Shell and button lithium battery

Abstract

The shell comprises a side wall and a bottom wall, the bottom wall is round, a buffer column and a central column are arranged on the inner side face of the bottom wall, the buffer column covers the surface of the bottom wall, the buffer column is of a conical structure, the buffer column inclines from the center of the bottom wall to the edge, and the central column is arranged on the bottom wall. The center column is arranged in the center of the bottom wall and protrudes out of the surface of the buffer column. Comprising. The button lithium battery disclosed by the utility model comprises the shell. According to the utility model, the buffer column, the central column and the insulating layer are arranged on the bottom wall of the shell, so that the probability of expansion of the shell under the acting force of the battery cell is reduced, the risk that the bottom wall of the shell is welded through is reduced, and the welding firmness is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular mainly to a shell and a button-type lithium battery. Background Art

[0002] The shell of button-type lithium batteries is made of metal, and the battery cell is installed inside the shell. The anode of the battery cell is welded to the bottom of the shell through the tab or current collector. As the market's requirements for the energy density of lithium batteries become higher and higher, the shell of button-type batteries is designed to be thinner and thinner to increase the energy density. However, because the bottom of the shell is too thin, there is a risk of welding through when the bottom of the shell is welded to the current collector or tab; and during the battery charging and discharging process, because the shell is thinner at the welding position, the shell is easily deformed and expanded under stress, and in serious cases, there will be risks such as leakage.

[0003] In view of this, it is necessary to improve the structure of the existing button battery. Utility Model Content

[0004] In view of the deficiencies of the prior art, the utility model provides a shell and a button-type lithium battery to solve the risks of the bottom of the existing button-type battery being easily welded through and easily deformed and expanded under stress due to the shell being too thin.

[0005] The utility model discloses a shell, including side walls and a bottom wall, wherein the bottom wall is circular, and a buffer column and a center column are arranged on the inner side surface of the bottom wall, the buffer column covers the surface of the bottom wall, the buffer column is a conical structure, the buffer column is inclined from the center of the bottom wall to the edge, the center column is arranged at the center of the bottom wall, and the center column protrudes from the surface of the buffer column.

[0006] Preferably, the central column is a cylindrical structure.

[0007] Preferably, the surface of the buffer column is covered with an insulating layer.

[0008] Preferably, the central column and the buffer column are both made of aluminum alloy.

[0009] Preferably, the insulating layer is made of ceramic material.

[0010] Preferably, the thickness of the central portion of the buffer column is b, 0.02mm≤b≤0.045mm.

[0011] Preferably, the height of the central column is between 0.08 and 0.15 mm.

[0012] Preferably, the thickness of the insulating layer is 3-5 um.

[0013] The utility model discloses a button-type lithium battery, comprising any of the above-mentioned shells, and also comprising a battery core, wherein the battery core is installed in the shell, the battery core is a winding core, the battery core has a winding pin hole, and the center column is inserted into the winding pin hole.

[0014] Preferably, the battery cell comprises an anode sheet, a cathode sheet and a separator, and the battery cell is connected with a tab, and the tab is connected to the anode sheet and the center column.

[0015] The beneficial effects of the utility model are:

[0016] By arranging a buffer column on the bottom wall of the shell, the buffer column adopts a structure that is inclined from the middle to both sides, thereby improving the structural strength of the bottom wall of the shell and reducing the probability of the shell expanding when subjected to the force of the battery cell. In addition, the center column protrudes from the bottom wall and the buffer column alone, and the risk of the bottom wall of the shell being welded through is reduced by welding the pole ear and the center column, thereby improving the firmness of the welding and achieving stable electrical conduction between the pole ear and the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 It is a cross-sectional view of the housing of the utility model;

[0019] Figure 2 It is a cross-sectional view of the button-type lithium battery of the present utility model.

[0020] Explanation of the reference numerals: 1. Shell; 11. Side wall; 12. Bottom wall; 13. Buffer column; 14. Center column; 15. Insulating layer; 2. Battery cell; 21. Anode sheet; 22. Cathode sheet; 23. Diaphragm; 24. Pinhole; 25. Ear. DETAILED DESCRIPTION

[0021] The following will disclose multiple embodiments of the present invention with diagrams. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the diagram, some conventional structures and parts will be depicted in a simple schematic manner in the diagram.

