Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell assembly in which a plurality of battery cells are stacked, a first sub-module and a second sub-module, each of which includes a bus bar that electrically connects the battery cells and a bus bar frame that covers at least one side of the battery cell assembly, a module housing that simultaneously houses the first sub-module and the second sub-module, and a terminal assembly located in a portion overlapping a region between the first sub-module and the second sub-module, wherein an opening is formed in a portion of the module housing that overlaps the module extension, and the terminal assembly is connected to the terminal bus bars of the first sub-module and the second sub-module through the opening.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0181906 dated December 22, 2022 and Korean Patent Application No. 10-2023-0185439 dated December 19, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module having a cooling structure that utilizes insulating oil and a battery pack including the same. [Background technology]

[0003] With technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting attention as an energy source not only for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0004] While small mobile devices use one or two to three battery cells per device, medium to large devices such as automobiles require high output and large capacity, so medium to large battery modules, which electrically connect multiple battery cells, are used.

[0005] Meanwhile, when connecting multiple battery cells in series / parallel to form a battery module and / or a battery pack, a common method is to form a battery module consisting of at least one battery cell, and then use the at least one battery module to add other components to form a battery pack.

[0006] The battery cells that make up these medium- and large-sized battery modules are made up of rechargeable secondary batteries, and these high-power, large-capacity secondary batteries generate a large amount of heat during the charging and discharging process. In this case, the heat generated from the multiple battery cells can be combined in a small space, causing a sudden rise in temperature. In other words, battery modules with multiple stacked battery cells and battery packs equipped with these battery modules can produce high power output, but it is not easy to remove the heat generated from the battery cells during charging and discharging. If the heat from the battery cells is not properly dissipated, the battery cells will deteriorate faster, their lifespan will be shortened, and the risk of explosion or fire will increase.

[0007] Furthermore, battery modules included in vehicle battery packs are frequently exposed to direct sunlight and may be placed in high-temperature conditions such as summer or desert regions. Also, because multiple battery modules are concentrated in one location to increase the vehicle's driving range, flames or heat generated in one battery module can easily spread to adjacent battery modules, ultimately leading to fire or explosion of the battery pack itself.

[0008] FIG. 1 is a diagram showing a heat dissipation path in a conventional battery module.

[0009] 1, a conventional battery module 30 includes a cell assembly 70 including battery cells 60 stacked in a predetermined direction, and a module frame 40 that houses the cell assembly 70, with the cell assembly 70 being fixed onto a thermally conductive resin layer 50 located on the underside of the module frame 40. In this case, to cool heat generated in the cell assembly 70, a heat sink 90 is provided facing the bottom of the module frame 40 located in the -z-axis direction of FIG. 1, and a thermally conductive pad 80 for heat transfer may be further installed between the heat sink 90 and the bottom of the module frame 40.

[0010] However, since the heat sink 90 does not directly contact the cell assembly 70 to transfer heat, the cooling efficiency is not very high, and the cooling path is formed in one direction (-z axis direction) of the width direction of the battery cell, which may cause a temperature gradient.

[0011] Therefore, in order to extend the life of the battery module and / or battery pack, it is necessary to improve the cooling efficiency of the battery module / battery pack so that the temperature of the battery cells does not become too high. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a battery module and a battery pack including the same that maximize cooling performance by directly cooling battery cells.

[0013] In addition, the present invention aims to provide a battery module and a battery pack including the same that maximize energy density by integrating the structures of the battery module and the battery pack and by using a highly rigid housing to ensure sealing reliability.

[0014] The problems to be solved by the present invention are not limited to those described above, and problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0015] A battery module according to one embodiment of the present invention includes a battery cell assembly in which a plurality of battery cells are stacked, a first sub-module and a second sub-module, each of which includes a bus bar that electrically connects the battery cells and a bus bar frame that covers at least one side of the battery cell assembly, a module housing that simultaneously houses the first sub-module and the second sub-module, and a terminal assembly located in a portion overlapping a region between the first sub-module and the second sub-module, wherein an opening is formed in a portion of the module housing that overlaps the module extension, and the terminal assembly is connected to the terminal bus bars of the first sub-module and the second sub-module through the opening.

[0016] The battery module may further include a bracket positioned in the opening, and a sealing member formed between the bracket and the terminal assembly.

[0017] The terminal assembly may include a flexible connecting cable, a terminal housing coupled to the connecting cable, and an upper cap connected to the bracket and covering an upper portion of the terminal housing.

[0018] The module housing is formed of a highly rigid material, and the highly rigid material may include a composite material such as fiber reinforced plastic (FRP).

[0019] The battery module may further include a flange portion formed on a side surface of the module housing, and a module fastening member coupled to the flange portion.

[0020] A battery pack according to another embodiment of the present invention includes a plurality of battery modules, wherein a first battery module and a second battery module included in the plurality of battery modules are adjacent to each other, the first battery module and the second battery module are electrically connected by a first terminal assembly and a second terminal assembly, and the first terminal assembly and the second terminal assembly are connected by a fixing member.

[0021] The first battery module and the second battery module may have flange portions that overlap each other, and the first battery module and the second battery module may be coupled to each other by a module fastening member that penetrates the overlapping flange portions.

[0022] The coupling portion including the module fastening member may form a rigid beam of the battery pack.

[0023] The fixing member can be fastened to the module housing by a fastening member.

[0024] The battery pack may further include a pack frame that encases the plurality of battery modules on the front, rear, left, and right sides, respectively, and the pack frame may separate the plurality of battery modules into a plurality of parts corresponding to the front, rear, left, and right sides, respectively.

