Cover plate assembly and battery cell

Abstract

This invention relates to the field of battery technology, disclosing a cover plate assembly and a battery cell. The cover plate assembly includes: a cover plate body with an electrode post hole; an electrode post, comprising a plate and a post, the plate being located on one side of the cover plate body, the post comprising a rod and a head, the rod being connected between the plate and the head, at least a portion of the rod passing through the electrode post hole, and an annular flange being provided on the outer circumferential surface of the rod, the flange surrounding the rod circumferentially and spaced apart from the plate; and a sealing ring, fitted on the outer circumferential side of the rod, and along the height direction, the sealing ring being located between the flange and the plate, the sealing ring comprising a first ring and a second ring, the first ring being connected to the side of the second ring away from the plate, at least a portion of the first ring passing through the electrode post hole, the width of the first ring being less than or equal to the width of the flange. The flange protects the first ring, preventing it from hitting the cover plate body and being scraped and flipped, thus ensuring the sealing performance of the sealing ring.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to cover plate assemblies and battery cells. Background Technology

[0002] The cover plate assembly consists of a cover plate body, poles, riveting blocks, upper plastic parts, lower plastic parts, and sealing rings. The poles pass through pole holes in the cover plate body, and the sealing rings are fitted onto the poles to ensure a tight seal between the poles and the cover plate body. Currently, the assembly method for cover plate assemblies typically involves first fitting the sealing ring onto the pole's shaft, then passing the pole and sealing ring together through the through holes in the lower plastic parts, the cover plate body, the upper plastic parts, and the riveting blocks, and finally riveting to complete the assembly.

[0003] However, due to the positioning deviation between the pole and the cover plate body, the sealing ring is easily scraped by the cover plate body during the assembly process, causing it to turn upside down. The extrusion and turning upside down by the cover plate body will damage the sealing ring, resulting in sealing failure and poor sealing of the cover plate assembly. Summary of the Invention

[0004] In view of this, the present invention provides a cover plate assembly and a battery cell to solve the problem that the sealing ring is easily scraped and flipped by the cover plate body during the assembly of the cover plate assembly.

[0005] In a first aspect, the present invention provides a cover plate assembly, comprising: a cover plate body having an electrode post hole; an electrode post including a plate and a post, the plate being located on one side of the cover plate body, the post including a rod and a head, the rod being connected between the plate and the head, at least a portion of the rod passing through the electrode post hole, an annular flange being provided on the outer circumferential surface of the rod, the flange being arranged around the rod in the circumferential direction and spaced apart from the plate; and a sealing ring fitted on the outer circumferential side of the rod, and along the height direction, the sealing ring being located between the flange and the plate, the sealing ring including a first ring and a second ring, the first ring being connected to the side of the second ring opposite to the plate, at least a portion of the first ring passing through the electrode post hole, the width of the first ring being less than or equal to the width of the flange.

[0006] Beneficial effects: By providing an annular protrusion around the rod portion of the pole, with the protrusion spaced apart from the plate body along the height direction, a sealing ring can be placed between the protrusion and the plate body, limiting the sealing ring along the height direction. Simultaneously, by ensuring that the width of the first ring of the sealing ring is less than or equal to the width of the protrusion, the outer contour of the first ring will not protrude beyond the outer contour of the protrusion. Therefore, during the insertion of the pole and sealing ring into the pole hole, the protrusion protects the first ring, preventing the end of the first ring away from the second ring from touching the cover plate body and being scratched. This prevents the top of the sealing ring from turning up, protecting the sealing ring from being squeezed and damaged by the cover plate body, thus ensuring the sealing performance of the sealing ring and improving the reliability of the cover plate assembly.

[0007] In one alternative embodiment, along the height direction, the distance between the convex edge and the plate is equal to the height of the sealing ring, and the side of the convex edge facing away from the plate is flush with the side of the rod facing away from the plate.

[0008] Beneficial effects: By setting the distance between the flange and the plate to be equal to the height of the sealing ring, the sealing ring is precisely embedded in the space between the flange and the plate, thus limiting the sealing ring along the height direction and improving the stability of the sealing ring. Furthermore, by setting the side of the flange away from the plate to be flush with the side of the rod away from the plate, i.e., the flange is located at the top of the rod, the distance between the flange and the plate can be maximized, which facilitates the processing and forming of the pole post. In addition, in the cover plate assembly, both the flange and the rod abut against the riveting block, which helps to improve the stability of the overall structure.

[0009] In one optional embodiment, the cover plate assembly further includes a first plastic part disposed on the side of the cover plate body facing the plate body. The first plastic part includes at least a first portion sandwiched between the cover plate body and the plate body. The first portion has a dimension h1 along the height direction; the cover plate body has a dimension h2 along the height direction; the distance between the protruding edge and the plate body along the height direction is h3; and the rod portion has a dimension h0 along the height direction. The relationships h1, h2, h3, and h0 satisfy the following formula: h1 + h2 < h3 < h0.

[0010] Beneficial effects: By limiting h3 to be greater than h1+h2, the total height of the sealing ring is greater than the sum of the dimensions of the first part and the cover plate body along the height direction. The upper surface of the sealing ring is higher than the upper surface of the cover plate body. Even if external liquid enters the area between the sealing ring and the electrode hole, the liquid can be prevented from contacting the electrode by the blocking effect of the sealing ring. This prevents the electrode and the cover plate body from conducting after the external liquid enters the area between the sealing ring and the electrode hole, thus avoiding poor cell performance. At the same time, by limiting h3 to be less than h0, it can be ensured that the rod part has space to set the protrusion along the height direction, thereby ensuring the protective effect of the protrusion on the sealing ring during the assembly process of the cover plate assembly, and ensuring the sealing performance of the sealing ring.

