Battery module and battery pack including same

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; a module frame that houses the battery cell stack and has an inner surface and an outer surface; and an end plate that is coupled to the module frame and covers a front or rear surface of the battery cell stack, wherein the module frame is formed with at least one hole-shaped vent that defines an inlet formed on the inner surface and an outlet formed on the outer surface, and the hole of the vent is covered with a barrier layer.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0048791 dated April 14, 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 same, and more particularly to a battery module with enhanced safety and a battery pack including the same. [Background technology]

[0003] As technological development and demand for mobile devices increases, 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 demands.

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

[0005] Recently, as the need for large-capacity secondary battery structures has increased, including the use of secondary batteries as energy storage sources, there has been an increasing demand for battery packs with medium to large modular structures that assemble battery modules in which multiple secondary batteries are connected in series / parallel.

[0006] Meanwhile, when a battery pack is constructed by connecting a plurality of battery cells in series / parallel, a common method is to construct a battery module consisting of at least one battery cell, and then use the at least one battery module to add other components to construct the battery pack.

[0007] Since the battery cells constituting such medium- to large-sized battery modules are made up of secondary batteries that can be charged and discharged, such high-power, large-capacity secondary batteries generate a large amount of heat during the charging and discharging process.

[0008] The battery module includes a battery cell stack in which a plurality of battery cells are stacked, a frame that houses the battery cell stack, and end plates that cover the front and rear surfaces of the battery cell stack.

[0009] Fig. 1 is a diagram showing the state of a battery module installed in a conventional battery pack when it catches fire, and Fig. 2 is a diagram showing the state of a flame affecting adjacent battery modules when a battery module installed in a conventional battery pack catches fire, which is the part AA in Fig. 1.

[0010] 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, end plates 40 formed on the front and rear surfaces of the battery cell stack 12, and terminal bus bars 50 that protrude from the end plates.

[0011] The battery cell stack can be arranged in a sealed structure by combining the frame 20 and the end plates 40. If the internal pressure of the battery cells 11 increases due to overcharging or other reasons, high-temperature heat, gas, or flames may be released outside the battery cells 11. At this time, the heat, gas, or flames released from one battery cell 11 may be transferred to other adjacent battery cells 11 at close intervals, causing continuous ignition. In addition, the heat, gas, or flames released from each battery cell 11 may be released toward the openings formed in the end plates 40, and in this process, the bus bars 50 located between the end plates 40 and the battery cells 11 may be damaged.

[0012] Furthermore, since the plurality of battery modules 10 in the battery pack are arranged with at least two end plates 40 facing each other, if heat, gas, flame, etc. generated within the battery module 10 is discharged to the outside of the battery module 10, it may affect the performance and stability of the plurality of battery cells 11 in other adjacent battery modules 10.

[0013] Therefore, it is necessary to develop a battery module 10 that has improved durability and safety by effectively slowing the heat propagation speed in the event of an internal fire 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]

[0014] An object of the present invention is to provide a battery module and a battery pack including the same, which have enhanced safety by suppressing high-temperature heat and flames emitted when a fire occurs in the battery module.

[0015] 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]

[0016] 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; a module frame that houses the battery cell stack and has an inner surface and an outer surface; and an end plate that is coupled to the module frame and covers a front or rear surface of the battery cell stack, wherein the module frame is formed with at least one hole-shaped vent that defines an inlet formed on the inner surface and an outlet formed on the outer surface, and the hole of the vent is covered with a barrier layer.

[0017] The barrier layer can include a material with a melting point of about 200°C or less.

[0018] The barrier layer may include heat-resistant plastic, carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), a mica-based material, a ceramic-based material, or silicon.

[0019] The barrier layer may include one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

[0020] The barrier layer may be disposed between the battery cell stack and one surface of the module frame where the vent is formed.

[0021] The barrier layer may fill the inner space of the hole of the vent portion.

[0022] The barrier layer may include a first barrier layer filling an internal space of the hole of the vent, and a second barrier layer positioned between the battery cell stack and one surface of the module frame on which the vent is formed.

[0023] When a direction in which the plurality of battery cells are stacked is defined as a stacking direction, the venting portion may be formed on one surface of the module frame extending along the stacking direction.

[0024] The venting portion may be formed on the upper surface of the module frame.

[0025] An exhaust direction of the vent may form an acute angle with one surface of the module frame on which the vent is formed, and the exhaust direction of the vent may be a direction from the inlet to the outlet.

