A button lithium ion battery

Abstract

The present invention discloses a button-type lithium-ion battery, comprising a negative electrode shell, a positive electrode shell and a sealing ring. The negative electrode shell comprises a negative electrode shell wall, and the radial cross section of the negative electrode shell wall is configured as a first shape. The positive electrode shell is sleeved to the negative electrode shell, and comprises a positive electrode shell wall, the positive electrode shell wall is located outside the negative electrode shell wall, and the positive electrode shell wall comprises a pre-snap-fit ​​section, and the radial cross section of the pre-snap-fit ​​section is configured as a second shape. The sealing ring is at least partially located between the positive electrode shell wall and the negative electrode shell wall. The first shape and the second shape are not similar to each other, so that a gap can be formed between the pre-snap-fit ​​section and the sealing ring in a pre-installed state. According to the button-type lithium-ion battery of the present invention, a gap is left between the positive electrode shell and the sealing ring during pre-installation, so that the air in the battery can be discharged through the gap during vacuuming, which ensures that the battery is accurately fastened and positioned, and also ensures the vacuuming effect, improves the stability of automated production, and greatly improves production efficiency.

Description

Technical Field

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

[0002] Since the electrolysis reaction in button lithium batteries needs to be carried out in an air-tight environment, during the battery assembly process, the battery cavity after liquid injection needs to be vacuumed to remove the air in the cavity while leaving enough space for gas production in the subsequent processes (chemical composition, etc.).

[0003] However, in the actual automated production process, after the battery is filled with liquid, the caps must be pre-fastened to position the positive and negative electrode shell covers, and then sealed. Before sealing, the air inside the battery must be vacuumed. If the caps are too tight, the vacuuming may fail easily, and the internal gas may remain in the battery, causing the internal pressure to increase. If the caps are too loose, the positioning of the positive and negative electrode shell covers may fail easily, resulting in difficulties in automated production.

[0004] Therefore, a button-type lithium-ion battery is needed to at least partially solve the above problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In order to at least partially solve the above problems, the present invention provides a button-type lithium-ion battery, comprising:

[0007] A negative electrode casing, the negative electrode casing comprising a negative electrode casing wall, wherein a radial cross section of the negative electrode casing wall is configured as a first shape;

[0008] A positive electrode shell, the positive electrode shell is sleeved on the negative electrode shell, the positive electrode shell includes a positive electrode shell wall, the positive electrode shell wall is located outside the negative electrode shell wall, the positive electrode shell wall includes a pre-fastening fit segment, and the radial cross-section of the pre-fastening fit segment is configured as a second shape; and

[0009] A sealing ring, the sealing ring being at least partially located between the positive electrode shell wall and the negative electrode shell wall;

[0010] The first shape and the second shape are not similar to each other, so that in a pre-installed state, a gap can be formed between the pre-fastening section and the sealing ring.

[0011] Further, the first shape is a circle, and / or the second shape is an ellipse.

[0012] Furthermore, the eccentricity of the ellipse is 0.08-0.3.

[0013] Furthermore, the eccentricity of the ellipse is 0.135-0.178.

[0014] Further, the positive electrode shell includes a positive electrode shell bottom and a positive electrode shell wall extending from the periphery of the positive electrode shell bottom, and the positive electrode shell wall includes:

[0015] A fastening section, the fastening section is connected to the bottom of the positive electrode case, and in the installed state, the compression rate of the sealing ring at the fastening section is 30% to 70%;

[0016] a first transition section, the first transition section being connected to the fastening section, the first transition section being inclined outwardly;

[0017] the snap-fit ​​section connected to the transition section; and

[0018] A guide section is connected to the buckle-fit section, and the guide section is inclined outward.

[0019] Further, the negative electrode shell includes a negative electrode shell bottom and a negative electrode shell wall extending from the periphery of the negative electrode shell bottom, and the negative electrode shell wall includes:

[0020] A body segment connected to the bottom of the negative electrode shell;

[0021] a second transition section, the second transition section being connected to the body section, the second transition section being inclined outwardly;

[0022] An installation fitting section is connected to the second transition section, and the sum of the radial dimension of the installation fitting section and the thickness of the sealing ring located between the positive electrode shell wall and the negative electrode shell wall is greater than or equal to the radial dimension of the fastening section.

