Cylindrical lithium battery

Abstract

The cylindrical lithium battery comprises a shell, a roll core, a cover plate assembly and a positive collector plate, the cover plate assembly comprises a cover plate, a positive pole and a negative pole which are insulated from one another, the cover plate is simultaneously provided with the positive pole and the negative pole, and the positive pole and the negative pole are insulated from one another, so that the shell of the cylindrical lithium battery is not electrified; according to the cylindrical lithium battery, the damage risk of the insulating film caused by the cylindrical lithium battery with an electrified shell is favorably solved, the internal space of the battery is increased, the energy density of the battery is improved, a thinner insulating film can be used for replacing or not using the insulating film, and the use cost of the insulating film is reduced; and the design of the positive pole, the positive collector plate and the anti-explosion valve solves the problem that the existing structure is not suitable for the scheme that the shell is not electrified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a cylindrical lithium battery. BACKGROUND

[0002] In the related art, the negative electrode of the large cylindrical battery is generally in contact with the steel shell, so that the steel shell body is charged. With the development of large cylindrical batteries towards high-rate charging and discharging, although the battery is protected by an insulating film, the film itself has a certain risk of damage, and a thick insulating film reduces the space inside the battery and reduces the energy density. Moreover, the design of the positive current collector, the positive pole and the explosion-proof valve cannot adapt to the new cylindrical lithium battery mechanism without charging the shell. CONTENT OF THE UTILITY MODEL

[0003] The present application provides a cylindrical lithium battery to at least solve the technical problems of high cost, risk of damage and low energy density of the insulating film caused by the charging of the shell in the existing cylindrical lithium battery.

[0004] The present application provides a cylindrical lithium battery, comprising: a shell, a cover plate assembly and a roll core, the cover plate assembly is connected to one end of the shell and seals the roll core, the cover plate assembly comprises a positive pole, a negative pole and a cover plate which are connected to each other in an insulating manner, the roll core is provided with a center axis hole penetrating through and comprises a first upper surface and a first lower surface in the thickness direction of the cover plate, the first upper surface is provided with a first notch, the first lower surface is provided with a second notch, and the first notch and the second notch correspond to each other in the thickness direction of the cover plate.

[0005] The positive pole is provided with a first hole in the axial direction thereof, and the negative pole is arranged in the first hole. The positive pole has opposite first and second end portions, and the first hole is arranged at the first end portion. The positive pole comprises a second upper surface and a second lower surface, the second upper surface is arranged at the first end portion, and the second lower surface is arranged at the second end portion. The first end portion is used as a positive terminal of the cylindrical lithium battery, the second lower surface is provided with a counterbore, the first hole is arranged in the middle of the counterbore and communicates with the counterbore, and the diameter of the counterbore is greater than the diameter of the first hole.

[0006] A positive electrode current collecting disk, wherein the positive electrode current collecting disk is arranged between the cover plate assembly and the winding core to connect the positive electrode column to the winding core. The positive electrode current collecting disk includes a first disk body and a first connecting member. The first connecting member is connected to the first disk body. The axial direction of the first connecting member is perpendicular to the radial direction of the first disk body. The first disk body includes a third upper surface facing the first connecting member and a third lower surface away from the first connecting member. The second lower surface is connected to the third upper surface. The outer wall of the first connecting member is connected to the inner wall of the second end portion forming the countersunk hole.

[0007] The cylindrical lithium battery according to the embodiment of the present application has at least the following beneficial effects:

