Pin structure, cover plate assembly and secondary battery

Abstract

The utility model provides a pin structure, cover plate subassembly and secondary battery, the pin structure includes: a first connecting part and a second connecting part that are arranged at angle and mutually connected, the first connecting part is used for connecting tabs, the second connecting part is used for connecting poles, the thickness of the first connecting part is greater than that of the second connecting part. Therefore, the thickness of the second connecting part is thinned, so that the overcurrent capacity of the pin is improved, the quick charging requirement is met, and meanwhile, the occupied space in the height direction of the inner cavity of the battery cell is not increased.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a pin structure, a cover plate assembly, and a secondary battery. Background Technology

[0002] For narrow, elongated battery cells with low height, a pin structure is typically used to connect the tabs and terminals to ensure efficient use of internal space. Side-welded tabs, in particular, occupy less space and result in higher volumetric energy density. However, to meet the demands of fast charging, cells require higher current-carrying capacity, necessitating increased pin thickness. Existing pins are generally formed by stamping and bending sheet metal of uniform thickness. While uniformly thick pins enhance current-carrying capacity, they also increase overall thickness, directly occupying space in the height direction of the cell. Therefore, uniformly thick pins are not well-suited to the current-carrying capacity requirements of narrow, elongated, low-height cells under limited height space, leading to decreased internal space utilization. Utility Model Content

[0003] In view of this, the purpose of this utility model is to propose a pin structure, a cover plate assembly, and a secondary battery to improve the overcurrent capacity of the pins without increasing the space occupied in the height direction of the cell cavity, so as to at least partially solve the problems in the related technology.

[0004] To achieve the above objectives, a first aspect of the present invention provides a pin structure, comprising: a first connecting portion and a second connecting portion that are angled together and connected to each other, wherein the first connecting portion is used to connect to a tab, the second connecting portion is used to connect to a post, and the thickness of the first connecting portion is greater than the thickness of the second connecting portion.

[0005] Optionally, it also includes a bending transition portion, which is located between the first connecting portion and the second connecting portion and has the same thickness as the second connecting portion. The connection portion between the first connecting portion and the bending transition portion has a support platform, and the bending transition portion and the support platform form a storage area for accommodating the lower plastic edge portion.

[0006] The second aspect of this utility model also provides a cover plate assembly, characterized in that it includes: a lower plastic, an electrode post, a sealing ring, and a pin structure as described in the first aspect;

[0007] The lower plastic mounting portion is press-fitted onto the upper surface of the second connecting portion, and the mounting portion has a first through hole for the electrode post to pass through. The lower end of the electrode post is press-fitted into the mounting hole of the second connecting portion, and the sealing ring is sleeved on the electrode post.

[0008] Optionally, the pole includes a column and a press-fit plate surrounding the outer wall of the column. The mounting hole includes an interlocking hole and a press-fit hole that communicate with each other. The press-fit plate is press-fitted into the press-fit hole, and a portion of the column is interlocked into the interlocking hole.

[0009] Optionally, the sealing ring includes a sleeve portion and a sealing portion surrounding the outer wall of the sleeve portion. The sleeve portion has a second through hole through which the column body passes. After the lower plastic, the pole post, the sealing ring, and the pin structure are press-fitted, the sealing portion is located inside the first through hole.

[0010] Optionally, it also includes a light aluminum sheet, which is pressed onto the upper surface of the lower plastic and has a third through hole for the column to pass through. The diameter of the third through hole is smaller than the diameter of the first through hole, so that a portion of the light aluminum sheet is attached to the upper surface of the sealing part.

[0011] Optionally, the thickness of the mounting portion is equal to the first thickness of the sealing portion after compression;

[0012] The first thickness is equal to the original thickness of the sealing part minus the original thickness of the sealing part multiplied by the compression ratio of the sealing part.

[0013] Optionally, it also includes an adhesive backing that is adhered to the lower surface of the second connecting portion and the lower surface of the column.

[0014] Optionally, the thickness of the second connecting portion is equal to the total thickness of the lower plastic minus the sum of the thickness of the backing adhesive and the thickness of the mounting portion;

[0015] The pin structure includes a positive pin structure and a negative pin structure that are arranged opposite to each other along the length direction of the lower plastic.

