Structure of the top cover of the battery module

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 filed on October 17, 2022, and all the contents disclosed in the document of the Korean Patent Application are incorporated herein by reference.

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

Background Art

[0003] Secondary batteries, which are highly applicable to a wide range of products and have electrical characteristics such as high energy density, are commonly used not only in portable devices but also in electric vehicles or hybrid vehicles driven by an electric drive source, power storage devices, etc. These secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also attract attention as a new energy source that is environmentally friendly and improves energy efficiency because they do not generate any by-products from the use of energy.

[0004] One or two or three battery cells are used per device in small mobile devices, while medium to large-sized devices such as automobiles require a large capacity with high output. Therefore, medium to large-sized battery modules in which a large number of battery cells are electrically connected are used.

[0005] Medium to large-sized battery modules are preferably manufactured with a small size and weight if possible, and thus, square batteries, pouch-type batteries, etc. that can be stacked with a high degree of integration and have a low weight-to-capacity ratio are mainly used as the battery cells of medium to large-sized battery modules.

[0006] Figures 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 multiple battery cells 41, a housing 3 that is open at the top and houses 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] On the other hand, the battery cell 41 is at risk of igniting due to a short circuit or impact, or of thermal runaway occurring. In the event of thermal runaway, thermal energy and gas are generated from the battery cell 41. This thermal energy and gas can increase the pressure resistance of the housing 3, potentially causing a chain reaction of ignition in other adjacent battery cells and leading to the explosion of the battery module (M). Therefore, it is necessary to discharge the thermal energy and gas to the outside of the housing 3 to prevent the explosion of the battery module and suppress further ignition of the battery cell 41.

[0008] Furthermore, multiple battery modules can be connected in series or parallel to each other via terminals exposed on the end plate 32 to form a battery pack. The thermal energy and gases are mainly discharged through the exposed terminals, which can cause a chain reaction of ignition in other adjacent battery modules and potentially lead to a larger explosion. Therefore, it is preferable to prevent heat propagation between these battery modules.

[0009] Therefore, a battery module structure is required that can efficiently lower the internal pressure and temperature of the housing by venting the thermal energy and gas generated by the thermal runaway to the outside, but without these venting actions occurring toward other adjacent battery modules, and that can also block the inflow of thermal energy and gas generated by other adjacent battery modules into the housing. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention was conceived against 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 regulate its internal pressure and internal temperature so that they do not become excessive.

[0011] The present invention also aims to provide a battery module structure in which the venting direction is guided so as not to be directed toward other adjacent battery modules.

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

[0013] Another technical challenge of the present invention is to provide a battery module structure that can be manufactured with minimal structural modifications, so as to maximize the use of existing battery module production processes and equipment, in order to achieve all of the above objectives.

[0014] The technical problems of the present invention are not limited to the purposes mentioned above. Other purposes and advantages of the present invention not mentioned can be understood from the following description and will be more clearly understood from the embodiments of the present invention. Furthermore, it will be readily understood that the purposes and advantages of the present invention can be achieved by the means and combinations thereof described in the claims. [Means for solving the problem]

[0015] To solve the above problems, the present invention provides a battery module structure comprising a battery cell stack, a housing that is open at the top and houses the battery cell stack, and a top cover that covers the top of the housing, wherein 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, vent holes provided so as to penetrate the first layer vertically, and non-circular slits that penetrate the second layer vertically, and the first layer and the second layer are fixed to each other along at least a portion of the frame.

[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-resistant and fire-resistant material.

[0018] The slit may include a first type of slit provided on a plane in the region where the vent hole is provided. The first type of slit, together with the vent hole, can function as a valve in which the gas discharge rate is faster than the gas inflow rate.

[0019] The aforementioned slit may include a second type of slit provided in a region on the plane where the vent hole is not provided. The second type of slit, together with the vent hole, can function as a valve through which gas can be discharged but not into.

[0020] The slit may include a third type of slit that extends across a plane, encompassing both the region where the vent hole is provided and the region where the vent hole is not provided. The third type of slit can perform an intermediate function between the first type of slit and the second type of slit.

[0021] The second layer may include two or more of the slits that intersect or meet at a single point. If two or more of the slits intersect or meet, the expansion of the slits may become even easier.

