Rechargeable battery and method of manufacturing rechargeable battery

Abstract

The present disclosure relates to a rechargeable battery and a method of manufacturing a rechargeable battery, the rechargeable battery comprising: an electrode assembly; and a case including: an accommodating portion at least partially surrounding the electrode assembly and formed of a first sheet disposed on an upper side of the electrode assembly in a thickness direction and a second sheet disposed on a lower side of the electrode assembly in the thickness direction; a sealing portion formed of the first sheet and the second sheet, connected to an edge of the accommodating portion, and bent to face a side surface of the accommodating portion, the sealing portion including an exhaust layer provided therein; and a cutout portion provided at one end portion of the sealing portion, in which the exhaust layer is provided on a bonding surface between the first sheet and the second sheet and contacts a corner portion of the accommodating portion and the cutout portion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0152966, filed in the Korean Intellectual Property Office on November 7, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a rechargeable battery, and more particularly, to a case of a pouch-type battery. Background Art

[0004] Rechargeable batteries are used for various purposes, such as power sources for small electronic devices (such as mobile phones or laptop computers), power sources for driving motors in transportation vehicles (such as electric vehicles or hybrid vehicles), etc. In the former case, pouch-type batteries are mainly used to facilitate miniaturization and slimness of small electronic devices. Summary of the Invention

[0005] The present disclosure provides a rechargeable battery capable of easily discharging internal gas under predetermined temperature and pressure conditions by having a venting function optimized for a sealing structure of a pouch-type battery.

[0006] A rechargeable battery according to an embodiment includes: an electrode assembly; and a shell, including: a accommodating portion, at least partially surrounding the electrode assembly, and formed by a first sheet and a second sheet, the first sheet being arranged on the upper side of the electrode assembly along the thickness direction, and the second sheet being arranged on the lower side of the electrode assembly along the thickness direction; a sealing portion, formed by the first sheet and the second sheet, connected to an edge of the accommodating portion, and bent to face a side surface of the accommodating portion, the sealing portion including a degassing layer provided in the sealing portion; a cutout portion, arranged at one end portion of the sealing portion, wherein the degassing layer is arranged on a bonding surface between the first sheet and the second sheet, and contacts a corner of the accommodating portion and the cutout portion.

[0007] The sealing portion may include a pair of first sealing portions, each of the pair of first sealing portions is arranged on a corresponding side of the accommodating portion, and each of the pair of first sealing portions may include a first portion facing the side surface of the accommodating portion and a second portion extending outward from the first portion.

[0008] The cutout portion may be provided at a corner of the second portion of the corresponding one of the pair of first sealing portions, and the degassing layer may be provided on the entire bonding surface of the second portion of the corresponding one of the pair of first sealing portions. The cutout portion may have any one of an arc shape and a straight line shape parallel to the oblique direction.

[0009] The cutout portion may be provided continuously across a corner portion of the second portion of the corresponding one of the pair of first sealing portions and a portion of the first portion, and the degassing layer may be provided continuously across the entire bonding surface of the second portion of the corresponding one of the pair of first sealing portions and a portion of the bonding surface of the first portion. The cutout portion may have any one of an arc shape and a straight line shape parallel to the oblique direction.

[0010] Each of the first sheet and the second sheet may include a polymer layer, and the melting point of the degassing layer may be lower than the melting point of the polymer layer. The degassing layer may be formed of a cast polypropylene layer having a coating layer stacked on an outer surface. The melting point of the coating layer may be 105° C. to 115° C.

[0011] The bonding strength between the degassing layer and at least one of the first sheet and the second sheet may be less than the bonding strength between the first sheet and the second sheet. The degassing layer may be formed of a cast polypropylene layer mixed with either a resin or a metal. The bonding strength of the degassing layer may be 0.5 kgf to 1.4 kgf.

[0012] A rechargeable battery according to another embodiment includes: an electrode assembly; and a case including: a housing portion at least partially surrounding the electrode assembly and formed by a first sheet and a second sheet, the first sheet being arranged on an upper side of the electrode assembly along a thickness direction, and the second sheet being arranged on a lower side of the electrode assembly along the thickness direction; and a sealing portion formed by the first sheet and the second sheet, connected to an edge of the housing portion, and including a degassing layer provided in the sealing portion. The sealing portion includes a first portion facing a side surface of the housing portion due to bending the sealing portion, and a second portion extending outward from the first portion. The case further includes a cutout portion provided at a corner of the second portion, and the degassing layer is provided on a bonding surface of the second portion and contacts the corner of the housing portion and the cutout portion.

