Battery pack

Abstract

In one example, the battery pack includes a cell array including a plurality of rectangular cells aligned in a row, a pair of side plates respectively arranged on both side surfaces of the cell array, and a pair of end plates respectively arranged on front and rear surfaces of the cell array, with both widthwise ends of the end plates fixed to side brackets provided at both longitudinal ends of the side plates, forming a battery block in which the cell array is constrained into one block, and a pack case in which a plurality of the battery blocks are mounted, and the end plates include end brackets fixed to mounting portions provided on the pack case.

Description

[Technical field]

[0001] The present invention relates to a battery pack in which a battery block can be easily attached and detached by improving an attachment structure of the battery block to the battery pack, no adhesive is used, damage when the battery block is removed is prevented, and smooth cooling of the lower part of the battery block can be achieved.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0163109 dated November 29, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be recharged, and they have been much researched and developed in recent years due to their potential for miniaturization and large capacity. The demand for secondary batteries as an energy source is rapidly increasing due to the increasing technological development and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in response to the modern demand for environmental protection.

[0004] Secondary batteries are classified into coin type batteries, cylindrical type batteries, square type batteries, and pouch type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case of the secondary battery is a power generating element capable of charging and discharging, which is made of a laminated structure of electrodes and a separator.

[0005] The secondary battery may be in the form of a battery pack, which is a group of multiple battery cells. The battery pack may be installed in devices that require high energy, such as electric vehicles, by increasing the energy density. The battery pack electrically connects multiple battery cells to output a specified amount of power, cools the battery cells that may become hot during operation, and includes various safety devices to respond to emergency situations such as fire.

[0006] One of the important issues for battery packs is to increase the energy density per unit volume. This means that the key is how efficiently the space inside the battery pack can be utilized. In other words, it is necessary to be able to mount more battery cells in the same pack space, and one effective solution is to simplify the structure of the battery pack as much as possible.

[0007] In addition, as more battery cells are installed in the same pack space, a structure is required in which the heat generated in the battery cells during the charging and discharging process can be efficiently transferred to the pack case, and a multifaceted design plan is also required that takes into account not only the secure installation of the battery cells but also the maintenance of the battery pack. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a battery pack which can simplify the structure of the battery pack, improve space utilization rate, and reduce costs, and which firmly mounts battery cells mounted in the battery pack while allowing easy removal of the battery cells when required for maintenance.

[0009] 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]

[0010] The present invention relates to a battery pack, and in one example, the battery pack includes: a cell array including a plurality of rectangular cells aligned in a row; a pair of side plates respectively arranged on both side surfaces of the cell array; and a pair of end plates respectively arranged on front and rear surfaces of the cell array, with both widthwise ends of the end plates fixed to side brackets provided at both longitudinal ends of the side plates, thereby constraining the cell array to one block; and a pack case in which a plurality of the battery blocks are mounted, and the end plates include end brackets fixed to mounting portions provided on the pack case.

[0011] The side bracket may also include an end bracket that is fixed to a mounting portion provided on the pack case.

[0012] In one embodiment of the present invention, the end bracket has a fastening surface parallel to the width direction, and one or more fastening holes are formed in the fastening surface, and the end bracket is fixed to the mounting part through the fastening holes.

[0013] And, the end bracket may include a reinforcing rib perpendicular to the fastening surface.

[0014] Meanwhile, in one embodiment of the present invention, the side plate may be a single plate bent in a "U" shape with an open upper end to form a space therein.

[0015] The side plate may have concave surfaces on both sides of the bent plate, and at least one joining rib may be provided along the longitudinal direction, where the facing concave surfaces are joined to each other.

[0016] An upper flange is bent at the upper end of the side plate to come into contact with the upper surface of the cell array.

[0017] With the end brackets secured to the mounting portions, the upper flanges apply a downward securing force that presses the cell array against the base plate of the pack case.

[0018] In one example, the edge of the upper flange that contacts the upper surface of the cell array may be spaced apart from the electrode terminals of the prismatic cells by a distance in the range of 5 to 10 mm.

