Cover plate assembly and cylindrical lithium battery

Abstract

The application provides a cover plate assembly and a cylindrical lithium battery. The cover plate assembly comprises a cover plate, an upper plastic part and a pole. The upper plastic part comprises a body and a flange. On the edge of the first mounting hole opening, the cover plate is alternately provided with a first boss and a first groove which are adjacent to each other on the top surface. On the edge of the outer wall surface of the flange, the body is alternately provided with a second boss and a second groove which are adjacent to each other on the bottom surface. After the cover plate and the upper plastic part are assembled, the first boss, the first groove, the second boss and the second groove jointly form an anti-twist structure. Due to the limiting effect of the anti-twist structure, the upper plastic part and the cover plate cannot rotate relative to each other. Therefore, the lithium battery comprising the cover plate assembly can avoid the upper plastic part twisting relative to the cover plate after long-time use or under harsh working conditions, can avoid the pole twisting, and can improve the reliability of the lithium battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, and particularly relates to a cover plate assembly and a cylindrical lithium battery. BACKGROUND

[0002] In the related art, a positive pole riveting structure is constructed on a top cover as a positive pole of a cylindrical lithium battery, which generally comprises a pole made of a metal material and an upper plastic piece made of a plastic material. The sealing and fixing of the pole are achieved by the riveting force between the flange of the pole and the upper plastic piece. However, since the hardness and strength of the upper plastic piece are far less than those of the pole, if the pole frequently shakes during long-term use, the upper plastic piece will be deformed, and then the upper plastic piece will be loosened and twisted. If the pole is twisted together with the upper plastic piece, the lithium battery will be disabled. This problem is particularly prominent for lithium batteries used in harsh working conditions such as electric tools. SUMMARY

[0003] Embodiments of the present application provide a cover plate assembly and a cylindrical lithium battery to at least solve the technical problem that the upper plastic piece in the existing cover plate assembly is prone to twisting during long-term use and in harsh working conditions.

[0004] The first aspect of the present application provides a cover plate assembly, comprising:

[0005] a cover plate provided with a first mounting hole penetrating therethrough, the first mounting hole being circular, and a circle of first bosses and first grooves alternately arranged and adjacent to each other along the edge of the first mounting hole opening on the top surface of the cover plate;

[0006] an upper plastic piece comprising a body and a flange provided at the bottom of the body, the flange being cylindrical, the upper plastic piece being provided with a second mounting hole penetrating the body and the flange, the body abutting against the top surface of the cover plate, and the flange penetrating the first mounting hole, a circle of second bosses and second grooves alternately arranged and adjacent to each other along the outer periphery of the flange;

[0007] a pole penetrating the second mounting hole;

[0008] wherein each of the first bosses is one-to-one correspondingly nested in each of the second grooves, and each of the second bosses is one-to-one correspondingly nested in each of the first grooves, so as to limit the rotation of the upper plastic piece relative to the cover plate.

[0009] The cover plate assembly according to the embodiments of the present application has at least the following beneficial effects:

[0010] The cover plate assembly of the embodiment of the present application, the pole is riveted and pressed on the top surface of the cover plate through a riveting process, the first boss and the first groove of the cover plate and the second boss and the second groove of the upper plastic part constitute a torsion prevention structure, due to the limiting effect of the torsion prevention structure, the upper plastic part and the cover plate cannot rotate relative to each other, thereby, the lithium battery comprising the cover plate assembly can avoid the torsion of the upper plastic part relative to the cover plate after long-term use or under harsh working conditions, and can further avoid the torsion of the pole, thereby improving the reliability of the lithium battery.

[0011] In a possible implementation, a chamfer is arranged between the top surface of the first boss and the hole wall of the first mounting hole, and the chamfer comprises a first chamfer and a second chamfer which are connected and have different inclination angles. By arranging the first chamfer and the second chamfer which have different inclination angles, the upper plastic part can be continuously positioned and guided by the first chamfer and the second chamfer during assembly, and the connection with the cover plate can be quickly and accurately achieved.

[0012] In a possible implementation, the thickness of the cover plate at the position where the first boss is arranged is H, the vertical height of the first chamfer along the thickness direction of the cover plate is H1, and the vertical height of the second chamfer along the thickness direction of the cover plate is H2, and H1 / H = 10% to 30% and H2 / H = 20% to 40% are satisfied. By reasonably arranging the vertical heights of the first chamfer and the second chamfer, the first chamfer and the second chamfer can effectively position and guide the upper plastic part, and at the same time, the hole wall of the first mounting hole has sufficient size, so that the upper plastic part is well fitted with the hole wall, to ensure sufficient torsion effect, thereby improving the reliability of the connection between the upper plastic part and the cover plate.

