Battery pack

Abstract

In one example, the pack case includes a base plate, side plates connected along the edges of the base plate to form a storage space therein, a lower cross beam connected to the base plate so as to horizontally divide the storage space inside the base plate, and an upper cross beam connected to the lower cross beam, wherein the lower cross beam and the upper cross beam each have a binding groove that regulates the installation position of the cell stack.

Description

[Technical field]

[0001] The present invention relates to a battery pack, and more particularly to a battery pack having a structure in which a cell stack or a battery module is closely attached to a partition wall without interference from a weld bead and the mounting position can be controlled. In particular, the present invention provides a battery pack suitable for a cell to pack (CTP) structure in which a cell stack is directly installed in the battery pack.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167142 dated December 2, 2022, and Korean Patent Application No. 10-2023-0035421 dated March 17, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0003] Conventionally, a battery pack has been manufactured by accommodating a plurality of battery modules, each of which has a plurality of cell stacks accommodated in a module housing, in a pack case.

[0004] However, in such a conventional battery pack, the manufacturing cost increases and the cooling performance decreases because thermal resin is applied twice, between the cell stack and the module housing and between the module housing and the pack case. In addition, additional parts are required for mounting the module parts and the pack case to configure the battery module, which increases the parts cost. In addition, when welding the partition wall that divides the battery module to the pack case, the weld bead generated on the partition wall makes it impossible to install the module housing in close contact with the partition wall, which reduces the space utilization rate of the pack case and reduces the energy density of the battery pack.

[0005] Even in a simplified structure in which a cell stack is directly mounted on a pack case by removing a module housing to realize a battery pack with a cell-to-pack structure, the problem of interference with the cell stack due to weld beads of the bulkheads still remains. In addition, even though the cell stack is directly mounted on the pack case, it is necessary to regulate the initial installation position of the cell stack so that it is not disturbed not only at the time of installation but also during long-term use of the battery pack, but in a simplified cell-to-pack structure in which the module housing is removed, it is difficult to regulate the position of the cell stack.

[0006] Furthermore, when installing a cell stack between partition walls without a module housing, it is very advantageous in terms of productivity to use a loading jig that grasps and inserts a number of cell stacks into the partition walls at once. However, it has been difficult to install a large number of cell stacks in a pack case at once due to interference between the partition walls and the loading jig, which grasps the cell stacks deeply in order to stably transport a heavy group of cell stacks.

[0007] Therefore, there is a demand for the development of technology that can simplify the structure of a battery pack, improve space utilization rate and energy density by eliminating interference from weld beads, control the position of cell stacks even in a cell-to-pack structure without a module housing, and effectively install a large number of cell stacks in a pack case. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a pack case in which welding work for joining a cross beam to a base plate can be easily performed, uniform surface pressure can be applied to a plurality of cell stacks, and a loading jig that handles a large number of cell stacks as a single unit can perform work stably without interference from the cross beam.

[0009] Another object of the present invention is to provide a pack case that can solve the problem of interference with the cell stack caused by weld beads that inevitably occur when welding a cross beam to a base plate.

[0010] Another object of the present invention is to provide a pack case having a simplified configuration, for example, a pack case capable of regulating the position of a cell stack even in a cell-to-pack structure without a separate module housing.

[0011] However, the technical problem that the present invention aims to solve is not limited to the above-mentioned problem, and other problems not mentioned can be clearly understood by a person skilled in the art from the description of the invention described below. [Means for solving the problem]

[0012] The present invention relates to a pack case, and in one example, includes a base plate, a side plate connected along the edge of the base plate to form a storage space inside the base plate, a lower cross beam connected to the base plate so as to horizontally divide the storage space inside the base plate, and an upper cross beam connected to the lower cross beam, wherein the lower cross beam and the upper cross beam are each provided with a binding groove that regulates the installation position of a cell stack.

[0013] In the pack case of the present invention, the upper cross beam is joined upwardly to the lower cross beam to form one cross beam.

[0014] In one embodiment, the lower cross beam may have a first uneven structure in which recesses and protrusions are repeated in the joining direction of the upper cross beam, and the upper cross beam may have a second uneven structure that is complementary to the first uneven structure.

[0015] The lower cross beam may be welded to the base plate and the upper cross beam may be bolted to the lower cross beam.

[0016] In one embodiment, the lower cross beam and the upper cross beam are made of dissimilar materials, and the upper cross beam may be made of a lighter weight material than the lower cross beam.

[0017] Meanwhile, the lower cross beam may include at least one recessed weld groove on its interface with the base plate.

[0018] For example, the weld grooves may be provided on both sides of the lower cross beam.

[0019] The weld grooves provided on both sides of the lower cross beam may be arranged in a distributed manner so as not to overlap at least a portion of each other along the direction in which they face each other.

