Battery module and battery pack including the battery module

Abstract

To provide a battery module.SOLUTION: A battery module according to 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.SELECTED DRAWING: Figure 4

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, filed on July 7, 2021, and all the contents disclosed in the literature of the 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 specifically, to a battery module with enhanced safety and a battery pack including the battery module.

Background Art

[0003] Due to the technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source has been rapidly increasing. Accordingly, many studies on secondary batteries that can meet various requirements have been conducted.

[0004] Secondary batteries have attracted much attention not only as an energy source for mobile devices such as mobile phones, digital cameras, and laptop computers, but also as an energy source for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0005] Recently, there has been an increasing need for medium - sized or large - sized module - structured battery packs that aggregate battery modules in which a large number of secondary batteries are connected in series / parallel, starting from the utilization of secondary batteries as an energy storage source and the necessity for large - capacity secondary battery structures. A battery pack mainly comprises at least one battery module composed of at least one battery cell, and other components are added using at least one battery module. Since the battery cells constituting the battery module are secondary batteries capable of charge and discharge, such high - output large - capacity secondary batteries generate a large amount of heat during the charge and discharge process.

[0006] FIG. 1 is a diagram showing an exploded perspective view of a conventional battery module. FIG. 2 is a diagram showing how a thermal runaway phenomenon transitions during internal ignition of a conventional battery module.

[0007] Referring to FIGS. 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 the like.

[0008] The battery cell stack 12 may be located within a structure sealed by the connection of the frame 20 and the end plates 40. At this time, the frame 20 may have an empty internal space like the A-A cross-sectional view of FIG. 1, and the battery cells 11 may be stacked and located in one direction in the empty internal space of the frame 20 as shown in FIG. 2.

[0009] On the other hand, since the plurality of battery cells 11 are not isolated from each other within the frame 20 and are densely located in one space, even if a thermal runaway phenomenon occurs in only one of the plurality of battery cells 11 existing inside the frame 20 due to reasons such as overcharging, the thermal runaway phenomenon will rapidly transfer to other adjacent battery cells 11 and the like.

[0010] Furthermore, since the plurality of battery modules 10 in the battery pack are arranged such that at least two end plates 40 face each other, when heat, gas, or flame generated within the battery module 10 is discharged to the outside of the battery module 10, it can also affect the performance and stability of the plurality of battery cells 11 in the adjacent other battery modules 10.

[0011] Therefore, it is necessary to develop a battery module 10 with improved durability and safety by effectively delaying the thermal wave speed during internal ignition of the battery module 10 and preventing the generated heat, gas, or flame from being rapidly discharged to the outside of the battery module 10. SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0012] The problem to be solved by the present invention is to provide a battery module that prevents the thermal runaway phenomenon from transferring between battery cells when a fire ignition phenomenon 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-described problems, and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problems

[0014] A battery module according to an 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. At least one venting portion that penetrates 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 on which the venting portion is formed and the battery cell stack.

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

[0016] The barrier layer may be positioned under the refractory layer.

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

[0018] The barrier layer may cover the hole of the sub-venting portion.

[0019] The barrier layer includes a protrusion that partially protrudes from one surface of the barrier layer, and the protrusion may be inserted into the sub-venting portion.

[0020] At least a part of the bending portion and the sub-bending portion may overlap in the length direction of the battery module.

[0021] At least a part of the bending portion and the sub-bending portion may overlap in the width direction of the battery module.

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

[0023] The refractory layer includes a first refractory layer and a second refractory layer, and the first refractory layer may be located closer to the barrier layer than the second refractory layer.

[0024] At least one first sub-bending portion may be formed in the first refractory layer, and at least one second sub-bending portion may be formed in the second refractory layer.

[0025] At least a part of the first sub-bending portion and the second sub-bending portion may overlap in the length direction of the battery module.

[0026] At least a part of the first sub-bending portion and the second sub-bending portion may overlap in the width direction of the battery module.

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

[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, SUS (Stainless Use Steel), or clad metal.

