Battery pack

Abstract

A battery pack according to an embodiment of the present invention may include a housing, at least one battery module accommodated in the housing, a venting portion provided in the housing to exhaust gas generated in the battery module, a filter disposed in front of the venting portion in the direction of gas flow, a scraper that removes foreign matter accumulated on the filter, and a driving portion that operates in response to the gas flow and moves the scraper back and forth.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0139552, filed October 26, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery pack capable of venting internal gas. [Background technology]

[0003] Rechargeable secondary batteries do not require replacement of battery cells, making them suitable for use as built-in battery cells. The stability and capacity of secondary batteries are rapidly improving, and they are being applied to a variety of devices.

[0004] For example, secondary batteries are widely used as energy sources for wireless mobile devices or wearable devices, which are small multi-functional products, and are also used as energy sources or energy storage devices (ESS) for electric vehicles and hybrid electric vehicles, which are presented as alternatives to conventional gasoline and diesel vehicles that cause air pollution.

[0005] In particular, in order to use secondary batteries as a large-capacity, high-power energy source, battery modules including a plurality of battery cells and battery packs including a plurality of such battery modules are used. As secondary batteries are used as such large-capacity, high-power energy sources, ensuring the safety of secondary batteries has become a major concern.

[0006] In the past, to prevent the lifespan of secondary batteries from being rapidly shortened due to temperature during long-term use, cooling systems were designed based on the heat generation amount according to the usage environment of the secondary battery and the reliable usage temperature. However, if one battery cell in a battery module or battery pack exceeds its critical temperature due to abnormal heat generation, thermal runaway (TR) may occur, causing thermal propagation (TP) to surrounding battery cells. This can lead to safety issues such as fire.

[0007] In order to prevent an excessive increase in the internal pressure of the battery pack due to a large amount of gas generated when a battery cell ignites, the battery pack is provided with a venting part for discharging the gas to the outside. In addition, such a venting part is generally provided with a filter for filtering ignitable particles and sparks to prevent flames from being discharged to the outside of the battery pack.

[0008] However, if the battery cell continues to catch fire, the filter may become clogged with a large amount of particles, which may prevent the gas from being expelled smoothly. Summary of the Invention [Problem to be solved by the invention]

[0009] One problem to be solved by the present invention is to provide a battery pack in which a scraper that prevents foreign matter from accumulating on a filter moves back and forth due to the flow of gas, thereby preventing the filter from becoming clogged. [Means for solving the problem]

[0010] A battery pack according to an embodiment of the present invention may include a housing, at least one battery module accommodated in the housing, a venting portion provided in the housing to exhaust gas generated from the battery module, a filter disposed in front of the venting portion in the direction of gas flow, a scraper that removes foreign matter accumulated on the filter, and a driving portion that operates in response to the gas flow and moves the scraper back and forth.

[0011] The drive unit can move the scraper in the overall length direction, the overall width direction, or the height direction of the battery pack.

[0012] The filter may have a slot formed therein that extends parallel to the direction of movement of the scraper.

[0013] The battery pack may further include a venting passage located within the housing and configured to guide gas generated in the battery module to the venting portion.

[0014] The housing may include an inner housing that accommodates the plurality of battery modules, and an outer housing that surrounds the inner housing and has the venting portion formed therein. The venting passage may be formed between the inner housing and the outer housing.

[0015] The driving unit may include a fan that rotates due to the flow of the gas, and a switching mechanism that switches the rotational force of the fan into a moving force for the scraper.

[0016] The scraper is movable in a direction parallel to the axis of rotation of the fan.

[0017] The switching mechanism may include a rotor that rotates about a rotation axis perpendicular to a rotation axis of the fan, and an arm that connects the rotor and the scraper.

[0018] The switching mechanism may further include a gear portion that transfers the rotational force of the fan to the rotational force of the rotor.

[0019] One end of the arm may be rotatably connected to the rotor at a position eccentric to the rotation axis of the rotor, and the other end of the arm may be rotatably connected to the scraper.

[0020] The rotor may have a first protrusion protruding from a position eccentric to a rotation axis of the rotor, the scraper may have a second protrusion protruding from the scraper, and the arm may have a first guide groove into which the first protrusion is inserted and which extends in a length direction of the arm, and a second guide groove into which the second protrusion is inserted and which extends in a length direction of the arm.

