Battery pack

Abstract

In one example, a battery pack includes a base plate, a front frame forming a front surface of the base plate, a rear frame forming a rear surface of the base plate, a pair of side frames having both ends connected to the front frame and the rear frame, and a plurality of battery cell assemblies mounted in an accommodation space formed by the front frame, the rear frame, and the pair of side frames, wherein each of the battery cell assemblies includes a battery cell unit including a plurality of cell stacks and a bus bar frame assembly mechanically and electrically connected to the plurality of cell stacks at both lateral ends from which leads of the cell stacks protrude, a first cell cross beam connected to the bus bar frame assembly in front of the battery cell unit, and a second cell cross beam connected to the bus bar frame assembly in the rear of the battery cell unit, and the plurality of battery cell assemblies are fixed to the base plate with the first cell cross beam and the second cell cross beam facing each other in the front-to-rear direction of adjacent battery cell assemblies overlapping each other.

Description

Technical Field

[0001] The present invention relates to a battery pack, and more particularly, to a battery pack that improves the structural rigidity and space utilization rate of a pack case with a cell cross beam corresponding to the full width length of the battery pack, facilitates the internal mounting of a battery cell assembly in the pack, simplifies the assembly process, and can secure a firm fixing state.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0166606 filed on December 2, 2022, and Korean Patent Application No. 10-2023-0036402 filed on March 21, 2023, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

Background Art

[0003] In order to increase the space utilization rate of a battery pack, a battery pack having a cell-to-pack structure has been proposed. The cell-to-pack structure has an advantage in that it can improve the space utilization rate of the battery pack by directly assembling a plurality of battery cells into the battery pack without modularizing them.

[0004] In the cell-to-pack structure, it is important to ensure the rigidity of the battery pack by omitting or simplifying a separate module housing. For example, a side frame can be coupled to a battery cell assembly (corresponding to a conventional battery module) in which a plurality of battery cells form a single assembly, and the side frame of the battery cell assembly housed in the pack case can be designed to serve as a cross beam of a conventional battery pack.

[0005] By the way, if multiple battery cell assemblies are arranged in the width direction of the pack case in order to increase the capacity of the battery pack, a problem arises in which the structural rigidity of the battery pack is weakened because the side frames of adjacent battery cell assemblies that face each other at the center of the battery pack in the width direction are not connected to each other.

[0006] To solve this, one could design a structure in which a center beam is placed at the longitudinal center of the battery pack, and the side frames, which were not connected to each other, are connected and fixed to the center beam. However, such a structure, in which side frames and a center beam are combined, complicates the assembly process of the battery pack, increases the weight of the battery pack due to the increased number of parts, and causes problems such as a decrease in the energy density of the battery pack due to the low space utilization rate, as in the past. [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a battery pack that can maintain good rigidity even with a simplified structure when configuring a cell-to-pack battery pack, and that can simplify the process of mounting multiple battery cell assemblies into a pack case.

[0008] However, the technical problems that the present invention aims to solve are not limited to those described above, and other problems not mentioned can be clearly understood by an ordinary person of the art from the description of the invention below. [Means for solving the problem]

[0009] The present invention relates to a battery pack, in one example, comprising: a base plate; a front frame forming the front surface of the base plate; a rear frame forming the rear surface of the base plate; a pair of side frames whose ends are connected to the front frame and the rear frame; and a plurality of battery cell assemblies mounted in a housing space formed by the front frame, the rear frame, and the pair of side frames, wherein each of the battery cell assemblies comprises a battery cell unit including a plurality of cell stacks and a busbar frame assembly that is mechanically and electrically connected to the plurality of cell stacks at both lateral ends from which the leads of the cell stacks protrude; a first cell cross beam connected to the busbar frame assembly in front of the battery cell unit; and a second cell cross beam connected to the busbar frame assembly in rear of the battery cell unit, wherein the plurality of battery cell assemblies are fixed to the base plate with the first cell cross beam and the second cell cross beam, which face each other in the front-rear direction of adjacent battery cell assemblies, overlapping vertically.

[0010] In one embodiment, the first cell cross beam and the second cell cross beam may have a length corresponding to the distance between the pair of side frames.

