Battery pack

Abstract

The utility model relates to the field of battery pack structures, and particularly discloses a battery pack which comprises a shell, an upper mounting frame, a lower mounting frame and a battery cell assembly, the upper mounting frame and the lower mounting frame are arranged in the shell at intervals, the battery cell assembly is arranged between the upper mounting frame and the lower mounting frame, the shell is provided with a first surface and a second surface, an air inlet area is arranged on the first surface, and an air outlet area is arranged on the second surface. And a separator is arranged in the shell and is arranged on one side of the air inlet area. The separator can guide the cooling air flowing path entering the shell, so that the cooling air passes through the front end area of the battery cell assembly, then detours to the rear end area and then is led out from the air outlet (the air outlet is close to the rear end area of the battery cell assembly); flowing cooling air can be in full contact with the battery cell units in the front end area and the rear end area, and the cooling effect on the battery cell assembly is improved.

Description

Technical Field

[0001] This application relates to the field of battery pack structures, and more particularly to a battery pack. Background Technology

[0002] The battery pack is mainly used as a power source for power tools. It contains a battery cell assembly, which includes multiple rechargeable battery cell units. These battery cell units are arranged side by side in the battery pack housing with alternating positive and negative terminals. When the battery pack is low on power, it needs to be charged on a dedicated charger. The battery pack generates heat during the charging process, so heat dissipation is required during the charging process.

[0003] Based on an understanding of the relevant technologies, although some battery packs are equipped with heat dissipation structures that form heat dissipation channels inside the battery pack, the cooling air may not make proper contact with some of the battery cells after entering the heat dissipation channels through the air inlets on the battery pack, resulting in poor heat dissipation. Utility Model Content

[0004] The purpose of at least one specific embodiment of this utility model is to overcome the defects of the prior art and provide a battery pack.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A battery pack, comprising:

[0007] case;

[0008] The upper mounting bracket and the lower mounting bracket are spaced apart inside the housing.

[0009] The battery cell assembly is installed inside the housing and located between the upper mounting bracket and the lower mounting bracket;

[0010] The casing has an air inlet area and an air outlet area;

[0011] An isolation component is installed inside the housing, and the air inlet area, the isolation component, and the air outlet area form a heat dissipation channel.

[0012] Furthermore, the housing has adjacent first and second surfaces, which are staggered, with the air inlet area located on the first surface and the air outlet area located on the second surface.

[0013] Using the common edge of the first surface and the second surface as a reference line, the projection of the air inlet area onto the reference line is the first projection with a length of L1, and the projection of the air outlet area onto the reference line is the second projection with a length of L2. The overlap length of the first projection and the second projection is L12, where L12 < L1 and L12 < L2.

[0014] Furthermore, the first surface has multiple air inlets located in the air inlet area, and the second surface has multiple air outlets located in the air outlet area.

[0015] Furthermore, the battery cell assembly includes a first side portion, a second side portion, a third side portion, a middle portion, and a top portion;

[0016] The air intake area is close to the first side surface, and the air outlet area is close to the third side surface and located above the top.

[0017] The heat dissipation channel passes through the first side, the second side, the middle, and the third side in sequence, with the air inlet and air outlet at the two ends of the heat dissipation channel, respectively.

[0018] The first side face, the isolation member, and the inner wall of the housing form an air inlet cavity, and the third side face, the isolation member, and the inner wall of the housing form an air outlet cavity. The air inlet cavity and the air outlet cavity are separated by the isolation member. The air inlet cavity is connected to the air inlet, and the air outlet cavity is connected to the air outlet.

[0019] Cooling air flowing in from the air inlet enters the air inlet cavity, passes over the first side section, enters the second side section and the middle section, and flows out from the third side section. The flowing-out cooling air enters the air outlet cavity and is discharged from the air outlet.

[0020] Furthermore, the plane containing the top is perpendicular to the plane containing the first side face.

[0021] Furthermore, the battery cell assembly includes several battery cell units, with the upper mounting bracket and the lower mounting bracket connected to the two ends of each battery cell unit, respectively.

[0022] Furthermore, a flow-blocking element is provided between two adjacent battery cell units on the first side. The flow-blocking element is adapted to block the flow between the two adjacent battery cell units. The flow-blocking element is located inside the air inlet cavity and is disposed on one side of the isolation element.

