Cover plate assembly, battery cell, and battery pack

Abstract

To provide a cover plate assembly, a battery cell, and a battery pack that can further improve the stability and reliability of connection between external conductive members in the cover plate assembly.SOLUTION: A cover plate assembly includes a cover plate body, external conductive members, and an electrode lead-out member. The cover plate body is provided with a through hole. The external conductive member is disposed on a side of the cover plate body away from an electrode assembly and includes a first metal layer 21, a second metal layer 22, and a third metal layer 23 disposed between the first metal layer and the second metal layer. The electrode lead-out member passes through the through hole and is electrically connected to the external conductive member. The third metal layer is respectively connected to the first metal layer and the second metal layer to form a first composite layer and a second composite layer. The first composite layer includes a first metal and a third metal. The second composite layer includes a second metal and the third metal.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to the technical field of battery cells, and more particularly to a cover plate assembly, a battery cell, and a battery pack.

Background Art

[0002] The inventor knows a method of externally electrically connecting a battery cell to an external electrical connection member through an external conductive member within the battery cell. The external conductor member is generally composed of a copper plate and an aluminum plate. The copper plate and the aluminum plate are fixed by riveting.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In the prior art, there is a problem that a gap easily occurs in the connection portion between the copper plate and the aluminum plate, resulting in a decrease in connection reliability.

[0004] In view of the above drawbacks of the prior art, an object of the present invention is to provide a cover plate assembly and a battery cell for solving the problem that a gap easily occurs in the connection portion between the copper plate and the aluminum plate and the connection reliability decreases because the copper plate and the aluminum plate of the external conductor portion of the battery cell are fixed by riveting.

Means for Solving the Problems

[0005] To achieve the above object and other related objects, the present invention provides a cover plate assembly including a cover plate body, an external conductive member, and an electrode lead-out member. A through-hole is disposed in the cover plate body. The external conductive member is disposed on a side of the cover plate body away from the electrode assembly. The external conductive member includes a first metal layer, a second metal layer, and a third metal layer disposed between the first metal layer and the second metal layer. The first metal layer contains a first metal, the second metal layer contains a second metal, and the third metal layer contains a third metal. The third metal layer is connected to the first metal layer and the second metal layer respectively to form a first composite layer and a second composite layer. The first composite layer contains the first metal and the third metal. The second composite layer contains the second metal and the third metal. The electrode lead-out member passes through the through-hole and is electrically connected to the external conductive member.

[0006] In one embodiment of the present invention, the content of the first metal in the first composite layer increases in a direction from a position away from the first metal layer toward a position closer to the first metal layer.

[0007] Alternatively, the content of the second metal in the second composite layer increases in a direction from a position away from the second metal layer toward a position closer to the second metal layer.

[0008] In one embodiment of the present invention, the content of the second metal in the second composite layer is more than the content of the first metal in the first composite layer.

[0009] In one embodiment of the present invention, the third metal layer covers at least a part of the surface of the first metal layer close to the second metal layer, or a part of the surface of the second metal layer close to the first metal layer.

[0010] In one embodiment of the present invention, the third metal layer completely covers the larger one of the surface of the first metal layer close to the second metal layer and the surface of the second metal layer close to the first metal layer.

[0011] In one embodiment of the present invention, the third metal layer uniformly covers the surface of the first metal layer close to the second metal layer or the surface of the second metal layer close to the first metal layer.

[0012] In one embodiment of the present invention, at least one protrusion is disposed on the surface of one of the first metal layer and the second metal layer close to the other of the first metal layer and the second metal layer. On the surface of the other of the first metal layer and the second metal layer close to one of the first metal layer and the second metal layer, a first fitting hole corresponding to at least one protrusion is disposed. In the third metal layer, a second fitting hole corresponding to at least one protrusion is disposed, and at least one protrusion is fitted and connected to the corresponding first fitting hole and second fitting hole.

