Battery Module

Abstract

The present invention discloses a battery module etc. having an improved structure to ensure safety from thermal events, etc. A battery module according to one aspect of the present invention may include a cell assembly including a plurality of stacked battery cells, a module case configured to house the cell assembly in an internal space and having a vent hole formed therein, and an inner cover member covering the side surface of the module case where the vent hole is formed from the inside, the inner cover member including an inner rupture part at a portion corresponding to the vent hole, and configured to allow vent gas ejected from the cell assembly to be discharged to the vent hole through the inner rupture part.

Description

[Technical Field]

[0001] The present invention relates to a battery, and more particularly to a battery module with enhanced safety, a battery pack including the same, and a vehicle.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0087933 filed on July 6, 2023, and Korean Patent Application No. 10-2024-0066698 filed on May 22, 2024, the entire contents of which are incorporated herein by reference in their entirety in their specifications and drawings. [Background technology]

[0003] Recently, as demand for portable electronic products such as smartphones, tablet PCs, and smartwatches has skyrocketed and electric vehicles have become more widespread, research into the batteries used in these products, particularly high-performance secondary batteries that can be repeatedly charged and discharged, has been actively conducted.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages of almost no memory effect compared to nickel-based secondary batteries, free charging and discharging, very low self-discharge rate, and high energy density.

[0005] Lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative electrode active materials, respectively, and include an electrode assembly in which a separator is sandwiched between positive and negative electrode plates coated with the positive and negative electrode active materials, and an exterior case, i.e., a battery case, that seals and houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries are classified into can-type secondary batteries, in which an electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which an electrode assembly is housed in an aluminum laminated sheet pouch, depending on the shape of the exterior material. Can-type secondary batteries can also be classified into cylindrical batteries and prismatic batteries depending on their shape. Currently, secondary batteries, especially lithium secondary batteries, are typically classified into three types: pouch-type, prismatic, and cylindrical.

[0007] Secondary batteries are widely used for driving or storing energy not only in small devices such as portable electronic devices but also in medium- to large-sized devices such as electric vehicles and energy storage systems (ESS).In addition, as the electric vehicle-related industry has grown significantly in recent years, interest in batteries, which can be considered a core technology, has been growing.

[0008] A plurality of such secondary batteries may be electrically connected and housed inside a module case to form a battery module, and a plurality of such battery modules may be connected to form a battery pack.

[0009] In a battery module using a conventional battery, for example, a pouch-type battery, if a thermal event such as thermal runaway occurs in one cell installed inside, thermal propagation may occur, in which the thermal event spreads to adjacent cells. Furthermore, if a battery pack includes multiple battery modules, thermal propagation may also occur between the battery modules. When thermal propagation occurs between cells and / or modules, high thermal energy may cause problems such as fire exposure, rupture, or explosion from the battery pack to the outside.

[0010] To prevent these problems, there is a need to develop a battery module or battery pack that can ensure high safety against heat propagation. In particular, to solve these problems, a conventional technique has been used in which a flame cover is attached to the outside of the battery module to prevent hot gas or fire from entering the outside. However, the structural connection between the flame cover attached to the outside of the module and the module is weak, which often results in the flame cover becoming detached. This conventional technique has the problem of making it difficult to reliably ensure the flame blocking effect of the battery module. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made to solve the above problems, and aims to provide a battery module having an improved structure to ensure safety from flames, gases, heat, sparks, etc. (hereinafter referred to as vent gas) generated inside or outside the battery module, a battery pack including the same, and a vehicle.

[0012] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0013] To achieve the above object, according to one aspect of the present invention, a battery module includes: a cell assembly having a plurality of stacked battery cells; a module case configured to house the cell assembly in an internal space and having a vent hole formed therein; and an inner cover member covering the side surface of the module case having the vent hole formed therein from the inside, the inner cover member having an inner rupture part at a portion corresponding to the vent hole, and configured to allow vent gas ejected from the cell assembly to be discharged to the vent hole through the inner rupture part.

[0014] Here, the vent hole may be formed in an upper portion of the module case, and the inner cover member may be located on an upper portion of the cell assembly.

[0015] The module case may also include a U-frame in which a base plate, a left plate, and a right plate are integrally formed, and an upper plate coupled to an upper end of the U-frame.

[0016] Also, the inner rupture portion may be configured in the form of a notch.

[0017] Also, a plurality of the inner rupture portions may be formed.

[0018] Additionally, at least some of the plurality of inner rupture portions may be configured to have different rupture conditions.

[0019] The inner rupture portion may be configured to have different rupture conditions depending on the position at a portion corresponding to the vent hole.

[0020] The cell assembly may also include a pouch-type cell as the battery cell, and the pouch-type cell may have an adhesive member partially attached to the sealing portion to maintain a folded structure of the sealing portion, and at least a portion of the portion to which the adhesive member is not attached may be located corresponding to the inner rupture portion.

[0021] The inner cover member may include a protrusion that protrudes toward the cell assembly.

[0022] The inner cover member may have the inner rupture portion positioned relatively outward.

[0023] The inner cover member may have a folded end, and the folded end may be interposed between the cell assembly and the module case.

[0024] The module case may further include an outer cover member covering the side surface on which the vent hole is formed from the outside of the module case, the outer cover member having an outer rupture portion at a portion corresponding to the vent hole.

[0025] Also, the outer rupture portion can be inserted into the vent hole.

[0026] A battery pack according to another aspect of the present invention for achieving the above object includes a battery module according to the present invention.

[0027] According to yet another aspect of the present invention, a vehicle for achieving the above object includes a battery module according to the present invention. [Effects of the Invention]

[0028] According to the present invention, the safety of a battery module or battery pack, or an apparatus including such a battery module or battery pack, such as an electric vehicle or ESS, is improved.

[0029] In particular, according to one aspect of the present invention, it is possible to prevent or delay the propagation of thermal runaway between battery cells or battery modules.

[0030] For example, when thermal runaway occurs in one battery cell in a battery module, vent gas (including heat, gas, flames, etc.) can be discharged through a vent hole located at the top of the battery module, which can prevent the vent gas from affecting adjacent cells or battery modules through convection, radiation, conduction, etc.

[0031] Therefore, according to this aspect of the present invention, it is possible to stably ensure the effect of blocking or suppressing thermal propagation between adjacent battery cells or adjacent battery modules.

[0032] Furthermore, according to one aspect of the present invention, in a situation where high-pressure vent gas is discharged from the battery cell due to thermal runaway, the cover member is stably positioned between the battery cell and the module case. As a result, the cover member protects the module case, preventing the problem of structural collapse of the module case due to fire or heat. Therefore, the propagation of thermal runaway in the battery cell or battery module due to such structural collapse can be more reliably prevented.

[0033] In addition, the present invention has various other effects, which will be described in each embodiment, or effects that can be easily inferred by those skilled in the art will not be described. [Brief explanation of the drawings]

[0034] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention, so the present invention should not be interpreted as being limited to the matters described in the drawings. [Figure 1] 1 is a schematic perspective view of a battery module according to an embodiment of the present invention; [Figure 2] 1 is an exploded perspective view of a partial configuration of a battery module according to an embodiment of the present invention; [Figure 3] 1 is a perspective view showing a partial configuration of a battery module according to an embodiment of the present invention; [Figure 4] FIG. 4 is an enlarged view of a portion A1 in FIG. 3. [Figure 5] 1 is a perspective view schematically illustrating the configuration of an inner cover member according to a different embodiment of the present invention; [Figure 6] 1 is a perspective view schematically illustrating the configuration of an inner cover member according to a different embodiment of the present invention; [Figure 7] FIG. 10 is an exploded perspective view schematically illustrating the configuration of an inner cover member and an upper plate according to another embodiment of the present invention. [Figure 8]10 is an enlarged perspective view of a portion where one vent hole is formed in a battery module according to another embodiment of the present invention; FIG. [Figure 9] 10 is an enlarged perspective view of a portion where one vent hole is formed in a battery module according to another embodiment of the present invention; FIG. [Figure 10] 10 is an enlarged perspective view illustrating a portion where one vent hole is formed in a battery module according to yet another embodiment of the present invention. FIG. [Figure 11] 11 is a diagram showing a cross-sectional configuration taken along line A3-A3' in FIG. [Figure 12] 12A to 12C are diagrams sequentially showing how the inner rupture part is deformed and ruptured by the pressure of the vent gas in the configuration of FIG. 11. [Figure 13] 12A to 12C are diagrams sequentially showing how the inner rupture part is deformed and ruptured by the pressure of the vent gas in the configuration of FIG. 11. [Figure 14] FIG. 13 is an enlarged view of a portion A6 in FIG. [Figure 15] 1 is a perspective view schematically illustrating a configuration of a battery cell included in a cell assembly according to an embodiment of the present invention; [Figure 16] FIG. 10 is a bottom perspective view of an inner cover member according to another embodiment of the present invention. [Figure 17] 17 is a partially enlarged cross-sectional view showing the inner cover member of FIG. 16 attached to the top of the cell assembly. FIG. [Figure 18] 10 is an enlarged cross-sectional view illustrating a partial configuration of a battery module according to still another embodiment of the present invention. [Figure 19] 10 is a cross-sectional view schematically illustrating a partial configuration of a battery module according to yet another embodiment of the present invention. [Figure 20] FIG. 10 is a perspective view schematically illustrating the configuration of a battery module according to yet another embodiment of the present invention. [Figure 21] FIG. 21 is an enlarged view of a portion A12 in FIG. 20. [Figure 22]FIG. 10 is an exploded perspective view schematically illustrating the configuration of a battery module according to yet another embodiment of the present invention. [Figure 23] 23 is an enlarged cross-sectional view of a portion where a vent hole is formed in the battery module of FIG. 22 in a combined state. FIG. [Figure 24] FIG. 10 is a diagram schematically illustrating a partial configuration of a battery module according to yet another embodiment of the present invention. [Figure 25] FIG. 10 is a diagram schematically illustrating a partial configuration of a battery module according to yet another embodiment of the present invention. [Figure 26] 4 is a partially enlarged view schematically illustrating deformation of an inner cover member and an outer cover member due to an increase in internal pressure in a battery module according to an embodiment of the present invention; [Figure 27] 1 is a perspective view schematically illustrating a configuration of a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0036] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0037] Although terms indicating directions such as up, down, left, right, front, and back are used in this specification, these terms indicate relative positions and are used only for convenience of explanation, and it will be obvious to those skilled in the art that these terms may change depending on the position, arrangement, rotation, and position of the object in question, the position of the observer, etc.

[0038] In addition, this specification includes several embodiments, and where the description of other embodiments is equally or similarly applicable, detailed description will be omitted and the description will focus on the differences between each embodiment.