[0023] Furthermore, the cell assembly has two first side faces, and the connection between the current-blocking elements on the two first side faces divides the cell assembly into a front-end region and a rear-end region.

[0024] A portion of the middle section and the second side section are located within the front end area, while a portion of the middle section and the third side section are located within the rear end area.

[0025] After the cooling air flows into the air inlet and enters the air inlet cavity, the cooling air flows from both sides of the battery cell assembly to the front end area, then detours from the front end area to the rear end area, and finally enters the air outlet cavity and is discharged from the air outlet.

[0026] Furthermore, the isolation component includes a first isolation part connected to the upper mounting bracket and a second isolation part connected to the lower mounting bracket, with the ends of the first isolation part and the second isolation part mating with each other;

[0027] After docking, the first and second isolation sections are locked together by fasteners and supported between the upper and lower mounting brackets.

[0028] Furthermore, a bonding portion is provided on one side of the first isolation portion and the second isolation portion. The bonding portion is located between two adjacent cell units and is bonded to the surface of the cell unit. The bonding portion is adapted to seal the gap between the two adjacent cell units.

[0029] On the other side of the first isolation section and the second isolation section, there is a locking part that engages with the protruding ribs on the inner wall of the housing.

[0030] Furthermore, the flow-blocking component includes a first flow-blocking part connected to the upper mounting bracket and a second flow-blocking part connected to the lower mounting bracket. The ends of the first flow-blocking part and the second flow-blocking part are connected to each other, and the connected first flow-blocking part and the second flow-blocking part are supported between the upper mounting bracket and the lower mounting bracket.

[0031] Furthermore, a bonding portion is provided on one side of the first flow-blocking portion and the second flow-blocking portion. The bonding portion is located between two adjacent battery cells and is bonded to the surface of the battery cells. The bonding portion is adapted to seal the gap between the two adjacent battery cells.

[0032] Furthermore, the ratio of the projected area of ​​the air intake area to the projected area of ​​the first surface on the housing is 1.5%-10%.

[0033] Furthermore, the ratio of the projected area of ​​the air outlet area to the projected area of ​​the second surface on the housing is 2%-8%.

[0034] Furthermore, the ratio of the air outlet area to the air inlet area is less than 95%.

[0035] Furthermore, there are two air inlets, located on opposite sides of the battery cell assembly.

[0036] Furthermore, a control component is located in the rear end area of ​​the battery cell assembly within the housing.

[0037] The advantages of the battery pack provided in this application compared to the prior art are as follows: The housing of this application is provided with an isolation component, which is located on one side of the air intake area. The isolation component can guide the flow path of the cooling air entering the housing, so that the cooling air passes through the front area of ​​the cell assembly and then detours to the rear area, and then is discharged from the air outlet (the air outlet is close to the rear area of ​​the cell assembly). The flowing cooling air can fully contact each cell unit in the front and rear areas, thereby improving the cooling effect of the cell assembly. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the battery pack structure in one embodiment of this application.

[0040] Figure 2 This is a schematic diagram of the internal structure of the battery pack in one embodiment of this application.

[0041] Figure 3 This is a top view of a battery pack in one embodiment of this application.

[0042] Figure 4 This is a side view of the battery pack in one embodiment of this application.

[0043] Figure 5 for Figure 3 A schematic diagram of the cross section along line AA.

[0044] Figure 6 for Figure 4 A schematic diagram of the cross section along line BB.

[0045] Figure 7 This is a schematic diagram illustrating the airflow effect of the cooling air inside the battery pack of this application.

[0046] Figure 8 This is a schematic diagram illustrating the airflow effect between the front and rear regions of the battery pack in this application.

[0047] Figure 9 This is a schematic diagram showing the arrangement of the internal cell components of the battery pack in this application.

[0048] Figure 10 for Figure 9 A schematic diagram of the assembly of the upper and lower mounting brackets relative to the battery cell assembly.

[0049] Figure 11 for Figure 8 Enlarged view of area C in the image.

[0050] Figure 12 This is a schematic diagram of the assembly of the upper and lower mounting brackets of this application.