[0021] The scraper can move in a direction perpendicular to the rotation axis of the fan and the rotation axis of the rotor.

[0022] The battery pack may further include a guide portion for guiding movement of the scraper.

[0023] The scraper may include a connecting portion connected to the driving portion, a main body having a cleaning member protruding toward the filter, and an extension portion connecting the connecting portion and the main body, extending parallel to a moving direction of the scraper, and contacting the guide portion.

[0024] The scraper may include a connecting portion connected to the driving portion, extending parallel to a moving direction of the scraper and contacting the guide portion, and a main body connected to the connecting portion and including a cleaning member protruding toward the filter. [Effects of the Invention]

[0025] According to a preferred embodiment of the present invention, the scraper can be reciprocated by a drive unit that is actuated by the flow of gas, thereby removing foreign matter accumulated on the filter in response to the generation of gas and allowing the gas to pass through the filter and be smoothly exhausted.

[0026] In addition, the filter can be moved without consuming additional energy, and when gas is generated in the battery module due to a fire or the like, the filter can be automatically moved.

[0027] In addition, since the rotation speed of the fan included in the driving unit is proportional to the gas flow rate, the movement speed of the scraper may increase as the amount of gas generated in the battery module increases, so that even if the amount of gas and foreign matter generated in the battery module increases, foreign matter accumulated in the filter may be removed more quickly in proportion to the increase in the amount of gas and foreign matter.

[0028] Other effects that can be easily predicted by a person skilled in the art from the configurations according to the preferred embodiments of the present invention can also be included. [Brief explanation of the drawings]

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention to be given later, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in such drawings.

[0030] [Figure 1] 1 is a cross-sectional view schematically illustrating the interior of a battery pack according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a drive unit and a scraper according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram of a drive unit and a scraper according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031]

[0033] The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention can be realized in several different forms, and is not limited to or by the following examples.

[0032] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may unnecessarily obscure the gist of the present invention will be omitted, and when adding reference symbols to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0033] Furthermore, the terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concepts of terms in order to best explain his or her invention.

[0034] FIG. 1 is a cross-sectional view that schematically shows the inside of a battery pack according to one embodiment of the present invention.

[0035] A battery pack 1 according to one embodiment of the present invention may include a housing 10 and at least one, preferably a plurality of battery modules 20 housed in the housing 10 .

[0036] More specifically, the housing 10 may include an inner housing 11 that houses at least one battery module 20 and an outer housing 12 that surrounds the inner housing 11 .

[0037] For example, the outer housing 12 may include a lower plate, an outer peripheral wall, and an upper plate, and the inner housing 11 may include an inner peripheral wall connected to the lower plate and the upper plate of the outer housing 12. However, the present invention is not limited thereto.

[0038] A partition wall 13 may be provided inside the inner housing 11. The partition wall 13 may divide the inner space of the inner housing 11 into a plurality of chambers. A battery module 20 may be disposed in each chamber.

[0039] The partitions 13 may include first and second partitions that intersect with each other and cross the internal space of the inner housing 11. For example, as shown in Fig. 1, the partitions 13 may include a single first partition extending parallel to the entire length of the battery pack 1 and four second partitions extending parallel to the entire width of the battery pack 1. The number of first and second partitions may vary depending on the number and arrangement of the battery modules 20 housed in the inner housing 11.

[0040] The outer housing 12 may surround the inner housing 11. The outer housing 12 may form the exterior of the battery pack 1. A venting passage 31, which will be described later, may be formed between the outer housing 12 and the inner housing 11.

[0041] At least one battery module 20 may be provided, and preferably a plurality of battery modules 20 may be provided.

[0042] Each battery module 20 may include a module case and a plurality of battery cells (not shown) housed in the module case. The battery module 20 has a well-known configuration, and therefore a detailed description thereof will be omitted.

[0043] The plurality of battery modules 20 may be arranged in a predetermined array within the housing 10. More specifically, the plurality of battery modules 20 may be arranged in a plurality of chambers separated by partitions 13 within the inner housing 11. Therefore, when a thermal runaway or resulting fire occurs in one battery module 20, the flame or gas can be prevented from spreading to other nearby battery modules 20. In addition, thermal propagation (TP) between the plurality of battery modules 20 can be prevented.

