Welding structure, single battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and provides a welding structure, a single battery and a battery pack. The welding structure comprises an electrode assembly, a shell and a confluence plate. The shell comprises a barrel body and a bottom plate. The electrode assembly is arranged in the cylinder body. The bottom plate and the first electrode of the electrode assembly are arranged at intervals. The bus plate is located between the base plate and the first pole of the electrode assembly. And a welding part protruding towards the direction of the bottom plate is arranged on the peripheral side of the confluence plate. Wherein the confluence plate is welded with the first pole of the electrode assembly. The welding part is welded to the bottom plate. Therefore, the welding area of the confluence plate and the bottom plate can be arranged at the edge position so as to avoid the welding position of the bottom plate and the electric connecting piece, and the welding area of the bottom plate and the electric connecting piece is ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to welding structures, single cells, and battery packs. Background Technology

[0002] In related technologies, the negative electrode busbar of a multi-tab battery cell is typically welded to the center of the casing base plate. However, during battery module assembly, electrical connectors also need to be welded to the center of the base plate to enable series or parallel connections between individual cells. This results in the welding position of the negative electrode busbar to the base plate at least partially overlapping with the welding position between the base plate and the electrical connector, thus occupying the welding space between the base plate and the electrical connector and affecting subsequent welding processes. Utility Model Content

[0003] The embodiments of this utility model provide a welding structure, a single battery cell, and a battery pack, which can set the welding area between the busbar and the base plate at the edge position to avoid the welding position between the base plate and the electrical connection piece, thus ensuring the welding area between the base plate and the electrical connection piece.

[0004] In a first aspect, embodiments of the present invention provide a welding structure, comprising:

[0005] Electrode assembly;

[0006] The housing includes a cylindrical body and a bottom plate, the electrode assembly is disposed inside the cylindrical body, and the bottom plate is spaced apart from the first electrode of the electrode assembly;

[0007] A busbar is located between the base plate and the first electrode of the electrode assembly. The busbar has a welding portion protruding towards the base plate on its periphery. The busbar is welded to the first electrode of the electrode assembly, and the welding portion is welded to the base plate.

[0008] In one embodiment, the thickness of the base plate is D1, and the thickness of the welded part is D2, satisfying: 0 < D1 / D2 < 3.

[0009] In one embodiment, the thickness of the base plate is D1 and the thickness of the cylinder body is D3, satisfying: 0.44≤D3 / D1≤1.

[0010] In one embodiment, the welding part is welded to the base plate to form a weld line on the base plate, the width of the weld line being D4, satisfying: 0.15 mm ≤ D4 ≤ 0.25 mm.

[0011] In one embodiment, the bonding wire includes at least two spaced-apart arc segments, or the bonding wire is configured as a ring.

[0012] In one embodiment, the welding structure further includes:

[0013] A sleeve is fitted over the outside of the cylinder body, the sleeve having an extension bent to the bottom plate, the extension covering the welding wire.

[0014] In one embodiment, the welding structure further includes:

[0015] An anti-corrosion layer is attached to the base plate and covers the connection between the base plate and the extension.

[0016] In one embodiment, the anti-corrosion layer has an adhesive layer on the side facing the base plate, and the adhesive layer is bonded to the base plate and the extension.

[0017] In one embodiment, the height difference between the welded part and the manifold is δ, which satisfies: 0.05 mm ≤ δ ≤ 0.15 mm.

[0018] Secondly, embodiments of this utility model provide a single-cell battery, including the welding structure described above.

[0019] Thirdly, embodiments of the present invention provide a battery pack, including the single battery cells as described above.

[0020] The beneficial effects of the embodiments of this utility model are as follows:

[0021] In this embodiment of the invention, a welding portion protruding towards the base plate is provided on the periphery of the busbar. This welding portion is used to weld the busbar to the base plate, thereby positioning the welding area between the busbar and the base plate at the edge of the base plate. This avoids the welding position between the base plate and the electrical connector, ensuring a sufficient welding area between the base plate and the electrical connector. The busbar is welded to the electrode assembly at its center. Welding the center of the busbar to the electrode assembly may cause deformation in the edge area of ​​the busbar. By making the welding portion protrude towards the base plate, the shape of the protrusion can mitigate the deformation of the welding portion, preventing gaps between the welding portion and the base plate that could result in a weak weld. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is one of the cross-sectional views of the welded structure provided in the embodiments of this utility model;

[0024] Figure 2 This is a second cross-sectional view of the welded structure provided in an embodiment of this utility model;

[0025] Figure 3 This is a schematic diagram of the structure of the busbar provided in an embodiment of this utility model;

[0026] Figure 4 This is one of the structural schematic diagrams of the bonding wire provided in the embodiments of this utility model;

[0027] Figure 5 This is one of the structural schematic diagrams of the bonding wire provided in the embodiments of this utility model.

