Relief valve and battery pack including same

Abstract

The technical idea of ​​the present invention provides a battery pack including: a pack housing having an internal space in which battery cells are accommodated; and a relief valve attached to the pack housing, wherein the relief valve includes: a fixing frame attached to the pack housing and having a venting passage communicating with the internal space of the pack housing; a valve cover configured to move between an open position at which the venting passage of the fixing frame is opened to an external space outside the pack housing and a closed position at which the venting passage of the fixing frame is closed to the external space in response to a pressure in the internal space of the pack housing; and a mesh plate coupled to the valve cover to move together with the valve cover and having a plurality of venting holes, wherein when the valve cover is in the open position, the internal space of the pack housing communicates with the external space via the plurality of venting holes in the mesh plate.

Description

[Technical Field]

[0001] The present invention relates to a relief valve and a battery pack including the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0175078, filed December 6, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of wireless devices, such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0004] As secondary batteries are used in mobility, there is a growing demand for their safety. Research into technologies to improve the safety of secondary batteries is essential, as a fire or other accident involving a secondary battery used in mobility could put the driver's life at risk. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem that the present invention aims to achieve is to provide a relief valve and a battery pack including the same. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a battery pack including: a pack housing having an internal space in which battery cells are accommodated; and a relief valve attached to the pack housing, wherein the relief valve has a venting passage communicating with the internal space of the pack housing; a fixing frame attached to the pack housing and having a venting passage communicating with the internal space of the pack housing; a valve cover configured to move between an open position at which the venting passage of the fixing frame is opened to an external space outside the pack housing and a closed position at which the venting passage of the fixing frame is closed to the external space in response to a pressure in the internal space of the pack housing; and a mesh plate coupled to the valve cover to move together with the valve cover and having a plurality of venting holes, wherein when the valve cover is in the open position, the internal space of the pack housing is in communication with the external space via the plurality of venting holes in the mesh plate.

[0007] In an exemplary embodiment, the width of each of the plurality of venting holes is equal to or greater than 0.01 mm and less than 0.61 mm.

[0008] In an exemplary embodiment, the mesh plate extends continuously along the edge of the valve lid.

[0009] In an exemplary embodiment, when the valve cover is in the closed position, the mesh plate is surrounded by an edge wall of the fixed frame and is not exposed to the external space, and when the valve cover is in the open position, the mesh plate protrudes from the fixed frame and is exposed to the external space.

[0010] In an exemplary embodiment, the relief valve is characterized by further including a spring configured to provide a restoring force to the valve lid in a direction from the open position toward the closed position.

[0011] In an exemplary embodiment, the valve lid is characterized by including a moving rod around which the spring is wrapped.

[0012] In an exemplary embodiment, the fixed frame is characterized by including a ring-shaped body fixed to the housing and a support structure extending from the ring-shaped body toward the moving rod and supporting the sides of the moving rod.

[0013] In an exemplary embodiment, the spring is provided between a catch lug at the end of the moving rod and the support structure.

[0014] In an exemplary embodiment, the valve lid is characterized by linear movement between the closed and open positions.

[0015] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a relief valve including: a fixed frame having a venting passage; a valve cover movably attached to the fixed frame and configured to move between a closed position at which the venting passage of the fixed frame is closed and an open position at which the venting passage of the fixed frame is opened; and a mesh plate connected to the valve cover so as to move together with the valve cover and having a plurality of venting holes, wherein when the valve cover is in the open position, the venting passage of the fixed frame communicates with an external space via the plurality of venting holes of the mesh plate.

[0016] In an exemplary embodiment, the width of each of the plurality of venting holes is equal to or greater than 0.01 mm and less than 0.61 mm.

[0017] In an exemplary embodiment, the valve cover further includes a spring configured to provide a restoring force to the valve cover in a direction from the open position toward the closed position, the valve cover including a blocking plate covering the vent passage of the fixed frame and a moving rod connected to the blocking plate, and the spring is wound around the moving rod.

[0018] In an exemplary embodiment, the mesh plate is characterized by having a tubular shape that extends continuously along the edge of the blocking plate.

[0019] In an exemplary embodiment, the fixed frame includes a ring-shaped body having a hollow portion, and a support structure extending from the ring-shaped body toward the moving rod and supporting the side of the moving rod, wherein one end of the spring is supported by a hooking protrusion of the moving rod, and the other end of the spring is supported by the support structure.