[0023] Furthermore, the sealing ring comprises:

[0024] A first vertical extension portion, wherein the first vertical extension portion is located on the inner side of the negative electrode shell wall;

[0025] a second vertical extension portion, the second vertical extension portion being located outside the negative electrode shell wall;

[0026] a transverse extension portion, the transverse extension portion being connected to ends of the first vertical extension portion and the second vertical extension portion, and the end of the negative electrode case wall being abutted against the transverse extension portion;

[0027] Wherein, the radial dimension of the second vertical extension portion gradually increases in a direction away from the lateral extension portion.

[0028] Further, the second vertical extension portion is inclined outwardly in a direction away from the lateral extension portion, and an inclination angle of the second vertical extension portion is less than or equal to 3°.

[0029] Furthermore, the radial cross-sectional shape of the pre-fastening fitting section has a major axis and a minor axis, the size of the major axis is greater than the sum of the radial size of the installation fitting section and the thickness of the second vertical extension portion, and the size of the minor axis is less than or equal to the sum of the radial size of the installation fitting section and the thickness of the second vertical extension portion.

[0030] Furthermore, the length of the pre-fastening section accounts for 25% to 45% of the length of the positive electrode shell wall.

[0031] Further, in the pre-installation state, the height of the pre-snap-fit ​​section corresponds to the height of the installation fitting section, and the gap is formed between the pre-snap-fit ​​section and the second vertical extension portion.

[0032] Furthermore, the positive electrode shell and the negative electrode shell form a receiving chamber, and the receiving chamber is provided with a battery cell and an electrolyte. In the installed state, the air pressure in the receiving chamber is lower than the external air pressure.

[0033] According to the button-type lithium-ion battery of the present invention, during pre-installation, the portion of the positive electrode shell near the end of the short axis is interference-fitted with the sealing ring, and a gap is left between the portion of the positive electrode shell near the end of the long axis and the sealing ring to form a vacuum channel, so that the air in the battery can be discharged through the channel during vacuumization, which ensures the accurate buckling and positioning of the battery while also ensuring the vacuumization effect, thereby improving the stability of automated production and greatly improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following drawings of the present invention are used to understand the present invention as part of the present invention. The embodiments of the present invention are shown in the drawings and the description thereof is used to explain the principle of the present invention.

[0035] In the attached figure:

[0036] Figure 1 It is a schematic structural diagram of a button-type lithium-ion battery in an installed and unsealed state according to a preferred embodiment of the present invention;

[0037] Figure 2 A schematic structural diagram of a negative electrode housing of a button-type lithium-ion battery according to a preferred embodiment of the present invention;

[0038] Figure 3 A schematic structural diagram of a positive electrode housing of a button-type lithium-ion battery according to a preferred embodiment of the present invention;

[0039] Figure 4 A schematic structural diagram of a sealing ring of a button-type lithium-ion battery according to a preferred embodiment of the present invention;

[0040] Figure 5 for Figure 3 Schematic diagram of the cross section along the CC direction;

[0041] Figure 6 A schematic diagram of the installation direction of a button-type lithium-ion battery according to a preferred embodiment of the present invention;

[0042] Figure 7 A schematic diagram of a button-type lithium-ion battery in a pre-installed state cut along a plane where the minor axis is located according to a preferred embodiment of the present invention;

[0043] Figure 8 for Figure 7 The middle D part is an enlarged schematic diagram;

[0044] Fig. 9 A schematic diagram of a button-type lithium-ion battery in a pre-installed state cut along a plane where the long axis is located according to a preferred embodiment of the present invention; and

[0045] Fig.10 A schematic diagram of a button-type lithium-ion battery in an installed and sealed state according to a preferred embodiment of the present invention.