[0013] The cutout portion may have any one of an arc shape and a straight line shape parallel to the oblique direction. The cutout portion may be continuously provided across the corner of the second portion and a portion of the first portion, and the degassing layer may be continuously provided across a joining surface of the second portion and a portion of the joining surface of the first portion to contact the entire cutout portion and a portion of the edge of the accommodating portion.

[0014] The degassing layer may be formed of a cast polypropylene layer having a coating layer stacked on an outer surface thereof or a cast polypropylene layer mixed with any one of a resin and a metal.

[0015] According to some embodiments, a method for manufacturing a rechargeable battery is provided. The method may include: forming a case for an electrode assembly; and disposing the electrode assembly inside the case; wherein the case includes: a housing portion at least partially surrounding the electrode assembly and formed by a first sheet and a second sheet, the first sheet being disposed on an upper side of the electrode assembly along a thickness direction, and the second sheet being disposed on a lower side of the electrode assembly along the thickness direction; a sealing portion formed by the first sheet and the second sheet, connected to an edge of the housing portion and bent to face a side surface of the housing portion, the sealing portion including a degassing layer provided in the sealing portion; and a cutout portion disposed at one end portion of the sealing portion, wherein the degassing layer is disposed on a bonding surface between the first sheet and the second sheet and contacts a corner of the housing portion and the cutout portion.

[0016] In some embodiments, the sealing portion includes a pair of first sealing portions, each of the pair of first sealing portions is arranged on a corresponding side of the accommodating portion, and each of the pair of first sealing portions includes a first portion facing the side surface of the accommodating portion and a second portion extending outward from the first portion.

[0017] In some embodiments, the cutout portion is provided at a corner of the second portion of a corresponding one of the pair of first sealing portions, and the degassing layer is provided on the entire bonding surface of the second portion of the corresponding one of the pair of first sealing portions.

[0018] In some embodiments, the cutout portion has any one of an arc shape and a straight line shape parallel to the oblique direction.

[0019] According to the embodiment, the overall size of the rechargeable battery can be reduced by bending the sealing portion, and the safety of the rechargeable battery can be improved by using the cutout portion and the venting layer. Since the cutout portion shortens the distance that internal gas moves from the corner of the receiving portion through the venting layer, the cutout portion can facilitate gas discharge, allowing internal pressure to be quickly released. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a perspective view of a rechargeable battery according to a first embodiment.

[0021] Figure 2 It is along Figure 1 sectional view of the rechargeable battery taken along line II-II.

[0022] Figure 3 yes Figure 2 A partially enlarged view of an electrode assembly of a rechargeable battery is shown in FIG.

[0023] Figure 4 It shows Figure 2 FIG. 4 is a view showing a state before the first sealing portion of the rechargeable battery is bent.

[0024] Figure 5 yes Figure 1 A front view of a first sealing portion of a rechargeable battery is shown in FIG.

[0025] Figure 6 is a partial plan view of a rechargeable battery, showing Figure 5 FIG. 4 shows a state before the first sealing portion of the rechargeable battery is bent.

[0026] Figure 7 It is from Figure 5 Observed from the direction A Figure 5 A view of the first sealing portion of a rechargeable battery.

[0027] Figure 8A and Figure 8B yes Figure 7 A partially enlarged view of a first sealing portion and a venting layer of a rechargeable battery is shown in FIG.

[0028] Figure 9 is a front view of a first sealing portion of a rechargeable battery according to a second embodiment.

[0029] Figure 10 yes Figure 9 A partial plan view of a rechargeable battery showing Figure 9 FIG. 4 shows a state before the first sealing portion of the rechargeable battery is bent.

[0030] Figure 11is a front view of a first sealing portion of a rechargeable battery according to a third embodiment.

[0031] Figure 12 yes Figure 11 A partial plan view of a rechargeable battery showing Figure 11 FIG. 4 shows a state before the first sealing portion of the rechargeable battery is bent.

[0032] Figure 13 is a front view of a first sealing portion of a rechargeable battery according to a fourth embodiment.

[0033] Figure 14 yes Figure 13 A partial plan view of a rechargeable battery showing Figure 13 FIG. 4 shows a state before the first sealing portion of the rechargeable battery is bent. DETAILED DESCRIPTION

[0034] Hereinafter, the embodiments of the present disclosure will be described more fully with reference to the accompanying drawings so that those skilled in the art can easily implement these embodiments. The present disclosure can be modified in various different ways, all without departing from the spirit or scope of the present disclosure.

