Current collector plate welding structure and cylindrical lithium ion battery

Abstract

This utility model relates to the field of cylindrical lithium-ion battery technology, and proposes a current collector welding structure and a cylindrical lithium-ion battery, including multiple welding lines. Each welding line comprises multiple straight lines and multiple rounded corner lines. The ends of the straight lines and the ends of the rounded corner lines are integrally formed and continuously arranged. Multiple straight lines and multiple rounded corner lines are alternately arranged and combined to form a wave shape. The line width of each straight line and each rounded corner line is W0. The angles between a straight line and its two adjacent straight lines are A and B, respectively, where 0.2mm≤W0≤0.4mm, 10°≤A≤30°, and 10°≤B≤30°. This utility model, by setting the welding lines to a wave shape, can increase the length of the welding lines within a specified span. By limiting the width of the welding lines and the angle between two adjacent straight lines, the battery can balance the welding quality and current carrying capacity at the welding line positions, thereby effectively improving the overall performance of the battery.

Description

Technical Field

[0001] This utility model relates to the field of cylindrical lithium-ion battery technology, and in particular to a current collector welding structure and a cylindrical lithium-ion battery. Background Technology

[0002] With the continuous development of new energy technologies, batteries, as high-efficiency energy storage devices, are widely used in various portable electronic products, electric vehicles, and large-scale energy storage systems. Among them, cylindrical lithium-ion batteries have gradually become one of the mainstream products in the market due to their excellent performance and high energy density. Welding, as a reliable connection method, can provide strong mechanical strength and enable the two welded components to conduct electricity. In the assembly process of cylindrical lithium-ion batteries, laser welding or ultrasonic welding is used to fix the positive and negative current collectors to the positive and negative tabs of the core, respectively, to ensure the performance stability and safety of the battery.

[0003] For example, the utility model disclosed in announcement number CN220895786U discloses a positive current collector, a negative current collector, and a cylindrical battery with all tabs. The positive current collector has positive welding patterns, and the negative current collector has negative welding patterns. The positive welding patterns and negative welding patterns are fixed to the positive and negative tabs of the core, respectively, and the welding patterns can be curved.

[0004] However, if the width of the weld bead is too small, it will weaken the current carrying capacity at the weld location, increase the internal resistance of the battery, and cause the temperature rise at the weld location to increase, affecting the battery performance. If the width of the weld bead is too large, the distance between the weld lines will be too close during welding, causing heat concentration at the weld location, which can easily lead to problems such as explosion points, affecting the structural strength and current carrying capacity of the weld location. If the bending angle of the weld bead is too small, the distance between the weld lines will be too close during welding, causing heat concentration at the weld location, which can easily lead to problems such as explosion points, affecting the structural strength and current carrying capacity of the weld location. If the bending angle of the weld bead is too large, it will shorten the length of the weld line within the specified span, weakening the current carrying capacity at the weld location, causing the temperature rise at the weld location to increase, affecting the battery performance. Utility Model Content

[0005] In view of this, this utility model proposes a current collector welding structure and a cylindrical lithium-ion battery. By reasonably setting the width of the welding line and the angle between two adjacent straight lines, the welding quality and current carrying capacity of the welding line position can be taken into account, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is implemented as follows: On the one hand, this utility model provides a current collector welding structure, including multiple welding lines, which are used for welding and fixing the current collector to the electrode, and are the welding trajectory of the current collector and the electrode.

[0007] The welding line includes multiple straight lines and multiple rounded lines. The ends of the straight lines and the ends of the rounded lines are integrally formed and continuously arranged. The multiple straight lines and the multiple rounded lines are alternately arranged and combined into a wave shape.

[0008] The line width of the straight line and the rounded corner line is W0. The angles between one of the straight lines and the two adjacent straight lines are A and B, respectively, where 0.2mm≤W0≤0.4mm, 10°≤A≤30°, and 10°≤B≤30°.

[0009] Based on the above technical solutions, preferably, the span of the welding wire along its length is L. 10 Where 3.9mm≤L 10 ≤5.1mm.

[0010] More preferably, the span of the welding wire along its width direction is W. 10 Where 2.4mm≤W 10 ≤3.2mm.

