Battery pack

Abstract

The present invention relates to a battery pack that includes a plurality of battery assemblies and a pack housing that can accommodate the battery assemblies, and that includes a unit frame assembly to which the pack housing can be joined in a row along a lateral direction, thereby allowing the bottom area of ​​the battery pack to be freely expanded. In addition, the battery pack of the present invention can be simplified in structure by directly housing the battery assembly in the pack housing without a battery module, and can reduce the number of parts and the space occupied by the parts, thereby providing a battery pack that can reduce manufacturing costs and increase the energy density of the battery pack.

Description

[Technical field]

[0001] The present invention relates to a battery pack that contains a plurality of battery assemblies.

[0002] More specifically, the present invention relates to a battery pack in which the size of the battery pack can be freely changed and expanded in accordance with the type, size, number, required electrical capacity, etc. of the battery cells by constructing the battery pack using unit frames that can be used as common parts.

[0003] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0078225 dated June 27, 2022 and Korean Patent Application No. 10-2023-0070836 dated June 1, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0004] A battery pack applied to an electric vehicle or the like has a structure in which a number of battery modules, each including a plurality of secondary batteries, are connected in series or parallel to obtain high output. The secondary battery can be repeatedly charged and discharged by electrochemical reactions between components including positive and negative electrode current collectors, separators, active materials, electrolytes, etc.

[0005] However, conventional battery packs have the following problems.

[0006] When the type or size of the battery cells is different, or when the capacity of the battery pack needs to be changed by increasing or decreasing the number of battery cells, the size and specifications of the battery pack that accommodates the battery cells must be changed. However, in conventional battery packs, the specifications of the base plate on which the battery cells are mounted are set, and the size and area of ​​the battery pack cannot be freely changed. In particular, when it is necessary to manufacture a wide variety of battery packs with new specifications and capacities according to the types of newly released automobiles, it is difficult to respond to this. In other words, conventional battery packs have a problem in that the degree of freedom in design changes is significantly reduced.

[0007] Therefore, it is desirable to develop a technology that allows the size and area to be freely changed depending on the type of battery cell or the type of automobile in which the cell is used. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-2022-0014027 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention is intended to solve the above-mentioned problems, and has an object to provide a battery pack in which the size of the battery pack can be freely changed according to required specifications by constructing the battery pack from unit frames that can be used as common parts. [Means for solving the problem]

[0010] In order to achieve the above object, a battery pack according to an embodiment of the present invention includes a plurality of battery assemblies and a pack housing that accommodates the battery assemblies. The pack housing is an assembly of a plurality of unit frames, each having a side wall portion and a base portion extending in one direction from a lower end of the side wall portion, and includes a unit frame assembly in which the unit frames are coupled to one row along a lateral direction by sequentially coupling a lower end of a side wall portion of a base portion of one unit frame to an extended end of one side of a base portion of a succeeding unit frame, a front frame coupled to a front-rear direction front end of the unit frame assembly, and a rear frame coupled to a rear-rear direction rear end of the unit frame assembly. Each battery assembly is accommodated in each unit frame such that a lower surface of the battery assembly is supported by the base portion of the respective unit frame and both side surfaces of the battery assembly are supported by opposing side wall portions of an adjacent unit frame.

[0011] The height of the sidewall may be greater than the height of the battery assembly.

[0012] In addition, a step portion having a shape that matches the shape of the front end portion of the subsequent unit frame base portion is formed at the lower end portion of the side wall portion of the base portion of the unit frame, and the front end portion of the subsequent unit frame base portion can be joined to the step portion.

[0013] The battery pack may further include a first side frame coupled to a base portion of a unit frame at a most distal end in one side direction of the unit frame assembly.

[0014] In this case, the battery assembly accommodated in the frontmost unit frame may have a lower surface supported by a base portion of the frontmost unit frame and both side surfaces supported by the first side frame and a side wall portion of the frontmost unit frame facing the first side frame, respectively.

[0015] The unit frame assembly may further include a second side frame coupled to a side wall of the unit frame at the rearmost end in one side direction of the unit frame assembly.

[0016] A width of a side wall portion of a rearmost unit frame in one side direction of the unit frame assembly may be equal to a width of the first side frame.

[0017] The unit frame at the most distal end in one side direction of the unit frame assembly may further include a second side wall portion facing the side wall portion at an extension end in one side direction of the base portion.

[0018] The battery assembly accommodated in the unit frame at the forefront in one side direction may have a lower surface supported by the base portion of the forefront unit frame and both side surfaces supported by the side wall portion and the second side wall portion, respectively.

[0019] The width of the second side wall portion may be greater than the width of the side wall portions of the other unit frames.

[0020] In addition, the distance between opposing sidewall portions of adjacent unit frames of the unit frame assembly may be smaller than the width of each battery assembly.

[0021] The battery assembly may include at least one cushioning pad between the stacked battery cells.

[0022] A heat transfer member may be provided between the battery assembly and the base.

[0023] Moreover, the base portion may include a cooling passage therein, and the front frame and the rear frame may each include a cooling passage communicating with the cooling passage of the base portion.

[0024] In a battery pack according to one embodiment of the present invention, each unit frame has two or more side wall portions spaced apart from each other in a row along the front-rear direction, and a base portion extending in one direction from a lower end of each side wall portion and extending long along the front-rear direction. The plurality of battery assemblies are arranged in two or more rows along the front-rear direction corresponding to the number of the side wall portions, and the battery assemblies in each row may be accommodated in each unit frame such that their lower surfaces are supported by one base portion of the respective unit frames, and both side surfaces are supported by respective side wall portions of adjacent unit frames that face each other and are arranged along the front-rear direction.