[0013] In a possible implementation, the bottom edge of the second chamfer is coplanar with the top surface of the first groove. Thus, the hole wall of the first mounting hole for fitting with the upper plastic part extends from the top surface of the first groove to the bottom surface of the cover plate, and the height and shape of the hole wall along the circumferential direction are consistent, and the hole wall can be well fitted with the upper plastic part.

[0014] In a possible implementation, the included angle between the first chamfer and the hole wall is α, and 35°≤α≤60° is satisfied, and the included angle between the second chamfer and the hole wall is β, and 10°≤β≤30° is satisfied. By reasonably designing the included angles between the first chamfer, the second chamfer and the hole wall, the positioning and guiding effect of the upper plastic part can be effectively achieved, and the assembly efficiency can be improved.

[0015] In a possible implementation, the first protrusions and the first grooves are in circular arc shapes, the first protrusions and the first grooves are alternately connected around the first mounting hole to form a circular ring structure, the central angle of the first protrusions is R1, the central angle of the first grooves is R2, and R2 < R1 is satisfied. For the anti-torsion structure, the anti-torsion is mainly achieved by cooperation of the first protrusions of the cover plate and the second grooves of the upper plastic part, the second protrusions of the upper plastic part play an auxiliary anti-torsion role, the material of the cover plate is metal, and the material of the upper plastic part is plastic. The strength of the metal material is much greater than that of the plastic material, and therefore, by designing the central angle R2 of the first grooves to be smaller than the central angle R1 of the first protrusions, the strength of the first protrusion structure can be significantly increased, and the anti-torsion effect can be improved.

[0016] In a possible implementation, R2 / R1 = 60% to 80%. By reasonably designing the central angles of the first protrusions and the first grooves, the first protrusions and the second protrusions can have good strength, and the anti-torsion strength can be improved.

[0017] In a possible implementation, the thickness of the cover plate is H0, the depth of the first grooves is H3, and H3 / H0 = 30% to 50% is satisfied. By reasonably designing the depth of the first grooves, the anti-torsion effect can be ensured, and the structural strength of the cover plate at the first mounting hole can also be ensured.

[0018] In a possible implementation, the thickness of the cover plate is H0, the height of the first protrusions beyond the top surface of the first grooves is H4, and H4 / H0 = 70% to 95% is satisfied. By reasonably designing the height of the first protrusions, the anti-torsion effect can be ensured, and the structural strength of the upper plastic part can also be ensured.

[0019] The second aspect embodiment of the application provides a cylindrical lithium battery, which includes the cover plate assembly of the first aspect embodiment. The cover plate assembly of the application is suitable for 46 series cylindrical lithium batteries, for example, can be 4680, 4690, 4695, 46120, and the like.

[0020] According to the cylindrical lithium battery of the application, at least the following beneficial effects are achieved:

[0021] The cylindrical lithium battery of the application is not prone to torsion of the upper plastic part relative to the cover plate during long-time use or use in harsh conditions, thereby ensuring the connection stability between the cover plate and the upper plastic part, further ensuring the stability of the riveting of the pole post flange, and further preventing the pole post from being prone to torsion, and having the characteristic of high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 is a sectional view of a cover plate assembly provided by an embodiment of the present application;

[0024] Figure 2 is a sectional view of a cover plate assembly provided by an embodiment of the present application, in another angle and partially enlarged;

[0025] Figure 3 is a sectional view of a cover plate in a cover plate assembly provided by an embodiment of the present application;

[0026] Figure 4 is a sectional view of a cover plate in a cover plate assembly provided by an embodiment of the present application; Figure 3 is a partial view of A in FIG. 1;

[0027] Figure 5 is a sectional view of a cover plate in a cover plate assembly provided by an embodiment of the present application; Figure 3 is a top view of a cover plate in a cover plate assembly provided by an embodiment of the present application;

[0028] Figure 6 is a structural view of an upper plastic part in a cover plate assembly provided by an embodiment of the present application.

[0029] Reference signs:

[0030] 10-cover plate, 11-first mounting hole, 12-first boss, 121-chamfered part, 1211-first chamfered part, 1212-second chamfered part, 13-first recess, 14-hole wall;

[0031] 20-upper plastic part, 21-body, 211-second boss, 212-second recess, 22-flange, 23-second mounting hole;

[0032] 30-pole, 31-flange;

[0033] 40-housing;

[0034] 50-lower plastic part;

[0035] 60-sealing ring. DETAILED DESCRIPTION

[0036] Embodiments of the present embodiment will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present embodiment and cannot be understood as a limitation of the present embodiment.

