Cover plate assembly, cell assembly and battery pack

Abstract

The application provides a cover plate assembly, a battery cell assembly and a battery pack, and aims to improve the energy density of the battery pack and reduce the weight of the battery pack. The first cover plate of the cover plate assembly has a first through hole. The outer circumferential surface of the first pole post has a first protruding portion. The first fixing ring is arranged in the first through hole and fixedly connected with the first cover plate; the first fixing ring is sleeved on the first pole post and includes a first ring segment, a second ring segment and a third ring segment which are sequentially connected in the axial direction, and the first ring segment and the third ring segment clamp the first protruding portion from the two axial sides of the first pole post. The second cover plate is laminated and spaced apart from the first cover plate, and the second cover plate has a second through hole. The second pole post is arranged in the second through hole and fixedly connected with the second cover plate; the second pole post is welded with the first pole post. The first pole post and the second pole post are respectively used for being connected with two tabs with opposite polarities of two battery monomers. The cover plate assembly provided by the application is beneficial to improving the energy density of the battery pack.

Description

Technical Field

[0001] This application relates to the field of new energy equipment technology, specifically to a cover plate assembly, a cell assembly, and a battery pack. Background Technology

[0002] In the field of battery technology, especially in battery packs that integrate multiple cells into a higher voltage configuration, it is often necessary to electrically connect multiple cells in series. To achieve series connection between cells, related technologies often utilize external metal busbars. Specifically, operators need to bridge the terminals connected to the positive and negative poles of two adjacent cells using a separate busbar component, and typically, welding is used to secure and electrically connect the busbar to the two terminals.

[0003] However, this series connection method based on busbar welding has problems such as a large number of parts, complex assembly process, high manufacturing cost, limitation of the overall energy density of the battery pack, and difficulty in further weight reduction. Summary of the Invention

[0004] This application provides a cover plate assembly, a cell assembly, and a battery pack to address the issues of how to improve the energy density of the battery pack and reduce its weight.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: In a first aspect, embodiments of this application provide a cover plate assembly, which includes a first cover plate, a first electrode post, a first fixing ring, a second cover plate, and a second electrode post. The first cover plate has a first through hole. The outer peripheral surface of the first electrode post has a first protrusion. The first fixing ring passes through the first through hole and is fixedly connected to the first cover plate; the first fixing ring is sleeved on the first electrode post and includes a first ring segment, a second ring segment, and a third ring segment connected sequentially along the axial direction, the first ring segment and the third ring segment clamping the first protrusion from both sides of the first electrode post along the axial direction. The second cover plate is stacked on top of the first cover plate and spaced apart, and the second cover plate has a second through hole. The second electrode post passes through the second through hole and is fixed relative to the second cover plate; the second electrode post is welded to the first electrode post. The first electrode post is used to connect to the first tab of a first battery cell, and the second electrode post is used to connect to the second tab of a second battery cell, the polarity of the first tab being opposite to the polarity of the second tab.

[0006] The cover plate assembly provided in this application, by having a first fixing ring sleeved on a first pole post, with the first ring segment and the third ring segment of the first fixing ring clamping a first protrusion, and the first fixing ring passing through a first through hole and fixedly connected to the first cover plate, enables the first pole post and the first cover plate to be relatively fixed in the axial direction, and facilitates connection with the first tab of the first battery cell; by having a second pole post passing through a second through hole in the second cover plate, the second pole post can be easily connected with the second tab of the second battery cell; by welding the first pole post and the second pole post, the first cover plate and the second cover plate can be relatively fixed, thereby enabling the first battery cell and the second battery cell to be relatively fixed and electrically connected.

[0007] Therefore, when the cover plate assembly is applied to the cell assembly, electrical connection between two cells can be achieved without the need for an external busbar. This reduces the number of components in the battery pack, simplifies assembly and welding processes, and improves space utilization within the battery pack, thereby reducing the weight of the battery pack and increasing its energy density. Furthermore, this electrical connection method reduces the number of connection interfaces in the series path of the two cells, thus improving the reliability of the electrical connection and the overall safety of the battery pack.

[0008] Furthermore, by clamping the first protrusion of the first terminal post with the two segments of the first fixing ring, a first terminal post assembly with complete functionality and a stable structure can be formed before assembly to the first cover plate. This facilitates individual dimensional inspection, sealing testing, and electrical testing of the first terminal post assembly, thereby improving the quality consistency and reliability of the cover plate assembly. It also enhances the modularity and standardization of cover plate assembly production and reduces the overall assembly complexity, thus simplifying material management and assembly processes on the battery pack production line. In addition, it improves the applicability of the first terminal post assembly to different types of battery cell assemblies.

[0009] In some possible implementations of the first aspect, the outer peripheral surface of the second pole post has a second protrusion. The cover plate assembly also includes a second retaining ring, which passes through a second through hole and is fixedly connected to the second cover plate. The second retaining ring is sleeved on the second pole post and includes a fourth ring segment, a fifth ring segment, and a sixth ring segment connected sequentially along the axial direction, the fourth ring segment and the sixth ring segment clamping the second protrusion from both axial sides of the second pole post.

[0010] In some possible implementations of the first aspect, the cover plate assembly further includes a first insulating member sleeved on the first pole post and located between the outer peripheral surface of the first pole post and the inner peripheral surface of the first fixing ring, with the end face of the first insulating member facing the second cover plate located between the first fixing ring and the second cover plate.

[0011] In some possible implementations of the first aspect, the cover plate assembly further includes a second insulating member sleeved on the second pole post and located between the outer peripheral surface of the second pole post and the inner peripheral surface of the second fixing ring, with the end face of the second insulating member facing the first cover plate located between the second fixing ring and the first cover plate.

[0012] In some possible implementations of the first aspect, the cover plate assembly further includes a first insulating member and a second insulating member. The first insulating member is sleeved on the first pole post and located between the outer peripheral surface of the first pole post and the inner peripheral surface of the first fixing ring, with the end face of the first insulating member facing the second cover plate located between the first fixing ring and the second cover plate. The second insulating member is sleeved on the second pole post and located between the outer peripheral surface of the second pole post and the inner peripheral surface of the second fixing ring, with the end face of the second insulating member facing the first cover plate located between the second fixing ring and the first cover plate.

[0013] In some possible implementations of the first aspect, the distance L1 between the first insulator and the second insulator satisfies: L1 ≥ 0.1 mm.

[0014] In some possible implementations of the first aspect, the cover plate assembly further includes a third insulating member and a fourth insulating member. The third insulating member is sleeved on the first pole post and located on the side of the first fixing ring facing the second cover plate, and the third insulating member is in contact with both the first fixing ring and the first insulating member. The fourth insulating member is sleeved on the second pole post and located on the side of the second fixing ring facing the first cover plate, the fourth insulating member is spaced apart from the third insulating member, and is in contact with both the second fixing ring and the second insulating member.

[0015] In some possible implementations of the first aspect, the first pole post includes a first pole segment and a second pole segment connected together, the first pole segment being annular and the second pole segment being plate-shaped, the second pole segment being welded to the second pole post to form a first welded portion, the first welded portion being located on the inner circumference of the first pole segment.

