Battery packs and electric vehicles

Abstract

To provide a battery pack and electric vehicle with a simple structure, high structural strength, and high energy density. [Solution] The battery pack includes a case and a battery module located inside the case, the battery module includes a battery unit and reinforcing members, the battery unit includes N single cells, at least some of the single cells in the battery unit are connected by M reinforcing members, the outer surface of a single cell includes a bottom surface facing the bottom surface inside the case, a top surface facing the top surface inside the case, and a side surface, the side surface includes a first side surface and two opposite second side surfaces, the area of ​​which is the largest of the side surfaces, the area of ​​the first side surface is larger than the area of ​​the bottom surface and larger than the area of ​​the top surface, the N single cells are arranged in order, and the second side surfaces of two adjacent single cells are placed facing each other. The reinforcing members are fixedly attached to the first side surface of each of the Q adjacent single cells, where Q is an integer satisfying N>Q≧2.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority of Chinese Patent Application No. 201911128539.4, titled "Battery Pack and Electric Vehicle", filed by BYD Company Limited on November 18, 2019, and all of its contents are incorporated herein by reference.

[0002] This application relates to the technical field of batteries, and particularly to battery packs and electric vehicles.

Background Art

[0003] Currently, the power battery packs applied to electric vehicles mainly include a pack body and a plurality of battery modules installed in the pack body. The battery module includes a battery array composed of a plurality of batteries arranged in sequence, side plates installed on both sides of the battery array, and end plates installed at both ends of the battery array. The side plates and end plates are connected by screws or tie rods or welding to achieve fixation to the battery array. After the battery module is assembled, it is installed in the pack body by fasteners such as screws, and generally, a reinforcing beam needs to be installed in the battery pack to improve the strength of the battery pack. Due to the addition of structural members such as end plates, side plates, reinforcing beams, and fasteners, the overall weight of the battery pack is large, and the utilization rate of the internal space of the pack body decreases, and its energy density cannot meet the user's demand for the cruising ability of the electric vehicle. Also, such a structure has a complicated assembly process. The assembly process is complex. First, the batteries need to be assembled into battery modules, and then the battery modules need to be installed in the pack body, so the costs such as labor and materials increase.

[0004] To solve the above problems, the conventional utility model CN201822274851.1 provides a battery module including a first battery block, a second battery block, and a liquid cooling plate, where both the first and second battery blocks contain multiple single cells arranged horizontally, and each single cell in the battery block is positioned horizontally (i.e., the two large faces opposite each other are arranged vertically). The liquid cooling plate is installed vertically between the first and second battery blocks, and the two sides of the liquid cooling plate are bonded to the first and second battery blocks with a thermally conductive adhesive. With this battery module, the assembly process is simplified because structural members for mounting and fixing the single cells are omitted, but the overall structural strength of such a battery module is low. Furthermore, in order to ensure the cooling effect of the liquid cooling plate, a housing cavity for containing the coolant is provided inside the liquid cooling plate, and the housing cavity needs to have a certain thickness. However, due to their low strength, liquid cooling plates of this type cannot withstand the excessive structural forces required to prevent short circuits in individual cells caused by breakage and leakage of coolant. Therefore, the liquid cooling plates cannot provide reinforcement and support to the battery module. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a battery pack and electric vehicle that have a simple structure, are easy to assemble, and possess high structural strength, high space utilization efficiency, and high energy density. [Means for solving the problem]

[0006] To solve the above technical problems, in one embodiment, the battery pack according to the embodiment of the present application is It includes a case having a bottom and a top surface inside, and a battery module located inside the case, The battery module includes a battery unit and reinforcing members, the battery unit includes N single cells, where N > 2 and is an integer, there are M reinforcing members, where M > 1 and is an integer, at least some of the single cells in the battery unit are connected by the M reinforcing members, one reinforcing member is fixedly attached to the first side of at least some of the Q adjacent single cells, where Q satisfies N > Q ≥ 2 and is an integer, The outer surface of the single cell includes a bottom surface facing the bottom surface inside the case, a top surface facing the top surface inside the case, and a side surface, the side surface including a first side surface and two opposite second side surfaces, the area of ​​which of the side surfaces is the largest, the area of ​​which is larger than the area of ​​the bottom surface of the single cell and larger than the area of ​​the top surface of the single cell, the N single cells are arranged in order, the second side surfaces of two adjacent single cells are placed facing each other, and the arrangement direction of the single cells is the first direction.

[0007] Preferably, the dimension of the reinforcing member along the second direction is D0, the second direction is perpendicular to the first direction, and the dimension of at least one cell connected to the reinforcing member among Q adjacent cells along the second direction is D1, where D0 and D1 satisfy 0.006 ≤ D0 / D1 ≤ 0.5, and D1 = 10 to 90 mm.

[0008] Preferably, 0.012 ≤ D0 / D1 ≤ 0.4.

[0009] Preferably, the number of cells connected to the reinforcing member among the Q adjacent cells is Q / 2 or more.

[0010] Preferably, the M reinforcing members connect N single cells to form a battery unit, and one of the reinforcing members is fixedly attached to the first side surface of each of the Q adjacent single cells.

[0011] Preferably, the length of the battery module along the first direction is 400 to 2500 mm, and the battery module abuts against and is supported by the bottom surface inside the case.

[0012] Preferably, the length of a reinforcing member attached to the first side surface of at least one cell unit along the first direction of projection onto the first side surface of the cell unit is S, and the length of the cell unit along the first direction is P, where S and P satisfy the condition S = 0.1P to 0.5P.

[0013] Preferably, the M reinforcing members are located on one side of the battery module and arranged sequentially along a predetermined direction, with the first reinforcing member fixedly attached to the first side surface of each of the 1st to Qth single cells, the second reinforcing member fixedly attached to the first side surface of each of the Qth to 2Q-1th single cells, the third reinforcing member fixedly attached to the first side surface of each of the 2Q-1th to 3Q-2nd single cells, and so on, by analogy, the Mth reinforcing member fixedly attached to the first side surface of each of the M×Q-(M-1)-(Q-1)th to M×Q-(M-1)th single cells.

[0014] Preferably, one of the reinforcing members is fixedly attached to the first side surface of each of the two adjacent single cells.

[0015] Preferably, the side surface includes two opposite first side surfaces, the M reinforcing members are distributed on both sides of the battery module, the reinforcing members located on one side of the battery module are fixedly attached to one first side surface of each of the Q adjacent single cells, and the reinforcing members located on the other side of the battery module are fixedly attached to the other first side surface of each of the Q adjacent single cells.

[0016] Preferably, a reinforcing member located on one side of the battery module is fixedly attached to at least a portion of the surface of one first side of each of the Q adjacent single cells, and a reinforcing member located on the other side of the battery module is fixedly attached to at least a portion of the surface of the other first side of each of the Q adjacent single cells.

[0017] Preferably, the reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of each of the 1st to Qth single cells is fixedly attached to one first side surface of each of the Qth to 2Q-1th single cells, and by analogy, the Mth reinforcing member is fixedly attached to one first side surface of each of the M×Q-(M-1)-(Q-1)th to M×Q-(M-1)th single cells, The first reinforcing member located on the other side of the battery module is fixed and attached to the other first side surface of each of the first to Q single cells, the second reinforcing member is fixed and attached to the other first side surface of each of the Q to 2Q-1 single cells, and by analogy, the Mth reinforcing member is fixed and attached to the other first side surface of each of the M×Q-(M-1)-(Q-1) to M×Q-(M-1) single cells.

[0018] Preferably, the reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of the battery module is fixedly attached to one first side surface of each of the 1st to Qth single cells, the first reinforcing member located on the other side of the battery module is fixedly attached to the other first side surface of each of the Qth to 2Q-1st single cells, the second reinforcing member located on one side of the battery module is fixedly attached to one first side surface of each of the 2Q-1st to 3Q-2nd single cells, and the other side of the battery module The second reinforcing member is fixed and attached to the other first side of each of the 3Q-2 to 4Q-3 single cells. By analogy, the Mth reinforcing member located on one side of the battery module is fixed and attached to the one first side of each of the 2×M×Q-(2M-1)-2(Q-1) to 2×M×Q-(2M-1)-(Q-1) single cells. The Mth reinforcing member located on the other side of the battery module is fixed and attached to the other first side of each of the 2×M×Q-(2M-1)-(Q-1) to 2×M×Q-(2M-1) single cells.

[0019] Preferably, the reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of each of the 1st to Qth single cells is fixedly attached, the second reinforcing member is fixedly attached to one of the first sides of each of the Q+1th to 2Qth single cells, and by analogy, the Mth reinforcing member is fixedly attached to one of the first sides of each of the M×Q-(Q-1)th to M×Qth single cells. The first reinforcing member located on the other side of the battery module is fixed and attached to the other first side of each of the second to Q+1 single cells, the second reinforcing member is fixed and attached to the other first side of each of the Q+2 to 2Q+1 single cells, and by analogy, the Mth reinforcing member is fixed and attached to the other first side of each of the M×Q-(Q-1)+1 to M×Q+1 single cells.

[0020] Preferably, an extension is provided at one end of the reinforcing member, and the extension is attached to the top or bottom surface of at least one single cell.

[0021] Preferably, extensions are provided at both ends opposite to the reinforcing member, with one extension being attached to the top surface of at least one single cell and the other extension being attached to the bottom surface of at least one single cell.

