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, a pole and a pressing block, a mounting hole is formed in the pressing block, the pole penetrates through the cover plate assembly and then is matched with the mounting hole, a welding groove is formed in the surface of the pressing block, the welding groove is communicated with the peripheral side of the mounting hole, the pole and the pressing block are fixed through welding, and the pressing block and the pole abut against the two sides of the cover plate assembly respectively. According to the battery top cover, the pole and the pressing block are fixed by welding, so that the whole battery top cover becomes a whole, the connection is stable, the 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 ensured. And the welding groove is used for accommodating the welding melt part and preventing the welding melt part from protruding out of the upper surface of the pressing block, so that the appearance smoothness and attractiveness of the battery top cover are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery top cover, a power battery and an assembly process of the battery top cover. Background Art

[0002] Battery top covers are mainly used in power batteries in new energy vehicles. The traditional assembly methods of existing battery top covers are mainly injection molding and riveting. Among them, the assembly process of riveted battery top covers is relatively more, and the structure is complex, the operation steps are cumbersome, the production efficiency of battery top covers is low, and the production capacity cannot meet the problem of the growing battery cell market. Injection molding battery top covers are suitable for wider battery top covers, and are easily restricted by many factors such as injection molding equipment, site, material molding process, etc., and have great limitations.

[0003] Therefore, it is urgent to provide a battery top cover, a power battery and an assembly process of the battery top cover to solve the above problems. Summary of the invention

[0004] The first object of the present invention is to provide a battery top cover which is stably connected by welding, has a simple process, low cost, and can also ensure the structural strength of the battery top cover.

[0005] The second object of the present invention is to provide a power battery, which improves assembly efficiency, reduces costs, and ensures the structural strength of the battery top cover by providing the above-mentioned battery top cover.

[0006] The third object of the present invention is to provide an assembly process for a battery top cover, which is used to assemble the above-mentioned battery top cover, has high assembly efficiency, reduces costs, and can also ensure the structural strength of the battery top cover.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] Battery cover, including:

[0009] Cover plate assembly;

[0010] A pole and a pressure block, wherein a mounting hole is formed on the pressure block, and the pole matches with the mounting hole after passing through the cover plate assembly, and a welding groove is opened on the surface of the pressure block, and the welding groove is connected to the peripheral side of the mounting hole. The pole and the pressure block are fixed by welding, and the welding groove is used to accommodate the welding molten part, and the pressure block and the pole are respectively pressed against the two sides of the cover plate assembly.

[0011] As an optional solution, the cover plate assembly includes a stacked cover plate and a lower plastic part, the pressing block is arranged on the side of the cover plate away from 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.

[0012] As an optional solution, the inclination direction and inclination angle of the hole wall of the mounting hole and the outer side wall of the pole are the same, and the outer side wall of the pole fits closely with the hole wall of the mounting hole.

[0013] As an optional solution, the angle θ between the outer side wall of the pole and its axis is greater than 0° and less than or equal to 3°.

[0014] As an optional solution, the upper surface of the pressing block is arranged higher than the upper surface of the pole, the welding groove is located above the mounting hole and coaxially arranged with the mounting hole, and the radial dimension of the welding groove is larger than the radial dimension of the mounting hole.

[0015] As an optional solution, the pole is divided into a negative pole and a positive pole, the negative pole is integrally formed from a copper-aluminum composite plate by a cold heading process, and the positive pole is integrally formed from an aluminum plate by a cold heading process.

[0016] As an optional solution, the pole includes a chassis and a pole body which are coaxially arranged and have outer edge sizes decreasing successively, the chassis is pressed against the surface of the cover plate assembly, and the pole body is matched with the mounting hole.

[0017] As an optional solution, a first groove is formed on the top of the pole body.

[0018] As an optional solution, the minimum distance W between the side wall of the first groove and the outer side wall of the pole body is greater than or equal to 2 mm.

[0019] As an optional solution, the pole includes a chassis, a lower column and an upper column which are coaxially arranged and have decreasing outer edge sizes in sequence. The chassis is pressed against the side surface of the cover plate assembly facing away from the pressure block, the lower column passes through the cover plate assembly and abuts against the surface of the pressure block, and the upper column cooperates with the mounting hole.

[0020] As an optional solution, a positioning groove is provided on the top of the upper column, and the positioning groove is used for inserting an external fixture.

[0021] As an optional solution, a second groove is formed at the bottom of the chassis.

[0022] As an optional solution, the axial cross-section of the second groove is arched, and the angle α between the circumferential side wall thereof and the horizontal plane is greater than or equal to 15° and less than or equal to 60°.

[0023] As an optional solution, a chamfer is provided on a side of the pressing block away from the welding groove and at an edge of the mounting hole.

