Battery pack

Abstract

The application provides a battery pack, comprising a battery cell assembly, a busbar assembly and an insulation layer, the battery cell assembly comprises a plurality of battery cells, the battery cell comprises a first end and a second end distributed along the height direction of the battery pack, the first end is provided with a pressure relief hole; the busbar assembly comprises a busbar and a support for mounting the busbar, the support is arranged on the first end, the busbar is connected with the first end, and the support is provided with a through hole corresponding to the position of at least one pressure relief hole; the insulation layer is arranged on the side of the busbar assembly away from the battery cell assembly, the insulation layer comprises a first covering part covering at least part of the busbar assembly and a second covering part covering at least part of the through hole, and a gap is formed between the second covering part and the first covering part. When at least one pressure relief hole of the battery cell is relieved, the second covering part is more easily broken by the gas, electrolyte and the like entering the through hole of the support, so that the pressure relief hole of the battery cell is not easily hindered by the insulation layer, and the pressure relief hole can be relieved more smoothly.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery pack. Background Technology

[0002] In related technologies, a pressure relief hole can be provided at the end of the battery cell that is connected to the busbar. When the gas pressure inside the cell exceeds the preset gas pressure, the pressure relief valve located at the pressure relief hole will open so that the gas inside the cell can be discharged through the pressure relief hole into the pressure relief channel of the battery pack.

[0003] To prevent electrolyte or conductive particles draining from the battery cell from contacting the busbar and causing a short circuit, and to prevent foreign objects from entering and clogging the pressure relief hole, an insulating layer can be installed on the side of the busbar away from the battery cell to cover the busbar and the pressure relief hole. However, after the insulating layer covers the pressure relief hole, the pressure relief hole may be obstructed by the insulating layer during pressure relief, resulting in the pressure relief hole not being able to release pressure smoothly. Utility Model Content

[0004] The embodiments of this application provide a battery pack that can improve the technical problem that the pressure relief hole of the battery cell may be blocked by the insulating layer when it is depressurizing, resulting in the pressure relief hole being unable to depressurize smoothly.

[0005] In a first aspect, embodiments of this application provide a battery pack, comprising:

[0006] A battery cell assembly includes multiple battery cells, each battery cell having a first end and a second end distributed along the height direction of the battery pack, the first end having a pressure relief hole;

[0007] A busbar assembly includes a busbar and a bracket for mounting the busbar, the bracket being disposed at the first end, the busbar being connected to the battery cell, and the bracket having a through hole corresponding to at least one of the pressure relief holes;

[0008] An insulating layer is disposed on the side of the busbar assembly opposite to the cell assembly. The insulating layer includes a first cover portion covering at least a portion of the busbar assembly and a second cover portion covering at least a portion of the through-hole. A gap is formed between the second cover portion and the first cover portion.

[0009] In some embodiments, the first cover portion has an opening corresponding to the position of the through hole, and the second cover portion is located within the opening. Thus, by cutting the insulating layer, a first cover portion with an opening and a second cover portion located within the opening can be formed in the insulating layer, making processing very convenient. Furthermore, a longer gap can be formed between the edge of the opening of the first cover portion and the edge of the second cover portion, which facilitates the opening of the through hole by the second cover portion under the impact of gas or electrolyte passing through the through hole of the support, allowing the gas or electrolyte within the through hole to be quickly discharged.

[0010] In some embodiments, the insulating layer further includes a connecting portion that connects the edge of the second cover portion and the edge of the opening, thereby keeping the second cover portion connected to the first cover portion through the connecting portion, so that the second cover portion is stably held in the opening.

[0011] In some embodiments, the through-hole is an arc-shaped hole extending circumferentially along the central axis of the corresponding battery cell, thereby reducing the assembly precision requirements of the battery cell and the bracket, which helps to reduce the production cost of the battery pack and improve the production efficiency of the battery pack. The extension direction of the second cover is consistent with the extension direction of the through-hole. Therefore, the shape of the second cover can be more adapted to the shape of the through-hole, allowing the second cover to cover the through-hole as much as possible while maximizing the area of ​​the first cover to increase the coverage area of ​​the first cover on the busbar assembly.

[0012] In some embodiments, the connecting portion is located on the side of the second cover portion near the central axis of the corresponding battery cell. When the second cover portion is impacted by gas or electrolyte in the through hole, the connecting portion has a weaker restraint on the second cover portion, and the second cover portion can quickly open the through hole to allow the gas or electrolyte in the through hole to be discharged.

