Battery module, battery pack and vehicle comprising the battery module

Abstract

A battery module according to the present invention comprises a plurality of battery cells, a case that accommodates the plurality of battery cells in an internal space, a side wall portion disposed between the battery cells, and a protective member having a cover portion disposed to cover the upper portion of the battery cells and connected to the side wall portion.

Description

Technology Field

[0001] The present invention relates to a battery module, a battery pack including such a battery module, and an automobile. More specifically, it relates to a battery module having a structure capable of preventing the spread of thermal runaway when thermal runaway occurs in a battery cell, a battery pack including such a battery module, and an automobile. Background Technology

[0002] As the demand for portable electronic products such as smartphones, tablet PCs, and smartwatches increases significantly and electric vehicles become increasingly widespread, research on batteries installed in them, particularly secondary batteries capable of repeated charging and discharging, is actively underway.

[0003] Currently commercialized rechargeable batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to charge and discharge freely with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0004] These lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. A lithium secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with the positive and negative active materials respectively, are arranged with a separator in between, and an outer casing, namely a battery case, that seals and encloses the electrode assembly together with the electrolyte. Generally, lithium secondary batteries can be classified according to the shape of the outer casing into can-type secondary batteries, in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of aluminum laminate sheets.

[0005] Recently, secondary batteries are widely used for driving or energy storage not only in small devices such as portable electronic devices but also in medium-to-large devices such as electric vehicles and Energy Storage Systems (ESS). A single battery module can be formed by housing multiple such secondary batteries together inside a module case while electrically connected. In this case, each secondary battery included in a single battery module can be referred to as a battery cell. Furthermore, multiple such battery modules can be connected to form a single battery pack.

[0006] Meanwhile, since battery cells involve chemical reactions during charging and discharging, their performance may degrade if used in environments higher than the optimal temperature; furthermore, if thermal control is not maintained at the appropriate temperature, there is a constant risk of unexpected ignition or explosion. Additionally, battery modules are structured to house these battery cells intensively within a module frame. Therefore, if thermal runaway occurs in any single battery cell, the emitted high-temperature gases and flames can spread to adjacent cells, potentially leading to a chain reaction of explosions, making this situation extremely dangerous.

[0007] In particular, in the case of a battery module equipped with cylindrical battery cells, if thermal runaway occurs in any one battery cell, heat can propagate to adjacent battery cells. Additionally, high-temperature gases or flames ejected from the battery cells can transfer to the upper surface of adjacent battery cells. Specifically, electrode terminals and busbars connected to the electrode terminals may be placed on the upper surface of the battery cells; if flames or ejected substances transfer to this area, a chain reaction of thermal runaway may occur. Therefore, it is necessary to develop a battery module capable of protecting adjacent battery cells in the event of thermal runaway in a battery cell. The problem to be solved

[0008] The problem that the present invention aims to solve is to provide a battery module with improved safety and reliability by effectively preventing the propagation of thermal runaway between battery cells during thermal runaway of the battery module.

[0009] Another technical objective of the present invention is to provide a battery pack including a battery module of an improved structure, and a vehicle including the battery pack.

[0010] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below. means of solving the problem

[0011] To solve the above objective, a battery module according to the present invention may include: a plurality of battery cells; a case accommodating the plurality of battery cells in an internal space; and a protective member having a side wall portion disposed between the battery cells and a cover portion disposed to cover the upper portion of the battery cells and connected to the side wall portion.

[0012] According to the present invention, each of the side wall portion and the cover portion is characterized by including a plate-shaped insulation pad and a frame coupled to the edge of the insulation pad to support the insulation pad.

[0013] In addition, according to the present invention, the cover portion has a bending line and is characterized by being able to be bent along the bending line.

[0014] In addition, according to the present invention, the cover portion is characterized by being separated into a plurality of parts.

[0015] In addition, according to the present invention, the protective member comprises a pair of cover portions, wherein one of the pair of cover portions is positioned to cover the upper portion of battery cells arranged on one side of the side wall portion, and the other of the pair of cover portions is positioned to cover the upper portion of battery cells arranged on the other side of the side wall portion.

[0016] In addition, according to the present invention, the protective member is characterized by being provided with an expansion portion that expands by heat.

[0017] In addition, according to the present invention, the expansion portion is characterized by being configured to push the cover portion upward when expanded.

[0018] In addition, according to the present invention, the surface of the protective member is characterized by having a fire-resistant layer.

[0019] And, the present invention provides a battery pack characterized by comprising at least one battery module according to the embodiments described above.