[0011] Furthermore, the first cell crossbeam and the second cell crossbeam can be coupled to busbar frame assemblies provided in each of the multiple battery cell units.

[0012] The first cell cross beam has a protruding lower step, and the second cell cross beam has a protruding upper step. The first cell cross beam and the second cell cross beam can form a complementary configuration in which the upper step interlocks with the lower step and they overlap vertically.

[0013] The above-mentioned multiple battery cell assemblies can be fixed to the base plate by bolts that pass through the first and second cell cross beams, which are stacked vertically, and screw-connect to the base plate.

[0014] According to one embodiment of the present invention, the rear frame is provided with a lower projection corresponding to the lower step of the first cell cross beam, and the battery cell assembly closest to the rear frame can be fixed to the base plate with the upper step of the second cell cross beam overlapping the lower projection vertically.

[0015] Furthermore, the dummy crossbeam may be configured to correspond to the upper step of the second cell crossbeam, and the battery cell assembly closest to the front frame may be fixed to the base plate with the dummy crossbeam overlapping the lower step of the first cell crossbeam.

[0016] On the other hand, a battery pack according to one embodiment of the present invention includes a first step of preparing a pack case including a base plate, a front frame forming the front surface of the base plate, a rear frame forming the rear surface of the base plate, and a pair of side frames whose ends are connected to the front frame and the rear frame; a second step of preparing a battery cell assembly by preparing a first cell cross beam having a protruding lower step and a second cell cross beam having a complementary upper step that can overlap the lower step vertically, and fixing a battery cell unit between the first cell cross beam and the second cell cross beam which are arranged in parallel; and the first cell of the battery cell assembly It can be manufactured by a third step of fixing a battery cell assembly onto the base plate with the crossbeam and second cell crossbeam facing left and right of the pack case; a fourth step of preparing a new battery cell assembly via the second step and fixing the new battery cell assembly onto the base plate by securing it so that the upper step of the second crossbeam of the new battery cell assembly overlaps vertically with the lower step of the first cell crossbeam of the battery cell assembly fixed onto the base plate via the third step; and a fifth step of repeatedly performing the fourth step in the direction from the rear to the front of the pack case so as to fill all of the housing space of the pack case.

[0017] In the second step described above, the first cell cross beam and the second cell cross beam may have a length corresponding to the distance between the pair of side frames.

[0018] Furthermore, in the second step described above, multiple battery cell units can be fixed between the first cell cross beam and the second cell cross beam, which are arranged in parallel.

[0019] According to one embodiment, in the first step, the rear frame is provided with a lower projection corresponding to the lower step of the first cell cross beam, and in the third step, the battery cell assembly initially mounted in the pack case can be fixed to the base plate such that the upper step of the second cell cross beam overlaps the lower projection of the rear frame vertically.

[0020] In the fourth step described above, the new battery cell assembly can be fixed to the base plate by bolts that pass through the first and second cell cross beams, which are stacked vertically, and screw-connect to the base plate.

[0021] Then, in the fifth step described above, a dummy crossbeam is prepared in a form corresponding to the upper step of the second cell crossbeam, and the battery cell assembly that is to be mounted last in the pack case can be fixed to the base plate such that the dummy crossbeam overlaps the lower step of the first cell crossbeam vertically. [Effects of the Invention]

[0022] The battery pack of the present invention having the structure as described above has cell cross beams constituting the battery cell assembly overlapping vertically with the cell cross beams of other battery cell assemblies adjacent to each other inside the pack case. Thereby, the battery cell assembly can be fixed to the base plate using the load of other adjacent battery cell assemblies, and when the mounting of all the battery cell assemblies is completed, the fixed state is firmly maintained by the overlapping structure between the cell cross beams.

[0023] And by fixing a plurality of battery cell units to a pair of cell cross beams, the number of assembly steps of the battery pack is reduced and productivity is improved. By making the length of the cell cross beam correspond to the full width length of the pack case, the rigidity of the pack case can be maintained well without the configuration of the center beam, the number of parts is reduced, the battery pack can be lightened, and the space utilization rate is improved.

