Battery welding structure, cylindrical battery and battery module

Abstract

The utility model provides a battery welding structure, a cylindrical battery and a battery module. The battery welding structure comprises a battery cell, a negative tab, a shell and a bottom cover, the negative tab comprises a first connecting part and a second connecting part which are connected with each other, the first connecting part is connected to a negative plate of the battery cell, one end of the shell is provided with a first opening, the other end of the shell is provided with a second opening, and the second opening is connected to the bottom cover. The shell is provided with a first opening, the bottom cover is located in the first opening, the outer periphery of the bottom cover is connected with the inner wall of the shell, the battery cell is installed in the shell, part of the second connecting part is located between the side wall of the bottom cover and the inner wall of the shell, and the second connecting part is welded to the bottom cover and the shell through laser. And the second opening is used for mounting a top cover. Due to the fact that the shell is of the two-way structure, and the second connecting part is welded to the outer periphery of the bottom cover and the inner wall of the shell, the welding position of the second connecting part and the bottom cover or the shell can be visually detected.

Description

Technical Field

[0001] The present disclosure relates to the field of battery welding, and particularly to a battery welding structure, a cylindrical battery, and a battery module. Background Art

[0002] During the production process of a cylindrical battery, the negative electrode tab connects the negative electrode sheet to the steel shell to ensure that the current inside the battery can effectively conduct from the negative electrode sheet to the outside of the battery for charging and discharging operations. In traditional technology, the negative electrode tab of a semi-sealed cylindrical battery is welded to the inner side of the steel shell by resistance welding. After welding is completed, an on-line tensile test needs to be carried out to determine whether the welding is qualified, so as to avoid the phenomenon that the connection of the tab becomes unstable due to vibration during later production or transportation, resulting in an increase in internal resistance.

[0003] However, since the steel shell and the bottom cover are of an integral structure, and the negative electrode tab is welded to the inner side of the steel shell by resistance welding, if there is a lack of fusion welding, it cannot be detected by the on-line tensile test. It is necessary to perform a metallographic analysis offline to detect whether there is a penetration depth in the welding, and thus determine whether there is a lack of fusion welding. Metallographic analysis is mainly the analysis of microscopic materials, which is not only a cumbersome process, but also requires each battery to be placed in a specific device for detection. Therefore, there is a problem of great difficulty in detecting lack of fusion welding.

[0004] Therefore, there is an urgent need for a battery structure with high convenience for detecting lack of fusion welding. Summary of the Utility Model

[0005] The purpose of the present disclosure is to overcome the deficiencies in the prior art and provide a battery welding structure, a cylindrical battery, and a battery module that are convenient for quickly detecting lack of fusion welding of the negative electrode tab.

[0006] The purpose of the present disclosure is achieved by the following technical solutions:

[0007] A battery welding structure includes:

[0008] A battery cell and at least one negative electrode tab. The negative electrode tab includes a first connection portion and a second connection portion connected to each other. The first connection portion is connected to the negative electrode sheet of the battery cell.

[0009] The battery welding structure further includes a housing and a bottom cover. One end of the housing is provided with a first opening, and the other end of the housing is provided with a second opening. The bottom cover is located in the first opening, and the outer peripheral edge of the bottom cover is connected to the inner wall of the housing. The battery cell is installed in the housing. A part of the second connection portion is located between the side wall of the bottom cover and the inner wall of the housing. The second connection portion is laser welded to the bottom cover and the housing respectively. The second opening is used for installing a top cover.

[0010] In one embodiment, at least a part of the second connection portion is located outside the housing.

[0011] In one embodiment, one end of the second connecting portion away from the battery cell is flush with the port of the second opening.

[0012] In one embodiment, the first opening is circular.

[0013] In one embodiment, the second opening is circular.

[0014] In one embodiment, the battery welding structure further includes at least one positive tab, and the positive tab is connected to the positive electrode plate of the battery cell.

[0015] In one embodiment, the first connecting portion and the second connecting portion are of an integrally formed structure. In one embodiment, the number of negative tabs is multiple, and the multiple negative tabs are arranged at intervals along the outer peripheral edge of the battery cell, and the end of each negative tab is clamped and connected between the bottom cover and the housing.

[0016] A cylindrical battery includes a top cover and the battery welding structure according to any one of the above embodiments, and the top cover is welded to the second opening.

