Battery module top cover structure

Abstract

The present invention provides a battery module structure including a battery cell stack, a housing that is open at the top and contains the battery cell stack, and a top cover that covers the top of the housing, wherein the top cover includes a first layer made of a rigid body, a second layer made of a flexible body and stacked on the first layer, a vent hole that passes vertically through the first layer, and a non-circular slit that passes vertically through the second layer, and the first layer and the second layer are fixed to each other along at least a portion of a frame section.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-01333143 dated October 17, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module structure with improved gas vent function. [Background technology]

[0003] Secondary batteries, which are easily applicable to a wide range of products and have electrical properties such as high energy density, are commonly used not only in portable devices but also in electric vehicles or hybrid vehicles powered by electrical sources, power storage devices, etc. These secondary batteries are attracting attention as a new energy source because they not only have the primary advantage of dramatically reducing the use of fossil fuels, but also because they are environmentally friendly and improve energy efficiency by not producing any by-products from energy use.

[0004] While small mobile devices use one or two or three battery cells per device, medium to large devices such as automobiles require high output and large capacity, so medium to large battery modules, which electrically connect multiple battery cells, are used.

[0005] It is desirable to manufacture medium- to large-sized battery modules with small size and weight if possible, so prismatic batteries and pouch-shaped batteries, which can be stacked with high density and have low weight relative to capacity, are mainly used as battery cells for medium- to large-sized battery modules.

[0006] 1 and 2 are a perspective view and an exploded perspective view, respectively, showing the structure of a typical battery module. Referring to these drawings, a typical battery module may include a battery cell stack 4 formed by stacking a plurality of battery cells 41, a housing 3 that is open at the top and accommodates the battery cell stack 4, and a top cover 1 that covers the top of the housing 3. The housing 3 may include a U-frame 31 that is open at the top and front and rear, and a pair of end plates 32 that cover the front and rear of the U-frame 31, respectively.

[0007] Meanwhile, the battery cells 41 may ignite or experience thermal runaway due to a short circuit or impact. Thermal runaway may occur when the battery cells 41 generate heat energy and gas. The heat energy and gas may increase the pressure resistance of the housing 3, potentially causing a chain reaction of fires in adjacent battery cells and resulting in an explosion of the battery module (M). Therefore, it is necessary to exhaust the heat energy and gas to the outside of the housing 3 to prevent the battery module from exploding and to suppress further fires from the battery cells 41.

[0008] Furthermore, a battery pack can be formed by connecting a plurality of battery modules in series or parallel via terminals exposed on the end plates 32. The thermal energy and gas are primarily released through the exposed terminals, which can lead to a chain reaction of fires and even larger explosions in adjacent battery modules. Therefore, it is preferable to prevent heat transfer between these battery modules.

[0009] Therefore, a battery module structure is required that can efficiently reduce the internal pressure and temperature of the housing by discharging the thermal energy and gas generated by the thermal runaway to the outside, but that does not allow this venting action to occur toward other adjacent battery modules and that can also block the inflow of thermal energy and gas generated from other adjacent battery modules into the housing. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention was conceived in light of the background of the prior art described above, and aims to provide a battery module structure that can efficiently discharge thermal energy and gas and can adjust the internal pressure and temperature so as not to become excessive.

[0011] It is yet another object of the present invention to provide a battery module structure in which the vent direction is guided so as not to be directed toward other adjacent battery modules.

[0012] Another technical objective of the present invention is to provide a battery module structure that can prevent thermal energy and gas generated from other battery modules from flowing into the housing, thereby preventing chain reactions of fire.

[0013] Yet another technical object of the present invention is to provide a battery module structure that can be manufactured with only minimal structural changes so that existing battery module production processes and production facilities can be used to the maximum extent possible while achieving all of the above-mentioned objects.

[0014] The technical object of the present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages of the present invention can be understood from the following description and can be more clearly understood from the examples of the present invention. Furthermore, it can be easily understood that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0015] In order to solve the above problems, the present invention provides a battery module structure including a battery cell stack, a housing that is open at the top and contains the battery cell stack, and a top cover that covers the top of the housing, wherein the top cover includes a first layer made of a rigid body, a second layer made of a flexible body and stacked on the first layer, a vent hole that passes vertically through the first layer, and a non-circular slit that passes vertically through the second layer, and the first layer and the second layer are fixed to each other along at least a portion of a frame section.