[0022] The top cover may include a fixing member that fixes the first layer and the second layer on the frame portion to each other. The fixing member may determine the boundary of the region where the second layer can expand.

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

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

[0025] The first fixing member may include a push-in rivet including a head portion and a snap portion. The snap portion of the push-in rivet may be compressed, pass through the first layer and the second layer, and then the compression may be 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 in the horizontal direction and a vertical portion extending in the vertical direction.

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

[0029] The overhang portion may be folded so that its end portion faces downward and may be pressed horizontally inward by the vertical portion. In this case, the horizontal portion presses the upper surface of the second layer toward the first layer, and the vertical portion presses the overhang 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 thermal insulation layer may be interposed between the plate layer and the second layer, or it may be laminated on the bottom surface of the plate layer.

[0032] Multiple battery modules can be connected to each other in series and / or parallel to form a single battery pack in order to increase their charge and discharge capacity and / or power.

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

[0034] The venting device may rupture when the internal pressure of the battery pack (P) exceeds a predetermined level, thereby enabling the release of thermal energy and gas.

[0035] The battery pack can be installed inside the automobile to serve as a power source for the automobile. [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 that can regulate the internal pressure and internal temperature so as not to become excessive.

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

[0038] Another effect of the present invention is that, by providing an insulating layer, the inflow of thermal energy generated from other battery modules is blocked, and by forming a laminated structure, the inflow of gas is prevented, thereby providing a battery module structure that can prevent chain reactions of ignition.

[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 equipment simply by replacing the existing top cover with a top cover of the new structure.

[0040] In addition to the above, the present invention can achieve various other effects, which will be explained in each embodiment, or, in cases where such effects can be easily inferred by an ordinary person, such explanations will be omitted. [Brief explanation of the drawing]

[0041] [Figure 1] This is a perspective view showing the structure of a typical battery module. [Figure 2] This is an exploded perspective view showing the structure of a typical battery module. [Figure 3] This is an exploded perspective view showing the laminated structure of the top cover according to one embodiment of the present invention. [Figure 4] This is an exploded perspective view showing the laminated structure of the top cover according to a first modification of the present invention, which includes mutually intersecting slits. [Figure 5] This is a schematic diagram illustrating the gas discharge operation of a first-type slit according to one embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating the gas inflow prevention function of a first-type slit according to one embodiment of the present invention. [Figure 7] This is a schematic diagram illustrating the gas discharge operation of a second-type slit according to one embodiment of the present invention. [Figure 8] This is a schematic diagram illustrating the gas inflow prevention function of a second type slit according to one embodiment of the present invention. [Figure 9] This is a perspective view showing the structure of a battery module according to one embodiment of the present invention. [Figure 10] This is an exploded perspective view showing the structure of a battery module according to one embodiment of the present invention. [Figure 11] This is a cross-sectional view of the battery module along line A in Figure 9. [Figure 12]This is a perspective view showing the structure of a battery module according to a second modification of the present invention, including an overhang portion. [Figure 13] This is an exploded perspective view showing the structure of a battery module according to a second modification of the present invention, including an overhang portion. [Figure 14] This is a cross-sectional view of the battery module along A' in Figure 12. [Figure 15] This is an exploded perspective view showing the laminated structure of a top cover according to a third modified example of the present invention, which includes an insulating layer. [Figure 16] This is an exploded perspective view showing the structure of a battery module according to a third modification of the present invention, which includes an insulating layer. [Figure 17] Figure 16 is a cross-sectional view of the battery module. [Figure 18] This is a perspective view showing a battery pack including a battery module according to one embodiment of the present invention. [Figure 19] This is a perspective view showing an automobile including a battery pack according to one embodiment of the present invention. [Modes for carrying out the invention]

[0042] The aforementioned objectives, features, and advantages will be described in detail below with reference to the accompanying drawings, so that a person with ordinary skill in the art to which the present invention pertains can easily implement the technical concept of the present invention. In describing the present invention, if a specific description of known technology according 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," "second," etc., are used to indicate various components, these components are not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0044] In the entire specification, unless otherwise stated, each component may be singular or plural.

