Battery cell assembly and battery pack including same

Abstract

The technical idea of ​​the present invention provides a battery cell assembly including a cell block including a plurality of battery cells and a side frame on one side of the cell block, the side frame including a side wall portion and a flange portion arranged on the side wall portion opposite the cell block and configured to be fastened to an external support structure, the side wall portion including an empty space formed throughout its interior.

Description

[Technical Field]

[0001] The present invention relates to a battery cell assembly and a battery pack including the same. [Background technology]

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of wireless devices, such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0003] As secondary batteries are used in mobility, there is a growing demand for their safety. Research into technologies to improve the safety of secondary batteries is essential, as a fire or other accident involving a secondary battery used in mobility could put the driver's life at risk.

[0004] The discussion of the background of the invention provided herein is intended to generally present the contents of the present disclosure. Unless otherwise expressly stated herein, the material described in this section is not prior art to the claims of this application and is not admitted as prior art or an admission of prior art by inclusion in this section. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the technical idea of ​​the present invention is to provide a battery cell assembly and a battery pack with improved safety.

[0006] These and other objects and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from exemplary embodiments of the present disclosure. It will also be readily apparent that the objects and advantages of the present disclosure can be realized by the means and combinations thereof as set forth in the appended claims. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a battery cell assembly including a cell block including a plurality of battery cells and a side frame on one side of the cell block, the side frame including a side wall portion and a flange portion disposed on the side wall portion opposite the cell block and configured to be fastened to an external support structure, and the side wall portion including a hollow space formed throughout its interior.

[0008] In an exemplary embodiment, the empty space includes an upper buffer space and a lower buffer space, the side wall portion includes an inner wall facing the one side of the cell block, a first outer wall separating an upper portion of the inner wall with the upper buffer space therebetween, and a second outer wall separating a lower portion of the inner wall with the lower buffer space therebetween, the flange portion being connected to the first outer wall and the second outer wall, the first outer wall and the second outer wall being separated from the inner wall in a first direction, and the first outer wall being separated from the second outer wall.

[0009] In an exemplary embodiment, the plurality of battery cells are stacked in the first direction.

[0010] In an exemplary embodiment, the side wall portion further includes an upper wall extending between an upper end of the inner wall and an upper end of the first outer wall, and a bottom wall extending between a lower end of the inner wall and a lower end of the second outer wall, wherein the upper buffer space is defined by the upper part of the inner wall, the upper wall, and the first outer wall, and the lower buffer space is defined by the lower part of the inner wall, the bottom wall, and the second outer wall.

[0011] In an exemplary embodiment, the upper buffer space communicates with the lower buffer space via an intermediate buffer space located near the middle of the inner wall, and the flange portion has an internal space through which a fastening member passes, and the internal space of the flange portion communicates with the intermediate buffer space.

[0012] In an exemplary embodiment, the flange portion includes an upper fastening plate through which the fastening member passes, a lower fastening plate through which the fastening member passes and which is separated from the upper fastening plate with the internal space therebetween, and a connecting plate connecting the upper fastening plate and the lower fastening plate.

[0013] In an exemplary embodiment, the flange portion further includes a reinforcing rib extending from the upper fastening plate to the lower fastening plate and adjacent to the inner wall of the side wall portion from the connecting plate.

[0014] In an exemplary embodiment, the storage device further includes a lower cover plate located below the cell block and coupled to a lower end of the side wall portion.

[0015] In an exemplary embodiment, the storage device further includes an upper cover plate located on the cell block and coupled to an upper end of the side wall portion.

[0016] In an exemplary embodiment, the top cover plate is characterized by including cooling channels.

[0017] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a battery pack including a pack housing including a support structure and a battery cell assembly accommodated in the pack housing, wherein the battery cell assembly includes a cell block including a plurality of battery cells and a side frame on one side of the cell block, the side frame including a side wall portion and a flange portion disposed on the side wall portion opposite the cell block and fastened to the support structure, and the side wall portion includes an empty space formed throughout its interior.