[0026] The plurality of battery cells may include a first battery cell and a second battery cell, and when a first portion of the barrier layer corresponding to a first vent formed at a position corresponding to the first battery cell is opened, a second portion of the barrier layer corresponding to a second vent formed at a position corresponding to the second battery cell may not be opened.

[0027] A battery pack according to another embodiment of the present invention includes the above-described battery module. [Effects of the Invention]

[0028] According to an embodiment, a module frame having holes and a cover for covering the holes are provided in the battery module, so that the holes can be closed before a fire occurs to prevent contaminants from being introduced into the battery module from the outside, and when a fire occurs, the holes can be opened to block oxygen and exhaust gas, thereby suppressing high-temperature heat, gas, and fire.

[0029] 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 claims. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 10 is a diagram showing a state in which a battery module attached to a conventional battery pack catches fire. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1, showing the state of flames affecting adjacent battery modules when a battery module mounted in a conventional battery pack catches fire. FIG. [Figure 3] 1 is a perspective view showing an example of a battery module according to an embodiment of the present invention; [Figure 4] FIG. 4 is an exploded perspective view of the battery module of FIG. 3. [Figure 5] 5 is a perspective view of a battery cell included in the battery module of FIG. 4. FIG. [Figure 6]FIG. 4 is a cross-sectional view taken along the line BB in FIG. 3. [Figure 7] 4 is a cross-sectional view illustrating a state after a pyrolysis reaction occurs when a flame occurs in a battery module according to an embodiment of the present invention. [Figure 8] FIG. 4 is a cross-sectional view showing a battery module according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, 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 embodiments. 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.

[0032] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0033] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily enlarged or reduced for the 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 the convenience of explanation.

[0034] Furthermore, when a layer, film, region, plate, or other portion is described as being "on" or "above" another portion, this should be interpreted as including not only the case where the layer, film, region, plate, or other portion is "directly on" the other portion, but also the case where there are other portions therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "directly on" another portion, it means that there are no other portions therebetween. Furthermore, being "on" or "above" a reference portion means being located above or below the reference portion, and does not necessarily mean being located "on" or "above" the opposite direction of gravity. Meanwhile, descriptions of being "on" or "above" another portion, as well as descriptions of being "below" or "below" another portion, should be understood with reference to the above content.

[0035] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that it may further include other elements, unless specifically stated to the contrary.

[0036] Furthermore, throughout the specification, the term "on a plane" means the part in question when viewed from above, and the term "on a cross section" means the part in question when viewed from the side, cut vertically.

[0037] Hereinafter, a battery module according to an embodiment of the present invention will be described.

[0038] 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 of Fig. 3, and Fig. 5 is a perspective view of a battery cell included in the battery module of Fig. 4.

[0039] 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 that is positioned on the front and / or rear surface of the battery cell stack 120, end plates 400 that cover the front and / or rear surface of the battery cell stack 120, and bus bars 510, 520 that are mounted on the bus bar frame 300.

[0040] The battery cells 110 may be provided in a pouch shape, which maximizes the number of cells stacked per unit area. The pouch-shaped battery cells 110 may be manufactured by placing 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 the sealing portion of the cell case 114. However, it is obvious that the battery cells 110 do not necessarily have to be provided in a pouch shape, and may be provided in a prismatic, cylindrical, or other various shapes as long as the storage capacity required by the device to be subsequently installed is achieved.

[0041] 5, the battery cell 110 may include two electrode leads 111 and 112. The electrode leads 111 and 112 may each have a structure that protrudes from one end of the cell body 113. Specifically, one end of each electrode lead 111 and 112 is located inside the battery cell 110 and is electrically connected to the positive or negative electrode of the electrode assembly, and the other end of each electrode lead 111 and 112 is led out of the battery cell 110 and is electrically connected to a separate member, for example, bus bars 510 and 520.

[0042] The electrode assembly in the cell case 114 can be sealed by sealing portions 114sa, 114sb, and 114sc. The sealing portions 114sa, 114sb, and 114sc of the cell case 114 can be disposed on both end portions 114a and 114b and one side portion 114c connecting them.

[0043] The cell casing 114 generally has a laminate structure of a resin layer / a metal thin film layer / a resin layer. For example, if the cell casing surface is made of an O(oriented)-nylon layer, it tends to slip easily due to external impact when stacking multiple battery cells 110 to form a medium- to large-sized battery module 100. Therefore, to prevent this and maintain a stable stacked structure of the battery cells 110, an adhesive member such as a pressure-sensitive adhesive such as double-sided tape or a chemical adhesive that bonds through a chemical reaction when bonded can be attached to the surface of the cell casing 114 to form the battery cell stack 120.

