Bidirectional discharge device and secondary battery including same

Abstract

The present invention relates to a bi-directional discharge device comprising: a rupture disc having a notch portion that ruptures when a pressure exceeding a preset value is applied; and a mounting portion disposed along a periphery of the rupture disk, in which the notch portion includes a first notch portion formed along an edge of the left half portion of the rupture disk, and a second notch portion formed along an edge of the right half portion of the rupture disk, and the second notch part is separated from the first notch part so as not to be connected with the first notch part.

Description

Technical Field

[0001] The present invention relates to a two-way exhaust device and a secondary battery including the same, which improves safety by directing the exhaust of dangerous factors such as high-temperature gas, sparks, heated particles, etc. in a secondary battery that has experienced thermal runaway to the side rather than the top.

[0002] This application claims priority to Korean Patent Application No. 10-2022-0152444, filed on November 15, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] Unlike primary batteries, secondary batteries can be recharged, and due to their potential for miniaturization and large capacity, secondary batteries have been subject to a great deal of research and development in recent years. The demand for secondary batteries as energy sources is rapidly increasing due to technological development and increased demand for mobile devices, electric vehicles, and energy storage systems, which has emerged in response to the need for environmental protection.

[0004] Based on the shape of the battery case, secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries. In the secondary battery, an electrode assembly installed inside the battery case is a chargeable / dischargeable power generation device composed of a laminated structure of electrodes and separators.

[0005] Since secondary batteries need to be used continuously for a long period of time, it is necessary to effectively control the heat generated during the charging and discharging process. If the secondary battery is not properly cooled, the increase in temperature will cause an increase in current, and the increase in current will cause the temperature to rise again, resulting in a feedback chain reaction, which ultimately leads to a catastrophic condition of thermal runaway.

[0006] When thermal runaway occurs in a secondary battery, the temperature and pressure rise together, and if the temperature and pressure rise to a level that exceeds the thermal and pressure performance of the secondary battery, the structure of the secondary battery will eventually collapse. When the structure of the secondary battery collapses, a large amount of air is supplied to the inside, causing the fire or explosion to grow uncontrollably and spread to the surrounding area, resulting in huge damage.

[0007] In order to prevent such structural collapse, secondary batteries, especially cylindrical or prismatic batteries, are usually equipped with a vent, which is a safety valve that releases the pressure inside the secondary battery by rupturing when the pressure exceeds a certain level.

[0008] However, most existing exhaust devices are designed to directly discharge upward hazardous factors such as high temperature gas, sparks, heated particles, etc. When secondary batteries are used in electric vehicles, these exhaust devices may cause safety problems by directing the hazardous factors toward the driver or passengers. Summary of the invention

[0009] Technical issues

[0010] The present invention aims to provide an exhaust device and a secondary battery including the exhaust device, which improves safety by directing the exhaust of dangerous factors such as high-temperature gas, sparks, heated particles, etc. ejected from a secondary battery that has experienced thermal runaway to both sides instead of directly upward.

[0011] However, the technical problems that the present invention seeks to solve are not limited to those mentioned above, and other problems not mentioned will be apparent to those of ordinary skill in the art from the following description of the present invention.

[0012] Technical Solutions

[0013] The present invention relates to a bidirectional discharge device. In one example, the bidirectional discharge device comprises: a rupture disk, which is provided with a notch portion, which ruptures when the pressure exceeds a preset value; and a mounting portion, which is arranged along the boundary of the rupture disk, wherein the notch portion comprises a first notch portion formed along a corner of a left half surface of the rupture disk, and a second notch portion formed along a corner of a right half surface of the rupture disk, and the second notch portion is spaced apart from the first notch portion so as not to be connected to the first notch portion.

[0014] When a pressure exceeding a preset value is applied, the rupture disk ruptures so that the first notch portion and the second notch portion form a butterfly shape.

[0015] In an exemplary embodiment of the present invention, based on an imaginary symmetry line passing through the center where the first and second notch parts are disposed apart from each other, notch depths of the first and second notch parts may increase as distances from the symmetry line increase.