[0016] The first layer may be made of a heat-resistant and fire-resistant material.

[0017] The second layer may be made of a heat and fire resistant material.

[0018] The slits may include a first type slit provided in the area where the vent hole is provided on the plane. The first type slit, together with the vent hole, can function as a valve that allows gas to be discharged faster than the gas to flow in.

[0019] The slits may include a second type of slit provided in an area on the plane where the vent holes are not provided, and the second type of slit, together with the vent holes, can function as a valve that allows gas to be discharged but not to enter.

[0020] The slits may include a third type slit provided across the area where the vent holes are provided and the area where the vent holes are not provided on a plane. The third type slit can have an intermediate function between the first type slit and the second type slit.

[0021] The second layer may include two or more of the slits that meet or intersect each other at a single point. When two or more of the slits meet or intersect each other, the expansion of the slits may be made easier.

[0022] The top cover may include a fixing member that fixes the first layer and the second layer to each other on the frame, and the fixing member may define a boundary of an area within which the second layer can expand.

[0023] The fixing member may include a first fixing member that penetrates the first layer and the second layer.

[0024] The first fixing member may include a bolt and nut or a rivet.

[0025] The first fastening member may include a push-in rivet including a head portion and a snap portion, and the snap portion of the push-in rivet may be compressed to pass through the first layer and the second layer and then released.

[0026] The fixing member may include a second fixing member that presses the second layer toward the first layer.

[0027] The second fixing member may include a horizontal portion extending horizontally and a vertical portion extending vertically.

[0028] The second layer may include an overhang portion formed so that one end thereof protrudes compared to one end of the first layer.

[0029] The overhanging portion may be folded so that its end faces downward and pressed horizontally inward by the vertical portion, in which case the horizontal portion presses the top surface of the second layer toward the first layer, and the vertical portion presses the overhanging portion toward the outer wall of the housing, thereby sealing the inner region of the frame portion of the second layer.

[0030] The first layer may include a plate layer joined to the housing and a heat insulating layer made of a heat insulating material.

[0031] The heat insulating layer may be provided between the plate layer and the second layer, or may be provided by being laminated on the bottom surface of the plate layer.

[0032] A plurality of the battery modules may be connected in series and / or parallel to form a battery pack in order to increase the charge / discharge capacity and / or power.

[0033] The battery pack may include a vent passage and a vent device for discharging heat energy and gases discharged upward from the battery module.

[0034] The vent device may be configured to rupture when the internal pressure of the battery pack (P) reaches a predetermined level, thereby allowing the thermal energy and gas to be discharged.

[0035] The battery pack can be installed inside a vehicle as a power source for the vehicle. [Effects of the Invention]

[0036] The present invention can provide a battery module structure that allows thermal energy and gas to be efficiently discharged through vent holes and slits, and can adjust the internal pressure and temperature to prevent them from becoming excessive.

[0037] The present invention also provides a battery module structure that can guide the direction of the vent so that the air is discharged through a top cover provided above, rather than toward other adjacent battery modules.

[0038] Another advantage of the present invention is that the provision of a heat insulating layer can block the inflow of thermal energy generated from other battery modules, and the formation of a stacked structure can prevent the inflow of gas, thereby providing a battery module structure that can block chain fires.

[0039] The advantage of the present invention is that it provides a battery module structure that can be manufactured using existing battery module production processes and production equipment, simply by replacing the existing top cover with a top cover of a new structure.