[0019] The pack case includes a base plate forming a bottom surface, side frames forming walls along all four sides of the base plate, and an upper cover sealing the top surface of the pack case, and a cooling flow path through which a cooling medium flows may be provided inside the base plate.

[0020] A thermally conductive thermal interface material (TIM) may be interposed between contact surfaces of the base plate and the battery block.

[0021] The side bracket may include a fastening groove into which a welding bolt protruding from the end plate is inserted, and the welding bolt and the fastening groove may be joined to each other by welding.

[0022] Further, the side bracket may have the fastening grooves on both left and right sides with respect to a center in a width direction of the side plate.

[0023] As a result, another cell array arranged along the width direction shares the side plate, and the welding bolts provided on a pair of end plates arranged on the front and rear surfaces of the another cell array are fixed to the fastening grooves of the side bracket, thereby allowing the multiple cell arrays to be expanded along the width direction. Effect of the Invention

[0024] The battery pack of the present invention having the above-mentioned configuration has a simple structure in which the end plates, which are connected via side brackets provided on the side plates, bind the front, rear and side surfaces of the cell array consisting of a plurality of rectangular cells into one block, thereby improving the space utilization rate of the battery pack and reducing the cost by simplifying the structure of the battery block.

[0025] In addition, the battery pack of the present invention is directly fixed to the pack case using end brackets provided on the end plates that bind the cell array into one block, so that the battery block can be firmly attached without using adhesives, and can also be easily removed for maintenance without damage.

[0026] 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.

[0027] 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]

[0028] [Figure 1] 1 is a view showing a battery block according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the battery block of FIG. 1. [Diagram 3] 1 is a diagram showing a side plate. [Figure 4] FIG. 4 is a cross-sectional view taken along line "AA" in FIG. [Diagram 5] 4 is an enlarged view showing a connection structure between a side plate and an end plate; [Figure 6]1 is a view showing a structure in which a battery block is expanded in a width direction; [Figure 7] 1 is a view showing a structure in which a battery block is expanded in a width direction; [Figure 8] 4 is a diagram illustrating an example of a structure in which a battery block is fixed to a pack case according to the present invention; [Figure 9] 4 is a diagram illustrating an example of a structure in which a battery block is fixed to a pack case according to the present invention; [Figure 10] 13 is a diagram showing a structure in which an upper flange of a side plate fixes a cell array. [Figure 11] 1 is a diagram showing a heat transfer structure between a battery block and a base plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The present invention relates to a battery pack, and in one example, the battery pack includes a cell array including a plurality of rectangular cells aligned in a row, a pair of side plates respectively disposed on both sides of the cell array, and a pair of end plates respectively disposed on front and rear sides of the cell array, both widthwise ends of the end plates being fixed to side brackets provided at both longitudinal ends of the side plates, a battery block in which the cell array is constrained into one block, and a pack case in which a plurality of the battery blocks are mounted.

[0034] The end plate includes an end bracket that is fixed to a mounting portion provided on the pack case.

[0035] The battery pack of the present invention having such a configuration has a simple structure in which the end plates, which are connected via side brackets provided on the side plates, bind the front, rear and side surfaces of the cell array consisting of a plurality of rectangular cells into one block, thereby improving the space utilization rate of the battery pack and reducing the cost by simplifying the structure of the battery block.

[0036] In addition, the battery pack of the present invention is directly fixed to the pack case using end brackets provided on the end plates that bind the cell array into one block, so that the battery block can be firmly attached without using adhesives, and can also be easily removed for maintenance without damage.

[0037] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, directions such as front-back, up-down, left-right, and right-left directions used in the following description are intended to facilitate understanding of the invention, and unless otherwise specified, are based on directions shown in the drawings.

[0038] (First embodiment) Fig. 1 is a view showing a battery block 10 according to one embodiment of the present invention, and Fig. 2 is an exploded perspective view of the battery block 10 of Fig. 1. The configuration of the battery block 10 mounted in the battery pack 600 of the present invention will be described below first. The description of the configuration of the battery block 10 is useful for understanding the mounting structure of the pack case 602.

[0039] Referring to the accompanying Figures 1 and 2, a battery block 10 according to the present invention includes a pair of side plates 200, a pair of end plates 300 coupled to the side plates 200 to form a parallelepiped-shaped space, and a cell array 100 accommodated in the parallelepiped space.

