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, an explosion-proof valve and a first insulating part; a first through hole and a second through hole which penetrate through the top cover body are formed in 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 penetrates through the first through hole and is electrically connected with the tab of the battery cell; the anti-explosion valve is mounted in the second through hole and is positioned beside the pole; the first insulating part is arranged on the side, facing the pole lug, of the boss, two limiting plates are arranged on the area, corresponding to the anti-explosion valve, of the first insulating part in a spaced mode, one ends of the two limiting plates are connected with the first insulating part, the other ends of the two limiting plates abut against the pole group, and a limiting space formed between the two limiting plates is used for containing the protruding part of the pole group. The mechanical strength of the battery cell can be improved, the use temperature of the battery cell is controlled, 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 lug 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 structural strength of the battery cell is low. When the battery cell is cooled, heat is only conducted through the pole and the heat conduction layer. The cooling effect is poor. When the battery cell is subjected to external force, the pole group and the top cover body are easily moved relative to each other, causing the pole lug to be pulled and torn, affecting the safety performance of the battery cell. SUMMARY

[0004] The present application provides a top cover assembly, a battery cell and a battery pack to solve the problem that the top cover assembly in the prior art only bears stress through the pole and the pole group and the top cover body are easily moved relative to each other, affecting the safety performance of the battery cell.

[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 lug of the battery cell; an explosion-proof valve installed in the second through hole and located beside the pole; a first insulating part arranged on the side of the boss facing the pole lug, the first insulating part is provided with a limiting plate corresponding to the area of the explosion-proof valve, the limiting plate is provided with two, the two limiting plates are arranged at intervals, one end of the two limiting plates is connected with the first insulating part, the other end is abutted with the pole group, and a limiting space formed between the two limiting plates is used to accommodate the protruding part of the pole group.

[0006] According to the top cover assembly provided by the present application, the limiting plate comprises: an inclined section; one end of the inclined section is connected with the first insulating part, and the other end of the inclined section is abutted with the pole group. The two inclined sections are symmetrically arranged about a plane along the width direction of the top cover body passing through the center of the second through hole, are arranged in a diverging manner from the connection with the first insulating member, and the distance between the two inclined sections gradually increases.

[0007] According to the top cover assembly provided by the application, the limiting plate further comprises a horizontal section. The horizontal section is connected to the other end of the inclined section, is parallel to and abuts against the pole group, and the horizontal section and the inclined section are arranged at an included angle.

[0008] According to the top cover assembly provided by the application, the thickness of the limiting plate is t, and t satisfies t≥0.8 mm. And / or, along the height direction of the top cover body, the assembly gap between the protruding part and the first insulating member is h, and 0.2 mm≤h≤0.5 mm is satisfied.

[0009] According to the top cover assembly provided by the application, the second through hole is a counterbore, the second through hole comprises a counterbore part and a through hole part arranged coaxially, and the counterbore part is arranged in communication with the outer side of the boss.

[0010] According to the top cover assembly provided by the application, the inner wall of the counterbore part is provided with a reinforcing rib. The two ends of the reinforcing rib respectively abut against the side surfaces of the counterbore part along the height direction and the width direction of the top cover body.

[0011] In a second aspect, the application provides a battery cell, comprising a pole group, a shell and a top cover assembly as described above. The pole group is located in the shell, the top cover assembly is fixed to the open end of the shell, and the pole group is electrically connected to the top cover assembly through a tab.

[0012] According to the battery cell provided by the application, the protruding part of the pole group is provided with an exhaust groove on one side of the top cover assembly. The exhaust groove is arranged in extension along the length direction of the top cover body. And / or, the taper of the protruding part of the pole group is θ, and 20°≤θ≤25° is satisfied. The inclination angle of the limiting plate is γ, and γ satisfies γ=θ. And / or, the distance between the outer wall of the protruding part of the pole group and one side of the limiting plate facing the protruding part is A, and 0.7 mm≤A≤1.5 mm is satisfied.

[0013] According to the battery cell provided by the application, along the width direction of the top cover body, the width of the pole group is W1, and the width of the limiting plate is W2, and 3 mm≤W1-W2≤10 mm is satisfied. And / or, along the length direction of the top cover body, the distance between the tab and the limiting plate is W3, which satisfies: W3≥2mm.

[0014] In a third aspect, the present application provides a battery pack, comprising: a busbar, a box body and a battery cell as described above; The box body forms a containing cavity, and the battery cell is provided in plurality, and the plurality of battery cells are stacked in the containing cavity; the busbar is connected with the pole column of the plurality of battery cells; The upper surface of the boss is bonded with the box body through a bonding layer.

[0015] The top cover assembly, the battery cell and the battery pack provided by the present application have the following advantages: the top cover body is bent to form a boss in the area where the explosion-proof valve is located, so that the structural strength of the top cover assembly can be enhanced through the boss, the mechanical strength of the battery cell is improved, the thermal and electrical separation of the pole column and the explosion-proof valve is realized, the surface area of the top cover body is increased through the boss, the heat dissipation area of the top cover body and the bonding area with the heat conduction layer are increased, the heat dissipation efficiency of the battery cell is improved, the use temperature of the battery cell is controlled, two limiting plates are arranged in the area corresponding to the explosion-proof valve of the first insulating piece, the two limiting plates cooperate with the protruding part of the pole group to limit the pole group, which is beneficial to the fixing effect of the pole group, avoids the movement of the pole group and protects the tab, and the safety performance of the battery cell is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a schematic view of the three-dimensional structure of the top cover assembly in the prior art.