[0020] In an exemplary embodiment, the ring-shaped body includes an edge wall that surrounds the mesh plate when the valve cover is in the closed position. [Effects of the Invention]

[0021] According to an exemplary embodiment of the present invention, the mesh plate of the relief valve includes a venting hole having a dimension for blocking the discharge of spark particles, thereby preventing spark particles generated within the battery pack from escaping to the external space. This eliminates an ignition source, which is one of the three elements of a fire, thereby suppressing the occurrence of a fire around the battery pack and improving the safety of the battery pack and the device including the battery pack.

[0022] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects described above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a perspective view of a relief valve in a closed state according to an exemplary embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a relief valve in an open state according to an exemplary embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional perspective view of a relief valve in an open state according to an exemplary embodiment of the present invention. [Figure 4] FIG. 1 is a perspective view of a battery pack according to an exemplary embodiment of the present invention. [Figure 5] FIG. 2 is a cross-sectional view of the battery pack, schematically illustrating a state in which a relief valve of the battery pack is in a closed state. [Figure 6] FIG. 2 is a cross-sectional view of the battery pack, schematically illustrating a state in which a relief valve of the battery pack is in an open state. [Figure 7] FIG. 4 is a cross-sectional view showing a mesh plate of the battery pack. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As a premise, the terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of terms in order to best describe his / her own invention.

[0025] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0026] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0027] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or illustrated schematically for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0028] (First embodiment) 1 to 3 are drawings showing a relief valve 100 according to an exemplary embodiment of the present invention, in which FIG. 1 is a perspective view showing the relief valve 100 in a closed state, FIG. 2 is a perspective view showing the relief valve 100 in an open state, and FIG. 3 is a cross-sectional perspective view showing a cross section of the relief valve 100 in the open state.

[0029] 1 to 3, a relief valve 100 may be mounted in a housing having a sealed interior space. The relief valve 100 may be configured to switch between a closed state and an open state depending on the pressure in the interior space of the housing.

[0030] When the relief valve 100 is in a closed state, the relief valve 100 can close the passage between the interior space of the housing and an external space outside the housing or outside the relief valve 100, thereby blocking the flow of gas between the external space and the interior space of the housing. When the relief valve 100 is in an open state, the relief valve 100 can open the passage between the external space and the interior space of the housing, thereby allowing the flow of gas between the external space and the interior space of the housing.

[0031] When the pressure in the internal space of the housing is equal to or lower than a preset reference value, the relief valve 100 may be in a closed state, and when the pressure in the internal space of the housing exceeds the preset reference value, the relief valve 100 may be in an open state. When the pressure in the internal space of the housing exceeds the preset reference value, the relief valve 100 may be in an open state, allowing gas in the internal space of the housing to be released to the outside space, thereby relieving the pressure in the internal space of the housing. When the pressure in the internal space of the housing is relieved and the pressure in the internal space of the housing becomes equal to or lower than the preset reference value, the relief valve 100 may be switched from an open state to a closed state.

[0032] The relief valve 100 may include a stationary frame 110 , a valve lid 120 , a mesh plate 130 , and a spring 140 .

[0033] The fixed frame 110 may be attached to and fixed to the housing. The fixed frame 110 may have a vent passage 111 that communicates with the interior space of the housing. The vent passage 111 of the fixed frame 110 may communicate the interior space of the housing with the exterior space.

[0034] The stationary frame 110 may include a ring-shaped body 113 coupled to the housing and a support structure 115 extending inwardly from the ring-shaped body 113. The venting passage 111 of the stationary frame 110 may include a hollow portion of the ring-shaped body 113.

[0035] The valve lid 120 can be switched between a closed position and an open position depending on the pressure in the interior space of the housing. When the relief valve 100 is in a closed state, the valve lid 120 can be in a closed position. When the relief valve 100 is in an open state, the valve lid 120 can be in an open position. The valve lid 120 can move linearly between the open position and the closed position.

[0036] When the valve lid 120 is in the closed position, the valve lid 120 can close the vent passage 111 of the fixed frame 110 to the external space so that the vent passage 111 of the fixed frame 110 does not communicate with the external space. When the valve lid 120 is in the closed position, the flow of gas between the internal space of the housing and the external space can be blocked.

[0037] When the valve lid 120 is in the open position, the valve lid 120 can open the vent passage 111 of the fixed frame 110 to the exterior space so that the vent passage 111 of the fixed frame 110 communicates with the exterior space. When the valve lid 120 is in the open position, gas can flow from the interior space of the housing to the exterior space through the vent passage 111 of the fixed frame 110.