[0040] The cell array 100 refers to a cell group consisting of a number of prismatic cells 110 aligned in a row. Each prismatic cell 110 is a completed prismatic secondary battery that can be charged and discharged independently, and in the illustrated embodiment, a cell array 100 is shown as an example in which 12 prismatic cells 110 are assembled together. All the prismatic cells 110 are generally configured to have the same specifications, and the prismatic cells 110 aligned in a row generally form a parallelepiped shape.

[0041] For reference, the illustrated prismatic cell 110 corresponds to a one-way prismatic cell 110 in which positive and negative electrode terminals 112 are all disposed on the upper surface, and a venting device 114 is provided between the pair of electrode terminals 112. The venting device 114 is a device corresponding to a safety valve that bursts when pressure acts inside the prismatic cell 110 to relieve the internal pressure, and may include, for example, a rupture disk made of a thin metal plate member with a notch. When the internal pressure of the sealed prismatic cell 110 increases, the rupture disk generates tensile deformation over the entire thin plate due to the pressure, and the weak notch portion breaks to relieve the internal pressure of the prismatic cell 110.

[0042] The electrode terminals 112 of the prismatic cells 110 on the cell array 100 may be arranged in a row with the same polarity or with opposite polarity alternating for convenience of parallel or serial electrical connection. In other words, the arrangement of a plurality of prismatic cells 110 in a row does not necessarily mean that the polarities of the electrode terminals 112 are aligned in a row.

[0043] A pair of side plates 200 are disposed on both sides of the cell array 100, and a pair of end plates 300 are disposed on the front and rear sides of the cell array 100. Both ends of the end plate 300 in the width direction W are fixed to side brackets 210 provided on both ends of the side plate 200 in the longitudinal direction L, and the cell array 100 is bound into one block by the mutual connection of the end plate 300 and the side plate 200.

[0044] Fig. 3 is a view showing a side plate 200, and Fig. 4 is a cross-sectional view taken along line "AA" in Fig. 3. The side plate 200 shown in the drawing is made of a single plate bent into a "∪" shape with an open top to form a space inside. By bending the single plate into a "∪" shape with an open top, the side plate 200 is lightweight yet exhibits excellent mechanical strength.

[0045] 3 and 4, the side plate 200 has concave surfaces 222 on both sides of the bent plate, and the facing concave surfaces 222 are joined to each other to form a joining rib 220. At least one such joining rib 220 is provided along the longitudinal direction L of the side plate 200, and in the illustrated embodiment, a total of three joining ribs 220 are formed at both ends and the center of the side plate 200.

[0046] A single plate bent into a "∪" shape has excellent durability and strength against compression and tension in the longitudinal direction L due to the bent structure, but can be relatively vulnerable to forces in the height direction H. The joining rib 220 improves rigidity against forces in the height direction H by bundling the concave surfaces 222 on both sides of the side plate 200 into one by joining them by welding or bundling them by rivets or the like.

[0047] Such a structure of the side plate 200, i.e., a single plate structure bent into a "u" shape and a structure of the interconnected concave surfaces 222, allows the side plate 200 to have a strong mechanical rigidity while being lightweight. As a result, in the battery block 10 of the present invention, the side plate 200 replaces the cross beam structure provided in the conventional battery pack, and the structure of the battery pack 600 is accordingly simplified, improving the space utilization rate of the battery pack 600, further increasing the energy density per the same volume, and reducing the cost.

[0048] An upper flange 230 is bent at the upper end of the side plate 200 to contact the upper surface of the cell array 100. The upper flange 230 generates a downward fixing force that presses the cell array 100 to the bottom when the battery block 10 is mounted in the pack case 602. The structure in which the battery block 10 of the present invention is mounted in the pack case 602 will be described in more detail with reference to Figs. 8 and 9 below.

[0049] 5 is an enlarged view showing a connection structure between the side plate 200 and the end plate 300. The side bracket 210 provided on the side plate 200 has a fastening groove 212 into which a welding bolt 310 protruding from the end plate 300 is inserted, and the welding bolt 310 and the fastening groove 212 are joined to each other by welding.