[0037] In the description of the present embodiment, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, which is only for the purpose of facilitating the description of the present embodiment and simplifying the description, and does 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 of the present embodiment.

[0038] In the description of the present embodiment, the meaning of several is one or more, and the meaning of multiple is more than two. Greater than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of indicated technical features.

[0039] In the description of the present embodiment, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the above words in the present embodiment in combination with the specific content of the technical solution.

[0040] The following will be described in detail Figures 1 to 6 The cover plate assembly of the embodiments of the present application is described in detail.

[0041] As shown in Figure 1 and Figure 2 The cover plate assembly includes a cover plate 10, an upper plastic part 20, and a pole 30. The cover plate assembly can be used for various types of lithium batteries, such as cylindrical lithium batteries, to form the positive or negative electrode of the lithium battery. The cover plate assembly of the embodiments of the present application forms a torsion prevention structure by constructing a first boss 12 and a first groove 13 on the cover plate 10, and a second boss 211 and a second groove 212 on the upper plastic part 20. After assembly, the first boss 12, the first groove 13, the second boss 211, and the second groove 212 are combined to form a torsion prevention structure, which can effectively prevent the upper plastic part 20 from rotating relative to the cover plate 10, thereby improving the reliability of the lithium battery.

[0042] The cover plate assembly includes a cover plate 10, which is made of metal. It can be understood that the cover plate 10 is the mounting basis of the upper plastic part 20, the pole 30, etc. and is connected to the shell of the lithium battery when the cover plate assembly is assembled into a lithium battery. As shown inFigure 1 and Figure 3 As shown, taking the application of a cover plate assembly in a cylindrical lithium battery as an example, the cylindrical lithium battery includes a cylindrical housing 40, and a cover plate 10, serving as the top cover of the cylindrical lithium battery, is located on top of the housing 40, and the cover plate 10 is integrally formed with the housing 40. This eliminates the need for separately welding the cover plate 10 to the housing 40, saving processes and costs. However, this is not a limitation; the cover plate 10 can also be a separate component, such as a metal sheet, which is subsequently welded to the housing 40. Furthermore, since the cover plate 10 is the top cover of the cylindrical lithium battery, the cover plate 10 is generally circular; however, it is not limited to this. For example, the cover plate 10 can also be rectangular for use with prismatic lithium batteries.

[0043] like Figure 3 As shown, it can be understood that the cover plate 10 has opposing top and bottom surfaces. For the lithium battery, the top surface of the cover plate 10 is located outside the lithium battery, and the bottom surface of the cover plate 10 is located inside the lithium battery. The cover plate 10 is provided with a through-hole 11 in a circular shape (see reference). Figures 3 to 5 That is, the first mounting hole 11 penetrates the cover plate 10 along the thickness direction (up and down direction in the figure), so that the first mounting hole 11 connects the top surface and the bottom surface of the cover plate 10. The first mounting hole 11 is used for the upper plastic part 20 to pass through it, so as to achieve insulation and isolation of the pole post 30 passing through the upper plastic part 20.

[0044] It can be understood that, for example Figure 3 As shown, along the edge of the opening of the first mounting hole 11 on one side of the top surface of the cover plate 10, alternating first bosses 12 and first grooves 13 are provided. It can be understood that by constructing the first bosses 12 and first grooves 13 on the top surface of the cover plate 10 along the edge of the opening of the first mounting hole 11, the first bosses 12 and first grooves 13 can be nested with the second grooves 212 and second bosses 211 constructed on the upper plastic part 20, which will be described below, during operation, when the plastic part 20 is assembled in a downward direction towards the top surface of the cover plate 10, ultimately forming an anti-torsion structure.

[0045] It is understood that the alternating arrangement described here refers to the staggered arrangement of the first boss 12 and the first groove 13 in an alternating manner along the circumferential direction surrounding the edge of the opening of the first mounting hole 11. That is, a first groove 13 is provided between two first bosses 12, and correspondingly, a first boss 12 is provided between two first grooves 13. In this way, firstly, in the circumferential direction surrounding the first mounting hole 11, staggered first bosses 12 and first grooves 13 are formed, so that the anti-torsion structure formed after nesting with the second groove 212 and the second boss 211 is evenly distributed in a 360-degree circumferential range, the force is more balanced, and the anti-torsion structure is safe and reliable.

[0046] In addition, it can be understood that the abutment described herein refers to that there is no isolation between the first protrusions 12 and the first grooves 13, that is, the space formed between the two first protrusions 12 is the first groove 13, and correspondingly, the structure in which the two first grooves 13 are spaced apart is the first protrusion 12.

