Cover plate assembly and battery cell

Abstract

The application relates to the technical field of batteries and discloses a cover plate assembly and a battery cell, wherein the cover plate assembly comprises a cover plate body provided with a pole hole and a plurality of limiting holes, the limiting holes are arranged at intervals around the circumferential direction of the pole hole, the pole hole and the limiting holes both penetrate through the cover plate body along the Z direction; a pole comprises a pole body and a bottom plate, the pole body is arranged in the pole hole, the bottom plate is located on the lower side of the cover plate body along the Z direction, and the bottom plate is provided with a limiting groove corresponding to the limiting hole; a first plastic part comprises a plastic part body and a plurality of limiting bosses, the plastic part body is sleeved on the pole body, the limiting bosses are fixedly connected to the lower surface of the plastic part body along the Z direction, the plurality of limiting bosses correspond to the plurality of limiting holes one by one, and each limiting boss is inserted into the limiting hole and the limiting groove corresponding to the limiting boss. The limiting bosses are simultaneously inserted into the limiting holes and the limiting grooves corresponding to the limiting bosses, the relative fixation between the first plastic part and the cover plate body and the pole along the circumferential direction is realized, and the torsion resistance of the pole and the first plastic part is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to cover plate assemblies and battery cells. Background Technology

[0002] The cover plate assembly is a crucial component of the battery cell, forming a sealed space with the housing to accommodate the electrode assembly. Current cover plate assemblies primarily consist of an aluminum plate, electrode posts, a riveting block, upper plastic, lower plastic, and a sealing ring. Electrical connection is achieved by pressing and riveting the electrode posts to form an inverted connection with the riveting block and then welding. However, using a riveting structure for the electrode posts requires additional riveting blocks, increasing costs. Furthermore, the riveting block and electrode posts require pressing and welding, adding process steps and reducing production efficiency and yield. Existing technologies include injection molding an upper plastic part between the electrode post and the aluminum plate, directly connecting the electrode post and aluminum plate through the injection-molded part, eliminating the need for a riveting block. However, relative rotation occurs between the plastic part and the aluminum plate / electrode post, resulting in poor torsional resistance of the electrode post and affecting the safety of the battery cell. Summary of the Invention

[0003] This invention provides a cover plate assembly and a battery cell to solve the problem of poor torsional resistance of the electrode post.

[0004] In a first aspect, the present invention provides a cover plate assembly, comprising: a cover plate body having an electrode post hole and a plurality of limiting holes, the plurality of limiting holes being circumferentially spaced around the electrode post hole, the electrode post hole and the limiting holes both penetrating the cover plate body along the Z direction; an electrode post including a column body and a base plate, the column body being inserted into the electrode post hole, the base plate being located on the lower side of the cover plate body along the Z direction, the base plate having a limiting groove corresponding to the limiting hole; and a first plastic part including a plastic part body and a plurality of limiting bosses, the plastic part body being sleeved on the column body, the limiting bosses being fixedly connected to the lower surface of the plastic part body along the Z direction, the plurality of limiting bosses corresponding one-to-one with the plurality of limiting holes, each limiting boss being inserted into the corresponding limiting hole and the limiting groove.

[0005] Beneficial effects: By opening several limiting holes around the pole hole on the cover plate body, and opening several limiting grooves corresponding to the limiting holes on the bottom plate of the pole located on the lower side of the cover plate body, and setting several limiting bosses on the lower side of the first plastic part, by simultaneously inserting each limiting boss into a corresponding limiting hole and a limiting groove, the first plastic part and the cover plate body can be mutually limited along the circumferential direction of the pole hole, and the first plastic part and the pole can be mutually limited along the circumferential direction of the pole hole. This achieves relative fixation of the first plastic part, the cover plate body, and the pole along the circumferential direction, preventing relative rotation between the first plastic part and the cover plate body or the pole, thereby improving the torsional resistance of the pole and the first plastic part. Furthermore, the limiting bosses are sequentially inserted into the cover plate body and the pole along the axial direction of the pole. The first plastic part can be simultaneously fixed to the cover plate body and the pole through the limiting bosses. The structure is simple, easy to process and form, facilitates the smooth assembly process, and helps to improve the assembly efficiency of the cover plate assembly.

[0006] In one alternative embodiment, the pole hole has a first centerline extending along the Z direction, and the limiting hole is formed by a portion of the hole wall of the pole hole being recessed radially away from the first centerline.

[0007] Beneficial effects: By setting a limiting hole formed by a portion of the hole wall of the pole post hole recessed radially away from the first center line, the limiting hole is connected to the pole post hole, which facilitates the processing and forming of the limiting hole and the forming of the limiting boss on the first plastic part, thus improving the production yield.

[0008] In one optional embodiment, the limiting hole is an arc-shaped hole, and the orthographic projection of the arc-shaped hole along the Z direction in the XY plane has an opening side that is radially close to the first center line and a first arc segment that is radially away from the first center line.

[0009] The arc length D of the first arc segment, and the arc length d of the opening side along the circumference of the pole hole in the XY plane, wherein D and d satisfy the following relationship: d+0.5mm≤D≤d+2mm; and / or, the value range of d is: 3 mm≤d≤8 mm; and / or, the value range of D is: 3.5 mm≤D≤10 mm;

[0010] And / or, the radial dimension of the arc-shaped hole is H, wherein 0.8 mm ≤ H ≤ 3.2 mm.

[0011] Beneficial effects: By setting D to be greater than d and limiting the difference between D and d to within the range of 0.5 mm to 2 mm, it can be ensured that the interaction force between the first sidewall and the limiting boss can be evenly distributed along the circumference of the pole hole, thereby avoiding stress concentration on the limiting boss and the cover plate body. It can also ensure the assembly effect, prevent the limiting boss from coming out of the opening side of the limiting hole toward the center of the pole hole, enhance the connection strength and torsional strength, and ensure that the limiting hole can provide sufficient setting space for the limiting boss in the radial direction, ensuring that the limiting boss has sufficient structural strength, thereby preventing the limiting boss from breaking during use, thus ensuring the torsional performance of the first plastic part and improving the reliability of the cover plate assembly.

[0012] And / or, by limiting H to a value within the range of 0.8 mm to 3.2 mm, it is possible to ensure that the first plastic part has sufficient torsional resistance while avoiding excessive damage to the structural strength of the cover plate body, thereby improving the reliability of the cover plate assembly while ensuring the torsional resistance of the first plastic part 3.

[0013] In one optional implementation, the number of limiting holes is N, where 2≤N≤30, and N is a positive integer.

[0014] Beneficial effects: By limiting the number of limiting holes to between 2 and 30, it can effectively prevent relative rotation between the first plastic part and the cover plate body and the pole in the circumferential direction, thereby ensuring the torsional resistance of the pole and the first plastic part. It can also avoid the structure being too complicated, thereby reducing the processing difficulty and improving the processing efficiency.

[0015] In one optional embodiment, the limiting groove is formed by a portion of the upper surface of the base plate recessed along the Z direction, the recess depth of the limiting groove along the Z direction is t, and the thickness of the base plate along the Z direction is T.

