Secondary battery

Abstract

A secondary battery is disclosed. The secondary battery includes: a prismatic case; an electrode assembly accommodated inside the case together with the electrolyte; a cover assembly coupled to one end of the housing and having an exhaust port; and a discharge pipe inside the housing and having one end adjacent to the lower surface of the housing and the other end communicating with the exhaust port.

Description

[0001] This application claims the priority and benefit of Korean Patent Application No. 10-2024-0012063, filed with the Korean Intellectual Property Office on January 26, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] Aspects of embodiments of the present disclosure relate to a secondary battery. Background Art

[0003] A secondary battery generally includes an electrode assembly, a separator between stacked or wound positive and negative electrode plates, a case accommodating the electrode assembly and an electrolyte, and a cover assembly sealing the case.

[0004] A secondary battery overheats during overcharging or physical damage. Additionally, chemical reactions inside the secondary battery accelerate, and thus additional heat is generated during this process. Chemical substances of the secondary battery start to decompose due to the heat. For example, a lithium salt, which is typically used as an electrolyte material, may decompose at high temperatures to generate gas, which increases the pressure inside the battery. Additionally, when the temperature inside the secondary battery rises sharply due to the accelerated chemical reaction and decomposition reaction, thermal runaway occurs. If the pressure inside the secondary battery continues to increase and exceeds a reference level, the case will eventually rupture and fire will occur.

[0005] When the pressure exceeds a certain level, an exhaust port can automatically open to discharge internal gas, and through this process, the internal pressure of the battery returns to and remains at a safe level. However, even when the exhaust port opens and the gas is discharged, the possibility of rupture and fire is still high due to the residual electrolyte inside the case.

[0006] The above information disclosed in this background art section is for enhancing the understanding of the background art of the present disclosure, and thus it may include information that does not constitute the prior art. Summary of the Invention

[0007] Embodiments of the present disclosure provide a secondary battery having an exhaust port that prevents decomposition of an electrolyte, which is a precursor to thermal runaway, by allowing the electrolyte to be discharged before the gas inside the case is discharged, thereby preventing thermal runaway.

[0008] A secondary battery according to an embodiment of the present disclosure includes: a prismatic case; an electrode assembly accommodated inside the case together with an electrolyte; a cover assembly coupled to one end of the case and having an exhaust port; and a discharge pipe inside the case and having one end adjacent to the lower surface of the case and the other end communicating with the exhaust port.

[0009] When the pressure inside the housing exceeds the reference pressure, the exhaust port can be opened to discharge the electrolyte, and then the gas can be discharged from inside the housing.

[0010] The discharge pipe can have a hollow tube shape.

[0011] The discharge pipe can not interfere with the electrode assembly.

[0012] The discharge pipe can have a bent portion.

[0013] The discharge pipe can include: a connecting pipe connected to the exhaust port; and a plurality of branch pipes branching from the connecting pipe and extending toward the lower surface of the housing.

[0014] The cover assembly can include a plurality of exhaust ports, and a plurality of discharge pipes can be connected to corresponding ones of the plurality of exhaust ports.

[0015] The discharge pipe can be made of an insulating material that does not react with the electrolyte.

[0016] A secondary battery according to another embodiment of the present disclosure includes: a pouch-type housing having a recess and an exhaust port for discharging gas at one side; an electrode assembly accommodated inside the housing together with an electrolyte; and a discharge pipe inside the housing and having one end adjacent to the lower surface of the housing and the other end communicating with the exhaust port.

[0017] When the pressure inside the housing exceeds the reference pressure, the exhaust port can be opened to discharge the electrolyte, and then the gas can be discharged from inside the housing.

[0018] The discharge pipe can have a hollow tube shape.

[0019] The discharge pipe can not interfere with the electrode assembly.

[0020] The discharge pipe can have a bent portion.

[0021] The discharge pipe can include: a connecting pipe connected to the exhaust port; and a plurality of branch pipes branching from the connecting pipe and extending toward the lower surface of the recess.

[0022] The housing can include a plurality of exhaust ports, and a plurality of discharge pipes can be connected to corresponding ones of the plurality of exhaust ports.

[0023] The discharge pipe can be made of an insulating material that does not react with the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present disclosure.

[0025] Figure 2 is Figure 1 a perspective view of the cover assembly and the electrode assembly of the secondary battery shown in

[0026] Figure 3 is Figure 2 a partial cross-sectional view of the lid assembly and the electrode assembly shown in

[0027] Figure 4 schematically shows the Figure 1 front view of the discharge pipe in the secondary battery shown in

[0028] Figure 5 schematically shows the Figure 4 front view of the secondary battery shown in

[0029] Figure 6 schematic side view of the discharge pipe according to another embodiment.

