Top cover structure of battery module

Abstract

The invention provides a structure of a battery module. The structure comprises a battery cell stack; a case having an open upper end and accommodating the battery cell stack; and a top cover for covering the top end of the housing, in which the top cover comprises: a first layer formed of a rigid body; a second layer formed of a flexible body and stacked on the first layer; a discharge hole penetrating the first layer in a vertical direction; and a slit penetrating the second layer in the vertical direction and being non-circular, and the first layer and the second layer being fixed to each other along at least a partial section of the edge portion.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0133143, filed on October 17, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery module having an improved gas emission function. Background Art

[0003] Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are widely used not only in portable devices but also in electric vehicles or hybrid vehicles driven by an electric drive source and power storage devices. These secondary batteries are attracting attention as new energy sources for improving eco-friendliness and energy efficiency, not only because they have the main advantage of being able to significantly reduce the use of fossil fuels but also because they do not generate any by-products due to energy use.

[0004] While one, two, or three battery cells are used for each device in small mobile devices, medium and large-sized devices such as vehicles require high output and large capacity. Therefore, medium and large-sized battery modules in which a plurality of battery cells are electrically connected are used.

[0005] Since it is desired to manufacture medium and large-sized battery modules with the smallest possible size and weight, rectangular batteries and pouch-type batteries that can be stacked with high integration and have a small weight-to-capacity ratio are mainly used as battery cells for medium and large-sized battery modules.

[0006] Figure 1 And Figure 2 are a perspective view and an exploded perspective view illustrating the structure of a general battery module. Referring to Figure 1 and Figure 2 , a general battery module may include: a battery cell laminate 4 manufactured by stacking a plurality of battery cells 41; a case 3 having an open upper end and accommodating the battery cell laminate 4l; and a top cover 1 covering the upper end of the case 3. The case 3 may include: a U-shaped frame 31 having an open upper end and front and rear ends; and a pair of end plates 32 respectively covering the front and rear ends of the U-shaped frame 31.

[0007] In addition, due to short circuit or impact, the battery cell 41 has a risk of catching fire or thermal runaway. In the case of thermal runaway, heat energy and gas are generated from the battery cell 41. The heat energy and gas may increase the internal pressure of the case 3 and cause a series of fires in other adjacent battery cells, resulting in an explosion of the battery module M. Therefore, it is necessary to prevent the explosion of the battery module and suppress additional ignition of the battery cell 41 by discharging the heat energy and gas to the outside of the case 3.

[0008] In addition, multiple battery modules can be connected in series or in parallel with each other through terminals exposed by the end plate 32 to form a battery pack. Heat energy and gas are mainly discharged through the exposed areas of the terminals, which may cause series ignition in other adjacent battery modules, leading to a larger explosion. Therefore, it is also desirable to prevent heat transfer between battery modules.

[0009] Therefore, a battery module structure is needed that can effectively reduce the internal pressure and internal temperature of the housing by discharging heat energy and gas generated due to thermal runaway, prevent discharge towards other adjacent battery modules, and prevent heat energy and gas generated from other adjacent battery modules from entering the housing. Summary of the Invention

[0010] Technical Problem

[0011] The present invention was invented in the context of the above-mentioned prior art, and the object of the present invention is to provide a structure of a battery module that can effectively discharge heat energy and gas to control its internal pressure and internal temperature, thereby preventing excessive internal pressure and internal temperature.

[0012] Another object of the present invention is to provide a structure of a battery module that can guide the discharge so as not to face other adjacent battery modules.

[0013] Yet another object of the present invention is to provide a structure of a battery module that can prevent heat energy and gas generated from other battery modules from entering the housing, thereby preventing series ignition.

[0014] Yet another object of the present invention is to provide a structure of a battery module that can be manufactured with minimal structural changes, so that traditional battery module production processes and production equipment can be utilized to the greatest extent when achieving the above objects.

[0015] The technical problems to be solved by the present invention are not limited to the above objects, and other objects and advantages of the present invention not described can be understood through the following description and will be more clearly understood through the examples of the present invention. Additionally, it is obvious that the objects and advantages of the present invention can be embodied by the means and combinations pointed out in the claims.

[0016] Technical Solution

[0017] To solve the above problems, the present invention provides a battery module, which includes: a battery cell laminate; a housing having an open upper end and accommodating the battery cell laminate; and a top cover covering the upper end of the housing, wherein the top cover includes: a first layer having a rigid main body; a second layer having a flexible main body and stacked on the first layer; a discharge hole penetrating the first layer in a vertical direction; and a non-circular slit penetrating the second layer in the vertical direction, and at least one section of the edges of the first layer and the second layer are fixed to each other.

