Button battery and method for manufacturing the same

Abstract

The present invention relates to a button battery and a manufacturing method thereof. The button battery comprises a battery cell, a shell and a cover assembly. An opening is provided at one end of the shell, and the battery cell is installed in the shell; the cover assembly comprises a ring cover, an insulating rubber ring and a pole cover. The insulating rubber ring comprises an annular body and an annular rubber strip connected to the lower surface of the annular body. The cross-sectional shape of the annular rubber strip is wedge-shaped. An annular wedge-shaped groove matching the cross-sectional shape of the annular rubber strip is formed between the inner side surface of the ring cover and the outer side surface of the pole cover. The annular rubber strip is embedded in the annular wedge-shaped groove, and the outer edge of the ring cover is sealed and connected to the open end of the shell. The button battery of the present invention makes the annular rubber strip of the insulating rubber ring embedded in the annular wedge-shaped groove, so that the outer side surface of the annular rubber strip is in close contact with the inner side surface of the ring cover, and the inner side surface of the annular rubber strip is in close contact with the outer side surface of the pole cover, thereby improving the sealing performance of the cover assembly, and can effectively seal the inside of the shell to prevent electrolyte leakage and water ingress.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion batteries, and in particular relates to a button battery and a manufacturing method thereof. Background Art

[0002] Lithium-ion batteries have high energy density, high operating voltage, low self-discharge rate and no memory effect. They are widely used in notebooks, power tools, electric vehicles and other fields, providing them with stable and safe power output.

[0003] At present, the shell of a lithium-ion battery has an electrolyte and an electrolyte sealing structure inside, and the two ends of the shell are sealed with an upper cover plate and a lower cover plate respectively. In order to prevent the electrolyte inside the lithium-ion battery from leaking from the upper cover plate to the outside when the electrolyte sealing structure fails, causing corrosion to the surrounding lithium-ion batteries, a sealing ring is usually set between the upper cover plate and the pole for sealing in the prior art. However, when the electrolyte inside the lithium-ion battery leaks, the internal pressure is relatively large, and it is difficult for the sealing ring to effectively seal the leaked electrolyte, and the electrolyte will still leak to the outside. That is, the existing lithium-ion batteries have poor sealing performance and cannot effectively seal the inside of the battery shell, which is prone to electrolyte leakage or water damage. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the problem in the prior art that the lithium ion battery has poor sealing performance and cannot effectively seal the inside of the battery shell, a button battery and a manufacturing method thereof are provided.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a button battery, comprising a battery cell, a shell and a cover assembly, wherein the shell is a barrel-shaped structure with an opening at one end, and the battery cell is installed in the shell;

[0006] The cover plate assembly includes a ring cover, an insulating rubber ring and a pole cover plate. The insulating rubber ring includes an annular main body and an annular rubber strip connected to the lower surface of the annular main body. The cross-sectional shape of the annular rubber strip is a wedge-shaped shape with a small upper end and a large lower end. An annular wedge-shaped groove matching the cross-sectional shape of the annular rubber strip is formed between the inner side surface of the ring cover and the outer side surface of the pole cover plate. The annular rubber strip is embedded in the annular wedge-shaped groove, and the outer edge of the ring cover is sealed and connected to the open end of the shell.

[0007] Optionally, the battery cell comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet leads to a positive electrode tab, the negative electrode sheet leads to a negative electrode tab, the positive electrode tab is connected to the pole cover plate, and the negative electrode tab is connected to the bottom wall of the shell;

[0008] The cross-sectional shape of the pole cover plate formed by cutting along the longitudinal direction of the button battery is a "J" shape.