[0035] The internal temperature and internal pressure of a rechargeable battery may increase rapidly due to various reasons, such as rapid charging, internal short circuit, external shock, exposure to a high temperature environment, etc. The rechargeable battery described herein has a venting function for discharging internal gas under preset temperature and pressure conditions to prevent combustion and / or explosion due to the increase in temperature and pressure.

[0036] Figure 1 is a perspective view of a rechargeable battery according to a first embodiment, Figure 2 It is along Figure 1 sectional view of the rechargeable battery taken along line II-II. Figure 3 yes Figure 2 A partially enlarged view of an electrode assembly of a rechargeable battery shown in FIG. Figure 4 It shows Figure 2 FIG. 4 is a view showing a state before the first sealing portion of the rechargeable battery is bent.

[0037] refer to Figures 1 to 4 The rechargeable battery 100 according to the present embodiment may include an electrode assembly 120 and a case 130 that accommodates and seals the electrode assembly 120 together with an electrolyte. The case 130 may be referred to as a pouch and may include a cutout portion 70 and a vent layer 80 to be described later.

[0038] The electrode assembly 120 may include a first electrode 10 and a second electrode 20, which are provided with a separator 30 interposed therebetween. The first electrode 10 may include a first substrate 11, a first composite layer 12 provided on both surfaces of the first substrate 11 (e.g., a first composite layer 12 and a second composite layer 12 provided on both surfaces of the first substrate 11), and a substrate extending from the first substrate 11 to one side (e.g., along the Figure 1 The first electrode tab 13 is shown in the longitudinal axis or direction "L" in FIG. The second electrode 20 may include a second substrate 21, a second composite layer 22 disposed on both surfaces of the second substrate 21 (for example, a first second composite layer 22 and a second second composite layer 22 disposed on respective surfaces of the second substrate 21), and a second composite layer 22 extending from the second substrate 21 to one side (for example, along Figure 1 The second electrode tab 23 is shown in the longitudinal axis or direction "L").

[0039] In lithium-ion batteries, the first substrate 11 may be formed of aluminum foil, and the first composite layer 12 may include a transition metal oxide (such as LiCoO2, LiNiO2, LiMn2O4, Li(NiCoAl)O2, LiFePO4, Li(NiCoMn)O2, etc.), a conductive material, a binder, etc. The second substrate 21 may be formed of copper foil or nickel foil, and the second composite layer 22 may include graphite, a conductive material, a binder, etc. The first electrode 10 may be referred to as a positive electrode, and the second electrode 20 may be referred to as a negative electrode.

[0040] The separator 30 may include a polymer material such as polyethylene (PE), polypropylene (PP), etc., and may insulate the first electrode 10 and the second electrode 20 while allowing movement of lithium ions.

[0041] The electrode assembly 120 may be configured to be flattened after the first electrode 10, the separator 30, and the second electrode 20 are wound around two winding axes, and may be a wound-type electrode assembly. The electrode assembly 120 may have a configuration in which a plurality of first electrodes 10 and a plurality of second electrodes 20 are alternately stacked one after another with the separator 30 interposed therebetween, and may be a stacked-type electrode assembly. In the latter case, a plurality of separators separated individually may be used, or one separator folded in a zigzag pattern may be used. Figure 2 , a case where the electrode assembly 120 has a wound type is illustrated as an example.

[0042] The electrode assembly 120 may have a rectangular shape in a plane, with a pair of long sides (e.g., extending along a length axis or direction "L") and a pair of short sides (e.g., extending along a width axis or direction "W"). Hereinafter, the phrase "in a plane" may mean when viewing the target portion from above.

[0043] In this embodiment, a direction parallel to the long side of the electrode assembly 120 may be referred to as a length direction L of the rechargeable battery, and a direction parallel to the short side of the battery assembly 120 may be referred to as a width direction W of the rechargeable battery. A direction orthogonal to the length direction L and the width direction W may be referred to as a thickness direction T of the rechargeable battery. The first electrode tab 13 and the second electrode tab 23 may extend from one short side of the electrode assembly 120 along the length direction L, and the first electrode tab 13 and the second electrode tab 23 may be disposed at a distance from each other along the width direction W.

[0044] The case 130 may include a first sheet 40 and a second sheet 50 respectively provided on the sides (upper and lower sides) of the electrode assembly 120 along the thickness direction T. For example, the first sheet 40 may be provided on the upper side of the electrode assembly 120, and the second sheet 50 may be provided on the lower side of the electrode assembly 120. Each of the first sheet 40 and the second sheet 50 may be formed of a composite sheet and may have an area larger than that of the electrode assembly 120 in a plane. One of the first sheet 40 and the second sheet 50 (e.g., the first sheet 40) may have a concave portion 45 capable of accommodating the electrode assembly 120. The concave portion 45 may be formed by press forming.