[0025] In this case, the battery pack may further include a center frame located in the interval between the side wall portions spaced apart in the front-rear direction to divide the battery assemblies into row units, extending laterally along the base portion of each unit frame, and coupled to the unit frame assembly.

[0026] The pack housing may further include a pack cover coupled to the unit frame assembly while covering the battery assembly. Effect of the Invention

[0027] The present invention allows the size and area of ​​a battery pack to be freely changed by increasing or decreasing the number of assembled unit frames that can be used as common parts. Therefore, the size of the battery pack can be changed according to the required specifications, which greatly improves the design freedom of the battery pack. In addition, the unit frames can be made into standard or common parts, which reduces the unit production cost. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic diagram showing the structure of a conventional battery module. [Diagram 2] FIG. 1 is a schematic diagram of a conventional battery pack. [Diagram 3] 1 is a schematic cross-sectional view of a conventional battery pack structure. [Figure 4] 1 is a partially exploded perspective view showing a battery pack according to an embodiment of the present invention; [Diagram 5] FIG. 2 is a schematic diagram of a battery assembly contained in the battery pack of the present invention. [Figure 6] FIG. 2 is an exploded perspective view of a pack housing of the battery pack of the present invention. [Figure 7] 4 is a schematic diagram showing a process of assembling a unit frame, which is a component of the battery pack of the present invention; FIG. [Figure 8] 4 is a schematic perspective view showing a state in which a battery assembly is installed in a unit frame according to the present invention; FIG. [Figure 9] FIG. 4 is a front view showing a state in which a battery assembly is installed in a unit frame according to the present invention; [Figure 10] 4 is a schematic diagram showing a process of installing a battery assembly in the battery pack of the present invention; [Figure 11] 1 is a schematic diagram comparing a conventional battery pack with a battery pack of the present invention; [Figure 12] FIG. 4 is a partially exploded perspective view showing a battery pack according to another embodiment of the present invention. [Figure 13] FIG. 13 is a perspective view showing a modified example of the unit frame. [Figure 14] FIG. 2 is a partially exploded perspective view of a battery pack according to another embodiment of the present invention. [Figure 15] FIG. 15 is a coupling diagram of the unit frame and the battery assembly of the battery pack according to the embodiment of FIG. 14. [Figure 16] FIG. 13 is a schematic diagram of a unit frame that is a component of a battery pack according to a modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The present invention will become clearer by describing in detail preferred embodiments of the present invention with reference to the attached drawings. The embodiments described herein are illustrative in order to aid in the understanding of the invention, and it should be understood that the present invention can be implemented in various forms different from the embodiments described herein. In addition, the attached drawings are not drawn to scale in order to aid in the understanding of the invention, and the dimensions of some components may be exaggerated.

[0030] The present invention will be described in detail below.

[0031] (First embodiment) FIG. 1 is a schematic diagram showing the structure of a conventional battery module, FIG. 2 is a schematic diagram of a conventional battery pack, and FIG. 3 is a schematic cross-sectional view of the conventional battery pack structure.

[0032] 1, a conventional battery module 10 includes a module housing 12 (12A, 12B) that houses a plurality of battery cells 11, and a front end plate 13 and a rear end plate 14 that cover the front and rear ends of the module housing. In addition, a heat transfer member 1 made of a thermally conductive adhesive or the like is located between the battery cells and the module housing (see FIG. 3).

[0033] 2 and 3 show that a plurality of such battery modules 10 are installed in a pack housing 21 of a battery pack 20. Each battery module 10 is installed between partitions 22 provided on a base plate 23 of the pack housing 21. In addition, a heat transfer member 1' made of a thermally conductive adhesive or the like may be additionally disposed between the battery module and the base plate 23 on which the module is mounted, and a cooling plate 24 may be disposed under the base plate 23.

[0034] In such conventional battery packs, the standard of the base plate 23 is set, and the size and area of ​​the battery pack cannot be freely changed.

[0035] FIG. 4 is a partially exploded perspective view showing a battery pack of one embodiment of the present invention, FIG. 5 is a schematic diagram of a battery assembly accommodated in the battery pack of the present invention, FIG. 6 is an exploded perspective view of a pack housing of the battery pack of the present invention, FIG. 7 is a schematic diagram showing the joining process of a unit frame, which is a component of the battery pack of the present invention, and FIGS. 8 and 9 are schematic perspective and front views showing how a battery assembly is installed in the unit frame of the present invention.

[0036] In this specification, terms expressing directions such as front, back, left, right, up, and down may vary depending on the position of the observer and the arrangement of the object. However, in this specification, for convenience of explanation, directions such as front, back, left, right, up, and down are shown separately based on the view from the direction of the arrow (F) in Fig. 4. In other words, the front-back direction is defined as the X direction, the left-right direction is defined as the Y direction, and the height direction is defined as the Z direction.

[0037] A battery pack according to an embodiment of the present invention may include a plurality of battery assemblies and a pack housing that houses the battery assemblies.

[0038] The battery assembly may include a plurality of battery cells. The battery cells may be classified into pouch-type battery cells and can-type battery cells depending on the shape of the case. The can-type battery cells may include cylindrical battery cells and prismatic battery cells. Each of the battery cells includes an electrode assembly housed in a battery case. The electrode assembly includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assemblies may be classified into a jelly roll type and a stack type depending on the assembly shape. A jelly roll type electrode assembly is formed by winding up a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly is formed by sequentially stacking a positive electrode, a separator, and a negative electrode.

