Button cell

Abstract

The utility model provides a button cell. The button cell comprises a positive electrode cover and a negative electrode cover, the positive electrode current collector is arranged in the positive electrode cover, and a through hole is formed in the bottom wall of the positive electrode current collector; the positive plate is accommodated in the positive current collector; the gasket assembly is connected to the positive electrode cover, the gasket assembly comprises a gasket and an elastic piece which are arranged in a split mode, the length of the gasket is L1, the length of the elastic piece is L2, L1 is larger than L2, the gasket and the elastic piece are connected in a crossed mode, the elastic piece is located in the positive electrode current collector, a protruding structure is arranged on the gasket and / or the elastic piece, and the protruding structure is connected with the gasket and / or the elastic piece. And the bulge structure penetrates through the through hole and is fixed on the positive plate.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a button battery. Background Art

[0002] In related technologies, button-type batteries primarily consist of a positive electrode cap, a negative electrode cap, a sealing ring, a positive electrode sheet, a negative electrode sheet, a positive current collector, a separator, and an electrolyte. Considering manufacturing processes and assembly costs, the positive electrode collector is typically configured as a sheet, mesh, or ring. During battery assembly, the positive electrode sheet and the positive current collector are assembled to form a positive electrode assembly, which is placed within the battery's inner cavity and encapsulated within the battery using a mold.

[0003] Because the positive electrode assembly relies on mold packaging pressure to secure it within the battery's interior, this single-use fixing method results in low reliability. This is especially true when button-type batteries are centrifuged at high speeds and high temperatures, such as 3300g centrifugal force at temperatures above 150°C. The positive electrode assembly is prone to severe shaking and misalignment, further leading to serious separation between the positive electrode assembly and the positive electrode cap, and easy collision between the positive electrode sheet and the electrolyte. This, in turn, severely impacts the stability of battery performance, rendering the battery unable to meet the requirements of demanding applications. Utility Model Content

[0004] An embodiment of the present utility model provides a button-type battery, which can improve the technical problem of unstable fixation of the positive electrode assembly inside the button-type battery.

[0005] An embodiment of the present utility model provides a button battery, comprising:

[0006] positive electrode cap;

[0007] A positive electrode current collector is arranged inside the positive electrode cover, and a through hole is provided on the bottom wall of the positive electrode current collector;

[0008] A positive electrode sheet, housed inside the positive electrode current collector;

[0009] A gasket assembly is connected to the positive electrode cover, and the gasket assembly includes a gasket and a spring sheet arranged separately. The length of the gasket is L1, and the length of the spring sheet is L2, L1>L2. The gasket and the spring sheet are cross-connected, and the two ends of the gasket are connected to the positive electrode collector. The spring sheet is located inside the positive electrode collector. A protrusion structure is provided on the gasket and / or the spring sheet, and the protrusion structure passes through the through hole and is fixed to the positive electrode sheet.

[0010] Beneficial effects of the embodiments of the present utility model:

[0011] In an embodiment of the present invention, a gasket assembly is added to the button battery, and the gasket assembly is connected to the positive electrode cover. The gasket assembly includes gaskets and springs that are cross-connected to each other, wherein the length L1 of the gasket is greater than the length L2 of the spring, so that both ends of the gasket are connected to the positive electrode collector, and the spring is located in the positive electrode collector. The raised structure provided on the gasket and / or spring is further fixed in the positive electrode sheet. Therefore, when the positive electrode cover bulges, the gasket assembly can further maintain the contact connection between the positive electrode cover and the positive electrode sheet and the positive electrode collector, thereby improving the stability of the internal structure of the button battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 is a cross-sectional view of a button battery provided by an embodiment of the present application from one perspective;

[0014] Figure 2 is a cross-sectional view of a button battery provided by an embodiment of the present application from another perspective;

[0015] Figure 3 is a cross-sectional view of a button battery provided in yet another embodiment of the present application from one perspective;

[0016] Figure 4 is a cross-sectional view of a button battery provided in yet another embodiment of the present application from yet another perspective;

[0017] Figure 5 is a perspective view of a gasket assembly provided by one embodiment of the present application;

[0018] Figure 6a is a perspective view of a gasket provided by an embodiment of the present application at one angle;

[0019] Figure 6b is a three-dimensional view of a gasket provided by an embodiment of the present application from another angle;

[0020] Figure 6c is a three-dimensional view of a gasket provided by an embodiment of the present application from another angle;

[0021] Figure 7a This is a three-dimensional diagram of a spring provided by an embodiment of the present application at one angle;

[0022] Figure 7bThis is a three-dimensional diagram of a spring provided by an embodiment of the present application from another angle;

[0023] Figure 7c is a cross-sectional view of a spring provided by an embodiment of the present application from another angle;

[0024] Figure 7d is a three-dimensional diagram of a spring provided in yet another embodiment of the present application;

[0025] Figure 8 is a schematic diagram of the welding area of ​​the spring and the gasket provided in one embodiment of the present application;

[0026] Figure 9a yes Figure 7c A partial enlarged view of the first structure;

[0027] Figure 9b yes Figure 7c A partial enlarged view of the second structure;

[0028] Figure 9c yes Figure 7c A partial enlarged view of the third structure;

[0029] Figure 10 is a partial cross-sectional view of a button battery provided in one embodiment of the present application;

[0030] Figure 10a is a partial cross-sectional view of a button battery provided in a comparative example of the present application;

[0031] Figure 10b is a partial cross-sectional view of a button battery provided in another comparative example of the present application;

[0032] Figure 11 is a schematic diagram of the welding area between the gasket assembly and the positive electrode cover of the present application;

[0033] Figure 12a is a perspective view of a gasket assembly provided in yet another embodiment of the present application;

[0034] Figure 12b is a perspective view of a gasket assembly provided in another embodiment of the present application;

[0035] Figure 13 An embodiment of the present application provides a cross-sectional view of a gasket assembly after being welded to a positive electrode cover;

[0036] Figure 14 An embodiment of the present application provides a three-dimensional diagram of a gasket assembly after being welded to a positive electrode cover;

[0037] Figure 15 One embodiment of the present application provides the position requirements of the first welding point of the gasket assembly and the positive cover

[0038] Figure 16a This is a cross-sectional view from one perspective of a button-type battery with a positive electrode cap bulging outward, provided by one embodiment of the present application;

[0039] Figure 16b This is a cross-sectional view of a button battery with a bulging positive electrode cap provided by an embodiment of the present application from another perspective;

[0040] Figure 17 This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in one embodiment of the present application. Figure 1 ;

[0041] Figure 18 This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in one embodiment of the present application. Figure 2 ;

[0042] Figure 19 This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in one embodiment of the present application. Figure 3 ;

[0043] Figure 20 This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in one embodiment of the present application. Figure 4 ;

[0044] Figure 21 is a schematic diagram of the construction lines of a gasket assembly provided by one embodiment of the present application;

[0045] Figure 22a This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in one embodiment of the present application. Figure 5 ;

[0046] Figure 22b This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in a comparative example of the present application;

[0047] Figure 22c This is a schematic diagram of the position structure of the gasket assembly and the positive electrode current collector provided in another comparative example of the present application;

[0048] Figure 23a This is a schematic diagram of the raw material structure of a gasket provided in one embodiment of the present application;

[0049] Figure 23b This is a schematic diagram of the raw material structure of the shrapnel provided in one embodiment of the present application;

[0050] Figure 23c This is a schematic diagram of the raw material structure of a gasket assembly provided by one embodiment of the present application;

[0051] Figure 24aThis is a schematic diagram of the partial structure of the spring provided in Example 1 of the present application;

[0052] Figure 24b This is a schematic diagram of the partial structure of the spring provided in Comparative Example 1 of the present application;