[0040] In addition to the above, the present invention can achieve various other effects, which will be explained in each embodiment, or explanations of effects that can be easily inferred by ordinary engineers will be omitted. [Brief explanation of the drawings]

[0041] [Figure 1] FIG. 1 is a perspective view showing the structure of a general battery module. [Figure 2] FIG. 1 is an exploded perspective view showing the structure of a general battery module. [Figure 3] FIG. 2 is an exploded perspective view showing a layered structure of a top cover according to an embodiment of the present invention. [Figure 4] FIG. 10 is an exploded perspective view showing a layered structure of a top cover according to a first modified example of the present invention, which includes slits that intersect with each other. [Figure 5] 5A and 5B are schematic diagrams showing the gas exhaust action of a first type slit according to an embodiment of the present invention. [Figure 6] 5A and 5B are schematic diagrams illustrating the gas inflow prevention effect of a first type slit according to an embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram showing the gas exhausting action of the second type slit according to the embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram showing the gas inflow prevention effect of the second type slit according to the embodiment of the present invention. [Figure 9] 1 is a perspective view showing a structure of a battery module according to an embodiment of the present invention; [Figure 10] 1 is an exploded perspective view showing the structure of a battery module according to an embodiment of the present invention; [Figure 11] 10 is a cross-sectional view of the battery module taken along line A in FIG. 9. [Figure 12]FIG. 10 is a perspective view showing the structure of a battery module including an overhang portion according to a second modified example of the present invention. [Figure 13] FIG. 10 is an exploded perspective view showing the structure of a battery module including an overhang portion according to a second modified example of the present invention. [Figure 14] 13 is a cross-sectional view taken along line A' of the battery module in FIG. 12. [Figure 15] FIG. 10 is an exploded perspective view showing a layered structure of a top cover according to a third modified example of the present invention, which is provided with a heat insulating layer. [Figure 16] FIG. 10 is an exploded perspective view showing the structure of a battery module according to a third modified example of the present invention, which is provided with a heat insulating layer. [Figure 17] FIG. 17 is a cross-sectional view of the battery module of FIG. [Figure 18] 1 is a perspective view showing a battery pack including a battery module according to an embodiment of the present invention; [Figure 19] 1 is a perspective view showing a vehicle including a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0042] The above-mentioned objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the technical concept of the present invention. In describing the present invention, if a detailed description of known technologies relating to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0043] Although terms such as "first" and "second" are used to indicate various components, it is understood that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0044] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0045] Hereinafter, when an arbitrary structure is arranged "on top (or bottom)" of a component or "above (or below)" a component, it means that the arbitrary structure is not only arranged in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure arranged above (or below) the component.

[0046] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0047] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as "comprise" or "include" in this application should not be interpreted as including all of the components or steps described in the specification, but should be interpreted as meaning that some of the components or steps may not be included, or that additional components or steps may be included.

[0048] In the entire specification, "A and / or B" means A, B or A and B unless otherwise specified, and "C to D" means C or more and D or less unless otherwise specified.

[0049] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0050] 1 and 2 are perspective and exploded perspective views, respectively, showing the structure of a typical battery module. Referring to these drawings, a typical battery module may include a battery cell stack 4 formed by stacking a plurality of battery cells 41, a housing 3 that is open at the top and accommodates the battery cell stack 4, and a top cover 1 that covers the top of the housing 3. The housing 3 may include a U-frame 31 that is open at the top and front and rear, and end plates 32 that cover the front and rear of the U-frame 31.

[0051] The battery cells 41 may ignite and generate thermal energy and gas. If the thermal energy and gas are not released to the outside, heat may spread to other adjacent battery cells, causing a chain reaction of fires, and there is a risk that the battery module may explode due to an increase in the internal pressure and temperature of the housing 3. Furthermore, the thermal energy and gas are likely to be released into the exposed portions of the terminals on the end plates 32, which may cause heat to spread to other adjacent battery modules, resulting in a risk of a chain reaction of fires.

[0052] The present invention relates to a battery module having a top cover structure that can guide the discharge of thermal energy and gas to the outside in a specific direction and block the inflow of thermal energy and gas from the outside.

[0053] Specifically, the present invention provides a battery module structure including a battery cell stack, a housing that is open at the top and contains the battery cell stack, and a top cover that covers the top of the housing, wherein the top cover includes a first layer made of a rigid body, a second layer made of a flexible body and stacked on the first layer, a vent hole that passes vertically through the first layer, and a non-circular slit that passes vertically through the second layer, and the first layer and the second layer are fixed to each other along at least a portion of a frame section.

[0054] The present invention is not necessarily limited to battery modules in which battery cells are installed, but can be applied to any object that has a housing that contains contents and that needs to promote the exhaust of gas from inside the housing and prevent the inflow of gas from outside the housing.

