Battery module, and battery pack and vehicle comprising same

Abstract

A battery module according to the present invention may comprise: a cell stack including a plurality of battery cells; a case accommodating the cell stack and including a top plate having at least one first venting portion configured to discharge venting gas; a flexible cover disposed on the case, and including at least one second venting portion formed at a position corresponding to the first venting portion and configured to discharge the venting gas; and a hard cover disposed on the flexible cover and divided into a plurality of regions having thicknesses different from each other.

Description

Battery module, battery pack including the same, and automobile

[0001] The present invention relates to a battery module, a battery pack including the same, and an automobile.

[0002] This application is a priority application for Korean Patent Application No. 10-2025-0013539 filed on February 4, 2025, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003]

[0004] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product categories, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources.

[0005] These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, not only for the primary advantage of being able to drastically reduce the use of fossil fuels, but also because they do not generate any by-products from the use of energy.

[0006] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. When a high output voltage is required, multiple battery cells are connected in series to form a battery module or battery pack. Additionally, to increase charge / discharge capacity, multiple battery cells are connected in parallel to form a battery module or battery pack. Therefore, the number of battery cells included in the battery module or pack can be varied depending on the required output voltage or charge / discharge capacity.

[0007] When configuring a battery pack by connecting multiple battery cells in series or parallel, it is common practice to first construct a battery module containing at least one battery cell, and then use this at least one battery module to add other components to form a battery pack or battery rack. Alternatively, recently, battery packs in the form of a "Cell-to-Pack," in which multiple battery cells are directly housed in a pack housing without modularization, are also being manufactured.

[0008] However, when multiple battery modules are contained within a battery pack in this manner, it can be vulnerable to thermal chain reactions between the modules. For example, if an event such as thermal runaway occurs within a single battery module, this runaway can propagate to other battery modules. If the propagation of thermal runaway between battery modules is not properly suppressed, an event originating in a specific module can trigger a chain reaction across multiple modules, potentially causing serious problems such as explosions or fires.

[0009] In particular, when a battery module contains multiple battery cells, high-temperature gases, flames, sparks, etc., generated during thermal runaway in a specific battery cell are highly likely to be ejected forward and backward toward the battery cells where the electrode leads of that battery module are located.

[0010] Therefore, there is a need to develop a structure capable of delaying thermal runaway between battery cells or battery modules by preventing the emission of high-temperature gases or flames from a battery cell or appropriately controlling the direction of emission when a thermal event occurs in a single battery cell, and simultaneously preventing the reverse inflow of external high-temperature gases or flames.

[0011]

[0012] Therefore, the problem that the present invention aims to solve is to provide a battery module with improved safety and reliability by appropriately controlling the venting direction of high-temperature gases or flames generated in battery cells during abnormal situations of the battery module, and preventing the reverse inflow of external high-temperature gases or flames, thereby effectively preventing heat propagation between battery cells or battery modules.

[0013] Another technical objective of the present invention is to provide a battery pack including a battery module of an improved structure, and a vehicle including the battery pack.

[0014] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below.

[0015]

[0016] To solve the above problem, a battery module according to the present invention may include a cell stack comprising a plurality of battery cells, a case having a top plate having at least one first venting portion configured to discharge venting gas as a case for housing the cell stack, a flexible cover disposed on the case and having at least one second venting portion formed at a position corresponding to the first venting portion and configured to discharge venting gas, and a hard cover disposed on the flexible cover and divided into a plurality of regions having different thicknesses.

[0017] The hard cover may be divided into a first region formed with a first thickness corresponding to the first venting portion and a second region formed with a second thickness thicker than the first thickness, which is the remaining region excluding the first region.

[0018] The lower surface of the hard cover facing the flexible cover may have the first region recessed in an upward direction compared to the second region.

[0019] The lower surface of the above hard cover may be subjected to pressure of venting gas exiting in the outward direction of the battery module, limited to the above first region.

[0020] The upper surface of the hard cover, which is the opposite side of the surface facing the flexible cover, may be formed as a flat surface.

[0021] The upper surface of the hard cover may be subjected to pressure of venting gas entering from the outside of the battery module inwardly to the first region and the second region.

[0022] The contact area between the venting gas exiting from the inside of the battery module in an outward direction and the hard cover may be narrower than the contact area between the venting gas entering from the outside of the battery module in an inward direction and the hard cover.

[0023] The surface pressure acting on the hard cover by the venting gas exiting from the inside of the battery module in an outward direction may be configured to be higher than the surface pressure acting on the hard cover by the venting gas entering from the outside of the battery module in an inward direction.

[0024] The first region may be configured to be separated from the second region when a thermal event occurs in the battery cell.

[0025] The first region separated from the second region may be configured to cover at least a portion of the first venting section when moved downward.

[0026] The first region is configured to be separated from the second region by external pressure, and the first region separated from the second region may be configured to cover at least a portion of the first venting part when moved downward.

[0027] The size of the first region may be formed to be larger than the size of the first venting portion.

[0028] At least one of the hard cover and the flexible cover may include a mica material.

[0029] The hard cover may be made of a material with a higher hardness than the flexible cover.

