Battery cell cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell cover plate and a battery cell. The battery cell cover plate comprises a pole assembled on a cover plate main body; the riveting piece is provided with a connecting hole, and the pole is riveted in the connecting hole and then is welded with the riveting piece; the connecting hole is of a stepped hole structure provided with a first stepped part, a second stepped part and a third stepped part which are sequentially arranged in the axial direction, and the hole diameters of the first stepped part, the second stepped part and the third stepped part are sequentially decreased. In the thickness direction of the cover plate main body, the height dimension h of the first step part is 0.2-0.5 mm; and the distance a between the inner wall of the first step part and the inner wall of the second step part is 0.5-1mm. Welding marks formed by a welding process can be prevented from protruding out of the upper surface of the riveting piece, so that the flatness of the riveting piece is guaranteed; the avoiding groove meeting the requirement of the welding process is formed in the riveting piece, and the influence of the welding process on the shape and size precision of the riveting piece is improved, so that the appearance yield of the battery cell cover plate is improved, and the safety and yield of the battery cell are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cover and a battery. Background Art

[0002] As lithium-ion battery technology matures, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing. The lithium battery cover is a key component in lithium-ion batteries. Its functions are to weld with the shell to form a sealed cavity, lead out the positive and negative electrodes of the electrode group, and serve as an assembly carrier.

[0003] In traditional cover plates, the pole is fixed by first riveting and then welding to the rivet block. After the pole and the rivet block are fixed by riveting, the overall structure of the cover plate has met the strength and sealing performance requirements. In theory, it does not need to be welded again. However, direct riveting will cause the internal resistance of the entire cover plate (from the surface of the rivet block facing the outside of the battery cell to the bottom surface of the pole facing the inside of the battery cell) to be too large. Therefore, a laser welding process is added to achieve a close fit between the pole and the riveted aluminum block to ensure the internal resistance and stability of the entire cover plate. However, laser welding is likely to affect the shape tolerance accuracy of the rivet block, thereby reducing the production yield of the cover plate. In addition, welding is also likely to cause the pole to melt, which reduces the strength of the pole and easily causes the cover plate to fail, thereby affecting the safety performance of the battery cell. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a battery cell cover and a battery cell to solve the problem that in the existing battery cell cover, the rivet block and the pole are first riveted and then welded, and the welding process easily affects the shape of the rivet block and the structural strength of the pole, thereby reducing the production yield of the battery cell cover and making the battery cell cover prone to failure.

[0005] A first aspect of the present invention provides a cell cover, wherein the cell cover comprises: The cover plate body is provided with a mounting hole; A pole, mounted in the mounting hole; A rivet is provided with a connection hole, the pole is riveted to the connection hole and then welded to the rivet; the connection hole is formed into a stepped hole structure having a first step portion, a second step portion and a third step portion which are sequentially arranged along the axial direction and whose hole diameters decrease sequentially; the pole is welded to the second step portion, and the first step portion is arranged at an end of the rivet facing away from the cover plate body; In the thickness direction of the cover plate body, the height dimension of the first step portion is h, h=0.2mm~0.5mm; in the radial direction of the connecting hole, the distance between the inner wall of the first step portion and the inner wall of the second step portion is a, a=0.5mm~1mm.

[0006] Preferably, a portion of the side wall of the pole which is arranged in the axial direction of the pole expands toward the second step portion to form a riveted boss, and the riveted boss is formed into an annular structure. Preferably, the distance between the portion of the side wall on the pole before riveting and the side wall on the riveting boss surrounding the axial direction of the pole after riveting is b, and b=0.3mm~0.6mm.

[0007] Preferably, in the thickness direction of the cover plate body, the height dimension of the riveted boss is H, H=0.8mm~1.5mm.

[0008] Preferably, in the thickness direction of the cover plate body, the height dimension of the riveted boss is H, in mm; in the thickness direction of the cover plate body, the height dimension of the rivet is H1, in mm, H= (33.3%~66.7%) H1.

[0009] Preferably, H1 ≥ 2.5 mm.

[0010] Preferably, after riveting, the pole is welded to the riveted piece to form a welding portion between the second step portion and the pole, and the penetration depth of the welding portion is B, in mm, and B / H=50%~80%.