[0024] As an optional solution, the battery top cover further includes a connecting piece, the connecting piece is used to be connected to the pole ear of the battery cell, and the connecting piece is connected to the pole;

[0025] The edge of the chassis is constructed as a step structure, a step hole is formed on the connecting piece, and the step structure matches the step hole.

[0026] As an optional solution, the cover plate assembly includes an upper plastic part and a cover plate, the upper plastic part is arranged between the cover plate and the pressing block, and the pole passes through the cover plate and the upper plastic part in sequence and then is matched and connected with the pressing block.

[0027] As an optional solution, a venting groove is provided on a side of the upper plastic part abutting against the pressing block, and the venting groove is communicated with the mounting hole.

[0028] As an optional solution, a receiving groove is formed on a side of the upper plastic part close to the pressing block, a protrusion is formed on a side wall of the receiving groove, the pressing block is arranged in the receiving groove, and the protrusion abuts against the pressing block.

[0029] As an optional solution, a through hole for the pole to pass through is opened on the cover plate, and one end of the upper plastic part is inserted into the gap between the pole and the side wall of the through hole.

[0030] As an optional solution, the battery top cover further includes a sealing member, which is sleeved on the pole and used to seal between the pole and the cover plate.

[0031] A power battery comprises a shell, a battery cell and a battery top cover as described in any one of the above items, wherein the battery cell is arranged in the shell, and the battery top cover is buckled on the open end of the shell.

[0032] The assembly process of the battery top cover is used to assemble the battery top cover described in any one of the above items, and the specific steps include:

[0033] Step S1: putting a seal on the pole;

[0034] Step S2: passing the electrode with the seal installed through the cover plate assembly and fitting it with the mounting hole of the pressing block;

[0035] Step S3: applying pressure to the top of the pole by a jig to make the material on the top of the pole flow around, so that the pole, the pressing block and the cover plate assembly fit tightly together;

[0036] Step S4: The pressing block and the pole are fixedly connected by welding.

[0037] As an optional solution, the cover plate assembly includes an upper plastic part, a cover plate and a lower plastic part stacked in sequence, and the step S2 specifically includes:

[0038] Step S21: placing the lower plastic part under the cover plate, and passing the pole with the seal member mounted thereon through the lower plastic part and the cover plate in sequence;

[0039] Step S22: placing the upper plastic part on the cover plate and sleeved on the pole;

[0040] Step S23: placing the pressing block on the upper plastic part and sleeved on the pole.

[0041] The beneficial effects of the present invention are:

[0042] The battery top cover provided by the present invention has a pole that passes through the cover plate assembly and is matched with the mounting hole. By applying pressure to the entire battery top cover, the components are closely fitted, and then the pressing block is connected and fixed to the pole through a welding process, so that the entire battery top cover becomes a whole, the connection is stable, the 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. The welding groove is used to accommodate the welding molten part to prevent the welding molten part from protruding from the upper surface of the pressing block, thereby ensuring the appearance flatness and aesthetics of the battery top cover.

[0043] The power battery provided by the present invention improves assembly efficiency and reduces costs by providing the battery top cover, while also ensuring the structural strength and connection strength of the battery top cover.

[0044] The battery top cover assembly process provided by the present invention is used to assemble the above-mentioned battery top cover, has high assembly efficiency, reduces costs, and can also ensure the structural strength of the battery top cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly and easily, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 is a schematic structural diagram of a battery top cover provided in Embodiment 1 of the present invention;

[0047] Figure 2is an exploded view of a battery top cover provided in Embodiment 1 of the present invention;

[0048] Figure 3 is a top view of a battery top cover provided in Embodiment 1 of the present invention;

[0049] Figure 4 yes Figure 3 Sectional view at AA in the middle;

[0050] Figure 5 yes Figure 4 A partial enlarged view of point B in the middle;

[0051] Figure 6 is a schematic diagram of the structure of a pole provided in the first embodiment of the present invention;

[0052] Figure 7 is an axial cross-sectional view of a pole provided in Embodiment 1 of the present invention;

[0053] Figure 8 is a schematic diagram of the structure of a pressing block provided in Embodiment 1 of the present invention;

[0054] Fig. 9 is a schematic structural diagram of an upper plastic part provided in Embodiment 1 of the present invention;

[0055] Fig.10 is a schematic diagram of the structure of a pole provided in the second embodiment of the present invention;

[0056] Fig.11 is a top view of a battery top cover provided in Embodiment 2 of the present invention;

[0057] Fig.12 yes Fig.11 Sectional view at CC;

[0058] Fig.13 yes Fig.12 A partial enlarged view of point D in the middle;

[0059] Fig.14 is a specific flow chart of the assembly process of the battery top cover provided in the first embodiment of the present invention;

[0060] Fig.15 It is a specific flow chart of step S2 provided in the first embodiment of the present invention.