[0016] In some possible implementations of the first aspect, the cover assembly further includes a fifth insulating element, which is stacked between the first cover and the second cover and connected to at least one of the first cover and the second cover.

[0017] In some possible implementations of the first aspect, the first pole post includes a first column segment and a second column segment connected together. The first column segment is annular, and the second column segment is plate-shaped. The second column segment is welded to the second pole post to form a first welded portion, which is located on the inner circumferential side of the first column segment. The cover plate assembly also includes a fifth insulating member, which is stacked between the first cover plate and the second cover plate and connected to at least one of the first cover plate and the second cover plate.

[0018] In some possible implementations of the first aspect, the second pole post includes a third pole post and a fourth pole post that are connected and made of different materials. The fourth pole post is made of the same material as the first pole post, and the fourth pole post is welded to the first pole post to form a first weld joint.

[0019] In some possible implementations of the first aspect, the end face of the second pole post facing away from the first pole post has a first groove, the orthographic projection of the first welded portion in the first plane overlaps with the orthographic projection of the first groove in the first plane, and the first plane is perpendicular to the axis of the second pole post.

[0020] In some possible implementations of the first aspect, the length H1 of the second column segment along the axial direction of the first pole column satisfies: 0.5mm ≤ H1 ≤ 2.5mm.

[0021] In some possible implementations of the first aspect, the second pole post includes a third and a fourth pole post connected to each other and made of different materials. The fourth pole post is made of the same material as the first pole post, and the fourth pole post is welded to the first pole post to form a first weld joint. The end face of the second pole post facing away from the first pole post has a first groove. The orthographic projection of the first weld joint in a first plane overlaps with the orthographic projection of the first groove in the first plane, and the first plane is perpendicular to the axial direction of the second pole post. The length H1 of the second pole post along the axial direction of the first pole post satisfies: 0.5mm ≤ H1 ≤ 2.5mm.

[0022] In some possible implementations of the first aspect, the first groove is formed on the third column segment, and the distance L2 between the bottom wall of the first groove and the fourth column segment satisfies: L2≥0.5mm.

[0023] In some possible implementations of the first aspect, a portion of the second protrusion is formed in the third column segment, and another portion is formed in the fourth column segment.

[0024] In some possible implementations of the first aspect, a first groove is formed in the third column segment, and the distance L2 between the bottom wall of the first groove and the fourth column segment satisfies: L2 ≥ 0.5 mm. A portion of the second protrusion is formed in the third column segment, and another portion is formed in the fourth column segment.

[0025] In some possible implementations of the first aspect, both the first and fourth ring segments are located between the first and second cover plates; the cover plate assembly further includes a first sealing ring and a second sealing ring. The first sealing ring is fitted onto the first pole post and provides an insulating seal between the first pole post and the third ring segment. The second sealing ring is fitted onto the second pole post and provides an insulating seal between the second pole post and the sixth ring segment; wherein the interface between the third and fourth pole segments is located between the second and third sealing rings.

[0026] Secondly, embodiments of this application provide a battery cell assembly, which includes a first battery cell and a second battery cell. The first battery cell and the second battery cell are connected by a cover plate assembly, which is any of the cover plate assemblies provided in the first aspect described above. The first battery cell includes a first tab and a first cover plate. The first tab is located on the side of the first cover plate opposite to the second cover plate and is connected to a first terminal post. The second battery cell includes a second tab and a second cover plate. The second tab is located on the side of the second cover plate opposite to the first cover plate and is connected to a second terminal post. The polarity of the second tab is opposite to that of the first tab.

[0027] Thirdly, embodiments of this application provide a battery pack, which includes at least one battery cell assembly, wherein the battery cell assembly is the aforementioned battery cell assembly.

[0028] Fourthly, embodiments of this application provide an electrical device, which includes a power-consuming body and a battery pack. The battery pack is the aforementioned battery pack, and the battery pack is electrically connected to the power-consuming body.

[0029] The beneficial technical effects of the cell assembly, battery pack, and electrical equipment provided in this application are the same as those of the cover plate assembly provided in this application, and will not be repeated here. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an electrical device provided for some embodiments of this application.

[0031] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the battery pack of the electrical device.

[0032] Figure 3 for Figure 2 The diagram shows a partial structural schematic of the battery pack at line AA.

[0033] Figure 4 for Figure 3 A perspective view of the cover plate device for the shown battery cell assembly.

[0034] Figure 5 for Figure 4 Top view of the cover plate assembly shown.

[0035] Figure 6 for Figure 5 The diagram shows a cross-sectional view of the cover plate assembly at the BB line.

[0036] Figure 7 for Figure 6 The exploded view of the cover plate assembly shown.

[0037] Figure 8 for Figure 6 The diagram shows the cross-sectional structure of the first pole post assembly of the cover plate assembly.

[0038] Figure 9 for Figure 6 The cross-sectional structural diagram of the second pole post assembly of the cover plate assembly shown.

[0039] Figure 10 for Figure 5 The diagram shows another cross-sectional view of the cover plate assembly at the BB line.

[0040] Figure 11 for Figure 5 Another cross-sectional view of the cover plate assembly at the BB line.

[0041] Figure 12 for Figure 5 The diagram shows another cross-sectional structure of the cover plate assembly at the BB line.

[0042] Figure 13 for Figure 2 Another cross-sectional view of the cover assembly of the battery pack shown.

[0043] Figure label: 1000 - Electrical equipment; 110 - Main power supply unit; 110a - Battery compartment; 120-battery pack; 121 - Box body; 121a - First inner cavity; 122-Cell assembly; 122A-First cell; 10A-First housing; 10A1-First receiving cavity; 10A2-First opening; 10B-First electrode group; 10B1-First electrode tab; 122B-Second cell; 10C-Second housing; 10C1-Second receiving cavity; 10C2-Second opening; 10D-Second electrode group; 10D1-Second electrode tab; 30-Cover assembly; 30A-Welded part; 31-First cover plate; 31a-First through hole; 31b-First limiting groove; 32-Second cover plate; 32a-Second through hole; 33-First pole assembly; 331-First pole; 331a-First protrusion; 3311-First pole segment; 3312-Second pole segment; 332-First 3321 - First ring segment; 3322 - Second ring segment; 3323 - Third ring segment; 3324 - First limiting protrusion; 333 - First insulating component; 334 - First sealing ring; 335 - Third insulating component; 34 - Second pole post assembly; 341 - Second pole post; 341a - Second protrusion; 341b - First groove; 3411 - Third column segment; 3412 - Fourth column segment; 342 - Second fixing ring; 3421 - Fourth ring segment; 3422 - Fifth ring segment; 3423 - Sixth ring segment; 343 - Second insulating component; 344 - Second sealing ring; 345 - Fourth insulating component; 35 - Insulating assembly; 351 - Sixth insulating component; 352 - Seventh insulating component; 353 - Fifth insulating component. Detailed Implementation

[0044] In the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0045] In the embodiments of this application, it should be understood that the directional terms mentioned, such as "up", "down", "left", "right", "inner", "outer", etc., are only for reference to the direction of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0046] In the embodiments of this application, the terms "first," "second," "third," "fourth," "fifth," "sixth," and "seventh" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," "third," "fourth," "fifth," "sixth," and "seventh" may explicitly or implicitly include one or more of that feature.