[0039] The battery assembly may be a battery module 10 having a module housing that accommodates a plurality of battery cells, as shown in Fig. 1. The battery module may have a form in which a part of the module housing that accommodates the battery cells is removed. For example, in order to simplify the structure, a battery module having a module housing in which the upper housing 12A is removed or the bottom of the lower housing 12B is removed may also be the battery assembly of the present invention.

[0040] Alternatively, as shown in FIGS. 4 and 5, a battery cell stack in a form in which the module housing itself enclosing the upper, lower, left and right sides of a plurality of battery cells is removed may also be a battery assembly.

[0041] In the embodiment disclosed in FIG. 4 and FIG. 5, a battery cell stack in which a number of battery cells 110 are stacked, that is, a cell stack unit 100, is applied as the battery assembly.

[0042] The battery cells 110 are stacked such that their sides are in contact with each other, and the sides of adjacent battery cells 110 may be fixed to each other with double-sided tape. Alternatively, a number of stacked battery cells 110 may be bound with a band 111 to form one cell stack unit 100 (see FIG. 5(a)). In this embodiment, the cell stack unit 100 may be configured to be stacked in the left-right direction (or horizontal direction) as shown in FIG. 4. However, it is also possible to configure the battery cells 110 to be stacked in the up-down direction (height direction) as necessary.

[0043] In the present embodiment, a bus bar assembly 120 may be coupled to electrode leads at the front and rear ends of the cell stack unit unit 100. The bus bar assembly 120 may include an inter bus bar 121 that electrically connects the battery cells, or a terminal bus bar 122 that may be connected to an external power source. The number of battery cells 110 stacked in one cell stack unit unit 100 may be, for example, 2, 4, 6, or 8, but is not limited thereto.

[0044] The cell stack unit 100 may include at least one buffer pad 130 between the stacked battery cells 110 (see FIG. 5(b)). The buffer pad is for absorbing the expansion of the battery cells 110 due to the swelling phenomenon.

[0045] In the present embodiment, a pouch-type battery cell is used as the battery cell 110, but this is not limited thereto. For example, the battery assembly may be formed using a can-type battery cell.

[0046] The pack housing 1100 of the present invention may include a unit frame assembly 200, and a front frame 300 and a rear frame 400 coupled to the front and rear ends of the unit frame assembly 200 in the front-rear direction, respectively.

[0047] The present invention is characterized in that it includes a plurality of unit frames 210 that support the bottom surface and one side surface of the battery assembly, and the unit frames are sequentially combined like Lego blocks to increase or decrease the bottom area of ​​the battery pack 1000 as needed. That is, the unit frame assembly 200 can function as a base plate and a partition wall of a conventional battery pack.

[0048] 6 and 7, the unit frame 210 includes a side wall 211 extending in a height direction and a base 212 extending from a lower end 211b of the side wall along one side (either left or right direction). The side wall 211 includes ends 211a and 211b at the top and bottom in the height direction. The base 212 extends to the left and right sides and includes both ends 212a and 212b in the horizontal direction. The right end 212b of the base 212 is connected to the lower end 211b of the side wall. The bases of the unit frames are sequentially coupled in a row along one side direction to form the unit frame assembly 200. That is, the end 212b of the lower end of the side wall of the base of one unit frame is sequentially coupled to the end 212a extending in one side direction of the following unit frame base, so that the unit frames 210 are coupled in a row along the horizontal direction (left and right direction) to form the unit frame assembly 200. The base portion 212 supports the lower surface of each battery assembly. Thus, the combined base portion forms a base plate of a conventional battery pack. By increasing or decreasing the number of unit frames 210 combined, the unit frame assembly 200 can become larger or smaller in the lateral direction. That is, the bottom area of ​​the battery pack 1000 constituted by the base portion can be changed as necessary.

[0049] In addition, the side wall 211 of the unit frame 210 functions like a partition wall that divides the battery modules in a conventional battery pack. That is, as shown in Fig. 7, the unit frames 210 are sequentially coupled in the horizontal direction, so that the side wall parts 211 of adjacent unit frames 210 are arranged to face each other. A battery assembly such as a battery module 10 or a cell stack unit 100 can be arranged in the space between the side wall parts 211 that are arranged to face each other. Therefore, by sequentially coupling the unit frames 210 in the horizontal direction, the area of ​​the bottom on which the battery assembly is placed increases, and the number of partition walls that divide the battery assemblies can naturally increase.

[0050] In this way, the size of the battery pack can be adjusted to meet a wide variety of required specifications by combining unit frames in a lateral direction with different numbers of units combined like Lego blocks. This allows the electric capacity of the battery pack to be freely adjusted to meet the required performance. Therefore, according to the present embodiment, the design freedom of the battery pack can be significantly increased.

[0051] 8 and 9, the battery assembly has a certain width in the cell stacking direction (parallel to the left-right direction) and a certain length extending long in the longitudinal direction (parallel to the front-rear direction). For example, each of the cell stack unit units 100 is accommodated in a space between adjacent unit frames 210 of the unit frame assembly 200. That is, the lower surface of each cell stack unit unit 100 is supported by the base portion 212 of each unit frame 210. Also, the cell stack unit unit 100 is accommodated in each unit frame 210 of the unit frame assembly 200 such that both widthwise side surfaces of the cell stack unit unit 100 are supported by the opposing side wall portions 211 of the adjacent unit frames 210.

