Top cover assembly and single battery

Abstract

The utility model discloses a top cover assembly and a single battery. The top cover assembly comprises a cover plate, a first pole and a second pole, wherein the first pole and the second pole penetrate through the cover plate; specifically, a first through polar hole and a second through polar hole are formed in the cover plate; the first pole penetrates through the first pole hole, and upper plastic is arranged between the first pole and the first pole hole, so that the first pole is insulated from the cover plate; the second pole passes through the second pole hole, and the second pole is seamlessly and electrically connected with the cover plate. No gap exists between the second pole and the cover plate, so that the air tightness of the top cover assembly is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a top cover assembly and a single battery. Background Art

[0002] Electrolyte is a crucial medium for single-cell batteries to function. Therefore, the sealing of the battery casing significantly impacts the safety and lifespan of the battery. Due to insulation considerations, a common battery top cover assembly manufacturing method involves inserting the positive and negative electrode posts into the cover plate, with insulating members placed between the positive and negative posts, respectively. This results in poor airtightness between the positive and negative posts and the cover plate. Utility Model Content

[0003] One purpose of the present utility model is to provide a top cover assembly and a single battery, which aims to solve the technical problem that the air tightness between the pole and the cover plate of the top cover assembly is poor, which easily leads to leakage.

[0004] To achieve the above objectives, the present invention provides a solution: a top cover assembly comprising a cover plate and a first and second poles extending through the cover plate. Specifically, the cover plate is formed with a first pole hole and a second pole hole extending therethrough; the first pole extends through the first pole hole, and a plastic cover is disposed between the first pole and the first pole hole to insulate the first pole from the cover plate; the second pole extends through the second pole hole, and the second pole is seamlessly electrically connected to the cover plate.

[0005] In some embodiments, the second pole and the cover plate are an integral structure; or, the second pole and the cover plate are welded.

[0006] In some embodiments, the second pole includes an outer second pole and an inner second pole located on opposite sides of the cover plate, the inner second pole is used to connect to the battery cell, and the cross-sectional area of ​​the inner second pole is larger than the cross-sectional area of ​​the outer second pole.

[0007] In some embodiments, a height H between the top surface of the outer second pole and the cover plate is between 1 and 2 mm.

[0008] In some embodiments, the outer second pole and the inner second pole are cylinders, the diameter of the outer second pole is R1, 10 mm ≤ R1 ≤ 16 mm, and the diameter of the inner second pole is R2, 20 mm ≤ R2 ≤ 30 mm.

[0009] In some embodiments, the top cover assembly further includes a first pole sleeve, which is sleeved on the peripheral side wall of the first pole, and a wall thickness L1 of the first pole sleeve is between 0.5 mm and 1.5 mm.

[0010] In some embodiments, the top cover assembly further includes a second pole sleeve, which is sleeved on the peripheral side wall of the second pole, and a wall thickness L2 of the second pole sleeve is between 0.5 mm and 1.5 mm.

[0011] In some embodiments, the top cover assembly further includes an inner insulating layer, which covers the inner surface of the cover plate, and the first pole and the second pole are respectively passed through the inner insulating layer, and the thickness D1 of the inner insulating layer is between 0.5 mm and 1.5 mm.

[0012] In some embodiments, the top cover assembly further includes a pressure relief valve and an inner insulation layer, the cover plate is provided with a pressure relief hole, the pressure relief valve is connected to the cover plate to seal the pressure relief hole, the inner insulation layer includes an insulating sheet and a flange connected to each other, the insulating sheet covers the inner surface of the cover plate, the first pole and the second pole are respectively passed through the inner insulation layer, and the flange is arranged around the pressure relief hole and extends away from the cover plate.

[0013] In some embodiments, the thickness D2 of the insulating sheet is between 0.5 mm and 1.5 mm; and / or the wall thickness D3 of the flange is between 0.5 mm and 1.5 mm.