[0030] The battery pack according to another embodiment of the present invention includes the battery module described above.

Advantages of the Invention

[0031] According to the embodiment, when a fire ignition phenomenon occurs in the battery module, gases and the like can be quickly discharged to the outside of the battery module through the holes of the module frame, thereby preventing a continuous thermal runaway phenomenon inside the battery module.

[0032] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Additional Item 1] A battery cell laminate in which a plurality of battery cells are stacked in one direction, A module frame that houses the battery cell laminate, the module frame having an inner surface and an outer surface, A battery module including: On one surface of the module frame, at least one venting portion penetrating the inner surface and the outer surface is formed, A battery module, wherein a cover layer including a barrier layer and a refractory layer is located between the one surface of the module frame where the venting portion is formed and the battery cell laminate. [Additional Item 2] The battery module according to Additional Item 1, wherein the one surface of the module frame is the upper surface of the module frame. [Additional Item 3] The battery module according to Additional Item 1, wherein the barrier layer is located under the refractory layer. [Additional Item 4] The battery module according to Additional Item 1, wherein at least one sub-venting portion is formed in the refractory layer. [Additional Item 5] The battery module according to Additional Item 4, wherein the barrier layer covers the holes of the sub-venting portion. [Additional Item 6] The barrier layer includes protrusions that partially protrude from the one surface of the barrier layer, and the protrusions are inserted into the sub-bending portion. The battery module according to claim 4. [Additional Claim 7] At least a part of the bending portion and the sub-bending portion overlap in the length direction of the battery module. The battery module according to claim 4. [Additional Claim 8] At least a part of the bending portion and the sub-bending portion overlap in the width direction of the battery module. The battery module according to claim 4. [Additional Claim 9] The holes in the sub-bending portion or the bending portion form an acute angle with the one surface of the module frame. The battery module according to claim 4. [Additional Claim 10] The refractory layer includes a first refractory layer and a second refractory layer. The first refractory layer is located closer to the barrier layer than the second refractory layer. The battery module according to claim 1. [Additional Claim 11] At least one first sub-bending portion is formed in the first refractory layer. At least one second sub-bending portion is formed in the second refractory layer. The battery module according to claim 10. [Additional Claim 12] At least a part of the first sub-bending portion and the second sub-bending portion overlap in the length direction of the battery module. The battery module according to claim 11. [Additional Claim 13] At least a part of the first sub-bending portion and the second sub-bending portion overlap in the width direction of the battery module. The battery module according to claim 11. [Additional Claim 14] The barrier layer includes a substance having a melting point of about 300°C or lower. The battery module according to claim 1. [Additional Claim 15] The battery module according to claim 1, wherein the barrier layer contains one or more fire extinguishing agents selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates. [Claim 16] The battery module according to claim 1, wherein the refractory layer contains aluminum, SUS (Stainless Use Steel), or clad metal. [Claim 17] A battery pack including the battery module according to any one of claims 1 to 16.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0034] Hereinafter, with reference to the attached drawings, it will be described in detail so that those having ordinary knowledge in the technical field to which the present invention belongs can easily implement various embodiments of the present invention. The present invention can be embodied in various different forms other than those described below, and the scope of the present invention is not limited by the embodiments described here.

[0035] To clearly explain the present invention, parts that are not relevant to the explanation will be omitted, and the same reference numerals will be assigned to the same or similar components throughout the specification.

[0036] Also, since the size and thickness of each configuration shown in the drawings are arbitrarily enlarged or reduced for the convenience of explanation, it is obvious that the content of the present invention is not limited to what is illustrated. In the following drawings, the thickness of each layer is enlarged to clearly represent various layers and regions. And in the following drawings, for the convenience of explanation, the thickness of some layers and regions is exaggerated.