[0052] 1 is applied as a battery assembly, the battery module 10 is accommodated in a space between adjacent unit frames 210. A lower surface of the battery module 10 (a lower surface of the lower housing 12B) is supported by a base portion 212 of each unit frame 210. The battery module 10 is accommodated in each unit frame 210 of the unit frame assembly 200 such that both widthwise side surfaces (both side surfaces of the lower housing 12B) of the battery module 10 are supported by opposing side wall portions 211 of the adjacent unit frames 210, respectively.

[0053] Meanwhile, the unit frame 210 extends to a certain length in the front-rear direction. That is, the side wall portion 211 and the base portion 212 extend in the front-rear direction. The front-rear length of the side wall portion and the base portion is determined to fully accommodate the front-rear length of the battery assembly. That is, the front-rear length of the unit frame 210 is determined by the length of the battery cells 110 constituting the battery assembly. Alternatively, as described below, when a plurality of battery assemblies 200 are arranged in a line in the front-rear direction, the length of the unit frame 210 may be correspondingly elongated in the front-rear direction. That is, the present invention has an advantage that not only the bottom size of the battery pack can be changed in the front-rear direction by increasing or decreasing the number of unit frames 210 combined in the front-rear direction, but also the bottom size of the battery pack can be increased in the front-rear direction by elongating the length of the unit frames 210 in the front-rear direction according to the length of the battery assembly or the number of battery assemblies arranged in the longitudinal direction.

[0054] 9, the side wall portion 211 of the unit frame 210 may be formed to be higher than the height of the battery assembly, for example, the cell stack unit 100. Thus, the side wall portion 211 may stably support the side of the battery assembly.

[0055] The side wall portion 211 and the base portion 212 may be manufactured by integral molding. Alternatively, the unit frame 210 may be manufactured by vertically arranging two flat plates so that one end of each plate contacts the other, and welding the ends of the contacting flat plates together.

[0056] The unit frame 210 may be manufactured as a hollow frame by extruding a metal material such as aluminum so that an empty space H, f1 is formed inside. By configuring the unit frame to be hollow in this manner, the weight of the battery pack may be reduced and the energy efficiency may be increased. In addition, by forming a rib-shaped partition wall in the internal space, the mechanical rigidity of the frame may be maintained at a reliable level. As described below, the hollow space formed in the unit frame 210 may also be used as a passage through which a cooling fluid passes or as a venting channel for venting gas generated in the battery pack.

[0057] The unit frames may be joined together by welding such as friction stir welding. In this case, a step P having a shape matching the shape of the front end 212a of the unit frame base part following the side wall part lower end 212b of the base part 212 of the unit frame 210 may be formed. That is, as shown in Figs. 7 and 9, the step P is provided at the side wall part lower end 212b of the base part (or the side wall part lower end 211b following the base part end). The step part shape is adapted to mesh with the shape of the front end 212a of the following unit frame base part. Therefore, the base parts 212 adjacent in the horizontal direction are joined to each other so as to mesh with each other at the step P, so that the joining strength of the unit frame 210 can be increased. In addition, since the joining surface of the step P and the base part can support the load of the side wall part 211 of the unit frame and the battery assembly in the height direction, there is an advantage that the load of the battery assembly can be suitably distributed.

[0058] 4 and 6, a front frame 300 is coupled to a front end in the front-rear direction of the unit frame assembly 200. Also, a rear frame 400 is coupled to a rear end in the front-rear direction of the unit frame assembly 200.

[0059] The front and rear frames cover the front and rear of the battery assembly and are coupled to the unit frame assembly 200. Thus, a storage space for the battery assembly is formed by the base part 212 of the unit frame, the opposing side walls 211 of the adjacent unit frames, the front frame 300, and the rear frame 400.

[0060] The front frame 300 may extend long in the left-right direction and stand upright in the height direction. The front frame may include a front cover part 310 extending in the height direction and a front plate part 320 protruding forward from a lower part of the front cover part 310. The front plate part 320 may be fixedly coupled to a structure such as a vehicle.

[0061] The rear frame 400 may be elongated in the left-right direction and erected in the height direction. The rear frame may have the same or different shape as the front frame. The rear frame includes a rear cover part 410 in the height direction and a rear plate part 420 protruding rearward from a lower part of the rear cover part, and has the same shape as the front frame. The rear plate part 420 may be fixedly coupled to a structure such as a vehicle.

[0062] The height of the front cover part and the rear cover part may be the same as the height of the side wall part 211 of the unit frame.

[0063] 6, the unit frame 210 at the forefront in one side direction of the unit frame assembly 200 is open at the end of the base part. Therefore, the battery assembly cannot be accommodated on the base part of the forefront unit frame. In this case, the base part of the forefront unit frame 210 may be used as a coupling part to be coupled to a structure such as a vehicle. In such an example, the left-right length of the front frame 300 and the rear frame 400 coupled to the unit frame assembly 200 may extend from the rearmost unit frame in one side direction to the side wall part of the foremost unit frame in one side direction.

