Battery pack and manufacturing method thereof

Abstract

The technical idea of ​​the present invention provides a battery pack including a pack housing and a battery assembly mounted in the pack housing, wherein the battery assembly includes a heat diffusion film attached to a bottom plate of the pack housing, a cell block including a plurality of battery cells stacked in a first direction, and a thermally conductive resin layer that attaches the cell block to the heat diffusion film.

Description

[Technical Field]

[0001] The present invention relates to a battery pack and a manufacturing method thereof.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0150503, filed November 3, 2023, and Korean Patent Application No. 10-2024-0145615, filed October 23, 2024, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0003] 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.

[0004] 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. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem that the present invention aims to achieve is to provide a battery pack and a manufacturing method thereof. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a battery pack including a pack housing and a battery assembly mounted in the pack housing, wherein the battery assembly includes a heat diffusion film attached to a bottom plate of the pack housing, a cell block including a plurality of battery cells, and a thermally conductive resin layer that attaches the cell block to the heat diffusion film.

[0007] In an exemplary embodiment, the bottom plate is characterized by including cooling channels configured to allow a cooling fluid to flow therethrough.

[0008] In an exemplary embodiment, the thermally conductive resin layer is in direct contact with the plurality of battery cells.

[0009] In an exemplary embodiment, the thermally conductive resin layer is not in contact with the bottom plate.

[0010] In an exemplary embodiment, the thermally conductive resin layer includes a thermosetting resin.

[0011] In an exemplary embodiment, the heat diffusion film further includes an adhesive layer configured to attach the heat diffusion film to the bottom plate, wherein the upper surface of the heat diffusion film is in contact with the thermally conductive resin layer and the lower surface of the heat diffusion film is in contact with the adhesive layer.

[0012] In an exemplary embodiment, the adhesive force between the heat spreading film and the bottom plate is smaller than the adhesive force between the heat spreading film and the cell block.

[0013] In an exemplary embodiment, the bottom plate is characterized by including a groove that accommodates the adhesive layer.

[0014] In an exemplary embodiment, the plurality of battery cells are arranged in a first direction, and the battery assembly further includes a fastening frame connected to one end of the cell block along the first direction and fastened to the pack housing.

[0015] In an exemplary embodiment, the device further includes a venting plate covering the cell block and including a venting portion configured to exhaust gas.

[0016] In an exemplary embodiment, the plurality of battery cells are arranged in a first direction, and each of the plurality of battery cells extends in a second direction perpendicular to the first direction, and the battery assembly further includes a bus bar electrically connected to at least one of the plurality of battery cells.

[0017] In an exemplary embodiment, the heat diffusion film includes a plurality of unit films, each of which provides a space for accommodating a corresponding one of the plurality of battery cells.

[0018] In an exemplary embodiment, the thermally conductive resin layer includes a first sub-thermal conductive resin layer configured to attach a first region of the cell block to the thermal diffusion film, and a second sub-thermal conductive resin layer configured to attach a second region of the cell block to the thermal diffusion film, wherein the thermal conductivity of the first sub-thermal conductive resin layer is greater than the thermal conductivity of the second sub-thermal conductive resin layer, and the adhesive strength of the first sub-thermal conductive resin layer is less than the adhesive strength of the second sub-thermal conductive resin layer.

[0019] In an exemplary embodiment, each of the plurality of battery cells includes a first outer casing, a second outer casing, and a central portion located between the first outer casing and the second outer casing, the first sub-thermal conductive resin layer is in contact with the first outer casing and the second outer casing of each of the plurality of battery cells, and the second sub-thermal conductive resin layer is in contact with the central portion of each of the plurality of battery cells.

[0020] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a method for manufacturing a battery pack, including the steps of applying a thermally conductive resin onto an upper surface of a thermal diffusion film, attaching a cell block including a plurality of battery cells to the upper surface of the thermal diffusion film to form a battery assembly including the cell block, the thermal diffusion film, and the thermally conductive resin, applying an adhesive layer onto a bottom plate of a pack housing, and attaching the thermal diffusion film to the bottom plate using the adhesive layer.

[0021] In an exemplary embodiment, the step of forming the battery assembly includes attaching the cell block onto the upper surface of the heat spreading film and applying heat to the thermally conductive resin to cure the thermally conductive resin.

[0022] In an exemplary embodiment, the heat diffusion film covers the lower surface of the cell block opposite the upper surface of the bottom plate, the thermally conductive resin is in direct contact with the plurality of battery cells and is not in contact with the bottom plate, the heat diffusion film is attached to the bottom plate by an adhesive layer locally applied to the upper surface of the bottom plate, and the adhesive force between the heat diffusion film and the bottom plate is smaller than the adhesive force between the heat diffusion film and the cell block.

[0023] In an exemplary embodiment, the method further includes the steps of separating the battery assembly from the bottom plate and attaching a new battery assembly to the bottom plate.

[0024] In an exemplary embodiment, in the cell block, the plurality of battery cells are arranged in a first direction, the battery assembly further includes a fastening frame provided at one end of the cell block along the first direction and fastened to the pack housing, and after the step of attaching the battery assembly to the bottom plate, the step of fastening the fastening frame to the pack housing using a fastening member is further included, and the step of separating the battery assembly from the bottom plate includes a step of releasing the fastening between the fastening frame and the pack housing. [Effects of the Invention]

[0025] According to an exemplary embodiment of the present invention, a battery assembly may have a cell-to-pack structure in which the battery cells are directly assembled to a pack housing of a battery pack. The battery cells are thermally coupled to a bottom plate of the pack housing, which has a cooling function, via a thermally conductive resin layer and a heat diffusion film, thereby effectively controlling heat generation in the battery cells and improving the safety and reliability of the battery pack.

[0026] According to an exemplary embodiment of the present invention, since the cell block is attached to the bottom plate via a heat diffusion film, the battery assembly corresponding to the cell-to-pack unit can be separated from the pack housing without damaging the battery cells. Since the cell-to-pack unit can be replaced in units of cells in the battery pack, costs can be reduced.

