposure hole.

[0024] In another embodiment, the housing seal may be formed by welding between the first metal layer and the second metal layer.

[0025] In another embodiment, the first shell may also include a first resin layer arranged inside the first metal layer, the second shell may also include a second resin layer arranged inside the second metal layer to face the first resin layer, and the shell sealing part can be formed by welding the first metal layer and the second metal layer in a state where the first metal layer and the second metal layer are in direct contact with each other without the first resin layer and the second resin layer.

[0026] In another embodiment, each of the first metal layer and the second metal layer may include stainless steel.

[0027] In another embodiment, the secondary battery may further include an insulating film disposed between the exposure hole housing and the electrode lead to surround a portion of the electrode lead exposed through the exposure hole, wherein the exposure hole sealing portion is formed by welding between the insulating film and a resin layer of the exposure hole housing disposed to face the insulating film.

[0028] In another embodiment, the housing seal may be provided to entirely surround the accommodation portion except for a portion where the first housing and the second housing are connected to each other, and the electrode lead may be provided inside the housing without passing through the housing seal.

[0029] In another embodiment, the electrode lead may extend in a direction intersecting with an extending direction of the electrode tab and be disposed inside the housing.

[0030] In another embodiment, the accommodating portion may include: an electrode assembly accommodating portion accommodating the electrode assembly; and an electrode lead accommodating portion accommodating at least a portion of the electrode lead.

[0031] In another embodiment, before accommodating the electrode assembly, the electrode assembly accommodating portion may be pre-molded into a shape for accommodating the electrode assembly, and before accommodating the electrode lead, the electrode lead accommodating portion may be pre-molded into a shape for accommodating the electrode lead.

[0032] In another embodiment, the electrode lead may be disposed to be electrically connected to an electrode lead of another secondary battery through a protrusion.

[0033] In another embodiment, the secondary battery may further include an insulating film disposed between the exposure hole housing and the electrode lead to surround a portion of the electrode lead exposed through the exposure hole, wherein a surface treatment portion for increasing the surface roughness is locally disposed on the surface of the electrode lead, wherein the area where the surface treatment portion is disposed includes an area of ​​the surface of the electrode lead facing the insulating film.

[0034] In another embodiment, a secondary battery may include: an electrode assembly, the electrode assembly including an electrode tab; a shell, the shell including a housing for accommodating the electrode assembly; and an electrode lead, the electrode lead being connected to the electrode tab of the electrode assembly and disposed inside the shell, wherein the shell also includes an exposure hole opened to expose at least a portion of the electrode lead to the outside of the shell.

[0035] In another embodiment, the electrode lead may be disposed to be electrically connected to an electrode lead of another secondary battery through the exposure hole.

[0036] In another embodiment, the electrode lead may extend in a direction intersecting with an extending direction of the electrode tab and be disposed inside the housing such that the electrode tab is disposed at a middle portion of the electrode lead with reference to the intersecting direction.

[0037] In another embodiment, the electrode tab may be bent toward a side surface of the electrode assembly from which the electrode tab protrudes, so that a side surface of the electrode lead faces a side surface of the electrode assembly.

[0038] In another embodiment, the electrode tab may be bent toward the outermost surface of the electrode assembly so that one side of the electrode lead faces the outermost surface of the electrode assembly based on the direction in which the electrodes and the separator of the electrode assembly are stacked.

[0039] In another embodiment, a secondary battery may include: an electrode assembly, the electrode assembly including an electrode tab; an outer shell, the outer shell including a accommodating portion for accommodating the electrode assembly; and an electrode lead, the electrode lead being connected to the electrode tab of the electrode assembly and disposed inside the outer shell, wherein the accommodating portion includes: an electrode assembly accommodating portion, the electrode assembly accommodating portion accommodating the electrode assembly; and an electrode lead accommodating portion, the electrode lead accommodating portion accommodating at least a portion of the electrode lead.

[0040] In another embodiment, the housing may further include a housing sealing portion at least partially surrounding the accommodation portion, wherein the electrode lead accommodation portion is disposed on the housing sealing portion and inside the housing to accommodate the electrode lead.

[0041] In another embodiment, one side of the electrode lead accommodating portion facing the electrode assembly accommodating portion may be in communication with the electrode assembly accommodating portion, and the remaining side of the electrode lead accommodating portion may be surrounded by the housing sealing portion.

[0042] In another embodiment, the housing may further include an exposure hole opened to expose at least a portion of the electrode lead to the outside of the housing.

[0043] In another embodiment, the electrode tab may be bent toward a side of the electrode assembly from which the electrode tab protrudes, so that one side of the electrode lead faces a side of the electrode assembly, and the exposure hole may be defined on a side of the outer shell facing another side of the electrode lead through the bending of the electrode tab.

[0044] In another embodiment, the electrode tab may be bent toward the outermost surface of the electrode assembly so that one side of the electrode lead faces the outermost surface of the electrode assembly with respect to the direction of the electrodes and the diaphragm of the stacked electrode assembly, and the exposure hole may be defined on a side of the outer shell that faces the other side of the electrode lead through the bending of the electrode tab.

[0045] Beneficial Effects

[0046] According to the present invention, the electrode lead can be arranged inside the shell, and the electrode lead can be exposed through the exposure hole of the shell, so that the edge of the shell is sealed as a whole without providing a portion of the edge of the shell through which the electrode lead passes. Therefore, the overall sealing of the shell can be performed more tightly.