[0051] Figure 13 This is a schematic diagram showing the placement of the battery pack on the charger according to this application.

[0052] Figure 14This is a schematic diagram of the internal structure of the charger in this application. Detailed Implementation

[0053] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0054] Reference Figure 1 , Figure 2 , Figure 9 A battery pack 100 has an internal cooling structure. The battery pack 100 includes a housing 10, an upper mounting bracket 20 and a lower mounting bracket 30 spaced apart within the housing 10, and a cell assembly 40 disposed between the upper mounting bracket 20 and the lower mounting bracket 30.

[0055] The housing 10 has a first surface 101 and a second surface 102. The first surface 101 is the side surface of the housing 10, and the second surface 102 is the top surface of the housing 10. The first surface 101 has an air inlet area 103, and the second surface 102 has an air outlet area 104. The first surface 101 has multiple air inlets 105 located in the air inlet area 103, and the second surface 102 has multiple air outlets 106 located in the air outlet area 104. The first surface 101 and the second surface 102 are staggered. In this embodiment, the first surface 101 and the second surface 102 are staggered and perpendicular to each other. Correspondingly, the air inlet area 103 and the air outlet area 104 are staggered and perpendicular to each other on the surface of the housing 10.

[0056] In some embodiments, the ratio of the projected area of ​​the air inlet region 103 to the projected area of ​​the first surface 101 on the housing 10 is 1.5%-10%; the ratio of the projected area of ​​the air outlet region 104 to the projected area of ​​the second surface 102 on the housing 10 is 2%-8%; and the ratio of the air outlet area of ​​the air outlet region to the air inlet area of ​​the air inlet region is less than 95%, preferably 50%-85%.

[0057] Reference Figures 3 to 9 The housing 10 is provided with an isolation element 50, which is located on one side of the air inlet area 103. The air inlet area 103, the isolation element 50 and the air outlet area 104 form a heat dissipation channel.

[0058] Furthermore, in terms of specific structure, the battery cell assembly 40 includes several battery cell units 40a. The two ends of the battery cell unit 40a are respectively connected to the upper mounting bracket 20 and the lower mounting bracket 30. Each battery cell unit 40a is arranged side by side in the housing 10 with alternating positive and negative terminals.

[0059] From the perspective of overall structure, the battery cell assembly 40 includes a first side portion 401, a second side portion 402, a third side portion 403, a middle portion 404, and a top portion 405. The plane where the top portion 405 is located is perpendicular to the plane where the first side portion 401 is located.

[0060] The air inlet area 103 is close to the first side surface 401, and the air outlet area 104 is close to the third side surface 403 and located above the top 405.

[0061] The heat dissipation channel passes through the first side portion 401, the second side portion 402, the middle portion 404 and the third side portion 403 in sequence, and the two ends of the heat dissipation channel are the air inlet cavity 60 and the air outlet cavity 70, respectively.

[0062] After the battery cell assembly 40 is installed inside the housing 10, the first side portion 401, the isolation member 50 and the inner wall of the housing 10 form an air inlet cavity 60, and the third side portion 403, the isolation member 50 and the inner wall of the housing 10 form an air outlet cavity 70. The air inlet cavity 60 and the air outlet cavity 70 are separated by the isolation member 50. The air inlet cavity 60 is connected to the air inlet 105, and the air outlet cavity 70 is connected to the air outlet 106.

[0063] Cooling air flowing in through air inlet 105 enters air inlet cavity 60, passes over first side portion 401, enters second side portion 402 and middle portion 404, and flows out from third side portion 403. The outflowing cooling air enters air outlet cavity 70 and is discharged from air outlet 106. After the cooling air enters the battery pack from air inlet area 103, it can relatively increase the flow time of cooling air in the battery pack, extend the flow path, enhance the cooling effect, and prevent cooling air from flowing out of the air outlet area quickly.

[0064] Furthermore, in order to prevent the cooling air entering the air inlet cavity 60 from flowing directly into the direction of the third side portion 403, a flow-blocking member 80 is provided between two adjacent battery cell units 40a at the first side portion 401. The flow-blocking member 80 can block the gap between the two adjacent battery cell units 40a. The flow-blocking member 80 is located inside the air inlet cavity 60 and is provided on one side of the isolation member 50.