[0020] The lower cross beam is welded to the base plate through the weld groove, and a weld bead formed in the weld groove may not protrude outside the lower cross beam.

[0021] In one embodiment of the present invention, the binding groove may be formed in the form of an open groove having an opening at the joining surface between the lower cross beam and the upper cross beam.

[0022] In another embodiment of the present invention, the binding groove may be formed in the form of a hole separated from each other by the joining surface of the lower cross beam and the upper cross beam, and may include a guide groove connected from the joining surface of the lower cross beam and the upper cross beam to the hole.

[0023] Meanwhile, the present invention may provide a battery pack including a pack case having the above-described configuration, and a plurality of cell stacks mounted in divided accommodation spaces of the pack case.

[0024] The plurality of cell stacks may include a bus bar frame assembly coupled to the battery cell stack at both ends from which the leads protrude, and the bus bar frame assembly may have protrusion structures fastened to respective binding grooves of the lower cross beam and the upper cross beam.

[0025] In one embodiment, the binding groove is formed in the form of an open groove with an opening at the joining surface between the lower cross beam and the upper cross beam, and correspondingly, the protrusion structure can be provided as a fin structure corresponding to a form in which the open grooves of the lower cross beam and the upper cross beam are connected into one.

[0026] In another embodiment, the binding groove is formed in the form of a hole separated from each other by the joining surfaces of the lower cross beam and the upper cross beam, and correspondingly, the protrusion structure can be provided as a snap-fit ​​joint including a cantilever lug fastened to the holes in the lower cross beam and the upper cross beam.

[0027] The binding groove includes a guide groove connecting the joining surface of the lower cross beam and the upper cross beam to the hole, and the protrusion structure can be fastened to the hole by the cantilever lug sliding over the surface of the guide groove.

[0028] The protruding structures may be disposed on both sides of the busbar frame assembly opposite the respective binding grooves of the lower cross beam and the upper cross beam.

[0029] And, the bus bar frame assembly may include an insulating cover coupled to a front surface thereof.

[0030] A thermal resin may be interposed between the contact surfaces of the plurality of cell stacks and the base plate. Effect of the Invention

[0031] As described above, the pack case of the present invention has a two-layer structure in which one cross beam is connected to a base plate, and an upper cross beam is connected above the lower cross beam. The two-layer cross beam structure improves the accessibility of the welding tool tip, facilitating the welding operation of the lower cross beam to the base plate, and improves the operability of the loading jig by seating multiple cell stacks in the pack case before assembling the upper cross beam.

[0032] Furthermore, by constructing the cross beam with a two-layer structure, the upper cross beam, which does not require welding to the base plate, can be made of a lightweight dissimilar material, such as engineering plastic, which can contribute to reducing the weight of the battery pack.

[0033] In addition, the pack case of the present invention has binding grooves in each of the lower cross beam and the upper cross beam that regulate the installation position of the cell stack. This makes it possible to regulate the position of the cell stack even in a pack case structure with a simplified configuration, for example, a cell-to-pack structure without a separate module housing, thereby improving the productivity and safety of the battery pack.

[0034] In addition, according to one embodiment of the present invention, the lower cross beam is provided with a first uneven structure, so that the gripper of the loading jig can firmly grasp and enter the cell stack without interfering with the lower cross beam, and the cell stack can be placed stably on the base plate without impact.

[0035] 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 of ordinary skill in the art from the description of the invention described below.

[0036] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. [Brief description of the drawings]

[0037] [Figure 1] FIG. 2 is a perspective view of a pack case according to one embodiment of the present invention. [Diagram 2] 2 is a perspective view showing a state in which an upper cross beam is separated from the pack case of FIG. 1. FIG. [Diagram 3] 1 is a view showing a coupling structure between a lower cross beam and an upper cross beam; [Figure 4] FIG. 4 is a cross-sectional view taken along line "AA" in FIG. [Diagram 5] FIG. 4 is a perspective view showing a welded structure of a lower cross beam to a base plate. [Figure 6] FIG. 13 is a plan view showing the weld points of the lower cross beam to the base plate. [Figure 7] 1 illustrates an embodiment of a cross beam with bundling grooves. [Figure 8] 13 is a view showing another embodiment of a cross beam having a binding groove. [Figure 9] 8 is a diagram showing a configuration in which a plurality of cell stacks are mounted on a pack case including the cross beam of FIG. 7. [Figure 10] 8 is an enlarged view showing a structure in which a protrusion structure of a bus bar frame assembly is coupled to a binding groove of FIG. 7; [Figure 11] 9 is an enlarged view showing a structure in which a protrusion structure of a bus bar frame assembly is coupled to a binding groove of FIG. 8 . [Figure 12] 1 is a perspective view of a battery pack according to an embodiment of the present invention; [Figure 13] FIG. 13 is a cross-sectional view taken along line "BB" in FIG. 12. [Diagram 41]FIG. 13 is a perspective view showing an embodiment in which a gripper of a loading jig holding a plurality of cell stacks enters a lower cross beam. [Figure 15] 15 is a cross-sectional view showing a state in which the loading jig of FIG. 14 has entered a lower cross beam. FIG. [Figure 16] 11A to 11C are cross-sectional views showing a process of removing the loading jig after a plurality of cell stacks are seated. [Figure 17] 13 is a cross-sectional view showing a state in which the upper cross beam is fastened after the loading jig is detached. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0039] However, this is not intended to limit the invention to any particular embodiment, but it should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0040] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and may be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0041] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0042] The present invention relates to a pack case, which in one example includes a base plate, side plates connected along the edges of the base plate to form a storage space therein, a lower cross beam connected to the base plate so as to horizontally divide the storage space inside the base plate, and an upper cross beam connected to the lower cross beam, wherein the lower cross beam and the upper cross beam are each provided with binding grooves that regulate the installation position of a cell stack.

