Battery cell cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell cover plate and a battery cell. The battery cell cover plate comprises a cover plate main body provided with a mounting hole; the pole is arranged in the mounting hole; the riveting piece is riveted with the pole post and then is welded with the pole post; the welding joint of the pole and the riveting piece is filled with the welding filling piece, and the melting point of the welding filling piece is lower than that of the pole and that of the riveting piece. The welding filling piece is filled at the welding joint of the pole and the riveting piece, so that the pole and the riveting piece can be wrapped after the welding filling piece is heated and melted, and the welding strength of the pole and the riveting piece is ensured; the melting point of the welding filling piece is lower than that of the pole and the riveting piece, so that the welding filling piece cannot generate high temperature after being melted, the influence of thermal deformation of the riveting piece is small, the flatness of the riveting piece is effectively improved, the appearance of the welding area of the pole and the riveting piece is improved, the appearance yield of the cell cover plate is improved, and the production cost is reduced. Therefore, the safety and the yield of the battery cell are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell cover plate and a battery cell. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the use performance and safety of lithium-ion batteries are increasing day by day. The lithium battery cover plate is a key component in the lithium-ion battery, and its functions include welding with the housing to form a sealed cavity, leading out the positive and negative electrodes of the electrode group, and serving as an assembly carrier, etc.

[0003] In traditional cover plates, the pole columns are realized by riveting. Among them, the negative pole column is usually made of pure copper. After assembly, the pole column and the riveted aluminum block are riveted and fixed, and then the riveted aluminum block and the pole column are welded; since copper and aluminum are two different materials, the melting point of copper is relatively high compared to the aluminum material, and a large welding power is required, which is likely to cause welding cracking, welding explosion holes, heat deformation of the riveted aluminum block, poor flatness, blackening and oxidation of copper and aluminum, etc., resulting in a reduction in the yield rate of battery cell production. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a battery cell cover plate and a battery cell to solve the problem that the existing riveted aluminum block and the pole column are made of different materials, and a large welding power is required during welding, which is likely to cause welding cracking, welding explosion holes, heat deformation of the riveted aluminum block, poor flatness, blackening and oxidation of copper and aluminum, etc., resulting in low safety and yield rate of the battery.

[0005] The first aspect of the present invention provides a battery cell cover plate, wherein the battery cell cover plate includes: A cover plate main body, provided with an installation hole; A pole column, disposed in the installation hole; A riveting member, which is riveted to the pole column and then welded; a connection hole is provided on the riveting member, and a convex platform is formed on the inner wall of the connection hole, so that the connection hole is formed into a stepped hole having a first stepped portion and a second stepped portion. The radial dimension of the first stepped portion is d, and the radial dimension of the second stepped portion is d2. After riveting, the circumferential side wall of the part of the pole column expands outward to form a bulging portion, and the radial dimension of the bulging portion is d1, and 0.05 ≤ (d2 - d1) / d ≤ 0.1; A welding filler, filled at the welding joint of the pole column and the riveting member, and the melting point of the welding filler is lower than the melting points of the pole column and the riveting member.

[0006] Preferably, the bulging portion abuts against the convex platform, the first stepped portion is disposed on the side of the riveting member facing the cover plate main body, and the welding filler is disposed on the inner wall side of the second stepped portion.

[0007] Preferably, the pole and the rivet are made of different materials.

[0008] Preferably, the material of the rivet is aluminum, and / or the material of the pole is copper.

[0009] Preferably, the battery cell cover is a negative electrode cover. Preferably, the rivet and the pole are connected by brazing, and the welding filler is a brazing material. Preferably, the pole includes a plate body portion, a column portion and a connecting portion arranged in sequence along the axial direction, the plate body portion is arranged on the side of the cover plate body facing the inside of the battery cell, the column portion is arranged in the mounting hole, the connecting portion is arranged on the side of the cover plate body facing the outside of the battery cell, the expanded portion is formed by expanding outwardly at least part of the circumferential side wall of the connecting portion, and the welding filler is arranged on the outer wall side of the expanded portion.