[0039] FIG. 1 is a schematic perspective view of a battery module according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a partial configuration of the battery module according to an embodiment of the present invention.

[0040] 1 and 2, a battery module according to the present invention includes a cell assembly 100, a module case 200, and an inner cover member 300.

[0041] The cell assembly 100 may include one or more battery cells 110, particularly a plurality of battery cells 110. Here, each battery cell 110 may represent a single secondary battery or a battery group including a plurality of secondary batteries. In this specification, the battery cell 110 will be described as a single secondary battery.

[0042] Each battery cell 110, i.e., each secondary battery, may include an electrode assembly, an electrolyte, and a battery case. The battery case may have various shapes, and depending on the shape of the battery case, the battery cells 110 may be classified as pouch-type cells, cylindrical cells, prismatic cells, etc. The types, shapes, and structures of the battery cells 110 are well known as of the filing date of the present invention, and therefore will not be described in detail here. The present invention may be applied to various types of secondary batteries known as of the filing date of the present invention. The battery cell 110 may be a lithium secondary battery, but may of course be various other types of secondary batteries.

[0043] In the cell assembly 100, the plurality of battery cells 110 may be configured to be stacked in at least one direction. For example, the plurality of battery cells 110 may be stacked and arranged side by side in a horizontal direction, particularly in the left-right direction (X-axis direction), as shown in Fig. 2. The plurality of battery cells 110 included in the cell assembly 100 may be electrically connected to each other in series and / or parallel.

[0044] Meanwhile, in this specification, unless otherwise specified, the X-axis direction in which multiple battery cells 110 are stacked will be referred to as the left-right direction, the Y-axis direction, which is the horizontal direction perpendicular to the cell stacking direction, will be referred to as the front-rear direction, and the Z-axis direction, which is perpendicular to the XY plane, will be referred to as the up-down direction (vertical direction). Furthermore, in the case of a pouch-type cell, the Y-axis direction may also be referred to as the longitudinal direction of the cell. Furthermore, the left-right direction, front-rear direction, and up-down direction may be referred to as the first direction, second direction, and third direction, respectively.

[0045] Each battery cell 110 may include an electrode terminal 111. For example, as shown in FIG. 2 , each pouch-type cell included in the cell assembly 100 may include an electrode terminal 111 arranged to protrude in the front-to-rear direction. Such an electrode terminal 111 may be referred to as an electrode lead or an electrode tab. The multiple battery cells 110 may be electrically connected to each other in series or in parallel via such electrode terminals 111. The battery module may further include a bus bar 120 or the like for facilitating connection between the multiple electrode terminals 111 or for sensing electrical signals from the electrode terminals 111.

[0046] The module case 200 may have an internal space formed therein and may be configured to house a plurality of cell assemblies 100 in the internal space. For example, the module case 200 may include members for covering the upper, lower, left, right, front, and rear directions of the internal space. In particular, the members for covering each direction may be plate-shaped. The cell assemblies 100 may be positioned in the thus-defined internal space of the module case 200. The module case 200 may be at least partially made of metal and / or plastic. For example, certain portions of the module case 200 may be made of aluminum. Other portions of the module case 200 may be made of plastic.

[0047] The module case 200 may have a vent hole H1 formed therein, as indicated by H1 in Figures 1 and 2. The vent hole H1 may be formed on at least one surface of the module case 200 and may be configured to penetrate the module case 200 from the inside to the outside. As a result, the interior and exterior spaces of the module case 200 may be connected to each other through the vent hole H1. In particular, the vent hole H1 may serve as an outlet for discharging vent gases such as flames, gases, or sparks generated from the cell assemblies 100 inside the module case 200.

[0048] The inner cover member 300 may be positioned inside the module case 200. That is, the inner cover member 300 may be housed in the internal space of the module case 200 together with the cell assembly 100. Furthermore, the inner cover member 300 may be configured to cover the surface on which the vent hole H1 is formed. More specifically, the inner cover member 300 may be positioned in the portion of the space between the cell assembly 100 and the module case 200 on which the vent hole H1 is formed. That is, the inner cover member 300 may be disposed inside the surface of the module case 200 on which the vent hole H1 is formed.

[0049] The inner cover member 300 may include a fire-resistant material. For example, the inner cover member 300 may include or consist of mica, ceramic, inorganic materials, etc.

[0050] The inner cover member 300 may include an inner rupture portion 301. The inner rupture portion 301 may be provided at a portion corresponding to the vent hole H1. As shown in FIG. 1 , the inner cover member 300 may be configured so that the inner rupture portion 301 is located at the portion where the vent hole H1 is formed when the inner cover member 300 is attached to the inside of the module case 200. In this case, when the surface of the module case 200 is viewed from the outside of the module case 200, the inner rupture portion 301 may be exposed to the outside through the vent hole H1. When the battery module is in a normal state, the inner rupture portion 301 may be configured in a sealed form. As a result, even if the inner rupture portion 301 is exposed through the vent hole H1, the cell assembly 100 located inside the inner rupture portion 301 is not exposed to the outside through the vent hole H1.

[0051] The inner rupture portion 301 may be configured to rupture due to pressure or heat. In particular, it may emit vent gas when a thermal event, such as thermal runaway, occurs in one or more battery cells 110 included in the cell assembly 100. In this specification, vent gas may be a broad concept including not only gas emitted from a battery cell due to thermal runaway, but also gas generated by combustion, flames, sparks, active material particles, etc. The inner rupture portion 301 may be configured to rupture when a thermal event occurs in the cell assembly 100. In particular, the inner rupture portion 301 may be configured to rupture at least partially due to the pressure or heat of vent gas emitted from the cell assembly 100. When the inner rupture portion 301 ruptures, the vent gas emitted from the cell assembly 100 may be discharged to the vent hole H1 from the ruptured portion of the inner rupture portion 301. In this way, the inner cover member 300 closes the vent hole H1 of the module case 200 in a steady state, but can burst and open the vent hole H1 in the event of thermal runaway. Therefore, the vent gas emitted from the cell assembly 100 can be discharged to the outside of the module case 200 through the vent hole H1.

[0052] According to the above-described embodiment of the present invention, thermal propagation between battery modules can be suppressed by the inner cover member 300. For example, even if vent gas containing flames is discharged from a specific battery module, the other surrounding battery modules are provided with fire-resistant inner cover members 300, thereby suppressing damage to the cell assemblies 100 inside the other battery modules due to the heat of the vent gas.

[0053] Furthermore, according to the above embodiment of the present invention, in a steady state, the inner cover member 300 closes the vent hole H1, so that the cell assembly 100 is not exposed to the outside through the vent hole H1. This prevents foreign matter from outside the battery module from entering the cell assembly 100 through the vent hole H1.

[0054] Furthermore, according to the above-described embodiment of the present invention, the inner cover member 300 that protects the module case 200 from vent gas or heat is positioned inside the module case 200, thereby ensuring a stable bonding force between the inner cover member 300 and the module case 200.

[0055] In particular, even if vent gas discharged from other battery modules flows outside the module case 200, the inner cover member 300 is positioned inside the module case 200, which prevents the bonding strength between the inner cover member 300 and the module case 200 from being weakened by the vent gas from the outside. This prevents the inner cover member 300 from coming off the module case 200 and allows the position to be stably maintained.

[0056] This also ensures that the inner cover member 300 is prevented from coming off even in the event of a thermal event. For example, if vent gas is discharged outward from the vent hole H1 in a thermal runaway situation, the inner cover member 300 may be strongly pressurized outward by the vent gas. However, in the above-described configuration of the present invention, the module case 200 is positioned outside the inner cover member 300, so that the inner cover member 300 can continue to be supported inward without coming off outward.

[0057] Furthermore, the above-described embodiment of the present invention can effectively prevent structural collapse of the module case 200 in a thermal event. In particular, when thermal runaway occurs inside a battery module, vent gas and heat may concentrate at the portion of the module case 200 where the vent hole H1 is formed, potentially causing structural collapse of that portion. However, in the above-described embodiment of the present invention, the fire-resistant inner cover member 300 is positioned inside the portion of the module case 200 where the vent hole H1 is formed, thereby protecting the module case 200. As a result, even in a situation where vent gas is discharged through the vent hole H1, structural collapse of the surface of the module case 200 where the vent hole H1 is formed can be prevented. Therefore, according to this aspect of the present invention, it is possible to prevent thermal runaway propagation between battery cells 110 or between battery modules due to structural collapse of the module case 200.

[0058] 1 and 2, the vent hole H1 may be formed in the upper part of the module case 200. In this case, the inner cover member 300 may be located on the upper part of the cell assembly 100.

[0059] For example, if the module case 200 is formed in the shape of a substantially rectangular parallelepiped, six sides may be formed on the module case 200. In this case, the vent hole H1 may be formed on the top surface of the module case 200. The inner cover member 300 may be located above the cell assembly 100 and below the top surface of the module case 200.

[0060] In particular, the inner cover member 300 may be in a sheet shape and may be interposed between the cell assembly 100 and the module case 200. For example, when a plurality of battery cells 110 are stacked horizontally, the inner cover member 300 may be positioned on top of the cell assembly 100 in a horizontally laid form. In this case, it can be said that the inner cover member 300 is disposed parallel to the plane (XY plane) on which the plurality of battery cells 110 are stacked.

[0061] According to this embodiment, high-temperature vent gas can quickly move toward the upper vent hole H1 and be discharged to the outside. This facilitates the venting process of the battery module during thermal runaway. Furthermore, when the electrode terminals 111 of each battery cell 110 or the module terminals of the battery module are positioned in the front-to-rear direction in the cell assembly 100, the movement of vent gas toward the electrode terminals 111 or the module terminals can be suppressed. This prevents damage to the module bus bars, etc., provided on the module terminal side, caused by the vent gas.

[0062] Also, the module case 200 may include a U-frame 210 and an upper plate 220 as shown in FIG.

[0063] Here, the U frame 210 may be configured by integrating three unit plates provided in the module case 200. In particular, the U frame 210 may be configured by integrally forming a base plate 211, a left plate 212, and a right plate 213 in the module case 200. That is, the base plate 211, the left plate 212, and the right plate 213 of the U frame 210 may be manufactured as a single plate from the beginning and separated from each other by an additional process such as bending. For example, the U frame 210 may be configured by bending the left and right ends of a single plate laid horizontally upward. Such a U frame 210 may be open at the top, front, and rear.

[0064] The upper plate 220 may be coupled to the open upper end of the U-frame 210. Furthermore, both left and right ends of the upper plate 220 may be coupled to the upper ends of the left plate 212 and right plate 213 of the U-frame 210. In particular, in one embodiment of the present invention, a vent hole H1 may be formed in the upper plate 220. In this case, the inner cover member 300 may be located below the upper plate 220.