[0064] However, the unit frame assembly 200 may further include, for example, a first side frame 500 coupled to a base portion of the forefront unit frame 210 so that the forefront unit frame 210 can also accommodate a battery assembly. The first side frame 500 may have a shape that extends long in the front-rear direction. The length of the first side frame 500 in the front-rear direction may be the same as the length of the unit frame 210 in the front-rear direction. Therefore, the first side frame 500 may be coupled to an end of the base portion of the forefront unit frame 210 to cover the forefront of one side of the unit frame assembly 200. Thus, a battery assembly may be additionally accommodated in a space formed by the first side frame 500 and the forefront unit frame 210. At this time, a lower surface of the battery assembly is supported by a base portion of the forefront unit frame 210, and both side surfaces are supported by the first side frame 500 and the side wall portion 211 of the forefront unit frame 210 facing the first side frame 500, respectively. In this case, the left-right lengths of the front frame 300 and the rear frame 400 may extend from the rearmost unit frame 210 in one side direction to the first side frame 500. As a result, an accommodation space for the most front battery assembly in one side direction is formed by the base part 212 of the most front unit frame 210, the first side frame 500, the front frame 300 and the rear frame 400. The height of the first side frame 500 may be the same as the heights of the front frame 300 and the rear frame 400.

[0065] In addition to the unit frame 210, the first side frame 500, the front frame 300 and the rear frame 400 may also be manufactured as hollow frames having spaces formed therein, which may further reduce the weight of the battery pack. Also, a rib-shaped partition wall may be formed in the internal space to maintain the mechanical rigidity of the frame at a reliable level.

[0066] In addition, the pack housing 1100 may further include a pack cover 600 that covers the battery assembly and is coupled to the unit frame assembly 200. As shown in Fig. 6, a lower edge of the pack cover 600 may be coupled to upper ends of the front frame 300, the rear frame 400, the first side frame 500 and the rearmost side wall portion 211 of the unit frame assembly 200, respectively.

[0067] 9, the base portion 212 of the unit frame 210 may have a cooling passage f1 therein. For example, when the base portion 212 is extruded, a space may be formed inside the base portion according to the direction of travel of the extruded member. The internal space may be partitioned into a plurality of hollow channels by partition walls such as ribs. A separate cooling passage may be installed in at least one of the hollow channels, or the hollow channel itself may be used as a cooling passage.

[0068] Therefore, the present invention can provide a unit frame assembly 200 having a cooling passage f1 extending in the front-rear direction along the base portion 212. The battery assembly can be effectively cooled by flowing a cooling fluid through the cooling passage f1. Also, by making the base portion of the unit frame 210 have an integrated cooling structure, it is not necessary to install a separate cooling plate on the base portion as in the conventional technology. As a result, the height of the battery pack 1000 can be reduced to provide a more compact battery pack.

[0069] 6, the front frame 300 and the rear frame 400 may each have cooling channels f2 and f3 communicating with the cooling channel of the base portion. In this case, one of the front frame and the rear frame may have a refrigerant inlet and a refrigerant outlet communicating with the cooling channel. Alternatively, one of the front frame and the rear frame may have a refrigerant inlet, and the other may have a refrigerant outlet. Thus, the battery pack of the present invention may have various cooling paths designed to connect the cooling channel f2 of the front frame 300, the cooling channel f1 of the unit frame assembly 200, and the cooling channel f3 of the rear frame.

[0070] A heat transfer member R may be provided between the battery assembly and the base 212. The heat transfer member R may include at least one of thermally conductive grease, thermally conductive adhesive, thermally conductive epoxy, and heat dissipation pads to improve heat transfer, but is not limited thereto. In addition, the heat transfer member R may be configured to have a certain degree of adhesive strength since it serves to fix the lower surface of the battery assembly to the base of the unit frame assembly 200. The heat transfer member R allows heat to be easily transferred to the base having a cooling channel, and heat dissipation of the battery pack may be effectively performed.

[0071] FIG. 10 is a schematic diagram showing a process in which a battery assembly is installed in a battery pack of the present invention, and FIG. 11 is a schematic diagram comparing a conventional battery pack with the battery pack of the present invention.

[0072] The distance between the side walls 211 of the adjacent unit frames of the unit frame assembly 200 may be smaller than the width of each battery assembly. For example, when a cell stack unit 100 is used as a battery assembly, the distance between the side walls 211 may be smaller than the width of the cell stack unit 100.

[0073] Therefore, in order to accommodate each of the cell stack unit units 100 in each of the unit frames 210, it is necessary to compress the cell stack unit unit 100 in the width direction (battery cell stacking direction) and sandwich it between the side wall parts 211 of the adjacent unit frames 210. In addition, when the cell stack unit unit 100 is compressed in the width direction, the buffer pad 130 is compressed, so that the cell stack unit unit 100 can be easily compressed.

[0074] On the other hand, when the battery module 10 is used as a battery assembly, the following problems may occur.

[0075] First, the manufacturing cost is high because a module housing, end plates, and various other auxiliary parts are required to construct a battery module.

[0076] 3(a), an assembly tolerance G is inevitably generated in order to install the battery module 10 between the partition walls 22 of the pack housing. Therefore, the number of battery cells installed in the battery pack may be reduced by the assembly tolerance and the housing thickness of the battery module, and the energy density of the battery pack may be reduced.

[0077] 3(b), when the module housing 12 is installed on the battery cell 11 and the base plate 23 of the pack housing, two layers of heat transfer members 1, 1' are required above and below the module housing for heat transfer efficiency. Also, the cooling plate 24 and the module housing 12 increase the space in the height direction of the battery pack, and the weight of the pack increases. This not only increases the manufacturing cost, but also further reduces the energy density due to the increased weight of the battery pack and the expansion of the installation space.

[0078] However, when the cell stack unit 100 is used as a battery assembly, the above-mentioned problems can be solved.