[0018] Figure 2 is a schematic view of the three-dimensional structure of the battery pack in the prior art.

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

[0020] Figure 4 is a schematic view of the three-dimensional structure of the top cover assembly in the prior art. Figure 3 is a partial enlarged view of the X part of the top cover assembly in the prior art.

[0021] Figure 5 is a schematic view of the three-dimensional structure of the top cover assembly provided by the present application.

[0022] Figure 6is a front view of the top cover assembly provided by the present application.

[0023] Figure 7 is a top view of the top cover assembly provided by the present application.

[0024] Figure 8 is a perspective structural schematic view of the top cover assembly provided by the present application. Figure 7 is a U-U sectional view of the top cover assembly.

[0025] Figure 9 is a K part local enlarged view of the top cover assembly. Figure 8

[0026] Figure 10 is a perspective structural schematic view of the top cover assembly provided by the present application.

[0027] Figure 11 is a bottom view of the top cover assembly provided by the present application.

[0028] Figure 12 is one of the schematic views of the top cover assembly and pole group assembly provided by the present application.

[0029] Figure 13 is the second schematic view of the top cover assembly and pole group assembly provided by the present application.

[0030] Figure 14 is a local view of the assembly schematic view of the reinforcing rib and counterbore part provided by the present application.

[0031] Figure 15 is the assembly schematic view of the reinforcing rib and second through hole provided by the present application.

[0032] Figure 16 is a perspective structural schematic view of the electric core provided by the present application.

[0033] Figure 17 is a front view of the electric core provided by the present application.

[0034] Reference signs: 1, top cover assembly; 11, top cover body; 12, pole column; 13, explosion-proof valve; 14, first insulating piece; 15, reinforcing rib; 16, limiting plate; 111, first through hole; 112, second through hole; 113, boss; 141, exhaust hole; 151, first side face; 152, second side face; 161, inclined section; 162, horizontal section; 1111, counterbore part; 1112, through hole part; 11121, annular step; 2, pole group; 21, pole lug; 22, protruding part; 221, exhaust groove; 100, busbar; 200, electric core. DETAILED DESCRIPTION

[0035] ​In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the accompanying drawings for the purpose of making the technical solutions in the present application clearer, complete and more comprehensible. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of clarifying the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0038] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0039] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0040] The top cover assembly, the battery cell and the battery pack provided by the embodiments of the present application will be described in detail below in combination with specific embodiments and application scenarios. Figures 1 to 17

[0041] The first aspect, as shown in Figure 5 , Figure 6 and Figure 7 , the present embodiment provides a top cover assembly 1, comprising: a top cover body 11, a pole 12, an explosion-proof valve 13 and a first insulating piece 14.

[0042] The top cover body 11 is formed with a first through hole 111 and a second through hole 112 penetrating the top cover body 11, and the first through hole 111 and the second through hole 112 are arranged at intervals along the length direction 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 protruding towards one side.

[0043] The pole 12 is arranged through the first through hole 111 and is electrically connected with the tab 21 of the battery cell 200.

[0044] The explosion-proof valve 13 is installed in the second through hole 112 and located beside the pole 12.

[0045] The first insulating piece 14 is arranged on the side of the boss 113 facing the tab 21, and the first insulating piece 14 is provided with a limiting plate 16 corresponding to the area of the explosion-proof valve 13. The limiting plate 16 is provided with two limiting plates 16, which are arranged at intervals, one end of the two limiting plates 16 is connected with the first insulating piece 14, and the other end is abutted with the pole group 2. The limiting space formed between the two limiting plates 16 is used to accommodate the protruding part 22 of the pole group 2.

[0046] It can be understood that, as Figures 1 to 4 ​As shown, in the prior art, the pole group 2 of the battery cell 200 is electrically connected to the pole post 12 on the top cover assembly 1 through the pole lug 21, and the top cover assembly 1 is installed at the open end of the shell. The pole post 12 is exposed from both sides of the top cover body 11 through the first through hole 111, one end of the pole post 12 is welded to the pole lug 21 of the battery cell 200, and the other end is used to connect the bar sheet on the busbar 100. When the battery cell 200 is assembled into a battery pack, since all the structures on the top cover body 11 except the pole post 12 are flush with the top cover body 11, the battery cell 200 only contacts other components of the battery pack through the pole post 12.

[0047] The present embodiment sets a boss 113 in the area where the explosion-proof valve 13 is located, so that the space where the explosion-proof valve 13 is located has a protruding structure. When the surface of the battery cell 200 is impacted by external force, the boss 113 can share the external force received by the pole post 12. Moreover, since the boss 113 has a certain structural strength, it can support the top cover body 11, avoiding short circuit of the battery cell 200 and improving the mechanical strength of the whole battery cell.