[0014] To achieve the above object, the present invention provides a solution: a single battery, which includes a shell and a battery cell arranged in the shell, and any of the top cover components described above, wherein the top cover component is connected to the shell and the battery cell respectively.

[0015] The beneficial effects of the present invention are:

[0016] The top cover assembly includes a cover plate and first and second poles extending through the cover plate. Specifically, the cover plate is formed with first and second pole holes extending therethrough. The first pole extends through the first pole hole, with plastic provided between the first pole and the first pole hole to insulate the first pole from the cover plate. The second pole extends through the second pole hole, and the second pole is seamlessly electrically connected to the cover plate. The first and second poles can be conventional cylindrical or rectangular poles, or any other pole shape as needed, with the first and second pole holes positioned accordingly.

[0017] Because the second pole and the cover plate are seamlessly electrically connected, compared to existing structures where mating surfaces exist between both the first pole and the cover plate, the top cover assembly of the present application only has a mating surface between the first pole and the cover plate. The second pole and the cover plate can be integrally formed, welded separately, or processed in any other manner. The advantage of this arrangement is that there is no airtight weak surface between the second pole and the cover plate due to assembly. The battery housing equipped with the top cover assembly of the present application has better sealing and is less prone to leakage accidents. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 1 This is an overall structural diagram of the top cover assembly provided by an embodiment of the present utility model;

[0020] Figure 2 This is an exploded schematic diagram of a top cover assembly provided by an embodiment of the present utility model;

[0021] Figure 3 It is a cross-sectional schematic diagram of a top cover assembly provided by an embodiment of the present utility model;

[0022] Figure 4 This is a schematic diagram of the dimensions of the first pole of the top cover assembly provided by an embodiment of the present utility model;

[0023] Figure 5 This is a schematic diagram of the dimensions of the second pole of the top cover assembly provided by an embodiment of the present utility model;

[0024] Figure 6 This is an exploded schematic diagram of another top cover assembly provided by an embodiment of the present utility model;

[0025] Figure 7 It is a cross-sectional schematic diagram of another top cover assembly provided by an embodiment of the present utility model;

[0026] Figure 8 This is a schematic diagram of the dimensions of the inner insulation layer of another top cover assembly provided in an embodiment of the present invention.

[0027] Description of Figure Numbers:

[0028] 1. Cover plate; 11. First pole hole; 12. Second pole hole; 13. Pressure relief hole; 2. First pole; 21. First pole body; 22. First end cap; 3. Second pole; 31. Outer second pole column; 32. Inner second pole column; 4. Upper plastic; 5. First pole sleeve; 6. Second pole sleeve; 7. Inner insulation layer; 71. Insulation sheet; 72. Flange; 8. Pressure relief valve. DETAILED DESCRIPTION

[0029] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0030] During battery operation, the pressure inside the shell will increase due to factors such as heating of the electrolyte or generation of gas. If the shell is not sealed well, there is a risk of electrolyte overflow and leakage, which greatly affects the safety and service life of the battery.

[0031] In order to solve the above technical problems, the present application provides a top cover assembly.

[0032] See also Figures 1 to 3 , Figure 1 This is an overall structural diagram of the top cover assembly provided by an embodiment of the present utility model; Figure 2 This is an exploded schematic diagram of a top cover assembly provided by an embodiment of the present utility model; Figure 3 It is a cross-sectional schematic diagram of the top cover assembly provided by an embodiment of the present utility model.

[0033] The top cover assembly includes a cover plate 1 and a first pole 2 and a second pole 3 extending through the cover plate 1. Specifically, the cover plate 1 is formed with a first pole hole 11 and a second pole hole 12 extending therethrough. The first pole 2 extends through the first pole hole 11, and an upper plastic 4 is disposed between the first pole 2 and the first pole hole 11 to insulate the first pole 2 from the cover plate 1. The second pole 3 extends through the second pole hole 12 and is seamlessly electrically connected to the cover plate 1.