[0079] That is, when the cell stack unit is applied, a so-called cell-to-pack structure is formed in which the battery cells are directly accommodated in the pack housing without a module housing, so that the processes and costs associated with the production and assembly of module components can be eliminated.

[0080] In particular, it is possible to eliminate assembly tolerances required for module installation, make the space inside the pack more compact in the height direction, and reduce the weight of the battery pack, thereby further improving the energy density per unit space of the same battery pack.

[0081] As described above, according to the present invention, when the battery cells 110 are accommodated in the battery pack, there is no need to provide the assembly tolerance G that is required when using a conventional battery module. Also, as described above, the cell stack unit 100 can be compressed and inserted between the side walls of the opposing unit frames 210. This can save space in the battery pack in the left-right direction, allowing more battery cells 110 to be installed in the same space, thereby improving energy density.

[0082] Meanwhile, the horizontal length of the base portion 212 of the unit frame 210 may be determined within a range in which the distance between the side wall portions 211 of the adjacent unit frames 210 is smaller than the width of each cell stack unit unit 100. That is, the horizontal length of the base portion may be suitably determined in consideration of the insertion space of the cell stack unit unit 100.

[0083] As described above, the battery assembly of the present invention can be firmly fixed by having both sides sandwiched between the opposing sidewalls of the adjacent unit frames 210. Also, the battery assembly is fixed to the base of the unit frames 210 by a heat transfer member such as a heat conductive adhesive provided on the lower surface of the battery assembly. Therefore, according to the present invention, the battery assembly can be firmly connected to each unit frame 210 without a separate fastening member, which is advantageous in that the overall ease of assembly is improved.

[0084] FIG. 11 clearly shows the advantages of using the cell stack unit 100 as a battery assembly.

[0085] In FIG. 11(b), the cell stack unit 100 is directly accommodated in the pack housing without a module housing. Therefore, unlike the battery module in FIG. 11(a), there is no need to provide an assembly tolerance required when accommodating a module in a pack, and the width can be reduced by the thickness of the module housing. In addition, since there is no module housing and the heat transfer member R is sufficient at one location between the cell stack unit 100 and the base part 212, material can be saved, the cooling path can be simplified, and heat dissipation efficiency can be improved. In addition, since the base part 212 has an integrated cooling structure with a cooling flow path, a cooling plate is not required. In this way, when the cell stack unit 100 is applied as a battery assembly, space is saved not only in the left-right direction but also in the height direction. Therefore, compared with a conventional battery pack, more battery cells 110 can be accommodated in a space having the same volume, and the energy density is significantly improved.

[0086] Meanwhile, some of the unit frames included in the unit frame assembly 200 may house an electrical equipment assembly (not shown) without installing a battery assembly. The electrical equipment assembly may house a relay device, a current sensor, a fuse, a BMS, an MSD (Manual Service Disconnector), etc. Such an electrical equipment assembly may be packaged in the battery pack together with the battery assembly so as not to be exposed to the outside.

[0087] Second embodiment FIG. 12 is an exploded perspective view showing a battery pack according to another embodiment of the present invention, and FIG. 13 is a perspective view showing a modified example of a unit frame.

[0088] 12 further includes a second side frame 500' coupled to a side wall of the unit frame 210 at the rearmost end of the unit frame assembly 200 in one side direction in addition to the configuration of the embodiment of FIG.

[0089] 6, since the side wall portion 211 of the rearmost unit frame 210 is thin, a second side frame 500' that covers the right side of the battery pack is included. The length and height of the second side frame 500' may be the same as those of the first side frame 500. In this embodiment, since the side wall portion of the rearmost unit frame 210 and the second side frame 500' are combined to form the right side wall of the battery pack, the width of the second side frame 500' may be smaller than the width of the first side frame 500 by the thickness of the side wall portion.

[0090] In the embodiments of Figures 6 and 12, a first side frame 500 is provided that can cover one side of the battery assembly so that a battery assembly (e.g., a cell stack unit 100) can be accommodated in the unit frame 210 at the most distal end on one side of the unit frame assembly 200.

[0091] The left side of FIG. 13 illustrates a unit frame 210 having a second side wall portion 214 in a form in which the foremost unit frame 210 itself can accommodate the battery assembly instead of the first side frame. That is, the foremost unit frame 210 of this embodiment further has a second side wall portion 214 facing the side wall portion at an extension end portion in one lateral direction of the base portion 212. Therefore, unlike the subsequent unit frames 210, the foremost unit frame 210 has side walls 211 and 214 on both sides of the base portion. Thus, the battery assembly can be accommodated in the foremost unit frame 210 such that the lower surface of the battery assembly is supported by the base portion of the foremost unit frame 210 and both side surfaces are supported by the side wall portion 211 and the second side wall portion 214, respectively. Since the second side wall portion 214 forms the left side wall of the battery pack, the width of the second side wall portion may be greater than the width of the side wall portion of the other unit frames 210. For example, the width of the second side wall portion may be the same as the width of the first side frame.

[0092] 13 shows an example in which the width of the side wall of the rearmost unit frame 210 of the unit frame assembly 200 is made the same as the width of the first side frame. That is, in this example, the second side frame 500' is not joined to the side wall of the rearmost unit frame 210, and the width of the side wall of the rearmost unit frame 210 itself is made larger. Therefore, unlike a normal side wall, the side wall 216 of the rearmost unit frame is shown with a different reference numeral.