[0011] Preferably, after welding, the flatness of the surface of the rivet facing away from the cover plate body is less than 0.2 mm.

[0012] Preferably, a side wall of one end of the pole facing the inside of the battery cell is formed with a connecting portion protruding outwardly in the radial direction of the pole; The battery cover plate also includes: A first insulating member, disposed between the cover plate body and the rivet member, wherein a portion of the first insulating member is covered on the rivet member and is disposed around the axial circumferential side wall of the pole; A second insulating member is disposed on a side of the cover body facing the inside of the battery cell, and a portion of the second insulating member is sandwiched between the connecting portion and the cover body; The sealing member is formed into an annular structure which is sleeved on the pole and surrounds the pole in the axial direction; part of the sealing member is sandwiched between the connecting portion and the cover plate body, and part of the sealing member extends between the mounting hole and the pole.

[0013] A second aspect of the present invention provides a battery cell, comprising the battery cell cover plate described in any of the above technical solutions.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The cell cover of the present invention has a connecting hole on the rivet, and the pole is riveted to the connecting hole and then welded to the rivet; the connecting hole is formed into a stepped hole structure having a first step portion, a second step portion and a third step portion which are sequentially arranged along the axial direction and whose apertures decrease sequentially, the pole and the second step portion are first riveted and then welded, and the first step portion is provided at an end of the rivet facing away from the cover body by limiting the height dimension h=0.2mm~0.5mm, thereby avoiding the weld mark formed by the welding process from protruding from the upper surface of the rivet, thereby ensuring the flatness of the rivet; in addition, the distance a=0.5mm~1mm between the inner wall of the first step portion and the inner wall of the second step portion is also limited, so that an avoidance groove that meets the requirements of the welding process is formed on the rivet, which improves the influence of the welding process on the shape accuracy and dimensional accuracy of the rivet to a certain extent, thereby improving the appearance yield of the cell cover, and then improving the safety and yield of the battery cell.

[0015] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of a cell cover plate provided in an embodiment of the present invention; Figure 2 A schematic structural diagram of a cell cover provided by an embodiment of the present invention from another perspective; Figure 3 For along Figure 2 The cross-section taken at AA in the middle; Figure 4 for Figure 3 A schematic diagram of the enlarged structure at B in the middle; Figure 5 A schematic diagram of the structure of the pole and the riveted piece in the battery cover plate provided by an embodiment of the present invention before riveting; Figure 6 A schematic diagram of the structure of the pole and the riveted piece in the battery cover plate after riveting provided by an embodiment of the present invention; Figure 7 A schematic diagram of the structure of the electrode and the riveted part in the battery cover after welding provided by an embodiment of the present invention.

[0018] Icons: 10-cover body; 11-mounting hole; 12-liquid injection hole; 20-pole; 21-riveted boss; 22-connecting part; 30-rivet part; 31-connecting hole; 311-first step part; 312-second step part; 313-third step part; 41-first insulating part; 42-second insulating part; 50-sealing part; 60-pressure relief part; 70-welding part. DETAILED DESCRIPTION

[0019] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0020] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0021] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0022] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0023] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0024] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0025] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0026] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0027] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0028] According to a first aspect of the present invention, a cell cover is provided, which specifically includes a cover body 10 , a pole 20 and a rivet 30 .

[0029] Hereinafter, the specific structure of the cell cover plate according to the present embodiment as described above will be described.

[0030] In this embodiment, if Figures 1 to 3 As shown, the cover body 10 is formed into a plate-like structure for sealing the opening of the battery cell housing. The cover body 10 can be a polygonal or circular plate-like structure as long as it meets the sealing requirements of the battery cell housing. The cover body 10 is provided with a mounting hole 11 for assembling the pole 20. The mounting hole 11 is formed as a through hole that penetrates the cover body 10.

[0031] In addition, in this embodiment, Figures 1 to 3 As shown, the cover body 10 is also provided with an injection hole 12, which is a through-hole structure penetrating the cover body 10. After the battery cover and the shell are assembled, electrolyte can be injected into the battery cell through the injection hole 12. After the injection is completed, the injection hole 12 can be closed.

