Cover plate assembly of large cylindrical battery and large cylindrical battery

Abstract

The application provides a cover plate assembly of a large cylindrical battery and the large cylindrical battery. A welding groove of a bus bar is used for welding with an end surface of an electric core. An end of a connecting piece away from the bus bar is bent and welded and fixed with a welding part. A fixed part passes through a containing hole and a through hole and is riveted to fix the cover plate body and a pole. An insulation assembly is located between the cover plate body and a riveting block or between the cover plate body and the pole. The application can increase the current-carrying area by optimizing the pole connection mode and the integrated structure design of the bus disc, effectively solves the problem of uneven current distribution when the large-diameter electric core tab is connected, has compact structure, high safety and reliability, is beneficial to the electrolyte infiltration of the electric core, has low impedance and high current distribution characteristics, can comprehensively improve the intrinsic safety level and electrochemical performance of the battery, can effectively reduce the risk of internal thermal runaway of the battery, and improves the group efficiency and cycle life of the large cylindrical battery.

Description

[Technical Field] This invention relates to the field of battery technology, and in particular to a cover plate assembly for a large cylindrical battery and the large cylindrical battery itself. [Background Technology] With the rapid development of the new energy vehicle industry and new energy storage systems, the energy density and safety of power batteries have become core bottlenecks restricting the industry's progress. Large cylindrical lithium-ion batteries (such as cylindrical batteries with a diameter of 32mm and above) have gradually become a research hotspot and application trend in the field of power batteries due to their significant advantages such as large single-cell capacity, simple structure, excellent heat dissipation performance, and ease of large-scale automated production.

[0003] In existing large cylindrical battery cover structures, traditional single-pole or simple parallel pole structures are used. When facing high-current charging and discharging, it is difficult to ensure the uniform distribution of current across the entire cover surface, which can easily lead to local overheating and exacerbate side reactions. Furthermore, the structural design of the busbar either focuses on current carrying capacity or electrolyte diffusion, and there are few structural solutions that combine the advantages of both. In addition, as the cover function becomes increasingly complex and the number of components increases, the overall height increases, reducing the volumetric energy density of the battery. Moreover, the complex assembly process also increases manufacturing costs and the risk of failure.

[0004] Therefore, it is necessary to provide a novel cover plate assembly for a large cylindrical battery and a large cylindrical battery to overcome the above-mentioned defects. [Summary of the Invention] The purpose of this invention is to provide a cover plate assembly for a large cylindrical battery and a large cylindrical battery to overcome the above-mentioned technical problems.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a cover plate assembly for a large cylindrical battery, comprising an integrated busbar, a riveting block, a cover plate body, terminals, and an insulating component; the integrated busbar includes a busbar segment and a connecting piece extending from the busbar segment, the busbar segment having a through-hole at its center, and the busbar segment also having a plurality of weld grooves and flow holes located around the center hole; the riveting block includes a welding portion and a fixing portion located on the welding portion, the cover plate body having a through-hole at its center, and the terminals having through holes; the weld grooves of the busbar segment are used for welding to the end face of the battery cell, the end of the connecting piece away from the busbar segment is bent and welded to the welding portion for fixation, the fixing portion passes through the through-hole and the receiving hole and is riveted to fix the cover plate body and the terminals, and the insulating component is located between the cover plate body and the riveting block or between the cover plate body and the terminals.

[0007] In a preferred embodiment, the insulating component includes a lower insulating pad with a first through hole at its center. The lower insulating pad is located between the welding portion and the cover plate body, and the fixing portion passes through the first through hole.

[0008] In a preferred embodiment, the insulating assembly further includes an upper insulating pad with a second through hole at its center, through which the fixing part passes; a first receiving groove is formed on the surface of the cover plate body away from the connecting piece, the first receiving groove communicating with the receiving hole, the upper insulating pad being received in the first receiving groove, and a second receiving groove is formed on the surface of the upper insulating pad away from the cover plate body, with the pole being received in the second receiving groove; the insulating assembly further includes a sealing ring fitted on the fixing part.

[0009] In a preferred embodiment, the cover plate body is further provided with a through first explosion-proof hole, the first explosion-proof hole is located around the receiving hole, the first explosion-proof hole contains an explosion-proof sheet, the explosion-proof sheet is stamped with explosion-proof markings, and the explosion-proof sheet is covered with a protective sheet.

[0010] In a preferred embodiment, the lower insulating pad has a second explosion-proof hole, which is positioned opposite to the first explosion-proof hole, and a first partition connecting the edge of the second explosion-proof hole is provided inside the second explosion-proof hole.

[0011] In a preferred embodiment, the cover plate body is further provided with a through first injection hole, which is located around the receiving hole; the lower insulating pad is provided with a second injection hole, which is opposite to the first injection hole, and a second partition connecting the edge of the second injection hole is provided inside the second injection hole.

[0012] In a preferred embodiment, there are two weld grooves, which are symmetrically arranged on both sides of the central hole. The flow hole includes a side hole. The two ends of the weld groove are connected to the edge of the manifold. The middle part of the weld groove is bent towards the central hole to form a curved part. The side hole is located on the side of the curved part away from the central hole.

[0013] In a preferred embodiment, the flow hole further includes an end hole located between the two weld grooves.