[0048] At the same time, when the battery cell 200 is stacked to form a battery cell module, the upper surface of the battery cell 200 can not only contact and conduct heat with the heat-conducting layer through the pole post 12 for heat dissipation, but also contact and conduct heat with the heat-conducting layer through the boss 113 for heat dissipation. Compared with the prior art in which most of the area of the top cover body 11 can only dissipate heat through heat radiation, the contact heat conduction effect of the boss 113 of the present embodiment is better, which is more conducive to heat dissipation of the battery cell 200 and control of the use temperature of the battery cell 200, thereby prolonging the service life of the battery cell 200.

[0049] Moreover, since the explosion-proof valve 13 is arranged on the boss 113, the explosion-proof valve 13 and the pole post 12 are at different spatial heights, and the pole post 12 and the explosion-proof valve 13 can be isolated, achieving thermal and electrical separation and improving the safety performance of the battery cell 200.

[0050] In the prior art, in the battery cell 200, in order to provide a bending space for the pole lug 21, a sufficient height needs to be reserved between the pole group 2 and the top cover body 11. As shown in Figure 3 and Figure 4 As shown, the height H of the insulating part 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.

[0051] The present embodiment bends the top cover body 11 to form the boss 113, the boss 113 is a hollow boss, and the accommodation space is towards the side of the pole lug 21, so that the pole lug 21 can be accommodated in the accommodation space, thereby reducing the interval height between the pole group 2 and the top cover body 11 and improving the capacity of the battery cell 200. Moreover, the protruding height of the boss 113 is towards the outside of the top cover body 11, which also fills the space between the pole post 12 and the explosion-proof valve 13, thereby improving the energy density of the battery cell 200.

[0052] In order to isolate the top cover body 11 from the pole column 12 and insulate the pole column 12 and the explosion-proof valve 13, the first insulating piece 14 is arranged on the side of the top cover body 11 facing the tab 21 in the embodiment. The first insulating piece 14 is arranged longitudinally and has a through hole for the pole column 12 to pass through and an exhaust hole 141 for facilitating the exhaust of the explosion-proof valve 13.

[0053] The exhaust hole 141 in the embodiment is provided with a plurality of exhaust holes 141, which are arranged uniformly and form an exhaust channel with the explosion-proof valve 13. When the battery cell 200 is in high-temperature thermal failure, the high-temperature gas can be quickly exhausted to the outside of the battery cell 200, ensuring the safety of the battery cell 200.

[0054] At the same time, in order to limit the displacement of the pole group 2 along the length direction of the top cover body 11, the first insulating piece 14 is provided with a limiting plate 16. The two limiting plates 16 are arranged on the side of the first insulating piece 14 facing the pole group 2 and located in the area corresponding to the explosion-proof valve 13. At the same time, the protruding part 22 is arranged on the part of the pole group 2 between the two limiting plates 16, and the length of the protruding part 22 is less than the distance between the two limiting plates 16. When the pole group 2 is assembled with the top cover assembly 1, the protruding part 22 of the pole group 2 is clamped into the limiting space formed by the two limiting plates 16, and the limiting plates 16 stop the protruding part 22 from both sides, thereby limiting the displacement of the pole group 2 along the length direction of the top cover body 11 and fixing the pole group 2. When the battery cell 200 is subjected to an impact force, the pole group 2 is prevented from moving along the length direction of the top cover body 11 to pull the tab 21, and the limiting plate 16 can also isolate the tab 21 and the pole group 2 to prevent the pole group 2 from being cut, thereby improving the safety performance of the battery cell 200.

[0055] Specifically, the limiting plate 16 can be installed vertically or obliquely with respect to the top cover body 11. The limiting plate 16 can be a strip-shaped plate, an arc-shaped plate, or a broken line plate.

[0056] It should be noted that along the length direction of the top cover body 11, the space where the boss 113 is located between the pole column 12 and the explosion-proof valve 13 is used to accommodate the tab 21. The limiting plate 16 is arranged beside the tab 21 and does not interfere with the tab 21.

[0057] The top cover assembly 1 provided by the application can not only enhance 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 realize thermal-electric separation of the pole column 12 and the explosion-proof valve 13, and increase the surface area of the top cover body 11 through the boss 113, thereby increasing the heat dissipation area of the top cover body 11 and the pasting area with the heat conduction layer, improving the heat dissipation efficiency of the battery cell 200, controlling the use temperature of the battery cell 200, and the two limiting plates 16 are arranged in the area corresponding to the explosion-proof valve 13 of the first insulating piece 14, and the two limiting plates 16 cooperate with the protruding part 22 of the pole group 2 to limit the pole group 2, which is beneficial to the fixing effect of the pole group 2, avoids the movement of the pole group 2 and protects the pole lug 21, and improves the safety performance of the battery cell 200.

[0058] As shown in Figure 6 The limiting plate 16 of the embodiment includes an inclined section 161.

[0059] One end of the inclined section 161 is connected with the first insulating piece 14, and the other end of the inclined section 161 abuts against the pole group 2.

[0060] The two inclined sections 161 are symmetrically arranged about a plane of the top cover body 11 along the width direction passing through the center of the second through hole 112, are arranged in a diverging manner from the connection with the first insulating piece 14, and the distance between the two inclined sections 161 gradually increases.

