CN213071199U

CN213071199U - Secondary button cell

Info

Publication number: CN213071199U
Application number: CN202021620758.2U
Authority: CN
Inventors: 常海涛; 陈娟; 张志明; 许华灶; 徐志锋; 叶永锋; 刘国镇
Original assignee: Nanfu New Energy Technology Co ltd Yanping District Nanping Fujian
Current assignee: Nanfu New Energy Technology Co ltd Yanping District Nanping Fujian
Priority date: 2020-08-06
Filing date: 2020-08-06
Publication date: 2021-04-27
Anticipated expiration: 2030-08-06

Abstract

The utility model discloses a secondary button cell, including negative pole casing, anodal casing and sealing washer. The negative electrode case includes a negative electrode case wall. The positive shell comprises a positive shell bottom and a positive shell wall positioned outside the negative shell wall. The sealing ring comprises a first sealing section and a second sealing section, the first sealing section is sleeved at the bottom end of the negative shell wall, the second sealing section is located above the first sealing section and connected with the first sealing section, and the second sealing section is located between the positive shell wall and the negative shell wall. In an unassembled state, a ratio of a first radial spacing of the positive and negative casing walls at a first height to a radial dimension of the first seal segment at the corresponding height is K1; in the unassembled state, the ratio of the second radial spacing of the positive and negative casing walls at the second height to the radial dimension of the second seal segment at the corresponding height is K2, with K2 not being equal to K1. According to the utility model discloses a secondary button cell forms the sealed of two levels, has improved the encapsulation reliability.

Description

Secondary button cell

Technical Field

The utility model relates to a battery technology field particularly relates to a secondary button cell.

Background

Because the steel shell button lithium ion battery has small volume and high energy density, the steel shell button lithium ion battery is more and more widely applied to the field of internet of things and the field of intelligent wearing.

However, with the diversification of application scenarios, the requirements for batteries are also higher and higher, and particularly, a leakage phenomenon that does not occur during storage, transportation or use of the batteries is required.

However, the conventional secondary button cell has the problems of insufficient packaging reliability, and phenomena of liquid leakage, weight loss and the like are easy to occur.

Therefore, there is a need for a secondary button cell that at least partially solves the above problems.

SUMMERY OF THE UTILITY MODEL

In the summary section a series of concepts in a simplified form is introduced, which will be described in further detail in the detailed description section. The inventive content does not imply any attempt to define the essential features and essential features of the claimed solution, nor is it implied to be intended to define the scope of the claimed solution.

For at least partly solving above-mentioned problem, the utility model provides a secondary button cell, include:

a negative electrode can including a negative electrode can wall;

a positive casing including a positive casing bottom and a positive casing wall extending upward from a periphery of the positive casing bottom, the positive casing wall being located outside the negative casing wall; and

a seal ring, the seal ring comprising:

a first sealing section sleeved to the bottom end of the negative casing wall; and

a second seal section positioned above and connected to the first seal section, the second seal section positioned between the positive casing wall and the negative casing wall;

wherein, in an unassembled state, a ratio of a first radial separation of the positive and negative casing walls at a first elevation to a radial dimension of the first seal segment at a corresponding elevation is K1;

in an unassembled state, a ratio of a radial second spacing of the positive and negative casing walls at a second height to a radial dimension of the second seal segment at a corresponding height is K2, the K2 is not equal to the K1.

According to the secondary button battery, the radial compression amount of the first sealing section and the second sealing section of the sealing ring is different, two-level sealing protection is formed, and the packaging reliability is improved; and the assembly difficulty is reduced, and the production efficiency is improved.

Further, said K₂0.9 to 0.95.

Further, said K₁0.75 to 0.9.

Further, the first seal segment includes:

a radial extension between a bottom end of the negative casing wall and the positive casing bottom;

a first axial extension inside the negative casing wall, the first axial extension extending upward from one end of the radial extension;

a second axial extension between the positive casing wall and the negative casing wall, the second axial extension extending upward from the other end of the radial extension, and having an axial dimension greater than the axial dimension of the first axial extension.

Further, the ratio of the distance between the bottom end of the negative casing wall and the positive casing bottom to the axial dimension of the radial extension is K₃Said K is₃Is 0.75-0.95.

Further, the axial dimension of the first seal segment is 30-40% of the total axial dimension of the seal ring.