[0027] 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. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a perspective view of a battery assembly according to an exemplary embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a battery assembly according to an exemplary embodiment of the present invention. [Figure 3] 1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view showing the area indicated by "EX1" in FIG. [Figure 5a] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 5b] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 5c] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 5d] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 5e] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 5f] 1 is a diagram illustrating a method for manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 6a] 1A to 1C are cross-sectional views illustrating a method of manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 6b] 1A to 1C are cross-sectional views illustrating a method of manufacturing a battery pack according to an exemplary embodiment of the present invention. [Figure 7] 1 is a cross-sectional view of a battery assembly according to an exemplary embodiment of the present invention. [Figure 8] 1 is a cross-sectional view of a battery assembly according to an exemplary embodiment of the present invention. [Figure 9] 1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. [Figure 10]1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, it should be noted that the terms and words used in this 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 the inventor can appropriately define the concept of the term to best describe his / her invention.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] (First embodiment) Fig. 1 is a perspective view of a battery assembly 100 according to an exemplary embodiment of the present invention. Fig. 2 is a cross-sectional view of the battery assembly 100 according to an exemplary embodiment of the present invention.

[0034] Referring to FIGS. 1 and 2, the battery assembly 100 may include a cell block 110 , a heat diffusion film 121 , a thermally conductive resin layer 125 , a fastening frame 130 , and a venting plate 150 .

[0035] 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 cell case. The electrode assembly housed in the cell 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 rolled 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, 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.

[0036] The plurality of battery cells 111 may be connected in series and / or parallel. In one example, the plurality of battery cells 111 may be connected in series to each other. In one example, the plurality of battery cells 111 may be connected in parallel to each other. In one 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 may be connected in series to another bank consisting of two or more battery cells 111 connected in parallel to each other.

[0037] Each battery cell 111 can be a pouch-type battery cell, a cylindrical battery cell, or a prismatic battery cell. 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.

[0038] In an exemplary embodiment, the cell block 110 may include a plurality of battery cells 111 stacked on top of each other in a first horizontal direction (e.g., X direction). In the cell block 110, adjacent battery cells 111 among the plurality of battery cells 111 may be fixed to each other by an adhesive member such as adhesive tape. For example, the plurality of battery cells 111 may correspond to pouch-type battery cells whose length along the first horizontal direction (e.g., X direction) is shorter than their length along a second horizontal direction (e.g., Y direction). Each battery cell 111 may extend in the second horizontal direction (e.g., Y direction), and an electrode lead (see 1111 in FIG. 10 ) may be provided on at least one of both ends of each battery cell 111 along the second horizontal direction (e.g., Y direction).

[0039] The cell block 110 may include pads 113 attached to side surfaces of some of the battery cells 111 among the plurality of battery cells 111. The pads 113 may be attached to the corresponding battery cells 111 by an adhesive member such as an adhesive tape. The pads 113 may be disposed between adjacent battery cells 111 in a first horizontal direction (e.g., X direction) among the plurality of battery cells 111. The adjacent battery cells 111 may be spaced apart in the first horizontal direction (e.g., X direction) with the pads 113 interposed therebetween. The pads 113 may be disposed between the battery cells 111 and configured to support the battery cells 111. In an exemplary embodiment, the pads 113 may be configured to thermally isolate adjacent battery cells 111.

[0040] When viewed from above, the cell block 110 may have a rectangular shape. The cell block 110 may include an upper surface and a lower surface that are opposite in a vertical direction (e.g., Z direction), two side surfaces (i.e., a first side surface and a second side surface) that are opposite in a first horizontal direction (e.g., X direction), and a front surface and a rear surface that are opposite in a second horizontal direction (e.g., Y direction). The upper surface of the cell block 110 may include upper surfaces of the plurality of battery cells 111, and the lower surface of the cell block 110 may include lower surfaces of the plurality of battery cells 111.

[0041] A bus bar frame (see 143 in FIG. 10 ) supporting a bus bar 145 and electrode leads 1111 of the plurality of battery cells 111 may be disposed on each of the front and rear surfaces of the cell block 110. The bus bar frames 143 on the front and rear surfaces of the cell block 110 may each include a slit into which the electrode leads 1111 are inserted. Furthermore, the bus bar frames 143 on the front and rear surfaces of the cell block 110 may each support at least one bus bar 145 connected to at least one of the electrode leads 1111. Insulating covers 141 covering the bus bar frames 143 may be disposed on both ends of the battery assembly 100 in a second horizontal direction (e.g., the Y direction).

[0042] The bus bars 145 may be coupled to ends of corresponding battery cells 111 of the plurality of battery cells 111 along the second horizontal direction (e.g., the Y direction). The bus bars 145 may be electrically and physically coupled to at least one of the electrode leads 1111 of the plurality of battery cells 111. The bus bars 145 may be joined to at least one of the electrode leads 1111 of the plurality of battery cells 111 by welding. The bus bars 145 may include terminal bus bars for electrically coupling the cell blocks 110 of the battery assembly 100 to other cell blocks 110 of the battery assembly 100 or to an external electrical device. In an exemplary embodiment, the bus bars 145 may include inter-bus bars coupled to the electrode leads 1111 of different battery cells 111 to electrically couple the different battery cells 111 to each other.

[0043] A heat spreading film 121 may be attached to the underside of the cell block 110. The heat spreading film 121 may be configured to provide thermal coupling between the cell block 110 and a pack housing (501 in FIG. 5e) in which the battery assembly 100 is mounted.

[0044] The heat diffusion film 121 covers the lower surface of the cell block 110 and may have a generally uniform thickness. For example, the thickness of the heat diffusion film 121 may range from several to several hundred micrometers (μm). In exemplary embodiments, the thickness of the heat diffusion film 121 may be about 5 μm to about 30 μm, about 10 μm to about 25 μm, or about 15 μm to about 20 μm.