[0045] In the following, the placement of any configuration "above (or below)" a component or "above (or below)" a component means not only that the configuration is placed in contact with the upper (or lower) surface of the component, but also that other configurations may be interposed between the component and any configuration placed on (or below) it.

[0046] Furthermore, where it is stated that one component is “linked,” “joined,” or “connected” to another component, it should be understood that the components may be directly linked or connected to one another, but may also be “interposed” between each component, or each component may be “linked,” “joined,” or “connected” through other components.

[0047] In this specification, singular expressions include plural expressions unless otherwise explicitly stated in the context. Terms such as “composed of” or “including” in this application should not be interpreted as necessarily including all of the multiple components or steps described in the specification, but rather as including some of the components or steps, or including further components or steps.

[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 greater and D or less unless otherwise specified.

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

[0050] Figures 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 multiple battery cells 41, a housing 3 that is open at the top and houses 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 cell 41 can ignite, generating thermal energy and gas. If this thermal energy and gas are not released to the outside, heat transfer may occur to other adjacent battery cells, potentially causing a chain reaction of ignition. This increases the internal pressure and temperature of the housing 3, posing a risk of the battery module exploding. Furthermore, there is a high possibility that the thermal energy and gas will be released to the exposed terminals on the end plate 32, which could lead to heat transfer to other adjacent battery modules and a risk of a chain reaction of ignition.

[0052] The present invention relates to a battery module as described above, comprising a top cover structure that guides the discharge of thermal energy and gas to the outside in a specific direction and blocks the inflow of thermal energy and gas from the outside.

[0053] Specifically, the present invention provides a battery module structure comprising a battery cell stack, a housing that is open at the top and houses the battery cell stack, and a top cover that covers the top of the housing, wherein the top cover includes a first layer formed of a rigid body, a second layer formed of a flexible body and stacked on the first layer, vent holes provided to penetrate the first layer vertically, and non-circular slits that penetrate the second layer vertically, and the first and second layers are fixed to each other along at least a portion of the frame.

[0054] The present invention is not necessarily limited to battery modules containing battery cells, but can be applied to any device that has a housing for containing contents, where it is necessary to promote the discharge of gas from inside the housing and prevent the inflow of gas from outside the housing.

[0055] Furthermore, despite the expression throughout this specification that the housing may be open at the top and the top cover may cover the top of the housing, it will be readily apparent from the following description that the principle for solving the problems of the present invention is applicable regardless of the direction in which the housing is open.

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

[0057] The first layer 11 can be formed from a rigid body. Furthermore, the first layer 11 may be made of a heat-resistant and fire-resistant material. For example, the first layer 11 may be made of a metallic material. That is, preferably, the first layer 11 may be made of a material with sufficient rigidity to prevent deformation despite the heat energy and gases discharged from the battery module, and the loads applied to other components by the discharge of such heat energy and gases.

[0058] The first layer 11 may be provided with vent holes 111 that penetrate it vertically. One or more vent holes 111 may be provided. The shape, area, and position of the vent holes 111 are not limited as long as the first layer 11 has sufficient rigidity so that deformation does not occur even in the parts where the vent holes 111 are not provided.

[0059] The second layer 12 can be formed from a flexible material. Alternatively, the second layer may 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, preferably, the second layer 12 may be made of a material that does not break down due to the thermal energy and gases emitted from the battery module, but is capable of undergoing a certain deformation as intended.

[0060] The second layer 12 may be provided with a non-circular slit 121 that penetrates it vertically. The shape of the slit 121 can vary, as long as it is not circular. For example, the slit 121 may be in the shape of a line segment extending in either direction. One or more slits 121 may be provided.

[0061] In one embodiment of the present invention, the slits 121 do not have to intersect with each other. By not intersecting the slits 121, the slits 121 can minimize the normal, unnecessary deformation.

[0062] Furthermore, in one embodiment of the present invention, the slits 121 may all extend along the same direction. For example, the slits 121 may extend in the longitudinal direction and be arranged in a grid pattern, spaced apart from each other in the longitudinal and width directions.

[0063] In the first modified example, 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 like a "+" sign, with one extending in the length direction and the other extending in the width direction intersecting each other. In this case, the intersection of the slits 121 makes the portion where the slits 121 are provided more likely to expand.