[0014] In a preferred embodiment, the connecting piece is provided with reinforcing ribs, and / or the connecting piece is provided with channel holes.

[0015] In a second aspect, the present invention also provides a large cylindrical battery, including a casing, a battery cell, and a cover plate assembly for the large cylindrical battery as described in any one of the first aspects above. One end of the casing is open, the battery cell is housed within the casing, and the cover plate assembly for the large cylindrical battery is disposed at one end of the opening of the casing and welded to the end face of the battery cell.

[0016] Compared to existing technologies, the cover plate assembly and large cylindrical battery provided by this invention adopt an integrated busbar structure. The integrated busbar includes a busbar piece and a connecting piece extending from the busbar piece. The busbar piece has a through-hole in its center and also has several weld grooves and flow holes around the center hole. The riveting block includes a welding part and a fixing part located on the welding part. The cover plate body has a through-hole in its center and the terminal post has a through hole. The weld grooves of the busbar piece are used for welding to the end face of the battery cell. The end of the connecting piece away from the busbar piece is bent and welded to the welding part for fixation. The fixing part passes through the receiving hole and the through hole and is riveted to fix the cover plate body and the terminal post. The insulating component is located between the cover plate body and the riveting block or between the cover plate body and the terminal post. This invention optimizes the electrode connection method and the integrated structure design of the busbar, thereby increasing the current-carrying area and effectively solving the problem of uneven current distribution when connecting large-diameter cells. The structure is compact, safe and reliable, and facilitates electrolyte wetting of the cells. It has low impedance and high current-equalization characteristics, which can comprehensively improve the intrinsic safety level and electrochemical performance of the battery. It can also effectively reduce the risk of internal thermal runaway of the battery and improve the packing efficiency and cycle life of large cylindrical batteries. [Attached Image Description] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of the cover plate assembly of the large cylindrical battery provided in Embodiment 1 of the present invention.

[0019] Figure 2 for Figure 1 The diagram shows the structure of the integrated busbar in the cover assembly of the large cylindrical battery.

[0020] Figure 3 This is a structural diagram of an integrated busbar provided for another embodiment of the present invention.

[0021] Figure 4 This is a structural diagram of the cover plate assembly provided in Embodiment 2 of the present invention.

[0022] Figure 5 This is a structural diagram of the cover plate assembly provided in Embodiment 3 of the present invention.

[0023] Figure 6 This is a structural diagram of the cover plate assembly provided in Embodiment 4 of the present invention.

[0024] Figures 7 to 10 The diagram shows the structure of the cover plate assembly provided in Embodiments 5 to 8 of the present invention.

[0025] Figures 11 to 14 This is a structural diagram of the cover plate assembly provided in Embodiments 9 to 12 of the present invention.

[0026] Figures 15 to 18 The diagram shows the structure of the cover plate assembly provided in Embodiments 13 to 16 of the present invention.

[0027] Figures 19 to 22 This is a structural diagram of the cover plate assembly provided in Embodiments 17 to 20 of the present invention.

[0028] Figures 23 to 26 The above are structural diagrams of the cover plate assemblies provided in Embodiments 21 to 24 of the present invention.

[0029] Figure 27 This is a structural diagram of a large cylindrical battery provided by the present invention.

[0030] Explanation of reference numerals in the attached drawings: 100 - Cover plate assembly for large cylindrical battery; 10 - Integrated busbar; 11 - Busbar piece; 111 - Center hole; 112 - Weld groove; 113 - Flow hole; 114 - Side hole; 115 - Bending part; 116 - End hole; 12 - Connecting piece; 121 - Reinforcing rib; 122 - Channel hole; 20 - Riveting block; 21 - Welding part; 22 - Fixing part; 30 - Cover plate body; 301 - Receiving hole; 302 - First receiving groove; 303 - First explosion-proof hole, 304 - First liquid injection hole, 31 - Explosion-proof sheet, 311 - Explosion-proof notch, 32 - Protective sheet; 40 - Terminal post, 401 - Through hole; 50 - Insulating component, 51 - Lower insulating pad, 511 - First through hole, 512 - Second explosion-proof hole, 513 - First partition, 514 - Second liquid injection hole, 515 - Second partition, 516 - Hollow hole, 52 - Upper insulating pad, 521 - Second through hole, 522 - Second receiving groove, 53 - Sealing ring. 200 - Large cylindrical battery, 201 - Casing, 202 - Cell.

Detailed Implementation Methods

[0032] Please see Figure 1 This is a structural diagram of the cover plate assembly of the large cylindrical battery provided in Embodiment 1 of the present invention. Please refer to it as well. Figure 27 The cover plate assembly 100 for a large cylindrical battery provided by the present invention can be applied to... Figure 27 Specifically, the cover assembly 100 of the large cylindrical battery 200 shown includes an integrated busbar 10, a rivet block 20, a cover body 30, a terminal post 40, and an insulation component 50.

