Battery pack

Abstract

A battery pack according to the present invention includes a battery module accommodating a plurality of battery cells, a pack case in which a plurality of the battery modules are horizontally stacked and accommodated, and a retention bar extending along a stacking direction of the battery modules and coupled to the pack case by applying pressure to upper surfaces on both sides of the stacked battery modules.

Description

[Technical field]

[0001] The present invention relates to a battery pack.

[0002] More particularly, the present invention relates to a battery pack capable of restricting the movement in the height direction of a plurality of battery modules contained within the battery pack.

[0003] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0143937 dated October 26, 2021, and all contents disclosed in the documents of the relevant Korean patent application are incorporated herein by reference. [Background technology]

[0004] Recently, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. Secondary batteries are also attracting attention as energy sources for electric vehicles and hybrid electric vehicles, which are being proposed as a solution to address air pollution caused by existing gasoline and diesel vehicles that use fossil fuels. Therefore, the types of applications that use secondary batteries are becoming increasingly diverse due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future.

[0005] In addition, there is an increasing demand for battery modules housing a number of secondary batteries electrically connected in series or parallel and battery packs including the battery modules as power sources for energy storage systems (ESS) and electric vehicles.

[0006] Such a battery module or battery pack includes an external housing made of a metal material for storing and protecting a plurality of secondary batteries from external impacts.

[0007] The battery pack may be configured in various forms, such as by installing the battery modules in a plurality of separate receiving grooves separated by partition walls, or by receiving a plurality of battery modules at once in one battery pack case, etc. The form of the battery pack may vary depending on the shape, size, electrical connection structure, etc. of the battery modules to be received.

[0008] When a plurality of battery modules are accommodated in one battery pack case at a time, an adhesive resin may be applied to the bottom of the pack case to bond and fix the battery modules. In this case, the adhesive resin may not be uniformly filled between the battery modules and the pack case, so that the height of the battery modules may not be uniform. In the case of a large battery module accommodating a large number of battery cells, the pressure applied to the adhesive resin layer by its own weight is large, so the problem of uneven height may not be so serious. However, when a small battery module accommodating a relatively small number of battery cells is accommodated in a battery pack, it may be difficult to uniformly connect bus bars between the modules due to the uneven height.

[0009] FIG. 1 is a perspective view of an expandable battery module proposed by the present applicant, and FIG. 2 is a partial perspective view showing a state in which a plurality of expandable battery modules are accommodated in a pack case.

[0010] The applicant has arranged battery cells in a row in the length direction to form a length direction unit cell, and stacked the length direction unit cells in two or more rows in the thickness direction of the battery cell to form a battery cell assembly. Also, according to the shape of the battery cell assembly, a module case has been manufactured in a shape that extends long in the length direction and surrounds the battery cell assembly. In such a battery module, a relatively small number of battery cells are accommodated in each module case, and the battery modules are stacked in the length direction or thickness direction of the battery cell like Lego blocks, so that a battery pack can be freely configured in consideration of the space in which the battery module is installed or the installation space of the battery pack. In this way, the battery module proposed by the applicant can be called an expandable battery module because various types of battery packs can be manufactured according to the stacking (design) method.

[0011] However, the expandable battery module 10 is relatively lightweight since it contains a small number of battery cells. Therefore, when a plurality of battery modules 10 are contained in a pack case filled with an adhesive resin layer, the height of the battery module in the width direction (perpendicular to the length direction) is not uniform as shown in FIG. 2. In this case, when an electrical component (high voltage bus bar) is welded to a terminal bus bar T formed in the center of the battery module along the width direction of the battery module as shown in FIG. 2, deviation may occur and a gap may occur at the welded portion. In particular, when a heat sink is installed on the top of the battery module, if the height of the battery module is not uniform, a gap may occur between the heat sink and the battery module or between the heat sink and the adhesive resin applied to the top of the battery module, which may increase the thermal resistance.