[0061] It can be understood that, since the distance between the two inclined sections 161 gradually increases, the assembly cross section between the two inclined sections 161 and the protruding part 22 of the pole group 2 also gradually increases, so that when the protruding part 22 of the pole group 2 is installed towards the limiting space, it first passes through a larger cross section and is gradually pushed towards a smaller cross section, which is more conducive to the assembly of the pole group 2 and the first insulating piece 14.

[0062] As shown in Figure 6 The limiting plate 16 of the embodiment further includes a horizontal section 162.

[0063] The horizontal section 162 is connected with the other end of the inclined section 161, abuts against the pole group 2 in parallel, and the horizontal section 162 and the inclined section 161 are arranged at an angle.

[0064] It can be understood that the horizontal section 162 can be installed in close contact with the pole group 2, increases the abutting area of the inclined section 161 and the pole group 2, makes the abutment of the limiting plate 16 and the pole group 2 more stable, and changes the line contact between the limiting plate 16 and the pole group 2 into surface contact, so that the strength of the supporting structure between the pole group 2 and the top cover body 11 is higher.

[0065] As shown in Figure 6 The thickness of the limiting plate 16 of the embodiment is t, and t satisfies t>=0.8mm.

[0066] It can be understood that, in order to ensure the structural strength of the limiting plate 16, the thickness of the limiting plate 16 needs to meet a certain range.

[0067] Specifically, the thickness t of the limiting plate 16 can be 0.8mm, or 0.9mm, or 1.0mm.

[0068] As shown in Figure 17 , along the height direction of the top cover body 11, the assembly gap h between the protruding portion 22 and the first insulating piece 14 of the present embodiment satisfies: 0.2mm≤h≤0.5mm.

[0069] It can be understood that, when assembling the pole group 2 and the top cover assembly 1, in order to ensure the smoothness of the exhaust passage between the pole group 2 and the top cover assembly 1, an assembly gap is reserved between the pole group 2 and the first insulating piece 14, so that the high-temperature gas generated when the battery is in thermal runaway can be discharged to the explosion-proof valve 13 through the exhaust hole 141 of the first insulating piece 14.

[0070] Specifically, h can be 0.2mm, or 0.35mm, or 0.5mm.

[0071] As shown in Figure 7 , Figure 8 , Figure 9 and Figure 15 , the second through hole 112 of the present embodiment is a counterbore hole, and the second through hole 112 includes a counterbore portion 1111 and a through hole portion 1112 coaxially arranged, and the counterbore portion 1111 is in communication with the outside of the boss 113.

[0072] It can be understood that, in order to make the height of the explosion-proof valve 13 sink relative to the top surface of the boss 113, the second through hole 112 of the present embodiment is designed as a counterbore hole. Along the height direction of the top cover body 11, the counterbore portion 1111 and the through hole portion 1112 are sequentially in communication, and the hole diameter of the counterbore portion 1111 is greater than the diameter of the through hole portion 1112. The explosion-proof valve 13 is installed on the inner wall of the through hole portion 1112 and is arranged to extend towards the direction of the pole lug 21. The height of the counterbore portion 1111 is the height of the explosion-proof valve 13 sinking relative to the top surface of the boss 113, and by sinkingly installing the explosion-proof valve 13, the explosion-proof valve 13 and the top surface of the boss 113 are not located in the same plane. When the top surface of the boss 113 is deformed under pressure, the influence on the explosion-proof valve 13 is reduced.

[0073] As shown in Figure 5 and Figure 14 , the inner wall of the counterbore portion 1111 of the present embodiment is provided with a reinforcing rib 15.

[0074] The two ends of the reinforcing rib 15 are respectively in abutment with the side surfaces of the counterbore portion 1111 along the height direction and the width direction of the top cover body 11.

[0075] It can be understood that, further, in order to improve the structural strength of the second through hole 112, the embodiment is provided with the reinforcing rib 15 on the inner wall of the counterbore portion 1111. When the boss 113 is impacted by external force, the reinforcing rib 15 can ensure that the structure of the boss 113 is more stable.

[0076] The two ends of the reinforcing rib 15 are respectively in abutment with the side surfaces of the counterbore portion 1111, thereby improving the structural strength of the two adjacent side walls of the counterbore portion 1111, Specifically, the reinforcing rib 15 can be arranged extending towards the center of the explosion-proof valve 13, or can be arranged inclined relative to the center of the explosion-proof valve 13; the reinforcing rib 15 can be one or multiple.

[0077] Optionally, the cross section of the reinforcing rib 15 can be square, trapezoidal or arc-shaped, so as to achieve optimal mechanical support effect.

[0078] As shown in Figure 5 and Figure 7 , the reinforcing rib 15 of the embodiment is provided with multiple reinforcing ribs 15, which are arranged at intervals along the circumferential side of the counterbore portion 1111.

[0079] The projection width of the reinforcing rib 15 on the top cover body 11 is b, the number of the reinforcing rib 15 is n, and the circumference of the counterbore portion 1111 is C, which satisfy: 0.1≤nb / C≤0.25.

