Battery module and battery pack including said battery module

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked in one direction, and a module frame that houses the battery cell stack and has an inner surface and an outer surface, wherein at least one venting portion penetrating the inner surface and the outer surface is formed on one surface of the module frame, and a cover layer including a barrier layer and a refractory layer is positioned between the one surface of the module frame in which the venting portion is formed and the battery cell stack.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0089269 dated July 7, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the battery module, and more particularly to a battery module with enhanced safety and a battery pack including the battery module. [Background technology]

[0003] Due to technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. As a result, much research is being conducted on secondary batteries that can meet various requirements.

[0004] Secondary batteries have attracted much attention not only for use in mobile devices such as mobile phones, digital cameras, and notebook computers, but also as energy sources for power plants such as electric bicycles, electric cars, and hybrid electric cars.

[0005] Recently, as secondary batteries are used as energy storage sources, the need for large-capacity secondary battery structures has increased, and the demand for medium- or large-sized modular battery packs in which battery modules in which a number of secondary batteries are connected in series / parallel has been growing. A battery pack is mainly composed of a battery module consisting of at least one battery cell, and is composed of at least one battery module and other components added. Since the battery cells that make up the battery module are composed of secondary batteries that can be charged and discharged, such high-output, large-capacity secondary batteries generate a large amount of heat during the charging and discharging process.

[0006] Fig. 1 is an exploded perspective view of a conventional battery module, and Fig. 2 is a diagram showing how a thermal runaway phenomenon transfers when an internal fire occurs in a conventional battery module.

[0007] Referring to Figures 1 and 2, a conventional battery module 10 includes a battery cell stack 12 in which a plurality of battery cells 11 are stacked, a frame 20 that houses the battery cell stack 12, and end plates 40 formed on the front and rear surfaces of the battery cell stack 12.

[0008] The battery cell stack 12 may be located within a structure sealed by the combination of the frame 20 and the end plates 40. In this case, the frame 20 may have an empty internal space as shown in the AA cross section of Fig. 1, and the battery cells 11 may be stacked in one direction and located in the empty internal space of the frame 20 as shown in Fig. 2.

[0009] On the other hand, since the multiple battery cells 11 are not isolated from one another within the frame 20, but are densely packed in one space, even if a thermal runaway phenomenon occurs in only one of the multiple battery cells 11 inside the frame 20 due to overcharging or other reasons, the thermal runaway phenomenon will rapidly transfer to other adjacent battery cells 11, etc.

[0010] Furthermore, since the multiple battery modules 10 in the battery pack are arranged with at least two end plates 40 facing each other, if heat, gas, flames, etc. generated within the battery module 10 are discharged to the outside of the battery module 10, it may affect the performance and stability of the multiple battery cells 11 in other adjacent battery modules 10.

[0011] Therefore, there is a need to develop a battery module 10 that has improved durability and safety by effectively slowing down the speed of thermal waves when an internal fire occurs in the battery module 10 and allowing the generated heat, gas, or flame to be rapidly discharged to the outside of the battery module 10. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a battery module that prevents the transfer of thermal runaway between battery cells when a fire occurs in the battery module, and a battery pack including the battery module.

[0013] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0014] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked in one direction, and a module frame that houses the battery cell stack and has an inner surface and an outer surface, wherein at least one venting portion penetrating the inner surface and the outer surface is formed on one surface of the module frame, and a cover layer including a barrier layer and a refractory layer is positioned between the one surface of the module frame in which the venting portion is formed and the battery cell stack.

[0015] The venting portion may be formed on an upper surface of the module frame.

[0016] The barrier layer may be located below the refractory layer.

[0017] At least one sub-venting portion may be formed in the refractory layer.

[0018] The barrier layer may cover holes in the sub-venting portion.

[0019] The barrier layer may include a protrusion partially protruding from one surface of the barrier layer, the protrusion being inserted into the sub-venting portion.

[0020] The venting portion and at least a portion of the sub-venting portion may overlap in a longitudinal direction of the battery module.

[0021] The venting portion and at least a portion of the sub-venting portion may overlap in a width direction of the battery module.

[0022] The sub-venting portion or the hole of the venting portion may form an acute angle with one surface of the module frame.

[0023] The refractory layers may include a first refractory layer and a second refractory layer, the first refractory layer being closer to the barrier layer than the second refractory layer.

[0024] The first refractory layer may be formed with at least one first sub-venting portion, and the second refractory layer may be formed with at least one second sub-venting portion.

[0025] The first sub-venting portion and at least a portion of the second sub-venting portion may overlap in a length direction of the battery module.

[0026] The first sub-venting portion and at least a portion of the second sub-venting portion may overlap in a width direction of the battery module.

[0027] The barrier layer may include a material having a melting point of about 300° C. or less.

[0028] The barrier layer may include one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

[0029] The refractory layer may include aluminum, stainless steel (SUS), or clad metal.

[0030] A battery pack according to another embodiment of the present invention includes the above-described battery module. Effect of the Invention

[0031] According to the embodiment, when a fire occurs in the battery module, gas or the like is quickly discharged to the outside of the battery module through the holes in the module frame, thereby preventing continuous thermal runaway in the battery module.