[0055] Furthermore, although it is stated throughout this specification that the housing can be open at the top and that the top cover can cover the top of the housing, it will be easily understood from the following explanation that the principles for solving the problems of the present invention can be applied regardless of the direction in which the housing is opened.

[0056] 3 and 4 are exploded perspective views showing a layered structure of a top cover according to one embodiment of the present invention, and an exploded perspective view showing a layered structure of a top cover according to a first modified example of the present invention including intersecting slits, respectively. Referring to these drawings, the top cover 1 can be formed into a structure in which a first layer and a second layer are stacked.

[0057] The first layer 11 may be formed of a rigid body. The first layer 11 may also be made of a heat-resistant and fire-resistant material. For example, the first layer 11 may be made of a metal material. That is, the first layer 11 may preferably be made of a material having sufficient rigidity to prevent deformation despite the thermal energy and gas discharged from the battery module and loads applied by other members due to the discharge of the thermal energy and gas.

[0058] The first layer 11 may have a vent hole 111 penetrating it from top to bottom. One or more vent holes 111 may be provided. The shape, area, and position of the vent hole 111 are not limited as long as the first layer 11 has sufficient rigidity to prevent deformation even in the portions where the vent holes 111 are not provided.

[0059] The second layer 12 may be formed of a flexible material. The second layer 12 may also be made of a heat-resistant and fire-resistant material. For example, the second layer 12 may be made of a heat-resistant and fire-resistant synthetic resin film material. That is, the second layer 12 may preferably be made of a material that is not destroyed by the thermal energy and gas emitted from the battery module, but that can undergo a certain amount of deformation as intended.

[0060] The second layer 12 may have a non-circular slit 121 that penetrates the second layer 12 from top to bottom. The shape of the slit 121 may vary as long as it is not circular. For example, the slit 121 may be formed in the shape of a line segment extending in any direction. One or more slits 121 may be formed.

[0061] In one embodiment of the present invention, the slits 121 may not intersect with each other. By not intersecting with each other, the slits 121 may minimize unwanted deformation.

[0062] In one embodiment of the present invention, the slits 121 may all extend in the same direction. For example, the slits 121 may extend in the length direction and be spaced apart from each other in the length direction and width direction, forming a lattice pattern.

[0063] In the first modification, the second layer 12 may include two or more slits 121 that intersect or cross each other. For example, the slits 121 may be formed in a "+" shape, with one extending in the length direction and one extending in the width direction crossing each other. In this case, the crossing of the slits 121 makes it easier for the area where the slits 121 are provided to expand.

[0064] However, the shape, length and position of the slits 121 are not limited to any particular shape, length and position, as long as they provide the second layer 12 with sufficient rigidity to prevent breakage.

[0065] The first layer 11 and the second layer 12 may be fixed to each other along at least a portion of a frame portion. The frame portion refers to an annular virtual area located on a plane of the top cover 1, and including at least one vent hole 111 and one slit 121 inside its inner periphery. In other words, the first layer 11 and the second layer 12 may be fixed to each other along at least a portion of an area surrounding at least one vent hole 111 and one slit 121 on a plane. The frame portion may be determined to be plural. Preferably, the frame portion may be determined to be one that includes all of the vent holes 111 and all of the slits 121 in order to maximize the inner area of ​​the frame portion.

[0066] In the following description of the gas exhausting and gas inflow preventing functions of a top cover according to one embodiment of the present invention with reference to the drawings, P1 or P1' refers to the internal pressure of the housing, P2 or P2' refers to the external pressure of the housing, and △P or △P' refers to the difference between P1 and P2 or the difference between P1' and P2', respectively, i.e., the pressure difference between the inside and outside of the housing.

[0067] The slits 121 may include a first type slit 121a provided in the area where the vent hole is provided on a plane.