[0010] Preferably, the cell cover plate further includes: A first insulating member, disposed between the cover plate body and the riveted member, wherein a portion of the first insulating member covers a circumferential side wall of the riveted member; The second insulating member is arranged on a side of the cover plate body facing the inside of the battery cell, and a portion of the second insulating member is sandwiched between the plate body and the cover plate body.

[0011] Preferably, the cell cover plate further includes: A sealing member is sandwiched between the plate body and the cover body, and a portion of the sealing member extends into between the mounting hole and the column body.

[0012] A second aspect of the present invention provides a battery cell, comprising the battery cell cover plate described in any of the above technical solutions.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The cell cover of the present invention is filled with a welding filler at the welding joint of the pole and the riveted part, so that the welding filler can wrap the pole and the riveted part after being heated and melted, so as to ensure the welding strength of the pole and the riveted part; the melting point of the welding filler is lower than the melting point of the pole and the riveted part, so that the welding filler will not generate a high temperature after melting, and the riveted part is less affected by thermal deformation, which effectively improves the flatness of the riveted part, and improves the appearance of the welding area of ​​the pole and the riveted part, and improves the appearance yield of the cell cover, thereby improving the safety and yield rate of the battery cell. In addition, by limiting 0.05≤(d2-d1) / d≤0.1, it is ensured that the welding filler is set in a suitable area space to avoid the situation where the resistance between the pole and the riveted part increases after installation.

[0014] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a cell cover plate provided in an embodiment of the present invention; Figure 2 For along Figure 1 The cross-section taken at AA in the middle; Figure 3 for Figure 2 The enlarged structural diagram at B in the middle; Figure 4 This is a schematic diagram of the structure of the battery cell cover after welding the pole and the riveted piece provided in an embodiment of the present invention.

[0017] Icons: 10-cover body; 11-mounting hole; 20-pole; 201-inflating part; 21-plate body; 22-column body; 23-connecting part; 30-rivet; 31-connecting hole; 311-first step part; 312-second step part; 313-third step part; 40-welding filler; 51-first insulating part; 52-second insulating part; 60-sealing part. DETAILED DESCRIPTION

[0018] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0019] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0020] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0021] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0022] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0023] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0024] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0025] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0026] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0027] According to a first aspect of the present invention, a cell cover is provided, which specifically includes a cover body 10 , a pole 20 , a rivet 30 and a welding filler 40 .

[0028] Hereinafter, the specific structure of the cell cover plate according to the present embodiment as described above will be described.

[0029] In this embodiment, if Figures 1 to 4 As shown, the cover body 10 is formed into a plate-like structure. Specifically, when the battery cell is a blade battery cell or a square battery cell, the cover body 10 can be a rectangular plate-like structure. When the battery cell is a cylindrical battery cell, the cover body 10 can be a circular plate-like structure. The cover body 10 is provided with a mounting hole 11. The mounting hole 11 is a through-hole structure that runs through the cover body 10. The mounting hole 11 can be a circular hole, a polygonal hole, an elliptical hole, or a long hole, etc., which can meet the installation requirements of the pole 20.

[0030] In this embodiment, if Figure 2 and Figure 3As shown, the pole 20 is arranged in the mounting hole 11, and the two ends of the pole 20 in the axial direction extend out of the mounting hole 11 respectively. After the pole 20 is riveted with the rivet 30, part of the circumferential side wall of the pole 20 expands outward to form a swelling portion 201, and the swelling portion 201 is formed at one end of the pole 20 in the axial direction; specifically, the pole 20 includes a plate body portion 21, a columnar portion 22 and a connecting portion 23 arranged in sequence along the axial direction, the plate body portion 21 is arranged on the side of the cover body 10 facing the inside of the battery cell, the plate body portion 21 is a polygonal or circular plate-like structure, etc., for connecting the pole group inside the battery cell, the columnar portion 22 is penetrated through the mounting hole 11, and the connecting portion 23 is arranged on the side of the cover body 10 facing the outside of the battery cell, for connecting the charging and discharging equipment. In this embodiment, the columnar portion 22 and the connecting portion 23 may be circular in cross-section perpendicular to the axis of the pole 20.