[0012] FIG. 3 is a schematic diagram showing swelling occurring when stacking battery modules 10 having expandability proposed by the present applicant.

[0013] For example, by not filling the adhesive resin layer, or even if it is filled, by uniformly pressurizing the battery module 10 and assembling it into the pack case, it is possible to eliminate height unevenness as shown in Figure 2 during assembly and assemble the battery module into the pack case at a uniform height.

[0014] However, when multiple battery modules are stacked and stored in a battery pack, battery cells in the battery module swell while charging and discharging under usage conditions, resulting in assembly deformation. When multiple battery cells in a battery module swell, the module case is also subjected to stress. This causes deformation of the assembly form of the expandable battery module, as shown in the lower drawing of FIG. 3. When assembly deformation occurs, electrical connection members such as sensing cables and sensing terminals connecting each battery module are also deformed, which can cause poor contact during electrical transmission to the BMS or other external devices, and in the worst case, can cause disconnection and electrical connection to be cut off.

[0015] Therefore, when a plurality of battery modules are stacked and assembled inside a pack case, it can be said that there is a demand for development of a technology that can make the height of each battery module uniform and prevent assembled deformation of the battery modules due to swelling when the battery pack is used. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Korean Patent No. 10-1979888 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery pack in which the height of the battery modules can be maintained uniform when assembling a plurality of battery modules into a pack case and even after assembly.

[0018] Another object of the present invention is to provide a battery pack having a connection structure that can maximize the utilization of the internal space by minimizing fastening points and stably fixing the battery module within the pack, and can improve the connection rigidity between the battery module and the pack case. [Means for solving the problem]

[0019] To solve the above problems, a battery pack according to the present invention includes a battery module accommodating a plurality of battery cells, a pack case in which a plurality of the battery modules are horizontally stacked and accommodated, and a retention bar extending along a stacking direction of the battery modules and coupled to the pack case while applying pressure to upper surfaces on both sides of the stacked battery modules.

[0020] As an example, the battery module may house a battery cell assembly in which a plurality of longitudinal unit cells, each of which is formed by arranging a plurality of battery cells in a row in a longitudinal direction, are stacked in a thickness direction of the battery cells, and the battery module may have a rectangular parallelepiped shape extending elongated in the longitudinal direction to house the battery cell assembly.

[0021] As a specific example, the longitudinal unit cell may be a cell in which battery cells are arranged in two rows in the longitudinal direction, a terminal bus bar may be connected between the battery cells arranged in the longitudinal direction, and an end of the terminal bus bar may be exposed to an upper portion of the battery module.

[0022] The battery pack may further include a high voltage bus bar extending in a width direction of the battery modules and coupled to a terminal bus bar of each of the battery modules.

[0023] As an example, the pack case may include an upper frame, a lower frame on which the battery modules are stacked and mounted, and front, rear, left and right side frames positioned between the upper and lower frames and surrounding the stacked battery modules.

[0024] Specifically, the lower frame and the side frame may be integrally formed.

[0025] In addition, the front and rear side frames and the left and right side frames may extend in a direction perpendicular to and in a stacking direction of the battery modules, respectively, and the retention bar may be coupled to the left and right side frames.

[0026] As an example, the left and right side frames may have coupling protrusions formed on inner surfaces facing the battery module, and the retention bar may be coupled to upper surfaces of the coupling protrusions to pressurize upper surfaces of both sides of the battery module.

[0027] As a more specific example, an insertion groove into which one side of the retention bar is inserted may be formed on the inner surface of the coupling protrusion of the left and right side frames, and one side of the retention bar may be inserted into the insertion groove, and at the same time, the retention bar may be coupled to the upper surface of the coupling protrusion by a fastening member.

[0028] As another example, the retention bar may include an upper plate and a bent portion bent downward from the upper plate, and when the upper plate presses against both upper surfaces of the battery module and the bent portion is inserted into the gap between the inner surfaces of the left and right side frames and the battery module, a fastening member may pass through the upper plate and the bent portion and be coupled to the coupling protrusion, thereby coupling the retention bar to the left and right side frames.