[0009] Optionally, the ring cover includes an integrally connected annular cover and an annular ring, the annular ring is connected to the lower surface of the annular cover, the inner side surface of the annular ring is welded to the outer side surface of the shell, the lower surface of the annular cover is tightly attached to the end surface of the open end of the shell, and the annular wedge groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

[0010] Optionally, an insulating pin is inserted in the center of the battery cell, the longitudinal cross-section of the insulating pin is an I-shape, the upper end surface of the insulating pin supports the positive electrode tab, and the lower end surface of the insulating pin abuts against the negative electrode tab;

[0011] The upper end surface of the battery core is provided with an insulating magnetic isolation layer, and the inner side surface of the shell is provided with an insulating inner layer; the insulating magnetic isolation layer includes a metal partition and a polypropylene glue layer covering the upper surface of the metal partition, and the material of the insulating inner layer is polypropylene;

[0012] The insulating inner layer is provided with an avoidance hole for the negative electrode tab to pass through, the negative electrode tab passes through the avoidance hole and is welded to the bottom wall of the shell, and the positive electrode tab is welded to the pole cover plate.

[0013] Optionally, the ring cover includes an integrally connected annular cover and an annular convex strip, the annular convex strip is connected to the lower surface of the annular cover, and the longitudinal cross-section of the ring cover is T-shaped; the lower surface of the annular cover is tightly attached to the end surface of the open end of the shell, the annular convex strip extends into the shell, the outer side surface of the annular convex strip is tightly pressed against the inner side surface of the shell, and a gap is left between the inner side surface of the annular convex strip and the battery cell; the annular wedge-shaped groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

[0014] Optionally, the ring cover includes an annular cover, an annular outer ring and an annular inner ring that are integrally connected, the annular outer ring and the annular inner ring are sequentially connected to the lower surface of the annular cover from the outside to the inside, and an annular groove is formed between the annular outer ring and the annular inner ring; the open end of the shell is inserted into the annular groove, the inner side surface of the annular outer ring is welded to the outer side surface of the shell, and the outer side surface of the annular inner ring is pressed against the inner side surface of the shell; the lower surface of the annular cover is tightly attached to the end surface of the open end of the shell, and the annular wedge groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

[0015] According to the button battery of the embodiment of the present invention, an annular wedge-shaped groove is formed between the inner side surface of the ring cover and the outer side surface of the pole cover plate, and the annular rubber strip of the insulating rubber ring is embedded in the annular wedge-shaped groove; the cross-section of the annular rubber strip is wedge-shaped, so that the annular rubber strip is not easy to fall off, and the outer side surface of the annular rubber strip is in close contact with the inner side surface of the ring cover, and the inner side surface of the annular rubber strip is in close contact with the outer side surface of the pole cover plate; at the same time, the lower surface of the annular body is pressed tightly against the upper surfaces of the pole cover plate and the ring cover, and the outer edge of the ring cover is sealed and connected to the open end of the shell; thereby, the sealing performance of the entire cover assembly is greatly improved, and the inside of the shell can be effectively sealed to prevent electrolyte leakage and water ingress.

[0016] On the other hand, an embodiment of the present invention further provides a method for manufacturing a button battery, comprising the following steps:

[0017] S1. Form a first microstructure by laser sintering the surface where the ring cover contacts the insulating rubber ring, wherein the first microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove; form a second microstructure by laser sintering the surface where the pole cover contacts the insulating rubber ring, wherein the second microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove;

[0018] S2, hot pressing the ring cover, the insulating rubber ring and the pole cover together through an injection mold, so that the annular rubber strip of the insulating rubber ring is embedded between the pole cover and the ring cover, and the outer side of the annular rubber strip is squeezed into the first micro structure, and the inner side of the annular rubber strip is squeezed into the second micro structure;

[0019] S3, laser welding the annular ring of the ring cover onto the outer side surface of the shell.

[0020] Optionally, the specific step of S3 includes: laser welding the gap between the lower surface of the annular ring and the outer side surface of the shell.

[0021] Optionally, the specific step of S3 includes: performing laser welding from the outer side surface of the annular ring toward the outer side surface of the shell, so that the laser welding weld connects the inner side surface of the annular ring and the outer side surface of the shell.

