Battery pack and device containing same

Abstract

A battery pack according to one embodiment of the present invention includes a battery module including a first sub-battery module and a pair of second sub-battery modules located on either side of the first sub-battery module; a pack frame to which the battery module is mounted; and a pair of connecting parts penetrating upper and lower parts of the first sub-battery module and the pair of second sub-battery modules, respectively, both sides of the pair of connecting parts are fixed to side parts of the pack frame, the first sub-battery module is fixed to a bottom surface of the pack frame, and the second sub-battery module moves along the longitudinal direction of the connecting parts.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0107955 dated August 17, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery pack and a device including the same, and more particularly to a battery pack and a device including the same that prevent excessive warping of a frame member and deterioration of the lifespan of a battery cell when swelling of the battery cell occurs. [Background technology]

[0003] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles or hybrid vehicles powered by electrical sources, power storage devices, etc. These secondary batteries are attracting attention as a new energy source for improving energy efficiency, not only because they have the primary advantage of dramatically reducing the use of fossil fuels, but also because they are environmentally friendly in that they do not produce any by-products associated with energy use.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, a very low self-discharge rate, and high energy density.

[0005] Generally, lithium secondary batteries can be classified according to the shape of the exterior material into cylindrical or prismatic secondary batteries in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries in which the electrode assembly is housed in an aluminum laminate sheet pouch.

[0006] Recently, as the use of secondary batteries as energy storage sources and the need for large-capacity secondary battery structures have increased, there has been an increasing demand for battery packs with medium to large modular structures that assemble battery modules in which multiple secondary batteries are connected in series or parallel. Such battery modules improve capacity and output by connecting multiple battery cells in series or parallel to form a battery cell stack. In addition, multiple battery modules can be installed together with various control and protection systems such as a Battery Management System (BMS) and a cooling system to form a battery pack.

[0007] Figure 1 is a top view of a conventional battery pack, and Figure 2 is a top view of the battery pack of Figure 1 at the end of battery life (EOL).

[0008] Referring to FIG. 1, a conventional battery pack 10 includes a structure in which battery modules 11 are mounted between pack frames 15. However, battery cells (11a, FIG. 3) included in the battery module 11 typically undergo repeated expansion and contraction during charging and discharging. For example, as shown in FIG. 2, a battery module 11 at the end of its life has a swelling portion 11s that expands toward the pack frame 15. This swelling portion 11s weakens the rigidity of the battery module 11, and the deviation in pressure applied to the battery cells (11a, FIG. 3) included in the battery module 11 can also lead to problems with shortened lifespan.

[0009] FIG. 3 is a cross-sectional view of the battery module taken along the aa' axis in FIG.

[0010] 3, in a conventional battery module 11, battery cells 11a are adhered or pressurized to a module frame 11b. A compression pad 11p may be located on one side of the battery cell stack in which the battery cells 11a are stacked.

[0011] In particular, with the recent trend of gradually increasing the capacity of the battery cells 11a, the amount of swelling of the battery cells 11a also increases significantly, and the amount of displacement that the module frame 11b must absorb also increases.

[0012] However, even in the case of the compression pad 11p, it is difficult to sufficiently absorb the deformation applied to the module frame 11b during the expansion and contraction process associated with charging and discharging of the battery cell 11a, which can lead to the problem of the module frame 11b being easily deformed to form a swelling portion 11s as shown in Figure 2.

[0013] Therefore, in addition to the conventional battery pack 10 and battery module 11, it is necessary to develop a battery pack and battery module with a new structure that prevents the formation of swelling portions 11s during the expansion and contraction process associated with charging and discharging of the battery cells, thereby minimizing deformation of the module frame 11b, while also preventing deterioration in the lifespan of the battery cells 11a. Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a battery pack and a device including the same that prevent excessive warping of a frame member and deterioration of the lifespan of a battery cell when swelling of the battery cell occurs.

[0015] The problems to be solved by the present invention are not limited to the problems described above, and problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0016] A battery pack according to one embodiment of the present invention includes a battery module including a first sub-battery module and a pair of second sub-battery modules located on either side of the first sub-battery module; a pack frame to which the battery module is attached; and a pair of connecting parts passing through upper and lower parts of the first sub-battery module and the pair of second sub-battery modules, respectively, wherein both sides of the pair of connecting parts are fixed to side parts of the pack frame, the first sub-battery module is fixed to a bottom surface of the pack frame, and the second sub-battery module moves along the longitudinal direction of the connecting parts.