[0029] In the above example, an insertion groove is formed on the inner surface of the coupling protrusion of the left and right side frames, and one side of the upper plate of the retention bar can be inserted into the insertion groove.

[0030] For example, an adhesive resin layer may be filled between the battery module and the lower frame.

[0031] Also, an adhesive resin layer may be filled between the battery module and the upper frame.

[0032] In the above example, a heat sink may be provided between the upper frame and the adhesive resin layer, and an insulating member may be provided between the upper frame and the heat sink. Effect of the Invention

[0033] According to the present invention, when a plurality of battery modules are assembled into a pack case, a uniform height can be maintained, which facilitates welding of bus bars for electrical components, and prevents gaps from occurring between the battery modules when a heat sink is installed on the upper portion.

[0034] In addition, even after the battery module is assembled and housed in the pack case, deformation in height due to swelling can be prevented.

[0035] In addition, when assembling the battery module into a pack, the number of fastening points can be minimized and the battery module can be stably fixed inside the pack, thereby maximizing the utilization of the internal space, and a battery pack with a connection structure that can improve the connection rigidity between the battery module and the pack case can be provided. [Brief description of the drawings]

[0036] [Figure 1] FIG. 2 is a perspective view of an expandable battery module proposed by the present applicant. [Diagram 2]FIG. 2 is a partial perspective view showing a state in which a plurality of expandable battery modules are housed in a pack case. [Diagram 3] FIG. 2 is a schematic diagram showing swelling occurring when stacking expandable battery modules proposed by the present applicant; [Figure 4] FIG. 2 is an exploded perspective view showing an example of an expandable battery module. [Diagram 5] FIG. 2 is a perspective view showing the structure of a pack case of the battery pack according to one embodiment of the present invention. [Figure 6] 1 is a side cross-sectional view showing an embodiment of a coupling structure of a retention bar, a pack case, and a battery module, which is a main part of the present invention. [Figure 7] 4A to 4C are side cross-sectional views showing various embodiments of a coupling structure between a retention bar, a pack case, and a battery module, which are the main parts of the present invention; [Figure 8] 4A to 4C are perspective views showing a process in which a battery module is assembled into the battery pack case of the present invention; [Figure 9] 1 is a schematic cross-sectional side view showing a connection structure of a battery pack according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] BEST MODE FOR CARRYING OUT THEINVENTION

[0038] The present invention will be described in detail below. Prior to this, the terms and words used in the specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meanings, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to best describe his / her invention.

[0039] As used throughout the present specification, terms such as "comprise" or "have" are intended to specify the presence of features, numerals, steps, operations, components, parts, or combinations thereof described in the specification, but are to be understood as not precluding the possibility of the presence or addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0040] In addition, when a layer, film, region, plate, or other part is described as being "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a layer, film, region, plate, or other part is described as being "under" another part, this includes not only the case where it is "directly under" the other part, but also the case where there is another part in between. In addition, in the specification of the present invention, being "on" can include not only the case where it is upper, but also the case where it is lower.

[0041] A battery pack according to the present invention includes a battery module accommodating a plurality of battery cells, a pack case in which the plurality of battery modules are horizontally stacked and accommodated, and a retention bar extending along a stacking direction of the battery modules and coupled to the pack case while applying pressure to upper surfaces on both sides of the stacked battery modules. [Mode for carrying out the invention]

[0042] In principle, there is no restriction on the shape, size, and type of the battery module accommodated in the battery pack of the present invention. In addition, there is no restriction on the number of battery cells accommodated in the battery module. However, as described above, in the case of a small battery module having a small number of battery cells, the problem of uneven height is significant, and the need for the retention bar described below is even greater. In particular, the expandable battery module proposed by the present applicant has a module case that is elongated in the length direction, and is stacked and accommodated in one direction (horizontal direction or width direction perpendicular to the length direction of the battery module) in the pack case as shown in Figures 2 and 3, so it is suitable for applying the retention bar.