[0022] Preferably, the case has X, Y, and Z directions perpendicular to each other, a plurality of battery modules are installed, the plurality of battery modules are arranged within the case along the X direction, the N single cells are arranged sequentially along the Y direction, the top and bottom surfaces of the single cells are positioned opposite each other along the Z direction, and the first direction is parallel to the Y direction.

[0023] Preferably, the single cell is a substantially rectangular parallelepiped, having a length L, a width H, and a thickness D, wherein the length L of the single cell is greater than or equal to the width H, and the width H of the single cell is greater than the thickness D, where the X direction is the thickness direction of the single cell, the Y direction is either the length direction or the width direction of the single cell, and the Z direction is the other of the length direction or the width direction of the single cell.

[0024] Preferably, the single cell includes six surfaces: a bottom surface, a top surface, two first sides, and two second sides, where the two first sides are opposite each other along the thickness direction, the two second sides are opposite each other along the length direction, and the bottom and top surfaces are opposite each other along the width direction.

[0025] Preferably, the case includes a first frame and a second frame that are oppositely installed along the Y direction, the battery module is installed between the first frame and the second frame, one end of the battery module is supported by the first frame, and the other end of the battery module is supported by the second frame.

[0026] Preferably, the reinforcing member is fixed and attached to the first side surface of each of Q adjacent single cells by a structural adhesive.

[0027] Preferably, the structural adhesive is a structural adhesive having thermal conductivity.

[0028] Preferably, the reinforcing member is a reinforcing plate.

[0029] Preferably, the reinforcing plate is a steel plate, an aluminum plate or a glass fiber plate.

[0030] Preferably, a plurality of the battery modules are installed, and there is a gap between two adjacent battery modules.

[0031] Preferably, the second side surfaces of two adjacent single cells in the battery unit are bonded to each other.

[0032] Preferably, a plurality of the battery modules are installed, and a reinforcing member is installed between at least two adjacent battery modules.

[0033] Preferably, the reinforcing member is fixed and attached to the battery modules located on both sides of the reinforcing member.

[0034] Preferably, the reinforcing member is an aluminum plate or a steel plate.

[0035] Preferably, the case includes a tray and an upper cover that together define a housing space, the battery module is located within the housing space, and the single cells in the battery module are fixedly attached with their top surfaces to the inner surface of the upper cover and their bottom surfaces to the inner surface of the tray.

[0036] Preferably, the tray and / or the upper cover have a multilayer composite structure.

[0037] Preferably, the multilayer composite structure includes two layers of aluminum plates and a steel plate or foamed aluminum plate sandwiched between the two layers of aluminum plates.

[0038] Preferably, the multilayer composite structure includes two fiber composite layers and a foamed material layer sandwiched between the two fiber composite layers.

[0039] Preferably, the fiber composite layer includes a glass fiber layer and / or a carbon fiber layer.

[0040] Preferably, multiple battery modules are installed, and the second sides of two adjacent single cells in one battery module are bonded together, with the bonded position being referred to as the first position; and the second sides of two adjacent single cells in another adjacent battery module are bonded together, with the bonded position being referred to as the second position; and the first and second positions are spaced apart along the first direction.

[0041] Preferably, multiple battery modules are installed, where two adjacent single cells in one battery module are separated by a first section, and two adjacent single cells in another adjacent battery module are separated by a second section, and the projection of the first section in the first direction does not overlap with the projection of the second section in the first direction.

[0042] Preferably, the number of cells in two adjacent battery modules are different, one battery module is denoted as the first battery module and the other as the second battery module, the number of cells in the first battery module is greater than the number of cells in the second battery module, and reinforcing blocks connected to the cells in the second battery module are installed.

[0043] In other embodiments, the electric vehicle according to the embodiment of the present application includes the battery pack described above. [Effects of the Invention]

[0044] According to the battery pack and electric vehicle embodiment of the present application, the reinforcing members are fixedly attached to the first side surface of at least some of the Q adjacent single cells, and by analogy, at least some of the single cells in the battery module can be integrally connected by M reinforcing members, and of the side, top, and bottom surfaces of a single cell, the area of ​​the first side surface is relatively large (i.e., the first side surface is the surface with the largest area), and in this way, the bonding area between the reinforcing member and the single cell can be guaranteed, which helps to guarantee the bonding strength between the two. In conventional patents, single cells have their larger surfaces facing the top and bottom surfaces of the case, i.e., they are arranged horizontally. Single cells are arranged sequentially along the horizontal direction to form a battery block. When the battery block is subjected to a vertical force, the battery module deforms along the vertical direction due to the vertical force. In other words, it is necessary to thicken the bottom of the case or install reinforcing ribs on the bottom of the case to ensure that the case has a certain structural strength. However, this reduces the gravimetric energy density or volumetric energy density of the battery pack. In this invention, the single cell has its top surface facing the top surface inside the case and its bottom surface facing the bottom surface inside the case; that is, the single cell is positioned upright inside the case, and the reinforcing member is also positioned upright. When a battery module is subjected to a vertical force, it is prone to deformation along the horizontal direction due to that vertical force, but the peripheral wall around the case can limit the occurrence of such deformation. Furthermore, the reinforcing member can integrally connect at least some of the single cells in the battery module, and the reinforcing and supporting action of the reinforcing member can improve the overall strength of the battery module. Since the battery module can act as a reinforcing beam inside the case, there is no need to separately install a reinforcing beam inside the case (in the prior art, the thickness of a reinforcing beam installed inside the case is at least tens of millimeters), and in this way the structure of the case can be greatly simplified, which helps to improve the space utilization rate of the battery pack. Moreover, the reinforcing member in this invention ensures that the battery module has sufficient strength, and because its thickness is relatively small, it helps to reduce the weight of the battery pack, which helps to improve the energy density of the battery pack.Furthermore, the battery modules are directly positioned and arranged within the case. This structural design eliminates the need for structural components to mount and secure individual cells, which not only helps reduce the overall weight of the battery pack but also simplifies the assembly process and helps lower production costs. [Brief explanation of the drawing]

[0045] [Figure 1] This is a schematic diagram of the battery pack according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of a battery module according to an embodiment of the present invention. [Figure 3] Figure 2 is an exploded view. [Figure 4] This is a plan view of Figure 2. [Figure 5] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 6] Figure 5 is an exploded view. [Figure 7] This is a schematic diagram of a battery module according to an embodiment of the present invention. [Figure 8] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 9] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 10] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 11] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 12] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 13] This is a plan view of a battery module according to an embodiment of the present invention. [Figure 14] This is a schematic diagram of a battery module according to an embodiment of the present invention. [Figure 15] This is a schematic diagram of a battery module according to an embodiment of the present invention. [Figure 16] This is a schematic diagram of the single cell according to an embodiment of the present invention. [Figure 17]This is a schematic diagram of a case relating to an embodiment of the present application. [Figure 18] This is a schematic diagram of a battery module according to an embodiment of the present invention. [Figure 19] This is another schematic diagram of the battery pack according to an embodiment of the present invention. [Modes for carrying out the invention]

[0046] The embodiments of the present application will be described in detail below, and examples of the above embodiments are shown in the drawings. Throughout, the same or similar reference numerals indicate the same or similar parts or parts having the same or similar function. The embodiments described below with reference to the drawings are illustrative only and are for interpreting the present application, and should not be understood as limiting the present application.

[0047] As shown in Figures 1 to 19, an embodiment of the present invention provides a battery pack 10 including a case 100 having a bottom surface and a top surface inside, and a battery module 200 located inside the case 100. The battery module 200 includes a battery unit 201 and reinforcing members 300, the battery unit 201 includes N single cells 202, where N>2 and is an integer, and the reinforcing members 300 consist of M members, where M>1 and is an integer. At least some of the individual cells 202 in the battery unit 201 are connected by M reinforcing members 300, and the outer surface of each individual cell 202 includes a bottom surface 206 facing the bottom surface inside the case 100, a top surface 205 facing the top surface inside the case 100, and sides, the sides include a first side surface 203 and two opposite second side surfaces 204, the area of ​​which is largest is the first side surface 203, the area of ​​which is larger than the area of ​​the bottom surface 206 of the individual cell 202 and larger than the area of ​​the top surface 205 of the individual cell 202, the N individual cells 202 are arranged in sequence, the second side surfaces 204 of two adjacent individual cells 202 are placed facing each other, and the arrangement direction of the individual cells 202 is the first direction. One reinforcing member 300 is fixedly attached to the first side surface 203 of at least some of the Q adjacent cell cells 202, such that Q is an integer and N > Q ≥ 2.

[0048] For example, one reinforcing member 300 may be fixed and attached to the first side surface 203 of one of three adjacent cell cells 202, but not to the first side surfaces 203 of the other two cell cells 202. Alternatively, one reinforcing member 300 may be fixed and attached to the first side surfaces 203 of two of the three adjacent cell cells 202, but not to the first side surface 203 of the other cell cell 202.

[0049] Alternatively, for example, one reinforcing member 300 may be fixedly attached to the first side surface 203 of one of the four adjacent single cells 202, but not attached to the first side surfaces 203 of the other three single cells 202. Or, one reinforcing member 300 may be fixedly attached to the first side surfaces 203 of two of the four adjacent single cells 202, but not attached to the first side surfaces 203 of the other two single cells 202.