[0047] As shown in FIG. 1, the first protrusions 12 and the first grooves 13 are arranged on the top surface of the cover plate 10, and the second protrusions 211 and the second grooves 212 are arranged on the bottom surface of the upper plastic part 20. Figure 5 As shown in FIG. 1, the first protrusions 12 and the first grooves 13 are arranged on the top surface of the cover plate 10, and the second protrusions 211 and the second grooves 212 are arranged on the bottom surface of the upper plastic part 20. Figure 6 It can be understood that the anti-twist structure described in the embodiment is composed of the first protrusions 12 and the first grooves 13 arranged on the cover plate 10, and the second protrusions 211 and the second grooves 212 arranged on the upper plastic part 20. Therefore, the shapes, sizes and numbers of the first protrusions 12 and the second grooves 212 are matched, and the shapes, sizes and numbers of the first grooves 13 and the second protrusions 211 are matched. Specifically, the height of the first protrusion 12 is matched with the depth of the second groove 212, so that the first protrusion 12 can be completely nested in the second groove 212. Correspondingly, the height of the second protrusion 211 is matched with the depth of the first groove 13, so that the second protrusion 211 can be completely nested in the first groove 13, thereby enabling the bottom surface of the upper plastic part 20 to be well fitted with the top surface of the cover plate 10. Taking the numbers of the first protrusions 12, the first grooves 13, the second protrusions 211 and the second grooves 212 as examples, for example, the number of the first protrusions 12 and the number of the first grooves 13 are both four, and correspondingly, the number of the second protrusions 211 and the number of the second grooves 212 on the upper plastic part 20 matched therewith are also four.

[0048] It can be understood that when the upper plastic part 20 is correctly installed to the cover plate 10 and is arranged in the first mounting hole 11, each first protrusion 12 is one-to-one correspondingly nested in each second groove 212, and each second protrusion 211 is one-to-one correspondingly nested in each first groove 13. The anti-twist structure composed of the first protrusions 12, the first grooves 13, the second protrusions 211 and the second grooves 212 has a limiting effect, so that the upper plastic part 20 and the cover plate 10 cannot rotate relative to each other.

[0049] As shown in FIG. 1, the first protrusions 12 and the first grooves 13 are arranged on the top surface of the cover plate 10, and the second protrusions 211 and the second grooves 212 are arranged on the bottom surface of the upper plastic part 20. Figure 1 and Figure 2 As shown in FIG. 1, the first protrusions 12 and the first grooves 13 are arranged on the top surface of the cover plate 10, and the second protrusions 211 and the second grooves 212 are arranged on the bottom surface of the upper plastic part 20. Figure 2 , Figure 3 and Figure 4As shown, a chamfer portion 121 is arranged between the top surface of the first boss 12 and the hole wall 14 of the first mounting hole 11, and the chamfer portion 121 comprises a first chamfer portion 1211 and a second chamfer portion 1212 which are connected and have different inclination angles. It can be understood that in this way, the top surface of the first boss 12, the first chamfer portion 1211, the second chamfer portion 1212 and the hole wall 14 are sequentially and continuously connected. By arranging the first chamfer portion 1211 and the second chamfer portion 1212 which have different inclination angles, when the upper plastic part 20 is assembled in the direction from top to bottom and in the direction close to the top surface of the cover plate 10, the flange 22 of the upper plastic part 20 can be continuously positioned and guided by the first chamfer portion 1211 and the second chamfer portion 1212, and quickly and accurately inserted into the first mounting hole 11, and the outer wall surface thereof is well fitted with the hole wall 14 of the first mounting hole 11.

[0050] Further, as shown in Figure 4 The thickness of the cover plate 10 at the position where the first boss 12 is arranged is H, the vertical height (up-down direction height) of the first chamfer portion 1211 along the thickness direction of the cover plate 10 is H1, and the vertical height of the second chamfer portion 1212 along the thickness direction of the cover plate 10 is H2, and H1 / H=10%~30% and H2 / H=20%~40% are satisfied. Since the thickness of the cover plate 10 is usually thin, by reasonably arranging the vertical heights of the first chamfer portion 1211 and the second chamfer portion 1212, the hole wall 14 of the first mounting hole 11 has sufficient size while ensuring that the first chamfer portion 1211 and the second chamfer portion 1212 can effectively position and guide the flange 22 of the upper plastic part 20, thereby the hole wall 14 of the first mounting hole 11 is not less than 30% of H, thereby the upper plastic part 20 can be well fitted with the hole wall 14, and the assembly reliability between the upper plastic part 20 and the cover plate 10 is improved.