[0037] Also, when a part such as a layer, film, region, or plate is described as being "on" or "above" another part, this should be interpreted to include not only the case where the corresponding part such as the layer, film, region, or plate is directly above the other part, but also the case where there are other parts in between. Conversely, when the corresponding part such as the layer, film, region, or plate is described as being "directly above" another part, it can mean that there are no other parts in between. Also, 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" in the direction opposite to gravity. On the other hand, similar to the description of being "on" or "above" another part, the description of being "under" or "below" another part can also be understood by referring to the above-mentioned content.

[0038] Also, since the upper surface / lower surface of a specific member can be determined to be different depending on the reference direction, throughout the specification, "upper surface" or "lower surface" is defined to mean two surfaces that face each other on the z-axis in the member.

[0039] Also, throughout the specification, when a part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components and may further include other components.

[0040] In addition, throughout the specification, when it is stated as "on a plane", this means when looking at the relevant part from above, and when it is stated as "in a cross-section", this means when looking at a cross-section cut out perpendicularly from the side of the relevant part.

[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. FIG. 5 is a perspective view of a battery cell included in the battery module of FIG. 3.

[0043] Referring to FIGS. 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 along one direction, a module frame 200 that houses the battery cell stack 120, a bus bar frame 300 located on the front surface and / or the rear surface of the battery cell stack 120, an end plate 400 that covers the front surface and / or the rear surface of the battery cell stack 120, and bus bars 510 and 520 attached to the bus bar frame 300.

[0044] Referring to FIG. 5, the battery cell 110 may be provided in a pouch type that can maximize the number of stacked cells per unit area. The battery cell 110 provided in the 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 of a laminate sheet and then heat-sealing the sealing portion of the cell case 114. However, the battery cell 110 does not necessarily have to be provided in the pouch type, and may be provided in a rectangular, cylindrical, or other various forms as long as the storage capacity required by the device to be attached in the future is achieved.

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

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

[0047] The cell case 114 generally has a laminated structure of a resin layer / a metal thin film layer / a resin layer. For example, when the cell case surface is made of an O (oriented)-nylon layer, when stacking a large number of battery cells 110, etc. to form a medium or large-sized battery module 100, there is a tendency to be slippery due to external impact. Therefore, in order to prevent slipping due to external impact and maintain a stable laminated structure of the battery cell 110, etc., an adhesive member such as an adhesive type adhesive such as double-sided tape or a chemical adhesive bonded by a chemical reaction during adhesion is attached to the surface of the cell case 114 to form the battery cell laminate 120.

[0048] The connecting portion 115 may refer to a region extending along the length direction at one end of the cell case 114 where the aforementioned 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 the end of the connecting portion 115. Also, the Terrace portion 116 may refer to a region between the electrode leads 111 and 112 that partially protrude outside the cell case 114 and the cell body 113 located inside the cell case 114 with reference to the edge of the cell case 114.

[0049] The battery cell laminate 120 may be formed by stacking a plurality of electrically connected battery cells 110 along 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 to include both the + / − directions).

[0050] On the other hand, due to the arrangement of the battery cells 110 along one direction, the electrode leads and the like of the battery cells 110 may be located on one surface of the battery cell laminate 120, or on one surface and the other surface facing the one surface. Thus, the surface on which the electrode leads 111, 112, etc. are located in the battery cell laminate 120 may be referred to as the front surface or the rear surface of the battery cell laminate 120. Here, the direction from the front surface to the rear surface of the battery cell laminate 120, or the opposite direction, may be defined as the length direction of the battery cell laminate 120, which may be the x-axis direction. The length direction of the battery cell laminate 120 may be substantially the same as the length direction of the battery cells 110.

[0051] Also, the surface on which the outermost battery cell 110 is located in the battery cell laminate 120 can be referred to as the side surface of the battery cell laminate 120, and the side surfaces of the battery cell laminate 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 impacts. The module frame 200 may house the battery cell stack 120 and the electrical components connected to the battery cell stack 120 within the internal space of the module frame 200. Here, the module frame 200 includes an inner surface and an outer surface, and the internal space of the module frame 200 may be defined by the inner surface.

