Battery pack

Abstract

The present invention discloses a battery pack. A battery pack according to one embodiment of the present invention includes a base plate, a first battery module provided on the upper surface of the base plate, a partition wall provided on the upper surface of the base plate and having an opening facing the first battery module, and a movable wall provided to cover the opening and be movable.

Description

Technical Field

[0001] The present invention relates to a battery pack.

[0002] This application claims priority based on Korean Patent Application No. 10-2024-0034480 filed on March 12, 2024, and all the contents disclosed in the specification and drawings of the application are incorporated into this application.

Background Art

[0003] As the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has rapidly increased and the commercialization of robots, electric vehicles, etc. has become full-scale, research on high-performance secondary batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries are attracting attention because they have almost no memory effect compared to nickel-based secondary batteries, so they can be freely charged and discharged, have a very low self-discharge rate, and have a high energy density.

[0005] Such lithium secondary batteries mainly use a lithium-based oxide and a carbon material as a positive electrode active material and a negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate coated with such a positive electrode active material and a negative electrode plate coated with a negative electrode active material are arranged with a separator interposed therebetween, and an exterior material that hermetically houses the electrode assembly together with an electrolytic solution, for example, a battery case.

[0006] Generally, lithium secondary batteries can be divided into a can-type secondary battery in which an electrode assembly is housed in a metal can and a pouch-type secondary battery in which an electrode assembly is housed in a pouch made of an aluminum laminate sheet according to the shape of the exterior material.

[0007] In recent years, secondary batteries have been widely used not only in small devices such as portable electronic devices, but also in medium and large-scale devices such as electric vehicles and energy storage systems (ESS), for propulsion and energy storage. These secondary batteries are electrically connected and housed together inside a module case to form a single battery module. Furthermore, multiple such battery modules are connected to form a single battery pack.

[0008] However, when multiple secondary batteries (battery cells) or multiple battery modules are densely packed into a small space, they can be vulnerable to thermal events. In particular, if an event such as thermal runaway occurs in one battery cell, high-temperature gases, flames, and heat may be generated. If such gases, flames, and heat are transferred to other battery cells contained within the same battery module, an explosive chain reaction such as thermal propagation can occur. Furthermore, such a chain reaction can not only cause accidents such as fires and explosions in the battery module in question, but can also cause fires and explosions in other battery modules.

[0009] Furthermore, in the case of medium to large battery packs, such as those found in electric vehicles, the risk of chain reactions is even higher because they contain a large number of battery cells and battery modules in an attempt to increase output and / or capacity. Moreover, in the case of battery packs installed in electric vehicles, there may be users such as drivers in the vicinity. Therefore, if a thermal event occurring in a particular battery cell or module cannot be properly controlled and a chain reaction occurs, it could lead to not only significant property damage but also loss of life. For this reason, it is necessary to improve the thermal safety of battery packs by properly controlling thermal events generated in battery cells and modules. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to solve the problems described above and other problems.

[0011] Another object of the present invention is to provide a battery pack with improved safety when a thermal event occurs.

[0012] Another object of the present invention is to provide a battery pack that can expand the vent space around the battery module to suppress heat propagation when a thermal event occurs.

[0013] Another object of the present invention is to provide a battery pack that can expand the vent space around the battery module to delay the accumulation of thermal energy when a thermal event occurs. [Means for solving the problem]

[0014] To achieve the above objective, a battery pack according to one aspect of the present invention includes a base plate, a first battery module provided on the upper surface of the base plate, a fixed wall provided on the upper surface of the base plate and having an opening facing the first battery module, and a partition wall including a movable wall that covers the opening and is movable.

[0015] Furthermore, the movable wall can move in a direction that brings it closer to the first battery module or away from the first battery module.

[0016] Furthermore, the movable wall may move away from the first battery module when a thermal event occurs in the first battery module.

[0017] Furthermore, the first battery module may include a module case that provides internal space, and a plurality of battery cells housed inside the module case.

[0018] It further includes a second battery module provided on the upper surface of the base plate, and the partition wall may be located between the first battery module and the second battery module.

[0019] The partition wall further includes a first stopper protruding inside the opening and a second stopper protruding inside the opening and spaced apart from the first stopper along the thickness direction of the fixed wall, and the movable wall may be located between the first stopper and the second stopper.