[0050] Welding bolts 310 provided on a pair of end plates 300 arranged on the front and rear surfaces of the cell array 100 provide fastening points for the side brackets 210, and the assembly positions of the side plates 200 and the end plates 300 are provisionally aligned by fitting the fastening grooves 212 into the welding bolts 310. For stable and firm connection between the side plates 200 and the end plates 300 and for strong restraint on the cell array 100, the welding bolts 310 and the fastening grooves 212 may be provided in pairs, one above and one below, based on the center of the height direction H of the cell array 100.

[0051] 1 to 3 and 5, end plate 300 includes an end bracket 400 fixed to pack case 602. Side bracket 210 also includes an end bracket 400 fixed to pack case 602.

[0052] The end brackets 400 provided on the end plates 300 and the side plates 200 have fastening surfaces 410 parallel to the width direction W, and one or more fastening holes 412 are formed on the fastening surfaces 410 of the end brackets 400. The fastening surfaces 410 of the end brackets 400 are seated on mounting parts 640 provided on the pack case 602 (see FIG. 9 ), and the battery block 10 is fixed to the pack case 602 by joining or fastening the end brackets 400 to the mounting parts 640 of the pack case 602 via the fastening holes 412.

[0053] The end bracket 400 may have a reinforcing rib 420 in the form of a right-angled triangle perpendicular to the fastening surface 410 to reinforce the rigidity against a load in the height direction H. For reference, one or more concave surfaces 320 similar to the concave surface 222 of the side plate 200 may be bent to reinforce the rigidity of the end plate 300 itself, and an upper flange 330 may be provided on the upper end of the end plate 300 to stably fix the cell array 100.

[0054] Second embodiment 6 and 7 are diagrams showing a structure in which the battery block 10 of FIG.

[0055] The battery block 10 of the present invention can expand the number of cell arrays 100 to a desired number along the width direction W via the side plates 200 and the side brackets 210. In the second embodiment of the present invention, one embodiment of such expansion of the battery block 10 will be described.

[0056] 6, the side bracket 210 has fastening grooves 212 on both the left and right sides of the center of the side plate 200 in the width direction W. This makes it possible to connect one end plate 300 to each side of the side plate 200 in the width direction W.

[0057] As shown in FIG. 7, another cell array 100 arranged along the width direction W shares one central side plate 200, and the welding bolts 310 provided on a pair of end plates 300 arranged on the front and rear surfaces of the other cell array 100 are fixed to the fastening grooves 212 of the side brackets 210, thereby allowing the multiple cell arrays 100 to be expanded along the width direction W.

[0058] As described above, the side bracket 210 has fastening grooves 212 on both the left and right sides, so that one end plate 300 can be coupled to each side of one side plate 200, and adjacent cell arrays 100 share one side plate 200, so that in a structure in which a plurality of battery blocks 10 are connected, the total number of side plates 200 required is one more than the number of cell arrays 100. Therefore, the space efficiency of the battery pack 600 equipped with the battery block 10 of the present invention is further improved.

[0059] Third embodiment In the third embodiment of the present invention, a structure will be described in which the above-mentioned battery block 10 expanded in the width direction W is mounted in a pack case 602. FIGS. 8 and 9 are drawings showing a structure in which the battery block 10 is fixed to the pack case 602.

[0060] A pack case 602 in which a plurality of battery blocks 10 are mounted includes a base plate 610 forming a bottom surface, side frames 620 forming walls along the four sides of the base plate 610, and an upper cover 630 sealing the upper surface of the pack case 602. The illustrated pack case 602 shows an example in which two battery modules 500, each having a side plate 200 and an end plate 300 coupled in a lattice shape such that three cell arrays 100 are arranged in a row, are arranged in two rows (in this specification, an assembly in which a plurality of battery blocks are connected together via a side plate according to the second embodiment is referred to as a battery module). For reference, one battery module 500 is omitted in FIG. 8 so that the structure of the pack case 602 can be clearly shown.

[0061] In one battery module 500 having three cell arrays 100 arranged in a row, end brackets 400 are exposed along the front and rear end plates 300, and one end bracket 400 is also exposed on the side bracket 210 between the end plates 300.