[0093] As described above, in this embodiment, it has been proposed that the unit frame 210 can be configured with three types of dedicated parts. That is, if the unit frame 210 is configured with three types of unit frames, namely, the unit frame T1 having a normal side wall portion and base portion, the most front unit frame T2 having the second side wall portion 214, and the most rear unit frame T3 having a wide side wall portion, these unit frames can be suitably combined to configure the unit frame assembly 200. In the case of this embodiment, since various types of unit frames can be standardized and manufactured in advance, for example, there is no need to separately connect the first side frame 500 to the most front unit frame.

[0094] Third embodiment FIG. 14 is a perspective view showing a battery pack according to another embodiment of the present invention, and FIG. 15 is a combined view of a unit frame and a battery assembly of the battery pack according to the embodiment of FIG.

[0095] In the embodiment of FIG. 14, a plurality of battery assemblies are arranged side by side in a plurality of rows along the lateral direction (left-right direction) and housed in each unit frame 220.

[0096] The embodiment of FIG. 14 illustrates a battery pack 2000 structure that can accommodate the above battery assemblies when arranged in two or more rows along the front-to-rear direction.

[0097] FIG. 15 illustrates, as an example of a unit frame 220 of such a battery pack structure, the shape of the unit frames 220 when arranged in two rows along the front-rear direction of the battery assembly.

[0098] Referring to FIG. 15, the side walls 221 of the unit frame 220 are spaced apart from each other at a predetermined interval along the front-rear direction, and two side walls 221A and 221B are arranged in a row. The base 222 extends from the lower end of each side wall in one direction and extends long along the front-rear direction. That is, in this embodiment, the number of side walls is the same as the number of rows of battery assemblies (e.g., cell stack unit 100). Therefore, the lower surfaces of the two rows of battery assemblies are supported by one base 222. One side of each row of battery assemblies is supported by two side walls 221A and 221B of the unit frame 220. When two unit frames 220 are combined in the horizontal direction as shown in FIG. 15, a space in which the two rows of battery assemblies are accommodated is formed between the side walls of the opposing unit frames 220. The width of the two rows of battery assemblies may be compressed as shown in FIG. 10 and inserted between the opposing side walls. Thus, the battery assemblies in each row are accommodated in the space such that the lower surfaces thereof are supported by one base portion 222 of the unit frames 220. In this case, both side surfaces of the units 100 in each row are supported by respective sidewall portions of the adjacent unit frames 220 that face each other and are arranged along the front-rear direction.

[0099] FIG. 14 shows that the battery assemblies arranged in two rows in the front-rear direction are again arranged in a row in the lateral direction and housed in each unit frame 220.

[0100] In this manner, by arranging the battery assemblies in rows and columns in the front-rear and lateral directions, the number of battery cells accommodated in the battery pack 2000 can be significantly increased. This allows a larger and larger capacity battery pack to be configured. Therefore, according to the present embodiment, the bottom area of ​​the battery pack can be further increased, thereby further increasing the design freedom of the battery pack.

[0101] Meanwhile, in this embodiment, the side walls 221A, 221B of each unit frame 220 are spaced apart at a predetermined interval S in the front-rear direction. This is for the following reasons: first, to separate the front and rear battery assemblies and prevent them from interfering with each other; and second, to separate the battery assemblies in the interval S between the spaced apart side walls 221A, 221B and to install a reinforcing member capable of reinforcing the structural rigidity of the battery pack.

[0102] When the unit frame 220 is elongated in the front-rear direction, the rigidity of the battery pack in the longitudinal direction is weakened. In particular, when the number of battery assemblies housed in the unit frame 220 is increased, the load received by the unit frame 220 in the longitudinal direction is also increased. Therefore, a reinforcing member is required to reinforce the rigidity of the unit frame 220 or the battery pack in the front-rear direction (longitudinal direction). Referring to FIG. 14, a center frame 250 as a reinforcing member extends laterally along the base portion of each unit frame 220 and is coupled to the unit frame assembly 200'. The center frame 250 naturally divides the front and rear battery assemblies. In addition, the center frame 250 crosses the base portion of the unit frame assembly 200' in the front-rear direction and is coupled to the space between the side wall portions 221A and 221B arranged in the front-rear direction. As a result, even if the unit frame assembly 200' is elongated in the front-rear direction, the center frame 250 reinforces the rigidity of the battery pack 2000 and can firmly support the battery assemblies.

[0103] FIG. 16 is a schematic diagram of a unit frame which is a component of a battery pack according to a modified example of the present invention.

[0104] 16 illustrates that the side walls 231 of the unit frame 230 are arranged in three rows 231A, 231B, and 231C at predetermined intervals along the front-rear direction. In this case, three rows of battery assemblies (e.g., cell stack units 100) can be installed in the unit frame 230 in the front-rear direction.

[0105] Therefore, the bottom area of ​​the unit frame assembly and the battery pack is further increased in the front-rear direction. In theory, there is no limit to the length of the unit frame 230 in the front-rear direction or the number of side walls arranged in the front-rear direction. However, the number of battery assemblies required is determined according to the installation space of the vehicle and the capacity of the battery pack required. Therefore, the set number of battery assemblies may be suitably divided into rows and columns along the lateral and front-rear directions of the battery pack. In the present invention, the unit frame is assembled along the lateral direction like Lego blocks, so that the bottom of the unit frame assembly or the battery pack can be easily changed according to the number of battery assemblies required in the lateral direction. In addition, the length of the unit frame in the front-rear direction may be increased according to the number of rows of battery assemblies required in the front-rear direction, and the number of side walls may be made to match the number of each row, as in the present embodiment.