[0051] As shown in Figure 4 In some embodiments, the bottom edge of the second chamfer portion 1212 is coplanar with the top surface of the first recess 13. In this way, the hole wall 14 for fitting with the upper plastic in the first mounting hole 11 extends from the top surface of the first recess 13 to the bottom surface of the cover plate 10, and the circumferential height and shape of the hole wall 14 are consistent, i.e. the hole wall 14 is an inner circular surface with a constant height, thereby the upper plastic part 20 can be well fitted.

[0052] As shown in Figure 4As shown, in some embodiments, the angle between the first chamfered portion 1211 and the hole wall 14 is α, satisfying 35°≤α≤60°, and the angle between the second chamfered portion 1212 and the hole wall 14 is β, satisfying 10°≤β≤30°. By rationally designing the angles between the first chamfered portion 1211 and the second chamfered portion 1212 and the hole wall 14, the positioning and guiding effect of the upper plastic part 20 can be effectively achieved, improving assembly efficiency. Furthermore, the first chamfered portion 1211 and the second chamfered portion 1212 are also easy to process and form within this angle range.

[0053] like Figure 4 As shown, in some embodiments, the thickness of the cover plate 10 is H0, and the depth of the first groove 13 is H3, satisfying: H3 / H0 = 30%~50%. Simultaneously, the height of the first boss 12 extending beyond the top surface of the first groove 13 is H4, satisfying: H4 / H0 = 70%~95%. By rationally designing the height of the first boss 12 and the depth of the first groove 13, the anti-torsion effect can be guaranteed while also ensuring the structural strength of the cover plate 10 at the first mounting hole 11.

[0054] like Figure 5 As shown, in some embodiments, both the first boss 12 and the first groove 13 are arc-shaped. Multiple first bosses 12 and multiple first grooves 13 are alternately connected around the first mounting hole 11 to form a ring-shaped structure. The central angle of the first boss 12 is R1, and the central angle of the first groove 13 is R2, satisfying: R2 < R1. It can be understood that since the central angle of the first groove 13 is R2, which is less than the central angle of the first boss 12, that is, the arc length of the first groove 13 is shorter than the arc length of the first boss 12. It is also understandable that, since the first boss 12 mates with the second groove 212, and the first groove 13 mates with the second boss 211, the anti-torsion structure mainly achieves anti-torsion through the mating of the first boss 12 of the cover plate 10 with the second groove 212 of the upper plastic part 20. The second protrusion 211 of the upper plastic part 20 plays an auxiliary role in anti-torsion. The cover plate 10 is made of metal, while the upper plastic part 20 is made of plastic. The strength of metal is much greater than that of plastic. Therefore, by designing the central angle R2 of the first groove 13 to be smaller than the central angle R1 of the first boss 12, the structural strength of the first boss 12 can be significantly increased, improving the anti-torsion effect. As mentioned earlier, since the shape, size, and number of the first boss 12 and the second groove 212 are matched, and the shape, size, and number of the first groove 13 and the second boss 211 are matched, in this case, the sizes of the central angles of the second boss 211 and the second groove 212 constructed on the upper plastic part 20 are in opposite relationships, which will not be elaborated further here.

[0055] Further, in some embodiments, R2 / R1=60%~80%. By reasonable design of the first boss 12 and the central angle of the first groove 13, it is ensured that the first boss 12 and the second boss 211 both have good strength, and the safety and reliability of the anti-twist structure are ensured.

[0056] It can be understood that the cover plate assembly includes the upper plastic part 20, which serves to insulate and isolate the pole 30 from the cover plate 10. In the embodiment, the upper plastic part 20 is made of plastic, and is an independent component formed by, for example, an injection molding process, connected to the cover plate 10 through a certain assembly movement, and pressed against the top surface of the cover plate 10 by the riveting force generated by the flange 31 at the top of the pole 30, and finally combined with the cover plate 10, the pole 30, etc. to form the cover plate assembly.

[0057] As shown in Figure 6 , in combination with Figure 1 and Figure 2 , in some embodiments, the upper plastic part 20 includes a body 21 and a flange 22 arranged at the bottom of the body 21, and the upper plastic part 20 is provided with a second mounting hole 23 penetrating through the body 21 and the flange 22, i.e., the second mounting hole 23 penetrates through the upper plastic part 20 along the thickness direction (up and down direction in the figure), so that the second mounting hole 23 communicates the top surface of the body 21 and the bottom surface of the flange 22, and the pole 30 is arranged to pass through the second mounting hole 23, thereby realizing the insulation and isolation of the cover plate 10 and the pole 30.

