Current collector, cylindrical battery and assembly method thereof

Abstract

The present application provides a current collector, a columnar battery and an assembly method thereof, wherein the current collector comprises a shell welding area and a wing extending from at least one end of the shell welding area, the wing being used for welding with the full pole ear of the winding core, the wing having a first side edge, and the first side edge and the connection with the shell welding area forming an angle, the formation of the angle enabling elastic deformation between the wing and the shell welding area. In the present application, after the wing is welded with the full pole ear of the winding core, when the shell welding area is welded with the bottom wall of the shell, elastic deformation can occur between the shell welding area and the wing to release the generated stress, avoiding direct pulling of the welding position between the wing and the full pole ear, in addition, when the assembled columnar battery causes the winding core to jump due to the vibration of loading, etc. and drives the wing to jump together, elastic deformation can also occur between the shell welding area and the wing to release the impact stress, avoiding the risk of open circuit at the welding position between the shell welding area and the bottom wall of the shell, thereby improving the anti-seismic performance of the columnar battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a current collector, a cylindrical battery and an assembly method thereof. Background Art

[0002] At present, lithium-ion / sodium-ion cylindrical batteries have gradually become mainstream products in the new energy industry due to their high energy density, good capacity consistency, and ability to support high-rate charge and discharge. More and more manufacturers continue to pursue compactness optimization of cylindrical battery structures to improve energy density. However, cylindrical batteries currently have the following problems on the current collector:

[0003] (1) The current collectors commonly used in cylindrical batteries are more complex in design and use more metal materials, resulting in higher battery production costs.

[0004] (2) For the newly emerging current collector with a minimalist rectangular strip structure, when it is first laser welded to the full-ear tab of the winding core and then the middle part of the current collector is welded to the bottom wall of the shell by resistance welding, the full-ear tab welding position will be pulled. In addition, due to the rigid connection between the full-ear tab and the current collector and the current collector and the bottom of the shell, the winding core will directly impact the welding position during the loading vibration (the larger winding core inside will jump), which is easy to fall off, resulting in the risk of open circuit failure of the cylindrical battery. Summary of the invention

[0005] The purpose of the present application is to provide a current collector and a cylindrical battery, which can solve at least one technical problem mentioned in the background technology.

[0006] In order to achieve the above-mentioned purpose, the present application provides a current collector, including a shell welding area and a wing extending from at least one end of the shell welding area, the wing being used to be welded to the full pole ear of the winding core, the wing having a first side edge, and the first side edge forming an angle with the connection between the shell welding area, the formation of the angle enables the wing and the shell welding area to be elastically deformed.

[0007] Optionally, the shell welding area includes an adjacent second side and a third side, the wing extends from the second side, the first side of the wing is connected to the third side, and the connection between the first side and the third side forms the angle, which is an obtuse angle.

[0008] Optionally, the angle is between 110° and 160°.

[0009] Optionally, the shell welding area includes a second side edge, the wing portion extends from the second side edge, one end of the second side edge exceeds the starting position of the wing portion and forms the angle at the connection with the first side edge of the wing portion, and the angle is an acute angle.

[0010] Optionally, the angle is between 30° and 70°.

[0011] Optionally, at least one welding track is formed on the wing portion, and the welding track is configured to conduct all the tabs of each layer from the inner circle to the outer circle of the winding core.

[0012] Optionally, the wings extend from both opposite ends of the shell welding area.

[0013] Optionally, the wing portion extends out in a strip shape, and / or the current collecting piece is in a bent strip shape as a whole.

[0014] In order to achieve the above-mentioned purpose, the present application also provides a cylindrical battery, including a winding core, a shell and a current collecting sheet as described above, wherein the winding core is placed in the shell, the current collecting sheet is arranged between the winding core and the bottom wall of the shell, the shell welding area is arranged corresponding to the through hole of the winding core and welded to the bottom wall of the shell, the wing is welded to the full pole ear of the winding core, and when the wing vibrates with the winding core, elastic deformation is generated between the wing and the shell welding area to release stress.

[0015] The present application also provides a method for assembling the cylindrical battery as described above, comprising:

[0016] Welding the wing of the current collector to the full tab of the winding core so that the shell welding area of ​​the current collector corresponds to the through hole of the winding core;

[0017] Put the winding core into the shell so that the current collecting sheet faces the bottom wall of the shell;

[0018] The shell welding area of ​​the current collecting sheet is welded to the bottom wall of the shell by utilizing the through hole of the winding core.