[0020] The first stopper may extend along the periphery of the opening.

[0021] The partition wall may further include a first elastic member located between the first stopper and the movable wall and providing a restoring force to the movable wall.

[0022] The partition wall may further include a second elastic member located between the second stopper and the movable wall and providing a restoring force to the movable wall.

[0023] The elastic coefficient of the first elastic member and the elastic coefficient of the second elastic member may be configured to be substantially equal.

[0024] The partition wall may further include an adhesive member that couples the movable wall to the opening.

[0025] The movable wall may be configured to have a lower thermal conductivity than the fixed wall.

[0026] The movable wall may include a first sheet and a second sheet coupled to the first sheet and made of a material different from that of the first sheet.

[0027] The first sheet may include a mica material.

[0028] Further, the second sheet may include a silicone or aerogel material.

[0029] An automobile according to another aspect of the present invention includes a battery pack according to an aspect of the present invention.

Advantages of the Invention

[0030] According to one aspect of the present invention, the thermal safety of the battery pack can be improved.

[0031] According to one aspect of the present invention, heat propagation can be suppressed.

[0032] According to one aspect of the present invention, when a thermal event occurs, the accumulation of thermal energy can be delayed.

[0033] The following drawings attached to this specification illustrate preferred embodiments of the present invention and are for the purpose of facilitating a further understanding of the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention is not to be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0034] [Figure 1] It is a diagram showing a battery pack according to an embodiment of the present invention. [Figure 2] It is a diagram showing a separated partial configuration of the battery pack of FIG. 1. [Figure 3] It is a diagram showing a separated partial configuration of the battery module of FIG. 2. [Figure 4] It is a diagram showing a partial configuration of the battery pack of FIG. 1. [Figure 5] It is a diagram showing a cross-sectional configuration along the cutting line A-A' or the cutting line B-B' of FIG. 1. [Figure 6] It is a diagram showing the state in which a thermal event occurs in FIG. 5. [Figure 7] It is a diagram showing the state in which a thermal event occurs in FIG. 5. [Figure 8] This figure shows the cross-sectional configuration along the cutting line C-C' in Figure 1. [Figure 9] This figure shows the deformed form of Figure 5. [Figure 10] Figure 9 shows how a thermal event occurred. [Figure 11] This figure shows the movable wall in Figure 2. [Figure 12] This diagram shows a separate view of a portion of the movable wall structure in Figure 11. [Figure 13] This figure shows the cross-sectional configuration along the cutting line D-D' in Figure 11. [Modes for carrying out the invention]

[0035] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims shall not be interpreted in a manner limited to their general and dictionary meanings, but in accordance with the principle that inventors themselves may appropriately define the concepts of terms in order to best describe their invention, and shall be interpreted in a manner and concept corresponding to the technical idea of ​​the present invention.

[0036] 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 invention. It should be understood that there are various equivalents and modifications that can substitute for them at the time of this application.

[0037] Figure 1 shows a battery pack according to one embodiment of the present invention, Figure 2 shows a partial configuration of the battery pack in Figure 1 separated, Figure 3 shows a partial configuration of battery modules 200, 201, 202, 203, and 204 in Figure 2 separated, Figure 4 shows a partial configuration of the battery pack in Figure 1, and Figure 5 shows a cross-sectional configuration along the cutting line A-A' or cutting line B-B' in Figure 1.

[0038] Referring to Figures 1 to 5, a battery pack according to one embodiment of the present invention may include a base plate 110, battery modules 200, 201, 202, 203, 204, and a partition wall 300.

[0039] The base plate 110 may be rectangular in shape. The base plate 110 may be flat. The base plate 110 may form the exterior of the battery pack. The base plate 110 may provide the internal space of the battery pack.

[0040] Multiple battery modules 200, 201, 202, 203, and 204 may be provided. Battery modules 200, 201, 202, 203, and 204 may be installed, fastened, coupled, fixed, or attached to the upper surface of the base plate 110.

