Battery cell assembly and battery pack comprising same

Abstract

The battery cell assembly comprises a battery cell block which comprises a plurality of battery cells; and a side frame disposed on one side surface of the battery cell block, in which the side frame includes a side wall portion and a flange portion disposed on the side wall portion on a side opposite to the battery cell block and configured to be fastened to an external support structure, and in which the side frame includes a side wall portion and a flange portion disposed on the side wall portion on a side opposite to the battery cell block and configured to be fastened to the external support structure. The side wall portion includes a hollow space formed through an interior of the side wall portion.

Description

Technical Field

[0001] The present disclosure relates to a battery cell assembly and a battery pack including the battery cell assembly. Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices (e.g., handheld devices, laptop computers, and cordless vacuum cleaners). In recent years, as the manufacturing cost per unit capacity of secondary batteries has decreased significantly due to increased energy density and economies of scale, and the driving range of battery electric vehicles (BEVs) has increased to a level comparable to that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to mobilities.

[0003] Since secondary batteries are used in mobilities, the demand for the safety of secondary batteries is increasing. When an accident such as a fire occurs in a secondary battery used in a mobility, the life of the driver is endangered, so research on technologies to improve the safety of secondary batteries is crucial.

[0004] The background description provided herein is for the purpose of generally presenting the background of the present disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not considered prior art or suggestions of prior art by virtue of being included in this section. Summary of the Invention

[0005] Technical Problem

[0006] The present disclosure aims to provide a battery cell assembly and a battery pack with improved safety.

[0007] This object and other objects and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Moreover, it will be readily understood that the objects and advantages of the present disclosure can be achieved by the means shown in the appended claims and their combinations.

[0008] Technical Solution

[0009] The present disclosure relates to a battery cell assembly, the battery cell assembly including: a cell block including a plurality of battery cells; and a side frame disposed on one side surface of the cell block, wherein the side frame includes a side wall portion and a flange portion, the flange portion being disposed on the side wall portion on a side opposite to the cell block and configured to be fastened to an external support structure, and wherein the side wall portion includes a hollow space formed through the interior of the side wall portion.

[0010] In an exemplary embodiment, the hollow space may include an upper buffer space and a lower buffer space. Wherein, the side wall portion may include an inner side wall, a first outer side wall, and a second outer side wall. The inner side wall faces one side surface of the battery cell block. The first outer side wall is spaced apart from an upper portion of the inner side wall, and the upper buffer space is located between the upper portion of the inner side wall and the first outer side wall. The second outer side wall is spaced apart from a lower portion of the inner side wall, and the lower buffer space is located between the lower portion of the inner side wall and the second outer side wall. Wherein, the flange portion may be connected to the first outer side wall and the second outer side wall. Wherein, each of the first outer side wall and the second outer side wall may be spaced apart from the inner side wall in a first direction, and wherein, the first outer side wall may be spaced apart from the second outer side wall.

[0011] In an exemplary embodiment, the plurality of battery cells may be stacked in the first direction.

[0012] In an exemplary embodiment, the side wall portion may further include: an upper wall extending between an upper end portion of the inner side wall and an upper end portion of the first outer side wall; and a lower wall extending between a lower end portion of the inner side wall and a lower end portion of the second outer side wall. Wherein, the upper buffer space may be defined by an upper portion of the inner side wall, the upper wall, and the first outer side wall, and wherein, the lower buffer space may be defined by a lower portion of the inner side wall, the lower wall, and the second outer side wall.

[0013] In an exemplary embodiment, the upper buffer space may communicate with the lower buffer space through an intermediate buffer space near a middle portion of the inner side wall. Wherein, the flange portion may include an internal space through which a fastening member passes, and wherein, the internal space of the flange portion may communicate with the intermediate buffer space.

[0014] In an exemplary embodiment, the flange portion may include: an upper fastening plate through which the fastening member passes; a lower fastening plate through which the fastening member passes, and the lower fastening plate is spaced apart from the upper fastening plate and the internal space is located between the upper fastening plate and the lower fastening plate; and a connecting plate connecting the upper fastening plate to the lower fastening plate.

[0015] In an exemplary embodiment, the flange portion may further include: a reinforcing rib extending from the upper fastening plate to the lower fastening plate, and the reinforcing rib is closer to the inner side wall of the side wall portion than the connecting plate.

[0016] In an exemplary embodiment, the battery cell assembly may further include: a bottom cover plate, which is located below the cell block and coupled to a lower end portion of the side wall portion.

[0017] In an exemplary embodiment, the battery cell assembly may further include: a top cover plate, which is located on the cell block and coupled to an upper end portion of the side wall portion.

[0018] In an exemplary embodiment, the top cover plate may include a cooling channel.

[0019] The present disclosure also relates to a battery pack, which includes: a battery pack housing, the battery pack housing including a support structure; and a battery cell assembly, the battery cell assembly being received in the battery pack housing, wherein the battery cell assembly includes a cell block and a side frame, the cell block including a plurality of battery cells, the side frame being disposed on one side surface of the cell block, wherein the side frame includes a side wall portion and a flange portion, the flange portion being disposed on the side wall portion on a side opposite to the cell block and fastened to the support structure, and wherein the side wall portion includes a hollow space formed through an interior of the side wall portion.