[0043] In the pack case of the present invention, the upper cross beam is joined upwardly to the lower cross beam to form one cross beam.

[0044] In this way, the pack case of the present invention has a two-layer structure with one cross beam being a lower cross beam connected to the base plate and an upper cross beam connected above the lower cross beam. The two-layer cross beam structure improves the accessibility of the welding tool tip, facilitating the welding operation of the lower cross beam to the base plate, and improves the operability of the loading jig by seating multiple cell stacks in the pack case before assembling the upper cross beam.

[0045] Furthermore, by constructing the cross beam with a two-layer structure, the upper cross beam, which does not require welding to the base plate, can be made of a lightweight dissimilar material, such as engineering plastic, which can contribute to reducing the weight of the battery pack.

[0046] In particular, the pack case of the present invention has binding grooves in each of the lower cross beam and the upper cross beam that regulate the installation position of the cell stack. This makes it possible to regulate the position of the cell stack even in a cell-to-pack structure that does not have a separate module housing, thereby improving the productivity and safety of the battery pack.

[0047] Hereinafter, specific embodiments of the pack case 100 according to the present invention and the battery pack 200 including the same will be described in detail with reference to the accompanying drawings. For reference, the directions of front / back, up / down, left / right, and the like that specify relative positions used in the following description are intended to aid in understanding the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0048] (First embodiment) FIG. 1 is an oblique view of a pack case 100 according to one embodiment of the present invention, and FIG. 2 is an oblique view showing the pack case 100 of FIG. 1 with an upper cross beam 136 separated. The overall configuration of the pack case 100 according to one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[0049] The present invention relates to a pack case 100 that houses a number of equally divided cell stacks 210. The cell stack 210 is a completed battery cell that can be charged and discharged as a secondary battery, and in this specification, the term is used in a comprehensive sense regardless of the external shape of the cell stack, such as a pouch-type battery or a square-type battery. In addition, it is not excluded that a battery module in which a number of cell stacks 210 are housed in one housing is constructed and mounted in the pack case 100. However, in particular, considering that the pack case 100 of the present invention is suitable for a cell-to-pack structure that does not use various module components such as a module housing, the number of cell stacks 210 are shown in the drawings as a simple collection of pouch-type batteries.

[0050] The illustrated pack case 100 includes a base plate 110 and a side plate 120 that is coupled along the edge of the base plate 110 and forms an accommodation space therein. A cross beam 130 that is coupled to the base plate 110 in the lateral direction with respect to the drawing and serves as a partition member that divides the accommodation space inside the base plate 110. In the illustrated embodiment, the cross beam 130 of the pack case 100 has a length that corresponds to the lateral width of the base plate 110, so that both ends of the cross beam 130 contact or adjoin the side plate 120.

[0051] 2, the cross beam 130 is composed of a lower cross beam 132 that is directly connected to the base plate 110 so as to laterally divide the storage space inside the base plate 110, and an upper cross beam 136 that is connected to the lower cross beam 132. The upper cross beam 136 is connected upward to the lower cross beam 132, that is, the upper cross beam 136 is connected to the lower cross beam 132 in an aligned state so as to overlap from above the lower cross beam 132, forming a double-layer structure.

[0052] In this way, by forming a two-layer structure in which one cross beam 130 is divided into the lower cross beam 132 and the upper cross beam 136, the pack case 100 of the present invention has many advantages. For example, since only the lower cross beam 132 needs to be joined to the base plate 110, the height of the cross beam 130 is reduced, improving the accessibility of a welding tool tip and facilitating welding work on the lower cross beam 132. Furthermore, since a plurality of cell stacks 210 can be loaded into the pack case 100 before assembling the upper cross beam 136, problems with interference with the cross beam 130 are reduced, improving the operability of the loading jig 300 that handles a plurality of cell stacks 210 at once.