[0033] The integrated busbar 10 includes a busbar 11 and a connecting piece 12 extending from the busbar 11. The busbar 11 has a through-hole 111 at its center. The busbar 11 is approximately circular, and the central hole 111 is located at its center, providing a channel for electrolyte to flow between the negative and positive terminals of the battery cell. The busbar 11 also has several welding grooves 112 and flow holes 113 around the central hole 111. The welding grooves 112 are used for welding to the battery cell end face, specifically the negative terminal face, and the flow holes 113 provide a channel for electrolyte flow. The connecting piece 12 is approximately elongated and is used for welding and fixing to the rivet block 20, further connecting to the terminal post 40, specifically the negative terminal post, thus leading out the battery's negative terminal. The terminal 40 is a cylindrical body that can serve as an external electrical connection terminal for the negative terminal of the battery, and outputs the electrical energy collected in the integrated busbar 10 to the external circuit.

[0034] Understandably, this embodiment uses the cover plate assembly as a negative electrode cover plate for example. That is, the busbar 11 is welded to the negative end face of the battery cell, the connecting piece 12 is welded and fixed to the riveting block 20, and further connected to the negative electrode post to lead out the negative electrode of the battery. In other embodiments, the cover plate assembly can also be a positive electrode cover plate assembly. The busbar 11 is welded to the positive end face of the battery cell, the connecting piece 12 is welded and fixed to the riveting block 20, and further connected to the positive electrode post to lead out the positive electrode of the battery. Its principle is similar to that of the negative electrode cover plate, and will not be described in detail in this invention.

[0035] The rivet block 20 includes a welding part 21 and a fixing part 22 located on the welding part 21. The cover plate body 30 has a through receiving hole 301 in the center, and the pole post 40 has a through hole 401.

[0036] The cover body 30 is specifically an aluminum disc with stepped edges, which can serve as the base for the entire cover assembly. It is sealed together with the battery casing by laser welding to achieve battery encapsulation.

[0037] The welding groove 112 of the busbar 11 is used for welding to the end face of the battery cell. The end of the connecting piece 12 away from the busbar 11 is bent and welded to the welding part 21 for fixation. The fixing part 22 passes through the receiving hole 301 and the through hole 401 and is riveted to fix the cover plate body 30 and the pole post 40. The insulating component 50 is located between the cover plate body 30 and the riveting block 20 or between the cover plate body 30 and the pole post 40. The insulating component 50 can ensure the insulation between the cover plate body 30 and the riveting block 20 and the pole post 40.

[0038] The insulating component 50 includes a lower insulating pad 51, with a first through hole 511 at its center. The lower insulating pad 51 is located between the welded part 21 and the cover plate body 30, and the fixing part 22 passes through the first through hole 511. The lower insulating pad 51 can isolate the welded part 21 from the cover plate body 30, ensuring the insulation between the cover plate body 30 and the rivet block 20 and preventing short circuits.

[0039] The insulating assembly 50 also includes an upper insulating pad 52, the upper insulating pad 52 having a second through hole 521 at its center, through which the fixing part 22 passes. A first receiving groove 302 is formed on the surface of the cover plate body 30 away from the connecting piece 12, the first receiving groove 302 communicating with the receiving hole 301. The upper insulating pad 52 is received within the first receiving groove 302. Specifically, a protrusion corresponding to the shape and size of the first receiving groove 302 can be provided on the surface of the upper insulating pad 52 near the cover plate body 30. The protrusion is engaged within the first receiving groove 302, achieving positioning and engagement between the two. A second receiving groove 522 is formed on the surface of the upper insulating pad 52 away from the cover plate body 30, and the electrode post 40 is received within the second receiving groove 522. The upper insulating pad 52 isolates the electrode post 40 from the cover plate body 30, ensuring insulation between the cover plate body 30 and the electrode post 40 and preventing short circuits.

[0040] Specifically, the upper insulating pad 52 is located above the cover plate body 30 and is a square plastic component. The protrusion under the upper insulating pad 52 is roughly square, and the first receiving groove 302 on the cover plate body 30 is also roughly square. The square protrusion is directly opposite the square first receiving groove 302 at the center of the cover plate body 30. The upper insulating pad 52 is also provided with a second receiving groove 522 for receiving the pole post 40. The upper insulating pad 52 can serve as a structural support for the pole post 40. The cover plate body 30 can simultaneously provide a base for the installation and positioning of the upper insulating pad 52 and the pole post 40, preventing displacement or shift when the negative pole post or the upper insulating pad is subjected to vibration or assembly stress.

[0041] Understandably, the present invention does not specifically limit the shape of the upper insulating pad 52, as long as it can satisfy the insulation and support functions.

[0042] The insulating component 50 also includes a sealing ring 53, which is fitted onto the fixing part 22. The sealing ring 53 isolates the fixing part 22 from the cover plate body 30, further ensuring the insulation between the cover plate body 30 and the rivet block 20 and preventing short circuits. Furthermore, the sealing ring 53 also further seals the receiving hole 301 of the cover plate body 30, ensuring the sealing of the connection between the cover plate body 30 and the rivet block 20.

[0043] Furthermore, the cover plate body 30 is also provided with a through first explosion-proof hole 303. The first explosion-proof hole 303 is located around the receiving hole 301. An explosion-proof sheet 31 is received in the first explosion-proof hole 303. The explosion-proof sheet 31 is stamped with explosion-proof markings 311. A protective sheet 32 ​​is covered on the explosion-proof sheet 31.