[0034] In this embodiment, seamless electrical connection means that the second pole 3 and the cover plate 1 are integrally formed by casting, stamping, etc., or the second pole 3 and the cover plate 1 are formed separately but combined by forging, welding, etc. In the finished top cover assembly, there is no gap between the second pole 3 and the cover plate 1 that may cause the air tightness of the battery to be destroyed, and the second pole 3 and the cover plate 1 are conductive.

[0035] Compared with the prior art, in which there are mating surfaces between the first pole 2 and the cover plate 1 and between the second pole 3 and the cover plate 1, the present embodiment only has a mating surface between the first pole 2 and the cover plate 1, and the weak surfaces that destroy the airtightness are significantly reduced, thereby reducing the risk of battery leakage.

[0036] More importantly, in the actual use of the battery, the consumption rates of its positive and negative electrodes are not the same. An exemplary configuration scheme is: the first electrode 2 is configured as the positive electrode and the second electrode 3 is configured as the negative electrode. During the operation of the battery, the first electrode 2 undergoes a reduction reaction, so there is no consumption trend of the first electrode 2. Therefore, in this configuration scheme, there is no trend of a gap between the first electrode 2 and the cover plate 1 due to the consumption of the first electrode 2. Compared with the prior art, this embodiment does not simply reduce the original two airtight weak surfaces to one. The more important improvement is that only one of the two electrodes of this embodiment has the possibility of leakage. Therefore, the polarity of the two electrodes can be specifically configured to make the first electrode 2 less likely to leak than the second electrode 3, thereby significantly improving the reliability and service life of the battery.

[0037] The first pole 2 of this embodiment specifically comprises a first pole body 21 and a first end cap 22, which are threaded together. The end of the first pole body 21, away from the first end cap 22, is enlarged to form an end cap. The end cap and the first end cap 22 are respectively clamped from either side of the cover plate 1 to secure the relative position of the first pole 2 and the cover plate 1. The first pole 2 can also be configured in other common configurations such as riveting and clamping. The structure of this embodiment is only one technical solution. The cross-sections of the first pole 2 and the second pole 3 of this embodiment are schematically circular. The first pole 2 and the second pole 3 can also be configured as rectangular parallelepiped or other pole shapes as needed. The first pole hole 11 and the second pole hole 12 can be adjusted accordingly, as long as the above-mentioned matching relationship is achieved.

[0038] In this embodiment, the upper plastic 4 is sleeved around the circumferential surface of the first pole 2. The first pole 2 and the upper plastic 4 are inserted into the first pole hole 11 together. The upper plastic 4 separates the first pole 2 from the cover plate 1 to achieve insulation. In other embodiments, the upper plastic 4 can also be an insulating film plated on the circumferential surface of the first pole 2, or an insulating envelope wrapped around it, as long as it can ensure electrical insulation and airtightness between the first pole 2 and the cover plate 1.

[0039] In some embodiments, the second pole 3 and the cover plate 1 are an integral structure; or, the second pole 3 and the cover plate 1 are welded together.

[0040] In the above embodiment, the integral molding of the second pole 3 and the cover plate 1 is relatively simple, facilitating mass production. For an integral structure of the second pole 3 and the cover plate 1, they can be stamped or rapidly automated using a three-axis machining center. For welded second pole 3 and the cover plate 1, the structure of the second pole 3 and the cover plate 1 is a simple drawn part or thin sheet, resulting in high production efficiency. Different production methods correspond to different workpiece performance, and can be selected based on actual needs.

[0041] See also Figures 4 and 5 , Figure 4This is a schematic diagram of the dimensions of the first pole 2 of the top cover assembly provided in an embodiment of the present utility model; Figure 5 It is a schematic diagram of the dimensions of the second pole 3 of the top cover assembly provided in an embodiment of the present utility model.

[0042] In some embodiments, the second pole 3 includes an outer second pole 31 and an inner second pole 32 located on opposite sides of the cover plate 1 . The inner second pole 32 is used to connect to the battery cell, and the cross-sectional area of ​​the inner second pole 32 is larger than the cross-sectional area of ​​the outer second pole 31 .