[0016] Where t and T satisfy the following relationship: 0.15≤t / T≤0.5;

[0017] And / or, the recess depth t of the limiting groove along the Z direction is in the range of: 0.3 mm ≤ t ≤ 0.8 mm;

[0018] And / or, the thickness T of the base plate along the Z direction is in the range of 1.5 mm ≤ T ≤ 2.5 mm.

[0019] Beneficial effects: By limiting t / T to a value within the range of 0.15 to 0.5, it can prevent the limiting boss from coming out of the limiting groove, thereby ensuring the stability of the fit between the limiting boss and the limiting groove, preventing relative rotation between the pole post and the first plastic part, improving the torsional resistance of the pole post, and ensuring the structural strength of the base plate itself, improving the reliability of the pole post, thereby ensuring the reliability of the cover plate assembly.

[0020] And / or, by limiting t to a value within the range of 0.3 mm to 0.8 mm, the limiting groove has a reasonable recess depth, which can ensure that the limiting groove can stably cooperate with the limiting boss, prevent relative rotation between the pole post and the first plastic part, thereby improving the pole post's torsional resistance, and also ensure that the base plate of the pole post has sufficient structural strength, thereby improving the pole post's reliability and service life.

[0021] And / or, by limiting T to a value within the range of 1.5 mm to 2.5 mm, the structural strength of the base plate itself can be guaranteed, preventing deformation and damage during use, improving the reliability and safety of the cover plate assembly and the cell, while also avoiding excessive weight of the terminal post, reducing costs, and preventing the base plate from occupying too much internal space of the cell, thereby helping to improve the energy density of the cell.

[0022] In one optional embodiment, the upper surface of the cover plate body is provided with a groove, the groove including a plurality of groove segments circumferentially spaced around the first center line, each groove segment being connected between two adjacent limiting holes; the first plastic part also includes a plurality of reinforcing parts, the reinforcing parts being fixedly connected to the lower surface of the plastic part body, each reinforcing part being connected between two adjacent limiting bosses, and the reinforcing parts being located in the groove.

[0023] Beneficial effects: By providing a groove on the upper surface of the cover plate body, and the groove including several groove segments that are alternately distributed with several limiting holes along the circumferential direction, the groove provides space for the reinforcing part. The reinforcing part is connected to the root of two adjacent limiting bosses to strengthen the structural strength of the root of the limiting boss, thereby improving the structural strength of the limiting boss and preventing the limiting boss from breaking from the root when there is a relative rotation tendency between the first plastic part and the cover plate body, thereby improving the reliability of the limiting boss and ensuring the torsional resistance of the first plastic part. Furthermore, by providing a groove to accommodate the reinforcing part, the reinforcing part is prevented from being directly supported on the upper surface of the cover plate body, thereby ensuring that the lower surface of the plastic part body is tightly fitted with the upper surface of the cover plate body, improving the sealing between the first plastic part and the cover plate body, and increasing the connection area between the first plastic part and the cover plate body, thus enhancing the tensile strength of the cover plate assembly along the Z direction.

[0024] In one optional embodiment, the dimension of the reinforcing part along the Z direction is b, and the dimension difference between the limiting boss and the reinforcing part along the Z direction is a;

[0025] Wherein, b and a satisfy the following relationship: 0.25≤b / a≤0.65; and / or, the value range of a is: 1.0 mm≤a≤1.8 mm; and / or, the value range of b is: 0.4 mm≤b≤0.8 mm.

[0026] Beneficial effects: By limiting b / a to a value within the range of 0.25 to 0.65, it can be ensured that the reinforcing part has sufficient structural reinforcement effect on the limiting boss, improve the reliability of the first plastic part, and ensure the torsional resistance of the first plastic part and the pole post. It can also avoid the reinforcing part being too large in the Z direction, which would lead to excessive groove depth, thereby ensuring that the cover plate body has sufficient structural strength and improving the reliability of the cover plate assembly.

[0027] And / or, by limiting a to a value within the range of 1.0 mm to 1.8 mm, the limiting boss protrudes downward relative to the reinforcing part by a reasonable size in the Z direction. This can avoid insufficient insertion fit size between the limiting boss and the limiting groove in the Z direction, and ensure that the limiting boss has sufficient structural strength. This ensures a stable fit between the limiting boss and the limiting groove, prevents the limiting boss from coming out of the limiting groove, prevents relative rotation between the pole post and the first plastic part, and thus improves the torsional resistance of the pole post.

[0028] And / or, by limiting b to a value within the range of 0.4 mm to 0.8 mm, it is possible to ensure that the reinforcing part itself has sufficient structural strength, thereby ensuring the structural reinforcement effect of the reinforcing part on the limiting boss, improving the reliability of the first plastic part, ensuring the torsional resistance of the first plastic part and the pole post, and avoiding the excessive size of the reinforcing part along the Z direction, which would lead to excessive recess depth of the groove, thereby ensuring that the cover plate body has sufficient structural strength and improving the reliability of the cover plate assembly.

[0029] In one optional embodiment, the column has a second centerline extending along the Z direction and an outer peripheral surface radially away from the second centerline, and an annular groove surrounding the second centerline is formed on the outer peripheral surface of the column; the plastic body is annular, and the first plastic part further includes a first protruding ring, which is fixedly connected to the inner ring of the plastic body and inserted into the annular groove.

[0030] Beneficial effects: By opening an annular groove on the outer circumference of the column and setting a first protruding ring on the inner ring wall of the plastic part body, the first protruding ring is inserted into the annular groove, thereby achieving mutual positioning between the first plastic part and the pole post along the pole post axis, ensuring the relative stability between the pole post and the first plastic part along the axis, and improving the reliability of the cover plate assembly.

[0031] In one alternative embodiment, the first plastic part is injection molded between the pole and the cover plate body.

[0032] Beneficial effects: Injection molding is a relatively simple method. The first plastic part can connect the terminal post and the cover plate body at the same time, and ensure the insulation and sealing between the terminal post and the cover plate body. It eliminates the use of the riveting block in the traditional battery cell, reduces costs, and improves production efficiency.

[0033] Secondly, the present invention also provides a battery cell, comprising: a housing having an open end; an electrode assembly disposed inside the housing; and the aforementioned cover plate assembly covering the open end of the housing. Since the battery cell includes the cover plate assembly and has the same effect as the cover plate assembly, it will not be described further here. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present invention;

[0036] Figure 2 for Figure 1 Top view of the cover plate assembly shown;

[0037] Figure 3 for Figure 2 A cross-sectional view along the CC direction;

[0038] Figure 4 for Figure 3 A magnified view of part of E in the diagram;

[0039] Figure 5 for Figure 1 The bottom view of the cover plate assembly shown;

[0040] Figure 6 for Figure 1 Side view of the cover plate assembly shown;

[0041] Figure 7 A schematic diagram showing the positional relationship between the cover plate body and the pole post before assembling the first plastic part;

[0042] Figure 8 for Figure 7 A magnified view of part of F;

[0043] Figure 9 for Figure 7 A top view showing the positional relationship between the cover plate body and the pole post;

[0044] Figure 10 for Figure 9 A magnified view of part of J;

[0045] Figure 11 for Figure 9Cross-sectional view along the GG direction;

[0046] Figure 12 for Figure 11 A magnified view of part M in the diagram;

[0047] Figure 13 for Figure 7 A side view showing the positional relationship between the cover plate body and the pole post;

[0048] Figure 14 This is a schematic diagram of the structure of a first plastic part according to an embodiment of the present invention;

[0049] Figure 15 for Figure 14 The front view of the first plastic part is shown;

[0050] Figure 16 for Figure 14 A structural schematic diagram of the first plastic part from its bottom view;

[0051] Figure 17 for Figure 14 The bottom view of the first plastic part shown;

[0052] Figure 18 for Figure 14 A top view of the first plastic part shown;

[0053] Figure 19 for Figure 18 A cross-sectional view along the KK direction;

[0054] Figure 20 This is a schematic diagram of the structure of a pole post according to an embodiment of the present invention;

[0055] Figure 21 for Figure 20 The front view of the pole column is shown;

[0056] Figure 22 for Figure 20 A top view of the pole shown;

[0057] Figure 23 for Figure 22 A cross-sectional view along the PP direction.