[0041] The partition wall 300 may include a first partition wall 301 and a second partition wall 302. Multiple partition walls 300 may be provided. The partition wall 300 may be installed, fastened, fixed, joined, or attached to the upper surface of the base plate 110. The partition wall 300 may partition the internal space of the battery pack. Battery modules 200, 201, 202, 203, and 204 may be located in the space partitioned by the partition wall 300, respectively.

[0042] The partition wall 300 may include a fixed wall 310 and a movable wall 320. The fixed wall 310 may be installed, fastened, fixed, joined, or attached to the upper surface of the plate. The fixed wall 310 may also have an opening 313. The opening 313 may be rectangular in shape. The opening 313 may extend along the longitudinal direction of the partition wall 300.

[0043] The movable wall 320 can cover the opening 313. The movable wall 320 can also be installed in or connected to the opening 313. The movable wall 320 can be movably provided.

[0044] Furthermore, the partition wall 300, fixed wall 310, opening 313, or movable wall 320 may face at least one side of the battery modules 200, 201, 202, 203, and 204.

[0045] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. When a thermal event occurs, vent gas g may be discharged from the battery modules 200, 201, 202, 203, and 204. At this time, the movable wall 320 moves, expanding the space surrounding the battery modules 200, 201, 202, 203, and 204. This ensures a vent space and slows down the rate at which thermal energy accumulates in the space surrounding the battery modules 200, 201, 202, 203, and 204. Furthermore, it can delay or suppress heat propagation inside the battery pack.

[0046] Referring to Figures 1 to 5, a battery pack according to one embodiment of the present invention may include a first partition wall 301, a second partition wall 302, a side wall 120, and a pack cover 150.

[0047] The side walls 120 can be installed, fastened, joined, fixed, or attached to the upper surface of the base plate 110. Four side walls 120 may be provided. The side walls 120 may be arranged along the periphery of the base plate 110. The side walls 120 may form the exterior of the battery pack. The side walls 120 may provide internal space.

[0048] The second partition wall 302 may extend for a long distance in the front-to-back direction. The second partition wall 302 may divide the interior space into a left-side space and a right-side space. The first partition wall 301 may extend for a long distance in the left-to-right direction. There may be four first partition walls 301 in the left-side space and four in the right-side space. Multiple first partition walls 301 may be arranged in the front-to-back direction.

[0049] Battery modules 200, 201, 202, 203, and 204 may be surrounded by a side wall 120, a first partition wall 301, and a second partition wall 302.

[0050] The pack cover 150 may be rectangular or flat. The pack cover 150 may form the exterior of the battery pack. The pack cover 150 may cover the internal space of the battery pack. The pack cover 150 may be installed, fastened, coupled, fixed, or attached to the side wall 120. The pack cover 150 may also cover the top surfaces of the battery modules 200, 201, 202, 203, and 204.

[0051] Referring to Figures 1 to 5, multiple battery modules 200, 201, 202, 203, and 204 may be provided. Each battery module 200, 201, 202, 203, and 204 may include a module case 210, a battery cell 220, an end cover 230, and a heat conductive member 240. The module case 210 may be rectangular parallelepiped. The module case 210 may have an open left and right side. The module case 210 may form the external appearance of the battery modules 200, 201, 202, 203, and 204. The module case 210 may provide internal space.

[0052] The battery cell 220 can be housed inside the module case 210. Multiple battery cells 220 may be provided. In this case, the battery cell 220 may represent a secondary battery. The battery cell 220 may also be pouch-type. Multiple battery cells 220 may be stacked or arranged along the front-to-back direction.

[0053] The heat conduction member 240 may be located between the multiple battery cells 220 and the module case 210. The heat conduction member 240 may be located below the multiple battery cells 220. The heat conduction member 240 may be made of resin. The heat conduction member 240 may also fix the multiple battery cells 220 to the module case 210. The heat conduction member 240 may also transfer heat generated from the multiple battery cells 220 to the module case 210.

[0054] The end covers 230 may be provided in pairs. Each pair of end covers 230 may be coupled, fastened, fixed, or attached to the left and right sides of the module case 210, respectively. The end covers 230 may form the appearance of the battery modules 200, 201, 202, 203, and 204.