[0017] A battery module includes the cylindrical battery according to any one of the above embodiments.

[0018] Compared with the prior art, the present disclosure has at least the following advantages:

[0019] In the above battery welding structure, the first connecting portion and the second connecting portion of the negative tab are fixedly connected, the first connecting portion is connected to the negative electrode plate of the battery cell, the first opening and the second opening are respectively formed at both ends of the housing, a part of the second connecting portion is located between the bottom cover and the inner wall of the housing, and the second connecting portion is respectively laser welded to the bottom cover and the housing. Since the housing is a double-pass structure and the second connecting portion is welded to the outer peripheral edge of the bottom cover and the inner wall of the housing, the welding portion of the second connecting portion with the bottom cover or the housing can be visually detected, and then it can be judged whether there is a false weld at the welding portion, that is, it is not necessary to detect by metallographic analysis. In this way, the detection of false welding of the negative tab is more convenient, and this structure has high anti-vibration strength. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained according to these drawings without creative efforts.

[0021] Figure 1 It is a schematic structural diagram of a battery welding structure according to an embodiment;

[0022] Figure 2 is Figure 1 a schematic structural view of the shown housing;

[0023] Figure 3 is Figure 1 a welding assembly schematic view of the shown battery welding structure. Specific embodiments

[0024] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present disclosure can be understood more thoroughly and comprehensively.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a middle element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] The present disclosure provides a battery welding structure, including an electric core, a negative electrode tab, a housing and a bottom cover. The negative electrode tab includes a connected first connection portion and a second connection portion. The first connection portion is connected to the negative electrode plate of the electric core. One end of the housing is provided with a first opening, and the other end of the housing is provided with a second opening. The bottom cover is located in the first opening, and the outer peripheral edge of the bottom cover is connected to the inner wall of the housing. The electric core is installed in the housing. Part of the second connection portion is located between the side wall of the bottom cover and the inner wall of the housing. The second connection portion is laser welded to the bottom cover and the housing respectively. The second opening is used for installing a top cover.

[0028] In the above battery welding structure, the first connecting portion and the second connecting portion of the negative electrode tab are fixedly connected. The first connecting portion is connected to the negative electrode plate of the battery cell. First openings and second openings are respectively formed at two ends of the housing. A part of the second connecting portion is located between the bottom cover and the inner wall of the housing. The second connecting portion is laser welded to the bottom cover and the housing respectively. Since the housing is a double-pass structure and the second connecting portion is welded to the outer peripheral edge of the bottom cover and the inner wall of the housing, the welding part of the second connecting portion with the bottom cover or the housing can be visually detected, and then it can be judged whether there is a false weld at the welding part, that is, there is no need to detect by metallographic analysis. In this way, the detection of false welding of the negative electrode tab is more convenient, and this structure has high anti-vibration strength.

[0029] To better understand the technical solutions and beneficial effects of the present disclosure, the following further describes the present disclosure in detail with specific embodiments:

[0030] As Figure 1 and Figure 2 shown, a battery welding structure 10 of an embodiment includes a battery cell 100, a negative electrode tab 200, a housing 300 and a bottom cover 400. The negative electrode tab 200 includes a connected first connecting portion 210 and a second connecting portion 220. The first connecting portion 210 is connected to the negative electrode plate of the battery cell 100. A first opening 310 is formed at one end of the housing 300, and a second opening 320 is formed at the other end of the housing 300. The bottom cover 400 is located in the first opening 310. The outer peripheral edge of the bottom cover 400 is connected to the inner wall of the housing 300. The battery cell 100 is installed in the housing 300. A part of the second connecting portion 220 is located between the side wall of the bottom cover 400 and the housing 300. The second connecting portion 220 is laser welded to the bottom cover 400 and the housing 300 respectively. The second opening 320 is used for welding with a top cover.