[0065] According to this embodiment of the present invention, the assembly of the battery module can be improved. In particular, according to this embodiment, the battery module assembly process can be performed in a manner that the cell assembly 100 is inserted into the internal space of the U frame 210 from the top of the U frame 210, the inner cover member 300 is mounted on the top of the cell assembly 100, and the upper plate 220 is mounted on the top of the inner cover member 300.

[0066] This assembly process facilitates the process of disposing the inner cover member 300 inside the module case 200. In particular, during the process of disposing the inner cover member 300 inside the module case 200, there is no need to consider too much about friction or tolerance between the inner surface of the module case 200 and the inner cover member 300. In addition, this assembly configuration also helps reduce the volume of the battery module by minimizing the space between the inner cover member 300 and the upper plate 220 by closely contacting them.

[0067] In the above embodiment, the modular case 200 may further include end frames 230, as shown in Fig. 2. The end frames 230 may be coupled to the front and rear open ends of the U frame 210 to close the front and rear of the interior space of the modular case 200.

[0068] In particular, the end frame 230 may be positioned in a direction in which the electrode terminals 111 of each battery cell 110 included in the cell assembly 100 are located. In this case, the end frame 230 may include an electrically insulating material, for example, a plastic material, to ensure insulation from the electrode terminals 111.

[0069] The components constituting the module case 200, for example, the U-frame 210, the upper plate 220, and the end frame 230, may be connected to each other by various methods such as welding, insertion, adhesive, hooks, etc. In particular, all or some of the components of the module case 200 may be made of aluminum or include such a material, which has excellent weldability, is advantageous for weight reduction, and ensures stable cooling performance.

[0070] 3 is a perspective view illustrating a partial configuration of a battery module according to an embodiment of the present invention, for example, in which the upper plate 220 is removed from the embodiment of FIG.

[0071] 3 , the inner cover member 300 may be configured to cover the upper end of the cell assembly 100. In particular, when the cell assembly 100 is configured to horizontally stack a plurality of battery cells 110, the inner cover member 300 may be configured to cover the upper ends of all of the battery cells 110 included in the cell assembly 100. Furthermore, the inner cover member 300 may be configured to have a shape and size that entirely covers the upper portion of the internal space defined by the U frame 210 and the end frames 230. For example, when the shape of the internal space defined by the U frame 210 and the end frames 230 is rectangular in top view, the inner cover member 300 may have a rectangular shape corresponding to this shape. Furthermore, the inner cover member 300 may be configured to have the same or similar shape, size, area, etc. as the upper plate 220.

[0072] According to this embodiment of the present invention, the cell assemblies 100 or the upper plate 220 can be more reliably protected overall from external factors of the battery module at the location of the inner cover member 300. For example, when vent gas discharged from another battery module flows above the outside of the battery module, the vent gas can be more reliably protected from affecting the cell assemblies 100 inside the battery module. In particular, problems such as thermal damage or thermal runaway propagation of the internal cell assemblies 100 due to the heat of the external vent gas can be more reliably prevented. In addition, this can more reliably protect the cell assemblies 100 inside the battery from foreign objects such as dust or conductors outside the battery module. Furthermore, this can protect the inner surface of the upper plate 220 from vent gas or heat generated inside the module case 200.

[0073] The inner rupture portion 301 may remain closed when the battery module is in a normal state. In this case, it is possible to prevent external vent gas or foreign matter from entering the normal battery module through the vent hole H1. Furthermore, if an abnormal condition such as thermal runaway occurs inside the battery module, the inner rupture portion 301 may rupture to discharge the internal vent gas to the outside. That is, the inner rupture portion 301 may be transformed from a closed state to an open state by heat or vent gas. In this case, the inner rupture portion 301 may rupture in various ways to penetrate inward and outward directions relative to the inner cover member 300.

[0074] In particular, the inner rupture portion 301 may be configured in the form of a notch, which will be described in more detail with further reference to FIG.

[0075] FIG. 4 is an enlarged view of a portion A1 in FIG.

[0076] 3 and 4, an inner rupture portion 301 may be formed on at least one surface of the inner cover member 300. In particular, the inner rupture portion 301 may be in the form of a notch recessed inward from the surface of the inner cover member 300, as indicated by N in Fig. 4. For example, when the inner cover member 300 is formed in a sheet shape, the notch-shaped inner rupture portion 301 may be provided by partially thinning the thickness of the inner cover member 300.

[0077] The notches N of the inner rupture portion 301 may be formed in a lattice pattern. That is, the recessed notches N may be elongated to form a plurality of notch lines, and the inner rupture portion 301 may be configured so that the plurality of notch lines intersect with each other. For example, the inner rupture portion 301 may be configured so that one or more notch lines extending in the left-right direction and one or more notch lines extending in the front-rear direction are perpendicular to each other.

[0078] This embodiment allows the inner rupture portion 301 to rupture quickly in situations such as thermal runaway. In particular, in this embodiment, the vent hole H1 is stably covered by the inner rupture portion 301 in a steady state, and the inner rupture portion 301 ruptures quickly due to the pressure of the vent gas. Furthermore, in this embodiment, when the internal pressure increases, the notch N makes it easier for the inner cover member 300 to deform. This makes it easier for the inner rupture portion 301 to rupture due to the increased pressure resistance.

[0079] Furthermore, according to the above embodiment, the process of providing the notch N can be more easily performed. According to the above embodiment, the process of providing the inner rupture portion 301 with a shape or size corresponding to the vent hole H1 can be easily performed.

[0080] The notch N for forming the inner rupture portion 301 may be provided on the upper surface of the inner cover member 300. For example, as shown in FIG. 4, the inner rupture portion 301 may be recessed downward from the upper surface of the inner cover member 300. In this case, the notch N can be said to be located on the side of the inner cover member 300 facing the vent hole H1. As a result, the notch can be exposed to the outside of the module case 200 through the vent hole H1.

[0081] According to this embodiment of the present invention, when vent gas is emitted from the cell assemblies 100 inside the module case 200, the internal pressure of the vent gas can quickly rupture the internal rupture portion 301 of the inner cover member 300. In an embodiment in which the cell assemblies 100 are located below the inner cover member 300, when the internal pressure increases due to the vent gas, the inner cover member 300 can be pressurized upward from below. In this case, the notches N formed on the upper surface of the inner cover member 300 allow the internal rupture portion 301 to be quickly and smoothly broken by the pressure. Meanwhile, when vent gas is discharged from another battery module and flows back into the vent hole H1, the inner cover member 300 can be pressurized downward from above. In this case, the notches N are not formed on the lower surface of the inner cover member 300, making it less likely to be broken by the downward pressure. That is, according to the above embodiment, the inner rupturable portion 301 is configured to easily rupture due to pressure inside (below) the inner cover member 300, but is not easily ruptured due to pressure outside (upper) the inner cover member 300.

[0082] A plurality of inner rupture portions 301 may be formed on the inner cover member 300. For example, as shown in Figures 2 and 3, a plurality of inner rupture portions 301 spaced apart from each other in the horizontal direction may be provided on the surface of the sheet-like inner cover member 300. Each inner rupture portion 301 may consist of a plurality of notch lines.

[0083] Furthermore, a plurality of vent holes H1 may be formed in one module case 200. The inner rupture portions 301 may be formed to correspond to each vent hole H1. For example, the inner rupture portions 301 may be provided to correspond one-to-one with the vent holes H1.

[0084] According to this embodiment, even if vent gas is emitted from any part of the cell assembly 100, the vent gas can be quickly discharged to the outside through the adjacent inner rupture portion 301 and vent hole H1.

[0085] In particular, the inner cover member 300 may be configured such that at least one inner rupture portion 301 faces all of the battery cells 110 included in the cell assembly 100. For example, referring to the configuration shown in FIG. 2 , the cell assembly 100 may include a plurality of battery cells 110 stacked in the left-right direction (X-axis direction). A plurality of vent holes H1 may also be arranged in the stacking direction (left-right direction) of the battery cells 110. In this case, the inner rupture portions 301 may be arranged directly above all of the battery cells 110. As a result, even if vent gas is generated in any of the battery cells 110, the vent gas may rupture the inner rupture portion 301 located directly above it, and be smoothly discharged to the vent hole H1. In this embodiment, one inner rupture portion 301 may be arranged corresponding to one or more battery cells 110.

[0086] In addition, the inner cover member 300 may be configured so that two or more inner rupture portions 301 are arranged corresponding to one battery cell 110. For example, referring to the embodiment of Fig. 2, each battery cell 110 may be arranged long in the front-rear direction so that the electrode terminal 111 is located at the end in the front-rear direction (Y-axis direction). In this case, two or more inner rupture portions 301 may also be arranged in the front-rear direction.

[0087] It is difficult to accurately predict where vent gas will be generated from one battery cell 110. Therefore, as in the above embodiment, two or more inner rupture parts 301 are disposed corresponding to one battery cell 110, so that no matter where vent gas is emitted from in the battery cell 110, the vent gas can be quickly discharged from the nearest inner rupture part 301.

[0088] In embodiments in which the inner cover member 300 includes multiple inner rupture portions 301, at least some of the rupture portions may be configured to have different rupture conditions, as will be more particularly described with reference to Figures 5 and 6.

[0089] 5 and 6 are perspective views schematically illustrating the configuration of an inner cover member 300 according to different embodiments of the present invention.

[0090] 5 and 6, in an embodiment in which a single inner cover member 300 has a plurality of inner rupture portions 301, the two or more inner rupture portions 301 may be configured to have different rupture conditions. That is, when a plurality of inner rupture portions 301 are provided in the horizontal direction, at least some of them may rupture under different conditions.

[0091] Here, the rupture condition of the inner rupturable portion 301 may be set in consideration of factors that cause the inner rupturable portion 301 to rupture. For example, if the inner rupturable portion 301 ruptures due to pressure, the rupture condition may be set based on the magnitude of the pressure. That is, two or more inner rupturable portions 301 may be configured to have different rupture pressure conditions. In this case, the two or more inner rupturable portions 301 may rupture due to different magnitudes of pressure.

[0092] The configuration of two or more inner rupture portions 301 with different rupture conditions can be implemented in various ways. For example, when the inner rupture portion 301 has a plurality of notch lines, the rupture conditions of the inner rupture portion 301 can be configured differently by forming the notch lines with different intervals and / or different numbers, as shown in Figures 5 and 6. In this case, the inner rupture portion 301 with a relatively narrow interval between the notch lines and a large number of notch lines formed thereon may have a lower rupture pressure than the other inner rupture portions 301.

[0093] In another example, when the inner rupture portion 301 is implemented as a notch, the notch depths of two or more inner rupture portions 301 may be different. In this case, the inner rupture portion 301 having a relatively deeper notch depth may have a lower burst pressure than the other inner rupture portions 301.