[0018] In an exemplary embodiment, the empty space includes an upper buffer space, a middle buffer space, and a lower buffer space, the side wall portion includes an inner wall facing the one side of the cell block, a first outer wall separating the upper part of the inner wall with the upper buffer space therebetween, and a second outer wall separating the lower part of the inner wall with the lower buffer space therebetween, the flange portion is connected to the first outer wall and the second outer wall, the upper buffer space communicates with the lower buffer space via the middle buffer space, the flange portion includes an upper fastening plate through which a fastening member passes, a lower fastening plate separating the upper fastening plate with the fastening member passing therethrough and with an internal space therebetween, and a connecting plate connecting the upper fastening plate and the lower fastening plate, and the internal space communicates with the intermediate buffer space.

[0019] In an exemplary embodiment, the battery cell assembly is characterized by including a lower cover plate underlying the cell block and an upper cover plate positioned above the top of the cell block and including cooling channels.

[0020] In an exemplary embodiment, the battery cell assembly and the bottom wall of the pack housing are characterized by being spaced apart from one another to form a first space.

[0021] In an exemplary embodiment, the side wall portion further includes an upper wall extending between an upper end of the inner wall and an upper end of the first outer wall and coupled to the upper cover plate, and a bottom wall extending between a lower end of the inner wall and a lower end of the second outer wall and coupled to the lower cover plate.

[0022] In an exemplary embodiment, each of the plurality of battery cells may be a pouch-type battery cell.

[0023] In the exemplary embodiment, the sealed portion of the pouch-type battery cell in the cell block is characterized by facing the first space.

[0024] In an exemplary embodiment, each of the plurality of battery cells is a cylindrical battery cell or a prismatic battery cell and is characterized by including a vent portion.

[0025] In an exemplary embodiment, the venting portion of the cylindrical battery cell or the prismatic battery cell is characterized by facing the first space.

[0026] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides an electric mobility device including a battery pack, the battery pack including a pack housing including a support structure and a battery cell assembly housed in the pack housing, the battery cell assembly including a cell block including a plurality of battery cells and a side frame arranged on one side of the cell block, the side frame including a side wall portion and a flange portion arranged on the side wall portion opposite the cell block and fastened to the support structure, and the side wall portion including an empty space formed throughout its interior.

[0027] According to an exemplary embodiment of the present disclosure, the force acting between the cell block and the fastening portion that fastens the battery cell assembly to the pack housing may increase due to swelling of the battery cells, but the force can be attenuated and dispersed by the buffer space provided in the side wall portion of the side frame. The attenuation and dispersion of the force by the buffer space provided in the side wall portion of the side frame reduces the pressure acting on the fastening portion between the battery cell assembly and the pack housing, thereby reducing damage to the fastening portion between the battery cell assembly and the pack housing. Furthermore, the attenuation and dispersion of the force by the buffer space provided in the side wall portion of the side frame makes the surface pressure acting on the cell block or the battery cells more uniform. This improves the structural stability of the battery cell assembly and the safety and reliability of the battery cell assembly and the battery pack including the same.

[0028] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Effects of the Invention]

[0029] According to an embodiment, the force may be attenuated and dispersed by the buffer space provided in the side wall portion. The force is attenuated and dispersed by the buffer space provided in the side wall portion, thereby reducing pressure acting on fastening portions between the side frame and the support structure and reducing damage to fastening members such as bolts, the side frame, and / or the support structure. Furthermore, the force is attenuated and dispersed by the buffer space provided in the side wall portion, thereby making the surface pressure acting on the cell block or the battery cells more uniform. This may improve the structural stability of the battery cell assembly, and may improve the safety and reliability of the battery cell assembly and a battery pack including the same. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view illustrating a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing a side frame of a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing a side frame according to a comparative example. [Figure 5] FIG. 2 is a cross-sectional view showing a side frame according to an exemplary embodiment of the present invention. [Figure 6] 1 is a schematic diagram illustrating an electric vehicle equipped with a battery pack according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concepts of terms to best describe his own invention.

[0032] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0033] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0034] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0035] Fig. 1 is a cross-sectional view showing a battery pack 500 according to an exemplary embodiment of the present invention. Fig. 2 is a perspective view showing a battery cell assembly 100 according to an exemplary embodiment of the present invention. Fig. 3 is a cross-sectional view showing a side frame 120 of the battery cell assembly 100 according to an exemplary embodiment of the present invention.

[0036] 1 to 3, a battery pack 500 may include a pack housing 501 and a battery cell assembly 100 mounted in the pack housing 501. The battery pack 500 may include one or more battery cell assemblies 100 mounted in the 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).

