Battery top cover, power battery and assembly process of battery top cover

Abstract

The invention relates to the technical field of batteries, and discloses a battery top cover, a power battery and an assembly process of the battery top cover. The battery top cover comprises a cover plate assembly and a pole. The cover plate assembly comprises an upper plastic part, a cover plate and a lower plastic part which are stacked in sequence. The upper plastic part, the cover plate and the lower plastic part are all provided with through holes. The pole comprises a base plate and a pole body, the base plate abuts against the surface of the cover plate assembly, and the pole body is connected with the base plate and penetrates through the through hole of the upper plastic part, the through hole of the cover plate and the through hole of the lower plastic part. The axis of the pole is perpendicular to the lower plastic part, and the outer side wall of the pole body is obliquely arranged relative to the axis of the pole from the end connected with the base plate to the end farthest from the base plate.

Description

[0001] This application is a divisional application filed in China on June 9, 2023, with application number 202310690166.X, entitled “Battery top cover, power battery and assembly process of battery top cover”. Technical Field

[0002] This invention relates to the field of battery technology, specifically to a battery top cover, a power battery, and an assembly process for the battery top cover. Background Technology

[0003] Battery top covers are primarily used in the power batteries of new energy vehicles. A battery top cover typically consists of a cover plate assembly and terminals. Assembly methods for the terminals and cover plate assembly include injection molding, riveting, and welding. Among these, riveted battery top covers have relatively more assembly processes, a complex structure, and cumbersome operation steps, resulting in lower production efficiency and insufficient capacity to meet the growing battery cell market. Injection-molded battery top covers are suitable for wider battery top covers but are easily limited by factors such as injection molding equipment, site conditions, and material molding processes, making them quite restrictive. Welded battery top covers fix the terminals and cover plate assembly together using laser welding, making the entire battery top cover a single unit. This connection is stable, the process is simple, and the cost is low, improving assembly efficiency and ensuring connection strength. However, during laser welding, there is a risk of direct laser beams burning the lower plastic component beneath the cover plate.

[0004] Therefore, there is an urgent need to provide an assembly process for the battery top cover, the power battery, and the battery top cover to solve the above problems. Summary of the Invention

[0005] The first objective of this invention is to provide a battery top cover that is stably connected by welding, which is simple in process, low in cost, and can also ensure the structural strength of the battery top cover.

[0006] The second objective of this invention is to provide a power battery that, by providing the aforementioned battery top cover, improves assembly efficiency, reduces costs, and also ensures the structural strength of the battery top cover.

[0007] The third objective of this invention is to provide an assembly process for a battery top cover, which is used to assemble the aforementioned battery top cover, has high assembly efficiency, reduces costs, and also ensures the structural strength of the battery top cover.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: Battery top cover, including: Cover plate assembly; The electrode and the pressure block are provided. The pressure block has a mounting hole. The electrode passes through the cover plate assembly and engages with the mounting hole. The surface of the pressure block has a welding groove that communicates with the periphery of the mounting hole. The electrode and the pressure block are fixed by welding. The welding groove is used to accommodate the welding residue. The pressure block and the electrode are respectively pressed against both sides of the cover plate assembly.

[0009] As an alternative, the cover plate assembly includes a stacked cover plate and a lower plastic part, the pressure block is disposed on the side of the cover plate opposite to the lower plastic part, the axis of the pole is perpendicular to the lower plastic part, and the outer side wall of the pole is inclined relative to the axis of the pole.

[0010] As an optional solution, the wall of the mounting hole and the outer wall of the pole post have the same inclination direction and inclination angle, and the outer wall of the pole post fits snugly against the wall of the mounting hole.

[0011] As an alternative, the angle θ between the outer wall of the pole and its axis is greater than 0° and less than or equal to 3°.

[0012] As an optional solution, the upper surface of the pressure block is set higher than the upper surface of the pole post, the welding groove is located above the mounting hole and is coaxially arranged with the mounting hole, and the radial dimension of the welding groove is larger than the radial dimension of the mounting hole.

[0013] As an optional solution, the electrode is divided into a negative electrode and a positive electrode. The negative electrode is integrally formed from a copper-aluminum composite plate by cold heading process, and the positive electrode is integrally formed from an aluminum plate by cold heading process.

[0014] As an alternative, the pole post includes a base and a pole post body that are coaxially arranged and have successively decreasing outer edge dimensions. The base is pressed against the surface of the cover plate assembly, and the pole post body mates with the mounting hole.