[0011] Secondly, this utility model provides a cylindrical lithium-ion battery, including the aforementioned welded structure and a positive electrode current collector, wherein the positive electrode current collector includes a disk body and a tail body, wherein...

[0012] The welding wire is disposed on the disk body and is used for welding and fixing the disk body to the positive electrode tab;

[0013] One end of the tail body is integrally formed on the disc body.

[0014] Based on the above technical solutions, preferably, a central hole is formed in the middle of the disk body, and the minimum distance between the bonding wire and the central hole is L. 11 Where 0.7mm≤L 11 ≤1.3mm.

[0015] More preferably, the minimum distance between the bonding wire and the periphery of the disk body is L. 12 Where 0.8mm≤L 12 ≤1.4mm.

[0016] Based on the above technical solutions, preferably, the disk body has peripheral holes, and the minimum distance between the bonding wire and the peripheral holes is W. 11 Where 0.4mm≤W 11 ≤0.8mm.

[0017] Based on the above technical solution, preferably, a narrowing groove is provided at the connection between the disc body and the tail body, and the width of the tail body at the narrowing groove is W. 31Where 2.5mm≤W 31 ≤3.5mm.

[0018] More preferably, the minimum distance between the welding wire and the narrowing groove is L. 20 Where 0.7mm≤L 20 ≤1.3mm.

[0019] More preferably, the width of the tail body is W. 30 The radius of the disk body is R1, where 5.5mm ≤ W 30 ≤6.5mm, 8.8mm≤R1≤9.4mm.

[0020] The current collector welding structure and cylindrical lithium-ion battery of this utility model have the following advantages over the prior art:

[0021] (1) By setting the welding line to a wavy shape, the length of the welding line within a specified span can be increased. By limiting the width of the welding line and the angle between two adjacent straight lines, the battery can take into account both the welding quality and current carrying capacity of the welding line position, thereby effectively improving the overall performance of the battery.

[0022] (2) By limiting the position and specifications of the welding wire, the welding quality and current carrying capacity of the welding wire position can be further improved, thereby further improving the overall performance of the battery.

[0023] (3) By setting the positive current collector to include a plate body and a tail body, the battery can be easily assembled. By setting a narrowing groove at the connection between the plate body and the tail body, the melting capability of the positive current collector can be improved, thereby ensuring the operational safety of the battery. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a top view of the disk portion of a cylindrical lithium-ion battery according to this utility model.

[0026] Figure 2 This is a top view of a manifold welding structure according to the present invention.

[0027] Figure 3 This is a top view of the narrowed groove in a cylindrical lithium-ion battery according to the present invention.

[0028] Figure 4 This is a top view of a cylindrical lithium-ion battery according to the present invention.

[0029] Among them: 1. Positive current collector; 11. Disc body; 12. Tail body; 101. Welding wire; 1011. Straight line; 1012. Rounded corner line; 102. Center hole; 103. Outer hole; 104. Narrowing groove; 2. Positive electrode tab. Detailed Implementation

[0030] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] This utility model discloses a cylindrical lithium-ion battery comprising a current collector, tabs, and a current collector welding structure. The tabs possess good conductivity and have a good connection with the electrode material. The current collector is also made of a highly conductive metal material, such as copper or aluminum, and is welded and fixed to the tabs via the current collector welding structure to collect the current generated by the internal electrodes of the battery and effectively transmit this current to the external connection points of the battery. During the charging and discharging process of the battery, the current collector can evenly distribute the current, avoiding current concentration that could lead to localized overheating, thereby improving the safety and performance stability of the battery.

[0032] The current collector welding structure includes multiple welding lines 101. When welding the current collector and the tab, the welding head moves along the welding lines 101 as the welding trajectory.

[0033] like Figure 2 As shown, the welding line 101 includes multiple straight lines 1011 and multiple rounded lines 1012. The ends of the straight lines 1011 and the ends of the rounded lines 1012 are integrally formed and continuously arranged. The multiple straight lines 1011 and multiple rounded lines 1012 are arranged alternately, and the multiple straight lines 1011 and multiple rounded lines 1012 are combined to form a wave shape. Within the same span, the length of the wave-shaped welding line 101 is greater, which can effectively improve the welding quality and welding reliability of the current collector and the electrode, and improve the current carrying capacity between the current collector and the electrode, thereby ensuring the overall performance of the battery.