[0013] In some embodiments, on a projection plane perpendicular to the height direction, the second cover portion orthographically covers the orthographic projection of the through hole. This allows the second cover portion to completely cover the through hole, thereby further reducing the risk of foreign objects entering the pressure relief hole through the through hole and clogging it.

[0014] In some embodiments, the first cover is bonded to the side of the busbar assembly away from the cell assembly, thereby improving the connection stability between the first cover and the busbar assembly, and thus improving the insulation and isolation effect of the first cover on the busbar assembly; and / or, the second cover is bonded to the side of the busbar assembly away from the cell assembly, thereby improving the connection stability between the second cover and the busbar assembly, and thus improving the coverage stability of the second cover on the through hole.

[0015] In some embodiments, the bracket has a protrusion on the side opposite to the cell assembly, and the through hole penetrates the protrusion along the height direction;

[0016] The first cover is bonded to the surface of the protrusion facing away from the battery cell assembly, thereby giving the first cover a high bonding strength with the edge of the through hole. When gas, electrolyte, or metal particles ejected from the through hole are discharged to the side of the insulating layer facing away from the busbar assembly, the first cover and the edge of the through hole remain sealed. This prevents electrolyte, metal particles, or other conductive materials from entering the gap between the edge of the through hole and the first cover and coming into contact with the busbar or battery cell of the busbar assembly, thus avoiding secondary short circuits. And / or, the second cover is bonded to the surface of the protrusion facing away from the battery cell assembly, thereby giving the second cover a high bonding strength with the edge of the through hole, making the second cover less prone to collapse and providing a more stable cover over the through hole.

[0017] In some embodiments, on a projection plane perpendicular to the height direction, the orthographic projection of the edge of the first covering portion near the second covering portion lies within the orthographic projection of the protrusion, enabling the edge of the first covering portion to approach the through hole and adhere to the protrusion, thereby improving the sealing stability of the first covering portion and the edge of the through hole; and / or,

[0018] On a projection plane perpendicular to the height direction, the orthographic projection of the edge of the second cover portion lies within the orthographic projection of the protrusion. This allows the edge of the second cover portion to adhere to the surface of the protrusion facing away from the battery cell assembly, thereby improving the adhesion stability between the second cover portion and the protrusion.

[0019] In some embodiments, the bracket has through holes corresponding to the pressure relief holes of the plurality of battery cells; the insulating layer includes a plurality of second covering portions, the number of which is equal to the number of through holes, and they are arranged in a one-to-one correspondence. Thus, the multiple through holes can be covered by the multiple second covering portions, reducing the risk of foreign objects entering the pressure relief holes through the through holes and causing blockage.

[0020] In some embodiments, the battery pack further includes expanding foam filling the gaps between the battery cells. A first end face of each battery cell has a protruding terminal post for connection to the busbar. The first end of the battery cell protrudes beyond the side of the expanding foam. The height of the first end face of the battery cell relative to the side of the expanding foam is greater than or equal to 5 mm and less than or equal to 10 mm. This allows the expanding foam to stably position the battery cells without affecting the installation of the busbar assembly.

[0021] The beneficial effects of the embodiments of this application are as follows:

[0022] The battery pack provided in this application embodiment has pressure relief holes at the first ends of multiple battery cells in the cell assembly, and a busbar bracket is disposed at the first end of the battery cells, so that the busbar mounted on the bracket is connected to the battery cells, thereby connecting multiple battery cells in series or parallel. At the same time, by opening through holes at the positions of at least one pressure relief hole on the bracket, when pressure is released from at least one pressure relief hole of the battery cell, the gas, electrolyte, etc. discharged from the pressure relief hole of the battery cell can be discharged through the through holes of the bracket without being obstructed by the bracket.

[0023] Based on this, by placing the insulating layer on the side of the busbar assembly away from the battery cell assembly, the insulating layer includes a first cover portion covering at least a portion of the busbar assembly and a second cover portion covering at least a portion of the through-hole, with a gap formed between the second cover portion and the first cover portion. When at least one pressure relief hole of the battery cell is depressurized, the second cover portion is more easily opened by gas, electrolyte, etc. entering the through-hole of the support, and the pressure relief hole of the battery cell is less likely to be obstructed by the insulating layer when depressurizing, allowing the pressure relief hole to depressurize more smoothly.