[0044] The lower insulating pad 51 has a second explosion-proof hole 512, which is opposite to the first explosion-proof hole 303. A first partition 513 connecting the edge of the second explosion-proof hole 512 is provided inside the second explosion-proof hole 512.

[0045] Specifically, the protective sheet 32 ​​is a small round sheet of PP or PET material with a central through hole, which covers the lower explosion-proof sheet 31 to prevent it from being damaged by external objects. The explosion-proof sheet 31 is a circular aluminum sheet with a thinner explosion-proof groove 311 stamped on a concentric circle near the edge of the circular aluminum sheet. Because of its thinner thickness, this thin circle is more easily punctured when subjected to internal battery pressure, thus achieving the function of internal gas depressurization. The explosion-proof sheet 31 is fixed to the first explosion-proof hole 303 on the cover plate body 30 by laser welding. The protective sheet 32, the explosion-proof sheet 31, and the first explosion-proof hole 303 together form an explosion-proof component. When the internal pressure of the battery rises abnormally, the explosion-proof sheet actively breaks open to release pressure, preventing the casing containing the battery cell from bursting and ensuring safety.

[0046] Furthermore, the cover plate body 30 also has a through first injection hole 304, which is located around the receiving hole 301. The lower insulating pad 51 has a second injection hole 514, which is opposite to the first injection hole 304. A second partition 515 connecting the edge of the second injection hole 514 is provided inside the second injection hole 514.

[0047] Understandably, the lower insulating pad 51 has a through hole corresponding to the rivet block 20, namely the first through hole 511, which is located in the center and is fully open. The lower insulating pad 51 also has a second injection hole 514 facing the first injection hole 304 and a second explosion-proof hole 512 facing the first explosion-proof hole 303. A second partition 515 connecting the edge of the second injection hole 514 is provided in the second injection hole 514. A first partition 513 connecting the edge of the second explosion-proof hole 512 is provided in the second explosion-proof hole 512. Specifically, the first partition 513 is a cross-shaped partition, and the second partition 515 is a central circular partition stacked with a cross-shaped partition around the central circular partition. The first partition 513 and the second partition 515 can enhance the structural stability of the lower insulating pad 51 at the second explosion-proof hole 512 and the second injection hole 514. In addition to providing electrical insulation, the lower insulating pad 51 also provides a channel for the flow of electrolyte and gas from the explosion-proof valve, and provides a physical mounting position for the rivet block that connects the internal and external current channels. Its core function is to prevent the central negative electrode post from directly contacting the outer aluminum cover plate body and causing a short circuit.

[0048] In this embodiment, both the first explosion-proof hole 303 and the first liquid injection hole 304 are circular holes. The centers of the first explosion-proof hole 303, the first liquid injection hole 304, and the receiving hole 301 are on the same straight line. That is, the first explosion-proof hole 303 and the first liquid injection hole 304 are located on opposite sides of the receiving hole 301. Correspondingly, the centers of the second explosion-proof hole 512, the second liquid injection hole 514, and the first through hole 511 of the lower insulating pad 51 are also on the same straight line. The second explosion-proof hole 512 and the second liquid injection hole 514 are located on opposite sides of the first through hole 511. Specifically, the lower insulating pad 51 also has several hollow holes 516. These hollow holes 516 are located on both sides of the straight line formed by the centers of the second explosion-proof hole 512, the second liquid injection hole 514, and the first through hole 511. The hollow holes 516 can reduce the weight of the lower insulating pad 51 and improve the overall lightweight structure.

[0049] Understandably, the present invention does not specifically limit the relative positions of the first explosion-proof 303, the first injection hole 304 and the receiving hole 301, as long as the injection and explosion-proof requirements are met.

[0050] The rivet block 20 is a fixing component in the cover plate assembly 100 and also a current-conducting component connecting the internal and external circuits of the battery. Its function is to rivet the upper negative electrode post 40, the upper insulating pad 52, the cover plate body 30, the lower insulating pad 51, and the sealing ring 53 together. If the cover plate assembly 100 is used as a negative electrode cover plate assembly, the rivet block 20 is made of pure copper and can function as a negative pressure rivet block; if the cover plate assembly 100 is used as a positive electrode cover plate assembly, the rivet block 20 is made of aluminum alloy and can function as a positive pressure rivet block. It passes through the through hole of the sealing ring 53, i.e., the sealing ring 53 is fitted onto the columnar body (i.e., the fixing part 22) of the rivet block 20, and the rivet block 20 with the sealing ring 53 on its outer ring then passes through the receiving hole 301 in the center of the cover plate body 30. The sealing ring 53 isolates the rivet block 20 from the contact between the cover plate body 30 and the cover plate body 30, thus serving as an insulating rivet block (negative electrode post body) and cover plate body.

