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; the pole body and the riveting block respectively comprise a sleeving part and a sleeving hole which are sleeved with each other; the sleeving hole comprises a first hole section, a second hole section and a third hole section which are connected in sequence, a riveting part capable of being riveted with the second hole section in a sleeving manner is formed at the end part, far away from the pole group, of the sleeving part; and an insulating layer is at least arranged between the outer peripheral surface of the riveting part and the inner peripheral surface of the second hole section at the end part far away from the pole group. Therefore, after the pole body is riveted with the riveting block, copper and aluminum at the riveting part of the copper material and the second hole section of the aluminum material are insulated and isolated by the insulating layer, and even if the riveting part of the copper and the aluminum is exposed in the air, potential difference generated between the copper and the aluminum can be well avoided; furthermore, 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 structural strength of the cover plate is 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 riveted together (i.e., riveted). 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 respectively include a sleeve portion and a sleeve hole that are nested together; the sleeve hole includes a first hole segment, a second hole segment and a third hole segment that are connected in sequence and whose diameters decrease in sequence from the side away from the pole group to the side closer to the pole group; the end of the sleeve portion away from the pole group forms a riveting portion that can be nested and riveted with the second hole segment. At least at the end furthest from the pole group, an insulating layer is provided between the outer peripheral surface of the riveting portion and the inner peripheral surface of the second hole segment.

[0006] Optionally, in the above-mentioned cover plate, the outer peripheral surface of the end of the riveted portion away from the pole group is formed with a stepped area that is recessed radially inward, and the insulating layer includes a first insulating layer disposed in the stepped area.

[0007] Optionally, in the above-mentioned cover plate, before the pole body is riveted to the riveting block, along the thickness direction of the cover plate: The height of the first insulating layer is h1; The height of the second hole section from the end near the pole group to the end of the riveting part away from the pole group is H1; 0.3≤h1 / H1≤0.45, and / or, 2.4mm≤H1≤2.8mm.

[0008] Optionally, in the above-mentioned cover plate, after the pole body is riveted to the riveting block, along the thickness direction of the cover plate: The height of the first insulating layer is h2; The height of the second hole section from the end near the pole group to the end of the riveted part away from the pole group is H2; 0.35≤h2 / H2≤0.45, and / or, 0.9mm≤H2≤1.2mm.

[0009] Optionally, in the cover plate described above, the inner peripheral surface of the end of the second hole segment away from the electrode group is formed with a countersunk groove recessed radially outward, and the insulating layer includes a second insulating layer disposed in the countersunk groove.

[0010] Optionally, in the above-mentioned cover plates, along the thickness direction of the cover plate: The height of the second insulating layer is h3; The height of the second hole segment is H3; 0.3≤h3 / H3≤0.4, and / or, 0.35mm≤h3≤0.5mm.

[0011] Optionally, in the above-mentioned cover plate, Along the radial direction of the riveted portion, the thickness of the first insulating layer is 0.08mm-0.15mm; And / or, Along the radial direction of the second hole segment, the thickness of the second insulating layer is 0.08mm-0.15mm.

[0012] Optionally, in the above-mentioned cover plate, The first insulating layer is a first insulating coating; And / or, The second insulating layer is a second insulating coating.

[0013] Optionally, in the above-mentioned cover plate, the end side of the sleeve portion away from the pole group has a pre-riveting hole recessed towards the pole group, extending from the side away from the pole group to the side near the pole group, and the inner circumferential surface of the pre-riveting hole is inclined towards the central axis of the sleeve portion; 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°.

[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 electrode body and the riveting block are riveted together, on the side away from the electrode group, the riveting part of the sleeve part is riveted together with the second hole section of the sleeve hole, and the copper-aluminum riveting joint of the copper part and the second hole section of the aluminum part is exposed to the outside air. In this application, at least at the end away from the electrode group, an insulating layer is provided between the outer peripheral surface of the riveting part and the inner peripheral surface of the second hole section. In this way, on the end side away from the electrode group, the copper and aluminum at the riveting joint of the copper part and the second hole section of the aluminum part are insulated and isolated by the insulating layer. In this way, even if the copper-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 electrode 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. 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 A top view;

[0020] Figure 4 This is a cross-sectional view of the pole assembly of the cover plate before the pole body and the riveting block are riveted together in Structure 1 of this application.