[0053] Figure 24c This is a schematic diagram of the partial structure of the spring provided in Comparative Example 2 of the present application;

[0054] Figure Number:

[0055] 1. Button cell; 11. Positive electrode cover; 111. Boss structure; 12. Negative electrode cover; 13. Sealing ring; 14. Positive electrode current collector; 141. Annular bottom wall; 142. Through hole; 15. Positive electrode sheet; 16. Negative electrode sheet; 17. Diaphragm; 100. Positive electrode assembly; 200. Negative electrode assembly; 20. Gasket assembly; 21. Gasket; 211. Gasket base; 212. Gasket boss; 213. Gasket receiving cavity; 2141. First end portion; 2142. Second end portion; 2143. First endpoint; 22. Spring ; 221, spring plate base; 2221, third end; 2222, fourth end; 2223, second end point; 223, spring plate boss; 224, spring plate receiving cavity; 23, raised structure; 231, first flange 231; 232, second flange; 241, first welding point; 242, second welding point; Q1, first area; Q2a, first part of second area; Q2b, second part of second area; Q3a, first part of third area; Q3b, second part of third area; Q4, area where the annular bottom wall is located; DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0057] In related technologies, button-type batteries primarily consist of a positive electrode cap, a negative electrode cap, a sealing ring, a positive electrode sheet, a negative electrode sheet, a positive current collector, a separator, and an electrolyte. Considering manufacturing processes and assembly costs, the positive electrode collector is typically configured as a sheet, mesh, or ring. During battery assembly, the positive electrode sheet and the positive current collector are assembled to form a positive electrode assembly, which is placed within the battery's inner cavity and encapsulated within the battery using a mold.

[0058] Because the positive electrode assembly relies on mold packaging pressure to secure it within the battery's interior, this single-use fixing method results in low reliability. This is especially true when button-type batteries are subjected to high-speed centrifugation and high-temperature conditions, where the positive electrode assembly is prone to severe shaking and misalignment. This can lead to serious separation between the positive electrode assembly and the positive electrode cap, and collisions between the positive electrode sheet and the electrolyte. This can severely impact the stability of battery performance, rendering the battery unable to meet the demands of demanding applications.

[0059] For example, when the battery is exposed to a high temperature of 150°C, the electrolyte gassing causes the internal pressure of the battery to increase, further causing the positive and negative electrode covers to deform and bulge, resulting in a gap between the positive electrode cover and the positive electrode sheet, increasing the battery's internal resistance and causing unqualified battery performance. When the battery is subjected to a high-speed centrifugal force of 3300g, because the positive electrode assembly is placed directly inside the positive electrode cover, there is no fixing or limiting function between the collector ring / positive electrode collector / current collector sheet and the positive electrode cover, which makes the positive electrode assembly easy to move inside the battery, and the positive electrode assembly collides with the electrolyte, which in turn leads to a decrease in the electrical performance stability of the button cell and even failure of the button cell.

[0060] As an energy source, button cells require stable power supply at temperatures between -40°C and 85°C. High internal resistance can lead to shorter battery life, reduced capacity, faster self-discharge, lower voltage, and self-heating. Therefore, internal resistance is a key indicator for evaluating the reliability and stability of button cells. Initial internal resistance is typically required to be below 10Ω, and below 20Ω after one week of storage at 85°C.

[0061] With the development of society and changes in the market, the application environment of button batteries is becoming increasingly harsh. For example, button batteries are required to maintain stable power supply under high temperature, high humidity, high pressure, high frequency vibration and high-speed centrifugation conditions. Tests have found that when the temperature of the button battery application scenario increases from 85°C to 125°C, the positive electrode cap of the button battery structure in the related art will experience severe bulging as the temperature rises. The gap between the positive electrode cap and the positive current collector increases, which in turn leads to a decrease in the current collection effect of the positive current collector, resulting in a sharp increase in the internal resistance of the button battery, which in turn makes the button battery unable to meet the requirements of current application scenarios.

[0062] With the increasing market demand for use under high-speed centrifugal conditions, button batteries are required to continue to work normally under a high-speed centrifugal force of 3300g. However, in related technologies, the positive electrode assembly structure moves and deviates and has inelastic contact under a high-speed centrifugal force of 3300g, resulting in an increase in the internal resistance of the button battery, which in turn leads to unstable electrical performance of the button battery, making the button battery unable to meet the requirements of current application scenarios.

[0063] In order to improve the stability of the electrical performance of the button battery in extreme application scenarios, the internal structure of the button battery is optimized in this application.

[0064] refer to Figures 1 to 4 As shown, the present invention provides a button battery 1, which includes a positive electrode cover 11, a negative electrode cover 12, a sealing ring 13, a positive electrode collector 14, a positive electrode sheet 15, a negative electrode sheet 16, a separator 17 and an electrolyte 18.

[0065] The positive electrode cover 11 is configured as an open cover structure, such as Figure 1 and Figure 2 As shown, the outer side surface of the positive electrode cover 11 can be constructed as a vertical surface structure, such as Figure 3 and Figure 4 As shown, a boss structure may also be provided on the outer side of the positive electrode cover 11 .

[0066] The negative electrode cover 12 is configured as an open cover-shaped structure. The inner diameter and outer diameter of the positive electrode cover 11 are larger than those of the negative electrode cover 12 , so that the positive electrode cover 11 can cover the outside of the negative electrode cover 12 .

[0067] A sealing ring 13 is provided at the connection between the positive electrode cap 11 and the negative electrode cap 12. The sealing ring 13 wraps around at least a portion of the wall of the negative electrode cap 12, thereby forming a sealed connection between the positive electrode cap 11 and the negative electrode cap 12. The sealing ring 13 also provides insulation between the positive electrode cap 11 and the negative electrode cap 12.

[0068] The positive electrode current collector 14 includes an annular bottom wall 141 and a side wall 143 circumferentially connected to the annular bottom wall 141. The annular bottom wall 141 and the side wall 143 together form a receiving cavity 144. The annular bottom wall 141 is provided with a through hole 142. The outer diameter of the positive electrode current collector 14 is smaller than the inner diameter of the negative electrode cover 12.

[0069] The positive electrode sheet 15 is received in the receiving cavity 144 of the positive current collector 14 and contacts the positive electrode cover 11 through the through hole 142. During battery assembly, the positive electrode sheet 15 is placed inside the positive current collector 14 to form the positive electrode assembly 100.

[0070] The negative electrode sheet 16 is housed in the inner cavity of the negative electrode cover 12 . During battery assembly, the negative electrode sheet 16 is placed inside the negative electrode cover 12 to form a negative electrode assembly 200 .

[0071] The diaphragm 17 is disposed between the positive electrode sheet 15 and the negative electrode sheet 16 to separate the positive electrode sheet 15 and the negative electrode sheet 16 . The projection of the negative electrode sheet 16 on the diaphragm 17 can roughly overlap with the projection of the positive electrode sheet 15 on the diaphragm 17 .

[0072] The electrolyte is filled in the button battery 1. After the electrolyte is injected, the internal structures such as the negative electrode sheet and the positive electrode sheet are immersed in the electrolyte. The charged ions in the positive electrode sheet and the negative electrode sheet are connected by current through the electrolyte.

[0073] refer to Figure 1 、 Figure 2 and Figure 5 The button battery 1 also includes a gasket assembly 20, which includes a connected gasket 21 and a spring 22, wherein the length of the gasket 21 is set to L1, and the length of the spring 22 is set to L2, L1>L2, the gasket 21 and the spring 22 are cross-connected, and the two ends of the gasket 21 are connected to the positive electrode collector. The gasket assembly 20 also includes a protrusion structure 23, which passes through the through hole of the positive electrode collector and is fixed on the positive electrode sheet. The protrusion structure 23 can be set on the gasket 21, or the protrusion structure 23 can be set on the spring 22, or the protrusion structure 23 can be set on both the spring 22 and the gasket 21. In the button battery, the positive electrode sheet is set to a compacted powder structure, and the protrusion structure 23 can be directly embedded in the positive electrode sheet 15.