[0064] However, the shape, length, and position of the slit 121 are not limited to any other reason, as long as they provide sufficient rigidity to prevent the second layer 12 from breaking.

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

[0066] In describing below, with reference to the drawings, the gas discharge function and gas inflow prevention function of the top cover according to one embodiment of the present invention, P1 or P1' means the internal pressure of the housing, and P2 or P2' means the external pressure of the housing, and △P or △P' means the difference between P1 and P2 or the difference between P1' and P2', respectively, that is, the pressure difference between the inside and outside of the housing.

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

[0068] Figure 5 is a schematic diagram showing the gas discharge operation of a first-type slit according to one embodiment of the present invention. Referring to this, if 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 the gas generated inside the housing 3. In this case, the bottom surface of the second layer 12 is subjected to pressure (ΔP) from inside the housing 3. At this time, the area on the bottom surface of the second layer 12 that is subjected to the pressure (ΔP) may be any area on 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 on the bottom surface of the second layer 12 that is subjected to the pressure (ΔP) may be any area enclosed by the frame.

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

[0070] As the second layer 12 expands, the first type slit 121a expands, and the passage through which the gas can be discharged can expand. The degree to which the first type slit 121a expands has a positive correlation with the degree to which the second layer 12 expands, and may also have a positive correlation with the area of ​​the region in the second layer 12 that receives the pressure (△P). The reason that the first type slit 121a expands is that its circumference is larger than the maximum circumference of a closed curve with the same area as its open area. Among closed curves with the same area, the one with the smallest circumference, that is, the one with the largest area among closed curves with the same circumference, is circular. Therefore, when the first type slit 121a expands to its maximum extent, it can ideally expand until it becomes circular. Thus, the principle for solving the above-mentioned problems can be applied to any shape of closed curve, not just circular, for the first type slit 121a.

[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), thereby causing the second layer 12 to expand upward, which in turn expands the first type slit 121a and can increase the gas discharge rate.

[0072] Figure 6 is a schematic diagram showing the gas inflow prevention function of a first-type slit according to one embodiment of the present invention. Referring to this, if thermal runaway occurs in another battery module adjacent to the battery module (M), the gas discharged from the other battery module may cause the external pressure (P1') of the housing 3 to be greater than the internal pressure (P2') of the housing 3. In this case, the upper surface of the second layer 12 is subjected to pressure (△P') from outside the housing 3. Due to this pressure (△P'), a part of the second layer 12 may expand downward.

[0073] In this case, the region on the upper surface of the second layer 12 that expands downward due to the influence of the pressure (△P') may be the region on the plane where the vent hole 111 is provided. This is because the region on the plane of the second layer 12 where the vent hole 111 is not provided is restricted from downward displacement by the first layer 11, which is made of a rigid body stacked below it. In other words, in this case, the area around the vent hole 111 acts with the frame, and only the region inside the vent hole 111 can expand downward due to the influence of the pressure (△P'), so the degree of expansion of the second layer 12 may be less than in the case of Figure 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. Therefore, as shown in Figure 6, when gas flows in, the degree to which the first type slit 121a expands is significantly less than when gas is discharged, as shown in Figure 5. Thus, the gas inflow passage may 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 narrow area of ​​the upper surface of the second layer 12 corresponding to the vent hole 111 is subjected to the 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 during gas discharge. Therefore, the degree of expansion of the first type slit 121a may also be significantly less than during gas discharge. Consequently, gas inflow through the top cover 1 may be significantly more difficult than gas discharge through the top cover 1.

[0076] Referring further to Figures 3 and 4, the slit 121 may include a second type of slit 121b provided in a region on the plane where the vent hole 111 is not provided.

[0077] Figure 7 is a schematic diagram showing the gas discharge operation of a second-type slit according to one embodiment of the present invention. Referring to this, in the case of the second-type slit 121b, the expansion operation of the second-type slit 121b during gas discharge is similar to that of the first-type slit 121a as shown in Figure 5, so a detailed explanation is omitted.

[0078] Figure 8 is a schematic diagram showing the gas inflow prevention function of a second type slit according to one embodiment of the present invention. Referring to this, unlike the first type slit 121a, in the case of the second type slit 121b, when subjected to downward pressure (△P') from the outside, the second type slit 121b may be attached to the first layer 11, and since the second type slit 121b is not placed in the area where the vent hole 111 is provided, the gas inflow itself can be blocked.