[0015] As an optional solution, a first groove is provided on the top of the pole body.

[0016] As an optional solution, the minimum distance W between the sidewall of the first groove and the outer sidewall of the pole body is greater than or equal to 2mm.

[0017] As an optional solution, the pole post includes a base, a lower column, and an upper column arranged coaxially with their outer edge dimensions decreasing sequentially. The base abuts against the side surface of the cover plate assembly opposite to the pressure block. The lower column passes through the cover plate assembly and abuts against the surface of the pressure block. The upper column mates with the mounting hole.

[0018] As an alternative, the top of the upper column is provided with a positioning groove for inserting an external fixture.

[0019] As an alternative, a second groove is formed on the bottom of the chassis.

[0020] As an alternative, the axial section of the second groove is arched, and the angle α between its circumferential sidewall and the horizontal plane is greater than or equal to 15° and less than or equal to 60°.

[0021] As an optional solution, the battery top cover also includes a connecting piece for connecting to the tabs of the battery cell, and the connecting piece is connected to the terminal post; The chassis has a stepped edge structure, and the connecting piece has stepped holes, which are matched with the stepped structure.

[0022] As an optional solution, the cover plate assembly includes an upper plastic part and a cover plate, the upper plastic part being disposed between the cover plate and the pressure block, and the pole passing through the cover plate and the upper plastic part in sequence and then engaging with the pressure block.

[0023] As an optional solution, the upper plastic part has a venting groove on the side that abuts against the pressure block, and the venting groove is connected to the mounting hole.

[0024] As an alternative, the upper plastic part has a receiving groove on the side near the pressure block, and a protrusion is formed on the side wall of the receiving groove. The pressure block is disposed in the receiving groove, and the protrusion abuts against the pressure block.

[0025] As an alternative, the battery top cover also includes a seal, which is fitted onto the terminal post and is used to seal the terminal post and the cover plate.

[0026] A power battery includes a casing, a battery cell, and a battery top cover as described in any one of the above, wherein the battery cell is disposed inside the casing, and the battery top cover is fastened to the opening end of the casing.

[0027] The assembly process for the battery top cover, used to assemble the battery top cover described in any of the above-mentioned embodiments, includes the following specific steps: Step S1: Fit the sealing element onto the pole; Step S2: Pass the electrode post with the sealing element installed through the cover plate assembly and mate it with the mounting hole of the pressure block; Step S3: Apply pressure to the top of the pole using a jig to cause the material at the top of the pole to flow outwards, so that the pole, the pressure block, and the cover plate assembly fit together tightly. Step S4: The pressure block and the pole are fixedly connected by welding.

[0028] As an optional solution, the cover assembly includes an upper plastic part, a cover plate, and a lower plastic part stacked sequentially, and step S2 specifically includes: Step S21: Place the lower plastic part under the cover plate, and pass the pole with the sealing element installed through the lower plastic part and the cover plate in sequence; Step S22: Place the upper plastic part above the cover plate and sleeve it onto the pole post; Step S23: Place the pressure block above the upper plastic part and sleeve it on the pole post.

[0029] The beneficial effects of this invention are as follows: The battery top cover provided by this invention has terminals that pass through the cover plate assembly and mate with mounting holes. By applying pressure to the entire battery top cover, all components are tightly fitted together, and then the pressure block is connected and fixed to the terminals through a welding process. This makes the entire battery top cover a single unit with a stable connection. The process is simple, low-cost, and improves the assembly efficiency of the battery top cover, while also ensuring the connection strength. The welding groove is used to accommodate welding residue and prevent it from protruding from the upper surface of the pressure block, thus ensuring the flatness and aesthetics of the battery top cover.

[0030] The power battery provided by the present invention improves assembly efficiency and reduces costs by setting the battery top cover, while also ensuring the structural strength and connection strength of the battery top cover.

[0031] The battery top cover assembly process provided by the present invention is used to assemble the above-mentioned battery top cover. It has high assembly efficiency, reduces costs, and can also ensure the structural strength of the battery top cover. Attached Figure Description

[0032] To more clearly and understandably illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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.