[0030] The flexible cover may be configured to cover at least three sides of the case to protect the battery cells within the battery module from venting gas outside the battery module.

[0031] The flexible cover may comprise an upper cover that covers the upper side of the case and has the second venting portion formed therein, a left cover that extends from the upper cover so as to be foldable and covers the left side of the case, and a right cover that extends from the upper cover so as to be foldable and covers the right side of the case.

[0032] The battery module of the present invention may further comprise a first adhesive member disposed between the case and the flexible cover and a second adhesive member disposed between the flexible cover and the hard cover.

[0033] The size of the second venting portion may be formed to be larger than the size of the first venting portion.

[0034] In addition, the present invention provides a battery pack characterized by including a battery module according to the present invention.

[0035] And, the present invention provides an automobile characterized by including a battery module according to the present invention.

[0036]

[0037] According to one aspect of the present invention, high-temperature gases or flames generated in a battery cell within a battery module can be rapidly discharged to the outside by inducing directional venting upward. This ensures the safety and reliability of the battery module.

[0038] In addition, according to another aspect of the present invention, by preventing external high-temperature gas or flames from flowing back into the interior of the battery module, it is possible to effectively prevent or delay the transfer of gas or flames to adjacent battery modules where an event occurred, thereby causing thermal runaway.

[0039] In addition, according to another aspect of the present invention, high-temperature gases or flames discharged to the outside of the battery module can be prevented from flowing back into the interior of the battery module.

[0040] In addition, according to another aspect of the present invention, events such as fire or explosion caused by thermal runaway phenomena in a battery pack including a plurality of battery modules or a device equipped with them can be prevented or delayed.

[0041] In addition to the above, the present invention may have various other effects, which are described in each embodiment, or effects that can be easily inferred by those skilled in the art, etc., will be omitted.

[0042]

[0043] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0044] FIG. 1 is a front perspective view of a battery module according to one embodiment of the present invention.

[0045] FIG. 2 is an exploded perspective view of a battery module according to one embodiment of the present invention.

[0046] Figure 3 is a cross-sectional view of the upper side of the battery module of Figure 1 cut along line A-A'.

[0047] Figure 4 is a diagram showing the pressure of the venting gas, etc. acting in Figure 3.

[0048] FIG. 5 is a drawing showing a battery module with a first pressure applied according to one embodiment of the present invention.

[0049] FIG. 6 is a drawing showing a second pressure applied to a battery module according to one embodiment of the present invention.

[0050] FIG. 7 is an unfolded view showing the unfolded state of a flexible cover of a battery module according to one embodiment of the present invention.

[0051] FIG. 8 is a drawing showing a battery module according to one embodiment of the present invention viewed from the front.

[0052] FIG. 9 is a graph showing the pressure range at which the hard cover ruptures when a first pressure is applied to the battery module in the battery module of the comparative example and the battery module of the present invention.

[0053] FIG. 10 is a graph showing the pressure range at which the hard cover ruptures when a second pressure is applied to the battery module in the battery module of the comparative example and the battery module of the present invention.

[0054] FIG. 11 is a cross-sectional view of the upper side of a battery module according to another embodiment of the present invention, cut along line A-A' of FIG. 1.

[0055] FIG. 12 is a drawing showing a second pressure applied to a battery module according to another embodiment of the present invention.

[0056] FIG. 13 is a cross-sectional view of the upper side of a battery module according to another embodiment of the present invention, cut along line A-A' of FIG. 1.

[0057] FIG. 14 is a cross-sectional view of the upper side of a battery module according to another embodiment of the present invention, cut along line A-A' of FIG. 1.

[0058] FIG. 15 is a drawing showing a second pressure applied to a battery module according to another embodiment of the present invention.

[0059] FIG. 16 is a schematic perspective view of a battery pack including a battery module according to one embodiment of the present invention.

[0060] FIG. 17 is a schematic perspective view of a vehicle including a battery pack according to one embodiment of the present invention.

[0061]

[0062] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0063] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0064] In addition, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar configurations are omitted, and the focus is on the differences.

[0065] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0066] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0067] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0068] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0069] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0070] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0071] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0072] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back may be used in the present invention, these terms are used merely for convenience of explanation and may vary depending on the position of the object or the position of the observer, as is obvious to those skilled in the art of the present invention.

[0073] For example, in an embodiment of the present invention, the X-axis direction shown in the drawing may mean the left-right direction, the Y-axis direction may mean the front-back direction perpendicular to the X-axis direction on the horizontal plane (XY plane), i.e., the length direction of the battery cell, and the Z-axis direction may mean the up-down direction (vertical direction), i.e., the height direction of the battery cell, which is perpendicular to both the X-axis direction and the Y-axis direction.

[0074] FIG. 1 is a front perspective view of a battery module according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of a battery module according to one embodiment of the present invention.

[0075] Referring to FIGS. 1 and 2, a battery module (10) according to one embodiment of the present invention may include a cell stack (100), a case (200), a flexible cover (300), and a hard cover (400).

[0076] The cell stack (100) may include battery cells (110). The battery cells (110) may be provided in multiple numbers. In this case, the multiple battery cells (110) may be electrically connected to each other.