[0032] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is an exploded perspective view of a conventional battery module. [Diagram 2] FIG. 1 is a diagram showing a transition of a thermal runaway phenomenon when an internal fire occurs in a conventional battery module. [Diagram 3] 1 is a perspective view showing a battery module according to an embodiment of the present invention; [Figure 4] FIG. 4 is an exploded perspective view of the battery module shown in FIG. [Diagram 5] 4 is a perspective view of a battery cell included in the battery module of FIG. 3. [Figure 6] 4 is a cross-sectional view taken along the cutting line BB in FIG. 3. [Figure 7] 4 is a cross-sectional view taken along the line CC in FIG. 3. [Figure 8] FIG. 4 is a diagram showing a state in which the battery module shown in FIG. 3 catches fire internally. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may be embodied in various different forms other than those described below, and the scope of the present invention is not limited to the embodiments described herein.

[0035] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0036] In addition, the size and thickness of each component shown in the drawings are arbitrarily enlarged or reduced for convenience of explanation, and it is obvious that the contents of the present invention are not limited to those shown in the drawings. In the following drawings, the thickness of each layer is enlarged to clearly show various layers and regions. In the following drawings, the thickness of some layers and regions is exaggerated for convenience of explanation.

[0037] In addition, when a layer, film, region, plate, or other part is described as being "on" or "above" another part, this should be interpreted as including not only the case where the corresponding layer, film, region, plate, or other part is "directly on" the other part, but also the case where there is another part therebetween. Conversely, when a corresponding layer, film, region, plate, or other part is described as being "directly on" the other part, it can mean that there is no other part therebetween. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction to gravity. Meanwhile, similar to the description of being "on" or "above" another part, the description of being "below" or "below" another part can also be understood by referring to the above content.

[0038] In addition, since the top / bottom surfaces of a particular component can be determined to be different depending on the reference direction, throughout this specification, the terms "top" and "bottom" are defined to mean the two surfaces of the component that face each other along the z-axis.

[0039] Furthermore, throughout the specification, when a part "comprises" a certain element, this does not mean to exclude other elements, but means that the part may further include other elements, unless specifically stated to the contrary.

[0040] Furthermore, throughout the specification, "on a plane" means when the part in question is viewed from above, and "on a cross section" means when the part in question is cut vertically and viewed from the side.

[0041] Hereinafter, a battery module according to an embodiment of the present invention will be described.

[0042] Fig. 3 is a perspective view showing a battery module according to an embodiment of the present invention, Fig. 4 is an exploded perspective view of the battery module according to Fig. 3, and Fig. 5 is a perspective view of a battery cell included in the battery module of Fig. 3.

[0043] 3 and 4, a battery module 100 according to an embodiment of the present invention may include a battery cell stack 120 in which a plurality of battery cells 110 are stacked in one direction, a module frame 200 that houses the battery cell stack 120, a bus bar frame 300 located on a front and / or rear surface of the battery cell stack 120, an end plate 400 that covers the front and / or rear surface of the battery cell stack 120, and bus bars 510, 520 attached to the bus bar frame 300.

[0044] 5, the battery cell 110 may be provided in a pouch type that can maximize the number of cells stacked per unit area. The battery cell 110 provided in a pouch type may be manufactured by housing an electrode assembly including a positive electrode, a negative electrode, and a separator in a cell case 114 made of a laminate sheet, and then heat-sealing a sealing portion of the cell case 114. However, the battery cell 110 does not necessarily have to be provided in a pouch type, and may be provided in a rectangular, cylindrical, or other various shapes as long as a storage capacity required by a device to be installed in the future is achieved.

[0045] The battery cell 110 may include two electrode leads 111, 112. The electrode leads 111, 112 may each have a structure protruding from one end of the cell body 113. Specifically, one end of each of the electrode leads 111, 112 may be located inside the cell case 114 to be electrically connected to a positive electrode or a negative electrode of the electrode assembly, and the other end of each of the electrode leads 111, 112 may be drawn out to the outside of the cell case 114 to be electrically connected to a separate member, for example, the bus bars 510, 520. Meanwhile, while FIG. 4 shows that the positive electrode lead and the negative electrode lead of the battery cell 110 protrude in opposite directions, this is not necessarily the case, and the electrode leads of the battery cell 110 may protrude in the same direction.

[0046] The electrode assembly in the cell casing 114 may be sealed by sealing portions 114sa, 114sb, and 114sc. The sealing portions 114sa, 114sb, and 114sc of the cell casing 114 may be located on both ends 114a and 114b and on one side portion 114c connecting the ends 114a and 114b.

[0047] The cell case 114 generally has a laminate structure of a resin layer / metal thin film layer / resin layer. For example, if the cell case surface is made of an O(oriented)-nylon layer, it tends to slip due to external impact when a large number of battery cells 110, etc. are stacked to form a medium- or large-sized battery module 100. Therefore, in order to prevent slipping due to external impact and to maintain a stable stacked structure of the battery cells 110, etc., an adhesive member such as a pressure-sensitive adhesive such as double-sided tape or a chemical adhesive that bonds by a chemical reaction when bonded can be attached to the surface of the cell case 114 to form the battery cell stack 120.

[0048] The connecting portion 115 may refer to an area extending along the length direction at one end of the cell casing 114 where the sealing portions 114sa, 114sb, and 114sc are not located. A protrusion 110p of the battery cell 110 called a bat-ear may be formed at an end of the connecting portion 115. In addition, the terrace portion 116 may refer to an area between the electrode leads 111 and 112, some of which protrude outside the cell casing 114, and the cell body 113 located inside the cell casing 114, based on the edge of the cell casing 114.