[0033] Figure 1 This is a schematic diagram of the structure of the battery top cover provided in Embodiment 1 of the present invention; Figure 2 This is an exploded view of the battery top cover provided in Embodiment 1 of the present invention; Figure 3 This is a top view of the battery top cover provided in Embodiment 1 of the present invention; Figure 4 yes Figure 3 Sectional view at point AA; Figure 5 yes Figure 4 A magnified view of a section at point B in the middle; Figure 6 This is a schematic diagram of the pole structure provided in Embodiment 1 of the present invention; Figure 7 This is an axial sectional view of the pole provided in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the structure of the pressure block provided in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram of the structure of the upper plastic part provided in Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the pole structure provided in Embodiment 2 of the present invention; Figure 11 This is a top view of the battery top cover provided in Embodiment 2 of the present invention; Figure 12 yes Figure 11 Sectional view at CC; Figure 13 yes Figure 12 A magnified view of a section at point D; Figure 14 This is a detailed flowchart of the assembly process of the battery top cover provided in Embodiment 1 of the present invention; Figure 15 This is a detailed flowchart of step S2 provided in Embodiment 1 of the present invention.

[0034] In the picture: 1. Cover plate assembly; 11. Upper plastic part; 111. Receiving groove; 112. Venting groove; 113. Protrusion; 12. Cover plate; 121. Explosion-proof valve hole; 13. Lower plastic part; 2. Pole post; 21. Base plate; 211. Second groove; 212. Stepped surface; 22. Pole post body; 221. First groove; 23. Lower column; 24. Upper column; 241. Positioning groove; 3. Pressure block; 31. Mounting hole; 32. Welding groove; 4. Sealing components; 5. Connecting piece; 51. Stepped hole; 6. Explosion-proof valve assembly; 61. Explosion-proof sheet; 62. Explosion-proof sheet film. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0039] Example 1 This embodiment provides a power battery, which is a square battery, comprising a casing, battery cells, and a battery top cover. The battery cells are disposed within the casing, and the battery top cover is fastened to the open end of the casing. The casing serves to support the battery cells, providing effective restraint and protection. The casing can be made of a conductive metal material, such as aluminum or aluminum alloy, and the battery top cover can be sealed to the casing by welding.

[0040] Specifically, such as Figure 1 and Figure 2As shown, the battery top cover includes a cover plate assembly 1, a terminal post 2, a pressure block 3, and a sealing element 4. The terminal post 2 and the pressure block 3 are respectively disposed on opposite sides of the cover plate assembly 1. The cover plate assembly 1 includes an upper plastic part 11, a cover plate 12, and a lower plastic part 13 stacked from top to bottom. The pressure block 3 is disposed on the side of the upper plastic part 11 away from the cover plate 12. The upper plastic part 11, the cover plate 12, and the lower plastic part 13 are all provided with through holes for the terminal post 2 to pass through. The pressure block 3 is formed with a mounting hole 31. In this embodiment, the cover plate 12 is a smooth aluminum sheet. The terminal post 2 passes through the through holes of the lower plastic part 13, the cover plate 12, and the upper plastic part 11 from bottom to top and then connects with the mounting hole 31 of the pressure block 3. The terminal post 2 and the pressure block 3 are fixed by laser welding. The pressure block 3 is pressed against the upper surface of the cover plate assembly 1, and the terminal post 2 is pressed against the lower surface of the cover plate assembly 1. The sealing element 4 is fitted onto the pole post 2 to seal the pole post 2 with the cover plate 12.

[0041] refer to Figure 2 The assembly process of the battery top cover is as follows: First, the sealing element 4 is fitted onto the upper part of the terminal post 2. Then, the lower plastic part 13 is placed below the cover plate 12. The terminal post 2 with the sealing element 4 fitted on it passes through the lower plastic part 13 and the cover plate 12 in sequence, so that the base plate 21 at the bottom of the terminal post 2 abuts against the lower surface of the lower plastic part 13. Then, the upper plastic part 11 is placed above the cover plate 12 and fitted onto the terminal post 2. Then, the pressure block 3 is placed above the upper plastic part 11 and fitted onto the terminal post 2. Then, pressure is applied to the top of the terminal post 2 through the fixture, so that the material at the top of the terminal post 2 flows to all sides, thereby making the components fit tightly together. Then, the pressure block 3 is connected and fixed to the terminal post 2 through laser welding process, so that the components are fixed into a whole and the connection is stable. Compared with the riveted top cover, the welding process is simple, the cost is low, the assembly efficiency of the battery top cover is improved, and the connection strength of the battery top cover can be guaranteed.

