Cover plate assembly of cylindrical battery and cylindrical battery

Abstract

The utility model provides a cylindrical battery cover plate assembly and a cylindrical battery, the cylindrical battery comprises the cover plate assembly, a shell, a battery cell and a sealing piece, the cover plate assembly comprises a cover plate and a current collecting disc, the cover plate is provided with a pole and at least one through hole, the current collecting disc is located at one end of the cover plate, and the through hole penetrates from a first end face to a second end face of the cover plate; at least part of the orthographic projection of the current collecting disc on the second end face coincides with the through hole, the ratio of the area of the through hole on the second end face to the area of the second end face is A, and A is larger than or equal to 0.03 and smaller than or equal to 0.1. The battery cell is located in a containing cavity defined by the shell and the cover plate, the battery cell comprises a battery cell body and a first tab, the first tab is arranged at the end, close to the cover plate, of the battery cell body, the current collecting disc is located between the cover plate and the battery cell, and the current collecting disc is welded to the first tab; the orthographic projections of the collector plate and the first tab welded on the second end face of the cover plate at least partially coincide with the through hole in the cover plate, and the through hole is sealed by the sealing piece. The cylindrical battery is not easy to generate electrochemical corrosion.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate assembly for a cylindrical battery and a cylindrical battery. Background Technology

[0002] A typical existing cylindrical battery welding process involves first welding the tabs to the current collector, then assembling the cover plate onto the casing, performing through-welding on the current collector to the cover plate or the terminals on the cover plate, and finally welding the cover plate to the casing. During the through-welding process, the current collector and casing melt. Since the current collector and casing are typically made of dissimilar metals, the molten dissimilar metals form a new alloy, causing electrochemical corrosion and affecting the lifespan and performance of the cylindrical battery. Therefore, how to avoid the adverse effects of this phenomenon on the lifespan and performance of cylindrical batteries is a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0003] To address the aforementioned technical problems, this application provides a cover plate assembly for a cylindrical battery, comprising a cover plate and a current collector. The cover plate has a terminal post and at least one through hole. The current collector is located at one end of the cover plate. The cover plate has a first end face relatively far from the current collector and a second end face relatively close to the current collector. The through hole extends from the first end face to the second end face. The orthographic projection of the current collector on the second end face at least partially coincides with the through hole. The ratio of the area of ​​the through hole on the second end face to the area of ​​the second end face is A, and the range of A is: 0.03 ≤ A ≤ 0.1.

[0004] This application also provides a cylindrical battery, including the above-mentioned cover plate assembly, and further including a housing, a cell, and a sealing member. The housing has an opening, and the cover plate is welded to the housing to close the opening. The cell is located within a receiving cavity formed by the housing and the cover plate. The cell includes a cell body and a first electrode tab. The first electrode tab is disposed at one end of the cell body near the cover plate. The current collector is located between the cover plate and the cell. The current collector is welded to the first electrode tab. The orthographic projection of the current collector and the first electrode tab on the second end face of the cover plate at least partially coincides with the through hole on the cover plate. The sealing member is welded to the cover plate to close the through hole.

[0005] The cylindrical battery provided in this application has through holes in the cover plate, so that the solder marks of the current collector and the first electrode tab located at one end of the cell body near the cover plate at least partially overlap on the orthogonal projection of the cover plate near the cell. This design allows the cylindrical battery to be welded in the following process sequence: first, weld the cover plate and the current collector, then weld the cover plate and the casing, and finally weld the current collector and the first electrode tab through the through holes in the cover plate. In this way, the problem of electrochemical corrosion caused by the melting of the dissimilar metal current collector and casing during the process of penetrating the cover plate and the current collector is avoided, which affects the life and performance of the cylindrical battery.

[0006] Furthermore, by controlling the ratio A of the area of ​​the through hole on the second end face of the cover plate near the cell to the area of ​​the second end face to be within the range of 0.03-0.1, the strength of the cover plate is ensured, the operation is easy when welding the first tab and current collector, and the problem of damage to the cylindrical battery separator caused by the inability to quickly release welding heat during the welding process of the tab and current collector is avoided. Attached Figure Description

[0007] Figure 1 A perspective view of one embodiment of the cover plate assembly for the cylindrical battery provided in this application;

[0008] Figure 2 for Figure 1 Another perspective view;

[0009] Figure 3 A perspective view of one embodiment of the cylindrical battery provided in this application;

[0010] Figure 4 for Figure 2 A partial sectional view;

[0011] Figure 5 for Figure 4 A magnified view of a portion of the image.