[0045] The heat spreading film 121 may have high thermal conductivity and be electrically non-conductive. In exemplary embodiments, the thermal conductivity of the heat spreading film 121 may be 500 W / (m·K) or more, 600 W / (m·K) or more, 700 W / (m·K) or more, 800 W / (m·K) or more, 900 W / (m·K) or more, 1000 W / (m·K) or more, 1100 W / (m·K) or more, 1200 W / (m·K) or more, 1300 W / (m·K) or more, 1400 W / (m·K) or more, 1500 W / (m·K) or more, 1600 W / (m·K) or more, 1700 W / (m·K) or more, 1800 W / (m·K) or more, 1900 W / (m·K) or more, or 2000 W / (m·K) or more. In exemplary embodiments, the thermal conductivity of the heat diffusion film 121 may be about 1500 W / (m·K) to about 2300 W / (m·K), about 1600 W / (m·K) to about 2200 W / (m·K), about 1700 W / (m·K) to about 2100 W / (m·K), or about 1800 W / (m·K) to about 2000 W / (m·K). The thermal conductivity of the heat diffusion film 121 may be greater than the thermal conductivity of the thermally conductive resin layer 125.

[0046] The thermally conductive resin layer 125 may be interposed between the thermal diffusion film 121 and the lower surface of the cell block 110 to attach the cell block 110 to the thermal diffusion film 121. The thermally conductive resin layer 125 may completely or partially fill the space between the thermal diffusion film 121 and the lower surface of the cell block 110. The thermally conductive resin layer 125 may thermally couple the thermal diffusion film 121 and the cell block 110. For example, the thermally conductive resin layer 125 may include a resin layer and a thermally conductive filler contained in the resin layer.

[0047] The thermally conductive resin layer 125 may be in contact with the lower surface of the cell block 110. The thermally conductive resin layer 125 may be in direct contact with the lower surfaces of the plurality of battery cells 111 and may extend along the lower surfaces of the plurality of battery cells 111.

[0048] In an exemplary embodiment, the thermally conductive resin layer 125 may include a thermosetting resin. In this case, the thermally conductive resin layer 125 may be formed by applying a thermosetting resin to the upper surface of the thermal diffusion film 121, attaching the cell block 110 to the thermal diffusion film 121, and applying heat to the thermosetting resin to harden it.

[0049] The fastening frame 130 may be attached to each of the battery cells 111 located at the outermost position in a first horizontal direction (e.g., the X direction) among the plurality of battery cells 111. The fastening frame 130 may be fastened to the pack housing 501 by fastening members 551 such as bolts. For example, the battery assembly 100 may be mounted on the pack housing 501 via the fastening frame 130 in a side-mounting manner.

[0050] The fastening frame 130 may include a first fastening frame 131 and a second fastening frame 135 spaced apart with the cell block 110 interposed therebetween. The first fastening frame 131 may be connected to one end of the cell block 110 along a first horizontal direction (e.g., the X direction), and the second fastening frame 135 may be connected to the other end of the cell block 110 along the first horizontal direction (e.g., the X direction). The first fastening frame 131 may include a first fixing plate 1311 attached to one end of the cell block 110 along the first horizontal direction (e.g., the X direction) using an adhesive member such as an adhesive tape, and a first flange 1313 fastened to the pack housing 501 using a fastening member 551. The first fixing plate 1311 has a flat plate shape covering one side of the cell block 110, and the first flange 1313 may be connected to a lower portion of the first fixing plate 1311. The second fastening frame 135 may include a second fixing plate 1351 attached to the other end of the cell block 110 along the first horizontal direction (e.g., X direction) via an adhesive member such as an adhesive tape, and a second flange 1353 fastened to the pack housing 501 via a fastening member 551. The second fixing plate 1351 has a flat plate shape covering one side of the cell block 110, and the second flange 1353 may be connected to an upper portion of the second fixing plate 1351.

[0051] The venting plate 150 may be provided on the cell block 110 and cover an upper surface of the cell block 110. The venting plate 150 may include a plurality of venting portions 1531 configured to exhaust gas. The venting plate 150 may include a support frame 151 including a plurality of openings 1511 and a cover sheet 153 attached to the support frame 151. The cover sheet 153 may cover an upper surface of the plurality of battery cells 111. The cover sheet 153 may include a heat-resistant sheet, a fire-resistant sheet, or a combination thereof. The cover sheet 153 may include venting portions 1531 configured to exhaust gas in each of areas corresponding to the plurality of openings 1511 of the support frame 151. The venting portions 1531 may correspond to incisions or incision lines formed in the cover sheet 153. High-temperature gas generated from the plurality of battery cells 111 may be exhausted to an external space above the battery assembly 100 through the plurality of venting portions 1531 of the cover sheet 153.

[0052] (Second embodiment) Fig. 3 is a cross-sectional view showing a battery pack 500 according to an exemplary embodiment of the present invention. Fig. 4 is an enlarged view showing the area indicated by "EX1" in Fig. 3.

[0053] 3 and 4 in conjunction with FIGS. 1 and 2, a battery pack 500 may include a pack housing (501 in FIG. 5e) and a battery assembly 100 mounted in the pack housing 501. The battery pack 500 may include one or more battery assemblies 100 mounted in the pack housing 501. In an exemplary embodiment, the multiple battery assemblies 100 may be accommodated in an accommodation space provided by the pack housing 501 and may be arranged in a first horizontal direction (e.g., X direction) and / or a second horizontal direction (e.g., Y direction) within the accommodation space of the pack housing 501.

[0054] The pack housing 501 may include a bottom plate 510 and a side wall (520 in FIG. 5e) coupled to an edge of the bottom plate 510. The side wall 520 may extend along the edge of the bottom plate 510 to surround the storage space of the pack housing 501. The pack housing 501 may further include a pack lid coupled to the side wall 520 of the pack housing 501 to cover the storage space. The storage space of the pack housing 501 may be a sealed space.