[0049] The battery cell stack 120 may be formed by stacking a plurality of electrically connected battery cells 110 in one direction. The direction in which the plurality of battery cells 110 are stacked (hereinafter referred to as the "stacking direction") may be the y-axis direction (or the -y-axis direction, and hereinafter, the expression "axial direction" may be interpreted as including both + / - directions).

[0050] Meanwhile, since the battery cells 110 are arranged in one direction, the electrode leads of the battery cells 110 may be located on one side of the battery cell stack 120, or on both the one side and the other side opposite to the one side. In this manner, the side on which the electrode leads 111, 112, etc. of the battery cell stack 120 are located may be referred to as the front or rear side of the battery cell stack 120, and here, the direction from the front side to the rear side of the battery cell stack 120 or the opposite direction may be defined as the length direction of the battery cell stack 120, or may be the x-axis direction. The length direction of the battery cell stack 120 may be substantially the same as the length direction of the battery cells 110.

[0051] In addition, the surface on which the outermost battery cell 110 of the battery cell stack 120 is located can be referred to as the side surface of the battery cell stack 120, and the side surfaces of the battery cell stack 120 can be described as two surfaces facing each other on the y-axis.

[0052] The module frame 200 may be for protecting the battery cell stack 120 and electrical components connected to the battery cell stack 120 from external physical impact. The module frame 200 may be accommodated in an internal space of the module frame 200 connected to the battery cell stack 120. Here, the module frame 200 includes an internal surface and an external surface, and the internal space of the module frame 200 may be defined by the internal surface.

[0053] The structure of the module frame 200 may be various. As an example, the structure of the module frame 200 may be a monoframe structure. Here, the monoframe may be in the form of a metal plate material with an upper surface, a lower surface, and both side surfaces integrated. The monoframe may be manufactured by extrusion molding. As another example, the structure of the module frame 200 may be a structure in which a U-shaped frame and an upper plate (upper surface) are combined. In the case of a structure in which a U-shaped frame and an upper plate are combined, the structure of the module frame 200 may be formed by combining the upper plate with the upper side of a U-shaped frame, which is a metal plate material with a lower surface and both side surfaces combined or integrated, and each frame or plate may be manufactured by press molding. In addition, the structure of the module frame 200 may be provided as an L-shaped frame structure in addition to the monoframe or U-shaped frame, and may be provided as various structures not described in the above examples.

[0054] The structure of the module frame 200 may be provided in an open form along the length direction of the battery cell stack 120. The front and rear surfaces of the battery cell stack 120 may not be blocked by the module frame 200. The front and rear surfaces of the battery cell stack 120 may be blocked by a bus bar frame 300 or an end plate 400, which will be described later, and the front and rear surfaces of the battery cell stack 120 should be protected from external physical impacts and the like through the bus bar frame 300 or the end plate 400.

[0055] The top / bottom, front / rear, and both side surfaces of the module frame 200 may be described based on the description of the battery cell stack 120. Specifically, the top / bottom surfaces of the module frame 200 may be described as two surfaces facing each other on the z-axis, the front / rear surfaces of the module frame 200 may be described as two surfaces facing each other on the x-axis, and both side surfaces of the module frame 200 may be described as two surfaces facing each other on the y-axis. Here, the direction from the front surface to the rear surface or from the rear surface to the front surface may be the length direction of the module frame 200.

[0056] Meanwhile, although not shown, a compression pad may be located between the battery cell stack 120 and the inner surface of the module frame 200. In this case, the compression pad may be located between a side surface of the battery cell stack 120 and a side surface of the module frame 200, and may face at least one of the two battery cells 110 at both ends of the battery cell stack 120.

[0057] Furthermore, a thermally conductive resin may be injected between the battery cell stack 120 and the inner surface of the module frame 200, and the injected thermally conductive resin may form a thermally conductive resin layer (not shown) between the battery cell stack 120 and the inner surface of the module frame 200. In this case, the thermally conductive resin layer may be formed between the lower surface of the battery cell stack 120 and the lower surface (sometimes referred to as the bottom surface or bottom portion) of the module frame 200.

[0058] The busbar frame 300 may be located on one surface of the battery cell stack 120 to cover one surface of the battery cell stack 120 and to guide a connection between the battery cell stack 120 and an external device. The busbar frame 300 may be located on a front or rear surface of the battery cell stack 120. At least one of the busbars 510, 520 and a module connector may be attached to the busbar frame 300. One surface of the busbar frame 300 may be connected to the front or rear surface of the battery cell stack 120, and the other surface of the busbar frame 300 may be connected to the busbars 510, 520. There may be two busbar frames 300, and they may be located on the front and rear surfaces of the battery cell stack 120, respectively.

[0059] The bus bar frame 300 may include an electrically insulating material. The bus bar frame 300 can restrict the bus bars 510, 520 from contacting other parts of the battery cells 110, etc., other than the parts joined to the electrode leads 111, 112, and can prevent the occurrence of an electrical short circuit.

[0060] The end plate 400 may serve to protect the battery cell stack 120 and electrical components connected to the battery cell stack 120 from external physical impact by sealing the open side of the module frame 200. For this purpose, the end plate 400 may be manufactured from a material having a predetermined strength. For example, the end plate 400 may include a metal such as aluminum.