[0008] The cylindrical lithium battery of the embodiment of the present application is compared to the prior art in which the negative electrode current collecting disk is connected to the cylindrical lithium battery shell and then the shell is used as the negative terminal. The negative terminal of the cylindrical lithium battery of this embodiment is not connected to the shell, so the cylindrical lithium battery shell of the present application is not charged. In this way, the risk of insulation film damage caused by the cylindrical lithium battery with a charged shell can be solved, the space inside the battery is increased, the energy density of the battery is improved, a thinner insulation film can be used as a substitute or no insulation film is used, and the cost of using the insulation film is reduced. In the related art, the relationship between the positive and negative poles does not need to be considered on the cover plate, so that after the cylindrical lithium battery is changed to the shell without charging scheme in this embodiment, the positive pole, the positive current collecting disk and the explosion-proof valve cannot adapt to the cylindrical lithium battery structure with an uncharged shell. In this embodiment, a hole for installing the negative pole is opened on the positive pole, and a hole for the negative pole collecting disk to pass through is also opened in the positive current collecting disk. When the negative pole collecting disk is not connected to the shell, a channel for connecting the negative pole to the negative pole is provided. Moreover, the connection method between the positive electrode column and the positive current collecting plate is quite different from that of the related art. This application adopts two connection methods in different directions and positions, namely horizontal and vertical directions. The related art only adopts the connection method in the same position in the horizontal direction. This application has better connection strength and adapts to the connection strength requirements of the non-charged shell solution.

[0009] In one possible embodiment, the length of the positive electrode column in the non-first hole area of ​​the first end along the radial direction of the positive electrode column is L1, the cover plate is circular, the radius of the cover plate is L2, 24%≤L1 / L2≤30%; the length of the second end in the non-counterbore area along the radial direction of the positive electrode column is L3, 10%≤L3 / L2≤15%, which ensures both the riveting effect of the cover plate assembly as a whole and the strength of the positive electrode column after riveting.

[0010] In one possible embodiment, the diameter of the countersunk hole is L4, the diameter of the first hole is L5, 25%≤L5 / L4≤30%, and the range of L5 / L4 is designed to be 25%-30%, which helps to balance the welding strength and the structural strength of the positive electrode column.

[0011] In one possible embodiment, the cover plate assembly further includes a lower plastic member connected to the first lower surface of the cover plate. The side surface of the second end of the positive electrode column is configured with a flush portion and a protrusion. The flush portion is located between the protrusion and the first lower surface of the cover plate. The flush portion, the protrusion, and the first lower surface collectively define a first groove, which is used to accommodate at least a portion of the lower plastic member. By partially positioning the lower plastic member in the first groove and connecting one surface of the lower plastic member to the first lower surface, the lower plastic member is more securely fixed in the embodiment of the present application, compared to related art methods in which the lower plastic member is secured solely by connection to the first lower surface.

[0012] In one possible embodiment, the first disk body is circular and includes a second hole disposed at its center. The cylindrical lithium battery further includes a negative electrode current collector disk. The first connector is a hollow cylinder. The first connector body is provided with a third hole extending through the thickness of the first disk body. The second hole is located in the middle of and communicates with the third hole. At least a portion of the negative electrode current collector disk is sequentially passed through the central axis hole, the second hole, and the third hole. The diameter of the second hole is L6, the diameter of the first disk body is L7, and the thickness of the first disk body is L8. 8% ≤ L6 / L7 ≤ 15%, and 3% ≤ L8 / L6 ≤ 6%. A L6 / L7 ratio in the range of 8%-15% and a L8 / L6 ratio in the range of 3%-6% are beneficial for balancing the wettability and strength of the first disk body.

[0013] In a possible embodiment, the first disk body further includes a plurality of fourth holes arranged around the second hole, and the plurality of fourth holes are arranged outside the projection of the first connecting member along the thickness direction of the first disk body; the diameter of the fourth hole is L9, the diameter of the first disk body is L7, 10%≤L9 / L7≤30%, and the ratio range of L9 / L7 is 10%-30%, which is conducive to balancing the infiltration effect and the strength of the first disk body.

[0014] In a possible embodiment, the first notch and the second notch are circular in shape, and the projection of the positive electrode column along the thickness direction of the cover plate is located within the first notch, so that the layout of the positive electrode column and the notches on the cover plate is more reasonable, thereby ensuring the strength of the cover plate.

[0015] In one possible embodiment, the depth of the first notch is D1, the depth of the second notch is D2, the thickness of the cover plate is D3, and (D1+D2) / D3 is 40%-60%, which helps to ensure the fracture stability of the first notch and the second notch, that is, the valve opening stability, while meeting the strength of the cover plate.

[0016] In one possible embodiment, the cover plate is circular, and the centers of the cover plate, the first notch, and the second notch are at the same point. The first notch and the second notch are both at a distance D4 from the edge of the cover plate, and 3mm≤D4≤4mm. This is beneficial for balancing the impact of the laser sealing operation on the notch and avoiding interference of the lower plastic part with the notch.