[0046] Description of reference numerals:

[0047] 100: Button lithium-ion battery 110: Negative electrode shell

[0048] 111: negative electrode shell wall 112: negative electrode shell bottom

[0049] 113: Main body section 114: Second transition section

[0050] 115: Installation matching section 120: Positive electrode shell

[0051] 121: positive electrode shell wall 122: positive electrode shell bottom

[0052] 123: Fastening section 124: First transition section

[0053] 125: Pre-fastening section 126: Guide section

[0054] 130: Sealing ring 131: First vertical extension portion

[0055] 132: second vertical extension portion 133: lateral extension portion

[0056] 140: gap 150: receiving cavity

[0057] 151: Battery cell a: Long axis

[0058] b: short axis ε: tilt angle DETAILED DESCRIPTION

[0059] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0060] In order to fully understand the present invention, a detailed description will be provided in the following description. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. Obviously, the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0061] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0062] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and similar expressions used herein are for illustrative purposes only and are not limiting.

[0063] Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings.

[0064] Figures 1 to 9 A button-type lithium-ion battery 100 according to a preferred embodiment of the present invention is shown. Figure 1 Shows the installation status, Figures 2 to 6 Shows the status of Not Installed. Figures 7 to 9 The pre-installation state is shown.

[0065] refer to Figures 1 to 9 The button-type lithium-ion battery 100 of the present invention comprises a negative electrode casing 110 , a positive electrode casing 120 and a sealing ring 130 .

[0066] The negative electrode case 110 includes a negative electrode case bottom 112 and a negative electrode case wall 111 extending from the periphery of the negative electrode case bottom 112. The positive electrode case 120 includes a positive electrode case bottom 122 and a positive electrode case wall 121 extending from the periphery of the positive electrode case bottom 122. The positive electrode case 120 is sleeved to the negative electrode case 110, and the positive electrode case wall 121 is located outside the negative electrode case wall 111. The sealing ring 130 is at least partially located between the positive electrode case wall 121 and the negative electrode case wall 111. In addition, the positive electrode case 120 and the negative electrode case 110 enclose a housing chamber 150, and a battery cell 151 and an electrolyte are arranged in the housing chamber 150.

[0067] Specifically, please refer to the specific structure of the positive electrode shell wall 121 in the unmounted state. Figure 3 The positive electrode shell wall 121 includes a fastening section 123 , a first transition section 124 , a pre-fastening section 125 and a guide section 126 . The fastening section 123 is connected to the periphery of the positive electrode shell bottom 122 .

[0068] The first transition section 124 is connected to the fastening section 123, and the first transition section 124 is inclined outward, so that the first transition section 124 forms an inclined surface similar to a cone, or the first transition section 124 is roughly horn-shaped. The axial cross section of the first transition section 124 forms an angle, which can be 5 to 30 degrees. Preferably, the angle of the axial cross section of the first transition section 124 can be 9.15 to 25.91 degrees. In addition, the length of the first transition section 124 can account for 12.5% ​​of the length of the positive electrode shell wall 121.

[0069] The pre-snap-fit ​​section 125 is connected to the transition section, and the length of the pre-snap-fit ​​section 125 accounts for 25% to 45% of the length of the positive electrode shell wall 121. Preferably, the length of the pre-snap-fit ​​section 125 accounts for 35% of the total length of the positive electrode shell wall 121.

[0070] The guide section 126 is connected to the pre-snap fit section 125 and tilted outward, thereby forming a bell-mouth shape, which is conducive to the opening end of the negative electrode housing 110 entering the positive electrode housing 120 during installation. The axial cross section of the guide section 126 forms an angle, and the angle of the angle is 10 to 20 degrees. Preferably, the angle of the axial cross section of the guide section 126 is 16.13 degrees.

[0071] That is, the positive electrode case wall 121 includes a fastening section 123 , a first transition section 124 , a pre-fastening section 125 and a guiding section 126 in sequence along a direction away from the positive electrode case bottom 122 .

[0072] For the specific structure of the negative electrode shell wall 111, please refer to Figure 2 The negative electrode case wall 111 includes a body section 113, a second transition section 114 and a mounting section 115. The body section 113 is connected to the periphery of the negative electrode case bottom 112. The second transition section 114 is connected to the body section 113, and the second transition section 114 is inclined outward. The mounting section 115 is connected to the second transition section 114 and extends vertically.