[0043] Hereinafter, the present invention will be described with reference to such an expandable battery module.

[0044] FIG. 4 is an exploded perspective view showing an example of such an expandable battery module.

[0045] As shown in FIG. 4, the expandable battery module 10 includes a battery cell assembly 11 including a lengthwise unit cell 2, and a module case 12 in which the battery cell assembly 11 is housed. The lengthwise unit cell 2 is formed by arranging two or more battery cells 1 in a row in the lengthwise direction. The battery cell 1 is a battery cell having leads formed at both ends in the lengthwise direction. Theoretically, two or more battery cells can be connected to form the lengthwise unit cell 2. However, if the lengthwise unit cell is excessively long, the electrical connection between the battery cells becomes complicated and the module case becomes long, which may reduce the rigidity. Therefore, it is preferable to arrange about two to three battery cells in the lengthwise direction. The battery cells arranged in the lengthwise direction may be electrically connected. In addition, the lengthwise unit cells 2 are stacked in a plurality of rows in the thickness direction of the battery cell 1 to form the battery cell assembly 11. The number of rows stacked in the thickness direction of the battery cell is two or more, and it is preferable to stack about two to six rows in consideration of the electrical connection between the leads led out from the battery cells. In this manner, since the expandable module houses the battery cell assemblies 11 extending in the length direction, the overall shape of the battery module 10 also has a rectangular parallelepiped shape extending in the length direction. The expandable module 10 may have a predetermined partition wall 13 between the lengthwise unit cells 11.

[0046] 4, a battery cell assembly 11 of a battery module 10 is formed by stacking two rows of longitudinal unit cells 2, each of which has two battery cells 1 connected in the longitudinal direction. A terminal bus bar is connected between the longitudinally arranged battery cells 1, and an end of the terminal bus bar is exposed to the top of the battery module 10 and can be connected to an electrical component such as a high-voltage bus bar.

[0047] The present invention includes a pack case 20 that houses the battery module.

[0048] FIG. 5 is a perspective view showing the structure of the pack case 20 of the battery pack 100 according to one embodiment of the present invention.

[0049] In FIG. 5, the X direction is the stacking direction of the battery modules (the length direction of the battery pack), the Y direction is the length direction of the battery module or the width direction of the battery pack, and the Z direction is the up-down direction, i.e., the height direction.

[0050] The pack case 20 includes an upper frame 20A, a lower frame 21 on which the battery modules 10 are stacked and mounted, and side frames 22 and 23 positioned between the upper and lower frames.

[0051] The side frames 22, 23 are provided at four locations, namely, front, rear, left and right.

[0052] 5, the lower frame 21 and the side frames 22, 23 are integrally formed to constitute a lower pack case 20B that accommodates a battery module. The lower pack case 20B may be formed by welding the side frames 22, 23 and the lower frame 21 together, or may be formed by molding a single plate. The lower frame 21 has portions 21a that extend outward on all four sides from the portion where the side frames 22, 23 are joined, and these extensions become vehicle joining portions to which fastening members are fastened so that the battery pack can be joined to a vehicle, etc.

[0053] An adhesive resin layer R may be applied to the lower frame 21, and the adhesive resin layer R serves to fix the battery module 10 when the battery module 10 is stacked on the lower frame 21.

[0054] When the battery module 10 is accommodated and fixed in the lower pack case 20B, the upper frame 20A is coupled to cover the lower pack case 20B.

