Button-type lithium ion battery and preparation method thereof

Abstract

The application relates to the field of lithium ion batteries, and discloses a button-type lithium ion battery and a preparation method thereof. The method comprises the following steps: stamping a first pole shell to form a first top cover and a first shell wall around the edge of the first top cover, the first shell wall comprises at least two cylindrical ring segments in the axial direction and each outer convex ring segment formed by bending between every two adjacent cylindrical ring segments; the inner and outer diameters of each cylindrical ring segment are the same; the outer diameters of any two cylindrical ring segments are different; the outer diameter of the cylindrical ring segment close to the first top cover is narrower than that of the cylindrical ring segment close to the opening of the first pole shell; the outer diameter of each outer convex ring segment gradually narrows in the direction from the opening of the first pole shell to the first top cover in the axial direction; a second pole shell is stamped, a sealing ring is sleeved on the first pole shell, an electric core is arranged in the first pole shell, the second pole shell is sleeved on the opening of the first pole shell, liquid injection is carried out, the second shell wall is pressed to be attached to the first shell wall, and the sealing ring is sealed. The scheme is favorable for improving the sealing performance of the button-type lithium ion battery.

Description

Technical Field

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

[0002] With the increasing adoption of smart wearables, demand for compact lithium-ion button-shaped rechargeable batteries (also known as button-shaped lithium-ion batteries) is growing. Button-shaped lithium-ion batteries are increasingly being used in smart wearables, such as headphones. Improving the sealing performance of button-shaped batteries is a major challenge.

[0003] During the research process of the present invention, it was found that the current button-type batteries use a one-stage compression seal, which has a sealing risk, especially when stored and circulated to a certain extent, there is a risk of leakage. Summary of the Invention

[0004] One of the purposes of the embodiments of the present invention is to provide a button-type lithium-ion battery and a preparation method thereof. The use of this technical solution is conducive to improving the sealing performance of the button-type lithium-ion battery.

[0005] In a first aspect, an embodiment of the present invention provides a method for preparing a button-type lithium-ion battery, comprising:

[0006] A first metal sheet is stamped to form a first pole housing, a first top cover, and a first housing wall surrounding the edge of the first top cover, wherein the first housing wall includes at least two cylindrical ring segments along the axial direction and each convex ring segment formed by bending between two adjacent cylindrical ring segments; each cylindrical ring segment has the same inner and outer diameters; any two cylindrical ring segments have different outer diameters; the outer diameter of the cylindrical ring segment near the first top cover is narrower than the outer diameter of the cylindrical ring segment near the opening of the first pole housing; and the outer diameter of each convex ring segment gradually narrows along the axial direction from the opening of the first pole housing toward the first top cover;

[0007] stamping a second metal sheet to form a second pole shell, a second top cover, and a second shell wall surrounding an edge of the second top cover;

[0008] A sealing ring is connected to the outer surface of the first pole shell, and the inner wall of the sealing ring is in close contact with the outer wall of the first shell wall and the end face of the opening;

[0009] A battery cell is placed in the first pole shell, so that one of the positive electrode and the negative electrode of the battery cell is electrically connected to the first pole shell, and the other is electrically connected to the second pole shell;

[0010] The second pole shell is sleeved relative to the opening of the first pole shell, liquid is injected, the second shell wall is pressed tightly against the first shell wall, and the sealing ring is pressed and sealed.

[0011] Optionally, a raised annular boss and an inwardly recessed groove are provided on the outer wall of the sealing ring.

[0012] When the opening of the first top cover faces downward, the groove is located below the annular boss and extends to the opening position of the first pole shell.

[0013] The annular boss is pressed between the first shell wall and the second shell wall to seal the gap between the first shell wall and the second shell wall, and the groove completely enters between the first shell wall and the second shell wall.

[0014] When the second pole shell is relative to the opening of the first pole shell, the sleeve is placed until the annular boss is located outside the second shell wall and the groove is partially exposed outside the second shell wall, and the sleeve is stopped.

[0015] A predetermined amount of electrolyte is poured into the groove, and the electrolyte flows along the groove into the cavity between the first pole shell and the second pole shell, and the filling is completed.

[0016] The first pole housing and the second pole housing are further sleeved until the groove completely enters between the first housing wall and the second housing wall, and the annular boss is pressed between the first housing wall and the second housing wall to seal the gap between the first housing wall and the second housing wall, and the first pole housing and the second pole housing are completely sleeved.

[0017] The second shell wall is pressed tightly against the first shell wall to compress the sealing ring.

[0018] In a second aspect, an embodiment of the present invention provides a button-type lithium-ion battery housing, comprising:

[0019] The first pole case includes an integrally formed first top cover and a first shell wall, wherein the first shell wall is located on one side of the first top cover and surrounds the edge of the first top cover, and the first shell wall includes at least two cylindrical ring segments and each convex ring segment formed by bending between every two adjacent cylindrical ring segments; each cylindrical ring segment has the same inner and outer diameters; the outer diameters of any two cylindrical ring segments are different; the outer diameters of the cylindrical ring segments near the first top cover are narrower than the outer diameters of the cylindrical ring segments near the opening of the first pole case; the outer diameter of each convex ring segment gradually narrows axially from the opening of the first pole case toward the first top cover, and the inner and outer diameters of the sealing ring segment gradually narrow from the opening of the first pole case toward the first top cover;

[0020] A sealing ring, tightly sleeved on the first pole shell;

[0021] The second pole housing includes an integrally formed second top cover and a second housing wall. The second housing wall surrounds the edge of the second top cover, is perpendicular to the second top cover, and is located on one side of the second top cover.

[0022] The openings of the first pole housing and the second pole housing are relatively sleeved, the second housing wall is tightly sleeved outside the first housing wall, and the sealing ring is spaced between the first pole housing and the second pole housing;

[0023] The first top cover and the second top cover are respectively located at the axial ends of the first shell wall and the second shell wall which are connected with each other, and the first pole shell and the second pole shell form a sealed chamber.

[0024] Optionally, the sealing ring segment includes: at least three cylindrical ring segments, and two outwardly convex ring segments formed by bending between every two adjacent cylindrical ring segments.

[0025] Optionally, the difference in outer diameters of the two cylindrical ring segments located at two axial ends of any one of the outer convex ring segments is 0.1 mm to 1 mm.

[0026] Optionally, the radially protruding width of any of the outer protruding ring segments is 0.05 mm to 0.5 mm.

[0027] Optionally, the inner wall of the sealing ring is in close contact with the outer wall of the first shell wall and the end face of the opening.

[0028] Optionally, a raised annular boss and an inwardly recessed groove are provided on the outer wall of the sealing ring.

[0029] When the opening of the first top cover faces downward, the groove is located below the annular boss and extends to the opening position of the first pole shell.

[0030] The annular boss is pressed between the first shell wall and the second shell wall to seal the gap between the first shell wall and the second shell wall, and the groove completely enters between the first shell wall and the second shell wall.

[0031] Optionally, at least two grooves are provided on the outer wall of the sealing ring.

[0032] Optionally, the grooves are distributed around the outer wall of the sealing ring.

[0033] Optionally, each of the grooves is parallel to the axial direction of the sealing ring.

[0034] Optionally, the axial width of the annular boss is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

[0035] Optionally, the depth of the groove is 1 / 2 of the thickness of the first shell wall where the groove is located.

[0036] