Top cover assembly, battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and provides a top cover assembly, a battery cell and a battery pack, the top cover assembly comprises a top cover body, a pole and an explosion-proof valve; a first through hole and a second through hole which penetrate through the top cover body are formed in the top cover body, and the first through hole and the second through hole are arranged at an interval in the length direction of the top cover body; in the area where the second through hole is located, the top cover body is bent to form a boss protruding towards one side. The pole column is arranged in the first through hole in a penetrating manner and is electrically connected with the tab of the battery cell; the anti-explosion valve comprises a mounting seat and a valve body, the mounting seat is mounted on the inner wall of the side, deviating from the tab, of the second through hole, and the valve body is mounted on the side, facing the tab, of the mounting seat in a settling manner. According to the top cover assembly provided by the invention, the mechanical strength of the battery cell can be improved, thermoelectric separation of the pole and the anti-explosion valve is realized, the heat dissipation efficiency of the battery cell is improved, the use temperature of the battery cell is controlled, the pole and the anti-explosion valve are effectively protected, and the safety performance of the battery cell is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a top cover assembly, a battery cell and a battery pack. BACKGROUND

[0002] With the rapid development of new energy vehicles and energy storage devices, the requirements for structural safety and energy density of batteries are increasing. The battery cell is the smallest unit in the battery cell module. In the prior art, the battery cell is composed of a top cover assembly, a pole group and a shell. The top cover assembly and the shell are fixedly connected by welding to form a closed space for accommodating the pole group. The pole is arranged in the top cover assembly and electrically connected with the pole tab of the pole group.

[0003] Currently, the battery cell only contacts other structures in the battery pack through the pole. When the upper surface of the battery cell is stressed, the pole is directly stressed. The risk of short circuit of the battery cell is high, and the structural strength is low. In addition, when the battery cell is cooled, heat is only conducted through the pole and the heat conduction layer, and the cooling effect is poor. SUMMARY

[0004] The present application provides a top cover assembly, a battery cell and a battery pack to solve the problem of low strength and poor heat dissipation of the battery cell caused by the top cover assembly only being stressed and conducting heat through the pole in the prior art.

[0005] To solve the above technical problems, the present application is implemented as follows: In a first aspect, the present application provides a top cover assembly, comprising: a top cover body, a first through hole and a second through hole penetrating the top cover body are formed, the first through hole and the second through hole are arranged at intervals along the length direction of the top cover body; in the area where the second through hole is located, the top cover body is bent to form a boss protruding towards one side; a pole arranged in the first through hole and electrically connected with the pole tab of the battery cell; an explosion-proof valve comprising a mounting seat and a valve body, the mounting seat is mounted to the inner wall of the side of the second through hole away from the pole tab, and the valve body is installed on the side of the mounting seat facing the pole tab.

[0006] According to the top cover assembly provided by the present application, the second through hole is a sunken boss hole, the mounting seat comprises a seat body and a flange, the seat body is connected with the flange, the seat body extends circumferentially around the inner wall of the second through hole, and the valve body is installed on the side of the seat body close to the pole tab. The flange is arranged on the step surface of the sunken boss hole circumferentially around the second through hole.

[0007] According to the top cover assembly provided by the application, along the height direction of the top cover body, the height of the top cover body is T1, the wall thickness of the top wall of the boss is T2, the thickness of the inclined edge of the boss is T3, and the height of the boss relative to the side of the top cover body away from the tab is H1, and the following conditions are met: 2.0mm≤T1≤2.5mm, 0.8≤T2 / T1≤1.1, 0.8≤T3 / T1≤1.1, 1.5≤H1 / T1≤2.0; And / or, along the height direction of the top cover body, the height of the boss is H1, and the depth of the second through hole is H2, and the following condition is met: 0.6≤H2 / H1≤0.95.

[0008] According to the top cover assembly provided by the application, along the height direction of the top cover body, the second through hole is formed with a sink groove part protruding from the boss towards the side of the tab, and the bottom wall of the sink groove part is provided with a reinforcing rib.

[0009] According to the top cover assembly provided by the application, the upper surface area of the boss is S1, the area of the second through hole is S2, and the projection area of the reinforcing rib on the top cover body is S3, and the following conditions are met: 0.15≤S2 / S1≤0.2, 0.15≤S3 / S2≤0.25; And / or, the reinforcing rib is provided with a plurality of reinforcing ribs, and the plurality of reinforcing ribs are arranged along the groove bottom of the second through hole, and part of the plurality of reinforcing ribs are arranged along the length direction of the top cover body, and the remaining reinforcing ribs are arranged along the width direction of the top cover body.

[0010] According to the top cover assembly provided by the application, the first insulating part is further provided. The first insulating part is arranged on the side of the top cover body facing the tab, and the first insulating part is formed with an avoidance groove for avoiding the sink groove part in the area corresponding to the explosion-proof valve, and the groove bottom of the avoidance groove is provided with an exhaust hole. The distance between the side of the sink groove part facing the tab and the groove bottom of the avoidance groove is C, and the following condition is met: 1mm≤C≤2mm; Along the length direction of the top cover body, the distance between the groove walls of the opposite sides of the avoidance groove is L2, and the distance between the outer walls of the opposite sides of the sink groove part is L1, and the following condition is met: 3mm≤(L2-L1) / 2≤6mm.

[0011] According to the top cover assembly provided by the application, the distance between the outer wall of the mounting seat and the inner wall of the second through hole is A, and the following condition is met: 0.2mm≤A≤0.5mm; And / or, the distance between the side of the valve body facing the tab and the side of the reinforcing rib facing the valve body is B, and the following condition is met: 1mm≤B≤2mm.