[0017] In one possible embodiment, the cover plate assembly further includes a first upper plastic part and a second upper plastic part, the first upper plastic part being arranged between the positive electrode column and the cover plate to insulate the two, and the second upper plastic part being arranged between the positive electrode column and the negative electrode column to insulate the two, the first disk body 41 being circular in shape, and the first disk body including a second hole arranged at the center of the circle, the positive current collecting disc further including a first insulating part, and the first insulating part being arranged on the inner side wall forming the second hole to insulate the positive current collecting disc and the negative current collecting disc from each other to ensure the stability inside the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 is a cross-sectional schematic diagram of a cylindrical lithium battery provided in an embodiment of the present application;

[0020] Figure 2 1 is a cross-sectional schematic diagram of a cover plate assembly and a positive electrode current collecting plate of a cylindrical lithium battery provided in an embodiment of the present application;

[0021] Figure 3 1 is a cross-sectional schematic diagram of a cover plate of a cylindrical lithium battery provided in an embodiment of the present application;

[0022] Figure 4 1 is a cross-sectional schematic diagram of a positive electrode column of a cylindrical lithium battery provided in an embodiment of the present application;

[0023] Figure 5 yes Figure 4 A partial schematic diagram of the middle part;

[0024] Figure 6 1 is a top view of a positive electrode current collecting disk of a cylindrical lithium battery provided in an embodiment of the present application;

[0025] Figure 7 1 is a cross-sectional schematic diagram of a positive electrode current collecting disk of a cylindrical lithium battery provided in an embodiment of the present application;

[0026] Figure 8 yes Figure 7 Partial schematic diagram at point C in the middle;

[0027] Figure 9 yes Figure 3 Partial schematic diagram of point B in the middle.

[0028] Reference numerals:

[0029] 1- housing;

[0030] 2-cover plate assembly, 21-positive electrode column, 211-first hole, 212-first end, 2121-second upper surface, 213-second end, 2131-second lower surface, 2132-counter hole, 2133-flush portion, 2134-protrusion, 22-negative electrode column, 23-cover plate, 231-first upper surface, 232-first lower surface, 233-first notch, 234-second notch, 24-lower plastic part, 25-first upper plastic part, 26-second upper plastic part;

[0031] 3-winding core, 31-center axis hole;

[0032] 4-positive electrode current collecting disc, 41-first disc body, 411-third upper surface, 412-third lower surface, 413-second hole, 414-fourth hole, 42-first connecting member, 421-third hole, 43-first insulating member;

[0033] 5-Negative electrode current collecting plate. DETAILED DESCRIPTION

[0034] Examples of the present embodiment are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present embodiment and are not to be construed as limiting the present embodiment.

[0035] In the description of this embodiment, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this embodiment.

[0036] In the description of this embodiment, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0037] In the description of this embodiment, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this embodiment based on the specific content of the technical solution.