[0050] Furthermore, the shape, dimensions, and structure of the second side surface 204 located on the two opposite sides of the single cell 202 may be the same or different. The first side surface 203 may be the entire surface of the first side surface 203 or a part of the surface of the first side surface 203. In the battery pack 10 according to the embodiment of the present application, the reinforcing member 300 is fixedly attached to the first side surface 203 of at least some of the Q adjacent single cells 202. By analogy, at least some of the single cells 202 in the battery module 200 can be integrally connected by M reinforcing members 300. Of the side, top, and bottom surfaces of the single cell 202, the area of ​​the first side surface 203 is relatively large (i.e., the first side surface 203 is the surface with a large area). In this way, the bonding area between the reinforcing member 300 and the single cell 202 can be guaranteed, which helps to guarantee the bonding strength between the two. In conventional patents, the single cell 202 has its larger surface facing the top and bottom surfaces of the case, i.e., it is arranged horizontally. When a battery block formed by arranging the single cells 202 sequentially along the horizontal direction is subjected to a vertical force, the battery module 200 is prone to deformation along the vertical direction due to this vertical force. Therefore, to ensure that the case has a certain structural strength, it is necessary to thicken the bottom of the case or install reinforcing ribs on the bottom of the case. However, this reduces the gravimetric energy density or volumetric energy density of the battery pack 10. In the present application, the single cell 202 has its top surface facing the top surface inside the case and its bottom surface facing the bottom surface inside the case, i.e., the single cell 202 is arranged upright inside the case, and the reinforcing members are also arranged upright. When the battery module 200 is subjected to a vertical force, it is prone to deformation along the horizontal direction due to this vertical force, but the peripheral wall around the case can limit the occurrence of such deformation. Furthermore, the reinforcing member allows at least some of the individual cells 202 in the battery module 200 to be connected together, and the reinforcing and supporting action of the reinforcing member improves the overall strength of the battery module 200.Since the battery module 200 can act as a reinforcing beam within the case, there is no need to separately install a reinforcing beam within the case (in the prior art, the thickness of a reinforcing beam installed within the case is at least several tens of millimeters). In this way, the structure of the case can be greatly simplified, which helps to improve the space utilization rate of the battery pack 10. Furthermore, the reinforcing member in this application ensures that the battery module 200 has sufficient strength, and because its thickness is relatively small, only a few millimeters, it helps to reduce the weight of the battery pack 10, which helps to improve the energy density of the battery pack 10. In addition, the battery module 200 is directly placed and arranged within the case, and this structural design eliminates the need for structural members to mount and fix the individual cells 202, which not only helps to reduce the overall weight of the battery pack 10 but also simplifies the assembly process and helps to reduce production costs.

[0051] In this specification, the case 100 of the battery pack 10 may be understood as a case for housing battery modules 200, and may include a tray 101 and an upper cover (not shown), the tray 101 and the upper cover together define a housing space for housing battery modules 200. For example, the tray and the upper cover are sealed together to form the housing space. The battery modules 200 are installed on the tray 101 and covered by the upper cover. The number of battery modules 200 in the case 100 may be set according to actual needs, for example, two or three. The battery pack 10 includes at least one of a battery management system (BMS), a battery connector, a battery sampler, and a battery thermal management system.

[0052] In one embodiment, the dimension of the reinforcing member 300 along the second direction is D0, the second direction is perpendicular to the first direction, and the weight of one of the single cells 202 fixedly attached to the reinforcing member 300 is G. D0 and G satisfy 0.15 mm·kg-1 < D0 / G < 7 mm·kg-1, and D0 = 0.5 to 5 mm. By installing in this way, not only can it be ensured that the battery module 200 has sufficient strength, but also the thickness of the reinforcing member 300 can be reduced, the weight of the battery pack 10 can be reduced, and it helps to improve the energy density of the battery pack 10.

[0053] Furthermore, 0.25 mm·kg-1 ≤ D0 / G ≤ 5.8 mm·kg-1. By installing in this way, the strength of the battery module can be further improved, the thickness of the reinforcing member 300 can be reduced, the weight of the battery pack 10 can be reduced, and it helps to improve the energy density of the battery pack 10.

[0054] In an embodiment, the dimension of the reinforcing member along the second direction is D0, and the second direction is perpendicular to the first direction. The dimension of one of the Q adjacent single cells 202 connected to the reinforcing member 300 along the second direction is D1. D0 and D1 satisfy 0.006 ≤ D0 / D1 ≤ 0.5, and D1 = 10 to 90 mm. By installing in this way, not only can it be avoided that the thickness of the single cell 202 is too large, but also a high adhesion strength between the reinforcing member 300 and the single cell 202 can be ensured.

[0055] Furthermore, 0.012 ≤ D0 / D1 ≤ 0.4, whereby the thickness of the single cell 202 is not too large, and a higher adhesion strength between the single cell 202 and the reinforcing member 300 can be ensured.

[0056] In the embodiment, the number of cell units 202 connected to the reinforcing member 300 out of Q adjacent cell units 202 is Q / 2 or greater. For example, the number of cell units 202 connected to the reinforcing member 300 out of three adjacent cell units 202 is two or three. The number of cell units 202 connected to the reinforcing member 300 out of four adjacent cell units 202 is two, three, or four.

[0057] In one embodiment, M reinforcing members 300 connect N single cells 202 to form a battery unit 201, and one reinforcing member 300 is fixedly attached to the first side surface 203 of each of the Q adjacent single cells 202.

[0058] Each reinforcing member 300 is fixed and attached to the first side surface 203 of each of the Q adjacent single cells 202. By analogy, M reinforcing members 300 can be used to integrally connect N single cells 202 in the battery unit 201, thereby further improving the overall strength of the battery module 200. Since the battery module 200 can act as a reinforcing beam within the case 100, the structure of the case 100 can be greatly simplified, and the space occupied by reinforcing ribs can be reduced, which helps to improve the space utilization rate and energy density of the battery pack 10. Furthermore, the battery module 200 is directly positioned and arranged within the case 100. This structural design eliminates the need for structural members to mount and fix the single cells 202, which not only helps to reduce the overall weight of the battery pack 10 but also simplifies the assembly process and helps to reduce production costs.

[0059] In one embodiment, the length of the battery module 200 along the first direction is 400 to 2500 mm, and the battery module 200 is in contact with and supported by the bottom surface inside the case 100.

[0060] The reinforcing member 300 allows the individual cells 202 in the battery module 200 to be connected integrally, and the reinforcing and supporting action of the reinforcing member 300 improves the overall strength of the battery module 200. Since the battery module 200 can act as a reinforcing beam within the case 100, the structure of the case 100 can be greatly simplified and the space occupied by reinforcing ribs can be reduced, which helps to improve the space utilization rate and energy density of the battery pack 10. Furthermore, since the battery module 200 is directly placed and arranged within the case 100, this structural design eliminates the need for structural members to mount and fix the individual cells 202, which not only helps to reduce the overall weight of the battery pack 10 but also simplifies the assembly process and helps to reduce production costs.

[0061] Furthermore, the length of the battery module 200 along the first direction is 600 to 2500 mm to meet the demands of use.

[0062] In one embodiment, the battery unit 201 includes four single cells 202. Naturally, the number of single cells 202 included in the battery unit 201 may be set according to actual needs, for example, three or five or more.

[0063] In one embodiment, as shown in Figure 2, one reinforcing member 300 is fixedly attached to the first side surface 203 of each of two adjacent single cells 202.

[0064] In another embodiment, as shown in Figure 8, one reinforcing member 300 is fixedly attached to the first side surface 203 of each of the three adjacent single cells 202.

[0065] In one embodiment, the reinforcing member 300 is fixedly attached to at least a portion of the first side surface 203 of each of the Q adjacent cell cells 202.

[0066] As shown in Figure 2, the reinforcing member 300 is fixedly attached to at least a portion of the surface of the first side surface 203 of each of the two adjacent single cells 202. The reinforcing member 300 is fixedly attached to a portion of the surface of the first side surface 203 of the two adjacent single cells 202. Naturally, the reinforcing member 300 may be fixedly attached to the entire surface of the first side surface 203 of one single cell 202 and to a portion of the surface of the first side surface 203 of the other single cell 202.

[0067] However, in another embodiment, as shown in Figure 8, the reinforcing member 300 is fixedly attached to at least a portion of the surface of the first side surface 203 of each of the three adjacent single cells 202. The reinforcing member 300 is fixedly attached to a portion of the surface of the first side surface 203 of two of the three adjacent single cells 202 and to the entire surface of the first side surface 203 of one of the single cells 202. Naturally, the reinforcing member 300 may also be fixedly attached to a portion of the surface of the first side surface 203 of the three adjacent single cells 202.

[0068] In one embodiment, as shown in Figures 2 and 8, the M reinforcing members 300 are located on one side of the battery module 200 and are arranged sequentially along a predetermined direction. The first reinforcing member 300 is fixedly attached to the first side surface 203 of each of the 1st to Qth single cells 202, the second reinforcing member 300 is fixedly attached to the first side surface 203 of each of the Qth to 2Q-1th single cells 202, the third reinforcing member 300 is fixedly attached to the first side surface 203 of each of the 2Q-1st to 3Q-2nd single cells 202, and so on. By analogy, the Mth reinforcing member 300 is fixedly attached to the first side surface 203 of each of the M×Q-(M-1)-(Q-1)th to M×Q-(M-1)th single cells 202.