[0024] Also, by utilizing the structure in which the cell cross beams overlap between adjacent battery cell assemblies, the battery cell assembly can be fixed with bolts that are screwed to the base plate through the overlapping cell cross beams. Such bolt fixing can omit the welding process for the cross beam. By omitting the welding process, the productivity of the battery pack is improved, the interference problem caused by the welding beads is eliminated, and the space utilization rate is improved. [[ID=!0]]

[0025] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. Therefore, the present invention should not be construed as being limited only to the matters described in such drawings.

Brief Description of the Drawings

[0027] [Figure 1] A drawing showing a battery pack according to an embodiment of the present invention. [Figure 2] A drawing showing a state in which the frontmost battery cell assembly is separated from the battery pack of FIG. 1. [Figure 3] A perspective view of the battery cell assembly. [Figure 4] A drawing showing the battery cell assembly of FIG. 3 as viewed from the side. [Figure 5] A drawing showing the battery pack of FIG. 1 with the side frame removed and viewed from the side. [Figure 6] A cross-sectional view showing an enlarged view of the "A" portion of FIG. 5. [Figure 7] A cross-sectional view showing a structure in which the battery cell assembly is fixed to the rear frame. [Figure 8] A cross-sectional view showing a structure in which the foremost battery cell assembly is fixed to the base plate. [Figure 9] A drawing showing a state in which the battery cell assembly is first mounted in the pack case. [Figure 10] A drawing showing a state in which the battery cell assembly is next mounted in the pack case. [Figure 11] A drawing showing a state in which the battery cell assembly is finally mounted in the pack case.

Embodiments for Carrying Out the Invention

[0028] The present invention can be subjected to various modifications and can have various embodiments, so specific embodiments will be described in detail below.

[0029] However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents or alternatives included in the spirit and technical scope of the present invention.

[0030] In the present invention, terms such as "includes" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof as described in the specification, and do not preemptively exclude the presence or possibility of adding one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Furthermore, in this invention, when a part such as a layer, film, region, or plate is described as being "on top" of another part, this includes not only the case where it is "directly on top" of the other part, but also the case where another part is located in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "directly below" the other part, but also the case where another part is located in between. Also, in this application, being "on top" may include being located not only at the top but also at the bottom.

[0032] The present invention relates to a battery pack, and in one example includes a base plate, a front frame forming the front surface of the base plate, a rear frame forming the rear surface of the base plate, a pair of side frames whose ends are connected to the front frame and the rear frame, and a plurality of battery cell assemblies mounted in a housing space formed by the front frame, the rear frame, and the pair of side frames.

[0033] Here, each of the above-mentioned battery cell assemblies includes a battery cell unit comprising a plurality of cell stacks and a busbar frame assembly that is mechanically and electrically coupled to the plurality of cell stacks at both lateral ends where the leads of the cell stacks protrude, a first cell cross beam coupled to the busbar frame assembly in front of the battery cell unit, and a second cell cross beam coupled to the busbar frame assembly in rear of the battery cell unit.

[0034] The above-mentioned multiple battery cell assemblies are fixed to the base plate with the first cell cross beam and the second cell cross beam, which face each other in the front-to-back direction of adjacent battery cell assemblies, overlapping each other vertically.

[0035] For example, the multiple battery cell assemblies described above can be fixed to the base plate by bolts that pass through the first and second cell cross beams, which are stacked vertically, and screw-connected to the base plate.

[0036] In the battery pack of the present invention having such a structure, the cell cross beams constituting the battery cell assembly overlap vertically with the cell cross beams of other adjacent battery cell assemblies inside the pack case. This allows the battery cell assembly to be fixed to the base plate using the load of the adjacent battery cell assemblies, and once all battery cell assemblies have been mounted, the overlapping structure between the cell cross beams firmly maintains the fixed state.

[0037] Furthermore, by utilizing the structure in which cell crossbeams overlap between adjacent battery cell assemblies, the battery cell assemblies can be fixed with bolts that penetrate the overlapping cell crossbeams and screw-connect to the base plate. Such bolt fixing eliminates the welding process to the crossbeams, improving the productivity of the battery pack, eliminating interference problems caused by weld beads, and improving space utilization.