[0055] After the battery module 10 is accommodated, an adhesive resin layer R may be applied between the upper frame 20A and the battery module as necessary. When a thermally conductive thermal resin is used as the adhesive resin layer R, it can perform a heat dissipation function in addition to the adhesive fixing function. Silicon resin, modified silicone resin, acrylic resin, etc. may be used as the thermally conductive thermal resin. When such a thermally conductive thermal resin is filled between the battery module 10 and the upper frame 20A or between the battery module 10 and the lower frame 21 of the lower pack case 20B, it is possible to efficiently absorb heat generated in the battery pack 100. In addition, when a heat sink 40 (heat sink) is installed under the upper frame 20A, heat can be transferred from the thermally conductive thermal resin to the heat sink 40, thereby further improving heat dissipation efficiency.

[0056] If necessary, an insulating member 50 can be installed between the upper frame 20A and the heat sink 40.

[0057] As described above, when a plurality of battery modules 10 are stacked in a specific direction and housed in one pack case 20, the battery modules 10 may not be maintained at a uniform height inside the battery pack 100 depending on the filling state of the adhesive resin layer R formed between the battery modules 10 and the pack case 20 (see FIG. 2). In addition, the battery module 10 may be displaced in a specific direction due to a swelling phenomenon caused by gas generated inside the battery module 10 during use of the battery pack 100, adversely affecting the connection state with other electrical components (see FIG. 3). The present invention is intended to prevent this, and is characterized by including a retention bar 30 to regulate the displacement of the battery module 10 in the height direction.

[0058] As described above, in this specification, the term "retention bar" refers to a bar for applying pressure to the battery module 10 to stably fix and maintain it in the pack case 20 so that there is no fluctuation in height. The retention bar 30 serves to fix and maintain a plurality of battery modules 10, and extends along the stacking direction of the battery modules 10 and is coupled to the pack case. That is, when the battery modules 10 are stacked horizontally in the pack case, the retention bar 30 is installed to extend in the stacked horizontal direction and restricts movement of the battery modules 10 in the height direction (Z direction).

[0059] FIG. 6 is a side cross-sectional view showing one embodiment of a joining structure between the retention bar 30, which is a main part of the present invention, and the pack case and battery module 10.

[0060] For ease of explanation, Fig. 5 omits the illustration of the battery module 10 and shows only the pack case, but Fig. 6 shows the battery module 10 housed in the pack case. For example, assume that the expandable battery module 10 extending long in the length direction is stacked horizontally (specifically, in the width direction of the battery module) with a gap between it and the left and right side frames 23 of the pack case 20.

[0061] Specifically, the retention bar 30 is coupled to the pack case 20 while applying pressure to the upper surfaces of both sides of the battery module 10, thereby restricting the movement of the battery module 10. That is, the retention bar 30 is provided in pairs, two of which are arranged side by side in the stacking direction of the battery modules 10, so as to apply pressure to the upper surfaces of both sides of the battery module 10.

[0062] In addition, the retention bar 30 has a pressing portion for pressing the upper surface of the battery module 10, and the pressing portion is coupled to the pack case 20. Referring to Figs. 5 and 6, the retention bar 30 is coupled to the left and right side frames 23 constituting the lower pack case 20B. The left and right side frames 23 have coupling protrusions 24 formed on their inner surfaces facing the battery module 10. The retention bar 30 is coupled to the upper surfaces of the coupling protrusions 24 to press the upper surfaces of both sides of the battery module 10. In the embodiment of Fig. 6, the retention bar 30 is formed of an upper plate 31 for pressing the upper surface of the battery module 10, and a bent portion 32 bent downward from the upper plate 31. Fastening holes 31a and 32a to which a fastening member B can be coupled are formed through one side of the upper plate 31 and the bent portion 32 at its lower portion. In addition, the lower part of the bent part 32 is provided with a coupling protrusion 24 formed to protrude from the inner surface of the left and right side frames 23 of the lower pack case 20B, and the coupling protrusion 24 is also formed with a fastening hole 24a corresponding to the fastening hole 31a, 32a. Therefore, when the fastening member B is fastened to the fastening holes 31a, 32a, 24a from above, the retention bar 30 is coupled to the coupling protrusion 24 of the side frame 23 while pressing the upper surface of both sides of the battery module 10 by the pressure from above. Since the retention bar 30 of this embodiment has an upper plate 31 and a downward bent part 32, not only the upper plate 31 presses the upper surface of both sides of the battery module 10, but also the inner surface of the downward bent part 32 connected to the upper plate presses the battery module 10. Therefore, the retention bar 30 of this embodiment firmly presses the corners of both sides of the battery module 10 to fix it, so that the plurality of battery modules 10 can be fixed and maintained more reliably. In order to reduce the weight, as shown in FIG. 6, the side frame 23 or the retention bar 30 may have a predetermined thickness reduction portion D1, D2 formed inside the bent portion.