[0077] Multiple battery cells (110) can be stacked along one direction. For example, as shown in FIG. 2, multiple battery cells (110) can be arranged side by side in the left-right direction (X-axis direction) while standing upright in the vertical direction (Z-axis direction).

[0078] More specifically, a plurality of battery cells (110) may include an electrode assembly and a cell case (e.g., a pouch outer material) that accommodates the electrode assembly. The cell case may be a laminate sheet comprising a resin layer and a metal layer.

[0079] Additionally, a plurality of battery cells (110) may each be provided with an electrode lead (112). The electrode lead (112) is connected to an electrode assembly and can be drawn out to the outside of the cell case to function as an electrode terminal.

[0080] The electrode leads (112) may be provided as a pair, and the pair of electrode leads (112) may be drawn out at both ends of the battery cell (110), i.e., in the longitudinal direction (Y direction). The electrode leads (112) may be configured to protrude toward the front and / or rear side of the sealing portion of the battery cell (110). In this case, the pair of electrode leads (112) may be a positive lead and a negative lead.

[0081] Meanwhile, the present invention is not limited by the specific type or shape of such battery cell (110), and various battery cells (110) known at the time of filing the present invention may be employed to constitute the battery module (10) of the present invention. In this embodiment, a pouch-type secondary battery with high energy density and easy stacking is used as shown in the drawing, but it is understood that cylindrical or prismatic secondary batteries may also be applied as battery cells (110).

[0082] A case (200) may be configured to accommodate a cell stack (100). Specifically, the case (200) may be configured to have a receiving space formed therein and to accommodate the cell stack (100) in the receiving space. Such a case (200) may be made of a metal material having rigidity and heat resistance to physically or chemically protect the accommodated cell stack (100).

[0083] More specifically, referring to FIGS. 1 and FIGS. 2, the case (200) may include a case body (210), a front end cover (220), and a rear end cover (230).

[0084] The case body (210) may include a U-frame (211) and a top plate (212). The U-frame (211) may include a pair of side plates covering the left and right sides of the cell stack (100) and a base plate covering the bottom surface of the cell stack (100). The pair of side plates and the base plate may be formed integrally.

[0085] The top plate (212) may be configured to cover the upper surface of the cell stack (100). This top plate (212) may be joined to the U-frame (211) by welding. This case body (210) may be formed in a rectangular tubular shape with the front and rear open. As an alternative to the present embodiment, a monoframe-type case (200) in which the U-frame (211) and the top plate (212) are integrated may be adopted.

[0086] The front end cover (220) and the rear end cover (230) can be attached to the open front and rear of the case body (210), respectively. The front end cover (220) and the rear end cover (230) can be attached to the case body (210) by welding or a snap-fit ​​structure.

[0087] The top plate (212) may have at least one first venting section (2121) configured to discharge venting gas. The first venting section (2121) may be configured to discharge venting gas generated in the battery cell (110) to the outside of the case (200). One-way directional venting may be possible by the first venting section (2121).

[0088] The first venting section (2121) may be provided in multiple numbers. The multiple first venting sections (2121) may be arranged at regular intervals from each other in the horizontal direction (X-axis, Y-axis direction). The first venting sections (2121) may be arranged side by side by alignment in the width direction (X-axis direction) and / or the length direction (Y-axis direction). The first venting section (2121) may be formed to extend in the length direction. However, the size, shape, and / or arrangement of the first venting section (2121) are not limited by the above embodiment and may be modified in various ways.

[0089] According to one embodiment, with reference to FIG. 2, the first venting portion (2121) may be a venting hole.

[0090] According to another embodiment, although not illustrated in the drawings, the first venting portion (2121) may be configured to break easily when venting gas is discharged from the battery cell (110). For example, the first venting portion (2121) may include a break line or a preliminary cut line configured to break by explosive pressure. For example, the first venting portion (2121) may be thinner or have a lower density than the surrounding area of ​​the top plate (212), making it easier to break than the surrounding area.

[0091] According to the above embodiment of the present invention, in a situation where one of the plurality of battery cells (110) undergoes thermal runaway and generates gas, etc., high-temperature venting gas, etc. can be rapidly discharged to the outside of the battery module (10) through the first venting section (2121). In addition, directional venting toward the upper direction of the battery module (10) can be induced through the first venting section (2121).

[0092] A flexible cover (300) may be placed on the case (200). The flexible cover (300) may be configured to suppress the transfer of venting gas or flames, etc., emitted when a thermal event occurs within the battery module (10) to another battery module (10). Additionally, it may be configured to protect the battery module (10) from external venting gas, etc. That is, the flexible cover (300) has strong heat resistance and pressure resistance, so it can delay or minimize thermal runaway.

[0093] The flexible cover (300) may have at least one second venting section (301) configured to discharge venting gas. The second venting section (301) may be formed at a position corresponding to the first venting section (2121). The second venting section (301) and the first venting section (2121) may be configured to communicate in a vertical direction (Z-axis direction). The second venting section (301) may be configured to discharge the venting gas discharged through the first venting section (2121) to the outside of the battery module (10).