[0025] The battery pack may further include a frame fastening portion formed on a side surface of the module housing, and at least one of the pack frames may be connected to the battery module by inserting a frame fastening member into the frame fastening portion.

[0026] At least one of the pack frames may have a mounting hole formed therein, the mounting hole being arranged to correspond to a hole formed in a mounting portion of an end plate of the battery module, and the frame fastening member may be inserted into the mounting hole and the hole formed in the mounting portion.

[0027] The overall structure of the pack frame may have a shape that exposes the upper and lower portions of the battery module.

[0028] The upper and lower portions of the module housing, formed from a highly rigid material, can form the upper and lower covers of the pack frame.

[0029] The first terminal assembly and the second terminal assembly may be connected to terminal bus bars having different polarities. [Effects of the Invention]

[0030] According to the embodiment, the cooling performance of the battery module can be maximized by circulating insulating oil to directly cool the battery cells.

[0031] Furthermore, the use of a highly rigid housing ensures sealing reliability.

[0032] In addition, energy density can be maximized by integrating the battery module and battery pack structures.

[0033] The effects of the present invention are not limited to those described above, and effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a diagram showing a heat dissipation path in a conventional battery module. [Figure 2] 1 is a perspective view showing a battery module according to an embodiment of the present invention; [Figure 3] FIG. 3 is an exploded perspective view of the battery module of FIG. 2. [Figure 4] 3 is a perspective view showing a state in which a terminal assembly is connected to the battery module of FIG. 2. FIG. [Figure 5] 5 is a diagram showing a terminal assembly included in the battery module of FIG. 4. [Figure 6] FIG. 5 is an exploded perspective view showing a cell assembly included in the battery module of FIG. 4. [Figure 7] FIG. 7 is a perspective view showing the cell assembly of FIG. 6 before a bus bar frame is joined to the cell assembly. [Figure 8] FIG. 2 is a perspective view showing the connection of a busbar bolt and a nut according to an embodiment of the present invention. [Figure 9] 5 is a perspective view showing a battery pack formed by connecting a plurality of battery modules of FIG. 4. FIG. [Figure 10] 1 is a front view of adjacent battery modules coupled together. [Figure 11] 1 is a perspective view showing a combination of a battery module and a cooling assembly according to a first embodiment of the present invention; [Figure 12] 2 is a view showing the front or rear of a battery module according to an embodiment of the present invention; [Figure 13] 1 is a front view showing the coupling of a cooling assembly in a battery pack according to an embodiment of the present invention; [Figure 14] 1 is a front view showing the coupling of a cooling assembly in a battery pack according to an embodiment of the present invention; [Figure 15] FIG. 10 is a schematic diagram showing the connection relationship of a cooling assembly in a battery pack according to a comparative example. [Figure 16] 2 is a schematic diagram showing the connection relationship of a cooling assembly in a battery pack according to an embodiment of the present invention. [Figure 17] 1 is a view showing a combination of a battery module and a pack frame according to an embodiment of the present invention; [Figure 18] 1 is a view showing a combination of a battery module and a pack frame according to an embodiment of the present invention; [Figure 19] 1 is a plan view showing a structure in which a terminal assembly is connected in a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement various embodiments of the present invention. The present invention can be embodied in several different forms and is not limited to the examples described herein.

[0036] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0037] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0038] Furthermore, throughout this specification, when a part "comprises" a certain component, it does not mean that it excludes other components, but that it may further include other components, unless otherwise specified.

[0039] Also, throughout the specification, "on a plane" means when the target part is viewed from above, and "on a cross section" means when the target part is cut vertically and viewed from the side.

[0040] Fig. 2 is a perspective view showing a battery module according to an embodiment of the present invention. Fig. 3 is an exploded perspective view of the battery module of Fig. 2. Fig. 4 is a perspective view showing a state in which a terminal assembly is connected to the battery module of Fig. 2. Fig. 5 is a view showing a terminal assembly included in the battery module of Fig. 4. Fig. 6 is an exploded perspective view showing a cell assembly included in the battery module of Fig. 4. Fig. 7 is a perspective view showing a state before a bus bar frame is coupled to the cell assembly of Fig. 6.

[0041] 2, 3, 6, and 7, the battery module 100 according to this embodiment includes a cell assembly 120 in which a plurality of battery cells 110 are stacked, a first sub-module 100a, and a second sub-module 100b, each of which includes a bus bar frame 130 including bus bars that electrically connect the battery cells 110 and a bus bar frame that covers at least one side of the cell assembly 120, and a module housing 200 that simultaneously houses the first sub-module 100a and the second sub-module 100b.

[0042] The battery cells provided in the cell assembly 120 may be pouch-shaped, which maximizes the number of cells stacked per unit area. Pouch-shaped battery cells can be manufactured by placing an electrode assembly including a positive electrode, a negative electrode, and a separator in a cell case made of a laminate sheet and then heat-sealing the sealing portion of the cell case. However, battery cells do not necessarily have to be provided in pouch shape, and can also be provided in various shapes such as prismatic, cylindrical, or other shapes as long as the storage capacity required by the device to be installed in the future is achieved.

[0043] Meanwhile, a pouch-type battery cell may have a length, width, and thickness, and the length, width, and thickness directions of the battery cell may be perpendicular to each other. For example, as shown in Figures 2, 6, and 7, the length direction of the battery cell can be described as the y-axis direction, the width direction as the z-axis direction, and the thickness direction as the x-axis direction. Accordingly, the length direction of the cell assembly 120 can be described as the y-axis direction, and the direction in which the battery cells are stacked in the cell assembly 120 (hereinafter referred to as the stacking direction) can be described as the x-axis direction.