[0063] The form of the retention bar 30 and the structure of connection with the pack case 20 are not limited to the above, and other forms are possible. For example, if the retention bar 30 is inserted into the insertion grooves of the side frames 22 and 23 of the pack case 20, the retention bar 30 can be connected to the pack case 20 without the fastening member B. However, if the fastening member B is present, the retention bar 30 can be connected to the pack case 20 more firmly. Also, it is advantageous to fasten the side surface for increasing the upper pressure force of the pack case 20 with the fastening member B. If the retention bar 30 is connected to the pack case 20 without the fastening member B, the connection work is simplified. Accordingly, it is advantageous to automate the connection work of the retention bar. However, even when fastening with fastening members, multiple fastening points can be fastened at once by a robot or the like. Therefore, the battery pack assembly process using the retention bar of the present invention can be automated, and therefore it is easy to apply to mass production processes.

[0064] Fig. 7 is a side cross-sectional view showing various embodiments of the coupling structure of the retention bar 30, which is the main part of the present invention, and the pack case and battery module 10. In the embodiment of Fig. 7, as in Fig. 6, a coupling protrusion 24 is formed on the inner surface of the side frame 23. Such a coupling protrusion 24 forms a mating coupling part facing the retention bar 30, and generates a vertical pressure force when the fastening member B is fastened at the top, so that it is suitable for restricting the movement of the battery module 10 in the height direction.

[0065] In Fig. 7(a), the retention bar 30' is formed in a flat shape without any bent portions, and with a part of the retention bar 30' positioned on the upper surface of the battery module, the retention bar 30' and the coupling protrusion 24 can be coupled with the coupling member B. Since there are no bent portions, unlike Fig. 6, the entire corner of the battery module 10 is not pressed, but the movement of the battery module 10 in the height direction can be sufficiently restricted.

[0066] 7(b) illustrates that an insertion groove 23a into which one side of a retention bar 30 is inserted is formed on the inner surface of the coupling protrusion 24 of the left and right side frames 23. The retention bar 30'' is inserted into the insertion groove 23a, and the plate-shaped retention bar 30'' is coupled to the coupling protrusion 24 from above with a fastening member B to restrict the movement of the battery module 10. In this case, since an insertion coupling is added compared to FIG. 7(a), the retention bar 30'' can be coupled to the side frames more firmly than in FIG. 7(a).

[0067] 7(c), similar to FIG. 6, a retention bar 30''' includes an upper plate 31''' and a downward protrusion 32'''. An insertion groove 23a into which one side of the retention bar 30''' is inserted is formed on the inner surface of the coupling protrusion 24 of the left and right side frames. One side of the upper plate 31''' of the retention bar 30''' is inserted into the insertion groove 23a, and the downward protrusion 32''' of the retention bar 30''' is coupled to the coupling protrusion 24 from above with a fastening member B, thereby restricting the movement of the battery module 10. In addition, in this case, since the downward protrusion 32''' is inserted between the side frame and the battery module 10, the retention bar 30 can firmly fix and maintain one side corner of the battery module.

[0068] FIG. 8 is a perspective view showing a process in which a battery module is assembled into a battery pack case according to the present invention.