[0018] The first layer may include a heat-resistant and fire-resistant material.

[0019] The second layer may include a heat-resistant and fire-resistant material.

[0020] The non-circular slit may include a first type of slit provided at a portion of the second layer corresponding to the portion of the first layer where the discharge hole is provided. Together with the exhaust hole, the first type of slit can be used as a valve with a gas outflow rate higher than the gas inflow rate.

[0021] The non-circular slit may include a second type of slit provided at a portion of the second layer corresponding to the portion of the first layer where the discharge hole is not provided. Together with the exhaust hole, the second type of slit can be used as a valve that allows gas to flow out but does not allow gas to flow in.

[0022] The non-circular slit may include a third type of slit provided at a portion of the second layer corresponding to the portion of the first layer extending across the regions where the discharge hole is provided and where the discharge hole is not provided. The third type of slit can provide an intermediate function between the first type of slit and the second type of slit.

[0023] The second layer may include two or more non-circular slits that cross or intersect at a point. When two or more non-circular slits cross or intersect each other, the expansion of the slits can be promoted.

[0024] The top cover may include a fixing member that couples the first layer and the second layer to each other at the portion of their edges. The fixing member can determine the boundary of the expansion region of the second layer.

[0025] The fixing member may include a first fixing member that penetrates the first layer and the second layer.

[0026] The first fixing member includes a bolt and a nut or a rivet.

[0027] The first fixing member may include a push rivet having a head and a snap portion. The snap portion of the push rivet may be compressed to pass through the first layer and the second layer and then decompressed.

[0028] The fixing member includes a second fixing member that presses the second layer against the first layer.

[0029] The second fixing member may include: a horizontal portion that extends in the horizontal direction; and a vertical portion that extends in the vertical direction, and.

[0030] The second layer may include an overhang having an end that protrudes from one end of the first layer.

[0031] One end of the overhang may be folded downward and pressed inward in the horizontal direction by the vertical portion. In this case, the horizontal portion presses the upper surface of the second layer against the first layer, and the vertical portion presses the overhang against the outer sidewall of the housing, thereby sealing the area inside the edge of the second layer.

[0032] The first layer may include: a plate layer joined to the housing; and an insulating layer including an insulating material.

[0033] The insulating layer may be disposed between the plate layer and the second layer, or may be stacked on the bottom surface of the plate layer.

[0034] A plurality of battery modules may be interconnected in series and / or in parallel to form a battery pack in order to increase the charge and discharge capacity and / or power.

[0035] The battery pack may further include a discharge device and a discharge channel through which heat energy and gas discharged from the battery module in the upward direction pass.

[0036] When the internal pressure of the battery pack P exceeds a predetermined level, the discharge device may rupture to discharge heat energy and gas to the outside of the battery pack.

[0037] The battery pack may be built into a vehicle as its power source.

[0038] Advantageous Effects

[0039] The present invention provides a structure of a battery module in which heat energy and gas can be effectively discharged through discharge holes and slits to prevent excessive internal pressure and internal temperature.

[0040] The present invention also provides a structure for a battery module that can guide discharge through a top cover provided at the upper end instead of toward other adjacent battery modules.

[0041] Another effect of the present invention is that it can provide a structure of a battery module, wherein the inflow of heat energy generated from other battery modules is blocked by having an insulating layer, and the inflow of gas is prevented by a stacking structure, thereby preventing series ignition of the battery modules.

[0042] The advantage of the present invention is that it can provide a structure of a battery module, which can be manufactured by simply replacing a conventional top cover with a top cover having a novel structure using conventional battery module production processes and production equipment.

[0043] In addition, the present invention can have various other effects, and descriptions thereof will be given in each embodiment, or descriptions of effects that can be easily inferred by those skilled in the art will be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 and Figure 2 are a perspective view and an exploded perspective view respectively illustrating the structure of a general battery module.

[0045] Figure 3 and Figure 4 are an exploded perspective view respectively illustrating the stacking structure of a top cover according to an embodiment of the present invention and an exploded perspective view illustrating the stacking structure of a top cover having slits intersecting each other according to a first modification example of the present invention.

[0046] Figure 5 and Figure 6 are schematic diagrams respectively illustrating the gas discharge operation and the gas inflow prevention operation of a first type of slit according to an embodiment of the present invention.