[0032] like Figures 1 to 6 As shown, the pole 20 is assembled in the mounting hole 11, and both ends of the pole 20 in the axial direction extend out of the mounting hole 11, wherein the end of the pole 20 located inside the battery cell is used to connect with the pole group arranged inside the battery cell shell. Specifically, the side wall of the end of the pole 20 facing the inside of the battery cell is formed with a connecting portion 22 protruding outward, preferably protruding outward along the radial direction of the pole 20, and the connecting portion 22 can be formed as a plate-like structure arranged parallel to the cover body 10, and the plate-like structure can be polygonal, circular or elliptical.

[0033] It should be noted that the axial direction of the pole 20 is perpendicular to the radial direction of the pole 20 . In this embodiment, the axial direction of the pole 20 is the thickness direction of the cover plate body 10 .

[0034] In this embodiment, the main body of the pole 20 may be a columnar structure with a circular cross section, and the connecting portion 22 may be a plate-like structure with a polygonal, elliptical or circular shape.

[0035] like Figures 1 to 6 As shown, the rivet 30 is formed as a block structure, and a connection hole 31 is opened on the rivet 30. The connection hole 31 is a through-hole structure that penetrates the rivet 30 and is used to fix the connection with the end of the pole 20 extending outside the battery cell; specifically, the pole 20 is riveted to the connection hole 31 and then welded to the rivet 30.

[0036] More specifically, if Figures 4 to 6As shown, the connecting hole 31 is formed as a stepped hole structure having a first step portion 311, a second step portion 312 and a third step portion 313 which are arranged sequentially along the axial direction and whose apertures decrease sequentially, that is, the second step portion 312 is arranged between the first step portion 311 and the third step portion 313, and the aperture of the first step portion 311 is larger than the aperture of the second step portion 312, which is larger than the aperture of the third step portion 313.

[0037] Specifically, in this embodiment, Figure 4 and Figure 6 As shown, part of the side wall of the pole 20 surrounding the axial direction thereof expands toward the second step portion 312 to form a riveted boss 21, and the riveted boss 21 is formed into an annular structure, so that the pole 20 and the rivet 30 are evenly stressed after assembly, thereby ensuring the connection strength between the pole 20 and the rivet 30. Furthermore, in this embodiment, if Figure 5 and 6 As shown, the distance between the axial side wall of the portion of the pole 20 used to form the riveted boss 21 before riveting and the axial side wall of the riveted boss 21 surrounding the pole 20 after riveting is b, b=0.3mm~0.6mm, thereby improving the connection reliability between the pole 20 and the riveted part 30.

[0038] In a preferred embodiment, Figure 6 As shown, in the thickness direction of the cover body 10, the height dimension of the riveted boss 21 is H, H=0.8mm~1.5mm, so as to ensure that the riveted boss 21 has a sufficient material expansion height, so that the pole 20 has sufficient bearing capacity, and avoid the failure of the battery cover due to damage to the pole 20.

[0039] In a preferred embodiment, Figure 6 As shown, in the thickness direction of the cover body 10, the height dimension of the riveted boss 21 is H, and the height dimension of the riveted member 30 is H1, H=(33.3%~66.7%)H1, so that the pole 20 has sufficient bearing capacity. Further, preferably, H1≥2.5mm.

[0040] Next, the dimensions b, H, and H1 of the assembled battery cover are measured, and the strength test of the riveted battery cover is performed, specifically, a thrust test is performed on the pole 20. When the ultimate thrust f that the pole 20 can withstand is not less than 1600N, the test is qualified. In addition, the internal resistance of the riveted battery cover is measured. When the internal resistance R between the surface of the rivet 30 facing away from the cover body 10 and the bottom surface of the pole 20 facing the inside of the battery cell is less than 0.035 mΩ, the internal resistance requirement of the battery cover is met. The test results are shown in Table 1 below.

[0041] Table 1

[0042] Referring to Table 1 above, it can be seen that in Examples 1-1 to 1-9, the dimensions of b, H, H1 and H / H1 are all within the limited ranges described above, and the ultimate thrust f that the pole 20 can withstand after the thrust test is not less than 1600N, indicating that the stress condition of the pole 20 meets the requirements of battery cell use, while in Comparative Examples 1-1 to 1-9, at least one of b, H, H1 and H / H1 is not within the limited ranges described above, so that the connection strength between the riveted pole 20 and the rivet 30 is insufficient and cannot meet the stress requirements of the pole 20, thereby proving the reliability of the parameter ranges defined by b, H, H1 and H / H1 as described above.