[0055] The bottom plate 510 may have a flat plate shape extending in a first horizontal direction (e.g., X direction) and a second horizontal direction (e.g., Y direction). The bottom plate 510 may support one or more battery assemblies 100.

[0056] The bottom plate 510 may include cooling channels 511 configured to allow a cooling fluid to flow therethrough and may be configured to cool the battery assembly 100. A cooling fluid provided from outside the battery pack 500 may be supplied to an inlet of the cooling channels 511, flow along the cooling channels 511, and be discharged to the outside through an outlet of the cooling channels 511. While the cooling fluid flows along the cooling channels 511, cooling may be provided to the plurality of battery cells 111 of the battery assembly 100. The cooling fluid may include a coolant and / or a refrigerant. In an exemplary embodiment, the bottom plate 510 may be formed by an extrusion process.

[0057] The battery assembly 100 may be attached to the bottom plate 510 by an adhesive layer 561 interposed between the lower surface of the heat diffusion film 121 and the upper surface of the bottom plate 510. For example, when assembling the battery assembly 100 to the pack housing 501, the adhesive layer 561 may be applied to the upper surface of the bottom plate 510, and then the battery assembly 100 may be attached to the upper surface of the bottom plate 510 using the adhesive layer 561. The adhesive layer 561 may allow the lower surface of the heat diffusion film 121 to be attached to the upper surface of the bottom plate 510. When the battery assembly 100 is attached to the bottom plate 510, the thermally conductive resin layer 125 may be spaced apart from the bottom plate 510 with the heat diffusion film 121 interposed therebetween and may not be in direct contact with the bottom plate 510. The adhesive layer 561 may include a resin layer and a heat-dissipating filler contained in the resin layer.

[0058] In an exemplary embodiment, the adhesive layer 561 may be applied locally to the upper surface of the bottom plate 510. In an exemplary embodiment, the adhesive layer 561 may be applied in spots to multiple regions on the upper surface of the bottom plate 510. In an exemplary embodiment, the total contact area between the adhesive layer 561 and the heat spreading film 121 may be smaller than the total contact area between the thermally conductive resin layer 125 and the heat spreading film 121. In an exemplary embodiment, the thickness of the adhesive layer 561 may be smaller than the thickness of the thermally conductive resin layer 125.

[0059] In an exemplary embodiment, the adhesive strength between the heat diffusion film 121 and the bottom plate 510 due to the adhesive layer 561 may be smaller than the adhesive strength between the heat diffusion film 121 and the cell block 110 due to the thermally conductive resin layer 125. The type of adhesive layer 561, the application area of ​​the adhesive layer 561, and the like can be adjusted so that the adhesive strength between the heat diffusion film 121 and the bottom plate 510 due to the adhesive layer 561 is smaller than the adhesive strength between the heat diffusion film 121 and the cell block 110 due to the thermally conductive resin layer 125. By configuring the adhesive strength between the heat diffusion film 121 and the bottom plate 510 due to the adhesive layer 561 to be smaller than the adhesive strength between the heat diffusion film 121 and the cell block 110 due to the thermally conductive resin layer 125, the heat diffusion film 121 can be easily removed from the pack housing 501 together with the cell block 110 when separating or disassembling the battery assembly 100 from the pack housing 501 for replacement of the battery assembly 100.

[0060] The battery assembly 100 may be fixed to the bottom plate 510 by fastening members 551 such as bolts. The first fastening frame 131 and the second fastening frame 135 of the battery assembly 100 may be fastened to the bottom plate 510 by fastening them to the bottom plate 510 by the fastening members 551. The fastening members 551 may be fastened to the bottom plate 510 so as not to interfere with the cooling channels 511 of the bottom plate 510.

[0061] In an exemplary embodiment, in the case of battery assemblies 100 adjacent in a first horizontal direction (e.g., the X direction), the second fastening frame 135 of one of the adjacent battery assemblies 100 may be fastened to the remaining first fastening frame 131 of the adjacent battery assemblies 100. More specifically, the second flange 1353 of the second fastening frame 135 of one of the adjacent battery assemblies 100 may rest on the first flange 1313 of the remaining first fastening frame 131 of the adjacent battery assemblies 100, and the second flange 1353 of the second fastening frame 135 may be fastened to the first flange 1313 of the first fastening frame 131 by fastening members 551. The adjacent battery assemblies 100 may be fastened to each other by fastening the second fastening frame 135 of one of the adjacent battery assemblies 100 to the remaining first fastening frame 131 of the adjacent battery assemblies 100.

[0062] (Third embodiment) 5a to 5f are diagrams illustrating a method for manufacturing a battery pack 500 according to an exemplary embodiment of the present invention. Hereinafter, a method for assembling the battery assembly 100 into the pack housing 501 will be described with reference to FIGS. 5a to 5f in conjunction with FIGS. 1 to 4.

[0063] Referring to FIG. 5a, a heat diffusion film 121 is prepared, and a heat conductive resin 125a is applied onto the heat diffusion film 121.

[0064] 5b and 5c, a structure 101 including a cell block 110 is prepared, and the structure 101 is attached to a heat diffusion film 121. The structure 101 may include the cell block 110, a first fastening frame 131, a second fastening frame 135, and a venting plate 150. The structure 101 may be temporarily bonded to the heat diffusion film 121 by a thermally conductive resin 125a.

[0065] 5d, heat 310 can be applied to the thermally conductive resin 125a to cure the thermally conductive resin 125a. As the thermally conductive resin 125a cures, the cell block 110 can be firmly attached to the thermal diffusion film 121. The thermally conductive resin 125a can be cured to form the thermally conductive resin layer 125. The cell block 110, the first fastening frame 131, the second fastening frame 135, the venting plate 150, the thermally conductive resin layer 125, and the thermal diffusion film 121 can constitute the battery assembly 100.