[0044] The battery pack 1 may include a venting portion 30 provided in the housing 10 so that gas generated in the battery module 20 can be discharged.

[0045] The venting portion 30 may be provided on the outer housing 12. The venting portion 30 may be provided on the circumferential surface of the housing 10, more specifically, on the circumferential surface of the outer housing 12.

[0046] The venting part 30 may be configured to discharge gas generated in at least one of the plurality of battery modules 20 to the outside of the housing 10. The venting part 30 may communicate the inside and outside of the housing 10. The configuration of the venting part 30 is not limited. For example, the venting part 30 may include a passage or a hole through which gas passes.

[0047] The venting section 30 prevents the internal pressure of the housing 10 from increasing excessively by discharging gases caused by a fire or thermal runaway that occurs in the battery module 20 to the outside, thereby preventing the structure of the housing 10 from collapsing.

[0048] The battery pack 1 may further include a venting passage 31 located within the housing 10 to guide gas generated in the battery module 20 to the venting portion 30 .

[0049] For example, the venting passage 31 may be formed between the inner housing 11 and the outer housing 12. More specifically, the venting passage 31 may be formed between the outer surface of the inner housing 11 and the inner surface of the outer housing 12.

[0050] The inner housing 11 may be formed with a plurality of venting holes 14 that communicate with the venting passage 31. Each venting hole 14 may connect a chamber in which each battery module 20 is disposed to the venting passage 31. Therefore, if gas is generated due to a fire or thermal runaway in one battery module 20, the gas may flow to the venting passage 31 through the venting hole 14 of the chamber in which the one battery module 20 is disposed.

[0051] The battery pack 1 may include a filter 40 arranged in front of the venting section 30 in the direction of gas flow, a scraper 50 that removes foreign matter accumulated on the filter 40, and a drive section 60 that operates in response to the gas flow to move the scraper 50 back and forth.

[0052] The filter 40 may be located before the venting portion 30 in the gas flow direction. That is, the gas in the housing 10 may pass through the filter 40 and be discharged to the venting portion 30. The filter 40 may be disposed in the venting passage 31. The filter 40 may be connected to the venting portion 30, but is not limited thereto.

[0053] There is no limitation on the configuration of the filter 40. As an example, the filter 40 may include at least one of a porous mesh, a porous membrane, or a grille.

[0054] The filter 40 can filter out ignitable particles and sparks contained in the gas, thereby preventing flames from being discharged to the outside of the battery pack 1 through the venting part 30.

[0055] However, if gas is generated in the battery module 20 for a long period of time, the particles filtered by the filter 40 may clog the filter 40. Therefore, to prevent this problem, the scraper 50 can remove foreign matter accumulated inside the filter 40.

[0056] More specifically, the scraper 50 is reciprocated by the driving unit 60 to scrape off and remove foreign matter accumulated inside the filter 40. The driving unit 60 can also be operated by the flow of gas discharged to the venting unit 30. That is, the reciprocating movement of the scraper 50 can be performed by the flow of gas without any additional energy input.

[0057] The driving unit 60 can be connected to the scraper 50. The driving unit 60 can reciprocate the scraper 50 in the length direction or width direction of the filter 40. More specifically, the driving unit 60 can move the scraper 50 in the overall length direction, width direction, or height direction of the battery pack 1.

[0058] FIG. 2 is a schematic diagram of a drive unit and a scraper according to one embodiment of the present invention.

[0059] The driving unit 60 can be operated passively by the flow of gas instead of being actively operated. That is, the driving unit 60 can move the scraper 50 by the flow of gas. This allows the scraper 50 to be moved without consuming additional energy. Another advantage is that the scraper 50 is normally stationary, but when gas is generated in the battery module 20 due to a fire or the like, the scraper 50 can automatically move back and forth.

[0060] In this embodiment, the scraper 50 can move in the horizontal direction. More specifically, the scraper 50 can move in the direction of the entire length or width of the battery pack 1. More specifically, the scraper 50 can move in a direction parallel to the rotation axis of the fan 61.

[0061] The driving unit 60 may include a fan 61 that rotates due to the flow of gas, and a switching mechanism 62 that switches the rotational force of the fan 61 into a moving force for the scraper 50 .