[0042] It should be noted that, as Figures 3 to 5 As shown, the cover plate 12 serves as the main support for the battery top cover, supporting other components. Figure 5 As shown, the upper plastic part 11 is embedded in the assembly gap between the pressure block 3 and the cover plate 12, serving as insulation and separating the pressure block 3 from the cover plate 12. This reduces the probability of external short circuits in the power battery and improves its safety performance. The lower plastic part 13 is located between the cover plate 12 and the base 21 of the terminal post 2, separating the cover plate 12 from the base 21 of the terminal post 2. This also serves as insulation and reduces the probability of external short circuits in the battery.

[0043] Further, refer to Figure 5The seal 4 has an annular stepped structure. The smaller portion of its outer diameter is embedded in the assembly gap between the cover plate 12 and the terminal post 2, while the larger portion's end face abuts against the lower surface of the cover plate 12. This design not only provides a seal but also insulates the cover plate 12 from the terminal post 2. The seal 4 has a certain degree of elasticity and is interference-fitted into the assembly gap between the cover plate 12 and the terminal post 2, which helps improve the overall sealing performance, preventing air from entering the battery and electrolyte leakage. The seal 4 is made of an acid- and alkali-resistant, high-temperature-resistant elastic material, such as fluororubber, which is resistant to electrolyte corrosion.

[0044] Furthermore, such as Figure 5 and Figure 8 As shown, a welding groove 32 is formed on the surface of the pressure block 3. The welding groove 32 is connected to the periphery of the mounting hole 31 and is used to accommodate the welding residue. Specifically, the upper surface of the pressure block 3 is higher than the upper surface of the terminal post 2. The welding groove 32 is circular and located above the mounting hole 31 and coaxially with it. The radial dimension of the welding groove 32 is larger than the radial dimension of the mounting hole 31, thus forming a stepped structure on the top of the pressure block 3. It can be understood that when welding the pressure block 3 and the terminal post 2, welding is performed on the top of the pressure block 3 along the joint between the terminal post 2 and the pressure block 3. Therefore, during welding, the aluminum material on the top of the terminal post 2 is extruded to form the welding residue. The welding groove 32 is used to accommodate the welding residue extruded during welding, preventing the welding residue from protruding from the upper surface of the pressure block 3, thereby ensuring the flatness and aesthetics of the battery top cover. In other embodiments, the shape of the welding groove 32 can also be square, elliptical or other irregular shape, as long as the outer edge size of the welding groove 32 is larger than the outer edge size of the mounting hole 31, and no specific limitation is made here.

[0045] like Figure 2 As shown, specifically, there are two terminals 2, one negative and one positive. The negative and positive terminals are used to conduct current to external electrical components. Correspondingly, there are two pressure blocks 3, two upper plastic parts 11, and two sealing parts 4, which cooperate with the corresponding terminals 2.

[0046] Furthermore, such as Figure 5As shown, the battery top cover also includes connecting pieces 5, which are located on the side of the lower plastic part 13 opposite to the cover plate 12. There are two connecting pieces 5: a positive connecting piece and a negative connecting piece. The connecting pieces 5 have a bent structure. One end of the positive connecting piece is used to fix it to the bottom of the positive terminal, and the other end is used to connect it to the positive tab of the battery cell. One end of the negative connecting piece is used to connect to the bottom of the negative terminal, and the other end is used to connect it to the negative tab of the battery cell, thereby enabling current conduction. It should be noted that since the positive connecting piece needs to be welded and fixed to the aluminum positive tab, it is preferably made of aluminum. Similarly, since the negative connecting piece needs to be welded and fixed to the copper negative tab, it is preferably made of copper.

[0047] Furthermore, combined Figure 5 and Figure 6 In this embodiment, the pole post 2 has a cap-shaped structure, including a base 21 and a pole post body 22 coaxially arranged with decreasing outer edge dimensions. The base 21 abuts against the lower surface of the cover plate 12 to form a limiting position, and the pole post body 22 mates with the mounting hole 31. Both the base 21 and the pole post body 22 are cylindrical structures, and the outer diameter of the base 21 is larger than the outer diameter of the pole post body 22. This allows the base 21 to abut against the lower surface of the cover plate 12 after the pole post body 22 passes through the cover plate assembly 1, thus providing a limiting effect. In other embodiments, the base 21 and the pole post body 22 can also be square, elliptical, or other irregular shapes, as long as the outer edge dimension of the base 21 is larger than the outer edge dimension of the pole post body 22. No specific limitations are imposed here.