[0051] When assembling the cover plate assembly 100, first, the sealing ring 53 is fitted onto the fixing part 22 of the rivet block 20. The top end of the fixing part 22 of the rivet block 20 passes sequentially through the lower insulating pad 51, the cover plate body 30, the upper insulating pad 52, and the pole post 40. By applying pressure to the top end of the fixing part 22 and the bottom end of the welding part 21 of the rivet block 20, the top end of the fixing part 22 is pressed into a wider top seat. The widened top seat is tightly clamped onto the through hole 401 of the pole post 40. At the same time, the sealing ring 53 also... Under pressure, the circular cylinder of the sealing ring 53 deforms towards the inner and outer sides of the cylindrical surface, filling and sealing the gap between the cylindrical fixing part 22 of the rivet block 20 and the receiving hole 301 at the center of the cover plate body 30. This realizes the function of the insulating rivet block (and the connected negative terminal) and the cover plate body, as well as the function of the sealing rivet block (and the connected negative terminal). The assembled cover plate assembly 100 has a low overall height, and the assembly process is simple and easy, with strong structural stability.

[0052] Please see Figure 2 , it is Figure 1The diagram shows the structure of the integrated busbar in the cover assembly of the large cylindrical battery. Specifically, there are two weld grooves 112, symmetrically arranged on both sides of the central hole 111. The flow hole 113 includes side holes 114. The two ends of the weld grooves 112 connect to the edges of the busbar 11. The middle part of the weld groove 112 bends towards the central hole 111 to form a curved portion 115. The side holes 114 are located on the side of the curved portion 115 away from the central hole 111. The curved weld grooves 112 maximize the use of the space in the busbar 11. The weld grooves 112 can serve as positioning grooves when welding to the end face of the battery cell, and can increase the welding area. The side holes 114 are approximately circular, and there are two side holes 114 located on both sides of the connecting piece 12 along its length. The two side holes 114 are, for example, a left through hole and a right through hole, providing flow channels on the left and right sides of the negative terminal face of the battery cell.

[0053] The flow hole 113 also includes an end hole 116, which is located between the two weld grooves 112. In this embodiment, there are two end holes 116, which are located at both ends of the busbar 11, for example, at the rear end of the busbar 11 near the connecting piece 12 and the front end of the busbar 11 away from the connecting piece 12, respectively. The end holes 116 are roughly triangular, and the edges of the end holes 116 are roughly parallel to the weld grooves 112, which can make maximum use of the space of the busbar 11 to provide an electrolyte flow channel.

[0054] In this embodiment, the busbar 11 and the connecting piece 12 are integrated into one structure. The integrated busbar 10 is located at one end of the cover plate assembly structure. The busbar 11 has through holes in the center, front and rear ends, left and right sides to increase the path for the electrolyte to flow and diffuse from the injection hole to the inside of the battery during the electrolyte injection process, thereby increasing the diffusion speed and improving the electrolyte absorption speed during the injection process, thus improving production efficiency.

[0055] Please see Figure 3 This is a structural diagram of an integrated busbar provided in another embodiment of the present invention. In some other embodiments, the number of flow holes 113 on the busbar 11 can be appropriately reduced to increase the current carrying capacity at the connection between the connecting piece 12 and the busbar 11. Reinforcing ribs 121 can also be protruded on the connecting piece 12 to increase its rigidity. Channel holes 122 can also be formed on the connecting piece 12 to increase the flow of electrolyte and improve electrolyte diffusion efficiency. It is understood that the above-mentioned various structures can be arbitrarily combined according to actual needs, and all are within the protection scope of the present invention.

[0056] The cover plate assembly 100 for the large cylindrical battery provided by the present invention achieves structural stability, electrical connectivity and safety throughout the entire life cycle of the large cylindrical battery through the specific geometric shape and spatial arrangement of each core component in a coordinated manner.

[0057] Specifically, firstly, if the cover plate assembly 100 is used as the positive electrode cover plate assembly, then the integrated busbar 10 serves as the positive electrode busbar and is located at the bottom of the cover plate assembly 100. This component is integrally formed from a hard, lightweight aluminum alloy material. Its internal integrated geometric reinforcing ribs and hollowed-out conductive electrolyte design aim to provide a larger conduction area for the positive electrode of the battery cell and improve the electrolyte diffusion rate during the electrolyte injection process. If the cover plate assembly 100 is used as the negative electrode cover plate assembly, then the integrated busbar 10 serves as the negative electrode busbar and is located at the bottom of the cover plate assembly 100. This component is integrally formed from a thin layer of pure copper or pure copper material with nickel plating on both the upper and lower surfaces (nickel plating thickness 1~3μm). Its internal integrated geometric reinforcing ribs and hollowed-out conductive electrolyte design aim to provide a larger conduction area for the negative electrode of the battery cell and improve the electrolyte diffusion rate during the electrolyte injection process. The connecting piece 12 of the integrated busbar 10 can also have reinforcing ribs and no elongated holes, which can reduce AC impedance, improve insulation reliability, reduce cost, and improve the structural robustness after the busbar is welded to the negative electrode tab. Secondly, the perforated annular disc mounted upwards is the lower insulating pad 51, which is usually made of high-temperature resistant, high-dielectric-strength composite engineering plastic or special ceramic coating. The receiving hole 301 in the center of the cover plate body 30 is a through hole for receiving the rivet block 20. The first receiving groove 302 above the receiving hole 301 provides for the installation and positioning design of the square protrusion on the lower surface of the upper insulating pad 52. After all the components of the cover plate assembly 100 are riveted, the first receiving groove 302 of the cover plate body 30 completely fits with the square protrusion on the lower surface of the upper insulating pad 52, and firmly fixes the pole post 40 in the second receiving groove 522 of the upper insulating pad 52, which can withstand a large enough torque to prevent the upper insulating pad 52 and the pole post 40 from loosening. The cover plate body 30 has a first injection hole 304 for injecting electrolyte, providing a channel for injecting electrolyte into the battery. Specifically, the upper side of the through hole of the first injection hole 304 is a concentric circular platform. This platform provides the physical position for positioning the sealing aluminum sheet of the injection hole and the material source for laser welding, so as to achieve sealing treatment of the injection hole when the electrolyte is injected.