[0061] The end plate 400 may be coupled (joined, sealed or sealed) to the module frame 200 by covering the bus bar frame 300 or the bus bars 510, 520 located on one side of the battery cell stack 120. Each corner of the end plate 400 may be coupled to a corresponding corner of the module frame 200 by a method such as welding. In addition, an insulating cover 700 for electrical node insulation may be located between the end plate 400 and the bus bar frame 300. The insulating cover 700 may be located on the inner surface of the end plate 400 or may be in close contact with the inner surface of the end plate 400, but this is not necessarily the case.

[0062] There may be two end plates 400 , including a first end plate located on the front surface of the battery cell stack 120 and a second end plate located on the rear surface of the battery cell stack 120 .

[0063] The bus bars 510, 520 may be attached to one surface of the bus bar frame 300 and serve to electrically connect the battery cell stack 120 or the battery cells 110, etc., to an external device circuit. The bus bars 510, 520 may be located between the battery cell stack 120 or the bus bar frame 300 and the end plate 400, thereby providing protection against external impacts, etc., and minimizing deterioration in durability due to external moisture, etc.

[0064] The bus bars 510, 520 may be electrically connected to the battery cell stack 120 through the electrode leads 111, 112 of the battery cells 110. Specifically, the electrode leads 111, 112 of the battery cells 110 may pass through slits formed in the bus bar frame 300 and then be bent to be connected to the bus bars 510, 520. The battery cells 110 constituting the battery cell stack 120 may be connected in series or in parallel by the bus bars 510, 520.

[0065] Meanwhile, the bus bars 510, 520 may include a terminal bus bar 520 for forming an electrical connection between the battery modules 100. At least a portion of the terminal bus bar 520 may be exposed to the outside of the end plate 400 in order to connect to another external battery module 100, and the end plate 400 may be provided with a terminal bus bar opening 400H for this purpose. The terminal bus bar may be connected to another battery module 100 or a BDU (Battery Disconnect Unit) through a protrusion exposed through the terminal bus bar opening 400H, and may form a HV (High voltage) connection therewith.

[0066] Although not shown, the battery module 100 may include a sensing member for detecting and controlling phenomena such as overvoltage, overcurrent, and overheating of the battery cells 110. The sensing member is for a low voltage (LV) connection, and here the LV connection may mean a sensing connection for detecting and controlling the voltage of the battery cells. Voltage information and temperature information of the battery cells 110 may be transmitted to an external BMS (Battery Management System) through the sensing member.

[0067] The sensing member may include a temperature sensor that detects the temperature inside the battery module, a sensing terminal that senses the voltage value of the bus bars 510, 520, a module connector that transmits collected data to an external control device and receives a signal from the external control device, and / or a connecting member for connecting the module connector.

[0068] Here, the connecting member is disposed on the upper surface of the battery cell stack 120 in a form extending along the length direction, and may be a flexible printed circuit board (FPCB) or a flexible flat cable (FFC).

[0069] Here, the module connector may be attached to the bus bar frame 300 described above, and at least a portion of the module connector may be exposed to the outside through a module connector opening formed in the end plate 400.

[0070] Meanwhile, as described above, a fire may occur inside the battery module 100 in which the battery cells 110 are densely stacked. When a fire occurs in one battery module 100, heat, gas, or flames of the battery module 100 may be transferred to the adjacent battery modules 100, causing continuous fires between the battery modules 100. This may result in a decrease in durability and stability of the battery modules 100 or the battery pack including the battery modules 100.

[0071] Therefore, hereinafter, a cover layer 800 and a venting part 900 capable of improving the durability and stability of the battery module 100 by eliminating the above-mentioned ignition phenomenon will be described.

[0072] 3 and 4, the module frame 200 according to an embodiment of the present invention may include a venting portion 900 penetrating an inner surface and an outer surface of the module frame 200. The venting portion 900 may have a hole shape that communicates an inlet 900a formed on the inner surface of the module frame 200 with an outlet 900b formed on the outer surface. The venting portion 900 may communicate an inside of the battery module 100 sealed by the module frame 200 and the end plate 400 with an outside of the battery module 100.

[0073] The venting unit 900 is provided to exhaust heat, gas, flame, etc. generated when a fire occurs inside the battery module 100 to the outside of the battery module 100. The venting unit 900 can prevent continuous occurrence or transfer of a thermal runaway phenomenon by mitigating an internal ignition phenomenon of the module frame 200 and minimizing an increase in pressure or temperature. Specifically, when a fire occurs inside the module frame 200, heat, gas, sparks, flame, etc. caused by the ignition of the battery cell 110 are exhausted to the outside of the battery module 100 through the venting unit 900, so that the internal fire can be quickly extinguished and the ignition phenomenon can be further mitigated. In addition, by exhausting heat, gas, etc. through the venting unit 900, it is possible to prevent an excessive increase in pressure or temperature inside the battery module 100 and to delay the rate at which thermal runaway transfers in the internal space.

[0074] The venting portion 900 may be formed on at least one surface of the module frame 200. The venting portion 900 may be formed on an upper surface of the module frame 200. The venting portion 900 may be formed on a surface of the module frame 200 extending along the stacking direction or length direction of the battery cell stack 120.

