Secondary battery including side insulator

Abstract

The present disclosure discloses a secondary battery. According to the present disclosure, there is provided a secondary battery comprising: a case in which an electrode assembly is accommodated; the cover plate comprises an exhaust port, and the cover plate seals the opening of the shell; and a side insulator disposed at a lower portion of the cover plate, the side insulator including: an exhaust port cover portion including a main chamber and disposed at a lower portion of the exhaust port; and an assembly bracket on which the exhaust port cover part is arranged. The present disclosure may protect an exhaust port from instantaneous pressure changes and the like by an exhaust port cover portion provided on a side insulator.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery. Background Art

[0002] A secondary battery is one of energy storage devices that can be charged and discharged. Secondary batteries are widely used in various devices that use electricity as a power source. For example, secondary batteries are used as energy storage devices in various devices from small devices such as mobile phones, laptop computers, and tablet computers to large devices such as vehicles and aircraft. In particular, in recent years, active exploration has been carried out to use secondary batteries as a power source for vehicles.

[0003] Secondary batteries can be classified into lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, etc. according to electrode materials, etc. Various types of secondary batteries can be appropriately selected according to design capacity, use environment, etc. Compared with other types of secondary batteries, lithium-ion batteries can achieve relatively high voltage and capacity. Therefore, lithium-ion batteries are widely used in fields such as vehicle battery packs that require high-density energy storage devices.

[0004] The main configurations of secondary batteries such as lithium-ion batteries include a positive electrode material, a negative electrode material, a separator, an electrolyte, etc. The positive electrode material and the negative electrode material are arranged with a separator of an insulating material therebetween, and charging or discharging can be achieved by the movement of ions in the electrolyte.

[0005] On the other hand, if excessive heat or electrolyte decomposition occurs due to overcharging, foreign object insertion, damage to the insulating structure caused by external shock, etc., the internal pressure of the secondary battery may rise, resulting in the secondary battery catching fire or exploding. Therefore, some secondary batteries are provided with an exhaust port for discharging excessive internal pressure, etc. The exhaust port according to the prior art breaks under the action of the internal pressure, thereby helping to release internal heat, pressure, etc. However, in some cases, such an exhaust port may respond to an instantaneous pressure change or may be damaged by high-temperature by-products generated inside the secondary battery, resulting in a failure.

[0006] The above description is provided to help understand the technical background of the present disclosure and should not be construed as narrowing, limiting, or restricting the use of the technical idea of the present disclosure, etc. In addition, the content described or recited in the above description does not necessarily mean the prior art and may also include content that does not belong to the prior art. Summary of the Invention

[0007] (I) Technical Problems to be Solved

[0008] According to one aspect of the present disclosure, a secondary battery can be provided that can appropriately protect an exhaust port from the influence of an instantaneous pressure change or high-temperature by-products inside the housing.

[0009] However, the technical problems to be solved by the embodiments of the present disclosure are not necessarily limited to the above technical problems. Those skilled in the art can clearly understand other technical problems not mentioned from other records in the specification such as the specific implementation manners.

[0010] The secondary battery of the present disclosure can be widely applied to electric vehicles, battery charging stations, and other green technology fields such as solar power generation and wind power generation that utilize batteries. In addition, the secondary battery of the present disclosure can be used for eco-friendly electric vehicles, hybrid vehicles, etc. that prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0011] (II) Technical Solution

[0012] The secondary battery according to the present disclosure may include: a case that internally accommodates an electrode assembly; a cover plate that includes an exhaust port and seals an opening of the case; and a side insulator disposed below the cover plate. The side insulator may include: an exhaust port cover portion that includes a main chamber and is disposed below the exhaust port; and an assembly bracket on which the exhaust port cover portion is disposed.

[0013] According to one embodiment, the exhaust port cover portion may include a bottom surface that divides a lower side region of the main chamber. The bottom surface may be formed as a closed surface, and the pressure inside the case may be restricted from directly acting on the main chamber through the bottom surface.

[0014] According to one embodiment, the exhaust port cover portion may include a first side surface and a second side surface that divide a left side region and a right side region of the main chamber. The first side surface and the second side surface may respectively include a first inflow hole or a second inflow hole for transmitting the pressure inside the case to the main chamber.

[0015] According to one embodiment, the exhaust port cover portion may include a top surface that divides an upper side region of the main chamber. The top surface may include an exhaust hole formed through the top surface toward the exhaust port.

[0016] According to one embodiment, the exhaust port cover portion may include: a top surface that includes an exhaust hole formed through the top surface toward the exhaust port and divides an upper side region of the main chamber; and a sealing flange that protrudes from the top surface toward the cover plate by a predetermined height and extends along an edge of the top surface to include the exhaust hole of the exhaust port cover portion therein.

[0017] According to one embodiment, the exhaust port cover portion may include a first buffer chamber separated from the main chamber by a first internal partition.

[0018] According to one embodiment, the first buffer chamber may be partitioned into a space that is smaller than the main chamber by a predetermined degree.

[0019] According to one embodiment, the first buffer chamber may be connected to the interior of the housing through a first inflow hole formed on a first side surface of the exhaust port cover portion, and the first buffer chamber may be connected to the main chamber through a first buffer hole formed in the first internal partition.

[0020] According to one embodiment, the opening area of the first buffer hole may be smaller than the opening area of the first inflow hole by a predetermined degree.

[0021] According to one embodiment, the top surface of the first buffer chamber may be formed as a closed surface, and the top surface of the main chamber may include an exhaust hole formed through the top surface toward the exhaust port.

[0022] According to one embodiment, the first inflow hole may include a first baffle that extends from a side edge portion of the first inflow hole toward the main chamber by a predetermined length, and the first baffle may extend obliquely toward the center of the first inflow hole.

[0023] According to one embodiment, the exhaust port cover portion may include a second buffer chamber separated from the main chamber by a second internal partition, and the second buffer chamber is disposed corresponding to the first buffer chamber with the main chamber therebetween.

[0024] According to one embodiment, the side insulator may include: a first side insulator including a part of the exhaust port cover portion; and a second side insulator including the remaining part of the exhaust port cover portion.

[0025] According to one embodiment, the assembly bracket may extend in the longitudinal direction, and the exhaust port cover portion may be disposed at the center in the longitudinal direction of the assembly bracket.