[0016] For example, the first notch portion and the second notch portion may be shaped such that the change in notch depth is linear.

[0017] Furthermore, the farther away from the symmetry line, the greater the rate of change of the notch depths of the first notch portion and the second notch portion.

[0018] Alternatively, as another example, the first notch portion and the second notch portion may be shaped such that a change in notch depth is discontinuous, thereby forming a stepped shape.

[0019] Therefore, the first notch portion and the second notch portion may be ruptured starting from the left and right corners where the notch depth is deeper in a manner proportional to the magnitude of the pressure exceeding the preset value.

[0020] Meanwhile, the present invention provides a secondary battery including: a battery case provided with a space for storing an electrode assembly; and a two-way discharge device installed on at least one side of the battery case.

[0021] The two-way discharge device is airtightly installed so that the first notch portion and the second notch portion are exposed to the outside of the discharge hole formed in the battery case.

[0022] The mounting portion may be fixed to the battery case by welding while being aligned with the drain hole.

[0023] Alternatively, the mounting portion may be provided with a wall-shaped boundary inserted into the discharge hole.

[0024] Furthermore, a support frame may be provided in the mounting portion, the support frame spanning a middle portion where the first recess portion and the second recess portion are disposed apart from each other.

[0025] Beneficial Effects

[0026] According to the two-way discharge device of the present invention having the above-mentioned configuration, the notch portions that rupture when a pressure exceeding a set standard is applied are formed separately from each other along the left and right surface corners of the rupture disk, and therefore, when the rupture disk ruptures, the first notch portion and the second notch portion rupture to form a butterfly shape, so that dangerous factors such as high-temperature gas, sparks, heated particles, etc. are discharged to both sides of the discharge device instead of being discharged directly upward. Therefore, when the discharge device of the present invention is applied to medium and large secondary batteries for automobiles, the discharge device of the present invention can improve safety by discharging dangerous factors toward the sides instead of toward the driver or passengers and directly upward.

[0027] In addition, the two-way discharge device of the present invention allows the notch depth of the notch portion to be formed to be deeper and deeper toward the left and right corners of the rupture disk, so that in the early stage of thermal runaway generated inside the secondary battery, the notch portion can be ruptured to a minimum to discharge only a small amount of ejecta in both directions, thereby suppressing the promotion of combustion by air inflow, while preventing discharge in a direct upward direction as much as possible. In addition, in a state where thermal runaway develops to a final state and rapid pressure release is required, the entire notch portion can be ruptured to ensure the maximum discharge area. Therefore, the two-way discharge device of the present invention can significantly improve the safety of secondary batteries.

[0028] However, the technical effects of the present invention are not limited to those described above, and other effects not mentioned will be apparent to those of ordinary skill in the art from the following description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and are used to further illustrate the technical concept of the present invention in conjunction with the following detailed description of the present invention, and the present invention should not be construed as being limited to the contents shown in these drawings.

[0030] Figure 1 is a diagram illustrating one embodiment of a bidirectional discharge device according to the present invention.

[0031] Figure 2 It is along Figure 1 Cross-sectional view of the cut along the “AA” line.

[0032] Figure 3 is a diagram illustrating a two-way discharge device in a case where a first notch portion and a second notch portion are broken, respectively.

[0033] Figures 4 to 6 The structure of a first notch portion and a second notch portion in a bidirectional discharge device according to another exemplary embodiment of the present invention is illustrated.

[0034] Figure 7 and Figure 8 2 is a diagram illustrating different opening degrees of the first notch portion and the second notch portion.

[0035] Fig. 9 is a diagram illustrating an example in which the two-way discharge device of the present invention is mounted on a secondary battery. DETAILED DESCRIPTION

[0036] The present invention is susceptible of various modifications and may have numerous embodiments, some of which will be described in detail below.