[0022] Optionally, the annular ring is a stepped ring, and the specific step of S3 includes: performing laser welding from the outer side surface of the small diameter segment of the annular ring toward the outer side surface of the shell, so that the laser welding weld connects the inner side surface of the small diameter segment of the annular ring and the outer side surface of the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the three-dimensional structure of a button battery provided in the first embodiment of the present invention;

[0024] Figure 2 is a schematic structural diagram of a button-type battery provided by the first embodiment of the present invention after being cut longitudinally;

[0025] Figure 3 yes Figure 2 A partial enlarged view of the middle A;

[0026] Figure 4 yes Figure 2 A partial enlarged view of point B in the middle;

[0027] Figure 5 Schematic diagram of welding points of a button-type battery provided by the first embodiment of the present invention after the annular ring and the shell are welded by the first welding method;

[0028] Figure 6 Schematic diagram of the initial welding position when the annular ring and the shell are welded by the second welding method for the button-type battery provided by the first embodiment of the present invention;

[0029] Figure 7 Schematic diagram of the initial welding position when the annular ring and the shell are welded by the third welding method for the button-type battery provided by the first embodiment of the present invention;

[0030] Figure 8 It is a partial enlarged schematic diagram of the connection between the ring cover and the shell of the button battery provided by the second embodiment of the present invention;

[0031] Fig. 9 It is a partial enlarged schematic diagram of the connection between the ring cover and the shell of the button battery provided in the third embodiment of the present invention.

[0032] The reference numerals in the specification are as follows:

[0033] 1. Shell; 11. Insulating inner layer; 11a. Avoidance hole;

[0034] 2. Battery cell; 21. Positive pole tab; 22. Negative pole tab; 23. Insulating magnetic isolation layer;

[0035] 3. Cover plate assembly; 31. Ring cover; 311. Ring cover; 312. Ring ring; 313. Ring convex strip; 314. Ring outer ring; 315. Ring inner ring; 32. Insulating rubber ring; 321. Ring body; 322. Ring rubber strip; 33. Pole cover;

[0036] 4. Insulating pins. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] It should be noted that the orientation terms such as upper, lower, inner, and outer in the following text are only relative concepts to each other and should not be considered restrictive.

[0039] As Figure 1-4 shown, the button cell provided by the first embodiment of the present invention includes a battery core 2, a housing 1, and a cover plate assembly 3. The housing 1 is a barrel-shaped structure with an opening at one end, and the battery core 2 is installed inside the housing 1.

[0040] The cover plate assembly 3 includes a ring cover 31, an insulating rubber ring 32, and a pole cover plate 33. The insulating rubber ring 32 includes an annular main body 321 and an annular rubber strip 322 connected to the lower surface of the annular main body 321. The cross-sectional shape of the annular rubber strip 322 is a wedge shape with a smaller upper end and a larger lower end. A ring-shaped wedge groove matching the cross-sectional shape of the annular rubber strip 322 is formed between the inner side surface of the ring cover 31 and the outer side surface of the pole cover plate 33. The annular rubber strip 322 is embedded in the ring-shaped wedge groove to seal and connect the ring cover 31, the insulating rubber ring 32, and the pole cover plate 33. The outer edge of the ring cover 31 is sealed and connected to the opening end of the housing 1. The ring cover 31 is made of metal.

[0041] In the first embodiment, the battery core 2 includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. The positive electrode plate leads out a positive electrode tab 21, the negative electrode plate leads out a negative electrode tab 22. The positive electrode tab 21 is connected to the pole cover plate 33, and the negative electrode tab 22 is connected to the bottom wall of the housing 1.

[0042] In the first embodiment, the cross-sectional shape formed by longitudinally剖切 the pole cover plate 33 along the button cell is a "ji" character shape. This shape of the pole cover plate 33 can make the upper surface of its outer edge closely adhere to the lower surface of the annular main body 321, which is beneficial to its sealed connection with the insulating rubber ring 32 and improves the sealing performance of the entire cover plate assembly 3.