[0044] 6, cooling fins 210 are disposed between adjacent battery cells 110, and the cooling fins 210 can be cooled by receiving heat generated from the battery cells 110 and coming into contact with insulating oil. In addition, an insulating plate 115 can be formed on the outermost periphery of the cell assembly 120.

[0045] 7, each battery cell of the cell assembly 120 may include electrode leads protruding on both sides in the length direction (y-axis direction). One end of the electrode lead is located inside the battery cell and electrically connected to the positive or negative electrode of the electrode assembly inside the battery cell, and the other end of the electrode lead protrudes outside the battery cell and electrically connected to a bus bar attached to the bus bar frame 130.

[0046] The bus bar frame 130 may be positioned on one side of the cell assembly 120 to cover that side and also to guide the connection of the cell assembly 120 to an external device. The bus bar frame 130 may be coupled to the front or rear side of the cell assembly 120 with the outermost corner of the cell assembly 120 being pressed by the insulating plate 115. The bus bar frame 130 may be provided on each of the front and rear sides of the cell assembly 120. Here, the front or rear side may be the side on which the electrode leads of each battery cell of the cell assembly 120 are located.

[0047] The bus bar frame 130 may include slits 131 into which electrode leads of the battery cells can be inserted. The electrode leads that pass through the slits 131 can be connected to bus bars 132 attached to one side of the bus bar frame 130. The electrode leads of each battery cell are connected to the bus bars 132, thereby electrically connecting the multiple battery cells of the cell assembly 120. The slits 131 can also function as a passage through which a refrigerant flows into the battery module 100. In this embodiment, the refrigerant is injected through the end plates 400, and the injected refrigerant can pass through the slits 131 of the bus bar frame 130 to come into contact with the battery cells. The refrigerant that has come into contact with the battery cells can also be discharged to the outside of the battery module 100 through the slits 131.

[0048] The bus bar frame 130 can be made of an electrically insulating material. By including an insulating material in the bus bar frame 130, it is possible to limit contact between the bus bars 132 and other parts of the battery cell other than the electrode leads, thereby preventing the occurrence of an electrical short circuit.

[0049] The bus bar frame 130 may be fitted with terminal bus bars 133, 134 that provide electrical connection between the cell assembly 120 and an external device. The terminal bus bars 133, 134 are high-potential terminals and may be connected to an HV connection assembly 500 (see FIG. 19 ) that electrically connects two battery modules 100. Here, the terminal bus bars 133, 134 may include a first terminal bus bar 133 and a second terminal bus bar 134, each of which may have a different polarity.

[0050] FIG. 8 is a perspective view showing the connection of a busbar bolt and a nut according to one embodiment of the present invention.

[0051] Referring to FIG. 8 , the first terminal bus bar 133 may be connected to a bus bar bolt 138 and a bus bar nut 139. As described below, the bus bar bolt 138 and the bus bar nut 139 may facilitate connection between the first terminal bus bar 133 and the terminal assembly 300. The first terminal bus bar 133 is disposed such that one end thereof protrudes along the length direction of the battery cell, and the protruding end may have a surface parallel to the ground (xy plane). Holes into which the bus bar bolts 138 can be inserted are formed in the one surface of the first terminal bus bar 133, and the bus bar bolts 138 passing through the holes on one side of the first terminal bus bar 133 may be coupled to the bus bar nut 139 on the other side. Here, although the drawings show the bus bar bolts 138 being inserted from top to bottom, this is not necessarily the case; the bus bar bolts 138 may also be inserted from bottom to top in this embodiment.

[0052] Meanwhile, although the above description has focused on the first terminal bus bar 133, the above description can also be applied to the second terminal bus bar 134. For example, the second terminal bus bar 134 attached to the bus bar frame 130 may have one surface parallel to the ground. In addition, the second terminal bus bar 134 may be provided with bus bar bolts 138 passing through holes formed in the one surface and bus bar nuts 139 coupled to the bus bar bolts 138.

[0053] 8, a sensing unit 140 may be located on one side of the bus bar frame 130. The sensing unit 140 is for a low voltage (LV) connection, where LV connection may refer to a sensing connection for sensing and controlling the voltage of a battery cell. The sensing unit 140 may include a sensing terminal for sensing the voltage value of the bus bar 132, a temperature sensor for sensing the temperature inside the battery module 100, and a connection member for connecting these. For example, the sensing unit 140 may include a printed circuit board (PCB) and / or a flexible flat cable (FFC). Alternatively, the sensing unit 140 may include a flexible printed circuit board (FPCB).

[0054] 2, the module housing 200 according to this embodiment may be configured to protect the cell assembly 120 and the electrical components connected thereto from external physical impacts. The module housing 200 may accommodate the cell assembly 120 and the electrical components connected thereto in an internal space.

[0055] The module housing 200 may be provided in various structures. For example, the module housing 200 may be in the form of a metal plate with an integrated top, bottom, and both side surfaces. Here, the module housing may be manufactured by extrusion molding. However, instead, the module housing 200 may be provided in the form of a U-shaped frame and plate in which one of the top and bottom surfaces is connected to both side surfaces, or in the form of two L-shaped frames in which one of the top and bottom surfaces is connected to one side surface. In this case, each frame or plate may be manufactured by press molding.

[0056] The components of the module housing 200 may be joined by welding or the like with corresponding corners in contact with each other, or may be fixed using a separate fastening member. In addition, the components of the module housing 200 may be made of a metal material having a predetermined strength.