[0094] In another example, the inner rupture portions 301 may have different notch widths (horizontal lengths) to vary the rupture conditions. In this case, the inner rupture portions 301 with relatively larger notch widths have a lower burst pressure than the other inner rupture portions 301.

[0095] In particular, the two or more inner rupture portions 301 may be configured to have different rupture conditions depending on the longitudinal direction of the battery cells 110 and / or the stacking direction of the battery cells 110. For example, the inner cover member 300 shown in Figures 5 and 6 may be a modified version of the inner cover member 300 shown in Figures 2 and 3. In Figures 5 and 6 as well, the X-axis direction may be the stacking direction of the battery cells 110, and the Y-axis direction may be the longitudinal direction of the battery cells 110.

[0096] 5, a plurality of inner rupture portions 301 such as RY1, RY2, and RY3 may be spaced apart in the front-rear direction (Y-axis direction), which is the longitudinal direction of the battery cell 110. In this case, the inner rupture portions 301 arranged in the front-rear direction may be configured to rupture under different conditions. For example, the inner rupture portion 301 designated by RY1, the inner rupture portion 301 designated by RY2, and the inner rupture portion 301 designated by RY3 may each have a notch formed therein so as to rupture under different pressure conditions.

[0097] Furthermore, the rupture condition of the inner rupture portion 301 located relatively closer to the outer periphery in the longitudinal direction of the battery cell 110 may be set higher than that of the inner rupture portion 301 located relatively closer to the center. For example, in the embodiment of FIG. 5 , RY1 may be the inner rupture portion 301 located relatively closer to the outer periphery than RY2. In this case, the inner rupture portion 301 designated by RY1 may be configured to rupture under a higher pressure condition than the inner rupture portion 301 designated by RY2. For this reason, the spacing between the notch lines of RY1 may be wider than the spacing between the notch lines of RY2. The number of notch lines of RY1 may be smaller than the number of notch lines of RY2. Furthermore, since the inner rupture portion 301 designated by RY2 is located relatively closer to the outer periphery than the inner rupture portion 301 designated by RY3, the rupture condition of RY2 may be set higher than the rupture condition of RY3. In this case, the distance between the notch lines of RY2 may be wider than the distance between the notch lines of RY3, and the number of notch lines of RY2 may be smaller than the number of notch lines of RY3.

[0098] In this embodiment, when a thermal runaway situation occurs in the cell assembly 100, the inner rupture portion 301 located toward the center in the longitudinal direction of the battery cell 110 may rupture relatively first. As a result, in the early stage of thermal runaway when the amount of vent gas discharged is not large, the vent gas is likely to be discharged from the center in the longitudinal direction of the battery cell 110 rather than from the outer periphery. Therefore, this embodiment of the present invention improves the effect of suppressing the propagation of thermal runaway between battery modules. In other words, although other battery modules are likely to be disposed adjacent to the outer periphery in the longitudinal direction of the battery cell 110, this embodiment allows the vent gas to be discharged first at a position as far away as possible from the other battery modules.

[0099] In particular, the electrode terminal 111 of the battery cell 110 and a module terminal electrically connected to the electrode terminal 111 are likely to be disposed at the end of the battery cell 110 in the longitudinal direction. In addition, the module terminal of another battery module is often disposed adjacent to the location of such a module terminal via a bus bar between the modules. Therefore, when vent gas is first discharged from the center of the battery cell 110 in the longitudinal direction, as in the above embodiment, it is possible to more reliably prevent thermal runaway from spreading to other adjacent battery modules due to the high heat of the discharged vent gas.

[0100] 6, as shown by RX1 and RX2, a plurality of inner rupture portions 301 may be spaced apart in the left-right direction (X-axis direction), which is the stacking direction of the battery cells 110. In this case, the inner rupture portions 301 arranged in the left-right direction may be configured to rupture under different conditions. For example, the inner rupture portion 301 shown by RX1 and the inner rupture portion 301 shown by RX2 may each have a notch formed therein so as to rupture under different pressure conditions.

[0101] Furthermore, the inner rupture portion 301 located relatively closer to the center in the stacking direction of the battery cells 110 may be set to have a lower rupture condition than the inner rupture portion 301 located relatively closer to the outer periphery. For example, in the embodiment of FIG. 6, RX2 may be the inner rupture portion 301 located relatively closer to the center than RX1. In this case, the inner rupture portion 301 on the center side indicated by RX2 may be configured to rupture under a lower pressure condition than the inner rupture portion 301 on the outer periphery side indicated by RX1. For this purpose, the spacing between the notch lines of RX2 and the number of notch lines may be narrower and more numerous than those of RX1.

[0102] In this embodiment, when thermal runaway occurs in the cell assembly 100, the inner rupture portion 301 located at the center in the stacking direction of the battery cells 110 may rupture relatively first, thereby more effectively suppressing the propagation of thermal runaway to other battery modules arranged outside the battery module in the stacking direction of the battery cells 110.

[0103] Meanwhile, in the embodiment of Figures 5 and 6, an embodiment has been described in which the rupture conditions of the inner rupture portion 301 are formed differently depending on the spacing and number of notch lines. However, as mentioned above, the configuration in which the rupture conditions are formed differently can be embodied in various other ways, such as by changing the depth or width of the notch.

[0104] In another example, an inner rupture portion 301 located relatively closer to the outer periphery in the longitudinal direction or stacking direction of the battery cells 110 may be set to a lower rupture condition than an inner rupture portion 301 located relatively closer to the center. For example, in the embodiment of FIG. 6 , the inner rupture portion 301 located relatively closer to the outer periphery in the stacking direction of the battery cells 110 indicated by RX1 may have a lower rupture condition, such as a narrower distance between notch lines, a deeper notch, or a wider notch, than the other inner rupture portions 301 indicated by RX2.

[0105] In particular, when the internal pressure of the battery module increases, the center portion of the module case 200, for example, the center portion of the upper plate 220, may expand the most depending on the shape or material of the module case 200. In this case, the center portion of the inner cover member 300 located inside the upper plate 220 also receives the highest pressure, and the inner rupture part 301 located at the center is likely to rupture first, regardless of the location where thermal runaway occurs in the cell assembly 100.

[0106] For such a battery module, by setting the rupture condition of the inner rupture part 301 located on the outer shell side low as in the above embodiment, even if vent gas is emitted from the outermost shell side of the cell assembly 100, the vent gas may be more likely to be immediately discharged by the inner rupture part 301 located on the outer shell side. As a result, according to the embodiment of the present invention, the vent gas is not concentrated and discharged at a specific part (center part), and the vent gas can be discharged to the outside as quickly as possible from the position where thermal runaway occurs.

[0107] Furthermore, in an embodiment in which the inner cover member 300 includes multiple inner rupture portions 301, at least some of the rupture portions may be configured to have different rupture sizes, as will be described in more detail with further reference to FIG.

[0108] FIG. 7 is an exploded perspective view schematically illustrating the configuration of an inner cover member 300 and an upper plate 220 according to another embodiment of the present invention.

[0109] 7, when multiple inner rupture portions 301 are formed in one inner cover member 300, the two or more inner rupture portions 301 may be configured to have different rupture sizes, i.e., different sizes of the portions opened when ruptured. For example, the two or more inner rupture portions 301 may be configured to have different sizes in the horizontal direction (X-axis or Y-axis direction).

[0110] Furthermore, the inner rupture portion 301 located relatively closer to the center may be configured to have a larger rupture size than the inner rupture portion 301 located relatively closer to the outer periphery. For example, in the embodiment of FIG. 7 , a plurality of inner rupture portions 301 may be arranged in the front-rear direction, i.e., the longitudinal direction of the battery cell 110, as indicated by RY1′, RY2′, and RY3′. In this case, the inner rupture portion 301 located relatively closer to the center may be formed larger than the inner rupture portion 301 located relatively closer to the outer periphery. As a more specific example, RY2′ located relatively closer to the center may be formed with a larger notch area than RY1′. In addition, RY3′ located relatively closer to the center may be formed with a larger notch area than RY2′. In this case, the notch area can be increased by increasing the length of the notch line or the number of notch lines.

[0111] According to this embodiment, when the inner rupture portions 301 rupture, they may be formed to discharge different amounts of vent gas. In particular, when the rupture size of the inner rupture portions 301 located in the center is increased as in the embodiment of Fig. 7, a larger amount of vent gas may be discharged from the center of the upper plate 220 than from the outer periphery. This reduces the impact of the vent gas on other battery modules adjacent in the horizontal direction.

[0112] In an embodiment in which the plurality of inner rupture portions 301 are formed to have different rupture sizes, the vent holes H1 may also be formed to have different sizes. For example, as shown in Fig. 7, a plurality of vent holes H1 may be formed in the upper plate 220 disposed on the outer side (upper side) of the inner cover member 300 to correspond to the plurality of inner rupture portions 301, respectively. In this case, the plurality of vent holes H1 may have different sizes corresponding to the rupture sizes of the corresponding inner rupture portions 301.

[0113] As a more specific example, in the embodiment of FIG. 7, for each of RY1', RY2' and RY3' which are a plurality of inner rupture portions 301 arranged in the longitudinal direction of the battery cell 110, the corresponding vent holes H1 can be H1Y1', H1Y2' and H1Y3'. At this time, if the rupture sizes of RY1', RY2' and RY3' have the relationship of RY1' < RY2' < RY3', the sizes of the holes of H1Y1', H1Y2' and H1Y3' can be formed so as to have the relationship of H1Y1' < H1Y2' < H1Y3'. In this case, it can be said that the size of the vent hole H1 formed on the central side is relatively larger than the size of the vent hole H1 formed on the outer side.

[0114] According to such an implementation configuration of the present invention, since the plurality of vent holes H1 have different opening areas corresponding to the rupture sizes of the corresponding inner rupture portions 301, the technical effects due to the differences in the rupture sizes of the inner rupture portions 301 are stably ensured. Also, in this case, by preventing the vent hole H1 from being formed unnecessarily large, it is possible to suppress the inflow of vent gas, foreign matter, etc. from the outside of the battery module into the vent hole H1.

[0115] On the other hand, in the embodiment of FIG. 7, the description was centered on the configuration in which the inner rupture portions 301 arranged in the front-rear direction (Y-axis direction) of the battery module are formed to have different rupture sizes, but the inner rupture portions 301 arranged in the left-right direction (X-axis direction) of the battery module can also be formed to have different rupture sizes. A detailed description thereof will be omitted.

[0116] The inner rupture portion 301 can be configured to have different rupture conditions for each position. This will be specifically described with reference to FIGS. 8 and 9.

[0117] FIGS. 8 and 9 are perspective views showing an enlarged view of a portion where one vent hole H1 is formed in a battery module according to different embodiments of the present invention. For example, FIGS. 8 and 9 can be an embodiment in which the A2 portion of FIG. 1 is enlarged.