[0016] The positive electrode pin structure includes a first positive electrode connection portion and a second positive electrode connection portion, wherein the ratio of the thickness of the second positive electrode connection portion to the thickness of the first positive electrode connection portion is less than 55%.

[0017] The negative electrode pin structure includes a first negative electrode connection portion and a second negative electrode connection portion, wherein the thickness of the second negative electrode connection portion is less than 35% of the thickness of the first negative electrode connection portion.

[0018] A third aspect of this invention also provides a secondary battery, including a cover assembly as described in the second aspect.

[0019] Through the above technical solution, the thickened pin structure is processed by a thinning process, so that the thickness of the first connection part used to connect the tab is greater than the thickness of the second connection part used to connect the post. That is, after the thinning process, the thickness of the second connection part connected to the post is reduced, thereby effectively reducing the space occupied in the height direction and ensuring the volumetric energy density of the cell. At the same time, the thickness of the first connection part is greater than the thickness of the second connection part, so that the first connection part has a stronger current carrying capacity and meets the overcurrent requirements of the cell during high current charging and discharging.

[0020] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the pin structure provided in an exemplary embodiment of this disclosure;

[0023] Figure 2 This is a cross-sectional view of the cover plate assembly provided in an exemplary embodiment of this disclosure;

[0024] Figure 3 yes Figure 2 Enlarged diagram of part A in the middle;

[0025] Figure 4 This is an exploded structural diagram of the cover plate assembly provided in an exemplary embodiment of this disclosure;

[0026] Figure 5 This is a schematic diagram of the structure of the cover plate assembly connecting the battery cell provided in an exemplary embodiment of this disclosure.

[0027] Explanation of reference numerals in the attached figures

[0028] 1-Pin structure; 101-First connecting part; 102-Second connecting part; 1021-Insertion hole; 1022-Pressure fitting hole; 103-Bending transition part; 104-Supporting platform; 105-Storage area; 2-Lower plastic; 201-First through hole; 202-Mounting part; 3-Electrical post; 301-Post; 302-Pressure fitting plate; 4-Sealing ring; 401-Sleeve part; 4011-Second through hole; 402-Sealing part; 5-Bright aluminum sheet; 501-Third through hole; 6-Back adhesive; 7-Upper plastic; 701-Fourth through hole; 8-Riveting block; 9-Battery cell. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Narrow, elongated, and low-profile battery cells prioritize high space utilization and energy density in their design. This is achieved by side-welding pins and tabs to reduce space occupancy in the height direction, thus increasing the cell's volumetric energy density. However, with increasing demands for fast charging, the cell's current-carrying capacity needs to be improved, directly requiring the pins to handle larger currents. Therefore, related technologies typically increase pin thickness to improve conductivity. However, this increased thickness further occupies space in the height direction, reducing the cell's volumetric energy density and creating a conflict between current-carrying capacity and space utilization. A common alternative is to use sheet metal of uniform thickness, formed through stamping and bending processes. However, while uniformly thick pins enhance current-carrying capacity, they also increase overall thickness, directly occupying space in the height direction. Therefore, uniformly thick pins cannot adequately meet the current-carrying capacity requirements of narrow, elongated, and low-profile cells with limited height space. Uniformly thick pins reduce the cell's internal space utilization, ultimately leading to a decrease in volumetric energy density.

[0032] Based on this, the first aspect of the present invention provides a pin structure 1, as shown in the reference. Figures 1 to 5 As shown, the pin structure 1 includes a first connecting portion 101 and a second connecting portion 102 that are angled and interconnected. The first connecting portion 101 is used to connect to the tab, and the second connecting portion 102 is used to connect to the terminal post 3. The thickness of the first connecting portion 101 is greater than the thickness of the second connecting portion 102. The thickened pin structure 1 is optimized by a thinning process so that the thickness of the first connecting portion 101 used to connect to the tab is greater than the thickness of the second connecting portion 102 used to connect to the terminal post 3. That is, after the thinning process, the thickness of the second connecting portion 102 connected to the terminal post 3 is reduced, thereby effectively reducing the space occupied in the height direction and ensuring the volumetric energy density of the cell 9. At the same time, the thickness of the first connecting portion 101 is greater than the thickness of the second connecting portion 102, so that the first connecting portion 101 has a stronger current carrying capacity and meets the overcurrent requirements of the cell 9 during high current charging and discharging.