[0080] It can be understood that, in order to improve the structural strength of the boss 113 and prevent stress concentration or deformation of the boss 113 under stress, multiple reinforcing ribs 15 are arranged at intervals on the circumferential side of the counterbore portion 1111. The multiple reinforcing ribs 15 cover the circumferential direction of the counterbore portion 1111, thereby improving the rigidity and bending resistance of the second through hole 112 as a whole, preventing the counterbore portion 1111 from bending or deforming along the circumferential direction, and also improving load distribution, and being easy to process and manufacture.

[0081] In order to reasonably arrange the reinforcing rib 15, the ratio of the sum of the widths of the multiple reinforcing ribs 15 to the circumference of the counterbore portion 1111 needs to satisfy a certain range, so that the structural strength of the counterbore portion 1111 can be strengthened without causing structural redundancy.

[0082] Specifically, nb / C can be 0.1, 0.175 or 0.25.

[0083] As shown in Figure 5 and Figure 14 , along the height direction of the top cover body 11, the projection height of the reinforcing rib 15 of the embodiment on the inner wall of the counterbore portion 1111 is the same as the height of the counterbore portion 1111.

[0084] It can be understood that, in order to make the height of the top surface of the boss 113 consistent, the height of the reinforcing rib 15 of the embodiment is the same as the height of the counterbore part 1111, so that the depth direction of the counterbore part 1111 is strengthened along the height direction of the top cover body 11, and the reinforcing rib 15 does not protrude from the counterbore part 1111 to affect the height of the boss 113.

[0085] As shown in Figure 5 and Figure 14 , the cross section of the reinforcing rib 15 of the embodiment is a triangular structure, which has a first side surface 151 and a second side surface 152 connected, the first side surface 151 is fitted with the side surface of the counterbore part 1111 along the height direction of the top cover body 11, and the second side surface 152 is fitted with the side surface of the counterbore part 1111 along the width direction of the top cover body 11.

[0086] It can be understood that, based on the stability of the triangular structure, the triangular structure can enhance the rigidity and anti-deformation ability, and effectively disperse and transfer external forces acting on the counterbore part 1111 through the truss structure of the triangle. And the first side surface 151 and the second side surface 152 of the triangular structure act as a ribbed structure, providing additional support for the side surface of the counterbore part 1111 and improving the strength and carrying capacity.

[0087] As shown in Figure 7 , Figure 8 , Figure 9 and , along the height direction of the top cover body 11, the depth of the counterbore part 1111 of the embodiment is H2, and the thickness of the top wall of the boss 113 is T2, which satisfies: 1.5mm≤H2≤3mm, H2 / T2≤2.

[0088] It can be understood that, for the processing of the counterbore part 1111, a stamping structure can be used. Due to the limitation of the stamping process, the depth of the counterbore part 1111 needs to meet a certain range to facilitate processing. And the counterbore part 1111 is formed on the top surface of the boss 113, and the ratio of the height of the counterbore part 1111 to the thickness of the top wall of the boss 113 needs to meet a certain range.

[0089] Specifically, H2 can be 1.5mm, 2.25mm or 3mm. H2 / T2 can be 2, 1.5 or 1.

[0090] As shown in Figure 7 , Figure 8 , Figure 9 and Figure 15As shown, the inner wall of the through hole 1112 in this embodiment has an annular step 11121. The explosion-proof valve 13 is installed on the side of the annular step 11121 facing the countersunk hole 1111. The height of the annular step 11121 is H3, and H3 satisfies: H3≥1.2mm.

[0091] Understandably, to facilitate the installation of the explosion-proof valve 13 in the recessed hole, this embodiment provides an annular step 11121 in the through hole portion 1112. The explosion-proof valve 13 can be circumferentially welded to the step surface of the annular step 11121, thereby improving the connection strength between the explosion-proof valve 13 and the through hole portion 1112. Furthermore, since the annular step 11121 forms a circumferentially reinforced structure, it improves the structural strength of the through hole portion 1112 and avoids deformation and bending of the through hole portion 1112.

[0092] Specifically, H3 can be 1.2mm, 1.3mm, or 1.4mm.

[0093] like Figure 17 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°.

[0094] 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.

[0095] Specifically, the taper β of the truncated cone can be 20°, 22.5°, or 25°.

[0096] like Figure 17 As shown, in this embodiment, the boss 113 and the top cover body 11 are integrally formed.

[0097] 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.

[0098] Alternatively, the one-piece molding structure can be achieved by stamping, stretching, or embossing.

[0099] 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.

[0100] like Figure 5 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.

[0101] The boss 113 is arranged between the two polar posts 12, and the second through hole 112 is arranged in the middle of the boss 113.

[0102] It can be understood that the top cover body 11 of the embodiment is provided with two polar posts 12, one of which is a positive polar post, and the other is a negative polar post. Along the length direction of the top cover body 11, the negative polar post and the positive polar post are arranged at two ends of the top cover body 11, and the negative polar post and the positive polar post are connected with the polar group 2 of the battery cell 200 respectively.

[0103] An explosion-proof valve 13 is arranged between the positive polar post and the negative polar post, and a boss 113 is formed between the positive polar post and the negative polar post, so as to ensure that the boss 113 disperses the pressure between the positive polar post and the negative polar post, improves the structural strength of the top cover assembly 1, and ensures the safety of the battery cell 200.

