Battery pack

Abstract

According to an exemplary embodiment, a battery pack is provided. The battery pack includes a lower frame including a base plate and side walls; first to fourth battery cell assemblies disposed on the lower frame and including a plurality of battery cells; a first cross beam interposed between the first battery cell assembly and the second battery cell assembly, the first and second battery cell assemblies being separated in a first direction; a second cross beam interposed between the third and fourth battery cell assembly, the third and fourth battery cell assemblies being separated in a second direction perpendicular to the first direction from the first and second battery cell assemblies, a first stabilization coupled to the first cross beam and separated from the base plate; and a second stabilization coupled to the first stabilization.

Description

Technical Field

[0004] , , , , , , ,

[0005] ,

[0001] The present invention relates to a housing and a battery pack including the same. This application claims the benefit of Korean Application No. 10-2023-0160157, filed on November 20, 2023, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as handsets, notebook computers, and cordless vacuum cleaners. In recent years, due to improvements in energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased dramatically, and as the driving range of battery electric vehicles (BEVs) has increased to a level comparable to that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to mobility. <00,00011> The trend in the technological development of secondary batteries for mobility is to improve energy density and safety. The safety of secondary batteries for mobility is extremely important as it directly relates to the lives of passengers. The safety of secondary batteries can be achieved through mechanical robustness, reliability of electrical insulation, and heat transfer delay during the occurrence of thermal runaway events.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the technical idea of the present invention is to provide a battery pack with improved safety and energy density.

Means for Solving the Problems

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, a battery pack is provided. The battery pack includes a lower frame including a base plate and side walls; first to fourth battery cell assemblies disposed on the lower frame and including a plurality of battery cells; a first cross beam interposed between the first battery cell assembly and the second battery cell assembly, the first and second battery cell assemblies being separated in a first direction; a second cross beam interposed between the third battery cell assembly and the fourth battery cell assembly, the third and fourth battery cell assemblies being separated in a second direction perpendicular to the first direction from the first battery cell assembly and the second battery cell assembly; a first stabilizer coupled to the first cross beam and separated from the base plate; and a second stabilizer coupled to the first stabilizer.

[0006] The above battery pack further includes a lid attached to the side wall.

[0007] The battery pack further includes a gasket interposed between the second fixture and the lid.

[0008] Each of the second fixtures described above includes a flange, the flange includes a groove having a depth less than the height of each of the gaskets, and the gaskets are placed in the grooves.

[0009] The above battery pack further includes a center bracket positioned on the above lid.

[0010] The battery pack is characterized in that the center bracket is coupled to the second fixing device.

[0011] The battery pack further includes a third fixing device that is coupled to the second fixing device and in contact with the center bracket.

[0012] The first end of the center bracket is fixed to the first crossbeam, and the second end of the center bracket is fixed to the second crossbeam.

[0013] The above lid is secured by the above center bracket.

[0014] The battery pack further includes a center beam interposed between the first battery cell assembly and the second battery cell assembly.

[0015] The above-mentioned center beam overlaps with the above-mentioned center bracket.

[0016] The above-mentioned center beam is perpendicular to the above-mentioned center bracket.

[0017] Each of the above-mentioned second fixtures includes a first cylindrical portion, a flange portion having a larger diameter than the first cylindrical portion, a hexagonal portion separated from the first cylindrical portion with the flange portion in between, and a second cylindrical portion separated from the flange portion with the hexagonal portion in between.

[0018] Each of the above-mentioned second fixtures further includes the adhesive applied to the above-mentioned first cylindrical portion.

[0019] Each of the first cylindrical portions of the second fixture is coupled to the corresponding portion of the first fixture. [Effects of the Invention]

[0020] According to an exemplary embodiment of the present invention, the internal space of the battery pack occupied by the fasteners for securing the center bracket can be minimized. This allows for the provision of a battery pack with improved energy density.

[0021] The effects obtainable from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those with ordinary knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects associated with implementing the exemplary embodiments of the present disclosure can also be derived by those with ordinary knowledge in the technical field from the exemplary embodiments of the present disclosure.