[0053] In addition, by constructing the cross beam 130 in a two-layer structure, the upper cross beam 136, which does not require welding to the base plate 110, can be made of a lightweight dissimilar material; for example, the lower cross beam 132 can be made of a metal material such as stainless steel that can be welded, and the upper cross beam 136 can be made of an even lighter engineering plastic, etc., which can contribute to reducing the weight of the battery pack 200.

[0054] Fig. 3 is a diagram showing one embodiment of a coupling structure of the lower cross beam 132 and the upper cross beam 136, and Fig. 4 is a cross-sectional view taken along line "AA" in Fig. 3. According to the illustrated embodiment, the lower cross beam 132 has a first uneven structure 133 in which recesses 133-1 and protrusions 133-2 are repeated in the upward coupling direction of the upper cross beam 136, and correspondingly, the upper cross beam 136 has a second uneven structure 137 having a shape complementary to the first uneven structure 133.

[0055] Here, the first uneven structure 133 and the second uneven structure 137 have a complementary shape, which means that the recess 133-1 of the first uneven structure 133 and the protrusion 137-2 of the second uneven structure 137, and the protrusion 133-2 of the first uneven structure 133 and the recess 137-1 of the second uneven structure 137 face each other to form a kind of meshing structure. The complementary first uneven structure 133 and the second uneven structure 137 determine a single joining position of the upper cross beam 136 to the lower cross beam 132, so that the lower cross beam 132 and the upper cross beam 136 are accurately aligned, which makes it easy to complete the fastening operation with the bolts 138 in a provisionally assembled state of the lower cross beam 132 and the upper cross beam 136. In addition, as described later, the first uneven structure 133 of the lower cross beam 132 is also advantageously used to avoid interference with the loading jig 300.

[0056] As described above, the lower cross beam 132 may be connected to the base plate 110 by welding, and the upper cross beam 136 may be connected to the lower cross beam 132 by bolts 138. This separated two-layer connection structure allows the upper cross beam 136 to be made of a lightweight dissimilar material. Referring to FIG. 3, when considering the effective screw fastening depth of the bolts 138, it is advantageous to have a short approach path from the upper cross beam 136 to the lower cross beam 132, so that the bolts 138 are fastened in the region where the recesses 137-1 of the second concave-convex structure 137 are joined to the protrusions of the first concave-convex structure 133.

[0057] 4, the lower cross beam 132 and the upper cross beam 136 are basically hollow and have a rib structure connecting both side walls to reinforce rigidity. The hollow structure of the lower cross beam 132 and the upper cross beam 136 can reduce weight, and also advantageously slows down heat propagation due to thermal runaway by preventing heat generated in one cell stack 210 in the pack case 100 from transferring in the form of conduction to another cell stack 210 between which the cross beam 130 is placed.

[0058] Second embodiment FIG. 5 is a perspective view showing the welded structure of the lower cross beam 132 to the base plate 110, and FIG. 6 is a plan view showing the welding points of the lower cross beam 132 to the base plate 110.

[0059] The cross beam 130 is an important member that reinforces the lateral rigidity of the pack case 100, and is connected to the base plate 110 by welding, bolt fastening, etc. Welding is often used in consideration of fastening strength, productivity, weight reduction, etc., but in this case, a weld bead 135 formed on the welded surface of the cross beam 130 and the base plate 110 causes problems with the safety and capacity of the battery pack 200.

[0060] That is, a plurality of cell stacks 210 are mounted inside the cross beam 130, but in particular in a cell-to-pack structure without a module housing or a simplified one, the cell stacks 210 are interfered with by the weld beads 135, and the cell stacks 210 interfered with by the weld beads 135 are easily damaged or broken in an environment where vibration, impact, etc. act for a long time, which may cause serious safety problems such as fire. In addition, a design that avoids the interference of the weld beads 135 reduces the energy density of the battery pack 200 by creating dead space.

[0061] The welded structure of the lower cross beam 132 in Fig. 5 and Fig. 6 can solve the problem of the weld bead 135. Referring to the drawings, the lower cross beam 132 has at least one or more concave weld grooves 134 on the boundary with the base plate 110. The lower cross beam 132 is welded to the base plate 110 through the weld grooves 134, so that the weld bead 135 is formed in the concave space in the weld groove 134, and the weld bead 135 formed in the weld groove 134 does not protrude outside the lower cross beam 132. This can prevent interference of the cell stack 210 due to the weld bead 135 and / or occurrence of a dead space due to the avoidance design.