[0020] In addition, the present invention provides a vehicle characterized by including at least one battery module according to the above-described embodiment. Effects of the invention

[0021] According to the present invention, when abnormal conditions such as thermal runaway occur in a battery cell, the battery cell can be protected from flames or high-temperature gases. Accordingly, the spread of thermal runaway between battery cells can be prevented or suppressed.

[0022] In particular, according to the present invention, high-temperature gases ejected from a battery cell can be guided by a cover portion and discharged through a venting area. In other words, the propagation of high-temperature gases into the internal space of a battery module can be prevented or suppressed, and thus, the spread of thermal runaway within the battery module can be prevented.

[0023] In particular, in the case of electric vehicles, by suppressing or delaying the propagation of thermal runaway between battery cells, sufficient time can be secured for occupants to escape or continue driving.

[0024] In addition to the above, the present invention may have various other effects, which are described in each embodiment, or effects that can be easily inferred by those skilled in the art, etc., will be omitted. Brief explanation of the drawing

[0025] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a schematic exploded view of a battery module according to one embodiment of the present invention. Figure 2 is a perspective view of the battery cell shown in Figure 1. FIG. 3 is a schematic perspective view of the protective member shown in FIG. 1. Figure 4 is a view of the battery cell and protective member in the direction of the arrow (V) in Figure 1. Figure 5 is a diagram illustrating the behavior of a protective member during thermal runaway of a battery cell. FIG. 6 is a drawing for explaining a protective member according to another embodiment of the present invention. FIG. 7 is a perspective view illustrating a protective member according to another embodiment of the present invention. FIG. 8 is a perspective view of a protective member according to another embodiment of the present invention. FIG. 9 is a drawing for explaining the behavior of the protective member shown in FIG. 8. FIG. 10 is a drawing for explaining a protective member according to another embodiment of the present invention. FIG. 11 is a drawing for explaining a protective member according to another embodiment of the present invention. FIG. 12 is a schematic perspective view of a protective member according to another embodiment of the present invention. FIG. 13 is a cross-sectional perspective view illustrating a cylindrical battery cell. FIG. 14 is a drawing for explaining a battery pack according to one embodiment of the present invention. FIG. 15 is a drawing for explaining an automobile according to one embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0027] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0028] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back may be used in this specification, these terms are used merely for convenience of explanation and may vary depending on the location of the object or the position of the observer, it is obvious to those skilled in the art of the present invention.

[0029] In an embodiment of the present invention, the X-axis direction shown in the drawing may mean the left-right direction, the Y-axis direction may mean the front-back direction perpendicular to the X-axis direction on the horizontal plane (XY plane), and the Z-axis direction may mean the up-down direction (vertical direction) perpendicular to both the X-axis direction and the Y-axis direction.

[0030] Additionally, in this specification, terms indicating direction such as internal or external may be used; unless otherwise specifically stated, internal refers to the direction toward the central part of the battery module, and external refers to the opposite direction.

[0031] In addition, this specification includes various embodiments. Detailed descriptions of identical or similar parts regarding other embodiments are omitted, and the description focuses on the parts where each embodiment differs.

[0033] A battery module according to the present invention may include a plurality of battery cells. A battery cell may include an electrode assembly, a cell case housing the electrode assembly, and an electrolyte. The battery cell may be classified into a can-type secondary battery and a pouch-type secondary battery. In the embodiments described below, the description will be based on a can-type secondary battery having a cylindrical shape. However, the application of the present invention is not limited to cylindrical secondary batteries.

[0035] FIG. 1 is a schematic exploded perspective view of a battery module according to an embodiment of the present invention. FIG. 2 is a perspective view of a battery cell shown in FIG. 1. FIG. 3 is a schematic perspective view of a protective member shown in FIG. 1. FIG. 4 is a view of the battery cell and the protective member in the direction of the arrow (V) in FIG. 1. FIG. 5 is a drawing for explaining the behavior of the protective member during thermal runaway of the battery cell.

[0037] Referring to FIGS. 1 to 5, a battery module (1000) according to one embodiment of the present invention may include a battery cell (100), a case (200), and a protective member (300).

[0038] The battery cell (100) can be classified into a can type and a pouch type depending on the shape of the case that accommodates the electrode assembly. In particular, in the present embodiment, the battery cell (100) may be a can-type secondary battery, and in particular, may be a cylindrical battery cell.