[0062] 9, a pack case 602 is provided with rail-shaped mounting parts 640 corresponding to fastening surfaces 410 of end brackets 400 protruding from the front and rear surfaces of a battery module 500. The mounting part 640 includes a pair of side mounting parts 642 coupled to or integrally formed with the side frames 620, and a center mounting part 644 provided across the center of the base plate 610, which are arranged in parallel.

[0063] When the battery module 500 is inserted into the space between the side mounting portion 642 and the center mounting portion 644, the fastening surface 410 of the end bracket 400 faces the mounting portion 640 of the pack case 602, and all of the battery blocks 10 are fixed together to the pack case 602 by joining or fastening the end bracket 400 to the mounting portion 640 of the pack case 602 through the fastening holes 412.

[0064] Here, when the end brackets 400 of each battery block 10 are coupled and fixed to the mounting portions 640 of the pack case 602, a downward fixing force pressing the cell array 100 against the base plate 610 is naturally generated in the side plates 200 and, further, in the upper flanges 330, 230 bent and formed at the upper ends of the end plates 300, thereby firmly adhering the cell array 100 to the base plate 610.

[0065] The close contact between the cell array 100 and the base plate 610 plays an important role in smoothly transferring heat generated in the cell array 100 to the base plate 610. Therefore, it can be said that it is advantageous for the upper flanges 230, 330 to generate a sufficient downward fixing force to control the tolerance in a direction in which a minute gap occurs between the fastening surface 410 of the end bracket 400 and the mounting portion 640 when the battery block 10 or the battery module 500 is inserted into the pack case 602.

[0066] 10 is a diagram showing a structure in which the upper flange 230 of the side plate 200 fixes the cell array 100. As described above, the upper flange 230 of the side plate 200 contacts the upper surface of the adjacent cell array 100 that shares the side plate 200, and generates a downward fixing force that tightly attaches the cell array 100 to the base plate 610 when the battery block 10 is mounted to the pack case 602 via the end bracket 400. However, since there are no corresponding cell arrays 100 for the upper flanges 230 at both ends in the width direction of the pack case 602, it is preferable to form flange mounting parts 650 in the side frame 620 and support the vacant upper flanges 230 in the flange mounting parts 650 to achieve stable mounting while allowing a uniform pressure force to act on the edge of the cell array 100.

[0067] 10, the edge of the upper flange 230 that contacts the upper surface of the cell array 100 is spaced a certain distance, for example, a distance d in the range of 5 to 10 mm, from the electrode terminals 112 of the prismatic cells 110. In order to ensure that the downward fixing force of the upper flange 230 acts as uniformly as possible on the cell array 100, the wider the upper flange 230, the better; however, the edge of the upper flange 230 is spaced a certain distance from the electrode terminals 112 in consideration of the convenience of electrical connection to the prismatic cells 110 and the risk of short circuiting.

[0068] 11 is a diagram showing a heat transfer structure between a battery block 10 and a base plate 610. The battery pack 600 of the present invention has excellent adhesion of the battery block 10 to the base plate 610 due to the configuration of the end bracket 400 and the upper flange 230. Therefore, the battery pack 600 of the present invention does not need to use an adhesive to fix the lower part of the battery block 10, and since no adhesive is used, the lower part of the battery block 10 is cooled smoothly, i.e., heat transfer is facilitated. In addition, since no adhesive is used, not only is the installation process of the battery block 10 simplified, but damage to the battery block 10 when it is removed is prevented.

[0069] In the illustrated embodiment, the base plate 610 includes a heat sink 612 having cooling channels 614 through which a cooling medium flows. The heat sink 612 includes a lower plate having the cooling channels 614 formed therein and an upper plate joined to the lower plate to form a fluid-tight seal, and the upper plate is provided with a pair of inlet / outlet adapters 616 that form an inlet / outlet for the cooling medium flowing through the cooling channels 614 (only one inlet / outlet adapter is shown in FIG. 11 due to the orientation of the drawing).