[0038] The valve cover 120 may include a blocking plate 121 that covers and closes the venting passage 111 of the fixed frame 110, and a moving rod 123 coupled to the blocking plate 121. The support structure 115 extends from the ring-shaped body 113 toward the moving rod 123 and may support the sides of the moving rod 123 so that the moving rod 123 moves linearly along a predetermined path.

[0039] The mesh plate 130 is coupled to the valve cover 120 and can move together with the valve cover 120 when the valve cover 120 moves. The mesh plate 130 can be coupled to the edge of the valve cover 120. More specifically, the mesh plate 130 can be coupled to the edge of the blocking plate 121 of the valve cover 120 and can have a ring or tube shape that extends continuously along the edge of the blocking plate 121 of the valve cover 120.

[0040] When the valve cover 120 is in the closed position, the mesh plate 130 may be surrounded by the edge wall 114 of the fixed frame 110 and not exposed to the outside space. When the valve cover 120 is in the open position, the mesh plate 130 may protrude from the fixed frame 110 and be exposed to the outside space.

[0041] The mesh plate 130 may include a plurality of venting holes (131 in FIG. 7). The plurality of venting holes 131 may be regularly arranged within the mesh plate 130. Each venting hole 131 may be circular or polygonal. When the valve cover 120 is switched from the closed position to the open position, the mesh plate 130 protrudes from the fixed frame 110 and may be positioned between the venting passage 111 of the fixed frame 110 and the external space. When the valve cover 120 is in the open position, the venting passage 111 of the fixed frame 110 may communicate with the external space through the plurality of venting holes 131 of the mesh plate 130. As shown in FIG. 3, the venting gas within the housing flows to the external space through the venting passage 111 of the fixed frame 110 and the venting holes 131 of the mesh plate 130. The venting gas flow path GP may be approximately perpendicular to the direction of movement of the valve cover 120.

[0042] The spring 140 can provide a restoring force to the valve cover 120 in a direction from the open position to the closed position of the valve cover 120. For example, the spring 140 can be a coil spring wound around the moving rod 123. The spring 140 can be provided between the support structure 115 of the fixed frame 110 and the hooking protrusion 125 of the moving rod 123 at the end of the moving rod 123. One end of the spring 140 can be supported by the hooking protrusion 125 of the moving rod 123, and the other end of the spring 140 can be supported by the support structure 115. When the pressure in the internal space of the housing is equal to or lower than a preset reference value, the valve cover 120 can be elastically supported by the spring 140 and fixed in the closed position. When the pressure in the internal space of the housing exceeds the preset reference value, the valve cover 120 can gradually move from the closed position to the open position.

[0043] (Second embodiment) Figures 4 to 7 are drawings showing a battery pack 10 according to an exemplary embodiment of the present invention, where Figure 4 is an oblique view showing the battery pack 10, Figure 5 is a cross-sectional view of the battery pack 10 schematically showing the relief valve 100 of the battery pack 10 in a closed state, Figure 6 is a cross-sectional view of the battery pack 10 schematically showing the relief valve 100 of the battery pack 10 in an open state, and Figure 7 is a cross-sectional view showing the mesh plate 130 of the battery pack 10.

[0044] 4 to 7, the battery pack 10 can include a pack housing 210, a battery cell assembly 230, and a relief valve 100. For the relief valve 100, please also refer to FIGS.

[0045] The pack housing 210 may provide a sealed interior space 220. The pack housing 210 may include a lower housing 211 that defines the interior space 220, and a pack lid 215 that is coupled to the lower housing 211 to cover the interior space 220 of the lower housing 211. The lower housing 211 may include a bottom plate and a sidewall coupled to an edge of the bottom plate.

[0046] Battery cell assemblies 230 may be provided within the interior space 220 of the pack housing 210. The battery cell assemblies 230 may correspond to a battery module or a cell-to-pack structure. The battery pack 10 may include one or more battery cell assemblies 230. In an exemplary embodiment, the battery pack 10 may include a plurality of battery cell assemblies 230 arranged in a first horizontal direction (e.g., an X direction) and a second horizontal direction (e.g., a Y direction).

[0047] The battery cell assembly 230 may include multiple battery cells. Each battery cell is the basic unit of a lithium-ion battery, i.e., a secondary battery. Each battery cell may include an electrode assembly, an electrolyte, and a cell case. The electrode assembly housed in the cell case may include a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. Depending on the assembly form, the electrode assembly may be either a jelly roll type or a stack type. A jelly roll type electrode assembly may include a wound structure of a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly may include multiple positive electrodes, multiple negative electrodes, and multiple separators interposed therebetween, stacked in sequence. The positive electrode may include a positive electrode current collector and a positive electrode active material. The negative electrode may include a negative electrode current collector and a negative electrode active material.