[0075] There may be at least one venting portion 900 formed on the upper surface of the module frame 200. The more venting portions 900 formed on the module frame 200, the more rapidly the ignition phenomenon of the module frame 200 can be alleviated. When there are a plurality of venting portions 900, the venting portions 900 may be arranged in rows aligned in one direction and in columns aligned in a direction perpendicular to the one direction. In this case, the venting portions 900 may be formed over the entire surface of the module frame 200 as shown in the above drawings, but this is not necessarily the case and may be formed in a part of the surface of the module frame 200.

[0076] The shapes of the inlet 900a and the outlet 900b of the venting unit 900 may be rounded with a curvature as shown in the drawings, but this is not necessarily the case and the inlet 900a and the outlet 900b of the venting unit 900 may be circular, elliptical, or polygonal with vertices. In addition, since it is preferable that the heat, gas, or flame discharged through the venting unit 900 is quickly diffused to the outside of the battery module 100, the size of the outlet 900b may be larger than the size of the inlet 900a.

[0077] Meanwhile, the direction from the inlet 900a of the venting unit 900 to the outlet 900b may be a direction in which gas inside the battery module 100 is discharged to the outside. In the above-mentioned drawings, the direction from the inlet 900a of the venting unit 900 to the outlet 900b is shown to be perpendicular to one surface of the module frame 200 in which the venting unit 900 is formed, but this is not necessarily the case. The positions of the inlet 900a and the outlet 900b of the venting unit 900 may be changed to form a hole structure such that the discharge direction forms an acute angle with one surface of the module frame 200. As such, the hole of the venting unit 900 has an oblique structure, which minimizes exposure of the inside of the battery module 100 and prevents foreign matter floating in the air from entering the inside of the battery module 100 due to gravity.

[0078] By changing the positions of the inlet 900a and the outlet 900b of the venting unit 900 so that the exhaust direction forms an angle (acute angle), it is possible to change (adjust) the direction of heat, gas, or flame exhausted from the venting unit 900. As a result, the length of the exhaust path increases, and the gas exhausted through the outlet 900b of the venting unit 900 can have a lower temperature. In addition, when the exhaust direction of the venting unit 900 is formed in a direction in which the adjacent battery modules 100 are not located, it is possible to minimize the phenomenon of heat transmission between the adjacent battery modules 100.

[0079] When there are a plurality of venting parts 900, the exhaust directions of the plurality of venting parts 900 may be the same or different from each other. When the exhaust directions of the plurality of venting parts 900 are formed to be different from each other, gas exhausted from the venting parts 900 can be diffused in various directions to a larger space outside the battery module 100. As a result, gas can be quickly exhausted from the battery module 100, and effects such as preventing heat generation of the battery module 100 can be achieved.

[0080] Meanwhile, when the module frame 200 is provided with a venting portion 900 for communicating the inside and the outside as in this embodiment, dust, impurities, etc. from the outside of the module frame 200 may enter the inside of the module frame 200 through the hole structure of the venting portion 900, or when an internal fire occurs, external oxygen may be supplied along the venting portion 900, which may promote a thermal runaway phenomenon. In addition, since the gas, sparks, etc. discharged through the venting portion 900 of the module frame 200 may have a very high temperature and pressure, the discharged gas, sparks, etc. may be transferred to the adjacent battery module 100, causing a problem of inducing a thermal runaway phenomenon in the adjacent battery module 100.

[0081] Therefore, the venting portion 900 of this embodiment may be provided with a cover layer 800 that can close the hole before a thermal runaway phenomenon occurs and open the hole when a thermal runaway phenomenon occurs, thereby reducing the temperature and pressure of the released gas, etc.

[0082] Further, referring to FIG. 4, the battery module 100 according to an embodiment of the present invention may include a cover layer 800 covering the opening of the hole structure of the venting portion 900 .

[0083] Here, the expression "cover layer" is intended to describe the form of a film for covering the hole of the venting portion 900, and therefore it should be made clear in advance that it can be expressed by changing it to a lid, hood, lid, cap, or other similar words.

[0084] The cover layer 800 may be located under one surface of the module frame 200 or the end plate 400 on which the venting portion 900 is formed. As an example, the cover layer 800 may be located between the upper surface of the battery cell stack 120 and the upper surface of the module frame 200.

[0085] The cover layer 800 is disposed to cover the inlet 900a, thereby covering the hole of the venting portion 900. The cover layer 800 may be provided in a plate shape to cover the hole of the venting portion 900. The cover layer 800 may be provided in a pad shape to cover the hole of the venting portion 900.

[0086] The cover layer 800 may include multiple layers. The cover layer 800 may include a barrier layer 810 that can be partially broken by heat or pressure, and refractory layers 820, 830 made of a refractory material that can withstand a predetermined temperature or pressure. Here, the barrier layer 810 may be located closer to the battery cell stack 120 than the refractory layers 820, 830, and in consideration of their locations, the barrier layer 810 may be referred to as a first layer, and the refractory layers 820, 830 may be referred to as a second layer. Here, the refractory layer may include two or more layers as shown in FIG. 4, and for convenience of explanation, a layer located relatively closer to the barrier layer 810 may be referred to as a first refractory layer 820, and a layer located farther away may be referred to as a second refractory layer 830. Alternatively, in their locations, the barrier layer 810 may be referred to as the first layer, the first refractory layer 820 as the second layer, and the second refractory layer 830 as the third layer.