[0031] In this embodiment, a first opening 310 and a second opening 320 are respectively formed at both ends of the housing 300, that is, the housing 300 is a double-pass structure. Among them, the second opening 320 is welded to the top cover, and the first opening 310 is used to be welded to the bottom cover 400. First, the first connecting portion 210 of the negative electrode tab 200 is first welded to the negative electrode plate of the battery cell 100, and the battery cell 100 and the negative electrode tab 200 are placed into the housing 300. At this time, the second connecting portion 220 is located between the bottom cover 400 and the housing 300. Then, through laser side welding, the second connecting portion 220 is welded to the outer periphery of the bottom cover 400 and the inner wall of the housing 300, and at the same time, the outer periphery of the bottom cover 400 and the inner wall of the housing 300 are welded to fix the bottom cover 400 and the housing 300. Specifically, since the housing 300 is a double-pass structure, the second connecting portion 220 is welded to the bottom cover 400 and the housing 300 by laser side welding, so that the welded portion of the second connecting portion 220 can be visually observed after welding to determine whether there is a false weld. Further, the second connecting portion 200 is respectively welded to the bottom cover 400 and the housing 300, so that the connection strength of the negative electrode tab 200 is relatively high, and the vibration resistance of the battery is improved.

[0032] For the above-mentioned battery welding structure 10, the first connecting portion 210 and the second connecting portion 220 of the negative electrode tab 200 are fixedly connected. The first connecting portion 210 is connected to the negative electrode plate of the battery cell 100. A first opening 310 and a second opening 320 are respectively formed at both ends of the housing 300. A part of the second connecting portion 220 is located between the housing 300 and the bottom cover 400. The second connecting portion 220 is respectively laser welded to the bottom cover 400 and the housing 300. Since the housing 300 is a double-pass structure and the second connecting portion 220 is welded to the outer periphery of the bottom cover 400 and the inner wall of the housing 300, the welded portion of the second connecting portion with the bottom cover or the housing can be visually detected, and then it can be determined whether there is a false weld at the welded portion, that is, it is not necessary to detect by metallographic analysis. In this way, the detection of false welding of the negative electrode tab is more convenient, and this structure has high vibration resistance.

[0033] In one embodiment, at least a part of the second connecting portion 220 is located outside the housing 300. In this embodiment, the second connecting portion 220 extends outside the housing. A part of the second connecting portion 220 is located between the housing 300 and the bottom cover 400, so that a part of the negative electrode tab 200 is located outside the housing 300, which is convenient for directly observing the false welding of the laser side welding between the negative electrode tab 200 and the bottom cover 400, and at the same time, it is also convenient for directly observing the false welding of the laser side welding between the negative electrode tab 200 and the housing 300.

[0034] In another embodiment, after the laser welding is completed, the part of the second connecting portion 220 extending outside the housing 300 is cut off to make the battery structure more flat and more convenient for detecting whether there is a false weld in the negative electrode tab 200.

[0035] In one embodiment, the end of the second connecting portion 220 away from the battery cell 100 is flush with the port of the second opening 320. In this embodiment, the length of the second connecting portion 220 is just flush with the port of the second opening 320, that is, the end of the second connecting portion 220 away from the first connecting portion 210 is just located between the bottom cover 400 and the housing 300. That is, after laser welding, there is no need to cut off the second connecting portion 220 anymore.

[0036] In one embodiment, the first connecting portion 210 and the second connecting portion 220 are of an integrally formed structure. In this embodiment, the first connecting portion 210 and the second connecting portion 220 are formed by integral stamping, so that the structural strength of the negative electrode tab 200 is higher.

[0037] As Figure 1 and Figure 2 shown, in one embodiment, the first opening 310 is circular in shape to adapt to the shape of the bottom cover 400, so that the connection strength between the housing 300 and the bottom cover 400 is higher.

[0038] As Figure 1 and Figure 2 shown, in one embodiment, the second opening 320 is circular in shape to adapt to the shape of the top cover, so that the connection strength between the housing 300 and the top cover is higher.

[0039] In one embodiment, the end of the second connecting portion 220 away from the first connecting portion 210 is flush with the bottom cover 400. It can be understood that after the second connecting portion 220 is welded to the outer periphery of the bottom cover 400 and the inner wall of the housing 300, the redundant second connecting portion 220 extending out of the housing 300 is cut off, so that the second connecting portion 220 is flush with the bottom cover 400, thereby making the battery structure more flat.

[0040] In one embodiment, the number of the negative electrode tabs 200 is multiple, and the multiple negative electrode tabs 200 are arranged at intervals along the outer periphery of the battery cell 100, and the end of each negative electrode tab 200 is clamped and connected between the bottom cover and the housing 300. It can be understood that by providing multiple negative electrode tabs 200, the power density and fast charging performance of the battery are improved, and the first connecting portion 210 of each negative electrode tab 200 is welded to the outer periphery of the battery cell 100 at intervals, and the second connecting portion 220 is clamped and welded between the bottom cover 400 and the housing 300, so that the connection strength of each negative electrode tab 200 is higher.