[0011] In one alternative implementation, h1, h2, h3, and h0 satisfy the following relationship: 0.05 ≤ [h3 - (h1 + h2)] / h0 ≤ 0.15.

[0012] Beneficial effects: By limiting the value of [h3-(h1+h2)] / h0 to the range of 0.05 to 0.15, it can ensure that the sealing ring has sufficient size in the height direction, effectively preventing external liquid from entering the area between the sealing ring and the electrode post hole and causing the electrode post and the cover plate body to conduct, thus avoiding poor cell performance. It can also ensure that the flange has sufficient size in the height direction, thereby ensuring the structural strength of the flange and providing effective protection for the sealing ring during the assembly of the cover plate assembly, thus ensuring that the sealing ring is not damaged and ensuring the sealing performance of the sealing ring and the reliability of the cover plate assembly.

[0013] In one optional implementation, the value of h1 is in the range of: 0.5 mm ≤ h1 ≤ 1.5 mm;

[0014] And / or, the range of h2 is: 1.5 mm ≤ h2 ≤ 3 mm;

[0015] And / or, the range of h3 is: 2 mm ≤ h3 ≤ 5 mm;

[0016] And / or, the range of h0 is: 3 mm ≤ h0 ≤ 6 mm.

[0017] Beneficial effects: By limiting h1 to a value within the range of 0.5 mm to 1.5 mm, it can ensure that the first plastic part can provide sufficient insulation between the plate and the cover plate body, preventing the cover plate body from conducting with the electrode post. It can also prevent the first plastic part from being too thick, which would lead to severe shrinkage and deformation, thus ensuring the reliability of the cover plate assembly. Furthermore, it can prevent the overall weight and volume of the cover plate assembly from being too large, which is beneficial to improving the volumetric energy density of the battery cell.

[0018] And / or, by limiting h2 to a value between 1.5 mm and 3 mm, it is possible to ensure that the cover plate body has sufficient structural strength, avoid deformation of the cover plate body, ensure that its flatness meets the requirements, control the weight and cost of the cover plate body, avoid the cover plate body occupying too much space along the height direction, and improve the volumetric energy density of the battery cell.

[0019] And / or, by limiting h3 to a value between 2 mm and 5 mm, it is possible to ensure that the cover plate assembly has good insulation, strength and other properties, while avoiding the cover plate assembly being too large, which facilitates the overall structure layout of the battery cell.

[0020] And / or, by limiting h0 to a value between 3 mm and 6 mm, it can be ensured that the rod can provide sufficient installation space for the sealing ring along the height direction, thereby ensuring the sealing performance of the cover assembly. At the same time, it can also avoid the rod being too large along the height direction, which would cause the cover assembly to be too large along the height direction, thereby avoiding excessive occupation of cell space and improving the volumetric energy density of the cell.

[0021] In one optional embodiment, the rod is racetrack-shaped or cylindrical, and the orthographic projection of the rod on the plate along the height direction includes at least two semicircular areas arranged opposite each other along the length direction. The radius of the semicircular area is r, and the ring width of the convex edge is a, wherein a and r satisfy the relationship: 0.1≤a / r≤0.2.

[0022] Beneficial effects: By limiting the value of a / r to between 0.1 and 0.2, it can be ensured that the flange can be smoothly processed and formed, and can provide effective protection for the sealing ring during the assembly of the cover plate assembly, avoiding damage to the sealing ring by the cover plate body. It can also avoid the flange being too wide, which would result in the cross-sectional area of ​​the rod being too small, thus ensuring that the pole has good structural strength and current carrying capacity.

[0023] In one optional implementation, the value of a ranges from 0.3 mm to a ≤ 2.5 mm.

[0024] Beneficial effects: By limiting the value of 'a' to the range of 0.3 mm to 2.5 mm, it is possible to ensure that the protruding edge can be smoothly processed and formed, and to provide effective protection for the sealing ring during the assembly of the cover plate assembly, preventing the sealing ring from being scraped and flipped by the cover plate body, thereby ensuring the sealing performance of the cover plate assembly. It is also possible to avoid the protruding edge being too wide, which would result in the cross-sectional area of ​​the rod being too small, thereby ensuring that the pole has good structural strength and current carrying capacity, avoiding excessively high charging and discharging temperatures of the battery cell, and improving the safety of the battery cell.

[0025] In one optional implementation, the value of r is in the range of 2 mm ≤ r ≤ 20 mm.

[0026] Beneficial effect: By limiting r to a value between 2 mm and 20 mm, it can be ensured that the cross-section of the pole has reasonable dimensions, thus ensuring that the pole can be successfully riveted.

[0027] In one alternative embodiment, the ring width of the first ring portion is equal to the ring width of the convex edge.

[0028] Beneficial effects: By setting the ring width of the first ring to be equal to the ring width of the protruding edge, on the one hand, it ensures that the first ring will not protrude beyond the outer circumference of the protruding edge, thus ensuring the protective effect of the protruding edge on the first ring. On the other hand, it can also maximize the ring width of the first ring, thereby avoiding an excessive gap between the first ring and the hole wall of the pole post, and ensuring the sealing performance of the sealing ring.