[0047] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0048] In the embodiments of this application, "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In the embodiments of this application, it should be noted that the descriptions of "vertical" and "parallel" respectively indicate approximately vertical and approximately parallel within a certain error range. This error range can be a range where the deviation angle relative to absolute verticality and absolute parallelism is less than or equal to 5°, 8°, 10° or 20°, respectively, and is not specifically limited here.

[0050] In the field of battery technology, especially in battery packs that integrate multiple cells into a higher voltage configuration, it is often necessary to electrically connect multiple cells in series. To achieve series connection between cells, related technologies often utilize external metal busbars. Specifically, operators need to bridge the terminals connected to the positive and negative poles of two adjacent cells using a separate busbar component, and typically, welding is used to secure and electrically connect the busbar to the two terminals.

[0051] However, this series connection method based on busbar welding has problems such as a large number of parts, complex assembly process, high manufacturing cost, limitation of the overall energy density of the battery pack, and difficulty in further weight reduction.

[0052] To address the aforementioned issues, this application provides a cover plate assembly. By forming a first fixing ring and a first terminal post into a terminal post assembly, this assembly penetrates and is fixed to the first cover plate. A second terminal post penetrates and is fixed to the second cover plate. The first and second terminal posts are welded together, allowing the cover plate assembly to encapsulate two battery cells respectively through the first and second cover plates. Furthermore, the first and second terminal posts are electrically connected to the positive and negative electrode tabs within the two battery cells, respectively, thereby connecting the two cells in series. This reduces the lateral space occupied by the two connected battery cells and shortens the series current path, thus reducing the weight of the battery pack and increasing its energy density.

[0053] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0054] Please see Figure 1 , Figure 1 This is a schematic diagram of an electrical device 1000 provided in some embodiments of this application. Figure 1 In the illustrated embodiment, an electric vehicle is used as an example of the electrical device 1000 for illustrative purposes, which should not be construed as a specific limitation of this application. In other embodiments, the electrical device 1000 may also be a mobile phone, a laptop computer, an energy storage system, or other similar devices.

[0055] Please continue reading. Figure 1 The electrical device 1000 includes a power-consuming body 110 and a battery pack 120. The battery pack 120 is fixed to the power-consuming body 110 and electrically connected to the power-consuming components of the power-consuming body 110 to supply power to the power-consuming components of the power-consuming body 110. Specifically, the power-consuming body 110 may have a battery compartment 110a, and the battery pack 120 is fixed inside the battery compartment 110a.

[0056] Please see Figure 2 , Figure 2 for Figure 1 The diagram shows a cross-sectional view of the battery pack 120 of the electrical device 100. The battery pack 120 may include a housing 121 and at least one battery cell assembly 122. The housing 121 encloses a first inner cavity 121a. The battery cell assembly 122 is disposed in the first inner cavity 121a of the housing 121 and is fixed relative to the housing 121. The housing 121 protects the battery cell assembly 122 from external forces causing vibration and impact that could damage it. The housing 121 may be a metal structure or a plastic structure.

[0057] The battery cell assembly 122 includes multiple battery cells connected in series. A battery cell is the most basic electrochemical unit, capable of storing and releasing electrical energy. Battery cells can be lithium-ion cells, sodium-ion cells, sodium-lithium-ion cells, lithium metal cells, sodium metal cells, lithium-sulfur cells, magnesium-ion cells, nickel-metal hydride cells, nickel-cadmium cells, lead-acid cells, etc.

[0058] Figure 2In the battery pack 120 shown, there are multiple cell assemblies 122. These multiple cell assemblies 122 can be electrically connected in series, in parallel, or in a mixed configuration. A mixed configuration means that the multiple cell assemblies 122 are connected in both series and parallel relationships, which can be specifically designed according to the power consumption requirements of the electrical device 1000. In some other embodiments, the battery pack 120 may contain only one cell assembly 122.

[0059] Please refer to the following: Figures 2-4 , Figure 3 for Figure 2 The diagram shows a partial cross-sectional view of the battery pack 120 at line AA. Figure 4 for Figure 3 The diagram shows a perspective view of the cover assembly 30 of the battery cell assembly 122. The battery cell assembly 122 includes a first battery cell 122A and a second battery cell 122B. The first battery cell 122A and the second battery cell 122B are connected by the cover assembly 30. Specifically, the first battery cell 122A includes a first housing 10A and a first electrode group 10B. The first housing 10A has a first receiving cavity 10A1 and a first opening 10A2 communicating with the first receiving cavity 10A1. The first electrode group 10B is located within the first receiving cavity 10A1 and is immersed in the electrolyte. The second battery cell 122B includes a second housing 10C and a second electrode group 10D. The second housing 10C has a second receiving cavity 10C1 and a second opening 10C2 communicating with the second receiving cavity 10C1. The second electrode group 10D is located within the second receiving cavity 10C1 and is immersed in the electrolyte.

[0060] Figure 2 and Figure 3 In the illustrated embodiment, the first housing 10A and the second housing 10C are generally rectangular, so that the corresponding battery cell is also generally rectangular. The first housing 10A and the second housing 10C can be metal housings. In some examples, the first housing 10A and the second housing 10C can be aluminum alloy housings to make the housings lighter, which is beneficial for the lightweighting of the battery cell assembly 122, and thus for the overall lightweighting of the electrical device 1000. In other examples, the first housing 10A and the second housing 10C can also be stainless steel housings, titanium alloy housings, etc., to make the housings have higher strength, thus giving the battery cell assembly 122 better overall strength and stronger resistance to puncture and vibration damage. In other embodiments, the first housing 10A and the second housing 10C can also be cylindrical, irregularly shaped, etc.

[0061] The first electrode assembly 10B includes a positive electrode sheet (not shown in the figure), a negative electrode sheet (not shown in the figure), and a separator (not shown in the figure). The positive electrode sheet can be formed from a positive current collector and a positive active material coated on the positive current collector. In some examples, the positive current collector can be aluminum foil, and the positive active material can be lithium cobalt oxide (LCO), ternary materials (NCM / NCA), lithium iron phosphate (LFP), etc. Based on this, the first electrode assembly 10B also includes a first tab 10B1, which is connected to the positive electrode sheet and electrically conductive; that is, the first tab 10B1 is the positive tab of the first cell 122A. Specifically, the first tab 10B1 is made of the same material as the positive current collector, and the first tab 10B1 can be fixed to the positive current collector by welding or integrally formed with the positive current collector.

[0062] The negative electrode sheet can be formed from a negative current collector and a negative active material coated on the negative current collector. In some examples, the negative current collector can be copper foil, and the negative active material can be graphite, silicon-carbon composite material, etc. Based on this, the first electrode group 10B also includes a third tab (not shown in the figure), which is connected to the negative electrode sheet and electrically conductive. The third tab and the first tab 10B1 are used to electrically connect the first electrode group 10B to the circuit. Specifically, the third tab can be fixed to the negative current collector by welding or integrally formed with the negative current collector. In some other embodiments, the material of the first tab 10B1 can also be the same as that of the negative current collector. The first tab 10B1 is connected to the negative electrode sheet and electrically conductive, and the third tab is connected to the positive electrode sheet and electrically conductive, that is, the first tab 10B1 is the negative tab of the first battery cell 122A.