[0058] Explanation of reference numerals in the attached figures:

[0059] 1. Cover plate body; 11. Pole post hole; 12. Limiting hole; 121. First arc segment; 122. Second arc segment; 13. Groove; 131. Slot segment; 2. Pole post; 21. Post body; 211. Annular groove; 212. Third convex ring; 22. Base plate; 221. Limiting groove; 3. First plastic part; 301. First through hole; 31. Plastic part body; 32. Limiting boss; 33. Reinforcing part; 34. First convex ring; 35. Second convex ring; 4. Second plastic part. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The cover plate assembly is a crucial component of the battery cell, forming a sealed space with the housing to accommodate the electrode assembly. Current cover plate assemblies primarily consist of an upper plastic layer, a riveting block, electrode posts, a bare aluminum plate, a lower plastic layer, and a sealing ring. The upper and lower plastic layers are located on opposite sides of the bare aluminum plate, while the riveting block is situated on the side of the upper plastic layer facing away from the aluminum plate. The electrode posts pass sequentially through through holes in the aluminum plate, the upper plastic layer, and the riveting block. Electrical connection is achieved by pressing the electrode posts together to form an inverted connection with the riveting block and then welding them. However, using a riveting structure for the electrode posts requires additional riveting blocks, increasing costs. Furthermore, the riveting blocks and electrode posts require pressing and welding, adding process steps and reducing production efficiency and yield. Existing technologies include solutions that use injection molding to form an upper plastic part between the electrode post and the aluminum plate, directly connecting the electrode post and the aluminum plate through the injection molded part, eliminating the use of rivet blocks. However, the electrode post is usually welded with a busbar, which is used to realize the electrical connection between cells and / or between cells and external circuits. When the cell is subjected to external force, the external force can easily cause the electrode post to rotate around the center line of the electrode post through the busbar and other structures. There is no limiting structure between the plastic part and the aluminum plate / electrode post, and the plastic part and the aluminum plate / electrode post can easily rotate relative to each other around the center line of the electrode post, resulting in poor torsional resistance of the electrode post, which in turn leads to loosening of the electrode post and affects the safety of the cell.

[0062] The following is combined Figures 1 to 23 The following describes embodiments of the present invention.

[0063] According to an embodiment of the present invention, in one aspect, a cover plate assembly is provided, including: a cover plate body 1, a pole post 2, and a first plastic part 3. The cover plate body 1 has a pole post hole 11 and several limiting holes 12. The several limiting holes 12 are arranged circumferentially around the pole post hole 11. The pole post hole 11 and the limiting holes 12 both penetrate the cover plate body 1 along the Z direction. The pole post 2 includes a column body 21 and a base plate 22. The column body 21 passes through the pole post hole 11. The base plate 22 is located on the lower side of the cover plate body 1 along the Z direction. The base plate 22 has a limiting groove 221 corresponding to the limiting hole 12. The first plastic part 3 includes a plastic part body 31 and several limiting bosses 32. The plastic part body 31 is sleeved on the column body 21. The limiting bosses 32 are fixedly connected to the lower surface of the plastic part body 31 along the Z direction. The several limiting bosses 32 correspond one-to-one with the several limiting holes 12. Each limiting boss 32 is inserted into its corresponding limiting hole 12 and limiting groove 221. Here, the Z direction refers to Figure 1 , Figure 3 , Figure 4 and Figure 6 The direction of the "Z" indicated by the middle arrow.

[0064] It should be noted that, as Figure 1 As shown, the cover assembly has two perpendicular X, Y, and Z directions. Specifically, the X direction is the length direction of the cover assembly, the Y direction is the width direction of the cover assembly, and the Z direction is the thickness direction of the cover assembly. The cover body 1 has upper and lower sides arranged opposite to each other along the Z direction. When the cover assembly is assembled with the housing, the side of the cover body 1 facing the housing along the Z direction is the lower side, and the side of the cover body 1 away from the housing along the Z direction is the upper side. The "lower surface" mentioned refers to the lower surface along the Z direction, specifically the surface pointing towards the inner cavity of the housing along the Z direction.

[0065] By applying the cover plate assembly of this embodiment, by opening a plurality of limiting holes 12 around the pole post hole 11 on the cover plate body 1, and opening a plurality of limiting grooves 221 corresponding one-to-one with the plurality of limiting holes 12 on the bottom plate 22 of the pole post 2 located on the lower side of the cover plate body 1, and by setting a plurality of limiting bosses 32 on the lower side of the first plastic part 3, by simultaneously inserting each limiting boss 32 into a corresponding limiting hole 12 and a limiting groove 221, the mutual limiting of the first plastic part 3 and the cover plate body 1 along the circumference of the pole post hole 11 can be achieved, as well as the mutual limiting of the first plastic part 3 and the pole post 2 along the pole post hole 11. The circumferential positioning of the post holes 11 achieves relative fixation between the first plastic part 3 and the cover plate body 1 and the pole post 2, preventing relative rotation between the first plastic part 3 and the cover plate body 1 or the pole post 2, thereby improving the torsional resistance of the pole post 2 and the first plastic part 3. Furthermore, the limiting boss 32 is sequentially inserted into the cover plate body 1 and the pole post 2 along the axial direction of the pole post 2. The limiting boss 32 can simultaneously fix the first plastic part 3 to the cover plate body 1 and the pole post 2. The structure is simple, easy to process and form, facilitates the smooth assembly process, and helps to improve the assembly efficiency of the cover plate assembly.

[0066] It should be noted that the projection of the limiting boss 32 along the Z direction in the XY plane is the same as the opening shape of the limiting hole 12 in the XY plane and the opening shape of the limiting groove 221 in the XY plane, so as to ensure that the limiting boss 32 can be smoothly inserted into the limiting hole 12 and the limiting groove 221, and to ensure the stability after insertion.

[0067] It should be noted that the orthographic projection contour of the base plate 22 of the pole post 2 in the XY plane along the Z direction is larger than the orthographic projection contour of the column 21 in the XY plane along the Z direction, and the contour area of ​​the base plate 22 in the XY plane is larger than the opening area of ​​the pole post hole 11, so as to restrict the pole post 2 from exiting the pole post hole 11 from bottom to top along the Z direction; the limiting groove 221 is formed on the upper surface of the base plate 22, and the limiting groove 221 opens upward so that the limiting boss 32 after passing through the limiting hole 12 can be directly inserted into the limiting groove 221 from top to bottom. Here, "facing upward" refers to facing upward along the Z direction, that is, the limiting groove 221 opens in the Z direction towards the direction close to the cover plate body 1.