[0043] In the first embodiment, the ring cover 31 includes an integrally connected annular cover 311 and an annular ring 312. The annular ring 312 is connected to the outer edge of the annular cover 311. The inner side surface of the annular ring 312 is welded to the outer side surface of the housing 1. The lower surface of the annular cover 311 closely adheres to the end surface of the opening end of the housing 1. The ring-shaped wedge groove is formed between the inner side surface of the annular cover 311 and the outer side surface of the pole cover plate 33.

[0044] In the first embodiment, an insulating pin 4 is inserted in the center of the battery cell 2, and the longitudinal cross-section of the insulating pin 4 is an I-shaped, the upper end surface of the insulating pin 4 supports the positive pole lug 21, and the lower end surface of the insulating pin 4 abuts the negative pole lug 22. The insulating pin 4 supports the positive pole lug 21 to facilitate the welding of the positive pole lug and the pole cover 33. Preferably, the insulating pin 4 is made of non-metallic material, and the upper and lower ends of the insulating pin 4 are both provided with a hexagonal head.

[0045] In the first embodiment, an insulating magnetic isolation layer 23 is provided on the upper end surface of the battery core 2, and an insulating inner layer 11 is provided on the inner side surface of the shell 1; the insulating magnetic isolation layer 23 includes a metal partition (not shown in the figure) and a polypropylene adhesive layer covering the upper surface of the metal partition, and the insulating inner layer 11 is made of polypropylene. The insulating magnetic isolation layer 23 can shield the magnetic field and insulate from the cover plate assembly 3, and the insulating inner layer 11 can insulate the shell 1 from the battery core 2.

[0046] like Figure 3 As shown, the insulating inner layer 11 is provided with an escape hole 11a for the negative electrode tab 22 to pass through, and the negative electrode tab 22 passes through the escape hole 11a and is welded to the bottom wall of the housing 1. The positive electrode tab 21 is welded to the pole cover plate 33.

[0047] In the button-type battery provided by the first embodiment of the present invention, an annular wedge-shaped groove is formed between the inner side surface of the ring cover and the outer side surface of the pole cover plate, and the annular rubber strip of the insulating rubber ring is embedded in the annular wedge-shaped groove; the cross-section of the annular rubber strip is wedge-shaped, so that the annular rubber strip is not easy to fall off, and the outer side surface of the annular rubber strip is in close contact with the inner side surface of the ring cover, and the inner side surface of the annular rubber strip is in close contact with the outer side surface of the pole cover plate; at the same time, the lower surface of the annular body is tightly pressed against the upper surface of the pole cover plate and the ring cover, and the outer edge of the ring cover is sealed and connected to the open end of the shell; thereby, the sealing performance of the entire cover assembly is greatly improved, and the inside of the shell can be effectively sealed to prevent electrolyte leakage and water ingress.

[0048] In addition, the first embodiment of the present invention further provides a method for manufacturing a button battery, comprising the following steps:

[0049] S1. The surface where the ring cover 31 contacts the insulating rubber ring 32 is formed into a first microstructure by laser sintering, wherein the first microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove; the surface where the pole cover plate 33 contacts the insulating rubber ring 32 is formed into a second microstructure by laser sintering, wherein the second microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove.

[0050] S2. The ring cover 31, the insulating rubber ring 32 and the pole cover plate 33 are hot-pressed together by an injection mold, so that the annular rubber strip 322 of the insulating rubber ring 32 is embedded between the pole cover plate 33 and the ring cover 31, and the outer side surface of the annular rubber strip 322 is squeezed into the first micro structure, and the inner side surface of the annular rubber strip 322 is squeezed into the second micro structure.

[0051] S3, laser welding the annular ring 312 of the ring cover 31 to the outer surface of the shell 1.

[0052] In the first embodiment, the Figure 5 When the annular ring and the shell are welded by the first welding method shown, the specific step S3 includes: laser welding the gap between the lower surface of the annular ring 312 and the outer side surface of the shell 1.

[0053] In the first embodiment, the Figure 6 When the annular ring and the shell are welded in the second welding method shown, the specific step S3 includes: performing laser welding from the outer side of the annular ring 312 toward the outer side of the shell 1, so that the laser welding weld point connects the inner side of the annular ring 312 and the outer side of the shell 1. In this process, the starting position of the laser welding weld point is as shown in FIG. Figure 6 shown.