[0037] The pack housing 501 may include a lower housing 510 having an accommodation space in which the battery cell assemblies 100 are accommodated, and a pack cover 520 coupled onto the lower housing 510 to cover the lower housing 510 in which the battery cell assemblies 100 are accommodated. The accommodation space of the lower housing 510 may be defined by a bottom wall 511 facing the lower surfaces of the cell blocks 110 of the individual battery cell assemblies 100, and side walls 513 located on the edges of the bottom wall 511.

[0038] The battery cell assembly 100 may include a cell block 110 , a side frame 120 , an upper cover plate 131 , and a lower cover plate 135 .

[0039] The cell block 110 may include multiple battery cells 111. Each battery cell 111 is the 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 case. The electrode assembly housed in the case may include a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. Depending on the assembly form, the electrode assembly may be either a jelly roll type or a stack type. A jelly roll type electrode assembly may include a wound structure of a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly may include multiple positive electrodes, multiple negative electrodes, and multiple separators interposed therebetween, which are stacked in sequence. 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.

[0040] The plurality of battery cells 111 may be connected in series and / or parallel. For example, the plurality of battery cells 111 may be connected in series to each other. For another example, the plurality of battery cells 111 may be connected in parallel to each other. For another example, when a set of two or more battery cells 111 connected in parallel to each other is defined as a bank, one bank consisting of two or more battery cells 111 connected in parallel to each other and another bank consisting of two or more battery cells 111 connected in parallel to each other may be connected in series.

[0041] 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 cases, such as a pouch, a cylindrical can, or a prismatic can. The electrode assembly of a pouch-type battery cell is housed in a pouch case including an aluminum laminate sheet. The electrode assembly of a cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of a prismatic battery cell is housed in a prismatic metal can. Each battery cell 111 may include a vent facing the first space. For example, the vent of each battery cell 111 may be provided in the cell case of the battery cell 111. When the pressure inside the cell case of each battery cell 111 exceeds a certain level, gas inside the cell case of each battery cell 111 may be discharged to the first space through the vent 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.

[0042] In an exemplary embodiment, each battery cell 111 corresponds to a pouch-type battery cell, and multiple battery cells 111 may be stacked in a first direction (X direction) within one battery cell assembly 100 (e.g., FIG. 1 ). In an exemplary embodiment, each battery cell assembly 100 includes multiple battery cells 111 each having a length (thickness) along the first direction (X direction) that is shorter than its length along the second direction (Y direction), and multiple 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 a sealed portion of the pouch within the pouch-type battery cell may be formed to face the first space to easily vent gas and / or flame from the battery cell. When pressure within the pouch exceeds a certain level, the sealed portion of the pouch may be partially broken, and gas within the pouch may be vented to the first space through the broken portion of the sealed portion.

[0043] When viewed from above, the cell block 110 may have a rectangular shape whose length along a first direction (X direction) is shorter than its length along a second direction (Y direction). In this case, the cell block 110 may have first and second side surfaces opposite each other in the first direction (X direction), front and back surfaces opposite each other in the second direction (Y direction), and top and bottom surfaces opposite each other in a third direction (Z direction).

[0044] A busbar frame on which a busbar is mounted may be disposed on each of the front and rear surfaces of the cell block 110. A plurality of busbars may be mounted on the busbar frame on the front surface of the cell block 110, and a plurality of busbars may be mounted on the busbar frame on the rear surface of the cell block 110. The battery cell assembly 100 may include an end plate 141 for covering the busbar frame connected to the front surface or the rear surface of the cell block 110.

[0045] The bus bars may be coupled to the electrode leads of the battery cells 111. For example, the bus bars may be coupled to the electrode leads of the battery cells 111 by welding. For example, each bus bar may be an inter-bus bar that is coupled to an electrode lead coupled to different battery cells 111 belonging to the cell block 110 and electrically connects the different battery cells 111. For example, each bus bar may be a terminal bus bar that electrically connects the battery cell assembly 100 to another external electrical device.

[0046] In an exemplary embodiment, the battery cell assembly 100 may include a single cell block 110. In an exemplary embodiment, the battery cell assembly 100 may include a cell block array composed of a plurality of cell blocks 110 arranged in a second direction (Y direction). For example, the battery cell assembly 100 may include two cell blocks 110 arranged in the second direction (Y direction). As an example, the battery cell assembly 100 may include a first cell block and a second cell block arranged in the second direction (Y direction) and electrically connected to each other.