[0012] The annotations in the attached figures are explained as follows:

[0013] 1. Housing, 1a. Annular boss, 2. Cover plate, 21. First end face, 22. Second end face, 21a. Second annular groove, 22a. First annular groove, 3. Battery cell, 41. First current collector, 42. Second current collector, 5. First pole post, 6. Seal. Detailed Implementation

[0014] This application provides a cover plate assembly for a cylindrical battery and the cylindrical battery itself. To enable those skilled in the art to better understand the technical solution of this application, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0015] like Figure 1 and Figure 2As shown, the cover plate assembly of the cylindrical battery provided in this application includes a cover plate 2 and a current collector. The cover plate 2 has terminals and at least one through hole X. Exemplarily, in the illustrated embodiment, the cover plate 2 has two through holes X. Alternatively, only one through hole X or more through holes X may be provided. The current collector is located at one end of the cover plate 2. The cover plate 2 has a first end face 21 relatively far from the current collector and a second end face 22 relatively close to the current collector. The through hole X extends from the first end face 21 to the second end face 22. The orthographic projection of the current collector onto the second end face 22 at least partially coincides with the through hole X. The ratio of the area of ​​the through hole X on the second end face 22 to the area of ​​the second end face 22 is A, where A ranges from 0.03 ≤ A ≤ 0.1. Exemplarily, the value of A can specifically be 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1. Specifically, when the second end face 22 is provided with a groove or a protrusion, the area of ​​the second end face 22 refers to the area of ​​the remaining planar area excluding the area occupied by the groove or protrusion. For example, in the illustrated embodiment, the two through holes X have the same area of ​​28.26 mm on the second end face 22. 2 The area of ​​cover plate 2 is 1661.06 mm². 2 .

[0016] like Figure 3 and Figure 4 As shown, the cylindrical battery provided in this application includes at least a casing 1, a cell 3, the aforementioned cover assembly, and a closure (not shown in the figure).

[0017] The housing 1 has an opening, and the cover plate 2 is welded to the housing 1 and closes the opening. The housing 1 and the cover plate 2 together form a receiving cavity. Specifically, the housing 1 is generally cylindrical, the opening is located at one axial end of the housing 1, and the cover plate 2 is generally disc-shaped.

[0018] The battery cell 3 is located within the cavity formed by the housing 1 and the cover plate 2. The battery cell 3 includes at least a cell body and a first electrode tab. The first electrode tab is located at the end of the cell body near the cover plate 2. Specifically, the cell body is a cylindrical structure formed by winding a laminated structure. One axial end of the cylindrical structure is close to the cover plate 2, and the other axial end is away from the cover plate 2. The laminated structure includes alternating positive and negative electrode plates, and a separator is provided between adjacent positive and negative electrode plates.

[0019] The current collector is located between the cover plate 2 and the battery cell 3, and is welded to the first electrode tab. The orthographic projection of the solder marks of the current collector and the first electrode tab on the second end face 22 of the cover plate 2 at least partially coincides with the through hole X.

[0020] The sealing component connects to the cover plate 2 and seals the through hole X. Specifically, the sealing component seals the through hole X after the first electrode tab and the current collector are welded. Although the sealing component seals the through hole X on the cover plate 2 when the cylindrical battery leaves the factory, it can be determined whether the through hole X was ever made on the cover plate 2 by checking whether there is a seam in the area corresponding to the weld marks of the first electrode tab and the current collector. Specifically, the sealing component can be a metal part, which can be welded to the cover plate 2, or it can be a heat-fused polymer plastic part.

[0021] Because the cylindrical battery has a through hole X on the cover plate 2, the solder marks of the current collector and the first electrode tab located at the end of the cell body near the cover plate 2 at least partially overlap on the orthogonal projection of the cover plate 2 near the second end face 22 of the cell 3. This design allows the cylindrical battery to be assembled in the following process sequence: first, the current collector is welded to the cover plate 2 by resistance welding; then, the cell 3 is placed inside the housing 1; then, the cover plate 2 is welded to the housing 1; then, the current collector is welded to the electrode tab through the through hole X; and finally, the through hole X is sealed with a sealing component.