[0068] 5 is a schematic diagram illustrating the gas exhaust function of a first-type slit according to one embodiment of the present invention. Referring to this diagram, when thermal runaway occurs, the internal pressure (P2) of the housing 3 may be greater than the external pressure (P1) of the housing 3 due to gas generated within the housing 3. In this case, the bottom surface of the second layer 12 receives a pressure (ΔP) from the inside of the housing 3. The area of ​​the bottom surface of the second layer 12 that receives the pressure (ΔP) may be any area of ​​the bottom surface of the second layer 12 except for the point where the second layer 12 is fixed to the first layer 11. Alternatively, the area of ​​the bottom surface of the second layer 12 that receives the pressure (ΔP) may be any area surrounded by the frame.

[0069] The area of ​​the second layer 12 that is subjected to the pressure (ΔP) may expand upward due to the pressure (ΔP). The larger the area of ​​the area on the bottom surface of the second layer 12 that is subjected to the pressure (ΔP), the greater the force applied to the second layer 12, and therefore the more the second layer 12 may expand.

[0070] As the second layer 12 expands, the first-type slits 121a expand, thereby expanding the passage through which the gas can be discharged. The degree of expansion of the first-type slits 121a is positively correlated with the degree of expansion of the second layer 12 and may also be positively correlated with the area of ​​the region in the second layer 12 subjected to the pressure (ΔP). The first-type slits 121a expand because their perimeter is larger than the maximum perimeter of a closed curve with the same area as the open area of ​​the first-type slits 121a. Among closed curves with the same area, the smallest perimeter, i.e., the largest perimeter, is a circle. Therefore, when the first-type slits 121a expand to their maximum, they ideally expand to a circle. Therefore, the principle for solving the above-described problem can be applied to any closed curve shape other than a circle.

[0071] According to one embodiment of the present invention, when the internal pressure (P2) of the housing 3 is greater than the external pressure (P1) of the housing 3, a large area of ​​the bottom surface of the second layer 12 is subjected to pressure (ΔP), causing the second layer 12 to expand upward, thereby expanding the first-type slit 121a and increasing the gas discharge rate.

[0072] 6 is a schematic diagram illustrating the gas inflow prevention effect of a first-type slit according to an embodiment of the present invention. Referring to this, if thermal runaway occurs in another battery module adjacent to the battery module (M), the external pressure (P1') of the housing 3 may be greater than the internal pressure (P2') of the housing 3 due to the gas discharged from the other battery module. In this case, the upper surface of the second layer 12 receives a pressure (ΔP') from outside the housing 3. The pressure (ΔP') may cause a portion of the second layer 12 to expand downward.

[0073] In this case, the area on the top surface of the second layer 12 that expands downward under the influence of the pressure (ΔP') may be the area where the vent hole 111 is provided on a plane. This is because the downward displacement of the area on the plane of the second layer 12 where the vent hole 111 is not provided is restricted by the first layer 11 made of a rigid body that is laminated below. That is, in this case, the area around the vent hole 111 acts as a frame, and only the area inside the vent hole 111 can expand downward under the influence of the pressure (ΔP'), so the degree of expansion of the second layer 12 may be less than in the case of FIG. 5.

[0074] As described above, the degree to which the first-type slit 121a expands is positively correlated with the degree to which the second layer 12 expands, so when gas flows in as in FIG. 6, the degree to which the first-type slit 121a expands is significantly less than when gas is discharged as in FIG. 5, and therefore the gas inflow path may also be even smaller.

[0075] According to one embodiment of the present invention, when the external pressure (P1') of the housing 3 is greater than the internal pressure (P2') of the housing 3, a small area of ​​the upper surface of the second layer 12 corresponding to the vent hole 111 receives pressure (△P') and expands downward. At this time, the area of ​​the second layer 12 that expands as described above is significantly smaller than the area of ​​the second layer 12 that expands when the gas is discharged, so the degree of expansion of the first type slit 121a may also be significantly less than when the gas is discharged. Therefore, it may be significantly more difficult for gas to flow in through the top cover 1 than for gas to be discharged through the top cover 1.

[0076] 3 and 4, the slits 121 may include second type slits 121b provided in areas where the vent holes 111 are not provided on a plan view.

[0077] 7 is a schematic diagram showing the gas discharge action of the second-type slit 121b according to one embodiment of the present invention. Referring to this, in the case of the second-type slit 121b, the expansion action of the second-type slit 121b when discharging gas is similar to that of the first-type slit 121a as shown in FIG. 5, and therefore a description thereof will be omitted.

