Top cover assembly and battery cell

Abstract

The utility model relates to battery technical field discloses top cover subassembly and electric core, top cover subassembly, include: apron has mounting hole, pole, including first column section and second column section, first column section is worn in mounting hole, the outer diameter of second column section is greater than the inner diameter of mounting hole, connecting piece is seted up with along the assembly hole of thickness direction through arrangement, second column section is inserted in assembly hole, and the outer peripheral edge of second column section and the inner peripheral edge of connecting piece around assembly hole are welded, sealing element, compression setting between pole and apron, the utility model second column section of pole can be connected with the inner wall of assembly hole through the welding mode of seam welding, can promote effective welding penetration, can more directly confirm the contact surface welding quality, in addition, sealing element compression setting between pole and apron, when pole and connecting piece connection produce slack or separate, sealing element still can keep its sealing function, can avoid the situation of sealing failure.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a top cover assembly and a battery cell. Background Technology

[0002] In the current lithium-ion battery field, the connecting tabs within the battery function to connect the tabs and terminals of the cell, thereby enabling current conduction within the cell. During cell assembly, the terminals pass through the mounting holes on the cover plate and connect to the connecting tabs; the terminals and connecting tabs are primarily connected by welding.

[0003] Currently, existing poles and connecting pieces are mainly connected by through welding. One end face of the pole and one side of the connecting piece are welded through by welding laser. In order to improve the sealing performance of the connection position, a sealing ring is usually fitted on the outside of the pole, and one side of the connecting piece abuts against the wall of the cover plate through the sealing ring.

[0004] When the connection between the electrode post and the connecting piece becomes loose, it will affect the sealing effect of the sealing ring and easily lead to leakage. Utility Model Content

[0005] In view of this, the present invention provides a top cover assembly and a battery cell to solve the problem of poor reliability of the sealing method of existing terminals and connecting pieces.

[0006] In a first aspect, this utility model provides a top cover assembly, comprising: a cover plate having a mounting hole extending through the thickness direction; an electrode post including a first post segment and a second post segment connected along the thickness direction, the first post segment passing through the mounting hole, and the outer diameter of the second post segment being larger than the inner diameter of the mounting hole; a connecting piece disposed on one side of the cover plate along the thickness direction, the connecting piece having an assembly hole extending through the thickness direction, the second post segment being inserted into the assembly hole, the outer peripheral edge of the second post segment away from the first post segment being a first connecting position, the inner peripheral edge of the connecting piece surrounding the assembly hole being a second connecting position, the first connecting position being welded to the second connecting position; and a sealing member sleeved on the outer periphery of the first post segment and abutting against the side of the second post segment facing the first post segment, the sealing member being compressed between the electrode post and the cover plate.

[0007] Beneficial effects: By setting an assembly hole on the connecting piece, the second column section of the pole can be connected to the inner wall of the assembly hole by seam welding after passing through the assembly hole. This not only improves the effective weld penetration, but also reduces obstruction in the welding area, allowing for more intuitive confirmation of the welding quality of the contact surface, thus ensuring the stability and reliability of the weld. In addition, since the outer diameter of the second column section is larger than the inner diameter of the mounting hole, the seal is compressed between the pole and the cover plate. Even if the connection between the pole and the connecting piece becomes loose or separates, the seal can still maintain its sealing function, effectively preventing seal failure and effectively solving the problem of poor reliability of the existing sealing method between the pole and the connecting piece.

[0008] In one optional embodiment, the second column segment includes a first mating segment and a second mating segment arranged along the thickness direction. The first mating segment is connected between the first column segment and the second mating segment, and the second mating segment is inserted into the assembly hole. The outer diameter of the first mating segment is larger than the outer diameter of the second mating segment, so that the outer periphery of the first mating segment extends out of the second mating segment. The portion of the first mating segment extending out of the second mating segment forms an abutting surface facing the second mating segment, and the abutting surface abuts against the side of the connecting piece facing the cover plate.