[0048] Preferably, the terminal post 2 is a one-piece molded structure, thereby improving the structural strength of the terminal post 2. Simultaneously, it eliminates the need for assembling the chassis 21 and the terminal post body 22, simplifying the assembly process. Specifically, the negative terminal post is integrally molded from a copper-aluminum composite plate using a cold-forging process, and the positive terminal post is integrally molded from an aluminum plate using a cold-forging process. It is understood that one end of the positive terminal post needs to be welded and fixed to the aluminum positive electrode connecting piece; therefore, the positive terminal post can be made from a pure aluminum plate. One end of the negative terminal post needs to be welded and fixed to the copper negative electrode connecting piece; therefore, the negative terminal post is made from a copper-aluminum composite plate, with the upper half near the terminal post body 22 made of aluminum and the lower half near the chassis 21 made of copper for welding and fixing to the copper negative electrode connecting piece. By using a copper-aluminum composite plate for cold-forging the negative terminal post, the traditional friction welding connection process for negative terminal posts is eliminated, saving costs. The use of copper-aluminum composite plates also reduces the amount of copper used, lightening the weight of the battery top cover.

[0049] Furthermore, such as Figure 2 and Figure 7As shown, the axis of the pole post 2 is perpendicular to the lower plastic part 13, and the outer wall of the pole post 2 is inclined relative to the axis of the pole post 2. The inclined direction and inclined angle of the hole wall of the mounting hole 31 are the same as those of the outer wall of the pole post 2, and the outer wall of the pole post 2 fits snugly with the hole wall of the mounting hole 31. Here, the outer wall of the pole post 2 specifically refers to the outer wall of the pole post body 22, excluding the outer wall of the chassis 21. In this embodiment, as... Figure 7 As shown, the outer wall of the electrode post 2 is inclined from bottom to top towards the inside of the electrode post 2. In other embodiments, the outer wall of the electrode post 2 can also be inclined from bottom to top towards the direction away from the electrode post 2. The wall of the mounting hole 31 can be set with the same inclination direction and inclination angle. That is to say, the outer wall of the electrode post body 22 is a slope, and the wall of the mounting hole 31 is also a slope, so that the electrode post 2 and the mounting hole 31 are fitted together by the slope. On the one hand, the slope prevents the laser from directly burning the lower plastic part 13 during laser welding. On the other hand, the slope can form an interlock at the joint surface between the electrode post body 22 and the pressure block 3, thereby improving the structural strength of the battery cover.

[0050] Optionally, such as Figure 7 As shown, the angle θ between the outer wall of the electrode post body 22 and its axis is greater than 0° and less than or equal to 3°. For example, the angle θ is 1°, 2°, or 3°. The angle between the wall of the mounting hole 31 and its axis is also greater than 0° and less than or equal to 3°. For example, the angle is 1°, 2°, or 3°. By setting the inclination angle of the outer wall of the electrode post body 22 and the inclination angle of the wall of the mounting hole 31 within the above range, it is possible not only to prevent direct laser radiation from burning the lower plastic part 13 during laser welding, but also to form an interlock at the joint surface between the electrode post body 22 and the pressure block 3, thereby improving the structural strength of the battery cover.

[0051] Furthermore, such as Figure 6 and Figure 7 As shown, a first groove 221 is formed on the top of the electrode post body 22. Firstly, the first groove 221 reduces weight, thus lightening the battery top cover and achieving a lightweight design. Secondly, since the electrode post 2 is manufactured using a cold heading process, which deforms the blank to the same volume through cold extrusion, the first groove 221 is formed on the top of the electrode post body 22. This allows the material at the groove 221 to move towards the sides of the electrode post body 22, increasing the height of the electrode post body 22 to meet design dimensional requirements. The shape of the first groove 221 can be, but is not limited to, circular, square, elliptical, or other irregular shapes; it can be flexibly set according to requirements and is not specifically limited here.

[0052] Preferably, such as Figure 7As shown, the minimum distance W between the side wall of the first groove 221 and the outer side wall of the electrode body 22 is greater than or equal to 2mm. For example, the minimum distance W is 2mm, 3mm, 4mm, 5mm, 6mm or 7mm. This minimum distance W is also the minimum wall thickness of the electrode body 22. By setting the minimum wall thickness of the electrode body 22 within the above range, the electrode 2 can ensure structural strength to meet welding strength, thereby ensuring the structural strength of the battery top cover.