[0078] 8 is a schematic diagram showing the gas inflow prevention effect of the second type slit according to one embodiment of the present invention. Unlike the first type slit 121a, the second type slit 121b may be attached to the first layer 11 when subjected to a downward pressure (ΔP′) from the outside, but the second type slit 121b is not located above the area where the vent hole 111 is provided, so the inflow of gas itself can be blocked.

[0079] That is, according to one embodiment of the present invention, when the external pressure (P1') of the housing 3 is greater than the internal pressure (P2') of the housing 3, the portion of the second layer 12 corresponding to the area where the vent hole 111 is not provided is pressurized and adheres to the first layer, thereby sealing the second-type slit 121b, and since the second-type slit 121b is not provided in the portion corresponding to the area where the vent hole 111 is provided, the inflow of gas into the housing 3 through the second-type slit 121b can be blocked. In this case, it can be said that the vent hole 111 and the second-type slit 121b both function as a kind of one-way valve.

[0080] The first type slit 121a has an advantage that the position of the vent hole 111 corresponds to the position of the first type slit 121a, allowing for quick gas discharge. The second type slit 121b has an advantage that the second type slit 121b is provided in a location where the vent hole 111 is not provided, thereby sealing the device and completely blocking the inflow of gas when the external pressure is higher than the internal pressure.

[0081] The slits 121 may include a third-type slit extending across the area where the vent holes 111 are provided and the area where the vent holes 111 are not provided. From the above description, it can be easily inferred that the gas discharge function and gas inflow prevention function of the third-type slit are a combination of the functions of the first-type slits 121a and the second-type slits 121b. According to an embodiment of the present invention, the second layer 12 preferably includes an appropriate combination of at least one of the first-type slits 121a, the second-type slits 121b, and the third-type slits. For example, if the slits 121 consist only of the second-type slits 121b, the top cover 1 operates as a complete one-way valve. This may result in negative pressure being generated inside the housing 3 as the internal temperature of the housing 3 drops after thermal runaway ends, resulting in additional load being applied to the housing 3.

[0082] 9 and 10 are a perspective view and an exploded perspective view, respectively, showing the structure of a battery module according to an embodiment of the present invention, and Fig. 11 is a cross-sectional view of the battery module taken along line A in Fig. 9. Referring to these drawings, the first layer 11 and the second layer 12 may be fixed to each other on the frame by a fixing member 2. The fixing member 2 can be anything as long as it can fix the first layer 11 and the second layer 12 to each other.

[0083] The fixing member 2 may include a first fixing member 21. One or more first fixing members 21 may be provided.

[0084] The first fixing member 21 may simultaneously penetrate the first layer 11 and the second layer 12. In this case, the first layer 11 and the second layer 12 may be provided with a first fixing hole 112 and a second fixing hole 122, respectively, through which the first fixing member 21 penetrates.

[0085] The first fixing member 21 may have a hook portion that can limit downward movement of the first layer 11 and upward movement of the second layer 12. For example, the first fixing member 21 may include a bolt and nut or a rivet.

[0086] The first fixing member 21 may be a push-in rivet. In this case, the first fixing member 21 may include a head portion 211 and a snap portion 22. The first fixing member 21 may be compressed by the snap portion 22 being obliquely pressed from the inner circumference of the first fixing hole 112 and the second fixing hole 122, and may be further decompressed inside the housing 3 after passing through the first fixing hole 112 and the second fixing hole 122, thereby positioning the head portion 211 above the second layer 12 and the snap portion 22 below the first layer 11, thereby fixing the first layer 11 and the second layer 12 to each other.

[0087] However, the first fixing member 21 may be anything as long as it penetrates the first layer 11 and the second layer 12 simultaneously so as to fix the first layer 11 and the second layer 12 to each other.

[0088] The fixing member 2 may include a second fixing member. One or more second fixing members 22 may be provided.

[0089] The second fixing member 22 may pressurize the second layer 12 toward the first layer 11. The second fixing member 22 may be provided over a longer section on the frame portion than the first fixing member 21. For example, the second fixing member 22 may be provided to extend in the horizontal direction on the frame portion.