Further, a positive electrode sealing glue layer is arranged between the first sealing section and the inner corner part of the positive electrode shell.

Further, a negative electrode sealant layer is arranged between the first sealing section and the negative electrode shell wall.

Further, the sealing ring further comprises a third sealing section, the third sealing section extends from the end of the second sealing section to exceed the top end of the positive electrode shell wall, and the length of the third sealing section is 2-3% of the length of the positive electrode shell wall.

Further, a recess portion which is recessed inwards in the radial direction is arranged at the position of the positive electrode shell wall corresponding to the height of the second axial extension portion.

Drawings

The following drawings of the present invention are used herein as part of the present invention for understanding the present invention. There are shown in the drawings, embodiments and descriptions of the invention, which are used to explain the principles of the invention.

In the drawings:

fig. 1 is a schematic front view of a secondary button battery according to the present invention;

FIG. 2 is a sectional view of the secondary button cell in FIG. 1;

FIG. 3 is an enlarged view of portion A of FIG. 2; and

figure 4 is according to the utility model discloses a secondary button cell circulation charge-discharge test result.

Description of reference numerals:

100: secondary button cell 110: negative electrode case 111: cathode casing bottom

112: negative electrode shell wall 120: positive electrode case 121: positive electrode bottom

122: positive electrode shell wall 123: the recessed portion 130: sealing ring

131: first seal segment 132: second seal section 133: third seal segment

134: radial extension 135: first axial extension 136: second axial extension

140: battery cell

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention.

In the following description, a detailed description will be given for a thorough understanding of the present invention. It is apparent that 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, however, other embodiments of the present invention are possible in addition to these detailed descriptions.

It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the invention. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Ordinal words such as "first" and "second" are referred to in this application as labels only, and do not have any other meanings, such as a particular order, etc. Also, for example, the term "first component" does not itself imply the presence of "second component", and the term "second component" does not itself imply the presence of "first component".

It is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like are used herein for purposes of illustration only and are not limiting.

Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art.

The secondary button cell 100 of the present invention will be described in detail with reference to fig. 1, 2 and 3.

Please refer to fig. 1 and fig. 2. The secondary button cell 100 includes a positive electrode case 120, a negative electrode case 110, a sealing ring 130, and a battery cell 140. The positive electrode case 120 and the negative electrode case 110 are preferably made of a metal material, such as a type 304, a type 430, or a type 316 stainless steel material.

Specifically, please refer to fig. 2 and 3. The positive electrode case 120 includes a positive electrode case bottom 121 and a positive electrode case wall 122 extending upward from a periphery of the positive electrode case bottom 121, the positive electrode case wall 122 enclosing a top opening. The negative electrode case 110 includes a negative electrode case bottom 111 and a negative electrode case wall 112 extending downward from the periphery of the negative electrode case bottom 111, the negative electrode case wall 112 being located inside the positive electrode case wall 122, the negative electrode case wall 112 enclosing a bottom opening. The negative electrode case 110 is inserted into the positive electrode case 120 with the bottom opening facing the top opening, and the positive electrode case 120 and the negative electrode case 110 enclose an accommodating chamber. The accommodating cavity is provided with a battery cell 140 and electrolyte.

With continued reference to fig. 2 and 3. The sealing ring 130 is substantially composed of a first sealing section 131, a second sealing section 132 and a third sealing section 133. The material of the sealing ring 130 is preferably polypropylene, polybutylene terephthalate, or a mixture of the two.

Wherein the first sealing section 131 is sleeved to the bottom end of the negative casing wall 112, and the axial dimension of the first sealing section 131 preferably accounts for 30-40% of the total axial dimension of the sealing ring 130; a second seal section 132 is located above the first seal section 131 and connected to the first seal section 131, the second seal section 132 being located between the positive casing wall 122 and the negative casing wall 112; the third sealing section 133 is located above the second sealing section 132 and connected to the second sealing section 132, or the third sealing section 133 extends from the top end of the second sealing section 132 to beyond the top end of the positive casing wall 122, and the length of the third sealing section 133 is preferably 2-3% of the length of the positive casing wall 122.