[0047] The side frames 120 may be provided on both side portions of the cell block 110. The battery cell assembly 100 may be fastened to the pack housing 501 by a side mounting method in which the battery cell assembly 100 is fastened to a support structure 515 of the pack housing 501 via the side frames 120.

[0048] The side frame 120 may include a side wall 121 connected to a side surface of the cell block 110 and a flange 125 fastened to and supported by a support structure 515 of the pack housing 501 by fastening members such as bolts BT. The side wall 121 and the flange 125 are each part of the side frame 120, and the side wall 121 and the flange 125 may form a single body. For example, the side frame 120 may be formed by an extrusion process, and the side wall 121 and the flange 125 may be made of the same material. The side wall 121 may be closer to the cell block 110 than the flange 125 and may extend in a second direction (Y direction) and a third direction (Z direction) along the side surface of the cell block 110. A plurality of flanges 125 may be connected to the side wall 121, and the plurality of flanges 125 may be arranged spaced apart in the second direction (Y direction).

[0049] The sidewall portion 121 may include an empty space formed throughout its interior. The empty space may include an upper buffer space 241, a middle buffer space 245, and a lower buffer space 243. The sidewall portion 121 may include an inner wall 210 facing a side surface of the cell block 110, a first outer wall 221 separated from an upper portion of the inner wall 210 with the upper buffer space 241 therebetween, a second outer wall 223 separated from a lower portion of the inner wall 210 with the lower buffer space 243 therebetween, a top wall 231 extending between an upper end (or upper edge) of the inner wall 210 and an upper end or upper edge of the first outer wall 221, and a bottom wall 233 extending between a lower end (or lower edge) of the inner wall 210 and a lower end (or lower edge) of the second outer wall 223. The first outer wall 221 and the second outer wall 223 may be spaced apart in a third direction (Z direction).

[0050] The inner wall 210 may have a flat plate shape. For example, the inner wall 210 may have a flat plate shape perpendicular to the first direction (X direction). The inner wall 210 may have an upper portion facing the first outer wall 221 in the first direction (X direction), a lower portion facing the second outer 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 wall 210. The thickness of the inner wall 210 (i.e., the thickness of the inner wall 210 along the first direction (X direction)) may be generally uniform. The thickness of the inner wall 210 may be in the range of several millimeters, for example, in the range of 1 mm to 4 mm.

[0051] 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 along the first direction (X direction)) may be generally uniform. The thickness of the first outer wall 221 may be in the range of several millimeters, for example, 1 mm to 4 mm. The distance between the first outer wall 221 and the inner wall 210 along the first direction (X direction) may be generally uniform. For example, the distance between the first outer wall 221 and the inner wall 210 along the first direction (X direction) may be in the range of several millimeters.

[0052] The first outer wall 221 is spaced apart from the inner wall 210 in the first direction (X direction), so that an 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 an 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 along the first direction (X direction) (i.e., the distance along the first direction (X direction) between the inner wall 210 and the first outer wall 221) may be uniform. The width of the upper buffer space 241 along the first direction (X direction) may be in the range of several millimeters, for example, 2 mm to 6 mm, or 3 mm to 5 mm.

[0053] 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 in the first direction (X direction) from a lower portion of the inner wall 210. The thickness of the second outer wall 223 (i.e., the thickness of the second outer wall 223 along the first direction (X direction)) may be generally uniform. The thickness of the second outer wall 223 may be in the range of several millimeters, for example, in the range of 1 mm to 4 mm. The thickness of the first outer wall 221 and the thickness of the second outer wall 223 may be generally the same. The distance between the second outer wall 223 and the inner wall 210 along the first direction (X direction) may be generally uniform. For example, the distance between the second outer wall 223 and the inner wall 210 along the first direction (X direction) may be in the range of several millimeters. The distance along the first direction (X direction) between the second outer wall 223 and the inner wall 210 may be the same as or similar to the distance along the first direction (X direction) between the first outer wall 221 and the inner wall 210.