[0062] The fan 61 may be disposed within the venting passage 31. The fan 61 may be disposed so as to rotate due to the flow of gas within the venting passage 31.

[0063] The switching mechanism 62 can connect the fan 61 and the scraper 50. The switching mechanism 62 can switch the rotational force of the fan 61 to the moving force of the scraper 50.

[0064] For example, the switching mechanism 62 may be a crank mechanism. More specifically, the switching mechanism 62 may include a rotor 65 that rotates about a rotation axis perpendicular to the rotation axis of the fan 61, and an arm 66 that connects the rotor 65 to the scraper 50. The switching mechanism 62 may further include gear units 63 and 64 that transmit the rotational force of the fan 61 to the rotational force of the rotor 65.

[0065] The gear units 63, 64 may include a first gear 63 connected to the fan 61 and a second gear 64 meshing with the first gear 63 and connected to the rotor 65. The rotation axes of the first gear 63 and the second gear 64 may be perpendicular to each other. The first gear 63 and the second gear 64 may be bevel gears.

[0066] The first gear 63 can rotate together with the fan 61, and the second gear 64 can rotate together with the rotor 65. However, this is not limiting, and it goes without saying that the gear units 63, 64 can also be configured to include additional gears.

[0067] The rotor 65 can be rotated by the rotational force of the fan 61 transmitted via the gear portions 63 and 64. The configuration of the rotor 65 is not limited. As an example, the rotor 65 can have a disk shape as shown in FIG. 2. As another example, the rotor 65 can have a cam shape.

[0068] One end of the arm 66 may be connected at an eccentric position relative to the rotation axis of the rotor 65. Both ends of the arm 66 may be rotatably connected to the rotor 65 and the scraper 50. For example, one end of the arm 66 may be hingedly connected to the rotor 65, and the other end may be hingedly connected to the scraper 50.

[0069] This allows the arm 66 to push and pull the scraper 50 in response to the rotation of the rotor 65, allowing the scraper 50 to move back and forth.

[0070] Therefore, when a gas flow occurs, the fan 61 rotates and the scraper 50 moves back and forth, periodically removing foreign matter accumulated on the filter 40 from inside the filter 40 .

[0071] Furthermore, because the rotation speed of the fan 61 is proportional to the gas flow rate, the movement speed of the scraper 50 can be increased as the amount of gas generated in the battery module 20 increases. This prevents the filter 40 from becoming completely clogged even if the amount of gas generated in the battery module 20 increases.

[0072] Meanwhile, the battery pack 1 may further include a guide portion 70 that guides the movement of the scraper 50. The guide portion 70 may support the scraper 50.

[0073] The guide portion 70 may be provided on the housing 10, more specifically, on the inner surface of the outer housing 12. However, the present invention is not limited to this.

[0074] The guide portion 70 can restrain the scraper 50 in directions other than the movement direction of the scraper 50. For example, when the drive portion 60 moves the scraper 50 in the left-right direction, the guide portion 70 can restrain the scraper 50 in the up-down direction and the front-back direction.

[0075] This allows the movement of the scraper 50 to be reliably guided, and the scraper 50 to be supported so as to move back and forth inside the filter 40.

[0076] Meanwhile, the filter 40 may have a slot 41 formed therein that extends parallel to the moving direction of the scraper 50. In this embodiment, the slot 41 formed in the filter 40 may be formed to extend horizontally, i.e., along the entire length or width of the battery pack 1.

[0077] Therefore, foreign matter accumulated around the slots 41 can be effectively removed by the scraper 50.

[0078] The scraper 50 may include a connecting portion 51 connected to the driving portion 60 and a main body 52 provided with a cleaning member 52 a protruding toward the filter 40 .

[0079] The linkage 51 may be coupled to the switching mechanism 62, more specifically, to the arm 66. As mentioned above, the arm 66 may be rotatably coupled to the linkage 51.

[0080] The body 52 may be elongated in a direction perpendicular to the movement direction of the scraper 50. For example, the scraper 50 may move horizontally, and the body 52 may be elongated in a vertical direction. The length of the body 52 may be longer than the filter 40 in that direction. Therefore, the reciprocating movement of the body 52 can completely remove foreign matter accumulated on the filter 40.