[0034] Preferably, multiple welding wires 101 are arranged in a circumferential array around the axis of the cylindrical battery, and the line widths of the straight lines 1011 and the rounded corner lines 1012 are the same, thereby improving the welding quality, welding reliability and welding stability of the current collector and the electrode tab.

[0035] like Figure 2 As shown, the line width of the straight line 1011 and the fillet line 1012 is W0, that is, the line width of the weld line 101 is W0. The angles between a straight line 1011 and its two adjacent straight lines 1011 are A and B, respectively. Figure 1 As shown, the span of the bonding wire 101 along its length is L. 10 The span of the bonding wire 101 along its width direction is W. 10 .

[0036] In some embodiments, 0.2mm ≤ W0 ≤ 0.4mm, that is, the linewidth of the bonding wire 101 is 0.2mm, 0.3mm, or 0.4mm, etc. If W0 < 0.2mm, the linewidth of the bonding wire 101 is too small, which will weaken the current carrying capacity at the welding position, increase the internal resistance of the battery, and cause the temperature rise at the welding position to increase, affecting the performance of the battery. If W0 > 0.4mm, the linewidth of the bonding wire 101 is too large. During welding, the distance between the bonding wires 101 is too close, which leads to heat concentration at the welding position and is prone to problems such as explosion points, affecting the structural strength and current carrying capacity of the welding position.

[0037] Furthermore, W0 = 0.3mm, meaning the line width of welding line 101 is 0.3mm, thus ensuring both welding quality and current carrying capacity at the welding position, thereby effectively improving the overall performance of the battery.

[0038] In some embodiments, 10°≤A≤30°, that is, the angle between two adjacent straight lines 1011 is 10°, 20°, or 30°, etc. If A<10°, the angle between two adjacent straight lines 1011 is too small, the bending angle of the welding wire 101 is too small, and the distance between the welding wires 101 is too close during welding, resulting in heat concentration at the welding position, which can easily lead to problems such as explosion points, affecting the structural strength and current carrying capacity of the welding position. If A>30°, the angle between two adjacent straight lines 1011 is too large, the bending angle of the welding wire 101 is too large, which will cause the length of the welding wire 101 within the specified span to be shortened, weakening the current carrying capacity of the welding position, causing the temperature rise at the welding position to increase, and affecting the performance of the battery.

[0039] Correspondingly, the angle range of B should be the same as that of A, i.e., 10°≤B≤30°, so that the battery can take into account both the welding quality and the current carrying capacity of the welding position, thereby effectively improving the overall performance of the battery.

[0040] Furthermore, it is preferable to set A=B=18°, thereby improving the welding quality, welding reliability, and welding stability of the collector plate and the electrode tab.

[0041] In some embodiments, 3.9mm≤L 10 ≤5.1mm, meaning the span of the welding wire 101 along its length is 3.9mm, 4.5mm, or 5.1mm, etc. If L10 If the span of the welding wire 101 is less than 3.9mm, the span along its length is too small. This will not only reduce the current-carrying area at the welding point and increase the internal resistance, leading to concentrated heat generation at the welding point and increased battery rate temperature rise, but also reduce the connection strength at the welding point; if L 10 If the span is greater than 5.1mm, the span of the welding line 101 along its length is too large, and the welding position is likely to deviate from the weldable area on the current collector. This will not only increase welding time and welding cost and reduce welding efficiency, but also cause the battery to be scrapped.

[0042] Furthermore, L 10 =4.5mm, that is, the span of the welding line 101 along its length is 4.5mm, which enables the battery to take into account both the current carrying capacity and connection strength at the welding position, and improves welding efficiency and welding quality.