[0061] In the figure:

[0062] 1. Cover plate assembly; 11. Upper plastic part; 111. Accommodation groove; 112. Exhaust groove; 113. Bump; 12. Cover plate; 121. Explosion-proof valve hole; 13. Lower plastic part;

[0063] 2. Pole; 21. Chassis; 211. Second groove; 212. Step surface; 22. Pole body; 221. First groove; 23. Lower cylinder; 24. Upper cylinder; 241. Positioning groove;

[0064] 3. Press block; 31. Mounting hole; 32. Welding groove;

[0065] 4. Seals;

[0066] 5. Connecting piece; 51. Step hole;

[0067] 6. Explosion-proof valve assembly; 61. Explosion-proof disk; 62. Explosion-proof disk film. DETAILED DESCRIPTION

[0068] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0069] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0071] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0072] Embodiment 1

[0073] This embodiment provides a power battery, which is a square battery, including a shell, a battery cell and a battery cover, wherein the battery cell is arranged in the shell, and the battery cover is buckled at the open end of the shell. The shell is used to carry the battery cell and provide effective restraint and protection for the battery cell. The shell can be made of a conductive metal material, such as aluminum, aluminum alloy, etc., and the battery cover can be sealed and connected to the shell by welding.

[0074] Specifically, Figure 1 and Figure 2 As shown, the battery top cover includes a cover plate assembly 1, a pole 2, a pressing block 3 and a sealing member 4. The pole 2 and the pressing block 3 are respectively arranged 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 in sequence from top to bottom. The pressing block 3 is arranged 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 pole 2 to pass through. A mounting hole 31 is formed on the pressing block 3. The cover plate 12 of this embodiment is a plain aluminum sheet. The pole 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 in sequence and then is matched and connected with the mounting hole 31 of the pressing block 3. The pole 2 and the pressing block 3 are fixed by laser welding. The pressing block 3 is pressed against the upper surface of the cover plate assembly 1, and the pole 2 is pressed against the lower surface of the cover plate assembly 1. The sealing member 4 is sleeved on the pole 2 to seal the pole 2 and the cover plate 12 .

[0075] refer to Figure 2 , the assembly process of the battery top cover is as follows: first, the sealing member 4 is sleeved on the upper part of the pole 2, and then the lower plastic member 13 is placed under the cover plate 12, and the pole 2 with the sealing member 4 is sequentially passed through the lower plastic member 13 and the cover plate 12, so that the bottom plate 21 at the bottom of the pole 2 abuts against the lower surface of the lower plastic member 13, and then the upper plastic member 11 is placed on the upper part of the cover plate 12 and sleeved on the pole 2, and then the pressing block 3 is placed on the upper plastic member 11 and sleeved on the pole 2, and then pressure is applied to the top of the pole 2 by a jig, so that the material at the top of the pole 2 flows around, so that the various components are closely fitted, and then the pressing block 3 is connected and fixed to the pole 2 by a laser welding process, so that the various component assemblies are fixed as a whole, and the connection is firm. 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.

[0076] It should be noted that if Figures 3 to 5 As shown, the cover plate 12 is used as the main support member of the battery top cover to carry other components. Figure 5As shown, the upper plastic part 11 is embedded in the assembly gap between the pressing block 3 and the cover plate 12, and plays an insulating role, isolating the pressing block 3 from the cover plate 12, reducing the probability of external short circuit of the power battery, and improving the safety performance of the power battery. The lower plastic part 13 is located between the cover plate 12 and the chassis 21 of the pole 2, isolating the cover plate 12 from the chassis 21 of the pole 2, playing an insulating role, and reducing the probability of external short circuit of the battery.

[0077] Preferably, reference Figure 5 A through hole is provided on the cover plate 12 for the pole 2 to pass through. After the pole 2 is inserted into the through hole of the cover plate 12, there is a little gap between the pole 2 and the side wall of the through hole. After the upper plastic part 11 is sleeved on the pole 2, the bottom end of the upper plastic part 11 is inserted into the gap between the pole 2 and the side wall of the through hole, thereby facilitating the positioning and installation of the upper plastic part 11 and making the operation more convenient.

[0078] Further, refer to Figure 5 The seal 4 is constructed as an annular step structure, and a portion with a smaller outer diameter is embedded in the assembly gap between the side wall of the through hole of the cover plate 12 and the pole 2, and abuts against the portion of the upper plastic part 11 inserted into the through hole. The end face of the portion with a larger outer diameter abuts against the lower surface of the cover plate 12, which not only plays a sealing role, but also insulates the cover plate 12 and the pole 2. The seal 4 has a certain elasticity and is interference-fitted in the assembly gap between the cover plate 12 and the pole 2, which helps to improve the sealing of the overall structure, prevent air from entering the interior of the power battery, and prevent the electrolyte from leaking out. The seal 4 is made of an acid-, alkali-, and high-temperature resistant elastic material, such as fluororubber, which can resist electrolyte corrosion.