[0068] In one embodiment, the pole hole 11 has a first centerline extending along the Z direction, and the limiting hole 12 is formed by a portion of the hole wall of the pole hole 11 recessed radially away from the first centerline. The pole hole 11 is a circular hole, and radial direction refers to the radial direction of the pole hole 11, specifically, a direction perpendicular to the Z direction and passing through the first centerline. By providing the limiting hole 12, which is formed by a portion of the hole wall of the pole hole 11 recessed radially away from the first centerline, the limiting hole 12 communicates with the pole hole 11, facilitating the processing and forming of the limiting hole 12, and also facilitating the forming of the limiting boss 32 on the first plastic part 3, thereby improving production yield.

[0069] Alternatively, in other embodiments, the limiting hole 12 and the pole post hole 11 can be arranged radially spaced apart. The limiting hole 12 is a through hole penetrating the cover plate body 1 along the Z direction. The position of the limiting boss 32 is adjusted according to the limiting hole 12. Similarly, the circumferential limiting between the first plastic part 3 and the cover plate body 1 can be achieved by inserting the limiting boss 32 into the limiting hole 12. Of course, the position of the limiting groove 221 on the pole post 2 is also adjusted according to the limiting hole 12, which will not be described in detail here.

[0070] In one embodiment, further combination Figures 8 to 10 As shown, the limiting hole 12 is an arc-shaped hole. The orthographic projection of the arc-shaped hole along the Z direction in the XY plane has an opening side that is radially close to the first center line and a first arc segment 121 that is radially away from the first center line. The arc length D of the first arc segment 121 is d, and the arc length d of the opening side along the circumference of the pole hole 11 in the XY plane is d. D and d satisfy the relationship: d+0.5mm≤D≤d+2mm, and the units of D and d are both mm. It should be noted that the pole post hole 11 is a circular hole, and a number of limiting holes 12 are located on the same circular ring surrounding the pole post hole 11. This circular ring is referred to as the first circular ring. The number of limiting holes 12 are several sections arranged circumferentially on the first circular ring. The opening side of the limiting hole 12, which is radially close to the first center line, is located on the inner ring of the first circular ring. The arc connecting the two ends of the opening side in the XY plane is the second arc segment 122. The arc length of the second arc segment 122 is d. The arc length of the second arc segment 122 is less than the arc length of the first arc segment 121, that is, d < D. This forms an undercut hole arranged radially along the pole post hole 11, which prevents the limiting boss 32 from coming out radially from the opening side of the limiting hole 12 toward the first center line, thereby improving the connection strength between the first plastic part 3 and the cover plate body 1 and ensuring the assembly effect.

[0071] It should be noted that the arc-shaped hole of the limiting hole 12 has two first sidewalls arranged opposite each other along the circumference of the first ring. During the use of the cover plate assembly, the force of the relative torsional tendency between the cover plate body 1 and the first plastic part 3 along the circumference is applied to the limiting boss 32 of the first plastic part 3 through the first sidewalls. If the orthographic projection of the first sidewall along the Z direction in the XY plane extends radially along the pole hole 11, the interaction force between the first sidewall and the limiting boss 32 is perpendicular to the radial direction. Thus, the force can be evenly distributed along the circumference, avoiding stress concentration and reducing damage to the limiting boss 32 and the cover plate body 1. If D is greater than d+2mm, the difference between D and d is too large, and the deviation angle between the orthographic projection of the first sidewall along the Z direction in the XY plane and the radial direction of the pole hole 11 is too large. If the angle between the interaction force between the first sidewall and the limiting boss 32 and the circumferential direction of the pole hole 11 is too large, it will not be conducive to the uniform distribution of the force and will easily cause damage to the limiting boss 32 or the cover plate body 1. If D is less than d+0.5mm, the difference between the first arc segment 121 and the second arc segment 122 on the opening side of the limiting hole 12 will be too small, the undercut limiting effect of the limiting hole 12 will not be obvious, the limiting boss 32 will easily come out of the limiting hole 12, and the reliability will be poor. In addition, if in order to ensure that the orthogonal projection of the first sidewall along the Z direction in the XY plane extends radially along the pole hole 11, the radial recess depth of the limiting hole 12 will be too small, and the radial dimension of the limiting boss 32 in the limiting hole 12 will be too small, resulting in insufficient structural strength and easy breakage during use, and poor reliability.

[0072] Therefore, by setting D to be greater than d and limiting the difference between D and d to a range of 0.5 mm to 2 mm, it is possible to ensure that the interaction force between the first sidewall and the limiting boss 32 can be evenly distributed along the circumference of the pole post hole 11, thereby avoiding stress concentration on the limiting boss 32 and the cover plate body 1. It is also possible to ensure the assembly effect, prevent the limiting boss 32 from coming out of the opening side of the limiting hole 12 toward the center of the pole post hole, enhance the connection strength and torsional strength, and ensure that the limiting hole 12 can provide sufficient space for the limiting boss 32 in the radial direction, ensuring that the limiting boss 32 has sufficient structural strength, thereby preventing the limiting boss 32 from breaking during use, thus ensuring the torsional performance of the first plastic part 3 and improving the reliability of the cover plate assembly.

[0073] Optionally, D is greater than d, and the difference between D and d is any one of 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, or a value between any two of these values.

[0074] In one embodiment, the value of d is in the range of 3 mm ≤ d ≤ 8 mm. If d is less than 3 mm, the arc length of the opening side of the limiting hole 12 along the circumference of the pole hole 11 in the XY plane is too small, making it difficult to process and form. It will also result in the circumferential dimension of the inner ring of the limiting boss 32 being too small, resulting in poor structural strength and stress concentration problems. If d is greater than 8 mm, the arc length of the opening side of the limiting hole 12 along the circumference of the pole hole 11 in the XY plane is too large, and the circumferential dimension of a single limiting hole 12 on the cover plate body 1 is too large, causing greater structural damage to the cover plate body 1. This weakens the structural strength of the solid part of the cover plate body 1 located between two adjacent limiting holes 12, making it prone to damage during use and resulting in poor reliability. Therefore, by limiting d to a value between 3 mm and 8 mm, it is possible to ensure the smooth processing and forming of the limiting hole 12 and the structural strength of the limiting boss 32 located in the limiting hole 12, while also avoiding excessive damage to the cover plate body 1 caused by the limiting hole 12, thereby ensuring the structural strength of the cover plate body 1 and the reliability of the cover plate assembly.

[0075] Optionally, the value of d is any one of 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, or a value between any two of these values.