[0079] In other words, 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. Since the portion of the second layer 12 corresponding to the area where the vent hole 111 is provided does not have a second type slit 121b, the inflow of gas into the housing 3 through the second type slit 121b is completely blocked. In this case, both the vent hole 111 and the second type slit 121b can be said to function as a kind of one-way valve.

[0080] In the case of the first type slit 121a, the position of the vent hole 111 corresponds to the position of the first type slit 121a, which has the advantage of enabling good and fast discharge of gas. In the case of the second type slit 121b, the second type slit 121b is provided where the vent hole 111 is not provided, which has the advantage of being able to seal off and completely block the inflow of gas when the external pressure is higher than the internal pressure.

[0081] The slit 121 may include a third type of slit that extends across a region on a plane where the vent hole 111 is provided and a region where the vent hole 111 is not provided. From the above description, it can be easily inferred that the gas discharge and gas inflow prevention functions of the third type of slit are a combination of the functions of the first type of slit 121a and the second type of slit 121b, as described above. The second layer 12 according to one embodiment of the present invention preferably consists of an appropriate combination of at least one type of slit 121a, the second type of slit 121b, and the third type of slit. For example, if the slit 121 consists only of the second type of slit 121b, the top cover 1 acts like a complete one-way valve, which may result in the formation of negative pressure inside the housing 3 as the internal temperature of the housing 3 decreases after thermal runaway has ended, thereby adding further load to the housing 3.

[0082] Figures 9 and 10 are perspective views and exploded perspective views, respectively, showing the structure of a battery module according to one embodiment of the present invention, and Figure 11 is a cross-sectional view along line A of the battery module in Figure 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 that 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. The first fixing member 21 may be provided as one or more units.

[0084] The first fixing member 21 may penetrate both the first layer 11 and the second layer 12 simultaneously. 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 include a retaining portion that can restrict 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 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 configured such that the snap portion 22 is compressed by oblique pressure from the inner circumference of the first fixing hole 112 and the second fixing hole 122, and after passing through the first fixing hole 112 and the second fixing hole 122, it is further decompressed inside the housing 3, 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 can be anything that penetrates the first layer 11 and the second layer 12 simultaneously so that the first layer 11 and the second layer 12 can be fixed to each other.

[0088] The fixing member 2 may include a second fixing member. The second fixing member 22 may be provided in one or more units.

[0089] The second fixing member 22 may press the second layer 12 toward the first layer 11. The second fixing member 22 may be provided over a longer section on the frame than the first fixing member 21. For example, the second fixing member 22 may be provided extending horizontally on the frame.

[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 outside 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 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. If the first fixing member 21 is a push-in rivet, the head portion 211 presses the second fixing member 22 downward, and the snap portion 22 presses the bottom surface of the first layer 11 upward, thereby fixing the first layer 11 and the second layer 12 in close contact with each other via the first fixing member 21 and the second fixing member 22.

[0092] The fixing member 2 allows the second layer 12 to expand only within the frame portion during thermal runaway. The area on the frame portion where the fixing member 2 is not provided can function similarly to the slit 121.

[0093] Figures 12 and 13 are perspective views and exploded perspective views, respectively, showing the structure of a battery module according to a second modification of the present invention including an overhang portion, and Figure 14 is a cross-sectional view along A' of the battery module in Figure 12. Referring to these drawings, the second layer 12 may include an overhang portion 123, one end of which is formed to protrude compared to one end of the first layer 11.

[0094] The overhang portion 123 may be folded around the end of the first layer 11 so that its end points downward. In this case, the overhang portion 123 can be pressed inward horizontally by the vertical portion 222. When the frame portion is formed along the end of the first layer 11, as described above, the degree of contact of the frame portion can be improved by pressing the overhang portion 123 after it has been folded downward and is in close contact with the outer wall of the housing 3.

[0095] Figures 15 and 16 are exploded perspective views showing the laminated structure of a top cover according to a third modification of the present invention, which includes an insulating layer, and an exploded perspective view showing the structure of a battery module, respectively. Figure 17 is a cross-sectional view of the battery module in Figure 16. Referring to these drawings, the first layer 11 may include a plate layer 11P that is joined to the housing 3 and an insulating layer 11I made of an 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 done by welding.