[0118] 8 and 9, one inner rupture part 301 may be provided at a position corresponding to one vent hole H1. In this case, the inner rupture part 301 may be configured to have different rupture conditions at different positions in the portion corresponding to the vent hole H1. That is, one inner rupture part 301 may be designed to have different rupture conditions at different positions.

[0119] 8, one inner rupture portion 301 may have a plurality of notch lines NY1, NY2, and NY3 arranged in the left-right direction in the portion exposed to the vent hole H1. In this case, the two or more notch lines may have different rupture conditions, for example, different rupture pressure conditions.

[0120] In this case, the rupture condition may be set differently depending on the depth or width of the notch. For example, at least two of the three notch lines NY1, NY2, and NY3 in FIG. 8 may be configured to have different notch depths.

[0121] Furthermore, the inner rupture portion 301 may be configured so that the central portion of the vent hole H1 has a relatively low rupture condition. For example, in the embodiment of Figure 8, NY2 may be a notch line located more centrally than NY1 or NY3. In this case, the depth or width of the notch line of NY2 may be formed deeper or wider than the depth or width of the notch lines of NY1 and NY3.

[0122] According to this embodiment, the central portion of the vent hole H1 can be more easily ruptured in one inner rupturable portion 301. As a result, the ruptured portion of the inner rupturable portion 301 is located toward the center of the vent hole H1, ensuring a stable and wide communication area between the inner rupturable portion 301 and the vent hole H1. In this case, vent gas can be more smoothly discharged from the inner rupturable portion 301 and the vent hole H1.

[0123] 9, one inner rupture portion 301 may have a plurality of notch lines NX1, NX2, and NX3 arranged in the front-rear direction in the portion exposed to the vent hole H1, and at least two of the plurality of notch lines NX1, NX2, and NX3 may be configured with different rupture conditions.

[0124] 9, the inner rupture portion 301 may be configured so that the central portion of the vent hole H1 has a relatively low rupture condition. For example, NX2 is a notch line located closer to the center than NX1 and may be formed to be deeper or wider than NX1. Also, NX3 is a notch line located closer to the center than NX2 and may be formed to be deeper or wider than NX2.

[0125] In particular, in the embodiment shown in Fig. 9, the vent hole H1 is formed larger in the Y-axis direction than in the X-axis direction, so the longitudinal direction of the vent hole H1 can be said to be the Y-axis direction. In this case, more notch lines can be formed along the longitudinal direction of the vent hole H1. That is, as shown in Fig. 9, the number of notch lines exposed in the vent hole H1 can be more along the Y-axis direction, which is the longitudinal direction of the vent hole H1, than along the X-axis direction.

[0126] In this case, it is possible to more easily and accurately realize a configuration in which the rupture conditions are different for multiple notch lines arranged along the longitudinal direction of the vent hole H1. In this configuration, a sufficient distance can be secured between the notch line located toward the center of the vent hole H1 and the notch line located toward the outer edge of the vent hole H1. This makes it easy to realize a configuration in which the portion corresponding to the center of the vent hole H1 ruptures more easily for one inner rupturable portion 301. This makes it easier for the ruptured portion of the inner rupturable portion 301 to communicate with the vent hole H1.

[0127] Figure 10 is an enlarged perspective view of a portion of a battery module according to yet another embodiment of the present invention, where one vent hole H1 is formed. For example, Figure 10 can be considered another modification of Figure 8 or Figure 9. Figure 11 is a cross-sectional view taken along line A3-A3' in Figure 10. In the embodiment shown in Figure 11, the inner cover member 300 and the upper plate 220 are spaced apart from each other in the vertical direction (Z-axis direction), but this is for convenience of illustration and they may also be in close contact with each other.

[0128] 10 and 11, the inner rupture portion 301 may have a peripheral notch line, as indicated by NC. The peripheral notch line NC may be ring-shaped corresponding to the outer periphery of the vent hole H1. For example, if the vent hole H1 is formed in a substantially elliptical shape, the peripheral notch line NC may be formed in an elliptical ring shape along the periphery of the vent hole H1. Furthermore, if the inner cover member 300 is positioned below the upper plate 220, the peripheral notch line NC of the inner rupture portion 301 may be located directly below or slightly inside the periphery of the vent hole H1. For example, as in the embodiment of FIG. 11, the peripheral notch line NC may be located inside the vent hole H1 in the horizontal direction (Y-axis direction). In this case, the peripheral notch line NC of the inner rupture portion 301 may be formed to be slightly smaller than the vent hole H1.

[0129] According to this embodiment, it is possible to more easily realize a configuration in which the inner rupture portion 301 ruptures along the outer circumferential notch line NC, which will be described in detail with reference to the configurations of FIGS.

[0130] 12 and 13 are diagrams sequentially showing how the inner rupturable portion 301 in the configuration of FIG. 11 is deformed and ruptured by the pressure of the vent gas.

[0131] First, referring to FIG. 12 , if thermal runaway occurs in the cell assembly 100, vent gas may pressurize the inner cover member 300, as indicated by arrow A4. In this case, the inner cover member 300 may be deformed such that the inner rupture portion 301 expands upward from the vent hole H1. In particular, the outer peripheral notch line NC of the inner rupture portion 301 is located directly below the vent hole H1 or horizontally inward from the periphery of the vent hole H1, so that the entire inner portion of the outer peripheral notch line NC in the horizontal direction can be exposed upward through the vent hole H1. More specifically, the embodiments of FIGS. 11 and 12 show two outer peripheral notch lines NC, and the two outer peripheral notch lines NC can be said to be located horizontally inward from the vent hole H1.

[0132] In this case, if the upward deformation of the inner cover member 300 exceeds a certain level, the circumferential notch lines NC may rupture. In this case, as shown in FIG. 13 , the inner rupture portion 301 located inside the two circumferential notch lines NC may separate from the inner cover member 300 and be separated and released to the outside through the vent hole H1 as indicated by arrow A5. As a result, the rupture of the inner rupture portion 301 opens the space between the two circumferential notch lines NC and allows communication with the vent hole H1. In this embodiment, the inner rupture portion 301 formed between the two circumferential notch lines NC is easily discharged to the outside of the vent hole H1, quickly and smoothly achieving communication between the ruptured portion of the inner rupture portion 301 and the vent hole H1.

[0133] Meanwhile, although FIG. 13 shows a configuration in which the inner rupture portion 301 is entirely separated from the inner cover member 300, the inner rupture portion 301 may be embodied so that only a portion of the inner rupture portion 301 is separated from the inner cover member 300.

[0134] In addition, the inner rupture portion 301 may have, in addition to the circumferential notch line NC, straight notch lines extending in one direction, as indicated by NX and NY in FIGS. 10 and 11. Here, the straight notch lines may extend in the left-right direction (X-axis direction) as indicated by NX, or in the front-back direction (Y-axis direction) as indicated by NY. Furthermore, the straight notch lines may include two or more types of notch lines extending in different directions that intersect with each other. In such an embodiment, at least a portion of the straight notch lines NX and NY may be located inside the circumferential notch line NC. For example, referring to the embodiment of FIG. 11, multiple straight notch lines NX may be located between two circumferential notch lines NC in the horizontal direction.

[0135] This embodiment makes it easier to rupture the inner rupture portion 301. For example, as shown by arrow A4 in FIG. 12 , when vent gas pressure is applied from the inside and the inner rupture portion 301 is deformed, the straight notch lines NX can make it easier for the inner rupture portion 301 to deform. In particular, the straight notch lines NX can be formed on the upper surface of the inner cover member 300. In this case, the inner rupture portion 301 can be warped upward more easily. This can increase the magnitude or speed of the force, e.g., tensile force, applied to the two outer circumferential notch lines NC. As a result, the portions along the outer circumferential notch lines NC rupture more quickly, facilitating the rupture of the inner rupture portion 301 and the subsequent release of vent gas.

[0136] Furthermore, the circumferential notch line NC and the notch lines NX and NY disposed therein may be formed in opposite notching directions. In particular, the circumferential notch line NC may be formed on the inner surface of the inner cover member 300 facing the cell assembly 100, and the linear notch lines NX and NY may be formed on the outer surface of the inner cover member 300 facing the module case 200. For example, as shown in FIG. 11 , the linear notch lines NX and NY may be formed recessed downward from the upper surface of the inner cover member 300, and the circumferential notch line NC may be formed recessed upward from the lower surface of the inner cover member 300. In FIG. 10 , the upper surface of the inner cover member 300 is exposed through the vent hole H1, so the circumferential notch line NC formed on the lower surface of the inner cover member 300 is shown with a dotted line. However, the circumferential notch line NC may be formed in a continuous, elongated ring shape, such as an ellipse. Of course, the circumferential notch line NC may be formed in an overall ring shape, or may be formed discontinuously. Furthermore, in this case, the outer circumferential notch line NC may be formed so as to penetrate the inner cover member 300.

[0137] This embodiment can further improve the rupture performance of the inner rupture portion 301. This will be described in detail with reference to FIG.

[0138] FIG. 14 is an enlarged view of the A6 portion of FIG.

[0139] 12 and 14, when the inner rupture portion 301 is pressurized by vent gas, the outer circumferential notch line NC is adjacent to the periphery of the vent hole H1 and may be the location where deformation begins in the inner cover member 300. At this time, the outer circumferential notch line NC may receive a force that warps it approximately counterclockwise as indicated by arrow A7. Meanwhile, the linear notch line NX, located in the portion warping upward from the inner cover member 300, may receive a force that warps it approximately clockwise as indicated by arrow A8. That is, in one inner rupture portion 301, the outer circumferential notch line NC and the linear notch line NX may receive forces that warp in different directions, in other words, in opposite rotational directions.

[0140] 11 to 14, the circumferential notch lines NC and the linear notch lines NX may be formed on opposite surfaces. In particular, the circumferential notch lines NC and the linear notch lines NX may be formed on the inner surface and the outer surface of the inner cover member 300, respectively, taking into consideration the rotational direction of the tensile force applied to the part when pressurized by the vent gas.

[0141] According to this embodiment, the rupture of the inner rupture portion 301 occurs more quickly. In addition, in this case, the rupture shape of the inner rupture portion 301 can be more easily controlled.

[0142] Meanwhile, when the inner rupture portion 301 has both the circumferential notch line NC and the linear notch lines NX and NY as in the above embodiment, the circumferential notch line NC may be set to a lower rupture condition than the linear notch lines NX and NY.

[0143] 12, when vent gas pressure acts on the inner rupture portion 301 side, the inner rupture portion 301 may be configured so that the circumferential notch line NC ruptures before the linear notch lines NX and NY when the pressure reaches a certain level or above. To achieve this, the circumferential notch line NC may be configured to be deeper or wider than the linear notch lines NX and NY.