[0045] The composite sheet may have a three-layer structure including a first polymer layer, a metal layer, and a second polymer layer. The metal layer may include aluminum and may provide mechanical strength to the housing 130. The polymer layer may include any one of modified polypropylene (PP), polyethylene terephthalate (PET), nylon, and / or PET-nylon and may provide insulation and protection to the housing 130.

[0046] After the electrode assembly 120 is accommodated in the concave portion 45 of the first sheet 40, the edges of the first sheet 40 and the second sheet 50 may be integrally combined by heat welding (or heat fusion). The housing 130 may include a housing portion 131 that accommodates the electrode assembly 120 and a sealing portion 132 connected to the edge of the housing portion 131. In one embodiment, the housing portion 131 may at least partially surround the electrode assembly 120. The central portion of the first sheet 40 and the second sheet 50 surrounding the electrode assembly 120 may form the housing portion 131, and the edge portion of the first sheet 40 and the second sheet 50 that is integrally combined by heat welding may form, for example, a sealing portion 132. For example, the sealing portion 132 may be formed by the combined body of the first sheet 40 and the second sheet 50.

[0047] The sealing portion 132 may include a pair of first sealing portions 133 parallel to the length direction L and a pair of second sealing portions 134 parallel to the width direction W. The first electrode tab 13 and the second electrode tab 23 may pass through either of the second sealing portions 134 to protrude outside the housing 130 and may function as electrode terminals for supplying current to an external device. The first electrode tab 13 and the second electrode tab 23 may overlap with the second sealing portion 134 at a portion surrounded by the protective tape 60.

[0048] The first sealing portion 133 may be bent to face the side surface of the receiving portion 131 to reduce the overall size of the rechargeable battery 100. Figure 4 As shown, the initial first sealing portion 133 can be arranged parallel to the upper and lower surfaces of the electrode assembly 120. This may increase the overall size of the rechargeable battery. Since the overall size of the rechargeable battery must be reduced in order to reduce the size of the electronic device, the first sealing portion 133 can be bent to be arranged parallel to the side surface of the receiving portion 131 (for example, parallel to the thickness direction "T").

[0049] If the first sheet 40 having the concave portion 45 is provided, the first sealing portion 133 may be disposed at substantially the same height as the second sheet 50 before the first sealing portion 133 is bent. Figure 4 The position shown in FIG is vertically bent upward to be arranged parallel to the side surface of the electrode assembly 120.

[0050] Similar to the first sealing portion 133 , the second sealing portion 134 of the pair of second sealing portions 134 , disposed opposite the first and second electrode tabs 13 and 23 , may be vertically bent to face a side surface of the accommodating portion 131 .

[0051] Figure 5 yes Figure 1 A front view of a first sealing portion of a rechargeable battery is shown in FIG. Figure 6 yes Figure 5 A partial plan view of a rechargeable battery showing Figure 5 FIG. 4 shows a state before the first sealing portion of the rechargeable battery is bent. Figure 7 It is from Figure 5 Observed from the direction A Figure 5 A view of the first sealing portion of a rechargeable battery.

[0052] refer to Figures 5 to 7 , the length of the first sealing portion 133 along the length direction L may be greater than the length of the accommodating portion 131. One end portion ( Figure 5The left end portion in the longitudinal direction L may be disposed at a predetermined distance from the accommodating portion 131. The first sealing portion 133 may include a first portion 133a facing the accommodating portion 131 along the width direction W and a second portion 133b that does not face the accommodating portion 131 along the width direction W (e.g., because the second portion 133b extends beyond the accommodating portion 131 along the length direction L). The second portion 133b may be referred to as an extension portion. In one embodiment, the second portion 133b may extend outward from the first portion 133a.

[0053] The cutout portion 70 may be provided at the second portion 133b. In a typical rechargeable battery, the first sealing portion may generally have a rectangular shape, and the corners of the second portion may be folded inward. However, in the rechargeable battery 100 of this embodiment, the corners of the second portion 133b may be cut by mechanical cutting, laser cutting, etc., and the cutout portion 70 may be provided along the cutout portion.

[0054] The cutout portion 70 may be formed in an arc shape having a predetermined curvature. Figure 5 As shown, the cutout portion 70 may have a convex curve toward the lower end of the first sealing portion 133. Just as the corners of the second portion 133b are folded inward, the arc-shaped cutout portion 70 can prevent the end portion of the first sealing portion 133 from protruding, thereby facilitating the connection between the housing 130 and the protective circuit when the protective circuit (such as a protective circuit module (PCM)) is connected to the housing 130.