[0039] A battery cell (100) may include a battery housing (20), an electrode assembly housed inside the battery housing, and an electrolyte. The battery housing (20) may be formed in a hollow cylindrical shape. One end of the battery housing (20), for example, the lower end, may be open, and this opening may be sealed by a housing cover. An electrode terminal (50) electrically connected to the electrode assembly may be provided on the upper surface of the battery housing (20). Additionally, a venting line (VL) may be provided on the upper or lower surface of the battery housing (20). The venting line (VL) is intended to discharge gas and flames inside the battery cell by rapidly damaging a part of the battery housing during thermal runaway of the battery cell. The battery cells (100) may be provided in multiple numbers and may be arranged in rows in the horizontal and vertical directions.

[0040] The specific configuration of the above battery cell (100) will be described later.

[0042] A case (200) may be intended to accommodate a plurality of battery cells (100) inside. Specifically, the case (200) may include a main body (210) and a top plate (220). The main body (210) may be formed in a roughly rectangular shape, and its top portion may be open. A space is formed inside the main body (210), and a plurality of battery cells (100) may be placed in this space. At this time, the battery cells (100) may be arranged in rows in the horizontal and vertical directions. The main body (210) may include metal and / or plastic materials. The top plate (220) may be formed in a plate shape. The top plate (220) may be attached to the top of the main body (210) to seal the interior of the main body (210). The top plate (220) may include metal and / or plastic materials. For example, the top plate (220) and the main body (210) may be made of the same material, and in particular, may be made of aluminum. Aluminum may have excellent lightness and strength. If the top plate (220) and the main body (210) are constructed of aluminum, rapid heat dissipation to the outside may be possible in the event of thermal runaway of the battery cell. The main body (210) and the top plate (220) may be joined together. At this time, various fastening methods such as welding or bolting may be used. However, the present invention is not limited by the specific material, shape, or joining method of such case (200).

[0043] According to one embodiment, although not shown in the drawings, one side of the case (200), such as the upper surface (top plate) or the lower surface, may include at least one venting area through which venting gas discharged from the battery cell (100) is ejected. For example, the venting area may be either a venting hole or a preliminary break line. According to one embodiment of the present invention, a venting area may be provided on the top plate (220) to induce directional venting toward the upper side of the battery module (1000).

[0045] The protective member (300) may be for blocking heat transfer between battery cells (100). Specifically, the protective member (300) may include a side wall portion (310) and a cover portion (320).

[0046] The side wall portion (310) may have a flat shape overall. The side wall portion (310) may be placed inside the case (200). At this time, the side wall portion (310) may be placed between the battery cells (100). For example, a plurality of cells (100) may be arranged in rows in the left-right (X-axis direction) and front-back (Y-axis direction) directions. At this time, the side wall portion (310) may be placed between the battery cells (100) arranged in rows in the front-back direction. For example, the side wall portion (310) may be placed between the battery cells (100) in an up-and-down position (Z-axis direction). The side wall portion (310) can block heat transfer between the battery cells (100). In particular, the side wall portion (310) can block heat transfer in the left-right direction (X-axis direction).

[0047] The cover portion (320) may be intended to cover and protect the upper portion of the battery cells (100). Specifically, the cover portion (320) may be formed in a flat plate shape. The cover portion (320) may be connected to the side wall portion (310). At this time, as shown in FIG. 3, the cover portion (320) may be combined in a manner orthogonal to the side wall portion (310). The cover portion (320) may be positioned to cover the upper portion of the battery cells (100). For example, as shown in FIG. 4, the cover portion (320) is positioned horizontally and is arranged to cover the upper portion of the battery cells (100) that are in contact with the side wall portion (310).

[0048] When the battery cell (100) ignites, the cover portion (320) can be lifted upward. Specifically, as shown in FIG. 5, the cover portion (320) covering the top of the battery cell (100) (Fig. 5(a)) can be lifted upward while rotating due to the pressure of the gas ejected from the battery cell (100). At this time, when the end of the cover portion (320) touches the top plate (220) of the case, it can be supported in the form shown in FIG. 5(b). And when the cover portion (320) is supported in this way, the gas ejected from the battery cell (100) can be guided along the cover portion (320) and discharged. For reference, although not shown in the drawings, a venting area (e.g., a venting hole) may be provided on the top plate of the case, and the gas can be discharged to the outside through the venting area along the cover portion (320).

[0049] The above protective member (300) may be provided in multiple numbers. The multiple protective members (300) may be arranged between the rows (rows in the front-rear direction) of the battery cells (100).