[0054] The second outer wall 223 is spaced apart from the inner wall 210 in the first direction (X direction), thereby providing a lower buffer space 243 between the second outer wall 223 and the inner wall 210. The lower buffer space 243 may be defined by a lower portion of the inner wall 210, the second outer wall 223, and a bottom wall 233. The width of the lower buffer space 243 along the first direction (X direction) (i.e., the distance along the first direction (X direction) between the inner wall 210 and the second outer wall 223) may be uniform. The width of the lower buffer space 243 along the first direction (X direction) may be in the range of several millimeters, for example, 2 mm to 6 mm, or 3 mm to 5 mm. The width of the lower buffer space 243 along the first direction (X direction) may be the same as the width of the upper buffer space 241 along the first direction (X direction).

[0055] The upper buffer space 241 and the lower buffer space 243 may be in communication with each other. More specifically, the upper buffer space 241 may be in communication with the lower buffer space 243 via an intermediate buffer space 245 adjacent to the middle portion of the inner wall 210. The intermediate buffer space 245 may 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 may be in communication with each other to form a single integrated buffer space, i.e., the hollow space.

[0056] The flange portion 125 may have an internal space 259 that communicates with the intermediate buffer space 245. The flange portion 125 may include an upper fastening plate 251, a lower fastening plate 253, and a connecting plate 255.

[0057] The upper fastening plate 251 may be connected to a lower end of the first outer wall 221 and extend in the first direction (X direction) from the lower end of the first outer wall 221. The upper fastening plate 251 may have fastening holes through which the bolts BT pass. The upper fastening plate 251 may 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 along the third direction (Z direction)) may be in the range of several millimeters, for example, in the range of 2 mm to 5 mm.

[0058] The lower fastening plate 253 may be connected to an upper end of the second outer wall 223 and extend in the first direction (X direction) from the upper end of the second outer wall 223. The upper fastening plate 251 and the lower fastening plate 253 may be spaced apart in the third direction (Z direction) with an internal space 259 therebetween. The lower fastening plate 253 may have fastening holes through which the 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 be in the range of several millimeters, for example, 2 mm to 5 mm.

[0059] 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 in the third direction (Z direction) from an outer edge of the upper fastening plate 251 to an outer edge of the lower fastening plate 253. An 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. The bolt BT may pass through the upper fastening plate 251 and the lower fastening plate 253 and pass through the internal space 259 of the flange portion 125.

[0060] The flange portion 125 may further include a reinforcing rib 257 for enhancing the rigidity of the side frame 120. The reinforcing rib 257 may extend across the internal space 259 of the flange portion 125 in the third direction (Z direction) and extend in the third direction (Z direction) from the lower surface of the upper fastening plate 251 to the upper surface of the lower fastening plate 253. The reinforcing rib 257 may be located between the inner wall 210 of the side wall portion 121 and the connecting plate 255, or may be located closer to the inner wall 210 of the side wall portion 121 than the connecting plate 255.

[0061] The upper cover plate 131 may cover the upper surface of the cell block 110. The upper cover plate 131 may be coupled to the upper ends of the side frames disposed on both sides of the cell block 110. For example, one side of the upper cover plate 131 may be coupled to the upper ends of the side frames by welding. For example, one side of the upper cover plate 131 may be coupled to the upper wall 231 of the side frame 120.

[0062] The upper cover plate 131 may be attached to the upper surface of the cell block 110 or may be thermally coupled to the cell block 110. The upper cover plate 131 may be attached to the upper surface of the cell block 110 via a thermally conductive adhesive layer interposed between the upper cover plate 131 and the upper surface of the cell block 110. For example, the thermally conductive adhesive layer may include a thermal interface material (TIM).

[0063] The upper cover plate 131 may have cooling channels 1311 configured to allow a cooling fluid to flow therethrough and may be configured to cool the cell block 110. The upper cover plate 131 may be referred to as a cooling plate. The upper cover plate 131 may be thermally coupled to the cell block 110 via a thermally conductive adhesive layer and configured to cool the cell block 110. A cooling fluid provided from the outside of the battery cell assembly 100 may flow into the cooling channels 1311 through an inlet of the cooling channels 1311, flow along the cooling channels 1311, and then flow out to the outside through an outlet of the cooling channels 1311. While the cooling fluid flows along the cooling channels 1311, cooling of the battery cell assembly 100 may be performed. For example, the upper cover plate 131 may be manufactured by bonding two plates, and the cooling channels 1311 may include a space defined between the two plates.

