Cover plate assembly and battery

Abstract

Disclosed are a cover plate assembly and a battery. The cover plate assembly comprises a cap and a connection assembly. The connection assembly comprises a connection piece, and the material of the connection piece being aluminum; the cap is disposed on the connection piece, and the cap comprises a core material and an outer layer located outside the core material, the core material being welded to the connection piece by means of the outer layer; the material of the core material includes copper, and the material of the outer layer includes nickel.

Description

Cover plate assembly and battery

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 18, 2023, with application number 202311750197.6. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a cover assembly and a battery. Background Art

[0003] In related technologies, the battery top cover assembly is an important component of the battery. The battery top cover assembly is mainly assembled from the top cover, explosion-proof plate, connecting plate, sealing rubber ring and insulating rubber ring. The top cover is made of metal and acts as an electrode for conductivity in cylindrical batteries, supporting the production and assembly process. Currently, the connection between the explosion-proof plate and the top cover is generally welded, using laser energy to achieve the effect of hot-melt welding from the surface of the top cover to the explosion-proof aluminum plate. The existing top cover is mostly made of steel with a large internal resistance. The explosion-proof plate and the top cover are made of different materials, making welding difficult. SUMMARY OF THE INVENTION

[0004] The present application provides a cover assembly and a battery to solve the above technical problems.

[0005] In a first aspect, the present application provides a cover plate assembly, comprising:

[0006] A connecting assembly, comprising a connecting piece, wherein the connecting piece is made of aluminum; and

[0007] A top cover is provided on the connecting piece, the top cover comprises a core material and an outer layer located outside the core material, the core material is welded to the connecting piece through the outer layer, the material of the core material comprises copper, and the material of the outer layer comprises nickel.

[0008] In a second aspect, the present application further provides a battery, comprising:

[0009] a housing, wherein a cavity is formed in the housing;

[0010] a winding core disposed in the housing; and

[0011] A cover plate assembly, wherein the cover plate assembly is arranged on the winding core, the cover plate assembly includes a top cover and a connecting assembly, the connecting assembly is connected to the winding core, the connecting assembly includes a connecting piece, the material of the connecting piece is aluminum; the top cover is arranged on the connecting piece, the top cover includes a core material and an outer layer located outside the core material, the core material is welded to the connecting piece through the outer layer, the material of the core material includes copper, and the material of the outer layer includes nickel. Beneficial effects

[0012] The beneficial effects of the present application are as follows: the cover plate assembly provided by the present application has a top cover as an electrode, one end of the connecting assembly is connected to the top cover, and the other end is connected to the winding core. The core material of the top cover is made of copper, which has good electrical conductivity, low resistance, low price, and low energy consumption. The connecting piece is connected to the top cover to transmit current. The connecting piece is made of aluminum. When thermal runaway occurs, it can break quickly to disconnect the top cover from the winding core, and the resistance of aluminum is even lower. The core material is copper, and the outer layer is made of nickel. Nickel has low laser reflectivity for laser welding, while copper has high laser reflectivity for laser welding. An outer layer is provided on the outer surface of the core material so that nickel is wrapped around the outer surface of the copper. Since the reflectivity of nickel to laser is lower than that of copper to laser, a top cover with nickel wrapped around the outside of copper can improve the machinability of the entire top cover compared to a pure copper cover, thereby reducing the difficulty of welding the top cover and the connecting piece. At the same time, the outer layer is provided on the outside of the core material, which can protect the core material, prevent the core material from being corroded, and increase the service life of the cover plate assembly.

[0013] The battery provided in the present application adopts the above-mentioned cover plate assembly, the top cover serves as an electrode, one end of the connecting assembly is connected to the top cover, and the other end is connected to the winding core. The core material of the top cover is made of copper. Copper has good electrical conductivity, low resistance, is cheap, and consumes less energy. The connecting piece is connected to the top cover to transmit current. The connecting piece is made of aluminum. When thermal runaway occurs, it can break quickly to disconnect the top cover from the winding core, and the resistance of aluminum is even lower. The core material is copper, and the outer layer is made of nickel. Nickel has low laser reflectivity for laser welding, while copper has high laser reflectivity for laser welding. An outer layer is provided on the outer surface of the core material so that nickel is wrapped around the outer surface of the copper. Since the reflectivity of nickel to laser is lower than that of copper to laser, a top cover with nickel wrapped around the outside of copper can improve the machinability of the entire top cover compared to a pure copper cover, thereby reducing the difficulty of welding the top cover and the connecting piece. At the same time, the outer layer is provided on the outside of the core material, which can protect the core material, prevent the core material from being corroded, and increase the service life of the cover plate assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 is a structural schematic diagram of an embodiment of a cover plate assembly provided by the present application;

[0015] FIG2 is a bottom plan view of FIG1 ;

[0016] FIG3 is a partial cross-sectional view of the top cover in FIG1 ;

[0017] FIG4 is a schematic structural diagram of the orifice plate in FIG1 ;

[0018] FIG5 is an enlarged schematic diagram of A in FIG4 ;

[0019] FIG6 is a schematic structural diagram of an embodiment of a battery provided by the present application;

[0020] FIG7 is a schematic structural diagram of the battery in FIG6 in another state.