[0063] A separator is placed between the positive and negative electrode plates to isolate them and prevent short circuits. The separator can be made of porous polyethylene (PE) or polypropylene (PP), etc.

[0064] The structure of the second electrode group 10D can refer to the structure of the first electrode group 10B. Specifically, the second electrode tab 10D1 of the second electrode group 10D can be connected to either the positive or negative electrode plate of the second electrode group 10D and be electrically conductive. The material of the second electrode tab 10D1 can be the same as the connected current collector, and the polarity of the second electrode tab 10D1 is opposite to that of the aforementioned first electrode tab 10B1.

[0065] Please refer to the following: Figures 5-8 , Figure 5 for Figure 4 The top view of the cover plate assembly 30 shown. Figure 6 for Figure 5 The diagram shows a cross-sectional view of the cover plate assembly 30 at line BB. Figure 7 This is an exploded view of the cover plate assembly 30 shown in Figure 6. Figure 8 for Figure 6 The diagram shows a cross-sectional view of the first electrode assembly 33 of the cover plate assembly 30. The cover plate assembly 30 includes a first cover plate 31, a second cover plate 32, a first electrode assembly 33, a second electrode assembly 34, and an insulating assembly 35. The first cover plate 31 forms part of the first cell 122A, and the outer contour shape of the first cover plate 31 can be adapted to the shape of the first opening 10A2. The first cover plate 31 can be connected to the first housing 10A by means of bonding, snap-fitting, threaded connection, welding, etc., to seal the first opening 10A2, thereby protecting the first electrode group 10B and preventing electrolyte leakage in the first cell 122A. The first cover plate 31 has a first through hole 31a, which communicates with the first receiving cavity 10A1.

[0066] Specifically, the first cover plate 31 is generally plate-shaped, and the first through hole 31a is generally circular. The first cover plate 31 is a metal structural component. In some examples, the first cover plate 31 can be an aluminum alloy structural component, which is beneficial for the lightweight design of the first battery cell 122A. In other examples, the first cover plate 31 can be a stainless steel component to give the first cover plate 31 higher strength, thereby giving the first battery cell 122A higher strength. In other embodiments, the first through hole 31a can also be oblong, elliptical, polygonal, etc.

[0067] The first pole post assembly 33 includes a first pole post 331 and a first fixing ring 332. The outer peripheral surface of the first pole post 331 has a first protrusion 331a. Specifically, the first protrusion 331a can form a continuous ring structure or a discontinuous ring structure, and the first protrusion 331a can be formed by upsetting, turning, welding, etc. The first protrusion 331a is spaced apart from both end faces of the first pole post 331.

[0068] The first fixing ring 332 passes through the first through hole 31a of the first cover plate 31 and is fixedly connected to the first cover plate 31. Specifically, the first fixing ring 332 can be a metal structural component, and the first fixing ring 332 can be fixedly connected to the first cover plate 31 by welding, bonding, snap-fitting, threaded connection, etc. The axis of the first fixing ring 332 is approximately coincident with the axis of the first through hole 31a. The first fixing ring 332 is sleeved on the first pole post 331 and includes a first ring segment 3321, a second ring segment 3322, and a third ring segment 3323 connected sequentially along the axial direction. The first ring segment 3321 and the third ring segment 3323 clamp the first protrusion 331a from both sides of the axial direction of the first pole post 331. Specifically, the first fixing ring 332 can be arranged around the first pole post 331, and the first ring segment 3321 and / or the third ring segment 3323 can be formed by a flanging process.

[0069] The second cover plate 32 forms part of the second cell 122B, and its outer contour shape is adapted to the shape of the second opening 10C2. The second cover plate 32 is connected to the second housing 10C to seal the second opening 10C2, thereby protecting the second electrode assembly 10D and preventing electrolyte leakage from the second cell 122B. The second cover plate 32 is stacked and spaced apart from the first cover plate 31. The second cover plate 32 has a second through hole 32a, which communicates with the second receiving cavity 10C1. That is, the first tab 10B1 is located on the side of the first cover plate 31 facing away from the second cover plate 32, and the second tab 10D1 is located on the side of the second cover plate 32 facing away from the first cover plate 31.

[0070] The second electrode assembly 34 includes a second electrode 341, which passes through the second through hole 32a of the second cover plate 32 and is fixed relative to the second cover plate 32. Based on this, the second electrode 341 is welded to the first electrode 331. Furthermore, the first electrode 331 is connected to the first tab 10B1 of the first battery cell 122A, that is, the first electrode 331 is used to connect to the first tab 10B1 of the first battery cell 122A. Specifically, the first electrode 331 can be connected to the first tab 10B1 of the first battery cell 122A by welding or bonding with conductive adhesive. The second electrode 341 is connected to the second tab 10D1 of the second battery cell 122B, that is, the second electrode 341 is used to connect to the second tab 10D1 of the second battery cell 122B. Specifically, the second electrode 341 can be connected to the second tab 10D1 of the second battery cell 122B by welding or bonding with conductive adhesive.

[0071] In this way, the cover plate assembly 30 provided in this application, by having the first fixing ring 332 sleeved on the first pole post 331, and the first ring segment 3321 and the third ring segment 3323 of the first fixing ring 332 clamping the first protrusion 331a, and the first fixing ring 332 passing through the first through hole 31a and fixedly connected to the first cover plate 31, enables the first pole post 331 and the first cover plate 31 to be relatively fixed in the axial direction, and facilitates connection with the first tab 10B1 of the first battery cell 122A; by having the second pole post 341 pass through the second through hole 32a of the second cover plate 32, the second pole post 341 can be easily connected with the second tab 10D1 of the second battery cell 122B; by welding the first pole post 331 and the second pole post 341, the first cover plate 31 and the second cover plate 32 can be relatively fixed, thereby enabling the first battery cell 122A and the second battery cell 122B to be relatively fixed and electrically connected.

[0072] Therefore, the electrical connection of two cells can be achieved without the need for an external busbar, which reduces the number of components in the battery pack 120, simplifies assembly and welding processes, and improves the space utilization within the battery pack 120, thereby reducing the weight of the battery pack 120 and increasing its energy density. Furthermore, this electrical connection method reduces the number of connection interfaces in the series path of the two cells, thus improving the reliability of the electrical connection and the overall safety of the battery pack 120.

[0073] Furthermore, by clamping the first protrusion 331a of the first terminal post 331 with the two segments of the first fixing ring 332, a first terminal post assembly 33 with complete function and stable structure can be formed before assembly to the first cover plate 31. This facilitates individual dimensional inspection, sealing test, and electrical test of the first terminal post assembly 33, thereby improving the quality consistency and reliability of the cover plate assembly 30. It also enhances the modularity and standardization of the production of the cover plate assembly 30 and reduces the overall assembly complexity of the cover plate assembly 30, thus simplifying material management and assembly processes on the battery pack 120 production line. On this basis, it also improves the applicability of the first terminal post assembly 33 to different models of battery cell assemblies 122.