[0012] According to a top cover assembly provided by the present invention, the explosion-proof valve is an aluminum alloy component, wherein the tensile strength of the aluminum alloy component is σb, the yield strength is σs, and the elongation is F, satisfying: 70MPa≤σb≤85MPa, σs≥30MPa, 36%≤F≤60%.

[0013] In a second aspect, the present invention provides a battery cell comprising: an electrode assembly, a housing, and a top cover assembly as described above; The electrode assembly is located inside the housing, the top cover assembly is fixed to the opening end of the housing, and the electrode assembly is electrically connected to the top cover assembly through electrode tabs.

[0014] Thirdly, the present invention provides a battery pack, comprising: a busbar, a housing, and battery cells as described above; The housing forms a receiving cavity, and multiple battery cells are provided, with the multiple battery cells stacked in the receiving cavity; the busbar is connected to the terminals of the multiple battery cells; The upper surface of the boss is bonded to the box body through an adhesive layer.

[0015] The top cover assembly, battery cell, and battery pack provided by this invention form a boss by bending the top cover body in the area where the explosion-proof valve is located. This not only enhances the structural strength of the top cover assembly and thus improves the mechanical strength of the battery cell, achieving thermoelectric separation of the terminals and the explosion-proof valve, but also increases the surface area of ​​the top cover body, thereby increasing the heat dissipation area of ​​the top cover body and the bonding area with the thermally conductive layer, improving the heat dissipation efficiency of the battery cell and controlling the operating temperature of the battery cell. Furthermore, the explosion-proof valve includes a mounting base and a valve body. By installing the valve body in a recessed manner at the bottom of the mounting base, the terminals and the explosion-proof valve are effectively protected, improving the safety performance of the battery cell. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a three-dimensional structural diagram of the top cover assembly in the prior art.

[0018] Figure 2 This is a three-dimensional structural diagram of a battery pack in the prior art.

[0019] Figure 3 This is a front view of a battery cell in the prior art.

[0020] Figure 4 It is in the existing technology Figure 3 A magnified view of the X-section.

[0021] Figure 5 This is an exploded view of the top cover body and the explosion-proof valve provided by the present invention.

[0022] Figure 6 This is a bottom view of the top cover assembly provided by the present invention.

[0023] Figure 7 This is a three-dimensional structural diagram of the explosion-proof valve provided by the present invention.

[0024] Figure 8 This is a top view of the explosion-proof valve provided by the present invention.

[0025] Figure 9 This invention provides Figure 8 UU sectional view.

[0026] Figure 10 This invention provides Figure 9 Enlarged view of part O.

[0027] Figure 11 This is a top view of the top cover body provided by the present invention.

[0028] Figure 12 This invention provides Figure 11 VV sectional view.

[0029] Figure 13 This is a top view of the assembly of the top cover body and the explosion-proof valve provided by the present invention.

[0030] Figure 14 This invention provides Figure 13 YY sectional view.

[0031] Figure 15 This invention provides Figure 14 A magnified view of part K.

[0032] Figure 16 This is one of the three-dimensional structural schematic diagrams of the top cover assembly provided by the present invention.

[0033] Figure 17 This is the second three-dimensional structural schematic diagram of the top cover assembly provided by the present invention.

[0034] Figure 18 This is a top view of the top cover assembly provided by the present invention.

[0035] Figure 19 This invention provides Figure 18 ZZ cross-sectional view.

[0036] Figure 20 This invention provides Figure 19 A magnified view of the R part.

[0037] Figure label: 1. Top cover assembly; 11. Top cover body; 12. Pole post; 13. Explosion-proof valve; 14. First insulating component; 15. Reinforcing rib; 111. First through hole; 112. Second through hole; 113. Boss; 131. Seat; 132. Edge; 133. Valve body; 141. Vent hole; 142. Clearance groove; 1131. Settlement section; 2. Electrode group; 21. Electrode ear; 100, busbar; 200, battery cell. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0039] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of clarifying the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0041] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] The following is combined Figures 1 to 20 The top cover assembly, battery cell, and battery pack provided in this invention will be described in detail through specific embodiments and application scenarios.

[0044] Firstly, such as Figure 5 and Figure 7 As shown, this embodiment provides a top cover assembly 1, including: a top cover body 11, a pole post 12, and an explosion-proof valve 13.

[0045] The top cover body 11 has a first through hole 111 and a second through hole 112 that penetrate the top cover body 11. The first through hole 111 and the second through hole 112 are spaced apart along the length of the top cover body 11. In the area where the second through hole 112 is located, the top cover body 11 is bent to form a boss 113 that protrudes to one side. The pole post 12 is inserted through the first through hole 111 and is electrically connected to the tab 21 of the battery cell 200.

[0046] The explosion-proof valve 13 includes a mounting base and a valve body 133. The mounting base is installed on the inner wall of the second through hole 112 on the side away from the electrode tab 21, and the valve body 133 is installed in a sinking manner on the side of the mounting base facing the electrode tab 21.

[0047] Understandably, such as Figures 1 to 4As shown, in the prior art, the electrode group 2 of the battery cell 200 is electrically connected to the terminal post 12 on the top cover assembly 1 via the electrode tab 21. The top cover assembly 1 is installed at the open end of the housing. The terminal post 12 protrudes from both sides of the top cover body 11 through the first through hole 111. One end of the terminal post 12 is welded to the electrode tab 21 of the battery cell 200, and the other end is used to connect to the tab on the busbar 100. When the battery cell 200 is assembled into a battery pack, since all other structures on the top cover body 11 except for the terminal post 12 are flush with the top cover body 11, the battery cell 200 only contacts other components of the battery pack through the terminal post 12.