Wherein, in an unassembled state, a ratio of a first radial spacing of the positive casing wall 122 and the negative casing wall 112 at a first height to a radial dimension of the first seal segment 131 at the corresponding height is K₁. That is, in the assembled state, the radial compression ratio of the first seal segment 131 is (1-K)₁) X 100%. The first height refers to a portion of the positive electrode casing wall 122 that contacts the first seal segment 131 in the assembled state. The corresponding height refers to a corresponding portion of the first seal segment 131 that is at the same height as the first height in the assembled state.

In the unassembled state, the ratio of the second radial spacing of the positive and

negative casing walls

122, 112 at the second elevation to the radial dimension of the second seal segment 132 at the corresponding elevation is K₂. That is, in the assembled state, the radial compression ratio of the second seal segment 132 is (1-K)₂) X 100%. The second height is a portion of the positive electrode casing wall 122 that contacts the second seal segment 132 in the assembled state. By corresponding height is meant that, in the assembled state, the second seal segment 132 is located at the same height as the second heightA corresponding portion of a height.

The unassembled state is a state in which the positive electrode case 120 and the negative electrode case 110 are engaged with each other without the sealing ring 130 attached thereto; the assembled state refers to a state in which the secondary button cell 100 is completely assembled (including the gasket 130).

And, K₂Is not equal to K₁. That is, the radial compression rates of the first and

second seal segments

131 and 132 are different.

According to the secondary button cell 100 of the present invention, the radial compression amount of the first sealing section 131 and the second sealing section 132 of the sealing ring 130 is different, thereby forming two levels of sealing protection and improving the packaging reliability; and the assembly difficulty is reduced, and the production efficiency is improved.

Preferably, K₂Greater than K₁. That is, the radial compression rate of the first seal segment 131 is greater than that of the second seal segment 132. Thus, the resistance in the process of mounting the buckle can be reduced, and the mounting can be completed in one time.

K₁Is 0.75 to 0.9, i.e. the first seal segment 131 has a radial compression ratio of preferably 10% to 25%, for example from 0.4mm to 0.3 mm. K₂Preferably 0.9 to 0.95, i.e., the radial compressibility of the second seal segment 132 is preferably 5% to 10%.

Please refer to fig. 3 for a specific structure of the first sealing section 131. The first seal segment 131 is generally configured in cross-section as a U-shape including a radial extension 134, a first axial extension 135, and a second axial extension 136.

The radial extension 134 is located between the bottom end of the negative casing wall 112 and the positive casing bottom 121. The first axial extension 135 is located inside the negative electrode casing wall 112, and extends upward from one end of the inside of the radial extension 134. The second axial extension 136 is located between the positive casing wall 122 and the negative casing wall 112, extends upward from one end of the outside of the radial extension 134, and the axial dimension of the second axial extension 136 is greater than the axial dimension of the first axial extension 135, or the length of the second axial extension 136 is greater than the length of the first axial extension 135. Thus, the axial dimension of the first seal segment 131 is the axial dimension of the first axial extension 135.

To improve the sealing property, the ratio of the distance between the bottom end of the negative electrode casing wall 112 and the positive electrode casing bottom 121 to the axial dimension of the radial extension 134 is K₃，K₃Is 0.75-0.95. That is, the axial compression ratio of the radially extending portion 134 is 5% to 25%, for example, from 0.2mm to 0.15 mm.

Electrolyte is injected into the secondary button cell 100, and there are two main leakage channels for the electrolyte. One is leakage through the seal ring 130 and the positive electrode case 120, and the other is leakage through the seal ring 130 and the negative electrode case 110. In particular, the electrolyte may be subject to capillary permeation through the channels.

For this purpose, a positive sealant is applied to the corner R where the first sealing segment 131 and the positive casing 120 are in contact, based on the axial compression and radial compression of the sealing ring 130 described above. That is, a positive electrode sealant layer is disposed between the first sealing segment 131 and the inner corner portion of the positive electrode case 120. A negative sealant is coated in the U-shaped groove of the first sealing section 131, i.e., a negative sealant layer is disposed between the first sealing section 131 and the negative casing wall 112. The positive sealant and/or the negative sealant is preferably electrolyte corrosion resistant asphalt rubber, olefin resin rubber or special rubber.

In addition, in order to further prevent the electrolyte from leaking between the seal ring 130 and the positive electrode case 120, the positive electrode case wall 122 is provided with a recessed portion 123 recessed inward in the radial direction at a height corresponding to the second axial extension 136. After the encapsulation is completed, the wire winding can be performed on the recess 123 to improve the local radial compression rate; or the recess 123 may be formed by wire-turn extrusion.