[0069] The predetermined direction may be parallel to the first direction, or it may be at a certain angle to the first direction.

[0070] As shown in Figure 2, the battery unit 201 includes four single cells 202, and three reinforcing members 300 are located on one side of the battery module 200. Each reinforcing member 300 is fixedly attached to the first side surface 203 of each of two adjacent single cells 202. The first reinforcing member 300 is fixedly attached to the first side surface 203 of each of the first to second single cells 202, the second reinforcing member 300 is fixedly attached to the first side surface 203 of each of the second to third single cells 202, and the third reinforcing member 300 is fixedly attached to the first side surface 203 of each of the third to fourth single cells 202.

[0071] As shown in Figure 8, the battery unit 201 includes five single cells 202, and two reinforcing members 300 are located on one side of the battery module 200. Each reinforcing member 300 is fixedly attached to the first side surface 203 of each of the three adjacent single cells 202. The first reinforcing member 300 is fixedly attached to the first side surface 203 of each of the first to third single cells 202, and the second reinforcing member 300 is fixedly attached to the first side surface 203 of each of the third to fifth single cells 202.

[0072] In one embodiment, as shown in Figures 6 and 7, the side surface includes two opposite first side surfaces 203, and M reinforcing members 300 are distributed on both sides of the battery module 200. The reinforcing members 300 located on one side of the battery module 200 are fixedly attached to one first side surface 203 of each of the Q adjacent single cells 202, and the reinforcing members 300 located on the other side of the battery module 200 are fixedly attached to the other first side surface 203 of each of the Q adjacent single cells 202, thereby further improving the strength of the battery unit 201. The number of Q is not specifically limited and may be two, three or more.

[0073] Furthermore, the fact that the reinforcing member 300 located on one side of the battery module 200 is fixed and attached to one first side surface 203 of each of the Q adjacent single cells 202 may be understood as the reinforcing member 300 being fixed and attached to the entire surface or a portion of the surface of one first side surface 203 of each of the Q adjacent single cells 202. Similarly, the fact that the reinforcing member 300 located on the other side of the battery module 200 is fixed and attached to the other first side surface 203 of each of the Q adjacent single cells 202 may be understood as the reinforcing member 300 being fixed and attached to the entire surface or a portion of the surface of the other first side surface 203 of each of the Q adjacent single cells 202.

[0074] In one embodiment, a reinforcing member 300 located on one side of the battery module 200 is fixedly attached to at least a portion of the surface of one first side surface 203 of each of the Q adjacent single cells 202, and a reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to at least a portion of the surface of the other first side surface 203 of each of the Q adjacent single cells 202.

[0075] As shown in Figure 6, the reinforcing member 300 located on one side of the battery module 200 is fixedly attached to at least a portion of the surface of one first side surface 203 of each of the two adjacent single cells 202. The reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to at least a portion of the surface of the other first side surface 203 of each of the two adjacent single cells 202.

[0076] However, in another embodiment, as shown in Figure 9, a reinforcing member 300 located on one side of the battery module 200 is fixedly attached to at least a portion of the surface of one first side surface 203 of each of the three adjacent single cells 202. A reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to at least a portion of the surface of the other first side surface 203 of each of the three adjacent single cells 202.

[0077] As shown in Figures 5, 6, and 9, the reinforcing members 300 located on both sides of the battery module 200 are arranged sequentially along a predetermined direction, the first reinforcing member 300 located on one side of one of the first to Q single cells 202 is fixed and attached to the first side surface 203 of each single cell 202 from the 1st to Qth single cells 202, the second reinforcing member 300 is fixed and attached to one of the first side surface 203 of each single cell 202 from the Qth to 2Q-1th single cells 202, and by analogy, the Mth reinforcing member 300 is fixed and attached to one of the first side surface 203 of each single cell 202 from the M×Q-(M-1)-(Q-1)th to M×Q-(M-1)th single cells 202, The first reinforcing member 300, located on the other side of the battery module 200, is fixedly attached to the other first side surface 203 of each of the first to Q single cells 202, the second reinforcing member 300 is fixedly attached to the other first side surface 203 of each of the Q to 2Q-1 single cells 202, and by analogy, the Mth reinforcing member 300 is fixedly attached to the other first side surface 203 of each of the M×Q-(M-1)-(Q-1) to M×Q-(M-1) single cells 202.

[0078] In this embodiment, as shown in Figures 5 and 6, the battery unit 201 includes four single cells 202. Three reinforcing members 300 are located on one side of the battery module 200, and each reinforcing member 300 is fixedly attached to one first side surface 203 of each of two adjacent single cells 202. Three reinforcing members 300 are located on the other side of the battery module 200, and each reinforcing member 300 is fixedly attached to the other first side surface 203 of each of two adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each single cell 202 of the first to second single cells, the second reinforcing member 300 is fixedly attached to one first side surface 203 of each single cell 202 of the second to third single cells 202, and the third reinforcing member 300 is fixedly attached to one first side surface 203 of each single cell 202 of the third to fourth single cells 202. The first reinforcing member 300, located on the other side of the battery module 200, is fixedly attached to the other first side surface 203 of each single cell 202 among the first to second single cells; the second reinforcing member 300 is fixedly attached to the other first side surface 203 of each single cell 202 among the second to third single cells 202; and the third reinforcing member 300 is fixedly attached to the other first side surface 203 of each single cell 202 among the third to fourth single cells 202.

[0079] However, in another embodiment, as shown in Figure 9, the battery unit 201 includes five single cells 202. Two reinforcing members 300 are located on one side of the battery module 200, and each reinforcing member 300 is fixedly attached to one first side surface 203 of each of the three adjacent single cells 202. Two reinforcing members 300 are located on the other side of the battery module 200, and each reinforcing member 300 is fixedly attached to the other first side surface 203 of each of the three adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the first to third single cells 202, the second reinforcing member 300 is fixedly attached to one first side surface 203 of each of the third to fifth single cells 202, the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each of the first to third single cells 202, and the second reinforcing member 300 is fixedly attached to the other first side surface 203 of each of the third to fifth single cells 202.

[0080] As shown in Figures 10 and 11, the reinforcing members 300 located on both sides of the battery module 200 are arranged sequentially along a predetermined direction, the first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the 1st to Qth single cells 202, the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each of the Qth to 2Q-1th single cells 202, and the second reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the 2Q-1st to 3Q-2nd single cells 202, and the battery module The second reinforcing member 300 on the other side of the 200 is fixed and attached to the other first side surface 203 of each of the 3Q-2nd to 4Q-3rd single cells 202. By analogy, the Mth reinforcing member 300 located on one side of the battery module 200 is fixed and attached to the one first side surface 203 of each of the 2×M×Q-(2M-1)-2(Q-1)th to 2×M×Q-(2M-1)-(Q-1)th single cells 202. The Mth reinforcing member 300 located on the other side of the battery module 200 is fixed and attached to the other first side surface 203 of each of the 2×M×Q-(2M-1)-(Q-1)th to 2×M×Q-(2M-1)th single cells 202.

[0081] In this embodiment, as shown in Figure 10, the battery unit 201 includes five single cells 202. Two reinforcing members 300 are located on one side of the battery module 200, and each reinforcing member 300 is fixedly attached to one first side surface 203 of each of two adjacent single cells 202. Two reinforcing members 300 are located on the other side of the battery module 200, and each reinforcing member 300 is fixedly attached to the other first side surface 203 of each of two adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the first to second single cells 202, and the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each of the second to third single cells 202. A second reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the third and fourth single cells 202, and a second reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each of the fourth and fifth single cells 202.

[0082] However, in another embodiment, as shown in Figure 11, the battery unit 201 includes seven single cells 202, and two reinforcing members 300 are located on one side of the battery module 200, with each reinforcing member 300 fixedly attached to one first side surface 203 of each of the three adjacent single cells 202. One reinforcing member 300 is located on the other side of the battery module 200, and this reinforcing member 300 is fixedly attached to the other first side surface 203 of each of the three adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each of the first to third single cells 202, and the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each of the third to fifth single cells 202. The second reinforcing member 300, located on one side of the battery module 200, is fixed and attached to one of the first sides 203 of each of the fifth to seventh single cells 202.

[0083] As shown in Figures 12 and 13, the reinforcing members 300 located on both sides of the battery module 200 are arranged sequentially along a predetermined direction, the first reinforcing member 300 located on one side of one of the first to Q single cells 202 is fixed and attached to the first side 203 of each single cell 202 among the 1st to Qth single cells 202, the second reinforcing member 300 is fixed and attached to one of the first side 203 of each single cell 202 among the Q+1th to 2Qth single cells 202, and by analogy, the Mth reinforcing member 300 is fixed and attached to one of the first side 203 of each single cell 202 among the M×Q-(Q-1)th to M×Qth single cells 202, The first reinforcing member 300, located on the other side of the battery module 200, is fixed and attached to the other first side surface 203 of each of the second to Q+1th single cells 202; the second reinforcing member 300 is fixed and attached to the other first side surface 203 of each of the Q+2th to 2Q+1th single cells 202; and by analogy, the Mth reinforcing member 300 is fixed and attached to the other first side surface 203 of each of the M×Q-(Q-1)+1th to M×Q+1th single cells 202.