[0098] The heat 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 it may be laminated on the bottom surface of the first layer 11.

[0099] The provision of the aforementioned heat insulating layer 11I prevents the inflow of thermal energy from the outside of the housing 3 into the inside of the housing 3.

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

[0101] In other words, according to one embodiment of the present invention, the multilayer structure of the first layer 11 and the second layer 12, each provided with the vent holes 111 and the slits 121 and fixed to each other on the frame by the fixing member 2, allows for smooth discharge of gas due to thermal runaway of the battery module (M), prevents gas and diffusing heat from other battery modules from entering the battery module (M), and by providing the heat insulating layer 11I, it is also possible to prevent conductive heat from other battery modules from entering the battery module (M) from thermal runaway.

[0102] Figures 18 and 19 are perspective views showing a battery pack including a battery module and an automobile including the battery pack, respectively, according to one embodiment of the present invention. Referring to these drawings, multiple battery modules (M) can be connected to each other in series and / or parallel to form a single battery pack (P) in order to increase their charge / discharge capacity and / or power. Furthermore, the battery pack (P) can be installed inside an automobile (V) as a power source for the automobile (V).

[0103] The battery pack (P) may include a vent passage and a vent device to discharge thermal energy and gases discharged upward from the battery module (M). The vent device may enable the discharge of thermal energy and gases by rupturing when the internal pressure of the battery pack (P) exceeds a predetermined level. The gas inflow reduction or blocking effect of the present invention would be even more meaningful in situations where the internal pressure of the battery pack (P) is increasing before the vent device ruptures.

[0104] Including those described above, the general structure and manufacturing methods of the battery pack (P) and the automobile (V) are known to the average engineer and will not be described in detail elsewhere in this specification.

[0105] The embodiments described above should be understood to be illustrative and not limiting in all respects, and the scope of the present invention is indicated more by the claims described below than by the detailed description above. The meaning and scope of the claims described below, as well as any modifications and deformable forms conceived from their equivalent concepts, should be interpreted as being included within the scope of the present invention.

[0106] As described above, the present invention has been explained with reference to the illustrative drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and it is natural that various modifications can be made by an ordinary person 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 and explained while embodiments of the present invention have been described above, it is natural that predictable effects from such configurations should also be acknowledged. [Explanation of symbols]

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

Claims

1. Battery cell stack and The top is open and the housing accommodates the stack of battery cells, A top cover that covers the upper part of the housing, A battery module including, The aforementioned top cover is The first layer is formed of a rigid body, A second layer formed of a flexible material and laminated on the first layer, A vent hole is provided so as to penetrate the first layer vertically, A non-circular slit that penetrates the second layer vertically, Includes, 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 aforementioned slit is A first type of slit is provided on a plane in the region where the vent hole is provided, The battery module according to claim 1.

5. The aforementioned slit is A second type of slit is provided on the plane in an area where the vent holes are not provided, The battery module according to claim 1.

6. The aforementioned slit is A third type of slit is provided on a plane, extending across the region where the vent holes are provided and the region where the vent holes are not provided. The battery module according to claim 1.

7. Including two or more of the slits that intersect or cross each other at a single point, The battery module according to claim 1.

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

9. The aforementioned fixing member is Including a first fixing member that penetrates 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 rivet. The battery module according to claim 9.

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

12. The aforementioned fixing member is The second fixing member includes a second fixing member that pressurizes 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, one end of which is formed to protrude compared to one end of the first layer. The overhang portion is folded so that its end faces downward and is pressed inward horizontally by the vertical portion. The battery module according to claim 12.

14. The first layer is, A plate layer joined to the housing, An insulating layer made of an insulating material, including, The battery module according to claim 1.

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

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

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

18. A vent passage through which gas and thermal energy discharged from the battery module can pass, A venting device that ruptures when the internal pressure of the battery pack exceeds a predetermined level, thereby releasing the gas and thermal energy to the outside of the battery pack, including, The battery pack according to claim 17.

19. Includes the battery pack described in claim 17, car.

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