[0094] The second venting section (301) may be provided in multiple numbers. The multiple second venting sections (301) may be arranged at regular intervals from each other in the horizontal direction (X-axis, Y-axis direction). The second venting sections (301) may be arranged side by side by alignment in the width direction (X-axis direction) and / or the length direction (Y-axis direction). The second venting section (301) may be formed to extend in the length direction. However, the size, shape, and / or arrangement of the second venting section (301) are not limited by the above embodiment and may be modified in various ways.

[0095] Referring to FIG. 2, the second venting section (301) may be a venting hole. Due to the material properties of the flexible cover (300), it has higher ductility compared to the hard cover (400), so it may be difficult to break even under high temperature and high pressure. According to the above embodiment of the present invention, a hole for venting is formed in the second venting section (301) so that venting gas or flames generated from the internal battery cell (110) can be quickly directionally vented toward the upper direction of the battery module (10).

[0096] Referring to FIGS. 1 and 2, a hard cover (400) may be placed on the flexible cover (300). The hard cover (400) may cover the upper side of the battery module (10). The hard cover (400) may cover the first venting portion (2121) and the second venting portion (301).

[0097] For example, the hard cover (400) may be configured to prevent venting gas or flames emitted from another battery module (10) from entering the inside of the case (200) through the first venting section (2121) and the second venting section (301).

[0098] According to the above embodiment of the present invention, the hard cover (400) may be configured to effectively suppress the transfer of venting gas or flames, etc. emitted when a thermal event occurs within the battery module (10) to another battery module (10). Additionally, it may be configured to protect the battery module (10) from external venting gas, etc.

[0099] The hard cover (400) and / or the flexible cover (300) may be made of a material having excellent heat resistance and / or fire resistance, such as a mica sheet or a silicone composite material. At least one of the hard cover (400) and the flexible cover (300) may include a mica material. For instance, the hard cover (400) may be made of a non-flexible material by thermoforming a mica sheet.

[0100] Thus, the hard cover (400) and / or the flexible cover (300) can maintain structural stability without deformation even when high-temperature heat is generated, thereby stably blocking high-temperature gas or flames generated in the battery cell (110).

[0101] According to the above embodiment of the present invention, since the hard cover (400) and / or the flexible cover (300) are provided with a hard and heat-resistant material, deformation caused by high-temperature gas or flame, etc. can be minimized.

[0102] The hard cover (400) may be made of a material with a higher hardness than the flexible cover (300). Therefore, the hard cover (400) is relatively more rigid and can protect the inside of the battery module (10) from external pressure or high temperature. In addition, the flexible cover (300) may be relatively easy to bend and can protect the edge portions or connection portions, which are relatively vulnerable to protection, from external pressure or high temperature.

[0103] FIG. 3 is a cross-sectional view of the upper side of the battery module of FIG. 1 cut along line A-A'. FIG. 4 is a diagram showing the application of pressure, such as venting gas, in FIG. 3.

[0104] The hard cover (400) may be divided into multiple regions of different thicknesses. For example, irregularities may be formed on the hard cover (400). For example, steps may be formed on the hard cover (400).

[0105] The hard cover (400) can be divided into a first region (410) and a second region (420) with different thicknesses.

[0106] The first area (410) is an area corresponding to the first venting section (2121) and the second venting section (301), and the second area (420) may be the remaining area excluding the first area (410). The first area (410) may be positioned vertically with respect to the first venting section (2121) and the second venting section (301). The first area (410) may cover the upper side of the first venting section (2121) and the second venting section (301). Additionally, the first area (410) may be surrounded by the second area (420).

[0107] The second area (420) may face the flexible cover (300). The second area (420) may come into surface contact with the flexible cover (300). The second area (420), the flexible cover (300), and the top plate (212) may be stacked sequentially in a vertical direction.

[0108] The first region (410) may be formed with a first thickness (T1), and the second region (420) may be formed with a second thickness (T2) that is thicker than the first thickness (T1). At this time, the first region (410) may be formed with a thinner thickness than the second region (420) and may break relatively easily.

[0109] Thus, according to the above embodiment of the present invention, the inflow of external venting gas, etc. is blocked primarily, and at the same time, the first region (410) is formed to be easily broken so that when a thermal event occurs in the battery cell (110), internal venting gas, etc. can be quickly discharged to the outside.

[0110] More specifically, the lower surface of the hard cover (400) facing the flexible cover (300) may be in a form where the first region (410) is recessed upward from the second region (420).

[0111] Additionally, the upper surface of the hard cover (400), which is the opposite side to the side facing the flexible cover (300), may be formed as a flat surface. That is, the upper surface of the hard cover (400) is flat, and a step may be formed on the lower surface.

[0112] According to the above embodiment of the present invention, the hard cover (400) may have different surface pressure and pressure areas receiving from venting gas, etc. on the upper and lower surfaces.

[0113] For example, if a thermal event occurs in a battery cell (110) inside a battery module (10), the venting gas generated inside may pass through the first venting section (2121) and the second venting section (301) and come into contact with the hard cover (400). At this time, the venting gas is blocked by the hard cover (400), causing pressure to be generated, which can be defined as the first pressure (e.g., open pressure) (P1). The first pressure (P1) may act in an upward direction (or outward direction).