[0057] The module housing 200 may be provided in an open shape along the length (y-axis direction) of the cell assembly 120, and after accommodating the cell assembly 120, the module housing 200 may be coupled to end plates 400 provided on the front and rear surfaces of the cell assembly 120.

[0058] The battery module 100 according to this embodiment may have a twin structure. Here, the twin structure may refer to a structure in which the battery module 100 includes two cell assemblies 120. In the twin structure, the two cell assemblies 120 housed in one module housing 200 may be arranged along the length direction (y-axis direction). In addition, the two cell assemblies 120 housed in one module housing 200 may be arranged such that the front or rear surfaces of the cell assemblies, where the electrode leads are located, face each other.

[0059] Specifically, referring to FIG. 3 , the battery module 100 according to this embodiment includes a first cell assembly 121 and a second cell assembly 122. As shown in FIGS. 2 and 3 , the cell assembly 120 is inserted into the module housing 200 along its length, so that one of the front and rear surfaces of the first cell assembly 121 is located inside the module housing 200 and the other is located outside, i.e., on the open side, of the module housing 200. In a conventional structure, two end plates 400 are provided for each of the first cell assembly 121 and the second cell assembly 122, and two openings are formed in each end plate 400 to expose the negative and positive terminal bus bars 133, 134. However, in the structure of this embodiment, one of the front and rear surfaces of the first cell assembly 121 and the second cell assembly 122 faces each other inside the module housing 200, and the other is located outside. Therefore, the number of end plates 400 provided in the first cell assembly 121 and the second cell assembly 122 is reduced from four to two, and thereby the number of openings formed in the end plates 400 can be reduced.

[0060] 2, 3, and 7, in the twin-structure battery module 100 according to this embodiment, the terminal bus bars 133, 134 are located inside the module housing 200, and therefore, as shown in Figures 2 and 3, the module housing 200 may have a module terminal unit 201 for connecting the terminal bus bars 133, 134 of Figure 7 to an external device. The module terminal unit 201 may be formed on the top surface of the module housing 200.

[0061] 5 can be attached to the module terminal unit 201, and the module terminal unit 201 may have an inwardly recessed shape to facilitate attachment of the terminal assembly 300. The module terminal unit 201 may be formed in the center of the module housing 200. Here, the center may be a portion including the center of the battery module 100 in the length direction (y-axis direction).

[0062] The module housing 200 may include two module terminal units 201. Each module terminal unit 201 may include two terminal holes 202 corresponding to the terminal bus bars 133 and 134. In this case, one of the two terminal holes 202 may be for connection to one of the positive and negative electrodes of the first cell assembly 121, and the other may be for connection to one of the positive and negative electrodes of the second cell assembly 122.

[0063] In the cell assemblies 120 of this embodiment, the terminal bus bars 133, 134 may be arranged offset to one side in the stacking direction. Thus, the four terminal bus bars 133, 134 of two cell assemblies 120 housed in the same module housing 200 may be arranged to cross each other in one direction. Therefore, two cell assemblies 120 may all correspond to one module terminal unit 201, and two terminal holes 202 included in one module terminal unit 201 may each correspond to one of the terminal bus bars 133, 134 included in the first cell assembly 121 and the second cell assembly 122. In this case, the terminal bus bars 133, 134 of the first cell assembly 121 and the second cell assembly 122 corresponding to the two terminal holes 202 of one module terminal unit 201 may have different poles.

[0064] More specifically, the negative electrode of the second cell assembly 122, the positive electrode of the first cell assembly 121, the positive electrode of the second cell assembly 122, and the negative electrode of the first cell assembly 121 may be arranged in the stacking direction. As such, in the twin structure according to this embodiment, the terminal bus bars 133, 134 of the two cell assemblies 120 may be arranged in the order of negative, positive, positive, negative. However, this is not necessarily the case, and they may be arranged in the order of positive, negative, negative, positive, or in a different order depending on the design. For this, see FIG. 19, which will be described later.

[0065] As shown in FIG. 8, busbar bolts 138 are attached to the terminal busbars 133 and 134. After the cell assembly 120 is inserted into the module housing 200, the busbar bolts 138 may be positioned to correspond to the terminal holes 202 of FIG. 2. The busbar bolts 138 are connected to terminal assemblies 300 located outside the module housing 200 through the terminal holes 202, thereby electrically connecting the cell assembly 120 to an external device, for example, the cell assembly 120 of an adjacent battery module 100. Meanwhile, in the case of a battery module 100 located at the outermost position in a battery pack 1000 (see FIG. 9), two cell assemblies 120 included in one battery module 100 may be electrically connected by a terminal assembly 300 for HV connection. The outermost battery module 100 may also be electrically connected to a BDU 190 (see FIG. 17) through the terminal assembly 300.

[0066] 2 to 5, the battery module 100 according to this embodiment includes a terminal assembly 300 located in a region between the first sub-module 100a and the second sub-module 100b, overlapping with a module extension portion located where the first sub-module 100a and the second sub-module 100b face each other. The terminal assembly 300 may be used to provide an HV connection to the battery module 100. The terminal assembly 300 may be located on the module terminal portion 201 of the module housing 200. The terminal assembly 300 may be electrically connected to the cell assembly 120 by connecting to terminal bus bars 133 and 134 within the module housing 200.