[0070] A thermally conductive thermal interface material 618 (TIM) may be interposed between the contact surface between the heat sink 612 of the base plate 610 and the battery block 10. The thermally conductive thermal interface material 618 refers to a known material having a significantly higher thermal conductivity than metal materials such as aluminum, and the thermally conductive thermal interface material 618 contributes to quickly transferring heat generated in the battery block 10 to the heat sink 612 by having a high thermal conductivity and acting as a filler for filling minute irregularities on the contact surface. The function of the thermally conductive thermal interface material 618 is reliably guaranteed by the close contact between the base plate 610 and the battery block 10 by the end bracket 400 and the upper flange 230.

[0071] 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]

[0072] 10: Battery block 100: Cell array 110: Square cell 112: Electrode terminal 114: Venting equipment 200: Side plate 210: Side bracket 212: Fastening groove 220: Joint rib 222: Concave 230: Upper flange 300: End plate 310: Welding bolts 320: Concave 330: Upper flange 400: End bracket 410: Fastening surface 412: Concluding hole 420: Reinforcement rib 500: Battery module 600: Battery pack 602: Pack case 610: Base plate 612: Heat sink 614: Cooling channel 616: Inflow / Outflow Adapter 618: Thermally conductive thermal interface materials 620: Side frame 630: Top cover 640: Mounting part 642: Side mounting part 644: Center mounting part 650: Flange mounting part W: Width direction L: Longitudinal H: Height

Claims

1. a battery block including a cell array including a plurality of rectangular cells aligned in a row, a pair of side plates disposed on both sides of the cell array, respectively, and a pair of end plates disposed on front and rear sides of the cell array, respectively, wherein both ends in a width direction of the end plates are fixed to side brackets provided on both ends in a length direction of the side plates, and the cell array is bound into one block; a pack case in which a plurality of the battery blocks are mounted; The end plate includes an end bracket fixed to a mounting portion provided on the pack case.

2. The side bracket is The battery pack according to claim 1 , further comprising an end bracket fixed to the mounting portion provided on the pack case.

3. The end bracket is The battery pack according to claim 1 or 2, further comprising a fastening surface parallel to a width direction, the fastening surface having one or more fastening holes formed therein, the battery pack being fixed to the mounting portion through the fastening holes.

4. The end bracket is The battery pack of claim 3 , further comprising a reinforcing rib perpendicular to the fastening surface.

5. The side plate is 10. The battery pack of claim 1, wherein the battery pack is a single plate bent into an open "U" shape at its top to form a space therein.

6. The side plate is The folded plate has concave surfaces on both sides; The battery pack according to claim 5 , wherein the concave surfaces face each other and are joined together along the longitudinal direction of the concave surfaces to form at least one joining rib.

7. The upper end of the side plate is The battery pack according to claim 5 , wherein an upper flange contacting an upper surface of the cell array is formed by bending.

8. The battery pack according to claim 7 , wherein the end bracket is fixed to the mounting portion, so that the upper flange applies a downward fixing force that presses the cell array against a base plate of the pack case.

9. The battery pack according to claim 8, wherein an edge of the upper flange in contact with the upper surface of the cell array is spaced apart from the electrode terminal of the prismatic cell by a distance in the range of 5 to 10 mm.

10. The pack case includes: the pack case includes a base plate forming a bottom surface, side frames forming walls along four sides of the base plate, and an upper cover sealing an upper surface of the pack case, The battery pack according to claim 8 , wherein an interior of the base plate is provided with a cooling passage through which a cooling medium flows.

11. The battery pack according to claim 10 , wherein a thermally conductive thermal interface material is interposed between contact surfaces of the base plate and the battery block.

12. The side bracket has a fastening groove into which a welding bolt protruding from the end plate is inserted, The battery pack according to claim 1 , wherein the weld bolt and the fastening groove are interconnected by welding.

13. The side bracket is The battery pack according to claim 12 , wherein the fastening grooves are provided on both left and right sides of a width direction center of the side plate.

14. Another cell array arranged along the width direction shares the side plate, 14. The battery pack of claim 13, wherein welding bolts provided on a pair of end plates respectively disposed on front and rear surfaces of the other cell array are fixed to fastening grooves of the side brackets, thereby expanding the plurality of cell arrays along a width direction.

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