Brief Description of the Drawings

[0022] [Figure 1] It is a flowchart showing a method for manufacturing a battery pack according to an exemplary embodiment. [Figure 2] It is a perspective view for explaining a method for manufacturing a battery pack according to an exemplary embodiment. [Figure 3] It is a partial perspective view enlarging a part of FIG. 2. [Figure 4] It is a cross-sectional view taken along the cutting line 3I-3I' of FIG. 3. [Figure 5] It is a cross-sectional view taken along the cutting line 3II-3II' of FIG. 3. [Figure 6] It is a perspective view for explaining a method for manufacturing a battery pack according to an exemplary embodiment. [Figure 7] It is a partial perspective view enlarging a part of FIG. 6. [Figure 8] It is a cross-sectional view taken along the cutting line 7I-7I' of FIG. 7. [Figure 9] The second fixing device is shown. [Figure 10] It is a perspective view for explaining a method for manufacturing a battery pack according to an exemplary embodiment. [Figure 11] It is a partial perspective view enlarging a part of FIG. 10. [Figure 12] It is a cross-sectional view taken along the cutting line 11I-11I' of FIG. 11. [Figure 13] It is a perspective view for explaining a method for manufacturing a battery pack according to an exemplary embodiment. [Figure 14] It is a partial perspective view enlarging a part of FIG. 13. [Figure 15] This is a cross-sectional view along the cutting line 14I-14I' in Figure 14. [Modes for carrying out the invention]

[0023] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Before that, however, terms and words used herein and in the claims shall not be interpreted to be limited to their usual or dictionary meanings, but rather to be interpreted as meanings and concepts consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their own invention.

[0024] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention; there may be a variety of equivalents and modifications that can substitute for them at the time of filing.

[0025] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, such detailed description will be omitted.

[0026] Since embodiments of the present invention are provided to give a more complete explanation to an ordinary person of the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes and proportions.

[0027] (First and second embodiments) Figure 1 is a flowchart showing a method for manufacturing a battery pack according to an exemplary embodiment.

[0028] Figure 2 is a perspective view illustrating a method for manufacturing a battery pack according to an exemplary embodiment.

[0029] Figure 3 is a magnified partial perspective view of part POR2 in Figure 2.

[0030] Figure 4 is a cross-sectional view along the cutting line 3I-3I' in Figure 3.

[0031] Figure 5 is a cross-sectional view along the cutting line 3II-3II' in Figure 3.

[0032] Figure 6 is a perspective view illustrating a manufacturing method for a battery pack according to an exemplary embodiment.

[0033] Figure 7 is a magnified partial perspective view of part POR6 in Figure 6.

[0034] Figure 8 is a cross-sectional view along the cutting line 7I-7I' in Figure 7.

[0035] Figure 9 shows the second stabilization device.

[0036] Figure 10 is a perspective view illustrating a method for manufacturing a battery pack according to an exemplary embodiment.

[0037] Figure 11 is a magnified partial perspective view of part POR10 of Figure 10.

[0038] Figure 12 is a cross-sectional view along the cutting line 11I-11I' in Figure 11.

[0039] Figure 13 is a perspective view illustrating a manufacturing method for a battery pack according to an exemplary embodiment.

[0040] Figure 14 is a magnified partial perspective view of part POR13 in Figure 13.

[0041] Figure 15 is a cross-sectional view along the cutting line 14I-14I' in Figure 14.

[0042] Referring to Figures 1 to 5, the battery cell assembly can be placed in the lower frame at P110.

[0043] The lower frame 110 can provide space for mounting the battery cell assembly 120, which will be described later. The lower frame 110 may include a base plate 111 and first to fourth side walls 112, 113, 114, and 115. Multiple crossbeams 130 can be provided on the lower frame 110.

[0044] The two directions substantially parallel to the upper surface 111U of the base plate 111 are defined as the X and Y directions, and the direction substantially perpendicular to the upper surface 111U of the base plate 111 is defined as the Z direction. The X, Y, and Z directions may each be substantially perpendicular to one another. Unless otherwise stated, the definitions of directions are the same for the following drawings.