[0066] 5e, an adhesive layer 561 is applied to one mounting area on the upper surface of the bottom plate 510. The adhesive layer 561 can be applied locally to one mounting area on the upper surface of the bottom plate 510. Although FIG. 5e illustrates the adhesive layer 561 being applied to the bottom plate 510, in some exemplary embodiments, the adhesive layer 561 may be applied to the lower surface of the heat spreading film 121.

[0067] 5f, the battery assembly 100 is attached to one mounting area on the upper surface of the bottom plate 510. The battery assembly 100 may be attached to the bottom plate 510 by an adhesive layer 561 applied to the upper surface of the bottom plate 510.

[0068] Thereafter, an adhesive layer 561 can be applied to the remaining mounting areas on the top surface of the bottom plate 510, and a battery assembly 100 can be attached to each of the remaining mounting areas on the top surface of the bottom plate 510.

[0069] Next, the battery assemblies 100 can be fastened to the bottom plate 510 by fastening members 551. The first fastening frame 131 and the second fastening frame 135 of each battery assembly 100 can be fastened to the bottom plate 510 by the fastening members 551, respectively. In the case of battery assemblies 100 adjacent in a first horizontal direction (e.g., the X direction), the second fastening frame 135 of one of the adjacent battery assemblies 100 can be coupled to the remaining first fastening frame 131 of the adjacent battery assemblies 100 by the fastening members 551. The adjacent battery assemblies 100 can be coupled by fastening the second fastening frame 135 of one of the adjacent battery assemblies 100 to the remaining first fastening frame 131 of the adjacent battery assemblies 100.

[0070] 6a and 6b are cross-sectional views illustrating a method for manufacturing a battery pack 500 according to an exemplary embodiment of the present invention.

[0071] A method for replacing the battery assembly 100 in the battery pack 500 will be described below with reference to FIGS. 6a and 6b in addition to FIGS.

[0072] 6a, replacing the battery assembly 100 may include separating the defective battery assembly 100 from the pack housing 501. The step of separating the battery assembly 100 from the pack housing 501 may include releasing the fastening between the defective battery assembly 100 and the pack housing 501. To release the fastening between the defective battery assembly 100 and the bottom plate 510, the fastening members 551 may be separated from the first fastening frame 131 and the second fastening frame 135 of the battery assembly 100.

[0073] 6b, the step of separating the battery assembly 100 from the pack housing 501 may include lifting the battery assembly 100 upward so that the heat diffusion film 121 is separated from the bottom plate 510. For example, after a lifting mechanism is attached to the defective battery assembly 100, the defective battery assembly 100 may be lifted with the lifting mechanism to separate the defective battery assembly 100 from the pack housing 501.

[0074] In an exemplary embodiment, the adhesive strength between the heat spreading film 121 and the bottom plate 510 due to the adhesive layer 561 can be configured to be smaller than the adhesive strength between the heat spreading film 121 and the cell block 110 due to the thermally conductive resin layer 125. In this case, when the battery assembly 100 is lifted up to separate it from the bottom plate 510, the heat spreading film 121 can be easily separated from the bottom plate 510 together with the cell block 110.

[0075] After the defective battery assembly 100 is separated into the pack housing 501, a new battery assembly 100 can be assembled in one mounting area of ​​the bottom plate 510 that was exposed when the defective battery assembly 100 was removed. The new battery assembly 100 can be assembled into the pack housing 501 in substantially the same manner as the method for assembling the battery assembly 100 described with reference to Figures 5a to 5f.

[0076] According to an exemplary embodiment of the present invention, the battery assembly 100 may have a cell-to-pack structure in which the battery cells 111 are directly assembled to the pack housing 501 of the battery pack 500. The battery cells 111 are thermally coupled to the bottom plate 510 of the pack housing 501, which has a cooling function, via the thermally conductive resin layer 125 and the heat diffusion film 121 without an intermediate frame, so that heat generation of the battery cells 111 can be effectively controlled and the safety and reliability of the battery pack 500 can be improved.

[0077] In a typical battery pack, particularly in a battery pack in which a cell-to-pack unit including battery cells is fastened to a pack housing, the battery cells are directly attached to the pack housing by a resin layer. In this case, if the battery cells are separated from the pack housing, damage such as tearing may occur to the battery cells. Therefore, unit-by-unit replacement, in which the cell-to-pack unit is replaced with another cell-to-pack unit, is not possible, and only pack-by-pack replacement is possible.

[0078] According to an exemplary embodiment of the present invention, the cell block 110 is attached to the bottom plate 510 via the heat diffusion film 121, so that the battery assembly 100 corresponding to the cell-to-pack unit can be separated from the pack housing 501 without damaging the battery cells 111. The battery pack 500 allows replacement of the cell-to-pack unit, thereby reducing costs.

[0079] (Fourth embodiment) Fig. 7 is a cross-sectional view showing a battery assembly 100A according to an exemplary embodiment of the present invention. The battery assembly 100A shown in Fig. 7 will be described below, focusing on differences from the battery assembly 100 described with reference to Figs. 1 and 2.

[0080] 7 , in the battery assembly 100A, the heat diffusion film 121A may include a plurality of unit films 122. The plurality of unit films 122 may be separated from one another. The plurality of unit films 122 may be arranged in a first horizontal direction (e.g., the X direction). Each of the plurality of unit films 122 may overlap a corresponding one of the plurality of battery cells 111 in a vertical direction (e.g., the Z direction) and may be attached to the corresponding battery cell 111 by a thermally conductive resin layer 125. When separating or disassembling the battery assembly 100A from the pack housing 501, only some of the plurality of battery cells 111 may be removed. When replacing only the battery cell 111 that needs to be removed, the unit film 122 overlapping the battery cell 111 that needs to be removed may also be removed.