[0022] First, weld the cover plate 2 to the current collector, then weld the cover plate 2 to the shell 1, and finally weld the current collector to the first tab through the through hole X on the cover plate 2. In this way, the problem of electrochemical corrosion caused by the melting of the dissimilar metal current collector and shell 1 during the process of penetrating the cover plate 2 and the current collector is avoided, which affects the life and performance of the cylindrical battery.

[0023] The current collector and the first tab are welded through the through-hole X. During welding, the welding heat is released through the through-hole X. If the area of ​​the through-hole X is too small, the welding operation is difficult, and the welding heat cannot be released quickly, which can damage the cylindrical battery separator. Therefore, the ratio A of the area of ​​the through-hole X on the second end face 22 of the cover plate 2 near the cell 3 to the area of ​​the second end face 22 cannot be too small. If the area of ​​the through-hole X is too large, it will affect the strength of the cover plate 2. Therefore, the ratio A of the area of ​​the through-hole X on the second end face 22 of the cover plate 2 near the cell 3 to the area of ​​the second end face 22 cannot be too large. By controlling the ratio A of the area of ​​the through-hole X on the second end face 22 of the cover plate 2 near the cell 3 to the area of ​​the second end face 22 to the second end face 22 within the range of 0.03-0.1, the strength of the cover plate 2 is ensured, the welding of the first tab and the current collector is easy, and the problem of damage to the cylindrical battery separator due to the inability to release welding heat quickly during the welding process is avoided.

[0024] In some embodiments, the solder marks of the current collector and the first tab on the second end face 22 are projected entirely within the area of ​​the through hole X. Thus, with the same area of ​​the through hole X, welding the current collector and the first tab is easier, and the heat release path is relatively short, making it easier to release heat from the through hole X.

[0025] In some embodiments, the first electrode includes a positive electrode and a negative electrode. That is, both the positive and negative electrodes are located at the end of the cell body near the cover plate 2, so that the solder joints of the first electrode and the current collector include both the positive electrode and the current collector solder joints. In this case, both the positive electrode and the current collector need to be soldered through the through-hole X, and the negative electrode and the current collector also need to be soldered through the through-hole X. Therefore, the area of ​​the through-hole X needs to be appropriately large. Thus, the range of the ratio A of the area of ​​the through-hole X on the second end face 22 and the area of ​​the second end face 22 can be further narrowed to: 0.05 ≤ A ≤ 0.1. For example, the value of A can be 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1.

[0026] In some embodiments, when the first tab includes a positive tab and a negative tab, the current collector includes a first current collector 41 and a second current collector 42. One side of the first current collector 41 and one side of the second current collector 42 are welded to the positive tab, and the other side is welded to the negative tab, such that the solder joints of the first tab and the current collector include the solder joints of the first current collector 41 and the positive or negative tab, and the solder joints of the second current collector 42 and the positive or negative tab. The other side of the first current collector 41 and the other side of the second current collector 42 are welded to the first electrode post 5, and the other side is welded to the cover plate 2, such that the electrode post and the cover plate 2 are two electrodes of different polarities in the cylindrical battery. In this case, since the cover plate 2 serves as an electrode of the cylindrical battery, its current-carrying performance must be considered. The cover plate 2 needs to be welded to the sealing component to close the through-hole X. Therefore, if the area of ​​the through-hole X is too large, the welding area between the cover plate 2 and the sealing component will be large, causing severe heat generation on the cover plate 2 during current flow, thus affecting its current-carrying performance. Therefore, the area of ​​the through-hole X needs to be appropriately small. Thus, the ratio A of the area on the second end face 22 of the through-hole X to the area on the second end face 22 can be further narrowed to: 0.06 ≤ A ≤ 0.09. For example, the value of A can be 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, or 0.09.