[0028] Figure label:

[0029] 10-Electrode assembly, 20-Housing shell, 210-Cylinder body, 220-Base plate, 30-Manifold, 310-Welding part, 40-Welding wire, 50-Sleeve, 510-Extension part, 60-Anti-corrosion layer. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0031] like Figures 1 to 5 As shown, this application embodiment provides a welding structure. The welding structure includes an electrode assembly 10, a housing 20, and a manifold 30. The housing 20 includes a cylindrical body 210 and a base plate 220. The electrode assembly 10 is disposed within the cylindrical body 210. The base plate 220 is spaced apart from the first electrode of the electrode assembly 10. The manifold 30 is located between the base plate 220 and the first electrode of the electrode assembly 10. A welding portion 310 protruding towards the base plate 220 is provided on the periphery of the manifold 30. The manifold 30 is welded to the first electrode of the electrode assembly 10. The welding portion 310 is welded to the base plate 220.

[0032] In this embodiment, a welding portion 310 protruding towards the base plate 220 is provided on the periphery of the busbar 30. This welding portion 310 is used to weld the busbar 30 to the base plate 220, thereby positioning the welding area between the busbar 30 and the base plate 220 at the edge of the base plate 220. This avoids the welding position between the base plate 220 and the electrical connector, ensuring a sufficient welding area between the base plate 220 and the electrical connector. The busbar 30 is welded to the electrode assembly 10 at its center. Welding the center of the busbar 30 to the electrode assembly 10 may cause deformation in the edge area of ​​the busbar 30. By making the welding portion 310 protrude towards the base plate 220, the shape of this protrusion can mitigate the deformation of the welding portion 310, preventing gaps between the welding portion 310 and the base plate 220 and thus preventing incomplete welds.

[0033] Electrode assembly 10 is the core inside a single cell. Housing 20 is the steel shell outside the single cell. Base plate 220 and cylinder body 210 can be integrally formed. Busbar 30 serves as the first electrode of electrode assembly 10.

[0034] It should be noted that the first electrode of the electrode assembly 10 can be either the negative electrode or the positive electrode of the electrode assembly 10.

[0035] The welding part 310 is integrally formed with the manifold 30. For example, the welding part 310 can be formed by stamping on the edge of the welding pad.

[0036] The welding structure in this application is particularly suitable for cylindrical batteries. Therefore, the busbar 30 is typically circular, and the welding portion 310 is typically annular, with the inner diameter of the welding portion 310 equal to the diameter of the busbar 30. Correspondingly, the body 210 is cylindrical, and the base plate 220 is circular.

[0037] like Figure 1 As shown, in some embodiments, the thickness of the base plate 220 is D1. The thickness of the welded portion 310 is D2, satisfying: 0 < D1 / D2 < 3.

[0038] Understandably, when welding part 310 is welded to base plate 220, welding will be performed on the side of base plate 220 away from welding part 310. The laser will melt base plate 220 and form a connection with welding part 310. When the ratio D1 / D2 between the thickness D1 of base plate 220 and the thickness D2 of welding part 310 is greater than or equal to 3, the thickness of welding part 310 will be too small, making welding part 310 easy to weld through, resulting in cell leakage.

[0039] In this embodiment, the ratio D1 / D2 between the thickness D1 of the base plate 220 and the thickness D2 of the welded portion 310 is kept within the range of 0 to 3 to prevent the thickness of the welded portion 310 from being too small. This prevents the welded portion 310 from being burned through, and prevents cell leakage while ensuring reliable welding between the base plate 220 and the welded portion 310.

[0040] The thickness of the busbar 30 is the same as the thickness of the welded part 310.

[0041] In some embodiments, the ratio D1 / D2 between the thickness D1 of the base plate 220 and the thickness D2 of the welded part 310 can be 0.5, 1, 1.5, 2, 2.5, or any value between the two, as long as it can prevent the welded part 310 from being welded through.