[0017] The battery pack may further include frame members attached to upper and lower portions of the first sub-battery module and the pair of second sub-battery modules, the frame members surrounding at least a portion of the outer surfaces of the pair of second sub-battery modules.

[0018] Both side portions of the frame member may move along the longitudinal direction of the connecting portion together with the second sub-battery module, and the center portion of the frame member may extend along the longitudinal direction of the connecting portion together with the second sub-battery module.

[0019] The frame member may be made of one or more materials selected from the group consisting of glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP).

[0020] The frame member may include a first frame member and a second frame member, the first frame member being attached to the upper part of the first sub-battery module and the pair of second sub-battery modules, and the second frame member being attached to the lower part of the first sub-battery module and the pair of second sub-battery modules.

[0021] Both ends of the first frame member may extend along the outer surfaces of the pair of second sub-battery modules, and both ends of the second frame member may extend along the outer surfaces of the pair of second sub-battery modules, and the ends of the first frame member and the ends of the second frame member may be spaced apart from each other.

[0022] The pack frame may further include an end plate positioned between the frame member and a side portion of the pack frame.

[0023] The end plates may contact outer surfaces of the frame members located on outer sides of the pair of second sub-battery modules.

[0024] The pair of connecting portions may pass through the upper and lower portions of the end plate, respectively.

[0025] Both sides of the pair of connecting portions are bolted to the side surfaces of the pack frame. Conclusion The first sub-battery module is bolted to the bottom surface of the pack frame. Conclusion They may also be combined.

[0026] The first sub-battery module may include a first battery cell stack in which a plurality of first battery cells are stacked, and the second sub-battery module may include a second battery cell stack in which a plurality of second battery cells are stacked.

[0027] The first sub-battery module may include a pair of first module frames respectively attached to the upper and lower portions of the first battery cell stack, and the second sub-battery module may include a pair of second module frames respectively attached to the upper and lower portions of the second battery cell stack.

[0028] The pair of connecting portions may pass through the pair of first module frames, respectively, and may pass through the pair of second module frames, respectively.

[0029] Both side surfaces of the first battery cell stack and both side surfaces of the second battery cell stack may be exposed to the outside.

[0030] A first fixing member may be formed between the first module frame and the first battery cell stack, and a second fixing member may be formed between the second module frame and the second battery cell stack.

[0031] A device according to another embodiment of the present invention includes the battery pack described above. [Effects of the Invention]

[0032] According to an embodiment, the present invention provides a battery pack and a device including the same in which a first sub-battery module is fixed to the bottom surface of a pack frame and a second sub-battery module moves along the longitudinal direction of a connecting portion, and which can prevent excessive warping of frame members and deterioration of the lifespan of battery cells when swelling occurs in battery cells.

[0033] The effects of the present invention are not limited to the effects described above, and any unmentioned effects will be clearly understood by those skilled in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 10 is a top view of a conventional battery pack. [Figure 2] FIG. 2 is a top view of the battery pack of FIG. 1 at the end-of-life (EOL) stage. [Figure 3] FIG. 2 is a cross-sectional view of the battery module taken along the a-a' axis in FIG. [Figure 4] 1 is a top view schematically illustrating a battery pack according to an embodiment of the present invention; [Figure 5] FIG. 5 is a cross-sectional view of the battery pack of FIG. 4 as seen from the front. [Figure 6]6 is a cross-sectional view showing a structure in which a first sub-battery module and a connecting portion in the battery pack of FIG. 5 are coupled together. FIG. [Figure 7] 7 is a cross-sectional view showing a structure in which a second sub-battery module is coupled to a connecting portion in the cross-section of FIG. 6; FIG. [Figure 8] 7 is a cross-sectional view showing a structure in which a second sub-battery module is coupled to a connecting portion in the cross-section of FIG. 6; FIG. [Figure 9] 8 is a cross-sectional view showing a structure in which frame members are coupled to the upper and lower parts of a first sub-battery module and a pair of second sub-battery modules in the cross section of FIG. 7. FIG. [Figure 10] 8 is a cross-sectional view showing a structure in which frame members are coupled to the upper and lower parts of a first sub-battery module and a pair of second sub-battery modules in the cross section of FIG. 7. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0036] In order to clearly explain the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0037] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0038] Also, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, rather than excluding other elements, unless otherwise specified to the contrary.