[0026] According to one embodiment, the assembly bracket may include: a first bending portion including a first coupling portion, and the first bending portion is formed at one end in the longitudinal direction of the assembly bracket; a second bending portion including a second coupling portion, and the second bending portion is formed at an opposite side end corresponding to the one end; a first assembly rib extending a predetermined length along the longitudinal direction of the assembly bracket in a side region of the assembly bracket centered on the exhaust port cover portion to be coupled to the cover plate; and a second assembly rib extending a predetermined length along the longitudinal direction of the assembly bracket in a region opposite to the side region to be coupled to the cover plate.

[0027] (III) Advantageous Effects

[0028] A secondary battery according to an embodiment of the present disclosure may include a side insulator fastened to a cover plate. The side insulator may include an exhaust port cover portion provided at a lower portion of the exhaust port. According to an embodiment of the present disclosure, the exhaust port cover portion may serve to protect the exhaust port from instantaneous pressure changes, high-temperature by-products, etc.

[0029] In addition, the exhaust port cover portion may further include an inflow hole on a side surface and an exhaust hole provided toward the exhaust port. The exhaust port cover portion according to an embodiment of the present disclosure may rectify the pressure inside the housing, etc. and transfer it to the exhaust port. The main chamber provided in the exhaust port cover portion according to one embodiment may be used as a buffering means or a buffering space for buffering pressure changes. In some embodiments, a buffering chamber may be added to further enhance the above-described effects and functions.

[0030] However, the technical effects obtainable through the embodiments of the present disclosure are not necessarily limited to the above effects. Those of ordinary skill in the technical field to which the present disclosure pertains can clearly understand other technical effects not mentioned from other descriptions in the detailed description, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1a is a schematic external perspective view of a secondary battery according to one embodiment.

[0032] Figure 1b is Figure 1a a schematic exploded perspective view of the secondary battery shown.

[0033] Figure 1c is Figure 1a a schematic internal cross-sectional view of the secondary battery shown.

[0034] Figure 2a is a schematic perspective view of a side insulator according to one embodiment.

[0035] Figure 2b is along Figure 2aSchematic cross-sectional view of the side insulator taken along the line C1-C1'.

[0036] Figure 3a Is a schematic perspective view of the side insulator according to another embodiment.

[0037] Figure 3b Is along Figure 3a Schematic cross-sectional view of the side insulator taken along the line C2-C2'.

[0038] Figure 4a Is a schematic perspective view of the side insulator according to yet another embodiment.

[0039] Figure 4b Is along Figure 4a Schematic cross-sectional view of the side insulator taken along the line C3-C3'.

[0040] Explanation of reference numerals:

[0041] 100: Secondary battery

[0042] 110: Case

[0043] 120: Electrode assembly

[0044] 130: Cover plate

[0045] 200: Side insulator

[0046] 210: First side insulator

[0047] 220: Second side insulator

[0048] 230: Exhaust port cover part

[0049] 240: Assembly bracket Detailed implementation manners

[0050] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For convenience, in the following description, details of configurations that obscure the technical gist of the present disclosure or known configurations will be omitted.

[0051] The following embodiments are provided to more completely illustrate the present disclosure to those skilled in the art. The following embodiments are provided to help understand the present disclosure, and the technical idea of the present disclosure is not necessarily limited to the specific embodiments described below. It should be understood that the present disclosure widely includes various equivalents, alternatives, transformations, etc. that implement the technical idea described in the following embodiments.

[0052] The terms used in the following embodiments are provided to more completely illustrate a specific embodiment based on the above viewpoints. Therefore, the terms used in the following embodiments should not be construed as narrowing, limiting, or restricting the use of the technical idea of the present disclosure, etc.

[0053] In the following description, unless explicitly excluded from the context, singular expressions may be interpreted to include plural expressions. Additionally, in the following description, the expression "including" means that the configurations, components, operations, features, steps, numbers, etc. described exist, and does not mean excluding the addition of one or more other configurations, components, operations, features, steps, numbers, etc.

[0054] In the following description, terms such as "first" and "second" may be used to distinguish a specific component from other components. However, the purpose of using such terms is to distinguish a specific component from other components for clear illustration, and the technical concept of each component should not be interpreted as being limited by such terms.

[0055] The secondary battery described in this specification may include a battery capable of charging and discharging. For example, the secondary battery may include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, etc. In this specification, it is mainly assumed that the secondary battery is a lithium-ion battery for illustration. Generally, lithium-ion batteries may have advantages such as light weight, high energy density, and low self-discharge rate. However, it should be understood that the technical concepts described in this specification may also be applicable to other suitable types of batteries other than lithium-ion batteries.

[0056] The secondary battery described in this specification may include a single physical unit cell or a cluster unit combining multiple of the said unit cells. For example, according to the classification criteria commonly used in the current vehicle field, the secondary battery may include battery cells, battery modules, battery packs, etc. In this specification, it is mainly assumed that the secondary battery is a battery cell as a single unit for illustration. Generally, a battery cell is the basic constituent unit of a battery pack including a positive electrode material, a negative electrode material, a separator, an electrolyte, etc. However, it should be understood that according to needs, the technical concepts described in this specification may also be applicable to other suitable types of cluster units such as battery modules and battery packs.

[0057] The secondary battery described in this specification may include various packaging types. For example, according to the classification criteria commonly used in the relevant field currently, the secondary battery may be packaged into a cylindrical shape, a prismatic shape, a pouch shape, a coin shape, etc. In this specification, it is mainly assumed that the secondary battery is packaged into a prismatic shape for illustration. The prismatic packaging such as a prismatic battery usually has advantages in terms of durability, safety, ease of installation, etc. However, it should be understood that according to needs, the technical concepts described in this specification may also be applicable to other suitable packaging types such as cylindrical, pouch, and coin shapes.

[0058] The secondary battery described in this specification can be used in various devices that require electrical energy. For example, the secondary battery can be applied to the field of vehicles that use electrical energy as the main power source or auxiliary power source. As another example, the secondary battery can be applied to the field of aircraft such as personal aircraft, drones, and unmanned aerial vehicles, the field of electronic devices such as mobile phones, laptops, and tablet computers, and the field of power tools such as electric drills, electric grinders, and electric hammers. However, it should be understood that the secondary battery described in this specification can be widely applied to various devices that operate based on electrical energy other than those described above.