[0051] According to the embodiment of the above configuration, the battery cell (100) can be protected by the protective member (300). Specifically, the upper part of the battery cell (100) can be protected by the cover part (320). For example, the cover part (320) can protect the upper part of the battery cell (100) from dust, moisture, and impact. In particular, if thermal runaway occurs in any one of the battery cells (100), gas, flames, and discharges may be ejected from the battery cell (100). At this time, the cover part (320) positioned above the battery cell where thermal runaway occurred can be lifted upward, and in this state, gas, etc. can be discharged along the cover part (320). Thus, it is possible to prevent or suppress the propagation of gas, etc. to other battery cells (100). In addition, the remaining cover parts (320) can protect the battery cell (100) by covering the upper part of the battery cell (100).

[0052] In this regard, an electrode terminal (50) is provided on the upper surface of the battery cell (100), and a bus bar or the like can be connected to the electrode terminal (50). Accordingly, protecting the upper surface of the battery cell (100) may be very important for the stability of the battery module (1000). In this embodiment, the cover portion (320) protects the upper surface of the battery cell (100), thereby improving the stability of the battery module (1000).

[0053] Additionally, heat transfer between adjacent battery cells (100) can be blocked by the side wall portion (310). Therefore, when a battery cell (100) undergoes thermal runaway, the propagation of this thermal runaway to surrounding battery cells can be prevented or suppressed.

[0055] According to the present embodiment, the protective member (300) may include an insulating pad (311, 321) and a frame (312, 322). Specifically, as shown in FIG. 3, the side wall portion and the cover portion may each be configured to include an insulating pad (311, 321) and a frame (312, 322).

[0057] The insulation pads (311, 321) are intended to block heat transfer between battery cells (100) and to protect the battery cells (100). The insulation pads (311, 321) may be composed of a material having thermal insulation properties. For example, the insulation pads (311, 321) may include materials such as MICA, silicone-based materials, and polymer-based materials. The insulation pads (311, 321) may be formed in a plate shape.

[0059] The frame (312, 322) is intended to support the insulation pad (311, 321) and can be attached to the edge of the insulation pad (311, 321). Specifically, the insulation pad (311, 321) has a thin thickness, and due to the characteristics of the material (substance) constituting the insulation pad (311, 321), the rigidity of the insulation pad (311, 321) may be insufficient. Therefore, as shown in FIGS. 3 and 4, if the protective member (300) is formed in an 'L' shape using only the insulation pad (311, 321), it may not be able to maintain its shape. For example, the side wall (310) may not be able to stand upright in the vertical direction and may collapse downward, and accordingly, the position of the cover part (320) connected to the side wall (310) may also deviate from the upper side of the battery cell (100). In this embodiment, the frame (312, 322) is coupled to the insulation pad (311, 321) to support the insulation pad.

[0060] For example, the frame (312, 322) may be formed to be long in one direction. The frame (312, 322) may be provided in multiple numbers and each may be attached to the edge of the insulation pad (311, 321). As shown in FIG. 3, the frame (312, 322) may be attached to the edges on both sides (in the Y-axis direction) of the insulation pad (311, 321). If necessary, the frame may also be attached to the lower edge of the insulation pad (311, 321). The frame (312, 322) may be attached to the insulation pad (311, 321) by means of an adhesive or the like. In particular, in the case of the present embodiment, a groove may be provided in the frame (312, 322) that is formed concavely along its length direction, and the frame may be attached in a manner such that the edge of the insulation pad (311, 321) fits into this groove.

[0061] According to the embodiment of the above configuration, the frame (312, 322) can support the insulation pad (311, 321). In other words, by reinforcing the rigidity that the insulation pad (311, 321) may lack, the protective member (300) can maintain its shape. Therefore, when the protective member (300) is placed in the battery module (1000), the protective member (300) can efficiently protect the battery cell (100) while maintaining its shape.

[0063] FIG. 6 is a drawing for explaining a protective member according to another embodiment of the present invention.

[0064] Referring to FIG. 6, a bend line (CL) may be provided in the cover portion (320A) of the protective member (300). Specifically, the bend line (CL) may be intended to allow the cover portion (320A) to be bent well along the bend line (CL). For example, as shown in FIG. 6, the bend line (CL) can be implemented by forming a 'V'-shaped groove in the cover portion. The bend line (CL) may be provided in the frame of the cover portion (320A), or it may be provided in both the frame and the insulation pad. For convenience of explanation, the cover portion (320A) may be divided into a left part (3201) and a right part (3202) based on the bend line (CL).