[0076] In one embodiment, the value of D is in the range of 3.5 mm ≤ D ≤ 10 mm. If D is less than 3.5 mm, the arc length of the first arc segment 121 of the limiting hole 12 on the radial side away from the pole hole 11 is too small, resulting in the limiting hole 12 being too small in the circumferential direction, making it difficult to process and forming, and also resulting in the limiting boss 32 having too small a circumferential dimension and poor structural strength; if D is greater than 10 mm, the arc length of the first arc segment 121 is too large, resulting in the limiting hole 12 being too large in the circumferential direction, causing greater damage to the structure of the cover plate body 1, resulting in poor structural strength of the cover plate body 1, and making it prone to damage during use. Therefore, by limiting D to a value between 3.5 mm and 10 mm, the limiting hole 12 has a reasonable size along the circumferential direction of the pole hole. This ensures that the limiting hole 12 can be smoothly processed and formed, and that the structural strength of the limiting boss 32 located in the limiting hole 12 is guaranteed, thereby ensuring the torsional resistance of the first plastic part 3 relative to the cover plate body 1. It also avoids the limiting hole 12 causing excessive damage to the cover plate body 1, thereby ensuring the structural strength of the cover plate body 1 and the reliability of the cover plate assembly.

[0077] Optionally, the value of D is any one of 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or a value between any two of these values.

[0078] In one embodiment, the radial dimension of the arc-shaped hole is H, where 0.8 mm ≤ H ≤ 3.2 mm. It should be noted that the limiting boss 32 fills the limiting hole 12. If H is less than 0.8 mm, the radial space provided by the limiting hole 12 for the limiting boss 32 is insufficient, resulting in the limiting boss 32 being too thin radially, having poor structural strength, and being prone to breakage under stress. This cannot effectively guarantee the torsional resistance between the first plastic part 3, the cover plate body 1, and the pole post 2. If H is greater than 3.2 mm, the radial space provided by the limiting hole 12 for the limiting boss 32 is too large, excessively damaging the structural strength of the cover plate body 1, reducing the structural strength and reliability of the cover plate body 1. Therefore, by limiting H to a value within the range of 0.8 mm to 3.2 mm, it is possible to ensure that the first plastic part 3 has sufficient torsional resistance while avoiding excessive damage to the structural strength of the cover plate body 1, thereby improving the reliability of the cover plate assembly while ensuring the torsional resistance of the first plastic part 3.

[0079] Optionally, the value of H is any one of 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, or a value between any two of these values.

[0080] In one embodiment, the number of limiting holes 12 is N, where 2 ≤ N ≤ 30, and N is a positive integer. The N limiting holes 12 are distributed circumferentially around the pole post hole 11. If N is less than 2 (i.e., N equals 1), then the number of limiting holes 12, limiting bosses 32, and limiting grooves 221 is only 1, which cannot effectively provide circumferential limiting. The first plastic part 3 and the cover plate body 1, and the first plastic part 3 and the pole post 2, still tend to rotate relative to each other around the first centerline of the pole post hole 11. If N is greater than 30, the number of limiting holes 12 is too large, resulting in a complex structure, increased processing difficulty, and hindering production efficiency. Therefore, by selecting a number of limiting holes 12 between 2 and 30, relative rotation along the circumference between the first plastic part 3 and the cover plate body 1, and the pole post 2 can be effectively prevented, thus ensuring the torsional resistance of the pole post 2 and the first plastic part 3. This also avoids an overly complex structure, thereby reducing processing difficulty and improving processing efficiency.

[0081] Optionally, the value of N is any one of 2, 4, 5, 8, 10, 12, 15, 20, 25, 30 or a value between any two values.

[0082] Preferably, a plurality of pole holes 11 are evenly distributed along the circumference of the pole holes 11 to ensure the uniformity of the distribution of the plurality of pole holes 11 on the cover plate body 1 and improve the uniformity of the force on the cover plate body 1.

[0083] In one embodiment, further combination Figure 4 and Figure 23 As shown, the limiting groove 221 is formed by a portion of the upper surface of the base plate 22 recessed along the Z direction. The recess depth of the limiting groove 221 along the Z direction is t, and the thickness of the base plate 22 along the Z direction is T. The relationship between t and T is: 0.15 ≤ t / T ≤ 0.5. It should be noted that the units of t and T are both mm. The upper surface refers to the upper surface along the Z direction, that is, the upper surface of the base plate 22 is the surface of the base plate 22 closest to the cover plate body 1 along the Z direction. The limiting groove 221 is formed by a portion of the upper surface of the base plate 22 recessed downwards along the Z direction. The end of the limiting boss 32, away from the plastic part body 31 along the Z direction, is inserted into the limiting groove 221, achieving circumferential limiting between the first plastic part 3 and the pole post 2, preventing relative rotation between the pole post 2 and the first plastic part 3. If t / T is less than 0.15, the depth of the recess in the limiting groove 221 is too small relative to the thickness of the base plate 22. When the pole post 2 and the first plastic part 3 have a tendency to rotate relative to each other, the limiting boss 32 is easy to fall out of the limiting groove 221 and lose its circumferential limiting function. If t / T is greater than 0.5, the depth of the recess in the limiting groove 221 is too large relative to the thickness of the base plate 22, causing excessive damage to the base plate 22 and affecting the structural strength of the base plate 22. The base plate 22 is prone to breakage at the limiting groove 221 during use.

[0084] Therefore, by limiting t / T to a value within the range of 0.15 to 0.5, it is possible to prevent the limiting boss 32 from coming out of the limiting groove 221, thereby ensuring the stability of the fit between the limiting boss 32 and the limiting groove 221, preventing relative rotation between the pole post 2 and the first plastic part 3, improving the torsional resistance of the pole post 2, and ensuring the structural strength of the base plate 22 itself, thereby improving the reliability of the pole post 2 and ensuring the reliability of the cover plate assembly.

[0085] Optionally, the value of t / T is any one of 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or a value between any two values.

[0086] In one embodiment, the recess depth t of the limiting groove 221 along the Z direction ranges from 0.3 mm to 0.8 mm. If t is less than 0.3 mm, the recess depth of the limiting groove 221 is too small, the limiting groove 221 is too shallow, and the limiting boss 32 is easy to dislodge from the limiting groove 221, making it impossible to prevent relative rotation between the first plastic part 3 and the pole post 2 through the cooperation of the limiting boss 32 and the limiting groove 221. If t is greater than 0.8 mm, the recess depth of the limiting groove 221 is too large, resulting in the remaining solid part on the base plate 22 along the Z direction corresponding to the limiting groove 221 being too thin, with poor structural strength, and prone to cracking and other problems during use. Therefore, by limiting t to a value within the range of 0.3 mm to 0.8 mm, the limiting groove 221 has a reasonable recess depth, which can ensure that the limiting groove 221 can stably cooperate with the limiting boss 32, preventing relative rotation between the pole post 2 and the first plastic part 3, thereby improving the torsional resistance of the pole post 2, and also ensure that the base plate 22 of the pole post 2 has sufficient structural strength, thereby improving the reliability and service life of the pole post 2.

[0087] Optionally, the value of t is any one of 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, or a value between any two of these values.