[0024] Meanwhile, the first cover is not easily interfered with by the second cover and can stably cover at least part of the busbar assembly, so that the gas, electrolyte, etc. discharged to the side of the insulation layer away from the busbar assembly are kept insulated from at least part of the busbar, which is beneficial to improving the safety of the battery pack. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of one embodiment of the battery pack provided in this application.

[0027] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0028] Figure 3 for Figure 1 A cross-sectional view along the AA direction;

[0029] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0030] Figure 5 for Figure 3 Enlarged view of point C in the middle;

[0031] Figure 6A top view of one embodiment of the battery cell assembly, support assembly, and foam provided in this application;

[0032] Figure 7 for Figure 6 Enlarged view of point D in the middle.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1-Battery pack; 10-Cell assembly; 11-Cell; 110-First end; 111-End face; 112-Terminal post; 113-Relief hole; 114-Relief valve; 115-Second end; 20-Busseter assembly; 21-Busseter; 211-Connector; 212-Output row; 22-Bracket; 221-Through hole; 222-Protrusion; 40-Insulating layer; 41-First cover; 411-Opening; 42-Second cover; 421-Gap; 43-Connection; 50-Foam; 60-Temperature regulating plate; S-Arc segment; α-Included angle; H-Height; X-Central axis; Z-Height direction. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0036] This application provides a battery pack. The following provides detailed descriptions of various embodiments of the battery pack.

[0037] Figure 1 This is a schematic diagram of the structure of one embodiment of the battery pack provided in this application. Figure 2 for Figure 1 Enlarged view of point A in the middle. Figure 3 for Figure 1 A cross-sectional view along the AA direction. (See example...) Figures 1 to 3As shown, the battery pack 1 includes a cell assembly 10, which includes multiple cells 11. Each cell 11 has a first end 110 and a second end 115 distributed along the height direction Z of the battery pack 1. The first end 110 of the cell 11 is provided with a pressure relief hole 113. When the air pressure inside the cell 11 exceeds a preset air pressure, the pressure relief hole 113 will be opened to allow the gas inside the cell 11 to be discharged through the pressure relief hole 113, thereby achieving rapid pressure relief of the cell 11. A pressure relief valve 114 can be provided at the pressure relief hole 113, covering the pressure relief hole 113. When the air pressure inside the cell 11 exceeds the preset air pressure, the pressure relief valve 114 opens, thereby opening the pressure relief hole 113.

[0038] Alternatively, a thinning groove can be directly provided on the cover plate at the first end 110 of the battery cell 11 to form a closed pressure relief hole 113. When the gas pressure inside the battery cell 11 exceeds the preset gas pressure, the high-pressure gas will cause the cover plate to break at the thinning groove, thereby opening the pressure relief hole 113.

[0039] Continue to refer to Figure 1 and Figure 2 The battery pack 1 also includes a busbar assembly 20, which includes a busbar 21 connected to the battery cells 11. By connecting the busbar 21 of the busbar assembly 20 to multiple battery cells 11, the multiple battery cells 11 can be connected in series or in parallel through the busbar 21.

[0040] Busbar 21 can be connected to the first end 110 of battery cell 11 or to other parts of battery cell 11. Battery cell 11 may include a terminal post 112 protruding from the end face 111 of the first end 110. The terminal post 112 is insulated from the end face 111 of the first end 110 of battery cell 11, and the polarity of the terminal post 112 is opposite to the polarity of the end face 111 of the first end 110 of battery cell 11. The terminal post 112 can be the positive terminal and the end face 111 of the first end 110 of battery cell 11 can be the negative terminal, or vice versa.

[0041] Figure 6 This is a top view of one embodiment of the battery cell assembly, support assembly, and foam provided in this application. Figure 7 for Figure 6 A magnified view of point C in the middle. (See image below.) Figure 6 and Figure 7As shown, the busbar 21 includes multiple connectors 211. The terminal 112 of one of the two battery cells 11 is connected to the end face 111 of the first end 110 of the other battery cell 11 through the connector 211, thereby connecting the two battery cells 11 in series. Of course, the terminals 112 of the two battery cells 11 can also be connected through the connector 211 to connect the two battery cells 11 in parallel; or, the end faces 111 of the first ends 110 of the two battery cells 11 can be connected through the connector 211 to connect the two battery cells 11 in parallel.