[0013] In one embodiment of the present invention, at least one protrusion is disposed on the surface of the first metal layer close to the second metal layer. On the surface of the second metal layer close to the first metal layer, a first fitting hole that fits at least one protrusion is disposed. In the third metal layer, a second fitting hole that fits at least one protrusion is disposed, and at least one protrusion is fitted and connected to the corresponding first fitting hole and second fitting hole.

[0014] In one embodiment of the present invention, at least one protrusion is symmetrically distributed on one of the first metal layer and the second metal layer along the central axis of the external conductive member. The first fitting holes are symmetrically distributed on the other of the first metal layer and the second metal layer along the central axis of the external conductive member. The second fitting holes are symmetrically distributed on the third metal layer along the central axis of the external conductive member.

[0015] In one embodiment of the present invention, the outer surface of at least one protrusion or the inner surface of the first fitting hole is covered by the third metal layer.

[0016] In one embodiment of the present invention, along the radial direction of the outer conductive member, in the direction from away from the through hole towards the through hole, among the surfaces of the second metal layer close to the first metal layer, the portion exceeding the first metal layer is not covered by the third metal layer.

[0017] In one embodiment of the present invention, the thickness of the third metal layer is set to be 0.5 μm to 1000 μm.

[0018] In one embodiment of the present invention, the thickness of the third metal layer is set to be 5 μm to 10 μm.

[0019] In one embodiment of the present invention, the thickness of the second composite layer is d, the total thickness of the first composite layer and the second composite layer is a, and the relational expression 0.2a ≤ d ≤ 0.9a is satisfied.

[0020] In one embodiment of the present invention, the third metal layer contains at least one of nickel, silver, and tin.

[0021] The present invention also provides a battery cell including a cover plate assembly according to any one of the above embodiments.

[0022] The present invention also provides a shell in which an electrode assembly is installed.

[0023] One end of the electrode lead-out member in the cover plate assembly is connected to the electrode assembly, the other end passes through the through-hole, and is electrically connected to the second metal layer of the cover plate assembly.

[0024] The present invention also provides a battery pack including a battery cell.

Advantages of the Invention

[0025] The present invention provides a cover plate assembly, a battery cell, and a battery pack. By disposing a third metal layer between a first metal layer and a second metal layer, the third metal layer forms a first composite layer including a first metal and the third metal together with the first metal layer, and forms a second composite layer including a second metal and the third metal together with the second metal layer. That is, a metal composite layer is formed at the contact positions of the third metal layer with the first metal layer and the second metal layer, ensuring the connection reliability and stability between the first metal layer and the second metal layer. The third metal layer can fill the gap between the first metal layer and the second metal layer, and can further improve the connection reliability and stability between the first metal layer and the second metal layer.

Brief Description of the Drawings

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings necessary for the description of the embodiments are briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. Those skilled in the art can also obtain other drawings according to these drawings without creative efforts.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0027] Hereinafter, the implementation of the present invention will be described through specific examples. A person skilled in the art can easily understand other advantages and effects of the present invention from the disclosure of this specification. The present invention can also be implemented or applied through other different specific implementations. Without departing from the spirit of the present invention, various modifications or changes can be made to the details of the specification based on different viewpoints and applications.

[0028] It should be noted that the drawings provided in the embodiments only schematically show the basic concepts of the present invention, and the drawings only show the assemblies related to the present invention, and the number, shape, and dimensions of the assemblies are not drawn according to the actual implementation. In the actual implementation, the type, number, and ratio of each assembly can be freely changed, and the type of the layout of the assemblies may also become more complex.