[0042] For example, the thickness D1 of the base plate 220 is set to 0.5 mm. The thickness D2 of the welded part 310 is set to 0.2 mm. In this case, the ratio D1 / D2 between the thickness D1 of the base plate 220 and the thickness D2 of the welded part 310 is 2.5.

[0043] In some embodiments, the thickness D1 of the base plate 220 is greater than the thickness D2 of the weld portion 310. In this case, the ratio D1 / D2 between the thickness D1 of the base plate 220 and the thickness D2 of the weld portion 310 is greater than 1. By reasonably selecting the thickness D1 of the base plate 220 and the thickness D2 of the weld portion 310 during the design phase, it is possible to prevent the weld portion 310 from being burned through. For example, the thickness D1 of the base plate 220 can be set to 0.55 mm, and the thickness D2 of the weld portion 310 can be set to 0.5 mm.

[0044] In some embodiments, the thickness D1 of the base plate 220 is less than the thickness D2 of the weld portion 310. In this case, the thickness D2 of the weld portion 310 can be designed to be larger to prevent the weld portion 310 from being welded through. For example, the thickness D1 of the base plate 220 can be set to 0.4 mm, and the thickness D2 of the weld portion 310 can be set to 0.5 mm.

[0045] In some embodiments, the thickness D1 of the base plate 220 is equal to the thickness D2 of the welded portion 310. For example, the thickness D1 of the base plate 220 is set to 0.5 mm, and the thickness D2 of the welded portion 310 is also set to 0.5 mm.

[0046] like Figure 1 As shown, in some embodiments, the thickness of the base plate 220 is D1, and the thickness of the cylinder body 210 is D3. This satisfies the condition: 0.44 ≤ D3 / D1 ≤ 1.

[0047] It is understandable that the thickness D1 of the base plate 220 is greater than or equal to the thickness D3 of the body 210. This allows the body 210 to be made thinner, thereby increasing the internal space of the body 210. This allows the core located inside the housing 20 to be wound n more times (n≥1, and n is an integer), increasing the energy storage capacity of the single battery cell.

[0048] When the ratio of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220, D3 / D1, is equal to 1, then the thickness D1 of the base plate 220 is equal to the thickness D3 of the cylinder body 210. At this time, the shell 20 has the best strength and the best resistance to deformation, which better meets the requirements of extreme tests such as needle penetration.

[0049] When the ratio of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220, D3 / D1, is equal to 0.44, the thickness D3 of the cylinder body 210 is at its minimum. At this time, the internal space of the cylinder body 210 is at its maximum, allowing the winding core located inside the housing 20 to be wound n more times, thereby increasing the energy storage capacity of the single battery cell.

[0050] When the ratio of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220, D3 / D1, is greater than 1, it is not conducive to the forming of the cylinder body 210 and the base plate 220. On the other hand, it will result in an excessively small internal space for the cylinder body 210 and a large weight for the cylinder body 210, which contradicts the development requirements of lightweight and high energy density of battery packs. When the ratio of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220, D3 / D1, is less than 0.44, it will result in insufficient strength and poor resistance to deformation of the cylinder body 210, making it easy for the cylinder body 210 to be squeezed and deformed, causing damage to the internal electrode assembly 10. In severe cases, it may cause battery combustion and pose a safety hazard.

[0051] In some embodiments, the ratio D3 / D1 of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220 can be 0.44, 0.6, 0.8, 1, or any value between the two, as long as it meets the strength requirements of the shell 20.

[0052] For example, the thickness D1 of the base plate 220 can be set to 0.5 mm, and the thickness D3 of the cylinder body 210 can be set to 0.3 mm. In this case, the ratio D3 / D1 of the thickness D3 of the cylinder body 210 to the thickness D1 of the base plate 220 is 0.6.

[0053] like Figure 4 and Figure 5 As shown, in some embodiments, the weld portion 310 is welded to the base plate 220 to form a weld line 40 on the base plate 220. The width of the weld line 40 is D4, satisfying: 0.15 mm ≤ D4 ≤ 0.25 mm.

[0054] Understandably, the welding equipment performs welding on the side of the base plate 220 away from the welding part 310, thereby forming a weld on the base plate 220. Setting the weld width D4 within the range of 0.15 mm to 0.25 mm ensures the welding strength between the base plate 220 and the welding part 310, guaranteeing welding quality. When the weld width D4 is less than 0.15 mm, the welding process may become unstable, leading to welding defects such as porosity and lack of fusion. When the weld width D4 is greater than 0.25 mm, on the one hand, welding efficiency decreases and welding costs increase; on the other hand, stress integration may cause welding deformation of the base plate 220 and / or the welding part 310, affecting welding quality.