[0029] Secondly, the present invention also provides a battery cell, comprising: a housing having an open end; an electrode assembly disposed within the housing; and the aforementioned cover plate assembly, the cover plate assembly covering the open end of the housing. Since the battery cell includes the cover plate assembly and has the same effect as the cover plate assembly, it will not be described in detail here. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a top view of a cover plate assembly according to an embodiment of the present invention;

[0032] Figure 2 for Figure 1 A cross-sectional view along the AA direction;

[0033] Figure 3 for Figure 1 An exploded view of the cover plate assembly shown;

[0034] Figure 4 This is a schematic diagram of the structure of a pole post according to an embodiment of the present invention;

[0035] Figure 5 for Figure 4 A top view of the pole shown;

[0036] Figure 6 for Figure 5 Cross-sectional view along the BB direction;

[0037] Figure 7 for Figure 4The front view of the pole shown;

[0038] Figure 8 for Figure 7 A cross-sectional view along the CC direction;

[0039] Figure 9 This is a schematic diagram of the structure of a sealing ring according to an embodiment of the present invention;

[0040] Figure 10 for Figure 9 The cross-sectional view of the sealing ring shown.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Cover plate body; 101. Pole post hole; 2. Pole post; 210. Plate body; 220. Column body; 221. Rod part; 2211. Semicircular area; 2212. Rectangular area; 222. Raised edge; 223. Head; 3. Sealing ring; 301. First ring part; 302. Second ring part; 4. First plastic part; 401. First section; 402. First through hole; 5. Riveting block; 501. Riveting hole; 6. Second plastic part; 601. Second through hole; 7. Explosion-proof valve; 8. Explosion-proof patch. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Lithium-ion batteries are a type of battery. With the increasing maturity of lithium-ion battery technology, they are widely used as power batteries in electric vehicles and energy storage. The performance and safety requirements for lithium-ion batteries are also rising. The cover assembly is a key component of a lithium-ion battery, its functions including welding with the casing to form a sealed cavity, leading out the positive and negative electrodes, and serving as an assembly carrier. The cover assembly consists of a cover body, terminals, riveting blocks, upper plastic, lower plastic, and a sealing ring. Currently, the assembly method typically involves first fitting the sealing ring onto the terminal post, then passing the terminal post and sealing ring together through the through holes in the lower plastic, cover body, upper plastic, and riveting blocks, and finally riveting to complete the assembly. However, due to positioning deviations between the terminals and the cover body, the end of the sealing ring facing away from the terminal post is easily scraped by the cover body during assembly, causing it to fold over. This folding over by the cover body can damage the sealing ring, leading to seal failure and poor sealing of the cover assembly.

[0045] The following is combined with Figures 1 to 10 The following describes embodiments of the present invention.

[0046] According to embodiments of the present invention, in one aspect, a cover plate assembly is provided, such as... Figures 1 to 10 As shown, the cover plate assembly includes: a cover plate body 1, a pole post 2, and a sealing ring 3. The cover plate body 1 has a pole post hole 101; the pole post 2 includes a plate body 210 and a post body 220. The plate body 210 is located on one side of the cover plate body 1. The post body 220 includes a rod portion 221 and a head 223. The rod portion 221 connects the plate body 210 and the head 223. At least a portion of the rod portion 221 passes through the pole post hole 101. An annular flange 222 is provided on the outer circumferential surface of the rod portion 221, and the flange 222 surrounds the rod portion 221 circumferentially. The flange 222 is spaced apart from the plate 210; the sealing ring 3 is sleeved on the outer periphery of the rod 221, and along the height direction, the sealing ring 3 is located between the flange 222 and the plate 210. The sealing ring 3 includes a first ring portion 301 and a second ring portion 302. The first ring portion 301 is connected to the side of the second ring portion 302 away from the plate 210. At least a portion of the first ring portion 301 passes through the pole hole 101. The ring width of the first ring portion 301 is less than or equal to the ring width of the flange 222.

[0047] Among them, the height direction refers to Figure 2 and Figure 6 , Figure 7 The arrow points to the "height direction"; the rod 221 has a first centerline extending along the height direction; the outer circumferential surface of the rod 221 refers to the circumferential surface of the rod 221 on the side facing away from the first centerline in a direction perpendicular to the first centerline; the raised edge 222 is formed by a portion of the outer circumferential surface of the rod 221 protruding in a direction perpendicular to and away from the first centerline; the ring width of the raised edge 222 refers to the width dimension of the raised edge 222 on one side in the height direction; the first ring 301 is annular and surrounds the outer circumference of the rod 221; the ring width of the first ring 301 refers to the width dimension of the first ring 301 on one side in the height direction; the dividing line between the first ring 301 and the second ring 302 is as follows: Figure 10 As shown by the dotted lines, the center line of the first ring portion 301 and the center line of the second ring portion 302 are collinear, and the inner wall of the second ring portion 302 is located on the extension surface of the inner wall of the first ring portion 301 along the height direction. The inner walls of the first ring portion 301 and the inner walls of the second ring portion 302 are both attached to the outer peripheral surface of the rod portion 221. It should be noted that the dotted lines are only for illustration and do not actually exist. In fact, the first ring portion 301 and the second ring portion 302 of the sealing ring 3 are integrally formed.

[0048] By applying the cover plate assembly of this embodiment, an annular protrusion 222 is provided around the rod portion 221 of the pole post 2, and the protrusion 222 is spaced apart from the plate body 210 along the height direction. The sealing ring 3 can be placed between the protrusion 222 and the plate body 210. The protrusion 222 limits the sealing ring 3 along the height direction. At the same time, by setting the ring width of the first ring portion 301 of the sealing ring 3 to be less than or equal to the ring width of the protrusion 222, the outer contour of the first ring portion 301 will not protrude from the outer contour of the protrusion 222. Thus, during the process of the pole post 2 and the sealing ring 3 being inserted into the pole post hole 101, the protrusion 222 protects the first ring portion 301, preventing the end of the first ring portion 301 away from the second ring portion 302 from touching the cover plate body 1 and being scratched. This prevents the top of the sealing ring 3 from turning over, protects the sealing ring 3 from being squeezed and damaged by the cover plate body 1, and ensures the sealing performance of the sealing ring 3, thereby improving the reliability of the cover plate assembly.