[0037] However, this is not intended to limit the present invention to any specific embodiment, but should be construed to include all modifications, equivalents, or substitutes falling within the scope of the concept and technology of the present invention.

[0038] The terms "including" or "having" are used herein to indicate the presence of features, numbers, steps, actions, parts or components, or a combination thereof, described in the specification, and it should be understood that the presence or possibility of adding one or more other features, numbers, steps, actions, parts, components, or a combination thereof is not precluded.

[0039] In addition, when a portion of a layer, film, region, or plate is disposed "on" another portion, this includes not only a case where one portion is "directly disposed on" another portion, but also a case where a third portion is interposed therebetween. Conversely, when a portion of a layer, film, region, or plate is disposed "below" another portion, this includes not only a case where one portion is "directly disposed below" another portion, but also a case where a third portion is interposed therebetween. In addition, in the present application, "on" may include not only a case where it is disposed on an upper portion, but also a case where it is disposed on a lower portion.

[0040] The present invention relates to a bidirectional discharge device. In one example, the bidirectional discharge device comprises: a rupture disk having a notch portion, which ruptures when a pressure exceeding a preset value is applied; and a mounting portion, which is arranged along the boundary of the rupture disk, wherein the notch portion comprises a first notch portion formed along a corner of a left half surface of the rupture disk, and a second notch portion formed along a corner of a right half surface of the rupture disk, the second notch portion being spaced apart from the first notch portion so as not to be connected to the first notch portion.

[0041] And, when a pressure exceeding a preset value is applied, the rupture disk ruptures the first notch portion and the second notch portion to form a butterfly shape.

[0042] According to the two-way discharge device of the present invention having such a configuration, the notch portions that rupture when a pressure exceeding the standard is applied are formed separately from each other along the left-half surface corner and the right-half surface corner of the rupture disk, so that when the rupture disk ruptures, the first notch portion and the second notch portion rupture in a butterfly shape, so that dangerous factors such as high-temperature gas, flame, heated particles, etc. are discharged to both sides of the discharge device instead of being discharged directly upward.

[0043] Therefore, when the discharge device of the present invention is applied to a medium to large-sized secondary battery for an automobile, the discharge device of the present invention can improve safety by directing dangerous factors to the side instead of toward a driver or a passenger, directly upward.

[0044] Mode for carrying out the invention

[0045] Hereinafter, with reference to the accompanying drawings, a specific embodiment of a bidirectional discharge device 100 according to the present invention and a secondary battery 200 including the same will be described in detail. For reference, unless otherwise specified, the directions of front, rear, up, down, left, and right indicating relative positions used in the following description are intended to help understand the present invention and refer to the directions shown in the drawings.

[0046] [First embodiment]

[0047] Figure 1is a diagram illustrating one embodiment of a bidirectional discharge device 100 according to the present invention, and Figure 2 is through along Figure 1 Cross-sectional view of the cut along line "AA".

[0048] The illustrated present invention is a bidirectional discharge device 100 , which includes a rupture disk 110 having a notch 112 that ruptures when a pressure exceeding a preset value is applied, and a mounting portion 120 disposed along a boundary of the rupture disk 110 .

[0049] The rupture disk 110 is a thin plate-shaped member made of metal, on the surface of which a notched notch portion 112 is formed. The two-way discharge device 100 is mounted on the secondary battery 200, and when the internal pressure of the sealed battery case 210 increases, the pressure causes tensile deformation on the thin rupture disk 110, and then the tensile deformation of the rupture disk 110 causes the weaker notch portion 112 to tear open to release the internal pressure of the battery case 210.

[0050] The mounting portion 120 is a boundary portion where the two-way discharge device 100 is coupled to the battery case 210 of the secondary battery 200, and is also used to structurally support the rupture disk 110. The mounting portion 120 may be shaped in various ways, such as in the form of a plate thicker than the rupture disk 110, or in the form of a well having a protruding side wall 122 surrounding the rupture disk 110.