[0104] In addition, the explosion-proof valve 13 is arranged in the middle of the boss 113, and the distance between the positive polar post and the negative polar post is equal, so that the structure of the top cover body 11 is relatively regular, easy to process and manufacture, and can effectively isolate the explosion-proof valve 13 and the positive polar post and the negative polar post.

[0105] As shown in Figure 7 , Figure 8 and Figure 9 , along the height direction of the top cover body 11, the height of the boss 113 is H1, the thickness of the top cover body 11 is T1, and the thickness of the top wall of the boss 113 is T2, which satisfy: T1≥2mm, 0.75≤T2 / T1≤1.1, 2≤H1 / T1≤2.75.

[0106] It can be understood that in order to ensure the structural strength of the boss 113, the thickness of the top cover body 11, the ratio of the thickness of the top wall of the boss 113 to the thickness of the top cover body 11, and the ratio of the height of the boss 113 to the thickness of the top cover body 11 need to satisfy a certain range, so as to ensure the supporting strength and structural strength of the boss 113.

[0107] Specifically, T1 can be 2mm, 2.5mm or 3mm; T2 / T1 can be 0.75, 0.925 or 1.1; H1 / T1 can be 2, 2.375 or 2.75.

[0108] As shown in Figure 7 , along the length direction of the top cover body 11, the distance between the bending part of the boss 113 and the polar post 12 of the embodiment is a, which satisfies: a≥2.5mm.

[0109] It can be understood that the bending part of the boss 113 needs to be spaced apart from the polar post 12 by a certain distance, so as to avoid collision between the boss 113 and the polar post 12 when the boss 113 is stressed, and damage to the polar post 12.

[0110] Specifically, a can be 2.5 mm, can also be 3 mm, and can also be 3.5 mm.

[0111] As shown in the drawings, the length of the top cover body 11 is L, and L satisfies: 150 mm≤L≤300 mm. Figure 7

[0112] The width of the top cover body 11 is W, and W satisfies: 25 mm≤W≤75 mm.

[0113] It can be understood that the length and width of the top cover body 11 of the embodiment are limited, which can adapt to the assembly requirements of different capacities of the battery cell 200, and at the same time avoid material redundancy or structural deformation caused by being too long.

[0114] Specifically, the length L of the top cover body 11 can be 150 mm, can also be 225 mm, and can also be 300 mm. The width W of the top cover body 11 can be 25 mm, can also be 50 mm, and can also be 75 mm.

[0115] A second aspect, as shown in the drawings, the embodiment provides a battery cell 200, comprising: a pole group 2, a shell and a top cover assembly 1 as above. Figure 16

[0116] The pole group 2 is located in the shell, and the top cover assembly 1 is fixed to the open end of the shell. The pole group 2 is electrically connected to the top cover assembly 1 through the tab 21.

[0117] Specifically, since the battery cell 200 comprises the top cover assembly 1, the specific structure of the top cover assembly 1 refers to the above-mentioned embodiments, and the battery cell 200 shown in the embodiment comprises all the technical solutions of the above-mentioned embodiments. Therefore, at least all the beneficial effects obtained by all the technical solutions of the above-mentioned embodiments are obtained, which will not be described one by one.

[0118] It can be understood that the pole group 2 is loaded into the shell, and the top cover assembly 1 is arranged at the open end of the shell. The pole group 2 is electrically connected to the pole 12 of the top cover assembly 1 through the tab 21 to realize the transmission of current. Since the top cover assembly 1 is bent to form the boss 113 in the area where the explosion-proof valve 13 of the top cover body 11 is located, the contact heat dissipation area of the upper surface of the top cover body 11 is improved, which is beneficial to control the working problem of the battery cell 200, prolong the service life of the battery cell 200, and improve the stress area of the top cover body 11, avoid the single stress of the pole 12, improve the safety performance of the battery cell 200, and two limiting plates 16 are arranged in the area corresponding to the explosion-proof valve 13 of the first insulating piece 14. The two limiting plates 16 cooperate with the protruding part 22 of the pole group 2 to limit the pole group 2, which is beneficial to the fixing effect of the pole group 2, avoids the movement of the pole group 2 and protects the tab 21, and improves the safety performance of the battery cell 200.

[0119] As​​Figure 12 and Figure 13 As shown in FIG. 1, FIG. 2 and FIG. 3, the assembling process of the pole group 2 and the top cover assembly 1 is described with the example that the top cover assembly 1 has two pole posts 12. First, the pole group 2 and the pole lug 21 are in a flattened state, the two pole groups 2 are respectively placed on the two sides of the top cover body 11 along the width direction of the top cover body 11, the two pole lugs 21 are respectively aligned with the two pole posts 12, and the pole lug 21 is welded with the pole post 12. Then, the two pole groups 2 are turned 90° towards the direction away from the top cover assembly 1, so that the top cover assembly 1 is located at the side of the pole group 2. Finally, the pole group 2 is assembled into the shell, and the top cover assembly 1 is located at the opening end of the shell.