[0049] It should be noted that during the assembly of the cover plate assembly, the sealing ring 3 is first fitted onto the rod 221. The post 220 and the sealing ring 3 pass through the pole hole 101 on the cover plate body 1 together. The top of the sealing ring 3 reaches the cover plate body 1 first. Without the protection of the raised edge 222, due to the positioning deviation between the pole 2 and the pole hole 101, the top of the sealing ring 3 is prone to scraping against the cover plate body 1 around the pole hole 101 and turning over. In this embodiment, an annular raised edge 222 is added to the pole 2. During the assembly process, the raised edge 222 can protect the top of the sealing ring 3 from contacting the cover plate body 1, thereby avoiding scraping. Here, the top of the sealing ring 3 refers to the end of the sealing ring 3 that is away from the plate body 210 along the height direction.

[0050] Further integration Figure 6 As shown, the dividing line between the rod portion 221, the head 223, and the flange 222 of the pole post 2 is as follows: Figure 6 As shown by the dotted lines, it should be noted that the dotted lines are for illustrative purposes only; in reality, the pole post 2 is a single-piece structure. The head 223 is riveted to the riveting block 5. Before riveting, the head 223 is rod-shaped, and the cross-section of the head 223 is smaller than the cross-section of the rod portion 221. After riveting, the head 223 forms a shape similar to... Figure 2 The two column segments with unequal cross-sections shown are used to achieve a fixed connection with the riveting block 5.

[0051] In one embodiment, the width of the first ring portion 301 is equal to the width of the protruding edge 222. It should be noted that before the sealing ring 3 is compressed, the width of the first ring portion 301 is equal to the width of the protruding edge 222. By setting the width of the first ring portion 301 to be equal to the width of the protruding edge 222, it ensures that the first ring portion 301 does not protrude beyond the outer periphery of the protruding edge 222, thus guaranteeing the protective effect of the protruding edge 222 on the first ring portion 301. Furthermore, it maximizes the width of the first ring portion 301, thereby preventing excessive gaps between the first ring portion 301 and the wall of the pole hole 101, ensuring the sealing performance of the sealing ring 3.

[0052] In other embodiments, the ring width of the first ring portion 301 can also be smaller than the ring width of the protruding edge 222, which can also ensure the protective effect of the protruding edge 222 on the first ring portion 301. It is necessary to ensure that there is no large gap between the sealing ring 3 and the inner wall of the pole hole 101 after compression, so as to ensure the sealing performance.

[0053] In one embodiment, further combination Figure 2 As shown, along the height direction, the distance between the raised edge 222 and the plate 210 is equal to the height of the sealing ring 3. The side of the raised edge 222 facing away from the plate 210 is flush with the side of the rod 221 facing away from the plate 210. It should be noted that the height of the sealing ring 3 refers to the total dimension of the sealing ring 3 along the height direction, that is, the total dimension of the first ring 301 and the second ring 302 along the height direction. The total height of the sealing ring 3 remains unchanged before and after it is compressed (that is, before and after the sealing ring 3 is assembled with the pole post 2 and the cover plate body 1), and is always equal to the distance between the raised edge 222 and the plate 210. The second ring 302 of the sealing ring 3 is compressed to ensure the sealing between the pole post 2 and the cover plate body 1. The distance between the raised edge 222 and the plate 210 refers to the vertical distance between the surface of the raised edge 222 facing the plate 210 and the surface of the plate 210 facing the raised edge 222.

[0054] Specifically, by setting the distance between the protruding edge 222 and the plate 210 to be equal to the height of the sealing ring 3, the sealing ring 3 is precisely embedded in the space between the protruding edge 222 and the plate 210, thereby limiting the sealing ring 3 along the height direction and improving the stability of the sealing ring 3. Furthermore, by setting the side of the protruding edge 222 away from the plate 210 to be flush with the side of the rod 221 away from the plate 210, that is, the protruding edge 222 is located at the top of the rod 221, the distance between the protruding edge 222 and the plate 210 can be maximized, and it is also convenient for the pole post 2 to be processed and formed. In addition, in the cover plate assembly, both the protruding edge 222 and the rod 221 abut against the riveting block 5, which is beneficial to improving the stability of the overall structure.

[0055] In one embodiment, further combination Figure 2As shown, the cover plate assembly also includes a first plastic part 4, which is disposed on the side of the cover plate body 1 facing the plate 210. The first plastic part 4 includes at least a first portion 401 sandwiched between the cover plate body 1 and the plate 210. The first portion 401 has a dimension of h1 along the height direction; the cover plate body 1 has a dimension of h2 along the height direction; the distance between the protruding edge 222 and the plate 210 along the height direction is h3; and the rod portion 221 has a dimension of h0 along the height direction. The relationship between h1, h2, h3, and h0 is: h1 + h2 < h3 < h0. It should be noted that the first portion 401 is located between the plate 210 and the cover plate body 1, and is used to ensure the insulation between the plate 210 and the cover plate body 1. The dimension h1 of the first portion 401 along the height direction is equal to the distance between the plate 210 and the cover plate body 1. The pole hole 101 includes a first hole section and a second hole section. The second hole section is connected to the side of the first hole section away from the plate 210. The diameter of the second hole section is larger than the diameter of the first hole section. The second hole section forms a countersunk platform on the cover plate body 1. The second plastic part 6 is disposed between the cover plate body 1 and the riveted... Between the connecting blocks 5, insulation between the cover plate body 1 and the riveting block 5 is ensured. The second plastic part 6 is provided with a convex ring on the side away from the riveting block 5 along the height direction. The second hole section cooperates with the convex ring to realize the positioning between the second plastic part 6 and the cover plate body 1. h2 refers to the dimension along the height direction of the area on the cover plate body 1 where the countersunk platform is not provided, which is equal to the sum of the dimensions along the height direction of the first hole section and the second hole section. h3 is the vertical distance between the surface of the convex edge 222 facing the plate body 210 and the surface of the plate body 210 facing the convex edge 222.