[0021] Figure 5 This is a schematic diagram of the riveting block of Structure 1 of this application.

[0022] Figure 6 This is a cross-sectional view of the pole assembly of the cover plate after the pole body and the riveting block of Structure 1 of this application are riveted together.

[0023] Figure 7 This is a schematic diagram of the riveting block of structure two in this application.

[0024] Figure 8 for Figure 7 A cross-sectional view parallel to the front view.

[0025] Figure 9 This is a cross-sectional view of the pole assembly of the cover plate in Structure II of this application.

[0026] superior Figures 1-9 middle: 1. Cover plate body; 2. Terminal post assembly; 3. Terminal post body; 4. Riveting block; 5. Terminal post base plate; 6. Upper plastic; 7. Lower plastic; 31. Sleeve installation part; 32. First insulation layer 41. Sleeve hole; 42. Second insulating layer; 311. Riveting part; 312. Pre-riveting hole; 313. Mating part; 411. First hole section; 412. Second hole section; 413. Third hole section. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] like Figures 1-9 As shown, this application embodiment provides a cover plate for sealing the opening of a battery cell's casing; the electrode assembly is disposed within the internal space enclosed by the casing. 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 passes through the cover plate body 1, and the riveting block 4 is located on the side of the cover plate body 1 away from the electrode post assembly, and is fitted onto the portion of the electrode post body 3 that extends out of the cover plate body 1; the electrode post body 3 and the riveting block 4 each include a fitted portion 31 and a fitted hole 41 that are fitted together. Please refer to... Figures 5-6 , Figures 8-9 The sleeve hole 41 includes a first hole segment 411, a second hole segment 412, and a third hole segment 413 connected sequentially and with progressively smaller diameters from the side away from the electrode group to the side closer to the electrode group. At the end of the sleeve portion 31 away from the electrode group, a riveting portion 311 is formed that can be sleeved and riveted to the second hole segment 412. At least at the end away from the electrode group, an insulating layer is provided between the outer peripheral surface of the riveting portion 311 and the inner peripheral surface of the second hole segment 412.

[0030] 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 sleeve portion 31 away from the electrode group is the end face of the sleeve portion 31 away from the electrode group; the end point of the sleeve portion 31 away from the electrode group is the segment of the sleeve portion 31 extending from the end side away from the electrode group towards the end side closer to the electrode group. The understanding of end side and end point for other components is the same, and will not be elaborated here.

[0031] Please see Figure 4 , Figure 9 The cover plate includes an upper plastic 6 and a lower plastic 7. The upper plastic 6 is located on the end face of the cover plate body 1 away from the electrode assembly, and the upper plastic 6 forms an insulating space. The riveting block 4 is located in the insulating space. The lower plastic 7 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 5, which is connected to the end side of the electrode post body 3 near the electrode assembly. The electrode post base plate 5 is located on the side of the cover plate body 1 near the electrode assembly and abuts against the lower plastic 7. The electrode post body 3 passes through the sleeve hole 41 of the lower plastic 7, the cover plate body 1, the upper plastic 6, and the riveting block 4 in sequence. The electrode post body 3 and the electrode post base plate 5 are integrally connected structures.

[0032] Further explanation is needed, for example, please refer to [link / reference]. Figure 4 Before the pole body 3 is riveted to the riveting block 4, the outer diameter of the sleeve portion 31 is consistent with that of the inner diameter of the third hole section 413; optionally, the end of the sleeve portion 31 away from the pole assembly extends into the sleeve hole 41. Please refer to Figure 4 , Figure 5 When the pole body 3 is riveted to the riveting block 4, the end of the sleeve portion 31 away from the pole group is riveted towards the pole group using a riveting press. The end of the sleeve portion 31 away from the pole group will undergo axial compression deformation and radial expansion deformation, thereby riveting the material until it is riveted to the second hole section 412 for connection. The first hole section 411 is a riveting hole that limits the displacement of the riveting press; the second hole section 412 is a riveting hole for riveting connection with the pole body 3. Please refer to Figure 6 After the pole body 3 is riveted to the riveting block 4, the sleeve part 31 includes a mating part 313 that is sleeved with the third hole section 413, and a riveting part 311 that is sleeved and riveted with the second hole section 412.