[0047] According to the present invention, the housing seal can be arranged to have a relatively high sealing strength. Therefore, even when the temperature or internal pressure of the secondary battery rises rapidly, a fire or explosion in the secondary battery can be prevented or delayed. In addition, the exposure hole seal can be sealed to have a relatively low sealing strength, so that when the internal pressure of the secondary battery rises rapidly, the exposure hole seal is first caused to rupture (generating exhaust at a predetermined point), thereby reducing the internal pressure before the housing seal ruptures.

[0048] According to the present invention, the housing seal can be formed by welding between metal layers having a very high melting point, so that the sealing strength of the housing seal is very high. Therefore, the seal will not break even at a very high temperature.

[0049] According to the present invention, the electrode lead may include a protrusion protruding toward the outside of the housing, and thus the electrode lead may be easily electrically connected to other portions.

[0050] According to the present invention, the electrode lead receiving portion can receive the electrode lead, and thus damage caused by the electrode lead does not occur in the case during the process of sealing the edge of the case to form the case sealing portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a diagram showing an example of a pouch-type secondary battery.

[0052] Figure 2 is a perspective view showing a secondary battery according to Embodiment 1 of the present invention.

[0053] Figure 3 yes Figure 2 An exploded perspective view of a secondary battery in FIG.

[0054] Figure 4 and Figure 5 It is shown Figure 2 A cross-sectional view of the layer structure of the outer casing of a secondary battery.

[0055] Figure 6 is a perspective view showing a secondary battery according to Embodiment 2 of the present invention.

[0056] Figure 7 yes Figure 6 An exploded perspective view of a secondary battery in FIG.

[0057] Figure 8 It is shown Figure 7 Exploded perspective view of Modification 1 of the secondary battery in FIG.

[0058] Fig. 9 It is shown Figure 7 Exploded perspective view of Modification 2 of the secondary battery in FIG.

[0059] Fig.10 It is shown Figure 7 Exploded perspective view of Modification 3 of the secondary battery in FIG.

[0060] Fig.11 It is shown Figure 7 Exploded perspective view of Modification 4 of the secondary battery in FIG.

[0061] Fig.12 is a perspective view showing a secondary battery according to Embodiment 3 of the present invention.

[0062] Fig.13 yes Fig.12 An exploded perspective view of a secondary battery in FIG.

[0063] Fig.14 It is along Fig.12 A cross-sectional view taken along line AA'.

[0064] Fig.15 is a cross-sectional view showing another example of providing an insulating member.

[0065] Fig.16 and Fig.17 is a perspective view illustrating electrical connection of a secondary battery according to Embodiment 1. DETAILED DESCRIPTION

[0066] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments described herein.

[0067] In order to clearly describe the present invention, parts that are irrelevant to the description or detailed description of related well-known technologies that may unnecessarily obscure the subject matter of the present invention will be excluded. Throughout the specification, the same reference numerals denote the same elements.

[0068] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms to best describe and interpret his or her invention.

[0069] Example 1

[0070] Figure 2 is a perspective view showing a secondary battery according to Embodiment 1 of the present invention. Figure 3 yes Figure 2 An exploded perspective view of a secondary battery in FIG. Figure 2 and Figure 3 As shown, the secondary battery 100 according to this embodiment may include an electrode assembly 110, a housing 130, and an electrode lead 150. Figure 3 The secondary battery 100 according to this embodiment is described in detail. For reference, the same details of the secondary battery according to Embodiment 1 may be applied to secondary batteries according to Embodiments 2 and 3 to be described later as long as there is no conflict therebetween.

[0071] Overall structure of secondary battery

[0072] like Figure 3 As shown, an electrode assembly 110 may be provided by alternately stacking electrodes and separators. The electrodes may include a positive electrode and a negative electrode. The electrode assembly 110 may include an electrode tab 111. A separately provided electrode tab may be connected to the electrode, and a portion of a current collector constituting the electrode may be used as the electrode tab.

[0073] The case 130 may include a receiving portion 131 for receiving the electrode assembly 110. The case 130 may be a soft pack type case.

[0074] The outer case 130 may be disposed such that the first outer case 141 and the second outer case 142 disposed to face each other are combined to be sealed with each other in a state where the electrode assembly 110 is accommodated. Figure 3As shown, the first housing 141 and the second housing 142 can be combined with each other in a state of being separately set. Here, the edge of the first housing 141 and the edge of the second housing 142 can be completely sealed. The housing sealing portion 132 (see FIG. 140 ) to be described later can be formed by such sealing. Figure 2 ). Alternatively, the first housing and the second housing may be combined with each other by being provided as a part and the remaining part of one housing, which are provided to face each other when one housing is folded (see Figure 1 ). Here, the remaining edges except for the portion where the first shell and the second shell are connected to each other (i.e., the portion where one shell is folded) may be sealed. For reference, as will be described later, at least a portion of the electrode lead 150 may be disposed on the shell sealing portion 132, and when the edge of the first shell 141 and the edge of the second shell 142 are sealed to each other via the electrode lead 150, a portion protruding outward as a protrusion due to the electrode lead 150, etc. may be disposed on the first shell 141 and the second shell 142, such as Figure 2 shown.

[0075] Before the first case 141 is combined with the second case 142, the receiving portion 131 of the case 130 may be pre-molded into a shape for receiving the electrode assembly 110. For example, the receiving portion 131 may include an electrode assembly receiving portion 131a pre-molded before receiving the electrode assembly 110. When the first case 141 and the second case 142 have a film shape, the receiving portion 131 may be provided by pressing one or both of the first case 141 and the second case 142 using a punch to provide an internal space and combining the cases 141 and 142 to face each other. Figure 3 An example in which an internal space is defined in each of the first housing 141 and the second housing 142 is shown. For reference, Figure 2 and Figure 3 An example of a battery in which the accommodation portion 131 is provided in each of the first housing 141 and the second housing 142 is shown. However, the details of this embodiment can also be applied to a battery in which the accommodation portion is provided in one of the first housing and the second housing. The same applies to other embodiments to be described later.