[0088] In one embodiment, the thickness T of the base plate 22 along the Z direction ranges from 1.5 mm to 2.5 mm. If T is less than 1.5 mm, the thickness of the base plate 22 is too small, resulting in insufficient structural strength. The base plate 22 is prone to deformation during cell use, affecting the reliability and safety of the cover assembly and the cell. Furthermore, the base plate 22 needs to be welded to the electrode tabs or connecting pieces of the electrode assembly, and the welding heat can easily penetrate the base plate 22 and melt the first plastic part 3, causing defects. If T is greater than 2.5 mm, the base plate 22 is too thick, resulting in excessive weight and cost, and it will occupy too much internal space of the cell along the Z direction, affecting the improvement of the cell's energy density. Therefore, by limiting T to the range of 1.5 mm to 2.5 mm, the structural strength of the base plate 22 itself can be guaranteed, preventing deformation and damage during use, improving the reliability and safety of the cover assembly and the cell. At the same time, the weight of the electrode post 2 can be avoided, reducing costs and preventing the base plate 22 from occupying too much internal space of the cell, thereby contributing to improving the energy density of the cell.

[0089] Optionally, the value of T is any one of 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.5 mm, or a value between any two of them.

[0090] In one embodiment, further combination Figures 8 to 10 , Figures 15 to 17 As shown, the upper surface of the cover plate body 1 is provided with a groove 13. The groove 13 includes a plurality of groove segments 131 arranged circumferentially around the first center line. Each groove segment 131 is connected between two adjacent limiting holes 12. The first plastic part 3 also includes a plurality of reinforcing parts 33. The reinforcing parts 33 are fixedly connected to the lower surface of the plastic part body 31. Each reinforcing part 33 is connected between two adjacent limiting bosses 32. The reinforcing parts 33 are located in the groove 13.

[0091] It should be noted that the groove 13 is formed by a portion of the upper surface of the cover plate body 1 recessed downward along the Z direction. Several grooves 13 are distributed at intervals along the circumference of the pole hole. The grooves 13 do not penetrate the cover plate body 1, while the limiting hole 12 penetrates the cover plate body 1. The circumferential edge of the cover plate body 1 surrounding the pole hole 11 has a structure in which the limiting hole 12, the groove segment 131, the limiting hole 12, and the groove segment 131 are distributed alternately in sequence. Each groove segment 131 is connected between two adjacent limiting holes 12. The groove segment 131 provides space for the reinforcing part 33 on the first plastic part 3. Each groove segment 131 corresponds to one reinforcing part 33. The dimension of the reinforcing part 33 along the Z direction is smaller than the dimension of the limiting boss 32 along the Z direction.

[0092] By providing a groove 13 on the upper surface of the cover plate body 1, and the groove 13 including several groove segments 131 that are alternately distributed with several limiting holes 12 along the circumferential direction, the groove 13 provides space for the reinforcing part 33. The reinforcing part 33 is connected to the root of two adjacent limiting bosses 32 to strengthen the structural strength of the root of the limiting bosses 32, thereby improving the structural strength of the limiting bosses 32 and preventing the limiting bosses 32 from breaking from the root when there is a relative rotation tendency between the first plastic part 3 and the cover plate body 1, thereby improving the reliability of the limiting bosses 32 and ensuring the torsional resistance of the first plastic part 3. Furthermore, by providing a groove 13 to accommodate the reinforcing part 33, the reinforcing part 33 is prevented from being directly supported on the upper surface of the cover plate body 1, thereby ensuring that the lower surface of the plastic part body 31 is tightly fitted with the upper surface of the cover plate body 1, improving the sealing between the first plastic part 3 and the cover plate body 1, and increasing the connection area between the first plastic part 3 and the cover plate body 1, thereby enhancing the tensile strength of the cover plate assembly along the Z direction. The term "root" refers to the part where the limiting boss 32 connects to the plastic body 31, that is, the end of the limiting boss 32 that is close to the plastic body 31 along the Z direction.

[0093] In one embodiment, the ring containing the groove 13 is designated as the second ring, and the groove segment 131 is a portion of the second ring. The radial width of the first ring is smaller than the radial dimension of the limiting hole 12. This ensures sufficient space for the reinforcement 33 while minimizing excessive damage to the cover plate body 1 structure, thereby guaranteeing the reliability of the cover plate assembly. It is understood that, as an alternative implementation, the radial width of the first ring can also be equal to or greater than the radial dimension of the limiting hole 12.

[0094] In one embodiment, further combination Figure 4 and Figure 15 As shown, the dimension of the reinforcing part 33 along the Z direction is b, and the dimension difference between the limiting boss 32 and the reinforcing part 33 along the Z direction is a; where b and a satisfy the relationship: 0.25≤b / a≤0.65; the units of b and a are both mm. If b / a is less than 0.25, then along the Z direction, the size of the reinforcing part 33 relative to the limiting boss 32 is too small, and the reinforcing effect of the reinforcing part 33 on the structural strength of the limiting boss 32 is not obvious. If b / a is greater than 0.65, then the size of the reinforcing part 33 relative to the limiting boss 32 along the Z direction is too large. When the size of the limiting boss 32 along the Z direction is fixed, the size of the reinforcing part 33 along the Z direction will be too large. Correspondingly, the recess depth of the groove 13 along the Z direction will be too large, and the thickness of the remaining solid part on the cover plate body 1 corresponding to the groove 13 will be too small, resulting in poor structural strength and poor reliability. Alternatively, when the size of the reinforcing part 33 along the Z direction is fixed, the size of the limiting boss 32 along the Z direction will be too small, and the fit size between the limiting boss 32 and the limiting groove 221 will be insufficient, and the pole post will not meet the anti-torsion requirements. Therefore, by limiting b / a to a value within the range of 0.25 to 0.65, it is possible to ensure that the reinforcing part 33 has sufficient structural reinforcement effect on the limiting boss 32, improve the reliability of the first plastic part 3, and ensure the torsional resistance of the first plastic part 3 and the pole post 2. At the same time, it is possible to avoid the reinforcing part 33 being too large in the Z direction, which would result in an excessively large recess depth of the groove 13. This ensures that the cover plate body 1 has sufficient structural strength and improves the reliability of the cover plate assembly.

[0095] Optionally, the value of b / a is any one of 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65 or a value between any two values.

[0096] In one embodiment, the value of 'a' ranges from 1.0 mm to 1.8 mm. It should be noted that after the limiting boss 32 passes through the pole hole 11 along the Z-direction and inserts into the limiting groove 221, if 'a' is less than 1.0 mm, the downward protrusion of the limiting boss 32 relative to the reinforcing part 33 along the Z-direction is too small. This may result in an insufficient overall dimension of the limiting boss 32 along the Z-direction, leading to insufficient insertion length between the limiting boss 32 and the limiting groove 221 along the Z-direction. The limiting boss 32 may easily detach from the limiting groove 221, failing to provide effective circumferential limiting and thus failing to prevent relative rotation between the pole 2 and the first plastic part 3, thereby compromising the torsional resistance of the pole 2. If 'a' is greater than 1.8 mm... If the size of the limiting boss 32 protruding downward relative to the reinforcing part 33 in the Z direction is too large, the overall size of the limiting boss 32 in the Z direction is too large, the structural strength of the limiting boss 32 in the Z direction is insufficient, the lower end of the limiting boss 32 away from the plastic body 31 in the Z direction is prone to deformation, and the insertion stability of the limiting boss 32 and the limiting groove 221 cannot be guaranteed.