[0047] Figure 7 and Figure 8 are schematic diagrams respectively illustrating the gas discharge operation and the gas inflow prevention operation of a second type of slit according to an embodiment of the present invention.

[0048] Figure 9 and Figure 10 are a perspective view and an exploded perspective view respectively illustrating the structure of a battery module according to an embodiment of the present invention, and Figure 11 is Figure 9 a cross-sectional view taken along line A of the battery module shown.

[0049] Figure 12 and Figure 13 are a perspective view and an exploded perspective view respectively illustrating the structure of a battery module including a hanging portion according to a second modification example of the present invention, and Figure 14 is Figure 12 a cross-sectional view taken along line A' of the battery module shown.

[0050] Figure 15 andFigure 16 is an exploded perspective view illustrating a stacked structure of a top cover having an insulating layer and a structure of a battery module according to a third modification example of the present invention, and Figure 17 illustrates Figure 16 a cross-sectional view of the battery module shown in

[0051] Figure 18 and Figure 19 are perspective views illustrating a battery pack including the battery module and a vehicle including the battery pack according to an embodiment of the present invention, respectively.

[0052] [Description of Reference Numerals]

[0053] 1: Top cover

[0054] 11: First layer

[0055] 11P: Plate layer

[0056] 11I: Insulating layer

[0057] 111: Discharge hole

[0058] 112: First fixing hole

[0059] 12: Second layer

[0060] 121: Slit

[0061] 121a: First type of slit

[0062] 121b: Second type of slit

[0063] 122: Second fixing hole

[0064] 123: Overhang

[0065] 2: Fixing member

[0066] 21: First fixing member

[0067] 211: Head

[0068] 22: Latching portion

[0069] 22: Second fixing member

[0070] 221: Horizontal portion

[0071] 222: Vertical portion

[0072] 223: Third fixing hole

[0073] 3: Housing

[0074] 31: U-shaped frame

[0075] 32: End plate

[0076] 4: Battery cell laminate

[0077] 41: Battery cell

[0078] M: Battery module

[0079] P: Battery pack

[0080] V: Vehicle

[0081] X: Longitudinal / forward / backward direction

[0082] Y: Width direction / left - right direction

[0083] Z: Height direction / up - down direction Detailed implementation manners

[0084] In the following, the above - mentioned objects, features, and advantages will be described in detail with reference to the accompanying drawings, so that those skilled in the art will be able to implement the technical concept of the present invention. When determining that the detailed description of the prior art related to the present invention will unnecessarily obscure the key points of the present invention, its detailed description will be omitted. In the following, the preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0085] Although "first", "second", etc. are used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another, and unless otherwise clearly stated, the first element may also be the second element.

[0086] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0087] In the following, "arranging an element at the upper part (or lower part) of an element" or "arranging an element at the top (or bottom) of an element" not only indicates "arranging the element in contact with the upper surface (or lower surface)", but also indicates "arranging the element above the upper surface (or lower surface) while another element is interposed therebetween".

[0088] In addition, when an element is described as "connected to" another element, "coupled with" another element, or "in contact with" another element, it should be understood that the element may be "directly connected to" another element, "directly coupled with" another element, or "in direct contact with" another element, or the element may be "connected to" another element, "coupled with" another element, or "in contact with" another element while yet another element is interposed therebetween or the element is "connected to" another element, "coupled with" another element, or "in contact with" another element via yet another element.

[0089] Unless the context clearly indicates otherwise, singular expressions used herein include plural expressions. Terms such as "consisting of" or "including" used herein should not be construed as necessarily including all elements or steps described in the specification, but should be construed as not including some elements or steps, or including additional elements or steps.

[0090] In addition, unless the context clearly indicates otherwise, singular expressions used herein include plural expressions. Terms such as "consisting of" or "including" used herein should not be construed as necessarily including all elements or steps described in the specification, and should be construed as not including some elements or steps, or including additional elements or steps.

[0091] Throughout the specification, unless otherwise clearly stated, "A and / or B" refers to A, B, or A and B, and unless otherwise clearly stated, "C to D" refers to from equal to or higher than C to equal to or lower than D.

[0092] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0093] Figure 1 and Figure 2 are a perspective view and an exploded perspective view respectively illustrating the structure of a general battery module. Referring to Figure 1 and Figure 2 , a general battery module may include: a battery cell laminate 4 manufactured by stacking a plurality of battery cells 41; a case 3 having an open upper end and accommodating the battery cell laminate 4; and a top cover 1 covering the open upper end of the case 3. The case 3 may include a U-shaped frame 31 having an open upper end, a front end, and a rear end, and end plates 32 covering the front end and the rear end of the U-shaped frame 31.