[0074] By adding a gasket assembly 20 to the button battery 1, the gasket assembly 20 is connected to the positive electrode cover 11, and the gasket assembly 20 includes a gasket 21 and a spring 22 that are cross-connected to each other, wherein the length L1 of the gasket 21 is greater than the length L2 of the spring 22, so that both ends of the gasket 21 are connected to the positive electrode collector 14, and the spring 22 is located in the positive electrode collector 14. The protruding structure 23 arranged on the gasket 21 and / or the spring 22 is further fixed in the positive electrode sheet 15. Therefore, when the positive electrode cover 11 bulges outward, the gasket assembly 20 can further maintain the contact connection between the positive electrode cover 11 and the positive electrode sheet 15 and the positive electrode collector 14, thereby improving the stability of the internal structure of the button battery 1.

[0075] refer to Figure 1 、 Figure 5 、 Figure 6a as well as Figure 7aThe gasket 21 includes a gasket base 211 and a gasket boss 212 protruding from the gasket base 211. The gasket boss 212 and the gasket base 211 define a gasket receiving cavity 213. The gasket receiving cavity 213 is configured to receive a portion of the spring 22, so that a stable connection structure can be formed between the spring 22 and the gasket 21. It is understandable that if the spring 22 is directly connected to the gasket base 211 of the gasket 21, the spring base 221 will protrude from the gasket base 211. When the gasket 21 is connected to the positive electrode current collector 14, the spring 22 located inside the current collector 14 needs to be completely embedded in the positive electrode sheet 15, which greatly increases the difficulty of assembling the gasket assembly 20 and the positive electrode assembly 100. Therefore, a gasket boss 212 is provided on the gasket 21, which is protruding relative to its gasket base 211. The gasket boss 212 and the gasket base 211 define a gasket receiving cavity 213, and the spring 22 is placed in the gasket receiving cavity 213, so that the gasket base 211 and the spring base 221 can be located in the same plane, thereby greatly reducing the difficulty of assembly between the gasket assembly 20 and the positive electrode assembly 100.

[0076] In other examples, such as Figure 7d As shown, the elastic piece 22 includes an elastic piece base 221 and an elastic piece boss 223 protruding relative to the elastic piece base 221 . The elastic piece boss 223 and the elastic piece base define an elastic piece receiving cavity 224 , which is configured to receive a portion of the gasket 21 .

[0077] Continue to refer Figure 6a 、 Figure 6b 、 Figure 6c 、 Figure 7a 、 Figure 7b and Figure 7c , the thickness of the spring piece 22 is set to t1, the height of the gasket boss 212 is set to H1, H1≥t1; and / or, the width of the spring piece 22 is set to w1, the width of the gasket boss 212 is set to w2, w2=(1.05~1.3)*w1.

[0078] Through research, the inventors discovered that when the height H1 of the gasket boss 212 and the thickness t1 of the spring 22 satisfy the relationship: H1 ≥ t1, the spring 22 can be completely contained within the gasket receiving cavity 213 defined by the gasket boss 212 along its thickness direction. If the height H1 of the gasket boss 212 and the thickness t1 of the spring 22 satisfy the relationship: H1 < t1, at least a portion of the spring 22 protrudes relative to the gasket base 211 of the gasket 21 along its thickness direction, resulting in the gasket assembly 20 occupying more space within the button battery 1.

[0079] Through research, the inventors discovered that only when the width w2 of the gasket boss 212 and the width w1 of the spring clip 22 satisfy the following relationship: w2 = (1.05-1.3) w1, can the spring clip 22 be completely accommodated in the gasket receiving cavity 213 defined by the gasket boss 212 along its width direction, and sufficient assembly margin is formed between the spring clip 22 and the gasket boss 212. If the width w2 of the gasket boss 212 is less than 1.05 w1, when both the spring clip 22 and the gasket 21 are made of hard materials, a portion of the spring clip 22 will not be assembled into the gasket receiving cavity 213 defined by the gasket boss 212. If the width w2 of the gasket boss 212 is greater than 1.3 w1, the assembly gap between the spring clip 22 and the gasket boss 212 will be too large, thereby wasting the internal space of the button battery 1.

[0080] Similarly, if a spring piece boss 223 is provided on the spring piece 22, a spring piece receiving cavity 224 is defined between the spring piece boss 223 and the spring piece base 221, and a portion of the gasket 21 is received in the spring piece receiving cavity 224, then correspondingly, the thickness of the gasket 21 is set to t2, and the height of the spring piece boss 223 is not less than the thickness t2 of the gasket 21; and / or, the width of the gasket 21 is set to w3, and the ratio between the width of the spring piece boss 223 and the width of the gasket is in the range of (1.05 to 1.3).

[0081] If the height of the spring tab boss 223 and the thickness t2 of the gasket 21 cannot meet the above-mentioned size requirements, it will cause at least a portion of the gasket 21 to protrude relative to the spring tab base 221 of the spring tab 22 along its thickness direction, thereby causing the gasket assembly 20 to occupy more space inside the button battery 1.

[0082] If the size ratio between the height of the spring boss 223 and the width w3 of the gasket 21 is outside 1.05~1.3, the gasket will not be able to be assembled into the spring receiving cavity 224 defined by the spring boss 223, or the assembly gap between the gasket and the spring boss 223 is too large, thereby causing waste of the internal space of the button battery 1.

[0083] Continue to refer Figure 7c, the thickness t1 of the shrapnel 22 satisfies: 0.05mm≤t1≤0.30mm. In a specific implementation, the thickness t1 of the shrapnel 22 can be 0.05mm, 0.1mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, or a value between any two of the above values, or a range between any two of the above values. The inventors found through research that when the thickness t1 of the shrapnel 22 is less than 0.05mm, the overall strength of the shrapnel 22 is insufficient, and thus the shrapnel 22 cannot be stably embedded in the positive electrode sheet. When the thickness t1 of the shrapnel 22 is greater than 0.30mm, the overall size of the shrapnel 22 will be larger, and thus the gasket assembly will occupy more internal space of the button battery. The inventors found through further research that in a preferred implementation, the thickness t1 of the shrapnel 22 is set to 0.10mm~0.20mm, so that the shrapnel 22 can simultaneously meet the optimization between its strength and size ratio.

[0084] Continue to refer Figure 6c , the thickness t2 of the gasket 21 satisfies: 0.05mm≤t2≤0.30mm. In a specific implementation, the thickness t2 of the gasket 21 can be 0.05mm, 0.1mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, or a value between any two of the above values, or a range between any two of the above values. The inventors found through research that when the thickness t2 of the gasket 21 is less than 0.05mm, the overall strength of the gasket 21 is insufficient, and thus the gasket 21 cannot be stably embedded in the positive electrode sheet. When the thickness t2 of the gasket 21 is greater than 0.30mm, the overall size of the gasket 21 will be larger, and thus the gasket assembly will occupy more internal space of the button battery. The inventors found through further research that in a preferred implementation, the thickness t2 of the gasket 21 is set to 0.10mm~0.20mm, so that the gasket 21 can simultaneously meet the optimization between its strength and size ratio.

[0085] The thickness t2 of the gasket 21 and the thickness t1 of the spring 22 can be set to be different, as long as they are within the specified size range. Through further research, it was found that in a preferred embodiment, the thickness t2 of the gasket 21 and the thickness t1 of the spring 22 are set to be the same. This ensures that the strength of the gasket assembly 20 formed by the gasket 21 and the spring 22 is uniform at all locations, which helps the entire assembly provide a stable connection between the positive electrode assembly and the positive electrode cap.