[0048] The plurality of battery cells may be connected in series and / or parallel. In one example, the plurality of battery cells may be connected in series with each other. In one example, the plurality of battery cells may be connected in parallel with each other. In one example, when a set of two or more battery cells connected in parallel with each other is defined as a bank, one bank consisting of two or more battery cells connected in parallel with each other and another bank consisting of two or more battery cells connected in parallel with each other may be connected in series.

[0049] The individual battery cells may be pouch-type, cylindrical, or prismatic battery cells. The electrode assembly of a pouch-type battery cell is housed in a pouch cell case including an aluminum laminate sheet. The electrode assembly of a cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of a prismatic battery cell is housed in a prismatic metal can.

[0050] The relief valve 100 can be attached to the pack housing 210. In the exemplary embodiment, the lower housing 211 has a through-hole 211H that communicates with the internal space 220 of the pack housing 210, and the relief valve 100 can be attached to the through-hole 211H in the side wall of the lower housing 211.

[0051] The relief valve 100 can be switched between an open position that opens the vent passage 111 of the fixed frame 110 to the external space ES outside the pack housing 210 and a closed position that closes the vent passage 111 of the fixed frame 110 to the external space ES, depending on the pressure in the internal space 220 of the pack housing 210. When the pressure in the internal space 220 of the pack housing 210 is equal to or lower than a preset reference value, the valve cover 120 is elastically supported by the spring 140 and positioned in the closed position, so that the vent passage 111 of the fixed frame 110 does not communicate with the external space ES and the flow of gas between the internal space 220 of the pack housing 210 and the external space ES is blocked. When the pressure in internal space 220 of pack housing 210 exceeds a preset reference value, valve lid 120 moves from the closed position toward the open position, venting passage 111 of fixing frame 110 communicates with external space ES, and gas in internal space 220 of pack housing 210 can be discharged to external space ES through venting passage 111 of fixing frame 110. When the pressure in internal space 220 of pack housing 210 is relieved and falls below the preset reference value, valve lid 120 is fixed in the closed position by the restoring force of spring 140.

[0052] When the valve lid 120 is in the open position, the mesh plate 130 is positioned between the vent passage 111 of the fixed frame 110 and the external space ES, and the internal space 220 of the pack housing 210 can communicate with the external space ES through the multiple vent holes 131 of the mesh plate 130 and the vent passage 111 of the fixed frame 110. When the valve lid 120 is in the open position, gas in the internal space 220 of the pack housing 210 can be released to the external space ES through the vent passage 111 of the fixed frame 110 and the multiple vent holes 131 of the mesh plate 130. When the valve lid 120 is in the closed position, the mesh plate 130 is surrounded by the edge wall 114 of the fixed frame 110 and is not exposed to the external space ES.

[0053] Generally, spark particles SP generated at the cell level due to a short circuit between the positive and negative electrodes become an ignition source that causes a flame. Specifically, oxygen, venting gas generated by vaporization of the electrolyte, and spark particles SP are the three elements of a flame. When the spark particles SP and venting gas generated within the battery pack 10 are released into the external space ES, the spark particles SP, venting gas, and oxygen in the external space ES meet, which can cause a flame around the battery pack 10.

[0054] In an exemplary embodiment, the width W1 of the venting hole 131 may be less than 0.61 mm. Here, the width W1 of the venting hole 131 may refer to the maximum width or diameter of the venting hole 131. If the width W1 of the venting hole 131 is 0.61 mm or greater, spark particles SP generated at the cell level due to a short circuit between the positive and negative electrodes may escape into the external space ES, where they may encounter venting gas and oxygen, causing a fire around the battery pack 10. Therefore, by configuring the width W1 of the venting hole 131 to be less than 0.61 mm, the spark particles SP in the battery pack 10 can be prevented from escaping to the external space ES through the relief valve 100 and can remain within the pack housing 210. When the spark particles SP are prevented from escaping to the external space ES, they are prevented from encountering oxygen, thereby suppressing the occurrence of a fire around the battery pack 10.

[0055] In an exemplary embodiment, the width W1 of the venting hole 131 may be 0.01 mm or greater. If the width W1 of the venting hole 131 is smaller than 0.01 mm, the gas exhaust flow rate through the venting hole 131 may be too small, and the exhaust efficiency through the relief valve 100 may decrease.