[0044] The connecting portion 115 may refer to a region extending along the length of one end of the cell casing 114 where the sealing portions 114sa, 114sb, and 114sc are not located. A protruding portion 110p of the battery cell 110, called a butt ear, may be formed at the end of the connecting portion 115. In addition, the terrace portion 116 may refer to a region 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.

[0045] Meanwhile, the battery cell 110 provided in a pouch shape may have a length, width, and thickness, and the length direction, width direction, and thickness direction of the battery cell 110 may be perpendicular to each other.

[0046] Here, the length direction of the battery cell 110 can be defined as the direction in which the electrode leads 111 and 112 protrude from the cell case 114. The length direction of the battery cell 110 can be defined as the x-axis direction or the −x-axis direction.

[0047] 4, the width direction of the battery cell 110 may be the z-axis direction or the -z-axis direction extending from one side 114c of the battery cell 110 to the connecting portion 115 or from the connecting portion 115 to one side 114c. The thickness direction of the battery cell 110 may be defined as the y-axis direction or the -y-axis direction perpendicular to the width direction and the length direction.

[0048] 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 'axis direction' may be interpreted to include both + / - directions) as shown in Figures 3 and 4.

[0049] Here, the direction from the front surface to the rear surface of the battery cell stack 120 or the opposite direction can be defined as the length direction of the battery cell stack 120, which may be the x-axis direction. Also, the direction from the top surface to the bottom surface of the battery cell stack 120 or the opposite direction can be defined as the width direction of the battery cell stack 120, which may be the z-axis direction.

[0050] The length direction of the battery cell stack 120 may be substantially the same as the length direction of the battery cells 110. In this case, the electrode leads 111, 112 of the battery cells 110 may be disposed on the front and rear surfaces of the battery cell stack 120. In this case, the bus bars 510, 520 of the battery module 100 may be disposed close to the front and rear surfaces of the battery cell stack 120 so as to easily form an electrical connection with the electrode leads 111, 112.

[0051] The module frame 200 may be configured to protect the battery cell stack 120 and the electrical components connected thereto from external physical impacts. The module frame 200 may accommodate the battery cell stack 120 and the electrical components connected thereto in an internal space of the module frame 200. Here, the module frame 200 includes an internal surface 200a (see FIG. 6) and an external surface 200b (see FIG. 6), and the internal space of the module frame 200 may be defined by the internal surface 200a.

[0052] The module frame 200 may have a variety of structures. As an example, the module frame 200 may have a mono-frame structure. Here, the mono-frame may be in the form of a metal plate with an integrated top, bottom, and both side surfaces. The mono-frame may be manufactured by extrusion molding. As another example, the module frame 200 may have a structure in which a U-shaped frame and an upper plate (upper surface) are coupled together. In the case of a structure in which a U-shaped frame and an upper plate are coupled together, the module frame 200 may be formed by coupling the upper plate to the top of a U-shaped frame made of a metal plate with an integrated or coupled bottom and both side surfaces, and each frame or plate may be manufactured by press molding. Furthermore, the module frame 200 may have an L-shaped frame structure in addition to a mono-frame or U-shaped frame, and may have various structures not described in the above examples.

[0053] The module frame 200 structure 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 covered by the module frame 200. The electrode leads 111, 112 of the battery cells 110 may not be covered by the module frame 200. The front and rear surfaces of the battery cell stack 120 may be covered by a bus bar frame 300, end plate 400, or bus bars 510, 520, which will be described later, and this should protect the front and rear surfaces of the battery cell stack 120 from external physical impacts, etc.

[0054] Meanwhile, a compression pad 150 may be disposed between the battery cell stack 120 and one side of the inner surface of the module frame 200. In this case, the compression pad 150 may be disposed on the y-axis of the battery cell stack 120 and may face at least one of the two battery cells 110 at both ends of the battery cell stack 120.

[0055] Furthermore, although not shown, a thermally conductive resin may be injected between the inner surfaces of the battery cell stack 120 and the module frame 200, and the injected thermally conductive resin may form a thermally conductive resin layer (not shown) between one side of the inner surfaces of the battery cell stack 120 and the module frame 200. In this case, the thermally conductive resin layer may be disposed on the z-axis of the battery cell stack 120, and the thermally conductive resin layer may be formed between the bottom surface (or bottom) of the battery cell stack 120 and the module frame 200, which is located on the -z-axis.