[0065] Furthermore, in this embodiment, the battery cell assembly 40 has two first side faces 401, and correspondingly, there are two air inlet chambers 60. The two air inlet chambers 60 are located on both sides of the battery cell assembly 40, and the line connecting the flow-blocking elements 80 on the two first side faces 401 divides the battery cell assembly 40 into a front end region 40b and a rear end region 40c.

[0066] A portion of the middle portion 404 and the second side portion 402 are located within the front end region 40b, and a portion of the middle portion 404 and the third side portion 403 are located within the rear end region 40c.

[0067] After the cooling air flows into the air inlet 105 on both sides of the housing 10 and enters the air inlet cavity 60, the cooling air flows from both sides of the cell assembly 40 to the front end region 40b, then detours from the front end region 40b to the rear end region 40c, and finally enters the air outlet cavity 70 and is discharged from the air outlet 106. After the cooling air enters the battery pack from the air inlet region 103, it can relatively increase the flow time of the cooling air in the battery pack, extend the flow path, enhance the cooling effect, and prevent the cooling air from flowing out directly from the air outlet region 104 quickly.

[0068] From the positional design of the air inlet area 103 and the air outlet area 104, taking the common edge of the first surface 101 and the second surface 102 as the baseline, the projection of the air inlet area 103 on the baseline is the first projection with a length of L1, and the projection of the air outlet area 104 on the baseline is the second projection with a length of L2. The overlap length of the first projection and the second projection is L12, where L12 < L1 and L12 < L2. Since the projections of the air inlet area 103 and the air outlet area 104 on the baseline only partially overlap (L12 < L1 and L12 < L2), this design can guide the cooling air to form a specific flow path when entering the interior of the battery pack 100. This can prevent the cooling air entering the air inlet area 103 from directly flowing to the air outlet area 104 in a short-circuit manner, allowing the cooling air to stay inside the battery pack for a longer time and improving the heat dissipation effect.

[0069] Furthermore, the partially overlapping projection design helps control the flow direction of cooling air inside the battery pack. If the air inlet area 103 and the air outlet area 104 overlap significantly, it can easily lead to air backflow and turbulence. In this application, by limiting the overlap length L12, cooling air can enter the battery pack 100 in a relatively orderly manner and then flow to the air outlet area 104 according to the designed heat dissipation channel. This reduces disordered collisions and backflow of cooling air inside the battery pack 100, which has a positive effect on reducing internal noise (because turbulence generates significant noise) within the battery pack 100.

[0070] The present application will now be described in detail with reference to the structure of the isolation element 50 and the flow-blocking element 80.

[0071] Specifically, refer to Figures 9 to 12 The isolation member 50 includes a first isolation part 501 connected to the upper mounting bracket 20 and a second isolation part 502 connected to the lower mounting bracket 30, with the ends of the first isolation part 501 and the second isolation part 502 mating together.

[0072] After docking, the first isolation part 501 and the second isolation part 502 are locked together by the fastener 503 and supported between the upper mounting bracket 20 and the lower mounting bracket 30. The fastener 503 is preferably a screw.

[0073] Furthermore, a bonding portion 504 is provided on one side of the first isolation portion 501 and the second isolation portion 502. The cross-section of the bonding portion 504 is trapezoidal. The bonding portion 504 is located between two adjacent battery cell units 40a and is bonded to the surface of the battery cell unit 40a. The bonding portion 504 can seal the gap between the two adjacent battery cell units 40a.

[0074] On the other side of the first isolation part 501 and the second isolation part 502, there is a locking part 505. The locking part 505 engages with the protruding rib 10a on the inner wall of the housing 10. The isolation member 50 mainly plays the role of isolation and support between the first side part 401 and the inner wall of the housing 10. After the isolation member 50 is set, the cooling air in the air inlet cavity 60 can be prevented from flowing directly towards the rear end region 40c of the cell assembly 40. The cooling air will first flow to the front end region 40b and contact each cell unit 40a in the front end region 40b, then detour to the rear end region 40c, then contact each cell unit 40a in the rear end region 40c, and finally flow into the air outlet cavity 70 and be discharged from the air outlet 106.