[0043] In some embodiments, 2.4mm≤W 10 ≤3.2mm, meaning the span of the weld wire 101 along its width direction is 2.4mm, 2.8mm, or 3.2mm, etc. If W 10 If the span of the bonding wire 101 is less than 2.4mm, the effective length of the bonding wire 101 is shortened, resulting in insufficient current carrying capacity and increased temperature rise at the welding position, affecting battery performance. Simultaneously, a small span of the bonding wire 101 along its width direction can also lead to excessive concentration of the bonding wire 101, causing heat concentration at the welding position, which can easily lead to problems such as explosion points and affect the structural strength of the welding position; if W 10 If the span of the welding line 101 is greater than 3.2mm, the welding position is likely to deviate from the weldable area on the current collector, resulting in some welding lines 101 becoming ineffective and insufficient effective welding area. This will not only cause the temperature at the welding position to rise, affecting the battery performance, but also reduce the connection strength at the welding position.

[0044] Furthermore, W 10 =2.8mm, that is, the span of the welding line 101 along its width direction is 2.8mm, which enables the battery to take into account both the current carrying capacity and connection strength at the welding position, and improves welding efficiency and welding quality.

[0045] The current collector includes a positive current collector 1 and a negative current collector, and the electrode tabs include a positive electrode tab 2 and a negative electrode tab. The positive current collector 1 and the positive electrode tab 2 are welded and fixed together by welding wire 101, and the negative current collector and the negative electrode tab are welded and fixed together by welding wire 101.

[0046] like Figure 1 and Figure 4As shown, the positive current collector 1 includes a plate body 11 and a tail body 12. The welding wire 101 is provided on the plate body 11 for welding and fixing the plate body 11 to the positive electrode tab 2. One end of the tail body 12 is integrally formed on the plate body 11. The tail body 12 is welded and fixed to the battery cap assembly. When assembling the battery, the assembly efficiency of the battery can be improved by bending the tail body 12.

[0047] The disc body 11 has a central hole 102 in the middle, which corresponds to the central hole of the winding core. Electrolyte can be added into the winding core through the central hole 102. Of course, when the battery is running, the gas generated in the winding core can be discharged to the explosion-proof valve through the central hole 102.

[0048] The disc body 11 is also provided with peripheral holes 103. The peripheral holes 103 are located on the outer periphery of the disc body 11. Their inner diameter is relatively small. They are mainly used to allow the gas generated in the winding core to be discharged to the explosion-proof valve through the peripheral holes 103. It is preferable to provide multiple peripheral holes 103 and arrange the multiple peripheral holes 103 in a circumferential array around the central hole 102 to improve the gas exhaust stability of the battery.

[0049] like Figure 2 As shown, the minimum distance between the bonding wire 101 and the center hole 102 is L. 11 The minimum distance between the bonding wire 101 and the periphery of the disk body 11 is L. 12 The minimum distance between the bonding wire 101 and the peripheral hole 103 is W. 11 .

[0050] In some embodiments, 0.7mm≤L 11 ≤1.3mm, meaning the minimum distance between the welding wire 101 and the center hole 102 is 0.7mm, 1mm, or 1.3mm, etc. A certain amount of offset will occur during the welding process; if L... 11 If the distance is less than 0.7mm, the gap between the welding wire 101 and the center hole 102 is too small. During welding, this will not only increase the welding difficulty but also easily cause the laser head to deviate from the weldable position of the disk body 11, reducing the weld connection strength. 11 If the distance is greater than 1.3mm, the gap between the welding wire 101 and the center hole 102 is too large, causing the welding wire 101 to be too close to the edge of the disk body 11. This will not only increase the welding difficulty, but also make the laser head deviate from the weldable position of the disk body 11, reducing the welding connection strength.

[0051] In some embodiments, 0.8mm≤L 12 ≤1.4mm, meaning the minimum distance between the solder wire 101 and the periphery of the disk 11 is 0.8mm, 1.1mm, or 1.4mm, etc. A certain amount of offset will occur during the soldering process. If L 12If the distance is less than 0.8mm, the gap between the welding wire 101 and the periphery of the disk 11 is too small. During welding, this will not only increase the welding difficulty but also easily cause the laser head to deviate from the weldable position of the disk 11, reducing the weld connection strength. 12 If the distance between the welding wire 101 and the periphery of the disk 11 is greater than 1.4mm, the distance between the welding wire 101 and the center hole 102 will be too small. The welding wire 101 will be too close to the center hole 102, which will not only increase the welding difficulty, but also make the laser head deviate from the weldable position of the disk 11, reducing the welding connection strength.