[0081] (Fifth embodiment) Fig. 8 is a cross-sectional view showing a battery assembly 100B according to an exemplary embodiment of the present invention. The battery assembly 100B shown in Fig. 8 will be described below, focusing on differences from the battery assembly 100 described with reference to Figs. 1 and 2.

[0082] Referring to FIG. 8 , in the battery assembly 100B, the heat diffusion film 121B may include a plurality of unit films 123. The plurality of unit films 123 may be separated from one another. The plurality of unit films 123 may be arranged in a first horizontal direction (e.g., the X direction). Two unit films 123 adjacent to one another in the first horizontal direction (e.g., the X direction) may contact one another. Each of the plurality of unit films 123 may accommodate a corresponding one of the plurality of battery cells 111. Each of the unit films 123 may have a folded shape to provide a space for accommodating a corresponding one of the plurality of battery cells 111. When viewed in cross section, each of the unit films 123 may have a U-shape. For example, each of the unit films 123 may include a bottom portion facing the bottom of the corresponding battery cell 111 and a pair of side cover portions spaced apart with the corresponding battery cell 111 interposed therebetween. One of the pair of side cover parts can contact one side of the corresponding battery cell 111, and the other of the pair of side cover parts can contact the other side of the corresponding battery cell 111.

[0083] (Sixth embodiment) Fig. 9 is a cross-sectional view showing a battery pack 500A according to an exemplary embodiment of the present invention. The following describes the battery pack 500A shown in Fig. 9, focusing on differences from the battery pack 500 described with reference to Figs. 3 and 4.

[0084] Referring to FIG. 9 , in the battery pack 500A, the bottom plate 510 may include a groove 519 that accommodates the adhesive layer 561. The groove 519 of the plate may limit the application area of ​​the adhesive layer 561. The groove 519 of the bottom plate 510 may be rectangular or circular when viewed from above. The adhesive layer 561 may completely or partially fill the groove 519 of the bottom plate 510. A portion of the adhesive layer 561 may overflow from the groove 519 of the bottom plate 510 and be applied to the surface of the bottom plate 510 around the groove 519 of the bottom plate 510. The bottom plate 510 may include a plurality of grooves 519 spaced apart from one another, and the adhesive layer 561 may be provided inside each of the plurality of grooves 519 of the bottom plate 510.

[0085] (Seventh embodiment) Fig. 10 is a cross-sectional view showing a battery pack 500B according to an exemplary embodiment of the present invention. The following describes the battery pack 500B shown in Fig. 10, focusing on differences from the battery pack 500 described with reference to Figs. 3 and 4.

[0086] 10 , in the battery pack 500B, the thermally conductive resin layer 125A may include multiple sub-thermally conductive resin layers having different material compositions, thermal conductivities, and / or adhesive strengths. The multiple sub-thermally conductive resin layers of the thermally conductive resin layer 125A may be attached to different regions of the cell block 110. The multiple sub-thermally conductive resin layers may include a thermally conductive filler, and the content of the thermally conductive filler in the multiple sub-thermally conductive resin layers may differ from one another. The thermally conductive filler may include, for example, alumina, boron nitride, aluminum nitride, zinc oxide, magnesium oxide, or a combination thereof.

[0087] In the exemplary embodiment, the thermally conductive resin layer 125A may include a first sub-thermal conductive resin layer 1251 in contact with a first region of the cell block 110 and a second sub-thermal conductive resin layer 1253 in contact with a second region of the cell block 110. The first sub-thermal conductive resin layer 1251 may attach the first region of the cell block 110 to the thermal diffusion film 121, and the second sub-thermal conductive resin layer 1253 may attach the second region of the cell block 110 to the thermal diffusion film 121. The first sub-thermal conductive resin layer 1251 may attach a portion of the plurality of battery cells 111 in the first region of the cell block 110 to the thermal diffusion film 121, and the second sub-thermal conductive resin layer 1253 may attach a portion of the plurality of battery cells 111 in the second region of the cell block 110 to the thermal diffusion film 121.

[0088] The first sub-thermal conductive resin layer 1251 may have a first thermal conductivity and a first adhesive strength, and the second sub-thermal conductive resin layer 1253 may have a second thermal conductivity and a second adhesive strength. The first thermal conductivity of the first sub-thermal conductive resin layer 1251 may be greater than the second thermal conductivity of the second sub-thermal conductive resin layer 1253. The first adhesive strength of the first sub-thermal conductive resin layer 1251 may be less than the second adhesive strength of the second sub-thermal conductive resin layer 1253. The first sub-thermal conductive resin layer 1251, which has a relatively high thermal conductivity, may be attached to a portion of the cell block 110 where a relatively large amount of heat is generated, thereby enhancing cooling of the cell block 110. The second sub-thermal conductive resin layer 1253, which has a relatively low thermal conductivity, may be attached to a portion of the cell block 110 where a relatively small amount of heat is generated. The first sub-thermal conductive resin layer 1251 is attached to a portion of the cell block 110 where a relatively large amount of heat is generated, and the second sub-thermal conductive resin layer 1253 is attached to a portion of the cell block 110 where a relatively small amount of heat is generated, thereby reducing temperature deviation within the cell block 110. The second sub-thermal conductive resin layer 1253, which has a relatively high adhesive strength, is attached to a portion of the cell block 110 that is relatively vulnerable to vibration, thereby enhancing the structural stability of the cell block 110.

[0089] In exemplary embodiments, the first thermal conductivity of the first sub-thermal conductive resin layer 1251 may be approximately 3 W / (m·K) to 10 W / (m·K), approximately 4 W / (m·K) to 9 W / (m·K), approximately 5 W / (m·K) to 8 W / (m·K), or approximately 6 W / (m·K) to 7 W / (m·K). In exemplary embodiments, the second thermal conductivity of the second sub-thermal conductive resin layer 1253 may be approximately 20% to 80%, approximately 30% to 70%, or approximately 40% to 60% of the first thermal conductivity of the first sub-thermal conductive resin layer 1251.