[0019] In the present application, the current collector is a simple sheet structure. On the basis of ensuring less material and low cost, the angle between the shell welding area and the wing is set so that the shell welding area and the wing can be elastically deformed. After the wing is welded to the full pole ear of the winding core, when the shell welding area is welded to the bottom wall of the shell, elastic deformation can occur between the shell welding area and the wing to release the generated stress and avoid directly pulling the welding position between the wing and the full pole ear. In addition, when the cylindrical battery after assembly causes the winding core to jump due to loading vibration and drives the wing to jump together, elastic deformation can also occur between the shell welding area and the wing to release the impact stress and avoid the risk of open circuit at the welding position of the shell welding area and the bottom wall of the shell, thereby improving the seismic performance of the columnar battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the current collecting sheet of the embodiment of the present application.

[0021] Figure 2It is a schematic diagram of the top view of the structure after the current collecting sheet and the winding core are assembled in the embodiment of the present application.

[0022] Figure 3 It is a schematic diagram of the exploded structure of the cylindrical battery of the embodiment of the present application.

[0023] Figures 4 to 15 They are respectively schematic diagrams of the structures of the current collecting sheets according to different embodiments of the present application.

[0024] Fig.16 It is a flow chart of the assembly method of the cylindrical battery of the embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0026] See also Figures 1 to 15 , the embodiment of the present application discloses a current collector 1. The current collector 1 is used for a cylindrical battery, and the cylindrical battery also includes a winding core 2 and a shell 3. When the assembly is completed, the winding core 2 is sleeved in the shell 3, and the current collector 1 is located between the winding core 2 and the bottom wall 30 of the shell 3, and is welded to the full pole ear of the winding core 2 and the bottom wall 30 of the shell 3 respectively. The current collector 1 includes a shell welding area 11 for welding to the bottom wall 30 of the shell 3 and a wing 12 extending from at least one end of the shell welding area 11, and the wing 12 is used to weld to the full pole ear of the winding core 2. The wing 12 has a first side 121, and the connection between the first side 121 and the shell welding area 11 forms an angle a, and the formation of the angle a allows the wing 12 and the shell welding area 11 to be elastically deformed.

[0027] It should be explained that the formation of angle a allows elastic deformation between the wing 12 and the shell welding area 11, which means that the wing 12 extends straight from the shell welding area 11, and the connection between the shell welding area 11 and the wing 12 has no angle a (180 degrees, for example, the collector is a rectangular strip structure) or the angle a is 90 degrees, so that the shell welding area 11 and the wing 12 are rigidly connected. By forming angle a, the shell welding area 11 and the wing 12 can be elastically deformed and become an elastic connection. In this way, when the shell welding area 11 and the wing 12 are pulled or driven up and down, elastic deformation can occur to release stress. For example, after the wing 12 is first welded to the full pole ear of the core 2, and then the shell welding area 11 is welded to the bottom wall 30 of the shell 3, elastic deformation can occur between the wing 12 and the shell welding area 11 to release the stress generated thereby; when the cylindrical battery causes the core 2 to jump due to loading vibration, etc. and drives the wing 12 to jump together, elastic deformation can also occur between the wing 12 and the shell welding area 11 to release the impact stress.

[0028] In the present application, the current collector 1 is a simple sheet structure. On the basis of ensuring less material and low cost, the angle a between the shell welding area 11 and the wing 12 is set so that the shell welding area 11 and the wing 12 can be elastically deformed. After the wing 12 is welded to the full pole ear of the winding core 2, when the shell welding area 11 is welded to the bottom wall 30 of the shell 3, elastic deformation can occur between the shell welding area 11 and the wing 12 to release the generated stress and avoid directly pulling the welding position of the wing 12 and the full pole ear. In addition, when the cylindrical battery after assembly causes the winding core 2 to jump and drives the wing 12 to jump together due to loading vibration, elastic deformation can also occur between the shell welding area 11 and the wing 12 to release the impact stress, avoiding the risk of open circuit at the welding position of the shell welding area 11 and the bottom wall 30 of the shell 3, thereby improving the seismic performance of the cylindrical battery.