[0079] Furthermore, if Figure 5 and Figure 8As shown, a welding groove 32 is provided on the surface of the pressing block 3, and the welding groove 32 is connected to the peripheral side of the mounting hole 31, and the welding groove 32 is used to accommodate the welding molten residue. Specifically, the upper surface of the pressing block 3 is arranged higher than the upper surface of the pole 2, and the welding groove 32 is circular. The welding groove 32 is located above the mounting hole 31 and is coaxially arranged with the mounting hole 31. The radial dimension of the welding groove 32 is larger than the radial dimension of the mounting hole 31, thereby forming a step structure at the top of the pressing block 3. It can be understood that when welding the pressing block 3 and the pole 2, welding will be performed at the top of the pressing block 3 along the junction of the pole 2 and the pressing block 3, so that the aluminum material on the top of the pole 2 will be extruded to form a welding molten residue during welding. The welding groove 32 is used to accommodate the welding molten residue extruded by welding, and prevent the welding molten residue from protruding from the upper surface of the pressing block 3, thereby ensuring the appearance flatness and aesthetics of the battery top cover. In other embodiments, the shape of the welding groove 32 may also be square, oval or other special shapes, 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.

[0080] like Figure 5 As shown, the pressing block 3 is provided with a chamfer on one side away from the welding groove 32 and at the edge of the mounting hole 31. When the pressing block 3 is sleeved on the pole 2, the chamfer can play a guiding role, thereby facilitating the insertion of the pole 2 into the mounting hole 31.

[0081] like Figure 2 As shown, specifically, the number of poles 2 is set to two, which are divided into a negative pole and a positive pole. The negative pole and the positive pole are used to conduct with external electrical components to achieve the conduction of current. Correspondingly, the number of the pressing block 3, the upper plastic part 11 and the sealing part 4 are each set to two to match the corresponding poles 2 respectively.

[0082] Furthermore, if Figure 5 As shown, the battery top cover also includes a connecting piece 5, which is arranged on the side of the lower plastic part 13 away from the cover plate 12. The number of connecting pieces 5 is set to two, namely a positive connecting piece and a negative connecting piece. The connecting piece 5 is constructed as a bending structure. One end of the positive connecting piece is used to be fixedly connected to the bottom of the positive pole column, and the other end is used to be connected to the positive ear of the battery cell. One end of the negative connecting piece is used to be connected to the bottom of the negative pole column, and the other end is used to be connected to the negative ear of the battery cell, so as to achieve current conduction. It should be noted that since the positive connecting piece needs to be welded and fixed to the aluminum positive ear, the positive connecting piece is preferably made of aluminum, and the negative connecting piece needs to be welded and fixed to the copper negative ear, so the negative connecting piece is preferably made of copper.

[0083] Furthermore, combined with Figure 5 and Figure 6In this embodiment, the pole 2 is a cap-shaped structure, which includes a coaxially arranged chassis 21 and a pole body 22 with decreasing outer edge sizes. The chassis 21 is pressed against the lower surface of the cover plate 12 to form a limit, and the pole body 22 cooperates with the mounting hole 31. Among them, the chassis 21 and the pole body 22 are both cylindrical structures, and the outer diameter of the chassis 21 is larger than the outer diameter of the pole body 22, so that after the pole body 22 is penetrated by the cover plate assembly 1, the chassis 21 can be in contact with the lower surface of the cover plate 12 to form a limit. In other embodiments, the chassis 21 and the pole body 22 can also be square, oval or other special shapes, as long as the outer edge size of the chassis 21 can be larger than the outer edge size of the pole body 22, and no specific limitation is made here.

[0084] Preferably, the pole 2 is an integrally formed structure, thereby improving the structural strength of the pole 2. At the same time, there is no need to assemble the chassis 21 and the pole body 22, simplifying the assembly process. Specifically, the negative pole is integrally formed by a copper-aluminum composite plate through a cold heading process, and the positive pole is integrally formed by an aluminum plate through a cold heading process. It is understandable that one end of the positive pole needs to be welded and fixed to the aluminum positive electrode connecting piece, so the positive pole can be made of pure aluminum plate. One end of the negative pole needs to be welded and fixed to the copper negative electrode connecting piece, so the negative pole is made of a copper-aluminum composite plate, the upper half close to the pole body 22 is made of aluminum, and the lower half close to the chassis 21 is made of copper, which is used to be welded and fixed to the copper negative electrode connecting piece. By cold heading the negative pole with a copper-aluminum composite plate, the process of friction welding connection of the traditional negative pole is eliminated, saving costs. Due to the use of copper-aluminum composite plates, the amount of copper is also reduced, reducing the weight of the battery top cover.