[0076] The electrode lead 150 may be connected to the electrode tab 111 of the electrode assembly 110. The electrode lead 150 may be connected to the electrode tab 111 by being welded to the electrode tab 111 that has been welded to each other in a predetermined region.

[0077] The electrode lead 150 may be disposed inside the housing 130. In a secondary battery according to the related art, the electrode lead includes a portion disposed inside the housing and a portion extending to the outside of the housing for electrical connection with another secondary battery. However, the electrode lead 150 according to this embodiment may not include a portion extending to the outside of the housing 130.

[0078] For example, Figure 2 and Figure 3 As shown, the electrode lead 150 according to this embodiment can be disposed inside the housing 130 without extending from the edge of the housing 130. When there is a portion where the first housing 141 and the second housing 142 are connected to each other, in addition to the connection portion (in Figure 2 and Figure 3 The housing seal portion 132 may be configured to entirely surround the accommodation portion 131 (see Figure 2 ), and the electrode lead 150 (which may partially overlap but) may be disposed inside the housing 130 without passing through the housing sealing portion 132.

[0079] For reference, the wording "except for the portion where the first outer shell and the second outer shell are connected to each other" means that the secondary battery according to this embodiment "includes the portion where the first outer shell and the second outer shell are connected to each other". If there is no portion where the first outer shell and the second outer shell are connected to each other, there is no portion to be "excluded", so the outer shell sealing portion can be set to surround the entire accommodating portion.

[0080] like Figure 2 As shown, the housing 130 according to this embodiment may include an exposure hole 133 opened to expose at least a portion of the electrode lead 150 to the outside of the housing 130. A portion of the housing 130 may be cut at a portion corresponding to the electrode lead 150 to define the exposure hole 133. For example, during a process of forming the accommodation portion 131 in the housing 130 having a film shape, or before or after the process, the housing 130 may be penetrated to define the exposure hole 133. Figure 3 An example is shown in which the exposure hole 133 is defined in each of the first and second outer shells 141 and 142. Even when the electrode lead 150 does not include a portion extending to the outside of the outer shell 130, the electrode lead 150 may be exposed to the outside of the outer shell 130 through the exposure hole 133.

[0081] In the secondary battery 100 according to this embodiment, since the electrode lead 150 is disposed inside the outer shell 130 and the electrode lead 150 is exposed through the exposure hole 133 of the outer shell 130, the edge of the outer shell 130 can be sealed as a whole without providing a portion of the edge of the outer shell 130 through which the electrode lead 150 passes. The portion of the edge of the outer shell through which the electrode lead passes is a portion where the first outer shell and the second outer shell can be sealed weaker than other portions. Since the secondary battery 100 according to this embodiment does not include this portion, the first outer shell 141 and the second outer shell 142 can be sealed more tightly as a whole. Even when the temperature or internal pressure of the secondary battery 100 rises rapidly, a fire or explosion in the secondary battery 100 can be prevented or delayed. Therefore, thermal runaway or heat propagation can be prevented or delayed.

[0082] Housing seal and exposure hole seal

[0083] like Figure 2 As shown, the housing 130 may include a housing seal portion 132 disposed to at least partially surround the receiving portion 131. The housing seal portion 132 may be formed by sealing an edge of the first housing 141 and an edge of the second housing 142 together.

[0084] like Figure 2 and Figure 3 As shown in , when the first shell 141 and the second shell 142 are provided respectively, the shell sealing portion 132 can be completely arranged on the edge of the first shell 141 and the edge of the second shell 142. Here, the shell sealing portion 132 can be arranged to surround the accommodating portion 131 as a whole. When the first shell and the second shell are provided by folding one shell, the shell sealing portion can be arranged on the edges of the first shell and the second shell except the folded portion. The shell sealing portion can also be arranged on the boundary between the folded portion and the non-folded portion (that is, the two ends of the folded portion). Here, the shell sealing portion can be arranged to surround only a portion of the accommodating portion. The shell sealing portion 132 according to this embodiment can be formed by welding as described later.

[0085] like Figure 2 As shown, the housing 130 may include a housing 130 configured to surround the exposure hole 133 (see Fig.17The exposure hole sealing portion 134 is shown in FIG. 1 (a dotted line of the enlarged portion in FIG. 1 ). Since the exposure hole 133 is a portion where the sealing of the housing 130 is broken by the housing sealing portion 132, sealing of the exposure hole 133 may be necessary, and the exposure hole sealing portion 134 may perform sealing. The exposure hole 133 may be defined in one or each of the first housing 141 and the second housing 142, and the exposure hole sealing portion 134 may be provided on the housings of the first housing 141 and the second housing 142 in which the exposure hole 133 is defined (hereinafter, referred to as "exposure hole housings"). As described later, the exposure hole sealing portion 134 according to this embodiment may be formed by welding (e.g., heat sealing).

[0086] In the secondary battery 100 according to this embodiment, the housing seal 132 may be more tightly sealed than the exposure hole seal 134. In the secondary battery 100 according to this embodiment, the housing seal 132 may be sealed to have a relatively high sealing strength, so that even when the temperature or internal pressure of the secondary battery 100 rises rapidly, a fire or explosion in the secondary battery 100 may be prevented or delayed. In addition, the exposure hole seal 134 may be sealed to have a relatively low sealing strength, so that when the internal pressure of the secondary battery 100 rises rapidly, the exposure hole seal 134 is first caused to rupture (i.e., exhaust is generated at a predetermined point) to reduce the internal pressure before the housing seal 132 is ruptured.