[0029] Please refer to FIGS. 1-8. The present invention provides a cover plate assembly, a battery cell, and a battery pack. The inventor knows a method of connecting a battery cell to an external electrical connection member via an external conductive member within the battery cell. The external conductive member generally consists of a composite plate of copper and aluminum, or is formed by frictionally welding a copper layer and an aluminum layer. However, the solution of adopting a composite plate has problems such as high raw material costs, complex processes, and low material utilization rate during manufacturing. The adoption of friction welding has problems such as complex processes, large processing amounts, low material usage rate, and very high costs. There are also components composed of a copper plate and an aluminum plate. The copper plate and the aluminum plate are fixedly connected by riveting to form an external conductor member. In this method, gaps are likely to occur at the connection part between the copper plate and the aluminum plate, and the connection may become unstable. Please refer to FIG. 1. In order to prevent the problem of gaps at the connection part between the copper plate and the aluminum plate by riveting, in the prior art, brazing was performed between the copper plate and the aluminum plate. However, in the actual manufacturing process, if too much solder is applied in the center, the solder is likely to overflow from the side surfaces of the first metal layer 21 and the second metal layer 22, and / or from the gap between the protruding portion 201 and the first fitting hole 202, which will affect other processes. If the application amount is too small, gaps still exist between the adjacent surfaces of copper and aluminum, and / or between the protruding portion 201 and the first fitting hole 202, so that the contact area becomes excessively small and it is difficult to ensure strength. Also, due to the uniformity of the solder, there is a problem that the riveted column on the aluminum slightly protrudes and the height consistency decreases. For example, when the solder on the adjacent surfaces of the first metal layer 21 and the second metal layer 22 is unevenly distributed, the height of the surface of the external conductive member with respect to the cover plate body 10 becomes uneven. Therefore, in order to solve the above problems, the present invention provides a cover plate assembly and a battery cell. The cover plate assembly 100 includes a cover plate body 10, an external conductive member 20, and an electrode lead-out member.The cover plate body 10 is provided with a through hole, the external conductive member 20 is disposed on the side away from the electrode assembly of the cover plate body 10, and the electrode lead-out member passes through the through hole and is connected to the external conductive member 20.

[0030] Refer to FIGS. 2 to 8. In the present embodiment, the external conductive member 20 includes a first metal layer 21, a second metal layer 22, and a third metal layer 23. The first metal layer 21 contains a first metal, the second metal layer 22 contains a second metal, and the third metal layer 23 contains a third metal. The third metal layer 23 is disposed between the first metal layer 21 and the second metal layer 22, and the third metal layer 23 is connected to the first metal layer 21 and the second metal layer 22 respectively to form a first composite layer and a second composite layer. Here, the first composite layer contains the first metal and the third metal, and the second composite layer contains the second metal and the third metal. That is, in the present invention, since the third metal layer 23 is disposed between the first metal layer 21 and the second metal layer 22, a composite layer is formed at the joint between the third metal layer 23 and the first metal layer 21, so that the first metal layer 21 and the second metal layer 22 are stably connected, the joint area becomes large, and the connection reliability and stability between the first metal layer 21 and the second metal layer 22 are ensured. In addition, the third metal layer 23 is disposed between the first metal layer 21 and the second metal layer 22 to prevent the problem of the height mismatch of the surface of the external conductive member with respect to the cover plate body 10 caused by the uneven filling of the solder between the first metal layer 21 and the second metal layer 22. Further, the first metal layer 21, the second metal layer 22, and the third metal layer 23 are joined by hot pressing. During hot pressing, a uniform stress is applied to the surfaces of the first metal layer 21 and the second metal layer 22, Thereby, higher consistency of the external conductive member 20 is further ensured.

[0031] In addition, the external conductive member 20 is preferably a negative conductive member of the battery cell.

[0032] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the third metal layer 23 is fixedly connected to the first metal layer 21 and the second metal layer 22 by hot pressing to form the first composite layer and the second composite layer. By hot pressing, a stable connection between the first metal layer 21 and the second metal layer 22 becomes possible, the bonding area becomes larger, and by hot pressing, the contact position between the first metal layer 21 and the third metal layer 23 is partially fused to form a metal composite part, thereby forming a composite layer. The contact position between the second metal layer 22 and the third metal layer 23 is partially melted to form a part of the metal composite part. Thereby, the hot pressing effect is improved, and the third metal layer 23 can fill the gap between the first metal layer 21 and the second metal layer 22, thereby ensuring the connection reliability and stability between the first metal layer 21 and the second metal layer 22.