[0043] For the top cover assembly in which the second electrode 3 and the cover plate 1 are designed as separate components, the contact surface between the second electrode 3 and the inner side of the cover plate 1 should not be too large to ensure airtightness between the second electrode 3 and the cover plate 1, and vice versa. This limits the cross-sectional area of ​​the second electrode 3. In this embodiment, the second electrode 3 and the cover plate 1 are integral, eliminating contact surface restrictions. Therefore, a larger cross-sectional area can be selected, increasing the contact area between the second electrode 3 and the electrolyte and improving battery power.

[0044] Specifically, the outer second pole 31 and the inner second pole 32 are cylinders. The diameter of the outer second pole 31 is R1, 10 mm ≤ R1 ≤ 16 mm, and the diameter of the inner second pole 32 is R2, 20 mm ≤ R2 ≤ 30 mm.

[0045] The contact area between the electrode and the electrolyte is positively correlated with battery power. A larger contact area can result in higher battery power, but this increase in contact area also increases the volume and weight of the electrode, which in turn reduces the electrode's current density. In this embodiment, 10mm ≤ R1 ≤ 16mm ensures that the outer second electrode 31 fits well with existing electrical equipment and meets load requirements. 20mm ≤ R2 ≤ 30mm maximizes the contact area between the second electrode 3 and the electrolyte without significantly affecting battery quality, resulting in higher battery power.

[0046] Furthermore, because the second pole 3 and the cover plate 1 are an integral structure, there is no need to consider the subsequent assembly problem between the second pole 3 and the cover plate 1, and the clamping and fixing of the second pole 3 can also be achieved indirectly by clamping the cover plate 1. Therefore, the outer second pole 31 can be set to a lower height to meet more compact assembly requirements. For example, the height H between the top surface of the outer second pole 31 and the cover plate 1 is between 1 and 2 mm.

[0047] In some embodiments, the top cover assembly further includes a first pole sleeve 5, which is sleeved around the circumferential sidewall of the first pole 2. The wall thickness L1 of the first pole sleeve 5 is between 0.5 mm and 1.5 mm. Specifically, the first pole sleeve 5 can cover the entire circumferential sidewall of the first pole 2, or only the circumferential surface of the first pole 2 exposed outside the cover plate 1.

[0048] The provision of the first pole sleeve 5 ensures that, after battery assembly, only the end surface of the first pole 2 is exposed for electrical connection to the device, reducing the risk of accidental leakage and short circuits. The wall thickness L1 of the first pole sleeve 5 ranges from 0.5mm to 1.5mm, achieving effective insulation without significantly affecting the assembly of the top cover assembly. The portion of the first pole 2 located inside the battery will be immersed in the electrolyte or in contact with other insulating materials and is therefore not considered.

[0049] In some embodiments, the top cover assembly further includes a second pole sleeve 6 , which is sleeved on the peripheral side wall of the second pole 3 , and a wall thickness L2 of the second pole sleeve 6 is between 0.5 mm and 1.5 mm.

[0050] Similar to the second pole sleeve 6, the second pole sleeve 6 can cover the entire circumferential sidewall of the second pole 3, or only the circumferential surface of the second pole 3 exposed outside the cover plate 1. The provision of the second pole sleeve 6 ensures that, after battery assembly, only the end face of the second pole 3 is exposed for electrical connection to the electrical device, reducing the risk of accidental leakage and short circuits. The wall thickness L2 of the second pole sleeve 6 ranges from 0.5 mm to 1.5 mm, achieving effective insulation without significantly affecting the assembly of the top cover assembly. The portion of the second pole 3 located inside the battery will be immersed in the electrolyte or in contact with other insulating materials and is therefore not considered.

[0051] In some embodiments, the top cover assembly further includes an inner insulating layer 7, which covers the inner surface of the cover plate 1. The first pole 2 and the second pole 3 are respectively penetrated by the inner insulating layer 7, and the thickness D1 of the inner insulating layer 7 is between 0.5 mm and 1.5 mm.