[0059] Figure 1a is a schematic perspective view of the exterior of a secondary battery according to one embodiment. Figure 1b is Figure 1a a schematic exploded perspective view of the secondary battery shown. Figure 1c is Figure 1a a schematic internal cross-sectional view of the secondary battery shown, which is a cross-sectional view taken along the Figure 1a 1c-1c' line of

[0060] For ease of explanation, in this embodiment, a single battery cell encapsulated in a prismatic shape is illustrated.

[0061] Referring to Figures 1a to 1c , the secondary battery 100 according to this embodiment can include a housing 110.

[0062] The housing 110 can provide an internal space capable of accommodating the electrode assembly 120 and the like. In this embodiment, the housing 110 is illustrated as having a substantially cubic shape.

[0063] The housing 110 can include an opening 111 connected to the internal space. In this embodiment, the opening 111 is shown to be provided at the upper end of the housing 110. However, the position of the opening 111 can be changed as needed and is not necessarily limited to the example shown. The opening 111 can be used as a passage for inserting the electrode assembly 120 and the like. Additionally, the opening 111 can be used as a connection space for the electrical connection between the electrode assembly 120 and the electrode terminals. The opening 111 can be closed by a cover plate 130.

[0064] The material of the housing 110 can be appropriately selected considering thermal conductivity, electrical conductivity, rigidity corresponding to the swelling of the electrode assembly 120, processability, manufacturing cost, etc. As an example, the housing 110 can be made of a metal material including aluminum or aluminum alloy, etc.

[0065] On the other hand, the secondary battery 100 according to this embodiment can include an electrode assembly 120.

[0066] The electrode assembly 120 may be disposed in the inner space of the housing 110. As needed, the electrode assembly 120 may be accommodated in the insulating bag 124 and disposed inside the housing 110.

[0067] The electrode assembly 120 may include a positive electrode material 121. The positive electrode material 121 may include a positive electrode current collector and a positive electrode active material. In some embodiments, the positive electrode current collector may include aluminum, aluminum alloy, etc., and the positive electrode active material may include lithium cobaltate, lithium manganate, lithium nickelate, lithium iron phosphate, etc. The positive electrode active material may be coated on the surface of the positive electrode current collector. A part of the positive electrode current collector without the coated positive electrode active material may be used as the positive electrode terminal 121a. In some embodiments, a plurality of positive electrode terminals 121a may be provided, and some or all of the plurality of positive electrode terminals 121a may be joined to each other.

[0068] The electrode assembly 120 may include a negative electrode material 122. The negative electrode material 122 may include a negative electrode current collector and a negative electrode active material. In some embodiments, the negative electrode current collector may include copper, copper alloy, nickel, nickel alloy, etc., and the negative electrode active material may include carbon, silicon, etc. The negative electrode active material may be coated on the surface of the negative electrode current collector. A part of the negative electrode current collector without the coated negative electrode active material may be used as the negative electrode terminal 122a. In some embodiments, a plurality of negative electrode terminals 122a may be provided, and some or all of the plurality of negative electrode terminals 122a may be joined to each other.

[0069] The electrode assembly 120 may include a separator 123. The separator 123 may be disposed between the positive electrode material 121 and the negative electrode material 122. The separator 123 may function to limit the physical contact between the positive electrode material 121 and the negative electrode material 122 and provide a channel for ion movement. In some embodiments, the separator 123 may be made of a polymer material including polyethylene, polypropylene, etc. Additionally, the separator 123 may include a dry separator and a wet separator. In some embodiments, the separator 123 may include a coating, and the coating includes a ceramic coating, etc.

[0070] The electrode assembly 120 may be formed by arranging the above components in a winding, stacking, etc. manner. As an example, the electrode assembly 120 may be formed in a structure where the positive electrode material 121, the negative electrode material 122, and the separator 123 are wound around a longitudinal axis or a transverse axis. Alternatively, the electrode assembly 120 may be formed in a structure where the above winding structure is compressed in a direction substantially perpendicular to the winding axis. The winding structure may be referred to as a "jellyroll" etc. in the art.

[0071] As another example, the electrode assembly 120 may be formed in a structure in which a positive electrode material 121, a negative electrode material 122, and a separator 123 are stacked. In some cases, in the stacked structure, the separator 123 may be formed in a structure in which a plurality of unit separators 123 that are continuous in the length direction are sequentially folded and stacked according to the stacking of the positive electrode material 121 and the negative electrode material 122. The stacked structure may be referred to as "stack and folding", "z-folding", etc. in the art. However, in this embodiment, the arrangement of each component of the electrode assembly 120 is not particularly limited. The electrode assembly 120 may have various arrangements other than the above examples.

[0072] In some embodiments, the electrode assembly 120 may be a combination of a plurality of unit cells. As an example, the electrode assembly 120 may include unit cells wound in a jelly roll manner, and two or more unit cells may be combined to constitute the electrode assembly 120. In this embodiment, the electrode assembly 120 is a combination of two jelly roll units. As another example, the electrode assembly 120 may include unit cells wound in a stacked and folded manner, and two or more unit cells may be combined to constitute the electrode assembly 120.

[0073] The electrode assembly 120 may be accommodated in the internal space of the housing 110 together with the electrolyte. In some embodiments, the electrolyte may be formed of an organic solvent containing a lithium salt. As an example, the lithium salt may include liquid or gel-like lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), etc., and the organic solvent may include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and linear carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC).

[0074] In some other embodiments, the electrolyte may be omitted or replaced. As an example, when an inorganic solid electrolyte is used, the liquid or gel-like electrolyte may be omitted.

[0075] On the other hand, the secondary battery 100 according to this embodiment may include a cover plate 130.

[0076] The cover plate 130 may close the opening 111. In this embodiment, the cover plate 130 is shown as having a quadrilateral plate shape corresponding to the opening 111. The cover plate 130 may be coupled to the housing 110 to seal the internal space of the housing 110 in which the electrode assembly 120 is disposed. In some embodiments, the cover plate 130 may be welded and joined to the housing 110 by ultrasonic welding, laser welding, etc.

[0077] The positive terminal 131 and the negative terminal 132 may be provided on the cover plate 130. The positive terminal 131 may be electrically connected to the positive electrode connector 121a of the electrode assembly 120, and the negative terminal 132 may be electrically connected to the negative electrode connector 122a of the electrode assembly 120.