[0033] Note that there are at least three main elements in the joint between the first metal layer 21 and the second metal layer 22, which are respectively the main element of the first metal layer 21, the main element of the second metal layer 22, and the main element of the third metal layer 23. The main element refers to the element with the highest content among the three different metal layers. In this embodiment, the first metal layer 21 is an aluminum layer, the second metal layer 22 is a copper layer, and the third metal layer 23 is at least one of nickel, silver, and tin, preferably nickel, whereby the third metal layer 23 can prevent oxidation and corrosion of the first metal layer 21 and the second metal layer 22.

[0034] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the content of the first metal in the first composite layer increases along the direction from a position away from the first metal layer 21 to a position closer to the first metal layer 21, that is, the content of the first metal increases along the direction from the second metal layer 22 to the first metal layer 21, enabling a good transition between the first metal layer 21 and the third metal layer 23 and ensuring the connection reliability between the first metal layer 21 and the third metal layer 23. And / or the content of the second metal in the second composite layer increases along the direction from a position away from the second metal layer 22 to a position closer to the second metal layer 22, that is, the content of the second metal increases along the direction from the first metal layer 21 to the second metal layer 22, enabling a good transition between the second metal layer 22 and the third metal layer 23 and ensuring the connection reliability between the second metal layer 22 and the third metal layer 23, thereby ensuring the stability of the overall structure of the external conductive member 20. Further, by having the content of the second metal in the second composite layer be more than the content of the first metal in the first composite layer, excellent conductive characteristics of the external conductive member can also be ensured while ensuring a strong connection between the layers.

[0035] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the external conductive member 20 may be manufactured by first processing the first metal layer 21 and the second metal layer 22 into a single component, and then fixing the first metal layer 21, the second metal layer 22, and the third metal layer 23 by hot pressing. Alternatively, the first metal layer 21, the second metal layer 22, and the third metal layer 23 may be fixedly connected by hot pressing and then processed to form the external conductive member 20. That is, after the first metal layer 21, the second metal layer 22, and the third metal layer 23 are separately processed and formed, they may be connected to form the external conductive member 20, or after the first metal layer 21, the second metal layer 23, and the third metal layer 23 are connected and formed, they may be processed next to form the external conductive member 20. Thereby, the manufacturing difficulty is reduced, and since each member can be individually processed and formed, there is no waste of materials, the material utilization rate is improved, and the material cost is reduced. In this embodiment, in the connection process between the first metal layer 21, the second metal layer 22, and the third metal layer 23, the third metal layer 23 may be fixedly connected to either the first metal layer 21 or the second metal layer 22 first, and then fixedly connected to the other one.

[0036] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the third metal layer 23 covers at least a part of the surface of the first metal layer 21 close to the second metal layer 22, or a part of the surface of the second metal layer 22 close to the first metal layer 21. That is, since a part of the adjacent surface region of the first metal layer 21 or the second metal layer 22 is covered by the third metal layer 22, a region covered by the third metal layer 23 forms a composite layer after hot pressing, and the connection reliability between the first metal layer 21 and the second metal layer 22 after hot press fixing is ensured. Further, since the third metal layer 23 completely covers the larger area of the surface of the first metal layer 21 close to the second metal layer 22 and the surface of the second metal layer 22 close to the first metal layer 21, after hot pressing, the third metal layer 23 can completely fill the gap between the two opposing surfaces of the first metal layer 21 and the second metal layer 22, and the connection area between the first metal layer 21 and the second metal layer 22 can be made sufficiently large. Thereby, the conductivity of the external conductive member 20 can be ensured, and the connection reliability between the first metal layer 21 and the second metal layer 22 can be improved.