[0087] Detailed structure of the housing seal

[0088] As described above, the housing 130 may include the first housing 141 and the second housing 142 disposed to face the first housing 141 to provide the accommodation portion 131 together with the first housing 141. Figure 4 As shown, the first housing 141 and the second housing 142 may include a first metal layer 141a and a second metal layer 142a, respectively. Figure 5 As shown, the housing seal 132 that seals the first housing 141 and the second housing 142 can be formed by welding between these metal layers 141a and 142a. The welding can be laser welding. The first metal layer 141a can include aluminum. Alternatively, the first metal layer 141a can include stainless steel. For example, the first metal layer 141a can be a layer made of stainless steel. The second metal layer 142a can also include aluminum or stainless steel.

[0089] Recently, there is a need for a soft-pack type battery in which venting occurs only at a specific point even at a very high temperature (e.g., 1000° C.). In a soft-pack type secondary battery according to the related art, a housing seal is generally formed by heat-sealing between resin layers (which may be layers made of polypropylene) of the housing, and the resin layer may melt at a very high temperature to cause venting to occur at an unexpected point.

[0090] However, similar to the secondary battery 100 according to this embodiment, when the outer shell seal is formed by welding between metal layers (specifically, layers made of stainless steel) having a very high melting point, the sealing strength of the outer shell seal is very high, so the seal will not break even at very high temperatures. In addition, when the outer shell seal is formed by welding on the entire edge of the outer shell except for the portion where the first outer shell and the second outer shell are combined with each other, the effect as described above can be further enhanced. When the internal pressure of the secondary battery is very high, exhaust can be caused by the exposed hole seal having a lower sealing strength than the outer shell seal.

[0091] like Figure 4 As shown, the first shell 141 may include a first resin layer 141b disposed inside the first metal layer 141a. The first resin layer 141b may be a layer made of polypropylene (PP). The same applies to the second resin layer 142b to be described later. The first resin layer 141b requires high insulation performance and corrosion resistance, and the first resin layer 141b may be made of other resins that meet such requirements. The second shell 142 may also include a second resin layer 142b disposed inside the second metal layer 142a to face the first resin layer 141b.

[0092] like Figure 5 As shown, in a state where the first metal layer 141a and the second metal layer 142a are in direct contact with each other without the first resin layer 141b and the second resin layer 142b, the housing seal portion 132 can be formed by welding between the first metal layer 141a and the second metal layer 142a. When the metal layers are directly welded without the resin layer, the sealing strength of the housing seal portion 132 can be further enhanced.

[0093] like Figure 4As shown, the first shell 141 may include an outer resin layer 141c disposed on the outside of the first metal layer 141a. The second shell 142 may also include an outer resin layer 142c disposed on the outside of the second metal layer 142a. The outer resin layer may be a layer made of polyethylene terephthalate (PET). The outer resin layer needs to protect the secondary battery and also needs to electrically insulate the secondary battery, and the outer resin layer may be made of other resins that meet such requirements. However, if the outer resin layer interrupts the formation of the shell sealing portion by welding the metal layer, the outer resin layer may not be provided on at least a portion of the shell sealing portion.

[0094] Detailed structure of the exposed hole sealing part

[0095] like Figure 3 As shown, the secondary battery 100 according to this embodiment may further include an insulating film 170 disposed between the electrode lead 150 and each of the exposure hole shells 141 and 142, which are shells in which the exposure hole 133 is defined in the first shell 141 and the second shell 142. The insulating film 170 may be disposed only between the surface facing the exposure hole 133 of the two surfaces of the electrode lead 150 and the shell in which the exposure hole 133 is defined. The insulating film 170 may be disposed to surround the portion of the electrode lead 150 exposed by the exposure hole 133 (see Figure 2 For example, the insulating film 170 may be provided in the form of a rectangular frame. Figure 2 As shown, the exposure hole sealing portion 134 may be formed by welding between the insulating film 170 and the resin layer of the exposure hole housing 142 disposed to face the insulating film 170. One surface of the insulating film 170 may be combined with the resin layer of the exposure hole housing 142 to be sealed by welding, and the other surface thereof may be combined with the electrode lead 150 to be sealed by welding, bonding, or the like.

[0096] The surface treatment part 151 can be provided on the surface of the electrode lead 150 to improve the bondability with the insulating film 170. The same applies to another embodiment / modification to be described later. The surface treatment part 151 can be formed by performing mechanical treatment or chemical treatment on the surface of the electrode lead 150. Laser irradiation method, sandblasting method, etc. can be used as mechanical treatment. Alumina treatment, etching, etc. can be used as chemical treatment. These treatments can increase the surface roughness of the electrode lead 150.

[0097] like Figure 3As shown, the surface treatment portion 151 may be provided only on a partial area of ​​the surface of the electrode lead 150. The area provided with the surface treatment portion 151 may include an area of ​​the surface of the electrode lead 150 facing the insulating film 170. For example, the area provided with the surface treatment portion 151 may be provided as an area having a frame shape, which is an area formed when the insulating film 170 is projected onto the electrode lead 150. Alternatively, as Figure 3 As shown, the region where the surface treatment part 151 is provided may be provided as a region having a rectangular shape including a region formed when the insulating film 170 is projected onto the electrode lead 150 .

[0098] Example 2

[0099] Figure 6 is a perspective view showing a secondary battery according to Embodiment 2 of the present invention. Figure 7 yes Figure 6 . The secondary battery according to Example 2 is different from the secondary battery according to Example 1 in the structure of the accommodating portion. Hereinafter, the secondary battery according to Example 2 will be described focusing on this difference. For reference, the same details of the secondary battery according to Example 2 may be applied to the secondary battery according to Example 1 described above and the secondary battery according to the embodiment to be described later, as long as there is no conflict between them.