[0144] According to this embodiment, as shown in Fig. 13, the inner rupture portion 301 can be completely separated from the inner cover member 300 along the outer circumferential notch line NC. This allows the inner rupture portion 301 to be ruptured in a neater shape, ensuring a wider rupture area. In particular, when the outer circumferential notch line NC is aligned with the size and shape of the vent hole H1, the communication area between the outer circumferential notch line NC and the vent hole H1 can be maximized. This is advantageous in improving the discharge performance of vent gas passing through the inner rupture portion 301.

[0145] 2, the cell assembly 100 may include a pouch-type cell as the battery cell 110. This will be described in detail with reference to FIG.

[0146] FIG. 15 is a perspective view schematically illustrating a configuration of a battery cell 110 included in a cell assembly 100 according to an embodiment of the present invention.

[0147] Referring to FIG. 15, a pouch-type cell may be a pouch-type battery, with the battery case being made of a pouch exterior material. The pouch-type battery may also include a storage section R and a sealing section S. Here, the storage section R is a section that stores an electrode assembly, an electrolyte, etc., inside. The sealing section S may be provided on the periphery of the storage section R and may be a section to which the pouch exterior material is welded. The storage section R of the pouch-type battery is formed in a substantially rectangular shape, and a battery with the sealing sections S formed on all four sides (edges) of the storage section R may be called a four-sided sealed cell, and a battery with the sealing sections S formed on all three sides (edges) of the storage section R may be called a three-sided sealed cell. While FIG. 14 shows a three-sided sealed cell, the present invention is not limited to a particular form of pouch-type battery.

[0148] At least a portion of the sealing portion S of such a pouch-type cell may be folded to secure space, improve sealing performance, etc. For example, in the embodiment of FIG. 15 , the upper sealing portion S of the pouch-type cell, where the electrode terminals 111 are not located, may be folded toward the storage portion R. In this case, an adhesive member may be attached to the pouch-type cell as shown by B, so that the folded structure of the sealing portion S is maintained. In particular, the adhesive member B may be in the form of a tape.

[0149] Furthermore, the adhesive member B may be partially attached to the sealing portion S. In particular, a plurality of adhesive members B may be attached to one sealing portion, spaced apart from each other in the longitudinal direction of the battery cell 110. For example, in the embodiment of FIG. 15 , a plurality of adhesive members B may be attached to the top sealing portion of the pouch-type cell, spaced apart from each other in the Y-axis direction, which is the longitudinal direction of the pouch-type cell. In this case, there may be a portion of the top sealing portion of the pouch-type cell to which the adhesive member B is not attached, such as the portion indicated by A9.

[0150] In this embodiment, an inner cover member 300 may be disposed on the outer side of the upper end sealing portion S of the pouch-type cell, facing the upper end sealing portion S. For example, referring to Fig. 2, the cell assembly 100 may be configured such that a plurality of pouch-type cells are stacked horizontally in a vertically upright state. Then, the inner cover member 300 may be disposed on the top of the cell assembly 100.

[0151] In this case, at least a portion of the upper sealing portion S of the battery cell 110 included in the cell assembly 100, where the adhesive member B is not attached, may be located corresponding to the inner rupture portion 301. That is, the inner rupture portion 301 of the inner cover member 300 may be disposed at least partially opposite the unbonded portion A9 of the sealing portion S of the battery cell 110. As a more specific example, when the inner cover member 300 is located on the top of the cell assembly 100, at least a portion of the unbonded portion A9 may be configured to overlap the inner rupture portion 301 in the horizontal direction. In this case, the unbonded portion A9 may be located below the inner rupture portion 301 in the vertical direction (Z-axis direction). In particular, the inner cover member 300 may be provided with a plurality of inner rupture portions 301, and all of the inner rupture portions 301 may at least partially overlap the unbonded portion A9 of the battery cell 110.

[0152] According to this embodiment of the present invention, when vent gas is emitted from the battery cell 110, the vent gas may move in a vertical direction (Z-axis direction) toward the inner rupture portion 301. In particular, in a thermal runaway situation of the battery cell 110, the vent gas is likely to be emitted first from the unbonded portion A9. In this embodiment, since the inner rupture portion 301 is located in the direction in which the unbonded portion A9 is emitted, the pressure of the vent gas to the inner rupture portion 301 may be maximized. Therefore, the rupture of the inner rupture portion 301 may occur more quickly. Furthermore, after the rupture of the inner rupture portion 301, the vent gas may be discharged from the inner rupture portion 301 and the vent hole H1 in as linear a direction as possible, thereby more smoothly discharging the vent gas.

[0153] Fig. 16 is a perspective view of an inner cover member 300 according to another embodiment of the present invention as seen from below. Fig. 17 is a partially enlarged cross-sectional view showing the configuration in which the inner cover member 300 of Fig. 16 is attached to the upper part of the cell assembly 100.

[0154] 16 and 17, the inner cover member 300 may have a protrusion, such as the portion indicated by P. Here, the protrusion P may have a shape that protrudes inward toward the cell assembly 100. For example, when the inner cover member 300 is positioned on top of the cell assembly 100, the protrusion P may be configured to protrude downward from the lower surface of the inner cover member 300.

[0155] 16, the protrusion P may be formed to extend long in one direction, particularly in the horizontal direction. In this case, the longitudinal direction of the protrusion P may be the same as the longitudinal direction of the battery cell 110. For example, if the battery cell 110 is formed to be long in the front-rear direction (Y-axis direction), the protrusion P may also be formed to extend long in the front-rear direction.

[0156] Furthermore, the protrusion P may be disposed between adjacent battery cells 110 in the stacking direction of the battery cells 110. For example, as shown in FIG. 17, when a plurality of battery cells 110 are arranged side by side in the left-right direction (X-axis direction), the protrusion P may be disposed at the upper portion between two adjacent battery cells 110. Furthermore, as shown in FIG. 16, a plurality of protrusions P may be provided on one inner cover member 300. In this case, the plurality of protrusions P may be disposed in the upper space between the different battery cells 110.

[0157] In this embodiment, the protrusion P can block the transfer of vent gas or heat between adjacent battery cells 110 or adjacent groups of battery cells 110. In particular, as shown in FIG. 17 , a space may be formed between the cell assembly 100 and the inner cover member 300, as indicated by A10. Vent gas or heat may transfer through this space. However, in this embodiment, the protrusion P can suppress the transfer of vent gas or heat between adjacent battery cells 110. For example, in the embodiment of FIG. 17 , when vent gas is discharged from a specific battery cell 110 to the space A10 above, the protrusion P can minimize the transfer of vent gas in the stacking direction (X-axis direction) of the battery cells 110. This can more effectively suppress the problem of thermal runaway propagation between adjacent battery cells 110 or cell groups.

[0158] In this embodiment, the inner rupture portion 301 may be located between a plurality of protrusions P arranged in the horizontal direction. For example, as shown in FIG. 17 , a plurality of notches N constituting the inner rupture portion 301 may be formed between two protrusions spaced apart in the X-axis direction. Furthermore, the protrusions P may be configured to separate the spaces between the cells or cell groups in the space between the cell assembly 100 and the lower surface of the inner cover member 300. That is, the protrusions P may function as partitions that separate the outer spaces between the battery cells 110. In this case, the inner cover member 300 may be provided with a corresponding inner rupture portion 301 for each battery cell 110 or cell group separated by the protrusions P.

[0159] According to this embodiment of the present invention, it is possible to stably ensure vent performance for each battery cell 110 (or cell group) separated by the protrusion P, and the propagation of thermal runaway can also be more effectively suppressed.

[0160] 17, the cell assembly 100 may further include a barrier 120. Such a barrier 120 may be directly interposed between adjacent battery cells 110 (or groups of cells). In particular, the barrier 120 may be formed in the shape of a substantially upright plate and stacked together with the battery cells 110 to be included in the cell assembly 100.

[0161] Here, the barrier 120 may be a thermal barrier that blocks heat, flame, etc. Such a thermal barrier may include a material with heat insulating properties or fire resistance, and may serve to block heat, flame, etc. between adjacent battery cells 110. For example, the thermal barrier may include a material such as mica or silicone.

[0162] Alternatively, the barrier 120 may be a cooling member, such as a cooling fin, interposed between the cells to perform cooling. In this case, a cooling flow path may be formed in the internal space of the barrier 120. Alternatively, a part or end of the barrier 120 may be configured to be in direct contact with the refrigerant or to be thermally coupled to another cooling structure through which the refrigerant flows.

[0163] Alternatively, the barrier 120 may be interposed between the cells and configured to absorb or buffer swelling or deformation of the battery cells 110. For example, the barrier 120 may be made of an elastic material. In addition, the barrier 120 interposed between the battery cells 110 may be configured with various structures or shapes to have various other purposes or functions.

[0164] In an embodiment in which the barrier 120 is included between the battery cells 110 in this manner, the protrusion P may be configured to be located outside the barrier 120. For example, referring to FIG. 17 , a barrier 120 may be disposed between each group of two battery cells 110. The protrusion P may then be located on top of such a barrier 120.

[0165] According to this embodiment of the present invention, the upper space of the battery cells 110 (cell group) separated by the barrier 120 can also be separated by the protrusion P. Therefore, the propagation of thermal runaway between adjacent battery cells 110 separated by the barrier 120 is effectively suppressed. Furthermore, when the barrier 120 is a thermal barrier or a cooling member, the barrier 120 and the protrusion P can more reliably thermally separate adjacent cells from each other.

[0166] In particular, the protrusion P may be in direct contact with the barrier 120. For example, as in the portion indicated by A11 in FIG. 17 , the lower end of the protrusion P may be configured to be in contact with the upper end of the barrier 120. In this case, the spaces partitioned by the protrusion P and the barrier 120 can be more reliably physically separated. This effectively prevents the transfer of vent gas or heat between the battery cells 110, thereby further improving the effect of preventing heat transfer between adjacent battery cells 110.

[0167] 18 is an enlarged cross-sectional view showing a partial configuration of a battery module according to still another embodiment of the present invention, for example, Fig. 18 can be said to be another modification of the A11 portion of Fig. 17.

[0168] 18, an end of the barrier 120 may be inserted into the protrusion P. More specifically, an insertion groove may be formed in the protrusion P, as shown by the portion I. For example, when the protrusion P is located at the top of the barrier 120, an insertion groove I may be formed on the bottom surface of the protrusion P. The upper end of the barrier 120 may be inserted into this insertion groove I.