[0027] In some embodiments, when the first electrode includes a positive electrode and a negative electrode, the cover plate 2 is provided with two through holes X. On the second end face 22 of the cover plate 2, the shortest distance B between the two through holes X is in the range of 8mm ≤ B ≤ 35mm. For example, the value of B can be 8mm, 10mm, 15mm, 20mm, 25mm, 30mm, or 35mm. With this design, the positive electrode and the positive current collector can be welded through one through hole X, and the negative electrode and the negative current collector can be welded through the other through hole X. If the shortest distance B between the two through holes X is too large, the distance between the solder marks of the positive electrode tab and the positive current collector and the solder marks of the negative electrode tab and the negative current collector will be too large. Given a fixed current collector area, this excessive distance will result in an insufficient solder area for the first electrode tab (including both the positive and negative electrodes) and the current collector, thus affecting current flow performance. If the shortest distance B between the two through holes X is too small, the area of ​​the cover plate 2 between the two through holes X is prone to breakage, leading to poor strength of the cover plate 2. By controlling the shortest distance B between the two through holes X within a certain range, both current flow performance and the strength of the cover plate 2 can be guaranteed.

[0028] In some embodiments, the first tab is either a positive or negative tab, and the battery cell 3 includes a second tab disposed at the end of the battery cell body away from the cover plate 2. The second tab is either a positive or negative tab, and the polarities of the first and second tabs are different. In this case, only one type of tab and current collector need to be welded through the through hole X. Therefore, the area of ​​the through hole X can be appropriately smaller, and the range of the ratio A of the area of ​​the through hole X on the second end face 22 and the area of ​​the second end face 22 can be further narrowed to: 0.03 ≤ A < 0.05. For example, the value of A can be 0.03, 0.035, 0.04, 0.045, or 0.049.

[0029] In some embodiments, the first electrode includes a positive electrode and a negative electrode. The cover plate 2 has a first electrode post 5 and a second electrode post, with opposite polarities. The current collector includes a first current collector 41 and a second current collector 42. One side of the first current collector 41 and one side of the second current collector 42 are welded to the positive electrode post, and the other side is welded to the negative electrode post. The other side of the first current collector 41 and the other side of the second current collector 42 are welded to the first electrode post 5, and the other side is welded to the second electrode post, such that the first electrode post 5 and the second electrode post respectively serve as two electrodes of different polarities in the cylindrical battery.

[0030] In some embodiments, as shown in 5, a first annular groove 22a is provided on the second end face 22 of the cover plate 2, and an annular boss 1a is provided on the end face of the housing 1 near the cover plate 2. The annular boss 1a is at least partially located in the first annular groove 22a.

[0031] In some embodiments, such as Figure 5 As shown, a sealing element 6 is installed between the side of the annular boss 1a near the receiving cavity and the side of the first annular groove 22a near the receiving cavity to achieve a seal between the cover plate 2 and the housing 1. Specifically, in the illustrated embodiment, the outer side of the annular boss 1a fits against the outer side wall of the first annular groove 22a, which is more conducive to ensuring sealing performance. The through hole X is located within the annular space enclosed by the inner side wall of the first annular groove 22a. On the second end face 22, the range of the shortest distance C between the through hole X and the inner side wall of the first annular groove 22a is: 2mm≤C≤30mm. If the shortest distance C between the through hole X and the inner side wall of the first annular groove 22a is too large, the area of ​​the through hole X will be limited, affecting the welding operation and the release of welding heat. If the shortest distance C between the through hole X and the inner side wall of the first annular groove 22a is too small, the welding heat released through the through hole X will easily cause the sealing element 6 to deform and fail, affecting the sealing performance. By controlling the shortest distance C between the through hole X and the inner wall of the first annular groove 22a to be within the range of 2mm-30mm, it is possible to avoid both the limitation of the area of ​​the through hole X and the influence of welding heat on the sealing performance.

[0032] In some embodiments, such as Figure 3 or Figure 4 As shown, a second annular groove 21a is provided on the first end face 21 of the cover plate 2. The second annular groove 21a is located within the annular space enclosed by the inner wall of the first annular groove 22a, and the through hole X is located within the annular space enclosed by the inner wall of the second annular groove 21a. The second annular groove 21a can block some of the welding heat from being transferred from the through hole X to the first annular groove 22a, thereby helping to reduce the adverse effects of welding heat on the seal 6 inside the first annular groove 22a.