[0053] The structure of the module frame 200 may be diverse. 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 integrated upper surface, lower surface, and both side surfaces. 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 the structure in which the U-shaped frame and the upper plate are combined, the structure of the module frame 200 may be formed by coupling the upper plate to the upper side of a U-shaped frame that is a metal plate material with the lower surface and both side surfaces combined or integrated, and each frame or plate may be manufactured by press molding. Also, the structure of the module frame 200 may be provided in an L-shaped frame structure in addition to the monoframe or U-shaped frame, or may be provided in various structures not described in the above examples.

[0054] The structure of the module frame 200 may be provided in a form that is open 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, for example, the bus bar frame 300 or the end plate 400 described later, and the front and rear surfaces of the battery cell stack 120 should be able to be protected from external physical impacts and the like through the bus bar frame 300 or the end plate 400 and the like.

[0055] The upper / lower surfaces, front / rear surfaces, and both side surfaces of the module frame 200 can be described based on the content of the battery cell stack 120 described above. Specifically, the upper / lower surfaces of the module frame 200 are two surfaces that face each other on the z-axis, the front / rear surfaces of the module frame 200 are two surfaces that face each other on the x-axis, and the both side surfaces of the module frame 200 can be described as two surfaces that face 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] On the other hand, although not shown, a compression pad may be positioned between the battery cell stack 120 and the inner surface of the module frame 200. At this time, the compression pad may be positioned between the side surface of the battery cell stack 120 and the 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] Also, a thermally conductive resin may be injected between the battery cell stack 120 and the inner surface of the module frame 200, and a thermally conductive resin layer (not shown) may be formed between the battery cell stack 120 and the inner surface of the module frame 200 by the injected thermally conductive resin. At this time, the thermally conductive resin layer may be formed between the lower surface of the battery cell stack 120 and the lower surface (or may be referred to as the bottom surface, bottom part) of the module frame 200.

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

[0059] The bus bar frame 300 may include a material that is electrically insulating. The bus bar frame 300 can limit the contact between other parts such as the battery cell 110 and the like except for the parts where the bus bars 510, 520 are joined to the electrode leads 111, 112, and can prevent an electrical short circuit from occurring.

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

[0061] The end plate 400 may cover the bus bar frame 300 or the bus bars 510 and 520 located on one surface of the battery cell stack 120 and be coupled (joined, sealed, or hermetically sealed) to the module frame 200. Each corner of the end plate 400 may be coupled to the corresponding corner of the module frame 200 by a method such as welding. Also, an insulating cover 700 for electrical 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 and 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, which may include 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 and 520 may be attached to one surface of the bus bar frame 300 and may be for electrically connecting the battery cell stack 120 or the battery cells 110, etc. to an external device circuit. The bus bars 510 and 520 can be protected from external impacts, etc. by being located between the battery cell stack 120 or the bus bar frame 300 and the end plate 400, and the degradation of durability due to external moisture, etc. can be minimized.

[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 the slits formed in the bus bar frame 300 and then be bent and connected to the bus bars 510 and 520. The battery cells 110, etc. that make up the battery cell stack 120 may be connected in series or in parallel by the bus bars 510 and 520.

[0065] On one hand, the bus bars 510 and 520 may include a terminal bus bar 520 for forming an electrical connection between the battery modules 100. In order to connect to other external battery modules 100, at least a part of the terminal bus bar 520 may be exposed outside the end plate 400, and the end plate 400 may be provided with a terminal bus bar opening 400H therefor. The terminal bus bar may be connected to other battery modules 100 or a BDU (Battery Disconnect Unit) through a protrusion exposed through the terminal bus bar opening 400H, and may form an HV (High voltage) connection with them.

[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 LV (Low voltage) connection, and here the LV connection can mean a sensing connection for sensing and controlling the voltage of the battery cell, etc. Voltage information and temperature information of the battery cell 110 may be transmitted to an external BMS (Battery Management System) through the sensing member.

[0067] The sensing member may include a temperature sensor for sensing the temperature inside the battery module, a sensing terminal for sensing the voltage values of the bus bars 510 and 520, a module connector for transmitting the collected data to an external control device and receiving a signal from the external control device, and / or a connecting member for connecting the module connectors.