[0094] Returning to refer to Figure 1 and Figure 2 , the battery cell 41 may generate heat energy and gas during ignition. When the heat energy and gas are not discharged to the outside, the heat may spread to other adjacent battery cells, resulting in series ignition, and an increase in the internal pressure and internal temperature of the case 3 may cause the battery module to explode. In addition, there is a high possibility that the heat energy and gas are discharged through the terminal exposed portion provided on the end plate 32, and thus there is a risk of heat spreading to other adjacent battery modules, resulting in series ignition.

[0095] The present invention relates to a battery module having a top cover structure that allows heat energy and gas to be discharged to the outside in a specific direction and prevents heat energy and gas from flowing in from the outside.

[0096] Specifically, the present invention provides a structure of a battery module, which includes: a battery cell laminate; a housing having an open upper end and accommodating the battery cell laminate; and a top cover covering the upper end of the housing, wherein the top cover includes: a first layer having a rigid body; a second layer having a flexible body and laminated on the first layer; a discharge hole penetrating the first layer in a vertical direction; and a non-circular slit penetrating the second layer in a vertical direction, and the first layer and the second layer are fixed to each other along at least one section of their edges.

[0097] The present invention is not necessarily limited to a battery module having built-in battery cells, but can be applied to any product having a housing for accommodating an article, the purpose of which is to facilitate the discharge of gas from its interior and prevent the inflow of gas from its exterior.

[0098] In addition, although the description here is that the housing has an open upper end and the top cover covers the upper end of the housing, the principle of the present invention can be applied to any direction in which the housing is open, which will be easily understood from the following description.

[0099] Figure 3 and Figure 4 are an exploded perspective view illustrating a stacked structure of a top cover according to an embodiment of the present invention and an exploded perspective view illustrating a stacked structure of a top cover having slits intersecting each other according to a first modification example of the present invention. Refer to Figure 3 and Figure 4 , the top cover 1 may include a structure in which the first layer and the second layer are stacked.

[0100] The first layer 11 may have a rigid body. In addition, the first layer 11 may include a heat-resistant and fire-resistant material. For example, the first layer 11 may be made of a metal material. That is, preferably, the first layer 11 may be made of a material having sufficient stiffness that does not deform even in the face of heat energy and gas discharged from the battery module and the load applied by other components caused by the discharge of heat energy and gas.

[0101] A discharge hole 111 penetrating the first layer 11 in a vertical direction may be provided at the first layer 11. One or more discharge holes 111 may be provided. The shape, area, and position of the discharge hole 111 are not limited as long as the portion of the first layer 11 where the discharge hole 111 is not provided has sufficient rigidity to prevent deformation.

[0102] The second layer 12 may have a flexible body. In addition, the second layer may include 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, preferably, the second layer 12 may be made of a material that is not damaged by the heat energy and gas discharged from the battery module, but undergoes a certain expected deformation caused by the heat energy and gas.

[0103] A non-circular slit 121 penetrating the second layer 12 in the vertical direction may be provided at the second layer 12. The shape of the slit 121 may vary as long as it is non-circular. For example, the slit 121 may have the shape of a line segment extending in one direction. One or more slits 121 may be provided.

[0104] According to an embodiment of the present invention, the slits 121 may not intersect each other. Since the slits 121 do not intersect each other, unnecessary deformation of the slits 121 can be minimized.

[0105] In addition, according to an 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, be spaced apart from each other in the length and width directions, and may be arranged in a grid form.

[0106] According to the first modification example, the second layer 12 may include two or more slits 121 that cross or intersect each other. For example, the slits 121 may form a '+' shape by the intersection of one slit extending in the length direction and another slit extending in the width direction. In this case, when the slits 121 intersect each other, the portion where the slits 121 are provided may become easily openable.

[0107] However, the shape, length, and position of the slits 121 are not limited as long as the second layer 12 has sufficient rigidity to prevent it from being damaged.

[0108] The first layer 11 and the second layer 12 may be fixed to each other along at least one section of their edges. The edge indicates an annular two-dimensional virtual plane including the top cover 1, within the inner circumference of which at least one discharge hole 111 and at least one slit 121 are provided. That is, the first layer 11 and the second layer 12 may be fixed to each other along at least one section of the area two-dimensionally surrounding one discharge hole 111 and one slit 121. Multiple edges may be selected. Preferably, in order to maximize the inner area of the edge, one edge surrounding all the discharge holes 111 and all the slits 121 may be selected.