[0090] In an exemplary embodiment, the second adhesive strength of the second sub-thermal conductive resin layer 1253 may be about 1 MPa to about 5 MPa, about 1.5 MPa to about 4.5 MPa, about 2 MPa to about 4 MPa, or about 2.5 MPa to about 3.5 MPa. In an exemplary embodiment, the first adhesive strength of the first sub-thermal conductive resin layer 1251 may be about 10% to about 90%, about 20% to about 80%, about 30% to about 70%, or about 40% to about 60% of the second adhesive strength of the second sub-thermal conductive resin layer 1253.

[0091] In the exemplary embodiment, the plurality of battery cells 111 may each include a first portion relatively adjacent to the electrode lead 1111 and a second portion relatively distant from the electrode lead 1111. The first portion of the plurality of battery cells 111 may be within a first region of the cell block 110, and the second portion of the plurality of battery cells 111 may be within a second region of the cell block 110. The first sub-thermal conductive resin layer 1251 may be in contact with the first portion of the plurality of battery cells 111, and the second sub-thermal conductive resin layer 1253 may be in contact with the second portion of the plurality of battery cells 111. The first portion of the battery cell 111 relatively adjacent to the electrode lead 1111 is a portion where a relatively large amount of heat is generated during operation of the battery cell 111, and the second portion of the battery cell 111 relatively distant from the electrode lead 1111 is a portion where a relatively small amount of heat is generated during operation of the battery cell 111. The first sub-thermal conductive resin layer 1251, which has a relatively high thermal conductivity, is attached to a first portion of each of the plurality of battery cells 111, thereby enhancing cooling for the plurality of battery cells 111. The second sub-thermal conductive resin layer 1253, which has a relatively low thermal conductivity, is attached to a second portion of each of the plurality of battery cells 111. By attaching the first sub-thermal conductive resin layer 1251 to the first portion of each of the plurality of battery cells 111 and the second sub-thermal conductive resin layer 1253 to the second portion of each of the plurality of battery cells 111, temperature deviation in each of the plurality of battery cells 111 can be reduced. In each battery cell 111, the first portion of the battery cell 111 is supported by the bus bar frame 143 and the insulating cover 141 and has relatively high structural stability, while the second portion of the battery cell 111 is relatively distant from the bus bar frame 143 and the insulating cover 141 and has relatively low structural stability. The second sub-thermal conductive resin layer 1253 having a relatively high adhesive strength can attach the second portion of each of the plurality of battery cells 111 to the heat diffusion film 121 and enhance the structural stability of the plurality of battery cells 111.

[0092] In an exemplary embodiment, each of the plurality of battery cells 111 may include a first outer portion connected to an electrode lead 1111, a second outer portion connected to another electrode lead 1111, and a central portion located between the first outer portion and the second outer portion. The battery cells 111 may extend in a second horizontal direction (e.g., the Y-axis direction), and the central portion of the battery cell 111 may be between the first outer portion of the battery cell 111 and the second outer portion of the battery cell 111 in the second horizontal direction (e.g., the Y-axis direction). The first outer portion and the second outer portion of each battery cell 111 may be within a first region of the cell block 110, and the central portion of each battery cell 111 may be within a second region of the cell block 110.

[0093] The first sub-thermal conductive resin layer 1251 may be in contact with a first outer portion and a second outer portion of each battery cell 111, and the second sub-thermal conductive resin layer 1253 may be in contact with a center portion of each battery cell 111. The first outer portion and the second outer portion of the battery cell 111 are respectively relatively close to the electrode leads 1111 and generate a relatively large amount of heat during operation of the battery cell 111, while the center portion of the battery cell 111 is relatively far from the electrode leads 1111 and generates a relatively small amount of heat during operation of the battery cell 111. The first sub-thermal conductive resin layer 1251, which has a relatively high thermal conductivity, may be attached to the first outer portion and the second outer portion of each of the plurality of battery cells 111, thereby enhancing cooling of the plurality of battery cells 111. The second sub-thermal conductive resin layer 1253, which has a relatively low thermal conductivity, may be attached to the center portion of each of the plurality of battery cells 111. The first sub-thermal conductive resin layer 1251 is attached to the first outer periphery and the second outer periphery of each of the plurality of battery cells 111, and the second sub-thermal conductive resin layer 1253 is attached to the center of each of the plurality of battery cells 111, thereby reducing the temperature deviation in each of the plurality of battery cells 111. The temperature deviation between regions of the battery cells 111 can be more effectively controlled by adjusting the size of the center of the battery cell 111 in contact with the second sub-thermal conductive resin layer 1253. For example, the length of the center of the battery cell 111 in contact with the second sub-thermal conductive resin layer 1253 along the second horizontal direction (e.g., the Y-axis direction) may be about 10% to about 70%, about 20% to about 60%, or about 30% to about 50% of the length of the battery cell 111 along the second horizontal direction (e.g., the Y-axis direction).

[0094] The first and second outer portions of the battery cells 111 are supported by the bus bar frame 143 and the insulating cover 141, respectively, and have relatively high structural stability, while the center portions of the battery cells 111 are relatively far from the bus bar frame 143 and the insulating cover 141, and have relatively low structural stability. The second sub-thermal conductive resin layer 1253, which has relatively high adhesive strength, attaches the center portions of the plurality of battery cells 111 to the heat diffusion film 121, thereby enhancing the structural stability of the plurality of battery cells 111.

[0095] According to the battery pack 500B according to the exemplary embodiment, a portion of each battery cell 111 that generates a relatively large amount of heat can be attached to the heat diffusion film 121 with a thermally conductive resin layer having a relatively high thermal conductivity, and a portion of each battery cell 111 that is relatively vulnerable to vibration can be attached to the heat diffusion film 121 with a thermally conductive resin layer having a relatively high adhesive strength. Therefore, compared to the case where the battery cell 111 is attached to the heat diffusion film 121 with a single adhesive layer, it is possible to improve the temperature uniformity of the battery cell 111 and strengthen the structural safety of the battery cell 111.