[0033] 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.

[0034] After the pole body 3 is riveted to the riveting block 4, on the side away from the pole group, the riveting part 311 of the sleeve part 31 is riveted to the second hole section 412 of the sleeve hole 41, and the copper-aluminum riveting joint of the copper part 311 and the second hole section 412 of the aluminum material will be exposed to the outside air. In this application, at least at the end away from the pole group, an insulating layer is provided between the outer peripheral surface of the riveting part 311 and the inner peripheral surface of the second hole section 412. In this way, the copper and aluminum at the riveting joint of the copper part 311 and the second hole section 412 of the aluminum material will be insulated and isolated by the insulating layer. In this way, even if the copper-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 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.

[0035] Please see Figure 4 In some embodiments, the first insulating layer 32 is provided only on the outer peripheral surface of the end of the riveted portion 311 furthest from the pole group. See also... Figure 8 In some parallel embodiments, the second insulating layer 42 is provided only on the inner peripheral surface of the end of the second hole segment 412 away from the electrode group. In some parallel embodiments, the first insulating layer 32 is provided on both the outer peripheral surface of the end of the riveting portion 311 away from the electrode group and the inner peripheral surface of the second hole segment 412 away from the electrode group.

[0036] Structure 1 (see also) Figures 4-6 ) The sleeve portion 31 is provided with a first insulating layer 32 on the outer peripheral surface of the end of the riveting portion 311 away from the pole group, so as to achieve an insulating layer between the riveting portion 311 and the second hole section 412 at the end away from the pole group.

[0037] For details, please refer to Figure 4 , Figure 6 The insulating layer includes a first insulating layer 32. The outer peripheral surface of the end of the riveting portion 311 away from the pole group has a stepped area that is recessed radially inward, and the first insulating layer 32 is disposed in the stepped area.

[0038] It should be noted that the space formed by the step area is the recessed space where material is missing, formed by the step area being recessed radially inward along the riveting portion 311; the step area has a width along the radial direction of the riveting portion 311. The thickness of the first insulating layer 32 is equal to the width of the step area along the radial direction of the riveting portion 311. In some parallel embodiments, the thickness of the first insulating layer 32 can be greater than the width of the step area, or the thickness of the first insulating layer 32 can be less than the width of the step area; the setting of the thickness of the first insulating layer 32 can be flexibly selected according to the actual situation, as long as it ensures that after the pole body 3 and the riveting block 4 are riveted, the riveting portion 311 can be reliably riveted and fixed to the second hole section 412, and the first insulating layer 32 is located between the copper and aluminum at the riveting point of the riveting portion 311 and the second hole section 412.

[0039] It should be further noted that, along the thickness direction of the cover plate, the height of the first insulating layer 32 is the same as the height of the stepped area; along the thickness direction of the cover plate, i.e. Figure 4 The direction indicated by the middle arrow.

[0040] The stepped area provides space for the first insulating layer 32 and allows for the limitation of the thickness and height of the first insulating layer 32, making them level with the width and height of the stepped area, respectively. This ensures good insulation between the copper and aluminum at the riveting joint 311 and the second hole section 412, while also guaranteeing the best riveting and fixing effect between the riveting joint 311 and the second hole section 412, thus ensuring a high riveting yield.

[0041] Please see Figure 4 In some embodiments of this application, before the pole body 3 is riveted to the riveting block 4, along the thickness direction of the cover plate: the height of the first insulating layer 32 is h1; the height of the second hole section 412 from the end near the pole group to the end away from the pole group of the riveting part 311 is H1; 0.3≤h1 / H1≤0.45; for example, h1 / H1 can be any one of 0.3, 0.35, 0.4, 0.45, etc.

[0042] It should be noted that the height h1 of the first insulating layer 32 is the initial height of the first insulating layer 32. The "end side of the riveting portion 311 away from the electrode group" is level with the "end side of the first insulating layer 32 away from the electrode group". A first stepped surface is formed at the connection between the second hole segment 412 and the third hole segment 413; the "end side of the second hole segment 412 near the electrode group" is level with the "position of the first stepped surface". Before the pole body 3 and the riveting block 4 are riveted, the "height H1 from the end side of the second hole segment 412 near the electrode group to the end side of the riveting portion 311 away from the electrode group" is the first height, which is the "height of the riveting portion 311 extending from the first stepped surface in the direction away from the electrode group before riveting".