[0021] Description of reference numerals:

[0022] 1000, battery; 100, cover assembly; 101, connection assembly; 102, connection piece; 103, top cover; 104, core material; 105, outer layer; 106, orifice plate; 107, first connection part; 108, second connection part; 109, first gap; 110, first notch; 111, welding part; 112, first side; 113, second side; 114, sealing member; 115, first extension part; 116, first connection section; 117, second connection section; 118, second gap; 119, second notch; 120, insulating member; 200, shell; 201, second extension part; 300, winding core. Modes for Carrying Out the Invention

[0023] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0024] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0025] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0026] In related technologies, the battery top cover assembly is an important component of the battery. The battery top cover assembly is mainly assembled from the top cover, explosion-proof plate, connecting plate, sealing rubber ring and insulating rubber ring. The top cover is made of metal and acts as an electrode for conductivity in cylindrical batteries, supporting the production and assembly process. Currently, the connection between the explosion-proof plate and the top cover is generally welded, using laser energy to achieve the effect of hot-melt welding from the surface of the top cover to the explosion-proof aluminum plate. The existing top cover is mostly made of steel with a large internal resistance. The explosion-proof plate and the top cover are made of different materials, making welding difficult.

[0027] In view of this, the present application proposes a cover assembly 100. Figures 1 to 5 are structural schematic diagrams of an embodiment of the cover assembly 100 provided by the present application. The cover assembly 100 provided by the present application has a small internal resistance and is welded to the top cover 103. The welding position adopts a plating process, the welding difficulty is low, and the connection strength is high. The cover assembly 100 will be described in detail in conjunction with the main drawings below.

[0028] Please refer to Figure 1, the cover plate assembly 100 includes a top cover 103 and a connecting assembly 101; the connecting assembly 101 includes a connecting piece 102, and the material of the connecting piece 102 is aluminum; the top cover 103 is arranged on the connecting piece 102, and the top cover 103 includes a core material 104 and an outer layer 105 located outside the core material 104, the core material 104 is welded to the connecting piece 102 through the outer layer 105, the material of the core material 104 includes copper, and the material of the outer layer 105 includes nickel.

[0029] In the technical solution of the present application, the top cover 103 serves as an electrode, one end of the connecting component 101 is connected to the top cover 103, and the other end is connected to the winding core 300. The material of the core material 104 of the top cover 103 is copper. Copper has good electrical conductivity, low resistance, low price, and low energy consumption. The connecting piece 102 is connected to the top cover 103 to transmit current. The material of the connecting piece 102 is aluminum. When thermal runaway occurs, it can break quickly to disconnect the top cover 103 from the winding core 300, and the resistance of aluminum is small. The material of the core material 104 is copper, and the material of the outer layer 105 is nickel. Nickel is sensitive to thermal runaway. The laser reflectivity of optical welding is relatively small, while the laser reflectivity of copper to laser welding is relatively large. The outer layer 105 is arranged on the outer surface of the core material 104, so that nickel is wrapped on the outer surface of the copper. Since the reflectivity of nickel to laser is lower than that of copper to laser, the top cover 103 with nickel wrapped on the outside of copper can improve the machinability of the entire top cover 103 compared to the pure copper cover plate, thereby reducing the difficulty of welding the top cover 103 and the connecting piece 102. At the same time, the outer layer 105 is arranged on the outside of the core material 104, which can protect the core material 104, avoid the core material 104 from being corroded, and improve the service life of the cover plate assembly 100.

[0030] It should be noted that, in this embodiment, the connecting component 101 is provided below the top cover 103 , one end of the connecting component 101 is connected to the top cover 103 , and the other end is connected to the winding core 300 to transmit current.

[0031] More specifically, the top cover 103 and the connecting piece 102 are connected by welding, and the core material 104 of the top cover 103 is made of copper. Copper has a high reflection rate for laser welding, and the welding process is complicated and difficult. Nickel has a low reflection rate for laser welding. Therefore, the top cover 103 with nickel wrapped around the outside of copper can improve the machinability of the entire top cover 103 compared to the pure copper cover plate. Specifically, in this embodiment, please refer to Figure 3, the outer layer 105 is wrapped around the outside of the core material 104. On the one hand, the material of the outer side is nickel, and nickel has a low reflection rate for laser welding. A layer of nickel is plated on the outside of the copper, making it easier to weld the top cover 103 to the connecting piece 102. At the same time, the outer layer 105 is wrapped around the outer surface of the core material 104, which can also protect the core material 104, prevent the core material 104 from being exposed to the air and being oxidized and corroded, thereby improving the service life of the top cover 103.

[0032] Specifically, in actual application, it is necessary to consider the thickness of the core material 104 and the thickness of the outer layer 105. In this embodiment, the thickness of the core material 104 is D1, and the thickness of the outer layer 105 is D2. After repeated testing and research by the applicant, it is concluded that when D1 ≥ 0.1 mm and D2 ≥ 3 μm, the connection strength of the connecting piece 102 meets the requirements and the resistance is correspondingly small.