[0069] First, an adhesive resin layer R is applied to the lower pack case 20B including the lower frame 21 and the side frames 22 and 23. Alternatively, the adhesive resin layer R may be filled between the battery module 10 and the lower pack case 20B through a predetermined filling hole after the battery module 10 is accommodated in the lower pack case 20B.

[0070] Next, the expandable battery modules 10 are stacked horizontally in the lower pack case 20B. In this embodiment, the horizontal direction is the length direction of the battery pack 100, and is the width direction of the battery module 10. In either case, the retention bar 30 must be installed to extend along the stacking direction of the battery modules 10.

[0071] After the battery modules 10 are placed, a pair of left and right retention bars 30 are coupled to the left and right side frames 23 of the lower pack case 20B as shown in FIG. 6. As described above, the coupling protrusions 24 are formed on the inner surfaces of the left and right side frames 23, and the coupling positions are set to be constant. Therefore, when the retention bar 30 is coupled from above onto the coupling protrusions 24, the upper surfaces of both sides of the battery module 10 are pressurized and fixed in the battery pack 100. By this coupling, the battery module 10 can be maintained in the battery pack 100 at a uniform height while pressing the adhesive resin layer R at the bottom. In this way, the present invention can be said to have a structure with minimized coupling points since a plurality of battery modules 10 can be fixed and maintained in the battery pack 100 by simply coupling the retention bar 30 to the pack case. Specifically, the battery modules 10 can be maintained in the battery pack 100 at a uniform height only by the retention bar 30 or the retention bar 30 and the adhesive resin layer R. This simple connection structure makes it possible to secure space, for example, upper and lower spaces, within the battery pack 100, and other necessary components such as electrical connection members can be installed in this space. Therefore, according to the present invention, when assembling the battery module 10 into a pack, the number of fastening points is minimized and the battery module is stably fixed within the pack, thereby maximizing the utilization of the internal space and improving the connection rigidity between the battery module 10 and the pack case 20.

[0072] When the battery modules are installed in the battery pack 100 at a uniform height by the retention bar 30, the battery modules can be electrically connected by connecting the high voltage bus bar BB to the terminal bus bar T exposed on the battery module 10. At this time, since the battery modules are arranged at a uniform height due to the unique structure of the present invention, the high voltage bus bar BB can also be welded to the battery module at a uniform height. In addition, it is possible to install and connect parts required for the battery pack, such as connecting a low voltage bus bar and a sensing cable.

[0073] Although not shown in FIG. 8, the battery pack assembly is completed by subsequently applying (filling) an adhesive resin layer R onto the battery module 10, installing a heat sink 40, and connecting an upper frame 20A.

[0074] FIG. 9 is a schematic cross-sectional side view showing the coupling structure of the battery pack of the present invention.

[0075] 9(a) shows a combination structure of a battery pack not having a height restricting member, in which an adhesive resin layer R is filled between the lower frame and the battery module 10. However, this structure is not capable of restricting the movement of the battery module 10 in the height direction, so the height of each battery module 10 is not uniform. Accordingly, when an adhesive resin layer R and a heat sink are installed on the upper part of the battery module 10, the distance between the heat sink and the battery module 10 is not uniform, and the thermal resistance between each battery module 10 and the heat sink differs, which may cause temperature deviation between the modules. In addition, deviations may occur when electrical components such as high-voltage bus bars are welded onto the modules.

[0076] 9(b), the retention bar 30 is coupled to the side frame 23 while applying pressure to the upper surfaces of both sides of the battery module 10, thereby restricting the battery module from moving in the height direction. Therefore, the battery module can be maintained at a uniform height, thereby preventing the above problem.

[0077] In addition, even after the battery pack 100 is assembled, when a swelling phenomenon as shown in FIG. 3 occurs, the battery pack 100 of the present invention has an advantage in that the battery module is restricted from moving in the height direction by the retention bar 30, and thus deformation or displacement of the battery module during assembly can be restricted.