[0100] like Figure 7 As shown, the secondary battery 200 according to this embodiment may include an electrode assembly 110, a case 230, and an electrode lead 150. The electrode assembly 110 and the electrode lead 150 may be the same as those described above.

[0101] The housing 230 may include a housing portion 231 for housing the electrode assembly 110. The housing 230 may be a soft-pack housing. The housing 230 may be configured such that a first housing 241 and a second housing 242 disposed facing each other are sealedly combined with each other in a state where the electrode assembly 110 is housed. Here, the edge of the first housing 241 and the edge of the second housing 242 may be completely or partially sealed. The housing sealing portion 232 (see FIG. 2 ) to be described later may be formed by such sealing. Figure 6 Before the first outer case 241 is combined with the second outer case 242 , the receiving portion 231 of the outer case 230 may be pre-molded into a shape for receiving the electrode assembly 110 .

[0102] like Figure 6 As shown, the housing 230 may include an exposing hole 233 opened to expose at least a portion of the electrode lead 150 to the outside of the housing 230 .

[0103] The housing 230 may include an exposure hole sealing portion 234 disposed to surround the exposure hole 233. The exposure hole 233 may be defined in one or each of the first housing 241 and the second housing 242, and the exposure hole sealing portion 234 may be provided on a housing (exposure hole housing) in which the exposure hole 233 is defined.

[0104] The secondary battery 200 according to the embodiment may include an insulating film 170 (see FIG. 1 ) disposed between the electrode lead 150 and each of the exposure hole casings 241 and 242. Figure 7 ). The insulating film 170 may be the same as described above.

[0105] like Figure 7 As shown, the accommodation portion 231 according to this embodiment may include an electrode assembly accommodation portion 231a that accommodates the electrode assembly 110. The accommodation portion 231 may include an electrode lead accommodation portion 231b that accommodates at least a portion of the electrode lead 150. According to the shape of the accommodation portion 231, a portion of the electrode lead 150 may be accommodated in the electrode assembly accommodation portion 231a together with the electrode assembly 110, and another portion thereof may be accommodated in the electrode lead accommodation portion 231b.

[0106] The electrode lead 150 according to this embodiment may be disposed inside the housing 230 as described above. The electrode lead accommodating portion 231 b may also be disposed inside the housing 230 to correspond to the electrode lead 150. For example, Figure 7 As shown, the electrode lead receiving portion 231 b may be disposed inside the housing 230 without extending from the edge of the housing 230 .

[0107] The electrode lead 150 may be at least partially disposed in the housing seal 232 inside the housing 230 (see Figure 6 ). However, during the process of sealing the edge of the housing 230 to form the housing seal portion 232, when the electrode lead 150 is disposed between the first housing 241 and the second housing 242, the electrode lead 150 may apply force to the inside of the first housing 241 and the second housing 242 during sealing, thereby damaging the housings 241 and 242. For example, the first resin layer 141b and the second resin layer 142b of the housings 241 and 242 may be damaged (see Figure 4 ). In the housings 241 and 242 according to this embodiment, since the electrode lead 150 is accommodated in the electrode lead accommodating portion 231 b provided on the housing sealing portion 232 of the housings 241 and 242, the above-mentioned problem does not occur.

[0108] like Figure 7As shown, the side portion 231b1 of the electrode lead receiving portion 231b facing the electrode assembly receiving portion 231a may be in communication with the electrode assembly receiving portion 231a. The other side portions 231b2, 231b3, and 231b4 of the electrode lead receiving portion 231b may be surrounded by the housing sealing portion 232. Therefore, the electrode lead receiving portion 231b may be integrally sealed from the outside of the housing 230.

[0109] Before accommodating the electrode assembly 110, the electrode assembly accommodating portion 231a may be pre-molded into a shape for accommodating the electrode assembly 110. For example, the outer shell 230 having a film shape may be pressed to form the electrode assembly accommodating portion 231a. Before accommodating the electrode lead 150, the electrode lead accommodating portion 231b may also be pre-molded into a shape for accommodating the electrode lead 150. During the process of forming the electrode assembly accommodating portion 231a, or before or after the process, the electrode lead accommodating portion 231b may be formed by pressing the outer shell 230 having a film shape.

[0110] The electrode lead 150 may extend in a direction intersecting with the extending direction of the electrode tab 111 to be disposed inside the housing 230. Figure 7 As shown, the electrode lead 150 may be arranged in the extending direction of the electrode terminal tab 111 (see Figure 8 D1 in the vertical direction (see Figure 8 Here, the electrode lead accommodating portion 231b may be disposed to correspond to the direction in which the electrode lead 150 is disposed. When the electrode lead 150 is disposed as described above, the increase in the size of the housing 230 according to the disposition of the electrode lead 150 inside the housing 230 may be minimized.

[0111] Modification of Embodiment 2

[0112] The secondary battery according to Example 2 may be modified as follows. The same modification example may be applied to the secondary battery according to Example 1 except for the electrode lead accommodating portion.

[0113] Figure 8 It is shown Figure 7 Exploded perspective view of modification 1 of the secondary battery in. The electrode lead 250' according to modification 1 may extend in a direction (e.g., direction D2) intersecting with the extension direction D1 of the electrode terminal tab 111, and may be arranged so that the electrode terminal tab 111 is arranged in the middle part of the electrode lead 250' with the direction of intersection as a reference. The electrode lead accommodating portion 231b' may also be arranged to correspond to the electrode lead 250'. All exposure holes 233' may be arranged in the first housing 241.