[0084] In this embodiment, as shown in Figure 12, the battery unit 201 includes five single cells 202, and two reinforcing members 300 are located on one side of the battery module 200, with each reinforcing member 300 fixedly attached to one first side surface 203 of each of two adjacent single cells 202. Two other reinforcing members 300 are located on the other side of the battery module 200, with each reinforcing member 300 fixedly attached to the other first side surface 203 of each of two adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each single cell 202 among the first to second single cells, the second reinforcing member 300 is fixedly attached to one first side surface 203 of each single cell 202 among the third to fourth single cells 202, the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each single cell 202 among the second to third single cells 202, and the second reinforcing member 300 is fixedly attached to the other first side surface 203 of each single cell 202 among the fourth to fifth single cells 202.

[0085] However, in another embodiment, as shown in Figure 13, the battery unit 201 includes four single cells 202, and two reinforcing members 300 are located on one side of the battery module 200, with each reinforcing member 300 fixedly attached to one first side surface 203 of each of two adjacent single cells 202. One reinforcing member 300 is located on the other side of the battery module 200, and this reinforcing member 300 is fixedly attached to the other first side surface 203 of each of two adjacent single cells 202. The first reinforcing member 300 located on one side of the battery module 200 is fixedly attached to one first side surface 203 of each single cell 202 among the first to second single cells, the second reinforcing member 300 is fixedly attached to one first side surface 203 of each single cell 202 among the third to fourth single cells 202, and the first reinforcing member 300 located on the other side of the battery module 200 is fixedly attached to the other first side surface 203 of each single cell 202 among the second to third single cells 202.

[0086] In one embodiment, as shown in Figures 2 and 14, an extension portion 400 is installed at one end of the reinforcing member 300, and the extension portion 400 is attached to the top surface 205 or bottom surface 206 of at least one single cell 202, thereby further improving the strength of the battery unit 201. For example, the extension portion 400 may be attached to the top surface 205 or bottom surface 206 of one single cell 202, or it may be attached to the top surface 205 or bottom surface 206 of one single cell 202.

[0087] In this embodiment, the reinforcing member 300 is integrally molded with the extension portion 400. Naturally, the reinforcing member 300 and the extension portion 400 may be manufactured separately and then joined together.

[0088] In one embodiment, as shown in Figures 2 and 15, extensions 400 are installed at both ends opposite to the reinforcing member 300, with one extension 400 attached to the top surface 205 of at least one single cell 202 and the other extension 400 attached to the bottom surface 206 of at least one single cell 202, thereby further improving the strength of the battery unit 201. For example, one extension 400 is attached to the top surface 205 of one single cell 202, and the other extension 400 is attached to the bottom surface 206 of one single cell 202. Alternatively, one extension 400 is attached to the top surfaces 205 of two single cells 202, and the other extension 400 is attached to the bottom surfaces 206 of two single cells 202.

[0089] In one embodiment, as shown in Figures 1 and 2, the case 100 has X, Y, and Z directions perpendicular to each other, a plurality of battery modules 200 are installed, the plurality of battery modules 200 are arranged in the case 100 along the X direction, N single cells 202 are arranged sequentially along the Y direction, the top surface 205 and bottom surface 206 of the single cells 202 are located on opposite sides along the Z direction, the first direction is parallel to the Y direction, and the second direction is parallel to the X direction.

[0090] In one embodiment, as shown in Figures 2, 16, and 17, the cell 202 is a roughly rectangular parallelepiped with length L, width H, and thickness D, where the length L of the cell 202 is greater than or equal to the width H, and the width H of the cell 202 is greater than the thickness D, where the X direction is the thickness direction of the cell 202, the Y direction is either the length direction or the width direction of the cell 202, and the Z direction is the other of the length direction or the width direction of the cell 202. The dimension of the cell 202 along the second direction is the thickness of the cell 202, i.e., D1 = D.

[0091] Furthermore, the description of the cell 202 as substantially rectangular in shape in this specification may be understood to mean that the cell 202 may be rectangular or cubic in shape, may have localized irregularities but be substantially rectangular or cubic, or may have notches, protrusions, chamfers, curves, and bends in some parts but be substantially rectangular or cubic in overall shape.

[0092] Each cell 202 has six surfaces: a bottom surface 206, a top surface 205, two first sides 203, and two second sides 204, the two first sides 203 being opposite each other along the thickness direction, the two second sides 204 being opposite each other along the length direction, and the bottom surface 206 and top surface 205 being opposite each other along the width direction.

[0093] The case 100 includes a first frame 102 and a second frame 103 that are installed opposite each other along the Y direction. The battery module 200 is installed between the first frame 102 and the second frame 103, with one end of the battery module 200 supported by the first frame 102 and the other end supported by the second frame 103. In other words, the battery module 200 extends from the first frame 102 to the second frame 103 along the Y direction. To put it another way, the battery module 200 extends from one side of the case 100 to the other along the Y direction, and one battery module 200 is installed within the case 100 along the Y direction.

[0094] By fixing and attaching the reinforcing member 300 to the first side surface 203 of the single cell 202, the single cell 202 is integrally connected, and the overall strength of the battery module 200 can be improved by the reinforcing and supporting action of the reinforcing member 300. Since the battery module 200 can act as a reinforcing beam within the case 100, the structure of the case can be greatly simplified and the space occupied by reinforcing ribs can be reduced, which helps to improve the space utilization rate and energy density of the battery pack 10. Furthermore, since the battery module 200 is directly placed and arranged within the case 100, this structural design eliminates the need for structural members to mount and fix the single cell 202, which not only helps to reduce the overall weight of the battery pack 10 but also simplifies the assembly process and helps to reduce production costs.

[0095] In this embodiment, one end of the battery module 200 may be directly or indirectly supported by the first frame 102, and the other end of the battery module 200 may be directly or indirectly supported by the second frame 103. Direct means that one end of the battery module 200 is directly in contact with and fitted and supported by the first frame 102, and the other end of the battery module 200 is directly in contact with and fitted and supported by the second frame 103. Indirect means, for example, in some embodiments, that one end of the battery module 200 is fitted and supported by the first frame 102 by an intermediate member, and the other end of the battery module 200 is fitted and supported by the second frame 103 by an intermediate member. Furthermore, both ends of the battery module 200 may be fixed to the first frame 102 and the second frame 103, and specific fixing methods will be described in detail below. This application does not limit itself to specific support and fixing methods.

[0096] In the technical concept of the present invention, in one embodiment, the distance between the first frame 102 and the second frame 103 along the Y direction is matched with the dimensions of the battery module 200, where matching means that one battery module 200 can be fitted and installed in the space between the two frames, and in order to achieve the objective of the present invention, such fitting may be a combination of various methods such as gap fitting, interlocking fitting, fastening fitting, and fixed fitting.

[0097] Furthermore, the case 100 further includes a third frame 104 and a fourth frame 105 installed opposite each other along the X direction, and the multiple battery modules 200 are arranged in parallel between the third frame 104 and the fourth frame 105 along the X direction.

[0098] The case 100 includes a tray 101 and an upper cover that together define a storage space. The battery module 200 is located within this storage space, and the individual cells 202 in the battery module 200 are fixedly attached to the inner surface of the upper cover with their top surfaces and to the inner surface of the tray 101 with their bottom surfaces. This allows the battery module 200, the upper cover, and the tray 101 to form an integrated structure, which has high mechanical strength. In other words, the battery pack 10 has high structural strength and can withstand external impacts well. Because the battery pack 10 has sufficient structural strength during use, it can be considered part of the overall structural strength of the vehicle. In other words, contrary to conventional design philosophies, there is no need to design separate structural members to protect the battery pack 10 throughout the entire vehicle. The battery pack 10 improves the overall structural strength of the vehicle. Using such a design simplifies and even eliminates the design structure for protecting the structural strength of the battery pack 10 within the vehicle's frame, thereby achieving the design requirement for overall vehicle weight reduction, reducing overall vehicle design and manufacturing costs, and improving overall vehicle production efficiency.

[0099] The inner surface of the upper cover refers to the surface of the upper cover closest to the single cell 202, and the inner surface of the tray 101 refers to the surface of the tray 101 closest to the single cell 202. The top surface of the single cell 202 in the battery module 200 may be directly fixed and attached to the inner surface of the upper cover, or it may be indirectly fixed and attached to the inner surface of the upper cover. For example, the top surface of the single cell 202 in the battery module 200 may be fixed and attached to one side of the connection plate, and the other side of the connection plate may be fixed and attached to the inner surface of the upper cover. Similarly, the bottom surface of the single cell 202 in the battery module 200 may be directly fixed and attached to the inner surface of the tray 101, or it may be indirectly fixed and attached to the inner surface of the tray 101. For example, the bottom surface of the single cell 202 in the battery module 200 may be fixed and attached to one side of the connection plate, and the other side of the connection plate may be fixed and attached to the inner surface of the tray 101.

[0100] In this embodiment, the tray 101 includes a first frame 102 and a second frame 103 installed opposite each other along the Y direction, and a third frame 104 and a fourth frame 105 installed opposite each other along the X direction.