[0074] Please continue reading. Figures 5-8 The inner circumferential surface of the first through hole 31a has a first limiting groove 31b, which extends circumferentially along the first through hole 31a and penetrates one surface of the first cover plate 31 along its thickness direction. Based on this, the first fixing ring 332 also includes a first limiting protrusion 3324, which is connected to the outer circumferential surface of the second ring segment 3322 and extends circumferentially along the first fixing ring 332. The first limiting protrusion 3324 is accommodated and fitted within the first limiting groove 31b. Specifically, the surface of the first limiting protrusion 3324 facing away from the groove sidewall of the first limiting groove 31b is flush with that surface of the first cover plate 31, and the surface of the first cover plate 31 facing away from the groove sidewall of the first limiting groove 31b is flush with the end face of the first fixing ring 332 facing the same direction. Based on this, one or both of the first limiting protrusion 3324 and the first fixing ring 332 are connected to the first cover plate 31 by seam welding.

[0075] Please refer to the following: Figures 5-7 , Figure 9 , Figure 9 for Figure 6 The diagram shows a cross-sectional view of the second pole post assembly 34 of the cover plate assembly 30. The outer peripheral surface of the second pole post 341 has a second protrusion 341a. Specifically, the second protrusion 341a can form a continuous annular structure or a discontinuous annular structure. The second protrusion 341a is spaced apart from both end faces of the second pole post 341.

[0076] The second pole post assembly 34 also includes a second fixing ring 342, which passes through the second through hole 32a of the second cover plate 32 and is fixedly connected to the second cover plate 32. Specifically, the second fixing ring 342 can be a metal structural component, and can be fixedly connected to the second cover plate 32 by welding, bonding, snap-fitting, threaded connection, etc. The axis of the second fixing ring 342 is approximately coincident with the axis of the second through hole 32a. The second fixing ring 342 is sleeved on the second pole post 341 and includes a fourth ring segment 3421, a fifth ring segment 3422, and a sixth ring segment 3423 connected sequentially along the axial direction. The fourth ring segment 3421 and the sixth ring segment 3423 clamp the second protrusion 341a from both sides of the axial direction of the second pole post 341. Specifically, the second fixing ring 342 can be arranged around the second pole post 341, and the fourth ring segment 3421 and / or the sixth ring segment 3423 can be formed by a flanging process.

[0077] The structure of the second fixing ring 342 and its connection with the second cover plate 32 can be referenced to the structure of the first fixing ring 332 and its connection with the first cover plate 31. The technical effect of the connection between the second fixing ring 342, the second cover plate 32, and the second pole post 341 can be referenced to the technical effect of the connection between the first fixing ring 332, the first cover plate 31, and the first pole post 331, and will not be repeated here.

[0078] In this way, the structure formed by the first cover plate 31, the first terminal post 331, and the first fixing ring 332 can be approximately symmetrical with the structure formed by the second cover plate 32, the second terminal post 341, and the second fixing ring 342. This allows the first cover plate 31 and the second cover plate 32 to use the same manufacturing process, and the first fixing ring 332 and the second fixing ring 342 to be the same parts. This reduces the overall design and processing complexity of the cover plate assembly 30, improves the interchangeability of parts, and enhances the overall assembly efficiency of the battery pack 120 while reducing the manufacturing cost of the battery pack 120.

[0079] In some other embodiments, the second pole post assembly 34 may not include the second fixing ring 342, and the outer peripheral surface of the second pole post 341 may have two protrusions arranged axially, which clamp the second cover plate 32 to achieve relative fixation between the second pole post 341 and the second cover plate 32. In still other embodiments, the outer peripheral surface of the second pole post 341 may have one protrusion, and the cover plate assembly 30 may further include a limiting member connected to the second pole post 34 and clamping the second cover plate 32 with the protrusion; or, the second cover plate 32 may have two limiting members that clamp the protrusion on both sides of the second pole post 341 along the axial direction.

[0080] Please refer to the following: Figures 6-9The first pole post 331 includes a first column segment 3311 and a second column segment 3312 connected along the axial direction of the first pole post 331. The first column segment 3311 is annular, and the second column segment 3312 is plate-shaped. At least a portion of the second column segment 3312 is located between the first cover plate 31 and the second cover plate 32. Figure 6 and Figure 7 In the illustrated embodiment, the entire second column segment 3312 is located between the first cover plate 31 and the second cover plate 32. In other embodiments, the second column segment 3312 may also be partially located between the first cover plate 31 and the second cover plate 32.

[0081] The second electrode post 341 is welded to the second column segment 3312 to form a welded portion 30A. The welded portion 30A extends to the surface of the second column segment 3312 facing the first column segment 3311 and is located on the inner circumferential side of the first column segment 3311. Specifically, laser penetration welding can be performed on the second column segment 3312 and the second electrode post 341 from the inner cavity of the first column segment 3311 to connect the first electrode post 331 and the second electrode post 341 and make them electrically conductive. That is, a portion of the surface of the welded portion 30A forms a portion of the surface of the cover plate assembly 30, and this portion of the surface is located on the inner circumferential side of the first column segment 3311.

[0082] In this way, the welded portion 30A can be formed through penetration welding, resulting in a stronger connection between the first electrode 331 and the second electrode 341, and a lower resistivity between them, thus ensuring the reliability of the electrical connection between the first battery cell 122A and the second battery cell 122B. Furthermore, it limits the spread of welding heat and spatter, preventing damage to other components (such as the first insulating component 333, the second insulating component 343, etc.) due to heat, thereby improving the overall reliability of the cover plate assembly 30.

[0083] In some embodiments, the minimum distance L4 between the welded portion 30A and the inner circumferential surface of the first column segment 3311 in a direction perpendicular to the axial direction of the first pole post 331 satisfies: L4 ≥ 1 mm. For example, L4 can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc. This prevents the welded portion 30A from being too close to the inner circumferential surface of the first column segment 3311 during welding of the first pole post 331 and the second pole post 341, which could cause the welding heat to reduce the strength of the first column segment 3311 and consequently reduce the overall strength of the cover plate assembly 30.

[0084] Please continue reading. Figures 6-9The length H1 of the second column segment 3312 along the axial direction of the first electrode post 331 satisfies: 0.5mm ≤ H1 ≤ 2.5mm. Specifically, when the first electrode tab 10B1 is the positive electrode tab of the first battery cell 122A, the first electrode post 331 can be an aluminum structural component, and H1 can be 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, etc. When the first electrode tab 10B1 is the negative electrode tab of the first battery cell 122A, the first electrode post 331 can be a copper structural component, and H1 can satisfy: 0.5mm ≤ H1 ≤ 2.0mm, for example, H1 can be 0.5mm, 1.0mm, 1.5mm, 2.0mm, etc.

[0085] This prevents the second column segment 3312 from being too short, which would result in a weaker first pole post 331 and consequently a weaker overall strength of the cover plate assembly 30. It also prevents the second column segment 3312 from being too long, which would result in a higher power required for penetration welding and consequently a higher overall cost of the cover plate assembly 30.