[0009] Beneficial effects: The first mating section can be positioned by abutting with the connecting piece, which can improve the assembly accuracy and installation convenience of the second column section and the assembly hole. In addition, since the outer diameter of the first mating section is larger than that of the second mating section, the first mating section can form a flange structure. When the second mating section is welded to the assembly hole, the first mating section can block the welding laser, avoiding light leakage during welding and preventing damage to the seal or cover plate by the laser. This can effectively improve the safety and reliability of the welding process.

[0010] In one optional embodiment, the outer diameter of the second mating section is R1, with a value ranging from 12mm to 40mm, and the outer diameter of the first column section is R2, with a value ranging from 6mm to 16mm.

[0011] Beneficial effects: This type of pole, while ensuring its own connection strength, also has good current-carrying capacity after being connected with the connecting piece.

[0012] In one optional embodiment, the height of the second mating section along the thickness direction is H1, and the value of H1 ranges from 0.5 mm to 2.5 mm; and / or, the height of the first mating section along the thickness direction is H2, and the value of H2 ranges from 0.5 mm to 2 mm.

[0013] Beneficial effects: The second column has a simple and reliable structure. By limiting the thickness of the second column, the effective welding depth and connection strength can be guaranteed. At the same time, the current carrying capacity can be met after the pole and the connecting piece are connected.

[0014] In one optional embodiment, the outer diameter of the first mating section is R3, and the outer diameter R3 of the first mating section and the outer diameter R1 of the second mating section satisfy R3-R1≥0.5mm.

[0015] Beneficial effects: It facilitates processing while ensuring the area of ​​the contact surface, making the force more even when the contact surface and the wall of the connecting piece are in contact.

[0016] In one optional embodiment, the connecting piece includes a piece body and a boss. The side of the piece body near the cover plate is a first wall surface. The boss is fixedly disposed on the first wall surface and arranged around the assembly hole. The inner ring wall surface of the boss is welded and fixed to the outer peripheral surface of the first mating section. The end face of the boss near the cover plate abuts and engages with the abutting surface.

[0017] Beneficial effects: This type of connecting piece, with its boss, can improve the structural strength at the assembly hole. At the same time, the inner ring wall of the boss is welded and fixed to the outer peripheral surface of the first mating section, which can further increase the effective welding depth between the connecting piece and the first mating section, reduce the resistance at the assembly hole, improve the current efficiency, and reduce the temperature rise during operation.

[0018] In one optional embodiment, the thickness of the sheet is T1, the thickness of the boss is T2, and the height H1 of the second mating section satisfies H1=T1+T2.

[0019] Beneficial effects: By adopting this dimensional relationship, the height of the second mating section can be standardized and fixed in the future. During the design, the size of the pole is fixed, and the thickness of the sheet can be flexibly adjusted according to the different overcurrent of the cell. Subsequently, the thickness of the boss is adjusted according to the thickness of the sheet so that the thickness relationship satisfies H1=T1+T2. At this time, the overcurrent capacity can be adjusted while ensuring that the effective welding depth between the connecting piece and the pole remains unchanged, which can reduce the research and development and production costs.

[0020] In one optional embodiment, the first column segment includes a third mating segment, a fourth mating segment, and a fifth mating segment arranged along the thickness direction. The third mating segment is connected between the fourth mating segment and the second column segment, and the fourth mating segment is connected between the third mating segment and the fifth mating segment. The third mating segment is inserted into the mounting hole, and the outer diameters of the third mating segment and the fifth mating segment are both larger than the outer diameter of the fourth mating segment. The top cover assembly also includes a riveting component located on the side of the cover plate away from the connecting piece. The riveting component has a riveting hole that runs through the thickness direction. The riveting hole includes a first hole segment and a second hole segment arranged in a direction away from the third mating segment. The inner diameter of the second hole segment is larger than the inner diameter of the first hole segment. The outer diameters of the third mating segment and the fifth mating segment are both larger than the inner diameter of the first hole segment. The fourth mating segment is inserted into the first hole segment, and the fifth mating segment is inserted into the second hole segment. The fifth mating segment is riveted to the riveting component.