[0090] The second fixing member 22 may include a horizontal portion 221 extending horizontally and a vertical portion 222 extending vertically. The vertical portion 222 may be provided on the outer side compared to the first layer 11.

[0091] The second fixing member 22 may be provided with a third fixing hole 223. In this case, the first fixing member 21 may sequentially penetrate the second fixing member 22, the second layer 12, and the first layer 11 via the third fixing hole 223, the second fixing hole 122, and the first fixing hole 112. When the first fixing member 21 is the push-in rivet, the head portion 211 may press the second fixing member 22 downward, and the snap portion 22 may press the bottom surface of the first layer 11 upward, thereby causing the first layer 11 and the second layer 12 to be tightly fixed to each other via the first fixing member 21 and the second fixing member 22.

[0092] In the event of thermal runaway, only the region within the frame of the second layer 12 can expand due to the fixing member 2. The region on the frame where the fixing member 2 is not provided can function in the same way as the slits 121.

[0093] 12 and 13 are a perspective view and an exploded perspective view, respectively, showing the structure of a battery module according to a second modified example of the present invention including an overhang portion, and Fig. 14 is a cross-sectional view taken along line A' of the battery module of Fig. 12. Referring to these drawings, the second layer 12 may include an overhang portion 123 formed such that one end thereof protrudes more than one end of the first layer 11.

[0094] The overhang portion 123 may be folded so that its end faces downward, surrounding the end of the first layer 11. In this case, the overhang portion 123 may be pressed horizontally inward by the vertical portion 222. When the frame portion is formed along the end of the first layer 11, the overhang portion 123 is pressed after being folded downward as described above, and is thereby tightly attached to the outer wall of the housing 3, thereby improving the tightness of the frame portion.

[0095] 15 and 16 are respectively an exploded perspective view showing the layered structure of a top cover having a heat insulating layer according to a third modified example of the present invention and an exploded perspective view showing the structure of a battery module, and Fig. 17 is a cross-sectional view of the battery module of Fig. 16. Referring to these drawings, the first layer 11 may include a plate layer 11P joined to the housing 3 and a heat insulating layer 11I made of a heat insulating material.

[0096] The plate layer 11P may be made of a metal material.

[0097] The plate layer 11P may be joined to the upper end of the side wall of the housing 3. The joining may be by welding.

[0098] The insulating layer 11I may be laminated on the upper surface of the plate layer 11P, that is, interposed between the first layer 11 and the second layer 12, or may be laminated on the bottom surface of the first layer 11.

[0099] By providing the heat insulating layer 11I, it is possible to prevent the inflow of thermal energy conducted from the outside of the housing 3 to the inside of the housing 3.

[0100] The gas inflow prevention effect described above can block thermal energy diffusing from the outside of the housing 3 to the inside of the housing 3, and the heat insulation effect described above can block thermal energy conducting from the outside of the housing 3 to the inside of the housing 3. This can prevent the battery module (M) from catching fire due to the influence of thermal runaway of other battery modules.

[0101] That is, according to one embodiment of the present invention, the multi-layer structure of the first layer 11 and the second layer 12, in which the vent holes 111 and the slits 121 are respectively provided and which are fixed to each other on the frame portion by the fixing member 2, can facilitate the discharge of gas due to thermal runaway of the battery module (M) and can prevent gas and diffused heat due to thermal runaway of other battery modules from flowing into the battery module (M). Furthermore, by providing the insulating layer 11I, it is possible to prevent conductive heat due to thermal runaway of other battery modules from flowing into the battery module (M).

[0102] 18 and 19 are perspective views showing a battery pack including a battery module according to an embodiment of the present invention and a vehicle including the battery pack, respectively. Referring to these drawings, a plurality of battery modules (M) can be connected in series and / or parallel to form a battery pack (P) to increase the charge / discharge capacity and / or power. The battery pack (P) can also be installed inside the vehicle (V) as a power source for the vehicle (V).

[0103] The battery pack (P) may include a vent passage and a vent device for discharging thermal energy and gases discharged upward from the battery module (M). The vent device may rupture when the internal pressure of the battery pack (P) exceeds a predetermined level, thereby allowing the thermal energy and gases to be discharged. The reduction or blocking of gas inflow into the battery module according to the present invention may be even more significant in a situation where the internal pressure of the battery pack (P) is increasing before the vent device ruptures.