[0078] The cover plate 130 may include an electrolyte injection port 134. The electrolyte injection port 134 may be used to inject electrolyte into the internal space of the housing 110. In the present embodiment, the electrolyte injection port 134 is disposed adjacent to the vent 133 in the central region of the cover plate 130. However, the position of the electrolyte injection port 134 may be variously changed as needed and is not necessarily limited to the illustrated example. The electrolyte injection port 134 may be appropriately sealed after electrolyte injection, formation process, etc. In some embodiments, the electrolyte injection port 134 may be sealed by pressing in a spherical sealing member made of a polymer resin.

[0079] The cover plate 130 may include a vent 133. In the present embodiment, the vent 133 is disposed between the positive terminal 131 and the negative terminal 132. However, the position of the vent 133 may be variously changed as needed and is not necessarily limited to the illustrated example. In some other embodiments, the vent 133 may be disposed in the housing 110 or added to the housing 110. The vent 133 may be opened under the action of the internal pressure of the housing 110. The vent 133 may serve to discharge the internal pressure to the outside of the housing 110, thereby contributing to stabilizing the internal components of the housing 110.

[0080] On the other hand, the secondary battery 100 according to the present embodiment may include a side insulator 140

[0081] In the present embodiment, the side insulator 140 may be disposed on the lower side portion of the cover plate 130. The side insulator 140 may serve to ensure an appropriate spacing between the cover plate 130 and the electrode assembly 120 and to ensure an additional insulating structure at the connection portions of the electrode connectors 121a and 122a. In addition, the side insulator 140 may also be used as a protection means for the vent 133. The detailed function of the side insulator 140 will be described in detail later.

[0082] In the present embodiment, the side insulator 140 may be divided into a pair. Each of the divided side insulators 140 may be coupled to each other with the cover plate 130 interposed therebetween. Thus, the lower side portion of the cover plate 130 may be covered by the side insulator 140. On the other hand, the side insulator 140 may be mounted to be coupled to the upper end of the insulating bag 124 and inserted into the housing 110.

[0083] Figure 2a is a schematic perspective view of a side insulator according to an embodiment. Figure 2b is along Figure 2aSchematic cross-sectional view of the side insulator taken along line C1-C1'.

[0084] For convenience, hereinafter, new reference numerals will be given to the side insulators according to the respective embodiments and described.

[0085] Refer to Figure 2a and Figure 2b In this embodiment, the side insulator 200 can be divided into a pair. That is, the side insulator 200 of this embodiment can be divided into a first side insulator 210 and a second side insulator 220. The first side insulator 210 and the second side insulator 220 formed by division can bring convenience in terms of assembly.

[0086] However, the side insulator 200 of the present disclosure is not necessarily limited to the above-described divided form. As needed, the side insulator 200 can be integrally formed as one or can be divided into three or more. In addition, the side insulator 200 can be divided into a plurality in a divided form other than the shown form. For example, the side insulator 200 can be divided in a divided form that is asymmetric with each other. For reference, one of the cases where the first side insulator 410 and the second side insulator 420 are divided and formed in different forms is shown in Figure 4a etc. later.

[0087] In this embodiment, the first side insulator 210 and the second side insulator 220 are the same or similar to each other. Therefore, for convenience, hereinafter, the first side insulator 210 will be mainly described.

[0088] On the other hand, the side insulator 200 of this embodiment can include an exhaust port cover portion 230.

[0089] The exhaust port cover portion 230 can be provided below the exhaust port 133. That is, the position of the exhaust port cover portion 230 can be set such that when the side insulator 200 is fastened to the cover plate 130, the exhaust port cover portion 230 covers the lower part of the exhaust port 133. In this embodiment, the exhaust port 133 is shown to be approximately provided at the left and right centers of the cover plate 130, and the exhaust port cover portion 230 is shown to be provided at the left and right centers of the side insulator 200 to correspond to the exhaust port 133.

[0090] Focusing on the description of the first side insulator 210, the exhaust port cover portion 230 can be provided with a main chamber 231. In this embodiment, a part of the main chamber 231 can be formed in the first side insulator 210, and the remaining part can be formed in the second side insulator 220. The main chamber 231 can be separated from the outside by combining the first side insulator 210 and the second side insulator 220.

[0091] The exhaust port cover portion 230 may include a bottom surface 231a that divides the lower region of the main chamber 231. In the present embodiment, the bottom surface 231a of the exhaust port cover portion 230 may be formed as a closed surface. The closed bottom surface 231a may serve to prevent the pressure or by-products inside the housing 110 from directly flowing into the main chamber 231. That is, the closed bottom surface 231a may serve to protect the exhaust port 133 from instantaneous pressure changes, high-temperature by-products, etc. For reference, in the present embodiment, the pressure, etc. inside the housing 110 may act on the exhaust port 133 through the first side surface 231b and the second side surface 231c, which will be described later.

[0092] On the other hand, the exhaust port cover portion 230 may include a first side surface 231b and a second side surface 231c that divide the left and right regions of the main chamber 231. A first inflow hole 232a may be formed in the first side surface 231b, and a second inflow hole 232b may be formed in the second side surface 231c. The first inflow hole 232a and the second inflow hole 232b may be formed through the first side surface 231b and the second side surface 231c, respectively, to provide a flow path for entering and exiting the main chamber 231 inside and outside through the first side surface 231b and the second side surface 231c. In the present embodiment, the first inflow hole 232a has a slit shape extending vertically and is formed through the first side surface 231b, and a plurality of first inflow holes 232a are spaced apart along the first side surface 231b. Similarly, the second inflow hole 232b has a slit shape extending vertically and is formed through the second side surface 231c, and a plurality of second inflow holes 232b are spaced apart along the second side surface 231c. However, the shape, number, etc. of the first inflow hole 232a and the second inflow hole 232b may be changed as needed and are not necessarily limited to the illustrated examples.

[0093] On the other hand, the exhaust port cover portion 230 may include a top surface 231d that divides the upper region of the main chamber 231. In the present embodiment, the main chamber 231 is shown as a space having a substantially rectangular parallelepiped shape formed by the bottom surface 231a, the first side surface 231b, the second side surface 231c, the top surface 231d, etc. An exhaust hole 233 may be formed in the top surface 231d. The exhaust hole 233 is formed through the top surface 231d to provide a flow path for entering and exiting the main chamber 231 inside and outside through the top surface 231d. In the present embodiment, the exhaust hole 233 may have a slit shape extending back and forth and is formed through the top surface 231d, and a plurality of exhaust holes 233 may be spaced apart along the top surface 231d. However, the shape, number, etc. of the exhaust hole 233 may be changed as needed and are not necessarily limited to the illustrated examples.