[0051] Here, the bidirectional discharge device 100 of the present invention includes a pair of notches 112-1, 112-2, wherein the notches 112 are independent of each other. Specifically, the notches 112 of the present invention include a first notch 112-1 formed along the left half surface corner of the rupture disk 110 and a second notch 112-2 formed along the right half surface corner of the rupture disk 110, and the second notch 112-2 is spaced apart from the first notch 112-1 so as not to be connected to the first notch 112-1.

[0052] Reference Figure 2, the first notch portion 112-1 and the second notch portion 112-2 are separated from each other with respect to an imaginary symmetry line SL that passes approximately through the center of the rupture disk 110. That is, since there is no notch in the central region of the rupture disk 110 that separates the first notch portion 112-1 and the second notch portion 112-2, the original thickness of the rupture disk 110 is maintained, and the first notch portion 112-1 and the second notch portion 112-2 are formed by performing notching in the form of lines along the left and right half surface corners of the rupture disk 110, respectively. Since the thin first notch portion 112-1 and the second notch portion 112-2 have a lower rupture strength than other portions of the rupture disk 110, rupture occurs in the rupture disk 110 along the first notch portion 112-1 and the second notch portion 112-2 when a pressure exceeding a prescribed level is applied.

[0053] Figure 3 1 is a diagram illustrating the two-way discharge device 100 in the case where the first notch portion 112-1 and the second notch portion 112-2 are ruptured, respectively. As shown, when the rupture occurs along the first notch portion 112-1 and the second notch portion 112-2 in the form of a U-shaped line, the first notch portion 112-1 and the second notch portion 112-2 are lifted upward by the pressure from the inside, wherein the central area of ​​the rupture disk 110 that separates the first notch portion 112-1 and the second notch portion 112-2 serves as a support portion. In other words, when a pressure exceeding a preset value is applied to the two-way discharge device 100, the rupture disk 110 ruptures in both the left and right directions, so that the first notch portion 112-1 and the second notch portion 112-2 form a butterfly shape, and therefore, the gas or sparks ejected from the inside of the secondary battery 200 equipped with the two-way discharge device 100 are discharged to the side at a certain angle, rather than being discharged directly upward.

[0054] [Second Embodiment]

[0055] Figures 4 to 6 The second embodiment of the bidirectional discharge device 100 of the present invention is shown in FIG. Figure 2 A cross-sectional view in a cutting plane of the first notch portion 112 - 1 and the second notch portion 112 - 2 is shown.

[0056] In the second embodiment shown, the first notch portion 112-1 and the second notch portion 112-2 are configured such that the depth of the notch increases with increasing distance from an imaginary symmetry line SL passing through the centers of the separately disposed ends of the rupture disk 110, i.e., the notch is deepest at the left and right half ends of the rupture disk 110.

[0057] According to the second embodiment, when a pressure exceeding a preset value is applied to the rupture disk 110, the first notch portion 112-1 and the second notch portion 112-2 begin to rupture from the left and right corners having deeper notches in a manner proportional to the magnitude of the applied pressure. That is, the deeper the notch, the lower the rupture strength, so that when a pressure exceeding the standard is applied, the left and right corners having deeper notches rupture first.

[0058] Furthermore, if the pressure acting on the rupture disk 110 is sufficient to rupture the thinnest left corner of the first notch portion 112-1 and the thinnest right corner of the second notch portion 112-2, but insufficient to rupture the thicker portion, the first notch portion 112-1 and the second notch portion 112-2 may not rupture in their entirety, but only a portion of the left and right corners may rupture. In other words, the second embodiment is configured so that the first notch portion 112-1 and the second notch portion 112-2 can rupture only a portion thereof, and the degree of opening of the first notch portion 112-1 and the second notch portion 112-2 increases in proportion to the applied pressure.