[0055] In some embodiments, the width D4 of the weld line 40 can be set to 0.15 mm, 0.2 mm, 0.25 mm, or any value between the two. This ensures a reliable connection between the base plate 220 and the welded portion 310 without affecting the weld quality.

[0056] Please continue reading. Figure 4 and Figure 5 In some embodiments, the bonding wire 40 includes at least two spaced-apart arc segments. Alternatively, the bonding wire 40 is configured as a ring.

[0057] It is understandable that the connection between the base plate 220 and the welding part 310 can be achieved through multiple intermittent arc-shaped welding lines 40. Alternatively, the connection between the base plate 220 and the welding part 310 can be achieved through a complete circular welding line 40.

[0058] The longer the weld line 40, the more difficult it is to blow carbon dioxide shielding gas. Conversely, a shorter weld line 40 increases the risk of the base plate 220 and the welded section 310 being penetrated, as its head and tail are more easily punctured. Therefore, the length, number, and spacing of the arc segments can be rationally selected.

[0059] In some embodiments, at least two of the arc segments are positioned on the same circumference. Each arc segment corresponds to the same central angle. The angular spacing between any two adjacent arc segments is the same.

[0060] For example, the arc segment is set to four segments, and the four arc segments are centrally symmetrically distributed. This makes the air blowing difficulty of welding between the base plate 220 and the welding part 310 relatively small, and reduces the possible welding defects.

[0061] like Figure 1 and Figure 2 As shown, in some embodiments, the welding structure further includes a sleeve 50. The sleeve 50 is fitted over the outside of the cylinder body 210. The sleeve 50 has an extension 510 bent to the base plate 220. The extension 510 covers the weld line 40.

[0062] Understandably, the sleeve 50 serves two purposes: firstly, it provides protection, preventing the housing 20 from being damaged by collision with external structures; secondly, it provides insulation and corrosion protection to the periphery of the housing 20. Specifically, the extension 510 of the sleeve 50 covers the welding wire 40, thus providing insulation protection for the welding wire 40.

[0063] Because the nickel plating layer on the surface of the base plate 220 is damaged during laser welding between the base plate 220 and the weld 310, the corrosion resistance of the base plate 220 at the weld seam is severely reduced. The extension 510 of the sleeve 50 covers the weld line 40, thereby utilizing the extension 510 to achieve a corrosion-resistant effect.

[0064] The extension 510 is annular. The outer diameter of the extension 510 is the same as the diameter of the base plate 220. A smaller inner diameter of the extension 510 results in a larger area covered by it, leading to better corrosion protection. Conversely, a larger inner diameter results in a smaller area covered by the extension 510. While still providing corrosion protection, this extension uses less material, resulting in lower cost, and avoids covering a large area of ​​the base plate 220, thus preventing interference with subsequent welding processes of the individual cells. Therefore, the inner diameter of the extension 510 can be rationally selected based on actual needs, ensuring that the extension 510 completely covers the weld seam.

[0065] like Figure 2 As shown, in some embodiments, the welded structure further includes an anti-corrosion layer 60. The anti-corrosion layer 60 is attached to the base plate 220 and covers the junction of the base plate 220 and the extension 510.

[0066] It is understandable that using the anti-corrosion layer 60 to cover the connection between the base plate 220 and the extension 510 can prevent air and moisture from entering the area between the base plate 220 and the extension 510 from the connection between the base plate 220 and the extension 510, thus preventing corrosion at the weld and improving the corrosion resistance of the base plate 220.

[0067] The anti-corrosion layer 60 can be annular. The outer diameter of the anti-corrosion layer 60 can be the same as the diameter of the base plate 220. The inner diameter of the anti-corrosion layer 60 is smaller than the inner diameter of the extension 510, so that the anti-corrosion layer 60 can cover the extension 510. The circular hole at the center of the anti-corrosion layer 60 can serve as a clearance hole for welding electrical connection pieces to the central area of ​​the base plate 220, enabling series or parallel connection between multiple individual cells.

[0068] In some embodiments, the anti-corrosion layer 60 is provided with an adhesive layer on the side facing the base plate 220, and the adhesive layer is bonded to the base plate 220 and the extension 510.