[0056] It should be noted that the lower surface of the sealing ring 3 abuts against the upper surface of the plate 210, and the lower surface of the first portion 401 abuts against the upper surface of the plate 210. h1 + h2 is equal to the distance along the height direction between the lower surface of the first portion 401 and the upper surface of the cover plate body 1. By limiting h3 to be greater than h1 + h2, the total height of the sealing ring 3 is greater than the sum of the dimensions of the first portion 401 and the cover plate body 1 along the height direction. The upper surface of the sealing ring 3 is higher than the upper surface of the cover plate body 1. Even if external liquid enters the sealing ring 3, the sealing ring 3 will be able to withstand the impact of external liquid. The area between the terminal hole 101 can also prevent liquid from contacting the terminal 2 under the blocking effect of the sealing ring 3. This prevents external liquid from entering the area between the sealing ring 3 and the terminal hole 101 and causing the terminal 2 and the cover plate body 1 to become conductive, thus avoiding poor cell performance. At the same time, by limiting h3 to be less than h0, it can be ensured that the rod 221 has space for setting the protrusion 222 in the height direction, thereby ensuring the protective effect of the protrusion 222 on the sealing ring 3 during the assembly of the cover plate assembly, and ensuring the sealing performance of the sealing ring 3. Here, the lower surface refers to Figure 2 The surface indicated by the middle arrow pointing "down" refers to the upper surface. Figure 2 The surface in the direction indicated by the middle arrow, which points to "up".

[0057] Further integration Figures 2 to 3 As shown, the first plastic part 4 has a first through hole 402 corresponding to the pole hole 101. The first portion 401 is arranged around the circumferential edge of the first through hole 402. The first through hole 402 allows a portion of the rod portion 221 near the plate 210 and the second ring portion 302 of the sealing ring 3 to pass through. The first plastic part 4 also includes a second portion. The second portion is connected along the height direction to the side of the first portion 401 away from the cover plate body 1. The second portion is used to abut against the pole assembly and can improve the structural strength of the first plastic part 4.

[0058] In one embodiment, h1, h2, h3, and h0 satisfy the following relationship: 0.05 ≤ [h3 - (h1 + h2)] / h0 ≤ 0.15. Here, h1, h2, h3, and h0 are all in mm. The upper surface of the sealing ring 3 is higher than the upper surface of the cover plate body 1 by a certain distance. [h3 - (h1 + h2)] / h0 represents the ratio of the distance between the upper surface of the sealing ring and the upper surface of the cover plate body 1 to the height of the rod portion 221 of the electrode post 2. By setting the upper surface of the sealing ring 3 higher than the upper surface of the cover plate body 1, it can prevent external liquid from entering the area between the sealing ring 3 and the electrode post hole 101, thus preventing the electrode post 2 and the cover plate body 1 from becoming conductive and causing poor cell performance. If [h3 - (h1 + h2)] / h0 < 0.05, then the sealing ring 3 is considered to be in good condition. If the distance between the sealing ring 3 and the upper surface of the cover plate body 1 is too small, the protection is insufficient, and the risk of external liquid entering the cover plate assembly and conducting through the cover plate body 1 and the pole post 2 increases. If [h3-(h1+h2)] / h0>0.15, the distance between the sealing ring 3 and the upper surface of the cover plate body 1 is too large. The area reserved on the rod 221 for setting the protrusion 222 is insufficient in the height direction, and the protrusion 222 is too small in the height direction, resulting in insufficient structural strength of the protrusion 222. It is easily damaged during assembly and cannot achieve the effect of preventing the sealing ring 3 from scraping and flipping. Ultimately, the cover plate assembly fails the helium test.

[0059] Therefore, by limiting the value of [h3-(h1+h2)] / h0 to within the range of 0.05 to 0.15, it is possible to ensure that the sealing ring 3 has sufficient dimensions along the height direction, effectively preventing external liquid from entering the area between the sealing ring 3 and the electrode post hole 101 and causing the electrode post 2 and the cover plate body 1 to conduct, thus avoiding poor cell performance. At the same time, it is also possible to ensure that the convex edge 222 has sufficient dimensions along the height direction, thereby ensuring the structural strength of the convex edge 222 and providing effective protection for the sealing ring 3 during the assembly of the cover plate assembly, thus ensuring that the sealing ring 3 is not damaged and ensuring the sealing performance of the sealing ring 3 and the reliability of the cover plate assembly.

[0060] In one embodiment, the value of h1 is in the range of 0.5 mm ≤ h1 ≤ 1.5 mm. If h1 < 0.5 mm, the distance between the plate 210 of the pole post 2 and the cover plate body 1 is too short, and the insulation effect of the first plastic part 4 on the plate 210 and the cover plate body 1 is insufficient, which poses a risk of conduction between the cover plate body 1 and the pole post 2. If h1 > 1.5 mm, the thickness of the first portion 401 is too large, and the distance between the plate 210 of the pole post 2 and the cover plate body 1 is too large, resulting in an excessive weight and volume of the cover plate assembly, which is not conducive to improving the volumetric energy density of the battery cell. Furthermore, due to the shrinkage characteristics of the injection molding material, the first plastic part 4 may shrink and deform severely when it is too thick, which may easily lead to poor assembly. Therefore, by limiting h1 to a value within the range of 0.5 mm to 1.5 mm, it is possible to ensure that the first plastic part 4 can provide sufficient insulation between the plate 210 and the cover plate body 1, preventing the cover plate body 1 from conducting with the electrode post 2. It is also possible to avoid the first plastic part 4 being too thick, which would lead to severe shrinkage and deformation, thus ensuring the reliability of the cover plate assembly. Furthermore, it is possible to avoid the overall weight and volume of the cover plate assembly being too large, which is beneficial to improving the volumetric energy density of the battery cell.