[0073] That is, the negative electrode case wall 111 is sequentially composed of a body section 113, a second transition section 114, and an installation matching section 115 in a direction away from the negative electrode case bottom 112. Moreover, the sum of the radial dimension of the installation matching section 115 and the thickness of the sealing ring 130 located between the positive electrode case wall 121 and the negative electrode case wall 111 is greater than or equal to the radial dimension of the fastening section 123 of the positive electrode case wall 121. In this way, the installation matching section 115, the sealing ring 130, and the fastening section 123 form an interference fit, and then the sealing ring 130 between the positive electrode case 120 and the negative electrode case 110 in the installed state is in a compressed state, thereby forming a seal.

[0074] Furthermore, in the installed state, the compression rate of the portion of the sealing ring 130 between the installation matching section 115 and the fastening section 123 is 30% to 70%. Preferably, the compression rate is controlled to be 40%.

[0075] The second transition section 114 is tilted outward to form a step, so that the open end of the positive electrode shell wall 121 can be locked with the step after the sealing process is completed, which is conducive to sealing. Specifically, in the sealing process, the end of the guide section 126 of the positive electrode shell wall 121 presses the second vertical extension 132 of the sealing ring 130 inwardly to form a lock at the step. The sealing ring 130 completely isolates the positive electrode shell 120 and the negative electrode shell 110 to avoid short circuit.

[0076] For the specific structure of the sealing ring 130, please refer to Figure 4 The sealing ring 130 includes a first vertical extension portion 131, a second vertical extension portion 132 and a transverse extension portion 133. The first vertical extension portion 131 is located on the inner side of the negative electrode shell wall 111, the second vertical extension portion 132 is located on the outer side of the negative electrode shell wall 111 (or between the negative electrode shell wall 111 and the positive electrode shell wall 121), and the transverse extension portion 133 is connected to the ends of the first vertical extension portion 131 and the second vertical extension portion 132. When installed, the end of the negative electrode shell wall 111 abuts against the transverse extension portion 133. In other words, when installed, the end of the negative electrode shell wall 111 is partially accommodated in the groove formed by the first vertical extension portion 131, the second vertical extension portion 132 and the transverse extension portion 133.

[0077] Among them, the radial dimension of the second vertical extension portion 132 gradually increases in the direction away from the lateral extension portion 133. Preferably, the second vertical extension portion 132 is inclined outward in the direction away from the lateral extension portion 133. In addition, the inclination angle ε of the second vertical extension portion 132 is less than or equal to 3°. In addition, the thickness of the sealing ring 130 is uniform at all locations. The above-mentioned inclination angle ε can be understood as the draft angle when the sealing ring 130 is formed. As a result, the second vertical extension portion 132 of the sealing ring 130 forms a certain inclination, which is not only conducive to demolding during injection molding, but also conducive to guiding the downward movement of the positive electrode housing 120 during installation.

[0078] And, in the installed state, refer to Fig.10 The compression rate of the top of the second vertical extension 132 (corresponding to the portion between the installation matching section 115 and the fastening section 123) is preferably 40% as mentioned above. The compression rate of the middle of the second vertical extension 132 (corresponding to the portion between the installation matching section 115 and the pre-fastening matching section 125) is preferably 20%. The compression rate of the middle bottom of the second vertical extension 132 (corresponding to the portion between the second transition section 114 and the locked guide section 126) is preferably 70%.

[0079] In a preferred embodiment, the radial cross section of the negative electrode shell wall 111 is configured as a first shape. It is easy to understand that the radial cross sections of the body section 113, the second transition section 114 and the installation matching section 115 can all be configured as the first shape.

[0080] The radial cross section of the pre-snap fitting section 125 of the positive electrode shell wall 121 is configured as a second shape. The first shape and the second shape are not similar to each other, so that in the pre-installed state, a gap 140 can be formed between the pre-snap fitting section 125 and the sealing ring 130. In this embodiment, the first shape is a circle and the second shape is an ellipse. It is easy to understand that the first shape and the second shape can also be other shapes that are not similar to each other. For example, a square, a polygon, etc.