[0045] The base plate 111 may include multiple plates. These multiple plates may be joined together, for example, by friction stir welding. Each of the multiple plates may include cooling channels, cavities, and ribs. Each of the cooling channels, cavities, and ribs may extend in the X direction.

[0046] Cooling channels can provide a path for the cooling fluid to flow. Cooling channels can be spaced apart in the Y direction. Cooling channels can be arranged along the Y direction. Cavities are empty spaces formed inside multiple plates. The formation of cavities can reduce the mass of the multiple plates, thereby improving the energy density of the battery pack 100 (see Figure 13), including the lower frame 110. Ribs can define the cooling channels and cavities. Ribs can surround the cooling channels and cavities. Ribs can maintain airtightness of the cooling channels and cavities.

[0047] Among the multiple plates, the one positioned in the center may include a center beam CB. The center beam 111CB may protrude from the upper surface of the base plate 111. The center beam 111CB may be extended in the X direction.

[0048] The first side wall 112 and the second side wall 113 can be coupled to the base plate 111. The first side wall 112 and the second side wall 113 can be separated in the Y direction with the base plate 111 in between. Each of the first side wall 112 and the second side wall 113 may include a plate portion co-plane with the base plate 111, a wall portion perpendicular to the plate portion, and a wing portion outside the wall portion. Each wall portion of the first side wall 112 and the second side wall 113 may be substantially perpendicular to the Y direction. Each wing portion of the first side wall 112 and the second side wall 113 may include a plurality of coupling holes. Each wing portion of the first side wall 112 and the second side wall 113 can be used for transporting and / or securing the lower frame 110 (e.g., securing the lower frame 110 to a vehicle or other battery tray).

[0049] The third side wall 114 and the fourth side wall 115 can be coupled to the base plate 111. The third side wall 114 and the fourth side wall 115 can be positioned on the base plate 111. The third side wall 114 and the fourth side wall 115 can be spaced apart in the X direction. The third side wall 114 and the fourth side wall 115 may be substantially perpendicular to the X direction. The third side wall 114 may include multiple exhaust holes for installing exhaust equipment.

[0050] Multiple battery cell assemblies 120 can be placed on a base plate 111 of a lower frame 110. The base plate 111 can support the multiple battery cell assemblies 120. The first to fourth side walls 112, 113, 114, and 115 can horizontally enclose the multiple battery cell assemblies 120. The first to fourth side walls 112, 113, 114, and 115 can protect the multiple battery cell assemblies 120.

[0051] According to an exemplary embodiment, the battery pack 100 (see Figure 13) is of a moduleless type, and each of the multiple battery cell assemblies 120 does not necessarily have to include a module frame. Each of the multiple battery cell assemblies 120 may include a cell stack 121 and a top cover 127.

[0052] The cell stack 121 may include multiple banks connected in series with each other. Each of the multiple banks may include one or more battery cells connected in parallel. The number of banks connected in series and the number of battery cells connected in parallel can be determined depending on the magnitude of the voltage and current to be output from each of the battery cell assemblies 120.

[0053] A battery cell is the basic unit of a lithium-ion battery, or secondary battery. Each battery cell includes an electrode assembly, electrolyte, and case. Each battery cell can be one of three types: cylindrical, prismatic, or pouch-type. The electrode assembly of a cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of a prismatic battery cell is housed in a prismatic metal can. The electrode assembly of a pouch-type battery cell is housed in a pouch case containing an aluminum laminate sheet.

[0054] An electrode assembly may include a positive electrode, a negative electrode, and a separation membrane interposed between the positive and negative electrodes. The electrode assembly may be either a jelly roll type or a stack type. A jelly roll type electrode assembly may include a winding structure of the positive electrode, negative electrode, and separation membrane interposed between them. A stack type electrode assembly may include multiple sequentially stacked positive electrodes, multiple negative electrodes, and multiple separation membranes interposed between them.

[0055] According to an exemplary embodiment, the cell stack 121 may further include a plurality of separators. The plurality of separators can prevent the plurality of battery cells from swelling by horizontally supporting the plurality of battery cells. According to an exemplary embodiment, the plurality of separators may be thermal barriers. According to an exemplary embodiment, each of the plurality of separators may have a high melting temperature and a low thermal conductivity. According to an exemplary embodiment, each of the plurality of separators may include a flame retardant material such as ceramic and coated glass material. According to an exemplary embodiment, the plurality of separators may be configured to release a fire retarding material and a fire extinguishing agent in the event of a thermal runaway event.