[0094] As needed, a sealing flange 234 may be provided at the edge of the top surface 231d of the exhaust port cover portion 230. The sealing flange 234 may protrude a predetermined height from the edge portion of the top surface 231d toward the cover plate 130. Additionally, the sealing flange 234 may be formed to extend along the edge of the top surface 231d. In this embodiment, a part of the sealing flange 234 is formed in the exhaust port cover portion 230 formed in the first side insulator 210, and the remaining part is formed in the exhaust port cover portion 230' formed in the second side insulator 220. The sealing flange 234 may be formed to extend in a closed graphic form that includes the area of the top surface 231d of the exhaust port cover portion 230 or the exhaust hole 233 inside thereof. In this embodiment, the sealing flange 234 may be formed to extend in a closed quadrilateral form in which a part formed in the first side insulator 210 and the remaining part formed in the second side insulator 220 are combined to include the area of the top surface 231d of the exhaust port cover portion 230 inside thereof.

[0095] The sealing flange 234 may separate the flow path between the exhaust hole 233 and the exhaust port 133 from the outside. Thus, the pressure acting on the exhaust hole 233 and the like can be appropriately transmitted to the exhaust port 133. However, in this embodiment, the sealing flange 234 does not need to form a complete seal with the outside. As long as the sealing flange 234 provides a path through which the pressure of the main chamber 231 and the like can be appropriately transmitted to the exhaust port 133.

[0096] On the other hand, the side insulator 200 of this embodiment may include an assembly bracket 240.

[0097] In this embodiment, the assembly brackets 240 may be provided on the first side insulator 210 and the second side insulator 220 respectively. Focusing on the first side insulator 210, the assembly bracket 240 may extend left and right to form a predetermined length, and the exhaust port cover portion 230 may be disposed substantially at the center of the assembly bracket 240. The assembly bracket 240 extends left and right, and the length of the assembly bracket 240 may correspond substantially to the cover plate 130. In this embodiment, the assembly bracket 240 is shown in the shape of a bar or beam having a predetermined width up and down. However, the specific shape of the assembly bracket 240 may be changed as needed and is not necessarily limited to the shown example.

[0098] A first bending portion 241 may be formed at one end of the assembly bracket 240 in the longitudinal direction. The first bending portion 241 may be formed by bending one end region of the assembly bracket 240 toward the second side insulator 220. A first engaging portion 241a may be provided at the end of the first bending portion 241. The first engaging portion 241a engages with the corresponding first engaging portion 241a' of the second side insulator 220, so that the first side insulator 210 and the second side insulator 220 can be engaged. In this embodiment, the first engaging portion 241a of the first side insulator 210 is shown as an engaging hole of a predetermined shape, and the corresponding first engaging portion 241a' of the second side insulator 220 is shown as an engaging protrusion corresponding to the engaging hole. However, the exemplary engaging forms, manners, etc. may be changed as needed and are not necessarily limited to the shown examples.

[0099] On the other hand, a second bending portion 242 may be formed at the opposite end of the first bending portion 241. The second bending portion 242 may be formed by bending the opposite end region of the assembly bracket 240 toward the second side insulator 220. A second engaging portion 242a may be provided at the end of the second bending portion 242. The second engaging portion 242a engages with the corresponding second engaging portion 242a' of the second side insulator 220, so that the first side insulator 210 and the second side insulator 220 can be engaged. In this embodiment, the second engaging portion 242a is shown as having an engaging structure similar to that of the first engaging portion 241a. However, the exemplary engaging forms, manners, etc. may be changed as needed and are not necessarily limited to the shown examples.

[0100] On the other hand, a first assembly rib 243 and a second assembly rib 244 may be formed at the top end of the assembly bracket 240. The first assembly rib 243 may extend a predetermined length in the longitudinal direction of the assembly bracket 240 in one side region of the assembly bracket 240 centered on the exhaust port cover portion 230. In addition, the second assembly rib 244 may extend a predetermined length in the longitudinal direction of the assembly bracket 240 in the opposite side region corresponding to the one side region. The first assembly rib 243 and the second assembly rib 244 may be used to engage the side insulator 200 and the cover plate 130 and enhance the rigidity of the assembly bracket 240 extending in the longitudinal direction.

[0101] On the other hand, in this embodiment, the second side insulator 220 may be the same as or similar to the first side insulator 210 described above. The second side insulator 220 may have a shape symmetrical to that of the first side insulator 210, and the second side insulator 220 may be engaged with the first side insulator 210 to form a side insulator 200 that covers the lower side portion of the cover plate 130.

[0102] On the other hand, the side insulator 200 as described above may be partially or entirely made of an insulating material. Additionally, as needed, the side insulator 200 may be partially or entirely made of an elastic material. The elastic material helps to improve the sealing performance inside the housing 110. For example, the side insulator 200 may be partially or entirely made of nitrile rubber (NBR), fluororubber (FKM), ethylene propylene diene monomer rubber (EPDM), chloroprene rubber (CR), etc.

[0103] Referring to Figure 2b , the side insulator 200 of this embodiment may be coupled to the cover plate 130 such that the exhaust port cover portion 230 is disposed on the lower side of the exhaust port 133. The exhaust port 133 may be disposed in the inner region of the sealing flange 234 on a plane. In this state, the side insulator 200 may function to protect the exhaust port 133 from the influence of instantaneous pressure changes or high-temperature by-products inside the housing 110. That is, the pressure P1 acting on the bottom surface 231a of the exhaust port cover portion 230 is appropriately restricted by the closed bottom surface 231a and does not directly act on the main chamber 231, thereby protecting the exhaust port 133 from the influence of instantaneous pressure changes. Additionally, the elastic deformation of the bottom surface 231a and the internal space of the main chamber 231 may be used as a buffering means or buffer space for buffering the instantaneous pressure changes as described above.