[0061] In one embodiment, the value of h2 ranges from 1.5 mm to 3 mm. It should be noted that h2 is the total thickness of the cover plate body 1 along the height direction. If h2 < 1.5 mm, the cover plate body 1 is too thin, resulting in poor structural strength, easy deformation, and likely flatness deviations. If h2 > 3 mm, the cover plate body 1 is too thick, leading to design redundancy, higher weight and cost, and a larger space requirement along the height direction, restricting layout and hindering the improvement of the cell's volumetric energy density. Therefore, by limiting h2 to a value between 1.5 mm and 3 mm, sufficient structural strength of the cover plate body 1 can be ensured, preventing deformation and ensuring flatness meets requirements. Simultaneously, the weight and cost of the cover plate body 1 can be controlled, avoiding excessive space occupation along the height direction, which is beneficial for improving the cell's volumetric energy density.

[0062] In one embodiment, the value of h3 is in the range of 2 mm ≤ h3 ≤ 5 mm. It should be noted that h3 is the vertical distance between the lower surface of the convex edge 222 and the upper surface of the plate 210, which is also equal to the total dimension of the sealing ring 3 along the height direction, i.e., the protective height of the sealing ring 3. If h3 < 2 mm, the dimension of the sealing ring 3 along the height direction is too small and cannot provide effective protection along the height direction. Correspondingly, the dimensions of the cover plate body 1 and the first portion 401 along the height direction will also decrease, resulting in a decrease in the insulation, strength, and other performance of the cover plate assembly. If h3 > 5 mm, the total dimension of the sealing ring 3 along the height direction is too large. Correspondingly, the total dimension of the cover plate assembly along the height direction is too large, resulting in an excessively large cover plate assembly volume, which affects the overall structural layout of the battery cell. Therefore, by limiting h3 to a value between 2 mm and 5 mm, it is possible to ensure that the cover plate assembly has good insulation, strength, and other performance, while also avoiding an excessively large cover plate assembly volume, thus facilitating the overall structural layout of the battery cell.

[0063] In one embodiment, the value of h0 is in the range of 3 mm ≤ h0 ≤ 6 mm. If h0 is less than 3 mm, the dimension of the rod 221 along the height direction is too small, resulting in insufficient installation space for the sealing ring 3 and poor sealing performance of the cover assembly. If h0 is greater than 6 mm, the dimension of the rod 221 along the height direction is too large, leading to an excessively large overall dimension of the cover assembly along the height direction, which occupies too much cell space and is not conducive to improving the volumetric energy density of the cell. Therefore, by limiting h0 to a value between 3 mm and 6 mm, it is possible to ensure that the rod 221 provides sufficient installation space for the sealing ring 3 along the height direction, thereby ensuring the sealing performance of the cover assembly, while avoiding an excessively large dimension of the rod 221 along the height direction, which would result in an excessively large dimension of the cover assembly along the height direction and thus avoid occupying too much cell space, which is beneficial to improving the volumetric energy density of the cell.

[0064] The following examples illustrate the impact of different values ​​of [h3-(h1+h2)] / h0 on the performance of the cover plate assembly. The test results of the embodiments and comparative examples are shown in Tables 1 to 3. In the embodiments, the cover plate assembly satisfies the relationship 0.05≤[h3-(h1+h2)] / h0≤0.15; the cover plate assembly of the comparative examples does not satisfy the relationship 0.05≤[h3-(h1+h2)] / h0≤0.15.

[0065] Case 1: The dimension h0 of the rod 221 along the height direction is 3.4 mm, the dimension h1 of the first portion 401 of the first plastic part 4 along the height direction is 0.7 mm, and the dimension h2 of the cover body 1 along the height direction is 2 mm. By changing the distance h3 (i.e., the sealing ring protection height) between the convex edge 222 and the plate 210 along the height direction, [h3-(h1+h2)] / h0 takes different values. Test the resistance of the cover assembly after it is contaminated by liquid (resistance R ≥ 200 mΩ) and the helium leak detection rate data (≤ 1×10⁻⁶). - 7 Pa.m 3 The test results ( / s) are shown in Table 1.

[0066] Table 1

[0067]

[0068] Case 2: h0 = 4 mm, h1 = 0.8 mm, h2 = 2.5 mm. By changing h3, [h3 - (h1 + h2)] / h0 takes different values. Test the resistance of the cover plate assembly after it is contaminated by liquid (resistance R ≥ 200 mΩ), and the helium detection data (≤ 1 × 10⁻⁶). -7 Pa.m 3 The test results ( / s) are shown in Table 2.

[0069] Table 2

[0070]

[0071] Case 3: h0 = 3 mm, h1 = 0.7 mm, h2 = 1.5 mm. By changing h3, [h3 - (h1 + h2)] / h0 takes different values. Test the resistance of the cover plate assembly after it is contaminated by liquid (resistance R ≥ 200 mΩ), and the helium detection data (≤ 1 × 10⁻⁶). -7 Pa.m 3 The test results ( / s) are shown in Table 3.