[0109] Hereinafter, in the description of the gas discharge operation and the gas inflow prevention operation of the top cover according to an embodiment of the present invention, with reference to the drawings, P1 or P1' refers to the internal pressure of the housing, and P2 or P2' refers to the external pressure of the housing, and ΔP or ΔP' respectively refers to the difference between P1 and P2 or the difference between P1' and P2', that is, the pressure difference between the inside and the outside of the housing.

[0110] The slit 121 may include a first type of slit 121a, and the first type of slit 121a is provided at a portion of the second layer 12 corresponding to a portion of the first layer 11 where the discharge hole 111 is provided.

[0111] Figure 5 FIG. is a schematic diagram illustrating the gas discharge operation of the first type of slit according to an embodiment of the present invention. Refer to Figure 5 , when thermal runaway occurs, due to the gas generated inside the housing 3, the internal pressure P2 of the housing 3 may be greater than the external pressure P1 of the housing 3. In this case, the bottom surface of the second layer 12 may be subjected to the pressure ΔP from the inside of the housing 3. Here, the portion of the bottom surface of the second layer 12 that is subjected to the pressure ΔP may be the entire bottom surface of the second layer 12 except for the portion where the second layer 12 is fixed to the first layer 11. Alternatively, the portion of the bottom surface of the second layer 12 that is subjected to the pressure ΔP may be the entire area surrounded by the edge.

[0112] The portion of the second layer 12 that is subjected to the pressure ΔP may expand in the upward direction due to the pressure ΔP. Since the force applied to the second layer 12 becomes greater as the portion of the bottom surface of the second layer 12 that is subjected to the pressure ΔP becomes larger, the second layer 12 may expand more.

[0113] As the second layer 12 expands, the first type of slit 121a may expand, thereby expanding the channel for discharging gas. Since the degree of expansion of the first type of slit 121a has a positive correlation with the degree of expansion of the second layer 12, there may also be a positive correlation with the portion of the second layer 12 that is subjected to the pressure ΔP. The reason for the expansion of the first type of slit 121a is that the perimeter of the first type of slit 121a may be greater than the maximum perimeter of a closed curve having the same area as the opening area. Since the minimum perimeter among the closed curves having the same area (i.e., the maximum area among the closed curves having the same perimeter) is a circle, the first type of slit 121a may ideally expand to the maximum value until the first type of slit 121a becomes circular. Therefore, even when the first type of slit 121a is not circular but has the shape of any closed curve, the principle for solving the above problems can be applied.

[0114] According to an 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 larger area of the bottom surface of the second layer 12 may be subjected to the pressure ΔP, and thus, the second layer 12 may expand in the upward direction, and as a result, the first type of slit 121a may expand and the gas discharge rate may increase.

[0115] Figure 6 FIG. is a schematic diagram illustrating the operation of preventing gas inflow of the first type of slit according to an embodiment of the present invention. Refer to Figure 6, when thermal runaway occurs in other battery modules adjacent to the battery module M, due to the gas discharged from other battery modules, the external pressure P1' of the housing 3 is higher than the internal pressure P2' of the housing 3. In this case, the upper surface of the second layer 12 may be subjected to the pressure ΔP' from the outside of the housing 3. Due to the pressure ΔP', a part of the second layer 12 can expand in the downward direction.

[0116] Here, the part of the upper surface of the second layer 12 that expands in the downward direction under the influence of the pressure ΔP' can be the part corresponding to the part of the first layer 11 where the discharge hole 111 is provided. This is because the downward displacement of the part of the second layer 12 corresponding to the part of the first layer 11 where the discharge hole 111 is not provided is restricted due to the rigid body stacked below the first layer 11. That is, in this case, since the periphery of the discharge hole 111 acts as an edge, and only the inner part of the discharge hole 111 can expand in the downward direction under the influence of the pressure ΔP', compared with Figure 5 the example of, the degree of expansion of the second layer 12 can be smaller.

[0117] As described above, since the degree of expansion of the first type of slit 121a is positively correlated with the degree of expansion of the second layer 12, compared with the case of gas discharge as shown in Figure 5 shown, in the case of gas inflow as shown in Figure 6 shown, the degree of expansion of the first type of slit 121a is significantly smaller. Therefore, the gas inflow channel will also be smaller.