[0055] Referring to Figures 1 to 5, a battery pack according to one embodiment of the present invention may include a fastening member 160. The fastening member 160 may penetrate the base plate 110. The fastening member 160 may also be inserted into the fixed wall 310 of the partition wall 300. The fastening member 160 can install, fasten, connect, fix, or attach the partition wall 300 and the base plate 110.

[0056] According to this configuration of the present invention, the fixed wall 310 of the partition wall 300 can be stably fixed.

[0057] Referring to Figures 1 to 5, a partition wall 300 of a battery pack according to one embodiment of the present invention may be located between two adjacent battery modules 200, 201, 202, 203, and 204. For example, the first partition wall 301 may be located between the second battery module 202 and the third battery module 203. The movable wall 320 may move between the second battery module 202 and the third battery module 203.

[0058] Furthermore, the second partition wall 302 may be located between the second battery module 202 and the fourth battery module 204. The movable wall 320 may move between the second battery module 202 and the fourth battery module 204.

[0059] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The partition wall 300 can expand the vent space between adjacent battery modules 200, 201, 202, 203, and 204.

[0060] Figures 6 and 7 show the thermal event that occurred in Figure 5. Referring to Figures 5 to 7, the movable wall 320 of the battery pack according to one embodiment of the present invention may be configured to move in a direction toward or toward the second battery module 202.

[0061] For example, the movable wall 320 of the first partition wall 301 can expand the vent space of the second battery module 202 by moving toward the third battery module 203. Alternatively, the movable wall 320 of the first partition wall 301 can expand the vent space of the third battery module 203 by moving toward the second battery module 202.

[0062] Furthermore, the movable wall 320 of the second partition wall 302 can expand the vent space of the second battery module 202 by moving toward the fourth battery module 204. Alternatively, the movable wall 320 of the second partition wall 302 can expand the vent space of the fourth battery module 204 by moving toward the second battery module 202.

[0063] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The partition wall 300 can expand the vent space between adjacent battery modules 200, 201, 202, 203, and 204.

[0064] Referring to Figures 5 to 7, the movable wall 320 of the battery pack according to one embodiment of the present invention may move away from the battery modules 200, 201, 202, 203, and 204 where a thermal event occurred when the thermal event occurred.

[0065] For example, when a thermal event occurs in the second battery module 202, the movable wall 320 of the first partition wall 301 can move toward the third battery module 203, thereby expanding the vent space of the second battery module 202. Alternatively, when a thermal event occurs in the third battery module 203, the movable wall 320 of the first partition wall 301 can move toward the second battery module 202, thereby expanding the vent space of the third battery module 203.

[0066] Furthermore, when a thermal event occurs in the second battery module 202, the movable wall 320 of the second partition wall 302 can move toward the fourth battery module 204, thereby expanding the vent space of the second battery module 202. Alternatively, when a thermal event occurs in the fourth battery module 204, the movable wall 320 of the second partition wall 302 can move toward the second battery module 202, thereby expanding the vent space of the fourth battery module 204.

[0067] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The partition wall 300 can expand the vent space between adjacent battery modules 200, 201, 202, 203, and 204.

[0068] Referring to Figures 5 to 7, the partition wall 300 of the battery pack according to one embodiment of the present invention may include a first stopper 311 and a second stopper 312. The first stopper 311 may protrude inward into the opening 313. The second stopper 312 may protrude inward into the opening 313. The first stopper 311 and the second stopper 312 may be spaced apart along the thickness direction of the fixed wall 310. Also, the first stopper 311 and the second stopper 312 may be positioned opposite each other.

[0069] The movable wall 320 may be located between the first stopper 311 and the second stopper 312. The movable wall 320 may move between the first stopper 311 and the second stopper 312. The first stopper 311 and the second stopper 312 may limit the range of movement of the movable wall 320. In addition, the first stopper 311 and the second stopper 312 may limit the range of movement of the movable wall 320 so that it does not move beyond the opening 313.

[0070] With this configuration of the present invention, the movable wall 320 can maintain a stable position in the opening 313 while expanding the vent space.

[0071] Referring to Figures 5 to 7, the first stopper 311 of the battery pack according to one embodiment of the present invention may extend along the periphery of the opening 313. The first stopper 311 may be rectangular in shape. A second stopper 312 may also extend along the periphery of the opening 313. The second stopper 312 may be rectangular in shape.