[0038] Hereinafter, specific embodiments of the battery pack 10 according to the present invention will be described in detail with reference to the attached drawings. For reference, the forward / backward and up / down / left / right directions used in the following description to specify relative positions are for the purpose of aiding the understanding of the invention, and unless otherwise defined, the directions shown in the drawings shall be used as the reference.

[0039] (First Embodiment) Figure 1 is a drawing showing a battery pack 10 according to one embodiment of the present invention, Figure 2 is a drawing showing the battery pack 10 of Figure 1 with the frontmost battery cell assembly 202 separated, and Figure 3 is a perspective view of the battery cell assembly 200. The battery pack 10 according to the present invention will be described in detail with reference to the attached drawings.

[0040] The battery pack 10 of the present invention includes a pack case 100 and a plurality of battery cell assemblies 200. The pack case 100 includes a base plate 110, a front frame 120 that forms the front surface of the base plate 110, a rear frame 130 that forms the rear surface of the base plate 110, and a pair of side frames 140 whose ends are connected to the front frame 120 and the rear frame 130. The frame surrounding the outer casing of the base plate 110 forms a housing space for mounting the plurality of battery cell assemblies 200. For reference, the drawings omit the lead (lid) that covers the top surface of the pack case 100 to seal the housing space in order to show the internal structure of the battery pack 10.

[0041] The drawing also displays front, rear, left, and right (FRLR) symbols, which are based on the directions shown in the drawing. These front, rear, left, and right directions are based on the drawing for the sake of explanation and to avoid confusion, and may not correspond to the directions actually used to refer to the battery pack 10 in the field. In the following explanation, we will continue to use the front, rear, left, and right directions based on the drawing.

[0042] According to the illustrated embodiment, the battery cell assembly 200 includes a battery cell unit 210 comprising a plurality of cell stacks 212 and a busbar frame assembly 214 that is mechanically and electrically coupled to the plurality of cell stacks 212 at both lateral ends where the leads of the cell stacks 212 protrude.

[0043] In this specification, a secondary battery having multiple positive and negative electrodes stacked with a separator membrane in between, and having leads that electrically connect the electrode tabs on the positive and negative electrodes, is referred to as a cell stack 212. That is, a cell stack 212 refers to a single completed secondary battery that can be repeatedly charged and discharged, and is not limited to a specific form such as a pouch-type battery or a prismatic battery. A battery cell unit 210 corresponds to the concept of a module formed by assembling multiple such cell stacks 212, and a bundle of cell stacks 212 is mechanically constrained and electrically connected by busbar frame assemblies 214 at both the front and rear ends.

[0044] The battery cell assembly 200 includes a first cell crossbeam 220 that connects to the busbar frame assembly 214 at the front of the battery cell unit 210, and a second cell crossbeam 230 that connects to the busbar frame assembly 214 at the rear of the battery cell unit 210. The first cell crossbeam 220 and the second cell crossbeam 230 are frames that maintain the structure of the battery cell assembly 200, and at the same time, when the battery cell assembly 200 is mounted in the pack case 100, they play the role of crossbeams that provide rigidity to the pack case 100 in the left-right direction, i.e., in the width direction or lateral direction.

[0045] Here, the first cell cross beam 220 and the second cell cross beam 230 are referred to as such because, although they function as cross beams on the side of the pack case 100, considering the assembly process, they are initially assembled in the form of a battery cell assembly 200 as a frame for fixing the battery cell unit 210. Therefore, they are called cell cross beams to distinguish them from pack cross beams. Furthermore, the terms "first~" and "second~" are used to distinguish these two cell cross beams 220 and 230 within a pair because their form differs depending on whether the first cell cross beam 220 or the second cell cross beam 230 is mounted facing forward or backward. This will be explained above with reference to the drawings.