[0021] Beneficial effects: The connection between the riveted part and the first column section is simple and reliable, and the third and fifth mating sections can effectively limit the displacement of the riveted part along the thickness direction.

[0022] In one alternative implementation, the end face of the second column segment away from the first column segment is flush with the end face of the connecting piece away from the cover plate.

[0023] Beneficial effect: This type of fit can further ensure the quality of the weld between the second column segment and the connecting piece.

[0024] Secondly, this utility model also provides a battery cell, which includes: a housing having an internal cavity and an opening communicating with the cavity on one side; a battery cell disposed in the cavity, the battery cell including a tab; and the aforementioned top cover assembly disposed at the opening of the housing and connected to the housing, the connecting piece being electrically connected to the tab. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a cross-sectional view of a top cover assembly according to an embodiment of the present utility model; Figure 2 for Figure 1 A partially enlarged schematic diagram of the top cover assembly shown; Figure 3 for Figure 1 An exploded view of the pole and connecting piece of the top cover assembly shown; Figure 4 for Figure 1 The diagram shows a cross-sectional view of the pole and connecting piece of the top cover assembly; Figure 5 for Figure 1 The front view of the pole of the top cover assembly shown; Figure 6 for Figure 1 The front view of the connecting piece of the top cover assembly shown.

[0027] Explanation of reference numerals in the attached figures: 1. Cover plate; 101. Mounting hole; 2. Pole post; 201. First column segment; 2011. Third joint segment; 2012. Fourth joint segment; 2013. Fifth joint segment; 202. Second column segment; 2021. First mating segment; 2022. Second mating segment; 2023. Abutment surface; 203. Stepped surface; 3. Connecting piece; 301. Piece body; 3011. Assembly hole; 3012. First wall surface; 302. Boss; 4. Sealing components; 5. Riveting component; 501. Riveting hole; 5011. First hole section; 5012. Second hole section. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0030] The electrode and connecting piece are welded through by welding laser. Although this connection method can fix the electrode and connecting piece, the effective penetration depth of the through welding is small and the welding quality is difficult to confirm. As a result, the assembled battery cell is prone to insufficient overcurrent capacity during operation.

[0031] In related technologies, one end face of the pole and one side face of the connecting piece are welded through a welding laser. However, since the connecting piece will block the welding position, the state of the welding position after the two parts are welded cannot be observed and confirmed, and there are often cases of incomplete welding. Therefore, this connection method also has the problem of not being able to confirm the connection quality between the pole and the connecting piece.

[0032] According to an embodiment of the present invention, a top cover assembly is provided, comprising: a cover plate 1, a pole post 2, a connecting piece 3, and a sealing element 4. The cover plate 1 has a mounting hole 101 extending through the thickness direction; the pole post 2 includes a first pole segment 201 and a second pole segment 202, which are connected along the thickness direction. The first pole segment 201 passes through the mounting hole 101, and the outer diameter of the second pole segment 202 is larger than the inner diameter of the mounting hole 101; the connecting piece 3 is disposed on one side of the cover plate 1 along the thickness direction. An assembly hole 3011 is provided through the thickness direction. The second column segment 202 is inserted into the assembly hole 3011. At the end of the second column segment 202 away from the first column segment 201, the outer peripheral edge of the second column segment 202 is the first connection position. The connecting piece 3 surrounds the inner peripheral edge of the assembly hole 3011 as the second connection position. The first connection position and the second connection position are welded together. The sealing member 4 is sleeved on the outer periphery of the first column segment 201 and abuts against the side of the second column segment 202 facing the first column segment 201. The sealing member 4 is compressed between the pole post 2 and the cover plate 1.

[0033] It should be noted that, in this embodiment, the thickness direction is... Figure 2 The thickness direction indicated by the middle arrow.