[0053] Furthermore, such as Figure 7 As shown, a second groove 211 is formed at the bottom of the chassis 21. Firstly, by extruding the second groove 211 at the bottom of the chassis 21, the material at the groove 211 can move towards both sides of the chassis 21 during the extrusion process, thereby increasing the diameter of the chassis 21 and making the dimensions around the groove 211 more complete to meet dimensional requirements. Secondly, since the negative electrode post is made of copper-aluminum composite plate through a cold heading process, during the extrusion of the blank, due to the difference in hardness between copper and aluminum (copper is harder than aluminum), the copper material will compress the aluminum material, easily forming a wavy joint surface at the junction of the copper and aluminum materials, thus affecting the structural strength of the negative electrode post. By extruding the second groove 211 at the bottom of the chassis 21, the copper-aluminum composite plate provides flow space for the copper material during the isovolute deformation process, reducing the compression of the aluminum material by the copper material, making the joint surface of the copper and aluminum materials smoother, thus ensuring the structural strength of the negative electrode post and making the root of the negative electrode post less prone to breakage. The shape of the second groove 211 can be, but is not limited to, a circle, a square, an ellipse or other irregular shapes. It can be flexibly set according to the needs, and no specific limitation is made here.

[0054] Preferably, such as Figure 7 As shown, the axial cross-section of the second groove 211 is arched, and the angle α between its circumferential sidewall and the horizontal plane is greater than or equal to 15° and less than or equal to 60°. For example, the angle α is 15°, 20°, 25°, 30°, or 40°. By setting the inclination angle of the circumferential sidewall of the second groove 211 within the above range, better fluidity of the copper material in the copper-aluminum composite plate can be provided, making it less likely for the root of the negative electrode post to break during the integral molding process, thereby ensuring the structural strength of the negative electrode post.

[0055] Furthermore, such as Figure 9As shown, the upper plastic part 11 has a venting groove 112 on one side abutting against the pressure block 3, and the venting groove 112 communicates with the mounting hole 31. After the bottom surface of the pressure block 3 is attached to the surface of the upper plastic part 11, there is a certain gap between the venting groove 112 and the pressure block 3. The venting groove 112 can discharge the heat generated during the welding process, preventing the pole post 2 or the pressure block 3 from deforming due to the inability of the heat to be discharged during the welding process. The venting groove 112 is shaped as an annular groove plus four straight grooves connected to the annular groove. In other embodiments, the venting groove 112 can also be other shapes, which can be flexibly set according to the requirements, and no specific limitation is made here.

[0056] Preferably, such as Figure 9 As shown, the upper plastic part 11 has a receiving groove 111 on the side near the pressure block 3. The pressure block 3 is placed in the receiving groove 111, thus limiting its position. The aforementioned venting groove 112 is located at the bottom of the receiving groove 111. After the pressure block 3 is placed in the receiving groove 111, the bottom surface of the pressure block 3 is in contact with the bottom surface of the receiving groove 111. Multiple protrusions 113 are formed on the side wall of the receiving groove 111, spaced apart circumferentially. The protrusions 113 are very thin and abut against the pressure block 3. When the pressure block 3 is placed in the receiving groove 111, the protrusions 113 can position the pressure block 3. The surface of the protrusions 113 can be set as an inclined surface, allowing the pressure block 3 to enter the receiving groove 111 along the surface of the protrusions 113, making operation more convenient. The specific number of protrusions 113 is not specifically limited here and can be flexibly set according to actual needs.

[0057] Further, refer to Figure 2 , Figure 5 and Figure 7 The chassis 21 has a stepped edge structure, and the connecting piece 5 has a stepped hole 51. The stepped structure mates with the stepped hole 51. Specifically, the stepped structure gives the chassis 21 two different outer diameters, and a stepped surface 212 is formed on the stepped structure. The stepped hole 51 also includes two holes of different diameters. When the chassis 21 mates with the connecting piece 5, the smaller outer diameter portion of the chassis 21 passes through the smaller diameter hole in the stepped hole 51, and the larger outer diameter portion of the chassis 21 mates with the larger diameter hole in the stepped hole 51. The stepped surface 212 of the chassis 21 mates with the stepped surface of the stepped hole 51. By adopting this arrangement, the positioning effect between the chassis 21 and the connecting piece 5 can be improved, and the mutual movement between the chassis 21 and the connecting piece 5 can be restricted after assembly, facilitating the subsequent assembly and welding process.