[0042] Specifically, the battery cell assembly 10 includes multiple rows of battery cells 11. In the same row of battery cells 11, the terminal 112 of one of two adjacent battery cells 11 is connected to the end face 111 of the first end 110 of the other battery cell 11 via a connector 211, so that the battery cells 11 in the same row are connected in series. The connector 211 connected to different rows of battery cells 11 can be connected via an output bar 212, so that multiple battery cells 11 are connected in parallel.

[0043] Figure 4 for Figure 3 A magnified view of point B in the middle. (See image below.) Figure 3 and Figure 4 As shown, the busbar assembly 20 of the battery pack 1 may further include a bracket 22 for mounting the busbar 21. The bracket 22 is disposed at the first end 110 of the cell 11 so that the bracket 22 can position the cell 11 and facilitate the connection of the busbar 21 to the first end 110 of the cell 11. The busbar 21 is located on the side of the bracket 22 away from the cell assembly 10, and the busbar 21 passes through the bracket 22 and connects to the terminal post 112 of the cell 11 or the end face 111 of the first end 110 of the cell 11.

[0044] In some embodiments, a through hole 221 may be provided on the bracket 22 at a position corresponding to the pressure relief hole 113 of at least one cell 11, so that when the pressure relief hole 113 of the cell 11 is depressurized, the gas, electrolyte and the like discharged from the pressure relief hole 113 of the cell 11 can be discharged through the through hole 221 of the bracket 22 without being obstructed by the bracket 22.

[0045] It should be noted that the through hole 221 and the pressure relief hole 113 are positioned correspondingly. Specifically, on a projection plane perpendicular to the height direction Z, the orthographic projection of the through hole 221 and the orthographic projection of the corresponding pressure relief hole 113 at least partially overlap. Therefore, when the pressure relief hole 113 of the battery cell 11 is opened, the gas, electrolyte, etc. inside the battery cell 11 can quickly pass through the through hole 221 and be discharged to the side of the support 22 away from the battery cell 11, and the pressure relief of the battery cell 11 will not be blocked by the support 22.

[0046] Alternatively, the bracket 22 can have a through hole 221 corresponding to the pressure relief hole 113 of one battery cell 11, or the bracket 22 can have through holes 221 corresponding to the pressure relief holes 113 of multiple battery cells 11. Of course, the latter allows more battery cells 11 to be depressurized through the through holes 221 of the bracket 22, resulting in higher safety for the battery pack 1.

[0047] In some embodiments, on a projection plane perpendicular to the height direction Z of the battery pack 1, the orthographic projection of the through hole 221 of the bracket 22 can cover the orthographic projection of the pressure relief hole 113 of the corresponding cell 11. Therefore, the edge of the through hole 221 will not obstruct the gas, electrolyte, etc. discharged from the corresponding pressure relief hole 113, allowing the gas, electrolyte, etc. discharged from the pressure relief hole 113 to pass more smoothly through the through hole 221 of the bracket 22, which is beneficial to improving the safety and pressure relief efficiency of the battery pack 1.

[0048] Specifically, the orthographic projection of the through hole 221 of the bracket 22 onto the projection plane perpendicular to the height direction Z of the battery pack 1 can be made to coincide with the orthographic projection of the pressure relief hole 113 of the corresponding cell 11 onto the projection plane perpendicular to the height direction Z of the battery pack 1. Alternatively, the orthographic projection area of ​​the through hole 221 of the bracket 22 onto the projection plane perpendicular to the height direction Z of the battery pack 1 can be larger than the orthographic projection area of ​​the pressure relief hole 113 of the corresponding cell 11 onto the projection plane perpendicular to the height direction Z of the battery pack 1. Of course, the latter can further reduce the obstruction caused by the edge of the through hole 221 to the gas, electrolyte, etc. discharged from the corresponding pressure relief hole 113, which is conducive to smoother pressure relief of the cell 11.

[0049] In some embodiments, such as Figure 1 , Figure 2 and Figure 4 As shown, the battery pack 1 may include an insulating layer 40, which is disposed on the side of the busbar assembly 20 away from the cell assembly 10. The insulating layer 40 includes a first cover portion 41 covering at least a portion of the busbar assembly 20 and a second cover portion 42 covering at least a portion of the through hole 221. A gap 421 is formed between the second cover portion 42 and the first cover portion 41.