[0034] In the top cover assembly of this embodiment, an assembly hole 3011 is provided on the connecting piece 3. After the second column segment 202 of the pole post 2 passes through the assembly hole 3011, it can be connected to the inner wall of the assembly hole 3011 by seam welding. This can improve the effective weld penetration and reduce obstruction in the welding area, allowing for more intuitive confirmation of the welding quality of the contact surface, thus ensuring the stability and reliability of the welding. In addition, since the outer diameter of the second column segment 202 is larger than the inner diameter of the mounting hole 101, the seal 4 is compressed and disposed between the pole post 2 and the cover plate 1. Even if the connection between the pole post 2 and the connecting piece 3 becomes loose or separates, the seal 4 can still maintain its sealing function, effectively preventing the occurrence of seal failure and effectively solving the problem of poor reliability of the existing sealing method between the pole post and the connecting piece.

[0035] The outer diameter of the second column segment 202 is larger than the outer diameter of the first column segment 201, and the inner diameter of the mounting hole 101 is larger than the outer diameter of the first column segment 201. This dimensional relationship allows the first column segment 201 to be smoothly inserted into the mounting hole 101.

[0036] Specifically, such as Figure 2As shown, the sealing element 4 includes a first sealing section and a second sealing section connected together. The first sealing section is compressed between the upper end face of the second column 202 and the lower end face of the cover plate 1. The second sealing section is compressed between the outer peripheral surface of the first column 201 and the inner wall of the mounting hole 101. This type of sealing element 4 can form a multi-layer sealing structure, which can improve the sealing reliability and also make the pole post 2 more stably installed in the mounting hole 101.

[0037] It should be noted that in this embodiment, "up" and "down" refer to... Figure 2 The middle arrow indicates the top and bottom of the thickness direction.

[0038] Furthermore, since the electrode post 2 and the connecting piece 3 are welded together after being inserted, the space occupied by the electrode post 2 and the connecting piece 3 in the internal space of the cell can be effectively reduced, the height of the cell inside the battery can be increased, and thus the overall capacity and energy density of the battery can be increased.

[0039] In one possible implementation, such as Figure 2 and Figure 4 As shown, the second column segment 202 includes a first mating segment 2021 and a second mating segment 2022 arranged along the thickness direction. The first mating segment 2021 connects the first column segment 201 and the second mating segment 2022. The second mating segment 2022 is inserted into the assembly hole 3011. The outer diameter of the first mating segment 2021 is larger than the outer diameter of the second mating segment 2022, so that the outer periphery of the first mating segment 2021 extends out of the second mating segment 2022. The portion of the first mating segment 2021 extending out of the second mating segment 2022 forms an abutment surface 2023 facing the second mating segment 2022. The abutment surface 2023 and the connecting... The connecting piece 3 is positioned to abut against the side of the cover plate 1. The first mating section 2021 and the connecting piece 3 can be positioned by abutting against each other, which can improve the assembly accuracy and installation convenience of the second column section 202 and the assembly hole 3011. In addition, since the outer diameter of the first mating section 2021 is larger than the outer diameter of the second mating section 2022, the first mating section 2021 can form a flange structure. When the second mating section 2022 is welded to the assembly hole 3011, the first mating section 2021 can block the welding laser, avoiding light leakage during welding and preventing the seal 4 or the cover plate 1 from being damaged by the laser. This can effectively improve the safety and reliability of the welding process.

[0040] Specifically, since there is usually a plastic part between the cover plate 1 and the connecting piece 3, if the first column 201 is not provided, when the welding laser is welded along the thickness direction, it is easy to shine directly towards the cover plate 1, causing the plastic part to melt locally or even boil over, which can easily cause the laser welding to explode. The second column 202 in this embodiment can effectively solve this welding problem.

[0041] In one possible implementation, such as Figure 6 As shown, the outer diameter of the second mating section 2022 is R1, and the value of R1 ranges from 12mm to 40mm. The outer diameter of the first column section 201 is R2, and the value of R2 ranges from 6mm to 16mm. This type of pole 2, while ensuring its own connection strength, also has good current-carrying capacity after being connected with the connecting piece 3.