[0118] According to an embodiment of the present invention, when the external pressure P1' of the housing 3 is higher than the internal pressure P2' of the housing 3, the narrow area of the upper surface of the second layer 12 corresponding to the discharge hole 111 can expand in the downward direction under the pressure ΔP', and since the expansion area of the second layer 12 as described above is significantly smaller than the expansion area of the second layer 12 during gas discharge, the degree of expansion of the first type of slit 121a can also be significantly smaller than that during gas discharge. Therefore, compared with the gas discharge through the top cover 1, the gas inflow through the top cover 1 may be very difficult.

[0119] Returning to refer to Figure 3 and Figure 4 , the slit 121 can include a second type of slit 121b, and the second type of slit 121b is provided at the part of the second layer 12 corresponding to the part of the first layer 11 where the discharge hole 111 is not provided.

[0120] Figure 7 is a schematic diagram illustrating the gas discharge operation of the second type of slit according to an embodiment of the present invention. Referring to Figure 7 , since the expansion operation of the second type of slit 121b during gas discharge is similar to that inFigure 5 The expansion operation of the first type of slit 121a shown is thus omitted from description.

[0121] Figure 8 It is a schematic diagram illustrating the effect of preventing gas inflow of the second type of slit according to an embodiment of the present invention. Refer to Figure 8 , different from the first type of slit 121a, when an external pressure ΔP’ is applied in the downward direction, the second type of slit 121b can be attached to the first layer 11. Since the second type of slit 121b is not provided at a portion of the second layer 12 corresponding to the portion of the first layer 11 where the discharge hole 111 is provided, the inflow of the gas itself can be blocked.

[0122] That is, according to an embodiment of the present invention, when the external pressure P1’ of the housing 3 is higher than the internal pressure P2’ of the housing 3, the portion of the second layer 12 corresponding to the portion of the first layer 11 where the discharge hole 111 is not provided is pressed and attached to the first layer, so that the second type of slit 121b is sealed. Since the second type of slit 121b is not provided at a portion of the second layer 12 corresponding to the portion of the first layer 11 where the discharge hole 111 is provided, the gas can be prevented from flowing into the housing 3 through the second type of slit 121b. In this case, the discharge hole 111 and the second type of slit 121b together function as a kind of check valve.

[0123] The advantage of the first type of slit 121a is that, since the first type of slit 121a is provided at a portion of the second layer 12 corresponding to the portion of the first layer 11 where the discharge hole 111 is provided, faster gas discharge is possible, and the advantage of the second type of slit 121b is that, since the second type of slit 121b is provided at a portion of the second layer 12 corresponding to the portion of the first layer 11 where the discharge hole 111 is not provided, when the external pressure is higher than the internal pressure, the second type of slit 121b can be sealed to completely block the gas inflow.

[0124] The slit 121 may include a third type of slit provided at a portion of the second layer 12 corresponding to a portion of the first layer 11 that extends across a region where the discharge holes 111 are provided and a region where the discharge holes 111 are not provided. It can be easily inferred from the above description that the gas discharge operation and the gas inflow prevention operation of the third type of slit are a combination of the operations of the above-described first type of slit 121a and second type of slit 121b. The second layer 12 according to an embodiment of the present invention preferably includes: one of the first type of slit 121a, the second type of slit 121b, and the third type of slit; and a combination thereof. For example, when the slit 121 includes only the second type of slit 121b, the top cover 1 operates like a complete one-way valve, which causes a negative internal pressure in the housing 3 as the internal temperature of the housing 3 decreases after thermal runaway, thereby resulting in an additional load being applied to the housing 3.

[0125] Figure 9 and Figure 10 are a perspective view and an exploded perspective view illustrating the structure of a battery module according to an embodiment of the present invention, respectively, and Figure 11 is a cross-sectional view taken along line A of the battery module shown Figure 9 . Referring to Figure 9 、 Figure 10 and Figure 11 , the first layer 11 and the second layer 12 can be fixed to each other at the edges by a fixing member 2. The fixing member 2 may include any device capable of fixing the first layer 11 and the second layer 12 to each other.

[0126] The fixing member 2 may include a first fixing member 21. One or more first fixing members 21 may be provided.

[0127] The first fixing member 21 may penetrate through the first layer 11 and the second layer 12 simultaneously. Here, the first layer 11 and the second layer 12 may be provided with first fixing holes 112 and second fixing holes 122 through which the first fixing member 21 penetrates.

[0128] The first fixing member 21 may be provided with a locking portion that restricts the downward movement of the first layer 11 and the upward movement of the second layer 12. For example, the first fixing member 21 may include a bolt and a nut or a rivet.