[0067] 7 and 9, the terminal assembly 300 can electrically connect adjacent battery modules 100. More specifically, the terminal assembly 300 can connect to the positive electrode of the terminal bus bars 133, 134 of one battery module 100 and to the negative electrode of the terminal bus bars 133, 134 of the adjacent battery module 100. The terminal assembly 300 can also electrically connect the BDU 190 to the adjacent battery module 100. Depending on the position, the terminal assembly 300 can also be provided to electrically connect two cell assemblies 120 of the outermost battery module 100.

[0068] 3 to 5, the terminal assembly 300 according to this embodiment can be connected to the terminal bus bars of the first sub-module 100a and the second sub-module 100b through openings 211 and 215 formed in a portion of the module housing 200 that overlaps the module extension. A bracket 220 is positioned in the openings 211 and 215, and a sealing member can be formed between the bracket 220 and the terminal assembly 300. This sealing member can ensure a sealing structure against insulating oil for direct cooling of the module when an electrical connection structure is formed through the structure in which the terminal assembly 300 is connected to the bracket 220.

[0069] The terminal assembly 300 according to this embodiment includes a flexible connecting cable 310, a terminal housing 320 coupled to the connecting cable 310, and an upper cap 330 covering the upper portion of the terminal housing 320 connected to the bracket 220. Furthermore, the terminal assembly 300, which connects terminal bus bars having opposite polarities, can electrically connect adjacent first and second battery modules. The first and second battery modules are electrically connected by a first terminal assembly 300a and a second terminal assembly 300b shown in FIG. 5, and the first and second terminal assemblies 300a and 300b can be connected to each other by a fixing member 350.

[0070] The module housing 200 according to this embodiment is formed of a highly rigid material, which may include a composite material such as fiber reinforced plastic (FRP). The highly rigid module housing 200 not only controls battery cells with high capacity and high swelling, but also minimizes the pack housing structure by acting as a pack housing, ensuring long-term sealing reliability. In addition, the upper part of the module housing 200 acts as a pack cover, allowing the elimination of an upper housing from the battery pack.

[0071] The module housing 200 according to this embodiment may include at least two plates spaced apart from each other, and a space may be formed between the plates, where a refrigerant may flow.

[0072] According to this embodiment, the refrigerant for cooling is a fluid, and the refrigerant can directly contact the cell assemblies 120, other electrical components, and the bus bar frame 130 in the battery module 100. At this time, since the refrigerant must be electrically insulated, the refrigerant according to this embodiment may be an insulating material. For example, the refrigerant may be insulating oil.

[0073] As described above, the refrigerant directly contacts the cell assemblies 120 and other electrical components that generate heat within the battery module 100, as well as the bus bar frame 130, and transfers heat thereto, thereby directly cooling them. This improves cooling efficiency compared to conventional methods of indirectly cooling the battery module using a heat sink, thereby extending the life of the battery.

[0074] Fig. 9 is a perspective view showing a battery pack formed by connecting a plurality of battery modules of Fig. 4. Fig. 10 is a front view showing adjacent battery modules connected together.

[0075] Referring to FIG. 9, a battery pack 1000 according to this embodiment includes a plurality of battery modules 100, and a first battery module and a second battery module included in the plurality of battery modules 100 are adjacent to each other, and the first battery module 100a and the second battery module 100b can be electrically connected by a first terminal assembly 300a and a second terminal assembly 300b.

[0076] Referring to FIG. 5, as described above, the first terminal assembly 300a and the second terminal assembly 300b are connected to each other by a fixing member 350, and the fixing member 350 can be fastened to the module housing 200 by a fastening member 360.

[0077] 4, 9, and 10, adjacent battery modules 100 may be coupled to each other using module fastening members 1200, such as bolts, with the flanges 200F formed on the side surfaces of the module housings 200 overlapping each other. In this case, one flange 200F may be formed on each of the upper and lower sides of the side surface of the module housing 200. This coupling structure eliminates the need for a pack housing and minimizes the number of pack housing components. In particular, because the module fastening members 1200 are coupled to the overlapping portions of the flanges 200F formed on the upper and lower sides of the side surfaces of the flanges 200F, components such as rigid beams may be omitted. In other words, the coupling portions, including the module fastening members 1200, at the overlapping portions of the flanges 200F can function as rigid beams in the pack structure. A plurality of module fastening members 1200 may be formed spaced apart from each other along the length direction (y-axis direction) of the battery module 100.

[0078] The battery pack 1000 according to this embodiment also includes a pack frame 1100 that protects the plurality of battery modules 100 from external impact. The pack frame 1100 may include a front frame 1110, a rear frame 1120, a first side frame 1130, and a second side frame 1140. The front frame 1110 and the rear frame 1120 may extend along the length direction (y-axis direction) of the battery module 100, and the lengths of the front frame 1110 and the rear frame 1120 may be similar to the length of the battery module 100. The first side frame 1130 and the second side frame 1140 may extend along the width direction (x-axis direction) of the battery module 100. The lengths of the first side frame 1130 and the second side frame 1140 may be proportional to the number of battery modules 100 included in the battery pack 1000.

[0079] After the plurality of battery modules 100 are aligned in one direction (x-axis direction) and adjacent battery modules 100 are coupled to each other via flange portions 200F and module fastening members 1200, the front frame 1110 may be coupled to the outermost battery module 100 via a separate fastening member. After the other outermost battery module 100 is coupled to one side of the BDU 190, the rear frame 1120 may be coupled to the other side of the BDU via a separate fastening member. After the cooling assembly 600 and LV cable 800 of FIG. 13 are attached to the front or rear of the plurality of battery modules 100, the first side frame 921 and the second side frame 922 may be coupled to cover the front or rear of the plurality of battery modules 100.