[0101] In one embodiment, to form the case 100 into a rectangle or square, the first frame 102 and the second frame 103 are connected perpendicularly to the third frame 104 and the fourth frame 105. In another embodiment, to form the case 100 into a trapezoid, parallelogram, or the like, the first frame 102 and the second frame 103 may be parallel to each other, and the third frame 104 and the fourth frame 105 may be installed at an angle to the first frame 102 and the second frame 103. This application does not limit the specific shape of the case 100 composed of the first frame 102, the second frame 103, the third frame 104 and the fourth frame 105.

[0102] In some embodiments of the present application, the third frame 104 applies a force toward the fourth frame 105 to a battery module 200 installed adjacent to the third frame 104, and the fourth frame 105 applies a force toward the third frame 104 to a battery module 200 installed adjacent to the fourth frame 105, thereby enabling multiple battery modules 200 to be densely arranged between the third frame 104 and the fourth frame 105 along the X direction, and enabling multiple battery modules 200 to be bonded to one another. Furthermore, the third frame 104 and the fourth frame 105 can restrict the position of multiple battery modules 200 in the X direction, and in particular, when a battery module 200 expands slightly, they act as buffers and provide inward pressure to the battery module 200, preventing the amount of expansion and deformation of the battery module 200 from becoming too large.

[0103] To further improve the structural strength of the battery pack 10, the upper cover has a multilayer composite structure. The multilayer composite structure includes two layers of aluminum plates and a steel plate sandwiched between the two layers of aluminum plates, or the multilayer composite structure includes two layers of aluminum plates and a foamed aluminum plate sandwiched between the two layers of aluminum plates, or the multilayer composite structure includes two fiber composite layers and a foamed material layer sandwiched between the two fiber composite layers. The fiber composite layers include a glass fiber layer and / or a carbon fiber layer.

[0104] To further improve the structural strength of the battery pack 10, the tray 101 is also a multilayer composite structure. The multilayer composite structure includes two layers of aluminum plates and a steel plate sandwiched between the two layers of aluminum plates, or the multilayer composite structure includes two layers of aluminum plates and a foamed aluminum plate sandwiched between the two layers of aluminum plates, or the multilayer composite structure includes two fiber composite layers and a foamed material layer sandwiched between the two fiber composite layers. The fiber composite layers include a glass fiber layer and / or a carbon fiber layer.

[0105] In one embodiment, the reinforcing member 300 is a reinforcing plate, and the dimension of the reinforcing member 300 along the second direction is the thickness of the reinforcing plate. Note that the reinforcing member 300 is not limited to a plate-like structure and may have other shapes, and reinforcing ribs may be added to the plate-like structure to further improve strength.

[0106] Furthermore, the reinforcing plate is made of steel, aluminum, or glass fiber.

[0107] In one embodiment, as shown in Figures 2 and 3, the reinforcing member 300 is fixedly attached to the first side surface 203 of each of the Q adjacent cell cells 202 using structural adhesive 500. Here, the number of Q is not specifically limited and may be, for example, three or four.

[0108] Furthermore, the structural adhesive 500 is a thermally conductive structural adhesive 500. The thermally conductive structural adhesive 500 not only ensures a high bonding effect between the reinforcing member 300 and the first side surface 203 of the cell 202, but can also conduct the heat generated during the operation of the cell 202.

[0109] As shown in Figures 2 to 4, the length of the reinforcing member 300 attached to the first side surface 203 of at least one single cell 202 along the first direction of projection onto the first side surface 203 of the single cell 202 is S, and the length of the single cell 202 along the first direction is P, where S and P satisfy the condition S = 0.1P to 0.5P. By setting it in this way, a high adhesive effect between the reinforcing member 300 and the first side surface 203 of the single cell 202 can be guaranteed. Furthermore, it can be guaranteed that there is a certain distance W between each of the two adjacent reinforcing members 300, and this distance W can buffer the expansion of the single cell 202 during operation. In this way, there is no need to leave a gap between adjacent battery modules 200 in advance, which helps to improve the space utilization rate of the battery pack 10.

[0110] The first direction is parallel to the Y direction. The length P along the first direction of cell 202 is the length L of cell 202.

[0111] In this embodiment, the battery unit 201 includes four single cells 202, and the length of the reinforcing member 300 along the first direction of projection of each single cell 202 onto the first side surface 203 is S. Naturally, depending on the actual requirements, the length of only one single cell 202 or only two single cells 202 along the first direction of projection onto the first side surface 203 may be S.

[0112] In one embodiment, there is a gap between two adjacent battery modules 200, which allows for expansion that occurs during the operation of a single cell 202. The gap may also function as a cooling air passage, or a liquid cooling plate may be installed in the gap, in order to cool and dissipate heat from the single cell 202.

[0113] In one embodiment, to meet actual usage needs, the battery unit 201 is connected in series, in parallel, or in series-parallel, and the individual cells 202 in the battery unit 201 are connected in series, in parallel, or in series-parallel.

[0114] In one embodiment, as shown in Figures 1 and 2, the battery pack 10 further includes a power connection member 600, and the individual cells 202 in the battery unit 201 are connected in series or in parallel by the power connection member 600.

[0115] Furthermore, in order to easily place the battery module 200 inside the case 100, the electrode terminals 207 of the single cell 202 are placed on the top surface 205 of the single cell 202. Two electrode terminals 207 are provided for the single cell 202, one of which is the positive terminal and the other is the negative terminal.

[0116] In one embodiment, multiple battery modules 200 are installed, and reinforcing members are installed between at least two adjacent battery modules 200. By installing them in this manner, the strength of the battery modules 200 can be further improved by the reinforcing members, and the structural strength of the battery pack 10 can be further improved. The number of battery modules 200 may be set according to the actual needs, for example, two, three, or four. For example, three battery modules 200 are installed, and a reinforcing member is installed between the first battery module 200 and the second battery module 200 along the direction of arrangement of the battery modules 200, or between the second battery module 200 and the third battery module 200 along the direction of arrangement of the battery modules 200, or between the first battery module 200 and the second battery module 200, and between the second battery module 200 and the third battery module 200. Furthermore, the reinforcing members are fixedly attached to the battery modules 200 located on both sides of the reinforcing members. Structural adhesive is firmly attached to both sides of the reinforcing members. Structural adhesives not only guarantee high bonding strength between the two materials, but they can also perform a thermal conductivity function.

[0117] Furthermore, the reinforcing member is a reinforcing plate, which has a solid structure and is, for example, a solid aluminum plate or steel plate.

[0118] In one embodiment, multiple battery modules 200 are installed, and two adjacent single cells 202 in one battery module 200 are installed separated by a first section, and two adjacent single cells 202 in another adjacent battery module 200 are installed separated by a second section, and the projection of the first section in a first direction and the projection of the second section in a first direction do not overlap. The size of the first section and the size of the second section may be the same or different. With this arrangement, the position of relatively low structural strength in one battery module (i.e., the position in the first section) and the position of relatively low structural strength in an adjacent battery module (i.e., the position in the second section) can be offset from each other, thus enabling the position of relatively low structural strength in one battery module to be compensated for by the adjacent battery module, which helps to improve the overall strength of the battery pack.

[0119] For example, in one battery module 200, the first and second single cells 202 arranged along a first direction are separated by a first section, and in another battery module 200 adjacent to the first battery module 200, the first and second single cells 202 arranged along a first direction are separated by a second section, and the projection of the first section in the first direction does not overlap with the projection of the second section in the first direction. Alternatively, in one battery module 200, the second and third single cells 202 arranged along a first direction are separated by a first section, and in another battery module 200 adjacent to the first battery module 200, the second and third single cells 202 arranged along a first direction are separated by a second section, and the projection of the first section in the first direction does not overlap with the projection of the second section in the first direction.

[0120] In some embodiments, as shown in Figures 2, 18, and 19, multiple battery modules 200 are installed, and the second sides 204 of two adjacent single cells 202 in one battery module 200 are bonded together, with the bonded position designated as the first position. The second sides 204 of two adjacent single cells 202 in another adjacent battery module 200 are also bonded together, with the bonded position designated as the second position. The first and second positions are spaced apart along the first direction. As can be understood, this arrangement helps to improve the overall strength of the battery pack 10 by offsetting the relatively low structural strength of two adjacent battery modules 200, i.e., the first and second positions are offset from each other. In addition, because the second sides 204 of two adjacent single cells 202 in the battery module 200 are bonded together, it helps to reduce the space occupied by the battery pack 10 and improves the volume utilization rate of the battery pack 10.

[0121] For example, in one battery module 200, the second side 204 of the first cell 202 and the second side 204 of the second cell 202, which are arranged along a first direction, are bonded together, and this bonded position is denoted as the first position. In another battery module 200 adjacent to the battery module 200, the second side 204 of the first cell 202 and the second side 204 of the second cell 202, which are arranged along a first direction, are bonded together, and this bonded position is denoted as the second position. The first position and the second position are spaced apart along the first direction. Alternatively, in one battery module 200, the second side 204 of a second cell 202 and the second side 204 of a third cell 202, arranged along a first direction, are bonded together, and the bonded position is denoted as the first position; and in another battery module 200 adjacent to the battery module 200, the second side 204 of a second cell 202 and the second side 204 of a third cell 202, arranged along a first direction, are bonded together, and the bonded position is denoted as the second position; and the first position and the second position are spaced apart along the first direction.