[0086] Materials suitable for making the gasket 21 or the spring 22 include stainless steel. Suitable stainless steel materials include at least one of SUS44, SUS304, SUS430, and SUS316. The gasket 21 and the spring 22 can be made of different stainless steel materials with similar performance. In a preferred embodiment, the gasket 21 and the spring 22 are both made of SUS430, so that the gasket 21 and the spring 22 themselves are magnetic, which facilitates the connection between the gasket 21 and the spring 22 by welding, reduces the welding difficulty between the two, and improves the stability of the welding. Furthermore, if the gasket 21 and the spring 22 are made of the same stainless steel material, it is beneficial to prevent the formation of a potential difference between the gasket 21 and the spring 22.

[0087] refer to Figure 8 The spring piece 22 is welded on the gasket 21 to form a gasket assembly. The number of first welding points 241 between the spring piece 22 and the gasket 21 is an even number. For example, the number of first welding points 241 can be two, four, six or eight. In a preferred embodiment, the number of first welding points is set to two.

[0088] Through research, the inventors have discovered that if the spring piece 22 and the gasket 21 are welded at a single point, or if the number of first weld points 241 between the spring piece 22 and the gasket 21 is an odd number greater than 1, the weld between the spring piece 22 and the gasket 21 may be loose, further leading to relative positional offset between the spring piece 22 and the gasket 21. If three-point or four-point welding is used between the spring piece 22 and the gasket 21, the cost of the welding process will be further increased, which is not conducive to improving production efficiency. Therefore, in a preferred embodiment, the number of weld points between the spring piece 22 and the gasket 21 is two.

[0089] Continue to refer Figure 8 The first region Q1 formed between the spring 22 and the gasket 21 is configured as a circular welding area. The distance between the two first welding points 241 is configured as the diameter of the first region Q1. The center of the circular welding area coincides with the center of the gasket assembly 20. The diameter of the first region Q1 is no greater than the width w1 of the spring 22 and is also less than the width w3 of the gasket 21.

[0090] The spring piece 22 and the gasket 21 form a circular welding area, the center of which coincides with the center of the gasket assembly 20, so that a stable weld is formed between the spring piece 22 and the gasket 21, and it is beneficial for the gasket assembly 20 to form a centrally symmetrical structure.

[0091] The diameter of the first region Q1 is set to be no greater than the width w1 of the spring piece 22, and the diameter of the first region Q1 is no greater than the width w3 of the gasket 21, so that the first region Q1 is basically located in the central intersection area between the spring piece 22 and the gasket 21, and the problem of asymmetry between the spring piece 22 and the gasket 21 about the center of the gasket assembly 20 will not occur after the spring piece 22 and the gasket 21 are welded.

[0092] Continue to refer Figure 2 、 Figure 5 、 Figure 7a as well as Figure 10 The protruding structure 23 includes a first flange 231 and a second flange 232 provided on the elastic sheet 22 , wherein the first flange 231 is located at one end of the elastic sheet 22 , and the second flange 232 is located at the other end of the elastic sheet 22 .

[0093] The first flange 231 and the second flange 232 are respectively embedded in the positive electrode sheet 15. Therefore, the distance between the first flange 231 and the second flange 232 is configured to determine the range of action of the positive electrode sheet 15 that can be restricted by the gasket assembly 20 as a whole. If the first flange 231 and the second flange 232 are located in the middle of the spring 22, the range of action of the positive electrode sheet 15 corresponding to the first flange 231 and the second flange 232 will be smaller, thereby weakening the gasket assembly 20's restriction of the positive electrode sheet 15.

[0094] Continue to refer Figure 7c The first flange 231 and the second flange 232 are symmetrically arranged about the center of the gasket assembly 20. The first flange 231 and the second flange 232 have the same protruding height relative to the spring plate base 221, and are both set to h1. In a preferred embodiment, the height h1 of the first flange 231 or the second flange 232 and the thickness t1 of the spring plate 22 satisfy: 2*t1≤h1≤10*t1.

[0095] In some examples, h1 can be 2t1, 3t1, 4t1, 5t1, 6t1, 7t1, 8t1, 9t1, 10t1, a value between any two of the above values, or a range between any two of the above values.

[0096] Through research, the inventors found that when the height of the first flange 231 or the height h1 of the second flange 232 satisfies: 2t1≤h1≤10t1, after the first flange 231 and the second flange 232 are embedded in the positive electrode sheet 15, the overall structure of the positive electrode sheet 15 will not be damaged by the first flange 231 or the second flange 232 to cause rotten sheets or powder loss, and the first flange 231 and the second flange 232 will not be deformed during the process of embedding the positive electrode sheet 15.

[0097] refer to Figure 10aIf the height of the first flange 231 or the height of the second flange 232 h1 is less than 2t, the depth of the first flange 231 or the second flange 232 embedded in the positive electrode sheet 15 is insufficient. When the positive electrode cover 11 bulges, the first flange 231 or the second flange 232 is easily separated from the positive electrode sheet 15, resulting in poor contact between the gasket assembly 20 as a whole and the positive electrode current collector 14.

[0098] refer to Figure 10b If the height of the first flange 231 or the height of the second flange 232 h1>10t, the first flange 231 and the second flange 232 need to be embedded deeper into the positive electrode sheet 15, so that during the process of embedding the first flange 231 or the second flange 232 into the positive electrode sheet 15, the gasket assembly 20 is easily deformed and the overall structure of the positive electrode sheet 15 is easily damaged.

[0099] Continue to refer Figure 9a The extended line of the outer section of the first flange 231 or the second flange 232 has the same included angle with the spring base 221 , both being set to θ1, and θ1 satisfies: 90°≤θ1≤150°.

[0100] In a specific embodiment, the first flange 231 or the second flange 232 is symmetrically arranged about the center of the gasket assembly 20. The angle formed by the extension line of the outer cross-section of the first flange 231 and the plane on which the spring base 221 is located is the same as the angle formed by the extension line of the outer cross-section of the second flange 232 and the plane on which the spring 22 is located, and both are set to θ1. θ1 must satisfy the following: 90°≤θ1≤150°. For example, θ1 can be 90°, 100°, 110°, 120°, 130°, 140°, 150°, or an angle between any two of the above angles, or a range between any two of the above angles.

[0101] Through research, the inventors found that when θ1 is less than 90°, the first flange 231 or the second flange 232 is difficult to embed into the positive electrode sheet 15. When θ1 is greater than 150°, the range corresponding to the embedding of the first flange 231 or the second flange 232 into the positive electrode sheet 15 is too large, which can easily damage the overall structure of the positive electrode sheet 15 and cause it to powder and fall off.

[0102] Continue to refer Figure 9a , the first flange 231 or the second flange 232 can be set to a straight edge inclined structure. Or, as Figure 9b As shown, the first flange 231 or the second flange 232 can also be configured as a wave-shaped inclined structure. Figure 9c As shown, the first flange 231 or the second flange 232 may also be configured as an inclined structure with a pointed structure at the end.

[0103] Continue to refer Figure 1 、 Figure 6a The raised structure 23 also includes a gasket boss 212 disposed on the gasket 21. The gasket boss 212 passes through the through-hole 142 and is embedded in the positive electrode sheet 15. The gasket boss 212 is approximately located at the center of the gasket base 211. The gasket boss 212 is protruded relative to the plane of the gasket base 211. The gasket boss 212 defines a gasket receiving cavity 213, which is used to accommodate at least a portion of the spring 22. The gasket boss 212 can be embedded in the positive electrode sheet 15, thereby providing a fixing function for the positive electrode sheet 15.