[0087] Meanwhile, a number of venting parts may be formed in the refractory layers 820 and 830. To distinguish from the venting part 900 formed in the module frame 200, the venting parts formed in the refractory layers 820 and 830 may be referred to as sub-venting parts 822 and 832. Each of the sub-venting parts 822 and 832 may have an inlet and an outlet, and the inlet may be located relatively lower than the outlet. The sub-venting parts 822 and 832 formed in the refractory layers 820 and 830 may guide a gas exhaust path so that gas, sparks, etc. generated in the battery cells 110 are exhausted to the venting part 900 without moving to other spaces in the battery module 100.

[0088] The refractory layers 820 and 830 may be made of a material capable of withstanding a high temperature and pressure environment for a certain period of time. For example, the refractory layers 820 and 830 may be made of aluminum, stainless steel (SUS), or clad metal. The refractory layers 820 and 830 may be extruded materials capable of withstanding a high temperature and pressure environment for a certain period of time.

[0089] The barrier layer 810 is disposed between the refractory layers 820, 830 and the battery cell stack 120, and prevents foreign matter from being introduced into the battery module 100 before a thermal runaway phenomenon occurs in the battery module 100, and can open the venting portion 900 and the sub-venting portions 822, 832 by being removed by heat or pressure after a thermal runaway phenomenon occurs in the battery module 100. Although not specifically shown in FIG. 4, the upper surface of the barrier layer 810 may be partially protruding, and the protruding portion is inserted into the first sub-venting portion 822 formed in the first refractory layer 820, thereby minimizing the inflow of foreign matter into the battery module 100.

[0090] The barrier layer 810 may include a material that melts due to the internal temperature of the battery module 100. The barrier layer 810 may include a material that melts due to heat, high-temperature gas, or sparks emitted from the battery cell 110. The barrier layer 810 may be made of a material having a melting point below a predetermined range. The barrier layer 810 may be provided with a material having a melting point of 300° C. or less. As a specific example, the barrier layer 810 may include a thermoplastic polymer resin having a melting point of about 200° C. or less. More specifically, the barrier layer 810 may be made of a material having a melting point of about 100° C. or more and 200° C. or less, such as polyethylene or polypropylene.

[0091] The barrier layer 810 may include a material for mitigating an ignition phenomenon when the battery module 100 ignites inside. For example, the barrier layer 810 may include a fire extinguishing agent. When the barrier layer 810 includes the fire extinguishing agent, the battery module 100 may have a self-extinguishing function. Here, the fire extinguishing agent may be a powder-type fire extinguishing agent material. The fire extinguishing agent may generate carbon dioxide and water vapor through a pyrolysis reaction when the battery module 100 ignites inside, and the generated carbon dioxide and water vapor may suppress the flame by preventing external oxygen from flowing into the battery module 100. The fire extinguishing agent may absorb heat generated in the battery module by performing a pyrolysis reaction, which is an endothermic reaction, and may also block the supply of external oxygen by generating carbon dioxide and water vapor. This may effectively delay the flame and heat wave speed inside the battery module 100, thereby improving the safety of the battery module.

[0092] The barrier layer 810 may include one or more extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates. More specific examples of the extinguishing agent may include sodium bicarbonate (NaHCO3), potassium bicarbonate (KHCO3), ammonium phosphate (NH4H2PO3), and a mixture of potassium bicarbonate (KHCO3) and iodine ((NH2)2CO). When the cover layer 800 includes potassium bicarbonate (KHCO3), potassium carbonate (K2CO3), water vapor (H2O), and carbon dioxide (CO2) may be generated through a thermal decomposition reaction of potassium bicarbonate. The generated water vapor can counteract the flame inside the battery module 100, and the generated carbon dioxide can block the flame from contacting oxygen, etc. However, the extinguishing agent of this embodiment is not limited thereto, and any material that has a fire-extinguishing function can be used without limitation.

[0093] As such, the barrier layer 810 may be provided by being manufactured from a material having the above-mentioned physical properties, but may also be provided from a material having multiple physical properties or a composite of materials having each physical property.

[0094] The effects obtained by providing the cover layer to the battery module of this embodiment will be described in more detail below.

[0095] Fig. 6 is a cross-sectional view taken along the cutting line BB in Fig. 3. Fig. 7 is a cross-sectional view taken along the cutting line CC in Fig. 3. Fig. 8 is a diagram showing a state when an internal ignition occurs in the battery module shown in Fig. 3. Here, Fig. 6 shows a cross-section in the length direction of the battery module 100, and Fig. 7 shows a cross-section in the width direction of the battery module 100.

[0096] 6 and 7, the venting portion 900 formed in the module frame 200 and at least a portion of the sub-venting portions 822, 832 formed in the refractory layers 820, 830 may overlap in the length direction (x-axis) of the battery module 100. The venting portion 900 and at least a portion of the sub-venting portions 822, 832 may overlap in the width direction (y-axis) of the battery module 100.

[0097] At least a portion of the venting portion 900 formed in the module frame 200 and the second sub-venting portion 832 formed in the second refractory layer 830, or the second sub-venting portion 832 and the first sub-venting portion 822 formed in the first refractory layer 820, may overlap in the length direction (x-axis) of the battery module 100. At least a portion of the venting portion 900 and the second sub-venting portion 832, or the second sub-venting portion 832 and the first sub-venting portion 822 may overlap in the width direction (y-axis).