[0041] In one embodiment, the battery cell 100 includes a positive electrode plate, a separator, and a negative electrode plate. The positive electrode plate, the separator, and the negative electrode plate are stacked and wound. The structure of the negative electrode plate located on the outside is provided with a welding area, and the first connecting portion 210 is welded to the welding area. It can be understood that the welding area is located at the end of the negative electrode plate. After the negative electrode plate is wound, the welding area is located on the outside of the battery cell 100. The first connecting portion 210 is welded to the welding area to conduct the negative electrode tab 200 and the negative electrode plate.

[0042] In one embodiment, the battery welding structure 10 further includes a positive electrode tab 500, and the positive electrode tab 500 is welded to the positive electrode plate. It can be understood that the positive electrode tab 500 is welded and conducted with the positive electrode plate to form a circuit for the battery cell 100.

[0043] The present application also provides a cylindrical battery, including a top cover and the battery welding structure 10 described in any one of the above embodiments. The top cover is welded to the second opening 320 to fix the top cover and the second opening 320.

[0044] The present application also provides a battery module, including the cylindrical battery described in any one of the above embodiments.

[0045] Compared with the prior art, the present disclosure has at least the following advantages:

[0046] In the above battery welding structure 10, the first connecting portion 210 and the second connecting portion 220 of the negative electrode tab 200 are fixedly connected. The first connecting portion 210 is connected to the negative electrode plate of the battery cell 100. The two ends of the housing 300 are respectively provided with a first opening 310 and a second opening 320. A part of the second connecting portion 220 is located between the housing 300 and the bottom cover 400. The second connecting portion 220 is respectively laser welded to the bottom cover 400 and the housing 300. Since the housing 300 is a double-pass structure, and the second connecting portion 220 is welded to the outer peripheral edge of the bottom cover 400 and the inner wall of the housing 300, the welding parts of the second connecting portion to the bottom cover or the housing can be visually detected, and then it can be judged whether there is a virtual weld at the welding parts, that is, there is no need to detect by metallographic analysis. In this way, the detection of the virtual weld of the negative electrode tab is more convenient, and this structure has high anti-vibration strength.

[0047] The above embodiments only represent several implementation manners of the present disclosure. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several deformations and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent should be subject to the appended claims.

Claims

1. A battery welding structure, comprising a battery cell and at least one negative electrode ear, wherein the negative electrode ear comprises a first connecting portion and a second connecting portion connected to each other, wherein the first connecting portion is connected to the negative electrode sheet of the battery cell, characterized in that: The battery welding structure also includes a shell and a bottom cover. A first opening is opened at one end of the shell and a second opening is opened at the other end of the shell. The bottom cover is located in the first opening. The outer periphery of the bottom cover is connected to the inner wall of the shell. The battery cell is installed in the shell. The second connecting portion is located between the side wall of the bottom cover and the inner wall of the shell. The second connecting portion is laser welded to the bottom cover and the shell respectively. The second opening is used to install the top cover.

2. The battery welding structure according to claim 1, characterized in that: At least a portion of the second connecting portion is located outside the housing.

3. The battery welding structure according to claim 1, characterized in that: One end of the second connection portion away from the battery core is flush with a port of the second opening.

4. The battery welding structure according to claim 1, characterized in that: The first opening is circular in shape.

5. The battery welding structure according to claim 1, characterized in that: The second opening is circular in shape.

6. The battery welding structure according to claim 1, characterized in that: The battery welding structure further includes at least one positive electrode tab, which is connected to the positive electrode sheet of the battery cell.

7. The battery welding structure according to claim 1, characterized in that: The first connecting portion and the second connecting portion are an integrally formed structure.

8. The battery welding structure according to claim 1, characterized in that: There are multiple negative electrode ears, which are spaced apart along the outer periphery of the battery cell, and the end of each negative electrode ear is clamped and connected between the bottom cover and the shell.

9. A cylindrical battery, characterized in that: The battery welding structure comprises a top cover and any one of claims 1 to 8, wherein the top cover is welded to the second opening.

10. A battery module, characterized in that: Includes the cylindrical battery as described in claim 9.

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