[0030] Figure 7 schematic side view of the discharge pipe according to yet another embodiment.

[0031] Figure 8 schematic side view of the discharge pipe according to still another embodiment.

[0032] Figure 9 is Figure 8 the schematic front view of the discharge pipe shown in

[0033] Figure 10 schematic side view of the discharge pipe according to another embodiment.

[0034] Figure 11 is Figure 10 the schematic front view of the discharge pipe shown in DETAILED DESCRIPTION

[0035] Embodiments of the present disclosure are provided to more fully describe aspects and features of the present disclosure to those skilled in the art, and the following embodiments can be modified in various other forms. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will convey aspects and features of the present disclosure to those skilled in the art.

[0036] It will be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, directly connected to or directly coupled to the other element or layer, or there may be one or more intervening elements or intervening layers. When an element or layer is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or intervening layers. For example, when a first element is described as being "coupled" or "connected" to a second element, the first element can be directly coupled to or directly connected to the second element, or the first element can be indirectly coupled to or indirectly connected to the second element via one or more intervening elements.

[0037] In the figures, for clarity of illustration, the dimensions of various elements, layers, etc. may be exaggerated. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any combination and all combinations of one or more of the associated listed items. Further, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure". Expressions such as "at least one of" and "any one of" when following a list of elements modify the entire list of elements and not individual elements in the list. For example, the expression "at least one of a, b, and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. As used herein, the term "use" and variations thereof may be considered to be synonymous with the term "utilize" and variations thereof, respectively. As used herein, the terms "substantially", "about" and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent deviations of measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0038] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or portions, these elements, components, regions, layers and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or portion from another element, component, region, layer or portion. Thus, a first element, component, region, layer or portion discussed below may be referred to as a second element, component, region, layer or portion without departing from the teachings of the exemplary embodiments.

[0039] For ease of description, spatially relative terms such as "under", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or feature to another (or others) element or feature as shown in the figures. It will be understood that the spatially relative terms are intended to cover different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "under" or "below" other elements or features will then be oriented "above" or "over" the other elements or features. Thus, the term "under" can cover both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0040] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "a" and "an" are also intended to include the plural forms. It will also be understood that when the terms "comprises", "comprising", and / or their variants are used in this specification, it is meant that the stated features, integers, steps, operations, elements, and / or components are present, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0041] Hereinafter, a secondary battery according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present disclosure. Figure 2 is Figure 1 a perspective view of a lid assembly and an electrode assembly of the secondary battery shown in Figure 3 is Figure 2 a partial cross-sectional view of the lid assembly and the electrode assembly shown in Figure 1 For convenience, the following description will be provided with the understanding that based on the

[0043] Referring to Figures 1 to 3 , a secondary battery 10 according to an embodiment of the present disclosure may include an electrode assembly 100, a housing 200 that houses the electrode assembly 100, and a lid assembly 300 coupled to the housing 200. For example, the secondary battery 10 may be a prismatic battery in which the housing 200 has a rectangular parallelepiped shape. However, this is merely an example, and aspects and features of the present disclosure may be applied to various types of secondary batteries, such as cylindrical secondary batteries and pouch-type secondary batteries.

[0044] Referring to Figure 2 and Figure 3, the electrode assembly 100 may be formed (or provided) by winding a unit stack body composed of a first electrode plate 110 and a second electrode plate 120 having a thin plate or layer shape and a separator 130 disposed therebetween, or by stacking a plurality of unit stack bodies. When the electrode assembly 100 is formed by winding, the winding axis may extend in a horizontal direction substantially parallel to the longitudinal direction of the cover assembly 300 or in a vertical direction approximately perpendicular to the longitudinal direction of the cover assembly 300. When the electrode assembly 100 is formed by stacking, the long side surfaces of the plurality of unit stack bodies may be arranged adjacent to each other. A sheet 140 made of an insulating material may be attached to the outside of the electrode assembly 100 using an insulating tape 150 to insulate the electrode assembly 100 from the housing 200. For example, the first electrode plate 110 may be a negative electrode, and the second electrode plate 120 may be a positive electrode, and vice versa.