[0039] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0040] Hereinafter, a battery pack according to an embodiment of the present invention will be described. However, the description will be based on one cross section of the battery pack, and the same or similar content may be described for other cross sections of the battery pack.

[0041] Fig. 4 is a top view schematically showing a battery pack according to one embodiment of the present invention, and Fig. 5 is a cross-sectional view of the battery pack shown in Fig. 4 as seen from the front.

[0042] 4 and 5, the battery pack 1000 according to this embodiment includes a battery module 100 including a first sub-battery module 110 and a pair of second sub-battery modules 120 located on either side of the first sub-battery module 110; a pack frame 1500 to which the battery module 100 is attached; and a pair of connecting portions 1300 penetrating the top and bottom of the first sub-battery module 110 and the pair of second sub-battery modules 120, respectively.

[0043] More specifically, the pair of connecting portions 1300 includes a first connecting portion and a second connecting portion, where the first connecting portion penetrates the upper portions of the first sub-battery module 110 and the pair of second sub-battery modules 120, respectively, and the second connecting portion penetrates the lower portions of the first sub-battery module 110 and the pair of second sub-battery modules 120, respectively.

[0044] In addition, the pair of connecting parts 1300 may penetrate the upper and lower parts of the front and / or rear surface of the battery module 100, respectively. For example, as shown in Fig. 4, the pair of connecting parts 1300 may penetrate the upper and lower parts of the front surface of the battery module 100, respectively, and may penetrate the upper and lower parts of the rear surface of the battery module 100, respectively. As another example, the pair of connecting parts 1300 may penetrate the upper and lower parts of the battery module 100, respectively, based on the center of the battery module 100. As another example, the pair of connecting parts 1300 may penetrate the upper and lower parts of the front, rear, and center of the battery module 100, respectively.

[0045] For example, the pair of connecting parts 1300 may be rod-shaped members made of steel. However, the material and shape of the pair of connecting parts 1300 are not limited thereto, and any member having a material and shape that is rigid enough to sufficiently support the upper and lower parts of the battery module 100 while penetrating the upper and lower parts of the battery module 100 may be included in this embodiment.

[0046] The pack frame 1500 also includes side portions 1510 and a bottom surface 1550. Here, the battery module 100 is positioned on the bottom surface 1550, and the battery module 100 is attached between the pair of side portions 1510. More specifically, the side portions 1510 may be integrated with the bottom surface 1550 or may be fixed to the bottom surface 1550 by a joining method such as welding.

[0047] Here, both sides of the pair of connecting portions 1300 are fixed to side portions 1510 of the pack frame 1500. More specifically, both sides of the first connecting portion may be fixed to the upper side of the pack frame 1500, and both sides of the second connecting portion may be fixed to the lower side of the pack frame 1500.

[0048] As an example, both sides of the pair of connecting portions 1300 are bolted to the side portions 1510 of the pack frame 1500. ConclusionHowever, the coupling method of the pair of connecting parts 1300 is not limited to this, and any method that can stably fix the two sides of the pair of connecting parts 1300 to the side parts 1510 of the pack frame 1500 can be included in this embodiment.

[0049] Here, the first sub-battery module 110 of the battery module 100 is fixed to the bottom surface 1550 of the pack frame 1500. In other words, the pair of second sub-battery modules 120 do not have to be fixed to the bottom surface 1550 of the pack frame 1500. That is, the pair of second sub-battery modules 120 can move along the longitudinal direction of the connecting portion 1300. More specifically, the pair of second sub-battery modules 120 can move toward the side surface portion 1510 of the pack frame 1500.

[0050] For example, the first sub-battery module 110 is bolted to the bottom surface 1550 of the pack frame 1500. Conclusion However, the coupling method between the first sub-battery module 110 and the bottom surface 1550 is not limited to this, and any method that can stably fix the first sub-battery module 110 and the bottom surface 1550 may be included in this embodiment.

[0051] With the above configuration, in the battery pack 1000 according to this embodiment, when swelling occurs in some of the battery cells included in the battery module 100, the first sub-battery module 110 is fixed to the bottom surface 1550 of the pack frame 1500, but the pair of second sub-battery modules 120 can move along the longitudinal direction of the connecting portion 1300 due to the connecting portion 1300, thereby alleviating the increase in pressure generated inside the battery module 100.