[0104] On the other hand, the pressure P2 inside the housing 110 may act on the main chamber 231 through the first side surface 231b and the second side surface 231c. Specifically, the pressure P2 inside the housing 110 may act on the main chamber 231 through the first inflow hole 232a formed in the first side surface 231b and the second inflow hole 232b formed in the second side surface 231c, and the pressure P2 acting on the main chamber 231 may act on the upper exhaust port 133 through the exhaust hole 233 formed in the top surface 231d of the main chamber 231. The exhaust port 133 may be appropriately broken at a predetermined pressure by the action of the rectified pressure as described above.

[0105] In some cases, the main chamber 231 may be used as a means to prevent the inflow of pressure, by-products, etc. flowing back from the exhaust port 133 into the inside of the housing 110. That is, if the exhaust port 133 is accidentally broken by high-temperature by-products flowing back from an adjacent another battery cell, the pressure, by-products, etc. flowing back from the broken exhaust port 133 are first accommodated in the main chamber 231, thereby partially restricting the inflow of pressure, by-products, etc. into the inside of the housing 110. The closed bottom surface 231a of the exhaust port cover portion 230 may restrict the direct inflow of the pressure, by-products, etc. into the electrode assembly 120 as described above. Additionally, the pressure, by-products, etc. accommodated in the main chamber 231 may be discharged limitedly through the first inflow hole 232a and the second inflow hole 232b. For reference, in Figure 3aIn the above, buffer chambers 335 and 336 can be added to further limit the backflow of pressure, by-products, etc.

[0106] The side insulator 200 as described above can appropriately limit the direct action of instantaneous pressure changes, etc. on the exhaust port 133 through the bottom surface 231a of the exhaust port cover portion 230. In addition, the exhaust port cover portion 230 can transfer the pressure flowing into the first side surface 231b portion and the second side surface 231c portion to the exhaust port 133 through the main chamber 231. Here, the main chamber 231 serves as a buffering means or buffering space to more accurately transfer the pressure to the exhaust port 133.

[0107] Figure 3a It is a schematic perspective view of a side insulator according to another embodiment. Figure 3b is along Figure 3a The schematic cross-sectional view of the side insulator taken along the C2 - C2' line shown.

[0108] For convenience, the following embodiments will focus on explaining the differences from the above embodiments.

[0109] Referring to Figure 3a and Figure 3b The side insulator 300 of this embodiment can be divided into a first side insulator 310 and a second side insulator 320. The first side insulator 310 and the second side insulator 320 can have symmetrical shapes and can be the same or similar to each other. This is roughly similar to the above embodiment.

[0110] On the other hand, the side insulator 300 of this embodiment can include an exhaust port cover portion 330.

[0111] The exhaust port cover portion 330 can be provided below the exhaust port 133. Similar to the above embodiment, the pressure inside the housing 110, etc. can be transferred to the exhaust port 133 through the exhaust port cover portion 330.

[0112] The exhaust port cover portion 330 can include a bottom surface 331a, a first side surface 331b, a second side surface 331c, and a top surface 331d. The bottom surface 331a, the first side surface 331b, the second side surface 331c, and the top surface 331d can partition a predetermined space from the outside. The bottom surface 331a can be formed as a closed surface, which can serve to protect the exhaust port 133 from the influence of instantaneous pressure changes or high-temperature by-products, etc. inside the housing 110. A first inflow hole 332a can be formed in the first side surface 331b, and a second inflow hole 332b can be formed in the second side surface 331c. In addition, an exhaust hole 333 can be formed in the top surface 331d. The pressure inside the housing 110, etc. can be transferred to the exhaust port 133 through the first inflow hole 332a, the second inflow hole 332b, and the exhaust hole 333. This is roughly similar to the above embodiment.

[0113] On the other hand, the exhaust port cover portion 330 of the present embodiment may include a main chamber 331 and buffer chambers 335, 336.

[0114] The exhaust port cover portion 330 of the present embodiment is different from that of the above embodiment in that buffer chambers 335, 336 are added. The buffer chambers 335, 336 can be formed by partially partitioning the internal space of the exhaust port cover portion 330 from the main chamber 331. In the present embodiment, the buffer chambers 335, 336 can be generally partitioned into spaces smaller than the main chamber 331.

[0115] A plurality of buffer chambers 335, 336 can be provided as needed. In the present embodiment, the buffer chambers 335, 336 are provided in pairs on the left and right sides of the main chamber 331. For convenience, the following buffer chambers 335, 336 are respectively referred to as the first buffer chamber 335 and the second buffer chamber 336. Therefore, the first buffer chamber 335 and the second buffer chamber 336 can be separated on the left and right sides of the main chamber 331 with the main chamber 331 therebetween.

[0116] The first buffer chamber 335 can be provided on one side (the left side in the figure) of the main chamber 331 and can be separated from the main chamber 331 by a first internal partition 335a. A first buffer hole 335b connecting the first buffer chamber 335 and the main chamber 331 can be formed in the first internal partition 335a. As described above, a first inflow hole 332a connecting the inside of the housing 110 and the first buffer chamber 335 is formed on the first side surface 331b opposite to the first internal partition 335a.

[0117] The first buffer chamber 335 can be connected to the main chamber 331 through the first buffer hole 335b. In the area partitioned into the first buffer chamber 335, the exhaust hole 333 on the top surface 331d can be appropriately omitted, that is, different from the main chamber 331 to be described later, the top surface 331d' of the first buffer chamber 335 can be formed as a closed surface. Therefore, the pressure inside the housing 110 and the like can be transmitted to the first buffer chamber 335 through the first inflow hole 332a and then to the main chamber 331 through the first buffer hole 335b.

[0118] The first buffer chamber 335 can be partitioned into a space smaller than the main chamber 331. As an example, the first buffer chamber 335 can be partitioned into a space whose volume is 10 - 30% of the volume of the main chamber 331.

[0119] In addition, the first buffer hole 335b may be smaller than the first inflow hole 332a. That is, the total opening area of the first buffer hole 335b may be smaller than the total opening area of the first inflow hole 332a by a predetermined degree. In this embodiment, the width of the first buffer hole 335b is shown to correspond to that of the first inflow hole 332a, but the height of the first buffer hole 335b is smaller than that of the first inflow hole 332a by a predetermined degree.