[0046] In the battery pack 10 of the present invention, a plurality of battery cell assemblies 200 are mounted on a base plate 110, and the first cell cross beam 220 and the second cell cross beam 230 of adjacent battery cell assemblies 200, which face each other in the front-to-back direction, are fixed to the base plate 110 in an overlapping state. In other words, each battery cell assembly 200 has the same structure, and all battery cell assemblies 200 are mounted on the pack case 100 with the first cell cross beam 220 and the second cell cross beam 230 facing left-to-right, so that the first cell cross beam 220 and the second cell cross beam 230 of adjacent battery cell assemblies 200 face each other in close proximity.

[0047] This repeated facing structure of the first cell cross beam 220 and the second cell cross beam 230 allows adjacent battery cell assemblies 200 to have the first cell cross beam 220 and the second cell cross beam 230 overlapping vertically. By fixing the overlapping first cell cross beam 220 and the second cell cross beam 230 together to the base plate 110, the facing front and rear edges of adjacent battery cell assemblies 200 can be fixed to the base plate 110 simultaneously.

[0048] In one embodiment, the first cell crossbeam 220 and the second cell crossbeam 230 may have a length corresponding to the distance between a pair of side frames 140, i.e., the overall width of the pack case 100. As a result, even without the configuration of a center beam provided in conventional battery packs, the pack case 100 of the present invention can maintain good lateral rigidity by having a structure in which the crossbeams traverse without any interruptions in the left-right direction.

[0049] Furthermore, busbar frame assemblies 214 provided on each of the multiple battery cell units 210 can be coupled to a pair of first cell cross beams 220 and second cell cross beams 230. That is, multiple battery cell assemblies 200 can be fixed to the pair of first cell cross beams 220 and second cell cross beams 230 by bolts or the like. By fixing multiple battery cell assemblies 200 to the pair of first cell cross beams 220 and second cell cross beams 230 in this way, the number of steps required to mount the battery cell assemblies 200 to the pack case 100 is reduced.

[0050] Taking the illustrated embodiment as an example, when mounting a total of six battery cell assemblies 200 onto the pack case 100, if one battery cell assembly 200 is fixed to a pair of cell cross beams 220 and 230, a total of six mounting steps would be required. However, by fixing two battery cell assemblies 200 to a pair of cell cross beams 220 and 230, the work can be completed in just three mounting steps. Therefore, by making the first cell cross beam 220 and the second cell cross beam 230 the same length as the total width of the pack case 100 and fixing multiple battery cell assemblies 200 to them, not only the rigidity of the pack case 100 but also the productivity of the battery pack 10 can be improved.

[0051] Figure 4 is a side view of the battery cell assembly 200 shown in Figure 3. In the embodiments of the present invention, all battery cell assemblies 200 have the same structure. Referring to Figures 3 and 4, the first cell cross beam 220 has a protruding lower step 222, and the second cell cross beam 230 has a protruding upper step 232. The first cell cross beam 220 and the second cell cross beam 230 have a complementary configuration in which the upper step 232 interlocks with the lower step 222 and they overlap vertically. That is, they have a superimposed structure in which the upper step 232 of the second cell cross beam 230 can interlock with the lower step 222 of the first cell cross beam 220, and the overlapping first cell cross beam 220 and the second cell cross beam 230 function as a single pack cross beam.

[0052] Figure 5 is a side view of the battery pack 10 from Figure 1 with the side frame 140 removed, showing the connecting structure between adjacent battery cell assemblies 200. Using the drawing as a reference, an overlapping structure can be observed in which the upper step 232 of the second cell cross beam 230 of the left battery cell assembly 200 rests on the lower step 222 of the first cell cross beam 220 of the right battery cell assembly 200, and this overlapping structure is repeated at the front and rear edges of the battery cell assemblies 200.

[0053] Figure 6 is a cross-sectional view showing an enlarged view of section "A" in Figure 5. Multiple battery cell assemblies 200 are fixed to the base plate 110 by bolts 240 that pass through the vertically overlapping first cell cross beams 220 and second cell cross beams 230 and screw-connect to the base plate 110. In other words, the battery pack 10 of the present invention utilizes a structure in which cell cross beams overlap between adjacent battery cell assemblies 200, and can fix the battery cell assemblies 200 with bolts 240 that pass through the overlapping cell cross beams and screw-connect to the base plate 110. Fixing with such bolts 240 eliminates the need for the conventional welding process to the cross beams, improving the productivity of the battery pack 10 by eliminating the welding process and improving space utilization by eliminating interference problems between the battery cell assemblies 200 due to weld beads.