[0050] The battery pack 1 provided in this application embodiment has pressure relief holes 113 at the first ends 110 of multiple battery cells 11 in the cell assembly 10, and the bracket 22 of the busbar assembly 20 is disposed at the first ends 110 of the battery cells 11, so that the busbar 21 installed on the bracket 22 is connected to the first ends 110 of the battery cells 11, thereby connecting multiple battery cells 11 in series or in parallel. At the same time, by opening through holes 221 at the positions of at least one pressure relief hole 113 on the bracket 22, when pressure is released from at least one pressure relief hole 113 of the battery cell 11, the gas, electrolyte, etc. discharged from the pressure relief hole 113 of the battery cell 11 can be discharged through the through holes 221 of the bracket 22 without being obstructed by the bracket 22.

[0051] Based on this, by placing the insulating layer 40 on the side of the busbar assembly 20 away from the cell assembly 10, the insulating layer 40 includes a first cover portion 41 covering at least a portion of the busbar assembly 20 and a second cover portion 42 covering at least a portion of the through hole 221, and a gap 421 is formed between the second cover portion 42 and the first cover portion 41. When at least one pressure relief hole 113 of the cell 11 is depressurized, the second cover portion 42 is more easily opened by gas, electrolyte, etc. entering the through hole 221 of the support 22, and the pressure relief hole 113 of the cell 11 is less likely to be obstructed by the insulating layer 40 when depressurizing, so that the pressure relief hole 113 can depressurize more smoothly.

[0052] Meanwhile, the first cover 41 is not easily interfered with by the second cover 42, and can stably cover at least part of the busbar assembly 20, so that the gas, electrolyte and other substances discharged to the side of the insulating layer 40 away from the busbar assembly 20 are kept insulated from at least part of the busbar 21, which is beneficial to improving the safety of the battery pack 1.

[0053] It should be noted that the first covering part 41 and the second covering part 42 can be completely separated, or they can be partially separated and partially connected. Of course, the latter can make the relative position between the first covering part 41 and the second covering part 42 more stable, which is beneficial to improving the overall assembly efficiency of the insulating layer 40.

[0054] In some embodiments, the first cover 41 may have an opening 411 corresponding to the position of the through hole 221, and the second cover 42 may be located within the opening 411. Thus, by cutting the insulating layer 40, the first cover 41 with the opening 411 and the second cover 42 located within the opening 411 can be formed in the insulating layer 40, making processing very convenient. Furthermore, a longer gap 421 can be formed between the edge of the opening 411 of the first cover 41 and the edge of the second cover 42, which facilitates the second cover 42 opening the through hole 221 under the impact of gas or electrolyte passing through the through hole 221 of the support 22, allowing the gas or electrolyte within the through hole 221 to be quickly discharged.

[0055] The insulating layer 40 may also include a connecting portion 43, which connects the edge of the second covering portion 42 and the edge of the opening 411, so that the second covering portion 42 is kept connected to the first covering portion 41 through the connecting portion 43, so that the second covering portion 42 is stably kept in the opening 411.

[0056] Specifically, a cut can be made along the edge of the second covering portion 42 to form a gap 421 between the edge of the opening 411 of the first covering portion 41 and the edge of the second covering portion 42. Moreover, the length of the cut along the edge of the second covering portion 42 is less than the length of the edge of the second covering portion 42, thereby forming a connecting portion 43 in the uncut area between the second covering portion 42 and the first covering portion 41, so that a portion of the edge of the second covering portion 42 is connected to the edge of the opening 411 through the connecting portion 43.

[0057] Of course, the connecting part 43 can also be connected to the edge of the second covering part 42 and the edge of the opening 411 by means of bonding, welding or other methods.

[0058] In some embodiments, such as Figure 6 and Figure 7 As shown, the through hole 221 is an arc-shaped hole extending circumferentially along the central axis X of the corresponding cell 11, thereby reducing the assembly accuracy requirements of the cell 11 and the bracket 22, which is beneficial to reducing the production cost of the battery pack 1 and improving the production efficiency of the battery pack 1.

[0059] It is understandable that during the assembly process of the battery cells 11 and brackets 22 of the battery pack 1 by machine or by hand, the rotation angle of multiple cells 11 relative to the central axis X is different. Therefore, there may be a certain assembly error in the assembly angle of the cells 11 relative to the brackets 22.