[0052] That is, even if the volume of a battery cell included in the battery module 100 expands partially when a swelling phenomenon occurs in the battery cell, the pair of second sub-battery modules 120 can move toward the side portion 1510 of the pack frame 1500 via the connecting portion 1300, thereby alleviating the increase in pressure applied between the battery cells due to the swelling phenomenon.

[0053] Fig. 6 is a cross-sectional view showing a structure in which a first sub-battery module and a connecting portion are coupled together in the battery pack of Fig. 5. Figs. 7 and 8 are cross-sectional views showing a structure in which a second sub-battery module is coupled to the connecting portion in the cross section of Fig. 6.

[0054] 5 and 6, the first sub-battery module 110 may include a first battery cell stack 111 in which a plurality of first battery cells are stacked. The first sub-battery module 110 may also include a pair of first module frames 115 attached to upper and lower portions of the first battery cell stack 111, respectively. Here, the pair of first module frames 115 may be integrated with each other or may be separate from each other. Also, as shown in FIG. 6, a pair of connecting portions 1300 may penetrate the upper and lower portions of the first sub-battery module 110, and in particular, may penetrate each of the pair of first module frames 115.

[0055] 5 and 7, the second sub-battery module 120 may include a second battery cell stack 121 in which a plurality of second battery cells are stacked. The second sub-battery module 120 may also include a pair of second module frames 125 attached to the top and bottom of the second battery cell stack 121, respectively. Here, the pair of second module frames 125 may be integrated with each other or may be separate from each other.

[0056] 7, the pair of connecting parts 1300 may penetrate the upper and lower parts of the second sub-battery module 120, and in particular, may penetrate the pair of second module frames 125. The pair of second sub-battery modules 120 may be inserted along the longitudinal direction of the connecting parts 1300 toward both side surfaces of the first sub-battery module 110, respectively.

[0057] Therefore, the battery pack 1000 according to this embodiment can prevent damage to the battery cells included in the battery module 100 and can stably fix the battery module 100 to the connecting part 1300.

[0058] 6 to 8, a first fixing member 117 is formed between the first module frame 115 and the first battery cell stack 111, and a second fixing member 127 is formed between the second module frame 125 and the second battery cell stack 121. More specifically, the first fixing member 117 and the second fixing member 127 may be adhesive members. More preferably, the first fixing member 117 and the second fixing member 127 may be adhesive members having thermal conductivity.

[0059] Therefore, in the battery pack 1000 according to this embodiment, the first battery cell stack 111 and the second battery cell stack 121 can be stably fixed to the first module frame 115 and the second module frame 125, respectively.

[0060] In addition, in the first sub-battery module 110 and the second sub-battery module 120, both side surfaces of the first battery cell stack 111 and both side surfaces of the second battery cell stack 121 are exposed to the outside. In other words, both side surfaces of the first battery cell stack 111 do not have to be covered by the pair of first module frames 115, and both side surfaces of the second battery cell stack 121 do not have to be covered by the pair of second module frames 125. That is, as shown in FIG. 8 , the first sub-battery module 110 and the second sub-battery module 120 may be in contact with each other, and the side surfaces of the first battery cell stack 111 and the second battery cell stack may be in contact with each other.

[0061] Therefore, in the battery pack 1000 according to this embodiment, the side of the first battery cell stack 111 and the side of the second battery cell stack are in contact with each other, thereby increasing space efficiency and battery capacity.

[0062] 5 to 8, the first battery cell or the second battery cell included in the first battery cell stack 111 or the second battery cell stack 121 is preferably a pouch-type battery cell. As an example, the first battery cell or the second battery cell may be manufactured by housing an electrode assembly in a pouch case made of a laminate sheet including a resin layer and a metal layer, and then heat-sealing a sealing portion of the pouch case. The first battery cell or the second battery cell may be formed in a rectangular sheet-like structure. The first battery cell or the second battery cell may be configured in plurality to form the first battery cell stack 111 or the second battery cell stack 121, which are electrically connected to each other.

[0063] Here, the number of the first battery cells and the second battery cells constituting the first battery cell stack 111 or the second battery cell stack 121 may be adjusted depending on the situation. For example, as shown in Figures 5 to 8, the number of the second battery cells included in the second battery cell stack 121 may be greater than the number of the first battery cells included in the first battery cell stack 111.