[0043] As mentioned above, before the pole body 3 and the riveting block 4 are riveted, the initial height and the first height of the first insulating layer 32 are limited to a reasonable range. This can prevent the initial height of the first insulating layer 32 from being too small, which would result in poor insulation between the copper and aluminum at the riveting point after riveting; and it can also prevent the initial height of the first insulating layer 32 from being too large, which would affect the strength of the riveting structure.

[0044] In some embodiments, 2.4mm ≤ H1 ≤ 2.8mm; for example, H1 can be any of 2.4mm, 2.6mm, 2.8mm, etc.

[0045] Thus, before the pole body 3 and the riveting block 4 are riveted, the first height of the riveting part 311 is limited to a reasonable range. This avoids the first height being too small, which would result in insufficient material for riveting expansion and affect the strength of the riveting structure. At the same time, it also avoids the first height being too large, which would result in uncontrolled riveting expansion and affect the riveting yield. By limiting the first height to a reasonable range, this application can effectively ensure the riveting expansion of the riveting part 311, thus guaranteeing the riveting yield and the strength of the riveting structure.

[0046] Please see Figure 6 In some embodiments of this application, after the pole body 3 and the riveting block 4 are riveted together, along the thickness direction of the cover plate: the end side of the first insulating layer 32 away from the pole group is flush with the end side of the second hole segment 412 away from the pole group, and the height of the first insulating layer 32 is h2; the height from the end side of the second hole segment 412 near the pole group to the end side of the riveting part 311 away from the pole group is H2. 0.35≤h2 / H2≤0.45; for example, h2 / H2 can be any one of 0.35, 0.4, 0.45, etc.

[0047] It should be noted that the height h2 of the first insulating layer 32 is the final height of the first insulating layer 32. After the pole body 3 is riveted to the riveting block 4, the height H2 of the second hole section 412 from the end near the pole group to the end of the riveting part 311 away from the pole group is the second height, which is "the height of the riveting part 311 extending from the first step towards the direction away from the pole group after riveting". Since riveting causes axial compression deformation and radial expansion deformation of the sleeve part 31, the height of the first insulating layer 32 will be compressed, that is, the initial height of the first insulating layer 32 is less than the final height.

[0048] As shown above, after the pole body 3 and the riveting block 4 are riveted together, the final height and the second height of the first insulating layer 32 are limited to a reasonable range. This avoids the final height of the first insulating layer 32 being too small, which would prevent the insulation between the copper and aluminum at the riveting point from being properly achieved. It also avoids the final height of the first insulating layer 32 being too large, which would affect the strength of the riveting structure.

[0049] In some embodiments, 0.9mm ≤ H2 ≤ 1.2mm; for example, H2 can be any one of 0.9mm, 1mm, 1.1mm, 1.2mm, etc.

[0050] Thus, after the pole body 3 and the riveting block 4 are riveted together, the second height of the riveting part 311 is limited to a reasonable range. This avoids the second height being too small, which would affect the strength of the riveting structure, while also avoiding the second height being too large, which would cause difficulties in riveting material expansion, increase the difficulty of riveting, and affect the riveting yield.

[0051] Furthermore, 0.35mm ≤ h2 ≤ 0.5mm; for example, h2 can be any of 0.35mm, 0.38mm, 0.5mm, etc.

[0052] In some embodiments of this application, the thickness of the first insulating layer 32 along the radial direction of the riveting portion 311 is t1, 0.08mm≤t1≤0.15mm; for example, t1 can be any one of 0.08mm, 0.1mm, 0.13mm, 0.15mm, etc.

[0053] It should be noted that the thickness t1 of the first insulating layer 32 is the thickness before the pole body 3 is riveted to the riveting block 4.