[0033] It should be noted that, in actual application, it is necessary to consider not only the resistance of the connecting piece 102, but also the connection strength of the connecting piece 102, and the occupied space. First, it is necessary to ensure the connection strength of the connecting piece 102. If the thickness of the connecting piece 102 is thin, the connection strength will be weak, and the connecting piece 102 will be easy to break. If the thickness of the connecting piece 102 is thick, the space occupied by the connecting piece 102 will increase, resulting in an increase in the size of the entire top cover 103; further, in this embodiment, 0.4mm≤D1≤0.8mm, 4μm≤D2≤9μm. Specifically, the thickness of the core material 104 can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, or 0.8mm; the thickness of the outer layer 105 can be 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, or 9μm, and the selection can be made according to actual conditions.

[0034] Another function of the connecting component 101 is to avoid thermal runaway. When the temperature inside the battery 1000 is too high or the pressure is too high, the connecting component 101 can break and disconnect the top cover 103 from the winding core 300. Specifically, in this embodiment, the connecting component 101 also includes a perforated plate 106, which is connected to the side of the connecting piece 102 away from the top cover 103; the perforated plate 106 is connected to the winding core 300. During the actual current transmission process, The winding core 300 transmits the current to the orifice plate 106, and the orifice plate 106 is welded to the connecting piece 102. The orifice plate 106 transmits the current to the connecting piece 102, and the connecting piece 102 then transmits the current to the top cover 103. A second notch 119 is formed on the orifice plate 106. When the internal pressure of the battery 1000 is too high or the temperature is too high, the orifice plate 106 breaks at the position of the second notch 119, disconnecting the internal connection of the battery 1000 to avoid thermal runaway, etc.

[0035] In this embodiment, please refer to Figures 4 and 5. The connecting piece 102 includes a first connecting portion 107 and a second connecting portion 108 connected to the periphery of the first connecting portion 107. The second connecting portion 108 is connected to the top cover 103. It should be noted that, considering the actual application scenarios and cost saving issues, when electroplating the outer layer 105 on the core material 104, it is possible to only consider plating at the welding position, that is, the outer layer 105 only covers part of the core material 104 (the position where welding is required). In this way, the thickness of the top cover 103 can be reduced to a certain extent without affecting the laser welding. However, considering the electroplating process and the service life of the top cover 103, as a preferred embodiment, please refer to Figure 2, the outer layer 105 completely wraps the outside of the core material 104, isolates the core material 104 from the outside world, prevents the core material 104 from being corroded, and improves the service life of the top cover 103.

[0036] Furthermore, the first connection portion 107 is connected to the orifice plate 106, and the first connection portion 107 is recessed in a direction away from the top cover 103 to form a first gap 109 between the top cover 103. The function of the first gap 109 is to isolate the first connection portion 107 from the top cover 103, so that the top cover 103 is connected only to the second connection portion 108, and the first connection portion 107 is connected only to the orifice plate 106. When the battery 1000 experiences thermal runaway, the orifice plate 106 breaks, and the orifice plate 106 is disconnected from the first connection portion 107, that is, the orifice plate 106 is separated from the first connection portion 107, and the current transmission is interrupted.

[0037] Furthermore, a first notch 110 is formed on the second connecting portion 108 . The opening of the first notch 110 is arranged toward the top cover 103 . In the direction from the second connecting portion 108 toward the orifice plate 106 , the width of the first notch 110 is gradually reduced. The function of the first notch 110 is to disconnect the first connecting portion 107 from the second connecting portion 108, thereby providing a double protection. Specifically, when thermal runaway occurs in the battery 1000, the orifice plate 106 breaks at the position of the second notch 119, and the orifice plate 106 is disconnected from the connecting piece 102 (that is, the cover plate assembly 100 is disconnected from the winding core 300). At the same time, the second connecting portion 108 breaks at the first notch 110, and the second connecting portion 108 is disconnected from the first connecting portion 107. The first notch 110 provides a double protection. When the orifice plate 106 does not break due to special reasons, the second connecting portion 108 breaks at the position of the first notch 110, which can also cut off the power supply of the entire battery 1000 and avoid thermal runaway. At the same time, when the orifice plate 106 breaks, if a lap short circuit occurs due to special reasons, the second connecting portion 108 breaks at the first notch 110, which can also cut off the power supply of the entire battery 1000.