[0045] When the first electrode plate 110 is a negative electrode, the first electrode plate 110 may be formed by applying a first electrode active material (such as graphite or carbon) to a first electrode current collector formed of a metal foil (such as copper, copper alloy, nickel, or nickel alloy). The first electrode plate may have a first uncoated portion as an area where the first electrode active material is not applied. Since the first uncoated portion serves as a tab for electrically connecting to a first current collector plate 330 to be described later, the first uncoated portion may be defined as (or referred to as) a first base tab. A plurality of first base tabs may be bent to one side and welded to the first current collector plate 330. The first current collector plate 330 may be electrically connected to the cover assembly 300.

[0046] When the second electrode plate 120 is a positive electrode, the second electrode plate 120 may be formed by applying a second electrode active material (such as a transition metal oxide) to a second electrode current collector formed of a metal foil (such as aluminum or aluminum alloy). The second electrode plate may have a second uncoated portion 122 as an area where the second electrode active material is not applied. Since the second uncoated portion serves as a tab for electrically connecting to a second current collector plate 340 to be described later, the second uncoated portion may be defined as (or referred to as) a second base tab. A plurality of second base tabs may be bent to one side and welded to the second current collector plate 340. The second current collector plate 340 may be electrically connected to the cover assembly 300.

[0047] The separator 130 may be disposed between the first electrode plate 110 and the second electrode plate 120 to prevent a short circuit between the first electrode plate 110 and the second electrode plate 120 and allow the movement of lithium ions. For example, the separator 130 may include polyethylene, polypropylene, or may be a composite film of polyethylene and polypropylene, but the present disclosure does not limit the material of the separator 130 to the above materials.

[0048] The electrode assembly 100 may be received in the housing 200 together with an electrolyte. In some examples, the electrolyte may include a lithium salt (such as LiPF6 or LiBF4) in an organic solvent (such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC)). The electrolyte may be in a liquid phase or a gel phase.

[0049] Referring Figure 1 , the housing 200 has a generally rectangular box shape with an open upper portion in the longitudinal direction and may have a receiving space formed therein. The electrode assembly 100 and the electrolyte may be received inside the housing 200 through the open upper portion. Some components of the cover assembly 300 may be exposed to the outside of the housing 200, and some components of the cover assembly 300 may be received inside the housing 200. The housing 200 may have a rectangular bottom surface 210 and four side surfaces connected to the bottom surface 210 (e.g., extending from the bottom surface 210). Among the side surfaces, the side surface having a relatively large area is defined as (or referred to as) the long side portion 220, and the side surface having a relatively small area is defined as (or referred to as) the short side portion 230. For example, the electrode assembly 100 may have a plate surface (e.g., a flat or substantially flat surface) arranged to face the long side portion 220. After the electrode assembly 100 is received in the housing 200, the cover assembly 300 is coupled to the housing 200 and electrically connected to the electrode assembly 100.

[0050] Referring Figure 1 and Figure 2 , the cover assembly 300 may include a cover plate 310 coupled to the housing 200, a plurality of insulating members, a first current collector plate 330, a second current collector plate 340, a first terminal portion 350, and a second terminal portion 360.

[0051] The cover plate 310 has a generally rectangular plate shape and may be made of the same material as the housing 200. The cover plate 310 may have terminal holes (e.g., terminal openings) for respectively coupling to the first terminal portion 350 and the second terminal portion 360, a liquid injection hole (e.g., a liquid injection opening) 314, and an exhaust hole (e.g., an exhaust opening) for coupling to the exhaust port 316. In order to insulate the cover plate 310 and the electrode assembly 100 from each other, a plurality of insulating members such as an insulating plate 320 may be provided.

[0052] The first current collector plate 330 electrically connects the first electrode plate 110, which serves as a negative electrode, to the first terminal portion 350. The first current collector plate 330 may be made of the same material as the first electrode plate 110. For example, the first current collector plate 330 may be electrically connected to the first base tab of the first electrode plate 110 by laser welding.

[0053] The second current collector plate 340 may be arranged symmetrically with respect to the first current collector plate 330 and may electrically connect the second electrode plate 120, which serves as a positive electrode, to the second terminal portion 360. The second current collector plate 340 may be made of the same material as the second base tab of the second electrode plate 120.

[0054] The first terminal portion 350 may include a first terminal pin 352 and a first terminal plate 354. The first terminal plate 354 may be insulated from the cover plate 310 by an insulating member 328. The first terminal pin 352 is electrically connected to the first current collector plate 330 and thus electrically connected to the first electrode plate 110 of the electrode assembly 100.