[0062] The size of the weld groove 134 may be designed taking into consideration the size of the welding tool tip according to the welding method and the size of the weld bead 135. For example, since the tip size is small in wire laser welding and the size of the weld bead 135 is also about 2 to 3 mm, the size of the weld groove 134 may be made to a height and depth of about several millimeters accordingly.

[0063] In one embodiment of the present invention, the welding grooves 134 may be provided on both sides of the lower cross beam 132. At this time, as shown in Fig. 6, the welding grooves 134 provided on both sides of the lower cross beam 132 may be arranged so as not to overlap at least a portion of each other in the direction in which they face each other, in other words, may be arranged alternately and distributed with each other. By distributing the welding grooves 134 evenly on both sides of the lower cross beam 132, it is possible to ensure stable welding strength while reducing the risk of deformation due to welding heat.

[0064] Third embodiment 7 and 8 show a pack case 100 according to a third embodiment of the present invention. The third embodiment of FIG. 7 and FIG. 8 is characterized in that a lower cross beam 132 and an upper cross beam 136 are each provided with a binding groove 140 for regulating the installation position of the cell stack 210. For example, when a plurality of cell stacks 210 are housed in the pack case 100 as a cell-to-pack structure without a separate module housing, the installation position of the cell stack can be firmly regulated using the binding groove 140 of the cross beam 130. The plurality of cell stacks 210, the position of which is regulated, are installed at an accurate position and the position is unlikely to fluctuate even during use of the battery pack 200, thereby improving the stability of the battery pack 200.

[0065] 7 shows one embodiment of the binding groove 140, in which the binding groove 140 is formed in the form of an open groove 142 with the joining surface between the lower cross beam 132 and the upper cross beam 136 as an opening. In other words, the binding groove 140 in FIG. 7 is formed in the form of a long groove in half of the lower cross beam 132 and the upper cross beam 136, and one side of each long groove, i.e., the joining surface between the lower cross beam 132 and the upper cross beam 136, forms an open entrance.

[0066] 8 shows another embodiment of the binding groove 140, in which the binding groove 140 is formed in the form of a hole 144 separated from each other by the boundary of the joining surface of the lower cross beam 132 and the upper cross beam 136. That is, unlike the embodiment of FIG. 7, even when the lower cross beam 132 and the upper cross beam 136 are joined, the pair of binding grooves 140 are not connected into one. The shape of the hole 144 is shown as a semicircular hole in FIG. 8, but is not limited thereto, and various other shapes not shown in the drawing, such as a circular hole or a square hole, can be applied.

[0067] 8 may include a guide groove 145 that connects the coupling surface between the lower cross beam 132 and the upper cross beam 136 to the hole 144. The guide groove 145 is for facilitating sliding of the protrusion structure 214 that is fastened to the binding groove 140, which will be described in more detail below.

[0068] 9 and 10 are diagrams for explaining a configuration in which the installation positions of a plurality of cell stacks 210 are restricted by the binding grooves 140 in FIG. 7. FIG. 9 shows a configuration in which a plurality of cell stacks 210 are mounted on a pack case 100 of the third embodiment. The illustrated cell stack 210 includes a bus bar frame assembly 212 that is coupled to the cell stack 210 at both ends (both ends in the lateral direction based on the drawing) from which the leads protrude, and the bus bar frame assembly 212 has a protrusion structure 214 that is fastened to each of the binding grooves 140 of the lower cross beam 132 and the upper cross beam 136. The protrusion structure 214 provided on the bus bar frame assembly 212 as the protrusion structure 214 corresponding to the binding grooves 140 in FIG. 7 forms a fin structure 215 corresponding to a form in which the open grooves 142 of the lower cross beam 132 and the upper cross beam 136 are connected together.

[0069] Fig. 10 shows a structure in which a bus bar frame assembly 212 coupled to a plurality of cell stacks 210 is coupled to the binding groove 140 in Fig. 7. In order to clearly understand the third embodiment, the plurality of cell stacks 210 are not shown in Fig. 10, and the positions of adjacent cell stacks 210 on both sides sharing one cross beam 130 are regulated by the same binding groove 140.

[0070] To mount the cell stacks 210, only the lower cross beam 132 of the cross beam 130 is installed in the pack case 100, and the opening of the open groove 142, which is the binding groove 140 of the lower cross beam 132, is open upward. As a result, when the multiple cell stacks 210 are inserted between the lower cross beams 132 from top to bottom, about half of the fin structure 215 of the bus bar frame assembly 212 is fitted into the open groove 142, and such fastening between the fin structure 215 and the open groove 142 occurs at both ends of the multiple cell stacks 210, so that the installation positions of the multiple cell stacks 210 are aligned.