[0072] Table 3

[0073]

[0074] As can be seen from Tables 1 to 3, in Examples 1-1 to 1-5, Examples 2-1 to 2-5, and Examples 3-1 to 3-5, the value of [h3-(h1+h2)] / h0 is within the range of 0.05 to 0.15 as defined in this application. The resistance of the cover plate assembly after being contaminated by liquid is greater than or equal to 200 mΩ, and the helium leak detection rate of the cover plate assembly is less than or equal to 1×10⁻⁶. - 7 Pa.m 3 / s, meaning that both resistance and helium detection meet the requirements; however, in Comparative Examples 1-1 to 1-3, Comparative Examples 2-1 to 2-3, and Comparative Examples 3-1 to 3-3, the value of [h3-(h1+h2)] / h0 is less than 0.05, which is outside the range specified in this application. Although the helium leak detection rate of the cover plate assembly is less than 1×10 -7 Pa.m 3 / s, but the resistance is less than 200 mΩ, which does not meet the requirements; in Comparative Examples 1-4 to 1-6, Comparative Examples 2-4 to 2-6, and Comparative Examples 3-4 to 3-6, the value of [h3-(h1+h2)] / h0 is greater than 0.15, which is not within the range limited by this application. Although the resistance is greater than 200 mΩ, the leakage rate of the cover plate assembly is greater than 1×10 -7 Pa.m 3 / s does not meet the requirements.

[0075] In summary, when [h3-(h1+h2)] / h0 takes a value in the range of 0.05 to 0.15, the resistance and helium detection of the cover plate assembly after being contaminated by liquid both meet the requirements, and the performance of the cover plate meets the requirements.

[0076] In one embodiment, the rod 221 is racetrack-shaped or cylindrical, further combined with... Figure 7 and 8 As shown, the orthographic projection of the rod 221 along the height direction onto the plate 210 includes at least two semicircular regions 2211 arranged opposite each other along the length direction. The radius of the semicircular region 2211 is r, and the circumference width of the convex edge 222 is a. The relationship between a and r is: 0.1 ≤ a / r ≤ 0.2. Here, the length direction refers to... Figures 7 to 8 The "length direction" indicated by the middle arrow refers to the height direction. Figure 7 The arrow points to the "height direction". If a / r < 0.1, the ring width of the convex edge 222 is too small, increasing the processing difficulty of the convex edge 222 and failing to provide effective protection for the sealing ring 3. The sealing ring 3 is still prone to collision with the cover plate body 1. If a / r is greater than 0.2, the convex edge 222 occupies too much space in the pole post 2, significantly affecting the cross-sectional area of ​​the rod 221. This results in the cross-sectional area of ​​the rod 221 being too small in the section perpendicular to the height direction, affecting the structural strength and flow capacity of the pole post 2.

[0077] Therefore, by limiting a / r to a value between 0.1 and 0.2, it is possible to ensure that the flange 222 can be smoothly processed and formed, and to provide effective protection for the sealing ring 3 during the assembly of the cover plate assembly, so as to prevent the sealing ring 3 from being damaged by the cover plate body 1. It is also possible to avoid the flange 222 having an excessively large ring width, which would result in the rod 221 having an excessively small cross-sectional area, thereby ensuring that the pole post 2 has good structural strength and current carrying capacity.

[0078] In one embodiment, such as Figure 8 As shown, the pole 221 is racetrack shaped. The orthographic projection of the pole 221 along its height onto the plate 210 includes two semicircular regions 2211 arranged opposite each other along its length, and a rectangular region 2212 connecting the two semicircular regions 2211. The boundary line between the semicircular region 2211 and the rectangular region 2212 is as follows: Figure 8 As shown by the dotted lines, it should be noted that the dotted lines are only for illustration and do not actually exist; correspondingly, the inner and outer rings of the ring formed by the convex edge 222 are both runway-shaped.

[0079] In other embodiments, the rod 221 may also be cylindrical, and the orthographic projection of the rod 221 on the plate 210 along the height direction is circular, including only two semi-circular areas 2211 arranged opposite each other along the length direction. Correspondingly, the ring formed by the protruding edge 222 is a circular ring.

[0080] In one embodiment, the value of a ranges from 0.3 mm to 2.5 mm. If a < 0.3 mm, the protective width of the flange 222 for the sealing ring 3 is too small, and the sealing ring 3 may still be scraped and flipped by the cover plate body 1. At the same time, the flange 222 is difficult to process and is not easy to form. If a > 2.5 mm, the ring width of the flange 222 is too large, resulting in the cross-sectional area of ​​the rod 221 in the section perpendicular to the height direction being too small, which affects the current carrying capacity of the pole post 2, resulting in excessively high charging and discharging temperatures and poor cell safety. Therefore, by limiting the value of 'a' to the range of 0.3 mm to 2.5 mm, it is possible to ensure that the protruding edge 222 can be smoothly processed and formed, and to provide effective protection for the sealing ring 3 during the assembly of the cover plate assembly, preventing the sealing ring 3 from being scraped and flipped by the cover plate body 1, thereby ensuring the sealing performance of the cover plate assembly. At the same time, it is possible to avoid the protruding edge 222 having an excessively large ring width, which would result in the cross-sectional area of ​​the rod 221 being too small, thereby ensuring that the pole post 2 has good structural strength and current carrying capacity, avoiding excessively high charging and discharging temperatures of the battery cell, and improving the safety of the battery cell.

[0081] In one embodiment, the value of r is in the range of 2 mm ≤ r ≤ 20 mm. If r is less than 2 mm, the size of the semicircular region 2211 on the cross-section of the rod 221 is too small, resulting in a small cross-sectional area of ​​the rod 221, making it difficult to rivet the pole post 2, causing large riveting offset and uneven material expansion. If r is greater than 20 mm, the cross-sectional area of ​​the rod 221 is too large, making it difficult to rivet the pole post 2 and increasing the riveting difficulty. Therefore, by limiting r to a value between 2 mm and 20 mm, it is possible to ensure that the cross-section of the rod 221 of the pole post 2 has a reasonable size, ensuring that the pole post 2 can be riveted smoothly.