[0056] The bus bar frame 300 may be positioned on one side of the battery cell stack 120 to cover that side and guide the connection between the battery cell stack 120 and an external device. The bus bar frame 300 may be disposed on the front or rear side of the battery cell stack 120. At least one of bus bars 510, 520 and a module connector may be attached to the bus bar frame 300. For a specific example, referring to FIGS. 3 and 4 , one side of the bus bar frame 300 is connected to the front or rear side of the battery cell stack 120, and the other side of the bus bar frame 300 is connected to the bus bars 510, 520.

[0057] The bus bar frame 300 may include an electrically insulating material. The bus bar frame 300 may limit contact between the bus bars 510 and 520 and other parts of the battery cells 110 other than the parts connected to the electrode leads 111 and 112, thereby preventing an electrical short circuit from occurring.

[0058] Although not shown, there may be two bus bar frames 300, including a first bus bar frame (shown as drawing number 300) located on the front surface of the battery cell stack 120 and a second bus bar frame (not shown) located on the rear surface of the battery cell stack 120.

[0059] The end plates 400 may serve to protect the battery cell stack 120 and the electrical components connected thereto from external physical impact by sealing the open side of the module frame 200. To this end, the end plates 400 may be made of a material having a predetermined strength. For example, the end plates 400 may include a metal such as aluminum.

[0060] The end plate 400 can be coupled (joined, sealed, or hermetically sealed) to the module frame 200 while 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 can be coupled to a corresponding corner of the module frame 200 by welding or other methods. In addition, an insulating cover 800 for electrical insulation can be disposed between the end plate 400 and the bus bar frame 300. The insulating cover 800 can be disposed on the inner surface of the end plate 400 and can be in close contact with the inner surface of the end plate 400, but this is not necessarily the case.

[0061] The end plate 400 may be two in number, 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 .

[0062] The first end plate can be coupled to the module frame 200 while covering the first bus bar frame on the front surface of the battery cell stack 120, and the second end plate can be coupled to the module frame 200 while covering the second bus bar frame. In other words, the first bus bar frame can be disposed between the first end plate and the front surface of the battery cell stack 120, and the second bus bar frame can be disposed between the second end plate and the rear surface of the battery cell stack 120.

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

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

[0065] The bus bars 510, 520 may include a terminal bus bar 520 for electrically connecting one battery module 100 to another battery module 100. At least a portion of the terminal bus bar 520 may be exposed to the outside of the end plate 400 to be connected to another external battery module 100, and the end plate 400 may be provided with a terminal bus bar opening 400H for this purpose.

[0066] Unlike the other bus bars 510, the terminal bus bar 520 may further include a protruding portion that protrudes upward, and the protruding portion is exposed to the outside of the battery module 100 through the terminal bus bar opening 400H. The terminal bus bar 520 may be connected to other battery modules 100 or a BDU (Battery Disconnect Unit) through the protruding portion exposed through the terminal bus bar opening 400H, and may form an HV (High Voltage) connection therewith.

[0067] Although not shown, the battery module 100 may include a sensing member that detects and controls phenomena such as overvoltage, overcurrent, and overheating of the battery cells 110. 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 and 520, a module connector that transmits collected data to an external control device and receives signals from the external control device, and / or a connecting member for connecting the same.

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

[0069] The module connector can transmit data acquired from the temperature sensor and / or sensing terminal to a BMS (Battery Management System), and the BMS can control charging and discharging of the battery cells 110 based on the collected voltage data. The module connector can be attached to the bus bar frame 300 described above. At least a portion of the module connector is exposed to the outside of the end plate 400, and the end plate 400 may be provided with a module connector opening (not shown) for this purpose. In this way, the end plate 400 may be formed with a terminal bus bar opening 400H and a module connector opening, which can be collectively referred to as 'openings'.

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

[0071] Therefore, the following will describe the venting part 900 and the barrier layer 920 that can improve the durability and stability of the battery module 100 by eliminating the above-mentioned ignition phenomenon.

[0072] Fig. 6 is a cross-sectional view taken along the line BB in Fig. 3. Fig. 7 is a cross-sectional view showing a state after a pyrolysis reaction when a flame occurs in a battery module according to an embodiment of the present invention.

[0073] 6 and 7, a module frame 200 according to an embodiment of the present invention may include a vent 900 penetrating an inner surface 200a and an outer surface 200b of the module frame 200.