[0064] The lower 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 lower cover plate 135 may be coupled to the lower end of each of the side frames disposed on both sides of the cell block 110. For example, one side of the lower cover plate 135 may be coupled to the lower end of the side frame by welding. For example, one side of the lower cover plate 135 may be coupled to the bottom wall 233 of the side frame 120. The lower cover plate 135, the upper cover plate 131, and the side frame 120 may together form a case surrounding the cell block 110. The lower cover plate 135 may include a venting passage for exhausting high-temperature gas generated by the cell block 110 to the space below the cell block 110.

[0065] When the battery pack 500 is mounted on a vehicle, a passenger compartment where passengers board may be located above the pack cover 520, and the ground on which the vehicle runs may be located below the lower housing 510.

[0066] The battery cell assembly 100 is supported by a support structure 515 provided on the bottom wall 511 of the lower housing 510 in a side-mounting manner, and a free volume FV (first space) may be provided between the bottom wall 511 of the lower housing 510 and the battery cell assembly 100. Gas and flames generated in a thermal runaway situation may move through the free volume FV. That is, the free volume FV (first space) serves as a venting passage through which high-temperature gas and flames can move.

[0067] In addition, even when a strong impact occurs due to foreign objects being thrown onto the underside of the vehicle while driving on hard ground such as an unpaved road, the impact can be absorbed via the free volume FV (first space), thereby preventing damage to the plurality of battery cell assemblies 100 due to the impact. The free volume FV (first space) is an empty space between each of the plurality of battery cell assemblies 100 and the lower housing 510, and when the lower housing 510 is deformed toward the battery cell assembly 100 due to an impact applied to the underside of the vehicle, the free volume FV (first space) can be used as a space that allows the lower housing 510 to deform to a certain extent.

[0068] The height of the free volume FV (first space) and the distance between the bottom wall of the lower housing 510 and the battery cell assembly 100 may be set sufficiently to absorb external impacts. The height of the free volume FV may be determined taking into consideration the dimensions and rigidity of the vehicle frame, the dimensions and rigidity of the lower housing 510, the dimensions of the battery pack 500, the amount of gas generated and the rate of gas discharge 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 (first space) may be relatively small. Furthermore, when the thickness or rigidity of the vehicle frame or the bottom wall of the lower housing 510 is relatively small, there is a high possibility of deformation of the bottom wall of the lower housing 510. Therefore, to protect the battery cell assembly 100, at least one of the size and height of the free volume FV (first space) may be relatively increased. Furthermore, 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 (first space) may be ensured. When the size of the battery pack 500 is relatively small, the height of the free volume FV (first space) that can be secured may be relatively low, and the thickness and rigidity of the bottom wall of the lower housing 510 may need to be relatively increased. Also, if the height of the free volume FV (first space) is too low, the gas discharge path becomes small, and the internal pressure of the battery pack 500 may rise rapidly during thermal runaway. Therefore, the size and height of the free volume FV (first space) may be determined taking into consideration the amount of gas generated and the discharge speed.

[0069] The maximum height of the free volume FV (first space) may be determined depending on the degree of damage to the battery cell 111 included in the battery cell assembly 100. For example, if the damage tolerance limit of the battery cell 111 is 1 mm, the free volume FV may be determined so that the battery cell 111 does not deform more than 1 mm when the lower housing 510 is deformed and presses the lower surface of the battery cell 111. In this case, the amount of deformation of the lower housing 510 may vary depending on the thickness and rigidity of the lower housing 510. Therefore, the size and height of the free volume FV (first space) may be determined taking into consideration all of the damage tolerance limit of the battery cell 111 and the thickness and rigidity of the lower housing 510.

[0070] In an exemplary embodiment, the upper surface of the battery cell assembly 100 may be in close contact with the lower surface of the pack cover 520. If there is a space between the battery cell assembly 100 and the pack cover 520, high-temperature gas may be introduced into the space between one battery cell assembly 100 and the pack cover 520 during thermal runaway, and heat and flame may propagate to other adjacent battery cell assemblies 100. In addition, heat and flame may be transmitted to the pack cover 520, potentially affecting the cabin room above the pack cover 520. Therefore, by bringing the upper surface of the battery cell assembly 100 and the lower surface of the pack cover 520 into close contact, gas and flame generated inside the battery pack 500 can be guided to the free volume FV (first space).