[0104] The gasket 21 and the spring piece 22 are welded to form a gasket assembly 20, and the gasket boss 212 forms a reinforcing rib structure on the spring piece 22, so that the gasket boss 212 has a high strength after being embedded in the positive electrode sheet 15. The gasket boss 212 and the spring piece 22 are combined to form a raised structure with high embedding strength, so that the above-mentioned raised structure can maintain strong contact with the positive electrode sheet 15, so when the positive electrode cover 11 bulges outward, it is not easy for the positive electrode cover 11 to separate from the positive electrode sheet 15, thereby causing poor contact between them.

[0105] Furthermore, if the gasket 21 and the spring 22 are configured as an integrated structure, the strength of the gasket boss 212 is relatively low, which is equivalent to not accommodating the spring within the gasket receiving cavity 213 defined by the gasket boss 212. Therefore, when the height H1 of the gasket boss 212 is relatively high, the gasket boss 212 may be easily deformed when embedded in the positive electrode sheet 15. When the height H1 of the gasket boss 212 is relatively low, although the strength of the gasket boss 212 is increased, the gasket boss 212 may not be embedded in the positive electrode sheet 15, or the gasket boss 212 may not be embedded deeply enough in the positive electrode sheet 15, thereby failing to provide effective fixing.

[0106] refer to Figure 11 The orthographic projection of the gasket assembly 20 on the positive electrode cap 11 is arranged in a cross shape, wherein the orthographic projections of the gasket 21 and the spring 22 on the positive electrode cap 11 are both arranged in a straight line shape. The gasket assembly 20 and the positive electrode cap 11 are both arranged in a centrosymmetrical structure, and the center of the gasket assembly 20 substantially coincides with the center of the positive electrode cap 11.

[0107] By setting the gasket assembly 20 into a cross-shaped structure, in which the positive projections of the gasket 21 and the spring 22 on the positive electrode cover 11 are both set to a straight line, it is beneficial for the two ends of the longer gasket 21 in the gasket assembly 20 to be connected to the positive electrode collector 14, and the shorter spring 22 in the gasket assembly 20 is located inside the positive electrode collector 14.

[0108] The cross-shaped structure of the gasket assembly 20 can be a regular cross-shaped structure, such as Figure 11 The cross-shaped structure of the gasket assembly 20 can also be an irregular cross-shaped structure, such as Figure 12a As shown, the two ends of the gasket 21 are set to arc-shaped structures. Or, as Figure 12b As shown, the gasket base 211 includes two parts of the gasket base 211 located on both sides of the gasket boss 212, and the two parts of the gasket base 211 are both configured as fan-shaped structures.

[0109] refer to Figure 11 、 Figure 13 and Figure 14 The gasket assembly 20 is welded on the positive electrode cover 11. The gasket assembly 20 and the positive electrode cover 11 are both configured as a centrally symmetrical structure, and the concentricity of the gasket assembly 20 and the positive electrode cover 11 is not greater than 0.3 mm.

[0110] During the welding process of the gasket assembly 20 and the positive electrode cap 11, it is necessary to control the concentricity between the gasket assembly 20 and the positive electrode cap 11 to be no greater than 0.3 mm. In a preferred embodiment, the concentricity between the gasket assembly 20 and the positive electrode cap 11 is no greater than 0.1 mm. The inventors have found through research that if the concentricity between the positive electrode cap 11 and the gasket assembly 20 is greater than 0.3 mm, it will cause serious misalignment between the gasket assembly 20 and the positive electrode cap 11, and further cause serious misalignment between the gasket assembly 20 and the current collector 14, which in turn will lead to a decrease in the current collecting effect of the positive electrode current collector 14, further affecting the electrical performance of the button cell 1.

[0111] Continue to refer Figure 11 The number of second welding points 242 formed by welding the gasket assembly 20 and the positive electrode cover 11 is at least two, and the at least two second welding points 242 are symmetrically arranged about the center of the gasket assembly 20.

[0112] Through research, the inventors have discovered that during the welding process of the gasket assembly 20 to the positive electrode cap 11, the number of second weld points 242 formed by welding the gasket assembly 20 and the positive electrode cap 11 is preferably two. Two second weld points 242 help improve the weld strength between the gasket assembly 20 and the positive electrode cap 11. If the number of second weld points 242 formed by welding the gasket assembly 20 and the positive electrode cap 11 is only one, the gasket assembly 20 is likely to be misaligned with respect to the positive electrode cap 11 and warp. If the number of second weld points 242 formed by welding the gasket assembly 20 and the positive electrode cap 11 is greater than two, the welding process between the gasket assembly 20 and the positive electrode cap 11 is complicated and the welding cost is increased.

[0113] Continue to refer Figure 11 and Figure 15 By optimizing the position of the welding area between the gasket assembly 20 and the positive electrode cover 11, the stability of the button battery 1 can be further improved.

[0114] The base of the gasket assembly 20 available for welding is divided into five areas, namely the first area Q1, the first part Q2a of the second area, the second part Q2b of the second area, the first part Q3a of the third area, and the second part Q3b of the third area. The first area Q1 is set as the welding area of ​​the gasket 21 and the spring 22. The first part Q2a of the second area and the second part Q2b of the second area are set on both sides of the first area Q1 and are located on the gasket 21. The first part Q3a of the third area and the second part Q3b of the third area are set on both sides of the first area Q1 and are located on the spring 22.

[0115] The second welding point 242 between the gasket assembly 20 and the positive electrode cover 11 can be set above the first part Q2a of the second area and the second part Q2b of the second area, and the second welding point 242 between the gasket assembly 20 and the positive electrode cover 11 is located outside the first part Q3a of the third area and the second part Q3b of the third area.

[0116] The inventors discovered that if the second weld point 242 between the gasket assembly 20 and the positive electrode cap 11 is located above the first portion Q3a and the second portion Q3b of the third region, the gasket assembly 20 will lose its elasticity. When the positive electrode cap 11 swells, the first and second flanges 231, 232 of the gasket assembly 20 are welded to the positive electrode cap 11, causing the first and second flanges 231, 232 to separate from the positive electrode sheet 15. Furthermore, the gasket assembly 20 and the positive electrode sheet 15 lose contact, rendering the first and second flanges 231, 232 ineffective in retaining the positive electrode sheet 15. It should be noted that because the first region Q1 is configured as the welding area for the gasket 21 and the spring 22, the first region Q1 can no longer serve as the welding area between the gasket assembly 20 and the positive electrode cap 11.

[0117] Continue to refer Figure 7b 、 Figure 11 and Figure 15 The distance between at least two second welding points 242 is set to d1, and d1 satisfies: 0.3*L1+0.7*w1≤d1≤0.9*L1+0.1*w1. Wherein L1 is set to the length of the gasket 21, and w1 is set to the width of the spring 22.

[0118] Through research, the inventors found that in order to ensure the consistency of performance after welding the gasket assembly 20 and the positive electrode cover 11, it is preferred to set two second welding points 242 between the gasket assembly 20 and the positive electrode cover 11, and the two second welding points 242 are symmetrically distributed about the center of the gasket assembly 20. Furthermore, in order to ensure that the button battery is used at high temperatures, when the positive electrode cover 11 bulges, the gasket assembly 20 is connected to the positive electrode assembly, and the gasket assembly 20 and the positive electrode cover 11 are connected without a non-contact gap between the two. Therefore, the distance d1 between the two second welding points 242 is required to satisfy: 0.3*L1+0.7*w1≤d1≤0.9*L1+0.1*w1, where Figure 15 、 Figure 16a and Figure 16b As shown, L3=0.3*L1+0.7*w1, L4=0.9*L1+0.1*w1, L3≤d1≤L4, when the distance d1 between the two second welding points 242 is too large, that is, d1 is greater than 0.9L1+0.1w1, the position of the second welding point 242 is set close to the edge of the gasket assembly 20, and the welding strength between the gasket assembly 20 and the positive electrode cover 11 is low. When the positive electrode cover 11 bulges, the gasket assembly 20 is easily separated from the positive electrode cover 11, thereby causing the connection between the gasket assembly 20 and the positive electrode cover 11 to fail. Figure 16a and Figure 16b As shown, when the distance d1 between the two second welding points 242 is too small, that is, d1 is less than 0.3*L1+0.7*w1, the position of the second welding point 242 is set close to the center of the circle of the positive cover 11. When the positive cover 11 bulges, the gasket assembly 20 bulges along with the positive cover 11, which makes it easy for the gasket assembly 20 to separate from the positive electrode sheet 15. The limiting effect of the gasket assembly 20 on the positive electrode sheet 15 fails, which leads to poor contact between the positive electrode sheet 15 and the positive cover 11.