[0054] Figures 5 and 6 show the coupling structure between adjacent battery cell assemblies 200. However, the battery cell assemblies 201 and 202 located at the rearmost and frontmost positions of the battery pack 10 do not have adjacent battery cell assemblies 200 behind and in front of them, respectively. Therefore, a separate structure is required to complete the fixing of the rearmost and frontmost battery cell assemblies 201 and 202 to the base plate 110.

[0055] Figure 7 is a cross-sectional view showing a structure in which the battery cell assembly 200 is fixed to the rear frame 130. The rear frame 130 has a lower projection 132 corresponding to the lower step 222 of the first cell cross beam 220. As a result, the battery cell assembly 200 closest to the rear frame 130, i.e., the rearmost battery cell assembly 201, can be fixed to the base plate 110 by having the upper step 232 of the second cell cross beam 230 overlap vertically with the lower projection 132 of the rear frame 130. Such a lower projection 132 of the rear frame 130 not only provides an efficient structure for fixing the rearmost battery cell assembly 201 to the base plate 110, but also contributes to increasing the rigidity of the pack case 100 as the cross-sectional area increases with the size of the lower projection 132.

[0056] Figure 8 is a cross-sectional view showing the structure in which the foremost battery cell assembly 202 is fixed to the base plate 110. The pack case 100 requires space for installing a venting device or for arranging various mechanisms for electrical connection, but in the pack case 100 according to one embodiment of the present invention, such service space is located on the front frame 120 side. Therefore, the foremost battery cell assembly 202 is fixed to the base plate 110 using a dummy crossbeam 250 in a form corresponding to the upper step 232 of the second cell crossbeam 230, rather than being fixed to the base plate 110 via the front frame 120, as is the case with the rearmost battery cell assembly 201. Referring to Figure 8, the battery cell assembly 202 closest to the front frame 120 has the dummy crossbeam 250 overlapping the lower step 222 of the first cell crossbeam 220 with the dummy crossbeam 250 approaching upward, and bolts 240 passing through the dummy crossbeam 250 and the first cell crossbeam 220 are screw-connected to the base plate 110.

[0057] Thus, in the battery pack 10 of the present invention, the cell cross beams constituting the battery cell assembly 200 overlap vertically with the cell cross beams of other adjacent battery cell assemblies 200 inside the pack case 100. This allows the battery cell assembly 200 to be fixed to the base plate 110 using the load of the adjacent battery cell assemblies 200, and once all battery cell assemblies 200 have been mounted, the overlapping structure between the cell cross beams firmly maintains the fixed state.

[0058] Furthermore, by utilizing the structure in which the cell cross beams overlap between adjacent battery cell assemblies 200, the battery cell assemblies 200 are fixed with bolts 240 that penetrate the overlapping cell cross beams and are screw-connected to the base plate 110. This type of bolt 240 fixing eliminates the need for a welding process to the cross beams.

[0059] (Second Embodiment) Figures 9 to 11 are diagrams showing a series of manufacturing processes for a battery pack 10 according to one embodiment of the present invention. In the following description, content that overlaps with the configuration of the battery pack 10 described in the first embodiment will be omitted.

[0060] Figure 9 is a diagram showing the state in which the battery cell assembly 200 is initially mounted in the pack case 100. The manufacturing method of the battery pack 10 according to the present invention includes a first step of preparing a pack case 100 which includes a base plate 110, a front frame 120 that forms the front surface of the base plate 110, a rear frame 130 that forms the rear surface of the base plate 110, and a pair of side frames 140 whose ends are connected to the front frame 120 and the rear frame 130.

[0061] Next, a second step is performed in which a first cell cross beam 220 having a protruding lower step 222 and a second cell cross beam 230 having a complementary upper step 232 that can overlap the lower step 222 vertically are prepared, and a battery cell unit 210 is fixed between the first cell cross beam 220 and the second cell cross beam 230 which are arranged in parallel to each other to prepare a battery cell assembly 200.