[0078] The drawings disclosed in the present invention are for the purpose of explanation and not for the purpose of limiting the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such drawings. The scope of protection of the present invention should be interpreted according to the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present invention.

[0079] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back are used in this specification, it is obvious that such terms are used merely for convenience of explanation and may change depending on the position of the object of interest, the position of the observer, etc. [Explanation of symbols]

[0080] 1: Battery cell 2: Lengthwise unit cell 10: Battery module 11: Battery cell assembly 12: Module case 13: Bulkhead 20: Pack case 20A: Upper frame 20B: Lower pack case 21: Lower frame 22: Front and rear side frames 23: Left and right side frames 24:Joining protrusion 30: Retention bar 31: Upper plate 32: Downward bend 40: Heat sink 50: Insulating material R: Adhesive resin layer T: Terminal busbar BB: High voltage busbar 100: Battery pack

Claims

1. A battery module containing a plurality of battery cells; a pack case in which a plurality of battery modules are horizontally stacked and housed; a retention bar extending along a stacking direction of the battery modules and coupled to the pack case while applying pressure to upper surfaces of both sides of the stacked battery modules; Including, The pack case includes: The upper frame and a lower frame on which the battery modules are stacked and mounted; front, rear, left and right side frames positioned between the upper frame and the lower frame and surrounding the stacked battery modules; Including, The front and rear side frames and the left and right side frames extend in a direction perpendicular to the stacking direction of the battery modules and in the stacking direction, respectively; The retention bar is coupled to the left and right side frames of the battery pack.

2. The battery module accommodates a battery cell assembly in which a plurality of length-direction unit cells each formed by arranging a plurality of battery cells in a row in a length direction are stacked in a thickness direction of the battery cells, 2. The battery pack according to claim 1, wherein the battery module has a rectangular parallelepiped shape elongated in a length direction to accommodate the battery cell assembly.

3. The longitudinal unit cell has battery cells arranged in two rows in the longitudinal direction, The battery pack of claim 2 , wherein a terminal bus bar is connected between the battery cells arranged in the length direction, and an end of the terminal bus bar is exposed to an upper portion of the battery module.

4. 4. The battery pack according to claim 3, further comprising a high voltage bus bar extending widthwise of the battery modules and coupled to a terminal bus bar of each of the battery modules.

5. The battery pack according to claim 1 , wherein the lower frame and the side frames are integrally formed.

6. The left and right side frames have coupling protrusions formed on inner surfaces facing the battery module, The battery pack of claim 1 , wherein the retention bar is coupled to an upper surface of the coupling protrusion to press upper surfaces of both sides of the battery module.

7. An insertion groove into which one side of the retention bar is inserted is formed on the inner surface of the coupling protrusion of each of the left and right side frames, The battery pack according to claim 6 , wherein one side of the retention bar is inserted into the insertion groove, and at the same time, the retention bar is coupled to an upper surface of the coupling protrusion by a fastening member.

8. the retention bar includes an upper plate and a bent portion bent downward from the upper plate; When the upper plate presses the upper surfaces of both sides of the battery module and the bent portions are inserted into the gaps between the inner surfaces of the left and right side frames and the battery module, 7. The battery pack according to claim 6, wherein fastening members pass through the top plate and the folded portion and are coupled to the coupling protrusions, thereby coupling the retention bar to the left and right side frames.

9. The left and right side frames have an inner surface on the coupling protrusions thereof formed with insertion grooves, The battery pack according to claim 8 , wherein one side of the upper plate of the retention bar is inserted into the insertion groove.

10. The battery pack according to claim 1 , wherein an adhesive resin layer is filled between the battery module and the lower frame.

11. The battery pack according to claim 10 , wherein an adhesive resin layer is filled between the battery module and the upper frame.

12. The battery pack of claim 11 , wherein a heat sink is disposed between the upper frame and the adhesive resin layer.

13. The battery pack according to claim 12 , wherein an insulating member is installed between the upper frame and the heat sink.

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