[0058] Specifically, the outer contour size of the body 21 is greater than the diameter of the first mounting hole 11, and the outer contour size of the flange 22 is adapted to the inner diameter of the first mounting hole 11, so that when the upper plastic part 20 is operated to make an assembly movement in the direction from top to bottom towards the direction close to the top surface of the cover plate 10, the flange 22 can penetrate into the first mounting hole 11, and the outer surface thereof can be well fitted with the inner wall surface of the first mounting hole 11, and the body 21 can be limited by the top surface of the cover plate 10, thereby avoiding the whole upper plastic part 20 from falling into and passing through the first mounting hole 11. It can be understood that in the assembled cover plate assembly, the body 21 is pressed against the top surface of the cover plate 10 by the riveting force of the pole 30.

[0059] Further, it can be understood that along the outer periphery of the flange 22, the second boss 211 and the second groove 212 are alternately arranged adjacent to each other. It can be understood that along the outer periphery of the flange 22, the second boss 211 and the second groove 212 are constructed adjacent to each other on the bottom surface of the body 21, so that when the upper plastic part 20 is operated to make an assembly movement in the direction from top to bottom towards the direction close to the top surface of the cover plate 10, the second boss 211 and the second groove 212 can make a nested assembly movement with the first groove 13 and the first boss 12 constructed on the cover plate 10, and finally combined into an anti-twist structure.

[0060] It is understood that the alternating arrangement described here refers to the second protrusion 211 and the second groove 212 being arranged alternately and staggered along the circumferential direction surrounding the outer wall of the flange 22. That is, a second groove 212 is provided between two second protrusions 211, and correspondingly, a second protrusion 211 is provided between two second grooves 212. In this way, firstly, in the circumferential direction surrounding the outer wall of the flange 22, staggered second protrusions 211 and second grooves 212 are formed, so that the anti-torsion structure formed after nesting with the first groove 13 and the first protrusion 12 is evenly distributed along the 360-degree circumferential range, the force is more balanced, and the anti-torsion structure is safe and reliable.

[0061] It can also be understood that the adjacency described here means that there is no separation between the second protrusion 211 and the second groove 212. That is, the space defined between the two second protrusions 211 is the second groove 212, and correspondingly, the structure that separates the two second grooves 212 is the second protrusion 211.

[0062] like Figure 6 As shown, and in combination Figure 5 It is understood that the anti-torsion structure described in this embodiment is composed of a first protrusion 12 and a first groove 13 constructed on the cover plate 10, which together cooperate and connect with a second protrusion 211 and a second groove 212 constructed on the upper plastic part 20. Therefore, the shape, size, and number of the first protrusion 12 and the second groove 212 are matched, and the shape, size, and number of the first groove 13 and the second protrusion 211 are matched. Specifically, the height of the first protrusion 12 and the depth of the second groove 212 are matched, so that the first protrusion 12 can be completely nested in the second groove 212. Correspondingly, the height of the second protrusion 211 and the depth of the first groove 13 are matched, so that the second protrusion 211 can be completely nested in the first groove 13, thereby allowing the bottom surface of the upper plastic part 20 to fit well with the top surface of the cover plate 10. To illustrate further, let's take the number of the first boss 12, the first groove 13, the second boss 211, and the second groove 212 as an example. For instance, there are four first bosses 12 and four first grooves 13. Correspondingly, the number of the second bosses 211 and the second grooves 212 on the plastic part 20 that it mates with are also four.

[0063] It can be understood that the cover plate assembly includes the pole post 30, which is electrically connected to the pole group of the internal winding core of the lithium battery when assembled into the lithium battery, so as to serve as the electrical contact of the lithium battery, for the external electrical equipment to be connected to the lithium battery. It can be understood that the pole post 30 is made of metal, such as aluminum, which has good electrical conductivity and is easy to be riveted to the top surface of the cover plate 10 by the riveting process. It can be understood that the pole post 30 forms a flange 31 on the top surface by the riveting process, and the flange 31 is pressed on the top of the upper plastic part 20.

[0064] Of course, it can be understood that the cover plate assembly includes the lower plastic part 50, the sealing ring 60 and other components on one side of the bottom surface of the cover plate 10 in addition to the cover plate 10, the upper plastic part 20 and the pole post 30 mentioned above. Since these components are not related to the purpose of the present application, they will not be described in the present application.

[0065] The present application will be further described below by examples and comparative examples, and the following examples and comparative examples of the present application are designed with reference to the conventional 4680 cylindrical lithium battery.

[0066] Example 1:

[0067] Example 1 provides a cover plate assembly, which includes a cover plate 10 and an upper plastic part 20, wherein the cover plate 10 is provided with a first mounting hole 11 penetrating through and having a circular profile, four first bosses 12 and four first grooves 13 are arranged around the first mounting hole 11, and a chamfer portion 121 is arranged between the top surface of the first boss 12 and the hole wall 14 of the first mounting hole 11, the chamfer portion 121 includes a first chamfer portion 1211 and a second chamfer portion 1212 connected to each other and having different inclination angles. Correspondingly, the bottom of the upper plastic part 20 is provided with a flange 22 having a cylindrical outer profile, the flange 22 is arranged in the first mounting hole 11, and four second bosses 211 and four second grooves 212 are arranged on the bottom surface of the body 21 along the outer periphery of the flange 22, the second bosses 211 and the second grooves 212 correspond to the first grooves 13 and the first bosses 12 on the cover plate 10 one by one and are nested with each other, and together form an anti-torsion structure.