[0029] Optionally, the current collecting sheet 1 is made of copper, nickel, copper-nickel composite strip or aluminum. Of course, the current collecting sheet 1 can also be made of other materials.

[0030] exist Figures 1 to 14 In the example, the shell welding area 11 includes a second side 111 and a third side 112 adjacent to each other, the wing 12 extends from the second side 111, the first side 121 of the wing 12 is connected to the third side 112, and the connection between the first side 121 and the third side 112 forms an angle a, which is an obtuse angle. Preferably, the angle a is between 110° and 160°.

[0031] See also Figures 1 to 3Specifically, the shell welding area 11 is configured to be assembled corresponding to the through hole 21 of the winding core 2. After the current collecting sheet 1 and the winding core 2 are assembled, the shell welding area 11 at least partially extends outward beyond the through hole 21 of the winding core 2 to facilitate welding. Optionally, the shell welding area 11 extends outward beyond the through hole 21 of the winding core 2 as a whole, that is, the projection of the through hole 21 of the winding core 2 on the current collecting sheet 1 is located on the inner side of the outer periphery of the shell welding area 11.

[0032] exist Figure 1 In the example, the shell welding area 11 is roughly rectangular, and the width L of the shell welding area 11 is greater than the diameter of the through hole 21 of the winding core 2. After the collector 1 and the winding core 2 are assembled, both ends of the shell welding area 11 extend outward beyond the through hole 21 of the winding core 2.

[0033] exist Figure 1 In the example, the shell welding area 11 is generally rectangular as a whole, but it is not limited to this.

[0034] exist Figure 1 In the example, at least one welding track 122 is formed on the wing 12, and the welding track 122 is configured to conduct all the tabs of each layer from the inner circle to the outer circle of the winding core 2. The welding track 122 can have a straight or spiral appearance, etc., which is not limited.

[0035] exist Figure 1 In the example, wings 12 extend from opposite ends of the shell welding area 11, and the wings 12 at both ends can be welded to the full tabs on both sides of the through hole 21 of the winding core 2. It can be understood that the present application is not limited to this.

[0036] Specifically, in this example, the two wings 12 of the current collecting sheet 1 located at both ends of the shell welding area 11 are bent toward the same side of the shell welding area 11. Of course, when the wings 12 are extended at both ends of the shell welding area 11, it is not limited to this. For example, Figure 4 In the shown current collecting sheet 1 , two wing portions 12 located at two ends of the shell welding area 11 are bent toward different sides of the shell welding area 11 .

[0037] Specifically, the wing portions 12 at opposite ends of the shell welding area 11 are symmetrically arranged or asymmetrically arranged.

[0038] exist Figure 1 In the example, the wing 12 extends in a strip shape, that is, the wing 12 extends a longer length relative to its overall width. Specifically, the wing 12 can be a relatively regular strip structure with a uniform width. Of course, the wing 12 is not limited to having a uniform width. More specifically, the width of the wing 12 is less than the radius of the core 2.

[0039] exist Figure 1In the example, the current collecting sheet 1 is in the shape of a strip with a bend as a whole. Specifically, in this example, the current collecting sheet 1 has two bends, and the two bends define the wing portions 12 at both ends and the shell welding area 11 between the two wing portions 12, and the bends form an angle a. Of course, when the current collecting sheet 1 is in the shape of a strip with a bend as a whole, it may also include only one bend, that is, a wing portion 12 that forms an angle a with the shell welding area 11.

[0040] Specifically, in this example, the current collecting sheet 1 may have a uniform width as a whole, that is, the widths of the shell welding area 11 and the wing portion 12 are substantially the same. More specifically, the overall width of the current collecting sheet 1 is smaller than the radius of the winding core 2 .

[0041] Figure 5 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Figure 1 The main difference between the current collector 1 shown in FIG. 1 and FIG. 2 is that only one end of the shell welding area 11 extends out of the wing portion 12 .

[0042] Figure 6 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Figure 5 The main difference between the current collector 1 shown in FIG. 1 and FIG. 2 is that the shape of the wing 12 is different. In this example, the end of the wing 12 has an arc structure. Of course, the wing 12 can also be in other shapes, such as Figure 7 In the example of FIG. 1 , wings 12 of different shapes are shown.