[0060] By making the through hole 221 of the bracket 22 an arc-shaped hole extending circumferentially along the central axis X of the corresponding cell 11, even if there are certain assembly errors in the assembly process of the cell 11 and the bracket 22, the orthographic projection of the through hole 221 of the bracket 22 on the projection plane perpendicular to the height direction Z of the battery pack 1 can still cover the orthographic projection of the pressure relief hole 113 of the corresponding cell 11 on the projection plane perpendicular to the height direction Z of the battery pack 1. Alternatively, the orthographic projection of the through hole 221 of the bracket 22 on the projection plane perpendicular to the height direction Z of the battery pack 1 and the orthographic projection of the pressure relief hole 113 of the corresponding cell 11 on the projection plane perpendicular to the height direction Z of the battery pack 1 can have a large overlap area, so that the gas, electrolyte, etc. discharged from the pressure relief hole 113 can pass through the through hole 221 of the bracket 22 more smoothly and be discharged.

[0061] Therefore, the assembly precision requirements for the bracket 22 and the battery cell 11 are relatively low. There is no need to assemble the battery cell 11 and the bracket 22 with complex machines, or to manually calibrate the assembly angle of the battery cell 11. This helps to reduce the production cost of the battery pack 1 and improve the production efficiency of the battery pack 1.

[0062] The central axis X of the battery cell 11 extends along the height direction Z of the battery pack 1. Specifically, the central axis X of the battery cell 11 is parallel to the height direction Z of the battery pack 1.

[0063] It should be noted that the through hole 221 of the bracket 22 and the central axis X of the corresponding battery cell 11 mean that the orthographic projection of the through hole 221 and the orthographic projection of the pressure relief hole of the corresponding battery cell 11 overlap on the projection plane perpendicular to the height direction Z.

[0064] In some embodiments, the center of the arc-shaped through hole 221 can be located on the central axis X of the battery cell 11, so that when the battery cell 11 rotates relative to the bracket 22 around the central axis X, there will be no large misalignment between the through hole 221 of the bracket 22 and the pressure relief hole 113 of the battery cell 11 in the width direction of the through hole 221.

[0065] Specifically, the arc-shaped hole extends along the arc segment S. The center of the arc segment S is located on the central axis X of the battery cell 11. The angle of the arc-shaped hole is greater than or equal to 20° and less than or equal to 40°. This minimizes the assembly precision requirements for the battery cell 11 and the bracket 22, while preventing the arc-shaped hole from being too large and affecting the strength of the bracket 22. The angle of the arc-shaped hole can be 21°, 25°, 28°, 30°, 37°, etc.

[0066] Specifically, the arc-shaped hole extends along the arc segment S, reaching both ends of the arc segment S. The angle of the arc-shaped hole is the angle α formed by the center of the arc segment S and the lines connecting the two ends of the arc segment S, where 20°≤α≤40°.

[0067] In some embodiments, the extending direction of the second cover portion 42 may be aligned with the extending direction of the through hole 221. This allows the shape of the second cover portion 42 to better match the shape of the through hole 221, enabling the second cover portion 42 to cover the through hole 221 as much as possible while maximizing the area of ​​the first cover portion 41, thereby increasing the coverage area of ​​the first cover portion 41 over the busbar assembly 20.

[0068] It should be noted that the extending direction of the second covering portion 42 can be exactly the same as the extending direction of the through hole 221, or it can be similar to the extending direction of the through hole 221, as long as the shape of the second covering portion 42 is more compatible with the shape of the through hole 221. Specifically, the second covering portion 42 can extend along the arc segment S, and the second covering portion 42 extends beyond both ends of the arc segment S, so that the second covering portion 42 can completely cover the through hole 221.

[0069] Among them, such as Figure 4 As shown, the connecting part 43 can be positioned on the side of the second cover part 42 close to the central axis X of the corresponding cell 11. When the second cover part 42 is impacted by gas or electrolyte in the through hole 221, the connection part 43 has a weaker restriction on the second cover part 42, and the second cover part 42 can quickly open the through hole 221 to allow the gas or electrolyte in the through hole 221 to be discharged.

[0070] In other embodiments, the connecting portion 43 may be located on the side of the second cover portion 42 away from the central axis X of the corresponding cell 11. Alternatively, the connecting portion 43 may be located at one end of the second cover portion 42 along its own extending direction.

[0071] In some embodiments, on a projection plane perpendicular to the height direction Z, the second cover portion 42 orthogonally covers the orthogonal projection of the through hole 221. This allows the second cover portion 42 to completely cover the through hole 221, thereby further reducing the risk of foreign matter entering the pressure relief hole 113 through the through hole 221 and causing blockage of the pressure relief hole 113.

