Cover plate and battery cell

Abstract

The invention provides a cover plate and a battery cell, the cover plate comprises a cover plate body and a pole assembly, and the pole assembly comprises a pole body and a riveting block located on one side, far away from a pole group, of the cover plate body; the pole body and the riveting block respectively comprise a riveting part and a riveting hole which are riveted and sleeved with each other; at the end part far away from the pole group, an accommodating space is formed between the riveting part and the riveting hole, and an insulating structure is arranged in the accommodating space, so that the outer peripheral surface of the riveting part is in insulated connection with the inner peripheral surface of the riveting hole. On one hand, insulation between copper and aluminum at the riveting part of the riveting part of the copper material and the riveting hole of the aluminum material is realized, and even if the riveting part of the copper and the aluminum is exposed in the air, potential difference between the copper and the aluminum can be well avoided, so that the end face, far away from the pole group, of the riveting block cannot be oxidized and corroded in severe environments such as condensation and salt mist, and the service life of the riveting block is prolonged. The structural strength of the cover plate is ensured; and on the second aspect, the riveting part and the riveting hole can be connected together through the insulating structure, so that the structural strength of the cover plate is further ensured.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate and a battery cell including the cover plate. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supply, power storage, new energy storage power supply, aerospace and military industry due to their advantages such as large capacity, high operating voltage, strong charge retention capability and long cycle life.

[0003] The cover plate includes a cover plate body and a terminal post assembly. The terminal post assembly includes a terminal post body that passes through the cover plate body and a riveting block located on the side of the cover plate body away from the electrode assembly. The terminal post body and the riveting block are connected by press-fitting (i.e., riveting). However, in the above-mentioned cover plate structure, especially for the negative electrode cover plate, since the riveting block is generally made of aluminum and the negative electrode post is usually made of copper, during the long-term use of the battery cell, especially energy storage cells, they often encounter harsh environments such as condensation and salt spray. In environments such as salt spray, there is a potential difference between the copper and aluminum riveting points, forming a potential couple. This leads to rapid oxidation and corrosion of the aluminum riveting block, reducing the structural strength of the cover plate and affecting the safety performance of the battery cell and energy storage box. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a cover plate and a battery cell that solves the problem that the rivet block is easily oxidized and corroded in harsh environments.

[0005] To achieve the above objectives, this application provides the following technical solution: A cover plate includes a cover plate body and an electrode assembly, the electrode assembly including an electrode body passing through the cover plate body and a rivet block located on the side of the cover plate body away from the electrode assembly. The pole body and the riveting block each include a riveting part and a riveting hole that are riveted together; at the end away from the pole group, an accommodating space is formed between the riveting part and the riveting hole, and an insulating structure is provided in the accommodating space so that the outer peripheral surface of the riveting part is insulated from the inner peripheral surface of the riveting hole.

[0006] Optionally, in the above cover plate, the riveting block includes a riveting hole, the riveting hole being connected to the end side of the riveting hole away from the pole group; the diameter of the riveting hole is larger than the diameter of the riveting hole, and a first stepped surface is formed at the connection between the two; The insulating structure includes a first portion located within the accommodating space and a second portion connected to the first portion; on the end side away from the pole group, the second portion covers the riveting seam between the riveting portion and the riveting hole.

[0007] Optionally, in the above cover plate, the second part is a hollow annular structure, the inner ring of the second part is located on the end side of the riveted part away from the pole group, and the outer ring of the second part is located on the first stepped surface.

[0008] Optionally, in the above cover plate, the inner peripheral surface of the end of the riveting hole away from the pole group is formed with a countersunk groove extending radially outward along the riveting hole, and the countersunk groove and the outer peripheral surface of the riveting part form the accommodating space.

[0009] Optionally, in the above cover plate, the width of the accommodating space along the radial direction of the rivet hole is w, where 0.45mm≤w≤0.6mm.

[0010] Optionally, in the above cover plate, along the thickness direction of the cover plate, the height of the accommodating space is h, and the height of the riveting hole is H; 0.35≤h / H≤0.45, and / or, 1.3mm≤H≤1.5mm.

[0011] Optionally, in the above cover plate, the end side of the riveting portion away from the pole group is formed with a pre-riveting hole that is recessed toward the pole group; Along the thickness direction of the cover plate: the pre-riveting hole has a first end side close to the pole group, the riveting hole has a second end side close to the pole group, the first end side is closer to the pole group than the second end side, and the distance between the first end side and the second end side is c, where c < 1 mm.