[0114] At this time, referring to FIG. 4, the lower surface of the hard cover (400) may be subjected to the pressure (first pressure) (P1) of the venting gas exiting outward from the battery module (10) only in the first area (410). Since the first area (410) is located above the first venting section (2121) and the second venting section (301), it can directly receive the first pressure (P1) when a thermal event occurs. That is, the first pressure (P1) may act only on the first area (410) of the hard cover (400). The first pressure (P1) may be concentrated on the first area (410) of the hard cover (400).

[0115] On the other hand, since the second region (420) is not facing the first venting section (2121) and the second venting section (301), the first pressure (P1) may not be applied directly. Additionally, since the second region (420) is in surface contact with the flexible cover (300), the first pressure (P1) may not be applied.

[0116] According to the above embodiment of the present invention, by reducing the contact area with the first pressure (P1), the surface pressure can be increased to induce the first region (410) of the hard cover (400) to rupture quickly.

[0117] For example, a thermal event may occur in an adjacent battery module (10), or venting gas discharged to the outside may be directed back into the interior of the battery module (10). At this time, the venting gas is blocked by the hard cover (400), causing pressure to be generated, which can be defined as a second pressure (e.g., reverse pressure) (P2). The second pressure (P2) may act in a downward direction (or inward direction).

[0118] At this time, the upper surface of the hard cover (400) may be subjected to the pressure of the venting gas entering from the outside of the battery module (10) inwardly to the first region (410) and the second region (420). In other words, the second pressure (P2) may be distributed not only to the first region (410) but also to the second region (420). The second pressure (P2) may act equally on the first region (410) and the second region (420).

[0119] Consequently, the contact area between the venting gas exiting from the inside of the battery module (10) in an outward direction and the hard cover (400) may be narrower than the contact area between the venting gas entering from the outside of the battery module (10) in an inward direction and the hard cover (400).

[0120] Additionally, the surface pressure acting on the hard cover (400) by the venting gas exiting from the inside of the battery module (10) in an outward direction can be configured to be higher than the surface pressure acting on the hard cover (400) by the venting gas entering from the outside of the battery module (10) in an inward direction.

[0121] For example, assuming that the same amount of venting gas approaches from the outside and inside of the battery module (10), the venting gas entering from the outside of the battery module (10) can come into contact with a relatively larger area, so the pressure acting per unit area (surface pressure) may be lower. Additionally, the venting gas exiting from the inside of the battery module (10) outward can come into contact with a relatively smaller area, so the pressure acting per unit area (surface pressure) may be higher.

[0122] Meanwhile, the upper side of the battery cell (110) may be protected by a top plate (212), a flexible cover (300), and a hard cover (400). At this time, the top plate (212), the flexible cover (300), and the hard cover (400) may be bonded together. According to one embodiment, the battery module (10) according to the present invention may further comprise a first adhesive member (501) disposed between the case (200) and the flexible cover (300), and a second adhesive member (502) disposed between the flexible cover (300) and the hard cover (400).

[0123] The first adhesive member (501) and / or the second adhesive member (502) may include, for example, an adhesive, an adhesive tape, etc. For example, the first adhesive member (501) and / or the second adhesive member (502) may be a thermally conductive adhesive.

[0124] FIG. 5 is a drawing showing a first pressure applied to a battery module according to an embodiment of the present invention. FIG. 6 is a drawing showing a second pressure applied to a battery module according to an embodiment of the present invention.

[0125] The first region (410) of the hard cover (400) may be configured to be separated from the second region (420) when a thermal event occurs in the battery cell (110). The first region (410) may be more susceptible to pressure than the second region (420). That is, the first region (410) may be more easily broken than the second region (420).

[0126] At this time, the rupture rate caused by the first pressure (P1) of the first region (410) may be higher than the rupture rate caused by the second pressure (P2). That is, when the first pressure (P1) of the first region (410) is applied, it can be easily broken even by less pressure compared to the second pressure (P2).

[0127] According to the above embodiment of the present invention, the rate of rupture of the hard cover (400) when a second pressure (P2) is applied can be lowered, and the rate of rupture of the hard cover (400) when a first pressure (P1) is applied can be increased.

[0128] Therefore, high-temperature gas or flames generated inside the battery module (10) can be quickly discharged to the outside. At the same time, by preventing the external high-temperature gas or flames from flowing back into the battery module (10), it is possible to effectively prevent or delay the transfer of gas or flames to the battery module (10) where the event occurred and to adjacent battery modules (10), thereby causing thermal runaway.

[0129] Referring to FIG. 6, the first region (410), separated from the second region (420), may be configured to cover at least a portion of the first venting section (2121) when moved downward.

[0130] For example, if a second pressure (P2) is applied to the first region (410) and it ruptures, the separated first region (410) may fall downward.

[0131] Additionally, for example, when the first region (410) is separated from the second region (420) by external pressure and the first region (410) separated from the second region (420) moves downward, it may be configured to cover at least a portion of the first venting section (2121).