[0058] Secondly, the top core safety component consists of an explosion-proof sheet 31 and a first explosion-proof hole 303. The first explosion-proof hole 303 provides a platform for welding and fixing the explosion-proof sheet 31, a physical fixing platform for the outer aluminum sheet of the explosion-proof sheet 31 when under pressure, and a support position for the arc-shaped end face of the explosion-proof sheet 31 when it flips outward to release stress and for mechanical shearing. This integrated component includes a plastic sheet with a central hole, namely a protective sheet 32, the explosion-proof sheet 31, and the first explosion-proof hole 303, all located above the explosion-proof sheet 31. When the internal pressure of the battery rises rapidly due to the generation of a large amount of gas under extreme operating conditions, this combined structure provides dual protection. That is, when the pressure reaches the preset flip threshold, the thin sheet on the explosion-proof sheet 31 located in the inner ring of the explosion-proof groove 311 is pushed upward and flipped under the action of air pressure. The explosion-proof sheet 31 will undergo irreversible plastic deformation or rupture along the explosion-proof groove 311, releasing the high-pressure mixed gas accumulated inside in a directional manner, thereby effectively alleviating the excessive mechanical load on the shell and preventing the shell explosion accident caused by thermal runaway.

[0059] Secondly, the central columnar structure at the very top is the electrode post 40, which serves as the main external negative electrical lead of the battery cell. The electrode post 40 and the cover plate are connected by precision friction welding, laser welding, or ultrasonic welding to achieve a high-strength metallurgical connection, ensuring the stability of contact resistance under high-rate charging and discharging and high-current conditions, and avoiding local overheating and electrochemical corrosion caused by loose connection.

[0060] Finally, to adapt to different requirements for current carrying capacity and electrolyte diffusion capacity, the integrated busbar 10 adopts an open or closed structure for the connecting piece 12, and a multi-part through-hole structure on the non-welded area of ​​the top busbar 10, i.e., the busbar piece 11. Furthermore, to improve the structural rigidity of the connecting piece 12, two reinforcing ribs (e.g., 5-25mm long, 0.5-3mm wide) can be added to the connecting piece 12 area at approximately 1 / 3 of the distance from the edge. Understandably, considering these requirements and corresponding structural designs, including but not limited to, minor adjustments can be made to the reinforcing ribs on the connecting piece, the number of openings in the connecting piece, and the number, position, and size of the through holes in the busbar piece. Without affecting the weld pool layout and welding effect, the through holes in the connecting piece and busbar piece can be circular, square, elliptical, oblong, etc., with an area of ​​1-40mm². 2 .

[0061] In summary, the cover plate assembly provided by this invention employs a large-area negative electrode busbar structure, significantly increasing the current path area. This design effectively reduces the battery's internal resistance and polarization, meets the heat dissipation requirements of large cylindrical batteries during high-rate charging and discharging, and improves the battery's cycle life and fast-charging performance. Furthermore, the busbar's connecting pieces utilize either perforated or non-perforated structures, and the non-welded areas of the busbar feature multiple through-holes. Reinforcing ribs are added to enhance the rigidity of the connecting piece structure. This integrated busbar design meets diverse requirements for current carrying capacity and electrolyte diffusion. The external electrode post design features a reasonable aspect ratio (cylindrical ratio) and chamfers, ensuring not only good mechanical strength but also optimizing the current extraction path and reducing contact resistance. The integrated annular sealing lip design between the electrode post and the insulating gasket, combined with precision laser welding, ensures excellent airtightness of the cover plate under high pressure and complex operating conditions, effectively preventing electrolyte evaporation and external moisture intrusion. Simultaneously, the selection of high-temperature resistant insulating materials guarantees the stability of the battery's insulation performance under prolonged high-temperature operating conditions, eliminating the risk of micro-short circuits and providing high airtightness and long-term reliability. The cover plate body, electrode post, and rivet block typically utilize high-strength aluminum alloy or copper components with specific structures to balance conductivity, thermal conductivity, and electrochemical corrosion resistance. This invention provides a highly integrated negative electrode cover plate with uniform current conduction, enabling self-protection and safe operation of large cylindrical batteries under extreme conditions.

[0062] like Figure 4 As shown, it is a structural diagram of the cover plate assembly provided in Embodiment 2 of the present invention. In Embodiment 2, the relative positions of the first explosion-proof 303, the first liquid injection hole 304 and the receiving hole 301 are changed based on Embodiment 1. The first explosion-proof 303, the first liquid injection hole 304 and the receiving hole 301 are designed such that the line connecting the centers of the three is at a 90-degree angle. Correspondingly, the line connecting the centers of the second explosion-proof hole 512, the second liquid injection hole 514 and the first through hole 511 of the lower insulating pad 51 is also at a 90-degree angle. The rest of the structure is basically the same as that in Embodiment 1, and will not be described in detail here.