[0048] In this embodiment, a boss 113 is provided in the area where the explosion-proof valve 13 is located, giving the space where the explosion-proof valve 13 is located a raised structure. When the surface of the battery cell 200 is subjected to external impact, the boss 113 can share the external force on the terminal post 12. Furthermore, since the boss 113 has a certain structural strength, it can support the top cover body 11, preventing short circuits in the battery cell 200 and improving the mechanical strength of the entire battery cell package.

[0049] Meanwhile, when the cells 200 are stacked to form a cell module, the upper surface of the cell 200 can conduct heat dissipation through contact with the heat-conducting layer via the electrode post 12, and also through contact with the heat-conducting layer via the boss 113. Compared with the prior art, where most of the top cover body 11 can only dissipate heat through thermal radiation, the contact heat conduction effect of the boss 113 in this embodiment is better, which is more conducive to the heat dissipation of the cell 200, more conducive to controlling the operating temperature of the cell 200, and extending the service life of the cell 200.

[0050] Furthermore, since the explosion-proof valve 13 is located on the boss 113, the explosion-proof valve 13 and the pole post 12 are at different spatial heights, which can also isolate the pole post 12 and the explosion-proof valve 13, achieve thermoelectric separation, and improve the safety performance of the battery cell 200.

[0051] In the prior art, in the battery cell 200, sufficient height needs to be reserved between the electrode group 2 and the top cover body 11 to provide bending space for the tab 21. For example... Figure 3 and Figure 4 As shown, the height H of the insulating component of the top cover body 11 is usually in the range of 6≤H≤9, and the gap H0 between the pole group 2 and the top cover body 11 is usually in the range of 4≤H0≤6.

[0052] In this embodiment, the top cover body 11 is bent to form a protrusion 113. The protrusion 113 is a hollow platform with a accommodating space facing the side of the electrode 21. The electrode 21 can be accommodated within the accommodating space, thereby reducing the height gap between the electrode group 2 and the top cover body 11 and increasing the capacity of the battery cell 200. Furthermore, the protrusion height of the protrusion 113 faces outward from the top cover body 11, also filling the space between the electrode post 12 and the explosion-proof valve 13, thus increasing the energy density of the battery cell 200.

[0053] Furthermore, to reduce the height of the explosion-proof valve 13 relative to the top surface of the boss 113, the explosion-proof valve 13 in this embodiment includes a mounting base and a valve body 133. The mounting base is installed on the inner wall of the second through hole 112, and the upper surface of the mounting base is flush with the upper surface of the boss 113. Since the mounting base extends along the height direction of the top cover body 11, the valve body 133 is installed on the side of the mounting base away from the top surface of the boss 113, closer to the tab 21. The valve body 133 is installed in a recessed manner relative to the top surface of the boss 113 on the inner wall of the second through hole 112. Therefore, the height of the mounting base is the height of the valve body 133 relative to the top surface of the boss 113. By installing the valve body 133 in a recessed manner, the valve body 133 and the top surface of the boss 113 are not located on the same plane. When the top surface of the boss 113 is deformed under pressure, the impact on the valve body 133 of the explosion-proof valve 13 is reduced.

[0054] The top cover assembly 1 provided by the present invention forms a boss 113 by bending the top cover body 11 in the area where the explosion-proof valve 13 is located. This not only enhances the structural strength of the top cover assembly 1 through the boss 113, thereby improving the mechanical strength of the battery cell 200, but also achieves thermoelectric separation of the electrode post 12 and the explosion-proof valve 13. Furthermore, the boss 113 increases the surface area of ​​the top cover body 11, thereby increasing the heat dissipation area of ​​the top cover body 11 and the bonding area with the heat-conducting layer, improving the heat dissipation efficiency of the battery cell 200, and controlling the operating temperature of the battery cell 200. In addition, the explosion-proof valve 13 includes a mounting base and a valve body 133. By sinking the valve body 133 to the bottom of the mounting base, the electrode post 12 and the explosion-proof valve 13 are effectively protected, improving the safety performance of the battery cell 200.

[0055] like Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, the second through hole 112 in this embodiment is a countersunk hole. The mounting base includes a base body 131 and an overlap 132. The base body 131 is connected to the overlap 132. The base body 131 extends circumferentially around the inner wall of the second through hole 112. The valve body 133 is mounted on the side of the base body 131 near the electrode tab 21.

[0056] The overlap 132 is circumferentially overlapped on the stepped surface of the recessed platform hole around the second through hole 112.

[0057] Understandably, to increase the connection strength between the mounting base and the second through hole 112, the mounting base in this embodiment includes a base body 131 and an overlap 132, and the second through hole 112 is configured as a countersunk hole. Both the overlap 132 and the base body 131 extend circumferentially along the inner wall of the second through hole 112. The overlap 132 is mounted on the stepped surface of the countersunk hole, ensuring that the mounting base will not slip off the wall of the second through hole 112, thus improving the connection reliability between the mounting base and the second through hole 112. One side of the base body 131 is connected to the overlap 132, and the other side has a mounting hole for mounting the valve body 133.

[0058] Specifically, the overlap 132 can be welded to the stepped surface of the countersunk hole, which is beneficial to the connection strength and stability of the overlap 132 and the stepped surface.