[0054] In the first embodiment, the annular ring 312 is a stepped ring. Figure 7 When the annular ring and the shell are welded in the third welding method shown, the specific step S3 includes: performing laser welding from the outer side surface of the small diameter section of the annular ring 312 toward the outer side surface of the shell 1, so that the laser welding weld point connects the inner side surface of the small diameter section of the annular ring 312 and the outer side surface of the shell 1. In this process, the starting position of the laser welding weld point is as shown in FIG. Figure 7 shown.

[0055] Second embodiment

[0056] See also Figure 8 The button battery provided in the second embodiment of the present invention is different from the first embodiment in that the ring cover 31 includes an annular cover 311 and an annular ridge 313 which are integrally connected, the annular ridge 313 is connected to the lower surface of the annular cover 311, and the longitudinal section of the ring cover 31 is T-shaped; the lower surface of the annular cover 311 is tightly attached to the end surface of the opening end of the shell 1, the annular ridge 313 extends into the shell 1, the outer side surface of the annular ridge 313 is tightly pressed against the inner side surface of the shell 1, and a gap is left between the inner side surface of the annular ridge 313 and the battery cell 2; the annular wedge groove is formed between the inner side surface of the annular cover 311 and the outer side surface of the pole cover plate 33.

[0057] Third embodiment

[0058] See also Fig. 9 The button battery provided in the third embodiment of the present invention is different from the first embodiment in that the ring cover 31 includes an annular cover 311, an annular outer ring 314 and an annular inner ring 315 which are integrally connected, and the annular outer ring 314 and the annular inner ring 315 are sequentially connected on the lower surface of the annular cover 311 from the outside to the inside, and an annular groove is formed between the annular outer ring 314 and the annular inner ring 315; the opening end of the shell 1 is inserted into the annular groove, the inner side surface of the annular outer ring 314 is welded to the outer side surface of the shell 1, and the outer side surface of the annular inner ring 315 is pressed against the inner side surface of the shell 1; the lower surface of the annular cover 311 is tightly attached to the end surface of the opening end of the shell 1, and the annular wedge groove is formed between the inner side surface of the annular cover 311 and the outer side surface of the pole cover plate 33.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A button battery, characterized in that: It includes a battery cell, a shell and a cover plate assembly, wherein the shell is a barrel-shaped structure with an opening at one end, and the battery cell is installed in the shell; The cover plate assembly comprises a ring cover, an insulating rubber ring and a pole cover plate, wherein the insulating rubber ring comprises an annular body and an annular rubber strip connected to the lower surface of the annular body, wherein the cross-sectional shape of the annular rubber strip is a wedge shape with a small upper end and a large lower end, and an annular wedge groove matching the cross-sectional shape of the annular rubber strip is formed between the inner side surface of the ring cover and the outer side surface of the pole cover plate, and the outer edge of the ring cover is sealed and connected to the open end of the shell; The surface of the ring cover in contact with the insulating rubber ring is formed with a first microstructure; the surface of the pole cover in contact with the insulating rubber ring is formed with a second microstructure; The ring cover, the insulating rubber ring and the pole cover are heat-pressed together; the annular rubber strip is embedded in the annular wedge-shaped groove, so that the annular rubber strip is embedded between the pole cover and the ring cover, and the outer side of the annular rubber strip is squeezed into the first micro-structure, and the inner side of the annular rubber strip is squeezed into the second micro-structure; The upper end surface of the battery core is provided with an insulating magnetic isolation layer; The first microstructure is one of a rectangular groove, a triangular groove or a U-shaped groove; The second microstructure is one of a rectangular groove, a triangular groove or a U-shaped groove.