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

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

[0070] On the other hand, inside the battery module 100 in which the battery cells 110 are stacked at a high density as described above, a fire occurrence phenomenon may appear. When a fire occurrence phenomenon occurs in one battery module 100, heat, gas, or flame of the battery module 100 may be transmitted to the adjacent battery module 100, so a continuous fire occurrence phenomenon may occur between the battery modules 100, and as a result, there has been a problem that the durability and stability of the battery module 100 or the battery pack including the battery module 100 are reduced.

[0071] Therefore, hereinafter, a cover layer 800 and a venting part 900 that can improve the durability and stability of the battery module 100 by eliminating the above-described fire occurrence phenomenon will be described.

[0072] Furthermore, referring to FIGS. 3 and 4, the module frame 200 according to an embodiment of the present invention may include a venting part 900 that penetrates the inner surface and the outer surface of the module frame 200. The venting part 900 may have a hole form that communicates an inlet 900a formed on the inner surface of the module frame 200 and an outlet 900b formed on the outer surface. The venting part 900 may be for communicating the inside of the battery module 100 sealed by the module frame 200, the end plate 400, etc. and the outside of the battery module 100.

[0073] The venting part 900 is provided to discharge heat, gas, or flames generated when ignition occurs inside the battery module 100 to the outside of the battery module 100. The venting part 900 can prevent the continuous occurrence and transfer of the thermal runaway phenomenon by alleviating the internal ignition phenomenon of the module frame 200 and minimizing the increase in pressure or temperature. Specifically, when ignition occurs inside the module frame 200, heat, gas, sparks, flames, etc. generated by the ignition of the battery cell 110 are discharged to the outside of the battery module 100 through the venting part 900, thereby quickly suppressing an internal fire and further alleviating the ignition phenomenon. Also, by discharging heat, gas, etc. through the venting part 900, it is possible to prevent the pressure or temperature inside the battery module 100 from rising excessively, and it is also possible to delay the speed at which thermal runaway transfers in the internal space.

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

[0075] There may be at least one or more venting parts 900 formed on the upper surface of the module frame 200. The greater the number of venting parts 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 parts 900, the venting parts 900 may be arranged in rows along one direction and columns along a direction perpendicular to the one direction. At this time, the venting parts 900 may be formed over the entire surface of one surface of the module frame 200 as in the above-described drawings, etc., but not necessarily so, and may be formed on a part of one surface of the module frame 200.

[0076] The shapes of the inlet 900a and the outlet 900b of the bending portion 900 may be a round shape having a curvature as shown in the above-described drawings and the like, but not necessarily so. The inlet 900a and the outlet 900b of the bending portion 900 may be provided in a circular shape, an elliptical shape, or a polygon having vertices. Further, since it is preferable that the heat, gas, or flame discharged through the bending portion 900 diffuses rapidly outside the battery module 100, the size of the outlet 900b may be provided to be even larger than the size of the inlet 900a.

[0077] On the other hand, the direction from the inlet 900a to the outlet 900b of the bending portion 900 may be a discharge direction in which the gas inside the battery module 100 is discharged to the outside. In the above-described drawings, the direction from the inlet 900a to the outlet 900b of the bending portion 900 is shown to be perpendicular to one surface of the module frame 200 in which the bending portion 900 is formed, but not necessarily so. By changing the positions of the inlet 900a and the outlet 900b of the bending portion 900, a hole structure may be formed such that the discharge direction forms an acute angle with one surface of the module frame 200. By having the hole of the bending portion 900 have an oblique structure in this way, the exposure inside the battery module 100 can be minimized, and the phenomenon in which foreign matter floating in the air enters the battery module 100 due to gravity can be prevented.