[0043] In addition, referring to Table 1, it can be seen that in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-9, the internal resistance R exceeds 0.035 mΩ, which does not meet the use requirements of the battery cover.

[0044] In order to solve the problem of increased internal resistance after riveting, in this embodiment, Figure 7 As shown, after riveting, the pole 20 is welded to the rivet 30 to form a welding portion 70 between the second step portion 312 and the pole 20, thereby reducing the internal resistance of the cell cover after riveting to meet the use requirements. The welding portion 70 can be formed by welding 1 to 3 times, and the welding portion 70 has a penetration depth and a weld width. The welding portion 70 can be understood as a weld mark formed under the welding process. The penetration depth is the depth of the material melted during the welding process, and the weld width is the distance between the two sides of the weld mark during the welding process.

[0045] Affected by the welding process, part of the welding portion 70 may extend out of the surface of the rivet 30 facing away from the cover body 10, thereby affecting the appearance of the battery cover. In the present embodiment, after welding, the flatness of the surface of the rivet 30 facing away from the cover body 10 is less than 0.2 mm, specifically, the height of the welding portion 70 extending out of the first step portion 311 and facing the outside of the battery cell does not exceed 0.2 mm, so as to meet the appearance requirements of the battery cover and improve the yield rate of the battery cell.

[0046] Before riveting Figure 5 As shown, the pole 20 is adapted to the size of the third step portion 313, and after riveting, Figure 4As shown in the figure, the end of the pole 20 expands outward to extend toward the second step portion 312, so as to be riveted with the boss located between the second step portion and the third step portion. After riveting, the pole 20 is welded to the second step portion 312; the first step portion 311 is arranged at one end of the rivet 30 facing away from the cover plate body 10, and in the thickness direction of the cover plate body 10, the height dimension of the first step portion 311 is h, h=0.2mm~0.5mm, so as to avoid the weld mark formed by the welding process protruding from the upper surface of the rivet 30, thereby ensuring the flatness of the rivet 30, and avoiding the size of b being too large to occupy the battery cell space and cause energy loss, preferably, h=0.2mm or 0.3mm, so as to avoid the height of the first step portion 311 The dimension is too large, occupying the space of the battery cell in the thickness direction of the cover body 10; in the radial direction of the connecting hole 31 (i.e., perpendicular to the thickness direction of the cover body 10), the distance between the inner wall of the first step portion 311 and the inner wall of the second step portion 312 is a, a=0.5mm~1mm, so as to avoid the weld mark (i.e., the welding portion 70 as described above) formed by the welding process from excessively protruding from the upper surface of the rivet 30, thereby ensuring the flatness of the rivet 30, and avoiding the size of a being too large to occupy the battery cell space and cause energy loss. Preferably, a=0.8mm or 1mm, which meets the requirements of the laser welding process, ensures the welding quality, and also effectively avoids the influence of the laser welding process on the appearance of the rivet 30 to a certain extent.

[0047] In addition, welding may cause excessive melting of part of the riveted boss 21, thereby reducing the strength of the pole 20 and easily causing the cell cover to fail. In this embodiment, Figure 7 As shown, the penetration depth of the welding portion 70 is B, in mm, and B / H=50%~80%. This ensures that the welding strength effectively reduces the internal resistance and avoids the problem that the welding process cannot meet the force requirements of the pole 20.

[0048] Next, a, h, H, B of the battery cover after welding and the flatness of the side of the rivet 30 facing away from the cover body 10 are measured, and the strength test of the battery cover after welding is carried out, specifically, a thrust test is carried out on the pole 20. When the ultimate thrust f that the pole 20 can withstand is not less than 1600N, it is considered to be qualified. In addition, the internal resistance of the battery cover after riveting is measured. When the internal resistance R between the surface of the rivet 30 facing away from the cover body 10 and the bottom surface of the pole 20 facing the inside of the battery cell is less than 0.035 mΩ, the internal resistance requirement of the battery cover is met. The test results are shown in Table 2 below.