[0055] In one embodiment, the cutout portion 70 may be provided at one end portion of the sealing portion 132. The cutout portion 70 may be provided at a predetermined distance from the lower end of the bent first sealing portion 133 along the thickness direction T. For example, one end portion of the cutout portion 70 close to the accommodating portion 131 may contact the upper end of the first sealing portion 133, and the other end of the cutout portion 70 away from the accommodating portion 131 may have a height h from the lower end of the first sealing portion 133.

[0056] The degassing layer 80 may be provided on the bonding surface of the second portion 133b to contact the corner of the cutout portion 70 and the accommodating portion 131. The bonding surface of the second portion 133b may be the bonding surface between the first sheet 40 and the second sheet 50, and the degassing layer 80 may be provided between the first sheet 40 and the second sheet 50 at the second portion 133b.

[0057] When manufacturing the first sheet 40 and the second sheet 50, the degassing layer 80 may be provided on at least one of the inner surface of the first sheet 40 and the inner surface of the second sheet 50 corresponding to the second portion 133b, taking into account the position of the cutout portion 70. The degassing layer 80 may be bonded to at least one of the inner surface of the first sheet 40 and the inner surface of the second sheet 50 by various methods, such as adhesive bonding, heat fusion, welding, etc. The degassing layer 80 may be provided on the entire bonded surface of the second portion 133b.

[0058] The degassing layer 80 may have a lower degree of bonding than the degree of bonding between the first sheet 40 and the second sheet 50 by heat welding, or may have a lower melting point than the melting point of the polymer layer included in the first sheet 40 and the second sheet 50. The degassing layer 80 may have both a lower degree of bonding than the degree of bonding between the first sheet 40 and the second sheet 50 and a lower melting point than the melting point of the polymer layer included in the first sheet 40 and the second sheet 50.

[0059] For example, the degree of bonding of the degassing layer 80 may refer to the degree of bonding between the degassing layer 80 and the first sheet 40 or the second sheet 50, or the degree of bonding between the two degassing layers when the degassing layer 80 is provided on each of the inner surfaces of the first sheet 40 and the inner surfaces of the second sheet 50 to be bonded to each other. Bonding degree may have the same meaning as bonding strength. The degassing layer 80 may include any one of a polymer resin layer and a polymer resin-metal hybrid layer that meet the above conditions.

[0060] Figure 8A and Figure 8B yes Figure 7 A partial enlarged view of the first sealing portion and the exhaust layer is shown in FIG.

[0061] refer to Figure 8A The degassing layer 80 may include a cast polypropylene (CPP) layer 81 and a coating layer 82 provided on the outer surface of the cast polypropylene layer 81. The coating layer 82 may be a resin layer including polyethylene (PE) or the like, or a metal layer including aluminum (Al), copper (Cu), or the like. The melting point of the coating layer 82 may be approximately 100° C. to 120° C., and as another example, may be approximately 105° C. to 115° C. This temperature range may be lower than the melting point of the polymer layer 41 of the first sheet 40 and the polymer layer 51 of the second sheet 50, which may be approximately 140° C. to 165° C.

[0062] refer to Figure 8BThe degassing layer 80 may be formed of a cast polypropylene (CPP) layer mixed with a resin (such as polyethylene (PE) or a metal (such as aluminum (Al) or copper (Cu)). The first sheet 40 and the second sheet 50 may be bonded at a temperature of approximately 180°C to 230°C and for a time of 1 to 5 seconds. In this case, the bonding strength between the first sheet 40 and the second sheet 50 may be approximately 1.5 kgf or greater. The bonding strength of the degassing layer 80 may be approximately 0.5 kgf to 1.4 kgf. This bonding strength range may be lower than the bonding strength between the first sheet 40 and the second sheet 50.

[0063] For reference, in Figure 8A and Figure 8B , reference numeral 42 may denote a metal layer included in the first sheet 40 , and reference numeral 52 may denote a metal layer included in the second sheet 50 .

[0064] Generally, the internal temperature of a rechargeable battery may increase due to various reasons such as overcharging, internal short circuit, external impact, exposure to a high temperature environment, etc. In this case, gas may be generated due to evaporation of the electrolyte, etc. The generation of gas may cause an increase in the internal pressure of the rechargeable battery and may cause combustion and / or explosion of the rechargeable battery.

[0065] Return Reference Figures 5 to 7 , the degassing layer 80 may melt under a specific temperature condition to open the bonding surface, or may release the bond under a specific pressure condition to open the bonding surface.