[0065] The cover portion (320A) can be lifted by the gas ejected during thermal runaway of the battery cell (100). At this time, as shown in FIG. 6 (b), the cover portion (320A) can be folded along the bending line (CL). In other words, the right part (3202) of the cover portion (320A) can be set up vertically like the side wall portion (310), and the left part (3201) of the cover portion can be positioned horizontally.

[0066] According to the present embodiment, gases ejected from the battery cell (100) can be discharged more smoothly to the outside. Specifically, the gas can flow along the cover portion (320A) during thermal runaway of the battery cell. In other words, the cover portion (320A) can form a path for the gas to be discharged. At this time, by comparing FIG. 5 and FIG. 6, it can be clearly seen that the shape in which the cover portion is lifted during thermal runaway of the battery cell is different from each other.

[0067] For example, in the case of FIG. 5, since the cover portion (320) is positioned at an angle, the gas ejected from the battery cell flows to the left (or right) direction, and consequently, there is a possibility that thermal runaway may occur in the battery cell positioned on the left. On the other hand, in the embodiment illustrated in FIG. 6, the gas ejected from the battery cell (100) can flow upward and be discharged immediately. Therefore, it is possible to prevent the gas from propagating to an adjacent battery cell through the space (S) between the battery cell (100) and the case top plate (220).

[0068] For reference, the position of the bend line (CL) can be set by considering the gap (S) between the upper surface of the battery cell and the case.

[0070] FIG. 7 is a perspective view illustrating a protective member according to another embodiment of the present invention.

[0071] Referring to FIG. 7, the cover portion (320B) of the protective member (300B) according to the present embodiment may be separated into a plurality of parts (320P1, 320P2, 320P3). Specifically, as shown in FIG. 7, the cover portion (320B) may be separated into a plurality of parts (320P1, 320P2, 320P3), for example, three parts (320P1, 320P2, 320P3). These three parts (320P1, 320P2, 320P3) may be arranged in the front-rear direction (Y-axis). Additionally, each part (320P1, 320P2, 320P3) may be configured to cover the upper portion of one battery cell (100). This can be implemented by making the length of each part (320P1, 320P2, 320P3) equal to or similar to the diameter of the battery cell (100). Additionally, a frame (322) can be attached to the edges on both sides (in the Y-axis direction) of each separated part (320P1, 320P2, 320P3).

[0072] According to the embodiment of the above configuration, when a battery cell undergoes thermal runaway, only the parts (320P1, 320P2, 320P3) positioned above the battery cell can be lifted. Therefore, the battery cell (100) can be protected more efficiently. For example, in the above embodiment, the cover portion (320) covers three battery cells (100) together. Therefore, when one battery cell undergoes thermal runaway, the entire cover portion (320) covering the three battery cells can be lifted. Consequently, the upper portion of the battery cell (100) that has not yet undergone thermal runaway is also opened, and thus the battery cell (100) may be exposed to gas or flames. However, in this embodiment, only the parts (320P1, 320P2, 320P3) covering the battery cell that has undergone thermal runaway are opened, and the other battery cells can be protected by the cover portion (320B).

[0074] FIG. 8 is a perspective view of a protective member according to another embodiment of the present invention, and FIG. 9 is a drawing for explaining the behavior of the protective member shown in FIG. 8.

[0075] Referring to FIGS. 8 and 9, the protective member (300C) according to the present embodiment may include a pair of cover portions (320C1, 320C2). Specifically, as shown in FIG. 8, a pair of cover portions (320C1, 320C2) are provided, and each cover portion (320C1, 320C2) may be connected to the top of the side wall portion (310). At this time, the pair of cover portions (320C1, 320C2) may be joined so as to face opposite directions, i.e., left and right respectively, and accordingly, the protective member (300C) may have an overall 'T'-shaped structure. Each cover portion (320C1, 320C2) may include an insulating pad (321) and a frame (322) that is joined to the edge of the insulating pad (321). At this time, the insulation pads (321) of a pair of cover parts (320C1, 320C2) can be formed integrally. That is, frames (322) can be attached to the left and right sides, respectively, based on the center line (R) of the insulation pad (321). Then, by connecting the central part of the insulation pad (321) to the side wall, a protective member (300C) having a pair of cover parts (320C1, 320C2) in a 'T' shape can be realized.

[0076] Alternatively, the insulation pads (321) of each cover part (320C1, 320C2) may be configured as separate pads. In other words, the protective member may be implemented in a form where the center line (R) of the insulation pad (321) is cut.