[0022] It should be noted that all directional indications such as up, down, left, right, front, back... in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish between parts or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0024] In order to further understand the content, features and effects of the utility model, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0025] Reference Figure 1 , is a shell disclosed in the utility model, which is used for button-type lithium batteries. The shell 1 is a cylindrical structure. The shell 1 is made of metal, preferably aluminum alloy. One end of the shell 1 is provided with an opening, and the other end is a closed end. The shell 1 includes a cylindrical side wall 11 and a circular bottom wall 12. A buffer column 13 and a center column 14 are arranged on the inner side of the bottom wall 12, wherein the buffer column 13 covers the surface of the bottom wall 12, and the buffer column 13 is a conical structure. The buffer column 13 is inclined from the middle of the bottom wall 12 to the edge of the bottom wall 12. The buffer column 13 The thickness of the middle part is greater than the thickness of the edge of the buffer column 13. The center column 14 is arranged at the center of the bottom wall 12. The center column 14 is cylindrical, and the center column 14 and the buffer column 13 are integrally arranged. The height of the center column 14 is greater than the thickness of the buffer column 13. One end of the center column 14 is fixed on the bottom wall 12, and the other end is located on the outside of the buffer column 13, that is, the center column 14 protrudes from the surface of the buffer column 13, which is convenient for welding with the pole ear 25; the surface of the buffer column 13 away from the bottom wall 12 is covered with an insulating layer 15, which is used to insulate the buffer column 13 and the battery cell 2 from each other.

[0026] Reference Figure 1Preferably, the central column 14 and the buffer column 13 are made of aluminum alloy, and the central column 14 and the buffer column 13 are made of the same material as the shell 1. Since the shell 1 is used for anode conduction, when the tab is connected between the shell 1 and the central column 14, the same material of the three can ensure the consistency of the conductive effect; the central part of the buffer column 13 has a thickness of b, and the range of b is between 0.02mm and 0.045mm. The height of the central column 14 is the distance between the end face of the central column 14 and the bottom wall 12, and the range of the height h of the central column 14 is 0.08~0. 15mm, and the diameter is between 1.3mm and 2.5mm. Preferably, the central column 14 with a diameter of 1.3mm, 1.5mm, 2.0mm, or 2.5mm can be used; the insulating layer 15 is made of ceramic material, and the thickness of the insulating layer 15 is 3 to 5um, which is smaller than that of conventional insulating materials. It can be directly coated on the buffer column 13, so that the bottom of the shell 1 occupies less space in the shell 1, and the insulating layer 15 made of ceramic material does not have a glue layer, so there is no problem of affecting the fluidity of the electrolyte, and the smoothness of the electrolyte flow can be ensured. The inclined buffer column 13 can withstand the expansion force of the battery cell 2 during the charging and discharging process of the battery, reduce the probability of deformation of the shell 1, and on the other hand, it can play an insulating role under the action of the insulating layer 15 to improve safety performance.

[0027] Reference Figure 1 Specifically, the inclination angle between the surface of the buffer column 13 and the bottom wall 12 is α, α=arctan(b / (D÷2-d)), where b is the maximum thickness of the buffer column 13, D is the inner diameter of the shell 1, d is the diameter of the center column 14, α is proportional to b, and the range of b is between 0.02mm and 0.045mm: if b is lower than 0.02mm, on the one hand, since the buffer column 13 is made of aluminum alloy, its structural stability cannot be guaranteed, and on the other hand, α is too small, and the buffering effect on the expansion and extrusion of the battery cell during the charging and discharging process is not good; if b>0.045mm, the sum of the thickness of the buffer column 13 and the insulating layer 15 is>0.05mm, which will reduce the space utilization inside the shell 1 and cause capacity loss.

[0028] Reference Figure 2The button battery disclosed in the utility model includes the above-mentioned shell 1, and also includes a battery cell 2. The battery cell 2 includes an anode sheet 21, a cathode sheet 22 and a separator 23. The anode sheet 21, the cathode sheet 22 and the separator 23 overlap with each other and are wound into a winding core. The battery cell 2 is installed inside the shell 1. A winding needle hole 24 is provided in the middle of the battery cell 2. The diameter of the winding needle hole 24 is the same as that of the winding needle, which is used for inserting the winding needle. The diameter of the winding needle hole 24 is preferably one of 1.3mm, 1.5mm, 2.0mm, and 2.5mm. When the battery cell 2 is wound, the winding needle hole 24 is used for inserting the winding needle. After the battery cell 2 is wound, the winding needle is pulled out to form the above-mentioned winding needle hole 24. Preferably, the diameter of the winding needle hole 24 is larger than the diameter of the center column 14, so that the center column 14 can be inserted into the winding needle hole 24, providing more space for the battery cell 2 inside the shell 1, thereby improving the energy density of the battery.

[0029] Reference Figure 2 , the battery cell 2 is connected with a tab 25, which serves as an anode current collector. The tab 25 is a metal sheet structure. The tab 25 is connected to the anode sheet 21 on one hand, and to the center column 14 on the other hand, and the connection method is welding. Since the center column 14 is a convex structure, the thickness of the center column 14 is greater than the buffer column 13 and the bottom wall 12 of the shell 1. Therefore, welding the tab 25 to the center column 14 can avoid the bottom wall 12 of the shell 1 from being welded through, improve the firmness of the welding, and achieve stable electrical conduction between the tab 25 and the shell 1. Specifically, after the tab 25 is welded to the center column 14, the thickness of the welding position = the thickness of the bottom wall 12 + the height of the center column 14 - the melting depth of the welding position. The setting of the center column 14 makes it easier to make the thickness of the welding position ≥ the thickness of the bottom wall 12, thereby greatly reducing the risk of leakage caused by welding.