[0038] Furthermore, referring to FIG5 , the second connecting portion 108 further includes a first connecting segment 116 and a second connecting segment 117 arranged around the first connecting segment 116. The first connecting segment 116 is connected to the first connecting segment 107, and the second connecting segment 117 is connected to the top cover 103. The first notch 110 is formed on the first connecting segment 116. Specifically, a second gap 118 is formed between the first connecting segment 116 and the second connecting segment 117 (i.e., the second connecting portion 108) and the orifice plate 106. The second gap 118 is used to connect the second connecting portion 108 to the orifice plate 106. 06 is spaced apart, so that the orifice plate 106 is only connected to the first connecting portion 107. It should be noted that the position where the orifice plate 106 is connected to the first connecting portion 107 is the second connection point, and the second notch 119 is formed at the second connection point. When the battery 1000 has thermal runaway, the orifice plate 106 breaks from the second notch 119. Since the orifice plate 106 is only connected to the first connecting portion 107 and not to the second connecting segment 117, and there is a second gap 118 between the orifice plate 106 and the second connecting portion 108, the possibility of short circuit between the orifice plate 106 and the second connecting portion 108 is reduced.

[0039] Furthermore, in this embodiment, the first notch 110 is formed on the first connecting section 116, and the first connecting section 116 and the top cover 103 are spaced apart (that is, there is no connection relationship between the first connecting section 116 and the top cover 103), and the second connecting section 117 is connected to the top cover 103. When the battery 1000 has thermal runaway, the second connecting portion 108 breaks at the first connecting section 116, thereby disconnecting the connection between the second connecting portion 108 and the first connecting portion 107, and thereby disconnecting the orifice plate 106 from the top cover 103.

[0040] More specifically, considering the stability of the structural connection, the cover plate assembly 100 further includes an insulating member 120, which is disposed within the second gap 118. The insulating member 120 can, on the one hand, isolate the orifice plate 106 from the second connecting portion 108, thereby preventing the orifice plate 106 from short-circuiting with the second connecting portion 108 after a break. Furthermore, the insulating member 120 can provide support by filling the second gap 118, thereby maintaining a force balance between the orifice plate 106 and the second connecting portion 108.

[0041] Furthermore, a second notch 119 is formed on the orifice plate 106. The opening of the second notch 119 is arranged toward the first connecting portion 107. The width of the second notch 119 is reduced in the direction from the first connecting portion 107 toward the orifice plate 106. Specifically, the orifice plate 106 includes a third connecting segment and a fourth connecting segment arranged around the third connecting segment. The third connecting segment is connected to the first connecting portion 107. The second notch 119 is formed on the third connecting segment. This arrangement has two purposes: one is to protect the second notch 119 through the first connecting portion 107 to prevent the orifice plate 106 from breaking prematurely at the second notch 119 due to uneven force during the welding process; the other purpose is to allow the orifice plate 106 to break at a characteristic position (the third connecting segment) to avoid flying chips generated during the breaking process from contacting other parts and causing a short circuit.

[0042] Referring to Figures 1 and 2 , a plurality of welding portions 111 are formed on an end surface of the top cover 103 facing away from the connecting piece 102. The plurality of welding portions 111 surround the center of the connecting piece 102. In this embodiment, the plurality of welding portions 111 are disposed at the edge of the top cover 103, spaced apart, and the distance between each adjacent two welding portions 111 is the same. Thus, the plurality of welding portions 111 are arranged equidistantly around the top cover 103, thereby improving the torque resistance of the top cover 103.

[0043] Specifically, in this embodiment, each of the welding portions 111 has a first side 112 and a second side 113 that are relatively arranged, and the second side 113 is arranged close to the edge of the connecting piece 102. The distance between the first side 112 and the second side 113 is L1, and the shortest distance between the first side 112 and the center of the connecting piece 102 is L2. The size and position of each of the welding portions 111 can be defined by L1 and L2. In actual application, the position of the first side 112 is first determined according to L2. When the first side 112 is determined, the position of the second side 113 is determined according to L1. In this way, the specific position of the welding portion 111 can be determined. More specifically, 0.1mm≤L1≤0.3mm, 6.8mm≤L2<8.7mm. The distance between the first side 112 and the second side 113 can be 0.1mm, 0.12mm, 0.14mm, 0.15mm, 0.16mm, 0.18mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, or 0.30mm; the shortest distance between the first side 112 and the center of the connecting piece 102 can be 6.80mm, 6.85mm, 6.90mm, 6.92mm, 6.95mm, 6.99mm, 7.01mm, 7.05mm, 7.10mm, 7.15mm, or 7.20mm. further, in a preferred embodiment, the distance between the first side 112 and the center of the connecting piece 102 is 8.5 mm, and the distance between the first side 112 and the second side 113 is 0.25 mm.

[0044] Furthermore, the curvature of each welding portion 111 is α, wherein 35°≤α≤45°. Specifically, the curvature of each welding portion 111 can be 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, or 45°.

[0045] To ensure the strength of the battery 1000, the housing 200 of the battery 1000 is generally made of metal, which is often a conductive material. Therefore, the cover assembly 100 further includes a seal 114, which surrounds the outside of the top cover 103 and the connecting assembly 101. The seal 114 is configured to isolate the top cover 103 and the connecting assembly 101 from the housing 200, thereby preventing direct contact between the top cover 103 or the connecting assembly 101 and the housing 200 and causing a short circuit. In this embodiment, the seal 114 is preferably a sealing rubber ring.