[0038] The cylindrical lithium batteries provided in the embodiments of this application include various size series, such as the 21 series (cylindrical lithium batteries with an outer diameter of 21mm) and the 46 series (cylindrical lithium batteries with an outer diameter of 46mm), which are not limited here. In the embodiments of this application, the 4680 (cylindrical lithium batteries with an outer diameter of 46mm and a height of 80mm) battery is used as an example for illustration. Specifically, Figures 1-9As shown, the shell 1, the cover assembly 2 and the winding core 3, the cover assembly 2 is connected to one end of the shell 1 and closes the winding core 3, the cover assembly 2 includes a positive electrode column 21, a negative electrode column 22 and a cover 23 that are insulated from each other, and the winding core 3 is provided with a central axis hole 31 passing through; the cover 23 includes a first upper surface 231 and a first lower surface 232 along the thickness direction of the cover 23, the first upper surface 231 is provided with a first notch 233, the first lower surface 232 is provided with a second notch 234, the first notch 233 and the second notch 234 correspond to each other along the thickness direction of the cover 23; the positive electrode column 21 is provided with a first hole 211 along its axial direction, the negative electrode column 22 is provided in the first hole 211, the positive electrode column 21 has opposite first end portions 212 and second end portions 213, the first hole 211 is provided at the first end portion 212, the positive electrode column 21 includes a second upper surface 2121 and a second lower surface 2131, the second upper surface 2121 is provided at the first end portion 212, the second lower surface 2131 The lower surface 2131 is provided at the second end portion 213, the first end portion 212 is used as the positive terminal of the cylindrical lithium battery, the second lower surface 2131 is provided with a countersunk hole 2132, the first hole 211 is provided in the middle of the countersunk hole 2132 and is connected to the countersunk hole 2132, the diameter of the countersunk hole 2132 is larger than the diameter of the first hole 211; the positive current collecting disk 4 is provided between the cover assembly 2 and the winding core 3, and the positive column 21 is connected to the winding core 3. The positive current collecting disk 4 includes The first disk body 41 and the first connecting member 42 are connected to the first disk body 41. The axial direction of the first connecting member 42 is perpendicular to the radial direction of the first disk body 41. The first disk body 41 includes a third upper surface 411 facing the first connecting member 42 and a third lower surface 412 facing away from the first connecting member 42. The second lower surface 2131 is connected to the third upper surface 411. The outer wall of the first connecting member 42 is connected to the inner wall of the second end 213 forming the countersunk hole 2132. Compared with the negative electrode current collecting disk 5 in the prior art, which is connected to the cylindrical lithium battery shell 1 and then uses the shell 1 as the negative terminal, the negative terminal of the cylindrical lithium battery in this embodiment is not connected to the shell 1. Therefore, the cylindrical lithium battery shell 1 of the present application is not charged. In this way, the risk of insulation film damage caused by the cylindrical lithium battery with a charged shell 1 can be solved, the space inside the battery can be increased, the energy density of the battery can be improved, a thinner insulation film can be used as a substitute or no insulation film can be used, and the cost of using the insulation film can be reduced.Moreover, in the related art, the relationship between the positive electrode column and the negative electrode column does not need to be considered on the cover plate, so that after the cylindrical lithium battery is changed to the non-charged shell scheme in this embodiment, the connection strength of the positive electrode column and the positive current collector disk cannot adapt to the high requirements of the non-charged shell for connection strength. The connection method between the positive electrode column and the positive current collector disk in the embodiment of the present application is quite different from that in the related art. The present application adopts two different directions in the horizontal direction and the vertical direction, and the first disk body and the first connecting member of the positive current collector disk are respectively connected to different positions of the positive electrode column. In the related art, the positive current collector disk does not adopt the design of the first connecting member, but only the first disk body, so the positive collector disk and the positive electrode column in the related art only adopt the connection method of the same position in the horizontal direction. Therefore, the present application has better connection strength and adapts to the high requirements of the non-charged shell scheme for connection strength.

[0039] In some embodiments, please refer to Figure 4 , the length of the positive electrode column 21 in the non-first hole 211 area of ​​the first end 212 along the radial direction of the positive electrode column 21 is L1, the cover plate 23 is circular, and the radius of the cover plate 23 is L2, 24%≤L1 / L2≤30%, which not only ensures the riveting effect of the cover plate assembly 2 as a whole, but also ensures the strength of the positive electrode column 21 after riveting. Furthermore, the preferred values ​​of L1 / L2 are 26%, 27%, and 28%, which are not further limited. The positive electrode column 21 and the cover plate 23 are assembled by a riveting process. Before riveting, the positive electrode column 21 has a first end 212, and then the positive electrode column 21 is inserted into the cover plate 23. After the riveting process, the second end 213 is formed. At this time, the positive electrode column 21 and the cover plate 23 are assembled. In some embodiments, the cover plate assembly 2 also includes a first upper plastic part 25 arranged between the positive electrode column 21 and the cover plate 23. During the assembly process, the first upper plastic part 25 must first be placed between the positive electrode column 21 and the cover plate 23 to insulate the two after the positive electrode column 21 and the cover plate 23 are assembled.

[0040] In some embodiments, the length of the second end portion 213 in the non-counter hole 2132 area along the radial direction of the positive electrode column 21 is L3, 10%≤L3 / L2≤15%, which not only ensures the riveting effect of the entire cover plate assembly 2, but also ensures the strength of the positive electrode column 21 after riveting.