[0122] Furthermore, the number of individual cells 202 in two adjacent battery modules 200 differs, with one battery module 200 being referred to as the first battery module and the other as the second battery module. The number of individual cells 202 in the first battery module is greater than the number of individual cells 202 in the second battery module, and reinforcing blocks 700 connected to the individual cells 202 in the second battery module are installed. To make it clear, after the individual cells 202 in the two adjacent battery modules 200 are arranged in the above arrangement, a gap is formed at a certain position in the battery unit 201 of the second battery module. In this case, a reinforcing block 700 is installed in the gap, and the reinforcing block 700 is connected to the individual cells 202. In this way, the strength of the battery module 200 can be further improved, and the overall strength of the battery pack 10 can also be improved. For example, a gap is formed at one or both ends along the first direction of the battery unit of the second battery module, or a gap is formed in the middle of the battery unit of the second battery module. In this case, a reinforcing block is installed in the gap. The reinforcing block may be fixed and attached to the second side of the single cell, or the reinforcing block may be fixed and attached to the reinforcing member, and the reinforcing member may be fixed and attached to the first side of the single cell.

[0123] For example, the first battery module has four single cells 202, the second battery module has three single cells 202, and reinforcing blocks 700 are installed at one or both ends of the battery unit 201 of the second battery module along the first direction. Alternatively, the first battery module has three single cells 202, the second battery module has two single cells 202, and reinforcing blocks 700 are installed at one or both ends of the battery unit 201 of the second battery module along the first direction.

[0124] Furthermore, the dimensions of the first battery module along the first direction are the same as the dimensions of the second battery module along the first direction, and the first and second battery modules are arranged alternately in the X direction within the case 100. This arrangement not only facilitates the arrangement of the battery modules 200 within the case 100 but also improves the space utilization rate of the battery pack 10.

[0125] In the above embodiment, a structural adhesive is used to bond the individual cells 202 together and between the individual cells 202 and the case 100, so that the inside of the battery pack 10 is firmly and integrally formed. Preferably, bonding is done by adhesive injection, which helps to improve the overall strength of the battery pack.

[0126] In another embodiment, the present invention further provides an electric vehicle including the battery pack 10. The battery pack 10 has high structural strength, and the battery pack 10 of this structure is installed at the bottom of the vehicle, providing good support for the overall structural strength of the vehicle, which can facilitate the overall strength design of the vehicle, thereby reducing the overall design cost and difficulty of the vehicle and shortening the cycle. (Specific examples 1-14)

[0127] Four rectangular prism-shaped single cells 202 are arranged along the Y direction in the manner shown in Figure 2 and connected by three reinforcing members 300, each reinforcing member 300 being connected to two single cells 202 and located on one side of the battery module 200. The shape of the reinforcing members 300 is flat, as shown in Figure 2. These four single cells 202 are assembled into one battery module 200, and twelve such battery modules 200 are arranged and placed along the X direction on a tray 101 as shown in Figure 17. Both ends of each battery module 200 are supported by a first frame 102 and a second frame 103, and then sealed with an upper cover to form a battery pack. The reinforcing members 300 and single cells 202 in each embodiment satisfy Table 1, and the test results based on GB / T 31467.3-2015 "Lithium-ion power storage battery packs and systems for electric vehicles Part 3: Safety requirements and test methods" are shown in Table 1.

[0128] Table 1 Test results of vibration and pressure resistance performance of battery packs including battery modules from Examples 1 to 14 [Table 1] (Specific examples 15-28)

[0129] Four rectangular prism-shaped single cells 202 are arranged along the Y direction in the manner shown in Figure 7 and connected by three reinforcing members 300. Two reinforcing members 300 are installed on one side of the battery module 200 and one reinforcing member 300 is installed on the other side of the battery module 200. Each reinforcing member 300 is connected to two single cells 202, and the shape of the reinforcing members 300 is flat as shown in Figure 7. These four single cells 202 are assembled into one battery module 200, and twelve such battery modules 200 are arranged and placed along the X direction in a tray 101 as shown in Figure 17. Both ends of each battery module 200 are supported by a first frame 102 and a second frame 103, and then sealed with an upper cover to form a battery pack. The reinforcing member 300 and the single cell 202 in each embodiment satisfy Table 2, and the test results based on GB / T 31467.3-2015 "Lithium-ion power storage battery packs and systems for electric vehicles, Part 3: Safety requirements and test methods" are shown in Table 2.

[0130] Table 2 Test results of vibration and pressure resistance performance of battery packs including battery modules from Examples 15-28 [Table 2]

[0131] Furthermore, in the description of this application, the directions or positional relationships indicated by terms such as "center," "vertical direction," "horizontal direction," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are based on the directions or positional relationships shown in the drawings and are merely for the purpose of easily explaining and simplifying the description of this application. They do not indicate or suggest that the shown device or component has a specific direction or must be configured and operate in a specific direction, and therefore should not be understood as limiting this application.

[0132] Furthermore, the terms “first” and “second” are merely for explanatory purposes and should not be understood as indicating or suggesting relative importance, or implicitly indicating the number of technical features shown. Thus, features limited by “first” and “second” may explicitly or implicitly include at least one such feature. In this description, “multiple” means at least two, for example, two, three, etc., unless otherwise clearly and specifically limited.

[0133] In this application, unless otherwise clearly specified or limited, terms such as "attachment," "connection," "connection," and "fixing" should be understood in a broad sense. For example, unless otherwise clearly specified, a connection may be fixed, detachable, integral, mechanical, electrical, direct, indirect via an intermediate medium, or an internal communication between two parts or an interaction between two parts. A person skilled in the art will be able to understand the specific meaning of the above terms in this application depending on the specific situation.

[0134] In this application, unless otherwise clearly specified or limited, the presence of a first feature "above" or "below" a second feature may mean that the first and second features are in direct contact, or that they are indirectly in contact via an intermediate medium. Furthermore, the presence of a first feature "above," "above," and "on the top surface" of a second feature may mean that the first feature is directly above or diagonally above the second feature, and may only indicate that the horizontal height of the first feature is higher than that of the second feature. The presence of a first feature "below," "below," and "on the bottom surface" of a second feature may mean that the first feature is directly below or diagonally below the second feature, and may only indicate that the horizontal height of the first feature is lower than that of the second feature.

[0135] In this specification, any reference to terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” means that the specific features, structures, materials, or properties described in combination with such embodiment or example are included in at least one embodiment or example of this application. In this specification, illustrative descriptions of the above terms are not necessarily limited to the same embodiment or example. The specific features, structures, materials, or properties described can be appropriately combined in any one or more embodiments or examples. Furthermore, a person skilled in the art can combine and combine different embodiments or examples and features described herein, provided they are not contradictory.

[0136] Although embodiments of the present application have been shown and described above, it should be understood that these embodiments are illustrative and should not be understood as limiting the present application. Those skilled in the art can modify, alter, substitute, and transform these embodiments within the scope of the present application. [Explanation of symbols]

[0137] 10. Battery pack; 100. Case; 101. Tray; 102. First frame; 103. Second frame; 104. Third frame; 105. Fourth frame; 200. Battery module; 201. Battery unit; 202. Single cell; 203. First side; 204. Second side; 205. Top surface; 206. Bottom surface; 207. Electrode terminals; 300. Reinforcement member; 400. Extended part; 500. Structural adhesive; 600. Power connection member; 700. Reinforcement block.

Claims

1. It includes a case having a bottom surface and a top surface, and a battery module located inside the case, The battery module includes a battery unit and reinforcing members, the battery unit includes N single cells, where N is an integer greater than 2, there are M reinforcing members, where M is an integer greater than 1, at least some of the single cells in the battery unit are connected by the M reinforcing members, one reinforcing member is fixedly attached to the first side of at least some of the Q adjacent single cells, where Q is an integer and N > Q ≥ 2. The battery pack is characterized in that the outer surface of the single cell includes a bottom surface facing the bottom surface of the case, a top surface facing the top surface of the case, and a side surface, the side surface includes a first side surface and two second side surfaces located on opposite sides, the area of ​​the first side surface is the largest of the side surfaces, the area of ​​the first side surface is larger than the area of ​​the bottom surface of the single cell and larger than the area of ​​the top surface of the single cell, the N single cells are arranged in order, the second side surfaces of two adjacent single cells are placed facing each other, and the arrangement direction of the single cells is the first direction.

2. The battery pack according to claim 1, characterized in that the dimension of the reinforcing member along the second direction is D0, the second direction is perpendicular to the first direction, and the dimension of one of the Q adjacent single cells connected to the reinforcing member along the second direction is D1, and D0 and D1 satisfy 0.006 ≤ D0 / D1 ≤ 0.5, and D1 = 10 to 90 mm.

3. The battery pack according to claim 2, characterized in that 0.012 ≤ D0 / D1 ≤ 0.

4.

4. The battery pack according to any one of claims 1 to 3, characterized in that the number of single cells connected to the reinforcing member among the Q adjacent single cells is Q / 2 or more.

5. The battery pack according to any one of claims 1 to 4, characterized in that the M reinforcing members connect N single cells to form a battery unit, and one of the reinforcing members is fixedly attached to the first side surface of each of the Q adjacent single cells.