[0097] Therefore, by limiting the value of 'a' to the range of 1.0 mm to 1.8 mm, the limiting boss 32 protrudes downward relative to the reinforcing part 33 by a reasonable size in the Z direction. This can avoid insufficient insertion fit between the limiting boss 32 and the limiting groove 221 in the Z direction, and also ensure that the limiting boss 32 has sufficient structural strength. This ensures a stable fit between the limiting boss 32 and the limiting groove 221, prevents the limiting boss 32 from coming out of the limiting groove 221, and prevents the pole post 2 from rotating relative to the first plastic part 3, thereby improving the torsional resistance of the pole post 2.

[0098] Optionally, the value of a is any one of 1.0 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, or a value between any two of them.

[0099] In one embodiment, the value of b is in the range of 0.4 mm ≤ b ≤ 0.8 mm. If b is less than 0.4 mm, the size of the reinforcing part 33 along the Z direction is too small, resulting in insufficient structural strength and an insignificant strengthening effect on the structural strength of the limiting boss 32. If b is greater than 0.8 mm, the size of the reinforcing part 33 along the Z direction is too large, leading to an excessively deep recess in the groove 13 along the Z direction and poor structural strength of the cover plate body 1. Therefore, by limiting b to a value within the range of 0.4 mm to 0.8 mm, it is possible to ensure that the reinforcing part 33 itself has sufficient structural strength, thereby ensuring the structural strengthening effect of the reinforcing part 33 on the limiting boss 32, improving the reliability of the first plastic part 3, and ensuring the torsional resistance of the first plastic part 3 and the pole post 2. At the same time, it is possible to avoid the reinforcing part 33 being too large along the Z direction, which would result in an excessively deep recess in the groove 13, thereby ensuring that the cover plate body 1 has sufficient structural strength and improving the reliability of the cover plate assembly.

[0100] In one embodiment, the column 21 has a second centerline extending along the Z direction and an outer peripheral surface radially away from the second centerline. An annular groove 211 surrounding the second centerline is formed on the outer peripheral surface of the column 21. The annular groove 211 is formed by a radially recessed portion of the outer peripheral surface of the column 21. The plastic body 31 is annular, and the first plastic part 3 further includes a first protruding ring 34. The first protruding ring 34 is fixedly connected to the inner ring of the plastic body 31 and is inserted into the annular groove 211. It should be noted that the orthographic projection of the plastic body 31 along the Z direction in the XY plane is annular. A first through hole 301 is formed on the inner side of the inner ring of the plastic body 31. The column 21 of the pole post 2 passes through the first through hole 301. The plastic body 31 has an inner wall radially facing the centerline of the first through hole 301, and the first protruding ring 34 is connected to the inner wall of the plastic body 31. By opening an annular groove 211 on the outer circumferential surface of the column 21 and setting a first protruding ring 34 on the inner annular wall of the plastic body 31, the first protruding ring 34 is inserted into the annular groove 211, thereby achieving mutual positioning between the first plastic part 3 and the pole post 2 along the pole post axis, ensuring the relative stability between the pole post 2 and the first plastic part 3 along the axis, and improving the reliability of the cover plate assembly.

[0101] In one embodiment, the first plastic part 3 is injection molded between the electrode post 2 and the cover plate body 1. The injection molding method is relatively simple. The first plastic part 3 can connect the electrode post 2 and the cover plate body 1 at the same time, and ensure the insulation and sealing between the electrode post 2 and the cover plate body 1. This eliminates the use of the riveting block in the traditional battery cell, reduces costs, and improves production efficiency.

[0102] In one embodiment, further combination Figure 4 , Figure 16 and Figure 19As shown, the first plastic part 3 also includes a second protruding ring 35, which is fixedly connected to the lower side of the plastic part body 31 and connected to the side of the limiting boss 32 facing the first through hole 301 in the radial direction; the column 21 also includes a third protruding ring 212, which is located at one end of the column 21 along the Z direction near the bottom plate 22. The third protruding ring 212 protrudes radially from the outer circumferential surface of the column 21, and the lower surface of the second protruding ring 35 abuts against the upper surface of the third protruding ring 212; the second protruding ring 35 fills the gap between the column 21 and the hole wall of the pole hole 11. The dimension of the second protruding ring 35 along the Z direction is larger than the dimension of the reinforcing part 33 along the Z direction. The second protruding ring 35 can further strengthen the structural strength of the limiting boss 32 and ensure the insulation and sealing between the pole 2 and the cover plate body 1. It is understood that, as an alternative implementation, the pole post 2 may not have the third convex ring 212 provided, and the lower surface of the second convex ring 35 may be directly attached to the upper surface of the base plate 22, which can also achieve the above function, and will not be described in detail here.

[0103] Specifically, the dividing lines of the plastic body 31, the limiting boss 32, the first protruding ring 34, and the second protruding ring 35 of the first plastic part 3 are as follows: Figure 19 The dashed lines in the diagram are for illustrative purposes only.

[0104] In one embodiment, the cover assembly further includes a second plastic part 4, which is disposed on the lower side of the cover body 1 to ensure insulation between the cover body 1 and the electrode group inside the battery cell. The second plastic part 4 has a second through hole corresponding to the electrode post hole 11, and the post 21 passes through the second through hole. The base plate 22 is located below the second plastic part 4, and at least a portion of the second plastic part 4 extends into the gap between the base plate 22 and the cover body 1 to ensure insulation between the base plate 22 and the cover body 1. Here, "lower side" refers to the lower side along the Z-direction, that is, the side of the cover body 1 pointing towards the inner cavity of the housing along the Z-direction. It should be noted that the opening shape of the second through hole is adapted to the shape of the electrode post hole 11 plus the limiting hole 12 to ensure that the limiting boss 32 can pass through the second plastic part 4 and engage with the limiting groove 221.

[0105] Optionally, the cover plate body 1 is made of plain aluminum plate.

[0106] The assembly process of the cover plate assembly in this embodiment is as follows:

[0107] The electrode post 2, cover plate body 1, and second plastic part 4 are sequentially placed into the plastic mold for positioning. The mold positioning method restricts the electrode post 2, cover plate body 1, and second plastic part 4 to the designated position. Then, the first plastic part 3 is molten and injected into the gap between the electrode post 2 and cover plate body 1 through injection molding. After cooling, insulation and sealing connection are achieved, which solves the problem that traditional battery cells need to add additional riveting blocks, reduces costs, and improves production efficiency.

[0108] In this embodiment, the cover plate assembly is fixedly installed between the cover plate body 1 and the pole post 2 by injection molding a first plastic part 3. This solves the problem of needing to add additional riveting blocks, reduces costs, improves production efficiency, and ensures the tight fit between the first plastic part 3, the pole post 2, and the cover plate body 1, thus guaranteeing sealing performance. Furthermore, the cover plate body 1 has several limiting holes 12 that surround the pole post hole 11 in the circumferential direction, and the bottom plate 22 of the pole post 2 has limiting grooves 221 corresponding to the limiting holes 12. The first plastic part 3 is injection molded... Several limiting bosses 32 protrude along the Z-direction from the lower surface of the plastic body 31. The limiting bosses 32 are simultaneously inserted into the limiting holes 12 and the limiting grooves 221, thereby achieving circumferential limiting between the first plastic part 3 and the cover plate body 1 and the pole post 2, preventing relative rotation between the first plastic part 3 and the cover plate body 1 and between the first plastic part 3 and the pole post 2, thus preventing relative rotation between the pole post 2 and the cover plate body 1, improving the torsional resistance of the pole post 2 and the first plastic part 3, and ensuring the sealing performance and safety of the product.