[0132] Additionally, although not illustrated in the drawing, for example, even if the first pressure (P1) is applied to the first region (410) and causes it to rupture, the separated first region (410) may rise upward due to the first pressure (P1) and then fall back down. At this time, the first region (410) that falls downward may cover at least a portion of the first venting section (2121).

[0133] According to the above embodiment of the present invention, even if the hard cover (400) is ruptured, the separated first region (410) covers the first venting section (2121), thereby preventing external high-temperature gas or flames from flowing back into the interior of the battery module (10). Accordingly, it is possible to effectively prevent or delay the transfer of gas or flames to the battery module (10) where the event occurred and to the adjacent battery module (10), thereby causing thermal runaway.

[0134] With reference primarily to FIG. 6, the size of the first region (410) may be formed to be larger than the size of the first venting section (2121). The diameter (L1) of the first region (410) may be larger than the diameter (L2) of the first venting section (2121). Here, the diameter (L1) of the first region (410) and the diameter (L2) of the first venting section (2121) may be diameters measured in the width direction or diameters measured in the length direction.

[0135] According to the above embodiment of the present invention, the first region (410), separated from the second region (420), may be seated on the top plate (212) rather than penetrating the first venting portion (2121). That is, the first region (410), separated from the second region (420), may come into contact with a part of the top plate (212). The first region (410), separated from the second region (420), may come into contact with one surface of the top plate (212) surrounding the first venting portion (2121).

[0136] The size of the second venting section (301) may be formed to be larger than the size of the first venting section (2121). The size of the second venting section (301) may be substantially the same as or larger than the size of the first area (410). For example, referring to FIG. 6, the size of the second venting section (301) may be substantially the same as the size of the first area (410). According to the above embodiment of the present invention, when the separated first area (410) falls downward, it may not get caught on the second venting section (301). However, the size of the second venting section (301) may not be limited by the above embodiment.

[0137] FIG. 7 is an unfolded view showing the flexible cover of a battery module according to one embodiment of the present invention. FIG. 8 is a drawing showing the battery module according to one embodiment of the present invention viewed from the front.

[0138] The flexible cover (300) may be configured to cover at least three sides of the case (200). The flexible cover (300) may be foldable. The flexible cover (300) may have an upper cover (310), a right cover (320), and a left cover (330). In this case, the upper cover (310), the right cover (320), and the left cover (330) may be formed integrally. The flexible cover (300) may have a U-frame shape.

[0139] The upper cover (310) covers the upper side of the case (200) and the second venting portion (301) may be formed. The second venting portion (301) of FIG. 7 may be substantially the same as the second venting portion (301) of FIG. 2 to FIG. 6.

[0140] The left cover (330) is extended from the upper cover (310) so as to be foldable and can cover the left side of the case (200). The right cover (320) is extended from the upper cover (310) so as to be foldable and can cover the right side of the case (200).

[0141] In particular, the hard cover (400) can prevent reverse inflow in the upward direction, but it cannot prevent the inflow of external high-temperature gas or flames in the side direction. According to the above embodiment of the present invention, when referring to the part marked A in FIG. 8, the flexible cover (300) can prevent external high-temperature gas or flames from entering from the side and / or the boundary between the upper surface and the side. The battery module (10) according to the present invention can effectively protect the battery cell inside the battery module (10) from external venting gas by further providing a foldable flexible cover (300) in addition to the hard cover (400).

[0142] FIG. 9 is a graph showing the pressure range at which the hard cover ruptures when a first pressure is applied to the battery module of the comparative example and the battery module of the present invention. FIG. 10 is a graph showing the pressure range at which the hard cover ruptures when a second pressure is applied to the battery module of the comparative example and the battery module of the present invention.

[0143] The battery module (C) of the comparative example differs only in that it does not have a flexible cover (300) and a hard cover (400) as in the battery module (10) of the present invention. For example, the cover of the battery module (C) of the comparative example may not be divided into multiple regions of different thicknesses, unlike the hard cover (400) of the present invention. For example, the battery module (C) of the comparative example may not have a cover covering a venting hole formed in the case placed at the outermost edge. In other words, the contact area between the venting gas exiting from the inside of the battery module to the outside and the cover of the battery module (C) of the comparative example may not be narrower than the contact area between the venting gas entering from the outside of the battery module to the inside and the cover of the cover.

[0144] Referring to FIG. 9, the battery module (C) of the comparative example may have its cover corresponding to the hard cover (400) of the present invention destroyed at approximately 1.1 bar or more and 2.0 bar or less. The battery module (C) of the comparative example may have its cover corresponding to the hard cover (400) of the present invention destroyed at an average of approximately 1.3 bar or more and 1.8 bar or less.

[0145] Additionally, the hard cover (400) of the battery module (10) of the present invention may be destroyed at approximately 1.1 bar or more and 1.7 bar or less. The hard cover (400) of the battery module (10) of the present invention may be destroyed at an average of approximately 1.25 bar or more and 1.5 bar or less.

[0146] That is, when a first pressure (P1) is applied, in a battery module (10) equipped with a flexible cover (300) and a hard cover (400) according to an embodiment of the present invention, it can be confirmed that the hard cover (400) ruptures even under a lower pressure. Therefore, high-temperature gas or flames generated in the battery cell (110) within the battery module (10) can be quickly discharged to the outside. Thus, the safety and reliability of the battery module (10) can be guaranteed.