[0049] Table 2

[0050] Referring to Table 2 above, it can be seen that in Examples 2-1 to 2-9, a, h, B / H and the flatness dimensions of the side of the rivet 30 facing away from the cover body 10 are all within the above-mentioned limited range, and the ultimate thrust f that the pole 20 can withstand after the thrust test is not less than 1600N, and the internal resistance R is lower than 0.035 mΩ, indicating that the stress condition of the pole 20 and the internal resistance of the cell cover meet the use requirements of the cell, while in Comparative Examples 2-1 to 2-9, at least one of b, H, H1 and H / H1 is not within the above-mentioned limited range, and the ultimate thrust f that the pole 20 can withstand after welding is less than 1600N and / or the internal resistance R exceeds 0.035 The problem of increased mΩ and / or flatness of the rivet 30 makes the stress condition of the pole 20 and / or the internal resistance of the cell cover and / or the appearance quality of the cell cover unable to meet the use requirements of the cell, thereby proving the reliability of the dimensional limitations on a, h, B / H and the flatness of the side of the rivet 30 facing away from the cover body 10 as described above.

[0051] It should be noted that, in this embodiment, Figures 1 to 3 As shown, the number of poles 20 on the cover body 10 can be one or more. When the number of poles 20 is one, the pole 20 can be a positive pole or a negative pole. When the pole 20 is a positive pole, the battery cover is a positive cover, and when the pole 20 is a negative pole, the battery cover is a negative cover; when the number of poles 20 is multiple, some of the multiple poles 20 are positive poles and the remaining poles 20 are negative poles.

[0052] In addition, in this embodiment, Figures 1 to 6 As shown, the cell cover also includes a first insulating member 41 and a second insulating member 42, which are arranged between the cover body 10 and the rivet 30. Part of the first insulating member 41 is coated on the rivet 30 and is arranged around the axial circumferential side wall of the pole 20 to form insulation protection for the cover body 10 to avoid metal overlap between the cover body 10 and the rivet 30 to cause a short circuit. The first insulating member 41 can be formed into a ring structure and is arranged one by one with the pole 20. The second insulating member 42 is arranged on the side of the cover body 10 facing the inside of the cell to form insulation protection for the end of the cover body 10 facing the inside of the cell. When the cover body 10 is a rectangular sheet structure, the second insulating member 42 can be formed into a strip structure extending along the length direction of the cover body 10. Part of the second insulating member 42 is sandwiched between the connecting portion 22 and the cover body 10, so as to further form insulation protection for the cover body 10.

[0053] In this embodiment, the first insulating member 41 is made of PPS (polyphenylene sulfide) material, and the second insulating member 42 is made of PP (polypropylene) material.

[0054] In this embodiment, if Figures 3 to 6 As shown, the cell cover also includes a seal 50, which can be a sealing ring made of fluororubber material. The seal 50 is formed into an annular structure that is sleeved on the pole 20 and surrounds the pole 20 in the axial direction. In the thickness direction of the cover body 10, part of the seal 50 is sandwiched between the connecting portion 22 and the cover body 10, so as to ensure the sealing of the cell cover assembly and avoid leakage, seepage, etc. of the cell; the remaining part of the seal 50 extends between the mounting hole 11 and the pole 20 to fill the gap between the mounting hole 11 and the pole 20 to ensure the sealing reliability.

[0055] In this embodiment, if Figures 3 to 6 As shown, the seal 50 is crimped with the first insulating member 41 and / or the second insulating member 42 to improve the insulation sealing effect. Preferably, the seal 50 is crimped with the first insulating member 41 and the second insulating frame respectively to completely separate the pole 20 from the cover body 10 while ensuring the sealing, thereby meeting the insulation requirements of the cover body 10.

[0056] In addition, in this embodiment, Figures 1 to 3 As shown, the battery cover also includes a pressure relief member 60. An exhaust hole is opened on the cover body 10. The pressure relief member 60 is assembled in the exhaust hole. When the battery cell fails and produces gas, the pressure inside the battery cell increases to a preset opening pressure of the pressure relief member 60. The pressure relief member 60 opens to connect the inside and outside of the battery cell. In this way, the gas inside the battery cell is discharged to relieve pressure, thereby ensuring the safety of the battery cell and avoiding risks such as explosion and fire.