[0020] In an exemplary embodiment, the hollow space may include an upper buffer space, an intermediate buffer space, and a lower buffer space, wherein the side wall portion may include an inner side wall, a first outer side wall, and a second outer side wall, the inner side wall facing the one side surface of the cell block, the first outer side wall being spaced apart from an upper portion of the inner side wall and the upper buffer space being located between the upper portion of the inner side wall and the first outer side wall, the second outer side wall being spaced apart from a lower portion of the inner side wall and the lower buffer space being located between the lower portion of the inner side wall and the second outer side wall, wherein the flange portion may be connected to the first outer side wall and the second outer side wall, wherein the upper buffer space may communicate with the lower buffer space through the intermediate buffer space, wherein the flange portion may include: an upper fastening plate, a fastening member passing through the upper fastening plate; a lower fastening plate, the fastening member passing through the lower fastening plate, and the lower fastening plate being spaced apart from the upper fastening plate, and an internal space being located between the upper fastening plate and the lower fastening plate; and a connecting plate, the connecting plate connecting the upper fastening plate to the lower fastening plate, and wherein the internal space may communicate with the intermediate buffer space.

[0021] In an exemplary embodiment, the battery cell assembly may further include: a bottom cover plate, which is located below the cell block; and a top cover plate, which is located above the cell block and includes a cooling channel.

[0022] In an exemplary embodiment, the battery cell assembly and the bottom wall of the battery pack housing may be spaced apart from each other to form a first space.

[0023] In an exemplary embodiment, the side wall portion may further include: an upper wall that extends between an upper end portion of the inner side wall and an upper end portion of the first outer side wall and is coupled to the top cover plate; and a lower wall that extends between a lower end portion of the inner side wall and a lower end portion of the second outer side wall and is coupled to the bottom cover plate.

[0024] In an exemplary embodiment, each of the plurality of battery cells may be a pouch-type battery cell.

[0025] In an exemplary embodiment, a sealed portion of the pouch of the pouch-type battery cell in the cell block may face the first space.

[0026] In an exemplary embodiment, each of the plurality of battery cells may be a cylindrical battery cell or a prismatic battery cell including an exhaust portion.

[0027] In an exemplary embodiment, the exhaust portion of the cylindrical battery cell or the prismatic battery cell may face the first space.

[0028] The present disclosure also relates to an electric mobile device including a battery pack, the battery pack including: a battery pack housing including a support structure; and a battery cell assembly accommodated in the battery pack housing, wherein the battery cell assembly includes a cell block and a side frame, the cell block includes a plurality of battery cells, the side frame is disposed on one side surface of the cell block, wherein the side frame includes a side wall portion and a flange portion, the flange portion is disposed on the side wall portion on a side opposite to the cell block and is fastened to the support structure, wherein the side wall portion includes a hollow space formed through an interior of the side wall portion.

[0029] According to an exemplary embodiment of the present disclosure, due to the expansion of the battery cell, the force acting between the cell block and the fastening portion that fastens the battery cell assembly to the battery pack housing may increase, but this force can be weakened and distributed by a buffer space provided in the side wall portion of the side frame. Since this force is weakened and distributed by the buffer space provided in the side wall portion of the side frame, the pressure applied to the fastening portion between the battery cell assembly and the battery pack housing can be reduced, and damage to the fastening portion between the battery cell assembly and the battery pack housing can be reduced. In addition, since this force is weakened and distributed by the buffer space provided in the side wall portion of the side frame, the surface pressure applied to the cell block or the battery cell can be made more uniform. Therefore, the structural safety of the battery cell assembly can be improved, and the safety and reliability of the battery cell assembly and the battery pack including the battery cell assembly can be improved.

[0030] The effects obtained in the exemplary embodiments of the present disclosure are not limited to the above effects, and other effects not mentioned above can be clearly obtained and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, those skilled in the art can also obtain the unexpected effects of implementing the exemplary embodiments of the present disclosure according to the exemplary embodiments of the present disclosure.

[0031] Advantageous Effects

[0032] According to an embodiment, the force can be weakened and distributed by a buffer space provided in the side wall portion. Since the force is weakened and distributed by the buffer space provided in the side wall portion, the pressure applied to the fastening portion between the side frame and the support structure can be reduced, and damage to the fastening member (such as a bolt), the side frame, and / or the support structure can be reduced. In addition, since the force is weakened and distributed by the buffer space provided in the side wall portion, the surface pressure applied to the cell block or the battery cell can become more uniform. Therefore, the structural safety of the battery cell assembly can be improved, and the safety and reliability of the battery cell assembly and the battery pack including the battery cell assembly can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a cross-sectional view showing a battery pack according to an exemplary embodiment of the present disclosure.

[0034] Figure 2 is a perspective view showing a battery cell assembly according to an exemplary embodiment of the present disclosure.

[0035] Figure 3 is a cross-sectional view showing a side frame of a battery cell assembly according to an exemplary embodiment of the present disclosure.

[0036] Figure 4 is a cross-sectional view showing a side frame according to a comparative example.

[0037] Figure 5 is a cross-sectional view showing a side frame according to an exemplary embodiment of the present disclosure.

[0038] Figure 6 is a schematic view showing an electric vehicle equipped with a battery pack according to an exemplary embodiment of the present disclosure. Detailed Description of the Embodiments

[0039] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, terms and words used in the present disclosure and the claims should not be construed as limited to general or dictionary terms, but should be interpreted based on the concept that the inventor has appropriately defined the terms in order to best explain the principles of the present invention, using the meanings and concepts according to the technical concept of the present disclosure.

[0040] Therefore, since the embodiments described herein and the configurations shown in the drawings are merely an example of the present disclosure and do not represent all the technical concepts of the present disclosure, it should be understood that the present disclosure encompasses various equivalents, modifications, and substitutions at the time of filing of this application.