[0043] Figure 8 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Figure 5 The main difference between the current collector 1 shown in FIG. 1 and FIG. 2 is that the shape of the shell welding area 11 is different. In this example, the end of the shell welding area 11 away from the wing 12 has an arc structure. Of course, the shell welding area 11 can also have other shapes.

[0044] Fig. 9 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Figure 5 The main difference between the collector 1 shown in FIG. 1 and FIG. 2 is that the shape of the shell welding area 11 is different. In this example, the shell welding area 11 is roughly circular. Of course, the shell welding area 11 can also be other shapes. In this example, the first side 121 is a straight line, the third side 112 is an arc, and the angle a is the angle a formed between the tangents of the first side 121 and the third side 112 at the connection point. Fig.10 In the example given, the shell welding area 11 is also roughly circular, the first side 121 is a straight line, the third side 112 is an arc, and the angle a is the angle a formed between the tangents of the first side 121 and the third side 112 at the connection point.

[0045] Fig.11A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Figure 5 The main differences of the collector sheet 1 shown in are: Figure 5 The shell welding area 11 of the middle current collecting sheet 1 is rectangular, and the second side 111 extending out of the wing portion 12 is a side of the rectangle. Fig.11 The shell welding area 11 of the middle current collecting plate 1 is in the shape of a rectangle with one corner cut off, and the second side edge 111 of the extended wing portion 12 is the side edge formed by cutting the corner of the shell welding area 11 .

[0046] Fig.12 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Fig.11 The main difference between the current collecting sheet 1 shown in FIG. 1 and FIG. 2 is that the shape of the wing 12 is different. In this example, the end of the wing 12 has an arc structure.

[0047] Fig.13 A different example of the current collecting piece 1 is given. The current collecting piece 1 in this example is Fig.11 The main difference of the current collecting sheet 1 shown in FIG. 1 is that the end of the shell welding area 11 away from the wing portion 12 has an arc structure.

[0048] Fig.14 A different example of a current collecting piece 1 is given. In this example, the shell welding area 11 of the current collecting piece 1 is substantially trapezoidal, the second side 111 extending out of the wing portion 12 is the narrower bottom of the trapezoid, and the third side 112 is the height of the trapezoid.

[0049] The third side 112 in the above examples is substantially in a straight line or an arc shape, but is not limited thereto.

[0050] Fig.15 A different example of the current collector 1 is given. In this example, the shell welding area 11 includes a second side 111, the wing 12 extends from the second side 111, one end of the second side 111 exceeds the starting position of the wing 12 (i.e., the connection with the second side 111) and forms an angle a with the connection with the first side 121 of the wing 12, and the angle a is an acute angle. The second side 111 in this example is a straight line, but it is not limited to this, and can also be other shapes, such as an arc shape.

[0051] Optionally, the angle a is between 30° and 70°.

[0052] It should be explained that in the present application, the shell welding area 11 and the wing 12 are not limited to the shapes in the above examples, and the shell welding area 11 and the wing 12 can be designed into various shapes as needed. In the above examples, the first side 121 is basically straight, of course, the first side 121 is not limited to this, and can also be a curve or other regular or irregular shapes, as long as the connection between it and the shell welding area 11 can form an angle, and the angle can allow the shell welding area 11 and the wing 12 to be elastically deformed.

[0053] See also Figures 1 to 3 The present application also discloses a cylindrical battery, comprising a winding core 2, a shell 3 and the current collecting sheet 1 as described above, wherein the winding core 2 is placed in the shell 3, the current collecting sheet 1 is arranged between the winding core 2 and the bottom wall 30 of the shell 3, the shell welding area 11 is arranged corresponding to the through hole 21 of the winding core 2 and welded to the bottom wall 30 of the shell 3, the wing 12 is welded to the full pole ear of the winding core 2, and when the wing 12 vibrates with the winding core 2, elastic deformation occurs between the wing 12 and the shell welding area 11 to release stress.

[0054] In the present application, the current collector 1 is a simple sheet structure. On the basis of ensuring less material and low cost, the angle a between the shell welding area 11 and the wing 12 is set so that the shell welding area 11 and the wing 12 can be elastically deformed. Therefore, when the cylindrical battery after assembly causes the winding core 2 to jump due to loading vibration and drives the wing 12 to jump together, elastic deformation can occur between the shell welding area 11 and the wing 12 to release the impact stress, thereby avoiding the risk of open circuit at the welding position of the shell welding area 11 and the bottom wall 30 of the shell 3, and improving the seismic performance of the cylindrical battery.