[0063] like Figure 5 As shown, it is a structural diagram of the cover plate assembly provided in Embodiment 3 of the present invention. In Embodiment 3, the shape of the upper insulating pad 52 is changed based on Embodiment 1. The shape of the upper insulating pad 52 is designed to be circular. The rest of the structure is basically the same as that in Embodiment 1, and will not be described in detail here.

[0064] like Figure 6The diagram shown is a structural diagram of the cover plate assembly provided in Embodiment 4 of the present invention. In Embodiment 4, the shape of the upper insulating pad 52 is changed based on Embodiment 1. The upper insulating pad 52 is designed to be circular. Furthermore, the relative positions of the first explosion-proof 303, the first liquid injection hole 304, and the receiving hole 301 are changed. The line connecting the centers of the three circles of the first explosion-proof 303, the first liquid injection hole 304, and the receiving hole 301 forms a 90-degree angle. Correspondingly, the line connecting the centers of the three circles of the lower insulating pad 51—the second explosion-proof hole 512, the second liquid injection hole 514, and the first through hole 511—also forms a 90-degree angle. The remaining structure is basically the same as in Embodiment 1, and will not be described in detail here.

[0065] like Figures 7 to 10 As shown, it is a structural diagram of the cover plate assembly provided in Embodiments 5 to 8 of the present invention. Embodiments 5 to 8 correspond to Embodiments 1 to 4 respectively. Based on Embodiments 1 to 4, the number of flow holes 113 on the integrated manifold 10 is changed, and one of the end holes 116 near the connecting piece 12 is removed. The remaining structures are basically the same as those in Embodiments 1 to 4, and will not be described in detail here.

[0066] like Figures 11 to 14 As shown, it is a structural diagram of the cover plate assembly provided in Embodiments 9 to 12 of the present invention. Embodiments 9 to 12 correspond to Embodiments 1 to 4 respectively. Based on Embodiments 1 to 4, reinforcing ribs 121 are provided on the connecting piece 12 of the integrated manifold 10. There are two reinforcing ribs, which are arranged in parallel and along the length direction of the connecting piece 12. The remaining structures are basically the same as those in Embodiments 1 to 4, and will not be described in detail here.

[0067] like Figures 15 to 18 The diagram shows the structure of the cover plate assembly provided in Embodiments 13 to 16 of the present invention. Embodiments 13 to 16 correspond to Embodiments 1 to 4, respectively. Based on Embodiments 1 to 4, reinforcing ribs 121 are provided on the connecting piece 12 of the integrated manifold 10. There are two reinforcing ribs, which are arranged in parallel and along the length of the connecting piece 12. Furthermore, a channel hole 122 is added between the two reinforcing ribs 12. The channel hole 122 is specifically oblong and is located close to the manifold. The remaining structures are basically the same as those in Embodiments 1 to 4, and will not be described in detail here.

[0068] like Figures 19 to 22The diagram shows the structure of the cover plate assembly provided in Embodiments 17 to 20 of the present invention. Embodiments 17 to 20 correspond to Embodiments 1 to 4, respectively. Based on Embodiments 1 to 4, reinforcing ribs 121 are provided on the connecting piece 12 of the integrated manifold 10. There are two reinforcing ribs, which are arranged in parallel and along the length of the connecting piece 12. A channel hole 122 is added between the two reinforcing ribs 12. The channel hole 122 is oblong and is located close to the manifold. The number of flow holes 113 on the integrated manifold 10 is changed. One of the end holes 116 near the connecting piece 12 is removed. The remaining structures are basically the same as those in Embodiments 1 to 4, and will not be described in detail here.

[0069] like Figures 23 to 26 The diagram shows the structure of the cover plate assembly provided in Embodiments 21 to 24 of the present invention. Embodiments 21 to 24 correspond to Embodiments 1 to 4, respectively. Based on Embodiments 1 to 4, reinforcing ribs 121 are provided on the connecting piece 12 of the integrated manifold 10. There are two reinforcing ribs, which are arranged in parallel and along the length of the connecting piece 12. In addition, the number of flow holes 113 on the integrated manifold 10 is changed, and one of the end holes 116 near the connecting piece 12 is removed. The remaining structures are basically the same as those in Embodiments 1 to 4, and will not be described in detail here.

[0070] Please see Figure 27 The present invention also provides a large cylindrical battery 200, including a housing 201, a battery cell 202, and a cover plate assembly 100 of the large cylindrical battery described in any of the above embodiments. One end of the housing 201 is open, the battery cell 202 is housed within the housing 201, and the cover plate assembly 100 of the large cylindrical battery is disposed at the open end of the housing 201 and welded to the end face of the battery cell 202. Specifically, the housing 201 is cylindrical, the battery cell 202 is also cylindrical, and it is a multi-tab battery cell.

[0071] It should be noted that all embodiments of the cover plate assembly 100 for the large cylindrical battery provided by the present invention are applicable to the large cylindrical battery provided by the present invention and can achieve the same / similar technical effects. The present invention will not elaborate on them one by one.