[0041] In some embodiments, the diameter of the countersunk hole 2132 is L4, and the diameter of the first hole 211 is L5, 25% ≤ L5 / L4 ≤ 30%. If the countersunk hole 2132 is too large, it will affect the structural strength of the positive electrode column. If the countersunk hole 2132 is too small, it will affect the welding of the positive electrode collector 4 and the cover plate 23, and will affect the overall riveting strength. In this embodiment, the range of L5 / L4 is designed to be 25%-30%, which helps to balance the welding strength and the structural strength of the positive electrode column.

[0042] In some embodiments, please refer to Figure 2 and Figure 5 The cover assembly 2 further includes a lower plastic part 24, which is connected to the first lower surface 232 of the cover 23. The side surface of the second end 213 of the positive electrode column 21 is configured with a flush portion 2133 and a protruding portion 2134. The flush portion 2133 is located between the protruding portion 2134 and the first lower surface 232 of the cover 23, and the flush portion 2133, the protruding portion 2134 and the first lower surface 232 jointly define a first groove 214. Figure 5 The first groove 214 shown in the figure also includes the lower plastic part 24, so the two overlap in the figure. Figure 5 The first groove 214 indicated by the reference numeral 214 is the groove present when the lower plastic member 24 is not assembled. The first groove 214 is used to accommodate at least a portion of the lower plastic member 24. By partially positioning the lower plastic member 24 in the first groove 214 and connecting one surface of the lower plastic member 24 to the first lower surface 232, the lower plastic member 24 in the embodiment of the present application is more securely fixed, compared to the related art where the lower plastic member 24 is secured solely by connection to the first lower surface 232.

[0043] In some embodiments, please refer to Figure 6 、 Figure 7 and Figure 8 The first plate 41 is circular and includes a second hole 413 at its center. The cylindrical lithium battery also includes a negative electrode current collector 5. The first connector 42 is a hollow cylinder. A third hole 421 is provided through the first connector 42 along the thickness of the first plate 41. The second hole 413 is located in the middle of and communicates with the third hole 421. At least a portion of the negative electrode current collector 5 is sequentially passed through the central axis hole 31, the second hole 413, and the third hole 421. The diameter of the second hole 413 is L6, the diameter of the first plate 41 is L7, and the thickness of the first plate 41 is L8. 8% ≤ L6 / L7 ≤ 15%, and 3% ≤ L8 / L6 ≤ 6%. A L6 / L7 ratio of 8%-15% and a L8 / L6 ratio of 3%-6% are beneficial for balancing the wettability and strength of the first plate 41.

[0044] In some embodiments, the first disk body 41 also includes a plurality of fourth holes 414 arranged around the second hole 413, and the plurality of fourth holes 414 are arranged outside the projection of the first connecting member 42 along the thickness direction of the first disk body 41; the diameter of the fourth hole 414 is L9, the diameter of the first disk body 41 is L7, 10%≤L9 / L7≤30%, and the ratio range of L9 / L7 is 10%-30%, which is conducive to balancing the wetting effect and the strength of the first disk body 41.

[0045] In some embodiments, please refer to Figure 2 、 Figure 3 and Figure 9The first notch 233 and the second notch 234 are circular in shape, and the projection of the positive electrode column 21 along the thickness direction of the cover plate 23 is located within the first notch 233, making the layout of the positive electrode column and the notches on the cover plate more reasonable and ensuring the strength of the cover plate.

[0046] In some embodiments, the depth of the first notch 233 is D1, the depth of the second notch 234 is D2, the thickness of the cover plate 23 is D3, and (D1+D2) / D3 is 40%-60%. The first notch 233 and the second notch 234 are explosion-proof valves, which are used to break and release pressure when the internal pressure of the cylindrical lithium battery is too high, thereby preventing the cylindrical lithium battery from exploding. In this embodiment, since the first notch 233 and the second notch 234 are respectively located on the upper and lower surfaces of the cover plate 23, and the positions of the two notches correspond, the depth of the two notches determines the thickness of the cover plate 23 at the notch positions. If the notch is too deep, the residual thickness of the cover plate 23 is small, reducing the strength of the cover plate 23. If the notch is too shallow, the pressure required for the first notch 233 and the second notch 234 to break is unstable, that is, the opening of the explosion-proof valve is unstable. In this embodiment, the range of (D1+D2) / D3 is designed to be 40%-60%, which helps to ensure the fracture stability of the first notch 233 and the second notch 234, that is, the valve opening stability, on the basis of meeting the strength of the cover plate 23.