[0119] refer to Figure 15 、 Figure 17 and Figure 18 The positive electrode current collector 14 includes an annular bottom wall 141, which defines a through hole 142. The two ends of the gasket 21 are connected to the annular bottom wall 141, so that the two ends of the gasket 21 are pressed between the annular bottom wall 141 and the positive electrode cover 11. The positive electrode sheet 15 accommodated in the positive electrode cover 11 is in contact with the positive electrode cover 11 through the through hole 142.

[0120] refer to Figures 17 to 21 as well as Figure 22aThe diameter of the circumscribed circle corresponding to the edge of the gasket 21 is set to D1, the diameter of the circumscribed circle corresponding to the edge of the elastic sheet 22 is set to D2, the gasket 21 includes a first end 2141 and a second end 2142 arranged opposite to each other, the first end 2141 includes two first endpoints 2143, and the angle between the two first endpoints 2143 and the line connecting the center of the gasket assembly 20 is 2θ2, the diameter of the through hole 142 of the positive current collector 14 is set to D3, the outer diameter of the annular bottom wall 141 of the positive current collector 14 is set to D4, the thickness of the positive current collector 14 is set to t3, and the length L1 of the gasket 21 satisfies: L1 = D1*cosθ2, and 1.02*D3*cosθ2≤L1≤0.98*(D4-2t3)*cosθ2.

[0121] In order to ensure that the two ends of the gasket 21 always maintain contact with the annular bottom wall 141 of the positive current collector 14, and after the button battery 1 is sealed, the two ends of the gasket 21 are still overlapped on the annular bottom wall 141 of the positive current collector 14, the inventors have found through research that, in a preferred implementation, 1.02D3*cosθ2≤L1≤0.98*(D4-2t3)*cosθ2.

[0122] Further references Figure 22b As shown, if the length of the gasket 21 is set to L1a, L1a>0.98*(D4-2t3)*cosθ2, at least a portion of the area where one end of the gasket 21 is located exceeds the area Q4 where the annular bottom wall 141 of the positive electrode current collector 14 is located, as shown in FIG. Figure 22b As shown in the area 21a, the other end of the gasket 21 does not contact the area Q4 where the annular bottom wall 141 is located. Figure 22b As shown in FIG21b, during the sealing process of the button battery 1, since the edge strength of the positive electrode current collector 14 is greater than the strength of the plane where the annular bottom wall 141 of the positive electrode current collector 14 is located, the height corresponding to the exceeding area 21a where the gasket 21 exceeds the edge of the positive electrode current collector 14 is greater than the height corresponding to the non-exceeding area 21b where the gasket 21 does not exceed the edge of the positive electrode current collector 14, a height difference occurs inside the positive electrode current collector 14, resulting in a poor current collecting effect of the positive electrode current collector 14.

[0123] Further references Figure 22c As shown, if the length of the gasket 21 is set to L1b, L1b<1.02*D3*cosθ2, the area where one end of the gasket 21 is located is located in the area where the through hole 142 of the positive electrode current collector 14 is located, as shown in FIG. Figure 22c As shown in the figure, the other end of the gasket 21 is located in the plane area Q4 where the annular bottom wall 141 of the positive electrode current collector 14 is located. Figure 22cAs shown in the non-exceeded area 21d, during the sealing process of the button battery 1, the height corresponding to the excess area 21c where one end of the gasket 21 is located at the through hole 142 of the positive current collector 14 is greater than the height corresponding to the non-exceeded area 21d where the other end of the gasket 21 is located at the plane where the annular bottom wall 141 of the positive current collector 14 is located, resulting in a height difference inside the positive current collector 14, which causes the current collecting effect of the positive current collector 14 to deteriorate.

[0124] Continue to refer Figures 19 to 21 The spring piece 22 includes a third end 2221 and a fourth end 2222. The third end 2221 includes two second endpoints 2223. The angle between the two second endpoints 2223 and the line connecting the center of the gasket assembly 20 is 2θ3. The length L2 of the spring piece 22 satisfies: 1.5*w3≤L2≤0.98*D3*cosθ3, where w3 is the width of the gasket 21 and D3 is the inner diameter of the through hole 142.

[0125] When the button battery 1 is packaged, the first flange 231 and the second flange 232 of the spring 22 are embedded in the positive electrode sheet 15 to limit the positive electrode sheet 15. In order to ensure that when there is a position deviation between the gasket assembly 20 and the positive electrode collector 14 or the positive electrode cover 11 bulges outward, the first flange 231 and the second flange 232 of the spring 22 can still be embedded in the positive electrode sheet 15 and maintain an elastic connection with the positive electrode sheet 15, the inventors have found through research that the length L2 of the spring 22 needs to meet the following requirements: 1.5*w3≤L2≤0.98*D3*cosθ3.

[0126] If the length L2 of the spring clip 22 is greater than 0.98*D3*cosθ3, the relative position deviation between the gasket assembly 20 and the positive electrode current collector 14 is large, resulting in the first flange 231 and / or the second flange 232 being unable to be embedded in the positive electrode sheet 15; if the length L2 of the spring clip 22 is less than 1.5w3, when the positive electrode cover 11 bulges outward, the first flange 231 and / or the second flange 232 of the spring clip 22 will move outward with the positive electrode cover 11, thereby causing the first flange 231 and / or the second flange 232 to detach from the positive electrode sheet 15, the gasket assembly 20 loses its elastic limiting effect on the positive electrode current collector 14, and poor contact occurs between the gasket assembly 20 and the positive electrode current collector 14.

[0127] This application also provides a method for preparing a gasket assembly 20 for a button battery 1, referring to Figure 23a 、 Figure 23b and Figure 23c , the preparation method of the gasket assembly 20 includes:

[0128] The stamping process is used to prepare a plurality of connected gasket combinations in the form of strips, and adjacent gaskets are connected by connecting edges, such as Figure 23a As shown;

[0129] The stamping process is used to prepare a plurality of connected spring pieces in a strip shape, and the adjacent spring pieces are connected by connecting the edges of the materials, such as Figure 23b As shown;

[0130] After adjusting the spring assembly and the gasket assembly until their centers coincide, use laser welding equipment to weld the spring assembly and the gasket assembly together to form multiple connected gasket assemblies. Adjacent gasket assemblies are connected by connecting the edges of the materials, such as Figure 23c shown.

[0131] Compared with the preparation method of welding a single gasket and a single spring piece one by one to form the gasket assembly 20 , the preparation method of the gasket assembly 20 can effectively improve the production efficiency of the gasket assembly 20 and the cost of the assembly process.