[0059] Wherein, along the height direction of the top cover body 11, the height of the overlap 132 is T4, the thickness of the valve body 133 is T5, and the distance between the valve body 133 and the overlap 132 is H3, satisfying: 0.5mm≤T4≤0.7mm, 0.45≤T5 / T4≤0.55, 2.1≤H3 / T4≤2.8.

[0060] The valve body 133 has grooves to allow the explosion-proof valve 13 to burst at the grooves in the event of thermal failure of the battery cell 200, thereby precisely controlling the location and direction of the rupture and achieving directional pressure relief. Since the valve body 133 is located at the bottom of the seat 131 and the overlap 132 is located at the top of the seat 131, the heat conduction path between the welded position of the overlap 132 and the groove on the valve body 133 is relatively long, resulting in minimal thermal impact on the groove during welding of the overlap 132. Furthermore, when the boss 113 undergoes slight deformation, the seat 131 and the overlap 132 can absorb a certain amount of deformation, reducing the impact of external forces on the groove, ensuring the integrity of the groove, and improving the safety performance of the explosion-proof valve 13.

[0061] To ensure the connection strength between the overlap 132 and the countersunk hole and the base 131, the height of the overlap 132 needs to be limited to a certain range so that the overlap 132 can be flush with the top of the countersunk hole after assembly, and can also withstand the slight deformation of the boss 113.

[0062] Specifically, the height T4 of the overlap 132 can be 0.5mm, 0.6mm, or 0.7mm.

[0063] Furthermore, the thickness of the valve body 133 and the height of the overlap 132 also need to meet certain ranges to ensure the strength of the valve body 133.

[0064] Specifically, T5 / T4 can be 0.45, 0.5, or 0.55.

[0065] Meanwhile, the distance H3 between the valve body 133 and the overlap 132 can characterize the length of the heat conduction path between the groove on the valve body 133 and the overlap 132. The ratio of the length of the heat conduction path to the height of the overlap 132 reflects the proportion of the thermal influence of the overlap 132 on the groove. When the length of the heat conduction path is more than twice that of the overlap 132, the structural strength of the overlap 132 can be ensured, while preventing the groove from being damaged by thermal influence.

[0066] Specifically, H3 / T4 can be 2.1, 2.45, or 2.8.

[0067] This embodiment further limits the height of the overlap 132, the ratio of the thickness of the valve body 133 to the height of the overlap 132, and the ratio of the distance between the valve body 133 and the overlap 132 to the height of the overlap 132. This effectively protects the heat-affected zone of the valve body 133 during welding of the overlap 132 and the tensile force on the valve body 133 when the boss 113 deforms. This ensures the reliability and stability of the explosion-proof valve 13 and improves the safety performance of the battery cell 200.

[0068] like Figure 8 and Figure 9 As shown, the valve body 133 of this embodiment has circumferential grooves. Along the height direction of the top cover body 11, the wall thickness at the groove position is T6, which satisfies: 0.3≤T6 / T5≤0.45.

[0069] Understandably, the circumferential grooves on the valve body 133 define a complete pressure relief port through a closed annular weakened area. When the annular grooves are triggered, the entire circular area fully opens, forming a regular pressure relief channel with the largest possible area. The stress distribution is uniform and symmetrical, resulting in high consistency and reliability in the safety design. The wall thickness at the groove location is the thickness of the residual material at the groove, which determines the opening pressure of the explosion-proof valve 13. Therefore, the wall thickness at the groove location and the thickness of the valve body 133 need to meet a certain range to ensure the normal opening of the valve body 133.

[0070] Specifically, T6 / T5 can be 0.3, 0.375, or 0.45.

[0071] like Figure 9 As shown, the width of the overlap 132 along the radial direction of the second through hole 112 in this embodiment is A1, which satisfies: A1≥1mm.

[0072] Understandably, the width of the overlap 132 is the distance between the inner and outer sides of the circumferential overlap 132 around the base body 131. The overlap 132 can extend into and overlap the step surface of the countersunk hole. The width of the overlap 132 needs to meet a certain range to ensure the structural strength of the overlap 132 and its proper assembly with the countersunk hole.

[0073] Specifically, the width A1 of the overlap 132 can be 1mm, 1.5mm, or 2mm.

[0074] like Figure 11 and Figure 12 As shown, in this embodiment, along the height direction of the top cover body 11, the thickness of the top cover body 11 is T1; the wall thickness of the top wall of the boss 113 is T2, the thickness of the inclined side of the boss 113 is T3, and the height of the boss 113 relative to the side of the top cover body 11 away from the tab is H1, satisfying: 2.0mm≤T1≤2.5mm, 0.8≤T2 / T1≤1.1, 0.8≤T3 / T1≤1.1, 1.5≤H1 / T1≤2.0.

[0075] Understandably, in order to ensure the structural strength of the boss 113, the ratio of the height of the top cover body 11, the ratio of the wall thickness of the inclined side of the boss 113 to the height of the top cover body 11, the ratio of the thickness of the top wall of the boss 113 to the height of the top cover body 11, and the ratio of the height of the boss 113 to the height of the top cover body 11 all need to meet certain ranges to ensure the support strength and structural strength of the boss 113.

[0076] Specifically, T1 can be 2mm, 2.25mm, or 2.5mm; T2 / T1 can be 0.8, 0.95, or 1.1; T3 / T1 can be 0.8, 0.95, or 1.1; H1 / T1 can be 1.5, 1.75, or 2.0.