[0075] In addition, since the upper mounting bracket 20 and the lower mounting bracket 30 are spaced apart from each other, after the isolation member 50 is installed, the first isolation part 501 and the second isolation part 502 can play a supporting role between the upper mounting bracket 20 and the lower mounting bracket 30, ensuring the stability of the installation of the upper mounting bracket 20 and the lower mounting bracket 30.

[0076] Furthermore, the flow obstruction member 80 includes a first flow obstruction part 801 connected to the upper mounting bracket 20 and a second flow obstruction part 802 connected to the lower mounting bracket 30. The ends of the first flow obstruction part 801 and the second flow obstruction part 802 are connected to each other, and the connected first flow obstruction part 801 and the second flow obstruction part 802 are supported between the upper mounting bracket 20 and the lower mounting bracket 30.

[0077] A fitting portion 803 is provided on one side of the first flow-blocking part 801 and the second flow-blocking part 802. The fitting portion 803 is located between two adjacent battery cell units 40a and fits against the surface of the battery cell unit 40a. The cross-section of the fitting portion 803 is trapezoidal. Similarly, the fitting portion 803 can seal the gap between two adjacent battery cell units 40a. After the flow-blocking component 80 is installed, its main function is still to seal the gap between adjacent battery cell units 40a on the side of the first side part 401 near the air outlet cavity 70. Therefore, the flow-blocking component 80 is generally installed next to the isolation component 50. Multiple flow-blocking components 80 can be installed on the side of the first side part 401, so that the cooling air in the air inlet cavity 60 does not flow directly to the rear end region 40c of the battery cell assembly 40, but first flows to the front end region 40b of the battery cell assembly 40, and then detours to the rear end region 40c. This allows the flowing cooling air to fully contact each battery cell 40a in the battery cell assembly 40, achieving a better cooling effect.

[0078] Furthermore, a control component 200 is provided inside the housing 10 at the rear end of the cell assembly 40. The control component 200 is also located at the top 405 of the cell assembly 40. There is a gap between the housing 10 and the cell assembly 40. Under the suction action of the fan outside the air outlet area 104, the heat inside the control component 200 enters the cell assembly 40 through the gap, and then flows out from the air outlet area 104 together with the cooling air through airflow.

[0079] The following section describes the actual heat dissipation process of the battery pack 100 in the context of its charging application.

[0080] Reference Figure 13 , Figure 14The charger 300 for charging the battery pack 100 includes a charger body 310 with multiple charging positions 320. A fan 330 is installed within each charging position 320. The charger body 310 has an exhaust port 340 corresponding to the exhaust end of the fan 330. When the battery pack 100 is charged on the charger 300, the battery pack 100 is inserted into the charging position 320. A gap 350 is left between the side of the battery pack 100 and the inner wall of the charging position 320. This gap 350 is close to the air inlet area 103 of the battery pack 100. After the battery pack 100 is installed in the charging position 320, the exhaust port 340 of the battery pack 100... The airflow area 104 is close to the air inlet of the fan 330. During the charging process of the battery pack 100, the fan 330 at the corresponding charging position 320 is activated. The fan 330 causes airflow, thereby forming suction. The suction causes the outside cooling air to flow into the charging position 320 through the gap 350 and enter the housing of the battery pack 100 through the air inlet area 103. The cooling air passes through the front end area 40b of the cell assembly 40, then detours to the rear end area 40c, and finally flows out from the air outlet area 104. The hot airflow is drawn in by the fan 300 and discharged from the exhaust port 340 on the charger body 310.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A battery pack, characterized by, The application relates to a battery pack. The battery pack comprises a shell, an upper mounting rack and a lower mounting rack which are arranged in the shell, an electric cell assembly which is arranged in the shell and between the upper mounting rack and the lower mounting rack, an air inlet area and an air outlet area which are arranged on the shell, a partition which is arranged in the shell, and a heat dissipation channel which is formed by the air inlet area, the partition and the air outlet area. The partition comprises a first partition part which is connected with the upper mounting rack and a second partition part which is connected with the lower mounting rack, and the end of the first partition part and the end of the second partition part are connected with each other. The first partition part and the second partition part are locked by a fixing part and are supported between the upper mounting rack and the lower mounting rack. One side of the first partition part and the second partition part is provided with a fitting part which is arranged between two adjacent electric cell units and is fitted with the surface of the electric cell units, and the fitting part is suitable for sealing the gap between the two adjacent electric cell units. The other side of the first partition part and the second partition part is provided with a clamping part which is clamped with a convex rib on the inner wall of the shell. The shell is provided with adjacent first and second surfaces which are staggered with each other, the air inlet area is arranged on the first surface, and the air outlet area is arranged on the second surface. The projection of the air inlet area on the reference line is a first projection with a length of L1, the projection of the air outlet area on the reference line is a second projection with a length of L2, and the overlapping length of the first projection and the second projection is L12, wherein L12 < L1 and L12 < L2. The air inlet area is provided with a plurality of air inlets, and the air outlet area is provided with a plurality of air outlets. The electric cell assembly comprises a first side part, a second side part, a third side part, a middle part and a top part.