[0052] In existing solutions where both poles are insulated from the cover plate 1, the cover plate 1 has no downstream equipment and therefore does not participate in the battery reaction. However, in this embodiment, the cover plate 1 is seamlessly electrically connected to the second pole 3, allowing current to form a path through the first pole 2, the electrolyte, the cover plate 1, and the second pole 3. This poses a certain risk of loss and leakage in the cover plate 1. The provision of the inner insulating layer 7 ensures that the cover plate 1 does not participate in current transmission. The thickness D1 of the inner insulating layer 7 is between 0.5mm and 1.5mm, ensuring the insulation effect without excessively compressing the internal space of the battery housing.

[0053] It should be noted that the inner insulating layer 7 is only one of the improvements to the conductive nature of the cover plate 1 in this embodiment. In addition to the inner insulating layer 7, an outer insulating layer such as an envelope can also prevent leakage of the cover plate 1. Even without insulation treatment, leakage will only occur in certain usage scenarios, or the cover plate 1 will be depleted to the point where its physical and chemical properties fall below the expected specifications. In other cases, the bare cover plate 1 can still solve the technical problems of the present invention.

[0054] Furthermore, the top cover assembly also includes a pressure relief valve 8 and an inner insulation layer 7. Figures 6 to 8 , Figure 6 This is an exploded schematic diagram of another top cover assembly provided by an embodiment of the present utility model; Figure 7 It is a cross-sectional schematic diagram of another top cover assembly provided by an embodiment of the present utility model; Figure 8 It is a schematic diagram of the dimensions of the inner insulating layer 7 of another top cover assembly provided in an embodiment of the present utility model.

[0055] Specifically, the cover plate 1 is provided with a pressure relief hole 13, the pressure relief valve 8 is connected to the cover plate 1 to seal the pressure relief hole 13, the inner insulating layer 7 includes an insulating sheet 71 and a flange 72 connected to each other, the insulating sheet 71 covers the inner surface of the cover plate 1, the first pole 2 and the second pole 3 are respectively passed through the inner insulating layer 7, and the flange 72 is arranged around the pressure relief hole 13 and extends away from the cover plate 1.

[0056] Considering the expansion of the electrolyte within the battery due to the high operating temperature, and the inevitable generation of gas as the battery is used, resulting in high internal pressure, a pressure relief valve 8 is provided in the top cover assembly. When the internal pressure of the battery reaches a dangerous threshold, the pressure relief valve 8 opens to release pressure to the outside environment, reducing the risk of thermal runaway and explosion. The insulating sheet 71 and the cover plate 1 both mate with the pressure relief valve 8 via the sidewalls of the through-holes. This small mating surface presents certain airtightness defects. The provision of flange 72 increases the contact area between the inner insulating layer 7 and the pressure relief valve 8. When the flange 72 and the pressure relief valve 8 are airtight, even if there are gaps or cracks between the pressure relief valve 8 and the cover plate 1, this will not result in electrolyte leakage.

[0057] Furthermore, the thickness D2 of the insulating sheet 71 is between 0.5 mm and 1.5 mm; and / or the wall thickness D3 of the flange 72 is between 0.5 mm and 1.5 mm.

[0058] The insulating sheet 71 and the flange 72 are both arranged in the battery shell. The volume of the two will occupy the volume of the electrolyte. The thickness D2 of the insulating sheet 71 is between 0.5mm and 1.5mm, and the wall thickness D3 of the flange 72 is between 0.5mm and 1.5mm. This can reduce the impact on the electrolyte volume while ensuring the insulation effect as much as possible, thereby avoiding affecting the upper limit of the battery energy storage.

[0059] In order to solve the above problems, the present application also provides a single battery, which includes a shell and a battery cell arranged in the shell, and any of the top cover assemblies described above, wherein the top cover assembly is connected to the shell and the battery cell respectively.