[0085] Furthermore, if Figure 2 and Figure 7 As shown, the axis of the pole 2 is perpendicular to the lower plastic part 13, and the outer wall of the pole 2 is inclined relative to the axis of the pole 2, the hole wall of the mounting hole 31 and the outer wall of the pole 2 have the same inclination direction and inclination angle, and the outer wall of the pole 2 fits the hole wall of the mounting hole 31. The outer wall of the pole 2 here specifically refers to the outer wall of the pole body 22, and does not include the outer wall of the chassis 21. In this embodiment, as Figure 7As shown, the outer wall of the pole 2 is inclined from bottom to top toward the inside of the pole 2. In other embodiments, the outer wall of the pole 2 can also be inclined from bottom to top toward the direction away from the pole 2, and the hole wall of the mounting hole 31 can be set to the same inclination direction and inclination angle. In other words, the outer wall of the pole body 22 is an inclined surface, and the hole wall of the mounting hole 31 is also an inclined surface, so that the pole 2 and the mounting hole 31 are matched through the inclined surface. On the one hand, the setting of the inclined surface prevents the lower plastic part 13 from being burned by direct laser during laser welding. On the other hand, the joint surface between the pole body 22 and the pressing block 3 can form an interlocking through the inclined surface, thereby improving the structural strength of the battery cover.

[0086] Alternatively, if Figure 7 As shown, the angle θ between the outer wall of the pole 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 hole 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 pole body 22 and the inclination angle of the hole wall of the mounting hole 31 within the above range, it is not only possible to prevent the laser from directly irradiating during laser welding and burning the lower plastic part 13, but also to form an interlocking at the joint surface of the pole body 22 and the pressing block 3, thereby improving the structural strength of the battery cover.

[0087] Furthermore, if Figure 6 and Figure 7 As shown, a first groove 221 is provided at the top of the pole body 22. First, the provision of the first groove 221 can achieve the effect of weight reduction, thereby reducing the weight of the battery top cover and realizing a lightweight design. Secondly, since the pole 2 is made by a cold heading process, the cold heading process deforms the blank by cold extrusion to form the pole 2. By extruding the first groove 221 at the top of the pole body 22, the material at the first groove 221 can be moved to the pole body 22 on both sides, thereby increasing the height of the pole body 22 to meet the design size requirements. Among them, the shape of the first groove 221 can be but is not limited to circular, square, elliptical or other special shapes, and can be flexibly set according to needs, and no specific limitation is made here.

[0088] Preferably, if Figure 7 As shown, 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 2 mm. Exemplarily, the minimum distance W is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm or 7 mm. The minimum distance W is also the minimum wall thickness of the pole body 22. By setting the minimum wall thickness of the pole body 22 within the above range, the pole 2 can ensure structural strength to meet the welding strength, thereby ensuring the structural strength of the battery top cover.

[0089] Furthermore, if Figure 7 As shown, a second groove 211 is formed at the bottom of the chassis 21. First, by extruding the second groove 211 at the bottom of the chassis 21, the material at the second groove 211 can be moved to the chassis 21 on both sides during the extrusion process, so that the diameter of the chassis 21 can be larger, and the size around the second groove 211 can be fuller to meet the size requirements. Secondly, since the negative pole is made of a copper-aluminum composite plate through a cold heading process, during the extrusion of the billet, due to the different hardness of the copper and aluminum materials (the hardness of copper is greater than that of aluminum), the copper material will squeeze the aluminum material, so that a wavy joint surface is easily formed at the joint of the copper and aluminum materials, thereby affecting the structural strength of the negative pole. By extruding the second groove 211 at the bottom of the chassis 21, the copper-aluminum composite plate provides a flow space for the copper material during the isovolumetric deformation process, reduces the extrusion of the copper material on the aluminum material, and makes the joint surface of the copper and aluminum materials smoother, thereby ensuring the structural strength of the negative pole, so that the root of the negative pole is not easy to break. The shape of the second groove 211 may be, but is not limited to, circular, square, elliptical or other special shapes, and may be flexibly set according to requirements, and no specific limitation is made here.

[0090] Preferably, if Figure 7 As shown, the axial cross section of the second groove 211 is arched, and the angle α between the circumferential side wall 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 side wall of the second groove 211 within the above range, the copper material in the copper-aluminum composite plate can be provided with better fluidity, so that the root of the negative pole is not easy to break during the integral molding process, thereby ensuring the structural strength of the negative pole.