[0080] The overall structure of the pack frame 1100 according to this embodiment may have a shape that exposes the upper and lower portions of the battery modules 100. That is, the pack frame 1100 may not include a separate upper cover that covers the upper portions of the plurality of battery modules 100 and a separate lower cover that supports the lower portions of the plurality of battery modules 100. In this case, the upper and lower portions of the module housing made of a highly rigid material may form the upper and lower covers of the pack frame 1100.

[0081] Therefore, the pack frame 1100 of this embodiment covers the front, back, left and right sides of the battery module assembly in which multiple battery modules 100 are aligned to ensure the structural stability of the battery pack 1000, but unlike conventional battery packs, it is possible to omit a frame structure provided on the top or bottom, which has the advantage of being able to increase energy density and space efficiency.

[0082] Fig. 11 is a perspective view showing the combination of a battery module and a cooling assembly according to an embodiment of the present invention. Fig. 12 is a view showing the front or rear of a battery module according to an embodiment of the present invention. Figs. 13 and 14 are front views showing the combination of a cooling assembly with a battery pack according to an embodiment of the present invention. Fig. 13 is a view from Fig. 9 with the first side frame 1130 removed, viewed in the direction P of Fig. 9, and Fig. 14 is a view from Fig. 9 with the second side frame 1140 removed, viewed in the direction Q of Fig. 9.

[0083] 11 to 14, the battery pack 1000 of this embodiment may include a cooling assembly 600 that supplies a refrigerant to the inside of the battery module 100.

[0084] The cooling assembly 600 may include a cooling pipe 610 for moving a refrigerant and a cooling port 620 for the inflow and outflow of the refrigerant. The cooling port 620 may be coupled to a cooling port opening 420 formed in the end plate 400, thereby allowing the refrigerant to be supplied from the cooling pipe 610 to the inside of the battery module 100. The refrigerant introduced into the battery module 100 can cool the battery cells by directly contacting the battery cells. Therefore, the direct cooling method of this embodiment can significantly improve cooling efficiency compared to conventional indirect cooling methods using heat transfer members and cooling fins.

[0085] The cooling port 620 may have holes on both sides for connection to the end plate 400, and the cooling port fastening members 760 may be inserted into the holes to stably connect the cooling port 620 to the end plate 400. Here, a sealing member such as an O-ring may be provided between the cooling port 620 and the end plate 400 to prevent leakage of the refrigerant around the cooling port 620.

[0086] Here, all of the cooling ports 620 connected to each battery module 100 may be connected to one cooling pipe 610, but this is not necessarily the case. As shown in Figures 13 and 14, some of the cooling ports 620 may be connected to one cooling pipe 610 and the other part may be connected to another cooling pipe 610. By changing the connection structure of the cooling pipe 610 in this way, the flow of the refrigerant can be changed, thereby optimizing cooling efficiency.

[0087] 9 and 11 to 14, in the battery pack 1000 according to this embodiment, the plurality of cooling pipes 610 may be formed at the upper or lower ends of the front and rear surfaces of the battery module 100. Referring to FIGS. 13 and 14, in one battery module 100, if the first cooling pipe 610 arranged on the front surface of the battery module 100 adjacent to the first side frame 1130 in FIG. 9 is arranged at the lower end of the front surface of the battery module 100, the second cooling pipe 610 arranged on the rear surface of the battery module 100 adjacent to the second side frame 1140 in FIG. 9 may be arranged at the upper end of the rear surface of the battery module 100. Conversely, in one battery module 100, if the first cooling pipe 610 arranged on the front surface of the battery module 100 adjacent to the first side frame 1130 in FIG. 9 is arranged at the upper end of the front surface of the battery module 100, the second cooling pipe 610 arranged on the rear surface of the battery module 100 adjacent to the second side frame 1140 in FIG. 9 may be arranged at the lower end of the rear surface of the battery module 100. In this case, the refrigerant in the cooling pipe 610 disposed at the lower end of the front or rear surface of the battery module 100 may be supplied to the inside of the battery module 100 through the cooling port 620 connected to the cooling pipe 610, and the refrigerant in the cooling pipe 610 disposed at the upper end of the front or rear surface of the battery module 100 may be supplied to the inside of the battery module 100 through the cooling port 620 connected to the cooling pipe 610. According to this embodiment, the cooling pipe 610 serving as the refrigerant inlet may be disposed at the bottom of the battery module, and the cooling pipe 610 serving as the refrigerant outlet may be disposed at the top of the battery module. In this case, the refrigerant flows into the battery module through the cooling port 620 connected to the cooling pipe 610 disposed at the bottom of the battery module, and the refrigerant is discharged to the outside of the battery module through the cooling port 620 connected to the cooling pipe 610 disposed at the top of the battery module, thereby making it possible to evenly distribute insulating oil within the battery module 100 and thereby minimize cooling deviation between battery cells.

[0088] 14, some of the cooling pipes 610 according to this embodiment may have one end connected to a cooling port 620 at the upper end of a battery module, and the other end connected to a cooling port 620 at the lower end of an adjacent battery module. In this case, the cooling pipe 610 may have a bent portion 612, which may allow the cooling assemblies of adjacent battery modules to be connected in series.

[0089] In order for the cooling pipe 610 according to this embodiment to be attached to the battery module 100, locking portions 650 may be formed on the front and rear surfaces of the battery module 100. The locking portions 650 may be formed on the front and rear surfaces of the battery module 100, and one may be formed on each of the upper and lower ends of one surface of the battery module 100. The cooling pipe 610 is connected to the cooling port 620, and the cooling port 620 may be coupled to the end plate 400 by a cooling port fastening member 760. In this case, the locking portions 650 may serve as a structure that supports the cooling port fastening member 760 so that the cooling pipe 610 is stably attached to the battery module 100.