[0072] Specifically, on the projection plane perpendicular to the height direction Z, the orthographic projection of the second covering part 42 can overlap with the orthographic projection of the through hole 221, or the orthographic projection area of ​​the second covering part 42 can be larger than the orthographic projection area of ​​the through hole 221. Of course, the latter allows the second covering part 42 to more stably cover the through hole 221.

[0073] In some embodiments, the first cover 41 can be bonded to the side of the busbar assembly 20 away from the cell assembly 10, thereby improving the connection stability between the first cover 41 and the busbar assembly 20, and further improving the insulation and isolation effect of the first cover 41 on the busbar assembly 20.

[0074] The first cover 41 can be bonded to either the busbar 21 or the bracket 22, or it can be bonded to both the busbar 21 and the bracket 22 simultaneously. Alternatively, the first cover 41 can be bonded to the busbar assembly 20 using double-sided adhesive. Of course, adhesive can also be applied to either the surface of the first cover 41 facing the busbar assembly 20 or the surface of the busbar assembly 20 facing the first cover 41, allowing the first cover 41 and the busbar assembly 20 to be bonded together using adhesive.

[0075] In some embodiments, such as Figure 4 and Figure 7 As shown, a protrusion 222 can be provided on the side of the bracket 22 away from the cell assembly 10, and a through hole 221 penetrates the protrusion 222 along the height direction Z. The first cover 41 is bonded to the surface of the protrusion 222 away from the cell assembly 10, so that the edge of the first cover 41 and the through hole 221 has a high bonding strength. When the gas, electrolyte, and metal particles ejected from the through hole 221 are discharged to the side of the insulating layer 40 away from the busbar assembly 20, the edge of the first cover 41 and the through hole 221 remain sealed. This can prevent electrolyte, metal particles or other conductive materials from entering the gap between the edge of the through hole 221 and the first cover 41 and coming into contact with the busbar 21 or the cell 11 of the busbar assembly 20, thus preventing a secondary short circuit.

[0076] In this configuration, on a projection plane perpendicular to the height direction Z, the orthographic projection of the edge of the first covering portion 41 near the second covering portion 42 lies within the orthographic projection of the protrusion 222. This allows the edge of the first covering portion 41 to approach the through hole 221 and adhere to the protrusion 222, thereby improving the sealing stability between the edge of the first covering portion 41 and the edge of the through hole 221.

[0077] In some embodiments, the second cover 42 can be bonded to the side of the busbar assembly 20 away from the cell assembly 10, thereby improving the connection stability between the second cover 42 and the busbar assembly 20, and further improving the coverage stability of the second cover 42 over the through hole 221.

[0078] In this way, the second cover 42 can be bonded to the surface of the protrusion 222 on the side away from the cell assembly 10, so that the second cover 42 and the edge of the through hole 221 have a high bonding strength, making the second cover 42 less prone to collapse and able to cover the through hole 221 more stably.

[0079] In some embodiments, on a projection plane perpendicular to the height direction Z, the orthographic projection of the edge of the second cover 42 can be located within the orthographic projection of the protrusion 222. This allows the edges of the second cover 42 to adhere to the surface of the protrusion 222 on the side opposite to the cell assembly 10, thereby improving the adhesion stability between the second cover 42 and the protrusion 222.

[0080] In some embodiments, through holes 221 may be formed on the bracket 22 corresponding to the pressure relief holes 113 of the plurality of battery cells 11. Meanwhile, the insulating layer 40 includes a plurality of second covering portions 42, the number of which is equal to the number of through holes 221, and they are arranged in a one-to-one correspondence. Thus, the multiple through holes 221 can be covered by the multiple second covering portions 42, reducing the risk of foreign objects entering the pressure relief holes 113 through the through holes 221 and causing blockage.

[0081] In some embodiments, such as Figure 3 and Figure 5 As shown, the battery pack 1 also includes expanding foam 50 filling the gaps between the battery cells 11. The expanding foam 50 can fix the battery cells 11, making the position of the battery cells 11 more stable. A terminal post 112 connected to the busbar 21 protrudes from the end face 111 of the first end 110 of the battery cell 11, and the first end 110 of the battery cell 11 protrudes from the side of the expanding foam 50. The height H of the end face 111 of the first end 110 of the battery cell 11 relative to the side of the expanding foam 50 is greater than or equal to 5 mm and less than or equal to 10 mm. Therefore, the expanding foam can stably position the battery cells 11 without affecting the installation of the busbar assembly 20.