Example 1: the lithium ion secondary battery with the diameter of 12mm and the height of 5.4mm is prepared, and the sealing ring 130 is formed by polypropylene injection molding.

Firstly, coating the negative sealant in the groove of the sealing ring 130, and drying the groove to be in a semi-dry state at 23 ℃ or at high temperature. The negative casing 110 is then inserted into the groove of the sealing ring 130. A thin layer of positive sealant is then uniformly applied to the R corner of the positive housing 120. The cell 140 is then electrically connected to the positive casing 120 and the negative casing 110. The cell 140 was then vacuum dried at 85 ℃ for 12 hours and the electrolyte was injected. And finally, buckling the positive shell 120 and the negative shell 110, and stretching the positive shell and the negative shell through a die to control the compression amount of the first sealing section 131 to be 25 percent, the compression amount of the second sealing section 132 to be 5 percent, and the length of the third sealing section 133 to be 2 to 3 percent more than that of the positive shell cover. The battery is subjected to standing, formation and capacity grading, and then charged to a 100% SOC state for testing.

The test comprises the following steps:

the samples were stored at 85 ℃ for 8 hours according to the high-temperature storage test shown in Table 1.

TABLE 1

The samples were stored at 60 ℃ for 21 days according to the high-temperature storage test shown in Table 2.

TABLE 2

The samples were stored at 25 ℃ for 30 days in the ambient temperature storage test shown in Table 3.

TABLE 3

As the temperature cycle storage test shown in Table 4, the storage was performed alternately at 75 ℃ and-40 ℃ for 1 hour each while evacuating, and 10 cycles were performed.

TABLE 4

And as shown in fig. 4, the cycle charge and discharge test, in which the battery is charged to 4.2V with a constant current and a constant voltage at 0.5C rate, and after the current is cut off at 0.02C, the battery is discharged to 3.0V with 0.5C, and the test is performed for 1000 cycles. From fig. 4, the utility model discloses a secondary button cell capacity is 63mAh before the circulation, and the capacity is 58mAh after the circulation, and the capacity retention rate is 92%, is greater than 85%, and high expansion rate < 3%, the reliability is high.

And can know by the result of table 1 to table 4, the utility model discloses a secondary button cell dimensional stability is good, internal resistance stability is strong and the weightlessness rate is little.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Features described herein in one embodiment may be applied to another embodiment, either alone or in combination with other features, unless the feature is otherwise inapplicable or otherwise stated in the other embodiment.

The present invention has been described in terms of the above embodiments, but it is to be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the invention to the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many more modifications and variations are possible in light of the teaching of the present invention and are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A secondary button cell, comprising:

a negative electrode can including a negative electrode can wall;

a seal ring, the seal ring comprising:

in an unassembled state, a ratio of a second radial spacing of the positive and negative casing walls at a second elevation to a radial dimension of the second seal segment at a corresponding elevation is K2, the K2 is not equal to the K1.

2. The secondary button cell as defined in claim 1, wherein the K is₂0.9 to 0.95.

3. The secondary button cell as defined in claim 1, wherein the K is₁0.75 to 0.9.

4. The secondary button cell according to claim 1, wherein the first seal segment comprises:

5. The secondary button cell according to claim 4, wherein the ratio of the distance between the bottom end of the negative casing wall and the positive casing bottom to the axial dimension of the radial extension is K₃Said K is₃Is 0.75-0.95.

6. The secondary button cell according to claim 1, wherein the axial dimension of the first seal segment is 30-40% of the total axial dimension of the seal ring.

7. The secondary button cell according to claim 1, wherein a positive sealant layer is disposed between the first sealing segment and the inner corner portion of the positive casing.

8. The secondary button cell according to claim 1, wherein a negative sealant layer is disposed between the first seal segment and the negative casing wall.

9. The secondary button cell according to claim 1, wherein the sealing ring further comprises a third sealing section extending from an end of the second sealing section beyond a top end of the positive casing wall, the third sealing section having a length of 2-3% of the positive casing wall length.

10. The secondary button cell according to claim 4, wherein a recess is provided in the positive casing wall at a height corresponding to the second axial extension, the recess being recessed radially inward.