[0066] For example, the surface of the exhaust layer 80 (e.g., Figure 8A The coating 82 may melt at a specific temperature or higher, thereby creating a gap between the first and second sheets 40, 50 and the venting layer 80. In some embodiments, if the pressure applied to the venting layer 80 becomes greater than the degree of bonding of the venting layer 80, the venting layer 80 may be torn from the first and second sheets 40, 50, or the venting layer 80 may be destroyed, thereby creating a gap between the first and second sheets 40, 50 and the venting layer 80 or within the venting layer 80.

[0067] The internal gas of the rechargeable battery 100 can reach the cutout portion 70 from the corner 131a of the receiving portion 131 through a gap formed around or inside the exhaust layer 80, and can be quickly discharged to the outside through the opened cutout portion 70. Figure 6 , a moving direction of internal gas passing through the degassing layer 80 is indicated by an arrow. When the internal pressure of the rechargeable battery 100 increases, the degassing layer 80 may release the internal pressure by opening the bonding surface.

[0068] The rechargeable battery 100 of this embodiment can reduce the overall size by bending the first sealing portion 133, and can simultaneously improve safety by including the venting layer 80 at the second portion 133b of the first sealing portion 133. For example, the cutout portion 70 can shorten the distance that internal gas moves from the corner 131a of the accommodating portion 131 through the venting layer 80, thereby facilitating rapid gas discharge to enable rapid release of internal pressure.

[0069] If the cutout portion 70 is not provided in the second portion 133b and the exhaust layer 80 is provided on the entire bonding surface of the second portion 133b, the internal gas may be exhausted to the outside only by moving from the corner 131a of the accommodating portion 131 along a path corresponding to the width of the first sealing portion 133 or from the corner 131a of the accommodating portion 131 along an oblique path to the corner of the second portion 133b. This configuration may hinder the rapid exhaust of the internal gas.

[0070] In this embodiment, the distance between the corner 131a of the receiving portion 131 and the edge of the exhaust layer 80 can be shortened by the cutout portion 70, so that the cutout portion 70 enables rapid exhaust of gas. For example, the rechargeable battery 100 of this embodiment can quickly release internal pressure in an abnormal situation where the internal temperature and internal pressure rise rapidly, and can effectively prevent the rechargeable battery from burning and / or exploding.

[0071] Figure 9 is a front view of a first sealing portion of a rechargeable battery according to a second embodiment, Figure 10 is a partial plan view of a rechargeable battery, showing Figure 9 The state before the first sealing portion of the rechargeable battery is bent is shown in FIG. The rechargeable battery of the second embodiment may have a configuration that is the same as or similar to that of the first embodiment described above except for the contents described below.

[0072] refer to Figure 9 and Figure 10 In the second embodiment, the cutout portion 71 may be provided across the first portion 133a and the second portion 133b of the first sealing portion 133, and the degassing layer 80 may be provided across the entire bonding surface of the second portion 133b and a portion of the bonding surface of the first portion 133a to contact the corner 131a of the accommodating portion 131 and the cutout portion 71. The length L1 of the cutout portion 71 along the length direction L of the rechargeable battery may be greater than the length L2 of the second portion 133b, and a portion of the degassing layer 80 may face the side surface of the accommodating portion 131 along the width direction W of the rechargeable battery.

[0073] In the second embodiment, the degassing layer 80 may contact not only the corner 131a of the receiving portion 131 but also a portion of the edge 131b of the receiving portion 131 parallel to the length direction L. In this structure, when the temperature and pressure of the rechargeable battery increase, the degassing layer 80 may be quickly melted or damaged to quickly open the bonding surface. As a result, the internal pressure can be released more quickly.

[0074] In the second embodiment, the length of the exhaust layer 80 in contact with the accommodating portion 131 can be extended, and the path for the internal gas to move from the accommodating portion 131 through the exhaust layer 80 can be shortened, compared to the first embodiment. Figure 10 , the movement direction of the internal gas through the degassing layer 80 is indicated by an arrow. In the second embodiment, when the temperature and pressure of the rechargeable battery increase, the opening of the bonding surface of the degassing layer 80 and the gas discharge due to the opening can be performed more effectively.

[0075] Figure 11 is a front view of a first sealing portion of a rechargeable battery according to a third embodiment, Figure 12 yes Figure 11 A partial plan view of a rechargeable battery showing Figure 11 The state before the first sealing portion of the rechargeable battery is bent is shown in FIG. The rechargeable battery of the third embodiment may have a configuration that is the same as or similar to that of the first embodiment described above except for the contents described below.