[0056] The top cover 127 can be placed on the cell stack 121. The top cover 127 may include, for example, an insulating material. The top cover 127 can cover the cell stack 121.

[0057] The crossbeam 130 can isolate multiple battery cell assemblies 120 from each other. The crossbeam 130 can be interposed between multiple battery cell assemblies 120. Multiple battery cell assemblies 120 can be separated in the X direction with the crossbeam 130 in between. The crossbeam 130 can be extended in the Y direction.

[0058] Each of the crossbeams 130 may contain multiple openings 130OP. A first fixture 131 can be coupled to the multiple openings 130OP. Each of the first fixtures 131 may include a flange 131F and a deformed flange 131DF. Each of the first fixtures 131 may be a blind nut. Each of the first fixtures 131 can be coupled to a corresponding crossbeam 130. Each of the first fixtures 131 can be partially embedded in a corresponding crossbeam 130. The deformed flange 131DF can be formed in the process of coupling each of the first fixtures 131 to a rib of a corresponding crossbeam 130. Multiple battery cell assemblies 120 can be arranged in the X and Y directions. In Figure 1, there are three multiple battery cell assemblies 120 arranged in the X direction and two multiple battery cell assemblies 120 arranged in the Y direction. Thus, such an arrangement of multiple battery cell assemblies 120 can be described as a 3×2 arrangement. A typical engineer in this industry can easily arrive at a plurality of battery cell assemblies 120 arranged in M ​​× N (where M and N are integers greater than or equal to 2) based on what is described here.

[0059] The center beam 111CB can isolate multiple battery cell assemblies 120 in the Y direction. The center beam 111CB can be interposed between multiple battery cell assemblies 120. The center beam 111CB can be interposed between cross beams 130. A portion of the cross beam 130 can be separated in the Y direction from another portion of the cross beam 130 with the center beam 111CB in between.

[0060] Next, referring to Figures 1 and 6-9, at P120, the second fixture 133 can be connected to the first fixture 131.

[0061] The second fixing device 133 may be, for example, a bidirectional bolt. Each of the second fixing devices 133 may include a first cylindrical portion (Shank) 133S1, a flange 133F, a hexagonal portion 133H, and a second cylindrical portion 133S2.

[0062] The first cylindrical portion 133S1 may have a substantially cylindrical shape. Each of the second fixtures 133 may further include the adhesive 133A applied to the first cylindrical portion 133S1.

[0063] The flange 133F may have a substantially disc shape. The diameter of the flange 133F may be larger than the diameter of the first cylindrical portion 133S1. The flange 133F may be connected to the first cylindrical portion 133S1. The flange 133F may include grooves 133G. A corresponding gasket 135 may be placed in the groove 133G of each flange 133F of the second fixture 133. The height of each gasket 135 may be greater than the depth of the groove 133G.

[0064] The hexagonal portion 133H may have a substantially hexagonal prism shape. The hexagonal portion 133H may be connected to the flange 133F. The hexagonal portion 133H may be separated from the first cylindrical portion 133S1 with the flange 133F in between.

[0065] The second cylindrical portion 133S2 may have a substantially cylindrical shape. The diameter of the second cylindrical portion 133S2 may be smaller than the diameter of the flange 133F. The second cylindrical portion 133S2 may be connected to the hexagonal portion 133H. The second cylindrical portion 133S2 may be separated from the flange 133F with the hexagonal portion 133H in between.

[0066] Next, referring to Figures 1 and 10-12, a lid 140 can be provided at P130. The lid 140 can be coupled to the lower frame 110. The lid 140 can be coupled to the first to fourth side walls 112, 113, 114, and 115 of the lower frame 110. A gasket 135 can be interposed between the flange 133F of the corresponding second fixture 133 and the lid 140. This allows the gasket 135 to be pressurized by the lid 140, thereby providing a liquid-tight seal in the internal space defined by the lid 140 and the lower frame 110.