[0037] Please refer to FIGS. 2 and 4 to 8. In the present embodiment, the third metal layer 23 uniformly covers the surface of the first metal layer 21 close to the second metal layer 22, or the surface of the second metal layer 22 close to the first metal layer 21. By uniformly covering the surface of the first metal layer 21 or the second metal layer 22 with the third metal layer 23, it is possible to prevent the influence on the hot press effect due to the non-uniform thickness of the third metal layer 23. Thereby, while improving the connection reliability between the first metal layer 21 and the second metal layer 22, the problem of non-uniform height of the external conductive member 20 caused by the non-uniform thickness of the third metal layer 23 on the surface of the first metal layer 21 or the surface of the second metal layer 22 is avoided, and the consistency of the height of the external conductive member 20 is improved. Thereby, the connection between the external conductive member 20 and other structures becomes easy. For example, in the present embodiment, the third metal layer 23 uniformly covers the surface of the first metal layer 21 by electroplating to form an integral structure with the first metal layer 21, or uniformly covers the surface of the second metal layer 22 to form an integral structure with the second metal layer 22. Of course, in some other embodiments, the third metal layer 23 may uniformly cover the first metal layer 21 or the second metal layer 22 by spraying.

[0038] Please refer to FIGS. 2 and 4 to 8. In this embodiment, on the surface of the first metal layer 21 and the second metal layer 22 closer to the other, at least one protrusion 201 is disposed, and on the other surface closer to one, a first fitting hole 202 corresponding to the at least one protrusion 201 is disposed. In the third metal layer 23, a second fitting hole 203 corresponding to the protrusion 201 is disposed. The at least one protrusion 201 is fitted and connected to the corresponding first fitting hole 202 and second fitting hole 203. For example, on the surface of the first metal layer 21 closer to the second metal layer 22, the protrusions 201 are disposed, and the protrusions 201 are arranged at equal intervals along the circumferential direction on the first metal layer 21. Correspondingly, in the second metal layer 22, a plurality of first fitting holes 202 that fit the protrusions 201 are disposed, and in the third metal layer 23, a second fitting hole 203 that fits the protrusions 201 is disposed. The protrusions 201 are fitted and connected to the corresponding first fitting holes 202 and second fitting holes 203, thereby further improving the connection reliability and stability between the first metal layer 21 and the second metal layer 22 by riveting the protrusions and the fitting holes. During the hot press process, the third metal layer 23 is connected to the first metal layer 21 and the second metal layer 22 respectively to form a first composite layer and a second composite layer. At the same time, the protrusions 201 can be synchronously press-fitted into the first fitting holes 202 and the second fitting holes 203 to achieve a highly reliable connection between the first metal layer 21 and the second metal layer 22. That is, since the two processes of hot press connection and riveting are realized in one process, the manufacturing difficulty is reduced, the production capacity is improved, and the cost is reduced.

[0039] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the protrusions 201 are symmetrically distributed on one of the first metal layer 21 and the second metal layer 22 along the central axis L of the external conductive member 20, the first fitting holes 202 are symmetrically distributed on the other of the first metal layer 21 and the second metal layer 22 along the central axis L of the external conductive member 20, and the second fitting holes 203 are symmetrically distributed on the third metal layer 23 along the central axis L of the external conductive member 20. That is, since the protrusions 201, the first fitting holes 202, and the second fitting holes 203 are symmetrically distributed along the central axis L of the external conductive member 20, when fitting and connecting the first metal layer 21, the second metal layer 22, and the third metal layer 23, the protrusions 201, the first fitting holes 202, and the second fitting holes 203 are fitted and connected, facilitating riveting. At the same time, due to the symmetrical distribution along the central axis L, uniform stress can be applied to each position when connecting the first metal layer 21, the second metal layer 22, and the third metal layer 23, thereby improving the stability and reliability of the connection between the metal layers.

[0040] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the outer surface of the protrusions 201 or the inner surface of the first fitting holes 202 is covered by the third metal layer 23. That is, the third metal layer 23 covers the two opposing surfaces of the first metal layer 21 and the second metal layer 22, as well as the space between the protrusions 201 and the first fitting holes 202. Therefore, after hot pressing and riveting, the third metal layer 23 can fill the gap between the protrusions 201 and the first fitting holes 202, improving the riveting effect and further ensuring the reliability of the connection between the first metal layer 21 and the second metal layer 22.