[0104] The general structure and manufacturing method of the battery pack (P) and the vehicle (V), including those described above, are well known to those of ordinary skill in the art and will not be described in detail herein.

[0105] It should be understood that the above-described embodiments are illustrative in all respects and are not limiting, and the scope of the present invention is defined by the following claims rather than the above detailed description. All modifications and variations within the meaning and scope of the following claims, as well as equivalent concepts, should be construed as being included within the scope of the present invention.

[0106] Although the present invention has been described above with reference to illustrative drawings, the present invention is not limited to the embodiments and drawings disclosed in this specification, and various modifications may be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described in the above description of the embodiments of the present invention, it is natural that the effects that can be predicted by the configuration should also be recognized. [Explanation of symbols]

[0107] 1 Top cover 11 1st layer 11P Plate Layer 11I Insulation layer 111 Vent hole 112 1st fixing hole 12 2nd layer 121 Slit 121a Type 1 slit 121b Type 2 slit 122 2nd fixing hole 123 Overhang 2 Fixing member 21 First fixing member 211 Head 22 Snap part 22 Second fixing member 221 Horizontal section 222 Vertical section 223 3rd fixing hole 3. Housing 31 U-frame 32 End plate 4 Battery cell stack 41 Battery Cells M Battery Module P Battery pack V Automobile X Length direction / Front-to-back direction Y width direction / horizontal direction Z height direction / up and down direction

Claims

1. a battery cell stack; and a housing that is open at the top and that houses the battery cell stack; a top cover that covers an upper portion of the housing; A battery module comprising: The top cover is a first layer formed of a rigid body; a second layer formed of a flexible material and laminated on the first layer; a vent hole provided so as to penetrate the first layer in a vertical direction; a non-circular slit extending vertically through the second layer; Including, the first layer and the second layer are fixed to each other along at least a portion of the frame; Battery module.

2. The first layer is made of a heat-resistant and fire-resistant material. The battery module according to claim 1 .

3. the second layer is made of a heat-resistant and fire-resistant material; The battery module according to claim 1 .

4. The slit is A first type slit is provided in the area where the vent hole is provided on a plane. The battery module according to claim 1 .

5. The slit is A second type slit is provided in a region where the vent hole is not provided on a plane. The battery module according to claim 1 .

6. The slit is a third type slit provided across a region where the vent hole is provided and a region where the vent hole is not provided on a plane; The battery module according to claim 1 .

7. two or more of said slits meeting or crossing each other at a single point, The battery module according to claim 1 .

8. The top cover is a fixing member that fixes the first layer and the second layer to each other on the frame portion; The battery module according to claim 1 .

9. The fixing member is a first fixing member penetrating the first layer and the second layer; The battery module according to claim 8 .

10. the first fixing member includes a bolt and a nut or a rivet; The battery module according to claim 9 .

11. The first fixing member includes a push-in rivet including a head portion and a snap portion. The battery module according to claim 10.

12. The fixing member is a second fixing member that presses the second layer toward the first layer; The battery module according to claim 8 .

13. the second fixing member includes a horizontal portion extending horizontally and a vertical portion extending vertically, the second layer includes an overhang portion having one end portion projecting from one end portion of the first layer, The overhang portion is folded so that its end faces downward and is pressed horizontally inward by the vertical portion. The battery module according to claim 12.

14. The first layer is a plate layer joined to the housing; a heat insulating layer made of a heat insulating material; Including, The battery module according to claim 1 .

15. The heat insulating layer is interposed between the plate layer and the second layer. The battery module according to claim 14.

16. The heat insulating layer is laminated on the bottom surface of the plate layer. The battery module according to claim 14.

17. A battery module comprising the battery module according to any one of claims 1 to 16. Battery pack.

18. a vent passage through which gas and heat energy discharged from the battery module can pass; a vent device that ruptures when the internal pressure of the battery pack reaches a predetermined level or higher, thereby discharging the gas and heat energy to the outside of the battery pack; Including, 18. The battery pack according to claim 17.

19. 18. A battery pack comprising: car.

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