[0064] 9 and 10 are cross-sectional views showing a structure in which frame members are coupled to the upper and lower parts of the first sub-battery module and a pair of second sub-battery modules in the cross section of FIG.

[0065] 5, 9, and 10, the battery pack 1000 according to the present embodiment may further include a frame member 1700 attached to the upper and lower portions of the first sub-battery module 110 and the pair of second sub-battery modules 120. More specifically, referring to FIG. 9, after compressing both sides of the first sub-battery module 110 and the pair of second sub-battery modules 120, the frame member 1700 is attached to the upper and lower portions of the first sub-battery module 110 and the pair of second sub-battery modules 120 as shown in FIG.

[0066] 5 and 10 , the frame member 1700 may surround at least a portion of the outer surfaces of the pair of second sub-battery modules 120. More specifically, the center of the frame member 1700 extends along the upper and lower portions of the first sub-battery module 110 and the pair of second sub-battery modules 120. In addition, the ends of the frame member 1700 may surround at least a portion of the outer surfaces of the pair of second sub-battery modules 120. Here, the shape of the frame member 1700 may be the same as the shapes of the upper and lower portions of the first sub-battery module 110 and the pair of second sub-battery modules.

[0067] In addition, the frame member 1700 includes a first frame member and a second frame member, the first frame member being attached to the upper part of the first sub-battery module 110 and a pair of second sub-battery modules 120, and the second frame member being attached to the lower part of the first sub-battery module 110 and a pair of second sub-battery modules 120.

[0068] Here, both ends of the first frame member may extend along the outer surfaces of the pair of second sub-battery modules 120, and both ends of the second frame member may extend along the outer surfaces of the pair of second sub-battery modules 120, and the ends of the first frame member and the ends of the second frame member may be spaced apart from each other. However, this is not limited thereto, and a structure in which the ends of the first frame member and the ends of the second frame member are connected to each other may also be included in this embodiment.

[0069] 10 , both sides of the frame member 1700 may move along the longitudinal direction of the connecting portion 1300 together with the second sub-battery module 120, and the center of the frame member 1700 may extend along the longitudinal direction of the connecting portion 1300 together with the second sub-battery module 120. In other words, with both sides of the frame member 1700 fixed to the outer surface of the second sub-battery module 120, as the second sub-battery module 120 moves along the longitudinal direction of the connecting portion 1300, the center of the frame member 1700 may also extend along the longitudinal direction of the connecting portion 1300.

[0070] Here, the frame member 1700 is made of a material with high elasticity and high rigidity. For example, it may be made of one or more materials selected from the group consisting of glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP). As another example, the frame member 1700 may have a spring shape that is easy to stretch. However, the material and shape of the frame member 1700 are not limited thereto, and any material and shape that can be easily stretched by the movement of the second sub-battery module 120 may be included in this embodiment.

[0071] With the above configuration, the battery pack 1000 according to this embodiment has the first sub-battery module 110 and a pair of second sub-battery modules 120 stably fixed within the frame member 1700, and the frame member 1700 can be extended along with the movement of the second sub-battery module 120, thereby preventing excessive deformation of the frame member 1700 while ensuring sufficient rigidity of the battery module 100.

[0072] That is, even if the volume of a battery cell included in the battery module 100 expands partially when swelling occurs in the battery cell, the frame member 1700 extends toward the side portion 1510 of the pack frame 1500 together with the second sub-battery module 120, thereby increasing the amount of displacement and cell reaction force that the frame member 1700 can absorb, and reducing the pressure deviation between the battery cells due to the swelling, thereby preventing deterioration of the battery cell lifespan.

[0073] 5 and 10, the battery pack 1000 according to this embodiment may further include an end plate 1800 located between the frame member 1700 and the side portion 1510 of the pack frame 1500.

[0074] More specifically, the end plate 1800 may contact the outer surface of the frame member 1700 located on the outer surface of the pair of second sub-battery modules 120. That is, when the first sub-battery module 110 and the pair of second sub-battery modules 120 are mounted in the frame member 1700, the end plate 1800 may contact the outer surface of the frame member 1700 located on the outer surface of the pair of second sub-battery modules 120.

[0075] Here, the pair of connecting portions 1300 respectively pass through the upper and lower portions of the end plate 1800. In addition, the end plate 1800 is joined to the outer surface of the frame member 1700 located on the outer surface of the pair of second sub-battery modules 120 by welding or a separate adhesive layer.