[0091] Furthermore, if Fig. 9 As shown, the upper plastic part 11 is provided with an exhaust groove 112 on one side of the pressing block 3, and the exhaust groove 112 is connected to the mounting hole 31. After the bottom surface of the pressing block 3 is attached to the surface of the upper plastic part 11, there is a certain gap between the exhaust groove 112 and the pressing block 3. The exhaust groove 112 can discharge the hot gas generated during the welding process to prevent the deformation of the pole 2 or the pressing block 3 caused by the inability to discharge the hot gas during the welding process. Among them, the shape of the exhaust groove 112 is set to be an annular groove plus four straight grooves connected to the annular groove. In other embodiments, the exhaust groove 112 can also be other shapes, which can be flexibly set according to needs, and no specific limitation is made here.

[0092] Preferably, if Fig. 9As shown, a receiving groove 111 is provided on one side of the upper plastic part 11 close to the pressing block 3. The pressing block 3 is arranged in the receiving groove 111, so as to limit the pressing block 3. The exhaust groove 112 is arranged at the bottom of the receiving groove 111. After the pressing block 3 is placed in the receiving groove 111, the bottom surface of the pressing block 3 is in contact with the bottom surface of the receiving groove 111. A plurality of protrusions 113 arranged at intervals along the circumference of the receiving groove 111 are formed on the side wall of the receiving groove 111. The thickness of the protrusions 113 is very thin, and the protrusions 113 abut against the pressing block 3. When the pressing block 3 is placed in the receiving groove 111, the protrusions 113 can locate the position of the pressing block 3. The surface of the protrusions 113 can be set as an inclined surface, so that the pressing block 3 can enter the receiving groove 111 along the surface of the protrusions 113, and the operation is more convenient. The specific number of the protrusions 113 is not specifically limited here, and can be flexibly set according to actual needs.

[0093] Further, refer to Figure 2 , Figure 5 and Figure 7 , the edge of the chassis 21 is constructed as a step structure, a step hole 51 is formed on the connecting piece 5, and the step structure matches the step hole 51. Specifically, the step structure enables the chassis 21 to have two sections of different outer diameters, and a step surface 212 is formed on the step structure, and the step hole 51 also includes two sections of holes with different diameters. When the chassis 21 is matched with the connecting piece 5, the part with a smaller outer diameter in the chassis 21 is inserted into the hole with a smaller diameter in the step hole 51, and the part with a larger outer diameter in the chassis 21 matches with the hole with a larger diameter in the step hole 51, and the step surface 212 of the chassis 21 matches with the step surface of the step 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 limited after assembly, so as to facilitate the subsequent assembly and welding process.

[0094] Furthermore, if Figure 1 and Figure 2 As shown, the battery top cover also includes an explosion-proof valve assembly 6, which includes an explosion-proof disc 61 and an explosion-proof disc film 62. The explosion-proof disc 61 is assembled in the explosion-proof valve hole 121 of the cover plate 12 by welding. The explosion-proof disc 61 can automatically and quickly release the pressure of the battery when the internal pressure of the battery rises, thereby avoiding the occurrence of safety accidents caused by the explosion of the power battery. The explosion-proof disc film 62 plays a role in protecting the explosion-proof disc 61 and preventing external dust, water or other impurities from entering the explosion-proof disc 61.

[0095] like Fig.14 and Fig.15 As shown, this embodiment also provides a battery top cover assembly process for assembling the above-mentioned battery top cover, referring to Figure 2 , the specific steps include:

[0096] Step S1: putting the sealing member 4 on the pole 2;

[0097] Step S2: the pole 2 with the seal 4 installed passes through the cover plate assembly 1 and matches with the mounting hole 31 of the pressing block 3;

[0098] Step S3: applying pressure to the top of the pole 2 by means of a jig, so that the material on the top of the pole 2 flows to the surroundings, so that the pole 2, the pressing block 3 and the cover plate assembly 1 are closely fitted;

[0099] Step S4: The pressing block 3 and the pole 2 are fixedly connected by welding.

[0100] Wherein, step S2 specifically includes:

[0101] Step S21: Place the lower plastic part 13 below the cover plate 12, and pass the pole 2 with the seal 4 through the lower plastic part 13 and the cover plate 12 in sequence. After this step, the bottom plate 21 of the pole 2 abuts against the lower surface of the lower plastic part 13.

[0102] Step S22: placing the upper plastic part 11 on the cover plate 12 and sleeved on the pole 2;

[0103] Step S23 : placing the pressing block 3 on the upper plastic component 11 and sleeved on the pole 2 .