[0012] Optionally, in the above-mentioned cover plate, the insulating structure is an injection-molded insulating structure.

[0013] Optionally, in the above-mentioned cover plate, from the side away from the pole group to the side closer to the pole group, the inner peripheral surface of the pre-riveting hole of the riveting part is inclined towards the direction close to the central axis of the riveting part; wherein, before the pole body is riveted to the riveting block: Along the thickness direction of the cover plate, the depth of the pre-riveting hole is A, where 1mm ≤ A ≤ 1.5mm; And / or, The wall thickness of the pre-riveting hole at the end furthest from the pole group is T, where 1.2mm ≤ T ≤ 2.5mm; And / or, The inclination angle of the inner circumferential surface of the pre-riveting hole is γ, where 10°≤γ≤25°.

[0014] A battery cell includes a housing, an electrode assembly disposed within the housing, and a cover plate as described above that covers an opening in the housing.

[0015] In the cover plate and battery cell of this application, after the pole body and the riveting block are riveted together, the area between the riveting part and the riveting hole includes: ① a riveting mating area close to the pole group; ② a accommodating space away from the pole group. Since this application reserves an accommodating space at the end of the riveting part away from the pole group between the riveting part and the riveting hole, an insulating structure can be set in the accommodating space, and the outer peripheral surface of the riveting part and the inner peripheral surface of the riveting hole can be insulated from each other through the insulating structure. In this way, firstly, the insulation between the copper and aluminum at the riveting part of the copper material and the riveting hole of the aluminum material is achieved. Even if the copper and aluminum riveting joint is exposed to the air, the potential difference between the copper and aluminum can be well avoided. Therefore, the end face of the riveting block away from the pole group will not be oxidized and corroded in harsh environments such as condensation and salt spray, thereby ensuring the structural strength of the cover plate. Secondly, the insulating structure can connect the riveting part and the riveting hole together, further ensuring the structural strength of the cover plate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the pole body before riveting, according to an embodiment of this application.

[0018] Figure 2 for Figure 1 A cross-sectional view parallel to the front view.

[0019] Figure 3 for Figure 1 Top view.

[0020] Figure 4 This is a schematic diagram of the structure of the riveting block according to an embodiment of this application.

[0021] Figure 5 This is a cross-sectional view of the pole assembly of the cover plate before the insulation structure is installed in an embodiment of this application.

[0022] Figure 6 This is a cross-sectional view of the pole assembly of the cover plate after the insulation structure is provided in an embodiment of this application.

[0023] Figure 7 for Figure 6 A magnified view of part A in the middle.

[0024] superior Figures 1-7 middle: 1. Cover plate body; 2. Terminal post assembly; 3. Terminal post body; 4. Riveting block; 5. Insulation structure; 6. Terminal post base plate; 7. Upper plastic; 8. Lower plastic; 31. Riveting part; 32. Pre-riveting hole; 33. Mating part 41. Riveting hole; 42. Riveting press hole; 43. First step surface; 44. Mating hole; 51. Part One; 52. Part Two; 411. Settling Platform / Trench. Detailed Implementation

[0025] This application provides a cover plate and a battery cell, which solves the problem that the rivet block is easily oxidized and corroded in harsh environments.

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] like Figures 1-7 As shown, this application embodiment provides a cover plate for sealing the opening of the battery cell housing; the electrode assembly is disposed in the internal space enclosed by the housing. The cover plate includes a cover plate body 1 and an electrode post assembly 2; the electrode post assembly 2 includes an electrode post body 3 and a riveting block 4. The electrode post body 3 and the riveting block 4 respectively include a riveting portion 31 and a riveting hole 41 riveted together; at the end away from the electrode group, a receiving space a is formed between the riveting portion 31 and the riveting hole 41, and an insulating structure 5 is provided in the receiving space a so that the outer peripheral surface of the riveting portion 31 is insulated from the inner peripheral surface of the riveting hole 41.

[0028] It should be noted that "end side" refers to a surface without extended length, while "end point" refers to a segment with extended length. For example, the end side of the riveting part 31 away from the pole group is the end face of the riveting part 31 away from the pole group; the end point of the riveting part 31 away from the pole group is the segment of the riveting part 31 extending from the end side away from the pole group towards the end side closer to the pole group. The understanding of end side and end point for other components is the same, and will not be elaborated here.