[0147] Referring to FIG. 10, the battery module (C) of the comparative example may have its cover corresponding to the hard cover (400) of the present invention destroyed at approximately 1.2 bar or more and 2.1 bar or less. The battery module (C) of the comparative example may have its cover corresponding to the hard cover (400) of the present invention destroyed at an average of approximately 1.5 bar or more and 1.9 bar or less.

[0148] Additionally, the hard cover (400) of the battery module (10) of the present invention may be destroyed at approximately 2.1 bar or more and 3.4 bar or less. The hard cover (400) of the battery module (10) of the present invention may be destroyed at an average of approximately 2.5 bar or more and 3.0 bar or less.

[0149] That is, when a second pressure (P2) is applied, in a battery module (10) equipped with a flexible cover (300) and a hard cover (400) according to an embodiment of the present invention, it can be confirmed that the hard cover (400) ruptures at a higher pressure. Therefore, external high-temperature gas or flames can be prevented as much as possible from entering the interior of the battery module, and the thermal runaway caused by the event spreading to the battery module where the event occurred and to adjacent battery modules can be effectively prevented or delayed.

[0150] Consequently, when a thermal event occurs, high temperature and / or high pressure venting gas inside the battery module (10) can be quickly discharged to the outside, and at the same time, the inflow of external venting gas into the inside can be prevented or delayed, thereby delaying thermal runaway.

[0151] FIG. 11 is a cross-sectional view taken along line AA of FIG. 1 of the upper side of a battery module according to another embodiment of the present invention. FIG. 12 is a drawing showing a second pressure applied to a battery module according to another embodiment of the present invention.

[0152] Referring to FIG. 11, the first adhesive member (501) can be applied to the entire area corresponding to the top plate (212) of the case (200), as well as the area corresponding to the flexible cover (300). Since the first venting portion (2121) provided on the top plate (212) can be formed to be smaller in size than the second venting portion (301) provided on the flexible cover (300), the surface of the top plate (212) excluding the first venting portion (2121) may have a larger area than the surface of the flexible cover (300) excluding the second venting portion (301). The first adhesive member (501) can be applied to the surface of the top plate (212) protruding from the flexible cover (300), as well as to the portion facing the flexible cover (300).

[0153] When referring to the portion marked B in FIGS. 11 and 12, if the hard cover (400) is ruptured and the first region (410) is separated from the second region (420), at least a portion of the separated first region (410) can be bonded to the top plate (212) by the first adhesive member (501). Thus, the separated first region (410) can be fixed in position on the top plate (212) without being shaken by external pressure, etc.

[0154] When a thermal event occurs, if the separated first region (410) shakes in a vertical or horizontal direction due to external pressure, etc., stability may be reduced, and it may be difficult to prevent external venting gas from entering the interior. According to the above embodiment of the present invention, the position of the separated first region (410) is fixed, so the stability of the battery module (10) can be maintained even after the hard cover (400) is ruptured. In addition, according to the above embodiment of the present invention, the separated first region (410) can more reliably cover the first venting part (2121), so that external venting gas can be effectively prevented from entering the interior.

[0155] FIG. 13 is a cross-sectional view of the upper side of a battery module according to another embodiment of the present invention, cut along line AA of FIG. 1.

[0156] Referring to the portion marked D in FIG. 13, a fracture portion (V) may be formed between the first region (410) and the second region (420) of the hard cover (400). The fracture portion (V) may be formed on the upper surface of the hard cover (400). The fracture portion (V) may be formed along the boundary surface between the first region (410) and the second region (420). For example, the fracture portion (V) may include a fracture line or a preliminary cut line configured to be fractured by explosive pressure. For example, the fracture portion (V) may have a closed-loop shape. For example, the fracture portion (V) may be formed with a locally thinner thickness than the surrounding area of ​​the hard cover (400) to facilitate fracture.

[0157] When a first pressure (P1) and / or a second pressure (P2) is applied to the hard cover (400), the first region (410) may be separated from the second region (420). At this time, if the fracture surface of the first region (410) is uneven, damage may be inflicted on the flexible cover (300) and other parts within the battery module (10) may also be damaged.

[0158] According to the above embodiment of the present invention, a fracture portion (V) can be provided in the hard cover (400) to induce the fracture portion (V) to fracture, and the fracture surface of the fractured first region (410) can be formed more evenly. Accordingly, damage to other parts within the battery module (10), including the flexible cover (300), can be minimized.

[0159] FIG. 14 is a cross-sectional view of the upper side of a battery module according to another embodiment of the present invention, cut along line AA of FIG. 1. FIG. 15 is a drawing showing a second pressure applied to a battery module according to another embodiment of the present invention.

[0160] The size of the second venting section (301) may be formed to be larger than the size of the first area (410). The diameter (L3) of the second venting section (301) may be larger than the diameter (L1) of the first area (410). Here, the diameter (L1) of the first area (410) and the diameter (L3) of the second venting section (301) may be diameters measured in the width direction or diameters measured in the length direction.