[0047] In some embodiments, the cover plate 23 is circular, with the cover plate 23, first notch 233, and second notch 234 centered at the same point. The first notch 233 and second notch 234 are each located a distance D4 from the edge of the cover plate 23, with a value of 3mm≤D4≤4mm. If the notch is too close to the edge of the cover plate 23, thermal effects during laser sealing may affect the explosion-proof valve, causing deformation and compromising its stability. If the notch is too far from the edge of the cover plate 23, the lower plastic component 24 may interfere with the notch on the inner explosion-proof valve. Keeping the length of D4 between 3mm and 4mm helps balance the impact of the laser sealing operation on the notch and prevent interference from the lower plastic component 24.

[0048] In some embodiments, the cover plate assembly 2 further includes a first upper plastic member 25 and a second upper plastic member 26. The first upper plastic member 25 is disposed between the positive electrode column 21 and the cover plate 23 to insulate the two, while the second upper plastic member 26 is disposed between the positive electrode column 21 and the negative electrode column 22 to insulate the two. The first disk 41 is circular and includes a second hole 413 disposed at its center. The positive current collector 4 further includes a first insulating member 43 disposed on the inner sidewall of the second hole 413 to insulate the positive current collector 4 from the negative current collector 5, thereby ensuring internal stability of the battery. In some embodiments, the first upper plastic member 25 and the second upper plastic member 26 are made of an insulating material, such as plastic or rubber, without specific limitation.

[0049] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present embodiment. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be appropriately combined in any one or more embodiments or examples.

[0050] Although the embodiments of the present embodiment have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made thereto without departing from the principles and spirit of the present embodiment, and the scope of the present embodiment is defined by the claims and their equivalents.

Claims

1. A cylindrical lithium battery, characterized in that: include: A housing (1), a cover plate assembly (2) and a winding core (3), wherein the cover plate assembly (2) is connected to one end of the housing (1) and closes the winding core (3), the cover plate assembly (2) comprises a positive pole (21), a negative pole (22) and a cover plate (23) which are insulated and connected to each other, and the winding core (3) is provided with a central axis hole (31) therethrough; The cover plate (23) comprises a first upper surface (231) and a first lower surface (232) along the thickness direction of the cover plate (23); the first upper surface (231) is provided with a first notch (233); the first lower surface (232) is provided with a second notch (234); the first notch (233) and the second notch (234) correspond to each other along the thickness direction of the cover plate (23); The positive electrode column (21) is provided with a first hole (211) along its axial direction, the negative electrode column (22) is provided in the first hole (211), the positive electrode column (21) has a first end (212) and a second end (213) opposite to each other, the first hole (211) is provided at the first end (212), the positive electrode column (21) comprises a second upper surface (2121) and a second lower surface (2131), the second upper surface (2121) is provided at the first end (212), the second lower surface (2131) is provided at the second end (213), the first end (212) is used as the positive terminal of the cylindrical lithium battery, the second lower surface (2131) is provided with a countersunk hole (2132), the first hole (211) is provided in the middle of the countersunk hole (2132) and is connected to the countersunk hole (2132), the diameter of the countersunk hole (2132) is larger than the diameter of the first hole (211); A positive electrode current collecting disc (4), the positive electrode current collecting disc (4) being arranged between the cover plate assembly (2) and the winding core (3) to connect the positive electrode column (21) to the winding core (3), the positive electrode current collecting disc (4) comprising a first disc body (41) and a first connecting member (42), the first connecting member (42) being connected to the first disc body (41), the axial direction of the first connecting member (42) being perpendicular to the radial direction of the first disc body (41), the first disc body (41) comprising a third upper surface (411) facing the first connecting member (42) and a third lower surface (412) facing away from the first connecting member (42), the second lower surface (2131) being connected to the third upper surface (411), and the outer side wall of the first connecting member (42) being connected to the inner wall of the second end portion (213) forming the counterbore (2132).