[0055] The second terminal portion 360 may include a second terminal pin 362, a second terminal plate 364, and a conductive plate 366. The second terminal portion 360 may be arranged symmetrically with respect to the first terminal portion 350. The conductive plate 366 electrically connects the second terminal plate 364, which is electrically connected to the second terminal pin 362, to the cover plate 310. Thus, the cover plate 310 is connected to the second current collector plate 340 through the second terminal portion 360 and can thus be electrically connected to the second electrode plate 120. Accordingly, the cover plate 310 has a positive polarity identical to that of the second current collector plate 340, and the housing 200 welded to the cover plate 310 also has a positive polarity.

[0056] When the pressure inside the housing 200 is above the reference pressure, the exhaust port 316 opens (e.g., ruptures) to discharge the gas inside the housing 200 to the outside. The exhaust port 316 may have various structures, such as being fusion-bonded or including a mechanical valve or a thermally actuated device.

[0057] As Figure 4 and Figure 5 shown, according to an embodiment of the present disclosure, the secondary battery may include at least one discharge tube 400 disposed inside the housing 200. Figure 4 is a schematic front view of the discharge tube in the secondary battery according to the embodiment Figure 1 shown, Figure 5 is a schematic front view of the secondary battery Figure 4 shown in which the exhaust port is in an open state. The discharge tube 400 is in the shape of a hollow tube. One end (e.g., the lower end) of the discharge tube 400 is adjacent to the lower surface of the housing 200, and the other end (e.g., the upper end) of the discharge tube 400 communicates with the exhaust port 316 (e.g., is in fluid communication with the exhaust port 316). The lower surface of the housing 200 refers to the lower surface where the electrolyte is collected in the direction of gravity. One end of the discharge tube 400 does not contact the lower surface of the housing 200 but is adjacent to the lower surface of the housing 200 while being spaced apart from the lower surface of the housing 200 by a certain distance. Accordingly, although the exhaust port 316 is positioned at the upper end of the housing 200, the exhaust port 316 communicates with the lower end inside the housing 200.

[0058] Figure 4 and Figure 5 An embodiment is shown in which a discharge pipe 400 is provided, but the present disclosure is not limited thereto. The discharge pipe 400 is installed so as not to interfere with the electrode assembly 100. For example, the discharge pipe 400 can be installed in the space between the electrode assembly 100 and the housing 200. To avoid interfering with the electrode assembly 100, at least a portion of the discharge pipe 400 can be bent due to, for example, the position of the exhaust port 316. For example, when the exhaust port 316 is positioned at the center of the cover plate 310, the discharge pipe 400 can extend downward from the exhaust port 316 until the discharge pipe 400 contacts the electrode assembly 100. Thereafter, the discharge pipe 400 can be bent toward the side surface of the electrode assembly 100 to avoid the electrode assembly 100, and can extend downward along the side surface of the electrode assembly 100 toward the lower surface of the housing 200. However, when the exhaust port 316 is provided at a position corresponding to the space between the electrode assembly 100 and the housing 200 in the cover plate 310, the discharge pipe 400 may not be bent.

[0059] As described above, the discharge pipe 400 is in contact with the electrolyte. Therefore, the discharge pipe 400 can be made of an insulating material that does not react with the electrolyte.

[0060] If gas is generated inside the housing 200 due to electrolyte decomposition, and before thermal runaway occurs and the internal pressure increases, the gas inside the housing 200 pushes the heated residual electrolyte downward, as Figure 4 shown. Therefore, the residual electrolyte flows into the discharge pipe 400 and moves toward the exhaust port 316. Thereafter, when the pressure inside the housing 200 exceeds a reference pressure (e.g., the critical pressure) and the exhaust port 316 opens, the electrolyte is discharged to the outside. As Figure 5 shown, if the electrolyte is continuously discharged through the exhaust port 316, the level (or amount) of the remaining electrolyte in the housing 200 becomes lower than one end of the discharge pipe 400. When most of the remaining electrolyte is discharged, the gas inside the housing 200 can then be discharged to the outside through the discharge pipe 400 following the discharge of the electrolyte.

[0061] In this way, when the pressure inside the housing 200 exceeds the reference pressure, when the exhaust port 316 opens, the residual electrolyte is first discharged, and then the gas is discharged. Therefore, since no or very little residual electrolyte remains in the housing 200, additional decomposition of the residual electrolyte that may occur after the exhaust port opens is avoided or substantially avoided, and thermal runaway caused by such decomposition can be prevented.

[0062] Next, another embodiment of the discharge pipe will be described with reference to Figure 6 the following. Figure 6Is a schematic side view of an exhaust pipe according to another embodiment.