[0054] In this way, the thickness of the first insulating layer 32 is limited to a reasonable range, which can avoid the first insulating layer 32 being too thin, which would result in poor insulation between the copper and aluminum at the riveting joint; and also avoid the first insulating layer 32 being too thick, which would affect the strength of the riveting structure.

[0055] In some embodiments of this application, the first insulating layer 32 is a first insulating coating.

[0056] It should be noted that the first insulating coating can be obtained by electrostatic spraying of solid epoxy insulating material powder, electrostatic spraying of nano-modified resin, or spraying of polyester coating, etc.

[0057] Before the pole body 3 and the riveting block 4 are riveted together, a first insulating coating is sprayed on the stepped area of ​​the riveting part 311 by a spraying process. This not only has a simple structure and is easy to process, but also can well ensure the insulation effect between copper and aluminum at the riveting point after riveting.

[0058] To ensure that the cover plate of Structure 1 can effectively achieve the functions and effects described above after being assembled onto the battery cell, the dimensions of the first insulating layer 32, the riveting part 311, etc., must be within the parameter range specified above. Table 1 shows experimental data for some embodiments and comparative examples. Wherein: t1: The thickness of the first insulating layer 32 along the radial direction of the riveting part 311 before the pole body 3 is riveted to the riveting block 4; h1: The height of the first insulating layer 32 along the thickness direction of the cover plate before the pole body 3 is riveted to the riveting block 4. H1: Before the pole body 3 is riveted to the riveting block 4, the height of the second hole section 412 from the end side of the pole group to the end side of the riveting part 311 away from the pole group along the thickness direction of the cover plate. h2: The height of the first insulating layer 32 along the thickness direction of the cover plate after the pole body 3 is riveted to the riveting block 4; H2: After the pole body 3 is riveted to the riveting block 4, the height of the second hole section 412 from the end side near the pole group to the end side away from the pole group along the thickness direction of the cover plate.

[0059] Table 1 As can be seen from Table 1, the dimensions of the first insulating layer 32, the riveting part 311, etc. of the cover plate of Structure 1 can only guarantee the anti-corrosion effect of the cover plate when they meet the parameter range defined in the above embodiment.

[0060] Structure 2 (see also) Figures 7-9 ) The sleeve hole 41 is provided with a second insulating layer 42 at least on the inner peripheral surface of the end of the second hole segment 412 away from the pole group, so as to achieve an insulating layer between the outer peripheral surface of the riveting part 311 and the inner peripheral surface of the second hole segment 412 at the end away from the pole group.

[0061] For details, please refer to Figures 7-9 The inner circumferential surface of the end of the second hole segment 412 away from the electrode group is formed with a recessed groove that is recessed outward along its radial direction, and the second insulating layer 42 is disposed in the recessed groove.

[0062] It should be noted that the space formed by the countersunk groove is the recessed space where material is missing, formed by the countersunk groove recessing radially outward along the second hole segment 412; the countersunk groove has a width along the radial direction of the second hole segment 412. The thickness of the second insulating layer 42 is equal to the width of the countersunk groove along the radial direction of the second hole segment 412. In some parallel embodiments, the thickness of the second insulating layer 42 can be greater than the width of the countersunk groove, or the thickness of the second insulating layer 42 can be less than the width of the countersunk groove; the setting of the thickness of the second insulating layer 42 can be flexibly selected according to the actual situation, as long as it ensures that after the pole body 3 and the riveting block 4 are riveted, the riveting part 311 can be reliably riveted and fixed to the second hole segment 412, and the second insulating layer 42 is located between the copper and aluminum at the riveting point of the riveting part 311 and the second hole segment 412.

[0063] It should be further noted that, along the thickness direction of the cover plate, the height of the second insulating layer 42 is the same as the height of the countersunk groove.

[0064] The countersunk groove provides space for the second insulating layer 42 and allows for the limitation of the thickness and height of the second insulating layer 42, making them level with the width and height of the countersunk groove, respectively. This ensures good insulation between the copper and aluminum at the riveting joint 311 and the second hole section 412, while also guaranteeing the best riveting and fixing effect between the riveting joint 311 and the second hole section 412, thus ensuring a high riveting yield.