[0060] The battery cells mentioned above may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc., and the embodiments of the present application do not limit this. The battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0061] A battery cell comprises an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode, a negative electrode, and a separator that insulates the two. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet comprises a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer. The current collectors uncoated with the positive active material layer, when stacked, serve as the positive electrode tabs. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet comprises a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer. The current collectors uncoated with the negative active material layer, when stacked, serve as the negative electrode tabs. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, for example. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0062] The battery cells disclosed in the embodiments of this application can be used in electrical devices, which may include but are not limited to mobile phones, tablets, laptops, electric toys, electric tools, electric vehicles, electric cars, ships, spacecraft, and the like. Electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to improve the stability of battery performance and battery life.

[0063] Because the battery cell of this embodiment includes the top cover assembly disclosed in the above embodiment, the battery cell of this embodiment has the same technical effect as the top cover assembly, and the battery cell of this embodiment has better sealing and safety than the existing battery cell.

[0064] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0065] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0066] The directional words appearing in the above description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made based on the design concept of the present invention and the contents of the present invention description and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A top cover assembly, characterized in that: include: a cover plate, wherein the cover plate is formed with a first pole hole and a second pole hole penetrating therethrough; a first pole, wherein the first pole hole is formed through the first pole; an upper plastic, disposed between the first pole and the first pole hole, so as to insulate the first pole from the cover plate; The second pole is provided with the second pole hole, and the second pole is seamlessly and electrically connected to the cover plate.

2. The top cover assembly according to claim 1, wherein: The second pole and the cover plate are an integral structure; or, the second pole and the cover plate are welded.

3. The top cover assembly according to claim 1, wherein: The second pole includes an outer second pole and an inner second pole located on opposite sides of the cover plate. The inner second pole is used to connect to the battery cell, and the cross-sectional area of ​​the inner second pole is larger than the cross-sectional area of ​​the outer second pole.

4. The top cover assembly according to claim 3, wherein: A height H between the top surface of the outer second pole and the cover plate is between 1 and 2 mm.

5. The top cover assembly according to claim 3, wherein: The outer second pole and the inner second pole are cylinders. The diameter of the outer second pole is R1, 10mm≤R1≤16mm, and the diameter of the inner second pole is R2, 20mm≤R2≤30mm.

6. The top cover assembly according to any one of claims 1 to 5, characterized in that: The top cover assembly further includes a first pole sleeve, which is sleeved on the peripheral side wall of the first pole. The wall thickness L1 of the first pole sleeve is between 0.5 mm and 1.5 mm.

7. The top cover assembly according to any one of claims 1 to 5, characterized in that: The top cover assembly further includes a second pole sleeve, which is sleeved on the peripheral side wall of the second pole, and a wall thickness L2 of the second pole sleeve is between 0.5 mm and 1.5 mm.

8. The top cover assembly according to any one of claims 1 to 5, characterized in that: The top cover assembly further includes an inner insulating layer, which covers the inner surface of the cover plate. The first pole and the second pole are respectively passed through the inner insulating layer. The thickness D1 of the inner insulating layer is between 0.5 mm and 1.5 mm.

9. The top cover assembly according to any one of claims 1 to 5, characterized in that: The top cover assembly also includes a pressure relief valve and an inner insulating layer. The cover plate is provided with a pressure relief hole. The pressure relief valve is connected to the cover plate to cover the pressure relief hole. The inner insulating layer includes an insulating sheet and a flange connected to each other. The insulating sheet covers the inner surface of the cover plate. The first pole and the second pole are respectively passed through the inner insulating layer. The flange is arranged around the pressure relief hole and extends away from the cover plate.

10. The top cover assembly according to claim 9, wherein: The thickness D2 of the insulating sheet is between 0.5 mm and 1.5 mm; and / or The wall thickness D3 of the flange is between 0.5 mm and 1.5 mm.

11. A single battery, characterized in that: include: A shell, a battery cell and a top cover assembly according to any one of claims 1 to 10, wherein the battery cell is arranged in the shell, and the top cover assembly is connected to the shell and the battery cell respectively.

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