[0077] like Figure 10 and Figure 11 As shown, along the height direction of the top cover body 11, the height of the boss 113 in this embodiment is H1, and the depth of the second through hole 112 is H2, satisfying: 0.6≤H2 / H1≤0.95.

[0078] Understandably, when stamping the second through hole 112, due to the limitations of the stamping process, the height of the second through hole 112 and the height of the boss 113 must meet a certain range.

[0079] Specifically, H2 / H1 can be 0.6, 0.775, or 0.95.

[0080] like Figure 6 , Figure 11 and Figure 12 As shown, along the height direction of the top cover body 11, the second through hole 112 in this embodiment protrudes from the boss 113 on the side facing the tab 21 to form a recessed groove 1131, and the bottom wall of the recessed groove 1131 is provided with a reinforcing rib 15.

[0081] Understandably, since a reinforcing rib 15 needs to be provided on the side of the second through hole 112 near the tab 21, and an explosion-proof valve 13 needs to be installed on the reinforcing rib 15, the thickness of the top wall of the boss 113 cannot meet the requirements for the arrangement of the second through hole 112 in the height direction of the top cover body 11. In this embodiment, a recessed portion 1131 is formed by the boss 113 protruding from the second through hole 112, and a reinforcing rib 15 is provided on the bottom wall of the recessed portion 1131. The end of the reinforcing rib 15 abuts against the inner wall of the recessed portion 1131 to provide stable support for the inner wall of the recessed portion 1131, thereby enhancing the structural strength of the second through hole 112 and preventing deformation or cracking of the second through hole 112 caused by the installation and opening of the explosion-proof valve 13.

[0082] Specifically, one or more reinforcing ribs 15 can be installed. Multiple reinforcing ribs 15 can be installed at intervals or in an alternating manner.

[0083] In this embodiment, the upper surface area of ​​the boss 113 is S1, the area of ​​the second through hole 112 is S2, and the projected area of ​​the reinforcing rib 15 on the top cover body 11 is S3, satisfying the following: 0.15≤S2 / S1≤0.2, 0.15≤S3 / S2≤0.25.

[0084] Understandably, the boss 113 covers the upper surface of the top cover body 11 next to the pole post 12. In order to ensure the structural strength of the boss 113, the ratio of the area of ​​the second through hole 112 to the upper surface area of ​​the boss 113 must meet a certain range.

[0085] Specifically, S2 / S1 can be 0.15, 0.175, or 0.2.

[0086] Furthermore, since the reinforcing rib 15 is located on the lower side of the explosion-proof valve 13 and inside the exhaust channel of the explosion-proof valve 13, in order not to obstruct the smooth flow of the exhaust channel, the ratio of the projected area of ​​the reinforcing rib 15 on the top cover body 11 to the area of ​​the second through hole 112 must meet a certain range, so as to avoid the reinforcing rib 15 being too large and affecting the exhaust channel, or the reinforcing rib 15 being too small and having poor support effect.

[0087] Specifically, S3 / S2 can be 0.15, 0.2, or 0.25.

[0088] like Figure 11 As shown, this embodiment has multiple reinforcing ribs 15. The multiple reinforcing ribs 15 are arranged at intervals along the bottom of the second through hole 112. Some of the multiple reinforcing ribs 15 are arranged along the length direction of the top cover body 11, and the remaining reinforcing ribs 15 are arranged along the width direction of the top cover body 11.

[0089] Understandably, the reinforcing ribs 15 in this embodiment form a grid-like reinforcement structure through their arrangement in the length and width directions, improving local stability and stiffness, creating an efficient force transmission path, and maximizing material savings for the reinforcing ribs 15. The gaps between the reinforcing ribs 15 in the length and width directions allow for the passage of high-temperature exhaust from the battery cell 200 without affecting the smoothness of the exhaust channel of the battery cell 200.

[0090] like Figure 17 , Figure 18 , Figure 19 and Figure 20 As shown, the top cover assembly 1 in this embodiment further includes a first insulating member 14.

[0091] The first insulating member 14 is provided on the side of the top cover body 11 facing the electrode tab 21. The area of ​​the first insulating member 14 corresponding to the explosion-proof valve 13 has a relief groove 142 for avoiding the sink 1131. The bottom of the relief groove 142 has an exhaust hole 141.

[0092] The distance C between the side of the settling trough 1131 facing the tab 21 and the bottom of the clearance groove 142 satisfies: 1mm≤C≤2mm.

[0093] Along the length of the top cover body 11, the spacing between the groove walls on opposite sides of the clearance groove 142 is L2, and the spacing between the outer walls on opposite sides of the sink 1131 is L1, satisfying: 3mm≤(L2-L1) / 2≤6mm.

[0094] Understandably, since the recessed portion 1131 is formed by the protrusion of the boss 113, in the height direction of the top cover body 11, the recessed portion 1131 protrudes towards the tab 21 relative to the top wall of the boss 113. The first insulating member 14, located on the lower side of the boss 113, needs to avoid the recessed portion 1131 in the area of ​​the second through hole 112, thus forming a relief groove 142. The bottom of the relief groove 142 has multiple vent holes 141, which are evenly spaced. The multiple vent holes 141 and the explosion-proof valve 13 form an exhaust channel, which can quickly exhaust the high-temperature gas to the outside of the battery cell 200 when the battery cell 200 fails due to high temperature, ensuring the safety of the battery cell 200.