[0076] refer to Figure 11 and Figure 12 In the third embodiment, the cutout portion 72 may have a straight line shape, and the exhaust layer 80 may be provided on the bonding surface of the second portion 133b to contact the corner 131a of the accommodating portion 131 and the cutout portion 72. The corner of the second portion 133b may be cut into a straight line along an oblique direction, and the cutout portion 72 having a straight line shape may be provided along the cutout portion. For example, based on Figure 10 The oblique direction may be a direction inclined with respect to the lower end and the left and right side surfaces of the second portion 133b.

[0077] Figure 13 is a front view of a first sealing portion of a rechargeable battery according to a fourth embodiment, Figure 14 yes Figure 13 A partial plan view of a rechargeable battery showing Figure 13 The state before the first sealing portion of the rechargeable battery is bent is shown in FIG. The rechargeable battery of the fourth embodiment may have a configuration that is the same as or similar to that of the third embodiment described above except for the contents described below.

[0078] refer to Figure 13 and Figure 14 In the fourth embodiment, the cutout portion 73 may be provided across the first portion 133a and the second portion 133b of the first sealing portion 133, and the degassing layer 80 may be provided across the entire bonding surface of the second portion 133b and a portion of the bonding surface of the first portion 133a to contact the corner 131a of the accommodating portion 131 and the cutout portion 73. The length L3 of the cutout portion 73 along the length direction L of the rechargeable battery may be greater than the length L4 of the second portion 133b, and a portion of the degassing layer 80 may face the side surface of the accommodating portion 131 along the width direction W of the rechargeable battery.

[0079] In the fourth embodiment, the degassing layer 80 can contact not only the corner 131a of the accommodating portion 131, but also a portion of the edge 131b of the accommodating portion 131 parallel to the length direction L. In the fourth embodiment, the length of contact between the degassing layer 80 and the accommodating portion 131 can be extended, and the path of internal gas moving from the accommodating portion 131 through the degassing layer 80 can be shortened compared to the third embodiment. Therefore, when the temperature and internal pressure of the rechargeable battery increase, the opening of the bonding surface of the degassing layer 80 and the gas discharge caused by the opening can be performed more effectively.

[0080] According to some embodiments, a method for manufacturing a rechargeable battery is provided. The method may include forming a case for an electrode assembly; and disposing the electrode assembly inside the case; wherein the case includes: a housing portion at least partially surrounding the electrode assembly and formed of a first sheet and a second sheet; a sealing portion formed of a first sheet and a second sheet, the first sheet being disposed on an upper side of the electrode assembly along a thickness direction, the second sheet being disposed on a lower side of the electrode assembly along a thickness direction, connected to an edge of the housing portion, and bent to face a side surface of the housing portion, the sealing portion including a degassing layer provided in the sealing portion; and a cutout portion disposed at one end portion of the sealing portion, wherein the degassing layer is disposed on a bonding surface between the first sheet and the second sheet and contacts a corner of the housing portion and the cutout portion.

[0081] In some embodiments, the sealing portion includes a pair of first sealing portions, each of the pair of first sealing portions is arranged on a corresponding side of the accommodating portion, and each of the pair of first sealing portions includes a first portion facing the side surface of the accommodating portion and a second portion extending outward from the first portion.

[0082] In some embodiments, the cutout portion is provided at a corner of the second portion of the corresponding one of the pair of first sealing portions, and the degassing layer is provided on the entire bonding surface of the second portion of the corresponding one of the pair of first sealing portions.

[0083] In some embodiments, the cutout portion has any one of an arc shape and a straight line shape parallel to the oblique direction.

[0084] While the present disclosure has been described in conjunction with what are presently considered to be practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A rechargeable battery comprising: Electrode assembly; as well as The housing comprises: an accommodating portion at least partially surrounding the electrode assembly and formed by a first sheet and a second sheet, the first sheet being disposed on an upper side of the electrode assembly along a thickness direction, and the second sheet being disposed on a lower side of the electrode assembly along the thickness direction; a sealing portion formed of the first sheet and the second sheet, connected to an edge of the accommodating portion, and bent to face a side surface of the accommodating portion, the sealing portion including a degassing layer provided in the sealing portion; and a cutout portion provided at one end portion of the sealing portion, wherein: The degassing layer is disposed on a bonding surface between the first sheet and the second sheet, and contacts a corner of the accommodating portion and the cutout portion.

2. The rechargeable battery according to claim 1, wherein: The sealing portion includes a pair of first sealing portions, each of which is disposed on a corresponding side of the accommodating portion, and Each of the pair of first sealing portions includes a first portion facing the side surface of the accommodating portion and a second portion extending outwardly from the first portion.