[0057] In this embodiment, the pressure relief member 60 may be an explosion-proof valve.

[0058] According to a battery cell cover provided by the present invention, a connecting hole is provided on a rivet, and a pole is riveted to the connecting hole and then welded to the rivet; the connecting hole is formed into a stepped hole structure having a first step portion, a second step portion and a third step portion which are sequentially arranged along the axial direction and whose apertures decrease sequentially, the pole and the second step portion are first riveted and then welded, and the first step portion is provided at an end of the rivet facing away from the cover body by limiting the height dimension h=0.2mm~0.5mm of the first step portion, thereby avoiding the weld mark formed by the welding process from protruding from the upper surface of the rivet, thereby ensuring the flatness of the rivet; in addition, the distance a=0.5mm~1mm between the inner wall of the first step portion and the inner wall of the second step portion is also limited, so that an avoidance groove required by the welding process is formed on the rivet, thereby improving the influence of the welding process on the shape accuracy and dimensional accuracy of the rivet to a certain extent, thereby improving the appearance yield of the battery cell cover.

[0059] A battery cell provided according to the present invention comprises the battery cell cover as described above, and the connection strength between the pole and the rivet in the battery cell cover and the appearance yield are effectively improved, thereby also being able to improve the safety and yield of the battery cell to a certain extent.

[0060] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell cover, characterized in that: The battery cover plate comprises: The cover plate body is provided with a mounting hole; A pole, mounted in the mounting hole; A rivet is provided with a connection hole, the pole is riveted to the connection hole and then welded to the rivet; the connection hole is formed into a stepped hole structure having a first step portion, a second step portion and a third step portion which are sequentially arranged along the axial direction and whose hole diameters decrease sequentially; the pole is welded to the second step portion, and the first step portion is arranged at an end of the rivet facing away from the cover plate body; In the thickness direction of the cover plate body, the height dimension of the first step portion is h, h=0.2mm~0.5mm; in the radial direction of the connecting hole, the distance between the inner wall of the first step portion and the inner wall of the second step portion is a, a=0.5mm~1mm.

2. The cell cover plate according to claim 1, characterized in that: A portion of the side wall of the pole which is arranged in the axial direction of the pole is expanded toward the second step portion to form a riveted boss, and the riveted boss is formed into an annular structure.

3. The cell cover plate according to claim 2, characterized in that: The distance between the part of the side wall on the pole before riveting and the side wall on the riveting boss surrounding the axial direction of the pole after riveting is b, b=0.3mm~0.6mm.

4. The battery cover according to claim 2, characterized in that: In the thickness direction of the cover plate body, the height dimension of the riveted boss is H, H=0.8mm~1.5mm.

5. The cell cover plate according to claim 2, characterized in that: In the thickness direction of the cover plate body, the height dimension of the riveted boss is H, in mm; in the thickness direction of the cover plate body, the height dimension of the riveted part is H1, H= (33.3%~66.7%) H1.

6. The cell cover plate according to claim 5, characterized in that: H1≥2.5mm.

7. The cell cover plate according to claim 5, characterized in that: After riveting, the pole is welded to the riveted piece to form a welding portion between the second step portion and the pole, and the penetration depth of the welding portion is B, in mm, and B / H=50%~80%.

8. The cell cover plate according to claim 1, characterized in that: After welding, the flatness of the surface of the rivet facing away from the cover plate body is less than 0.2 mm.

9. The cell cover plate according to claim 1, characterized in that: A connecting portion protruding outwardly in the radial direction of the pole is formed on a side wall of one end of the pole facing the inside of the battery core; The battery cover plate also includes: A first insulating member, disposed between the cover plate body and the rivet member, wherein a portion of the first insulating member is covered on the rivet member and is disposed around the axial circumferential side wall of the pole; A second insulating member is disposed on a side of the cover body facing the inside of the battery cell, and a portion of the second insulating member is sandwiched between the connecting portion and the cover body; The sealing member is formed into an annular structure which is sleeved on the pole and surrounds the pole in the axial direction; part of the sealing member is sandwiched between the connecting portion and the cover plate body, and part of the sealing member extends between the mounting hole and the pole.

10. A battery cell, characterized in that: The invention comprises a cell cover plate as described in any one of claims 1 to 9.

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