[0095] Since the bottom of the settling tank 1131 is provided with a reinforcing rib 15, high-temperature gas enters the explosion-proof valve 13 through the gap between the exhaust port 141 and the reinforcing rib 15. In order to ensure smooth exhaust of the explosion-proof valve 13, the bottom end of the settling tank 1131 and the bottom of the clearance groove 142 need to have a certain range of distance.

[0096] Specifically, C can be 1mm, 1.5mm, or 2mm.

[0097] To ensure the assembly reliability of the settling tank 1131 and the clearance groove 142, and to ensure that the high-temperature gas entering the clearance groove 142 through the exhaust port 141 has sufficient space to be accommodated, and through the gap of the reinforcing rib 15, the difference between the groove wall on the opposite side of the clearance groove 142 and the outer wall on the opposite side of the settling tank 1131 needs to meet a certain range.

[0098] Specifically, (L2-L1) / 2 can be 3mm, 4.5mm, or 6mm.

[0099] like Figure 13 , Figure 14 and Figure 15 As shown, the distance between the outer wall of the seat 131 and the inner wall of the second through hole 112 in this embodiment is A, which satisfies: 0.2mm≤A≤0.5mm.

[0100] Understandably, when assembling the mounting base 131 with the countersunk hole, after the overlap 132 is fixed to the stepped surface of the countersunk hole, the distance between the outer wall of the mounting base 131 and the inner wall of the second through hole 112 needs to meet a certain range to ensure smooth assembly.

[0101] Specifically, the distance A between the outer wall of the base 131 and the inner wall of the second through hole 112 can be 0.2mm, 0.35mm, or 0.5mm.

[0102] like Figure 13 , Figure 14 and Figure 15 As shown, in this embodiment, the distance between the side of the valve body 133 facing the tab 21 and the side of the reinforcing rib 15 facing the valve body 133 is B, which satisfies: 1mm≤B≤2mm.

[0103] Understandably, in order to ensure that the bottom of the valve body 133 does not interfere with the reinforcing rib 15 when the valve body 133 is installed on the mounting base, and to leave a gap between the valve body 133 and the reinforcing rib 15 to facilitate the flow of high-temperature gas, the distance between the side of the valve body 133 facing the tab 21 and the side of the reinforcing rib 15 facing the valve body 133 needs to meet a certain range.

[0104] Specifically, the spacing B can be 1mm, 1.5mm, or 2mm.

[0105] In this embodiment, the explosion-proof valve 13 is made of aluminum alloy. The tensile strength of the aluminum alloy is σb, the yield strength is σs, and the elongation is F, satisfying the following: 70MPa≤σb≤85MPa, σs≥30MPa, 36%≤F≤60%.

[0106] Understandably, aluminum alloy components have a low density, good heat transfer properties, and good ductility, making them suitable for manufacturing explosion-proof valve 13 to ensure precise control over burst pressure and rapid response and pressure relief. The tensile strength, yield strength, and elongation of the aluminum alloy components used to manufacture explosion-proof valve 13 need to meet certain ranges to ensure the consistency and accuracy of explosion pressure control by explosion-proof valve 13.

[0107] Specifically, σb can be 70 MPa, 77.5 MPa, or 85 MPa. σs can be 30 MPa, 35 MPa, or 40 MPa. F can be 36%, 48%, or 60%.

[0108] In one example, the aluminum alloy used in this embodiment is designated Al1060, and its chemical composition is as follows: Al > 99.6%, Mn ≤ 0.03%, Fe ≤ 0.35%, Si ≤ 0.25%.

[0109] like Figure 13 As shown, along the length of the top cover body 11, the distance between the bend of the boss 113 and the pole post 12 in this embodiment is a, where a satisfies: a≥2.5mm.

[0110] Understandably, the bend of the boss 113 needs to be spaced a certain distance from the pole post 12 to prevent the boss 113 from colliding with the pole post 12 when under force, thus damaging the pole post 12.

[0111] Specifically, 'a' can be 2.5mm, 3mm, or 3.5mm.

[0112] like Figure 11 As shown, the length of the top cover body 11 in this embodiment is L, and L satisfies: 150mm≤L≤300mm.

[0113] The width of the top cover body 11 is W, and W satisfies: 25mm≤W≤75mm.

[0114] It is understood that the length and width of the top cover body 11 in this embodiment are limited to accommodate the assembly requirements of different battery cell capacities 200, while avoiding excessive length that could lead to material redundancy or structural deformation.

[0115] Specifically, the length L of the top cover body 11 can be 150mm, 225mm, or 300mm. The width W of the top cover body 11 can be 25mm, 50mm, or 75mm.

[0116] like Figure 14 and Figure 15 As shown, the boss 113 in this embodiment is a cone-shaped platform; the taper of the cone-shaped platform is β, and β satisfies: 20°≤β≤25°.

[0117] Understandably, the conical pedestal helps to disperse concentrated loads, reduce stress concentration at the mating joint, improve the load-bearing capacity and stability of the boss 113, avoid local damage, and is easy to process due to its regular shape.

[0118] Specifically, the taper β of the truncated cone can be 20°, 22.5°, or 25°.

[0119] like Figure 16 As shown, in this embodiment, the boss 113 and the top cover body 11 are integrally formed.

[0120] Understandably, the boss 113 and the top cover body 11 are made of the same piece of material. The one-piece molding structure simplifies the production process and ensures the reliability of the connection between the boss 113 and the top cover body 11.

[0121] Alternatively, the one-piece molding structure can be achieved by stamping, stretching, or embossing.

[0122] In one example, the boss 113 can be a conical platform formed by stamping. The stamping of conical platforms is easy to achieve, has a high production yield, and is easy to process and manufacture.