[0098] When the holes formed in the module frame 200 and the refractory layers 820 and 830 partially overlap each other, the path of gas and the like discharged to the outside of the battery module 100 through the holes can be switched. Specifically, since the holes formed in the module frame 200 and the refractory layers 820 and 830 do not completely correspond to each other, the path through which gas and the like are discharged can form an angle with the z-axis as shown by the arrows in FIGS. 6 and 7. The path through which gas and the like are discharged can be formed in a zigzag shape. Since the holes formed in the module frame 200 and the refractory layers 820 and 830 do not completely correspond to each other, the discharge path can be longer than when the holes correspond to each other. The gas discharge path may be longer than the shortest distance between the upper surface of the battery cell stack 120 and the module frame 200. As the gas discharge path is longer, the temperature and pressure of the gas discharged to the outside of the battery module 100 can be further lowered, and the gas can have low energy that does not affect the adjacent battery modules 100.

[0099] Although not specifically shown, the venting portion 900 and the sub-venting portions 822, 832 formed in the module frame 200 and the refractory layers 820, 830 may have an oblique hole structure. When the holes of the venting portion 900 and the sub-venting portions 822, 832 are formed to form an acute angle with one surface of the module frame 200, the above-mentioned switching of the exhaust path can be more effectively implemented.

[0100] 8, when a flame, gas, or spark occurs inside the battery module 100, specifically, in some of the battery cells 110, the barrier layer 810 around the ignition may be physically broken or chemically melted by heat or pressure, resulting in penetration, and thus the venting portion 900 and the sub-venting portions 822 and 832 may be opened. Heat, gas, or sparks inside the battery module 100 may be discharged through the opened venting portion 900 and the sub-venting portions 822 and 832, thereby mitigating the ignition of the battery module 100. Here, the process in which the barrier layer 810 is penetrated, i.e., opened, may involve an endothermic reaction, and the temperature inside the battery module 100 may be reduced as the barrier layer 810 absorbs internal heat. Heat, gas, etc. released to the outside of the venting portion 900 through the endothermic reaction of the barrier layer 810 may lose enough energy to not affect the adjacent battery module 100, and the sparks may lose energy and turn into particles, thereby not promoting thermal runaway in the adjacent battery module 100.

[0101] Meanwhile, the above description has focused on the effect of the barrier layer 810 being released through a chemical reaction. However, even if the barrier layer 810 is physically released by pressure or the like, the kinetic energy of the gas or sparks is reduced in the process of removing the barrier layer 810. Therefore, the heat, gas, etc. released to the outside of the battery module 100 lose energy to an extent that does not affect adjacent battery modules 100, and the sparks lose energy and turn into particles, thereby suppressing the thermal runaway phenomenon of the adjacent battery modules 100.

[0102] Meanwhile, the barrier layer 810 can be opened only when heat or pressure exceeding a predetermined range is applied, so that only the barrier layer 810 located around the area where the ignition occurs can be opened individually. The barrier layer 810 can prevent the promotion of thermal runaway caused by the inflow of additional oxygen by opening only some of the multiple venting portions 900 and sub-venting portions 822 and 832.

[0103] Specifically, when a ignition occurs in the first battery cell 110a, the first portion 810a of the barrier layer 810 corresponding to the first battery cell 110a is opened to allow gas, flame, etc. generated in the first battery cell 110a to be discharged. At this time, the second portion 810b of the barrier layer 810 located on the upper portion of the second battery cell 110b in which no ignition occurs in the battery module 100 may not be opened, and the first sub-venting portion 822 corresponding to the second portion 810b may be in a closed state. In this way, by maintaining the barrier layer 810 in the other portion in which no ignition occurs in a closed state, it is possible to block external oxygen from further flowing into the battery module 100, and it is possible to suppress the amplification of a flame generated in the battery module 100 by the flowing in oxygen.

[0104] Meanwhile, the barrier layer 810 may include a protrusion 812 partially protruding from one surface of the barrier layer 810. The protrusion 812 may be formed on the upper surface of the barrier layer 810. In this case, the size of the protrusion 812 may be similar to or smaller than the size of the first sub-venting portion 822, and thus the protrusion 812 may be inserted into the first sub-venting portion 822 formed in the first refractory layer 820. The outer shape of the protrusion 812 may correspond to the inner shape of the first sub-venting portion 822, and thus the hole of the first sub-venting portion 822 may be closed by the protrusion 812. When the protrusion 812 of the barrier layer 810 is provided to fill the hole of the first sub-venting portion 822 of the first refractory layer 820, the region where the protrusion 812 is formed in the barrier layer 810 has a large thickness. When the protrusions 812 are formed on the barrier layer 810, the space that the barrier layer 810 occupies inside the battery module 100 is the same, but since the thick barrier layer 810 must be opened in order for the battery module 100 to release gases, etc. to the outside, the fire suppression effect of the barrier layer 810 may be greater. However, this is not necessarily the case, and the barrier layer 810 may be provided so as to have a flat shape without the protrusions 812 being formed on the barrier layer 810.

[0105] Meanwhile, the battery module 100 may be included in a battery pack. The battery pack may include one or more battery modules according to the present embodiment, and may further include a battery management system (BMS) for managing the temperature and voltage of the battery, a cooling device, and the like.