[0086] In some other embodiments, the first column segment 3311 may also be a solid column, and the second column segment 3312 and the second pole post 341 may also be laser-welded from the outer peripheral surface to connect the first pole post 331 and the second pole post 341 and make them electrically conductive.

[0087] Please continue reading. Figures 6-9 The first pole post assembly 33 also includes a first insulating member 333. The first insulating member 333 is sleeved on the first pole post 331 and is located between the outer peripheral surface of the first pole post 331 and the inner peripheral surface of the first fixing ring 332. Specifically, the first ring segment 3321 and the fourth ring segment 3421 are both located between the first cover plate 31 and the second cover plate 32. The first insulating member 333 surrounds the first pole post 331. A portion of the first insulating member 333 is located between the first protrusion 331a and the inner peripheral surface of the second ring segment 3322, and a portion is clamped between the first ring segment 3321 and the first protrusion 331a along the axial direction of the first pole post 331. That is, the first ring segment 3321 transmits clamping force to the first protrusion 331a through the first insulating member 333, and a portion is located between the outer peripheral surface of the first pole post 331 and the inner peripheral surface of the first ring segment 3321. Based on this, the end face of the first insulating member 333 facing the second cover plate 32 is located between the first fixing ring 332 and the second cover plate 32.

[0088] This prevents the first terminal 331 from short-circuiting with the first cover plate 31 through contact with the first retaining ring 332. Furthermore, it increases the surface creepage distance between the first terminal 331 and the second terminal 341 via the surface of the first insulating member 333 to the first cover plate 31, thereby improving the electrical breakdown resistance of the cell assembly 122 in harsh environments such as humidity and pollution, and thus enhancing the overall reliability of the battery pack 120.

[0089] Similarly, the second pole assembly 34 includes a second insulating member 343, which is sleeved on the second pole 341 and located between the outer peripheral surface of the second pole 341 and the inner peripheral surface of the second fixing ring 342. The end face of the second insulating member 343 facing the first cover plate 31 is located between the second fixing ring 342 and the first cover plate 31. Specifically, the connection method and technical effect between the second insulating member 343 and the second pole 341 and the second fixing ring 342 can be referred to the aforementioned connection method and technical effect between the first insulating member 333 and the first pole 331 and the first fixing ring 332, and will not be repeated here.

[0090] Please continue reading 6- Figure 9 The distance L1 between the first insulating member 333 and the second insulating member 343 satisfies: L1 ≥ 0.1 mm. For example, the distance L1 between the first insulating member 333 and the second insulating member 343 can be 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.0 mm, etc. This prevents interference between the first insulating member 333 and the second insulating member 343, which could lead to a gap between the first pole post 331 and the second pole post 341, making welding between them impossible or resulting in poor welding reliability.

[0091] Please continue reading. Figures 6-9 The first electrode assembly 33 further includes a first sealing ring 334, which is sleeved on the first electrode 331 and insulated and sealed between the first electrode 331 and the third ring segment 3323. Specifically, the first sealing ring 334 is clamped and compressed between the first protrusion 331a and the third ring segment 3323 along the axial direction of the first electrode 331. In some other embodiments, a portion of the first sealing ring 334 may be clamped and compressed between the first protrusion 331a and the third ring segment 3323 along the axial direction of the first electrode 331, while another portion may be clamped and compressed between the outer peripheral surface of the first electrode 331 and the inner peripheral surface of the third ring segment 3323. In this way, the first sealing ring 334 can prevent the electrolyte in the first cell 122A from seeping out along the first electrode 331 to the outside of the first cell 122A, thereby ensuring the overall reliability of the cell assembly 122.

[0092] Similarly, the second pole post assembly 34 also includes a second sealing ring 344, which is sleeved on the second pole post 341 and provides an insulating seal between the second pole post 341 and the sixth ring segment 3423. The connection method and technical effects between the second sealing ring 344 and the second pole post 341 and the second fixing ring 342 can be referenced to the connection method and technical effects between the first sealing ring 334 and the first pole post 331 and the first fixing ring 332, and will not be elaborated further here.

[0093] Please continue reading. Figures 6-9 The insulating component 35 includes a sixth insulating element 351 and a seventh insulating element 352. The sixth insulating element 351 is stacked on the side of the first cover plate 31 opposite to the second cover plate 32 and connected to the first cover plate 31. The first pole post 331 also passes through the sixth insulating element 351. Specifically, the sixth insulating element 351 can be connected to the first cover plate 31 by means of snap-fit, bonding, welding, etc.

[0094] In this way, by setting the sixth insulating element 351, it is possible to prevent the first tab 10B1 and / or the third tab inside the first cell 122A from short-circuiting with the first cover plate 31.

[0095] The seventh insulating element 352 is stacked on the side of the second cover plate 32 opposite to the first cover plate 31 and connected to the second cover plate 32. The second pole post 341 also passes through the seventh insulating element 352. Specifically, the seventh insulating element 352 can be connected to the second cover plate 32 by means of snap-fit, bonding, welding, etc. The technical effect of setting the seventh insulating element 352 can be compared with the technical effect of setting the sixth insulating element 351.

[0096] Please refer to the following: Figure 5 and Figure 10 , Figure 10 for Figure 5 Another cross-sectional view of the cover plate assembly 30 at the BB line is shown. Figure 10 The illustrated embodiments and Figures 6-9 The difference in the embodiment shown is that the first pole post assembly 33 further includes a third insulating member 335, which is sleeved on the first pole post 331 and located on the side of the first fixing ring 332 facing the second cover plate 32. The third insulating member 335 is in contact with the first insulating member 333 and the first fixing ring 332.

[0097] This can further increase the surface creepage distance between the first terminal 331 and the second terminal 341 via the surface of the third insulating member 335 to the first cover plate 31, thereby further improving the electrical breakdown resistance of the battery cell assembly 122 in harsh environments such as humidity and pollution.

[0098] Similarly, the second pole post assembly 34 also includes a fourth insulating member 345. The fourth insulating member 345 is sleeved on the second pole post 341 and located on the side of the second fixing ring 342 facing the first cover plate 31. The fourth insulating member 345 is in contact with both the second insulating member 343 and the second fixing ring 342. The technical effect of providing the fourth insulating member 345 can be compared with the technical effect of providing the third insulating member 335, and will not be repeated here.

[0099] Based on this, the third insulating element 335 and the fourth insulating element 345 are spaced apart. Specifically, the distance between the third insulating element 335 and the fourth insulating element 345 can be greater than or equal to 0.1 mm. For possible values ​​of the distance between the third insulating element 335 and the fourth insulating element 345 and their technical effects, please refer to... Figure 6 The values ​​of the distance between the first insulating member 333 and the second insulating member 343 in the illustrated embodiment, as well as the technical effects, will not be elaborated here.

[0100] Please refer to the following: Figure 5 and Figure 11 , Figure 11 for Figure 5 Another cross-sectional view of the cover plate assembly 30 at the BB line. Figure 11 The illustrated embodiments and Figure 6 The difference in the illustrated embodiment is that the second pole post 341 includes a third pole segment 3411 and a fourth pole segment 3412 that are axially connected and made of different materials. The fourth pole segment 3412 is made of the same material as the first pole post 331. A portion of the fourth pole segment 3412 and a portion of the second pole segment 3312 form a welded portion 30A.