[0042] It should be noted that since the outer diameter of the second column segment 202 is greater than the outer diameter of the first column segment 201, when R1 is 12mm, the value of R2 must be less than 12mm. The range of values ​​here is the optional range of R1 and R2, and does not mean that it conflicts with the limitation that "the outer diameter of the second column segment 202 is greater than the outer diameter of the first column segment 201".

[0043] In addition, the outer diameter R1 of the second mating section 2022 exceeds the outer diameter R2 of the first column section 201 by a range of 6 mm to 24 mm.

[0044] Optionally, the value of R1 can be any one of 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, or 40mm, or a value between any two of these values.

[0045] Optionally, the value of R2 can be any value among 6mm, 8mm, 10mm, 12mm, 14mm, and 16mm, or a value between any two of these values.

[0046] In one possible implementation, such as Figure 5 As shown, the height of the second mating section 2022 along the thickness direction is H1, and the value of H1 ranges from 0.5mm to 2.5mm; the height of the first mating section 2021 along the thickness direction is H2, and the value of H2 ranges from 0.5mm to 2mm. The second column section 202 has a simple and reliable structure. By using the second column section 202, the effective welding depth and connection strength can be guaranteed. At the same time, the current carrying capacity can also be met after the pole 2 is connected to the connecting piece 3.

[0047] Specifically, the value of H1 can be any one of 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, 2.3mm, and 2.5mm, or a value between any two of these values. The value of H2 can be any one of 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, 1.7mm, and 2mm, or a value between any two of these values.

[0048] In one possible implementation, such as Figures 4 to 6As shown, the outer diameter of the first mating section 2021 is R3. The outer diameter R3 of the first mating section 2021 and the outer diameter R1 of the second mating section 2022 satisfy R3-R1≥0.5mm, which facilitates processing while ensuring the area of ​​the contact surface 2023, ensuring the stability and reliability of the contact fit between the contact surface 2023 and the connecting piece 3, avoiding stress concentration, and also ensuring the effectiveness of laser shielding.

[0049] In one possible implementation, such as Figure 3 and Figure 4 As shown, the connecting piece 3 includes a piece body 301 and a boss 302. The side of the piece body 301 near the cover plate 1 is a first wall surface 3012. The boss 302 is fixedly disposed on the first wall surface 3012 and surrounds the assembly hole 3011. The inner ring wall surface of the boss 302 is welded and fixed to the outer peripheral surface of the first mating section 2021. The end face of the boss 302 near the cover plate 1 abuts and engages with the abutting surface 2023. With this type of connecting piece 3, the boss 302 can not only improve the structural strength at the assembly hole 3011, but also further improve the effective welding depth between the connecting piece 3 and the first mating section 2021, which can reduce the resistance at the assembly hole 3011, improve the current efficiency, and reduce the temperature rise during operation.

[0050] Specifically, such as Figure 3 and Figure 4 As shown, the boss 302 has a first hole section 5011, and the sheet 301 has a second hole section 5012. The inner diameters of the first hole section 5011 and the second hole section 5012 are the same, and together they form the assembly hole 3011.

[0051] In one possible implementation, such as Figure 4 As shown, the thickness of the sheet 301 is T1, the thickness of the boss 302 is T2, and the height H1 of the second mating section 2022 satisfies H1=T1+T2. With this dimensional relationship, the height of the second mating section 2022 can be standardized and fixed in the future. During the design, the size of the pole post 2 is fixed, and the thickness of the sheet 301 can be flexibly adjusted according to the different overcurrent of the battery cell. Subsequently, the thickness of the boss 302 is adjusted according to the thickness of the sheet 301 so that the thickness relationship satisfies H1=T1+T2. At this time, the overcurrent capacity can be adjusted while ensuring that the effective welding depth between the connecting piece 3 and the pole post 2 remains unchanged, which can reduce the research and development and production costs.

[0052] Specifically, the thickness and height dimensions here are dimensions in the same direction.