[0120] The first buffer chamber 335 can play a role of accommodating part of the instantaneous pressure change and transmitting the rectified pressure to the main chamber 331 through the area difference between the first buffer hole 335b and the first inflow hole 332a as described above. In addition, the area difference between the first buffer hole 335b and the first inflow hole 332a can play a role of restricting the backflow of pressure, by-products, etc. from the main chamber 331 to the inside of the housing 110.

[0121] On the other hand, the second buffer chamber 336 can be disposed on the opposite side (the right side in the figure) of the first buffer chamber 335 across the main chamber 331. The second buffer chamber 336 is substantially similar to the first buffer chamber 335 described above. That is, the second buffer chamber 336 can be separated from the main chamber 331 by the second internal partition 336a, and a second buffer hole 336b can be formed in the second internal partition 336a. In addition, the top surface 331d" of the second buffer chamber 336 can be formed as a closed surface, and the second buffer hole 336b can be smaller than the second inflow hole 332b.

[0122] In the exhaust port cover portion 330 of this embodiment, the first buffer chamber 335 and the second buffer chamber 336 are added as described above, so that the pressure inside the housing 110, etc. can be transmitted to the main chamber 331 through the first buffer chamber 335 and the second buffer chamber 336. The first buffer chamber 335 and the second buffer chamber 336 are provided with the first buffer hole 335b and the second buffer hole 336b which are smaller than the first inflow hole 332a and the second inflow hole 332b by a predetermined degree, and can rectify the pressure, etc. acting on the first inflow hole 332a and the second inflow hole 332b by a predetermined degree and transmit it to the main chamber 331. In addition, the first buffer chamber 335 and the second buffer chamber 336 can play a role of partially restricting the backflow of pressure, by-products, etc. when the exhaust port 133 is accidentally broken.

[0123] On the other hand, the side insulator 300 of this embodiment may include an assembly bracket 340.

[0124] The mounting bracket 340 can be respectively disposed on the first side insulator 310 and the second side insulator 320, and can extend left and right with the central exhaust port cover portion 330 as the center to form a predetermined length. At each end of the mounting bracket 340, a first engaging portion 341a and a second engaging portion 342a can be respectively formed to engage with the corresponding second side insulator 320. In this embodiment, the mounting bracket 340 is substantially similar to the above-described embodiment.

[0125] Figure 4a is a schematic perspective view of a side insulator according to another embodiment. Figure 4b is along Figure 4a The schematic cross-sectional view of the side insulator taken along the line C3 - C3' shown.

[0126] Refer to Figure 4a and Figure 4b In this embodiment, the side insulator 400 can be divided into a first side insulator 410 and a second side insulator 420. Compared with the above-described embodiment, the side insulator 400 in this embodiment can be divided into a first side insulator 410 and a second side insulator 420, and the first side insulator 410 and the second side insulator 420 have partially different configurations. In this embodiment, most components can be disposed on the first side insulator 410, while the second side insulator 420 can only partially function as a mounting bracket.

[0127] On the other hand, the first side insulator 410 of this embodiment can include an exhaust port cover portion 430.

[0128] The exhaust port cover portion 430 can be disposed below the exhaust port 133, which can limit the direct transfer of the pressure inside the housing 110, etc. to the exhaust port 133. Compared with the above-described embodiment, the exhaust port cover portion 430 in this embodiment is basically disposed on the first side insulator 410, while the second side insulator 420 can only partially function as a mounting bracket.

[0129] The exhaust port cover portion 430 can include a bottom surface 431a, a first side surface 431b, a second side surface 431c, and a top surface 431d. The bottom surface 431a can be formed as a closed surface, which can function to protect the exhaust port 133 from the influence of instantaneous pressure changes or high-temperature by-products inside the housing 110, etc. In addition, a first inflow hole 432a and a second inflow hole 432b can be respectively formed on the first side surface 431b and the second side surface 431c, and an exhaust hole 433 can be formed on the top surface 431d. The pressure inside the housing 110, etc. can be transferred to the exhaust port 133 through the first inflow hole 432a, the second inflow hole 432b, and the exhaust hole 433.

[0130] In addition, the exhaust port cover portion 430 may include a main chamber 431 and buffer chambers 435, 436. Similar to the above-described embodiments, the buffer chambers 435, 436 may include a first buffer chamber 435 and a second buffer chamber 436, and the first buffer chamber 435 and the second buffer chamber 436 may be separated from the main chamber 431 by a first internal partition 435a and a second internal partition 436a, respectively. Additionally, a first buffer hole 435b and a second buffer hole 436b may be formed in the first buffer chamber 435 and the second buffer chamber 436, respectively, and the first buffer hole 435b and the second buffer hole 436b may be smaller than the first inflow hole 432a and the second inflow hole 432b by a predetermined degree. In the present embodiment, the heights of the first buffer hole 435b and the second buffer hole 436b are shown to correspond to those of the first inflow hole 432a and the second inflow hole 432b, but the widths of the first buffer hole 435b and the second buffer hole 436b are smaller than those of the first inflow hole 432a and the second inflow hole 432b by a predetermined degree.

[0131] On the other hand, in the present embodiment, a first baffle 437a may be formed around the first inflow hole 432a and the second inflow hole 432b. The first baffle 437a may extend from the edge portions of the first inflow hole 432a and the second inflow hole 432b toward the inside of the main chamber 431 by a predetermined length. Additionally, the first baffle 437a may extend obliquely toward the centers of the first inflow hole 432a and the second inflow hole 432b by a predetermined degree. In the present embodiment, a pair of first baffles 437a extend obliquely from the edge portions of the first inflow hole 432a and the second inflow hole 432b.

[0132] Similar to the above, a second baffle 437b may be formed around the first buffer hole 435b and the second buffer hole 436b. The second baffle 437b may extend from the edge portions of the first buffer hole 435b and the second buffer hole 436b toward the inside of the main chamber 431 by a predetermined length, and may extend obliquely toward the centers of the first buffer hole 435b and the second buffer hole 436b by a predetermined degree. In the present embodiment, a pair of second baffles 437b extend obliquely from the edge portions of the first buffer hole 435b and the second buffer hole 436b.

[0133] The first baffle 437a and the second baffle 437b as described above assist in smoothly transmitting the pressure inside the housing 110, etc. to the first buffer chamber 435, the second buffer chamber 436, and the main chamber 431. Additionally, the first baffle 437a and the second baffle 437b can more effectively restrict the pressure, by-products, etc. flowing back from the main chamber 431 to the inside of the housing 110 in the event of an accidental breakage of the exhaust port 133.