[0114] Fig. 9 It is shown Figure 7Exploded perspective view of modification example 2 of the secondary battery in. The electrode terminal tab 111" according to modification example 2 can be bent toward a side S1 from which the electrode terminal tab 111" of the electrode assembly 110 protrudes, so that one side of the electrode lead 250" faces one side S1 of the electrode assembly 110. Due to this bending, the other side of the electrode lead 250" can be set to face a side S2 of the second shell 242 that defines the electrode assembly accommodating portion 231a". An exposure hole 233" can be set in a side S2 of the second shell 242 facing the other side of the electrode lead 250". The electrode lead accommodating portion 231b" can also be set in a side S2 of the second shell 242 to correspond to the exposure hole 233". For reference, Fig. 9 An example of a battery is shown in which the accommodation part 231 is provided only in the second case 242. When both the positive electrode tab and the negative electrode tab protrude from the same side of the electrode assembly, the exposure hole may also be defined on the same side of the case to correspond thereto.

[0115] Fig.10 It is shown Figure 7 1 is an exploded perspective view of a modified example 3 of a secondary battery in FIG. The electrode terminal tab 111″′ according to the modified example 3 may be bent toward the outermost surface S3 of the electrode assembly 110 so that one side of the electrode lead 250″′ is based on the direction of stacking the electrodes and the separator of the electrode assembly 110 (see Figure 8 Due to this bending, the other side of the electrode lead 250"' can be set to face the upper side S4 of the shell 242. The exposure hole 233"' can be set in the upper side S4 of the second shell 242 to which the other side of the electrode lead 250"' faces. The electrode lead accommodating portion 231b"' can also be set in the upper side S4 of the second shell 242 to correspond to the exposure hole 233"'. For reference, Fig.10 An example of a battery is shown in which the accommodation part 231 is provided only in the second case 242. When both the positive electrode tab and the negative electrode tab protrude from the same side of the electrode assembly, the exposure hole may also be defined in parallel with the upper side of the case to correspond thereto.

[0116] Fig.11 It is shown Figure 7 1 is an exploded perspective view of a modification 4 of a secondary battery in FIG. All electrode tabs 111″″ according to modification 4 may protrude from the same surface of the electrode assembly 110. For example, both the positive electrode tab and the negative electrode tab protrude from the same surface of the electrode assembly 110 and may be arranged to be spaced apart from each other. Fig.11 As shown, the electrode lead accommodating portion 231 b ″″ and the exposing hole 233 ″″ may be provided to correspond to the electrode tab.

[0117] Example 3

[0118] Fig.12 is a perspective view showing a secondary battery according to Embodiment 3 of the present invention. Fig.13 yes Fig.12 . The secondary battery according to Example 3 is different from the secondary battery according to Example 1 in the structure of the electrode lead. Hereinafter, the secondary battery according to Example 3 will be described focusing on this difference. For reference, the same details of the secondary battery according to Example 3 may be applied to the secondary batteries according to Examples 1 and 2 described above as long as there is no conflict therebetween.

[0119] like Fig.13 As shown, the secondary battery 300 according to this embodiment may include an electrode assembly 110, a case 330, and an electrode lead 350. The electrode assembly 110 may be the same as described above.

[0120] The housing 330 may include a housing portion 331 for housing the electrode assembly 110. The housing 330 may be a soft-pack housing. The housing 330 may be configured such that a first housing 341 and a second housing 342 facing each other are sealed to each other in a state where the electrode assembly 110 is housed. Here, the edge of the first housing 341 and the edge of the second housing 342 may be sealed in whole or in part. The housing sealing portion 332 (see Fig.12 ).

[0121] like Fig.12 As shown, the housing 330 may include an exposing hole 333 opened to expose at least a portion of the electrode lead 350 to the outside of the housing 330 .

[0122] The housing 330 may include an exposure hole sealing portion 334 disposed to surround the exposure hole 333 .

[0123] The secondary battery 300 according to this embodiment may include an insulating film 170 (see Fig.13 ).

[0124] like Fig.13 As shown, the accommodation portion 331 according to this embodiment may include an electrode assembly accommodation portion 331 a that accommodates the electrode assembly 110 . The accommodation portion 331 may include an electrode lead accommodation portion 331 b that accommodates at least a portion of the electrode lead 350 .

[0125] The electrode lead 350 according to this embodiment may be disposed inside the housing 230. An electrode lead accommodating portion 331b may also be disposed inside the housing 330 to correspond to the electrode lead 350.

[0126] In the following, reference will be made to Fig.14 The electrode lead 350 according to this embodiment is described in detail. Fig.14 It is along Fig.12 A cross-sectional view taken along line AA'.

[0127] The electrode lead 350 may include an exposed portion 350a and a non-exposed portion 350b. The exposed portion 350a is a portion of the electrode lead 350 exposed to the outside of the housing 342 through the exposure hole 333. The non-exposed portion 350b is another portion of the electrode lead 350 connected to the exposed portion 350a and covered by the housing 342 so as not to be exposed to the outside of the housing 342.

[0128] The exposed portion 350a may include a protrusion 350c protruding toward the outside of the housing 342 more than the non-exposed portion 350b. The protrusion 350c may protrude at least to the outer surface of the housing 342 (see P) more than the non-exposed portion 350b. Fig.14 A protrusion 350c is shown protruding from an outer surface of the housing 342 (see P).