[0077] As illustrated in FIG. 9, when the protective member (300C) is placed between the battery cells (100), a pair of cover portions (320C1, 320C2) may be positioned to face in opposite directions. Accordingly, the cover portion (320C1) positioned on the left of the pair of cover portions can cover the upper portion of the battery cell (100) positioned on the left side of the side wall portion (310). And, the cover portion (320C2) positioned on the right can cover the upper portion of the battery cell (100) positioned on the right side of the side wall portion (310).

[0078] In particular, in the present embodiment, each cover portion (320C1, 320C2) can cover about half of the upper part of the battery cell. This can be achieved by making the length (length in the X-axis direction) of the cover portion (320C1, 320C2) approximately the radius of the battery cell (100). Accordingly, as shown in FIG. 9 (a), the upper part of the battery cell (100) (referring to the battery cell placed in the center) can be covered by the right cover portion (320C2) of the protective member placed on the left and the left cover portion (320C1) of the protective member placed on the right.

[0079] When thermal runaway occurs in the battery cell (100), two cover parts (320C1, 320C2) covering the battery cell (100) can be lifted as shown in FIG. 9 (b). At this time, the pair of cover parts (320C1, 320C2) can be arranged to block both sides of the space (S) between the battery cell (100) and the case (220). Thus, gases ejected from the battery cell (100) can be discharged directly upward without propagating to the left or right.

[0081] FIG. 10 is a drawing for explaining a protective member according to another embodiment of the present invention.

[0082] Referring to FIG. 10, the protective member (300D) according to the present embodiment may be provided with an expansion portion (330). The expansion portion (330) may include a material that expands upon heat. For example, polyurethane or foamed silicone may be included as the material of the expansion portion (330). The expansion portion (330) may be provided on the surface of the protective member (300D). For example, the expansion portion may be configured by applying foamed silicone to the surface of the protective member (300D).

[0083] The expansion portion (330) can expand when the battery cell undergoes thermal runaway. For example, if the expansion portion is provided on the side wall portion (310) of the protective member, the expansion portion (330) can expand to widen the gap with adjacent battery cells, thereby suppressing heat transfer between battery cells.

[0085] In particular, in the present embodiment, the expansion portion (330) may be configured to push the cover portion (320) upward. Specifically, the expansion portion (330) may be provided on the lower surface of the cover portion (320). At this time, as shown in FIG. 10, the expansion portion (330) may be provided at a location close to the connection point between the cover portion (320) and the side wall portion (310). When the battery cell (100) undergoes thermal runaway, the expansion portion (330) expands, and accordingly, the cover portion (320) may be lifted upward.

[0086] In this regard, the surface temperature of the battery cell may rise before venting occurs in the battery cell (100). Accordingly, before gas is ejected from the battery cell, the expansion part (330) may expand first and lift the cover part (320). If venting occurs while the cover part (320) is covered, the discharge of gas may not be smooth during the initial stage of venting. Additionally, the gas ejected initially may be blocked by the cover part (320) and propagate in all directions (horizontal direction). However, in the case of the present embodiment, since the cover part (320) is opened before venting of the battery cell, the gas can be smoothly guided and discharged from the initial stage of venting.

[0088] FIG. 11 is a drawing for explaining a protective member according to another embodiment of the present invention.

[0089] Referring to FIG. 11, the protective member (300E) according to the present embodiment may be provided with an expansion portion (330). Specifically, the protective member (300E) may have a pair of cover portions (320E1, 320E2). The expansion portion may be provided on the upper surface of the cover portions (320E1, 320E2). At this time, the expansion portion may be provided in the portion between the pair of cover portions (320E1, 320E2).

[0090] During thermal runaway of the battery cell (100), the expansion portion (330) can expand between a pair of cover portions (320E1, 320E2). Then, the cover portions (320E1, 320E2) are lifted by the ejected gas, and at this time, the expansion portion (330) can support the cover portions (320E1, 320E2). For convenience of explanation, the explanation is based on the protective member (300E) positioned on the left side in FIG. 11. During thermal runaway, the cover portion (320E2) positioned on the right side of the pair of cover portions (320E1, 320E2) is lifted. At this time, the upper surface of the battery cell (100) and the cover portion (320E2) must form an acute angle (an angle of 90 degrees or less) so that the gas can be discharged upward without propagating to the left or right. However, if the pressure of the ejected gas is strong or if the cover portion (320E2) is not sufficiently supported by the upper surface of the case, the cover portion (320E2) may be completely folded back. That is, in extreme cases, the right cover portion (320E2) may be rotated 180 degrees and placed on top of the left cover portion (320E1).