[0078] When the discharge direction forms an angle (acute angle) by changing the positions of the inlet 900a and the outlet 900b of the bending portion 900, the direction of the heat, gas, or flame discharged from the bending portion 900 can be switched (adjusted). As a result, the length of the discharge path increases, and the gas and the like discharged through the outlet 900b of the bending portion 900 can have a lower temperature. Further, when the discharge direction of the bending portion 900 is formed in a direction in which the adjacent battery module 100 is not located, the phenomenon in which heat propagates between the adjacent battery modules 100 can also be minimized.

[0079] When there are multiple bending portions 900, the discharge directions of the multiple bending portions 900 may be the same as each other or different from each other. When the discharge directions of the multiple bending portions 900 are formed to be different from each other, gases or the like discharged from the bending portions 900 can diffuse into a wider space outside the battery module 100 in various directions. Thereby, gas discharge from the battery module 100 can be performed quickly, and effects such as preventing heat generation of the battery module 100 can be achieved.

[0080] On the other hand, when, as in the present embodiment, the module frame 200 is provided with the bending portion 900 for communicating the inside and the outside, dust, impurities, etc. outside the module frame 200 may enter the inside of the module frame 200 through the hole structure of the bending portion 900, or external oxygen may be supplied along the bending portion 900 during internal ignition, which may accelerate the thermal runaway phenomenon. In addition, since the temperature and pressure of the gas, spark, etc. discharged through the bending portion 900 of the module frame 200 may be in a very high state, there is a problem that the discharged gas, spark, etc. are transmitted to the adjacent battery module 100, inducing the thermal runaway phenomenon in the adjacent battery module 100.

[0081] Therefore, the bending portion 900 of the present embodiment may be provided with a cover layer 800 that can close the hole before the thermal runaway phenomenon occurs and open the hole when the thermal runaway phenomenon occurs, thereby reducing the temperature and pressure of the gas or the like to be discharged.

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

[0083] Here, since the expression "cover layer" is used to represent the form of a film for closing the hole of the bending portion 900, it is clarified in advance that it can be expressed by changing it to a lid, a hood, a lid, a 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 in which the bending 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 can cover the hole of the bending portion 900 by being disposed so as to cover the inlet 900a. The cover layer 800 may be provided in a plate-like form for covering the hole of the bending portion 900. The cover layer 800 may be provided in a pad form for covering the hole of the bending portion 900.

[0086] The cover layer 800 may include a plurality of 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 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. Considering its position, the barrier layer 810 can be referred to as the first layer, and the refractory layers 820, 830 can be referred to as the second layer. Also, here, the refractory layer may include two or more layers as shown in FIG. 4. For the sake of convenience of explanation, the layer relatively closer to the barrier layer 810 can be referred to as the first refractory layer 820, and the layer located farther away can be referred to as the second refractory layer 830. Or, in terms of its position, the barrier layer 810 can be referred to as the first layer, the first refractory layer 820 can be referred to as the second layer, and the second refractory layer 830 can be referred to as the third layer.

[0087] On one hand, a number of bending portions may be formed in the refractory layers 820 and 830. For the purpose of distinguishing from the bending portion 900 formed in the module frame 200, the bending portions formed in the refractory layers 820 and 830 can be referred to as sub-bending portions 822 and 832. Each of the sub-bending portions 822 and 832 may have an inlet and an outlet, and the inlet may be relatively lower than the outlet. The sub-bending portions 822 and 832 formed in the refractory layers 820 and 830 can guide the gas discharge path so that gases, sparks, etc. generated in the battery cell 110 do not move to other spaces within the battery module 100 and are discharged to the bending portion 900.

[0088] The refractory layers 820 and 830 may be manufactured from a material that can withstand a high-temperature and high-pressure environment for a certain period of time. For example, the refractory layers 820 and 830 may be manufactured using aluminum, SUS (Stainless Use Steel), or clad metal as the material. The refractory layers 820 and 830 may also be an ejecta that can withstand a high-temperature and high-pressure environment for a certain period of time.