[0029] Please see Figure 5The cover plate includes an upper plastic 7 and a lower plastic 8. The upper plastic 7 is located on the end face of the cover plate body 1 away from the electrode assembly, and the upper plastic 7 forms an insulating space. The riveting block 4 is located in the insulating space. The lower plastic 8 is located on the end face of the cover plate body 1 near the electrode assembly. The electrode post assembly 2 also includes an electrode post base plate 6, which is connected to the end side of the electrode post body 3 near the electrode assembly. The electrode post base plate 6 is located on the side of the cover plate body 1 near the electrode assembly and abuts against the lower plastic 8. The electrode post body 3 passes through the lower plastic 8, the cover plate body 1, the upper plastic 7, and the riveting block 4 in sequence. The electrode post body 3 and the electrode post base plate 6 are integrally connected structures.

[0030] Please see Figure 4 It should be further explained that the end of the riveting hole 41 near the electrode assembly is connected to a mating hole 44, the diameter of which is smaller than that of the riveting hole 41. The electrode body 3 includes a sleeve portion fitted onto the riveting block. For example, before the electrode body 3 is riveted to the riveting block 4, the outer diameter of the sleeve portion is consistent with the inner diameter of the mating hole 44; optionally, the end of the sleeve portion away from the electrode assembly extends out of the riveting block 4. When the electrode body 3 and the riveting block 4 are riveted, a riveting press is used to rivet the end of the sleeve portion away from the electrode assembly towards the electrode assembly. The end of the sleeve portion away from the electrode assembly will undergo axial compression deformation and radial expansion deformation, thereby riveting the material until it is riveted to the riveting hole 41 for connection. Please refer to... Figure 5 After the pole body 3 is riveted to the riveting block 4, the sleeve part includes a mating part 33 that is sleeved with the mating hole 44, and a riveting part 31 that is sleeved and riveted with the riveting hole 41.

[0031] This cover plate can be used to form a positive electrode cover plate for the positive terminal of the battery cell; of course, this cover plate can also be used to form a negative electrode cover plate for the negative terminal of the battery cell. Optionally, the cover plate of this application is specifically used for the negative terminal of the battery cell, the electrode post body 3 is made of copper material, which is the same material as the negative electrode tab; the riveting block 4 is made of aluminum material.

[0032] After the pole body 3 and the riveting block 4 are riveted together, the riveting part 31 and the riveting hole 41 include: ① a riveting mating area close to the pole group; ② a accommodating space a away from the pole group. Since the present application reserves an accommodating space a at the end of the riveting part 31 away from the pole group, an insulating structure 5 can be set in the accommodating space a, and the outer peripheral surface of the riveting part 31 and the inner peripheral surface of the riveting hole 41 can be insulated from each other through the insulating structure 5. In this way, firstly, the insulation between the copper and aluminum at the riveting part 31 of the copper material and the riveting hole 41 of the aluminum material is achieved. In this way, even if the copper and aluminum riveting joint is exposed to the air, the potential difference between the copper and aluminum can be well avoided. In this way, the end face of the riveting block 4 away from the pole group will not be oxidized and corroded in harsh environments such as condensation and salt spray, thereby ensuring the structural strength of the cover plate. Secondly, the insulating structure 5 can connect the riveting part 31 and the riveting hole 41 together, further ensuring the structural strength of the cover plate.

[0033] In some embodiments of this application, please refer to Figure 4 The riveting block 4 includes a riveting hole 42, which is connected to the end of the riveting hole 41 away from the pole group. The diameter of the riveting hole 42 is larger than the diameter of the riveting hole 41, and a first stepped surface 43 is formed at the connection between the riveting hole 41 and the riveting hole 42. Please refer to [link / reference]. Figure 5 , Figure 6 , Figure 7 The insulating structure 5 includes a first portion 51 located within the accommodating space a, and a second portion 52 connected to the first portion 51; on the end side away from the pole group, the second portion 52 covers the riveting seam between the riveting portion 31 and the riveting hole 41.

[0034] As described above, the first part 51 prevents direct contact between the copper and aluminum of the riveting part 31 and the riveting hole 41; the second part 52 forms an insulating cover for the riveting seam, preventing contact between the external environment and the riveting seam. The dual protection of the first part 51 and the second part 52 can better prevent oxidation and corrosion of the cover plate, ensuring the structural strength of the cover plate. Furthermore, the second part 52 further enhances the fixed connection strength between the riveting part 31 and the riveting hole 41, ensuring the reliability of the cover plate in use.