[0072] With this configuration of the present invention, the first stopper 311 and the second stopper 312 can stably maintain the mounting state of the movable wall 320.

[0073] Referring to Figures 5 to 7, a battery pack according to one embodiment of the present invention may include a first elastic member 331. The first elastic member 331 may be located between the first stopper 311 and the movable wall 320. The first elastic member 331 may provide a restoring force to the movable wall 320. One end of the first elastic member 331 may be coupled, fixed, attached, or fastened to the movable wall 320. The other end of the first elastic member 331 may be coupled, fixed, attached, or fastened to the first stopper 311. For example, the first elastic member 331 may be a spring. Multiple first elastic members 331 may be provided, and the multiple first elastic members may be arranged along the periphery of the first stopper 311.

[0074] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The movable wall 320 can stably expand the vent space by the first elastic member 331.

[0075] Referring to Figures 5 to 7, a battery pack according to one embodiment of the present invention may include a second elastic member 332. The second elastic member 332 may be located between the second stopper 312 and the movable wall 320. The second elastic member 332 may provide a restoring force to the movable wall 320. One end of the second elastic member 332 may be coupled, fixed, attached, or fastened to the movable wall 320. The other end of the second elastic member 332 may be coupled, fixed, attached, or fastened to the second stopper 312. For example, the second elastic member 332 may be a spring. Multiple second elastic members 332 may be provided, and the multiple second elastic members may be arranged along the periphery of the second stopper 312.

[0076] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The movable wall 320 can stably expand the vent space by the second elastic member 332.

[0077] Referring to Figures 5 to 7, the elastic modulus of the first elastic member 331 and the elastic modulus of the second elastic member 332 of the battery pack according to one embodiment of the present invention can be configured to be substantially equal.

[0078] According to this configuration of the present invention, the movable wall 320 can be supported while maintaining a stable equilibrium state.

[0079] Figure 8 shows a cross-sectional configuration along the cutting line C-C' in Figure 1. Referring to Figure 8, each of the multiple first partition walls 301 and second partition walls 302 may include a movable wall 320. For example, when a thermal event occurs in the second battery module 202, the movable wall 320 between the second battery module 202 and the third battery module 203 can expand the vent space. Also, the movable wall 320 between the second battery module 202 and the first battery module 201 can expand the vent space. Furthermore, the movable wall 320 between the second battery module 202 and the fourth battery module 204 can expand the vent space.

[0080] Figure 9 shows the deformation of Figure 5, and Figure 10 shows how the thermal event occurred in Figure 9.

[0081] Referring to Figures 8 to 10, a partition wall 300 of a battery pack according to another embodiment of the present invention may further include an adhesive member 340 for connecting, fixing, or attaching a movable wall 320 to the opening 313. The adhesive member 340 may be positioned along the periphery of the movable wall 320. The adhesive member 340 may also include a material that melts at a relatively low temperature. When a thermal event occurs in battery modules 200, 201, 202, 203, and 204, the adhesive member 340 can be easily melted by the vent gas g. This allows the movable wall 320 to be separated from the opening 313. For example, the separated movable wall 320 may move away from the third battery module 203 or the fourth battery module 204.

[0082] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. The movable wall 320, which is stably installed and fixed in the opening 313 by the adhesive member 340, can expand the vent space when a thermal event occurs.

[0083] Figure 11 shows the movable wall 320 of Figure 2, Figure 12 shows a separate view of a part of the movable wall 320 of Figure 11, and Figure 13 shows the cross-sectional configuration along the cutting line D-D' of Figure 11.

[0084] Referring to Figures 11 to 13, the movable wall 320 of the battery pack according to one embodiment of the present invention may include multiple sheets.

[0085] The movable wall 320 may be configured to have a lower thermal conductivity than the fixed wall 310. The movable wall 320 may include a first sheet 321, a second sheet 322, and a third sheet 323. The second sheet 322 may be located between the first sheet 321 and the third sheet 323. One side of the second sheet 322 may be bonded to the first sheet 321. The third sheet 323 may be bonded to the other side of the second sheet 322. The first sheet 321 and the second sheet 322 may be made of different materials. The second sheet 322 and the third sheet 323 may be made of different materials.