[0059] According to such a second embodiment, when the internal pressure gradually increases as the thermal runaway inside the secondary battery 200 equipped with the two-way discharge device 100 develops, the opening degree of the first notch portion 112-1 and the second notch portion 112-2 gradually increases in response to the rising pressure level. Therefore, in the early stage of thermal runaway, the first notch portion 112-1 and the second notch portion 112-2 are ruptured in a small manner so that only a small amount of ejecta can be discharged in two directions, thereby suppressing the promotion of combustion by the inflow of air while preventing the discharge in the direct upward direction as much as possible.

[0060] Furthermore, in the event that thermal runaway has developed to a final state and rapid pressure discharge is required, the entire first notch portion 112 - 1 and the second notch portion 112 - 2 may be ruptured to provide a maximum discharge area. Figure 7 and Figure 8 Two states in which the degree of opening varies according to the degree of rupture of the first notch portion 112 - 1 and the second notch portion 112 - 2 are exemplarily illustrated. Figure 8 The status and Figure 7 Compared with the state in , the pressure acting on the rupture disk 110 is higher and the entire first notch portion 112-1 and the second notch portion 112-2 are ruptured to achieve the maximum opening.

[0061] at the same time, Figures 4 to 6 A different form is illustrated in which the thicknesses of the first notch portion 112 - 1 and the second notch portion 112 - 2 are gradually reduced toward the left and right corners.

[0062] Figure 4 and Figure 5 An embodiment is illustrated in which the changes in the notch depths of the first notch portion 112-1 and the second notch portion 112-2 are linear in shape. Figure 4 In the embodiment of , with respect to an imaginary symmetry line SL passing through the centers of the first notch portion 112-1 and the second notch portion 112-2 spaced apart from each other on the rupture disk 110, the notch depth increases in a straight line of a first-order function as the distance from the symmetry line SL increases. Figure 5 In an embodiment of the present invention, the notch depth varies linearly, wherein the difference is that the rate of change of the notch depth is in the form of a curve that increases with increasing distance from the symmetry line SL, rather than in the form of a straight line of a first-order function.

[0063] Figure 5 The embodiment is intended to further ensure that the first notch portion 112-1 and the second notch portion 112-2 gradually rupture in proportion to the internal pressure. Figure 4 As shown, if the change in the notch depth forms a straight line of a first-order function, the first notch portion 112-1 and the second notch portion 112-2 may break more than expected due to inertia when they start to break. Figure 5 This is an embodiment that effectively prevents such excessive rupture, in which the left corner of the first notch portion 112-1 and the right corner of the second notch portion 112-2 are easily ruptured at the beginning of rupture, but as the rupture develops toward the center, the thickness increases rapidly to prevent excessive rupture from occurring.

[0064] Figure 6 is achieved with Figure 5 The configuration of the first notch portion 112-1 and the second notch portion 112-2 has the same effect as the embodiment of the present invention, wherein the change in notch depth is in the form of discontinuous steps. Since each step with discontinuously changing notch depth leads to discontinuous fracture strength, the first notch portion 112-1 and the second notch portion 112-2 are gradually fractured in response to the increase in pressure, and the possibility of excessive fracture is greatly reduced.

[0065] [Third Embodiment]

[0066] Fig. 9 1 is a diagram illustrating an example in which the two-way discharge device 100 of the present invention is mounted to a secondary battery 200. The secondary battery 200 includes a battery case 210 having a space for storing an electrode assembly 220, and at least one two-way discharge device 100 may be mounted on at least one side (top side in the figure) of the battery case 210.

[0067] The two-way discharge device 100 is airtightly installed so that the first notch portion 112-1 and the second notch portion 112-2 are exposed to the outside relative to the discharge hole 212 formed in the battery case 210. That is, the first notch portion 112-1 and the second notch portion 112-2 are fully exposed so as to be observed from the outside, so that the first notch portion 112-1 and the second notch portion 112-2 are broken to form a Figure 3 The butterfly shape is shown without obstruction or interference.