[0035] Please see Figure 7 In some embodiments of this application, the second part 52 is a hollow annular structure, the inner ring of the second part 52 is located on the end side of the riveting part 31 away from the pole group, and the outer ring of the second part 52 is located on the first stepped surface 43.

[0036] As shown above, an insulating structure 5 with a "T" shaped cross section is formed; the second annular part 52 can not only cover the riveting seam, but also achieve minimal material consumption, saving costs while ensuring the effect.

[0037] Please see Figure 4 In some embodiments of this application, the inner peripheral surface of the end of the riveting hole 41 away from the pole assembly is formed with a countersunk groove 411 extending radially outward along the riveting hole 41; see also Figure 5 The recessed groove 411 and the outer peripheral surface of the riveting part 31 form the accommodating space a.

[0038] The structure of opening a countersunk groove 411 on the inner circumferential surface of the rivet hole 41 is simple and easy to process and produce. While forming the accommodating space a, the rivet part 31 does not need to be reduced in material, thus ensuring the rivet strength between the pole body 3 and the rivet block 4.

[0039] In some parallel embodiments, the outer peripheral surface of the end of the riveting portion 31 away from the pole group is formed with a stepped area extending radially inward along the riveting portion 31, and the stepped area and the inner peripheral surface of the riveting hole form an accommodating space a. As described above, the structural types for forming the accommodating space a are further enriched, and can be selected according to actual needs, with strong flexibility and applicability.

[0040] Please see Figure 4 In some embodiments of this application, the width of the accommodating space a along the radial direction of the riveting hole 41 is w, 0.45mm≤w≤0.6mm; for example, w can be any of 0.45mm, 0.5mm, 0.55mm, 0.6mm, etc.

[0041] It should be noted that the shape of the accommodating space a constrains the shape of the insulating structure 5; the accommodating space a can be a regular shape or an irregular shape. The recessed groove 411 is a regular shape, and the width of the recessed groove 411 is consistent along the thickness direction of the cover plate, ranging from 0.45mm to 0.6mm.

[0042] In this way, the thickness of the first part 51 of the insulation structure 5 is limited to a reasonable range, which can avoid the first part 51 being too thin, which would prevent the insulation between the copper and aluminum at the riveting point from being properly achieved; and it can also avoid the first part 51 being too thick, which would affect the strength of the riveting structure.

[0043] Please see Figure 6 In some embodiments of this application, along the thickness direction of the cover plate, the height of the accommodating space a is h, and the height of the riveting hole 41 is H; 0.35≤h / H≤0.45; for example, h / H can be any one of 0.35, 0.4, 0.45, etc.

[0044] As shown above, after the pole body 3 and the riveting block 4 are riveted together, the height of the first part 51 and the height of the riveting hole 41 are limited to a reasonable range. This can prevent the height of the first part 51 from being too small, which would prevent the insulation between the copper and aluminum at the riveting point from being properly achieved; and it can also prevent the height of the first part 51 from being too large, which would affect the strength of the riveting structure.

[0045] Please see Figure 6 In some parallel embodiments, 1.3mm ≤ H ≤ 1.5mm; for example, H can be any of 1.3mm, 1.4mm, 1.5mm, etc.

[0046] In this way, the height of the riveting hole 41 is limited to a reasonable range, which can avoid the height being too small, thus affecting the strength of the riveting structure; at the same time, it can also avoid the height being too large, thus making it difficult to bulge the riveting part 31, increasing the riveting difficulty and affecting the riveting yield.

[0047] Please see Figure 6 In some embodiments of this application, the riveting portion 31 has a pre-riveting hole 32 recessed towards the pole group on the end side away from the pole group. Along the thickness direction of the cover plate: the pre-riveting hole 32 has a first end side close to the pole group, and the riveting hole 41 has a second end side close to the pole group. The first end side is closer to the pole group than the second end side. The distance between the first end side and the second end side is c, where c < 1 mm; for example, c can be any one of 0.9 mm, 0.8 mm, 0.6 mm, etc.

[0048] In this way, the pre-riveting hole 32 can be guaranteed to have a certain depth, which makes it easier for the rivet head of the riveting machine to insert into the pre-riveting hole 32 and rivet downwards, so that the riveting part 31 can undergo better radial deformation, without making the depth of the pre-riveting hole 32 too large, which would affect the structural strength of the pole body 3 and thus affect the riveting fixing strength.