[0129] like Fig.14 As shown, the protrusion 350c may be provided by pressing a portion of the exposed portion 350a. After a rectangular region is assumed in the electrode lead 350, the rectangular region may be pressed to provide Fig.13 Before pressing or during pressing, the two sides facing each other in the side portion of the rectangular area may also be cut. Alternatively, the electrode lead 350 may be bent into a shape such as Fig.14 The protrusion is provided by the cross-sectional shape shown. Alternatively, the protrusion can be formed by adding a separate component.

[0130] When the protrusion 350c is provided by pressing or bending the exposed portion 350a of the electrode lead 350, the protrusion 350c may be provided integrally with the non-exposed portion 350b which is the whole or a part of the exposed portion 350a. For example, the protrusion 350c may be a part of the exposed portion 350a extending as an integral part from the non-exposed portion 350b, and may also have a U-shaped cross-sectional shape by including a vertical extension extending toward the exposure hole 333 and a horizontal extension extending horizontally as an integral part from the vertical extension.

[0131] For reference, when the surface treatment portion is formed on the electrode lead 350 (see Figure 3 When the surface treatment portion 151 is formed, the surface treatment portion can be formed by performing laser etching on the surface of the electrode lead 350, welding the insulating film to the surface treatment portion, and then pressing or bending a portion of the electrode lead 350 into a U shape to form a protrusion 350c.

[0132] In order to electrically connect the electrode lead 350 to another part through the exposure hole 333, a part of the electrode lead 350 may protrude toward the outside of the shell 342, taking into account the thickness of the shell 342 and the like. Since the electrode lead 350 according to this embodiment includes a protrusion 350c protruding toward the outside of the shell 342, the electrode lead 350 can be easily electrically connected to another part. Even when the electrode lead 350 is welded to another part (e.g., a bus bar), the ease of welding can be increased. When the protrusion 350c protrudes from the non-exposed portion 350b at least to the outer surface of the shell 342 (see P), this ease can be further increased.

[0133] The protrusion 350c may be spaced apart from the edge of the exposure hole 333 by a predetermined distance L. Since the exposure hole 333 is defined therein, the metal layers 141a and 142a (see Figure 4 ) may protrude to one side of the exposure hole 333. However, when the metal layer of the housing 342 contacts the protrusion 350c of the electrode lead 350, an electrical short circuit may occur. In order to prevent the electrical short circuit, a spacing as described above may be required. The spacing L may be 0.5 mm or more. Alternatively, as Fig.15 As shown, in order to electrically insulate the protrusion 350c from the housing 342, an insulating member 380 may be disposed in the empty space defined by the above interval.

[0134] In the secondary battery according to Example 1, Fig.16 and Fig.17 In the embodiment, electrical insulation can be achieved without the protrusion 350c as described above.

[0135] In the secondary battery according to Embodiment 1, an exposure hole 133 for exposing the electrode lead 150 is defined in the outer case 130. Fig.16 The secondary battery is arranged such that the exposure holes 133 face each other as shown. Fig.17 When in close contact with each other as shown, the secondary batteries may be electrically connected to each other.

[0136] For example, Fig.16 As shown, the exposure hole defined on the front surface of the secondary battery can be arranged to correspond to the exposure hole defined on the rear surface of another secondary battery. Then, when the secondary battery is Fig.17 When stacked as shown, the secondary batteries may be electrically connected to each other.

[0137] Considering that the thickness of the outer shell is thin, the electrode leads can be in contact with each other only by close contact or stacking as described above. For stable contact of the electrode leads, a protrusion as described above can be provided on the electrode lead 150. Alternatively, a separate connecting member (not shown) can be further provided to electrically connect the electrode leads exposed by the exposure hole 133 to each other.

[0138] The description of the present invention is intended to be illustrative, and various changes and modifications may be made by one of ordinary skill in the art to which the present invention pertains without departing from the spirit and scope of the present invention as defined by the following claims.

[0139] Therefore, the embodiments described herein are used to describe the technical spirit of the present invention rather than to limit it. The scope of the technical spirit of the present invention is not limited by the embodiments.

[0140] Furthermore, the protection scope of the present invention should be determined by reasonable interpretation of the appended claims, and all technical concepts falling within the equivalent scope of the present application should be interpreted as being within the right scope of the present application.

Claims

1. A secondary battery comprising: An electrode assembly, the electrode assembly comprising an electrode terminal tab; a housing, the housing comprising a housing configured to accommodate the electrode assembly; as well as an electrode lead connected to the electrode terminal tab of the electrode assembly and disposed inside the housing, The housing further comprises an exposing hole opened to expose a portion of the electrode lead to the outside of the housing, Wherein, the electrode lead comprises: an exposed portion exposed to the outside of the housing through the exposure hole; and a non-exposed portion connected to the exposed portion and covered by the housing so as not to be exposed to the outside of the housing, The exposed portion includes a protruding portion that protrudes toward the outside of the housing more than the non-exposed portion.

2. The secondary battery according to claim 1, wherein The protruding portion protrudes at least to the outer surface of the housing more than the non-exposed portion.

3. The secondary battery according to claim 1, wherein The protrusion is spaced apart from an edge of the exposure hole by a predetermined distance. 4 . The secondary battery according to claim 3 , further comprising an insulating member disposed in an empty space provided by the interval for electrical insulation between the protrusion and the case.

5. The secondary battery according to claim 1, wherein The housing comprises: a housing seal configured to at least partially surround the receiving portion; and an exposure hole sealing portion configured to surround the exposure hole, Wherein, the housing sealing portion is more tightly sealed than the exposure hole sealing portion.

6. The secondary battery according to claim 5, wherein The housing seal is formed by welding, and The exposure hole sealing portion is formed by welding.