[0161] The first region (410), separated from the second region (420), can be placed on the top plate (212) by passing through the second venting section (301). When the separated first region (410) falls downward, if it is caught by the flexible cover (300) surrounding the second venting section (301), the first region (410) may not be placed horizontally with the top plate (212). In this case, external venting gas, etc., may not be completely blocked.

[0162] According to the above embodiment of the present invention, when the separated first region (410) falls downward, it can be placed on the top plate (212) without getting caught or bumped by the flexible cover (300) surrounding the second venting part (301). Therefore, the separated first region (410) can more reliably cover the first venting part (2121), so that external venting gas can be effectively prevented from flowing into the interior.

[0163] FIG. 16 is a schematic perspective view of a battery pack including a battery module according to one embodiment of the present invention.

[0164] Referring to FIG. 16, a battery pack (1) according to one embodiment of the present invention may include one or more battery modules (10) according to one embodiment of the present invention as described above. The battery pack (1) according to the present invention may further include a pack case (2) for accommodating components such as a Battery Management System (BMS) for integrated control of charging and discharging of one or more battery modules, a current sensor, a fuse, etc., as described above.

[0165] FIG. 17 is a schematic perspective view of a vehicle including a battery pack according to one embodiment of the present invention.

[0166] Referring to FIG. 17, a vehicle (M) according to one embodiment of the present invention may include one or more battery packs (1) or battery modules (10) according to one embodiment of the present invention. The vehicle (M) according to the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle (M) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (M) operates by receiving power from the battery pack (1) to the battery module (10) according to one embodiment of the present invention.

[0167] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A cell stack comprising a plurality of battery cells; A case for accommodating the cell stack, comprising a top plate having at least one first venting portion configured to discharge venting gas; A flexible cover disposed on the above case and having at least one second venting part formed at a position corresponding to the first venting part and configured to discharge venting gas; and A battery module comprising a hard cover disposed on the flexible cover and divided into a plurality of regions having different thicknesses.

2. In Paragraph 1, A battery module characterized in that the hard cover is divided into a first region formed with a first thickness corresponding to the first venting portion and a second region formed with a second thickness thicker than the first thickness, which is the remaining region excluding the first region.

3. In Paragraph 2, A battery module characterized in that the lower surface of the hard cover, which is the surface facing the flexible cover, has the first region recessed in an upward direction compared to the second region.

4. In Paragraph 3, A battery module characterized in that the lower surface of the hard cover is subjected to pressure of venting gas exiting in the outer direction of the battery module, limited to the first area.

5. In Paragraph 2, A battery module characterized in that the upper surface, which is the opposite side of the surface facing the flexible cover in the hard cover, is formed as a flat surface.

6. In Paragraph 5, A battery module characterized in that the upper surface of the hard cover above is subjected to pressure of venting gas entering from the outside inward direction of the battery module in the first region and the second region.

7. In Paragraph 2, A battery module characterized in that the contact area between the venting gas exiting from the inside of the battery module in an outward direction and the hard cover is narrower than the contact area between the venting gas entering from the outside of the battery module in an inward direction and the hard cover.

8. In Paragraph 2, A battery module characterized in that the surface pressure acting on the hard cover by the venting gas exiting from the inside of the battery module in an outward direction is higher than the surface pressure acting on the hard cover by the venting gas entering from the outside of the battery module in an inward direction.

9. In Paragraph 2, A battery module characterized in that the first region is configured to be separated from the second region when a thermal event occurs in the battery cell.

10. In Paragraph 9, A battery module characterized in that the first region separated from the second region is configured to cover at least a portion of the first venting portion when moved downward.

11. In Paragraph 2, The first region is configured to be separated from the second region by external pressure, and A battery module characterized in that the first region separated from the second region is configured to cover at least a portion of the first venting portion when moved downward.

12. In Paragraph 2, A battery module characterized in that the size of the first region is formed to be larger than the size of the first venting portion.

13. In Paragraph 2, A battery module characterized in that at least one of the hard cover and the flexible cover comprises a mica material.

14. In Paragraph 2, A battery module characterized in that the hard cover is made of a material having a higher hardness than the flexible cover.

15. In Paragraph 2, The above flexible cover is, A battery module characterized by being configured to cover at least three sides of the above case, thereby protecting the battery cells within the battery module from external venting gas of the battery module.

16. In Paragraph 2, The above flexible cover is, An upper cover that covers the upper side of the above case and has the second venting portion formed thereon, A left cover extending from the upper cover so as to be foldable and covering the left side of the case, and A battery module characterized by having a right cover that extends from the upper cover so as to be foldable and covers the right side of the case.

17. In Paragraph 1, A first adhesive member disposed between the above case and the above flexible cover, and A battery module characterized by further comprising a second adhesive member disposed between the flexible cover and the hard cover.

18. In Paragraph 1, A battery module characterized in that the size of the second venting portion is formed to be larger than the size of the first venting portion.

19. A battery pack characterized by including at least one battery module described in any one of claims 1 to 18.

20. An automobile characterized by including at least one battery module described in any one of claims 1 to 18.

Images