[0104] It should be noted that, by applying pressure to the top of the pole 2 through the jig, the material on the top of the pole 2 flows around, so that the pole 2, the pressing block 3, the upper plastic part 11, the cover plate 12, the lower plastic part 13 and the seal 4 are tightly fitted, and then the pressing block 3 is connected and fixed to the pole 2 through the laser welding process, so that the various components are fixed as a whole, and the connection is firm. Compared with the riveted top cover, the welding process is simple and the cost is low, which improves the assembly efficiency of the battery top cover and can also ensure the connection strength and structural strength of the battery top cover.

[0105] Embodiment 2

[0106] The specific structure of the battery top cover provided in this embodiment is substantially the same as that of the battery top cover provided in the first embodiment, and the similarities are not repeated here. The differences are as follows:

[0107] like Figures 10 to 13As shown, in this embodiment, the pole 2 is also integrally formed by a cold heading process. Specifically, the pole 2 is a tower-shaped structure, which includes a coaxially arranged chassis 21, a lower cylinder 23 and an upper cylinder 24 with decreasing outer edge sizes. The chassis 21 is pressed against the side surface of the lower plastic part 13 away from the pressing block 3, the lower cylinder 23 penetrates the cover plate assembly 1 and abuts against the lower surface of the pressing block 3, and the upper cylinder 24 cooperates with the mounting hole 31, that is, the outer wall of the upper cylinder 24 is arranged in a close contact with the hole wall of the mounting hole 31. By setting the pole 2 as a tower-shaped structure with decreasing outer diameters, based on the isovolumetric deformation of the cold heading process, the height of the pole 2 can be raised to meet the design size requirements. Among them, the chassis 21 and the upper cylinder 24 are both cylindrical structures. In other embodiments, the chassis 21, the lower cylinder 23 and the upper cylinder 24 can also be square, elliptical or other special shapes, as long as the outer edge size can be guaranteed to decrease in sequence, and no specific limitation is made here.

[0108] Preferably, if Fig.10 As shown, a positioning groove 241 is provided on the top of the upper column 24, and the positioning groove 241 is used for inserting and positioning an external pressure fixture during welding. The shape of the positioning groove 241 can be, but is not limited to, circular, square, oval or other special shapes, and can be flexibly set according to needs, and no specific limitation is made here.

[0109] It should be noted that the pole 2 provided in this embodiment can also be applied to the riveting process, in which case the positioning groove 241 is used for positioning and inserting the riveting jig. Fig.13 As shown, when the pole 2 and the pressing block 3 are assembled, the riveting jig will be inserted into the positioning groove 241 to squeeze the inside of the positioning groove 241 to laterally squeeze and deform the end of the pole 2, and the top of the pole 2 is filled with the material above the pressing block 3. At the same time, the pressing block 3 in contact with the riveting jig will also be squeezed and deformed, and the material of the pressing block 3 is filled with the position between the upper column 24 and the lower column 23, so that the pressing block 3 and the pole 2 are buckled, and finally formed as shown. Fig.13 The riveted structure shown is then welded to the upper column 24 and the pressing block 3, so that the pole 2 and the pressing block 3 are more tightly combined, ensuring that the overall structure of the battery top cover is more stable.

[0110] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery cover, characterized in that: include: Cover plate assembly (1); A pole (2) and a pressing block (3), wherein a mounting hole (31) is formed on the pressing block (3), and the pole (2) is matched with the mounting hole (31) after passing through the cover plate assembly (1), and a welding groove (32) is opened on the surface of the pressing block (3), and the welding groove (32) is connected to the peripheral side of the mounting hole (31), the pole (2) and the pressing block (3) are fixed by welding, and the welding groove (32) is used to accommodate the welding molten part, and the pressing block (3) and the pole (2) are respectively pressed against the two sides of the cover plate assembly (1).

2. The battery top cover according to claim 1, characterized in that: The cover plate assembly (1) comprises a stacked cover plate (12) and a lower plastic part (13); the pressing block (3) is arranged on a side of the cover plate (12) away from the lower plastic part (13); the axis of the pole (2) is perpendicular to the lower plastic part (13); and the outer side wall of the pole (2) is arranged at an inclination relative to the axis of the pole (2).

3. The battery top cover according to claim 2, characterized in that: The inclination direction and inclination angle of the hole wall of the mounting hole (31) and the outer wall of the pole (2) are the same, and the outer wall of the pole (2) fits closely with the hole wall of the mounting hole (31).

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

5. The battery top cover according to claim 1, characterized in that: The upper surface of the pressing block (3) is arranged higher than the upper surface of the pole (2), the welding groove (32) is located above the mounting hole (31) and is coaxially arranged 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).

6. The battery top cover according to claim 1, characterized in that: The pole (2) is divided into a negative pole and a positive pole. The negative pole is integrally formed from a copper-aluminum composite plate by a cold heading process, and the positive pole is integrally formed from an aluminum plate by a cold heading process.