2. The battery pack of claim 1, wherein, The air inlet area is close to the first side part, the air outlet area is close to the third side part and is arranged above the top part. The heat dissipation channel sequentially passes through the first side part, the second side part, the middle part and the third side part, and the two ends of the heat dissipation channel are an air inlet cavity and an air outlet cavity.

3. The battery pack of claim 2, wherein, The first side part, the partition and the inner wall of the shell form the air inlet cavity, the third side part, the partition and the inner wall of the shell form the air outlet cavity, the air inlet cavity and the air outlet cavity are separated by the partition, the air inlet cavity is communicated with the air inlets, and the air outlet cavity is communicated with the air outlets.

4. The battery pack of claim 3, wherein, The cooling air which flows into the air inlets enters the air inlet cavity, sweeps through the first side part, enters the second side part and the middle part, and flows out from the third side part, and the flowing-out cooling air enters the air outlet cavity and is guided out from the air outlets. The plane where the top part is located is perpendicular to the plane where the first side part is located. The electric cell assembly comprises a plurality of electric cell units, and the two ends of the electric cell units are connected with the upper mounting rack and the lower mounting rack respectively. ​ ​ 5. The battery pack of claim 4, wherein, ​ 6. The battery pack of claim 4, wherein, ​ 7. The battery pack of claim 6, wherein, The two adjacent battery cell units at the first side part are provided with a blocking piece adapted to block the gap between the two adjacent battery cell units, and the blocking piece is located in the air inlet cavity and arranged on one side of the isolation piece.

8. The battery pack of claim 7, wherein, The battery cell assembly is provided with two first side parts, and the line between the blocking pieces on the two first side parts divides the battery cell assembly into a front end region and a rear end region. Part of the middle part and the second side part are located in the front end region, and part of the middle part and the third side part are located in the rear end region. After the cooling air flowing into the air inlet cavity from the air inlet, the cooling air flows to the front end region from both sides of the battery cell assembly, then meanders from the front end region to the rear end region, and finally enters the air outlet cavity and is discharged from the air outlet.

9. The battery pack of claim 7, wherein, The blocking piece comprises a first blocking part connected with the upper mounting frame and a second blocking part connected with the lower mounting frame, and the end of the first blocking part and the second blocking part are butted against each other, and the butted first blocking part and second blocking part are supported between the upper mounting frame and the lower mounting frame.

10. The battery pack of claim 9, wherein, One side of the first blocking part and the second blocking part is provided with a fitting part located between the two adjacent battery cell units and fitted with the surface of the battery cell unit, and the fitting part is adapted to seal the gap between the two adjacent battery cell units.

11. The battery pack of claim 2, wherein, The ratio of the projection area of the air inlet region to the projection area of the first surface on the shell is 1.5%-10%.

12. The battery pack of claim 2, wherein, The ratio of the projection area of the air outlet region to the projection area of the second surface on the shell is 2%-8%.

13. The battery pack of claim 2, wherein, The ratio of the air outlet area of the air outlet region to the air inlet area of the air inlet region is less than 95%.

14. The battery pack of claim 4, wherein, The number of air inlet cavities is two, and the two air inlet cavities are located on both sides of the battery cell assembly.

15. The battery pack of claim 8, wherein, The control assembly is arranged in the rear end region of the battery cell assembly in the shell.

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