[0068] Also, the mounting portion 120 for fixing the two-way drain device to the battery case 210 may be welded to the battery case 210 in alignment with the drain hole 212 formed through the battery case 210. Fig. 9 In the illustrated embodiment, the mounting portion 120 protrudes in the form of a well-shaped portion to form a boundary in the form of a wall 122 abutting against the rupture disk 110, through which the side wall 122 of the mounting portion 120 can be inserted into the discharge hole 212 to be coupled. Of course, the side wall 122 of the mounting portion 120 can also be welded around the discharge hole 212 to increase the strength of the fixation.

[0069] And, if Fig. 9 As shown in the partial enlarged view of , the mounting portion 120 may include a support frame 124 that spans the center where the first notch portion 112-1 and the second notch portion 112-2 are separated from each other. The support frame 124 reliably prevents the rupture of each of the first notch portion 112-1 and the second notch portion 112-2 from affecting each other, thereby further ensuring that the ruptured first notch portion 112-1 and the second notch portion 112-2 will form a butterfly shape, so that high-temperature gas, dust, etc. can be discharged in both directions.

[0070] The present invention has been described in more detail above with reference to the accompanying drawings and embodiments. However, it will be understood that the configuration shown in the accompanying drawings or embodiments described herein is only one embodiment of the present invention and does not represent all technical ideas of the present invention, and when submitting this application, there may be various equivalents and modifications that can replace these configurations.

[0071] Reference numerals

[0072] 100: Two-way discharge device 110: Rupture disk

[0073] 112: Notch portion 112-1: First notch portion

[0074] 112-2: Second notch portion 120: Mounting portion

[0075] 122: Side wall 124: Support frame

[0076] 200: Secondary battery 210: Battery case

[0077] 212: discharge hole 220: electrode assembly

[0078] SL: Symmetry Line

Claims

1. A two-way discharge device, comprising: a rupture disk, the rupture disk being provided with a notched portion, the notched portion rupturing when the pressure exceeds a preset value; as well as A mounting portion is provided along a boundary of the rupture disk, wherein: The notch portion comprises: A first notch portion is formed along a left half surface corner of the rupture disk, and a second notch portion is formed along a right half surface corner of the rupture disk, the second notch portion being spaced apart from the first notch portion so as not to be connected to the first notch portion.

2. The two-way discharge device according to claim 1, wherein: When a pressure exceeding a preset value is applied, the rupture disk ruptures, so that the first notch portion and the second notch portion form a butterfly shape.

3. The two-way discharge device according to claim 2, wherein: Based on an imaginary symmetry line passing through a center where the first notch portion and the second notch portion are disposed apart from each other, notch depths of the first notch portion and the second notch portion increase as a distance from the symmetry line increases.

4. The two-way discharge device according to claim 3, wherein: The first notch portion and the second notch portion are shaped such that a variation in the notch depth is linear.

5. The two-way discharge device according to claim 4, wherein: The farther away from the symmetry line, the greater the rate of change of the notch depths of the first notch portion and the second notch portion.

6. The two-way discharge device according to claim 3, wherein: The first and second notch portions are shaped such that a change in the notch depth is discontinuous, thereby forming a stepped shape.

7. The two-way discharge device according to claim 3, wherein: The first notch portion and the second notch portion are broken from left and right corners where the notch depth is deeper in proportion to the magnitude of the pressure exceeding the preset value.

8. A secondary battery comprising: A battery box, wherein the battery box is provided with a space for storing the electrode assembly; as well as A two-way discharge device according to any one of claims 1 to 7, wherein the device is mounted on at least one side of the battery box.

9. The secondary battery according to claim 8, wherein The two-way discharge device is airtightly installed so that the first notch portion and the second notch portion are exposed to the outside of a discharge hole formed in the battery case.

10. The secondary battery according to claim 9, wherein The mounting portion is fixed to the battery case by welding while being aligned with the discharge hole.

11. The secondary battery according to claim 9, wherein The mounting portion is provided with a wall-shaped boundary inserted into the discharge hole.

12. The secondary battery according to claim 11, wherein A support frame is provided in the mounting portion, the support frame spanning a middle portion where the first recess portion and the second recess portion are disposed apart from each other.

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