[0030] The implementation principle and beneficial effect of the utility model are as follows: by arranging a buffer column 13 on the bottom wall 12 of the shell 1, the buffer column 13 adopts a structure inclined from the middle to both sides, thereby improving the structural strength of the bottom wall 12 of the shell 1 and reducing the probability of the shell 1 expanding when subjected to the force of the battery cell 2; in addition, the center column 14 protrudes from the bottom wall 12 and the buffer column 13 alone, and the risk of the bottom wall 12 of the shell 1 being welded through is reduced by welding the pole ear 25 and the center column 14, thereby improving the firmness of the welding and achieving stable electrical conduction between the pole ear 25 and the shell 1.

[0031] The following uses Example 1 and Example 2 to further illustrate the size limitations of various parts in the structure of the utility model and the technical effects that can be achieved.

[0032] Example 1

[0033] This embodiment adopts 1154 button-type batteries, whose shell outer diameter is 10.80±0.03mm, inner diameter is 10.50±0.03mm, winding needle diameter is 1.5mm, shell thickness is 0.15mm, after the anode ear is welded, the conventional melting depth of the center column is 0.12-0.15mm. Tests on Example 1 show that the thickness range of the center column at the bottom of the shell needs to be 0.08-0.15mm to control the welding from penetrating the center column and the bottom wall, thereby ensuring that there is no risk of welding through the entire bottom wall. The thickness range of the buffer column from the edge to the center must be between 0.02 and 0.045mm, that is, the upper limit of the thickness of the central part of the buffer column is 0.045mm, and the thickness of the insulating layer covering the buffer column is 3 to 5um. Therefore, the sum of the thickness of the central part of the buffer column and the thickness of the insulating layer is at most 0.05mm, which is the same as the thickness of a conventional insulating sheet. Within this thickness range, the capacity loss is between 1 and 2.8%, and there is no additional capacity loss. If the thickness exceeds this, it will affect the space utilization inside the shell, resulting in a capacity loss of more than 2.8%, resulting in additional capacity loss; in addition, if the central part of the buffer column is ≤0.02mm, the inclination angle α of the buffer column is ≤0.005°. This angle is too small to achieve the effect of buffering expansion and extrusion.

[0034] Example 2

[0035] This embodiment adopts 1154 button-type batteries, whose shell outer diameter is 10.80±0.03mm, inner diameter is 10.60±0.03mm, winding needle diameter is 1.5mm, shell wall thickness is 0.10mm, and after the anode tab is welded, the melting depth of the center column is 0.12-0.15mm. Tests on Example 2 show that the thickness range of the center column at the bottom of the shell needs to be 0.10-0.15mm, so that the welding position thickness = bottom wall thickness + center column height - welding position melting depth ≥ bottom wall thickness.

[0036] It can be seen that the size range of each part in the structure of Example 1 and Example 2 ensures that there is no risk of welding leakage in the shell, while also having a high space utilization rate and being able to achieve the effect of buffering expansion and extrusion.

[0037] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A housing, characterized in that: The invention comprises a side wall (11) and a bottom wall (12); the bottom wall (12) is circular; a buffer column (13) and a center column (14) are arranged on the inner side surface of the bottom wall (12); the buffer column (13) covers the surface of the bottom wall (12); the buffer column (13) is a conical structure; the buffer column (13) is inclined from the center of the bottom wall (12) to the edge; the center column (14) is arranged at the center of the bottom wall (12); and the center column (14) protrudes from the surface of the buffer column (13).

2. The housing according to claim 1, characterized in that The central column (14) is a cylindrical structure.

3. The housing according to claim 1, characterized in that The surface of the buffer column (13) is covered with an insulating layer (15).

4. The housing according to any one of claims 1 to 3, characterized in that: The central column (14) and the buffer column (13) are both made of aluminum alloy.

5. The housing according to claim 3, characterized in that: The insulating layer (15) is made of ceramic material.

6. The housing according to claim 3, characterized in that: The thickness of the central part of the buffer column (13) is b, 0.02mm≤b≤0.045mm.

7. The housing according to claim 6, characterized in that The height of the central column (14) is between 0.08 and 0.15 mm.

8. The housing according to claim 6, characterized in that The thickness of the insulating layer (15) is 3-5 um.

9. A button lithium battery, characterized in that: It comprises a shell (1) as described in any one of claims 1 to 8, and also comprises a battery core (2), wherein the battery core (2) is installed in the shell (1), the battery core (2) is a winding core, the battery core (2) has a winding pin hole (24), and the center column (14) is inserted into the winding pin hole (24).

10. The button-type lithium battery according to claim 9, characterized in that: The battery cell (2) comprises an anode sheet (21), a cathode sheet (22) and a separator (23); the battery cell (2) is connected to a pole lug (25); the pole lug (25) is connected to the anode sheet (21) and the central column (14).

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