[0074] The venting unit 900 may be for communicating the inside of the battery module 100, which is sealed by the module frame 200 and the end plate 400, with the outside of the battery module 100. The venting unit 900 may be for discharging heat, gas, flames, etc., generated when an internal fire occurs in the battery module 100, to the outside of the battery module 100.

[0075] The venting portion 900 may have a hole shape that connects an inlet 900a formed on the inner surface 200a of the module frame 200 with an outlet 900b formed on the outer surface 200b.

[0076] The venting portion 900 may be formed on at least one surface of the module frame 200. Here, the module frame 200 may have two open surfaces that are arranged to face each other on the x-axis, which is the length direction of the battery cell stack 120. The module frame 200 may have two surfaces that are arranged to face each other on the y-axis (hereinafter referred to as 'y-axis surfaces') and two surfaces that are arranged to face each other on the z-axis (hereinafter referred to as 'z-axis surfaces'). The two open surfaces of the module frame 200 that face each other on the x-axis may be covered mainly by the end plates 400 or the like.

[0077] The battery modules 100 in the battery pack are arranged with their terminal bus bars 520 facing each other, primarily for HV connection, and any fire or other issues that occur in one battery module 100 are transferred to other adjacent battery modules 100 through an opening, for example, the terminal bus bar opening 400H, formed in the end plate 400. When heat from within the battery module 100 is transferred toward the end plate 400, the external bus bars that electrically connect the adjacent battery modules 100 (HV connection) may melt, causing an internal short circuit and resulting in an additional fire, and thermal runaway may be transferred to the adjacent battery modules.

[0078] However, when the venting portion 900 is formed in the module frame 200, it is possible to minimize the high temperature heat, gas, flames, etc. caused by the battery cells 110 from being discharged through the terminal bus bar opening 400H, thereby minimizing damage to the adjacent battery modules 100 and the HV connection structure of the battery modules 100.

[0079] Here, one surface of the module frame 200 on the y-axis may be a surface extending along the width direction or length direction of the battery cell stack 120. One surface of the module frame 200 on the y-axis may face one surface of one battery cell 110. For ease of explanation, one surface of the module frame 200 on the y-axis may be referred to as a side surface of the module frame 200.

[0080] Also, here, one surface of the module frame 200 on the z-axis may be a surface extending along the stacking direction or length direction of the battery cell stacks 120. One surface of the module frame 200 on the z-axis may face one surface of each of the multiple battery cell stacks 120 arranged side by side along one direction. For ease of explanation, one surface of the module frame 200 on the z-axis may also be referred to as an upper surface or a lower surface (bottom surface or bottom portion).

[0081] 6 and 7, the venting portion 900 is preferably formed on one side of the module frame 200 on the z-axis. This is because, when the venting portion 900 is located on one side of the module frame 200 on the z-axis, the inlet 900a of the venting portion 900 is positioned closer to the multiple battery cells 110 of the battery cell stack 120 than when the venting portion 900 is located on one side of the module frame 200 on the y-axis, and therefore heat, gas, or flames emitted from the multiple battery cells 110 can be quickly discharged to the outside. In this way, the position of the venting portion 900 on the module frame 200 can be determined by the position of one side of the battery cell stack 120 where one sides of the multiple battery cells 110 are positioned side by side.

[0082] The position of the venting portion 900 on the module frame 200 can also be determined by the arrangement of the battery modules 100 within the battery pack. For example, multiple battery modules 100 may be arranged along a first direction (y-axis or x-axis) within the battery pack, but not along a second direction (z-axis). In this case, as shown in FIGS. 6 and 7, if the venting portion 900 is formed on one surface of the module frame 200 along the z-axis (second direction), other adjacent battery modules 100 will not be positioned on the exhaust path extending from the inlet 900a of the venting portion 900 to the outlet 900b, minimizing the impact of exhausted heat, gas, or flame on other battery modules 100. Meanwhile, if the surface on the -z-axis of the two surfaces along the z-axis is the mounting surface connected to the battery pack, the venting portion 900 should be formed on the +z-axis.

[0083] The venting portion 900 may be formed on 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 on only a portion of the surface of the module frame 200. Furthermore, although not shown, the venting portion 900 may be formed on multiple surfaces of the module frame 200.

[0084] The number of the venting portions 900 may be one or more, and when there are a plurality of the venting portions 900, the venting portions 900 are arranged in rows / columns.

[0085] The shapes of the inlet 900a and outlet 900b of the venting unit 900 may be round with curvature as shown in the above drawings, but are not limited to this and may also be circular, elliptical, or polygonal with vertices. Also, since it is preferable that the heat, gas, or flame discharged through the venting unit 900 be 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.

[0086] Meanwhile, the direction from the inlet 900a of the venting portion 900 to the outlet 900b may be the discharge direction in which gas inside the battery module 100 is discharged to the outside. In the above drawings, the direction from the inlet 900a of the venting portion 900 to the outlet 900b is shown to be perpendicular to one surface of the module frame 200 on which the venting portion 900 is formed, but this is not necessarily the case. By changing the positions of the inlet 900a and the outlet 900b of the venting portion 900, the hole structure can be formed so that the discharge direction forms an acute angle with one surface of the module frame 200. By having the hole of the venting portion 900 have such an inclined structure, exposure of the inside of the battery module 100 is minimized and foreign matter floating in the air can be prevented from entering the battery module 100 due to gravity.

[0087] Changing the positions of the inlet 900a and outlet 900b of the venting unit 900 to form an acute angle in the discharge direction can change (adjust) the direction of heat, gas, or flame discharged from the venting unit 900. This increases the length of the discharge path, and the gas discharged through the outlet 900b of the venting unit 900 can have a lower temperature. In addition, if the discharge direction of the venting unit 900 is formed in a direction away from adjacent battery modules 100, the phenomenon of heat transmission between adjacent battery modules 100 can be minimized.

[0088] When there are multiple venting portions 900, the exhaust directions of the multiple venting portions 900 may be the same or different from each other. When the multiple venting portions 900 are formed so that the exhaust directions are different from each other, gases exhausted from the venting portions 900 can be diffused in various directions to a wider space outside the battery module 100. This allows gases to be quickly exhausted from the battery module 100, thereby achieving effects such as preventing heat generation in the battery module 100.

[0089] Meanwhile, when the module frame 200 is provided with a venting unit 900 for communicating the inside and 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 unit 900. Furthermore, when a fire occurs inside the module frame 200, a phenomenon may occur in which the internal fire is accelerated by the supply of external oxygen along the venting unit 900. Therefore, it is preferable that a separate member for closing the hole be provided in the venting unit 900.

[0090] Referring again to FIGS. 6 and 7, the battery module 100 according to an embodiment of the present invention may include a barrier layer 920 covering the opening of the hole structure of the venting portion 900.

[0091] Here, the term 'barrier layer' is used to describe the form of a film that covers the hole of the venting portion 900, and it should be made clear in advance that it can be expressed by replacing it with words such as cover, plug, hood, lid, cap, or other similar words.

[0092] The barrier layer 920 may be provided in a plate shape to cover the holes of the venting portion 900. The barrier layer 920 may be provided in a pad shape to cover the holes of the venting portion 900. The barrier layer 920 may be disposed to cover the inlet 900a or the outlet 900b, thereby covering the holes of the venting portion 900.

[0093] The barrier layer 920 may be disposed under one surface of the module frame 200 on which the venting portion 900 is formed. For example, although the barrier layer 920 is shown to be located between the upper surface of the battery cell stack 120 and the upper surface of the module frame 200 in FIG. 6, this is not necessarily the case. If the venting portion 900 is formed on the side surface of the module frame 200, the barrier layer 920 may be disposed between the side surface of the battery cell stack 120 and the side surface of the module frame 200. Here, for ease of assembly, the barrier layer 920 may be attached to the inner surface 200a of the module frame 200, but this is not necessarily the case.

[0094] Meanwhile, the barrier layer 920 generally closes the hole of the venting portion 900 to prevent external oxygen, dust, impurities, etc. from entering the inside of the battery module 100, but can open the hole of the venting portion 900 in the event of an internal fire in the battery module 100.

[0095] The barrier layer 920 can be made of a material that can withstand high temperature and pressure for a certain period of time. For example, the barrier layer 920 can be made of heat-resistant plastic, carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), a mica-based material, or a ceramic-based material. The barrier layer 920 can also be an extruded material that can withstand high temperature and pressure for a certain period of time. As another example, the barrier layer 920 can be a silicone pad made of silicone.

[0096] The barrier layer 920 may include a material that melts due to the internal temperature of the module frame 200. The barrier layer 920 may include a material that melts due to heat, hot gas, or sparks emitted from the battery cells 110. The barrier layer 920 may be made of a material having a melting point below a predetermined range. For example, the barrier layer 920 may include a thermoplastic polymer resin having a melting point of approximately 200°C or less. More specifically, the barrier layer 920 may be made of a material having a melting point of approximately 100°C or more and 200°C or less, such as polyethylene or polypropylene.