[0046] Please refer to Figures 1 and 2, wherein the sealing member in Figure 1 is in an undeployed state, and the plurality of welding portions 111 are formed at the end of the top cover 103 away from the connecting piece 102, that is, the plurality of welding portions 111 are located on the outside. The plurality of welding portions 111 are exposed to the outside for a long time, which will cause the welding points on the plurality of welding portions 111 to be oxidized and corroded. Therefore, in this embodiment, the end of the sealing member 114 close to the top cover 103 is folded toward the top cover 103 to form a first extension portion 115, and the first extension portion 115 is covered on the plurality of welding portions 111. The orthographic projection of the first extension portion 115 on the top cover 103 covers the plurality of welding portions 111, thereby isolating the plurality of welding portions 111 from the outside and preventing the welding points on the plurality of welding portions 111 from being oxidized.

[0047] It should be noted that the length of the first extension portion 115 is related to the size and position of the multiple welding portions 111. It is necessary to consider both being able to fully cover the multiple welding portions 111 to avoid exposure of the welds on the multiple welding portions 111, and to avoid the first extension portion 115 being too long, which affects the current transmission of the top cover 103. Specifically, in this embodiment, the first extension portion 115 has a first end facing the center of the top cover 103, and the distance from the first end to the center of the top cover 103 is L3, wherein 13.6mm≤2L3≤14.4mm. After repeated research and testing by the applicant, it is concluded that L3 must satisfy 13.6mm≤2L3≤14.4mm. More specifically, the length of the first extension portion 115 is 13.6 mm, 13.65 mm, 13.7 mm, 13.75 mm, 13.8 mm, 13.85 mm, 13.9 mm, 13.95 mm, 14.0 mm, 14.05 mm, 14.1 mm, 14.15 mm, 14.2 mm, 14.25 mm, 14.3 mm, 14.35 mm, or 14.4 mm. As a preferred embodiment, the length of the first extension portion 115 is 14 mm.

[0048] The present application also proposes a battery 1000, please refer to Figures 6 and 7, the battery 1000 includes a shell 200, a winding core 300 and a cover assembly 100; a cavity is formed in the shell 200; the winding core 300 is arranged in the shell 200; the cover assembly 100 is covered on the winding core 300, and the connecting assembly 101 is connected to the winding core 300; the specific structure of the cover assembly 100 refers to the above embodiment. Since the battery 1000 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0049] It should be noted that, in the above embodiment, the sealing member 114 is a sealing rubber ring, which is an elastic member and can rebound. Therefore, the first extension portion 115 must be fixed by other components. Considering the cost and other issues, in this embodiment, please refer to Figure 6. The sealing member 114 and the shell 200 in Figure 6 are both in an unfolded state, and the first extension portion 115 is fixed by the shell 200. Specifically, the end of the shell 200 close to the cover assembly 100 is folded toward the direction of the cover assembly 100 to form a The second extension portion 201 is formed, and the second extension portion 201 is covered on the cover assembly 100, thereby fixing the first extension portion 115 on the top cover 103. The shell 200 is generally made of metal. The metal material undergoes plastic deformation during the bending process and will not return to its original state. Therefore, the first extension portion 115 is pressed and fixed on the top cover 103. At the same time, the cover assembly 100 can also be limited to prevent the cover assembly 100 from being offset, thereby fixing the cover assembly 100 and the core 300 relatively.

[0050] Please refer to Figure 7. The seal 114 and the shell 200 in Figure 7 are both in a folded state. The length of the second extension portion 201 should not be too long or too short. If the length of the second extension portion 201 is too long, the shell 200 will contact the top cover 103 and cause a short circuit. If the length of the second extension portion 201 is too short, the first extension portion 115 cannot be completely suppressed, causing the first extension portion 115 to warp, resulting in multiple welding portions 111 being exposed, and multiple welding portions 111 are at risk of corrosion. Specifically, in this embodiment, the second extension portion has a second end facing the center of the top cover, and the distance from the second end to the center of the top cover is L4, where 17.0mm≤2L4≤17.8mm. More specifically, the L4 can be 17.0mm, 17.05mm, 17.1mm, 17.15mm, 17.2mm, 17.25mm, 17.3mm, 17.35mm, 17.4mm, 17.45mm, 17.5mm, 17.55mm, 17.6mm, 17.65mm, 17.7mm, 17.75mm, or 17.8mm; as a preferred embodiment, the length of the second extension portion 201 is 1.2mm.

[0051] The technical solution of the present application is further described in detail below in conjunction with specific examples and data. It should be understood that the following examples are only used to explain the present application and are not used to limit the present application.

[0052] Example 1

[0053] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0054] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.5 mm and the thickness D2 of the outer layer is 5 μm.

[0055] The material of the connecting piece is aluminum;

[0056] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 40°.

[0057] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0058] Comparative Example 1

[0059] The battery structure provided in Comparative Example 1 is exactly the same as that in Example 1, and all dimensions are also the same. The difference is that the core material and the outer layer of the top cover of Comparative Example 1 are both made of copper.