[0071] Furthermore, by coupling the upper cross beam 136 to the lower cross beam 132, the remaining portion of the fin structure 215 is fitted into the open groove 142 of the upper cross beam 136, thereby completing a form in which the entire fin structure 215 of the bus bar frame assembly 212 is constrained within the open groove 142 that is connected to one another by the coupling of the lower cross beam 132 and the upper cross beam 136. Therefore, the positions of the multiple cell stacks 210 are firmly regulated by the coupling of the lower cross beam 132 and the upper cross beam 136. In particular, even in the case where there is no partition member vertically crossing the storage space as in the pack case 100 of FIG. 9 shown by way of example, and therefore no means for restricting the positional relationship between the cell stacks 210 facing each other in the vertical direction, the pack case 100 of the third embodiment can accurately regulate the mounting positions of all the cell stacks 210 by the binding groove 140 of the cross beam 130 and the protrusion structure 214 of the cell stack 210.

[0072] 11 shows a structure in which the busbar frame assembly 212 is coupled to the binding groove 140 of FIG. 8. Basically, the embodiment of FIG. 8 is the same in that the position of the multiple cell stacks 210 is regulated by the coupling of the lower cross beam 132 and the upper cross beam 136, but there is a difference in the manner in which the protrusion structure 214 is fastened to the binding groove 140. As shown in FIG. 8, the binding groove 140 is formed in the form of a hole 144 separated from each other by the coupling surface of the lower cross beam 132 and the upper cross beam 136, and correspondingly, the protrusion structure 214 of the busbar frame assembly 212 is configured with a snap fit joint 216 including a cantilever lug 217 that is fastened to the hole 144 of the lower cross beam 132 and the upper cross beam 136.

[0073] Although the fastening groove 140 is configured in the form of an independent hole 144 without a cutout, the cantilever lug 217 of the protruding structure 214 configured in the snap-fit ​​joint 216 can be elastically bent so that the protruding portion at the end of the cantilever can enter the hole 144 and be fastened. In order to allow the cantilever lug 217 to accurately enter the hole 144 without damage, the fastening groove 140 may include guide grooves 145 connected from the joining surfaces of the lower cross beam 132 and the upper cross beam 136 to the hole 144, respectively, so that the cantilever lug 217 of the snap-fit ​​joint 216 can slide on the surface of the guide groove 145 and be smoothly fastened to the hole 144.

[0074] Meanwhile, in terms of an installation arrangement in which a plurality of cell stacks 210 are mounted between parallel cross beams 130, it is preferable that the protruding structures 214 of the plurality of cell stacks 210 are disposed on both sides of the busbar frame assembly 212 facing the respective binding grooves 140 of the lower cross beam 132 and the upper cross beam 136. The busbar frame assembly 212 may include an insulating cover 218 coupled to its front surface. The insulating cover 218 is a cover member for electrically and physically protecting the front surface of the busbar frame assembly 212 facing the side plate 120 or other cell stacks 210. The insulating cover 218 may also be configured to be easily attached and detached to the busbar frame assembly 212 by a snap-fit ​​structure, and the insulating cover 218 is designed not to block or hide the protruding structures 214 disposed on the side surfaces of the busbar frame assembly 212 (see FIG. 9).

[0075] (Fourth embodiment) 12 is a perspective view of a battery pack 200 according to an embodiment of the present invention. The battery pack 200 is completed by mounting a plurality of cell stacks 210 in each of a plurality of accommodation spaces divided by a cross beam 130 in the pack case 100 of the present invention described in the first to third embodiments. For reference, the illustrated embodiment is a battery pack 200 having a cell-to-pack structure in which a plurality of cell stacks 210 are assembled between a bus bar frame assembly 212 for electrical connection without a separate module housing, and a lead closing the upper surface is omitted to show the internal structure.

[0076] 13 is a cross-sectional view taken along line "BB" in FIG. 12, in which an insulating sheet or compression pad 220 is interposed between the contact surfaces of the lower cross beam 132 and the upper cross beam 136 and the cell stack 210. For convenience, the insulating sheet refers to a thin member, and the compression pad refers to a thick member that has a relatively elastic feel. Both are protective members for reinforcing electrical insulation and impact resistance and abrasion resistance of the cell stack 210, and play a role in protecting the cell stack 210 from the cross beam 130.

[0077] 14 to 17 show a series of processes for manufacturing a battery pack 200 using the pack case 100 of the present invention described above through the first to third embodiments. The manufacturing method for the battery pack 200 starts with a first step of preparing the pack case 100 of the present invention, in other words, the pack case 100 including a base plate 110, side plates 120 coupled along the edge of the base plate 110 to form an accommodation space therein, and a lower cross beam 132 coupled to the base plate 110 to partition the accommodation space inside the base plate 110.