[0072] In summary, the cover plate assembly 100 and the large cylindrical battery 200 provided by the present invention adopt an integrated busbar structure. The integrated busbar 10 includes a busbar plate 11 and a connecting piece 12 extending from the busbar plate 11. The busbar plate 11 has a through central hole 111 in its center. The busbar plate 11 also has a plurality of weld grooves 112 and flow holes 113, which are located around the central hole 111. The rivet block 20 includes a welding part 21 and a connecting piece located at the welding part 21. The cover plate body 30 has a through-hole 301 at its center, and the electrode post 40 has a through-hole 401. The welding groove 112 of the busbar 11 is used for welding to the end face of the battery cell. The end of the connecting piece 12 away from the busbar 11 is bent and welded to the welding part 21 for fixation. The fixing part 22 passes through the through-hole 301 and the through-hole 401 and is riveted to fix the cover plate body 30 and the electrode post 40. The insulating component 50 is located between the cover plate body 30 and the riveting block 20 or between the cover plate body 30 and the electrode post 40. This invention, by optimizing the electrode post connection method and the integrated structure design of the busbar, can increase the current carrying area, effectively solve the problem of uneven current distribution when connecting large-diameter battery cell tabs, has a compact structure, high safety and reliability, is conducive to electrolyte wetting of the battery cell, has low impedance and high current sharing characteristics, can comprehensively improve the intrinsic safety level and electrochemical performance of the battery, and can also effectively reduce the risk of internal thermal runaway of the battery, and improve the assembly efficiency and cycle life of large cylindrical batteries.

[0073] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A cover plate assembly for a large cylindrical battery, characterized in that, The device includes an integrated busbar, a riveting block, a cover plate body, a terminal post, and an insulation component. The integrated busbar includes a busbar plate and a connecting piece extending from the busbar plate. The busbar plate has a through-hole at its center and several weld grooves and flow holes located around the center hole. The riveting block includes a welding part and a fixing part located on the welding part. The cover plate body has a through-hole at its center, and the terminal post has a through hole. The weld grooves of the busbar plate are used for welding to the end face of the battery cell. The end of the connecting piece away from the busbar plate is bent and welded to the welding part for fixation. The fixing part passes through the through-hole and the receiving hole and is riveted to fix the cover plate body and the terminal post. The insulation component is located between the cover plate body and the riveting block or between the cover plate body and the terminal post.

2. The cover plate assembly of the large cylindrical battery as described in claim 1, characterized in that, The insulating component includes a lower insulating pad with a first through hole at its center. The lower insulating pad is located between the welding part and the cover plate body, and the fixing part passes through the first through hole.

3. The cover plate assembly of the large cylindrical battery as described in claim 2, characterized in that, The insulating assembly further includes an upper insulating pad, the upper insulating pad having a second through hole at its center, through which the fixing part passes; a first receiving groove is formed on the surface of the cover plate body away from the connecting piece, the first receiving groove communicating with the receiving hole, the upper insulating pad being received in the first receiving groove, a second receiving groove is formed on the surface of the upper insulating pad away from the cover plate body, and the pole post being received in the second receiving groove; the insulating assembly further includes a sealing ring, the sealing ring being fitted onto the fixing part.

4. The cover plate assembly of the large cylindrical battery as described in claim 1, characterized in that, The cover plate body also has a through first explosion-proof hole, which is located around the receiving hole. An explosion-proof sheet is received in the first explosion-proof hole. The explosion-proof sheet is stamped with explosion-proof markings and is covered with a protective sheet.

5. The cover plate assembly of the large cylindrical battery as described in claim 4, characterized in that, The lower insulating pad has a second explosion-proof hole, which is opposite to the first explosion-proof hole. A first partition connecting the edge of the second explosion-proof hole is provided inside the second explosion-proof hole.

6. The cover plate assembly of the large cylindrical battery as described in claim 1, characterized in that, The cover plate body is also provided with a through first liquid injection hole, which is located around the receiving hole; the lower insulating pad is provided with a second liquid injection hole, which is opposite to the first liquid injection hole, and a second partition connecting the edge of the second liquid injection hole is provided inside the second liquid injection hole.

7. The cover plate assembly of the large cylindrical battery as described in claim 1, characterized in that, The number of weld grooves is two, and the two weld grooves are symmetrically arranged on both sides of the central hole. The flow hole includes a side hole. The two ends of the weld groove are connected to the edge of the manifold. The middle part of the weld groove is bent towards the central hole to form a curved part. The side hole is located on the side of the curved part away from the central hole.

8. The cover plate assembly of the large cylindrical battery as described in claim 7, characterized in that, The flow hole also includes an end hole, which is located between the two weld grooves.

9. The cover plate assembly of the large cylindrical battery as described in claim 8, characterized in that, The connecting piece is provided with reinforcing ribs, and / or the connecting piece is provided with channel holes.

10. A large cylindrical battery, characterized in that, The battery includes a housing, a battery cell, and a cover plate assembly for a large cylindrical battery as described in any one of claims 1-9. One end of the housing is open, the battery cell is housed within the housing, and the cover plate assembly for the large cylindrical battery is disposed at one end of the opening in the housing and welded to the end face of the battery cell.

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