[0031] In this embodiment, if Figure 3 and Figure 4 As shown, the rivet 30 is a block structure, and the rivet 30 is riveted to the pole 20 and then welded. Specifically, the rivet 30 is riveted to the connecting portion 23, and through stamping and other processes, at least part of the connecting portion 23 facing the outside of the battery cell is expanded along its radial direction to realize the expanded portion 201 that is riveted and connected with the rivet 30.

[0032] In this embodiment, if Figure 3 and Figure 4 As shown, the welding filler 40 is filled in the welding joint between the pole 20 and the rivet 30. The welding filler 40 is heated and melted through the welding process to wrap the pole 20 and the rivet 30 to ensure the welding strength of the pole 20 and the rivet 30. The melting point of the welding filler 40 is lower than the melting point of the pole 20 and the rivet 30, so that the welding filler 40 will not generate a high temperature after melting, so the rivet 30 is less affected by thermal deformation, effectively improving the flatness of the rivet 30, and improving the appearance of the welding area of ​​the pole 20 and the rivet 30, thereby improving the appearance yield of the battery cover, thereby improving the safety and yield of the battery cell.

[0033] Specifically, the welding filler 40 is disposed on at least a portion of the outer wall side of the connecting portion 23 , and the welding filler 40 is formed in a ring shape to surround the entire circumference of the side wall of the connecting portion 23 .

[0034] Furthermore, if Figure 3As shown, a connecting hole 31 is opened on the rivet 30, and a boss is formed on the inner wall of the connecting hole 31, so that the connecting hole 31 is formed as a stepped hole having a first step portion 311 and a second step portion 312. The first step portion 311 is arranged on the side of the rivet 30 facing the cover plate body 10, and the boss between the pole 20 and the first step portion 311 and the second step portion 312 abuts to form a fixed riveted relationship, and the pole 20 expands toward the direction close to the second step portion 312 to form an expanding portion 201, and the welding filler 40 is arranged between the inner wall side of the second step portion 312 and the outer wall side of the expanding portion 201.

[0035] Insufficient space in the area where the welding filler 40 is set will increase the resistance between the pole 20 and the rivet 30. Too small a space will affect the melting and filling of the welding filler 40 and cause excessive resistance. In this embodiment, Figure 4 As shown, 0.05≤(d2-d1) / d≤0.1, wherein d is the radial dimension of the first step portion 311, d2 is the radial dimension of the second step portion 312, and d1 is the radial dimension of the expanded portion 201, so that the resistance value R between the pole 20 and the rivet 30 after welding is ≤0.035mΩ.

[0036] Next, multiple cell cover plates with the same d and d1 dimensions but different d2 dimensions are assembled, and the resistance value between the rivet 30 and the pole 20 after assembly is tested to verify whether the limited range of 0.05≤(d2-d1) / d≤0.1 can meet the requirement of R≤0.035mΩ. The test results are shown in Tables 1 to 3 below.

[0037] Table 1

[0038] Table 2

[0039] Table 3

[0040] Referring to Tables 1 to 3 above, it can be seen that in Examples 1-1 to 1-5, Examples 2-1 to 2-5 and Examples 3-1 to 3-5, the parameters of (d2-d1) / d are all within the range of 0.05 to 0.1, and the resistance value R is less than or equal to 0.035 mΩ, thereby ensuring that the current capacity of the pole 20 meets the use requirements of the battery cell, while in Comparative Examples 1-1 to 1-4, Examples 2-1 to 2-4 and Examples 3-1 to 3-4, the parameters of (d2-d1) / d are all less than 0.05 or greater than 0.1, and the resistance value R is greater than 0.035 mΩ, and therefore does not meet the requirements.