[0091] However, in the case of the present embodiment, the expansion portion (330) disposed between a pair of cover portions can support the right cover portion (320E2). Therefore, it is possible to prevent or suppress the right cover portion (320E2) from being excessively folded back.

[0093] FIG. 12 is a schematic perspective view of a protective member according to another embodiment of the present invention.

[0094] Referring to FIG. 12, a break line (X) may be provided in the protective member (300F) according to the present embodiment. The break line (X) is intended to allow a part of the protective member (300F) to be easily damaged by gas ejected from the battery cell, etc. Specifically, the break line (X) may be provided in the cover portion (320F). For example, as shown in FIG. 12, the break line (X) may be provided at the left end of the cover portion (320F). At this time, the break line (X) may be provided to correspond one to each battery cell (100). For example, if the cover portion (320F) covers three battery cells (100), three break lines (X) may also be provided. The break line (X) may be formed in a shape corresponding to the battery cell, for example, a semicircular shape. When the battery cell undergoes thermal runaway, the ejected gas, etc., the portion of the fracture line (X) is rapidly damaged, and accordingly, the portion surrounded by the fracture line can be separated from the cover portion (320F).

[0095] The effects of the present embodiment are explained with reference to FIG. 5. When a battery cell undergoes thermal runaway, the cover portion (320) can be lifted and positioned at an angle as shown in FIG. 5. At this time, as indicated by the curved arrow in FIG. 5 (b), the gas ejected upward is not discharged directly through the venting area, but its path is changed by the cover portion (320). In other words, the cover portion (320) blocks the venting gas, thereby changing the path of the gas.

[0096] On the other hand, in the present embodiment, the break line (X) portion of the cover portion (320F) is damaged and separated when the battery cell undergoes thermal runaway. Therefore, even if the cover portion (320F) is positioned at an angle as in FIG. 5, the upper part of the battery cell, i.e., the area where gas is ejected, is opened (i.e., separated by the break line). Thus, the ejected gas can be smoothly discharged upward.

[0098] Meanwhile, a fire-resistant layer may be formed on the surface of the protective member (300). For example, a fire-resistant material may be coated on the surface of the protective member. In this case, MICA or fire-resistant polymer materials (Fire-Resistant Polymers), such as Teflon (PTFE), may be used as the fire-resistant material. Alternatively, a fire-resistant tape may be attached to at least a part of the protective member.

[0099] The above fire-resistant layer can protect the insulation sheet (311, 321) by blocking the surface of the protective member, particularly the insulation sheet (311, 321), from being directly exposed to flame or heat.

[0101] Below, the structure of a cylindrical battery cell will be explained in more detail.

[0102] FIG. 13 is a cross-sectional perspective view illustrating a cylindrical battery cell.

[0103] Referring to FIG. 13, a cylindrical battery cell (100) may include an electrode assembly (10), a battery housing (20), an electrolyte, a current collector (30), and a housing cover (40). The battery cell (100) may further include an electrode terminal (50) and / or a sealing gasket (G1) and / or an insulating gasket and / or a second current collector (60) and / or an insulator (70).

[0104] The electrode assembly (10) may have a first blank portion (11) and a second blank portion (12). More specifically, the electrode assembly (10) has a structure in which the first electrode and the second electrode and the separator interposed between them are wound around a winding axis with a separator interposed between them, thereby defining a core and an outer surface. That is, the electrode assembly (10) may be a jelly-roll type electrode assembly (10). In this case, an additional separator may be provided on the outer surface of the electrode assembly (10) to insulate it from the battery housing (20). The electrode assembly (10) may have a winding structure well known in the art without limitation.

[0105] The battery housing (20) is a roughly cylindrical receptacle with an opening formed on one side and a hollow interior, and may include a conductive metal material. It is common for the side of the battery housing (20) and the bottom surface located opposite the opening to be formed integrally. That is, the battery housing (20) generally has one end open and the opposite end closed based on its height direction. For example, the bottom of the battery housing (20) may be open and the top closed. The battery housing (20) can accommodate an electrode assembly (10) inside through the opening formed at the bottom. The battery housing (20) can also accommodate an electrolyte through the opening. The battery housing (20) may have a beading portion (21) having a structure in which the outer circumference adjacent to the opening is indented inward. The battery housing (20) may have a crimping portion (22) formed at the top. The above clamping portion (22) may have a shape that is extended and indented from the beading portion (21).