[0041] Refer to FIGS. 2 and 4. In the present embodiment, along the radial direction of the external conductive member 20, in the direction from the direction away from the through hole toward the through hole, among the surfaces of the second metal layer 22 close to the first metal layer 21, the portion exceeding the first metal layer 21 is not covered by the third metal layer 23, and the portion not covered by the third metal layer 23 is connected to the electrode lead-out member by, for example, welding. Since this portion is not covered by the third metal layer 23, the electrode lead-out member is directly welded to the second metal layer 22, thereby ensuring the stability and reliability of the welding between the electrode lead-out member and the second metal layer 22.

[0042] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the thickness of the third metal layer 23 is set to be 0.5 μm to 1000 μm. In reality, if the thickness is less than 0.5 μm, during hot pressing, the third metal layer 23 cannot completely fill the gap between the first metal layer 21 and the second metal layer 22, which easily affects the connection reliability between the first metal layer 21 and the second metal layer 22. If the thickness exceeds 1000 μm, during hot pressing, it easily affects the hot pressing effect among the first metal layer 21, the second metal layer 22, and the third metal layer, which affects the connection reliability between the first metal layer 21 and the second metal layer 22. Also, a thicker metal portion will exist between the first metal layer 21 and the second metal layer 22 after hot pressing, which may easily affect the overall conductive characteristics of the external conductive member 20. Therefore, the thickness of the third metal layer 23 is set to be 0.5 μm to 1000 μm. Thereby, the third metal layer 23 can completely fill the gap between the first metal layer 21 and the second metal layer 22, and the hot pressing effect during hot pressing can also be ensured. Thereby, the connection reliability between the first metal layer 21 and the second metal layer 22 can be ensured, and a composite layer with a thickness sufficient to ensure the conductive performance of the entire external conductive member 20 can be smoothly formed. Further, the thickness of the third metal layer 23 is set to be 5 μm to 10 μm. If the thickness is less than 5 μm, a composite layer with a sufficient thickness cannot be formed during hot pressing, which easily affects the connection reliability between the first metal layer 21 and the second metal layer 22. If the thickness exceeds 10 μm, it easily affects the thickness of the entire external conductive member 20, and thereby, the surface of the external conductive member 20 will protrude excessively high with respect to the cover plate body 10. This affects the subsequent connection between the external conductive member 20 and other structures and the assembly of the battery cell. Therefore, in order to form a composite layer with a sufficient thickness, the thickness of the third metal layer 23 is set to be 5 μm to 10 μm. Thereby, the connection between the first metal layer 21 and the second metal layer 22 is ensured, and the height of the external conductive member 20 can be prevented from becoming excessively high. Thereby, the subsequent connection between the external conductive member 20 and other structures and the assembly of the battery cell can be smoothly carried out.In addition, in the present embodiment, the thickness of the second composite layer is d, the total thickness of the first composite layer and the second composite layer is a, and the thickness of the second composite layer and the total thickness satisfy the relational expression 0.2a ≦ d ≦ 0.9a. As a result, a composite layer with a sufficient thickness is formed, and the third metal layer 22 is surely connected between the first metal layer 21 and the second metal layer 22 after hot pressing.