[0052] In some embodiments, 0.4mm≤W 11 ≤0.8mm, meaning the minimum distance between the welding wire 101 and the outer hole 103 is 0.4mm, 0.6mm, or 0.8mm, etc. A certain amount of offset will occur during the welding process. If W 11 If the distance is less than 0.4mm, the gap between the welding wire 101 and the outer hole 103 is too small. During welding, this will not only increase the welding difficulty but also make it easy for the laser head to weld into the outer hole 103, rendering part of the welding wire 101 ineffective, resulting in insufficient effective welding area, increased temperature rise at the welding position, affecting battery performance, and reducing the weld connection strength. 11 If the distance between the welding wire 101 and the outer hole 103 is greater than 0.8mm, the span of the welding wire 101 in the width direction will be reduced, the effective length of the welding wire 101 will be shortened, resulting in insufficient current carrying capacity, increased temperature rise at the welding position, and affecting the performance of the battery. At the same time, if the span of the welding wire 101 in the width direction is too small, the welding wire 101 will also be too concentrated, resulting in heat concentration at the welding position, which can easily lead to problems such as explosion points and affect the structural strength of the welding position.

[0053] Furthermore, L 11 =0.75mm, L 12 =1.1mm, W 11 =0.6mm, reducing the difficulty of battery welding, improving the welding connection strength at the welding position, and ensuring the current carrying capacity at the welding position.

[0054] like Figure 1 As shown, a narrowing groove 104 is provided at the connection between the disc body 11 and the tail body 12. The narrowing groove 104 can not only reduce the structural strength of the connection between the tail body 12 and the disc body 11, making it easier to bend, but also reduce the current flow area at the connection between the tail body 12 and the disc body 11, making the connection between the tail body 12 and the disc body 11 more prone to overheating and melting. In the event of battery thermal runaway, the battery can be disconnected in time to ensure the battery's operational safety.

[0055] like Figure 3 As shown, the tail body 12 is preferably a long strip-shaped plate structure with a width of W. 30The width of the tail section 12 at the narrowing groove 104 is W. 31 The minimum distance between the bonding wire 101 and the narrowing groove 104 is L. 20 ,like Figure 1 As shown, the radius of disk 11 is R1.

[0056] In some embodiments, 2.5mm≤W 31 ≤3.5mm, meaning the width of the tail section 12 at the narrowing groove 104 is 2.5mm, 3mm, or 3.5mm, etc. If W 31 If the width of the tail body 12 at the narrowing groove 104 is less than 2.5mm, the structural strength at the connection between the tail body 12 and the disc body 11 will be low, making it prone to deformation and breakage. The resulting metal foreign objects can easily cause a short circuit in the battery or increase the K value. Simultaneously, the insufficient width of the tail body 12 at the narrowing groove 104 will also weaken the current-carrying capacity at the connection between the tail body 12 and the disc body 11, failing to meet the battery's usage requirements. For example, during normal charging and discharging, the temperature rise at the connection between the tail body 12 and the disc body 11 will be high, easily leading to breakage and battery failure. If W... 31 If the width of the tail body 12 at the narrowing groove 104 is greater than 3.5mm, the melting capacity at the connection between the tail body 12 and the disc body 11 will be insufficient. When the battery experiences thermal runaway, it will be difficult to form an open circuit at the connection between the tail body 12 and the disc body 11, which will affect the safe operation of the battery.

[0057] Furthermore, W 31 =3mm, so that the connection between the tail body 12 and the disc body 11 takes into account both structural strength and melting capacity, ensuring the normal operation of the battery.

[0058] In some embodiments, 0.7mm≤L 20 ≤1.3mm, meaning the minimum distance between the welding line 101 and the narrowing groove 104 is 0.7mm, 1mm, or 1.3mm, etc. A certain amount of offset will occur during the welding process; if L... 20 If the distance is less than 0.7mm, the gap between the welding line 101 and the narrowing groove 104 is too small. During welding, this will not only increase the welding difficulty but also easily cause the laser head to deviate from the disk body 11, leading to battery failure and increasing battery processing costs. 20 If the gap is greater than 1.3mm, the distance between the welding line 101 and the narrowing groove 104 is too large. During welding, this will not only increase the welding difficulty, but also make it easy for the laser head to weld into the outer hole 103, resulting in some welding lines 101 becoming invalid, insufficient effective welding area, increased temperature rise at the welding position, affecting the performance of the battery, and reducing the welding connection strength.