[0106] The current collector (30) is housed inside the battery housing (20) and can be positioned on one side of the electrode assembly (10). The current collector (30) can be electrically connected by being coupled to the electrode assembly (10) and also electrically connected by being coupled to the battery housing (20). Accordingly, the current collector (30) can electrically connect the electrode assembly (10) and the battery housing (20).

[0107] The housing cover (40) can cover an opening formed on one side of the battery housing (20). The housing cover (40) can be fixed by a clamping part (22). In this case, a sealing gasket (G1) may be interposed between the battery housing (20) and the housing cover (40) and between the current collector (30) and the housing cover (40) to improve fixing force and sealing performance of the battery housing (20).

[0109] FIG. 14 is a drawing for explaining a battery pack according to an embodiment of the present invention, and FIG. 15 is a drawing for explaining a vehicle according to an embodiment of the present invention.

[0111] Referring to FIG. 14, the battery pack (1) may include at least one battery module (1000) of the preceding embodiment and a pack case that accommodates the at least one battery module (1000).

[0112] The above battery pack (1) may further include various battery pack components known at the time of filing of the present invention, such as a BMS, busbar, relay, current sensor, etc.

[0113] Meanwhile, components such as a BMS, busbar, relay, and current sensor may be included as components of the battery module according to the present invention. In this case, components such as a BMS, busbar, relay, and current sensor may be provided inside the case (200). At this time, the battery module may be referred to as a battery pack, and the case may be referred to as a pack case. Furthermore, in this case, the battery module according to the present invention may be a cell-to-pack type battery pack in which a battery cell (100) is directly mounted in the pack case.

[0115] Referring to FIG. 15, the battery pack (1) can be provided in a vehicle (V) as a fuel source for the vehicle. For example, the battery pack (1) can be provided in an electric vehicle, a hybrid vehicle, and other vehicles (V) in other ways that can utilize the battery pack (1) as a fuel source.

[0116] The battery pack (1) and the vehicle (V) according to the present embodiment are equipped with the battery module (1000) of the preceding embodiment, thereby enabling the realization of a battery pack (1) and a vehicle (V) that possess all the advantages of the battery module (1000) of the preceding embodiment.

[0117] In addition, it goes without saying that the battery pack (1) may also be equipped in other devices, mechanisms, and facilities, such as an energy storage system using a secondary battery, in addition to the vehicle (V).

[0119] Although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the invention as claimed in the claims, and such modifications should not be understood individually from the technical spirit or perspective of the present invention. Explanation of the symbols

[0120] V: Car 1: Battery pack 1000: Battery module 100: Battery cell 10: Electrode assembly 20: Battery housing 30: Whole house 50: Electrode terminal 60: Entire 2nd Album 70: Insulator 200: Case 210: Main body 220: Top plate 300: Protection absence 310: Sidewall 320: Cover section 330: Expansion part 311,321: Insulation pad 312,322: Frame G1: Sealing gasket VL: Venting line X: Break line

Claims

Claim 1 A battery module characterized by comprising: a plurality of battery cells; a case accommodating the plurality of battery cells in an internal space; and a protective member having a side wall portion disposed between the battery cells and a cover portion disposed to cover the upper portion of the battery cells and connected to the side wall portion. Claim 2 A battery module according to claim 1, wherein each of the side wall portion and the cover portion comprises a plate-shaped insulation pad and a frame coupled to the edge of the insulation pad to support the insulation pad. Claim 3 A battery module according to claim 1, wherein the cover portion has a bending line and is capable of being bent along the bending line. Claim 4 A battery module according to claim 1, wherein the cover portion is separated into a plurality of parts. Claim 5 A battery module according to claim 1, wherein the protective member comprises a pair of cover portions, wherein one of the pair of cover portions is positioned to cover the upper portion of battery cells arranged on one side of the side wall portion, and the other of the pair of cover portions is positioned to cover the upper portion of battery cells arranged on the other side of the side wall portion. Claim 6 A battery module according to claim 1, characterized in that the protective member is provided with an expansion portion that expands by heat. Claim 7 A battery module according to claim 6, wherein the expansion portion is configured to push the cover portion upward when expanded. Claim 8 A battery module according to claim 1, characterized in that a fire-resistant layer having fire resistance is provided on the surface of the protective member. Claim 9 A battery pack characterized by including at least one battery module according to any one of claims 1 to 8. Claim 10 An automobile characterized by including at least one battery module according to any one of claims 1 to 8.

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