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

[0090] The barrier layer 810 may include a material that melts depending on 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 spark released from the battery cell 110. The barrier layer 810 may be manufactured from a substance having a melting point below a predetermined range. The barrier layer 810 may be provided with a substance having a melting point of 300 °C or lower. By way of a specific example, the barrier layer 810 may include a thermoplastic polymer resin having a melting point of about 200 °C or lower. More specifically, the barrier layer 810 may be manufactured from a substance such as polyethylene or polypropylene having a melting point of about 100 °C or higher and 200 °C or lower.

[0091] The barrier layer 810 may include a substance for mitigating the ignition phenomenon in the event of internal ignition of the battery module 100. For example, the barrier layer 810 may include a fire extinguishing agent. When the barrier layer 810 includes a fire extinguishing agent, the battery module 100 can have a self-extinguishing function. Here, the fire extinguishing agent may be a fire extinguishing agent substance in powder form. The fire extinguishing agent can generate carbon dioxide and water vapor through a thermal decomposition reaction during internal ignition of the battery module 100, and the generated carbon dioxide and water vapor can suppress the flame by preventing external oxygen from flowing into the battery module 100. The fire extinguishing agent can absorb the heat generated in the battery module by performing a thermal decomposition reaction that is an endothermic reaction, and can also block the supply of external oxygen by generating carbon dioxide and water vapor. Thereby, the flame and the thermal wave speed inside the battery module 100 can be effectively delayed, and the safety of the battery module can be improved.

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

[0093] Thus, the barrier layer 810 may be manufactured and provided with a substance having the above-described physical properties, but may also be provided as a composite of a substance containing a plurality of physical properties or a substance containing each physical property, etc.

[0094] Hereinafter, the effects caused by providing the cover layer in the battery module of this embodiment will be described in more detail.

[0095] FIG. 6 is a cross-sectional view taken along the cutting line B-B of FIG. 3. FIG. 7 is a cross-sectional view taken along the cutting line C-C of FIG. 3. FIG. 8 is a view showing the state of internal ignition of the battery module according to 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] Referring to FIGS. 6 and 7, at least a part of the bending portion 900 formed in the module frame 200 and the sub-bending portions 822 and 832 formed in the refractory layers 820 and 830 may overlap in the length direction (x-axis) of the battery module 100. At least a part of the bending portion 900 and the sub-bending portions 822 and 832 may overlap in the width direction (y-axis) of the battery module 100.

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

[0098] When holes or the like formed in the module frame 200 and the refractory layers 820 and 830 partially overlap each other, the path of gas or 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 or the like is discharged, as shown by the arrows in FIGS. 6 and 7, can form an angle with the z-axis. The path through which gas or the like is 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 made longer compared to the case where they correspond to each other. The discharge path of the gas may be made longer than the shortest distance between the upper surface of the battery cell stack 120 and the module frame 200. By making the discharge path of the gas longer, the temperature and pressure of the gas discharged to the outside of the battery module 100 can be made lower, and it can have low energy so as not to affect the adjacent battery modules 100.

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

[0100] Referring to FIG. 8, inside the battery module 100, specifically, when a flame, gas, or spark occurs in some of the battery cells 110, the barrier layer 810 around the ignition phenomenon may be physically broken or chemically melted and penetrated by heat or pressure, whereby the bending portion 900 and the sub-bending portions 822 and 832 may be opened. Heat, gas, or spark inside the battery module 100 can be discharged through the opened bending portion 900 and sub-bending portions 822 and 832, and the ignition phenomenon of the battery module 100 can be alleviated. Here, the process of the barrier layer 810 being penetrated, that is, opened, may be accompanied by an endothermic reaction, and the temperature inside the battery module 100 may be lowered by the barrier layer 810 absorbing the internal heat. Heat, gas, etc. released to the outside of the bending portion 900 through the endothermic reaction of the barrier layer 810 may lose energy so as not to affect the adjacent battery module 100, and the spark may lose energy and change into particles, and may not promote the thermal runaway phenomenon of the adjacent battery module 100.