[0081] The main body 52 may be provided with a cleaning member 52a that protrudes toward the filter 40. The cleaning member 52a can come into contact with the filter 40 to scrape off foreign matter and the like that has accumulated on the filter 40. The configuration and material of the cleaning member 52a are not limited. For example, the cleaning member 52a may be formed of a brush or a rigid body.

[0082] The scraper 50 may further include an extension 53 connecting the connecting portion 51 and the main body 52. ​​The extension 53 may be connected to at least one end of the main body 52.

[0083] The extensions 53 may be positioned so as not to overlap the filter 40. For example, a pair of extensions 53 may be provided that overlap the upper and lower sides of the filter 40. This is because, as described above, the length of the main body 52 is formed to be longer than the filter 40 in that direction.

[0084] The extension portion 53 may extend in a direction parallel to the movement direction of the scraper 50. The extension portion 53 may contact the guide portion 70. Therefore, the movement direction of the scraper 50 may be limited to the length direction of the extension portion 53 by the guide portion 70.

[0085] However, the present invention is not limited thereto, and the scraper 50 may not include the extension 53, and the connecting part 51 and the main body 52 may be directly connected to each other. In this case, the connecting part 51 may extend in a direction parallel to the moving direction of the scraper 50 and may contact the guide part 70. That is, the connecting part 51 may function as the extension 53 instead.

[0086] FIG. 3 is a schematic diagram of a drive and scraper according to another embodiment of the present invention.

[0087] Below, the overlapping content with the above content will be cited, and the differences will be mainly explained.

[0088] In this embodiment, the scraper 50' can move in the vertical direction. More specifically, the scraper 50' can move in the height direction of the battery pack 1. More specifically, the scraper 50' can move in directions perpendicular to the rotation axis of the fan 61 and the rotation axis of the rotor 65.

[0089] The switching mechanism 62' according to this embodiment may include an arm 67 that connects the rotor 65 and the scraper 50'.

[0090] A first protrusion 65a may be formed to protrude from the rotor 65, and a second protrusion 51a may be formed to protrude from the scraper 50'. The first protrusion 65a may be formed at an eccentric position with respect to the rotation axis of the rotor 65. The arm 67 may be formed with a first guide groove 67a into which the first protrusion 65a is inserted, and a second guide groove 67b into which the second protrusion 51a is inserted. The first guide groove 67a and the second guide groove 67b may be formed to be elongated in the length direction of the arm 67.

[0091] The first guide groove 67a and the second guide groove 37b may be formed to penetrate the arm 67 as shown in Fig. 3. However, this is not limitative and the first guide groove 67a and the second guide groove 37b may be formed to a predetermined depth in the arm 67.

[0092] As a result, the first protrusion 65a moves within the first guide groove 67a as the rotor 65 rotates, and in conjunction with this, the second protrusion 51a moves within the second guide groove 67b, allowing the scraper 50' to reciprocate.

[0093] In addition, one point of the arm 67 may be rotatably fixed in position. For example, the one point may be located between the first guide groove 67a and the second guide groove 67b on the arm 67. For another example, the one point may be one end of the arm 67 adjacent to the first guide groove 67a.

[0094] Therefore, the angle of the arm 67 can be changed around the one point in accordance with the rotation of the rotor 65, and the other end of the arm 67 adjacent to the second guide groove 67b can repeatedly rise and fall, that is, the scraper 50' can move up and down.

[0095] The guide unit 70 can restrain the scraper 50' in directions other than the direction of movement of the scraper 50'. For example, when the drive unit 60 moves the scraper 50 in the up-down direction, the guide unit 70 can restrain the scraper 50 in the left-right direction and the front-back direction.

[0096] This allows the movement of the scraper 50 to be reliably guided, and the scraper 50 to be supported so as to move back and forth inside the filter 40.

[0097] The filter 40′ may have slots 41 extending parallel to the moving direction of the scraper 50′. In this embodiment, the slots 41 formed in the filter 40′ may be elongated in the vertical direction, i.e., the height direction of the battery pack 1.

[0098] Meanwhile, the scraper 50 may include a connecting portion 51 ′ connected to the driving portion 60 and a main body 52 ′ having a cleaning portion 52 a protruding toward the filter 40 .