[0033] In some implementations, reference Figures 1 to 3As shown, the pin structure 1 also includes a bending transition portion 103, which is located between the first connecting portion 101 and the second connecting portion 102. By setting the bending transition portion 103, the stress concentration problem between the first connecting portion 101 and the second connecting portion 102 can be effectively avoided, making the entire pin structure 1 smoother in the bending transition area, reducing mechanical stress, and enhancing the stability of the structure. Furthermore, the thickness of the bending transition portion 103 is consistent with the thickness of the second connecting portion 102. By maintaining the same thickness between the bending transition portion 103 and the second connecting portion 102, the stress concentration problem can be better alleviated, making the bending transition smoother and enhancing the mechanical strength of the entire structure. When the battery cell 9 is actually used, if the battery cell 9 is subjected to vibration or impact, the setting of the bending transition portion 103 makes the pin structure 1 more stable and reduces the risk of breakage caused by frequent use or vibration.

[0034] In some implementations, reference Figures 1 to 3 As shown, the connection between the first connecting part 101 and the bending transition part 103 has a support platform 104. The bending transition part 103 and the support platform 104 form a storage area 105 for accommodating the edge of the lower plastic 2. The support platform 104 is located at the connection between the first connecting part 101 and the bending transition part 103, thereby forming a storage area 105 for accommodating the edge of the lower plastic 2. That is, when the battery cell 9 is pressed into the shell, the storage area 105 can accommodate the edge of the lower plastic 2, providing a dedicated position for the edge of the lower plastic 2. This helps to prevent the lower plastic 2 from separating from the pins, enhances the sealing effect of the cover plate, prevents leakage of internal materials (such as electrolyte) of the battery cell 9, and also prevents external contaminants from entering the battery cell 9.

[0035] In some embodiments, the thickness of the bending transition portion 103 and the thickness of the second connecting portion 102 are reduced by a thinning process, thereby effectively reducing the space occupied in the height direction and ensuring the volumetric energy density of the battery cell 9.

[0036] Based on the above technical solutions, the second aspect of this utility model also provides a cover plate assembly, which includes: a lower plastic 2, an electrode post 3, a sealing ring 4, and a pin structure 1 as described in the first aspect or any embodiment of the first aspect. The mounting portion 202 of the lower plastic 2 is press-fitted onto the second connecting portion 102 of the pin structure 1 and a first through hole 201 is reserved for the electrode post 3 to pass through. This simplifies the assembly process, improves production efficiency and ease of installation. Simultaneously, the sealing ring 4 enhances the overall sealing performance of the battery cell 9. That is, by fitting the sealing ring 4 onto the electrode post 3, the cooperation between the sealing ring 4 and the lower plastic 2 and the electrode post 3 effectively enhances the sealing performance of the cover plate assembly, preventing electrolyte leakage and effectively blocking external moisture or contaminants from entering the battery cell 9. Furthermore, the lower end of the electrode post 3 is reliably connected to the second connecting portion 102 of the pin structure 1 through a press-fitting method, ensuring effective current conduction. Physical fastening also enhances the mechanical strength of the electrode post 3, preventing loosening or detachment due to vibration or impact during use.

[0037] In some embodiments, the pressing of the lower plastic 2 with the pin structure 1 and the pressing of the lower end of the terminal post 3 with the mounting hole of the second connection part 102 give the entire cover assembly high mechanical strength, thereby improving the battery's impact resistance during transportation, assembly and use, and reducing the risk of cell 9 damage due to loose structure.

[0038] In some implementations, reference Figures 2 to 4 As shown, the electrode post 3 includes a post body 301 and a press-fit plate 302 surrounding the outer wall of the post body 301. The mounting holes include interconnected insertion holes 1021 and press-fit holes 1022. The press-fit plate 302 is press-fitted into the press-fit holes 1022, and a portion of the post body 301 is inserted into the insertion holes 1021. By providing the press-fit plate 302 on the outer wall of the post body 301 and pressing it into the press-fit holes 1022, the electrode post 3 is more stable during installation, reducing the risk of loosening or falling off during use. Simultaneously, the tight fit between the press-fit plate 302 and the press-fit holes 1022 helps enhance the sealing effect between the electrode post 3 and the second connection part 102, effectively preventing electrolyte leakage or the entry of external contaminants. Furthermore, the insertion of a portion of the post body 301 into the insertion holes 1021 ensures tight contact between the post body 301 and the pin, optimizing the current conduction path, reducing resistance, and improving overcurrent capacity to meet high current requirements.