[0096] The present invention has been described in more detail above with reference to 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]

[0097] 100, 100A, 100B Battery Assembly 101 Structure 110 Cell Block 111 Battery Cell 113 Pad 121, 121A, 121B Heat diffusion film 122, 123 unit film 125, 125A Thermally conductive resin layer 125a Thermally conductive resin 130 Fastening Frame 131 First fastening frame 135 Second fastening frame 141 Insulating cover 143 Busbar Frame 145 Busbar 150 Venting Plate 151 Support Frame 153 Cover Sheet 310 fever 500, 500A, 500B Battery Pack 501 Pack Housing 510 bottom plate 511 Cooling Channel 519 Groove 520 side wall 551 Fastening members 561 Adhesive layer 1111 Electrode lead 1251 First sub-thermal conductive resin layer 1253 Second sub-thermal conductive resin layer 1311 1st fixed plate 1313 First flange 1351 2nd fixed plate 1353 Second flange 1511 Opening 1531 Venting Department

Claims

1. A pack housing; a battery assembly mounted in the pack housing; Including, The battery assembly includes: a heat diffusion film attached to the bottom plate of the pack housing; a cell block including a plurality of battery cells; a thermally conductive resin layer that attaches the cell block to the thermal diffusion film; Including the battery pack.

2. The battery pack of claim 1 , wherein the bottom plate includes a cooling channel configured to allow a cooling fluid to flow therethrough.

3. The battery pack according to claim 1 , wherein the thermally conductive resin layer is in direct contact with the plurality of battery cells.

4. The battery pack according to claim 3 , wherein the thermally conductive resin layer is not in contact with the bottom plate.

5. The battery pack according to claim 1 , wherein the thermally conductive resin layer includes a thermosetting resin.

6. 2. The battery pack of claim 1, further comprising an adhesive layer configured to attach the heat spreading film to the bottom plate, wherein an upper surface of the heat spreading film is in contact with the thermally conductive resin layer and a lower surface of the heat spreading film is in contact with the adhesive layer.

7. The battery pack according to claim 6 , wherein an adhesive force between the heat diffusion film and the bottom plate is smaller than an adhesive force between the heat diffusion film and the cell block.

8. The battery pack of claim 6 , wherein the bottom plate includes a groove that accommodates the adhesive layer.

9. The plurality of battery cells are arranged in a first direction, The battery pack of claim 1 , wherein the battery assembly further comprises a fastening frame connected to one end of the cell block along the first direction and fastened to the pack housing.

10. The battery pack of claim 1 , further comprising a venting plate covering the cell block and including a venting portion configured to exhaust gas.

11. The plurality of battery cells are arranged in a first direction, The plurality of battery cells each extend in a second direction perpendicular to the first direction, The battery pack of claim 1 , wherein the battery assembly further comprises a bus bar electrically coupled to at least one of the plurality of battery cells.

12. The heat diffusion film includes a plurality of unit films, The battery pack according to claim 1 , wherein each of the plurality of unit films of the heat diffusion film provides a space for accommodating a corresponding one of the plurality of battery cells.

13. The thermally conductive resin layer is a first sub-thermal conductive resin layer configured to attach a first region of the cell block to the thermal diffusion film; a second sub-thermal conductive resin layer configured to attach a second region of the cell block to the thermal diffusion film; Including, the thermal conductivity of the first sub-thermal conductive resin layer is greater than the thermal conductivity of the second sub-thermal conductive resin layer; The battery pack according to claim 1 , wherein an adhesive strength of the first sub-thermal conductive resin layer is smaller than an adhesive strength of the second sub-thermal conductive resin layer.

14. Each of the plurality of battery cells includes a first outer portion, a second outer portion, and a center portion located between the first outer portion and the second outer portion; the first sub-thermal conductive resin layer is in contact with the first outer portion and the second outer portion of each of the plurality of battery cells; The battery pack according to claim 13 , wherein the second sub-thermal conductive resin layer is in contact with the center portion of each of the plurality of battery cells.

15. Applying a thermally conductive resin on the upper surface of the heat diffusion film; attaching a cell block including a plurality of battery cells to the upper surface of the heat spreading film to form a battery assembly including the cell block, the heat spreading film, and the thermally conductive resin; applying an adhesive layer onto a bottom plate of the pack housing; attaching the heat spreading film to the bottom plate using the adhesive layer; A method for manufacturing a battery pack, comprising:

16. 16. The method of manufacturing a battery pack according to claim 15, wherein the step of forming the battery assembly includes attaching the cell block onto the upper surface of the heat spreading film, and applying heat to the thermally conductive resin to harden the thermally conductive resin.

17. the heat diffusion film covers a lower surface of the cell block opposite to an upper surface of the bottom plate; the thermally conductive resin is in direct contact with the battery cells and is not in contact with the bottom plate; the heat diffusion film is attached to the bottom plate by an adhesive layer locally applied to the top surface of the bottom plate; The method for manufacturing a battery pack according to claim 16 , wherein an adhesive force between the heat diffusion film and the bottom plate is smaller than an adhesive force between the heat diffusion film and the cell block.

18. separating the battery assembly from the bottom plate; attaching a new battery assembly to the bottom plate; The method for manufacturing a battery pack of claim 15 further comprising:

19. In the cell block, the plurality of battery cells are arranged in a first direction, the battery assembly further includes a fastening frame provided at one end of the cell block along the first direction and fastened to the pack housing; The method further includes the step of fastening the fastening frame to the pack housing using fastening members after the step of attaching the battery assembly to the bottom plate; The method of manufacturing a battery pack according to claim 18 , wherein separating the battery assembly from the bottom plate includes releasing a fastening between the fastening frame and the pack housing.

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