[0067] Next, referring to Figures 1 and 13-15, a center bracket 150 can be provided at P140. The center bracket 150 can be fixed by a second fixture 133 and a third fixture 137. The center bracket 150 can be in contact with the corresponding second fixture 133 and third fixture 137. The center bracket 150 may include a portion interposed between the second fixture 133 and the third fixture 137.

[0068] The battery pack 100 can be provided by providing and connecting a center bracket 150. The battery pack 100 may include a lower frame 110, multiple battery cell assemblies 120, first to third fixtures 131, 133, 137, a gasket 135, a lid 140, and a center bracket 150.

[0069] The center bracket 150 can be positioned on the lid 140. The center bracket 150 can be in contact with the lid 140. The center bracket 150 can fix the lid 140 in place. The center bracket 150 can press down on the lid 140. The center bracket 150 can be extended in the Y direction. The center bracket 150 can overlap with the center beam 111CB. The center bracket 150 can be coupled to the second fixture 133.

[0070] The first end of the center bracket 150 can be fixed to the first crossbeam by first to third fixtures 131, 133, and 137, and the second end of the center bracket 150 can be fixed to the second crossbeam by first to third fixtures 131, 133, and 137. The first and second crossbeams may be included in the crossbeam 130. The first and second crossbeams may be spaced apart with the center beam 111CB in between and overlap each other in the Y direction. The first crossbeam may be interposed between the center beam 111CB and the first side wall 112, and the second crossbeam may be interposed between the center beam 111CB and the second side wall 113.

[0071] Battery cell assemblies 120 adjacent to the first crossbeam (i.e., spaced apart from each other with the first crossbeam in between) are referred to as the first and second battery cell assemblies, and battery cell assemblies 120 adjacent to the second crossbeam (i.e., spaced apart from each other with the second crossbeam in between) are referred to as the third and fourth battery cell assemblies.

[0072] According to an exemplary embodiment, the center bracket 150 can be secured by a first fixture 131 coupled to the crossbeam 130, a second fixture 133 coupled to the first fixture 131, and a third fixture 137 coupled to the second fixture 133. This prevents (or mitigates or minimizes) the fixtures for securing the center bracket 150 from occupying internal space in the battery pack 100, thereby improving the energy density (e.g., volume density) of the battery pack 100.

[0073] The battery pack 100 may further include a plurality of exhaust devices. The plurality of exhaust devices may be coupled, for example, to a third side wall 115. The plurality of exhaust devices may be coupled, for example, to exhaust holes in the third side wall 115. Each of the plurality of exhaust devices may include a spring type or a rupture disc. Each of the plurality of exhaust devices may be configured to expel gas from inside the battery pack 100 when the pressure inside the battery pack 100 exceeds a threshold.

[0074] Multiple exhaust devices can be configured to slow down thermal propagation by releasing hot gases from inside the battery pack 100 to the outside when at least one of the multiple battery cell assemblies 120 is in a thermal runway state.

[0075] Here, thermal runaway of the multiple battery cell assemblies 120 is a state in which the temperature change of the multiple battery cell assemblies 120 is further accelerated, resulting in an uncontrollable positive feedback loop. In a thermal runaway state, the multiple battery cell assemblies 120 exhibit a rapid temperature increase and emit large amounts of high-pressure gas and combustion residue.

[0076] The battery pack 100 may further include electrical components. These electrical components may be mounted on the lower frame 110. The electrical components may be positioned between the third side wall 113, where the exhaust system is installed, and the multiple battery cell assemblies 120. The electrical components may include any electronic elements necessary to power the battery pack.

[0077] Electrical components may include, for example, a Battery Management System (BMS). The BMS can be configured to perform tasks such as monitoring, balancing, and controlling the battery pack. Monitoring of the battery pack 100 may include measuring the voltage and current at specific nodes within a plurality of battery cell assemblies 120, and measuring the temperature at a set location within the battery pack 100. The battery pack 100 may include measuring instruments for measuring the aforementioned voltage, current, and temperature.