[0049] In some embodiments of this application, the insulation structure 5 is an injection-molded insulation structure.

[0050] After the pole body 3 is riveted to the riveting block 4, plastic is injected into the accommodating space a by an injection molding machine, and after cooling and molding, an insulating structure 5 is formed that is injection molded to connect with the riveting part 31 and the riveting hole 41. As shown above, the insulating structure 5 is not only simple in structure and easy to process and mold, but also can ensure the fixed connection strength between the riveting part 31 and the riveting hole 41, and ensure the reliability of the cover plate.

[0051] To ensure that the cover plate, once assembled onto the battery cell, effectively achieves the functions and effects described above, its dimensions must be within the parameter range specified above. Table 1 presents experimental data for some embodiments and comparative examples. Wherein: w: Width of the accommodating space a along the radial direction of the riveting hole 41; h: The height of the accommodating space a along the thickness direction of the cover plate; H: Height of the rivet hole 41 along the thickness direction of the cover plate; c: The height difference between the first end of the pre-riveting hole 32 near the pole group and the second end of the riveting hole 41 near the pole group.

[0052] Table 1 As can be seen from Table 1, when the width and height of the accommodating space a, as well as the ratio of the height of the accommodating space to the height of the riveting hole and the height of the riveting hole, are within the parameter range defined in the above embodiments, after the salt spray test of the battery cell, the aluminum surface at the copper-aluminum riveting joint of the metallographic inspection cover plate shows no obvious corrosion. However, when the width or height of the accommodating space a is insufficient, the cover plate will still have corrosion problems. In addition, if the depth of the pre-riveting hole 32 of the pole body 3 is too large, it will affect the structural strength of the cover plate.

[0053] Please see Figures 1-3 In some embodiments of this application, a pre-riveting hole 32 is formed on the end side of the riveting portion 31 that is away from the electrode group and recessed towards the electrode group. From the side away from the electrode group to the side near the electrode group, the inner peripheral surface of the pre-riveting hole 32 is inclined towards the direction close to the central axis of the electrode body 3.

[0054] When the cover plate is placed above the pole group, the pre-riveting hole 32 is a tapered hole with a larger top and a smaller bottom. When the rivet head of the pre-riveting machine is inserted into the pre-riveting hole 32 and riveted downward, the circumferential wall of the pre-riveting hole 32 can undergo better radial deformation, which makes it easier for the riveting part 31 to be riveted and expanded to be riveted and fixed with the riveting hole 41 of the riveting block 4, thereby improving the riveting yield.

[0055] Please see Figure 2 In some embodiments, the depth of the pre-riveting hole 32 along the thickness direction of the cover plate is A, where 1mm≤A≤1.5mm; for example, A can be any one of 1mm, 1.3mm, 1.5mm, etc.

[0056] As mentioned above, limiting the depth of the pre-riveting hole 32 to a reasonable range not only avoids the radial riveting expansion of the riveting part 31 due to the excessive depth of the pre-riveting hole 32, thus reducing the riveting strength and affecting the riveting yield; but also avoids the structural strength of the pole body 3 being too weak due to the excessive depth of the pre-riveting hole 32, which would affect the riveting strength between the pole body 3 and the riveting block 4, and thus affect the reliability of the cover plate.

[0057] Please see Figure 3 In some embodiments, the wall thickness of the end of the pre-riveting hole 32 away from the pole group is T, where 1.2mm≤T≤2.5mm; for example, T can be any one of 1.2mm, 2mm, 2.5mm, etc.

[0058] The wall thickness of the end of the pre-riveting hole 32 furthest from the pole group is the minimum wall thickness of the pre-riveting hole 32, corresponding to the part with the largest diameter of the tapered pre-riveting hole 32. The surrounding wall of the pre-riveting hole 32 is formed of the solid material of the riveting part 31.

[0059] As mentioned above, limiting the minimum wall thickness of the pre-riveting hole 32 to a reasonable range not only avoids the phenomenon of damage to the riveting part 31 during the riveting process due to the minimum wall thickness of the pre-riveting hole 32 being too small, thus causing riveting failure and generating scrap; but also avoids the minimum wall thickness of the pre-riveting hole 32 being too large, which would result in a small radial deformation of the riveting part 31, thereby affecting the riveting material expansion effect and the riveting yield.