[0081] Since the first transition section 124 is connected to the pre-snap-fit ​​section 125, the cross-sectional shape of the end of the first transition section 124 close to the pre-snap-fit ​​section 125 is the second shape. In addition, the fastening section 123 is also connected to the first transition section 124, and the cross-sectional shape of the fastening section 123 is preferably the first shape. Therefore, the cross-sectional shape of the end of the first transition section 124 close to the fastening section 123 is the first shape. That is, the radial cross-sectional shape of the first transition section 124 gradually changes from the second shape to the first shape along the axial direction of the battery. In other words, in Figure 3In the illustrated embodiment, the top of the first transition section 124 is elliptical and the bottom is circular. It is easy to understand that since the guide section 126 is connected to the first transition section 124 and the guide section 126 is located at the outermost side of the positive electrode shell wall 121, the cross-sectional shape of the guide section 126 is preferably the second shape. Figure 7 , Figure 8 and Fig. 9 The pre-installation state refers to the state in which the positive electrode housing 120 moves downward and gradually covers the negative electrode housing 110 under the action of the downward pressure F, and when a certain point on the pre-snap-fit ​​section 125 of the positive electrode housing wall 121 stops moving downward due to interference with the sealing ring 130. In the pre-installation state, the height of the pre-snap-fit ​​section 125 corresponds to the height of the installation fitting section 115, so the above-mentioned gap 140 is formed between the pre-snap-fit ​​section 125 and the second vertical extension 132.

[0082] Installation Status Reference Figure 1 The installed state refers to the state in which the positive electrode housing 120 completely covers the negative electrode housing 110, or in other words, the positive electrode housing 120 is in contact with the top of the sealing ring 130. In addition, in the installed state, the battery has completed the vacuum pumping process, and the air pressure in the receiving chamber 150 is lower than the external air pressure.

[0083] Not Installed Status Reference Figure 2 , Figure 3 and Figure 6 The unmounted state refers to a state in which the positive electrode case 120 and the negative electrode case 110 are separated.

[0084] Further, refer to Figure 5 The radial cross-section of the pre-fastening section 125 is preferably an ellipse, and its eccentricity is 0.08 to 0.3. More preferably, the eccentricity of the ellipse is 0.135 to 0.178. Optionally, the radial cross-section of the guide section 126 may also be an ellipse.

[0085] The radial cross-sectional shape of the pre-fastening fitting section 125 has a major axis a and a minor axis b, that is, the major axis and the minor axis of the ellipse. Moreover, the dimension of the major axis a is greater than the sum of the radial dimension of the installation fitting section 115 and the thickness of the second vertical extension 132, and the dimension of the minor axis b is less than or equal to the sum of the radial dimension of the installation fitting section 115 and the thickness of the second vertical extension 132.

[0086] Thus, in the pre-installed state, the second vertical extensions 132 of the sealing ring 130 on both sides of the minor axis b are in interference fit with the pre-fastening sections 125 of the positive electrode shell side wall, so that the sealing ring 130 is compressed, and the friction force generated by the contact surface of the two prevents the positive electrode shell 120 from rebounding, thereby enabling the positive electrode shell 120 to remain in the current position (such as Figure 7 and Figure 8As shown). At this time, there is a gap 140 (gap fit) between the pre-fastening fitting sections 125 on both sides of the long axis a and the sealing ring 130, thereby leaving a gas flow channel for vacuuming to ensure that the internal gas can be discharged smoothly during vacuuming (as shown). Fig. 9 shown).

[0087] According to the button-type lithium-ion battery of the present invention, during pre-installation, a gap is left between the positive electrode shell and the sealing ring to form a vacuum channel, so that the air in the battery can be discharged through the channel during vacuuming. While ensuring the precise buckling and positioning of the battery, the vacuuming effect can also be ensured, thereby improving the stability of automated production and greatly improving production efficiency.