[0041] In addition, in the following description of the present disclosure, when it is determined that a detailed description of a known configuration or function incorporated herein may make the gist of the present disclosure rather unclear, such a description will be omitted.

[0042] Since the embodiments of the present disclosure are provided to more comprehensively illustrate the present disclosure to those of ordinary skill in the art, for clarity, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically shown. Therefore, the dimensions or ratios of each component do not fully reflect the actual dimensions or ratios.

[0043] Figure 1 is a cross-sectional view showing a battery pack 500 according to an exemplary embodiment of the present disclosure. Figure 2 is a perspective view showing a battery cell assembly 100 according to an exemplary embodiment of the present disclosure. Figure 3 is a cross-sectional view showing a side frame 120 of a battery cell assembly 100 according to an exemplary embodiment of the present disclosure.

[0044] Referring to Figures 1 to 3 , the battery pack 500 may include a battery pack housing 501 and a battery cell assembly 100 installed in the battery pack housing 501. The battery pack 500 may include one or more battery cell assemblies 100 installed in the battery pack housing 501. In an exemplary embodiment, the battery pack 500 may include two or more battery cell assemblies 100 arranged in a first direction (X direction).

[0045] The battery pack housing 501 may include a lower housing 510 and a battery pack cover 520. The lower housing 510 has a receiving space for accommodating the battery cell assembly 100, and the battery pack cover 520 is coupled to the lower housing 510 to cover the battery cell assembly 100 accommodated in the lower housing 510. The receiving space of the lower housing 510 may be defined by a bottom wall 511 facing the lower surface of each cell block 110 of the battery cell assembly 100 and a side wall 513 located at the periphery of the bottom wall 511.

[0046] The battery cell assembly 100 may include a cell block 110, a side frame 120, a top cover plate 131, and a bottom cover plate 135.

[0047] The cell block 110 may include a plurality of battery cells 111. Each battery cell 111 is a basic unit of a lithium-ion battery (i.e., a secondary battery). Each battery cell 111 may include an electrode assembly, an electrolyte, and a cell housing. The electrode assembly embedded in the cell housing may include a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. Depending on the assembly type, the electrode assembly may be either a wound-type electrode assembly or a stacked-type electrode assembly. The wound-type electrode assembly may include a wound structure of a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. The stacked-type electrode assembly may include a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators respectively between the positive electrodes and the negative electrodes, all of which are sequentially stacked on one another. The positive electrode may include a positive electrode current collector and a positive electrode active material. The negative electrode may include a negative electrode current collector and a negative electrode active material.

[0048] The plurality of battery cells 111 may be connected in series and / or in parallel. As an example, the plurality of battery cells 111 may be connected in series with each other. As another example, the plurality of battery cells 111 may be connected in parallel with each other. As another example, when a group of two or more battery cells 111 connected in parallel with each other is defined as one battery bank, one group composed of two or more battery cells 111 connected in parallel with each other and another group composed of two or more battery cells 111 connected in parallel with each other may be connected in series.

[0049] Each battery cell 111 may correspond to a pouch-type battery cell, a cylindrical battery cell, or a prismatic battery cell. The electrode assembly may be included in various cell casings (e.g., a pouch, a cylindrical can, or a prismatic can). The electrode assembly of the pouch-type battery cell may be included in a pouch casing including an aluminum laminate. The electrode assembly of the cylindrical battery cell may be included in a cylindrical metal can. The electrode assembly of the prismatic battery cell may be included in a prismatic metal can. Each battery cell 111 may include an exhaust portion facing the first space. For example, the exhaust portion of each battery cell 111 may be disposed in the cell casing of the battery cell 111. When the pressure in the cell casing of each battery cell 111 exceeds a certain level, the gas in the cell casing of each battery cell 111 may be discharged into the first space through the exhaust portion of each battery cell 111. The first space may be provided between the bottom wall 511 of the lower housing 510 and the battery cell assembly 100.

[0050] In an exemplary embodiment, each battery cell 111 may correspond to a pouch-type battery cell, and a plurality of battery cells 111 may be stacked in a first direction (X direction) in one battery cell assembly 100 (e.g., Figure 1 ). In an exemplary embodiment, in each battery cell assembly, each of the plurality of battery cells 111 may correspond to a pouch-type battery cell having a length (thickness) in the first direction (X direction) smaller than a length in the second direction (Y direction), and the plurality of battery cells 111 may be stacked in the first direction (X direction). In an exemplary embodiment, each battery cell 111 may be a pouch-type battery cell, and the sealed portion of the pouch in the pouch-type battery cell may face the first space so that gas and / or flame can be easily discharged from the battery cell. When the pressure in the pouch exceeds a certain level, the sealed portion of the pouch is partially ruptured, and the gas in the pouch may be discharged into the first space through the ruptured portion of the sealed portion.

[0051] When viewed in a plan view, the cell block 110 may have a rectangular shape in which the length in the first direction (X direction) is smaller than the length in the second direction (Y direction). In this case, the cell block 110 may have a first side surface and a second side surface opposite to each other in the first direction (X direction), a front surface and a rear surface opposite to each other in the second direction (Y direction), and a top surface and a bottom surface opposite to each other in the third direction (Z direction).

[0052] The bus bar frame for installing the bus bar can be provided on each of the front surface and the rear surface of the battery cell block 110. A plurality of bus bars can be installed on the bus bar frame at the front surface of the battery cell block 110, and can also be installed on the bus bar frame at the rear surface of the battery cell block 110. The battery cell assembly 100 can include an end plate 141 for covering the bus bar frame connected to the front surface or the rear surface of the cell block 110.