[0041] Furthermore, in this embodiment, if Figure 3 As shown, the connection hole 31 further includes a third step portion 313, which is disposed on the side of the second step portion 312 facing away from the first step portion 311, so that the first step portion 311, the second step portion 312 and the third step portion 313 are arranged in sequence along the axis of the connection hole 31. The third step portion 313 can reduce the height of the weld formed after welding protruding from the outer surface of the side of the rivet 30 facing away from the cover plate body 10 to a certain extent, which helps to improve the flatness of the rivet 30. In this embodiment, the material of the pole 20 is different from that of the rivet 30, that is, the pole 20 and the rivet 30 have different melting points, and the melting point of the welding filler 40 is lower than the relatively lower melting point of the pole 20 and the rivet 30, so as to ensure that the welding filler 40 will not affect the pole 20 or the rivet 30 when it is heated and melted.

[0042] Specifically, in this embodiment, the material of the rivet 30 is aluminum, and / or the material of the pole 20 is copper.

[0043] Preferably, the cell cover is a negative electrode cover, the pole on the negative electrode cover is a negative electrode pole, and the material of the pole 20 on the negative electrode cover is usually different from the material of the rivet 30 . In a preferred embodiment, the rivet 30 and the pole 20 are brazed together, and the welding filler 40 is a brazing filler. The brazing filler is an alloy material with metal as the main component. The surface tension of the brazing filler is heated to melt it onto the surface of the rivet 30 and the pole 20. After cooling, the rivet 30 and the pole 20 are fixedly connected, thereby ensuring that the pole 20 can withstand a higher push-pull force and ensuring that the resistance value R between the pole 20 and the rivet 30 meets the requirements. The following comparative test is conducted on a plurality of cell cover plates with the same d and d1 dimensions but different d2 dimensions by conventional welding and brazing assembly to verify whether the limited range of 0.05≤(d2-d1) / d≤0.1 can satisfy the requirement of the resistance value R≤0.035mΩ between the rivet 30 and the pole 20, and the assembled pole 20 is subjected to a force test to determine the maximum push-pull force F (in N) that the pole 20 can withstand, and the direction of the push-pull force F is the axial direction of the pole 20. The test results are shown in Table 4 below.

[0044] Table 4

[0045] As shown in Examples 4-1 to 4-3 in Table 4, compared with the conventional welding method, brazing can ensure that the resistance value R is less than or equal to 0.035 mΩ under the condition of the same size, and the brazing connection enables the pole 20 to withstand a greater push-pull force, so the brazing connection between the rivet 30 and the pole 20 can obtain a cell cover with better performance. Figures 1 to 4 As shown, the cell cover also includes a first insulating member 51 and a second insulating member 52. The first insulating member 51 and / or the second insulating member 52 may be made of PP (polypropylene) or PPS (polyphenylene sulfide). Specifically, the first insulating member 51 is disposed between the cover body 10 and the rivet 30. Part of the first insulating member 51 is coated on the circumferential side wall of the rivet 30 to provide insulation protection for the cover body 10 to prevent short circuit caused by metal overlap. The first insulating member 51 is provided with a through hole for the pole 20 to pass through. Part of the first insulating member 51 extends between the inner wall of the mounting hole 11 and the side wall of the pole 20 to prevent the pole 20 from contacting the cover body 10 to a certain extent. The first insulating member 51 is disposed in one-to-one correspondence with the pole 20.

[0046] More specifically, if Figures 2 to 4 As shown, the second insulating member 52 is arranged on the side of the cover body 10 facing the inside of the battery cell. When the cover body 10 is a rectangular sheet-mounted structure, the second insulating member 52 can be formed into a strip structure extending along the length direction of the cover body 10. Part of the second insulating member 52 is clamped between the plate body 21 and the cover body 10, thereby further forming insulation protection for the cover body 10.

[0047] In addition, in this embodiment, Figures 2 to 4 As shown, the cell cover also includes a seal 60, which can be a seal ring made of fluororubber. The seal ring is formed into an annular structure to be sleeved on the circumferential side wall of the column part 22 of the pole 20. In the thickness direction of the cover body 10, the seal 60 is sandwiched between the plate body 21 and the cover body 10, so as to ensure the sealing of the cell cover assembly and avoid leakage and seepage of the cell. Part of the seal 60 extends between the mounting hole 11 and the column part 22 to fill the gap between the mounting hole 11 and the main body to ensure the sealing reliability. Preferably, the first insulating member 51 and the second insulating member 52 are both crimped with the seal 60 to completely separate the pole 20 from the cover body 10 while ensuring the sealing, thereby meeting the insulation requirements of the cover body 10.