[0055] Specifically, the full-tab welding of the wing portion 12 and the winding core 2 is performed by laser welding.

[0056] Specifically, the shell welding area 11 is welded to the bottom wall 30 of the shell 3 by resistance welding. Of course, it is not limited to this, for example, laser welding or penetration welding can also be used.

[0057] Specifically, the shell welding area 11 at least partially extends outwardly beyond the through hole 21 of the winding core 2 to facilitate welding.

[0058] exist Figure 1 In the example shown, the shell welding area 11 is roughly rectangular, and the width L of the shell welding area 11 is larger than the diameter of the through hole 21 of the winding core 2. After the current collecting sheet 1 and the winding core 2 are assembled, both ends of the shell welding area 11 extend outward beyond the through hole 21 of the winding core 2.

[0059] Please combine Figures 1 to 3 as well as Fig.16 The present application also discloses a method for assembling the cylindrical battery as described above, comprising:

[0060] S1, welding the wing 12 of the current collector 1 to the full tab of the winding core 2, so that the shell welding area 11 of the current collector 1 corresponds to the through hole 21 of the winding core 2;

[0061] S2, placing the winding core 2 into the housing 3, with the current collecting sheet 1 facing the bottom wall 30 of the housing 3;

[0062] S3 . Using the through hole 21 of the winding core 2 , the shell welding area 11 of the current collecting sheet 1 is welded to the bottom wall 30 of the shell 3 .

[0063] After the wing 12 is welded to the entire tab of the winding core 2, when the shell welding area 11 is welded to the bottom wall 30 of the shell 3, elastic deformation can occur between the wing 12 and the shell welding area 11 to release the stress generated thereby and avoid direct pulling of the welding position between the wing 12 and the entire tab.

[0064] Specifically, before step S1 , the assembly method may further include a pre-processing step. In the pre-processing step, the entire tab of the winding core 2 may be flattened.

[0065] The above disclosure is only a preferred example of the present application, and its role is to facilitate the technical personnel in this field to understand and implement it. Of course, it cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the scope of the patent application of the present application still fall within the scope covered by the present application.

Claims

1. A current collecting sheet, characterized in that: The invention comprises a shell welding area and a wing extending from at least one end of the shell welding area, wherein the wing is used for welding with the full tab of the winding core, and the wing has a first side edge, and the first side edge forms an angle with the connection of the shell welding area, and the formation of the angle enables elastic deformation between the wing and the shell welding area; The wings extend from opposite ends of the shell welding area; The wing portion extends out in a strip shape, and the current collecting piece as a whole is in a bent strip shape; The angle is between 110° and 160°.

2. The current collecting sheet according to claim 1, characterized in that: The shell welding area includes a second side and a third side adjacent to each other, the wing extends from the second side, the first side of the wing is connected to the third side, and the connection between the first side and the third side forms the angle, which is an obtuse angle.

3. The current collecting sheet according to claim 1, characterized in that: At least one welding track is formed on the wing portion, and the welding track is configured to conduct all the tabs of each layer from the inner circle to the outer circle of the winding core.

4. A cylindrical battery, characterized in that: It includes a winding core, a shell and a current collecting sheet as described in any one of claims 1 to 3, the winding core is placed in the shell, the current collecting sheet is arranged between the winding core and the bottom wall of the shell, the shell welding area is arranged corresponding to the through hole of the winding core and welded to the bottom wall of the shell, the wing is welded to the full pole ear of the winding core, and when the wing vibrates with the winding core, elastic deformation is generated between the wing and the shell welding area to release stress.

5. A method for assembling a cylindrical battery as claimed in claim 4, characterized in that: include: Welding the wing of the current collector to the full tab of the winding core so that the shell welding area of ​​the current collector corresponds to the through hole of the winding core; Put the winding core into the shell so that the current collecting sheet faces the bottom wall of the shell; The shell welding area of ​​the current collecting sheet is welded to the bottom wall of the shell by utilizing the through hole of the winding core.

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