[0053] The bus bar can be connected to the electrode lead of the battery cell 111. For example, the bus bar can be connected to the electrode lead of the battery cell 111 by a welding method. For example, each bus bar can be an intermediate bus bar for electrically connecting different battery cells 111 belonging to the cell block 110 by connecting to the electrode leads connected to different battery cells 111. For example, each bus bar can be a terminal bus bar for electrically connecting the battery cell assembly 100 to other external electrical devices.

[0054] In an exemplary embodiment, the battery cell assembly 100 can include a single cell block 110. In another exemplary embodiment, the battery cell assembly 100 can include a cell block array composed of a plurality of cell blocks 110 arranged in the second direction (Y direction). For example, the battery cell assembly 100 can include two cell blocks 110 arranged in the second direction (Y direction). As an example, the battery cell assembly 100 can include a first cell block and a second cell block arranged in the second direction (Y direction) and electrically connected to each other.

[0055] The side frames 120 can be provided at each of the two sides of the cell block 110. The battery cell assembly 100 can be fastened to the battery pack housing 501 by a side mounting method, in which the battery cell assembly 100 is fastened to the support structure 515 of the battery pack housing 501 through the side frames 120.

[0056] The side frame 120 may include a side wall portion 121 connected to the side surface of the cell block 110 and a flange portion 125 fastened to the support structure 515 of the battery pack housing 501 by fastening members (such as bolts BT) and supported by the support structure 515. Each of the side wall portion 121 and the flange portion 125 may be a part of the side frame 120, and the side wall portion 121 and the flange portion 125 may be formed integrally. For example, the side frame 120 may be formed by an extrusion process, and the side wall portion 121 and the flange portion 125 may be made of the same material. The side wall portion 121 may be closer to the cell block 110 than the flange portion 125 and may extend along the side surface of the cell block 110 in the second direction (Y direction) and the third direction (Z direction). A plurality of flange portions 125 may be connected to the side wall portion 121, and the plurality of flange portions 125 may be arranged to be spaced apart from each other in the second direction (Y direction).

[0057] The side wall portion 121 may include a hollow space formed through the interior of the side wall portion 121. The hollow space may include an upper buffer space 241, an intermediate buffer space 245, and a lower buffer space 243. The side wall portion 121 may include an inner side wall 210 facing the side surface of the cell block 110, a first outer side wall 221 spaced apart from the upper portion of the inner side wall 210 (where the upper buffer space 241 is located between the upper portion of the inner side wall 210 and the first outer side wall 221), a second outer side wall 223 spaced apart from the lower portion of the inner side wall 210 (where the lower buffer space 243 is located between the lower portion of the inner side wall 210 and the second outer side wall 223), an upper wall 231 extending between the upper end portion (or upper edge) of the inner side wall 210 and the upper end portion (or upper edge) of the first outer side wall 221, and a lower wall 233 extending between the lower end portion (or lower edge) of the inner side wall 210 and the lower end portion (or lower edge) of the second outer side wall 223. The first outer side wall 221 and the second outer side wall 223 may be spaced apart from each other in the third direction (Z direction).

[0058] The inner side wall 210 may have a flat plate shape. For example, the inner side wall 210 may have a flat plate shape perpendicular to the first direction (X direction). The inner side wall 210 may have an upper portion facing the first outer side wall 221 in the first direction (X direction), a lower portion facing the second outer side wall 223 in the first direction (X direction), and an intermediate portion extending in the third direction (Z direction) between the upper and lower portions of the inner side wall 210. The thickness of the inner side wall 210 (i.e., the thickness of the inner side wall 210 in the first direction (X direction)) may be substantially uniform. The thickness of the inner side wall 210 may be in the range of several millimeters, for example, in the range between 1 mm and 4 mm.

[0059] The first outer wall 221 may have a flat plate shape. For example, the first outer wall 221 may have a flat plate shape perpendicular to the first direction (X direction). The first outer wall 221 may be spaced apart from the upper portion of the inner wall 210 in the first direction (X direction). The thickness of the first outer wall 221 (i.e., the thickness of the first outer wall 221 in the first direction (X direction)) may be substantially uniform. The thickness of the first outer wall 221 may be in the range of several millimeters, for example, in the range between 1 mm and 4 mm. The distance between the first outer wall 221 and the inner wall 210 in the first direction (X direction) may be substantially uniform. For example, the distance between the first outer wall 221 and the inner wall 210 in the first direction (X direction) may be in the range of several millimeters.

[0060] Since the first outer wall 221 is spaced apart from the inner wall 210 in the first direction (X direction), the upper buffer space 241 may be provided between the first outer wall 221 and the inner wall 210. The upper buffer space 241 may be defined by the upper portion of the inner wall 210, the first outer wall 221, and the upper wall 231. The width of the upper buffer space 241 in the first direction (X direction) (i.e., the distance between the inner wall 210 and the first outer wall 221 in the first direction (X direction)) may be uniform. The width of the upper buffer space 241 in the first direction (X direction) may be in the range of several millimeters, for example, in the range between 2 mm and 6 mm or in the range between 3 mm and 5 mm.