[0053] In one possible implementation, the first column segment 201 includes a third mating segment 2011, a fourth mating segment 2012, and a fifth mating segment 2013 arranged along the thickness direction. The third mating segment 2011 is connected between the fourth mating segment 2012 and the second column segment 202. The fourth mating segment 2012 is connected between the third mating segment 2011 and the fifth mating segment 2013. The third mating segment 2011 is inserted into the mounting hole 101. The outer diameters of the third mating segment 2011 and the fifth mating segment 2013 are both larger than the outer diameter of the fourth mating segment 2012. The top cover assembly also includes a riveting member 5, which is located on the side of the cover plate 1 away from the connecting piece 3. The riveting member 5 has a riveting hole 501 that runs through the thickness direction. The riveting hole 501 includes a first hole section 5011 and a second hole section 5012 arranged in a direction away from the third mating section 2011. The inner diameter of the second hole section 5012 is larger than the inner diameter of the first hole section 5011. The outer diameters of the third mating section 2011 and the fifth mating section 2013 are both larger than the inner diameter of the first hole section 5011. The fourth mating section 2012 is inserted into the first hole section 5011, and the fifth mating section 2013 is inserted into the second hole section 5012. The fifth mating section 2013 is riveted to the riveting member 5.

[0054] The connection between the riveted part 5 and the first column section 201 is simple and reliable. The third mating section 2011 and the fifth mating section 2013 can effectively limit the displacement of the riveted part 5 along the thickness direction.

[0055] Specifically, the riveting component 5 is a metal component, and after the riveting component 5 is riveted to the first column segment 201, the electrical connection area of ​​the first column segment 201 can be effectively increased.

[0056] In one possible implementation, the inner wall of the boss 302 is chamfered at the end near the cover plate 1, which makes it easier for the pole post 2 to be inserted into the boss 302. At the same time, it can also reduce the stress concentration at the edge of the boss 302 and reduce the risk of the pole post 2 being damaged by colliding with the edge when inserted into the boss 302.

[0057] Specifically, there are no restrictions on the form of the chamfer; it can be either a rounded corner or a flat corner, and the choice can be made flexibly according to the requirements.

[0058] In one possible implementation, such as Figure 2 and Figure 4 As shown, the end face of the second column segment 202 away from the first column segment 201 is flush with the end face of the connecting piece 3 away from the cover plate 1. This kind of fit can further ensure the weld quality between the second column segment 202 and the connecting piece 3.

[0059] According to an embodiment of the present invention, in another aspect, a battery cell is provided, comprising: a housing, a battery cell, and the aforementioned top cover assembly, wherein the housing has an internal cavity and an opening communicating with the cavity on one side; the battery cell is disposed in the cavity and includes a tab; the top cover assembly is disposed at the opening of the housing and connected to the housing, and a connecting piece 3 is electrically connected to the tab.

[0060] Although embodiments of the present 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 present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A top cover assembly, characterized in that, include: The cover plate (1) has a mounting hole (101) that extends through the thickness direction. The pole post (2) includes a first column segment (201) and a second column segment (202). The first column segment (201) and the second column segment (202) are connected along the thickness direction. The first column segment (201) passes through the mounting hole (101). The outer diameter of the second column segment (202) is larger than the inner diameter of the mounting hole (101). A connecting piece (3) is disposed on one side of the cover plate (1) along the thickness direction. The connecting piece (3) has an assembly hole (3011) that is disposed through the thickness direction. The second column segment (202) is inserted into the assembly hole (3011). At the end of the second column segment (202) away from the first column segment (201), the outer peripheral edge of the second column segment (202) is the first connection position. The connecting piece (3) surrounds the inner peripheral edge of the assembly hole (3011) as the second connection position. The first connection position is welded to the second connection position. The sealing element (4) is sleeved on the outer periphery of the first column segment (201) and abuts against the side of the second column segment (202) facing the first column segment (201). The sealing element (4) is compressed between the pole post (2) and the cover plate (1).