[0109] According to an embodiment of the present invention, in another aspect, a battery cell is also provided, comprising: a housing, an electrode assembly, and the aforementioned cover plate assembly. The housing has an open end; the electrode assembly is disposed inside the housing; and the cover plate assembly covers the open end of the housing. Optionally, the battery cell is a lithium-ion battery cell.

[0110] The following examples and comparative examples verify the impact of different parameter values ​​on the performance of the cover plate assembly. The parameter settings for the examples and comparative examples are shown in Table 1, and the corresponding verification results are shown in Table 2.

[0111] Table 1

[0112]

[0113] Table 2

[0114]

[0115] In Table 1, the "√" in the column containing "d+0.5mm≤D≤d+2mm" indicates that d and D satisfy the relationship d+0.5mm≤D≤d+2mm, while "×" indicates that d and D do not satisfy the relationship d+0.5mm≤D≤d+2mm.

[0116] As can be seen from Tables 1 and 2, for the cover plate assemblies of Embodiments 1 to 6, all parameters are within the range defined in this application. The structural design of each component of the product is reasonable. Specifically: 1. The limiting hole on the cover plate body and the limiting boss of the first plastic part form an undercut, enhancing the connection strength and torsional strength of the product; 2. The structural strength of the limiting boss is further improved due to the presence of the reinforcing part, and the connection area between the first plastic part and the cover plate body is increased, enhancing the tensile strength of the product in the Z direction; 3. The correlation between the pole and the first plastic part is enhanced, improving the torsional strength of the pole. The overall product design meets the requirements for torsional and tensile strength, is easy to process and manufacture, and has a low cost. It is evident that when the parameters of the cover plate assembly are within the range defined in this application, the cover plate assembly performs well.

[0117] For the cover plate assembly of Comparative Example 1, the value of b / a is 0.8, which is greater than the upper limit of b / a of 0.65 defined in this application and is not within the range defined in this application. The dimensions of the reinforcing part and the groove along the Z direction are too large, resulting in the thickness of the remaining solid part after the groove is opened on the cover plate body being too small, and the structural strength of the cover plate body being too poor; or the dimension of the limiting boss along the Z direction is too small, and it cannot be effectively inserted with the limiting groove. The limiting boss is very easy to come out of the limiting groove, and the pole cannot meet the anti-torsion requirements.

[0118] For the cover plate assembly of Comparative Example 2, the t / T value is 0.65, which is greater than the upper limit of t / T of 0.5 defined in this application and is not within the range defined in this application. The limiting groove on the pole post has a deep recess along the Z direction. The base plate structure is not strong enough and is very easy to break. When the base plate is welded to the pole lug or connecting piece, the welding heat can easily penetrate the base plate and melt the first plastic part, causing defects.

[0119] For the cover plate assembly of Comparative Example 3, the difference between D and d is 3mm, D>d+2mm, which is not within the range defined in this application. Furthermore, the end face difference between the limiting boss and the reinforcing part along the Z direction is large, and the limiting boss is relatively high, making it extremely easy to break. The limiting groove on the pole post is shallow, and the pole post cannot meet the anti-torsion requirements.

[0120] Unless otherwise stated, the values ​​of all parameters mentioned in this application can be determined using testing methods commonly used in the art. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0121] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate body has an pole post hole and several limiting holes. The several limiting holes are arranged circumferentially around the pole post hole. Both the pole post hole and the limiting holes penetrate the cover plate body along the Z direction. The pole post includes a column body and a base plate. The column body passes through the pole post hole, and the base plate is located on the lower side of the cover plate body along the Z direction. The base plate has a limiting groove corresponding to the limiting hole. The first plastic part includes a plastic part body and a plurality of limiting bosses. The plastic part body is sleeved on the column. The limiting bosses are fixedly connected to the lower surface of the plastic part body along the Z direction. The plurality of limiting bosses correspond one-to-one with the plurality of limiting holes. Each limiting boss is inserted into the corresponding limiting hole and the limiting groove. The limiting groove is formed by a portion of the upper surface of the base plate recessed along the Z direction. The recess depth of the limiting groove along the Z direction is t, and the thickness of the base plate along the Z direction is T. The relationship between t and T is: 0.15≤t / T≤0.

5.

2. The cover plate assembly according to claim 1, characterized in that, The pole post hole has a first center line extending along the Z direction, and the limiting hole is formed by a portion of the hole wall of the pole post hole being recessed radially away from the first center line.

3. The cover plate assembly according to claim 2, characterized in that, The limiting hole is an arc-shaped hole, and the orthographic projection of the arc-shaped hole along the Z direction in the XY plane has an opening side that is radially close to the first center line and a first arc segment that is radially away from the first center line. The arc length D of the first arc segment, and the arc length d of the opening side along the circumference of the pole hole in the XY plane, wherein D and d satisfy the following relationship: d+0.5mm≤D≤d+2mm; and / or, the value range of d is: 3 mm≤d≤8 mm; and / or, the value range of D is: 3.5 mm≤D≤10 mm; And / or, the radial dimension of the arc-shaped hole is H, wherein 0.8 mm ≤ H ≤ 3.2 mm.

4. The cover plate assembly according to claim 1, characterized in that, The number of limiting holes is N, where 2≤N≤30, and N is a positive integer.

5. The cover plate assembly according to claim 1, characterized in that, The recess depth t of the limiting groove along the Z direction ranges from 0.3 mm to 0.8 mm. And / or, the thickness T of the base plate along the Z direction is in the range of 1.5 mm ≤ T ≤ 2.5 mm.

6. The cover plate assembly according to claim 2, characterized in that, The upper surface of the cover plate body is provided with a groove, the groove including a plurality of groove segments arranged circumferentially around the first center line, each groove segment being connected between two adjacent limiting holes; the first plastic part also includes a plurality of reinforcing parts, the reinforcing parts being fixedly connected to the lower surface of the plastic part body, each reinforcing part being connected between two adjacent limiting bosses, and the reinforcing parts being located in the groove.

7. The cover plate assembly according to claim 6, characterized in that, The dimension of the reinforcing part along the Z direction is b, and the dimension difference between the limiting boss and the reinforcing part along the Z direction is a; Wherein, b and a satisfy the following relationship: 0.25≤b / a≤0.65; and / or, the value range of a is: 1.0 mm≤a≤1.8 mm; and / or, the value range of b is: 0.4 mm≤b≤0.8 mm.

8. The cover plate assembly according to claim 1, characterized in that, The column has a second center line extending along the Z direction and an outer peripheral surface that is radially away from the second center line. An annular groove surrounding the second center line is formed on the outer peripheral surface of the column. The plastic body is annular in shape. The first plastic part also includes a first protruding ring, which is fixedly connected to the inner ring of the plastic body and inserted into the annular groove.

9. The cover plate assembly according to any one of claims 1 to 8, characterized in that, The first plastic part is injection molded between the pole post and the cover plate body.

10. A battery cell, characterized in that, include: The shell has an open end; The electrode assembly is placed inside the housing; The cover assembly according to any one of claims 1 to 9 is provided covering the opening end of the housing.

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