[0123] like Figure 16 As shown, this embodiment has two pole posts 12, which are located at both ends of the top cover body 11 along the length of the top cover body 11.

[0124] The boss 113 is located between the two pole posts 12, and the second through hole 112 is located in the middle of the boss 113.

[0125] Understandably, in this embodiment, two terminals 12 are installed on the top cover body 11, one is a positive terminal and the other is a negative terminal. Along the length of the top cover body 11, the negative terminal and the positive terminal are respectively located at both ends of the top cover body 11, and the negative terminal and the positive terminal are respectively connected to the electrode group 2 of the battery cell 200.

[0126] An explosion-proof valve 13 is provided between the positive and negative terminals, and a boss 113 is formed between the positive and negative terminals, thereby ensuring that the boss 113 disperses the pressure between the positive and negative terminals, improving the structural strength of the top cover assembly 1, and ensuring the safety of the battery cell 200.

[0127] Furthermore, the explosion-proof valve 13 is installed in the middle of the boss 113, and the distance from the positive terminal and the negative terminal is equal, which makes the structure of the top cover body 11 more regular, easier to process and manufacture, and can effectively isolate the explosion-proof valve 13 from the positive terminal and the negative terminal.

[0128] Secondly, this embodiment provides a battery cell 200, including: an electrode group 2, a housing, and a top cover assembly 1 as described above.

[0129] The electrode assembly 2 is located inside the housing, and the top cover assembly 1 is fixed to the opening end of the housing. The electrode assembly 2 is electrically connected to the top cover assembly 1 through the electrode tab 21.

[0130] Specifically, since the battery cell 200 includes a top cover assembly 1, and the specific structure of the top cover assembly 1 is as described in the above embodiments, the battery cell 200 shown in this embodiment includes all the technical solutions of the above embodiments. Therefore, it has at least all the beneficial effects obtained by all the technical solutions of the above embodiments, which will not be described in detail here.

[0131] Understandably, the electrode assembly 2 is installed inside the housing, and the top cover assembly 1 is placed over the opening of the housing. The electrode assembly 2 is electrically connected to the electrode post 12 of the top cover assembly 1 through the electrode tab 21 to achieve current transmission. Since the top cover assembly 1 bends to form a protrusion 113 in the area where the explosion-proof valve 13 is located on the top cover body 11, the contact heat dissipation area on the upper surface of the top cover body 11 is increased, which is beneficial to controlling the operation of the battery cell 200, extending the service life of the battery cell 200, and increasing the stress area of ​​the top cover body 11, avoiding the electrode post 12 being subjected to stress alone, thus improving the safety performance of the battery cell 200. Furthermore, the explosion-proof valve 13 includes a mounting base and a valve body 133. The valve body 133 is recessed and installed at the bottom of the mounting base through the mounting base, effectively protecting the electrode post 12 and the explosion-proof valve 13, thus improving the safety performance of the battery cell 200.

[0132] Taking the top cover assembly 1 with two pole posts 12 as an example, the assembly process of pole group 2 and top cover assembly 1 is described. First, the pole group 2 and the pole tabs 21 are in a flat state. The two pole groups 2 are placed on both sides of the top cover body 11 along the width direction of the top cover body 11. The two pole tabs 21 are aligned with the two pole posts 12 respectively, and the pole tabs 21 are welded to the pole posts 12. Then, the two pole groups 2 are rotated 90° away from the top cover assembly 1, so that the top cover assembly 1 is located on the side of the pole group 2. Finally, the pole group 2 is installed into the housing, and the top cover assembly 1 is located at the opening end of the housing.

[0133] In this embodiment, the production line tests various parameters of the top cover assembly 1 to verify the technical effects of different data. The following parameters are changed sequentially: the thickness T1 of the top cover body 11; the height H1 of the boss 113; the depth H2 of the second through hole 112; the ratio H1 / T1 of the height of the boss 113 to the thickness of the top cover body 11; the ratio H2 / H1 of the depth of the second through hole 112 to the height of the boss 113; the upper surface area S1 of the boss 113; the area S2 of the second through hole 112; the projected area S3 of the reinforcing rib 15 on the top cover body 11; and the area of ​​the outer wall of the seat 131 and the second through hole 112. The following parameters are used to perform simulation analysis on the battery cell 200: the distance A between the inner walls of the battery cell, the distance B between the side of the valve body 133 facing the electrode 21 and the side of the reinforcing rib 15 facing the valve body 133, the distance C between the side of the sink 1131 facing the electrode 21 and the bottom of the clearance groove 142, the ratio S2 / S1 of the area of ​​the second through hole 112 to the upper surface area of ​​the boss 113, and the ratio S3 / S2 of the projected area of ​​the reinforcing rib 15 on the top cover body 11 to the area of ​​the second through hole 112.

[0134] It is evident that when the structural design of the top cover assembly 1 meets the above requirements, the production of the top cover assembly 1 is without abnormalities and the structural strength meets the requirements. Conversely, local deformation is likely to occur, affecting the safety performance of the top cover body 11 or the explosion-proof valve 13.

[0135] Table 1

[0136] Table 2

[0137] Thirdly, this embodiment provides a battery pack, including: a busbar 100, a housing, and the aforementioned battery cells 200.

[0138] The housing forms a receiving cavity, and multiple battery cells 200 are provided, with multiple battery cells 200 stacked in the receiving cavity; the busbar 100 is connected to the terminal post 12 of the multiple battery cells 200, and the upper surface of the boss 113 is bonded to the housing through an adhesive layer.