6. The battery pack according to any one of claims 1 to 5, characterized in that the length of the battery module along the first direction is 400 to 2500 mm, and the battery module abuts against and is supported by the bottom surface inside the case.

7. The battery pack according to any one of claims 1 to 6, characterized in that the length of a reinforcing member attached to the first side surface of at least one single cell along the first direction of projection onto the first side surface of the single cell is S, and the length of the single cell along the first direction is P, where S and P satisfy the condition S = 0.1P to 0.5P.

8. The battery pack according to any one of claims 1 to 7, characterized in that the M reinforcing members are located on one side of the battery module and are arranged sequentially along a predetermined direction, the first reinforcing member is fixedly attached to the first side surface of each of the first to Q single cells, the second reinforcing member is fixedly attached to the first side surface of each of the Q to 2Q-1 single cells, the third reinforcing member is fixedly attached to the first side surface of each of the 2Q-1 to 3Q-2 single cells, and similarly the M reinforcing member is fixedly attached to the first side surface of each of the M×Q-(M-1)-(Q-1) to M×Q-(M-1) single cells.

9. The battery pack according to any one of claims 1 to 8, characterized in that one of the reinforcing members is fixedly attached to the first side surface of two adjacent single cells.

10. The battery pack according to any one of claims 1 to 9, wherein the side surface includes two opposite first side surfaces, the M reinforcing members are distributed to both sides of the battery module, the reinforcing members located on one side of the battery module are fixedly attached to one first side surface of each of the Q adjacent single cells, and the reinforcing members located on the other side of the battery module are fixedly attached to the other first side surface of each of the Q adjacent single cells.

11. The battery pack according to claim 10, wherein a reinforcing member located on one side of the battery module is fixedly attached to at least a portion of the surface of one first side of each of the Q adjacent single cells, and a reinforcing member located on the other side of the battery module is fixedly attached to at least a portion of the surface of the other first side of each of the Q adjacent single cells.

12. The reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of each of the first to Q single cells is fixedly attached, the second reinforcing member is fixedly attached to one of the first sides of each of the Q to 2Q-1 single cells, and similarly, the Mth reinforcing member is fixedly attached to one of the first sides of each of the M×Q-(M-1)-(Q-1) to M×Q-(M-1) single cells. The battery pack according to claim 10 or 11, characterized in that the first reinforcing member located on the other side of the battery module is fixedly attached to the other first side surface of each of the first to Q single cells, the second reinforcing member is fixedly attached to the other first side surface of each of the Q to 2Q-1 single cells, and by analogy, the Mth reinforcing member is fixedly attached to the other first side surface of each of the M×Q-(M-1)-(Q-1) to M×Q-(M-1) single cells.

13. The reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of the battery module is fixedly attached to one first side surface of each of the 1st to Qth single cells, the first reinforcing member located on the other side of the battery module is fixedly attached to the other first side surface of each of the Qth to 2Q-1st single cells, the second reinforcing member on one side of the battery module is fixedly attached to one first side surface of each of the 2Q-1st to 3Q-2nd single cells, and the second reinforcing member on the other side of the battery module is fixed to the 3Q-2nd to 4Q - The battery pack according to any one of claims 10 to 12, characterized in that the M-th reinforcing member located on one side of the battery module is fixedly attached to the first side of the other side of each of the third single cell, and by analogy, the M-th reinforcing member located on one side of the battery module is fixedly attached to the first side of each of the 2×M×Q-(2M-1)-2(Q-1)-th to 2×M×Q-(2M-1)-(Q-1)-th single cells, and the M-th reinforcing member located on the other side of the battery module is fixedly attached to the first side of the other side of each of the 2×M×Q-(2M-1)-(Q-1)-th to 2×M×Q-(2M-1)-th single cells.

14. The reinforcing members located on both sides of the battery module are arranged sequentially along a predetermined direction, the first reinforcing member located on one side of each of the first to Q single cells is fixedly attached, the second reinforcing member is fixedly attached to one of the first sides of each of the Q+1 to 2Q single cells, and similarly, the Mth reinforcing member is fixedly attached to one of the first sides of each of the M×Q-(Q-1) to M×Q single cells. The battery pack according to any one of claims 10 to 13, characterized in that the first reinforcing member located on the other side of the battery module is fixedly attached to the other first side surface of each of the second to Q+1 single cells, the second reinforcing member is fixedly attached to the other first side surface of each of the Q+2 to 2Q+1 single cells, and similarly the Mth reinforcing member is fixedly attached to the other first side surface of each of the M×Q-(Q-1)+1 to M×Q+1 single cells.

15. The battery pack according to any one of claims 1 to 14, characterized in that an extended portion is provided at one end of the reinforcing member, and the extended portion is attached to the top or bottom surface of each cell.

16. The battery pack according to any one of claims 1 to 15, characterized in that extensions are provided at both ends located on the opposite side of the reinforcing member, one of the extensions is attached to the top surface of each cell, and the other extension is attached to the bottom surface of each cell.

17. The battery pack according to any one of claims 1 to 16, characterized in that the case has X, Y, and Z directions perpendicular to each other, a plurality of battery modules are installed, the plurality of battery modules are arranged in the case along the X direction, N single cells are arranged sequentially along the Y direction, the top and bottom surfaces of the single cells are installed on opposite sides along the Z direction, and the first direction is parallel to the Y direction.

18. The battery pack according to claim 17, characterized in that the single cell is substantially a rectangular parallelepiped and has a length L, a width H, and a thickness D, wherein the length L of the single cell is greater than or equal to the width H, and the width H of the single cell is greater than the thickness D, where the X direction is the thickness direction of the single cell, the Y direction is either the length direction or the width direction of the single cell, and the Z direction is the other of the length direction or the width direction of the single cell.

19. The battery pack according to claim 17 or 18, wherein each single cell includes six surfaces: a bottom surface, a top surface, two first sides, and two second sides, the two first sides being located on opposite sides along the thickness direction, the two second sides being located on opposite sides along the length direction, and the bottom surface and top surface being located on opposite sides along the width direction.

20. The battery pack according to any one of claims 17 to 19, wherein the case includes a first frame and a second frame installed opposite to each other along the Y direction, the battery module is installed between the first frame and the second frame, one end of the battery module is supported by the first frame, and the other end of the battery module is supported by the second frame.

21. The battery pack according to any one of claims 1 to 20, characterized in that the reinforcing member is fixed and attached to the first side surface of each of the Q adjacent single cells using a structural adhesive.

22. The battery pack according to claim 21, characterized in that the structural adhesive is a structural adhesive having thermal conductivity.

23. The battery pack according to any one of claims 1 to 22, characterized in that the reinforcing member is a reinforcing plate.

24. The battery pack according to claim 23, characterized in that the reinforcing plate is a steel plate, an aluminum plate, or a glass fiber plate.

25. The battery pack according to any one of claims 1 to 24, characterized in that a plurality of battery modules are installed and there is a gap between two adjacent battery modules.

26. The battery pack according to any one of claims 1 to 25, characterized in that the second sides of two adjacent single cells in the battery unit are bonded together.

27. The battery pack according to any one of claims 1 to 26, wherein a plurality of battery modules are installed, and a reinforcing member is installed between at least two adjacent battery modules.

28. The battery pack according to claim 27, characterized in that the reinforcing member is fixedly attached to the battery modules located on both sides of the reinforcing member.

29. The battery pack according to claim 28, characterized in that the reinforcing member is an aluminum plate or a steel plate.

30. The battery pack according to any one of claims 1 to 29, wherein the case includes a tray and an upper cover that both define a storage space, the battery module is located within the storage space, and the single cells in the battery module have their top surfaces fixedly attached to the inner surface of the upper cover and their bottom surfaces fixedly attached to the inner surface of the tray.

31. The battery pack according to claim 30, characterized in that the tray and / or the upper cover have a multilayer composite structure.

32. The battery pack according to claim 31, characterized in that the multilayer composite structure includes two layers of aluminum plates and a steel plate or foamed aluminum plate sandwiched between the two layers of aluminum plates.

33. The battery pack according to claim 31 or 32, characterized in that the multilayer composite structure includes two fiber composite layers and a foam material layer sandwiched between the two fiber composite layers.

34. The battery pack according to claim 33, characterized in that the fiber composite layer includes a glass fiber layer and / or a carbon fiber layer.

35. The battery pack according to any one of claims 1 to 34, characterized in that a plurality of battery modules are installed, the second sides of two adjacent single cells in one battery module are bonded together and the bonded position is denoted as the first position, the second sides of two adjacent single cells in another adjacent battery module are bonded together and the bonded position is denoted as the second position, and the first position and the second position are installed spaced apart along the first direction.

36. The battery pack according to any one of claims 1 to 35, characterized in that multiple battery modules are installed, two adjacent single cells in one battery module are installed separated by a first section, two adjacent single cells in another adjacent battery module are installed separated by a second section, and the projection of the first section in a first direction and the projection of the second section in a first direction do not overlap.

37. The battery pack according to 35 or 36, characterized in that the number of individual cells in two adjacent battery modules are different, one battery module is denoted as the first battery module and the other battery module is denoted as the second battery module, the number of individual cells in the first battery module is greater than the number of individual cells in the second battery module, and reinforcing blocks connected to the individual cells in the second battery module are installed in the second battery module.

38. An electric vehicle characterized by including a battery pack according to any one of claims 1 to 37.

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