[0097] The barrier layer 920 may also include a material for mitigating ignition in the event of an internal fire within the battery module 100. For example, the barrier layer 920 may include a fire extinguishing agent. If the barrier layer 920 includes a 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. When an internal fire within the battery module 100 occurs, the fire extinguishing agent may generate carbon dioxide and water vapor through a pyrolysis reaction. The generated carbon dioxide and water vapor can suppress the fire by preventing external oxygen from entering the battery module 100. The fire extinguishing agent can absorb heat generated within the battery module by performing a pyrolysis reaction, which is an endothermic reaction, and can also block the external supply of oxygen by generating carbon dioxide and water vapor. This effectively slows the flame and heat propagation speed within the battery module 100, thereby improving the safety of the battery module.

[0098] The barrier layer 920 may contain one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates. More specific examples of fire extinguishing agents include sodium bicarbonate (NaHCO), potassium bicarbonate (KHCO), ammonium phosphate (NHHPO), and a mixture of potassium bicarbonate (KHCO) and urea ((NH)CO). When the barrier layer 920 contains potassium bicarbonate (KHCO), potassium carbonate (KCO), water vapor (H2O), and carbon dioxide (CO2) are generated through the thermal decomposition of potassium bicarbonate. The generated water vapor can neutralize the flame inside the battery module 100, and the generated carbon dioxide can block the flame from contacting oxygen and the like. However, the fire extinguishing agent of this embodiment is not limited thereto, and any material that performs a fire extinguishing function can be used.

[0099] As such, the barrier layer 920 can be provided by being manufactured from a material having the above-mentioned physical properties, but can also be provided by being manufactured from a material having multiple physical properties or a composite of materials having each physical property. For example, the barrier layer 920 can be provided by being manufactured from a material that can withstand a high-pressure environment for a certain period of time and has a melting point of about 200°C or less. As another example, the barrier layer 920 can be provided from a silicone pad containing a fire-extinguishing agent. As yet another example, the barrier layer 920 can be provided from a thermoplastic polymer resin containing a fire-extinguishing agent.

[0100] If a flame, gas, or spark occurs inside the battery module 100, specifically in some battery cells 110, the barrier layer 920 around the ignition site may be physically torn or chemically melted by heat or pressure, penetrating, thereby opening a hole in the venting portion 900. The heat, gas, or spark inside the battery module 100 is released through the opened venting portion 900, mitigating the ignition of the battery module 100. The process of opening the barrier layer 920 may involve an endothermic reaction, and the barrier layer 920 absorbs internal heat, thereby slightly lowering the temperature inside the battery module 100. The heat, gas, and the like released to the outside of the venting portion 900 through the endothermic reaction of the barrier layer 920 lose energy to an extent that they cannot affect adjacent battery modules 100, and the sparks lose energy and turn into particles, preventing them from promoting thermal runaway in adjacent battery modules 100. Meanwhile, the above description of the effect of the barrier layer 920 has focused on the barrier layer 920 being opened through a chemical reaction. However, even when the barrier layer 920 is physically opened by pressure or the like, the kinetic energy of the gas or sparks inside the barrier layer 920 is reduced. Therefore, the heat, gas, etc. released outside the venting portion 900 loses energy to the extent that it cannot affect the adjacent battery modules 100, and the sparks lose energy and turn into particles, preventing them from promoting thermal runaway in the adjacent battery modules 100.

[0101] The barrier layer 920 opens only when heat or pressure exceeding a predetermined range is applied, so that only the vents 900 located around the area where the fire occurred are individually opened. Since gas is discharged from the open vents 900 and additional oxygen is prevented from entering the other closed vents 900, the fire inside the battery module 100 can be extinguished more quickly.

[0102] 7(a), if the barrier layer 920 is not provided, external oxygen may easily enter the battery module 100 through the vent 900. If a fire occurs inside the battery module 100, the external oxygen flowing in through the vent 900 amplifies the internal flame, accelerating continuous fires.

[0103] 7(b), when a barrier layer 920 is provided, a first portion of the barrier layer 920 located above the first battery cell 110 where a fire has occurred is opened, and only the first vent 900 corresponding to the first portion of the vent 900 is open. That is, a second portion of the barrier layer 920 located above the second battery cell 110 where a fire has not occurred is not opened, and the second vent 900 corresponding to the second portion of the vent 900 may be closed. In this way, because only some of the vents 900 are closed by the barrier layer 920, external oxygen can be blocked from entering the battery module 100. As a result, unlike in FIG. 7(a), the amplification of a fire or the like generated inside the battery module 100 by the inflowing oxygen can be suppressed.