[0059] Furthermore, L 20 =1mm, reducing the difficulty of battery welding, improving the welding connection strength at the welding position, and ensuring the current carrying capacity at the welding position.

[0060] In some embodiments, 5.5mm≤W 30 ≤6.5mm, 8.8mm≤R1≤9.4mm. If the overall width of the tail body 12 is larger, the solderable area of ​​the disc body 11 will be smaller. A reasonable tail body 12 width design helps to retain the largest solderable area of ​​the disc body 11. At the same time, it ensures that the tail body 12 not only has sufficient mechanical strength to prevent it from being broken during production, but also helps to improve the current carrying capacity of the positive electrode current collector 1, allowing electrons to pass through quickly and reducing the internal resistance of the battery.

[0061] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A manifold welding structure, characterized in that: It includes multiple welding lines (101), which are used for welding and fixing the collector plate and the electrode tab, and are the welding trajectory of the collector plate and the electrode tab; The welding line (101) includes multiple straight lines (1011) and multiple rounded lines (1012). The ends of the straight lines (1011) and the ends of the rounded lines (1012) are integrally formed and continuously arranged. The multiple straight lines (1011) and the multiple rounded lines (1012) are alternately arranged and combined into a wave shape. The line width of the straight line (1011) and the rounded corner line (1012) is W0. The angles between one of the straight lines (1011) and the two adjacent straight lines (1011) are A and B, respectively, where 0.2mm≤W0≤0.4mm, 10°≤A≤30°, and 10°≤B≤30°.

2. The manifold welding structure as described in claim 1, characterized in that: The span of the welding wire (101) along its length is L. 10 Where 3.9mm≤L 10 ≤5.1mm.

3. The manifold welding structure as described in claim 2, characterized in that: The span of the weld line (101) along its width direction is W. 10 Where 2.4mm≤W 10 ≤3.2mm.

4. A cylindrical lithium-ion battery, characterized in that: Including the welding structure and positive electrode current collector (1) as described in any one of claims 1-3, wherein the positive electrode current collector (1) comprises a disk body (11) and a tail body (12), wherein, The welding wire (101) is disposed on the disk body (11) for welding and fixing the disk body (11) to the positive electrode tab (2); One end of the tail body (12) is integrally formed on the disc body (11).

5. A cylindrical lithium-ion battery as described in claim 4, characterized in that: The disk body (11) has a central hole (102) in the middle, and the minimum distance between the bonding wire (101) and the central hole (102) is L. 11 Where 0.7mm≤L 11 ≤1.3mm.

6. A cylindrical lithium-ion battery as described in claim 5, characterized in that: The minimum distance between the bonding wire (101) and the periphery of the disk (11) is L. 12 Where 0.8mm≤L 12 ≤1.4mm.

7. A cylindrical lithium-ion battery as described in claim 4, characterized in that: The disk body (11) has an outer peripheral hole (103) inside, and the minimum distance between the bonding wire (101) and the outer peripheral hole (103) is W. 11 Where 0.4mm≤W 11 ≤0.8mm.

8. A cylindrical lithium-ion battery as described in claim 4, characterized in that: A narrowing groove (104) is provided at the connection between the disc body (11) and the tail body (12), and the width of the tail body (12) at the narrowing groove (104) is W. 31 Where 2.5mm≤W 31 ≤3.5mm.

9. A cylindrical lithium-ion battery as described in claim 8, characterized in that: The minimum distance between the welding line (101) and the narrowing groove (104) is L. 20 Where 0.7mm≤L 20 ≤1.3mm.

10. A cylindrical lithium-ion battery as described in claim 8, characterized in that: The width of the tail body (12) is W 30 The radius of the disk body (11) is R1, where 5.5mm ≤ W 30 ≤6.5mm, 8.8mm≤R1≤9.4mm.

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