[0069] Understandably, the adhesive layer is used to connect the anti-corrosion layer 60 with the base plate 220 and the extension 510, ensuring that the anti-corrosion layer 60 can be reliably bonded to the lower surface of the base plate 220.

[0070] If the adhesive layer can completely cover the side of the anti-corrosion layer 60 facing downwards on the bottom plate 220, then the shape of the adhesive layer is the same as the shape of the anti-corrosion layer 60.

[0071] In some embodiments, the thickness of the anti-corrosion layer 60 is D5. The following condition must be met: 0.02 mm ≤ D5 ≤ 0.2 mm.

[0072] It is understandable that making the anti-corrosion layer 60 thinner can prevent the anti-corrosion layer 60 from causing an increase in the height of a single cell.

[0073] For example, the thickness D5 of the anti-corrosion layer 60 can be set to 0.02 mm, 0.08 mm, 0.15 mm, 0.2 mm, or any value between the two. This application embodiment does not limit the specific value of the anti-corrosion layer 60, as long as it ensures that the anti-corrosion layer 60 can achieve the anti-corrosion effect.

[0074] In some embodiments, the thickness of the adhesive layer is D6. This satisfies the following condition: 0.01 mm ≤ D6 ≤ 0.13 mm.

[0075] It is understandable that making the adhesive layer thinner can prevent the adhesive layer from increasing the height of the individual cells.

[0076] For example, the thickness D6 of the adhesive layer can be set to 0.01 mm, 0.04 mm, 0.08 mm, 0.13 mm, or any value between the two. This application embodiment does not limit the specific value of the adhesive layer, as long as it ensures sufficient adhesion to prevent the adhesive layer and the anti-corrosion layer 60 from detaching from the base plate 220.

[0077] In this embodiment, the thickness D5 of the anti-corrosion layer 60 is preferably set to 0.035 mm, and the thickness D6 of the adhesive layer is set to 0.13 mm.

[0078] In some embodiments, the anti-corrosion layer 60 includes at least one of a PET layer (Polyethylene Terephthalate), a PVC layer (Polyvinyl Chloride), and a TPU layer (Thermoplastic Polyurethane).

[0079] Based on the choice of material for the anti-corrosion layer 60, it can possess good high-temperature resistance while maintaining a low cost. Therefore, the corrosion resistance of a single cell can be significantly improved with only a small increase in cost.

[0080] In some embodiments, the anti-corrosion layer 60 may be a PET layer. Alternatively, the anti-corrosion layer 60 may be a PVC layer. Alternatively, the anti-corrosion layer 60 may be a TPU layer. Alternatively, the anti-corrosion layer 60 may be stacked as two layers, with each layer being a PET layer and a PVC layer. Alternatively, the anti-corrosion layer 60 may be stacked as three layers, with each layer being a PET layer, a PVC layer, and a TPU layer.

[0081] In some embodiments, the adhesive layer can be glue, solid glue, etc. The adhesive layer can be a single-material adhesive or a composite-material adhesive. This application embodiment does not limit the material of the adhesive layer, as long as it ensures sufficient adhesion to prevent the adhesive layer and the anti-corrosion layer 60 from detaching from the base plate 220.

[0082] like Figure 3 As shown, in some embodiments, the height difference between the welded part 310 and the manifold 30 is δ, which satisfies: 0.05 mm ≤ δ ≤ 0.15 mm.

[0083] Understandably, since the welding part 310 needs to protrude towards the base plate 220, a height difference will be formed between the welding part 310 and the busbar 30. Based on setting the height difference δ between the welding part 310 and the busbar 30 within the range of 0.05 mm to 0.15 mm, after the central region of the busbar 30 is welded to the center of the electrode assembly 10, the deformation of the busbar edge will not cause a gap to form between the welding part 310 and the base plate 220, thus preventing a weak weld between the welding part 310 and the base plate 220.

[0084] Specifically, when the height difference δ between the welding part 310 and the busbar 30 is less than 0.05 mm, deformation of the busbar edge may cause a gap to form between the welding part 310 and the base plate 220, resulting in a weak weld and an unreliable connection between the welding part 310 and the base plate 220. When the height difference δ between the welding part 310 and the busbar 30 is greater than 0.15 mm, the height of the individual battery cell will increase significantly, which is not conducive to the installation of the individual battery cell.