[0068] Wherein, the thickness of the cover plate 10 is H0, the thickness of the cover plate 10 at the first boss 12 is H, the included angle between the first chamfer 1211 and the hole wall 14 of the first mounting hole 11 is a, the vertical height along the thickness direction of the cover plate 10 is H1, the included angle between the second chamfer 1212 and the hole wall 14 of the first mounting hole 11 is β, the vertical height along the thickness direction of the cover plate 10 is H2, the central angle of the first boss 12 is R1, the central angle of the first groove 13 is R2, the depth of the first groove 13 is H3, the height of the first boss 12 beyond the top surface of the first groove 13 is H4, and the following conditions are met: H1 / H=20%, H2 / H=30%, a=45°, β=20°, R2 / R1=70%, H3 / H0=40%, H4 / H0=85%.

[0069] Example 2:

[0070] Example 2 provides a cover plate assembly, which is different from example 1 in that H1 / H=15%, H2 / H=35%, a=40°, β=25°, R2 / R1=75%, H3 / H0=35%, H4 / H0=85%.

[0071] Comparative Example 1:

[0072] Comparative Example 1 provides a cover plate assembly, which is different from example 1 in that H1 / H=50%, H2 / H=5%.

[0073] Comparative Example 2:

[0074] Comparative Example 2 provides a cover plate assembly, which is different from example 1 in that a=85°, β=3°.

[0075] Comparative Example 3:

[0076] Comparative Example 3 provides a cover plate assembly, which is different from example 1 in that R2 / R1=100%.

[0077] Comparative Example 4:

[0078] Comparative Example 4 provides a cover plate assembly, which is different from example 1 in that H3 / H0=10%, H4 / H0=50%.

[0079] The following Table 1 evaluates the anti-twist effect of the cover plate assembly made in the above examples and comparative examples. The specific test method is as follows: using a torque wrench, the clamping groove on the torque wrench is completely wrapped around the upper plastic part 20, holding the torque wrench handle 15 cm away from the center point of the upper plastic part 20 to rotate in the clockwise direction until the plastic part 20 is completely rotated out of the cover plate 10, i.e. the torque fails, and the torque value displayed on the torque wrench is recorded. In order to reduce the accidental error of the data and make the data more true and accurate, three sets of experiments are performed simultaneously for all examples and comparative examples, and the torque value is measured three times, and then the average torque value is taken.

[0080] Table 1

[0081]

[0082] From Table 1, it can be seen that when the height of the complete contact surface between the upper plastic part 20 and the hole wall 14 of the first mounting hole 11 is constant, the H1 / H ratio is large, the H2 / H ratio is small, i.e. the height of the second chamfer portion 1212 is small, and the second chamfer portion 1212 is difficult to guide the upper plastic part 20, resulting in that the upper plastic part 20 cannot be completely assembled with the cover plate 10, thereby reducing the anti-twist effect, affecting the torque effect, and reducing the torque value.

[0083] It can be understood that when assembling the upper plastic part 20, the first chamfer portion 1211 plays a role in preliminarily positioning the upper plastic part 20, i.e. the upper plastic part 20 can be placed on the first chamfer portion 1211 with an included angle α, and the second chamfer portion 1212 plays a role in guiding the upper plastic part 20, which can make the flange 22 of the upper plastic part 20 smoothly enter the first mounting hole 11 along the inclined direction of the second chamfer portion 1212 and completely contact the hole wall 14 of the cover plate 10. From Table 1, it can be seen that when the included angle α is too large, the positioning effect of the first chamfer portion 1211 on the upper plastic part 20 is not obvious, the included angle β is too small, the guiding effect of the second chamfer portion 1212 on the upper plastic part 20 is not obvious, and the upper plastic part 20 is difficult to completely assemble into the cover plate 10, thereby reducing the anti-twist effect, affecting the torque effect, reducing the torque value, and also reducing the assembly efficiency.