[0099] The connecting portion 51 may be connected to the switching mechanism 62′, more specifically, to the arm 67. As described above, the connecting portion 51′ has a second protrusion 51a formed thereon, and the second protrusion 51a may be inserted into the second guide groove 67b of the arm 67.

[0100] The body 52' may be elongated in a direction perpendicular to the movement direction of the scraper 50'. For example, the scraper 50' may move vertically, and the body 52' may be elongated in a horizontal direction. The length of the body 52' may be longer than the length of the filter 40' in that direction. Therefore, the reciprocating movement of the body 52' may completely remove foreign matter accumulated on the filter 40'.

[0101] The connecting portion 51' may extend in a direction parallel to the moving direction of the scraper 50' and may contact the guide portion 70. Therefore, the moving direction of the scraper 50' may be limited to the length direction of the connecting portion 51' by the guide portion 70.

[0102] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations are possible by a person having ordinary knowledge in the technical field to which the present invention pertains, without departing from the essential characteristics of the present invention.

[0103] Therefore, the embodiments disclosed in the present invention are for illustrative purposes only and are not intended to limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0104] The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0105] 1: Battery pack 10: Housing 11: Inner housing 12: Outer housing 13: Bulkhead 14: Venting Hall 20: Battery module 30: Venting section 40: Filter 50: Scraper 51:Connection part 52: Main body 52a: cleaning member 53: Extension part 60: Drive unit 61: Fan 62: Switching mechanism 65:Rotor 66: Arm 70: Guide section

Claims

1. Housing and at least one battery module housed within the housing; a vent provided in the housing to allow gas generated in the battery module to be discharged; a filter disposed before the venting portion in the gas flow direction; a scraper for removing foreign matter accumulated on the filter; a drive unit that is operated by the flow of the gas and causes the scraper to reciprocate.

2. The battery pack according to claim 1 , wherein the drive unit moves the scraper in a direction of the entire length, width, or height of the battery pack.

3. The battery pack according to claim 1 , wherein the filter has a slot formed therein that extends parallel to a moving direction of the scraper.

4. The battery pack of claim 1 , further comprising a venting passage located within the housing for guiding gas generated in the battery module to the venting portion.

5. The housing includes: an inner housing that accommodates a plurality of the battery modules; an outer housing surrounding the inner housing and including the venting portion; The battery pack according to claim 4 , wherein the venting passage is formed between the inner housing and the outer housing.

6. The drive unit is a fan that rotates due to the flow of the gas; The battery pack according to claim 1 , further comprising: a switching mechanism that switches a rotational force of the fan to a moving force of the scraper.

7. The battery pack according to claim 6 , wherein the scraper moves in a direction parallel to a rotation axis of the fan.

8. The switching mechanism comprises: a rotor that rotates around a rotation axis perpendicular to the rotation axis of the fan; The battery pack of claim 6 , further comprising an arm connecting the rotor and the scraper.

9. The switching mechanism comprises: The battery pack according to claim 8 , further comprising a gear portion that transmits the rotational force of the fan to the rotational force of the rotor.

10. one end of the arm is rotatably connected to the rotor at a position eccentric to a rotation axis of the rotor, The battery pack according to claim 8 , wherein the other end of the arm is rotatably coupled to the scraper.

11. a first protrusion is formed on the rotor at a position eccentric to a rotation axis of the rotor; The scraper has a second protrusion formed thereon, The arm has: a first guide groove into which the first protrusion is inserted and which extends in the length direction of the arm; The battery pack according to claim 8 , further comprising a second guide groove, into which the second protrusion is inserted and which extends in the length direction of the arm.

12. The battery pack according to claim 8 , wherein the scraper moves in a direction perpendicular to each of the rotation axis of the fan and the rotation axis of the rotor.

13. The battery pack according to claim 1 , further comprising a guide portion that guides the movement of the scraper.

14. The scraper is a connecting portion connected to the driving portion; a main body provided with a cleaning member protruding toward the filter; The battery pack according to claim 13 , further comprising: an extension portion that connects the connecting portion and the main body, extends parallel to the moving direction of the scraper, and contacts the guide portion.

15. The scraper is a connecting portion connected to the driving portion, extending parallel to the moving direction of the scraper and contacting the guide portion; The battery pack according to claim 13 , further comprising: a main body connected to the connecting portion and provided with a cleaning member protruding toward the filter.

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