[0132] An embodiment of the present application further provides a button battery assembly method, the button battery assembly method comprising:

[0133] Step 1: Combine the above-mentioned gasket components and cut them into a single gasket component;

[0134] Step 2: Adjust the relative position between the gasket assembly and the positive electrode cover = Then, weld the gasket assembly and the positive electrode cover together to form a positive electrode cover assembly, such as Figure 14 As shown;

[0135] Step 3: Place the positive electrode sheet into the positive electrode current collector to form a positive electrode assembly;

[0136] Step 4: Place the negative electrode sheet into the negative electrode cover to form a negative electrode cover assembly;

[0137] Step 5: Place the separator and the positive electrode assembly in the negative electrode cover assembly in sequence to form an assembly;

[0138] Step 6: Injecting electrolyte into the above assembly;

[0139] Step 7: Cover the end of the above assembly with a positive electrode cap assembly, seal it, and form a button battery.

[0140] It should be noted that the order of the steps in the above preparation method can be adjusted according to the requirements of the actual assembly process and is not limited to the order described in the above embodiment.

[0141] The present application further provides a specific embodiment 1 and comparative examples 1 to 4. By conducting a high-temperature storage experiment on the button battery 1 provided in embodiment 1 and comparative examples 1 to 4, the changes in the internal resistance of the batteries of embodiment 1, comparative example 1, comparative example 2, comparative example 3 and comparative example 4 under high-temperature environment are further verified.

[0142] Example 1

[0143] refer to Figure 24a The button cell provided in Example 1 includes a gasket assembly 20, the structure of which is as follows: Figure 5 As shown, the gasket base and the spring base both adopt a straight-line structure, the length of the gasket L1 = 0.91*(D4-2t3)*cosθ2, the length of the spring L2 = 0.72*D3*cosθ3, the thickness t2 of the gasket or the thickness t1 of the spring satisfies: t1 = t2 = 0.10, the angle θ1 of the first flange or the second flange satisfies: θ1 = 120°, and the height h1 of the first flange or the second flange satisfies: h1 = 4t1.

[0144] Comparative Example 1

[0145] refer to Figure 24c The button cell provided in Comparative Example 1 includes a gasket assembly 20, the structure of which is as follows: Figure 5 As shown, the gasket base and the spring base both adopt a straight-line structure, the length of the gasket L1 = 0.91*(D4-2t3)*cosθ2, the length of the spring L2 = 0.72*D3*cosθ3, the thickness t2 of the gasket or the thickness t1 of the spring satisfies: t1 = t2 = 0.10, the angle θ1 of the first flange or the second flange satisfies: θ1 = 120°, and the height h1 of the first flange or the second flange satisfies: h1 = 10*t1.

[0146] Comparative Example 2

[0147] refer to Figure 24b The button cell provided in Comparative Example 2 includes a gasket assembly 20, the structure of which is as follows: Figure 5 As shown, the gasket base and the spring base both adopt a straight-line structure, the length of the gasket L1 = 0.91*(D4-2t1)*cosθ2, the length of the spring L2 = 0.72*D3*cosθ3, the thickness t2 of the gasket or the thickness t1 of the spring satisfies: t1 = t2 = 0.10, the angle θ1 of the first flange or the second flange satisfies: θ1 = 120°, and the height h1 of the first flange or the second flange satisfies: h1 = 2t1.

[0148] Comparative Example 3

[0149] The button cell provided in Comparative Example 3 includes a gasket assembly 20, the structure of which is as follows: Figure 5As shown, the gasket base and the spring base both adopt a straight-line structure, the length of the gasket L1 = (D4-2t1)*cosθ2, the length of the spring L2 = 0.72*D3*cosθ3, the thickness t2 of the gasket or the thickness t1 of the spring satisfies: t1 = t2 = 0.10, the angle θ1 of the first flange or the second flange satisfies: θ1 = 120°, and the height h1 of the first flange or the second flange satisfies: h1 = 4t1.

[0150] Comparative Example 4

[0151] The button cell provided in Comparative Example 4 includes a gasket assembly 20, the structure of which is as follows: Figure 5 As shown, the gasket base and the spring base both adopt a straight-line structure, the length of the gasket L1 = 0.90*D3*cosθ2, the length of the spring L2 = 0.72*D3*cosθ3, the thickness t2 of the gasket or the thickness t1 of the spring satisfies: t1 = t2 = 0.10t, the angle θ1 of the first flange or the second flange satisfies: θ1 = 120°, and the height h1 of the second flange satisfies: h1 = 4t1.

[0152] High temperature storage test (internal resistance evaluation):

[0153] The button batteries provided in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 obtained in the above order were subjected to the high-temperature storage test described below to evaluate the change in internal resistance under high-temperature conditions.

[0154] Specifically, the internal resistance (Ω) between the positive electrode and the negative electrode of the button-type batteries obtained in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 was first measured using the same method, and the initial resistance (Ω) is shown in Table 1 below. Next, the button-type batteries of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 were stored in a high-temperature box with the internal temperature of the box set to 125° C. for one week. After one week of storage, the internal resistance (Ω) between the positive electrode and the negative electrode of the button-type batteries of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 was measured using the same method, and this value is used as the internal resistance (Ω) after one week of storage, and is shown in Table 1 below.

[0155] Table 1

[0156]

[0157] Evaluation results:

[0158] As shown in Table 1, comparing Example 1 with Comparative Example 1, the height h1 of the first or second flange of the gasket assembly of the button cell in Example 1 was set to 4t1, resulting in an initial internal resistance of 3.259Ω. The height h1 of the first or second flange of the gasket assembly of the button cell in Comparative Example 1 was set to 10t1, resulting in a significantly higher initial internal resistance for the button cell in Example 1 than for the button cell in Comparative Example 1. After disassembly and analysis of the batteries, the initial internal resistance of the button cell in Comparative Example 1 was significantly higher than that of the button cell in Example 1. This is because, after the first or second flange of the button cell in Comparative Example 1 was inserted into the positive electrode sheet, the first or second flange of the button cell deformed and the positive electrode sheet shed powder, resulting in poor internal contact. Consequently, the initial internal resistance of the button cell in Comparative Example 1 was significantly higher than that of the button cell in Example 1.

[0159] As shown in Table 1, Example 1 and Comparative Example 2 are compared. The height of the first flange or the second flange of the gasket assembly of the button battery of Example 1 is h1 and is set to 4t1. The height of the first flange or the second flange of the gasket assembly of the button battery of Comparative Example 2 is h1 and is set to 2t1. The initial internal resistance of the button battery of Example 1 is not much different from the initial internal resistance of the button battery of Comparative Example 2. However, after being stored at a high temperature of 125°C for one week, the internal resistance increase rate of the button battery of Comparative Example 2 is much higher than the internal resistance increase rate of the button battery of Example 1. After image analysis of the button battery CT (computed tomography), it was found that a portion of the first flange or the second flange of the gasket assembly of the button battery of Comparative Example 2 was detached from the positive electrode sheet, which resulted in poor internal contact of the button battery under high-temperature storage.

[0160] The results of the embodiments and comparative examples described above show that by setting the height parameter h1 of the first flange or the second flange of the gasket assembly of the button battery to the condition specified in the present invention, the internal contact of the battery can be increased, thereby achieving the purpose of improving the battery stability, and effectively preventing poor internal contact caused by the bulging of the positive electrode cover in a high temperature environment. Therefore, the characteristics of the button battery will not deteriorate, and the battery electrical performance stability will be higher.

[0161] Comparing Example 1 with Comparative Example 3, the length of the gasket of the gasket assembly of the button battery of Example 1 is set to 0.91*(D4-2t1)*cosθ2, and the length of the gasket of the gasket assembly of the button battery of Comparative Example 3 is set to (D4-2t1)*cosθ2. It can be seen from the data in Table 1 that when the gasket length is too long, the initial internal resistance of the button battery of Comparative Example 3 is close to the initial internal resistance of the button battery of Example 1, but after being stored at a high temperature of 125°C for 1 week, the internal resistance increase rate of the button battery of Comparative Example 3 is much greater than the internal resistance increase rate of the button battery of Example 1. From the appearance of the button cells of the comparative example 3 and the button cells of Example 1, it was found that the positive electrode cover of the button cell of comparative example 3 had obvious pits and bulges. When the button cells of comparative example 3 and the button cells of Example 1 were placed under CT scanning, it was found that the length of the gasket at the bulge position of the positive electrode cover of the button cell of comparative example 3 exceeded the positive electrode collector. Therefore, it can be analyzed that: since part of the length of the gasket exceeded the positive electrode collector, the gasket and the positive electrode collector formed a rib-like structure, resulting in different strengths of the gasket and the positive electrode collector at different positions when the battery was sealed, which in turn caused the positive electrode cover of the battery to bulge outward, and the internal resistance of the button cell was unstable and increased after high-temperature storage.