[0078] Balancing the battery pack 100 is an operation that reduces deviations between multiple battery cell assemblies 120. Control of the battery pack 100 includes preventing overcharging, over-discharging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing shortening of the lifespan of each of the multiple battery cell assemblies 120.

[0079] The electrical components may further include a cooling system, a Power Relay Assembly (PRA), a safety plug, and the like. The cooling system may include a cooling fan. The cooling fan can prevent each of the multiple battery cell assemblies 120 from overheating by circulating air inside the battery pack 100. The PRA can be configured to supply or cut off power from the high-voltage battery to an external load (e.g., the vehicle's motor). The PRA can protect the multiple battery cell assemblies 120 and the external load (e.g., the vehicle's motor) by cutting off the power supply to the external load (e.g., the vehicle's motor) in situations where abnormal voltages occur, such as voltage surges.

[0080] The battery pack 100 may further include a plurality of busbars configured to electrically connect a plurality of battery cell assemblies 120. The plurality of battery cell assemblies 120 may be connected in series by the plurality of busbars. This allows the battery pack 100 to be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0081] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be a variety of equivalents and modifications that can be substituted for them at the time of filing. [Explanation of symbols]

[0082] 100 Battery Packs 110 Lower frame 111 Base Plate 111CB Center Beam 111U top 112 First side wall 113 Second side wall 114 Third side wall 115 Fourth side wall 120 Battery Cell Assembly 121 Cell Stack 127 Top Cover 130 Crossbeam 130OP opening 131 1st fixator 131DF Flange 131F Flange 133 Second fixator 133A Adhesive 133F Flange 133G Groove 133H Hexagonal part 133S1 First cylindrical section 133S2 Second cylindrical section 135 Gasket 137 Third fixator 140 Lid 150 Center Bracket

Claims

1. A lower frame including a base plate and side walls, Displaced on the lower frame, a first to fourth battery cell assembly including a plurality of battery cells, A first cross beam interposed between the first battery cell assembly and the second battery cell assembly, wherein the first battery cell assembly and the second battery cell assembly are separated in a first direction. A second crossbeam interposed between the third battery cell assembly and the fourth battery cell assembly, wherein the third battery cell assembly and the fourth battery cell assembly are separated from the first battery cell assembly and the second battery cell assembly in a second direction perpendicular to the first direction, A first fixing device coupled to the first cross beam and separated from the base plate, A battery pack including a second stabilizer coupled to the first stabilizer.

2. The battery pack according to claim 1, further comprising a lid coupled to the side wall.

3. The battery pack according to claim 2, further comprising a gasket interposed between the second fixing device and the lid.

4. Each of the XL2 fixtures includes a flange, The flange includes grooves having a depth less than the height of each of the gaskets, The battery pack according to claim 3, wherein the gasket is disposed in the groove.

5. The battery pack according to any one of claims 2 to 4, further comprising a center bracket positioned on the lid.

6. The battery pack according to claim 5, wherein the center bracket is coupled to the second fixing device.

7. The battery pack according to claim 5, further comprising a third fixing device coupled to the second fixing device and in contact with the center bracket.

8. The first end of the center bracket is fixed to the first crossbeam. The battery pack according to claim 5, wherein the second end of the center bracket is fixed to the second crossbeam.

9. The battery pack according to claim 5, wherein the lid is secured by the center bracket.

10. The system further includes a center beam interposed between the first battery cell assembly and the second battery cell assembly, The battery pack according to claim 5, wherein the center beam overlaps with the center bracket.

11. The battery pack according to claim 10, wherein the center beam is perpendicular to the center bracket.

12. Each of the second fixtures is, The first cylindrical section and A flange portion having a larger diameter than the first cylindrical portion, A hexagonal portion separated from the first cylindrical portion with the flange portion in between, A battery pack according to any one of claims 1 to 4, comprising a second cylindrical portion separated from the flange portion with the hexagonal portion in between.

13. The battery pack according to claim 12, wherein each of the second fixing devices further comprises the adhesive applied to the first cylindrical portion.

14. The battery pack according to claim 12, wherein each of the first cylindrical portions of the second fixing device is coupled with a corresponding portion of the first fixing device.

Images