[0060] Comparative Example 2

[0061] The battery structure provided in Comparative Example 2 is exactly the same as that in Example 1, and all dimensions are also the same. The difference is that the core material of the top cover of Comparative Example 1 is steel, and the material of the outer layer is nickel.

[0062] Example 2

[0063] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0064] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.8 mm and the thickness D2 of the outer layer is 9 μm.

[0065] The material of the connecting piece is aluminum;

[0066] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 40°.

[0067] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0068] Example 3

[0069] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0070] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.4 mm and the thickness D2 of the outer layer is 4 μm.

[0071] The material of the connecting piece is aluminum;

[0072] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 40°.

[0073] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 2.55 mm.

[0074] Example 4

[0075] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0076] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.6 mm and the thickness D2 of the outer layer is 5 μm.

[0077] The material of the connecting piece is aluminum;

[0078] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 30°.

[0079] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0080] Example 5

[0081] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0082] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.6 mm and the thickness D2 of the outer layer is 5 μm.

[0083] The material of the connecting piece is aluminum;

[0084] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 35°.

[0085] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0086] Example 6

[0087] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0088] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.6 mm and the thickness D2 of the outer layer is 5 μm.

[0089] The material of the connecting piece is aluminum;

[0090] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 8.5 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 45°.

[0091] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0092] Example 7

[0093] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0094] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.6 mm and the thickness D2 of the outer layer is 5 μm.

[0095] The material of the connecting piece is aluminum;

[0096] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 7.69 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 40°.

[0097] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0098] Example 8

[0099] The battery includes a cover assembly, a winding core, and a housing. The housing includes a second extension. The distance L4 from the second end of the second extension to the center of the top cover is 17.4 mm. The specific dimensions of the cover assembly are as follows:

[0100] The top cover includes a core material and an outer layer. The core material is made of copper and the outer layer is made of nickel. The thickness D1 of the core material is 0.6 mm and the thickness D2 of the outer layer is 5 μm.

[0101] The material of the connecting piece is aluminum;

[0102] The welding portion includes a first side and a second side. The shortest distance L2 between the first side and the center of the connecting piece is 6.92 mm. The distance L1 between the first side and the second side is 0.25 mm. The arc of the welding portion is 40°.

[0103] The sealing member includes a first extension portion, and a distance L3 from a first end of the first extension portion to the center of the top cover is 14 mm.

[0104] Performance Testing

[0105] 1. Resistance tests were performed on the batteries of Examples 1-8 and Comparative Examples 1-2. The resistance of the cover plate assembly was tested using a resistance meter. The specific test method can refer to conventional test methods in the field. Under the same test conditions, each example was tested multiple times, and the test results of each time were recorded and the average value was calculated. The average value is the actual resistance value of the cover plate assembly. The specific test results are shown in Tables 1 and 2:

[0106] Table 1 Resistance values ​​(mΩ) of Examples 1-3 and Comparative Examples 1-2

[0107] Example 1 Comparative Example 1 Comparative Example 2 Example 2 Example 3 10.1160.1040.2270.1240.09820.1010.1030.2260.1220.09830.0980.0980.2220.1210.09740.1030.1020.2120.1230.10150.1050.1040.1930.1170.09660.1000.1040.2230.1150.09870. 1000.1000.2270.1190.09980.0990.1030.2300.1300.09690.1000.1060.2210.1160.094100.1020.1030.2180.1210.101110.1010.1010.2150.1190.101120.0990.1020.2290.1170.097130.1020.1010.2220.1190. 098140.1060.1010.2340.1120.101150.0990.1070.2140.1160.101160.1080.1030.2310.1150.094170.1030.1000.2240.1200.092180.0960.1010.2320.1210.094190.1020.1030.2140.1130.097200.1010.1020. 2160.1180.099210.0970.1040.2200.1150.096220.1000.1030.2140.1150.095230.0980.1010.2160.1200.099240.1000.1020.2110.1280.095250.1040.1010.2240.1200.098Average 0.10160.102360.22060.1190.097

[0108] Table 2 Resistance values ​​of Examples 4-8 (mΩ)

[0109] Example 4 Example 5 Example 6 Example 7 Example 8 10.124 0.103 0.1000.101 0.1042 0.122 0.108 0.101 0.102 0.1023 0.121 0.109 0.101 0.102 0.1034 0.123 0.108 0.1000.096 0.1065 0.117 0.107 0.1010.098 0.1056 0.115 0.107 0.1000.099 0.1047 0.1 190.1100.0960.1010.10380.1300.1070.0970.1060.10490.1160.1100.0980.1030.105100.1210.1070.1000.1040.101110.1190.1110.1010.1010.106120.1170.1100.0980.1030.100130.1190.1080.0960.1120.10 1140.1120.1100.1000.1080.105150.1160.1100.0990.1060.099160.1150.1120.1030.1000.100170.1200.1120.1050.1040.099180.1210.1110.1020.1030.107190.1130.1130.1010.0980.106200.1180.1140.1060 .1100.098210.1150.1050.1040.1120.104220.1150.1100.1090.1070.103230.1200.1110.1020.0990.105240.1280.1040.1030.1010.101250.1200.1040.1070.1060.106Average 0.119040.108840.10120.103280.10308

[0110] It can be concluded from Example 1 and Comparative Example 1 that under the same conditions, the resistance value tested in Example 1 is 0.1016 mΩ, and the resistance value tested in Comparative Example 1 is 0.10236 mΩ. According to the data, it can be seen that the resistance values ​​of Example 1 and Comparative Example 1 are not much different, but the resistance value of Example 1 is slightly smaller than that of Comparative Example 1. Therefore, the use of copper nickel plating can reduce the resistance value of the top cover.