[0139] Specifically, since the battery pack includes a cell 200, and the specific structure of the cell 200 is as described in the above embodiments, the battery pack shown in this embodiment includes all the technical solutions of the above embodiments. Therefore, it has at least all the beneficial effects achieved by all the technical solutions of the above embodiments, which will not be described in detail here.

[0140] Understandably, after the battery cells 200 are grouped together in the receiving cavity, the terminal 12 of each battery cell 200 is welded to the tab on the busbar 100. The busbar 100 connects the stacked battery cells 200 into groups, and the tab is fixedly connected to the housing through a heat-conducting layer. In this embodiment, a boss 113 is provided on the top cover body 11 in the area where the explosion-proof valve 13 is located. An adhesive layer is provided on the top surface of the boss 113. After the boss 113 abuts against the housing, it is glued and fixed, so that the boss 113 can transfer heat through direct contact with the housing. Since the explosion-proof valve 13 is installed in a recessed manner on the bottom of the mounting base through the seat 131, the terminal 12 and the explosion-proof valve 13 are effectively protected, and the safety performance of the battery cell 200 is improved.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A top cover assembly, applied to a battery cell, characterized in that, include: The top cover body has a first through hole and a second through hole that penetrate the top cover body. The first through hole and the second through hole are spaced apart along the length direction of the top cover body. In the area where the second through hole is located, the top cover body is bent to form a boss that protrudes to one side. The electrode post is inserted through the first through hole and electrically connected to the electrode tab of the battery cell; An explosion-proof valve includes a mounting base and a valve body. The mounting base is installed on the inner wall of the second through hole on the side opposite to the electrode tab, and the valve body is recessed and installed on the side of the mounting base facing the electrode tab.

2. The top cover assembly according to claim 1, characterized in that, The second through hole is a countersunk hole. The mounting base includes a base body and an overlap. The base body is connected to the overlap. The base body extends circumferentially around the inner wall of the second through hole. The valve body is mounted on the side of the base body near the electrode tab. The overlapping edge is circumferentially attached to the stepped surface of the recessed hole around the second through hole.

3. The top cover assembly according to claim 1 or 2, characterized in that, Along the height direction of the top cover body, the thickness of the top cover body is T1; the wall thickness of the top wall of the boss is T2, the thickness of the inclined side of the boss is T3, and the height of the boss relative to the side of the top cover body away from the tab is H1, satisfying: 2.0mm≤T1≤2.5mm, 0.8≤T2 / T1≤1.1, 0.8≤T3 / T1≤1.1, 1.5≤H1 / T1≤2.0; And / or, along the height direction of the top cover body, the height of the boss is H1, and the depth of the second through hole is H2, satisfying: 0.6≤H2 / H1≤0.

95.

4. The top cover assembly according to claim 1, characterized in that, Along the height direction of the top cover body, the second through hole protrudes from the boss on the side facing the electrode ear to form a recessed groove, and the bottom wall of the recessed groove is provided with reinforcing ribs.

5. The top cover assembly according to claim 4, characterized in that, The upper surface area of ​​the boss is S1, the area of ​​the second through hole is S2, and the projected area of ​​the reinforcing rib on the top cover body is S3, satisfying the following: 0.15≤S2 / S1≤0.2, 0.15≤S3 / S2≤0.25; And / or, the reinforcing ribs are provided in multiples, and the multiple reinforcing ribs are arranged at intervals along the bottom of the groove of the second through hole, some of the multiple reinforcing ribs are arranged along the length direction of the top cover body, and the remaining reinforcing ribs are arranged along the width direction of the top cover body.

6. The top cover assembly according to claim 4, characterized in that, Also includes: First insulating component; The first insulating member is disposed on the side of the top cover body facing the electrode tab. The first insulating member has a relief groove in the area corresponding to the explosion-proof valve to avoid the sink. The bottom of the relief groove has an exhaust hole. The distance between the side of the sinking section facing the electrode lug and the bottom of the clearance groove is C, which satisfies: 1mm≤C≤2mm; Along the length of the top cover body, the distance between the walls of the clearance groove on opposite sides is L2, and the distance between the outer walls of the sinking part on opposite sides is L1, satisfying: 3mm≤(L2-L1) / 2≤6mm.

7. The top cover assembly according to claim 6, characterized in that, The distance A between the outer wall of the mounting base and the inner wall of the second through hole satisfies: 0.2mm≤A≤0.5mm; And / or, the distance between the side of the valve body facing the electrode lug and the side of the reinforcing rib facing the valve body is B, satisfying: 1mm≤B≤2mm.

8. The top cover assembly according to claim 1, characterized in that, The explosion-proof valve is made of aluminum alloy, and the tensile strength of the aluminum alloy is σb, the yield strength is σs, and the elongation is F, satisfying the following: 70MPa≤σb≤85MPa, σs≥30MPa, 36%≤F≤60%.

9. A battery cell, characterized in that, include: The electrode assembly, the housing, and the top cover assembly as described in any one of claims 1 to 8; The electrode assembly is located inside the housing, the top cover assembly is fixed to the opening end of the housing, and the electrode assembly is electrically connected to the top cover assembly through electrode tabs.

10. A battery pack, characterized in that, include: Busbar, housing, and battery cell as described in claim 9; The housing forms a receiving cavity, and multiple battery cells are provided, with the multiple battery cells stacked in the receiving cavity; the busbar is connected to the terminals of the multiple battery cells; The upper surface of the boss is bonded to the box body through an adhesive layer.

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