[0134] On the other hand, although the present embodiment shows a case where the above-mentioned first baffle 437a and second baffle 437b are provided on both the first inflow hole 432a and the second inflow hole 432b, and the first buffer hole 435b and the second buffer hole 436b, the first baffle 437a and the second baffle 437b may be provided only on a part of the first inflow hole 432a and the second inflow hole 432b, and the first buffer hole 435b and the second buffer hole 436b as required. For example, in some embodiments, the first baffle 437a may be omitted, and only the second baffle 437b may be provided on the first buffer hole 435b and the second buffer hole 436b. As another example, the first baffle 437a may be selectively provided only on a part of the first inflow holes 432a among the plurality of first inflow holes 432a and a part of the second inflow holes 432b, or the second baffle 437b may be selectively provided only on a part of the first buffer holes 435b among the plurality of first buffer holes 435b and a part of the second buffer holes 436b.

[0135] On the other hand, the side insulator 400 of the present embodiment may include an assembly bracket 440.

[0136] The assembly brackets 440 may be respectively provided on the first side insulator 410 and the second side insulator 420, and may extend left and right around the central exhaust port cover portion 430 to form a predetermined length. In the present embodiment, the first bending portion 441 and the second bending portion 442 of the assembly bracket 440 provided on the first side insulator 410 are relatively long so as to correspond to the exhaust port cover portion 430 provided on the first side insulator 410.

[0137] As described above, the secondary battery according to an embodiment of the present disclosure may include a side insulator provided below the cover plate. The side insulator may include an exhaust port cover portion provided below the exhaust port, and the exhaust port cover portion may serve to protect the exhaust port from instantaneous pressure changes or high-temperature by-products. In addition, the exhaust port cover portion may include an inflow hole on the side and an exhaust hole facing the exhaust port, and may rectify and transfer the pressure inside the case to the exhaust port. The main chamber provided in the exhaust port cover portion may be used as a buffering means or a buffering space for buffering instantaneous pressure changes. In some embodiments, a buffering chamber may be added to further enhance the above functions and effects.

[0138] The embodiments of the present disclosure have been described above. However, those skilled in the art can make various modifications or changes to the present disclosure by adding, changing, deleting, or adding components without departing from the technical idea of the present disclosure described in the claims, and these modifications or changes will also be included in the scope of the claims of the present disclosure.

Claims

1. A secondary battery comprising: A shell body, accommodating an electrode assembly therein; a cover plate, comprising an exhaust port, and the cover plate seals the opening of the housing; as well as A side insulator is provided at the lower part of the cover plate, The side insulator comprises: An exhaust port cover portion includes a main chamber, and the exhaust port cover portion is disposed at a lower portion of the exhaust port; as well as An assembly bracket is provided on which the exhaust port cover is arranged.

2. The secondary battery according to claim 1, wherein The exhaust port cover includes a bottom surface that separates the lower area of ​​the main chamber. The bottom surface is formed as a closed surface, and the pressure inside the shell is limited by the bottom surface from directly acting on the main chamber.

3. The secondary battery according to claim 1, wherein The exhaust port cover includes a first side surface and a second side surface that separate the left area and the right area of ​​the main chamber, The first side includes a first inflow hole for transmitting the pressure inside the housing to the main chamber, The second side includes a second inflow hole for transmitting the pressure inside the housing to the main chamber.

4. The secondary battery according to claim 3, wherein The exhaust port cover includes a top surface that separates the upper area of ​​the main chamber. The top surface includes an exhaust hole formed through the top surface toward the exhaust port.

5. The secondary battery according to claim 1, wherein The exhaust port cover comprises: a top surface, including an exhaust hole formed through the top surface toward the exhaust port, and the top surface partitions an upper area of ​​the main chamber; and A sealing flange protrudes from the top surface toward the cover plate to form a predetermined height, and the sealing flange extends along the edge of the top surface to include the exhaust hole of the exhaust port cover portion inside.

6. The secondary battery according to claim 1, wherein The exhaust port cover includes a first buffer chamber separated from the main chamber by a first inner partition.

7. The secondary battery according to claim 6, wherein The first buffer chamber is partitioned into a space that is smaller than the main chamber by a predetermined degree.

8. The secondary battery according to claim 6, wherein The first buffer chamber is connected to the interior of the housing through a first inflow hole formed on a first side surface of the exhaust port cover, and the first buffer chamber is connected to the main chamber through a first buffer hole formed on the first inner partition.

9. The secondary battery according to claim 8, wherein An opening area of ​​the first buffer hole is smaller than an opening area of ​​the first inflow hole by a predetermined degree.

10. The secondary battery according to claim 8, wherein The top surface of the first buffer chamber is formed as a closed surface, The top surface of the main chamber includes an exhaust hole formed through the top surface toward the exhaust port.

11. The secondary battery according to claim 8, wherein The first inflow hole includes a first baffle plate, and the first baffle plate extends from an edge portion of one side of the first inflow hole toward the main chamber to form a predetermined length. The first baffle is formed to extend obliquely toward the center of the first inflow hole.

12. The secondary battery according to claim 6, wherein The exhaust port cover includes a second buffer chamber partitioned from the main chamber by a second inner partition plate, and the second buffer chamber is provided corresponding to the first buffer chamber across the main chamber.

13. The secondary battery according to claim 1, wherein The side insulator comprises: A first side insulator including a portion of the exhaust port cover; and The second side insulator includes the remaining portion of the exhaust port cover.

14. The secondary battery according to claim 1, wherein The assembly bracket extends in a length direction, and the exhaust port cover is disposed at a center of the assembly bracket in the length direction.

15. The secondary battery according to claim 14, wherein The assembly bracket comprises: A first bent portion, including a first coupling portion, and the first bent portion is formed at one end of the assembly bracket in the length direction; a second bent portion including a second joint portion, and the second bent portion is formed at an opposite side end portion corresponding to the one end; A first assembly rib extending to a predetermined length along the length direction of the assembly bracket at a side area of ​​the assembly bracket centered on the exhaust port cover portion so as to be combined with the cover plate; and A second assembly rib extends along the length direction of the assembly bracket to form a predetermined length at a side region opposite to the one side region to be combined with the cover plate.

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