[0082] The height H of the end face 111 of the first end 110 of the battery cell 11 relative to the side of the foam 50 can be 6mm, 6.4mm, 6.9mm, 7.3mm, 8mm, 9mm, etc., depending on the structure of the battery pack 1, and is not limited here.

[0083] In some embodiments, the insulating layer 40 may comprise mica paper. Therefore, the insulating layer 40 has good insulation and high-temperature flammability, effectively providing insulation and isolation between the busbar 21 and the battery cell 11. The thickness of the insulating layer 40 can be 0.3 mm, 0.5 mm, etc., and is not limited here.

[0084] In some embodiments, such as Figure 3 As shown, a temperature regulating plate 60 can be provided on the side of the battery cell assembly 10 away from the busbar assembly 20. The temperature regulating plate 60 and the second end 115 of the battery cell 11 can be connected by thermally conductive adhesive or other thermally conductive materials so that heat can be quickly transferred between the temperature regulating plate 60 and the second end 115 of the battery cell 11, thereby achieving temperature regulation of the battery cell 11.

[0085] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery pack, characterized in that, include: A battery cell assembly includes multiple battery cells, each battery cell having a first end and a second end distributed along the height direction of the battery pack, the first end having a pressure relief hole; A busbar assembly includes a busbar and a bracket for mounting the busbar, the bracket being disposed at the first end, the busbar being connected to the battery cell, and the bracket having a through hole corresponding to at least one of the pressure relief holes; An insulating layer is disposed on the side of the busbar assembly opposite to the cell assembly. The insulating layer includes a first cover portion covering at least a portion of the busbar assembly and a second cover portion covering at least a portion of the through-hole. A gap is formed between the second cover portion and the first cover portion.

2. The battery pack as described in claim 1, characterized in that, The first covering portion has an opening corresponding to the position of the through hole, and the second covering portion is located inside the opening.

3. The battery pack as described in claim 2, characterized in that, The insulating layer further includes a connecting portion that connects the edge of the second covering portion and the edge of the opening.

4. The battery pack as described in claim 3, characterized in that, The through hole is an arc-shaped hole extending circumferentially along the central axis of the corresponding battery cell, and the extension direction of the second cover is consistent with the extension direction of the through hole.

5. The battery pack as described in claim 4, characterized in that, The connecting portion is located on the side of the second covering portion near the central axis of the corresponding battery cell.

6. The battery pack according to any one of claims 1 to 5, characterized in that, On a projection plane perpendicular to the height direction, the orthographic projection of the second covering portion covers the orthographic projection of the through hole.

7. The battery pack as described in claim 6, characterized in that, The first cover is bonded to the side of the busbar assembly opposite to the cell assembly; and / or, the second cover is bonded to the side of the busbar assembly opposite to the cell assembly.

8. The battery pack as described in claim 6, characterized in that, The bracket has a protrusion on the side opposite to the cell assembly, and the through hole penetrates the protrusion along the height direction; The first cover is bonded to the surface of the protrusion facing away from the cell assembly; and / or, the second cover is bonded to the surface of the protrusion facing away from the cell assembly.

9. The battery pack as described in claim 8, characterized in that, On a projection plane perpendicular to the height direction, the orthographic projection of the first covering portion near the edge of the second covering portion lies within the orthographic projection of the protrusion; and / or, On a projection plane perpendicular to the height direction, the orthographic projection of the edge of the second covering portion lies within the orthographic projection of the protrusion.

10. The battery pack according to any one of claims 1 to 5, characterized in that, The bracket has through holes corresponding to the pressure relief holes of the multiple battery cells; the insulating layer includes multiple second covering parts, the number of which is equal to the number of the multiple through holes, and they are arranged in a one-to-one correspondence.

11. The battery pack according to any one of claims 1 to 5, characterized in that, The battery pack also includes expanding foam filling the gaps between the battery cells. The end face of the first end of the battery cell is provided with a terminal post connected to the busbar. The first end of the battery cell protrudes from the side of the expanding foam. The height of the end face of the first end of the battery cell relative to the side of the expanding foam is greater than or equal to 5 mm and less than or equal to 10 mm.

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