2. The cylindrical lithium battery according to claim 1, wherein: The length of the positive electrode column (21) in the area of ​​the first end (212) other than the first hole (211) along the radial direction of the positive electrode column (21) is L1, the cover plate (23) is circular, the radius of the cover plate (23) is L2, and 24%≤L1 / L2≤30%; the length of the second end (213) in the area other than the countersunk hole (2132) along the radial direction of the positive electrode column (21) is L3, and 10%≤L3 / L2≤15%.

3. The cylindrical lithium battery according to claim 2, wherein: The diameter of the countersunk hole (2132) is L4, the diameter of the first hole (211) is L5, and 25%≤L5 / L4≤30%.

4. The cylindrical lithium battery according to claim 2, wherein: The cover plate assembly (2) further includes a lower plastic part (24), the lower plastic part (24) being connected to the first lower surface (232) of the cover plate (23), the side surface of the second end portion (213) of the positive electrode column (21) being configured with a flush portion (2133) and a protruding portion (2134), the flush portion (2133) being located between the protruding portion (2134) and the first lower surface (232) of the cover plate (23), and the flush portion (2133), the protruding portion (2134) and the first lower surface (232) jointly defining a first groove (214), the first groove (214) being used to accommodate at least a portion of the lower plastic part (24).

5. The cylindrical lithium battery according to any one of claims 1 to 4, characterized in that: The first disk (41) is circular in shape, and includes a second hole (413) arranged at the center of the circle. The cylindrical lithium battery also includes a negative electrode collector disk (5). The first connecting member (42) is a hollow cylinder. The first connecting member (42) is provided with a third hole (421) along the thickness direction of the first disk (41). The second hole (413) is located in the middle of the third hole (421) and is connected. At least part of the negative electrode collector disk (5) is sequentially passed through the central axis hole (31), the second hole (413) and the third hole (421). The diameter of the second hole (413) is L6, the diameter of the first disk (41) is L7, the thickness of the first disk (41) is L8, 8%≤L6 / L7≤15%, and 3%≤L8 / L6≤6%.

6. The cylindrical lithium battery according to claim 5, wherein: The first disk body (41) further includes a plurality of fourth holes (414) arranged around the second hole (413), and the plurality of fourth holes (414) are arranged outside the projection of the first connecting member (42) along the thickness direction of the first disk body (41); the diameter of the fourth holes (414) is L9, the diameter of the first disk body (41) is L7, and 10%≤L9 / L7≤30%.

7. The cylindrical lithium battery according to claim 1, wherein: The first notch (233) and the second notch (234) are in the shape of a circular ring, and the projection of the positive electrode column (21) along the thickness direction of the cover plate (23) is located within the first notch (233).

8. The cylindrical lithium battery according to claim 7, wherein: The depth of the first notch (233) is D1, the depth of the second notch (234) is D2, the thickness of the cover plate (23) is D3, and (D1+D2) / D3 is 40%-60%.

9. The cylindrical lithium battery according to claim 8, wherein: The cover plate (23) is circular in shape, the cover plate (23), the first notch (233) and the second notch (234) have a common center point, and the first notch (233) and the second notch (234) are both at a distance D4 from the edge of the cover plate (23), 3mm≤D4≤4mm.

10. The cylindrical lithium battery according to claim 5, wherein: The cover plate assembly (2) further comprises a first upper plastic part (25) and a second upper plastic part (26), wherein the first upper plastic part (25) is arranged between the positive pole (21) and the cover plate (23) to insulate the two, and the second upper plastic part (26) is arranged between the positive pole (21) and the negative pole (22) to insulate the two, the first disk body (41) is circular, and the first disk body (41) comprises a second hole (413) arranged at the center of the circle, and the positive current collecting disk (4) further comprises a first insulating part (43), and the first insulating part (43) is arranged on the inner side wall forming the second hole (413) to insulate the positive current collecting disk (4) and the negative current collecting disk (5) from each other.

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