[0063] In this embodiment, the exhaust pipe 1400 may include a connecting pipe 1420 connected to the exhaust port 316 and a plurality of branch pipes 1440 branched from the connecting pipe 1420 and extending toward the lower surface of the housing 200. In this embodiment, the exhaust port 316 is positioned at the center of the cover plate 310. Accordingly, the connecting pipe 1420 may extend downward from the exhaust port 316 until it contacts the electrode assembly 100. Thereafter, the plurality of branch pipes 1440 may be bent from the connecting pipe 1420 toward (or toward) opposite side surfaces of the electrode assembly 100, and then extend downward toward the lower surface of the housing 200.

[0064] When the exhaust pipe 1400 is arranged in this configuration, when the pressure inside the housing 200 exceeds the reference pressure, the exhaust port 316 opens to discharge the remaining electrolyte, and then gas may be discharged.

[0065] In addition, referring to Figure 7 , another embodiment of the exhaust pipe will be described. Figure 7 Is a schematic side view of an exhaust pipe according to yet another embodiment.

[0066] In this embodiment, a plurality of exhaust ports 316 and a plurality of exhaust pipes 2400 are provided, and the corresponding exhaust pipes 2400 may be connected to the corresponding exhaust ports 316. In this embodiment, two exhaust ports 316 are provided, and each exhaust port 316 may be provided on the cover plate 310 at a position corresponding to the space between the electrode assembly 100 and the housing 200. In addition, two exhaust pipes 2400 are provided, and the corresponding exhaust pipes 2400 may extend linearly from the corresponding exhaust ports 316 toward the lower surface of the housing 200. However, the position and number of the exhaust ports 316 may be designed in various ways according to the embodiment.

[0067] When a plurality of exhaust pipes 2400 are arranged in this configuration, when the pressure inside the housing 200 exceeds the reference pressure, the plurality of exhaust ports 316 open to discharge the remaining electrolyte, and then gas is discharged.

[0068] In the above embodiments, a prismatic secondary battery has been described as an example, but the aspects and features of the present disclosure may also be applied to a pouch-type secondary battery.

[0069] Figure 8 Is a schematic side view of an exhaust pipe of a secondary battery according to still another embodiment of the present disclosure. Figure 9 Is Figure 8 A schematic front view of the exhaust pipe of the secondary battery shown in

[0070] Referring to Figure 8 And Figure 9, the pouch-type secondary battery 10a has a recess 210a as an accommodation space. The pouch-type secondary battery 10a may include: a pouch-type case 200a having at least one exhaust port 316a for discharging gas at one side; an electrode assembly 100a accommodated in the recess 210a together with an electrolyte; and at least one discharge pipe 1400a disposed inside the case 200a and having one end adjacent to the lower surface of the recess 210a and the other end communicating with the exhaust port 316a. The electrode assembly 100a may include a first electrode tab 102a electrically connected to a first electrode plate and a second electrode tab 104a electrically connected to a second electrode plate. The exhaust port 316a may be disposed between the first electrode tab 102a and the second electrode tab 104a. The lower surface of the recess 210a refers to the lower surface where the electrolyte is collected in the direction of gravity. In the pouch-type secondary battery 10a, in Figure 6 the structure of the discharge pipe 1400 described in the prismatic battery shown in may be applied to the structure of the discharge pipe 1400a. For example, the discharge pipe 1400a may include a connection pipe 1420a connected to the exhaust port 316a and a plurality of branch pipes 1440a branched from the connection pipe 1420a and extending toward the lower surface of the case 200a. Since the exhaust port 316a is disposed between the first electrode tab 102a and the second electrode tab 104a, the discharge pipe 1400a is also disposed between the first electrode tab 102a and the second electrode tab 104a. The connection pipe 1420a may extend downward from the exhaust port 316a until it contacts the electrode assembly 100a. One of the branch pipes 1440a may be disposed at one side of the electrode assembly 100a and may extend toward the lower surface of the case 200a, and the other of the branch pipes 1440a may pass between the first electrode tab 102a and the second electrode tab 104a and may extend toward the lower surface of the case 200a.

[0071] Figure 10 is a schematic side view of a discharge pipe of a secondary battery according to another embodiment of the present disclosure. Figure 11 is Figure 10 a schematic front view of the discharge pipe of the secondary battery shown in.