[0090] The cooling port 620 may have a concave shape to mate with the outer shape of the cooling pipe 610. The cooling pipe 610 may be made of a flexible material, and the radius of the mounting portion of the locking portion 650 to which the cooling pipe 610 is attached may be smaller than the radius of the cooling pipe 610, so that the cooling pipe 610 can be inserted and coupled to the locking portion 650. This is just an example, and the radius of the mounting portion of the locking portion 650 does not necessarily have to be smaller than the radius of the cooling pipe 610. The locking portion 650 may be formed to have a structure that wraps around a portion of the outer surface of the cooling pipe 610.

[0091] Meanwhile, as shown in Figures 13 and 14, the LV cable 800 of this embodiment can be provided for connection between battery modules 100. Therefore, as shown in Figures 13 and 14, the LV connection structure of this embodiment can be simpler than the conventional LV connection structure, thereby improving space efficiency.

[0092] The end plate 400 according to this embodiment may serve to protect the cell assembly 120 and the electrical components connected thereto from external physical impact by sealing the open side of the module housing 200. To this end, the end plate 400 may be made of a material having a predetermined strength. For example, the end plate 400 may include a metal such as aluminum.

[0093] The end plate 400 can be coupled to the module housing 200 while covering the bus bar frame 130 located on one side of the cell assembly 120. Each corner of the end plate 400 can be coupled to a corresponding corner of the module housing 200 by a method such as welding.

[0094] Two end plates 400 may be provided to seal the two open sides of the module housing 200. Here, the end plate provided on the front side and the end plate provided on the rear side of the module housing 200 may have the same shape. This is to simplify the process and minimize costs by manufacturing the two components that make up the battery module 100 in the same shape.

[0095] The end plate 400 may have a vertically or horizontally symmetrical shape. Specifically, the end plate 400 may include a break portion opening 410, a cooling port opening 420, and a CMC opening 460, each of which may have a vertically symmetrical shape. The end plate 400 may also include two break portion openings 410, which may be positioned symmetrically with respect to the vertical bisector (or vertical centerline) of the end plate 400. The end plate 400 may also include two cooling port openings 420, which may be positioned symmetrically with respect to the vertical bisector (or vertical centerline) of the end plate 400.

[0096] That is, the end plate 400 may have a symmetrical shape with respect to a first center line, which may be a line that divides the end plate 400 into two equal parts vertically. The end plate 400 may also have a symmetrical shape with respect to a second center line, which may be a line that divides the end plate 400 into two equal parts horizontally. In this case, the symmetrical shapes in the vertical and horizontal directions may be determined based on the overall shape, excluding components located on the outside, such as the mounting portion 490.

[0097] As such, since the end plate 400 has an overall vertically or horizontally symmetrical structure, even if the battery module 100 is placed upside down (i.e., the battery module is inverted), it is easy to connect to external devices, and effects such as process simplification, cost reduction, and ease of design are achieved.

[0098] Figure 15 is a schematic diagram showing the connection relationship of a cooling assembly in a battery pack according to a comparative example, and Figure 16 is a schematic diagram showing the connection relationship of a cooling assembly in a battery pack according to an embodiment of the present invention.

[0099] 15(a), in a refrigerant flow path through a plurality of battery modules 30, cooling assemblies are connected in parallel so that the refrigerant inlet and refrigerant outlet constituting the refrigerant flow path are arranged in parallel. That is, the refrigerant flows into the plurality of battery modules 30 in a parallel configuration, and the refrigerant that has passed through the plurality of battery modules 30 is discharged to the outside of the battery modules in a parallel configuration. In contrast, referring to FIG. 15(b), in a refrigerant flow path through a plurality of battery modules 30, cooling assemblies are connected in series so that the refrigerant inlet and refrigerant outlet constituting the refrigerant flow path are arranged in series. That is, the refrigerant flows into the plurality of battery modules 30 in a serial configuration, and the refrigerant that has passed through the plurality of battery modules 30 is discharged to the outside of the battery modules in a serial configuration.

[0100] In the battery pack according to FIG. 15(a), the total flow rate can be increased and the temperature deviation between the multiple battery modules can be reduced, and in the battery pack according to FIG. 15(b), the total flow rate can be decreased and the temperature deviation between the multiple battery modules can be increased.

[0101] 16, in the battery pack according to this embodiment, a refrigerant flow path through which a refrigerant passes through the interior of a plurality of battery modules 100 may have a flow path that connects the plurality of battery modules 100 in series. Specifically, the refrigerant flow path may have a flow path in which N (N is a natural number of two or more) battery modules are connected in parallel, and a plurality of module groups, each including the N parallel-connected battery modules, are arranged and the module groups are connected in series to each other.

[0102] Alternatively, each of the plurality of module groups may include an inlet portion through which the refrigerant flows into the battery module 100 and an outlet portion through which the refrigerant flows out of the battery module 100, and the module groups may be arranged such that the inlet portions and outlet portions of the module groups are alternately arranged based on one side of the battery module 100.

[0103] As described above, according to this embodiment, by configuring the series-parallel mixed refrigerant flow passages, it is possible to form a refrigerant flow passage having an optimum flow rate and temperature deviation.

[0104] 17 and 18 are views showing the combination of a battery module and a pack frame according to an embodiment of the present invention.