[0071] FIG. 4 is a cross-sectional view showing a side frame 190 according to a comparative example.

[0072] Referring to FIG. 4, a side frame 190 according to the comparative example may include a side wall 191 connected to one side of a cell block and a flange portion 195 connected to the side wall 191. The side frame 190 may be fastened to a support structure (515 in FIG. 1) of a pack housing (501 in FIG. 1) using bolts. When the thickness of the cell block changes due to swelling of the battery cells, strong pressure acts on the fastening portion between the side frame 190 and the support structure 515. In FIG. 4, reference numeral 191′ denotes the side wall 191 that is deformed by an external force generated by the swelling of the battery cells, and reference numeral 195′ denotes the flange portion 195 that is deformed by the external force generated by the swelling of the battery cells. The external force generated by the swelling of the battery cells 111 may cause damage to the bolts, the side frame 190, and / or the support structure 515.

[0073] FIG. 5 is a cross-sectional view illustrating a side frame 120 according to an exemplary embodiment of the present invention.

[0074] In FIG. 5, reference numeral 210′ ​​denotes the inner wall 210 that is deformed by an external force generated by swelling of the battery cell 111. Referring to FIG. 5 together with FIG. 1, when the thickness of the cell block 110 changes due to swelling of the battery cell 111, the force acting in the first direction (X direction) between the cell block 110 and the fastening portion between the side frame 120 and the support structure 515 increases. According to an embodiment, the force may be attenuated and dispersed by a buffer space provided in the side wall portion 121. Because the force is attenuated and dispersed by the buffer space provided in the side wall portion 121, pressure acting on the fastening portion between the side frame 120 and the support structure 515 is reduced, thereby reducing damage to fastening members such as bolts BT, the side frame 120, and / or the support structure 515. In addition, because the force is attenuated and dispersed by the buffer space provided in the side wall portion 121, the surface pressure acting on the cell block 110 or the battery cell 111 may be more uniform. This can improve the structural stability of the battery cell assembly 100, and can improve the safety and reliability of the battery cell assembly 100 and the battery pack 500 including the same.

[0075] FIG. 6 is a schematic diagram illustrating an electric vehicle 1000 equipped with a battery pack 1100 according to an exemplary embodiment of the present invention.

[0076] 6, for simplicity of illustration, only the vehicle body frame 1200 forming the lower skeleton of the vehicle, the battery pack 1100 coupled to the vehicle body frame 1200, and tires are shown. The battery pack 1100 can include the battery pack 500 described with reference to FIGS. 1 to 3.

[0077] In a typical battery pack, a battery cell assembly is installed at the bottom of the pack housing of the battery pack. In an embodiment, a free volume (see FV in FIG. 1) may be provided below the battery cell assembly 100 of the battery pack 1100. That is, there is no space between the battery cell assembly 100 and the pack cover 520, preventing gas and flame generated in the battery cell assembly 100 from being transmitted to the cabin room above the vehicle. The gas and flame are guided to a free volume FV (first space) provided in the battery cell assembly 100 and the pack housing of the battery pack 1100. The gas / flame flows through the free volume FV (first space) and can be discharged to the underside of the vehicle through a gas exhaust unit (e.g., an exhaust device) installed in the battery pack 1100. In an embodiment of the present disclosure, the gas vent unit may be located on one side of the pack facing the rear of the electric mobility device. In an embodiment of the present disclosure, the gas vent unit may include a relief valve and / or a rupture valve. In addition, according to this embodiment, a free volume FV (first space) is provided between the battery cell assembly 100 and the pack housing within the battery pack 1100, so that even if the pack housing is deformed, damage to the battery cell assembly 100 can be prevented.

[0078] According to the embodiment of the present invention, the battery pack 1100 and the electric vehicle 1000 including the same can enhance passenger safety, protect the battery cell assembly 100, which is a core component, and improve the durability of the battery pack 1100 and the electric vehicle 1000.

[0079] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0080] 100: Battery cell assembly 110: Cell Block 111: Battery cell 120: Side frame 121: Side wall 125: Flange part 131: Upper cover plate 135: Lower cover plate 500: Battery pack 510: Lower housing 515: Support structure 520: Pack cover

Claims

1. a cell block including a plurality of battery cells; a side frame on one side of the cell block, the side frame includes a side wall portion and a flange portion disposed on the side wall portion opposite the cell block and configured to be fastened to an external support structure; The sidewall portion includes an empty space formed throughout the interior of the battery cell assembly.