[0078] In particular, in the first step, only the lower cross beam 132 of the entire cross beam 130 is prepared in the pack case 100, and in this state, the cell stack 210 is loaded. That is, the second step is a step of seating a plurality of cell stacks 210 in the storage space partitioned by the lower cross beam 132, and in particular, for productivity, a loading jig 300 that can handle a large number of cell stacks 210 at once may be used.

[0079] Fig. 14 is a perspective view showing an embodiment in which grippers 310 of a loading jig 300 gripping a plurality of cell stacks 210 enter the lower cross beam 132, and Fig. 15 is a cross-sectional view showing a state in which the loading jig 300 of Fig. 14 has entered the lower cross beam 132. For smooth operation of the loading jig 300, it is preferable that the pack case 100 prepared in the first step has a first uneven structure 133 in which recesses 133-1 and protrusions 133-2 are repeated on the lower cross beam 132 in the joining direction of the upper cross beam 136.

[0080] 14 and 15, the loading jig 300 includes grippers 310 that grip a plurality of cell stacks 210 as a unit. The loading jig 300 includes a pair of grippers 310 that grip both sides of the cell stack 210 that are parallel to the lower cross beam 132, and may include additional grippers 310 that grip other sides of the cell stack 210.

[0081] In particular, the gripper 310 gripping both sides of the cell stack 210 facing the lower cross beam 132 may include a number of legs corresponding to the positions (or the positions and number) of the recesses 133-1 of the first uneven structure 133 formed on the lower cross beam 132. As a result, the gripper 310 of the loading jig 300 enters the recesses 133-1 of the first uneven structure 133 to seat the gripped cell stacks 210 on the base plate 110.

[0082] Generally, the depth of the recess 133-1 of the first uneven structure 133 is recessed deep enough to be equal to or greater than half the total height of the cell stack 210. Therefore, the gripper 310 of the loading jig 300 can secure a gripping area equal to at least half the total height of the cell stack 210. That is, since the lower cross beam 132 has the first uneven structure 133, the gripper 310 of the loading jig 300 can firmly grip and advance the cell stack 210 without interfering with the lower cross beam 132, and the cell stack 210 can be stably placed on the base plate 110 without being subjected to impact.

[0083] Here, the cross beam 130 of the pack case 100 has the binding groove 140 described in the third embodiment, and the multiple cell stacks 210 have protrusion structures 214 that are fastened to the binding groove 140, so that the installation positions of the multiple cell stacks 210 mounted on the pack case 100 by the loading jig can be accurately controlled.

[0084] For reference, undescribed reference numeral 230 denotes a thermal resin, which plays a role in improving the heat dissipation performance of the battery pack 200 by promoting conductive heat transfer between the base plate 110 and the cell stack 210. In particular, when the bottom surface of the cell stack 210 is open in the battery pack 200 having a cell-to-pack structure, the thermal resin 230 directly mediates conductive heat transfer between the base plate 110 and the cell stack 210 without an intermediate structure such as a module housing, thereby enabling smoother heat dissipation. The thermal resin 230 is evenly applied to a suitable thickness on the base plate 110 before the cell stack 210 is mounted in the pack case 100.

[0085] 16 is a cross-sectional view showing a process of removing the loading jig 300 after seating a plurality of cell stacks 210. Since the thickness of the gripper 310 is thinner than the thickness of the lower cross beam 132, when the gripper 310 of the loading jig 300 seats a plurality of cell stacks 210 as a whole on the base plate 110 while gripping the same, the gripper 310 retreats to release the gripped state, and then can be removed directly above the lower cross beam 132.

[0086] After the plurality of cell stacks 210 are mounted as one unit in one receiving space through the above series of steps, a third step is performed in which the upper cross beam 136 is coupled to the lower cross beam 132 on which the plurality of cell stacks 210 are seated, as shown in Fig. 17. By coupling the upper cross beam 136 to the lower cross beam 132, a sufficient surface pressure can be formed for the entire height of the cell stack 210. The surface pressure applied to the cell stack 210 can effectively suppress the swelling phenomenon that occurs when the cell stack 210 is repeatedly charged and discharged. In addition, the above-mentioned insulating sheet or compression pad 220 can be attached to the grip surface of the plurality of cell stacks 210 held by the loading jig 300, and such insulating sheet or compression pad 220 also helps suppress the swelling phenomenon.

[0087] Then, the above-mentioned second and third steps, i.e., the second step of seating the multiple cell stacks 210 in the storage space partitioned by the lower cross beam 132 and the third step of connecting the upper cross beam 136 to the lower cross beam 132 on which the multiple cell stacks 210 are seated, are repeated to perform a fourth step of mounting the multiple cell stacks 210 in all of the storage spaces, thereby completing the battery pack 200 in which the cell stacks 210 are mounted without exception in the pack case 100 of the present invention.