[0072] Referring to Figure 10 and Figure 11, the pouch-type secondary battery 10b has a recess 210b as an accommodation space. The pouch-type secondary battery 10b may include: a pouch-type case 200b having at least two exhaust ports 316b for discharging gas on one side; an electrode assembly 100b accommodated in the recess 210b together with an electrolyte; and a plurality of discharge tubes 1400b provided inside the case 200b, each discharge tube 1400b having one end adjacent to the lower surface of the recess 210b and the other end communicating with a corresponding one of the exhaust ports 316b. The electrode assembly 100b may include a first electrode tab 102b electrically connected to the first electrode plate and a second electrode tab 104b electrically connected to the second electrode plate. The exhaust ports 316b may be provided outside the first electrode tab 102b and the second electrode tab 104b. In the pouch-type secondary battery 10b, in Figure 7 The structure of the discharge tube 1400 described in the prismatic battery shown in can be applied to the structure of the discharge tube 1400b in the same manner. For example, in this embodiment, two discharge tubes 1400b may be respectively connected to two exhaust ports 316b. The two discharge tubes 1400b may each extend linearly from the corresponding exhaust port 316b toward the lower surface of the case 200b. The discharge tubes 1400b may be spaced apart from the electrode assembly 100b. The position and number of the exhaust ports 316b may be designed in various suitable ways.

[0073] Therefore, when the pressure inside the case exceeds the reference pressure, the exhaust port opens (e.g., ruptures) to discharge the remaining (or residual) electrolyte before discharging the gas inside the case.

[0074] As described above, according to an embodiment of the present disclosure, by discharging the electrolyte first through the exhaust port before discharging the gas inside the case, decomposition of the remaining electrolyte can be prevented, thereby preventing thermal runaway. Accordingly, rupture and ignition caused by thermal runaway can be prevented.

[0075] The foregoing embodiments are only some embodiments for implementing the secondary battery according to the present disclosure, and the secondary battery according to the present disclosure is not limited to these embodiments. Therefore, those skilled in the art will understand that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A secondary battery, the secondary battery comprising: A prismatic housing; An electrode assembly, accommodated together with an electrolyte inside the housing; A cover assembly, coupled to one end of the housing and having an exhaust port; And A discharge pipe, inside the housing, and having one end adjacent to the lower surface of the housing and the other end communicating with the exhaust port.

2. The secondary battery according to claim 1, wherein When the pressure inside the housing exceeds a reference pressure, the exhaust port opens to discharge the electrolyte, and then gas is discharged from inside the housing.

3. The secondary battery according to claim 2, wherein, The discharge pipe has a hollow tube shape.

4. The secondary battery according to claim 3, wherein The discharge pipe does not interfere with the electrode assembly.

5. The secondary battery according to claim 4, wherein, The discharge pipe has a bent portion.

6. The secondary battery according to claim 5, wherein The discharge pipe includes: A connecting pipe, connected to the exhaust port; and A plurality of branch pipes, branching from the connecting pipe and extending toward the lower surface of the housing.

7. The secondary battery according to claim 5, wherein, The cover assembly includes a plurality of exhaust ports, and Wherein, a plurality of discharge pipes are connected to respective exhaust ports among the plurality of exhaust ports.

8. The secondary battery according to claim 1, wherein The discharge pipe is made of an insulating material that does not react with the electrolyte.

9. A secondary battery, the secondary battery comprising: A pouch-type housing, having a recess and an exhaust port for discharging gas at one side; An electrode assembly, accommodated together with an electrolyte inside the housing; And A discharge pipe, inside the housing, and having one end adjacent to the lower surface of the housing and the other end communicating with the exhaust port.

10. The secondary battery according to claim 9, wherein, When the pressure inside the housing exceeds a reference pressure, the exhaust port opens to discharge the electrolyte, and then gas is discharged from inside the housing.

11. The secondary battery according to claim 10, wherein, The discharge pipe has a hollow tube shape.

12. The secondary battery according to claim 11, wherein, The discharge pipe does not interfere with the electrode assembly.

13. The secondary battery according to claim 12, wherein The discharge pipe has a bent portion.

14. The secondary battery according to claim 13, wherein, The discharge pipe includes: A connecting pipe, connected to the exhaust port; and A plurality of branch pipes, branching from the connecting pipe and extending toward the lower surface of the recess.

15. The secondary battery according to claim 13, wherein, The housing includes a plurality of exhaust ports, and Wherein, a plurality of discharge pipes are connected to respective exhaust ports among the plurality of exhaust ports.

16. The secondary battery according to claim 9, wherein, The discharge pipe is made of an insulating material that does not react with the electrolyte.

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