[0058] Furthermore, such as Figure 1 and Figure 2As shown, the battery top cover also includes an explosion-proof valve assembly 6, which includes an explosion-proof sheet 61 and an explosion-proof sheet film 62. The explosion-proof sheet 61 is assembled into the explosion-proof valve hole 121 of the cover plate 12 by welding. The explosion-proof sheet 61 can automatically and quickly release the pressure of the battery when the internal pressure rises, preventing the power battery from exploding and causing a safety accident. The explosion-proof sheet film 62 protects the explosion-proof sheet 61 and prevents external dust, water or other impurities from entering the explosion-proof sheet 61.

[0059] like Figure 14 and Figure 15 As shown, this embodiment also provides an assembly process for a battery top cover, used to assemble the aforementioned battery top cover, refer to... Figure 2 The specific steps include: Step S1: Install the sealing element 4 onto the pole 2; Step S2: Pass the pole post 2 with the sealed part 4 through the cover plate assembly 1 and mate it with the mounting hole 31 of the pressure block 3; Step S3: Apply pressure to the top of the pole post 2 using a jig to make the material at the top of the pole post 2 flow to the surrounding area, so that the pole post 2, the pressure block 3 and the cover plate assembly 1 fit together tightly. Step S4: Fix the pressure block 3 and the pole post 2 together by welding.

[0060] Specifically, step S2 includes: Step S21: Place the lower plastic part 13 under the cover plate 12, and pass the electrode post 2 with the sealing element 4 installed through the lower plastic part 13 and the cover plate 12 in sequence. After this step, the base plate 21 at the bottom of the electrode post 2 abuts against the lower surface of the lower plastic part 13.

[0061] Step S22: Place the upper plastic part 11 above the cover plate 12 and fit it onto the pole post 2; Step S23: Place the pressure block 3 above the upper plastic part 11 and fit it onto the pole post 2.

[0062] It should be noted that by applying pressure to the top of the terminal post 2 using a jig, the material at the top of the terminal post 2 flows to all sides, thereby ensuring that the terminal post 2, the pressure block 3, the upper plastic part 11, the cover plate 12, the lower plastic part 13, and the sealing part 4 are all tightly fitted together. Then, the pressure block 3 is connected and fixed to the terminal post 2 by laser welding, thus fixing all components into a whole with a stable connection. Compared with riveted top covers, the welding process is simple and low-cost, improving the assembly efficiency of the battery top cover, and also ensuring the connection strength and structural strength of the battery top cover.

[0063] Example 2 The battery top cover provided in this embodiment has a similar structure to the battery top cover provided in Embodiment 1. The similarities will not be repeated here. The differences are as follows: like Figures 10 to 13 As shown, in this embodiment, the pole post 2 is also integrally formed by cold heading. Specifically, the pole post 2 has a tower-shaped structure, which includes a base 21, a lower column 23, and an upper column 24 arranged coaxially with decreasing outer dimensions. The base 21 abuts against the side surface of the lower plastic part 13 facing away from the pressure block 3. The lower column 23 passes through the cover plate assembly 1 and abuts against the lower surface of the pressure block 3. The upper column 24 mates with the mounting hole 31, that is, the outer wall of the upper column 24 fits against the hole wall of the mounting hole 31. By setting the pole post 2 as a tower-shaped structure with decreasing outer diameter, the height of the pole post 2 can be increased based on the equal volume deformation of the cold heading process to meet the design size requirements. Among them, the base 21 and the upper column 24 are both cylindrical structures. In other embodiments, the base 21, the lower column 23, and the upper column 24 can also be square, elliptical, or other irregular shapes, as long as the decreasing outer dimensions are guaranteed. No specific limitation is made here.

[0064] Preferably, such as Figure 10 As shown, a positioning groove 241 is provided on the top of the upper column 24. The positioning groove 241 is used for the insertion and positioning of an external pressure fixture during welding. The shape of the positioning groove 241 can be, but is not limited to, circular, square, elliptical or other irregular shapes. It can be flexibly set according to the requirements and no specific limitation is made here.