[0106] As described above, according to the present invention, the bottom area of ​​a battery pack can be freely changed in response to a wide variety of required design standards, so that a highly versatile battery pack can be manufactured.

[0107] Meanwhile, in the unit frame 230 capable of arranging three rows of battery assemblies as shown in Fig. 16, two intervals S1 and S2 are formed between the side wall portions. Two center frames 250 can be arranged in these intervals. That is, even if the number of rows of battery assemblies increases in the front-rear direction, the rigidity of the battery pack can be reinforced by suitably arranging the center frames 250 on the base portions 232 in the intervals between the side wall portions.

[0108] The above description is merely illustrative of the technical idea of ​​the present invention, and a person having ordinary knowledge in the technical field to which the present invention belongs may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the drawings disclosed in the present invention are for the purpose of explanation, not for the purpose of limiting the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such drawings. The scope of protection of the present invention should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0109] 10: Battery module 100: Cell stack unit 110: Battery cell 120: Busbar assembly 121: Interbusbar 122: Terminal busbar 130: Buffer pad 200, 200': Unit frame assembly 210, 220, 230, T1, T2, T3: Unit frame 211, 221, 231: Side wall 212, 222, 232: Base section 250: Center frame 300: Front frame 400: Rear frame 500: 1st side frame 500': 2nd side frame 600: Pack cover 1100, 2100: Pack housing 1000, 2000: Battery pack

Claims

1. The battery pack includes a plurality of battery assemblies and a pack housing that houses the battery assemblies, the pack housing comprising: a unit frame assembly including a plurality of unit frames each having a side wall and a base extending in one direction from a lower end of the side wall, the unit frames being connected in a row in a horizontal direction by sequentially connecting an end of the base part of one unit frame at a lower end of the side wall to an end of the base part of the following unit frame extending in one direction; a front frame coupled to a front end of the unit frame assembly in a front-rear direction; a rear frame coupled to a rear end of the unit frame assembly in a front-rear direction, Each battery assembly is accommodated in each unit frame such that a lower surface of the battery assembly is supported by a base portion of the respective unit frame and both side surfaces of the battery assembly are supported by opposing side wall portions of an adjacent unit frame.

2. The battery pack according to claim 1 , wherein a height of the side wall portion is greater than a height of the battery assembly.

3. a step portion having a shape that matches the shape of a front end portion of a subsequent unit frame base portion is formed at an end portion of the base portion of the unit frame on the lower end side of the side wall portion; The battery pack of claim 1 , wherein a front end of a subsequent unit frame base part is coupled to the stepped part.

4. The battery pack of claim 1 , further comprising a first side frame coupled to a base portion of a most distal unit frame in one side direction of the unit frame assembly.

5. 5. The battery pack of claim 4, wherein a lower surface of the battery assembly accommodated in the frontmost unit frame is supported by a base portion of the frontmost unit frame and both side surfaces of the battery assembly are supported by the first side frame and a side wall portion of the frontmost unit frame facing the first side frame, respectively.

6. The battery pack of claim 4 , further comprising a second side frame coupled to a side wall portion of a rearmost unit frame in one lateral direction of the unit frame assembly.

7. The battery pack of claim 4 , wherein a width of a side wall portion of a rearmost unit frame in one side direction of the unit frame assembly is the same as a width of the first side frame.

8. The battery pack of claim 1 , wherein the unit frame assembly further includes a second side wall portion at an end portion of the base portion that is extended in one lateral direction and faces the side wall portion.

9. 9. The battery pack of claim 8, wherein the battery assembly accommodated in the most front unit frame in one direction has a lower surface supported by a base portion of the most front unit frame and both side surfaces supported by the side wall portion and the second side wall portion, respectively.

10. The battery pack according to claim 8 , wherein a width of the second side wall portion is greater than a width of a side wall portion of another unit frame.

11. The battery pack according to claim 1 , wherein a distance between opposing sidewall portions of adjacent unit frames of the unit frame assembly is smaller than a width of each of the battery assemblies.

12. 12. The battery pack according to claim 11, wherein the battery assembly includes at least one cushioning pad between stacked battery cells.

13. The battery pack according to claim 1 , further comprising a heat transfer member between the battery assembly and the base.

14. The battery pack according to claim 1 , wherein the base portion includes a cooling passage therein.

15. 15. The battery pack of claim 14, wherein the front frame and the rear frame each include a cooling passage that communicates with a cooling passage of the base portion.

16. Each unit frame has two or more side wall portions spaced apart from each other in a row along a front-rear direction, and a base portion extending in one direction from a lower end of each side wall portion and extending long along the front-rear direction, the plurality of battery assemblies are arranged in two or more rows along a front-rear direction corresponding to the number of the side wall portions; 2. The battery pack according to claim 1, wherein the battery assemblies in each row are housed in each unit frame such that a lower surface of the battery assemblies is supported by one base portion of each unit frame and both side surfaces are supported by respective side wall portions of adjacent unit frames facing each other and disposed along the front-rear direction.

17. the battery assemblies are divided into rows by being positioned at intervals between the side wall portions spaced apart in the front-rear direction, 17. The battery pack of claim 16, further comprising a center frame extending laterally along a base portion of each unit frame and coupled to the unit frame assembly.

18. The battery pack of claim 1 , wherein the pack housing further comprises a pack cover coupled to the unit frame assembly while covering the battery assembly.

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