[0105] As shown in Fig. 10, a frame fastening portion 230 for coupling to a pack frame during assembly of a battery pack may be formed on a side of the module housing. As shown in Fig. 11, the frame fastening portion 230 may correspond to one of the holes formed in the mounting portion 490 of the end plate, and may be fastened to the pack frame when the mounting portion 490 and the pack frame are coupled together.

[0106] 9, 17, and 18, mounting holes 900 are formed in the first side frame 1130 and the second side frame 1140, and the mounting holes 900 may be arranged to correspond to holes formed in the mounting portions 490 of the end plates 400. At this time, frame fastening members 1105 are inserted to pass through the mounting holes 900 and the holes formed in the mounting portions 490, thereby coupling the battery module 100 to the first side frame 1130 or the second side frame 1140. In addition, the inserted frame fastening members 1105 may be inserted into the frame fastening portions 230 of the module housing 200 shown in FIG. 10, thereby further improving structural stability.

[0107] FIG. 19 is a plan view showing a structure in which a terminal assembly is connected in a battery pack according to an embodiment of the present invention.

[0108] 19, a plurality of terminal assemblies 300 may electrically connect adjacent battery modules across the P region to connect the battery modules to an external power source or a Battery Disconnect Unit (BDU) 190, thereby forming a high voltage (HV) connection structure. The plurality of terminal assemblies may be located at overlapping portions of module extensions where a first sub-module and a second sub-module that constitute one battery module face each other, and may extend parallel to the direction in which the battery cells are stacked.

[0109] As described above, in the battery pack 1000 according to this embodiment, the connections between the plurality of battery modules 100 and between the battery modules 100 and the BDU 190 are formed via the terminal assemblies 300 on the upper side of the module housing, so that the HV connection structure can be relatively simplified and a margin for assembly tolerance can be ensured.

[0110] Conventional battery packs include battery modules, cooling structures such as heat transfer pads and heat sinks, and a pack housing, which includes multiple metal components such as a pack cover, pack frame, cross beam, underguard, etc. In contrast, the battery pack of the present invention has a direct cooling structure using insulating oil circulation, does not have any separate cooling structures other than sealing components, and is constructed by connecting highly rigid battery modules, thereby minimizing the pack housing.

[0111] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0112] 100 battery modules 120 Cell Assembly 130 Busbar Frame 200 Module Housing 200A opening 210 Cooling fin 220 Bracket 300 Terminal Assembly 310 Connecting Cable 320 Terminal Housing 330 Upper Cap 350 Fixing member 360 Fastening members

Claims

1. a battery cell assembly in which a plurality of battery cells are stacked, and a first sub-module and a second sub-module, each of which includes a bus bar that electrically connects the battery cells and a bus bar frame that covers the battery cell assembly on at least one side; a module housing that simultaneously houses the first sub-module and the second sub-module; and a terminal assembly located in a region overlapping the region between the first sub-module and the second sub-module; A battery module in which an opening is formed in a portion of the module housing, and the terminal assembly is connected to terminal bus bars of the first sub-module and the second sub-module through the opening.

2. a bracket located in the opening; and The battery module of claim 1 , further comprising a sealing member formed between the bracket and the terminal assembly.

3. The battery module of claim 2 , wherein the terminal assembly includes a flexible connecting cable, a terminal housing coupled to the connecting cable, and an upper cap covering an upper portion of the terminal housing connected to the bracket.

4. The battery module according to claim 1 , wherein the module housing is formed of a highly rigid material, and the highly rigid material includes a fiber reinforced plastic (FRP) as a composite material.

5. a flange portion formed on a side surface of the module housing; and The battery module of claim 1 , further comprising a module fastening member coupled to the flange portion.

6. A system including a plurality of modules according to any one of claims 1 to 5, The first battery module and the second battery module included in the plurality of battery modules are adjacent to each other, the first battery module and the second battery module are electrically connected by a first terminal assembly and a second terminal assembly; The first terminal assembly and the second terminal assembly are connected to each other by a fixing member.

7. 7. The battery pack of claim 6, wherein flange portions of the first battery module and the second battery module overlap each other, and the first battery module and the second battery module are coupled together by a module fastening member that penetrates the overlapping flange portions.

8. The battery pack according to claim 7 , wherein a joint including the module fastening member forms a rigid beam of the battery pack.

9. The battery pack according to claim 6 , wherein the fixing member is fastened to the module housing by a fastening member.

10. 7. The battery pack according to claim 6, further comprising a pack frame enclosing the plurality of battery modules on the front, rear, left and right sides, respectively, and the pack frame is separated into a plurality of pack frames corresponding to the plurality of battery modules on the front, rear, left and right sides, respectively.

11. The module housing further includes a frame fastening portion formed on a side surface thereof, The battery pack according to claim 10 , wherein at least one of the pack frames has a frame fastening member inserted into the frame fastening portion to be connected to the battery module.

12. At least one of the pack frames has a mounting hole formed therein; the mounting holes are arranged to correspond to holes formed in mounting portions of end plates of the battery modules; The battery pack of claim 11 , wherein the frame fastening member is inserted into the mounting hole and a hole formed in the mounting portion.

13. The battery pack according to claim 10 , wherein the entire structure of the pack frame has a shape that exposes the upper and lower portions of the battery modules.

14. 14. The battery pack according to claim 13, wherein the upper and lower parts of the module housing, which are made of a highly rigid material, form upper and lower covers of the pack frame.

15. The battery pack of claim 6 , wherein the first terminal assembly and the second terminal assembly are connected to terminal bus bars having different polarities.

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