2. The button battery according to claim 1, characterized in that: The battery cell comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet leads to a positive electrode tab, the negative electrode sheet leads to a negative electrode tab, the positive electrode tab is connected to the pole cover plate, and the negative electrode tab is connected to the bottom wall of the shell; The cross-sectional shape of the pole cover plate formed by cutting along the longitudinal direction of the button battery is a "J" shape.

3. The button battery according to claim 1, characterized in that: The ring cover includes an annular cover and an annular ring that are integrally connected, the annular ring is connected to the lower surface of the annular cover, the inner side surface of the annular ring is welded to the outer side surface of the shell, the lower surface of the annular cover is tightly attached to the end surface of the open end of the shell, and the annular wedge groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

4. The button battery according to claim 2, characterized in that: An insulating pin is inserted in the center of the battery cell, the longitudinal cross-section of the insulating pin is an I-shaped, the upper end surface of the insulating pin supports the positive electrode tab, and the lower end surface of the insulating pin abuts against the negative electrode tab; An insulating inner layer is provided on the inner side of the shell; the insulating magnetic isolation layer includes a metal partition and a polypropylene adhesive layer covering the upper surface of the metal partition, and the material of the insulating inner layer is polypropylene; The insulating inner layer is provided with an avoidance hole for the negative electrode tab to pass through, the negative electrode tab passes through the avoidance hole and is welded to the bottom wall of the shell, and the positive electrode tab is welded to the pole cover plate.

5. The button battery according to claim 1, characterized in that: The ring cover includes an annular cover and an annular convex strip connected in one piece, the annular convex strip is connected to the lower surface of the annular cover, and the longitudinal section of the ring cover is T-shaped; the lower surface of the annular cover is tightly attached to the end surface of the opening end of the shell, the annular convex strip extends into the shell, the outer side surface of the annular convex strip is tightly attached to the inner side surface of the shell, and a gap is left between the inner side surface of the annular convex strip and the battery cell; the annular wedge-shaped groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

6. The button battery according to claim 1, characterized in that: The ring cover includes an annular cover, an annular outer ring and an annular inner ring which are integrally connected, the annular outer ring and the annular inner ring are sequentially connected to the lower surface of the annular cover from the outside to the inside, and an annular groove is formed between the annular outer ring and the annular inner ring; the open end of the shell is inserted into the annular groove, the inner side surface of the annular outer ring is welded to the outer side surface of the shell, and the outer side surface of the annular inner ring is pressed against the inner side surface of the shell; the lower surface of the annular cover is tightly attached to the end surface of the open end of the shell, and the annular wedge groove is formed between the inner side surface of the annular cover and the outer side surface of the pole cover plate.

7. A method for manufacturing a button battery according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Form a first microstructure by laser sintering the surface where the ring cover contacts the insulating rubber ring, wherein the first microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove; form a second microstructure by laser sintering the surface where the pole cover contacts the insulating rubber ring, wherein the second microstructure is one of a rectangular groove, a triangular groove, or a U-shaped groove; S2, hot pressing the ring cover, the insulating rubber ring and the pole cover together through an injection mold, so that the annular rubber strip of the insulating rubber ring is embedded between the pole cover and the ring cover, and the outer side of the annular rubber strip is squeezed into the first micro structure, and the inner side of the annular rubber strip is squeezed into the second micro structure; S3, laser welding the annular ring of the ring cover onto the outer surface of the shell.

8. The method for manufacturing a button cell according to claim 7, characterized in that: The specific step of S3 includes: laser welding the gap between the lower surface of the annular ring and the outer side surface of the shell.

9. The method for manufacturing a button cell according to claim 7, characterized in that: The specific step of S3 includes: performing laser welding from the outer side surface of the annular ring toward the outer side surface of the shell, so that the laser welding welding point connects the inner side surface of the annular ring and the outer side surface of the shell.

10. The method for manufacturing a button cell according to claim 7, characterized in that: The annular ring is a stepped ring, and the specific step of S3 includes: performing laser welding from the outer side surface of the small diameter section of the annular ring toward the outer side surface of the shell, so that the laser welding weld connects the inner side surface of the small diameter section of the annular ring and the outer side surface of the shell.

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