[0062] In the second step, the first cell cross beam 220 and the second cell cross beam 230 may have a length corresponding to the distance between a pair of side frames 140, and furthermore, multiple battery cell units 210 can be fixed between the first cell cross beam 220 and the second cell cross beam 230 which are arranged in parallel.

[0063] Here, the first step is to prepare the pack case 100, and the second step is to prepare the battery cell assembly 200. These preparation steps may be performed in an integrated or separate process, and their order in time may vary.

[0064] The third step is to mount the battery cell assembly 200 onto the pack case 100, in which the battery cell assembly 200 is fixed onto the base plate 110 with the first cell cross beam 220 and the second cell cross beam 230 of the battery cell assembly 200 facing left and right on the pack case 100. At this time, the first battery cell assembly 200 to be mounted is the rearmost battery cell assembly 201, which is close to the rear frame 130.

[0065] To improve the mounting efficiency of the rearmost battery cell assembly 201 and increase the rigidity of the pack case 100, the rear frame 130 of the pack case 100 prepared in the first step may be provided with a lower projection 132 corresponding to the lower step 222 of the first cell cross beam 220. Thus, the third step may be performed in which the battery cell assembly 200 initially mounted in the pack case 100 is fixed to the base plate 110 such that the upper step 232 of the second cell cross beam 230 overlaps vertically with the lower projection 132 of the rear frame 130.

[0066] Figure 10 is a diagram showing the state in which the battery cell assembly 200 is then mounted on the pack case 100. The fourth step is to secure the new battery cell assembly 200 to the base plate 110 by fixing the new battery cell assembly 200 so that the upper step 232 of the second cross beam of the new battery cell assembly 200 overlaps the lower step 222 of the first cell cross beam 220 of the battery cell assembly 200 that was fixed to the base plate 110 via the third step.

[0067] When fixing the battery cell assembly 200 to the base plate 110 in this manner, as shown in Figures 6 and 7, the new battery cell assembly 200 can be fixed to the base plate 110 by bolts 240 that pass through the upper and lower overlapping first cell cross beams 220 and second cell cross beams 230 and screw-connect to the base plate 110, as well as the second cell cross beam 230 of the battery cell assembly 200 which is fixed to the base plate 110 together with the rear frame 130.

[0068] This fourth step is repeated in the fifth step along the rear-to-front direction of the pack case 100 until the battery cell assemblies 200 fill all the housing space of the pack case 100. In the illustrated embodiment, a total of three rows of battery cell assemblies 200 are installed, so the installation of the battery cell assemblies 200 in the fourth step is repeated once more, with the last battery cell assembly 200 to be installed being the frontmost battery cell assembly 202.

[0069] Figure 11 shows the state in which the battery cell assembly 202 is finally mounted in the pack case 100. In the fifth step, a dummy crossbeam 250 is prepared in a form corresponding to the upper step 232 of the second cell crossbeam 230, and the battery cell assembly 202, which is finally mounted in the pack case 100, is fixed to the base plate 110 such that the dummy crossbeam 250 overlaps the lower step 222 of the first cell crossbeam 220 vertically. The structure of the battery pack 10 corresponding to this can be seen in Figure 8.

[0070] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, at the time of filing, there may be various equivalents and modifications that can substitute for them. [Explanation of symbols]

[0071] 10: Battery Pack 100: Pack Case 110: Base plate 120: Front frame 130: Rear frame 132: Lower protrusion 140: Side frame 200: Battery cell assembly 201: Rearmost battery cell assembly 202: Forward battery cell assembly 210: Battery cell unit 212: Cell laminate 214: Busbar Frame Assembly 220: First cell crossbeam 222: Lower step 230: Second cell crossbeam 232: Upper step 240: Bolt 250: Dummy Crossbeam