3. The rechargeable battery according to claim 2, wherein: The cutout portion is provided at a corner portion of the second portion of a corresponding one of the pair of first sealing portions, and The exhaust layer is provided on the entire bonding surface of the second portion of a corresponding one of the pair of first seal portions.

4. The rechargeable battery according to claim 3, wherein: The cutout portion has any one of an arc shape and a straight line shape parallel to an oblique direction.

5. The rechargeable battery according to claim 2, wherein: The cutout portion is provided continuously across a corner portion of the second portion of a corresponding one of the pair of first seal portions and a portion of the first portion, and The degassing layer is provided continuously across an entire bonding surface of the second portion and a portion of a bonding surface of the first portion of a corresponding one of the pair of first sealing portions.

6. The rechargeable battery according to claim 5, wherein: The cutout portion has any one of an arc shape and a straight line shape parallel to an oblique direction.

7. The rechargeable battery according to claim 1, wherein: Each of the first sheet and the second sheet comprises a polymer layer; and The melting point of the exhaust layer is lower than the melting point of the polymer layer.

8. The rechargeable battery according to claim 7, wherein: The degassing layer is formed of a cast polypropylene layer with a coating layer stacked on the outer surface.

9. The rechargeable battery according to claim 8, wherein: The melting point of the coating is 105°C to 115°C.

10. The rechargeable battery according to claim 1, wherein: A bonding strength of the exhaust layer to at least one of the first sheet and the second sheet is smaller than a bonding strength between the first sheet and the second sheet.

11. The rechargeable battery according to claim 10, wherein: The degassing layer is formed of a cast polypropylene layer mixed with any one of a resin and a metal.

12. The rechargeable battery according to claim 11, wherein: The bonding strength of the exhaust layer is 0.5 kgf to 1.4 kgf.

13. A rechargeable battery comprising: Electrode assembly; as well as The housing comprises: an accommodating portion at least partially surrounding the electrode assembly and formed by a first sheet and a second sheet, the first sheet being disposed on an upper side of the electrode assembly along a thickness direction and the second sheet being disposed on a lower side of the electrode assembly along the thickness direction; and a sealing portion formed by the first sheet and the second sheet, connected to an edge of the accommodating portion, and comprising a degassing layer provided in the sealing portion; and wherein: The sealing portion includes a first portion facing the side surface of the accommodating portion due to bending the sealing portion and a second portion extending outward from the first portion; The housing further includes a cutout portion disposed at a corner of the second portion; and The degassing layer is disposed on a bonding surface of the second portion and contacts a corner of the receiving portion and the cutout portion.

14. The rechargeable battery according to claim 13, wherein: The cutout portion has any one of an arc shape and a straight line shape parallel to an oblique direction.

15. The rechargeable battery according to claim 13, wherein: The cutout portion is provided continuously across the corner of the second portion and a portion of the first portion, and The degassing layer is continuously provided across a bonding surface of the second portion and a portion of a bonding surface of the first portion to contact the entirety of the cutout portion and a portion of the edge of the receiving portion.

16. The rechargeable battery according to claim 13, wherein: The degassing layer is formed of a cast polypropylene layer having a coating layer stacked on an outer surface or a cast polypropylene layer mixed with any one of a resin and a metal.

17. A method of manufacturing a rechargeable battery, comprising: forming a casing for the electrode assembly; as well as Disposing the electrode assembly inside the housing; The housing comprises: an accommodating portion at least partially surrounding the electrode assembly and formed by a first sheet and a second sheet, the first sheet being disposed on an upper side of the electrode assembly along a thickness direction, and the second sheet being disposed on a lower side of the electrode assembly along the thickness direction; a sealing portion formed of the first sheet and the second sheet, connected to an edge of the accommodating portion, and bent to face a side surface of the accommodating portion, the sealing portion including a degassing layer provided in the sealing portion; and a cutout portion provided at one end portion of the sealing portion, wherein: The degassing layer is disposed on a bonding surface between the first sheet and the second sheet, and contacts a corner of the accommodating portion and the cutout portion.

18. The method of claim 17, wherein: The sealing portion includes a pair of first sealing portions, each of which is disposed on a corresponding side of the accommodating portion, and Each of the pair of first sealing portions includes a first portion facing the side surface of the accommodating portion and a second portion extending outwardly from the first portion.

19. The method of claim 18, wherein: The cutout portion is provided at a corner portion of the second portion of a corresponding one of the pair of first sealing portions, and The exhaust layer is provided on the entire bonding surface of the second portion of a corresponding one of the pair of first seal portions.

20. The method of claim 19, wherein: The cutout portion has any one of an arc shape and a straight line shape parallel to an oblique direction.

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