[0065] Please see Figure 8 In some embodiments of this application, the end of the second insulating layer 42 away from the electrode group is flush with the end of the second hole segment 412 away from the electrode group, and the height of the second insulating layer 42 is h3; the height of the second hole segment 412 is H3; 0.3≤h3 / H3≤0.4; for example, h3 / H3 can be any one of 0.3, 0.35, 0.4, etc.

[0066] As shown above, the height of the second insulating layer 42 and the height of the second hole segment 412 are limited to a reasonable range. This avoids the second insulating layer 42 being too small in proportion to the height, which would prevent the insulation between the copper and aluminum at the riveting point from being properly achieved after riveting. It also avoids the second insulating layer 42 being too large in proportion to the height, which would affect the strength of the riveting structure.

[0067] In some embodiments, 0.35mm ≤ h3 ≤ 0.5mm; optionally, h3 can be any one of 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc.

[0068] In this way, the height of the second insulating layer 42 is limited to a reasonable range, which can avoid the second insulating layer 42 being too small, which would result in poor insulation between the copper and aluminum at the riveting point after riveting; and also avoid the second insulating layer 42 being too large, which would affect the strength of the riveting structure.

[0069] In some embodiments of this application, the thickness of the second insulating layer 42 along the radial direction of the second hole segment 412 is t2, 0.08mm≤t2≤0.15mm; for example, t2 can be any one of 0.08mm, 0.1mm, 0.13mm, 0.15mm, etc.

[0070] In this way, the thickness of the second insulating layer 42 is limited to a reasonable range, which can avoid the second insulating layer 42 being too thin, which would result in poor insulation between the copper and aluminum at the riveting joint; and also avoid the second insulating layer 42 being too thick, which would affect the strength of the riveting structure.

[0071] In some embodiments of this application, the second insulating layer 42 is a second insulating coating.

[0072] It should be noted that the second insulating coating can be obtained by electrostatic spraying of solid epoxy insulating material powder, electrostatic spraying of nano-modified resin, or spraying of polyester coating, etc.

[0073] Before the pole body 3 and the riveting block 4 are riveted, a second insulating coating is obtained by spraying the countersunk groove of the second hole section 412 through a spraying process. This not only has a simple structure and is easy to process, but also can well ensure the insulation effect between copper and aluminum at the riveting point after riveting.

[0074] To ensure that the cover plate of Structure Two can effectively achieve the functions and effects described above after being assembled onto the battery cell, the dimensions of the second insulating layer 42 and the second hole segment 412 must be within the parameter range specified above. Table 2 shows experimental data for some embodiments and comparative examples. Among them: t2: The thickness of the second insulating layer 42 along the radial direction of the second hole segment 412; h3: The height of the second insulating layer 42 along the thickness direction of the cover plate; H3: The height of the second hole section 412 along the thickness direction of the cover plate.

[0075] Table 2 As can be seen from Table 2, the dimensions of the second insulating layer 42 and the second hole segment 412 of the cover plate of Structure 2 can only guarantee the anti-corrosion effect of the cover plate when they meet the parameter range defined in the above embodiment.

[0076] Please see Figures 1-3 In some embodiments of this application, a pre-riveting hole 312 is formed on the end side of the sleeve portion 31 away from the electrode group (i.e., the end side of the riveting portion 311 away from the electrode group), which is recessed toward the electrode group. From the side away from the electrode group to the side closer to the electrode group, the inner peripheral surface of the pre-riveting hole 312 is inclined toward the direction close to the central axis of the sleeve portion 31.

[0077] When the cover plate is placed above the pole group, the pre-riveting hole 312 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 312 and riveted downward, the circumferential wall of the pre-riveting hole 312 can undergo better radial deformation, which facilitates the riveting part 311 to be riveted and expanded to be riveted and fixed with the second hole section 412 of the riveting block 4, thereby improving the riveting yield.

[0078] Please see Figure 2 In some embodiments, the depth of the pre-riveting hole 312 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.

[0079] As mentioned above, limiting the depth of the pre-riveting hole 312 to a reasonable range not only avoids the radial riveting expansion of the riveting part 311 due to the excessive depth of the pre-riveting hole 312, 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 312, thus affecting the riveting strength between the pole body 3 and the riveting block 4, and consequently affecting the reliability of the cover plate.