[0061] The second outer wall 223 may have a flat plate shape. For example, the second outer wall 223 may have a flat plate shape perpendicular to the first direction (X direction). The second outer wall 223 may be spaced apart from the lower portion of the inner wall 210 in the first direction (X direction). The thickness of the second outer wall 223 (i.e., the thickness of the second outer wall 223 in the first direction (X direction)) may be substantially uniform. The thickness of the second outer wall 223 may be in the range of several millimeters, for example, in the range between 1 mm and 4 mm. The thickness of the first outer wall 221 and the thickness of the second outer wall 223 may be substantially the same. The distance between the second outer wall 223 and the inner wall 210 in the first direction (X direction) may be substantially uniform. For example, the distance between the second outer wall 223 and the inner wall 210 in the first direction (X direction) may be in the range of several millimeters. The distance between the second outer wall 223 and the inner wall 210 in the first direction (X direction) may be the same as or similar to the distance between the first outer wall 221 and the inner wall 210 in the first direction (X direction).

[0062] Since the second outer wall 223 is spaced apart from the inner wall 210 in the first direction (X direction), the lower buffer space 243 can be provided between the second outer wall 223 and the inner wall 210. The lower buffer space 243 can be defined by the lower portion of the inner wall 210, the second outer wall 223, and the lower wall 233. The width of the lower buffer space 243 in the first direction (X direction) (i.e., the distance between the inner wall 210 and the second outer wall 223 in the first direction (X direction)) can be uniform. The width of the lower buffer space 243 in the first direction (X direction) can be in the range of several millimeters, for example, in the range between 2 mm and 6 mm or in the range between 3 mm and 5 mm. The width of the lower buffer space 243 in the first direction (X direction) can be the same as the width of the upper buffer space 241 in the first direction (X direction).

[0063] The upper buffer space 241 and the lower buffer space 243 can communicate with each other. More specifically, the upper buffer space 241 can communicate with the lower buffer space 243 through an intermediate buffer space 245 adjacent to the middle portion of the inner wall 210. The intermediate buffer space 245 can be provided between the lower end of the first outer wall 221 and the upper end of the second outer wall 223 in the third direction (Z direction). The upper buffer space 241, the intermediate buffer space 245, and the lower buffer space 243 can communicate with each other to form an integrated single buffer space, i.e., a hollow space.

[0064] The flange portion 125 can have an internal space 259 communicating with the intermediate buffer space 245. The flange portion 125 can include an upper fastening plate 251, a lower fastening plate 253, and a connecting plate 255.

[0065] The upper fastening plate 251 can be connected to the lower end of the first outer wall 221 and can extend in the first direction (X direction) from the lower end of the first outer wall 221. The upper fastening plate 251 can include fastening holes for bolts BT to pass through. The upper fastening plate 251 can have a flat plate shape perpendicular to the third direction (Z direction). The thickness of the upper fastening plate 251 (i.e., the thickness of the upper fastening plate 251 in the third direction (Z direction)) can be in the range of several millimeters, for example, in the range between 2 mm and 5 mm.

[0066] The lower fastening plate 253 may be connected to the upper end of the second outer sidewall 223 and may extend in a first direction (X direction) from the upper end of the second outer sidewall 223. The upper fastening plate 251 and the lower fastening plate 253 may be spaced apart from each other in a third direction (Z direction), and an internal space 259 is located between the upper fastening plate 251 and the lower fastening plate 253. The lower fastening plate 253 may include fastening holes through which bolts BT pass. The fastening holes of the lower fastening plate 253 and the fastening holes of the upper fastening plate 251 may be aligned with each other in the third direction (Z direction). The thickness of the lower fastening plate 253 (i.e., the thickness of the lower fastening plate 253 in the third direction (Z direction)) may have a range of several millimeters, for example, in the range between 2 mm and 5 mm.

[0067] The connecting plate 255 may extend in a third direction (Z direction) between the upper fastening plate 251 and the lower fastening plate 253. The connecting plate 255 may extend from the outer edge of the upper fastening plate 251 to the outer edge of the lower fastening plate 253 in the third direction (Z direction). The internal space 259 of the flange portion 125 may be defined by the upper fastening plate 251, the lower fastening plate 253, and the connecting plate 255. Bolts BT pass through the upper fastening plate 251 and the lower fastening plate 253 and may pass through the internal space 259 of the flange portion 125.

[0068] The flange portion 125 may further include reinforcing ribs 257 for strengthening the rigidity of the side frame 120. The reinforcing ribs 257 extend across the internal space 259 of the flange portion 125 in the third direction (Z direction) and may extend from the lower surface of the upper fastening plate 251 to the upper surface of the lower fastening plate 253 in the third direction (Z direction). The reinforcing ribs 257 may be located between the inner sidewall 210 of the sidewall portion 121 and the connecting plate 255, or closer to the inner sidewall 210 of the sidewall portion 121 than the connecting plate 255.

[0069] The top cover plate 131 may cover the upper surface of the battery cell block 110. The top cover plate 131 may be coupled to the upper end portions of each side frame provided on both sides of the battery cell block 110. For example, one side portion of the top cover plate 131 may be coupled to the upper end portion of the side frame by welding. For example, one side portion of the top cover plate 131 may be coupled to the upper wall 231 of the side frame 120.

[0070] The top cover plate 131 may be attached to the upper surface of the battery cell block 110 and may be thermally coupled to the battery cell block 110. The top cover plate 131 may be attached to the upper surface of the battery cell block 110 through a thermally conductive adhesive layer interposed between the top cover plate 131 and the upper surface of the battery cell block 110. For example, the thermally conductive adhesive layer may include a thermal interface material (TIM).