7. The battery top cover according to claim 1, characterized in that: The pole (2) comprises a coaxially arranged chassis (21) and a pole body (22) with outer edge sizes decreasing successively; the chassis (21) is pressed against the surface of the cover plate assembly (1), and the pole body (22) cooperates with the mounting hole (31).

8. The battery top cover according to claim 7, characterized in that: A first groove (221) is formed on the top of the pole body (22).

9. The battery top cover according to claim 8, characterized in that: 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 2 mm.

10. The battery top cover according to claim 1, characterized in that: The pole (2) comprises a chassis (21), a lower column (23) and an upper column (24) which are coaxially arranged and have outer edge sizes decreasing in sequence; the chassis (21) is pressed against a surface of the cover plate assembly (1) which is away from the pressing block (3); the lower column (23) passes through the cover plate assembly (1) and is in contact with the surface of the pressing block (3); and the upper column (24) cooperates with the mounting hole (31).

11. The battery top cover according to claim 10, characterized in that: A positioning groove (241) is provided on the top of the upper column (24), and the positioning groove (241) is used for inserting an external fixture.

12. The battery top cover according to any one of claims 7 to 11, characterized in that: A second groove (211) is formed at the bottom of the bottom plate (21).

13. The battery top cover according to claim 12, characterized in that: The axial cross section of the second groove (211) is arched, and the angle α between its circumferential side wall and the horizontal plane is greater than or equal to 15° and less than or equal to 60°.

14. The battery top cover according to any one of claims 7 to 11, characterized in that: A chamfer is provided on the side of the pressing block (3) facing away from the welding groove (32) and at the edge of the mounting hole (31).

15. The battery top cover according to any one of claims 7 to 11, characterized in that: The battery top cover also includes a connecting piece (5), the connecting piece (5) is used to be connected to the pole ear of the battery cell, and the connecting piece (5) is connected to the pole (2); The edge of the chassis (21) is constructed as a step structure, a step hole (51) is formed on the connecting piece (5), and the step structure matches the step hole (51).

16. The battery top cover according to claim 1, characterized in that: The cover plate assembly (1) comprises an upper plastic part (11) and a cover plate (12); the upper plastic part (11) is arranged between the cover plate (12) and the pressing block (3); the pole (2) passes through the cover plate (12) and the upper plastic part (11) in sequence and then is matched and connected with the pressing block (3).

17. The battery top cover according to claim 16, characterized in that: An exhaust groove (112) is provided on one side of the upper plastic part (11) abutting against the pressing block (3), and the exhaust groove (112) is communicated with the mounting hole (31).

18. The battery top cover according to claim 16, characterized in that: A receiving groove (111) is provided on one side of the upper plastic part (11) close to the pressing block (3), a protrusion (113) is formed on the side wall of the receiving groove (111), the pressing block (3) is arranged in the receiving groove (111), and the protrusion (113) abuts against the pressing block (3).

19. The battery top cover according to claim 16, characterized in that: The cover plate (12) is provided with a through hole for the pole (2) to pass through, and one end of the upper plastic part (11) is inserted into the gap between the pole (2) and the side wall of the through hole.

20. The battery top cover according to claim 16, characterized in that: The battery top cover also includes a sealing member (4), which is sleeved on the pole (2) and is used to seal between the pole (2) and the cover plate (12).

21. A power battery, characterized in that: It comprises a shell, a battery cell and a battery top cover as described in any one of claims 1 to 20, wherein the battery cell is arranged in the shell, and the battery top cover is buckled on the open end of the shell.

22. A battery top cover assembly process, used for assembling the battery top cover as claimed in any one of claims 1 to 20, characterized in that: The specific steps include: Step S1: fitting the sealing member (4) onto the pole (2); Step S2: passing the pole (2) with the sealing member (4) mounted thereon through the cover plate assembly (1) and engaging the pole with the mounting hole (31) of the pressing block (3); Step S3: applying pressure to the top of the pole (2) by means of a jig, so that the material on the top of the pole (2) flows around, so that the pole (2), the pressing block (3) and the cover plate assembly (1) are closely fitted; Step S4: The pressing block (3) and the pole (2) are fixedly connected by a welding process.

23. The battery top cover assembly process according to claim 22, characterized in that: The cover plate assembly (1) comprises an upper plastic part (11), a cover plate (12) and a lower plastic part (13) stacked in sequence, and the step S2 specifically comprises: step S21: placing the lower plastic part (13) below the cover plate (12), and passing the pole (2) with the sealing member (4) mounted thereon through the lower plastic part (13) and the cover plate (12) in sequence; Step S22: placing the upper plastic part (11) on the cover plate (12) and sleeved on the pole (2); Step S23: placing the pressing block (3) above the upper plastic part (11) and sleeved on the pole (2).

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