7. The secondary battery according to claim 1, wherein The housing also includes: a first housing, the first housing comprising a first metal layer; a second housing, the second housing being arranged to face the first housing so as to form the accommodation portion together with the first housing, the second housing comprising a second metal layer; a housing sealing portion configured to sealably couple the first housing and the second housing to each other and at least partially surround the accommodation portion; and An exposure hole sealing portion is provided on an exposure hole housing, which is a housing in which the exposure hole is defined, of the first housing and the second housing, and is configured to surround the exposure hole.

8. The secondary battery according to claim 7, wherein The housing sealing portion is formed by welding between the first metal layer and the second metal layer.

9. The secondary battery according to claim 7, wherein The first housing further includes a first resin layer disposed inside the first metal layer. The second housing further includes a second resin layer disposed inside the second metal layer and facing the first resin layer, and The housing sealing portion is formed by welding the first metal layer and the second metal layer in a state where the first metal layer and the second metal layer are in direct contact with each other without the first resin layer and the second resin layer.

10. The secondary battery according to claim 7, wherein Each of the first metal layer and the second metal layer includes stainless steel.

11. The secondary battery according to claim 7, further comprising an insulating film disposed between the exposure hole casing and the electrode lead to surround a portion of the electrode lead exposed through the exposure hole, in, The exposure hole sealing portion is formed by welding between the insulating film and a resin layer of the exposure hole housing disposed to face the insulating film.

12. The secondary battery according to claim 7, wherein The housing seal portion is provided to entirely surround the accommodation portion except for a portion where the first housing and the second housing are connected to each other, and The electrode lead is disposed inside the housing without passing through the housing sealing portion.

13. The secondary battery according to claim 1, wherein The electrode lead extends in a direction intersecting with an extending direction of the electrode tab and is disposed inside the housing.

14. The secondary battery according to claim 1, wherein The receiving portion comprises: an electrode assembly receiving portion configured to receive the electrode assembly; and An electrode lead accommodating portion is configured to accommodate at least a portion of the electrode lead.

15. The secondary battery according to claim 14, wherein Before accommodating the electrode assembly, the electrode assembly accommodating portion is pre-molded into a shape for accommodating the electrode assembly, and Before accommodating the electrode lead, the electrode lead accommodating portion is pre-molded into a shape for accommodating the electrode lead.

16. The secondary battery according to claim 1, wherein The electrode lead is provided to be electrically connected to an electrode lead of another secondary battery through the protrusion.

17. The secondary battery according to claim 7, further comprising an insulating film disposed between the exposure hole housing and the electrode lead to surround a portion of the electrode lead exposed through the exposure hole, in, A surface treatment portion for increasing the surface roughness is partially provided on the surface of the electrode lead. The region where the surface treatment portion is provided includes a region of the surface of the electrode lead that faces the insulating film.

18. A secondary battery comprising: An electrode assembly, the electrode assembly comprising an electrode terminal tab; a housing comprising a housing configured to house the electrode assembly; as well as an electrode lead connected to the electrode terminal tab of the electrode assembly and disposed inside the housing, The housing further includes an exposing hole opened to expose at least a portion of the electrode lead to the outside of the housing.

19. The secondary battery according to claim 18, wherein The electrode lead is disposed to be electrically connected to an electrode lead of another secondary battery through the exposure hole.

20. The secondary battery according to claim 18, wherein The electrode lead extends in a direction intersecting with an extending direction of the electrode tab and is disposed inside the housing such that the electrode tab is disposed at a middle portion of the electrode lead with reference to the intersecting direction.

21. The secondary battery according to claim 18, wherein The electrode tab is bent toward a side surface of the electrode assembly from which the electrode tab protrudes, so that one side surface of the electrode lead faces the one side surface of the electrode assembly.

22. The secondary battery according to claim 18, wherein The electrode tab is bent toward the outermost surface of the electrode assembly so that one side of the electrode lead faces the outermost surface of the electrode assembly based on a direction in which electrodes and a separator of the electrode assembly are stacked.

23. A secondary battery comprising: An electrode assembly, the electrode assembly comprising an electrode terminal tab; a housing comprising a housing configured to house the electrode assembly; as well as an electrode lead connected to the electrode terminal tab of the electrode assembly and disposed inside the housing, Wherein, the accommodation portion comprises: an electrode assembly receiving portion configured to receive the electrode assembly; and An electrode lead accommodating portion is configured to accommodate at least a portion of the electrode lead.

24. The secondary battery according to claim 23, wherein The housing further comprises a housing sealing portion configured to at least partially surround the receiving portion, The electrode lead accommodating portion is disposed on the outer shell sealing portion and inside the outer shell to accommodate the electrode lead.

25. The secondary battery according to claim 24, wherein A side of the electrode lead receiving portion facing the electrode assembly receiving portion is communicated with the electrode assembly receiving portion, and The remaining side of the electrode lead accommodating portion is surrounded by the housing sealing portion.

26. The secondary battery according to claim 23, wherein The housing further includes an exposure hole opened to expose at least a portion of the electrode lead to the outside of the housing.

27. The secondary battery according to claim 26, wherein: The electrode terminal tab is bent toward a side surface of the electrode assembly from which the electrode terminal tab protrudes, so that a side surface of the electrode lead faces the side surface of the electrode assembly, and The exposure hole is defined at one side surface of the case facing the other side surface of the electrode lead by bending of the electrode tab.

28. The secondary battery according to claim 26, wherein The electrode tab is bent toward the outermost surface of the electrode assembly so that one side of the electrode lead faces the outermost surface of the electrode assembly based on the direction in which the electrodes and the separator of the electrode assembly are stacked, and The exposure hole is defined at one side surface of the case facing the other side surface of the electrode lead by bending of the electrode tab.

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