[0071] The top cover plate 131 may include a cooling channel 1311 configured to allow a cooling fluid to flow therethrough and may be configured to cool the cell block 110. The top cover plate 131 may be referred to as a cooling plate. The top cover plate 131 may be configured to cool the cell block 110 by thermally coupling to the cell block 110 via a thermally conductive adhesive layer. The cooling fluid provided from the outside of the battery cell assembly 100 may flow into the cooling channel 1311 through the inlet of the cooling channel 1311, flow along the cooling channel 1311, and then flow out to the outside through the outlet of the cooling channel 1311. The cooling of the battery cell assembly 100 may be performed while the cooling fluid flows along the cooling channel 1311. For example, the top cover plate 131 may be manufactured by combining two plates, and the cooling channel 1311 may include a space defined between the two plates.

[0072] The bottom cover plate 135 may extend along the lower surface of the cell block 110 and cover the lower surface of the cell block 110. The bottom cover plate 135 may be coupled to the lower end portions of each side frame provided on both sides of the cell block 110. For example, one side portion of the bottom cover plate 135 may be coupled to the lower end portion of the side frame by welding. For example, one side portion of the bottom cover plate 135 may be coupled to the lower wall 233 of the side frame 120. The bottom cover plate 135, the top cover plate 131, and the side frame 120 may together form a housing surrounding the cell block 110. The bottom cover plate 135 may include an exhaust channel to discharge the high-temperature gas generated in the cell block 110 to the space below the cell block 110.

[0073] When the battery pack 500 is installed in a vehicle, the passenger compartment (the area where the passengers are in the vehicle) may be located above the battery pack cover 520, and the ground on which the vehicle travels may be located below the lower housing 510.

[0074] The battery cell assembly 100 may be supported by a support structure 515 provided on the bottom wall 511 of the lower housing 510 by a side mounting method, and a free volume FV (a first space) may be provided between the bottom wall 511 of the lower housing 510 and the battery cell assembly 100. The gas and flame generated in the case of thermal runaway may move through the free volume FV. That is, the free volume FV (the first space) becomes an exhaust channel through which the high-temperature gas and flame may move.

[0075] In addition, even when a strong impact is generated due to a foreign object rebounding onto the lower part of the vehicle during driving on a hard surface such as an unpaved road, the free volume FV (the first space) can absorb the impact. Therefore, damage to the plurality of battery cell assemblies 100 due to the impact can be prevented. The free volume FV (the first space) has an empty space between each battery cell assembly of the plurality of battery cell assemblies 100 and the lower housing 510, and when the lower housing 510 deforms toward the battery cell assembly 100 due to an impact applied to the lower part of the vehicle, the free volume FV (the first space) can serve as a space allowing a certain degree of freedom of deformation of the lower housing 510.

[0076] The height of the free volume FV (the first space) and the distance between the bottom wall of the lower housing 510 and the battery cell assembly 100 can be set to sufficiently absorb an external impact. The height of the free volume FV can be determined in consideration of the size and rigidity of the vehicle frame, the size and rigidity of the lower housing 510, the size of the battery pack 500, the amount and discharge rate of the gas generated during thermal runaway, and the like. For example, when the thickness or rigidity of the vehicle frame or the bottom wall of the lower housing 510 is relatively large, at least one of the size and height of the free volume FV (the first space) can be relatively reduced. In addition, when the thickness or rigidity of the vehicle frame or the bottom wall of the lower housing 510 is relatively small, the bottom wall of the lower housing 510 is more likely to deform, so at least one of the size and height of the free volume FV (the first space) can be relatively increased to protect the battery cell assembly 100. In addition, when the size of the battery pack 500 is relatively large according to the specifications of the battery pack 500, a relatively large free volume FV (the first space) can be ensured. When the size of the battery pack 500 is relatively small, the height of the free volume FV (the first space) that can be ensured can be relatively small, and it may be necessary to relatively increase the thickness and rigidity of the bottom wall of the lower housing 510. In addition, when the height of the free volume FV (the first space) is too small, the gas discharge channel is reduced, so that the internal pressure of the battery pack 500 may increase sharply during thermal runaway. Therefore, the size and height of the free volume FV (the first space) can be determined in consideration of the amount and discharge rate of the generated gas.

[0077] The maximum height of the free volume FV (the first space) can be determined according to the degree of damage to the battery cells 111 included in the battery cell assembly 100. For example, when the allowable damage limit of the battery cells 111 is 1 mm, the free volume FV can be determined such that when the lower housing 510 deforms and presses the lower surface of the battery cells 111, the battery cells 111 do not deform by more than 1 mm. In this case, the amount of deformation of the lower housing 510 can vary depending on the thickness or rigidity of the lower housing 510. Therefore, the size or height of the free volume FV (the first space) can be determined in consideration of the allowable damage limit of the battery cells 111 and the thickness and rigidity of the lower housing 510.

[0078] In an exemplary embodiment, the upper surface of the battery cell assembly 100 may be in close contact with the lower surface of the battery pack cover 520. When there is a space between the battery cell assembly 100 and the battery pack cover 520, during thermal runaway, high-temperature gases may be introduced into the space between the battery cell assembly 100 and the battery pack cover 520, and thus heat and flames may spread to another adjacent battery cell assembly 100. Additionally, there is a concern that heat and flames may also be transferred to the battery pack cover 520 and affect the passenger compartment above the battery pack cover 520. Therefore, by bringing the upper surface of the battery cell assembly 100 into close contact with the lower surface of the battery pack cover 520, gases or flames generated inside the battery pack 500 can be directed to the free volume FV (the first space).

[0079] Figure 4 is a cross-sectional view showing the side frame 190 according to the comparative example.