[0101] On the one hand, in the above, regarding the effect of the barrier layer 810, the description has centered on the barrier layer 810 being released through a chemical reaction. However, even when the barrier layer 810 is physically released by pressure or the like, the kinetic energy of the movement of gas or sparks will decrease during 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 such an extent that they do not affect the adjacent battery module 100, and the sparks lose energy and change into particles. Thus, the thermal runaway phenomenon of the adjacent battery module 100 can be suppressed.

[0102] On the other hand, since the barrier layer 810 can be opened only when heat or pressure above a predetermined range is applied, only the barrier layer 810 located around where the ignition phenomenon appears can be individually opened. The barrier layer 810 can prevent the promotion of the thermal runaway phenomenon due to the inflow of further oxygen by opening only a part of the large number of bending portions 900 and sub-bending portions 822, 832.

[0103] Specifically, when an ignition phenomenon occurs in the first battery cell 110a, the first part 810a of the barrier layer 810 corresponding to the first battery cell 110a is opened, thereby discharging the gas, flame, etc. generated in the first battery cell 110a. At this time, the second part 810b of the barrier layer 810 located above the second battery cell 110b in which no ignition phenomenon occurs in the battery module 100 is not opened, and the first sub-bending portion 822 corresponding to the second part 810b may be in a closed state. In this way, by maintaining the closed state of the barrier layer 810 in other parts where no ignition phenomenon occurs, the inflow of external oxygen into the battery module 100 can be blocked, and the amplification of the flame, etc. generated inside the battery module 100 by the inflowing oxygen can be suppressed.

[0104] On the one hand, the barrier layer 810 may include protrusions 812 that partially protrude from one side of the barrier layer 810. The protrusions 812 may be formed on the upper surface of the barrier layer 810. At this time, the size of the protrusions 812 may be similar to or smaller than the size of the first sub-venting portion 822, so that the protrusions 812 may be inserted into the first sub-venting portion 822 formed in the first refractory layer 820. The outer shape of the protrusions 812 may correspond to the inner shape of the first sub-venting portion 822, whereby the holes in the first sub-venting portion 822 may be closed by the protrusions 812. When the protrusions 812 of the barrier layer 810 are provided to fill the holes in the first sub-venting portion 822 of the first refractory layer 820, the region of the barrier layer 810 where the protrusions 812 are formed will have a thick thickness. When the protrusions 812 are formed in the barrier layer 810, the space occupied by the barrier layer 810 inside the battery module 100 is the same, but since the thick barrier layer 810 must be opened for the battery module 100 to release gas or the like to the outside, the fire suppression effect by the barrier layer 810 may be greater. However, this is not necessarily the case, and it is also possible that no protrusions 812 are formed in the barrier layer 810 and the barrier layer 810 is provided with a flat shape.

[0105] On the other hand, the battery module 100 described above may be included in a battery pack. The battery pack may include one or more battery modules according to this embodiment, and may have a structure in which a battery management system (BMS) for managing the temperature, voltage, etc. of the battery and a cooling device are added and packed.

[0106] The battery module and the battery pack including the battery module are applicable to various devices. Such devices are applicable to transportation means such as electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto, and is applicable to various devices in which the battery module and the battery pack including the battery module are used, and this also belongs to the scope of rights of the present invention.

[0107] In the above, the preferred embodiments of the present invention have been described in detail. However, the scope of the rights 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 rights of the present invention.

Explanation of Reference Numerals

[0108] 10 Battery module 11 Battery cell 12 Battery cell laminate 20 Frame 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 Connecting part 116 Part 120 Battery cell laminate 200 Module frame 300 Bus bar frame 400 End plate 400H Terminal bus bar opening 510 Bus bar 520 Bus bar 700 Insulation cover 800 Cover layer 810 Barrier layer 810a First part 810b Second part 812 Protrusion 820 (First) refractory layer 822 (First) sub-bending part 830 Second refractory layer 832 (Second) sub-bending part 900 Bending part 900a Inlet 900b Outlet Cutting line B-B Outside of BMS Cutting line C-C

Claims

[Claim 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 positioned between the one surface of the module frame on which the vent is formed and the battery cell stack.

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