[0048] In addition, in this embodiment, Figure 1 As shown, the cover body 10 is also provided with an injection hole, which is a through-hole structure penetrating the cover body 10. After the battery cover and the shell are assembled, electrolyte can be injected into the battery cell through the injection hole. After the injection is completed, the injection hole can be closed.

[0049] According to a battery cell cover provided by the present invention, a welding filler is filled at the welding joint between the pole and the rivet, so that the welding filler can wrap the pole and the rivet after being heated and melted, so as to ensure the welding strength of the pole and the rivet; the melting point of the welding filler is lower than the melting point of the pole and the rivet, so that the welding filler does not generate a high temperature after melting, the rivet is less affected by thermal deformation, the flatness of the rivet is effectively improved, and the appearance of the welding area of ​​the pole and the rivet is improved, thereby improving the appearance yield of the battery cell cover, thereby improving the safety and yield of the battery cell.

[0050] A battery cell provided according to the present invention comprises the battery cell cover as described above. The pole and riveted welding structure in the battery cell cover not only ensure the welding connection strength but also improve the appearance yield, thus also being able to improve the safety and yield of the battery cell to a certain extent.

[0051] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell cover, characterized in that: The battery cover plate comprises: The cover plate body is provided with a mounting hole; A pole, arranged in the mounting hole; A rivet is riveted to the pole and then welded; a connection hole is formed on the rivet, and a boss is formed on the inner wall of the connection hole, so that the connection hole is formed into a stepped hole with a first step portion and a second step portion, the radial dimension of the first step portion is d, the radial dimension of the second step portion is d2, and the circumferential side wall of the pole after riveting is expanded outward to form a bulging portion, and the radial dimension of the bulging portion is d1, 0.05≤(d2-d1) / d≤0.1; A welding filler is filled in the welding joint between the pole and the riveted piece, and the melting point of the welding filler is lower than the melting points of the pole and the riveted piece.

2. The cell cover plate according to claim 1, characterized in that: The first stepped portion is disposed on a side of the rivet member facing the cover plate body, and the welding filler is disposed on an inner wall side of the second stepped portion.

3. The cell cover plate according to claim 1, characterized in that: The pole and the rivet are made of different materials.

4. The cell cover plate according to claim 1, characterized in that: The material of the rivet is aluminum, and / or the material of the pole is copper.

5. The cell cover plate according to claim 1, characterized in that: The battery cell cover is a negative electrode cover.

6. The cell cover plate according to claim 1, characterized in that: The rivet piece and the pole are connected by brazing, and the welding filler is a brazing material.

7. The cell cover plate according to claim 1, characterized in that: The pole includes a plate body portion, a column portion and a connecting portion arranged in sequence along the axial direction, the plate body portion is arranged on the side of the cover plate body facing the inside of the battery cell, the column portion is arranged in the mounting hole, the connecting portion is arranged on the side of the cover plate body facing the outside of the battery cell, the expanded portion is formed by expanding outwardly at least a portion of the circumferential side wall of the connecting portion, and the welding filler is arranged on the outer wall side of the expanded portion.

8. The cell cover plate according to claim 7, characterized in that: The battery cover plate also includes: A first insulating member, disposed between the cover plate body and the riveted member, wherein a portion of the first insulating member covers a circumferential side wall of the riveted member; The second insulating member is arranged on a side of the cover plate body facing the inside of the battery cell, and a portion of the second insulating member is sandwiched between the plate body and the cover plate body.

9. The cell cover plate according to claim 7, characterized in that: The battery cover plate also includes: A sealing member is sandwiched between the plate body and the cover body, and a portion of the sealing member extends into between the mounting hole and the column body.

10. A battery cell, characterized in that: The invention comprises a cell cover plate as described in any one of claims 1 to 9.

Images