[0065] It should be noted that the pole post 2 provided in this embodiment can also be applied to riveting processes, in which case the positioning groove 241 is used for positioning and insertion of the riveting fixture. For example... Figure 13 As shown, when the pole post 2 and the pressure block 3 are assembled, the riveting jig is inserted into the positioning groove 241 and squeezes the inside of the positioning groove 241 to laterally deform the end of the pole post 2. The top of the pole post 2 expands under pressure and fills the top of the pressure block 3. At the same time, the pressure block 3, which is in contact with the riveting jig, is also squeezed and deformed. The pressure block 3 expands under pressure and fills the position between the upper column 24 and the lower column 23, thereby forming a fastening between the pressure block 3 and the pole post 2, ultimately forming as shown. Figure 13 The riveting structure shown is then used to weld the column 24 and the pressure block 3 together, making the pole post 2 and the pressure block 3 more tightly connected, thus ensuring that the overall structure of the battery top cover is more stable.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery top cover, characterized in that, include: The cover assembly (1) includes an upper plastic part (11), a cover plate (12), and a lower plastic part (13) stacked sequentially, wherein the upper plastic part (11), the cover plate (12), and the lower plastic part (13) are all provided with through holes; and The pole (2) includes a chassis (21) and a pole body (22). The chassis (21) abuts against the surface of the cover plate assembly (1). The pole body (22) is connected to the chassis (21) and passes through the through hole of the upper plastic part (11), the through hole of the cover plate (12), and the through hole of the lower plastic part (13). The axis of the pole (2) is perpendicular to the lower plastic part (13). The outer side wall of the pole body (22) is inclined relative to the axis of the pole (2) from the end connected to the chassis (21) to the end furthest from the chassis (21).

2. The battery top cover according to claim 1, characterized in that, In the direction from the lower plastic part (13) to the upper plastic part (11), the outer wall of the pole body (22) is inclined toward the interior of the pole (2); or, In the direction from the lower plastic part (13) to the upper plastic part (11), the outer side wall of the pole body (22) is inclined in the direction away from the pole (2).

3. The battery top cover according to claim 1, characterized in that, The angle θ between the outer wall of the pole body (22) and the axis of the pole (2) is greater than 0° and less than or equal to 3°.

4. The battery top cover according to claim 1, characterized in that, The chassis (21) and the pole body (22) are coaxial, and the outer edge dimension of the chassis (21) is larger than the outer edge dimension of the pole body (22); and / or, The chassis (21) is circular, square, elliptical, or irregular in shape; and / or, The pole body (22) is circular, square, elliptical or irregular in shape.

5. The battery top cover according to any one of claims 1-4, characterized in that, The battery top cover also includes: A pressure block (3) is provided on the side of the cover plate (12) away from the lower plastic part (13). A mounting hole (31) is formed on the pressure block (3). The pole post (2) passes through the cover plate assembly (1) and engages with the mounting hole (31). The wall of the mounting hole (31) is inclined. The inclination direction and inclination angle of the wall of the mounting hole (31) and the outer wall of the pole post (2) are the same. The outer wall of the pole post (2) fits snugly with the wall of the mounting hole (31).

6. The battery top cover according to claim 5, characterized in that, The surface of the pressure block (3) is provided with a welding groove (32), which is connected to the periphery of the mounting hole (31). The pole post (2) and the pressure block (3) are fixed by welding. The welding groove (32) is used to accommodate the welding residue. The pressure block (3) and the pole post (2) are respectively pressed against the two sides of the cover plate assembly (1).

7. The battery top cover according to claim 6, characterized in that, The upper surface of the pressure block (3) is higher than the upper surface of the pole post (2), the welding groove (32) is located above the mounting hole (31) and is coaxial with the mounting hole (31), and the radial dimension of the welding groove (32) is greater than the radial dimension of the mounting hole (31).

8. The battery top cover according to claim 5, characterized in that, The upper plastic part (11) is disposed between the cover plate (12) and the pressure block (3). The upper plastic part (11) has an exhaust groove (112) on the side that abuts against the pressure block (3). The exhaust groove (112) is connected to the mounting hole (31). The upper plastic part (11) has a receiving groove (111) on the side that is close to the pressure block (3). A protrusion (113) is formed on the side wall of the receiving groove (111). The pressure block (3) is disposed in the receiving groove (111), and the protrusion (113) abuts against the pressure block (3).

9. The battery top cover according to any one of claims 1-3, characterized in that, The top of the pole body (22) is provided with a first groove (221), and the minimum distance W between the side wall of the first groove (221) and the outer side wall of the pole body (22) is greater than or equal to 2mm.

10. A power battery, characterized in that, The battery includes a housing, a battery cell, and a battery top cover as described in any one of claims 1-9, wherein the battery cell is disposed within the housing, and the battery top cover is fastened to the opening end of the housing.

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