[0104] FIG. 8 is a cross-sectional view showing a battery module according to another embodiment of the present invention.

[0105] Referring to FIG. 8, the barrier layer 920 of this embodiment may be provided to fill the hole of the venting portion 900 .

[0106] Specifically, the barrier layer 920 may be provided in a plug-like form that fills the internal space of the hole of the venting portion 900, as shown in FIG. 8(a). The barrier layer 920 may also be provided in a form that combines a plug-like form that fills the hole of the venting portion 900, as shown in FIG. 8(b), and a layer-like form as shown in FIGS. 6 and 7. When the barrier layer 920 is provided as shown in FIG. 8(b), the space occupied by the barrier layer 920 inside the battery module 100 is the same. However, since two barrier layers 920 must be opened to open the venting portion 900 of the battery module 100, the fire suppression effect of the barrier layer 920 should be further enhanced. Here, the plug-like barrier layer 920 that fills the hole of the venting portion 900 may be referred to as a first barrier layer, and the layer-like barrier layer 920 formed below the venting portion 900 may be referred to as a second barrier layer. In this case, the first barrier layer may be composed of multiple barrier layers that fill the interiors of multiple venting portions 900. Here, the plug form and the layer form may be integrally configured in a combined state, but this is not necessarily the case, and they may be provided individually in a separated state.

[0107] 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 be packed with a battery management system (BMS) for managing the temperature and voltage of the battery, a cooling device, and the like.

[0108] The battery module and the battery pack including the same 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 can be applied to various devices that can use the battery module and the battery pack including the same, which also fall within the scope of the present invention.

[0109] 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 fall within the scope of the present invention. [Explanation of symbols]

[0110] 100: Battery module 110: Battery cell 111, 112: Electrode leads 120: Battery cell stack 200:Module frame 300: Busbar frame 400: End plate 400H: Terminal bus bar opening 510: Busbar 520: Terminal bus bar 800: Insulation cover 900: Venting section 920: Barrier layer

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 and having an interior surface and an exterior surface; and an end plate coupled to the module frame and covering a front surface or a rear surface of the battery cell stack; The module frame has a plurality of hole-shaped vents that define an inlet formed on the inner surface and an outlet formed on the outer surface, the hole of the venting portion is covered with a barrier layer, a barrier layer provided on the inner surface of the module frame so as to cover an upper surface of the battery cell stack, and the barrier layer corresponds to a large number of hole-shaped venting portions arranged across the entire upper surface of the module frame in correspondence with the battery cell stack having a plurality of the battery cells.

2. The battery module of claim 1 , wherein the barrier layer comprises a material having a melting point of about 200° C. or less.

3. 3. The battery module according to claim 1, wherein the barrier layer includes a heat-resistant plastic, a carbon fiber reinforced plastic (CFRP), a glass fiber reinforced plastic (GFRP), a mica-based material, a ceramic-based material, or silicon.

4. The battery module according to claim 1 or 2, wherein the barrier layer contains one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

5. The battery module according to claim 1 , wherein the barrier layer is positioned between the battery cell stack and one surface of the module frame on which the vent is formed.

6. The battery module according to claim 1 , wherein the barrier layer fills an inner space of the hole of the vent portion.

7. 3. The battery module of claim 1, wherein the barrier layer includes a first barrier layer that fills an internal space of the hole of the vent, and a second barrier layer that is positioned between the battery cell stack and one surface of the module frame on which the vent is formed.

8. When the direction in which the plurality of battery cells are stacked is defined as a stacking direction, The battery module of claim 1 , wherein the vent is formed on one surface of the module frame extending along the stacking direction.

9. The battery module according to claim 1 , wherein the vent is formed on an upper surface of the module frame.

10. The direction of discharge of the vent forms an acute angle with one surface of the module frame on which the vent is formed, The battery module according to claim 1 , wherein the discharge direction of the venting portion is a direction from the inlet to the outlet.

11. the plurality of battery cells includes a first battery cell and a second battery cell; When a first portion of the barrier layer corresponding to a first vent formed at a position corresponding to the first battery cell is opened, The battery module of claim 1 , wherein a second portion of the barrier layer corresponding to a second vent formed at a position corresponding to the second battery cell is not opened.

12. A battery pack comprising at least one battery module according to claim 1 or 2.

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