[0169] According to this embodiment of the present invention, the spatial separation by the protrusion P and the barrier 120 can be more reliably achieved. In particular, in this case, the movement of vent gas and the like into the gap between the protrusion P and the barrier 120 can be more reliably blocked. In addition, in this case, the bonding strength between the protrusion P and the barrier 120 is improved. As a result, movement or separation of the protrusion P or the barrier 120 is minimized even when pressure is applied by vent gas or flame, and the overall structure of the battery module can be reliably prevented from collapsing. Furthermore, even when vibrations or impacts are applied to the battery module during vehicle operation, the positions of the protrusion P and the barrier 120 are stably maintained. As a result, deformation of the position or stacking state of the cell assembly 100 is prevented or minimized.

[0170] FIG. 19 is a cross-sectional view schematically showing a partial configuration of a battery module according to still another embodiment of the present invention.

[0171] 19, the inner cover member 300 may be configured such that the inner rupture portion 301 is positioned relatively outward compared to other portions. More specifically, in the embodiment of FIG. 19, the inner cover member 300 may be attached to the lower part of the upper plate 220. In this case, the inner cover member 300 may be configured such that the inner rupture portion 301 protrudes relatively upward compared to other portions. In particular, such a protruding configuration may be implemented inside a normal battery module in which no vent gas is generated.

[0172] Furthermore, the inner cover member 300 and the upper plate 220 are configured to be in close contact with each other, and the inner rupture portion 301 may be positioned to correspond to the vent hole H1. Thus, if the inner rupture portion 301 is configured to bulge outward, it may be inserted into the vent hole H1. In particular, if the degree of protrusion of the inner rupture portion 301 is set to a certain level or more, it may protrude outward beyond the vent hole H1.

[0173] Furthermore, when the inner rupture portion 301 is configured to protrude from the inner cover member 300, the inner cover member 300 may have an inclined portion at the inner rupture portion 301 or at a portion facing the inner rupture portion 301. For example, as shown in the portion E in the embodiment of FIG. 19, the inner cover member 300 may have an inclined surface that gradually recedes outward (in the +Z-axis direction) as it approaches the inner rupture portion 301.

[0174] According to this embodiment of the present invention, when vent gas is generated in the cell assembly 100, the vent gas is more easily guided to the inner rupture portion 301, as shown by the dotted arrow in Figure 19. In particular, in this embodiment, the discharge of vent gas is smoothly guided to the inner rupture portion 301 along the inclined portion E of the inner cover member 300. Also, according to this embodiment, since the space on the inner rupture portion 301 side is relatively wide, the vent gas can be concentrated on the inner rupture portion 301 side. This allows the inner rupture portion 301 to rupture more quickly.

[0175] Furthermore, when the inner rupturable portion 301 is inserted into the vent hole H1 as in the above embodiment, the assembly position of the inner cover member 300 is guided, improving the ease of assembly between the inner cover member 300 and the upper plate 220. In this case, the connection between the inner cover member 300 and the upper plate 220 is also improved after assembly.

[0176] Fig. 20 is a perspective view schematically illustrating the configuration of a battery module according to yet another embodiment of the present invention. Fig. 20 shows the upper plate 220 separated from other components. Fig. 21 is an enlarged view of portion A12 in Fig. 20.

[0177] 20 and 21 , the inner cover member 300 may have its end portions folded, as shown by the portion C. For example, as shown in FIG. 20 , the left and right ends of the inner cover member 300 may be folded downward. Such an end folding configuration, i.e., the folded portion C of the inner cover member 300, may be interposed between the cell assembly 100 and the module case 200. For example, as shown in FIG. 21 , the right end of the inner cover member 300 may be folded downward to form a right folded portion. Such a right folded portion C may be interposed between the outermost right edge of the cell assembly 100, e.g., the rightmost battery cell 110, and the right side plate of the U-frame 210. In addition, in the embodiment shown in FIG. 20 , a folded portion C may also be formed on the left side of the inner cover member 300, and such a left folded portion C may be interposed between the outermost left edge of the cell assembly 100 and the left side plate of the U-frame 210.

[0178] According to this embodiment of the present invention, the inner cover member 300 can be more stably positioned in the internal space of the module case 200. In particular, even when pressure due to vent gas or external vibration or impact occurs, the structure in which the end of the inner cover member 300 is interposed between the cell assembly 100 and the module case 200 makes it less likely for displacement or deformation to occur.

[0179] Furthermore, this embodiment can reduce leakage of vent gas through the space between the outermost portion of the cell assembly 100 and the module case 200. For example, referring to the embodiment of Fig. 21, the vent gas that has flowed into the space above the outermost battery cell 110 on the right side can be blocked from moving rightward toward the module case 200 by the right bent portion C. Therefore, in this embodiment, the effect of suppressing gas leakage between the module case 200 (e.g., the side plate of the U-frame 210) and the cell assembly 100 is further improved.

[0180] 20 and 21, the cell assembly 100 may further include an insulating pad 130 at the outermost portion in the stacking direction of the battery cells 110. The insulating pad 130 may include an electrically insulating material such as a polymer and be interposed between the cell assembly 100 and the module case 200. The insulating pad 130 may also include an elastic material, and may be configured to absorb swelling when swelling occurs in the battery cells 110 included in the cell assembly 100.

[0181] In this configuration in which the insulating pad 130 is included at the outermost periphery of the cell assembly 100, the bent portion C of the inner cover member 300 may be located above the insulating pad 130 in the space between the outermost battery cell 110 of the cell assembly 100 and the side plate of the U-frame 210. That is, when the insulating pad 130 is provided at the outermost periphery of the cell assembly 100, a space corresponding to the thickness of the insulating pad 130 may be formed between the outermost battery cell 110 and the module case 200. In this case, the bent portion C of the inner cover member 300 may be inserted into this space.

[0182] According to this embodiment of the present invention, it is possible to improve the connectivity of the inner cover member 300 and minimize the increase in the volume of the battery module due to the inner cover member 300. In particular, the end of the bent portion C of the inner cover member 300 may come into contact with the end of the insulating pad 130. For example, in the embodiment of FIG. 21 , the lower end of the bent portion C may come into contact with the upper end of the insulating pad 130. In this case, it is possible to more effectively prevent the vent gas from leaking to the bent portion C side of the inner cover member 300.

[0183] Fig. 22 is an exploded perspective view schematically illustrating the configuration of a battery module according to yet another embodiment of the present invention. Fig. 23 is an enlarged cross-sectional view of a portion where a vent hole H1 is formed when the battery module of Fig. 22 is assembled. For example, Fig. 23 can be said to show a cross-section along A13-A13' when the battery module of Fig. 22 is assembled.

[0184] 22 and 23, the battery module according to the present invention may further include an outer cover member 400. The outer cover member 400 may be formed on the outside of the module case 200. In particular, the outer cover member 400 may be configured to cover from the outside the side of the module case 200 on which the vent hole H1 is formed. For example, as shown in FIGS. 22 and 23, the outer cover member 400 may be positioned above the top plate 220 on which the vent hole H1 is formed, and may be configured to cover the top of the top plate 220.

[0185] The outer cover member 400 may have an outer rupture portion 401. The outer rupture portion 401 may have the same or similar shape and configuration as the inner rupture portion 301 of the inner cover member 300. In particular, the outer rupture portion 401 may be configured as a notch on the surface of the outer cover member 400. For example, the outer rupture portion 401 may be recessed downward from the outer surface, e.g., the upper surface, of the outer cover member 400, as indicated by N in FIG. 23 . The outer rupture portion 401 may have the same or similar configuration as the inner rupture portion 301 described above. For example, the outer rupture portion 401 may have the same or similar configuration as the inner rupture portion 301 described in the embodiment of FIGS. 3 to 14 . In addition, the outer cover member 400 may be made of the same or similar material as the inner cover member 300. For example, the outer cover member 400 may include or be made of a material such as mica, ceramic, or an inorganic material.

[0186] The outer rupture portion 401 may be formed in a portion corresponding to the vent hole H1. For example, as shown in FIG. 23, the outer rupture portion 401 may be formed above the portion where the vent hole H1 is formed. In this case, the inner rupture portion 301 may be formed below the portion where the vent hole H1 is formed. In other words, the outer rupture portion 401 of the outer cover member 400 and the inner rupture portion 301 of the inner cover member 300 are disposed opposite each other across the vent hole H1.

[0187] In this embodiment, when vent gas flows into the vent hole H1, the outer cover member 400 can be configured to allow the flowing vent gas to be discharged to the outside of the module case 200. That is, the outer cover member 400 blocks the vent hole H1 in a steady state, and when the vent gas flows into the vent hole H1 and the pressure increases, the outer rupture portion 401 ruptures, thereby opening the vent hole H1 to the outside.

[0188] Furthermore, the inner cover member 300 and the outer cover member 400 may be positioned on either side of the module case 200 having the vent hole H1 formed therein. In this case, if the internal pressure of the module case 200 increases, the inner rupturable portion 301 of the inner cover member 300 may rupture first, and then the outer rupturable portion 401 of the outer cover member 400 may rupture.

[0189] According to this embodiment of the present invention, the module case 200 can be more effectively protected from vent gases discharged from other vent holes H1 or other battery modules. In particular, vent gases have extremely high temperatures and may contain flames, sparks, high-temperature particles, and the like. In this case, the module case 200 may melt or be damaged by the external high temperature, or the cell assemblies 100 inside may be thermally damaged or experience thermal runaway propagation. Furthermore, the portion of the module case 200 where the vent hole H1 is formed has weak structural rigidity, and there is a possibility that heat may flow back through the vent hole H1 and damage the inner rupture portion 301. However, when the outer cover member 400 is positioned outside the module case 200 as in the above embodiment, damage to the module case 200 or its internal components or thermal runaway propagation from vent gases and the like present outside the module case 200 can be more effectively prevented. Furthermore, according to one embodiment of the present invention, two fireproof sheets, an inner cover member 300 and an outer cover member 400, are applied to the upper and lower ends of the upper plate 220, respectively, thereby further improving protection from an external high-temperature or high-pressure environment. For example, even if the outer cover member 400 were to burst due to high-temperature, high-pressure vent gas emitted from an adjacent battery module, the inner cover member 300 would still remain inside the upper plate 220. Therefore, the cell assemblies inside the upper plate 220 are effectively protected from external vent gas.

[0190] In particular, the inner cover member 300 and the outer cover member 400 may be in close contact with the module case 200 at the surface where the vent hole H1 is formed. For example, referring to Fig. 23, the outer cover member 400 may be stacked above the upper plate 220, and the inner cover member 300 may be stacked below the upper plate 220.

[0191] In this embodiment, the vent hole H1 formed in the upper plate 220 may be closed (sealed) at the outside (upper) by the outer cover member 400 and at the inside (lower) by the inner cover member 300. Air may be accommodated in the vent hole H1. In this case, an air insulation layer may be formed in the vent hole H1. This air insulation layer may reduce heat transfer to the inside and outside of the battery module. This further improves the effect of suppressing thermal runaway propagation in the battery module.