[0076] With the above configuration, the battery pack 1000 according to this embodiment has an end plate 1800 joined to the outer surface of the frame member 1700 located on the outer surfaces of the pair of second sub-battery modules 120, and the first sub-battery module 110 and the pair of second sub-battery modules 120 are more stably fixed within the frame member 1700.

[0077] In addition, even when the frame member 1700 is extended with the movement of the second sub-battery module 120, the end plate 1800 can be prevented from separating from the outer surface of the frame member 1700 and the second sub-battery module 120. That is, the amount of displacement and cell reaction force that the frame member 1700 can absorb can be increased, and the pressure deviation applied between the battery cells due to the swelling phenomenon can be reduced, thereby further preventing deterioration in the lifespan of the battery cells.

[0078] The device according to another embodiment of the present invention may be applied to the above-described battery pack. Such devices may be applied to transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and may be applied to various devices that can use battery modules and battery packs including the same, which also fall within the scope of the present invention.

[0079] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0080] 100 Battery Module 110 first sub-battery module 120 Second sub-battery module 1000 battery packs 1300 Connection section 1500 pack frames 1700 Frame members 1800 end plate

Claims

1. a battery module including a first sub-battery module and a pair of second sub-battery modules respectively located on both sides of the first sub-battery module; a pack frame to which the battery module is attached; and a pair of connecting portions respectively penetrating upper and lower portions of the first sub-battery module and the pair of second sub-battery modules; Both sides of the pair of connecting portions are fixed to side portions of the pack frame, the first sub-battery module is fixed to a bottom surface of the pack frame, the second sub-battery module is movable along a longitudinal direction of the connecting portion while being separated from the first sub-battery module; the battery module further includes frame members attached to upper and lower portions of the first sub-battery module and the pair of second sub-battery modules, the frame member surrounds at least a portion of the outer surfaces of the pair of second sub-battery modules; The frame member has a spring shape that is easy to stretch. Battery pack.

2. the two side portions of the frame member move along the longitudinal direction of the connecting portion together with the second sub-battery module; a center portion of the frame member extends along the longitudinal direction of the connecting portion together with the second sub-battery module; The battery pack according to claim 1 .

3. The frame member is made of one or more materials selected from the group consisting of glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP). The battery pack according to claim 2 .

4. the frame members include a first frame member and a second frame member; the first frame member is attached to an upper portion of the first sub-battery module and the pair of second sub-battery modules; the second frame member is attached to the lower portions of the first sub-battery module and the pair of second sub-battery modules; The battery pack according to any one of claims 1 to 3.

5. both end portions of the first frame member extend along outer surfaces of the pair of second sub-battery modules; both end portions of the second frame member extend along outer surfaces of the pair of second sub-battery modules; an end of the first frame member and an end of the second frame member are spaced apart from each other; The battery pack according to claim 4.

6. further including an end plate positioned between the frame member and the side portion of the pack frame; The battery pack according to any one of claims 1 to 3.

7. the end plates are in contact with outer surfaces of the frame members located on the outer surfaces of the pair of second sub-battery modules; The battery pack according to claim 6.

8. The pair of connecting portions penetrate the upper and lower parts of the end plate, respectively. The battery pack according to claim 7.

9. Both sides of the pair of connecting portions are bolted to the side surfaces of the pack frame, the first sub-battery module is bolted to the bottom surface of the pack frame; The battery pack according to claim 1 .

10. the first sub-battery module includes a first battery cell stack in which a plurality of first battery cells are stacked; the second sub-battery module includes a second battery cell stack in which a plurality of second battery cells are stacked; The battery pack according to claim 1 .

11. the first sub-battery module includes a pair of first module frames respectively attached to upper and lower portions of the first battery cell stack; the second sub-battery module includes a pair of second module frames respectively attached to upper and lower portions of the second battery cell stack; The battery pack according to claim 10.

12. the pair of connecting portions respectively pass through the pair of first module frames, each of the pair of second module frames; The battery pack according to claim 11.

13. Both side surfaces of the first battery cell stack and both side surfaces of the second battery cell stack are exposed to the outside. The battery pack according to claim 11.

14. a first fixing member is formed between the first module frame and the first battery cell stack; a second fixing member is formed between the second module frame and the second battery cell stack; The battery pack according to claim 11.

15. A device comprising the battery pack of claim 1.

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