[0106] The battery module and the battery pack including the battery module can be applied to various devices, including transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto, and the battery module and the battery pack including the battery module can be applied to various devices, which also fall within the scope of the present invention.

[0107] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the present invention. [Explanation of symbols]

[0108] 10 Battery module 11 Battery Cell 12 Battery cell stack 20 Frames 40 End Plate 100 Battery Module 110a First battery cell 110b Second battery cell 110p protrusion 110 Battery Cell 111 Electrode lead 112 Electrode Lead 113 Cell Body 114 Cell Case 114a Both ends 114b Both ends 114c One side 114sa sealing part 114sb sealing part 114sc sealing part 115 Connection part 116 copies 120 Battery cell stack 200 module frame 300 Busbar Frame 400 End Plate 400H Terminal busbar opening 510 Busbar 520 Busbar 700 Insulating Cover 800 Cover Layer 810 Barrier Layer 810a Part 1 810b Part 2 812 Protrusion 820 (1st) Refractory layer 822 (1st) Sub-venting Section 830 Second refractory layer 832 (2nd) Sub-venting Section 900 Venting section 900a inlet 900b outlet BB cutting line BMS external CC cutting line

Claims

1. a battery cell stack in which a plurality of battery cells are stacked in one direction; a module frame housing the battery cell stack, the module frame having an interior surface and an exterior surface; A battery module comprising: At least one vent is formed on one surface of the module frame, the vent penetrating the inner surface and the outer surface; a cover layer including a barrier layer and a refractory layer is disposed between the one surface of the module frame on which the venting portion is formed and the battery cell stack; the barrier layer prevents a foreign object from being introduced into the battery module before the battery module experiences thermal runaway, and is removed by heat or pressure after the battery module experiences thermal runaway; the barrier layer is located below the refractory layer; The refractory layer is formed with a plurality of sub-venting portions penetrating the refractory layer, the barrier layer covers the holes in the sub-venting portion; When an ignition phenomenon occurs in the battery cell stack, the barrier layer is opened in a portion corresponding to the portion where the ignition phenomenon occurs.

2. The battery module according to claim 1 , wherein the one surface of the module frame is a top surface of the module frame.

3. A battery cell stack in which a plurality of battery cells are stacked in one direction; a module frame housing the battery cell stack, the module frame having an interior surface and an exterior surface; A battery module comprising: At least one vent is formed on one surface of the module frame, the vent penetrating the inner surface and the outer surface; a cover layer including a barrier layer and a refractory layer is disposed between the one surface of the module frame on which the venting portion is formed and the battery cell stack; At least one sub-venting portion is formed in the refractory layer, the barrier layer prevents a foreign object from being introduced into the battery module before the battery module experiences thermal runaway, and is removed by heat or pressure after the battery module experiences thermal runaway; The barrier layer includes a protrusion that protrudes partially from the one surface of the barrier layer, the protrusion being inserted into the sub-venting portion.

4. The battery module according to claim 3 , wherein the venting portion and at least a portion of the sub-venting portion overlap in a longitudinal direction of the battery module.

5. The battery module according to claim 3 , wherein the venting portion and at least a portion of the sub-venting portion overlap in a width direction of the battery module.

6. A battery cell stack in which a plurality of battery cells are stacked in one direction; a module frame housing the battery cell stack, the module frame having an interior surface and an exterior surface; A battery module comprising: At least one vent is formed on one surface of the module frame, the vent penetrating the inner surface and the outer surface; a cover layer including a barrier layer and a refractory layer is disposed between the one surface of the module frame on which the venting portion is formed and the battery cell stack; At least one sub-venting portion is formed in the refractory layer, the barrier layer prevents a foreign object from being introduced into the battery module before the battery module experiences thermal runaway, and is removed by heat or pressure after the battery module experiences thermal runaway; The sub-venting portion or the hole of the venting portion forms an acute angle with the one surface of the module frame.

7. the refractory layer includes a first refractory layer and a second refractory layer; The battery module of claim 1 , wherein the first refractory layer is located closer to the barrier layer than the second refractory layer.

8. At least one first sub-venting portion is formed in the first refractory layer, The battery module of claim 7 , wherein the second refractory layer is formed with at least one second sub-venting portion.

9. The battery module of claim 8 , wherein the first sub-venting portion and at least a portion of the second sub-venting portion overlap in a length direction of the battery module.

10. The battery module of claim 8 , wherein the first sub-venting portion and at least a portion of the second sub-venting portion overlap in a width direction of the battery module.

11. The battery module according to claim 1 , wherein the barrier layer includes a material having a melting point of 300° C. or less.

12. A battery cell stack in which a plurality of battery cells are stacked in one direction; a module frame housing the battery cell stack, the module frame having an interior surface and an exterior surface; A battery module comprising: At least one vent is formed on one surface of the module frame, the vent penetrating the inner surface and the outer surface; a cover layer including a barrier layer and a refractory layer is disposed between the one surface of the module frame on which the venting portion is formed and the battery cell stack; the barrier layer prevents a foreign object from being introduced into the battery module before the battery module experiences thermal runaway, and is removed by heat or pressure after the battery module experiences thermal runaway; The barrier layer comprises one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

13. The battery module according to claim 1 , wherein the refractory layer comprises aluminum, stainless steel (SUS), or clad metal.

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

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