[0101] In this way, the fourth column segment 3412 and the first pole column 331 are made of the same material, and the heat during welding is concentrated at the interface of the same material. After welding, there will be no residual shear stress caused by the difference in shrinkage, resulting in better welding reliability. In addition, it can also reduce the design difficulty of welding process parameters.

[0102] Specifically, when the first tab 10B1 is the positive tab of the first battery cell 122A, the first terminal post 331 can be an aluminum structure. Correspondingly, the second tab 10D1 is the negative tab of the second battery cell 122B. The third segment 3411 of the second terminal post 341 is a copper structure, and the fourth segment 3412 is an aluminum structure. The third segment 3411 and the fourth segment 3412 can be connected by friction welding, explosive welding, flash welding, butt rolling composite welding, ultrasonic welding, etc. Based on this, the length L3 of the fourth segment 3412 along the axial direction of the second terminal post 341 satisfies: L3 ≥ 1mm. For example, L3 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0103] In some other embodiments, when the first tab 10B1 is the negative tab of the first cell 122A, the first terminal post 331 can be a copper structure. Correspondingly, the second tab 10D1 is the negative tab of the second cell 122B, the third segment 3411 of the second terminal post 341 is an aluminum structure, and the fourth segment 3412 is a copper structure. Based on this, the length L3 of the fourth segment 3412 along the axial direction of the second terminal post 341 satisfies: L3 ≥ 0.8 mm. For example, L3 can be 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc.

[0104] This prevents the fourth column segment 3412 from being too short, which could easily cause the welded section 30A to be welded through, resulting in the electrolyte coming into contact with both the aluminum and copper structural parts at the same time and forming a galvanic cell, thus making the cell assembly 122 prone to corrosion.

[0105] Please continue reading. Figure 5 and Figure 11 A portion of the aforementioned second protrusion 341a is formed on the third column segment 3411, and another portion is formed on the fourth column segment 3412. In this way, the clamping force of the fourth ring segment 3421 and the sixth ring segment 3423 can prevent the connection between the third column segment 3411 and the fourth column segment 3412 from failing under the action of vibration and external impact, thereby improving the reliability of the second pole post 341 and thus improving the overall reliability of the cover plate assembly 30.

[0106] Based on the above, the interface between the third column segment 3411 and the fourth column segment 3412 is located between the first sealing ring 334 and the second sealing ring 344. In this way, the second sealing ring 344 can prevent the electrolyte in the second cell 122B from penetrating into the cell assembly 122, which would form a galvanic cell in contact with both the third column segment 3411 and the fourth column segment 3412, thus preventing easy corrosion of the cell assembly 122.

[0107] Please refer to the following: Figure 5 and Figure 12 , Figure 12 for Figure 5 The diagram shows another cross-sectional structure of the cover plate assembly 30 at line BB. Figure 12 The illustrated embodiments and Figure 6 The difference in the illustrated embodiment is that the end face of the second pole post 341 facing away from the first pole post 331 has a first groove 341b, and the orthographic projection of the welded portion 30A in the first reference plane overlaps with the orthographic projection of the first groove 341b in the first reference plane. The first reference plane is perpendicular to the axial direction of the second pole post 341. Specifically, the orthographic projection of the welded portion 30A in the first reference plane can be located within the orthographic projection of the first groove 341b in the first reference plane.

[0108] This reduces the weight of the second pole post 341, which in turn helps to lighten the overall weight of the cover plate assembly 30.

[0109] Based on this, when the second terminal post 341 includes a third terminal segment 3411 and a fourth terminal segment 3412, the first groove 341b is formed in the third terminal segment 3411. In this way, it is possible to prevent the electrolyte from simultaneously contacting the third terminal segment 3411 and the fourth terminal segment 3412 to form a galvanic cell, which would make the cell assembly 122 prone to corrosion.

[0110] In some embodiments, the distance L2 between the bottom wall of the first groove 341b and the fourth column segment 3412 satisfies: L2≥0.5mm. For example, the distance L2 between the bottom wall of the first groove 341b and the fourth column segment 3412 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, etc.

[0111] This prevents the distance between the first groove 341b and the fourth column segment 3412 from being too small, which would result in the third column segment 3411 having low strength. Under the action of welding heat during the welding of the first pole post 331 and the second pole post 341, the third column segment 3411 is prone to deformation and separation from the fourth column segment 3412, leading to poor overall reliability of the cover plate assembly 30.

[0112] In some other embodiments, the second pole post 341 may also be a one-piece molded part of the same material.

[0113] Please see Figure 13 , Figure 13 for Figure 2 Another cross-sectional view of the cover assembly 30 of the battery pack 120 shown. Figure 13 The illustrated embodiments and Figure 6 The difference in the illustrated embodiment is that the insulating assembly further includes a fifth insulating element 353, which is stacked between the first cover plate 31 and the second cover plate 32 and connected to at least one of the first cover plate 31 and the second cover plate 32. Specifically, the fifth insulating element 353 can be connected to the first cover plate 31 and / or the second cover plate 32 by bonding, welding, or injection molding. This further improves the insulation reliability between the first cover plate 31 and the second cover plate 32.

[0114] Figure 10 In the illustrated embodiment, the thickness of the fifth insulating member 353 is the same as the distance between the first cover plate 31 and the second cover plate 32. Thus, the fifth insulating member 353 also provides support for the first cover plate 31 and the second cover plate 32, preventing deformation of the cell assembly 122 under external force. In other embodiments, the thickness of the fifth insulating member 353 may be less than the distance between the first cover plate 31 and the second cover plate 32.

[0115] The aforementioned cover plate assembly 30 can be manufactured using the following method.

[0116] First, an initial first fixing ring, a first pole post 331, a first sealing ring 334, and a first insulating member 333 are provided. After the first pole post 331 passes through the first insulating member 333, the first sealing ring 334, and the initial first fixing ring, a portion of the initial first fixing ring is bent using a flanging process to form a first fixing ring 332, thereby forming the first pole post assembly 33. Specifically, the structure of the first pole post assembly 33 can be referred to the foregoing. The initial first fixing ring may include a third ring segment 3323, a second ring segment 3322, and an initial first ring segment connected sequentially. The extension direction of the initial first ring segment is the same as the extension direction of the second ring segment 3322, and the initial first ring segment is used for bending to form the first ring segment 3321.

[0117] Next, a first cover plate 31 is provided, and the first pole post assembly 33 is inserted through the first through hole 31a of the first cover plate 31, thereby fixing the first retaining ring 332 to the first cover plate 31. Specifically, the first retaining ring 332 can be welded to the first cover plate 31, and the connection structure between the first pole post assembly 33 and the first cover plate 31 can refer to the above description.

[0118] Next, a sixth insulating element 351 is provided and connected to the first cover plate 31. The connection structure between the sixth insulating element 351, the first cover plate 31, and the first pole post 331 can be referred to the foregoing.