2. the empty space includes an upper buffer space and a lower buffer space, the side wall portion includes an inner wall facing the one side of the cell block, a first outer wall spaced apart from an upper portion of the inner wall with the upper buffer space therebetween, and a second outer wall spaced apart from a lower portion of the inner wall with the lower buffer space therebetween; the flange portion is connected to the first outer wall and the second outer wall, the first outer wall and the second outer wall are each spaced apart from the inner wall in a first direction; The battery cell assembly of claim 1 , wherein the first outer wall is spaced apart from the second outer wall.

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

4. The side wall portion is an upper wall extending between an upper end of the inner wall and an upper end of the first outer wall; a bottom wall extending between a lower end of the inner wall and a lower end of the second outer wall, the upper buffer space is defined by the upper portion of the inner wall, the upper wall, and the first outer wall; The battery cell assembly of claim 2 , wherein the lower buffer space is defined by the lower portion of the inner wall, the bottom wall, and the second outer wall.

5. the upper buffer space communicates with the lower buffer space via an intermediate buffer space located near a middle portion of the inner wall; The flange portion has an internal space through which a fastening member passes, The battery cell assembly according to claim 2 , wherein the internal space of the flange portion communicates with the intermediate buffer space.

6. The flange portion is an upper fastening plate through which the fastening member passes; a lower fastening plate through which the fastening member passes and which is spaced apart from the upper fastening plate with the internal space therebetween; a connecting plate connecting the upper fastening plate and the lower fastening plate; 6. The battery cell assembly of claim 5, comprising:

7. The flange portion is a reinforcing rib extending from the upper fastening plate to the lower fastening plate and further adjacent to the inner wall of the side wall portion than the connecting plate; The battery cell assembly of claim 6 further comprising:

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

9. The battery cell assembly according to claim 1 , further comprising an upper cover plate located on the cell block and coupled to an upper end of the side wall portion.

10. The battery cell assembly of claim 9 , wherein the top cover plate includes cooling channels.

11. a pack housing including a support structure; a battery cell assembly housed in the pack housing; Including, The battery cell assembly a cell block including a plurality of battery cells; a side frame on one side of the cell block; Including, the side frame includes a side wall portion and a flange portion that is disposed on the side wall portion opposite the cell block and is fastened to the support structure; The side wall portion includes an empty space formed throughout the interior of the battery pack.

12. the empty space includes an upper buffer space, a middle buffer space, and a lower buffer space; The side wall portion includes an inner wall facing the one side of the cell block, and a first outer wall spaced apart from an upper portion of the inner wall with the upper buffer space therebetween; and a second outer wall spaced apart from the lower portion of the inner wall with the lower buffer space therebetween, the flange portion is connected to the first outer wall and the second outer wall, the upper buffer space communicates with the lower buffer space via the intermediate buffer space; The flange portion is an upper fastening plate through which the fastening member passes; a lower fastening plate through which the fastening member passes and which is spaced apart from the upper fastening plate with an internal space therebetween; a connecting plate connecting the upper fastening plate and the lower fastening plate, The battery pack according to claim 11 , wherein the internal space communicates with the intermediate buffer space.

13. The battery cell assembly a lower cover plate underlying the cell block; a top cover plate located over the top of the cell block and including cooling channels.

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

15. the side wall portion includes an upper wall extending between an upper end of the inner wall and an upper end of the first outer wall and coupled to the upper cover plate; a bottom wall extending between a lower end of the inner wall and a lower end of the second outer wall and coupled to the lower cover plate; 14. The battery pack of claim 13, further comprising:

16. The battery pack of 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 a sealed portion of the pouch-type battery cell inside the 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 and includes a vent.

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

20. 1. An electric mobility device including a battery pack, The battery pack includes a pack housing including a support structure; a battery cell assembly housed in the pack housing; The battery cell assembly includes a cell block including a plurality of battery cells; a side frame disposed on one side of the cell block, the side frame includes a side wall portion and a flange portion that is disposed on the side wall portion opposite the cell block and is fastened to the support structure; The sidewall portion includes an open space defined throughout the sidewall portion.

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