[0043] Please refer to FIGS. 2 and 4 to 8. In this embodiment, the external conductive member 20 can be obtained, for example, through the following steps. First, the first metal layer 21 and the second metal layer 22 are each processed into a required shape. If necessary, the third metal layer 23 is plated on the surface of the first metal layer 21 close to the second metal layer 22 or the surface of the second metal layer 22 close to the first metal layer 21 to facilitate the bonding between the two. The first metal layer 21 and the second metal layer 22 are fitted together. The fitted first metal layer 21 and second metal layer 22 are placed on a hot press machine and hot pressed. After raising the press block to a predetermined temperature, the press block is lowered, whereby the press block contacts and extrudes the surfaces of the first metal layer 21 and the second metal layer 22. During the hot press process, the third metal layer 23 forms a composite layer with the first metal layer 21 and the second metal layer 22 respectively, and the protrusion 201 is simultaneously riveted to the first fitting hole 202, so that the processing of the external conductive member 20 can be completed. Since the two steps of hot press connection and riveting can be realized in one step, the manufacturing difficulty is reduced, and the production capacity can be improved and the cost can be reduced. Note that the press block in contact with the first metal layer 21 and the second metal layer 22 may be made of a material with high hardness or high thermal conductivity such as graphite. In order to bond the third metal layer 23 to the first metal layer 21 and the second metal layer 22 to form a composite layer, the temperatures of the press blocks corresponding to the first metal layer 21 and the second metal layer 22 must be below their melting points respectively. Note that after peeling the first metal layer 21 and the second metal layer 22 in the external conductive member 20, the remaining area of the third metal layer 23 electroplated on one of the first metal layer 21 and the second metal layer 22 remaining on the other of the first metal layer 21 and the second metal layer is S1, the area of the third metal layer 23 is S2, and the area S1 and the area S2 satisfy the relational expression 0.3S2 ≤ S1 ≤ S2. Further, the remaining area S1 and the third metal layer area S2 of the third metal layer satisfy the relational expression 0.6S2 ≤ S1 ≤ 0.9S2. For example, before hot pressing, the third metal layer 23 is electroplated on the surface of the second metal layer 22. After peeling, a part of the third metal layer 23 is adhered onto the first metal layer 21.That is, the remaining area S1 of the third metal layer 23 on the first metal layer 21 after peeling is set between 0.3S2 and S2, and it is ensured that the third metal layer 23, the first metal layer 22, and the second metal layer 23 are firmly fused and connected during hot pressing, thereby improving the connection reliability and stability between the first metal layer 21 and the second metal layer 22.

[0044] Please refer to FIGS. 2 to 8. The present invention also provides a battery cell including a cover plate assembly 100 and a shell. The electrode assembly is installed within the shell. One end of the electrode lead-out member in the cover plate assembly 100 is connected to the electrode assembly, and the other end passes through the through-hole and is electrically connected to the second metal layer 22 of the cover plate assembly 100. A through-hole is arranged in the cover plate body 10 and surrounded by a groove 102 and an outer support member 103. The outer support member 103 is arranged on the outer periphery of the outer conductive member 20 and installed within the groove 102. The cover plate assembly 100 is the same as or similar to the structure of the cover plate assembly 100 described in the above embodiment. To avoid repetition, the description is omitted here.

[0045] The present invention provides a cover plate assembly, a battery cell, and a battery pack. By disposing a third metal layer between the first metal layer and the second metal layer, the third metal layer forms a first composite layer including the first metal and the third metal together with the first metal layer, and forms a second composite layer including the second metal and the third metal together with the second metal layer. That is, a metal composite layer is formed at the contact positions of the third metal layer with the first metal layer and the second metal layer, ensuring the connection reliability and stability between the first metal layer and the second metal layer. The third metal layer can fill the gap between the first metal layer and the second metal layer, and can further improve the connection reliability and stability between the first metal layer and the second metal layer.

[0046] The above description is only an explanation of the preferred embodiments of the present invention and the technical principles used. Those skilled in the art should understand that the scope covered by the present invention is not limited to the technical solutions formed by specific combinations of the above technical features. For example, without departing from the concept of the present invention, other technical solutions formed by arbitrarily combining the above technical features or their equivalent features, such as replacing the above features with technical features having the same functions as those disclosed (but not limited to) in the present invention, are also included.

[0047] Except for the technical features described in this specification, the remaining technical features are known to those skilled in the art. To emphasize the inventive features of the present invention, the remaining technical features will not be described in detail here.

Industrial Applicability

[0048] The cover plate assembly, battery cell, and battery pack of the present invention can be applied in the field of battery cells.

Explanation of Reference Numerals

[0049] 100: Cover plate assembly 10: Cover plate body 20: External conductive member 102: Groove 103: Outer support member 21: First metal layer 22: Second metal layer 23: Third metal layer 201: Protrusion 202: First fitting hole 203: Second fitting hole

Claims

1. A cover plate body in which a through hole is disposed, An external conductive member disposed on a side of the cover plate body away from the electrode assembly, including a first metal layer, a second metal layer, and a third metal layer disposed between the first metal layer and the second metal layer, Comprising, The first metal layer contains a first metal, The second metal layer contains a second metal, The third metal layer contains a third metal, The third metal layer is connected to the first metal layer and the second metal layer respectively to form a first composite layer and a second composite layer, The first composite layer contains the first metal and the third metal, and the second composite layer contains the second metal and the third metal, An electrode lead-out member passes through the through hole and is electrically connected to the external conductive member, a cover plate assembly.