[0082] In one embodiment, the cover plate assembly further includes a riveting block 5, which is disposed on the side of the cover plate body 1 away from the plate body 210. The riveting block 5 has a riveting hole 501 corresponding to the pole post hole 101. The head 223 of the pole 220 passes through the riveting hole 501 and is riveted to the riveting block 5. By providing the riveting block 5 on the side of the cover plate body 1 away from the plate body 210, and riveting the head 223 of the pole post 2 to the riveting block 5, the pole post 2 and the riveting block 5 are fixedly connected. At the same time, the plate body 210 is limited to the side of the cover plate body 1 away from the riveting block 5, thereby limiting the cover plate body 1, the pole post 2 and the riveting block 5 to each other.

[0083] It should be noted that the riveting hole 501 includes a third hole segment and a fourth hole segment. The third hole segment is connected to the end of the fourth hole segment near the cover plate body 1. The opening area of ​​the third hole segment is smaller than that of the fourth hole segment. After riveting, the head 223 of the pole post 2 forms a first column segment corresponding to the third hole segment and a second column segment corresponding to the fourth hole segment. The cross-sectional area of ​​the second column segment is larger than that of the first column segment, thereby realizing the riveting of the pole post and the riveting block 5.

[0084] In one embodiment, the cover plate assembly further includes: a second plastic part 6, which is disposed on the side of the cover plate body 1 away from the first plastic part 4, and at least a portion of the second plastic part 6 is located between the riveting block 5 and the cover plate body 1 to ensure the insulation between the riveting block 5 and the cover plate body 1. The second plastic part 6 is provided with a second through hole 601 corresponding to the pole hole 101, and a portion of the rod 221 near the head 223 passes through the second through hole 601.

[0085] In one embodiment, the first plastic part 4 is the lower plastic part, and the second plastic part 6 is the upper plastic part.

[0086] In one embodiment, the cover assembly further includes an explosion-proof valve 7, and the cover body 1 is provided with an explosion-proof valve hole. The explosion-proof valve 7 is disposed in the explosion-proof valve hole. The explosion-proof valve 7 is adapted to open when the gas pressure inside the battery reaches a preset value, so as to timely discharge the high-temperature smoke in the battery and prevent the battery from exploding. An explosion-proof patch 8 is attached to the explosion-proof valve 7 to protect the explosion-proof valve.

[0087] In this embodiment, the cover plate assembly forms a protective structure by providing a raised edge 222 on the rod portion 221 of the pole post 2. This effectively protects the sealing ring 3 from being scratched during the assembly of the cover plate assembly, improves the sealing problem caused by the sealing ring 3 being bumped, squeezed, and flipped by the cover plate body 1 during the assembly of the cover plate, and improves the sealing performance and reliability of the cover plate assembly.

[0088] According to an embodiment of the present invention, in another aspect, a battery cell is also provided, comprising: a housing, an electrode assembly, and the aforementioned cover plate assembly. The housing has an open end; the electrode assembly is disposed within the housing; and the cover plate assembly covers the open end of the housing. Preferably, the battery cell is a lithium-ion battery cell, applicable to fields such as electric vehicles and energy storage.

[0089] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate body has pole hole; An electrode post includes a plate and a post. The plate is located on one side of the cover plate body. The post includes a rod and a head. The rod is connected between the plate and the head. At least a portion of the rod passes through the electrode post hole. An annular protrusion is provided on the outer circumferential surface of the rod. The protrusion surrounds the rod circumferentially and is spaced apart from the plate. A sealing ring is fitted on the outer periphery of the rod and along the height direction. The sealing ring is located between the convex edge and the plate. The sealing ring includes a first ring portion and a second ring portion. The first ring portion is connected to the side of the second ring portion away from the plate. At least a portion of the first ring portion passes through the pole hole. The ring width of the first ring portion is less than or equal to the ring width of the convex edge. Along the height direction, the distance between the convex edge and the plate is equal to the height of the sealing ring, and the side of the convex edge facing away from the plate is flush with the side of the rod facing away from the plate; The cover plate assembly further includes a first plastic part, which is disposed on the side of the cover plate body facing the plate body. The first plastic part includes at least a first portion sandwiched between the cover plate body and the plate body, and the first portion has a dimension of h1 along the height direction. The cover plate body has a height dimension of h2, the distance between the protruding edge and the plate body has a height dimension of h3, and the rod has a height dimension of h0. The relationship between h1, h2, h3, and h0 is: h1 + h2 < h3 < h0.

2. The cover plate assembly according to claim 1, characterized in that, The relationship between h1, h2, h3, and h0 is: 0.05≤[h3-(h1+h2)] / h0≤0.

15.

3. The cover plate assembly according to claim 2, characterized in that, The value range of h1 is: 0.5 mm ≤ h1 ≤ 1.5 mm; And / or, the range of h2 is: 1.5 mm ≤ h2 ≤ 3 mm; And / or, the range of h3 is: 2 mm ≤ h3 ≤ 5 mm; And / or, the range of h0 is: 3 mm ≤ h0 ≤ 6 mm.

4. The cover plate assembly according to claim 1, characterized in that, The rod is in the shape of a racetrack or a cylinder. The orthographic projection of the rod onto the plate along the height direction includes at least two semicircular areas arranged opposite each other along the length direction. The radius of the semicircular area is r, and the ring width of the convex edge is a. The relationship between a and r is: 0.1≤a / r≤0.

2.

5. The cover plate assembly according to claim 4, characterized in that, The range of values ​​for a is: 0.3 mm ≤ a ≤ 2.5 mm.

6. The cover plate assembly according to claim 4, characterized in that, The range of values ​​for r is: 2 mm ≤ r ≤ 20 mm.

7. The cover plate assembly according to any one of claims 1 to 6, characterized in that, The width of the first ring is equal to the width of the convex edge.

8. A battery cell, characterized in that, include: The shell has an open end; The electrode assembly is disposed within the housing; The cover assembly according to any one of claims 1 to 7, wherein the cover assembly covers the opening end of the housing.

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