[0111] It can be concluded from Example 1 and Comparative Example 2 that: under the same conditions, the resistance value of Example 1 tested is 0.1016mΩ, and the resistance value of Comparative Example 2 tested is 0.2206mΩ. According to the data, it can be concluded that the resistance value of Example 1 is half of the resistance value of Comparative Example 2. Compared with steel material, the copper nickel plating method used in this application can effectively reduce the resistance value of the top cover.

[0112] It can be concluded from Example 1, Example 2 and Example 3 that: under the same conditions, the core material thickness and outer layer thickness of Example 2 are both greater than those of Example 1, the resistance value of Example 1 is 0.1016mΩ, the resistance value of Example 2 is 0.10328mΩ, and the resistance value of Example 2 is greater than that of Example 1. The core material thickness and outer layer thickness of Example 3 are both less than those of Example 1, and the resistance value of Example 3 is 0.097mΩ, which is slightly less than that of Example 1, that is, the relationship between the resistance values ​​of Example 1, Example 2 and Example 3 is: Example 3 < Example 1 < Example 2. According to the above relationship, it can be seen that as the thickness of the core material and the thickness of the outer layer increase, the resistance value of the top cover increases accordingly. However, when considering the resistance value, the strength of the top cover also needs to be considered. If the core material thickness and the outer layer thickness are infinitely reduced, the strength of the top cover itself will also be reduced.

[0113] From Example 1, Example 4, Example 5 and Example 6, it can be concluded that: under the same conditions, the curvature of the welding portion of Example 4 is smaller than the curvature of the welding portion of Example 5, the curvature of the welding portion of Example 5 is smaller than the curvature of the welding portion of Example 1, the curvature of the welding portion of Example 1 is smaller than the curvature of the welding portion of Example 6, the resistance value of Example 4 is greater than the resistance value of Example 5, the resistance value of Example 5 is greater than the resistance value of Example 1, the resistance value of Example 1 is smaller than the resistance value of Example 6, and the resistance value of Example 6 is smaller than the resistance value of Example 5. The relationship between the resistance values ​​of Example 1, Example 4, Example 5 and Example 6 is: Example 1 < Example 6 < Example 5 < Example 4, and the resistance value of the top cover increases with the increase of the welding portion. The resistance of the top cover will increase with the increase of the curvature of the welding part. When the curvature of the welding part increases to a certain value, the resistance of the top cover will increase again as the curvature of the welding part increases. The function of the welding part is to perform welding. The difficulty of welding will affect the thickness of the outer layer. During the welding process, the simpler the welding degree, the smaller the impact on the thickness of the outer layer. The more complex the welding degree, the greater the impact on the outer layer. The greater the impact on the outer layer, the greater the degree of change in the relationship between the outer layer and the core material, and therefore the greater the impact on the resistance value of the top cover. Therefore, it can be seen from Examples 1, 4, 5 and 6 that, under the same conditions, the curvature of the welding part can have a certain impact on the resistance value of the top cover, reflecting that the curvature of the welding part has a certain impact on the welding of the top cover.

[0114] It can be concluded from Example 1, Example 7 and Example 8 that: under the same conditions, the positions of the welding parts of Example 1, Example 7 and Example 8 are different. The welding part of Example 8 is farthest from the center of the connecting piece, and the welding part of Example 6 is closest to the center of the connecting piece. The resistance value of Example 8 is smaller than the resistance value of Example 6, which is smaller than the resistance value of Example 7. According to the relationship between the three, it can be seen that the position of the welding part can affect the difficulty of welding. The simpler the welding, the smaller the impact on the thickness of the outer layer. The more complex the welding, the greater the impact on the outer layer. As the distance between the welding part and the connecting piece changes, As the welding part gets closer to the center of the connecting piece, the resistance of the top cover increases, indicating that the welding difficulty increases. As the distance increases, the resistance value of the top cover begins to decrease again. However, the closer the welding part is to the center of the connecting piece, the larger the size of the first extension part needs to be (the first extension part needs to cover the welding part to prevent the welding part from being corroded). When the size of the first extension part increases, the size of the second extension part also increases (the second extension part presses against the first extension part to prevent the first extension part from warping). The increase in the size of the second extension part will cause the negative and positive poles of the battery to get closer and closer, posing a risk of short circuit. Therefore, the welding part should not be too close to the center of the connecting piece.