[0192] For example, thermal runaway of another battery module may cause high-temperature particles to accumulate on the upper surface of the outer cover member 400 of the upper plate 220. In this case, the air insulating layer formed in the vent hole H1 of the upper plate 220 prevents the heat of the external high-temperature particles from being transferred to the inside of the upper plate 220.

[0193] In particular, in the above embodiment, the upper plate 220 and the outer cover member 400, and the upper plate 220 and the inner cover member 300 may be bonded to each other except for the portion where the vent hole H1 is formed. In this case, the air contained in the vent hole H1 may be retained only in the vent hole H1.

[0194] According to this embodiment, the air layer can stably support the outer rupture portion 401 and the inner rupture portion 301 at the vent hole H1. This can reduce deformation or damage, such as warping toward the vent hole H1, that occurs when the outer rupture portion 401 or the inner rupture portion 301 is not securely supported due to gravity, vibration, external impact, or the like. In addition, in this case, if the inner rupture portion 301 deforms toward the vent hole H1 when vent gas is generated and the internal pressure of the module case 200 increases, the outer rupture portion 401 can also be pressurized outward and deformed by the pressure of the air layer. This allows the outer rupture portion 401 to rupture more quickly in a thermal runaway situation. This further improves the venting performance of the battery module.

[0195] In addition, when the outer cover member 400 and the inner cover member 300 are bonded to the module case 200 as in the above embodiment, it is possible to prevent the inflow of vent gas into the gaps between them, thereby suppressing the thermal runaway propagation of the vent gas that has flowed into the gaps to other battery cells 110.

[0196] 24 is a diagram schematically illustrating a partial configuration of a battery module according to yet another embodiment of the present invention. For example, the embodiment illustrated in FIG. 24 may be a modified example of the embodiment illustrated in FIG.

[0197] 24, the outer rupture portion 401 may be at least partially inserted into the vent hole H1. That is, when the battery module is in a stationary state, the outer cover member 400 is attached to the outside of the module case 200, and the portion where the outer rupture portion 401 is formed may be inserted into the vent hole H1. In this case, it can be said that the outer rupture portion 401 is located closer to the inside of the battery module than other portions of the outer cover member 400. For example, as shown in FIG. 24, the outer cover member 400 is attached to the upper surface of the upper plate 220, and the outer rupture portion 401 is recessed downward and is entirely inserted into the vent hole H1. In this case, it can be said that the outer rupture portion 401 is located lower than other portions of the outer cover member 400.

[0198] According to this embodiment of the present invention, the insertion of the outer rupture portion 401 into the vent hole H1 guides the assembly position of the outer cover member 400, improving the assembly of the battery module. In addition, in this case, horizontal movement of the outer cover member 400 attached to the outside of the module case 200 is restricted, improving the connection between the outer cover member 400 and the module case 200.

[0199] Furthermore, according to the above-described embodiment of the present invention, damage to the outer rupture portion 401 caused by vent gas flowing outside the battery module is suppressed. For example, when vent gas discharged from another battery module flows horizontally above the battery module as indicated by the dotted arrow in Fig. 24, it is possible to reduce contact of the vent gas with the outer rupture portion 401. Therefore, in this case, it is possible to more effectively prevent vent gas discharged from another battery module from flowing back in through the vent hole H1.

[0200] 25 is a diagram schematically illustrating a partial configuration of a battery module according to yet another embodiment of the present invention, which may be another modified example of the embodiment of FIG.

[0201] 25, the outer rupture portion 401 has an inwardly recessed shape similar to the embodiment of Fig. 24, but unlike the embodiment of Fig. 24, the inner rupture portion 301 may also have a downwardly recessed shape. That is, in a normal battery module in which thermal runaway has not occurred, the inner rupture portion 301 may be recessed downwardly approximately parallel to the outer rupture portion 401.

[0202] According to this embodiment, it is possible to widen the gap between the inner rupture part 301 and the outer rupture part 401. This ensures a certain level of insulating air layer between the inner rupture part 301 and the outer rupture part 401, thereby further ensuring the insulating effect of the vent hole H1.

[0203] In addition, in the above embodiment, the inner rupture portion 301 and the outer rupture portion 401 may be inverted from a concave shape to a convex shape when the internal pressure increases, as will be described in detail with reference to FIG.

[0204] 26 is a partially enlarged view schematically illustrating a configuration in which the inner cover member 300 and the outer cover member 400 are deformed due to an increase in internal pressure in a battery module according to an embodiment of the present invention. For example, FIG. 26 illustrates the inner cover member 300 and the outer cover member 400 being deformed by vent gas in the embodiment of FIG. 25.

[0205] Referring to FIG. 26, when vent gas is generated inside the module case 200, for example, at the bottom of the inner cover member 300, and the internal pressure increases, the inner rupture portion 301 of the inner cover member 300 may be reversely deformed from a downwardly concave shape as shown in FIG. 25 to an upwardly bulging shape as shown in FIG. 26.

[0206] At this time, the inner rupture part 301 can rupture more quickly due to this reversal deformation. In particular, if a notch is formed in the inner rupture part 301 as indicated by N, the notch is further opened when the inner rupture part 301 is reversed, thereby further increasing the rupture speed of the inner rupture part 301.

[0207] In addition, pressure may be applied to the outer rupture portion 401 by the vent gas or the inner rupture portion 301 as shown by the dotted line in Fig. 26. This pressure application may also cause the outer rupture portion 401 to undergo an inverted deformation from a downwardly concave shape as shown in Fig. 25 to an upwardly bulging shape as shown in Fig. 26. This inverted deformation opens a notch in the outer rupture portion 401, allowing it to rupture quickly.

[0208] According to this embodiment, the rupture speed of the outer rupture part 401 and the inner rupture part 301 can be further improved, thereby further improving the venting performance of the battery module.

[0209] FIG. 27 is a perspective view schematically illustrating the configuration of a battery pack according to one embodiment of the present invention.

[0210] 27, a battery pack according to the present invention may include one or more battery modules according to the present invention as described above, as shown in M. Furthermore, the battery pack according to the present invention may further include various other components in addition to the battery module M according to the present invention. For example, the battery pack according to the present invention may further include components of a battery pack that are known at the time of filing of the present invention, such as a BMS (Battery Management System), bus bars, relays, current sensors, etc.

[0211] The battery pack according to the present invention may further include a pack case PC as shown in FIG. 27. The pack case PC may provide a space for accommodating the battery module M according to the present invention. In particular, when the battery pack includes multiple battery modules M, the pack case PC may be partitioned into spaces for accommodating the multiple battery modules by cross beams or the like. A venting device VD may be provided on at least one side of the pack case PC of the battery pack according to the present invention. The venting device VD may serve to exhaust vent gas discharged from the vent holes H1 of each battery module from the inside of the pack case PC to the outside. The venting device VD may be configured to always remain open or to switch from a closed state to an open state in a specific situation, such as when the internal pressure increases.

[0212] In another example, a battery pack according to the present invention may include a battery module according to the present invention, but may not include a separate pack case. Instead, the module case 200 of the battery module may function as the pack case PC. In this case, battery pack components such as a BMS, bus bars, and relays may be included inside the module case 200. This type of battery pack is also called a cell-to-pack (CTP) type because the battery cells 110 are directly housed in the pack case PC. Recently, development of such CTP-type battery packs has been actively conducted, and the present invention is also applicable to such CTP-type battery packs. In this case, a vent hole H1 may be formed in the case member that is both the pack case PC and the module case 200, and an inner cover member 300 may be located inside this case member. In addition, an outer cover member 400 may be located outside this pack case.

[0213] The battery module or battery pack according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, the automobile according to the present invention may include the battery module according to the present invention or the battery pack according to the present invention. Furthermore, the automobile according to the present invention may further include various other components included in the automobile in addition to the battery module or battery pack. For example, the automobile according to the present invention may further include a vehicle body, a motor, a control device such as an ECU (electronic control unit), etc. in addition to the battery module according to the present invention.

[0214] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is of course possible for a person having ordinary skill in the art to which the present invention pertains to make various modifications and variations within the scope of the technical spirit of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0215] 100 Cell Assembly 110 battery cells 111 Electrode terminal 120 Barrier 130 Insulation Pad 200 Module Case 210 U-frame 211 Base Plate 212 Left side plate 213 Right side plate 220 Upper Plate 230 End Frame 300 Inner cover member 301 Internal rupture part 400 outer cover member 401 External rupture part H1 Vent Hole N notch P protrusion C Bending part

Claims

1. a cell assembly including a plurality of battery cells stacked together; a module case configured to house the cell assembly in its internal space and having a vent hole; an inner cover member covering the side surface of the module case where the vent hole is formed from the inside of the module case, the inner cover member having an inner rupture part at a portion corresponding to the vent hole, and configured to allow vent gas ejected from the cell assembly to be discharged to the vent hole through the inner rupture part.

2. The vent hole is formed in the upper part of the module case, The battery module according to claim 1 , wherein the inner cover member is located on top of the cell assembly.

3. 2. The battery module according to claim 1, wherein the module case comprises a U-frame having a base plate, a left plate, and a right plate integrally formed therewith, and an upper plate coupled to an upper end of the U-frame.

4. The battery module according to claim 1 , wherein the inner rupture portion has a notch shape.

5. The battery module according to claim 1 , wherein the inner rupture portion is formed in plurality.

6. The battery module according to claim 5 , wherein at least some of the plurality of inner rupture sections are configured to have different rupture conditions.

7. The battery module according to claim 1 , wherein the inner rupture portion is configured to have different rupture conditions depending on the position at a portion corresponding to the vent hole.

8. the cell assembly includes a pouch-type cell as the battery cell, 2. The battery module according to claim 1, wherein the pouch-type cell has an adhesive member partially attached to the sealing portion to maintain the folded structure of the sealing portion, and at least a portion of the portion to which the adhesive member is not attached is located corresponding to the inner rupture portion.

9. The battery module according to claim 1 , wherein the inner cover member has a protrusion that protrudes toward the cell assembly.

10. The battery module according to claim 1 , wherein the inner rupture portion of the inner cover member is positioned relatively outward.

11. The battery module according to claim 1 , wherein the inner cover member has a folded end, and the folded end is interposed between the cell assembly and the module case.

12. 10. The battery module according to claim 1, further comprising an outer cover member covering the side surface of the module case where the vent hole is formed from the outside of the module case, the outer cover member having an outer rupture portion at a portion corresponding to the vent hole.

13. The battery module according to claim 12, wherein the outer rupture part is inserted into the vent hole.

14. A battery pack comprising the battery module according to any one of claims 1 to 13.

15. A motor vehicle comprising a battery module according to any one of claims 1 to 13.

Images