[0080] Refer to Figure 4 , the side frame 190 according to the comparative example may include a side wall 191 connected to one side of the cell block and a flange portion 195 connected to the side wall 191. The side frame 190 may be bolted to the support structure 515 ( Figure 1 ) of the battery pack housing 501 ( Figure 1 ). When the thickness of the cell block changes due to the expansion of the battery cells, strong pressure is applied to the fastening portion between the side frame 190 and the support structure 515. In Figure 4 , reference numeral 191’ denotes the side wall 191 deformed by the external force generated due to the expansion of the battery cells, and reference numeral 195’ denotes the flange portion 195 deformed by the external force generated due to the expansion of the battery cells. The external force generated due to the expansion of the battery cells 111 may cause damage to the bolts, the side frame 190, and / or the support structure 515.

[0081] Figure 5 is a cross-sectional view showing the side frame 120 according to an exemplary embodiment of the present disclosure.

[0082] In Figure 5 , reference numeral 210’ denotes the inner side wall 210 deformed by the external force generated due to the expansion of the battery cells 111. Refer to Figure 5 and Figure 1, when the thickness of the cell block 110 changes due to the expansion of the battery cell 111, the force acting in the first direction (X direction) between the fastening portions between the cell block 110 and the side frame 120 and the support structure 515 increases. According to an embodiment, this force can be weakened and distributed by a buffer space provided in the side wall portion 121. Since this force is weakened and distributed by the buffer space provided in the side wall portion 121, the pressure applied to the fastening portion between the side frame 120 and the support structure 515 can be reduced, and damage to fastening members (such as bolts BT), the side frame 120, and / or the support structure 515 can be reduced. Additionally, since this force is weakened and distributed by the buffer space provided in the side wall portion 121, the surface pressure applied to the cell block 110 or the battery cell 111 can be made more uniform. Therefore, the structural safety of the battery cell assembly 100 can be improved, and the safety and reliability of the battery cell assembly 100 and the battery pack 500 including the battery cell assembly 100 can be improved.

[0083] Figure 6 is a schematic diagram showing an electric mobile device (e.g., an electric vehicle 1000) equipped with a battery pack 1100 according to an exemplary embodiment of the present disclosure.

[0084] In Figure 6 , for simplicity of explanation, only the body frame 1200 forming the lower frame of the vehicle, the battery pack 1100 coupled to the body frame 1200, and the tires are shown. The battery pack 1100 may include the battery pack 500 described with reference to Figures 1 to 3 .

[0085] In the case of a typical battery pack, the battery cell assembly is mounted on the bottom of the battery pack housing. In an embodiment, the free volume FV (the first space, Figure 1) can be disposed below the battery cell assembly 100 of the battery pack 1100. That is, since there is no space between the battery cell assembly 100 and the battery pack cover 520, gas / flame generated in the battery cell assembly 100 can be prevented from being transmitted to the passenger compartment in the upper part of the vehicle. The gas / flame is guided to the free volume FV (first space) provided between the battery cell assembly 100 and the battery pack housing of the battery pack 1100. The gas / flame flows through the free volume FV (first space) and is discharged to the lower side of the vehicle through an exhaust portion (e.g., an exhaust device) installed in the battery pack 1100. In one embodiment of the present disclosure, the exhaust portion may be located on a side of the battery pack facing the rear side of the electric mobile device. In one embodiment of the present disclosure, the exhaust portion may include a pressure relief valve and / or a rupture valve. Further, according to this embodiment, since the free volume FV (first space) is provided between the battery pack housing and the battery cell assembly 100 in the battery pack 1100, damage to the battery cell assembly 100 can be prevented even when the battery pack housing is deformed.

[0086] According to an embodiment of the present disclosure, the battery pack 1100 and the electric vehicle 1000 having the battery pack 1100 can improve the safety of passengers. Further, the battery cell assembly 100 as a key component can be protected, and the durability of the battery pack 1100 and the electric vehicle 1000 can be improved.

[0087] As described above, the present disclosure has been described in more detail through the drawings and embodiments. However, since the configurations described in the embodiments or the drawings herein are only one embodiment of the present disclosure and do not represent the overall technical concept of the present disclosure, it should be understood that the present disclosure encompasses various equivalents, modifications, and substitutions at the time of filing of this application.

[0088] [Description of Reference Numerals]

[0089] 100: Battery cell assembly, 110: Cell block

[0090] 111: Battery cell, 120: Side frame

[0091] 121: Side wall portion, 125: Flange portion

[0092] 131: Top cover plate, 135: Bottom cover plate

[0093] 500: Battery pack, 510: Lower housing

[0094] 515: Support structure, 520: Battery pack cover

Claims

1. A battery cell assembly, the battery cell assembly comprising: A cell block, the cell block including a plurality of battery cells; And A side frame, the side frame being disposed on one side surface of the cell block, Wherein the side frame includes a side wall portion and a flange portion, the flange portion being disposed on the side wall portion on a side opposite to the cell block and configured to be fastened to an external support structure, and Wherein the side wall portion includes a hollow space formed internally through the side wall portion.

2. The battery cell assembly according to claim 1, wherein, The hollow space includes an upper buffer space and a lower buffer space, Wherein the side wall portion includes an inner side wall, a first outer side wall, and a second outer side wall, the inner side wall facing the one side surface of the cell block, the first outer side wall being spaced apart from an upper portion of the inner side wall and the upper buffer space being located between the upper portion of the inner side wall and the first outer side wall, the second outer side wall being spaced apart from a lower portion of the inner side wall and the lower buffer space being located between the lower portion of the inner side wall and the second outer side wall, Wherein the flange portion is connected to the first outer side wall and the second outer side wall, Wherein each of the first outer side wall and the second outer side wall is spaced apart from the inner side wall in a first direction, and Wherein the first outer side wall is spaced apart from the second outer side wall.