2. The top cover assembly according to claim 1, characterized in that, The second column segment (202) includes a first mating segment (2021) and a second mating segment (2022) arranged along the thickness direction. The first mating segment (2021) is connected between the first column segment (201) and the second mating segment (2022). The second mating segment (2022) is inserted into the assembly hole (3011). The outer diameter of the first mating segment (2021) is larger than the outer diameter of the second mating segment (2022) so that the outer periphery of the first mating segment (2021) extends out of the second mating segment (2022). The portion of the first mating segment (2021) extending out of the second mating segment (2022) forms an abutment surface (2023) facing the second mating segment (2022). The abutment surface (2023) abuts against the side of the connecting piece (3) facing the cover plate (1).

3. The top cover assembly according to claim 2, characterized in that, The outer diameter of the second mating section (2022) is R1, and the value of R1 ranges from 12mm to 40mm. The outer diameter of the first column section (201) is R2, and the value of R2 ranges from 6mm to 16mm.

4. The top cover assembly according to claim 2, characterized in that, The height of the second mating section (2022) along the thickness direction is H1, and the value of H1 ranges from 0.5mm to 2.5mm; And / or, the height of the first mating segment (2021) along the thickness direction is H2, and the value of H2 ranges from 0.5mm to 2mm.

5. The top cover assembly according to claim 2, characterized in that, The outer diameter of the first mating section (2021) is R3, and the outer diameter R3 of the first mating section (2021) and the outer diameter R1 of the second mating section (2022) satisfy R3-R1≥0.5mm.

6. The top cover assembly according to any one of claims 4 to 5, characterized in that, The connecting piece (3) includes a piece body (301) and a boss (302). The side of the piece body (301) near the cover plate (1) is a first wall surface (3012). The boss (302) is fixedly disposed on the first wall surface (3012) and is disposed around the assembly hole (3011). The end face of the boss (302) near the cover plate (1) abuts against the abutting surface (2023).

7. The top cover assembly according to claim 6, characterized in that, The thickness of the sheet (301) is T1, the thickness of the boss (302) is T2, and the height H1 of the second mating section (2022) satisfies H1=T1+T2.

8. The top cover assembly according to claim 7, characterized in that, The first column segment (201) includes a third mating segment (2011), a fourth mating segment (2012), and a fifth mating segment (2013) arranged along the thickness direction. The third mating segment (2011) is connected between the fourth mating segment (2012) and the second column segment (202). The fourth mating segment (2012) is connected between the third mating segment (2011) and the fifth mating segment (2013). The third mating segment (2011) is inserted into the mounting hole (101). The outer diameters of the third mating segment (2011) and the fifth mating segment (2013) are both larger than the outer diameter of the fourth mating segment (2012). The top cover assembly also includes a riveting member (5), which is located on the side of the cover plate (1) away from the connecting piece (3). The riveting member (5) has a riveting hole (501) that runs through the thickness direction. The riveting hole (501) includes a first hole segment (5011) and a second hole segment (5012) arranged in a direction away from the third mating segment (2011). The inner diameter of the second hole segment (5012) is larger than the inner diameter of the first hole segment (5011). The outer diameters of the third mating segment (2011) and the fifth mating segment (2013) are both larger than the inner diameter of the first hole segment (5011). The fourth mating segment (2012) is inserted into the first hole segment (5011), and the fifth mating segment (2013) is inserted into the second hole segment (5012). The fifth mating segment (2013) is riveted to the riveting member (5).

9. The top cover assembly according to any one of claims 1 to 4, characterized in that, The end face of the second column segment (202) away from the first column segment (201) is flush with the end face of the connecting piece (3) away from the cover plate (1).

10. A battery cell, characterized in that, include: The housing has an internal cavity and an opening on one side communicating with the cavity; A battery cell is disposed in the receiving cavity, and the battery cell includes tabs; The top cover assembly according to any one of claims 1 to 9 is disposed at the opening of the housing and connected to the housing, and the connecting piece (3) is electrically connected to the tab.

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