[0088] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments, etc. in this specification are merely one embodiment of the present invention and do not fully represent the technical ideas of the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0089] 100: Pack case 110: Base plate 120: Side plate 130: Cross beam 132: Lower cross beam 133: First uneven structure 133-1: Recess 133-2:Protrusion 134: Welding groove 135: Weld bead 136: Upper cross beam 137:Second uneven structure 137-1: Recess 137-2:Protrusion 138: Bolt 140: Binding groove 142: Open groove 144: Hole 145: Guide groove 200: Battery pack 210: Cell stack 212: Busbar frame assembly 214:Protrusion structure 215: Fin structure 216: Snap fit joint 217: Cantilever lug 218: Insulating cover 220: Insulation sheet (compression pad) 230: Thermal resin 300: Loading jig 310: Gripper

Claims

1. A base plate; a side plate coupled along an edge of the base plate, the side plate forming an accommodation space therein; a lower cross beam coupled to the base plate so as to laterally divide an inner storage space of the base plate; an upper cross beam coupled to the lower cross beam; The pack case has a lower cross beam and an upper cross beam each provided with a binding groove for regulating the installation position of the cell stack.

2. The pack case according to claim 1 , wherein the upper cross beam is joined upwardly to the lower cross beam to form a single cross beam.

3. the lower cross beam has a first uneven structure in which recesses and protrusions are alternately formed in a coupling direction of the upper cross beam, The pack case according to claim 1 , wherein the upper cross beam has a second uneven structure that is complementary to the first uneven structure.

4. the lower cross beam is welded to the base plate; The pack case of claim 3 , wherein the upper cross beam is bolted to the lower cross beam.

5. The lower cross beam and the upper cross beam are made of different materials, The pack case according to claim 4 , wherein the upper cross beam is made of a material that is lighter than the lower cross beam.

6. The lower cross beam is The pack case according to claim 1 , further comprising at least one recessed weld groove on an interface with the base plate.

7. The weld groove is The pack case according to claim 6 , provided on both sides of the lower cross beam.

8. The weld grooves provided on both sides of the lower cross beam each include The pack case according to claim 7 , wherein the first and second electrodes are disposed in a dispersed manner so as not to overlap at least partially along a direction in which they face each other.

9. the lower cross beam is welded to the base plate through the weld groove; The pack case according to claim 8 , wherein a weld bead formed within the weld groove does not protrude outside the lower cross beam.

10. The binding groove is The pack case according to claim 1 , wherein a joining surface between the lower cross beam and the upper cross beam is formed in the form of an open groove having an opening.

11. The binding groove is The pack case according to claim 1 , wherein the lower cross beam and the upper cross beam are formed in the form of holes separated from each other with a joining surface between the lower cross beam and the upper cross beam as a boundary.

12. The binding groove is The pack case according to claim 11 , further comprising a guide groove extending from a joining surface between the lower cross beam and the upper cross beam to the hole.

13. A pack case according to any one of claims 1 to 9, a plurality of cell stacks mounted in the divided storage spaces of the pack case.

14. The plurality of cell stacks are a bus bar frame assembly coupled to the cell stack at both ends from which the leads protrude, The battery pack of claim 13 , wherein the bus bar frame assembly comprises a protrusion structure fastened to each fastening groove of the lower cross beam and the upper cross beam.

15. The binding groove is formed in the form of an open groove having an opening at a joining surface between the lower cross beam and the upper cross beam, The battery pack of claim 14 , wherein the protrusion structure is a fin structure that corresponds to a shape in which the open grooves of the lower cross beam and the upper cross beam are connected together.

16. The binding grooves are formed in the form of holes separated from each other by a boundary of a joining surface between the lower cross beam and the upper cross beam, 15. The battery pack of claim 14, wherein the protruding structure is a snap-fit ​​joint including a cantilever lug that fastens into holes in the lower and upper cross beams.

17. The binding groove includes a guide groove connected from a coupling surface between the lower cross beam and the upper cross beam to the hole, The battery pack according to claim 16 , wherein the protrusion structure is fastened to the hole by the cantilever lug sliding on a surface of the guide groove.

18. The protrusion structure is The battery pack according to claim 14 , wherein the bus bar frame assembly is disposed on both sides of the bus bar frame assembly facing the respective binding grooves of the lower cross beam and the upper cross beam.

19. The bus bar frame assembly includes:

20. The battery pack of claim 18 including an insulating cover coupled to a front surface thereof.

20. The battery pack according to claim 13 , wherein a thermal resin is interposed between the contact surfaces of the plurality of cell stacks and the base plate.

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