[0056] In an exemplary embodiment, the width W1 of the venting hole 131 may be 0.01 mm or more and less than 0.61 mm, or may be 0.01 mm or more and 0.59 mm or less, 0.01 mm or more and 0.57 mm or less, 0.01 mm or more and 0.55 mm or less, 0.01 mm or more and 0.53 mm or less, 0.01 mm or more and 0.51 mm or less, 0.01 mm or more and 0.49 mm or less, 0.01 mm or more and 0.47 mm or less, 0.01 mm or more and 0.45 mm or less, or 0.01 mm or more and 0.43 mm or less.

[0057] According to an exemplary embodiment of the present invention, mesh plate 130 of relief valve 100 includes venting holes 131 having dimensions for blocking the discharge of spark particles SP, thereby preventing spark particles SP generated within battery pack 10 from escaping into external space ES. This can eliminate an ignition source, which is one of the three elements of a flame, thereby suppressing the occurrence of a flame around battery pack 10 and improving the safety of battery pack 10 and devices including the same.

[0058] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, at the time of filing this application, there may be various equivalents and modifications that can replace them.

Claims

1. a pack housing having an internal space in which the battery cells are housed; a relief valve attached to the pack housing; Including, The relief valve is a stationary frame attached to the pack housing, the stationary frame having a venting passage communicating with the interior space of the pack housing; a valve cover configured to move between an open position at which the vent passage of the stationary frame is opened to an external space outside the pack housing and a closed position at which the vent passage of the stationary frame is closed to the external space in response to a pressure in the internal space of the pack housing; a mesh plate coupled to the valve cover for movement therewith, the mesh plate having a plurality of venting holes; Including, When the valve cover is in the open position, the interior space of the pack housing communicates with the exterior space through the plurality of venting holes in the mesh plate.

2. The battery pack according to claim 1 , wherein the width of each of the plurality of venting holes is equal to or greater than 0.01 mm and less than 0.61 mm.

3. The battery pack according to claim 1 , wherein the mesh plate extends continuously along an edge of the valve lid.

4. When the valve cover is in the closed position, the mesh plate is surrounded by an edge wall of the fixed frame and is not exposed to the external space; The battery pack according to claim 1 , wherein when the valve cover is in the open position, the mesh plate protrudes from the fixed frame and is exposed to the external space.

5. The battery pack of claim 1 , wherein the relief valve further includes a spring configured to provide a restoring force to the valve lid in a direction from the open position toward the closed position.

6. The battery pack of claim 5 , wherein the valve lid includes a moving rod around which the spring is wound.

7. The fixed frame is a ring-shaped body fixed to the pack housing; a support structure extending from the ring-shaped body toward the moving rod and supporting the sides of the moving rod; 7. The battery pack of claim 6, comprising:

8. The battery pack according to claim 7 , wherein the spring is provided between a hooking protrusion at the end of the moving rod and the support structure.

9. The battery pack of claim 1 , wherein the valve lid moves linearly between the closed position and the open position.

10. a stationary frame having a venting passage; a valve cover movably attached to the stationary frame and configured to move between a closed position that closes the vent passage of the stationary frame and an open position that opens the vent passage of the stationary frame; a mesh plate coupled to the valve cover for movement therewith, the mesh plate having a plurality of venting holes; Including, When the valve cover is in the open position, the vent passage of the fixed frame communicates with an external space through the plurality of vent holes of the mesh plate.

11. 11. The relief valve according to claim 10, wherein a width of each of the plurality of venting holes is equal to or greater than 0.01 mm and less than 0.61 mm.

12. a spring configured to provide a restoring force to the valve cap in a direction from the open position toward the closed position; The valve cover includes a blocking plate that covers the vent passage of the fixed frame, and a moving rod connected to the blocking plate. The relief valve of claim 10, wherein the spring is wound around the moving rod.

13. 13. The relief valve according to claim 12, wherein the mesh plate has a tubular shape that extends continuously along the edge of the shutoff plate.

14. The fixed frame is a ring-shaped main body having a hollow portion; a support structure extending from the ring-shaped body toward the moving rod and supporting the sides of the moving rod; Including, 14. The relief valve according to claim 13, wherein one end of the spring is supported by a hooking protrusion of the moving rod, and the other end of the spring is supported by the support structure.

15. the ring-shaped body includes an edge wall; 15. The relief valve of claim 14, wherein an edge wall of the ring-shaped body surrounds the mesh plate when the valve lid is in the closed position.

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