[0080] Please see Figure 3 In some embodiments, the wall thickness of the end of the pre-riveting hole 312 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.

[0081] The wall thickness of the end of the pre-riveting hole 312 furthest from the pole group is the minimum wall thickness of the pre-riveting hole 312, corresponding to the largest diameter portion of the tapered pre-riveting hole 312. The surrounding wall of the pre-riveting hole 312, at least at the end furthest from the pole group, is formed of the solid material of the riveting part 311.

[0082] As mentioned above, limiting the minimum wall thickness of the pre-riveting hole 312 to a reasonable range not only avoids the phenomenon of damage to the riveting part 311 during the riveting process due to the minimum wall thickness of the pre-riveting hole 312 being too small, thus causing riveting failure and generating scrap; but also avoids the minimum wall thickness of the pre-riveting hole 312 being too large, which would result in a small radial deformation of the riveting part 311, thereby affecting the riveting material expansion effect and the riveting yield.

[0083] Please see Figure 2 In some embodiments, the inclination angle of the inner circumferential surface of the pre-riveting hole 312 is γ, 10°≤γ≤25°; for example, γ can be any one of 10°, 20°, 25°, etc.

[0084] As mentioned above, limiting the inclination angle (i.e., taper) of the pre-riveting hole 312 to a reasonable range not only avoids excessive axial deformation of the riveting part 311 due to an excessively small inclination angle, but also avoids excessive radial deformation of the riveting part 311 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 312 to 10°–25° can control the axial and radial deformation of the riveting part 311 to a suitable range, thereby improving the riveting firmness.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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 respectively include a sleeve portion and a sleeve hole that are nested together; the sleeve hole includes a first hole segment, a second hole segment and a third hole segment that are connected in sequence and whose diameters decrease in sequence from the side away from the pole group to the side closer to the pole group; the end of the sleeve portion away from the pole group forms a riveting portion that can be nested and riveted with the second hole segment. At least at the end furthest from the pole group, an insulating layer is provided between the outer peripheral surface of the riveting portion and the inner peripheral surface of the second hole segment.

2. The cover plate according to claim 1, characterized in that, The outer peripheral surface of the end of the riveted portion away from the pole group has a stepped area that is recessed radially inward, and the insulating layer includes a first insulating layer disposed in the stepped area.

3. The cover plate according to claim 2, characterized in that, Before the pole body is riveted to the riveting block, along the thickness direction of the cover plate: The height of the first insulating layer is h1; The height of the second hole section from the end near the pole group to the end of the riveting part away from the pole group is H1; 0.3≤h1 / H1≤0.45, and / or, 2.4mm≤H1≤2.8mm.

4. The cover plate according to claim 2, characterized in that, After the pole body is riveted to the riveting block, along the thickness direction of the cover plate: The height of the first insulating layer is h2; The height of the second hole section from the end near the pole group to the end of the riveting part away from the pole group is H2; 0.35≤h2 / H2≤0.45, and / or, 0.9mm≤H2≤1.2mm.

5. The cover plate according to claim 1, characterized in that, The inner circumferential surface of the second hole segment away from the end of the electrode group is formed with a countersunk groove that is recessed radially outward, and the insulating layer includes a second insulating layer disposed in the countersunk groove.

6. The cover plate according to claim 5, characterized in that, Along the thickness direction of the cover plate: The height of the second insulating layer is h3; The height of the second hole segment is H3; 0.3≤h3 / H3≤0.4, and / or, 0.35mm≤h3≤0.5mm.

7. The cover plate according to any one of claims 1-6, characterized in that, Along the radial direction of the riveted portion, the thickness of the first insulating layer is 0.08mm-0.15mm; And / or, Along the radial direction of the second hole segment, the thickness of the second insulating layer is 0.08mm-0.15mm.

8. The cover plate according to any one of claims 1-6, characterized in that, The first insulating layer is a first insulating coating; And / or, The second insulating layer is a second insulating coating.

9. The cover plate according to claim 1, characterized in that, The sleeve portion has a pre-riveting hole recessed towards the pole group on the end side away from the pole group, extending from the side away from the pole group to the side closer to the pole group. The inner circumferential surface of the pre-riveting hole is inclined towards the central axis of the sleeve portion; 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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