[0088] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

[0089] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A button-type lithium-ion battery, characterized in that: include: A negative electrode casing, the negative electrode casing comprising a negative electrode casing wall, the radial cross section of the negative electrode casing wall being configured in a first shape, the first shape being a circle; A positive electrode shell, the positive electrode shell is sleeved on the negative electrode shell, the positive electrode shell includes a positive electrode shell wall, the positive electrode shell wall is located outside the negative electrode shell wall, the positive electrode shell wall includes a pre-fastening and fitting segment, the radial cross-section of the pre-fastening and fitting segment is configured as a second shape, the second shape is an ellipse, the positive electrode shell and the negative electrode shell form a receiving cavity, and a battery cell and an electrolyte are arranged in the receiving cavity; and A sealing ring, the sealing ring being at least partially located between the positive electrode shell wall and the negative electrode shell wall; Among them, the radial cross-sectional shape of the pre-snap-fit ​​section has a major axis and a minor axis, so that in the pre-installed state, the sealing rings on both sides of the minor axis can form an interference fit with the pre-snap-fit ​​section, and a gap can be formed between the pre-snap-fit ​​section and the sealing ring on both sides of the major axis, and the gap forms a vacuum channel, and the vacuum channel allows the air in the accommodating chamber to be discharged through the vacuum channel during vacuuming, so that in the installed state, the air pressure in the accommodating chamber is lower than the external air pressure.

2. The button-type lithium-ion battery according to claim 1, characterized in that: The eccentricity of the ellipse is 0.08-0.

3.

3. The button-type lithium-ion battery according to claim 2, characterized in that: The eccentricity of the ellipse is 0.135-0.

178.

4. The button-type lithium-ion battery according to claim 1, characterized in that: The positive electrode shell comprises a positive electrode shell bottom and a positive electrode shell wall extending from the periphery of the positive electrode shell bottom, and the positive electrode shell wall comprises: A fastening section, the fastening section is connected to the bottom of the positive electrode case, and in the installed state, the compression rate of the sealing ring at the fastening section is 30% to 70%; a first transition section, the first transition section being connected to the fastening section, the first transition section being inclined outwardly; the snap-fit ​​section connected to the first transition section; and A guide section is connected to the buckle-fit section, and the guide section is inclined outward.

5. The button-type lithium-ion battery according to claim 4, characterized in that: The negative electrode case comprises a negative electrode case bottom and a negative electrode case wall extending from the periphery of the negative electrode case bottom, wherein the negative electrode case wall comprises: A body segment connected to the bottom of the negative electrode shell; a second transition section, the second transition section being connected to the body section, the second transition section being inclined outwardly; An installation fitting section is connected to the second transition section, and the sum of the radial dimension of the installation fitting section and the thickness of the sealing ring located between the positive electrode shell wall and the negative electrode shell wall is greater than or equal to the radial dimension of the fastening section.

6. The button-type lithium-ion battery according to claim 5, characterized in that: The sealing ring comprises: A first vertical extension portion, wherein the first vertical extension portion is located on the inner side of the negative electrode shell wall; a second vertical extension portion, the second vertical extension portion being located outside the negative electrode shell wall; a transverse extension portion, the transverse extension portion being connected to ends of the first vertical extension portion and the second vertical extension portion, and the end of the negative electrode case wall being abutted against the transverse extension portion; Wherein, the radial dimension of the second vertical extension portion gradually increases in a direction away from the lateral extension portion.

7. The button-type lithium-ion battery according to claim 6, characterized in that: The second vertical extension portion is inclined outwardly in a direction away from the lateral extension portion, and an inclination angle of the second vertical extension portion is less than or equal to 3°.

8. The button-type lithium-ion battery according to claim 6, characterized in that: The size of the major axis is greater than the sum of the radial size of the installation fitting section and the thickness of the second vertical extension portion, and the size of the minor axis is less than or equal to the sum of the radial size of the installation fitting section and the thickness of the second vertical extension portion.

9. The button-type lithium-ion battery according to claim 1, characterized in that: The length of the pre-fastening section accounts for 25% to 45% of the length of the positive electrode shell wall.

10. The button-type lithium-ion battery according to claim 6, characterized in that: In the pre-installation state, the height of the pre-snap-fit ​​section corresponds to the height of the installation-snap-fit ​​section, and the gap is formed between the pre-snap-fit ​​section and the second vertical extension portion.

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