2. The content of the first metal in the first composite layer increases in a direction from a position away from the first metal layer toward a position closer to the first metal layer, The cover plate assembly according to Claim 1.

3. The content of the second metal in the second composite layer increases in a direction from a position away from the second metal layer toward a position closer to the second metal layer, The cover plate assembly according to Claim 1.

4. The content of the second metal in the second composite layer is more than the content of the first metal in the first composite layer, The cover plate assembly according to Claim 1.

5. The third metal layer at least covers a part of a surface of the first metal layer close to the second metal layer or a part of a surface of the second metal layer close to the first metal layer, The cover plate assembly according to Claim 1.

6. The third metal layer completely covers the larger one of the surface of the first metal layer close to the second metal layer and the surface of the second metal layer close to the first metal layer, The cover plate assembly according to Claim 5.

7. The third metal layer uniformly covers the surface of the first metal layer close to the second metal layer or the surface of the second metal layer close to the first metal layer, The cover plate assembly according to Claim 5.

8. On one surface of the first metal layer and the other surface of the first metal layer and the second metal layer close to the other of the first metal layer and the second metal layer, at least one protrusion is disposed. On the other surface of the first metal layer and the second metal layer close to the one of the first metal layer and the second metal layer, a first fitting hole corresponding to the at least one protrusion is disposed. In the third metal layer, a second fitting hole corresponding to the at least one protrusion is disposed. The at least one protrusion is fitted and connected to the corresponding first fitting hole and the second fitting hole. The cover plate assembly according to claim 1.

9. On the surface of the first metal layer close to the second metal layer, the at least one protrusion is disposed. On the surface of the second metal layer close to the first metal layer, a first fitting hole that fits the at least one protrusion is disposed. In the third metal layer, a second fitting hole that fits the at least one protrusion is disposed. The at least one protrusion is fitted and connected to the corresponding first fitting hole and the second fitting hole. The cover plate assembly according to claim 8.

10. The at least one protrusion is symmetrically distributed on one of the first metal layer and the second metal layer along the central axis of the external conductive member. The first fitting hole is symmetrically distributed on the other of the first metal layer and the second metal layer along the central axis of the external conductive member. The second fitting hole is symmetrically disposed on the third metal layer along the central axis of the external conductive member. The cover plate assembly according to claim 8.

11. The outer surface of the at least one protrusion or the inner surface of the first fitting hole is covered by the third metal layer. The cover plate assembly according to claim 8.

12. Along the radial direction of the external conductive member, in the direction from the direction away from the through hole to the through hole, among the surfaces of the second metal layer close to the first metal layer, the portion exceeding the first metal layer is not covered by the third metal layer. The cover plate assembly according to claim 1.

13. The thickness of the third metal layer is set to be 0.5 μm to 1000 μm. The cover plate assembly according to claim 1.

14. The thickness of the third metal layer is set to be 5 μm to 10 μm. The cover plate assembly according to claim 13.

15. The thickness of the second composite layer is d, and the total thickness of the first composite layer and the second composite layer is a, satisfying the relational expression 0.2a ≤ d ≤ 0.

9. The cover plate assembly according to claim 1.

16. The third metal layer contains at least one of nickel, silver, and tin. The cover plate assembly according to claim 1.

17. The cover plate assembly according to any one of claims 1 to 16, a shell in which the electrode assembly is installed, comprising: One end of the electrode lead-out member in the cover plate assembly is connected to the electrode assembly, the other end passes through the through hole, and is electrically connected to the second metal layer of the cover plate assembly. A battery cell.

18. A battery pack comprising the battery cell according to claim 17.

Images