Claims

1. base plate and The front frame forming the front surface of the base plate, A rear frame forming the rear surface of the base plate, A pair of side frames, whose ends are connected to the front frame and rear frame, Includes a plurality of battery cell assemblies mounted within a housing space formed by the front frame, rear frame, and a pair of side frames, Each of the aforementioned battery cell assemblies is: A battery cell unit comprising a plurality of cell stacks and a busbar frame assembly that mechanically and electrically connects to the plurality of cell stacks at both lateral ends where the leads of the cell stacks protrude, A first cell cross beam coupled to the busbar frame assembly at the front of the battery cell unit, Includes a second cell crossbeam coupled to the busbar frame assembly at the rear of the battery cell unit, In a battery pack in which the plurality of battery cell assemblies are fixed to the base plate with a first cell cross beam and a second cell cross beam that face each other in the front-rear direction of adjacent battery cell assemblies overlapping vertically, The first cell cross beam has a protruding lower step, The second cell cross beam has a protruding upper step, The first cell cross beam and the second cell cross beam have a complementary configuration in which the upper step interlocks with the lower step and they overlap vertically. The aforementioned plurality of battery cell assemblies are The first cell cross beam and the second cell cross beam, which are stacked vertically, are fixed to the base plate by bolts that pass through them and are screw-connected to the base plate. A battery pack in which the lower step and the upper step are configured to be connected or separated along the vertical direction.

2. The first cell cross beam and the second cell cross beam are The battery pack according to claim 1, having a length corresponding to the distance between the pair of side frames.

3. The first cell cross beam and the second cell cross beam are The battery pack according to claim 2, wherein each of the multiple battery cell units is coupled to a busbar frame assembly provided on each of them.

4. The rear frame is provided with a lower projection corresponding to the lower step of the first cell cross beam, The battery pack according to claim 1, wherein the battery cell assembly closest to the rear frame has the upper step of the second cell cross beam overlapping the lower protrusion vertically and is fixed to the base plate.

5. The invention further includes a dummy crossbeam in a form corresponding to the upper step of the second cell crossbeam, The battery pack according to claim 1, wherein the battery cell assembly closest to the front frame has the dummy crossbeam overlapping the lower step of the first cell crossbeam vertically and is fixed to the base plate.

6. A first step of preparing a pack case including a base plate, a front frame forming the front surface of the base plate, a rear frame forming the rear surface of the base plate, and a pair of side frames whose ends are connected to the front frame and the rear frame, The second step of preparing a battery cell assembly is to prepare a first cell cross beam having a protruding lower step and a second cell cross beam having a complementary upper step that overlaps the lower step vertically, and to fix a battery cell unit between the first cell cross beam and the second cell cross beam which are arranged in parallel, A third step involves fixing the battery cell assembly onto the base plate with the first cell cross beam and the second cell cross beam of the battery cell assembly facing left and right in the pack case, A fourth step involves preparing a new battery cell assembly via the second step, and fixing the new battery cell assembly to the base plate via the third step by securing it so that the upper step of the second cross beam of the new battery cell assembly overlaps the lower step of the first cell cross beam of the battery cell assembly fixed to the base plate via the third step, A method for manufacturing a battery pack, comprising a fifth step of repeatedly performing the fourth step in the direction from the rear to the front of the pack case so as to fill all of the storage space of the pack case, In the first step described above, The rear frame is provided with a lower projection corresponding to the lower step of the first cell cross beam, In step 3, The battery cell assembly initially mounted in the pack case is fixed to the base plate such that the upper step of the second cell crossbeam overlaps vertically with the lower protrusion of the rear frame. In the fourth step described above, A method for manufacturing a battery pack, wherein the new battery cell assembly is fixed to the base plate by bolts that pass through the first and second cell cross beams, which are stacked vertically, and screw-connected to the base plate.

7. In the second step described above, The method for manufacturing a battery pack according to claim 6, wherein the first cell cross beam and the second cell cross beam have a length corresponding to the distance between the pair of side frames.

8. In the second step described above, A method for manufacturing a battery pack according to claim 7, wherein a plurality of battery cell units are fixed between the first cell cross beam and the second cell cross beam, which are arranged in parallel.

9. In the fifth step described above, A dummy crossbeam is prepared in a form corresponding to the upper step of the second cell crossbeam. The method for manufacturing a battery pack according to claim 6, wherein the battery cell assembly to be last mounted in the pack case is fixed to the base plate such that the dummy crossbeam overlaps the lower step of the first cell crossbeam vertically.

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