[0085] In some embodiments, the height difference δ between the welded part 310 and the busbar 30 can be set to 0.05 mm, 0.1 mm, 0.15 mm, or any value between the two, to ensure that the deformation of the busbar edge will not cause a gap to form between the welded part 310 and the base plate 220.

[0086] On the other hand, embodiments of this application also provide a single-cell battery. This single-cell battery includes the welding structure as described in the foregoing embodiments.

[0087] In this embodiment, a welding portion 310 protruding towards the base plate 220 is provided on the periphery of the busbar 30. This welding portion 310 is used to weld the busbar 30 to the base plate 220, thereby positioning the welding area between the busbar 30 and the base plate 220 at the edge of the base plate 220. This avoids the welding position between the base plate 220 and the electrical connector, ensuring a sufficient welding area between the base plate 220 and the electrical connector. The busbar 30 is welded to the electrode assembly 10 at its center. Welding the center of the busbar 30 to the electrode assembly 10 may cause deformation in the edge area of ​​the busbar 30. By making the welding portion 310 protrude towards the base plate 220, the shape of this protrusion can mitigate the deformation of the welding portion 310, preventing gaps between the welding portion 310 and the base plate 220 and thus preventing incomplete welds.

[0088] In another aspect, embodiments of this application also provide a battery pack. The battery pack includes individual battery cells as described in the foregoing embodiments.

[0089] In this embodiment, a welding portion 310 protruding towards the base plate 220 is provided on the periphery of the busbar 30. This welding portion 310 is used to weld the busbar 30 to the base plate 220, thereby positioning the welding area between the busbar 30 and the base plate 220 at the edge of the base plate 220. This avoids the welding position between the base plate 220 and the electrical connector, ensuring a sufficient welding area between the base plate 220 and the electrical connector. The busbar 30 is welded to the electrode assembly 10 at its center. Welding the center of the busbar 30 to the electrode assembly 10 may cause deformation in the edge area of ​​the busbar 30. By making the welding portion 310 protrude towards the base plate 220, the shape of this protrusion can mitigate the deformation of the welding portion 310, preventing gaps between the welding portion 310 and the base plate 220 and thus preventing incomplete welds.

[0090] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A welded structure, characterized by, The application relates to a welding structure of an electrode assembly. The welding structure comprises: an electrode assembly; a shell comprising a barrel and a bottom plate, the electrode assembly being arranged in the barrel, and the bottom plate being arranged at a distance from a first electrode of the electrode assembly; 2. The welded structure of claim 1, wherein a busbar between the bottom plate and the first electrode of the electrode assembly, the busbar being provided with a welding portion protruding towards the bottom plate, wherein the busbar is welded to the first electrode of the electrode assembly, and the welding portion is welded to the bottom plate.

3. The welded structure of claim 1, wherein The thickness of the bottom plate is D1, and the thickness of the welding portion is D2, and 0 < D1 / D2 < 3 is satisfied.

4. The welded structure according to any one of claims 1 to 3, characterized in that, The thickness of the bottom plate is D1, and the thickness of the barrel is D3, and 0.44 < D3 / D1 < 1 is satisfied.

5. The welded structure of claim 4, wherein The welding portion is welded to the bottom plate to form a welding line on the bottom plate, the width of the welding line is D4, and 0.15 mm < D4 < 0.25 mm is satisfied.

6. The welded structure of claim 4, wherein The welding line comprises at least two circular arc segments arranged at a distance, or the welding line is arranged in a circular ring shape. The welding structure further comprises:

7. The welded structure of claim 6, wherein a sleeve sleeved on the outside of the barrel, the sleeve being provided with an extension bent to the bottom plate, and the extension covering the welding line. The welding structure further comprises:

8. The welded structure of claim 7, wherein an anti-corrosion layer connected to the bottom plate and covering the joint between the bottom plate and the extension.

9. The welded structure according to any one of claims 1 to 3, characterized in that, The anti-corrosion layer is provided with a glue layer on the side facing the bottom plate, and the glue layer is bonded to the bottom plate and the extension.

10. A single cell characterized by, The height difference between the welding portion and the busbar is delta, and 0.05 mm < delta < 0.15 mm is satisfied.

11. A battery pack, characterized by, The application relates to a welding structure of an electrode assembly. The application relates to a welding structure of an electrode assembly. The application relates to a welding structure of an electrode assembly.

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