[0086] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. Because the movable wall 320 is made of composite material, it is possible to expand the vent space while stably blocking heat propagation.

[0087] Referring to Figures 11 to 13, the first sheet 321 or the third sheet 323 of the battery pack according to one embodiment of the present invention may include a material having high fire resistance or heat resistance. For example, the first sheet 321 or the third sheet 323 may include mica material. In this case, the mica material may be a material with high hardness. Alternatively, the first sheet 321 or the third sheet 323 may include steel material.

[0088] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. Because the first sheet 321 or the third sheet 323 of the movable wall 320 has high fire resistance or heat resistance, the movable wall 320 can maintain a stable connection to the opening 313 while expanding the vent space.

[0089] Referring to Figures 11 to 13, the second sheet 322 of the battery pack according to one embodiment of the present invention may include a material having high thermal insulation properties. For example, the second sheet 322 may include a silicone or aerogel material.

[0090] According to this configuration of the present invention, the thermal safety of the battery pack can be improved. Because the second sheet 322 of the movable wall 320 has high thermal insulation properties, the movable wall 320 can stably block heat propagation while expanding the vent space.

[0091] Furthermore, a battery pack according to one embodiment of the present invention may further include a variety of components, such as a battery management system (BMS), busbars, relays, current sensors, and other components of a battery pack known at the time of filing the present invention.

[0092] An automobile according to one embodiment of the present invention includes the battery pack according to the present embodiment of the present invention described above. The battery pack according to one embodiment of the present invention may be applied to automobiles such as electric vehicles and hybrid vehicles. Furthermore, an automobile according to one embodiment of the present invention may further include a variety of other components included in the automobile in addition to such a battery pack, such as a vehicle body, motors, and control devices such as an electronic control unit (ECU).

[0093] On the other hand, while terms indicating direction such as up, down, left, right, front, and back are used in this specification, these terms are used for convenience of explanation, and it is obvious to those skilled in the art that they can change depending on the position of the object being examined, the position of the observer, etc.

[0094] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

Claims

1. base plate and A first battery module provided on the upper surface of the base plate, The base plate includes a fixed wall provided on the upper surface of the base plate and having an opening facing the first battery module, and a partition wall including a movable wall that covers the opening and is movable, The battery pack further includes an adhesive member that connects the movable wall to the opening, wherein the partition wall is a partition wall.

2. The battery pack according to claim 1, wherein the movable wall is movable in a direction toward or toward the first battery module.

3. The battery pack according to claim 2, wherein the movable wall moves in a direction away from the first battery module when a thermal event occurs in the first battery module.

4. The first battery module is, A modular case that provides internal space, The battery pack according to claim 1, comprising a plurality of battery cells housed inside the module case.

5. The system further includes a second battery module provided on the upper surface of the base plate, The battery pack according to claim 1, wherein the partition wall is located between the first battery module and the second battery module.

6. The aforementioned partition wall is A first stopper protruding inward from the opening, The present invention further includes a second stopper that protrudes inward from the opening and is spaced apart from the first stopper along the thickness direction of the fixed wall, The battery pack according to claim 1, wherein the movable wall is located between the first stopper and the second stopper.

7. The battery pack according to claim 6, wherein the first stopper extends along the periphery of the opening.

8. The battery pack according to claim 6, wherein the partition wall further includes a first elastic member located between the first stopper and the movable wall, and providing a restoring force to the movable wall.

9. The battery pack according to claim 8, wherein the partition wall further includes a second elastic member located between the second stopper and the movable wall, and providing a restoring force to the movable wall.

10. The battery pack according to claim 9, wherein the elastic modulus of the first elastic member and the elastic modulus of the second elastic member are substantially equal.

11. The battery pack according to claim 1, wherein the movable wall is configured to have a lower thermal conductivity than the fixed wall.

12. The aforementioned movable wall is The first sheet and, The battery pack according to claim 1, comprising: a second sheet bonded to the first sheet and made of a different material from the first sheet.

13. The battery pack according to claim 12, wherein the first sheet comprises a mica material.

14. The battery pack according to claim 12, wherein the second sheet comprises a silicone or aerogel material.

15. An automobile comprising a battery pack according to any one of claims 1 to 14.

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