[0120] As shown in FIG. 4, the protruding part 22 of the pole group 2 of the present embodiment is provided with an exhaust groove 221 towards one side of the top cover assembly 1; the exhaust groove 221 is provided along the length direction of the top cover body 11. Figure 10 As can be understood, in order to ensure the smoothness of the exhaust passage of the explosion-proof valve 13, the protruding part 22 of the pole group 2 of the present embodiment is provided with the exhaust groove 221, which is provided in communication with the exhaust hole 141 of the first insulating piece 14, so that the high-temperature gas has enough space to flow until it flows to the explosion-proof valve 13. Further, since the exhaust groove 221 is provided along the length direction of the top cover body 11, the high-temperature gas of other parts of the pole group 2 can also enter the exhaust groove 221 from the two sides of the protruding part 22, which is conducive to the flow of the high-temperature gas.

[0121] As shown in FIG. 5, the taper of the protruding part 22 of the pole group 2 of the present embodiment is θ, and θ satisfies: 20°≤θ≤25°.

[0122] Figure 17 As can be understood, in order to ensure the assembly effect of the pole group 2 and the top cover assembly 1, the taper of the protruding part 22 of the pole group 2 is consistent with the inclination angle of the limiting plate 16. When the pole group 2 moves due to external force, the protruding part 22 can completely fit with the limiting plate 16, which can better stop the pole group 2 and strengthen the limiting effect of the pole group 2.

[0123] Specifically, the taper θ of the protruding part 22 can be 20°, 22.5° or 25°. The inclination angle γ of the limiting plate 16 can be 20°, 22.5° or 25°.

[0124] As shown in FIG. 6, the distance A between the outer wall of the protruding part 22 of the pole group 2 and the side of the limiting plate 16 towards the protruding part 22 satisfies: 0.7mm≤A≤1.5mm.

[0125] As can be understood, in order to ensure the assembly effect of the pole group 2 and the top cover assembly 1, the taper of the protruding part 22 of the pole group 2 is consistent with the inclination angle of the limiting plate 16. When the pole group 2 moves due to external force, the protruding part 22 can completely fit with the limiting plate 16, which can better stop the pole group 2 and strengthen the limiting effect of the pole group 2.

[0126] As shown in FIG. 6, the distance A between the outer wall of the protruding part 22 of the pole group 2 and the side of the limiting plate 16 towards the protruding part 22 satisfies: 0.7mm≤A≤1.5mm. Figure 17 As can be understood, in order to ensure the assembly effect of the pole group 2 and the top cover assembly 1, the taper of the protruding part 22 of the pole group 2 is consistent with the inclination angle of the limiting plate 16. When the pole group 2 moves due to external force, the protruding part 22 can completely fit with the limiting plate 16, which can better stop the pole group 2 and strengthen the limiting effect of the pole group 2.​

[0127] It can be understood that the distance between the protruding portion 22 of the pole group 2 and the limiting plate 16 needs to meet a certain range, so as to avoid that the distance is too large and the limiting effect of the pole group 2 is not obvious, or the distance is too small and the limiting plate 16 interferes with the pole group 2.

[0128] Specifically, A can be 0.7 mm, can also be 1.1 mm, and can also be 1.5 mm.

[0129] As shown in Figure 11 and Figure 16 , along the width direction of the top cover body 11, the width of the pole group 2 is W1, and the width of the limiting plate 16 is W2, which satisfies: 3mm≤W1-W2≤10mm.

[0130] It can be understood that, in order to ensure the beauty of the pole group 2 after being installed with the top cover assembly 1, the width of the limiting plate 16 is smaller than the width of the pole group 2, and the width of the limiting plate 16 needs to be as close to the width of the pole group 2 as possible, thereby facilitating the limiting effect of the limiting plate 16 on the pole group 2.

[0131] Specifically, W1-W2 can be 3mm, can also be 6.5mm, and can also be 10mm.

[0132] As shown in Figure 13 and Figure 17 , along the length direction of the top cover body 11, the distance between the tab 21 and the limiting plate 16 of the present embodiment is W3, which satisfies: W3≥2mm.

[0133] It can be understood that after the welding of the tab 21 and the pole 12 is completed, the distance between the tab 21 and the limiting plate 16 needs to meet a certain range, so as to avoid that the limiting plate 16 interferes with the tab 21 and affects the normal operation of the battery cell 200.

[0134] Specifically, W3 can be 2mm, can also be 2.5mm, and can also be 3mm.

[0135] As shown in Table 1 and Table , the production line of the present embodiment tests each index of the top cover assembly 1 to verify the technical effect of different data. In turn, the width W1 of the pole group 2, the width W2 of the limiting plate 16, the distance W3 between the tab 21 and the limiting plate 16, the thickness t of the limiting plate 16, the taper θ of the protruding portion 22 of the pole group 2, the inclination angle γ of the limiting plate 16, the difference W1-W2 between the width of the pole group 2 and the width of the limiting plate 16, and the distance A between the outer wall of the protruding portion 22 of the pole group 2 and the side of the limiting plate 16 facing the protruding portion 22 are changed to simulate and analyze the battery cell 200.

[0136] It can be seen that when the structure design of the top cover assembly 1 meets the above requirements, the structural strength of the first insulating piece 14 meets the requirements and there is no interference problem with the pole group 2.