[0119] Next, an initial second fixing ring, a second pole post 341, a second sealing ring 344, and a second insulating member 343 are provided. After the second pole post 341 passes through the second insulating member 343, the second sealing ring 344, and the initial second fixing ring, a portion of the initial second fixing ring is bent using a flanging process to form a second fixing ring 342, thereby forming the second pole post assembly 34. Specifically, the structure of the second pole post assembly 34 can be referred to the foregoing. The initial second fixing ring may include a sixth ring segment 3423, a fifth ring segment 3422, and an initial fourth ring segment connected sequentially. The extension direction of the initial fourth ring segment is the same as the extension direction of the fifth ring segment 3422, and the initial fourth ring segment is used to bend to form the fourth ring segment 3421.

[0120] Next, a second cover plate 32 is provided, and the second pole post assembly 34 is inserted through the second through hole 32a of the second cover plate 32, thereby fixing the second retaining ring 342 to the second cover plate 32. Specifically, the second retaining ring 342 can be welded to the second cover plate 32, and the connection structure between the second pole post assembly 34 and the second cover plate 32 can refer to the above description.

[0121] Next, a seventh insulating element 352 is provided and connected to the second cover plate 32. The connection structure between the seventh insulating element 352, the second cover plate 32, and the second pole post 341 can be referred to the above.

[0122] Next, the first pole piece 331 and the second pole piece 341 are aligned, and the second pole piece 3312 and the second pole piece 341 are welded together to connect the first pole piece 331 and the second pole piece 341, forming a cover plate assembly 30. Specifically, the second pole piece 3312 and the second pole piece 341 can be welded through the inner cavity of the first pole piece 3311 to form a welded portion 30A, thereby connecting the first pole piece 331 and the second pole piece 341.

[0123] Next, a fifth insulating element 353 is stacked between the first cover plate 31 and the second cover plate 32, and the fifth insulating element 353 is connected to the first cover plate 31 and / or the second cover plate 32 to form another cover plate assembly 30. Specifically, the fifth insulating element 353 can be connected to the first cover plate 31 and / or the second cover plate 32 by injection molding, bonding, welding, or other methods.

[0124] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A cover plate assembly, characterized in that, include: A first cover plate, the first cover plate having a first through hole; The first pole post has a first protrusion on its outer peripheral surface; The first fixing ring passes through the first through hole and is fixedly connected to the first cover plate; the first fixing ring is sleeved on the first pole post and includes a first ring segment, a second ring segment and a third ring segment connected sequentially along the axial direction, the first ring segment and the third ring segment clamping the first protrusion from both sides of the axial direction of the first pole post; A second cover plate is stacked on top of and spaced apart from the first cover plate, and the second cover plate has a second through hole; The second pole post passes through the second through hole and is fixed relative to the second cover plate; the second pole post is welded to the first pole post; The first terminal is used to connect to the first tab of the first battery cell, and the second terminal is used to connect to the second tab of the second battery cell. The polarity of the first tab is opposite to that of the second tab.

2. The cover plate assembly according to claim 1, characterized in that, The outer peripheral surface of the second pole post has a second protrusion; The cover plate assembly further includes a second fixing ring, which passes through the second through hole and is fixedly connected to the second cover plate; the second fixing ring is sleeved on the second pole post and includes a fourth ring segment, a fifth ring segment and a sixth ring segment connected sequentially along the axial direction, wherein the fourth ring segment and the sixth ring segment clamp the second protrusion from both sides of the second pole post along the axial direction.

3. The cover plate assembly according to claim 2, characterized in that, The cover plate assembly also includes: A first insulating element is sleeved on the first pole post and located between the outer peripheral surface of the first pole post and the inner peripheral surface of the first fixing ring; the end face of the first insulating element facing the second cover plate is located between the first fixing ring and the second cover plate; and / or, The second insulating element is sleeved on the second pole post and located between the outer peripheral surface of the second pole post and the inner peripheral surface of the second fixing ring. The end face of the second insulating element facing the first cover plate is located between the second fixing ring and the first cover plate.

4. The cover plate assembly according to claim 3, characterized in that, The distance L1 between the first insulating element and the second insulating element satisfies: L1 ≥ 0.1 mm; and / or, The cover plate assembly further includes a third insulating member and a fourth insulating member. The third insulating member is sleeved on the first pole post and located on the side of the first fixing ring facing the second cover plate. The third insulating member is in contact with both the first fixing ring and the first insulating member. The fourth insulating member is sleeved on the second pole post and located on the side of the second fixing ring facing the first cover plate. The fourth insulating member is spaced apart from the third insulating member and is in contact with both the second fixing ring and the second insulating member.

5. The cover plate assembly according to any one of claims 2-4, characterized in that, The first electrode post includes a first column segment and a second column segment connected together. The first column segment is annular, and the second column segment is plate-shaped. The second column segment is welded to the second electrode post to form a welded portion, which is located on the inner circumferential side of the first column segment; and / or, The cover plate assembly further includes a fifth insulating element, which is stacked between the first cover plate and the second cover plate and is connected to at least one of the first cover plate and the second cover plate.

6. The cover plate assembly according to claim 5, characterized in that, The second pole post includes a third pole segment and a fourth pole segment that are connected and made of different materials. The fourth pole segment is made of the same material as the first pole post, and the fourth pole segment is welded to the first pole post to form the welded portion; and / or, The end face of the second electrode post facing away from the first electrode post has a first groove, and the orthographic projection of the welded portion in a first plane overlaps with the orthographic projection of the first groove in the first plane, wherein the first plane is perpendicular to the axial direction of the second electrode post; and / or, The length H1 of the second column segment along the axial direction of the first pole column satisfies: 0.5mm≤H1≤2.5mm.

7. The cover plate assembly according to claim 6, characterized in that, The first groove is formed in the third column segment, and the distance L2 between the bottom wall of the first groove and the fourth column segment satisfies: L2 ≥ 0.5 mm; and / or, A portion of the second protrusion is formed in the third column segment, and another portion is formed in the fourth column segment.

8. The cover plate assembly according to claim 6, characterized in that, Both the first ring segment and the fourth ring segment are located between the first cover plate and the second cover plate; The cover plate assembly also includes: The first sealing ring is sleeved on the first pole post and is insulated and sealed between the first pole post and the third ring segment; The second sealing ring is sleeved on the second pole post and is insulated and sealed between the second pole post and the sixth ring segment; wherein the interface between the third column segment and the fourth column segment is located between the second sealing ring and the first sealing ring.

9. A battery cell assembly, characterized in that, The battery includes a first battery cell and a second battery cell, which are connected by a cover plate assembly, wherein the cover plate assembly is any one of claims 1-8; wherein, The first battery cell includes a first tab and a first cover plate. The first tab is located on the side of the first cover plate opposite to the second cover plate and is connected to the first terminal post. The second cell includes a second tab and a second cover plate. The second tab is located on the side of the second cover plate opposite to the first cover plate and is connected to the second terminal post. The polarity of the second tab is opposite to that of the first tab.

10. A battery pack, characterized in that, include: At least one battery cell assembly, said battery cell assembly being the battery cell assembly of claim 9.

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