[0039] In some implementations, reference Figures 2 to 4As shown, the sealing ring 4 includes a sleeve portion 401 and a sealing portion 402 surrounding the outer wall of the sleeve portion 401. The sleeve portion 401 has a second through hole 4011 through which the post 301 passes. The sleeve portion 401 can ensure a stable connection between the sealing ring 4 and the post 3, and prevent the sealing ring 4 from shifting or falling off during battery use. The sealing portion 402 surrounds the outer wall of the sleeve portion 401 and is located inside the first through hole 201 of the lower plastic 2 after assembly. The sealing portion 402 can effectively seal the gap between the lower plastic 2 and the post 3, and play a role in preventing electrolyte leakage and preventing external moisture from entering.

[0040] Furthermore, the cover assembly also includes a light aluminum sheet 5, which is press-fitted onto the upper surface of the lower plastic 2 and has a third through hole 501 for the column 301 to pass through. The diameter of the third through hole 501 is smaller than the diameter of the first through hole 201, so that a portion of the light aluminum sheet 5 adheres to the upper surface of the sealing part 402. (Refer to...) Figure 3 As shown, after the cover plate assembly is assembled, the sealing part 402 is located between the aluminum sheet 5 and the pressure plate 302, and the sleeve part 401 is located inside the third through hole 501, so that the aluminum sheet 5 can be in close contact with the sealing ring 4. With the combined action of the aluminum sheet 5 and the sealing ring 4, the aluminum sheet 5 can effectively prevent water vapor, corrosive gases and dust and other impurities from entering the cell 9 through the sealing ring 4, thereby increasing the service life and safety of the cover plate assembly.

[0041] Furthermore, the aluminum sheet 5 is pressed onto the upper surface of the lower plastic 2, making it part of the cover assembly and increasing the strength of the entire cover assembly. The aluminum sheet 5 provides additional mechanical support to the cover assembly, especially at the connection between the pole post 3 and the lower plastic 2. The aluminum sheet 5 can withstand greater external impact, effectively protecting the sealing ring 4 and the pole post 3, and avoiding sealing failure due to impact.

[0042] At the same time, refer to Figure 3 and Figure 4 As shown, the cover assembly also includes an upper plastic sheet 7 and a riveting block 8. The upper surface of the aluminum sheet 5 has a groove for the upper plastic sheet 7 to fit into, and the upper plastic sheet 7 has a fourth through hole 701 for the electrode post 3 to pass through. The riveting block 8 is disposed on the upper surface of the upper plastic sheet 7 and is used to cover the electrode post 3. The riveting block 8 can fix the upper plastic sheet 7 through a riveting process and provide protection for the upper end of the electrode post 3. That is, the riveting block 8 covers the electrode post 3, which can not only withstand the impact force from the outside, but also evenly distribute the impact force from the outside, reducing the direct impact on the electrode post 3. Furthermore, the tight structural cooperation of the aluminum sheet 5, the riveting block 8, and the upper plastic sheet 7 further enhances the sealing performance of the cover assembly, preventing electrolyte leakage or moisture or dust impurities in the outside air from entering the cell 9, and improving the overall sealing performance of the cover assembly.

[0043] In some embodiments, during the press-fitting process of the cover plate assembly, to prevent overpressure on the sealing ring 4 and damage to it, the thickness of the sealing ring 4 needs to be dimensionally designed, referring to... Figure 3 As shown, based on the material properties of the lower plastic 2, the lower plastic 2 provides overpressure protection for the sealing part 402 of the sealing ring 4, preventing overpressure from occurring in the sealing part 402. The thickness of the mounting part 202 is equal to the first thickness of the sealing part 402 after compression. The first thickness is equal to the original thickness of the sealing part 402 minus the original thickness of the sealing part 402 multiplied by the compression ratio of the sealing part 402. That is, by reasonably designing the thickness of the sealing part 402 of the sealing ring 4 and the thickness of the mounting part 202 of the lower plastic 2, it can be ensured that the sealing ring 4 will not be damaged due to excessive compression during the pressing process. The compression ratio of the sealing ring 4 is obtained based on the physical properties of the material of the sealing ring 4 (such as the elastic modulus) to ensure that the sealing ring 4 can provide sufficient sealing effect after pressing without being damaged by excessive deformation.