3. The battery cell assembly according to claim 2, wherein, The plurality of battery cells are stacked in the first direction.

4. The battery cell assembly according to claim 2, wherein, The side wall portion further includes: An upper wall, the upper wall extending between an upper end portion of the inner side wall and an upper end portion of the first outer side wall; and A lower wall, the lower wall extending between a lower end portion of the inner side wall and a lower end portion of the second outer side wall, Wherein the upper buffer space is defined by the upper portion of the inner side wall, the upper wall, and the first outer side wall, and Wherein the lower buffer space is defined by the lower portion of the inner side wall, the lower wall, and the second outer side wall.

5. The battery cell assembly according to claim 1, wherein, The upper buffer space communicates with the lower buffer space through an intermediate buffer space located near a middle portion of the inner side wall, Wherein the flange portion includes an internal space through which a fastening member passes, and Wherein the internal space of the flange portion communicates with the intermediate buffer space.

6. The battery cell assembly according to claim 5, wherein, The flange portion includes: An upper fastening plate, the fastening member passing through the upper fastening plate; A lower fastening plate, the fastening member passing through the lower fastening plate, and the lower fastening plate being spaced apart from the upper fastening plate, the internal space being located between the upper fastening plate and the lower fastening plate; and A connecting plate, the connecting plate connecting the upper fastening plate to the lower fastening plate.

7. The battery cell assembly according to claim 6, wherein, The flange portion further includes: A reinforcing rib, the reinforcing rib extending from the upper fastening plate to the lower fastening plate and being closer to the inner side wall of the side wall portion than the connecting plate.

8. The battery cell assembly according to claim 1, the battery cell assembly further comprising: A bottom cover plate, the bottom cover plate being located below the cell block and coupled to a lower end portion of the side wall portion.

9. The battery cell assembly according to claim 1, the battery cell assembly further comprising: A top cover plate, the top cover plate being located on the battery cell block and connected to the upper end portion of the side wall portion.

10. The battery cell assembly according to claim 9, wherein, The top cover plate includes a cooling channel.

11. A battery pack, the battery pack comprising: A battery pack housing, the battery pack housing including a support structure; and A battery cell assembly, the battery cell assembly being received in the battery pack housing, wherein the battery cell assembly includes a battery cell block and a side frame, the battery cell block including a plurality of battery cells, the side frame being disposed on one side surface of the battery cell block, wherein the side frame includes a side wall portion and a flange portion, the flange portion being disposed on the side wall portion on a side opposite to the battery cell block and fastened to the support structure, wherein the side wall portion includes a hollow space formed through the interior of the side wall portion.

12. The battery pack according to claim 11, wherein, The hollow space includes an upper buffer space, an intermediate buffer space, and a lower buffer space, wherein the side wall portion includes an inner side wall, a first outer side wall, and a second outer side wall, the inner side wall facing the one side surface of the battery cell block, the first outer side wall being spaced apart from an upper portion of the inner side wall and the upper buffer space being located between the upper portion of the inner side wall and the first outer side wall, the second outer side wall being spaced apart from a lower portion of the inner side wall and the lower buffer space being located between the lower portion of the inner side wall and the second outer side wall, wherein the flange portion is connected to the first outer side wall and the second outer side wall, wherein the upper buffer space communicates with the lower buffer space through the intermediate buffer space, wherein the flange portion includes: An upper fastening plate, a fastening member passing through the upper fastening plate; A lower fastening plate, the fastening member passing through the lower fastening plate, and the lower fastening plate being spaced apart from the upper fastening plate, and an internal space being located between the upper fastening plate and the lower fastening plate; and A connecting plate, the connecting plate connecting the upper fastening plate to the lower fastening plate, and wherein the internal space communicates with the intermediate buffer space.

13. The battery pack according to claim 12, wherein, The battery cell assembly further includes: A bottom cover plate, the bottom cover plate being located below the battery cell block; and A top cover plate, the top cover plate being located on top of the battery cell block and including a cooling channel.

14. The battery pack according to claim 13, wherein, The battery cell assembly and the bottom wall of the battery pack housing are spaced apart from each other to form a first space.

15. The battery pack according to claim 13, wherein, The side wall portion further includes: An upper wall, the upper wall extending between an upper end portion of the inner side wall and an upper end portion of the first outer side wall and connected to the top cover plate; and A lower wall, the lower wall extending between a lower end portion of the inner side wall and a lower end portion of the second outer side wall and connected to the bottom cover plate.

16. The battery pack according to claim 14, wherein, Each of the plurality of battery cells is a pouch-type battery cell.

17. The battery pack according to claim 16, wherein, The sealed portion of the pouch of the pouch-type battery cells in the battery cell block faces the first space.

18. The battery pack according to claim 14, wherein, Each of the plurality of battery cells is a cylindrical battery cell or a prismatic battery cell including an exhaust portion.

19. The battery pack according to claim 18, wherein, The exhaust portion of the cylindrical battery cell or the prismatic battery cell faces the first space.

20. An electric mobile device including a battery pack, the battery pack including: A battery pack housing including a support structure; and a battery cell assembly received in the battery pack housing, wherein the battery cell assembly includes a cell block and a side frame, the cell block includes a plurality of battery cells, and the side frame is disposed on one side surface of the cell block, wherein the side frame includes a side wall portion and a flange portion, the flange portion is disposed on the side wall portion on a side opposite to the cell block and fastened to the support structure, wherein the side wall portion includes a hollow space formed through an interior of the side wall portion.

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