[0129] The first fixing member 21 may include a push rivet and include a head 211 and a snap portion 22. After compressing the first fixing member 21 by pressing the snap portion 22 obliquely from the inner periphery of the first fixing hole 112 and the second fixing hole 122 to pass through the first fixing hole 112 and the second fixing hole 122, the compression is released inside the housing 3, whereby the head 211 is placed on the second layer 12 and the snap portion 22 is placed below the first layer 11 to fix the first layer 11 and the second layer 12 to each other.

[0130] However, the first fixing member 21 can be any device capable of simultaneously penetrating the first layer 11 and the second layer 12 to fix the first layer 11 and the second layer 12 to each other.

[0131] The fixing member 2 can include a second fixing member 22. One or more second fixing members 22 can be provided.

[0132] The second fixing member 22 can press the second layer 12 toward the first layer 11. The second fixing member 22 can be provided above a longer section than the first fixing member 21 at the edge. For example, the second fixing member 22 can be provided to extend horizontally at the edge.

[0133] The second fixing member 22 can include a horizontal portion 221 extending in the horizontal direction and a vertical portion 222 extending in the vertical direction. The vertical portion 222 can be provided more outward than the first layer 11.

[0134] A third fixing hole 223 can be provided in the second fixing member 22. In this case, the first fixing member 21 can sequentially penetrate the second fixing member 22, the second layer 12, and the first layer 11 through the third fixing hole 223, the second fixing hole 122, and the first fixing hole 112. When the first fixing member 21 is a push-in rivet, the head 211 presses the second fixing member 22 in the downward direction, and the engaging portion 22 presses the bottom surface of the first layer 11 in the upward direction, so that the first layer 11 and the second layer 12 can be fixed in close contact with each other through the first fixing member 21 and the second fixing member 22.

[0135] Due to the fixing member 2, only the portion of the second layer 12 that is more inward than the edge can expand during thermal runaway. The portion of the edge where the fixing member 2 is not provided can function similar to the slit 121.

[0136] Figure 12 and Figure 13 are a perspective view and an exploded perspective view respectively illustrating the structure of a battery module including a hanging portion according to a second modification example of the present invention, and Figure 14 is a cross-sectional view taken along line A' of the battery module shown in Figure 12 . Referring to Figure 12 , Figure 13 and Figure 14 , the second layer 12 can include a hanging portion 123 having one end protruding with respect to one end of the first layer 11.

[0137] One end of the hanging portion 123 can be folded downward and around the end of the first layer 11. Here, one end of the hanging portion can be pressed inward in the horizontal direction by the vertical portion 222. When the edge is formed along the end of the first layer 11, the hanging portion 123 can be folded downward as described above and then pressed to be in close contact with the outer sidewall of the housing 3, thereby increasing the adhesion of the edge.

[0138] Figure 15 and Figure 16 are exploded perspective views respectively illustrating the stacked structure of the top cover having an insulating layer and the structure of the battery module according to the third modification example of the present invention, and Figure 17 illustrate Figure 16 a cross-sectional view of the battery module shown. Referring to Figure 15 、 Figure 16 and Figure 17 the first layer 11 may include a plate layer 11P joined to the housing 3 and an insulating layer 11I including an insulating material.

[0139] The plate layer 11P may include a metallic material.

[0140] The plate layer 11P may be joined to the upper end of the sidewall of the housing 3. The joining may be accomplished by welding.

[0141] The insulating layer 11I may be stacked on the upper surface of the plate layer 11P (i.e., interposed between the first layer 11 and the second layer 12), or stacked on the bottom surface of the first layer 11.

[0142] By providing the insulating layer 11I, heat energy can be prevented from flowing from the outside of the housing 3 into the inside of the housing 3.

[0143] Due to the above-described gas inflow prevention operation, heat energy diffused from the outside of the housing 3 into the inside can be blocked, and also due to the above-described heat insulation operation, heat energy conducted from the outside of the housing 3 into the inside can be blocked. As a result, it is possible to prevent the battery module M from catching fire under the influence of thermal runaway of other battery modules.

[0144] That is, according to an embodiment of the present invention, since the multilayer structure of the first layer 11 and the second layer 12 are respectively provided with discharge holes 111 and slits 121 and are fixed to each other at the edge by the fixing member 2, gas discharge caused by thermal runaway of the battery module M can be promoted, and at the same time, gas and diffused heat caused by thermal runaway of other battery modules can be prevented from flowing into the battery module M. By having the insulating layer 11I, conducted heat caused by thermal runaway of other battery modules can also be prevented from entering the battery module M.