[0060] Please see Figure 2 In some embodiments, the inclination angle of the inner circumferential surface of the pre-riveting hole 32 is γ, 10°≤γ≤25°; for example, γ can be any one of 10°, 20°, 25°, etc.

[0061] As mentioned above, limiting the inclination angle (i.e., taper) of the pre-riveting hole 32 to a reasonable range not only avoids excessive axial deformation of the riveting part 31 due to an excessively small inclination angle, but also avoids excessive radial deformation of the riveting part 31 due to an excessively large inclination angle, which would be detrimental to riveting with the riveting block 4. Setting the inclination angle of the inner circumferential surface of the pre-riveting hole 32 to 10°–25° can control the axial and radial deformation of the riveting part 31 to a suitable range, thereby improving the riveting firmness.

[0062] In summary, this application also provides a battery cell, which includes a housing, an electrode assembly disposed within the housing, and a cover plate as described above that seals the opening of the housing.

[0063] Since the battery cell of this application includes the cover plate described above, the beneficial effects of the cover plate on the battery cell are described above and will not be repeated here.

[0064] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0065] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0066] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0067] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0068] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A cover plate, characterized in that, It includes a cover plate body and an electrode assembly, the electrode assembly including an electrode body passing through the cover plate body and a riveting block located on the side of the cover plate body away from the electrode assembly; The pole body and the riveting block each include a riveting part and a riveting hole that are riveted together; at the end away from the pole group, an accommodating space is formed between the riveting part and the riveting hole, and an insulating structure is provided in the accommodating space so that the outer peripheral surface of the riveting part is insulated from the inner peripheral surface of the riveting hole.

2. The cover plate according to claim 1, characterized in that, The riveting block includes a riveting hole, which is connected to the end of the riveting hole away from the pole group; the diameter of the riveting hole is larger than the diameter of the riveting hole, and a first stepped surface is formed at the connection between the two. The insulating structure includes a first portion located within the accommodating space and a second portion connected to the first portion; on the end side away from the pole group, the second portion covers the riveting seam between the riveting portion and the riveting hole.

3. The cover plate according to claim 2, characterized in that, The second part is a hollow annular structure. The inner ring of the second part is located on the end of the riveted part away from the pole group, and the outer ring of the second part is located on the first stepped surface.

4. The cover plate according to claim 1, characterized in that, The inner peripheral surface of the end of the riveting hole away from the pole group is formed with a countersunk groove extending radially outward along the riveting hole, and the countersunk groove and the outer peripheral surface of the riveting part form the accommodating space.

5. The cover plate according to claim 1, characterized in that, Along the radial direction of the rivet hole, the width of the accommodating space is w, where 0.45mm ≤ w ≤ 0.6mm.

6. The cover plate according to claim 4, characterized in that, Along the thickness direction of the cover plate, the height of the accommodating space is h, and the height of the riveting hole is H; 0.35≤h / H≤0.45, and / or, 1.3mm≤H≤1.5mm.

7. The cover plate according to claim 1, characterized in that, The end of the riveting portion away from the pole group has a pre-riveting hole that is recessed toward the pole group; Along the thickness direction of the cover plate: the pre-riveting hole has a first end side close to the pole group, the riveting hole has a second end side close to the pole group, the first end side is closer to the pole group than the second end side, and the distance between the first end side and the second end side is c, where c < 1 mm.

8. The cover plate according to any one of claims 1-7, characterized in that, The insulation structure is an injection-molded insulation structure.

9. The cover plate according to claim 1, characterized in that, From the side furthest from the pole group to the side closest to the pole group, the inner circumferential surface of the pre-riveting hole of the riveting part is inclined toward the direction close to the central axis of the riveting part; wherein, before the pole body is riveted to the riveting block: Along the thickness direction of the cover plate, the depth of the pre-riveting hole is A, where 1mm ≤ A ≤ 1.5mm; And / or, The wall thickness of the pre-riveting hole on the side furthest from the pole group is T, where 1.2mm ≤ T ≤ 2.5mm; And / or, The inclination angle of the inner circumferential surface of the pre-riveting hole is γ, where 10°≤γ≤25°.

10. A battery cell, characterized in that, It includes a housing, an electrode assembly disposed within the housing, and a cover plate as described in any one of claims 1-9 that covers the opening of the housing.

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