[0115] 2. The top covers of Examples 1-8 were subjected to a salt spray test. The top covers of Examples 1-8 were placed in a neutral salt spray test chamber for testing. The surface conditions of the top covers were observed at intervals. The specific test results are shown in Table 3:

[0116] Table 3 Salt spray test results

[0117] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 12h No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina 24h No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina 36h No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina 48h No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina No patina

[0118] It can be concluded from Table 3 that the top covers provided in Examples 1-8 all showed patina during the salt spray test, indicating good corrosion resistance.

Claims

1. A cover plate assembly (100), comprising: A connecting assembly (101) comprises a connecting sheet (102), wherein the connecting sheet (102) is made of aluminum; and A top cover (103) is disposed on the connecting sheet (102), the top cover (103) comprising a core material (104) and an outer layer (105) located outside the core material (104), the core material (104) is welded to the connecting sheet (102) via the outer layer (105), the material of the core material (104) comprises copper, and the material of the outer layer (105) comprises nickel.

2. The cover plate assembly (100) according to claim 1, wherein: The thickness of the core material (104) is D1, wherein D1≥0.1 mm, and the thickness of the outer layer (105) is D2, wherein D2≥3 μm.

3. The cover plate assembly (100) according to claim 2, wherein: 0.4mm≤D1≤0.8mm, 4μm≤D2≤9μm.

4. The cover plate assembly (100) according to claim 1, wherein: The connection assembly (101) further comprises a perforated plate (106), wherein the perforated plate (106) is connected to a side of the connection sheet (102) facing away from the top cover (103); The connecting piece (102) comprises a first connecting portion (107) and a second connecting portion (108) connected to the periphery of the first connecting portion (107), the second connecting portion (108) being connected to the top cover (103), the first connecting portion (107) being connected to the orifice plate (106), and the first connecting portion (107) being recessed in a direction away from the top cover (103) to form a first gap (109) between the first connecting portion (107) and the top cover (103).

5. The cover plate assembly (100) according to claim 4, wherein: The second connecting portion (108) is formed with a first notch (110), the opening of the first notch (110) is arranged toward the top cover (103), and the width of the first notch (110) is gradually reduced in a direction from the second connecting portion (108) toward the orifice plate (106); and / or, A second notch (119) is formed on the orifice plate (106), the opening of the second notch (119) is arranged toward the first connecting portion (107), and the width of the second notch (119) is reduced in a direction from the first connecting portion (107) toward the orifice plate (106).

6. The cover plate assembly (100) according to claim 4, wherein: A second gap (118) is formed between the second connecting portion (108) and the orifice plate (106), and an insulating member (120) is provided in the second gap (118).

7. The cover plate assembly (100) according to any one of claims 1 to 6, wherein: A plurality of welding portions (111) are formed on an end surface of the top cover (103) facing away from the connecting piece (102), and the plurality of welding portions (111) surround the center of the connecting piece (102).

8. The cover plate assembly (100) according to claim 7, wherein: Each welding portion (111) has a first side edge (112) and a second side edge (113) which are arranged opposite to each other, the second side edge (113) being arranged close to an edge of the connecting piece (102), the distance between the first side edge (112) and the second side edge (113) being L1, and the shortest distance between the first side edge (112) and the center of the connecting piece (102) being L2, wherein 0.1 mm ≤ L1 ≤ 0.3 mm, and 6.8 mm ≤ L2 < 8.7 mm.

9. The cover plate assembly (100) according to claim 7, wherein: The arc angle of each welding portion (111) is α, wherein 35°≤α≤45°.

10. The cover plate assembly (100) according to claim 7, further comprising a sealing member (114), wherein the sealing member (114) surrounds the outer sides of the top cover (103) and the connecting assembly (101).

11. The cover plate assembly (100) according to claim 10, wherein: One end of the sealing member (114) close to the top cover (103) is folded in a direction toward the top cover (103) to form a first extension portion (115); the first extension portion (115) is covered on the plurality of welding portions (111); and an orthographic projection of the first extension portion (115) on the top cover (103) covers the plurality of welding portions (111).

12. The cover plate assembly (100) according to claim 11, wherein: The first extension portion (115) has a first end facing the center of the top cover (103), and the distance from the first end to the center of the top cover (103) is L3, wherein 13.6 mm≤2L3≤14.4 mm.

13. A battery (1000), comprising: A housing (200), wherein a cavity is formed in the housing (200); A winding core (300) is disposed in the housing (200); and The cover plate assembly (100) according to any one of claims 1 to 12, wherein the cover plate assembly (100) is covered on the winding core (300), and the connecting assembly (101) is connected to the winding core (300).

14. The battery (1000) according to claim 13, wherein: One end of the shell (200) close to the cover assembly (100) is folded in the direction of the cover assembly (100) to form a second extension portion (201), and the second extension portion (201) is covered on the cover assembly (100) to relatively fix the cover assembly (100) and the winding core (300).

15. The battery (1000) according to claim 14, wherein: The second extension portion (201) has a second end facing the center of the top cover (103), and the distance from the second end to the center of the top cover (103) is L4, wherein 17.0 mm≤2L4≤17.8 mm.

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