[0145] Figure 18 and Figure 19Stereoscopic views of a battery pack including a battery module and a vehicle including the battery pack according to an embodiment of the present invention are respectively illustrated. Referring to Figure 18 and Figure 19 , a plurality of battery modules M may be connected in series and / or in parallel with each other to form a battery pack P in order to increase the charge and discharge capacity and / or power. In addition, the battery pack P may be built in the vehicle V as a power source of the vehicle V.

[0146] The battery pack P may include an exhaust passage and an exhaust device for exhausting heat energy and gas discharged upward from the battery module M. When the internal pressure of the battery pack P is equal to or greater than a predetermined level, the exhaust device may exhaust heat energy and gas by rupturing. In the case where the internal pressure of the battery pack P increases before the exhaust device ruptures, the effect of reducing or preventing the inflow of gas of the battery module according to the present invention will be more significant.

[0147] Since the general structures and manufacturing methods of the battery pack P and the vehicle V including the above components are known to those skilled in the art, detailed descriptions thereof will not be given herein.

[0148] It should be understood that the described embodiments are illustrative in all aspects and not restrictive, and the scope of the present invention will be indicated by the appended claims rather than the described detailed description. And the meanings and scopes of the claims to be described later and all changes and modifications derived from equivalent concepts should be construed as being included within the scope of the present invention.

[0149] Although the present invention has been described with reference to the exemplary drawings, it is to be understood that the present invention is not limited to the embodiments and the drawings disclosed in the present specification, and those skilled in the art will understand that various modifications are possible without departing from the scope and concept of the present invention. In addition, although the operating effects of the configuration according to the present invention are not explicitly described when describing the embodiments of the present invention, it should be understood that predictable effects will also be recognized by this configuration.

Claims

1. A battery module, the battery module comprising: a battery cell laminate; a housing having an open upper end and accommodating the battery cell laminate; and a top cover covering the upper end of the housing, wherein the top cover includes: a first layer having a rigid body; a second layer having a flexible body and stacked on the first layer; a discharge hole penetrating the first layer in a vertical direction; and a non-circular slit penetrating the second layer in the vertical direction, and the first layer and the second layer are fixed to each other along at least one section of their edges.

2. The battery module according to claim 1, wherein, the first layer includes a heat-resistant and fire-resistant material.

3. The battery module according to claim 1, wherein, the second layer includes a heat-resistant and fire-resistant material.

4. The battery module according to claim 1, wherein, the non-circular slit includes a first type of slit provided at a portion of the second layer corresponding to a portion of the first layer where the discharge hole is provided.

5. The battery module according to claim 1, wherein, the non-circular slit includes a second type of slit provided at a portion of the second layer corresponding to a portion of the first layer where the discharge hole is not provided.

6. The battery module according to claim 1, wherein, the non-circular slit includes a third type of slit provided at a portion of the second layer corresponding to a portion of the first layer extending across an area where the discharge hole is provided and an area where the discharge hole is not provided.

7. The battery module according to claim 1, wherein, the second layer includes two or more non-circular slits intersecting or crossing each other at a point.

8. The battery module according to claim 1, wherein, the top cover includes a fixing member that couples the first layer and the second layer to each other at the portion of their edges.

9. The battery module according to claim 8, wherein, the fixing member includes a first fixing member penetrating the first layer and the second layer.

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

11. The battery module according to claim 10, wherein, the first fixing member includes a push rivet having a head and a snap portion.

12. The battery module according to claim 8, wherein, the fixing member includes a second fixing member pressing the second layer toward the first layer.

13. The battery module according to claim 12, wherein, the second fixing member includes a horizontal portion extending in a horizontal direction and a vertical portion extending in the vertical direction, and the second layer includes a hanging portion having an end protruding with respect to one end of the first layer, wherein the end of the hanging portion is folded downward and pressed inward in the horizontal direction by the vertical portion.

14. The battery module according to claim 1, wherein, the first layer includes: a plate layer that is joined to the housing; and an insulating layer that includes an insulating material.

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

16. The battery module according to claim 14, wherein, the insulating layer is stacked on the bottom surface of the plate layer.

17. A battery pack, the battery pack including the battery module according to any one of claims 1 to 16.

18. The battery pack according to claim 17, the battery pack further includes: a discharge passage that allows gas and thermal energy discharged from the battery module to pass through the discharge passage; and a discharge device that ruptures to discharge the gas and the thermal energy to the outside of the battery pack when the internal pressure of the battery pack is equal to or greater than a predetermined level.

19. A vehicle, the vehicle including the battery pack according to claim 17.

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