[0084] It can be understood that, due to the cooperation of the first boss 12 and the second groove 212, and the cooperation of the first groove 13 and the second boss 211, for the anti-torsion structure, the main anti-torsion is achieved by the cooperation of the first boss 12 of the cover plate 10 and the second groove 212 of the upper plastic part 20, and the second boss 211 of the upper plastic part 20 plays an auxiliary anti-torsion role, and the material of the cover plate 10 is metal, and the material of the upper plastic part 20 is plastic, and the strength of the metal material is much greater than that of the plastic material, so that by designing the central angle of the first groove 13 as R2 to be less than the central angle of the first boss 12 as R1, the structural strength of the first boss 12 can be significantly increased, and the anti-torsion effect is improved. As shown in Table 1, when R2 is less than R1, the anti-torsion effect is better, and when R2 = R1, that is, R2 / R1 = 100%, the anti-torsion effect is reduced.

[0085] As shown in Table 1, if the depth H3 of the first groove 13 is reduced, and the height H4 of the first boss 12 beyond the top surface of the first groove 13 is reduced, the embedding depth of the anti-torsion structure formed between the cover plate 10 and the upper plastic part 20 will be reduced, so that the anti-torsion strength is reduced, and the anti-torsion effect is reduced.

[0086] The embodiment of the present application also provides a cylindrical lithium battery comprising the cover plate assembly of the above embodiment. The cylindrical lithium battery of the embodiment of the present application has the cover plate assembly of the above embodiment, so that the upper plastic part is not easy to be twisted relative to the cover plate during long-time use or use in harsh working conditions, the connection stability between them is ensured, the stability of the riveting of the pole post flange is further ensured, and the pole post is not easy to be twisted, and has the characteristics of high reliability.

[0087] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" 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 embodiment. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0088] Although the embodiments of the present embodiment have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present embodiment, and the scope of the present embodiment is defined by the claims and their equivalents.

Claims

1. A cover assembly, characterized by The utility model relates to a cover plate (10) is provided with the first installation hole (11) that penetrates, the first installation hole (11) is circular, and the edge of the first installation hole (11) is opened along the top surface of the cover plate (10) and is alternately provided with the first boss (12) and the first recess (13) that abut with each other, and the top surface of the first boss (12) and the hole wall (14) of the first installation hole (11) are provided with the chamfer (121), the chamfer (121) includes the first chamfer (1211) and the second chamfer (1212) that are connected and have different inclination angles, the top surface of the first boss (12), the first chamfer (1211), the second chamfer (1212) and the hole wall (14) are sequentially connected, the thickness of the cover plate (10) at the first boss (12) is H, the vertical height of the first chamfer (1211) along the thickness direction of the cover plate (10) is H1, the vertical height of the second chamfer (1212) along the thickness direction of the cover plate (10) is H2, satisfy: H1 / H=10%~30%, H2 / H=20%~40%, the included angle of the first chamfer (1211) and the hole wall (14) is alpha, satisfy, 35 DEG <= alpha <= 60 DEG, the included angle of the second chamfer (1212) and the hole wall (14) is beta, satisfy: 10 DEG <= beta <= 30 DEG; The upper plastic part (20) includes a body (21) and a flange (22) provided at the bottom of the body (21), the flange (22) is cylindrical, the upper plastic part (20) is provided with a second installation hole (23) penetrating the body (21) and the flange (22), the body (21) abuts against the top surface of the cover plate (10), the flange (22) is arranged in the first installation hole (11), and a second boss (211) and a second recess (212) that abut with each other are alternately arranged along the outer periphery of the flange (22); The pole (30) is arranged in the second installation hole (23); Wherein, each first boss (12) is nested in each second recess (212) one by one, and each second boss (211) is nested in each first recess (13) one by one, so as to limit the rotation of the upper plastic part (20) relative to the cover plate (10). The bottom edge of the second chamfer (1212) is coplanar with the top surface of the first recess (13).

2. The cover plate assembly of claim 1, wherein, The first boss (12) and the first recess (13) are both arc-shaped, a plurality of first bosses (12) and a plurality of first recesses (13) are alternately connected to form a circular ring structure around the first installation hole (11), the central angle of the first boss (12) is R1, the central angle of the first recess (13) is R2, and R2 < R1 is satisfied.

3. The cover plate assembly of claim 1 or 2, wherein, R2 / R1=60%~80%.

4. The cover plate assembly of claim 3, wherein, The thickness of the cover plate (10) is H0, and the depth of the first recess (13) is H3, and H3 / H0=30%~50% is satisfied.

5. The cover plate assembly of claim 1 or 2, wherein, ​ 6. The cover plate assembly of claim 1 or 2, wherein, The thickness of the cover plate (10) is H0, and the height of the first boss (12) beyond the top surface of the first groove (13) is H4, satisfying: H4 / H0=70%~95%.

7. A cylindrical lithium battery characterized by The cover plate assembly as claimed in any one of claims 1 to 6.

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