[0137] Table 1

[0138] Table 2

[0139] In a third aspect, the embodiment provides a battery pack, comprising: a busbar 100, a box body, and the above-mentioned battery cell 200.

[0140] The box body forms a containing cavity, the battery cell 200 is provided in plurality, and the plurality of battery cells 200 are stacked and arranged in the containing cavity; the busbar 100 is connected with the pole 12 of the plurality of battery cells 200, and the upper surface of the boss 113 is bonded with the box body through the adhesive layer.

[0141] Specifically, since the battery pack comprises the battery cell 200, the specific structure of the battery cell 200 refers to the above-mentioned embodiment, the battery pack shown in the embodiment comprises all the technical solutions of the above-mentioned embodiments, therefore, at least has all the beneficial effects obtained by all the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0142] It can be understood that after the battery cell 200 is arranged in groups in the containing cavity, the pole 12 of each battery cell 200 is welded with the gasket on the busbar 100, the busbar 100 connects the stacked battery cells 200 into groups, and the gasket is fixedly connected with the box body through the heat-conducting layer. Since the boss 113 is arranged on the top cover body 11 at the area where the explosion-proof valve 13 is located, the adhesive layer is arranged on the top surface of the boss 113, and the boss 113 is fixedly adhered after abutting against the box body, so that the boss 113 can conduct heat through direct contact with the box body. Since the first insulating piece 14 is provided with the limiting plate 16, the displacement amount of the pole group 2 can be limited, the fixing effect of the pole group 2 is improved, and thus the safety performance of the battery cell 200 is improved.

[0143] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A top cover assembly, applied to a battery cell, characterized in that, The top cover body is formed with a first through hole and a second through hole penetrating through the top cover body, the first through hole and the second through hole are arranged at intervals along the length direction of the top cover body, and the top cover body is bent to form a boss protruding towards one side in the area where the second through hole is located. The pole post is arranged in the first through hole and is electrically connected with the tab of the battery cell. The explosion-proof valve is arranged in the second through hole and is located beside the pole post. The first insulating piece is arranged on the side of the boss facing the tab, the first insulating piece is provided with a limiting plate corresponding to the area of the explosion-proof valve, the limiting plate is provided with two limiting plates arranged at intervals, one end of the two limiting plates is connected with the first insulating piece, the other end is arranged against the pole group, and a limiting space formed between the two limiting plates is used for accommodating the protruding part of the pole group. The limiting plate comprises an inclined section.

2. The roof assembly of claim 1, wherein, One end of the inclined section is connected with the first insulating piece, and the other end of the inclined section is arranged against the pole group. The two inclined sections are symmetrically arranged about a plane of the top cover body passing through the center of the second through hole, are arranged in a diverging manner from the connection with the first insulating piece, and the distance between the two inclined sections gradually increases. The limiting plate further comprises a horizontal section.

3. The roof assembly of claim 2, wherein, The horizontal section is connected with the other end of the inclined section, is arranged in parallel to and against the pole group, and the horizontal section and the inclined section are arranged at an included angle. The thickness of the limiting plate is t, and t satisfies t>=0.8mm.

4. The roof assembly of claim 1, wherein, And / or, along the height direction of the top cover body, the assembly gap between the protruding part and the first insulating piece is h, and 0.2mm<=h<=0.5mm is satisfied. The second through hole is a counterbore, and the second through hole comprises a counterbore part and a through hole part arranged coaxially, and the counterbore part is arranged in communication with the outside of the boss.

5. The roof assembly of claim 1, wherein, The inner wall of the counterbore part is provided with a reinforcing rib.

6. The roof assembly of claim 5, wherein, The two ends of the reinforcing rib are arranged against the side surfaces of the counterbore part along the height direction and the width direction of the top cover body, respectively. The top cover assembly comprises:

7. An electric cell characterized by The pole group, the shell and the top cover assembly as claimed in any one of claims 1 to 6; The pole group is located in the shell, the top cover assembly is fixed to the open end of the shell, and the pole group is electrically connected with the top cover assembly through the tab. The protruding part of the pole group is provided with an exhaust groove on the side facing the top cover assembly; 8. The electric cell of claim 7, wherein, The exhaust groove is arranged in extension along the length direction of the top cover body; And / or, the taper of the protruding part of the pole group is θ, and θ satisfies 20<=θ<=25; The inclination angle of the limiting plate is γ, and γ satisfies γ=θ; And / or, the distance between the outer wall of the protruding part of the pole group and the side of the limiting plate facing the protruding part is A, and 0.7<=A<=1.5mm is satisfied. Along the width direction of the top cover body, the width of the pole group is W1, and the width of the limiting plate is W2, and 3<=W1-W2<=10mm is satisfied.

9. The electric cell of claim 7, wherein, And / or, along the length direction of the top cover body, the distance between the tab and the limiting plate is W3, and W3>=2mm is satisfied. The bus bar, the box body and the battery cell as claimed in any one of claims 7 to 9; 10. A battery pack, characterized by, ​ ​ The box forms a containing cavity, the battery cells are provided in plurality, and the plurality of battery cells are stacked in the containing cavity; the bus bars are connected with the pole columns of the plurality of battery cells; The upper surface of the boss is bonded with the box through a bonding layer.

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