[0044] In some embodiments, the compression rate of the sealing portion is 15% to 45%, wherein the compression rate is the ratio of the volume or thickness reduction of the sealing ring 4 when compressed to its original volume or thickness. The original thickness of the sealing ring 4 is reduced by 15% to 45% after compression. For example, the compression rate is at least 15% to ensure that the sealing ring 4 can fully fill the installation gap and avoid leakage of liquid or gas. At the same time, the compression rate does not exceed 45% to avoid damage or performance degradation of the sealing ring 4 due to over-compression. Furthermore, based on the material properties of the lower plastic 2, the lower plastic 2 can provide overpressure protection for the sealing portion 402 of the sealing ring 4, preventing overpressure from occurring in the sealing portion 402.

[0045] In some implementations, reference Figure 2 and Figure 3 As shown, the cover assembly also includes an adhesive backing 6, which improves the overall sealing effect of the cover assembly. Specifically, by adhering to the lower surfaces of the second connecting portion 102 and the pillar 301, the adhesive backing 6 further fills any gaps that may exist in this area, preventing air, moisture, or other contaminants from seeping into the cell 9. This seal effectively prevents leakage of the electrolyte inside the battery and blocks external contaminants from entering, thereby improving the overall sealing performance and durability of the battery. Furthermore, the adhesive backing 6 has a certain degree of softness and elasticity, providing shock absorption and cushioning when the battery cover assembly is subjected to external impacts or vibrations. This helps protect the pillar 301 and the second connecting portion 102 in the cover assembly, reducing mechanical damage or loosening caused by impacts, thereby extending the battery's lifespan.

[0046] In some embodiments, the adhesive 6 helps to fix the column 301 and the second connecting part 102 after assembly, preventing relative movement between the column 301 and the second connecting part 102. Simultaneously, based on its material properties, the adhesive 6 can also serve as an insulating layer, providing electrical isolation between the second connecting part 102 and the battery cell 9, thus improving the battery's safety and reliability.

[0047] In some implementations, the overall thickness of the pin structure 1 is increased to enable the pins to have good current carrying capacity, thereby meeting the user's fast charging requirements. In order to ensure the volumetric energy density of the battery cell 9, the second connection part 102 connected to the terminal post 3 needs to be thinned to reduce the thickness of the second connection part 102, thereby effectively reducing the space occupied in the height direction. Therefore, in order to ensure the compactness of the cover assembly in the height direction, the thickness of the second connection part 102 needs to be precisely controlled to match the total thickness of the lower plastic 2 and other components, thereby ensuring the compactness and stability of the entire cover assembly structure and avoiding structural loosening or stress concentration problems caused by uneven or mismatched thickness. That is, the thickness of the second connection part 102 is equal to the total thickness of the lower plastic 2 minus the sum of the thickness of the backing adhesive 6 and the thickness of the mounting part 202. Reasonable thickness distribution enhances the overall strength of the structure. In particular, when the cover assembly is subjected to external impact, it can more evenly disperse stress and reduce the risk of damage caused by local stress concentration.

[0048] In some implementations, reference Figure 4 and Figure 5As shown, cell 9 has a positive electrode tab and a negative electrode tab. The material selection and structural design of the positive and negative electrode tabs are crucial to the thermal management performance of the battery. The positive electrode tab is generally made of aluminum or aluminum alloy, which gives it good conductivity, lightweight and oxidation resistance, making it suitable for matching the electrochemical characteristics of the positive electrode material. The negative electrode tab is usually made of copper or nickel-plated copper, which gives it excellent conductivity and mechanical strength. Therefore, considering factors such as the special nature of the materials, in order to better adapt the pin structure to the positive and negative tabs of the battery cell 9, the pin structure includes a positive pin structure and a negative pin structure arranged opposite each other along the length direction of the lower plastic. The positive pin structure includes a first positive connection part and a second positive connection part, and the negative pin structure includes a first negative connection part and a second negative connection part. At the same time, in order to effectively reduce the space occupied by the second positive and second negative connection parts in the height direction, based on the material properties, the ratio of the thickness of the second positive connection part to the thickness of the first positive connection part is less than 55%, and the ratio of the thickness of the second negative connection part to the thickness of the first negative connection part is less than 35%. That is, by thinning the thickness of the second positive and second negative connection parts, the weight and volume of the battery can be optimized while ensuring battery performance, thereby improving the overall performance and service life of the battery.