[0033] The above examples illustrate the principles and implementation methods of this application. The descriptions of the embodiments are merely for the purpose of helping to understand the methods and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A cover plate assembly for a cylindrical battery, characterized in that, The cover plate assembly includes a cover plate (2) and a collector plate. The cover plate (2) is provided with a first pole post (5) and at least one through hole (X). The collector plate is located at one end of the cover plate (2). The cover plate (2) has a first end face (21) relatively far away from the collector plate and a second end face (22) relatively close to the collector plate. The through hole (X) extends from the first end face (21) to the second end face (22). The orthographic projection of the collector plate on the second end face (22) at least partially coincides with the through hole (X). The ratio of the area of ​​the through hole (X) on the second end face (22) to the area of ​​the second end face (22) is A. The range of A is: 0.03≤A≤0.

1.

2. A cylindrical battery, characterized in that, The cylindrical battery includes the cover plate assembly as described in claim 1, and further includes a housing (1), a cell (3), and a sealing member. The housing (1) has an opening. The cover plate (2) is welded to the housing (1) and closes the opening. The cell (3) is located in the receiving cavity formed by the housing (1) and the cover plate (2). The cell (3) includes a cell body and a first electrode. The first electrode is disposed at one end of the cell body near the cover plate (2). The current collector is located between the cover plate (2) and the cell (3). The current collector is welded to the first electrode. The orthographic projection of the current collector and the first electrode on the second end face (22) of the cover plate (2) at least partially coincides with the through hole (X) on the cover plate (2). The sealing member is connected to the cover plate (2) and closes the through hole (X).

3. The cylindrical battery according to claim 2, characterized in that, The orthographic projection of the solder mark of the collector plate and the first electrode tab on the second end face (22) is completely within the range of the through hole (X).

4. The cylindrical battery according to claim 2, characterized in that, The first electrode includes a positive electrode and a negative electrode, and the ratio A of the area of ​​the through hole (X) on the second end face (22) to the area of ​​the second end face (22) is in the range of 0.05≤A≤0.

1.

5. The cylindrical battery according to claim 4, characterized in that, The current collector includes a first current collector (41) and a second current collector (42). One side of the first current collector (41) and one side of the second current collector (42) are welded to the positive electrode tab and the other side is welded to the negative electrode tab. The other side of the first current collector (41) and the other side of the second current collector (42) are welded to the first pole post (5) and the other side is welded to the cover plate (2). The ratio A of the area of ​​the through hole (X) on the second end face (22) to the area of ​​the second end face (22) is in the range of 0.06≤A≤0.

09.

6. The cylindrical battery according to claim 4, characterized in that, The cover plate (2) is provided with two through holes (X). On the second end face (22), the shortest distance B between the two through holes (X) is in the range of 8mm≤B≤35mm.

7. The cylindrical battery according to claim 2, characterized in that, The first tab is either a positive tab or a negative tab. The battery cell (3) includes a second tab. The second tab is disposed at the end of the battery cell body away from the cover plate (2). The second tab is either a positive tab or a negative tab. The first tab and the second tab have different polarities. The ratio A of the area of ​​the through hole (X) on the second end face (22) to the area of ​​the second end face (22) is in the range of 0.03≤A<0.

05.

8. The cylindrical battery according to claim 2, characterized in that, The second end face (22) of the cover plate (2) is provided with a first annular groove (22a), and the end face of the housing (1) near the cover plate (2) is provided with an annular boss (1a), and the annular boss (1a) is at least partially located in the first annular groove (22a).

9. The cylindrical battery according to claim 8, characterized in that, A sealing element (6) is installed between the side of the annular boss (1a) near the receiving cavity and the side of the first annular groove (22a) near the receiving cavity. The through hole (X) is located in the annular space enclosed by the inner wall of the first annular groove (22a). On the second end face (22) of the cover plate (2), the shortest distance C between the through hole (X) and the inner wall of the first annular groove (22a) is in the range of 2mm≤C≤30mm.

10. The cylindrical battery according to claim 9, characterized in that, The cover plate (2) has a second annular groove (21a) on the first end face (21). The second annular groove (21a) is located in the annular space formed by the inner sidewall of the first annular groove (22a). The through hole (X) is located in the annular space formed by the inner sidewall of the second annular groove (21a).

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