[0162] Comparing Example 1 with Comparative Example 4, the length of the gasket of the gasket assembly of the button battery of Example 1 is set to 0.91*(D4-2t1)*cosθ2, and the length of the gasket of the gasket assembly of the button battery of Comparative Example 4 is set to 0.90*D3*cosθ2. It can be seen from the data in Table 1 that when the gasket length is too small, although the initial internal resistance of the button battery of Comparative Example 4 is close to the initial internal resistance of the button battery of Example 1, after being stored at a high temperature of 125°C for one week, the internal resistance increase rate of the button battery of Comparative Example 4 is as high as 216%, which is much greater than the internal resistance increase rate of the button battery of Example 1. First, after observing the button battery CT of Comparative Example 4, it was found that one side of the gasket was not placed in the area Q4 where the annular bottom wall of the positive electrode collector is located; at the outer bulge of the positive electrode cover, there is a slight gap between the gasket and the positive electrode collector. After disassembling the battery, it was found that one side of the gasket was not placed in area Q4 where the annular bottom wall of the positive electrode collector was located, and the gasket assembly was partially detached from the positive electrode sheet, resulting in poor contact and increased internal resistance.

[0163] The above is a detailed introduction to the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, based on the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A button battery, characterized in that: include: positive electrode cap; A positive electrode current collector is arranged inside the positive electrode cover, and a through hole is provided on the bottom wall of the positive electrode current collector; A positive electrode sheet, housed inside the positive electrode current collector; A gasket assembly is connected to the positive electrode cover, and the gasket assembly includes a gasket and a spring sheet arranged separately. The length of the gasket is L1, and the length of the spring sheet is L2, L1>L2. The gasket and the spring sheet are cross-connected, and the spring sheet is located inside the positive electrode current collector. A protrusion structure is provided on the gasket and / or the spring sheet, and the protrusion structure passes through the through hole and is fixed to the positive electrode sheet.

2. The button battery according to claim 1, characterized in that The gasket includes a gasket base and a gasket boss protruding relative to the gasket base, wherein the gasket boss and the gasket base define a gasket receiving cavity, and the gasket receiving cavity is configured to receive a portion of the elastic sheet; Alternatively, the elastic sheet includes an elastic sheet base and an elastic sheet boss protruding relative to the elastic sheet base, the elastic sheet boss and the elastic sheet base define an elastic sheet receiving cavity, and the elastic sheet receiving cavity is configured to receive a portion of the gasket.

3. The button battery according to claim 2, characterized in that The thickness of the spring sheet is set to t1, the height of the gasket boss is set to H1, and the height H1 of the gasket boss is set to be no less than the thickness t1 of the spring sheet; and / or the width of the spring sheet is set to w1, the width of the gasket boss is set to w2, and the ratio between the width w2 of the gasket boss and the width w1 of the spring sheet is (1.05-1.3):1; Alternatively, the thickness of the gasket is set to t2, and the height of the spring boss is set to not less than the thickness t2 of the gasket; and / or, the width of the gasket is set to w3, and the ratio between the width of the spring boss and the width w3 of the gasket is (1.05~1.3):

1.

4. The button battery according to claim 3, characterized in that The thickness t1 of the spring sheet satisfies: 0.05 mm ≤ t1 ≤ 0.30 mm; and / or, The thickness of the gasket satisfies t2: 0.05≤t2≤0.30mm; and / or, The thickness t1 of the elastic sheet and the thickness t2 of the gasket are set to be the same.

5. The button battery according to claim 3, characterized in that The spring piece is welded to the gasket, and the number of first welding points between the spring piece and the gasket is an even number.

6. The button battery according to claim 5, characterized in that The spring piece is welded to the gasket in a circular welding area. The diameter of the circular welding area is smaller than the width w1 of the spring piece, and the diameter of the circular welding area is smaller than the width w3 of the gasket.

7. The button battery according to claim 3, characterized in that The protruding structure includes a first flange and a second flange arranged on the elastic sheet, the first flange is located at one end of the elastic sheet, and the second flange is located at the other end of the elastic sheet. The first flange and the second flange pass through the through hole and are embedded in the positive electrode sheet.

8. The button battery according to claim 7, characterized in that The height of the first flange or the second flange is set to h1, 2*t1<h1<10*t1; and / or, An angle formed by an extension line of an outer sectional surface of the first flange or the second flange and a plane where the elastic sheet base is located is θ1, and θ1 is set to be 90° to 150°.

9. The button battery according to claim 7, characterized in that: The protruding structure further includes the gasket boss, which passes through the through hole and is embedded in the positive electrode sheet.

10. The button battery according to any one of claims 1 to 9, characterized in that: The orthographic projection of the gasket assembly on the positive electrode cover is arranged in a cross shape, wherein the orthographic projections of the spring and the gasket on the positive electrode cover are both arranged in a straight line shape.

11. The button battery according to claim 10, characterized in that The spring piece and the gasket are made of the same stainless steel material.

12. The button battery according to claim 2, characterized in that The gasket assembly is welded to the positive electrode cover. The gasket assembly and the positive electrode cover are both configured as a centrally symmetrical structure, and the concentricity of the gasket assembly and the positive electrode cover is not greater than 0.3 mm.

13. The button battery according to claim 12, characterized in that There are at least two second welding points between the gasket assembly and the positive electrode cover, and the at least two second welding points are symmetrically arranged about the center of the gasket assembly.

14. The button battery according to claim 13, characterized in that The gasket assembly includes a first area formed by welding the gasket and the elastic sheet, a second area located on the gasket, and a third area located on the elastic sheet, the second area including a second area first portion and a second area second portion located on opposite sides of the first area, and the third area including a third area first portion and a third area second portion located on opposite sides of the first area; At least two of the second welding points are located within the first portion of the second region and the second portion of the second region; Furthermore, at least two of the second welding points are located outside the first portion of the third region and the second portion of the third region.

15. The button battery according to claim 14, characterized in that: The distance between the at least two second welding points is set to d1, 0.3*L1+0.7*w1≤d1≤0.9*L1+0.1*w1.

16. The button battery according to claim 1, characterized in that The positive electrode current collector includes an annular bottom wall, and both ends of the gasket are connected to the annular bottom wall.

17. The button battery according to claim 16, characterized in that The diameter of the circumscribed circle corresponding to the edge of the gasket is set to D1, the gasket includes a first end and a second end, the first end includes two first endpoints, the angle between the two first endpoints and the line connecting the center of the gasket is 2θ2, the diameter of the through hole of the positive current collector is set to D3, the diameter of the annular bottom wall of the positive current collector is set to D4, the thickness of the positive current collector is set to t3, and the length L1 of the gasket satisfies: L1 = D1*cosθ2, and 1.02*D3*cosθ2≤L1≤0.98*(D4-2t3)*cosθ2.

18. The button battery according to claim 17, characterized in that The spring piece includes a third end and a fourth end, the third end includes two second end points, the angle between the two second end points and the line connecting the center of the spring piece is 2θ3, and the length L2 of the spring piece satisfies: 1.5*w3≤L2≤0.98*D3*cosθ3.

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