[0049] Meanwhile, by rationally designing and planning the thickness dimensions of the second connecting part 102, the lower plastic 2, the mounting part 202 of the lower plastic 2, and the adhesive 6, the accuracy of each component in the cover plate assembly during assembly is ensured. At the same time, the second connecting part 102, the lower plastic 2, and the adhesive 6 can jointly form a balanced structural system, rationally distributing the thickness of each component within a limited height space, thereby reducing fatigue or damage caused by stress concentration.

[0050] Based on the above technical solutions, the third aspect of this utility model also provides a secondary battery, including the cover plate assembly of the second aspect.

[0051] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the scope of this invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of this invention as described above, which are not provided in the details for the sake of brevity.

[0052] The embodiments of this utility model are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A pin structure, characterized in that, include: A first connecting part and a second connecting part are arranged at an angle and connected to each other. The first connecting part is used to connect to the electrode tab, and the second connecting part is used to connect to the electrode post. The thickness of the first connecting part is greater than the thickness of the second connecting part.

2. The pin structure according to claim 1, characterized in that, It also includes a bending transition portion, which is located between the first connecting portion and the second connecting portion and has the same thickness as the second connecting portion. The connection between the first connecting portion and the bending transition portion has a support platform, and the bending transition portion and the support platform form a storage area for accommodating the lower plastic edge portion.

3. A cover plate assembly, characterized in that, include: The lower plastic component, the electrode post, the sealing ring, and the pin structure according to claim 1 or 2; The lower plastic mounting portion is press-fitted onto the upper surface of the second connecting portion, and the mounting portion has a first through hole for the electrode post to pass through. The lower end of the electrode post is press-fitted into the mounting hole of the second connecting portion, and the sealing ring is sleeved on the electrode post.

4. The cover plate assembly according to claim 3, characterized in that, The pole includes a column and a press-fit plate surrounding the outer wall of the column. The mounting hole includes an interlocking hole and a press-fit hole that are interconnected. The press-fit plate is press-fitted into the press-fit hole, and a portion of the column is interlocked into the interlocking hole.

5. The cover plate assembly according to claim 4, characterized in that, The sealing ring includes a sleeve portion and a sealing portion surrounding the outer wall of the sleeve portion. The sleeve portion has a second through hole through which the column body passes. After the lower plastic, the pole post, the sealing ring and the pin structure are press-fitted, the sealing portion is located inside the first through hole.

6. The cover plate assembly according to claim 5, characterized in that, It also includes a light aluminum sheet, which is pressed onto the upper surface of the lower plastic and has a third through hole for the column to pass through. The diameter of the third through hole is smaller than the diameter of the first through hole, so that part of the light aluminum sheet is attached to the upper surface of the sealing part.

7. The cover plate assembly according to claim 5, characterized in that, The thickness of the mounting portion is equal to the first thickness of the sealing portion after compression; The first thickness is equal to the original thickness of the sealing part minus the original thickness of the sealing part multiplied by the compression ratio of the sealing part.

8. The cover plate assembly according to claim 7, characterized in that, It also includes an adhesive backing, which is adhered to the lower surface of the second connecting portion and the lower surface of the column.

9. The cover plate assembly according to claim 8, characterized in that, The thickness of the second connecting part is equal to the total thickness of the lower plastic minus the sum of the thickness of the backing adhesive and the thickness of the mounting part; The pin structure includes a positive pin structure and a negative pin structure that are arranged opposite to each other along the length direction of the lower plastic. The positive electrode pin structure includes a first positive electrode connection portion and a second positive electrode connection portion, wherein the ratio of the thickness of the second positive electrode connection portion to the thickness of the first positive electrode connection portion is less than 55%. The negative electrode pin structure includes a first negative electrode connection portion and a second negative electrode connection portion, wherein the thickness of the second negative electrode connection portion is less than 35% of the thickness of the first negative electrode connection portion.

10. A secondary battery, characterized in that, Includes the cover plate assembly as described in any one of claims 3 to 9.

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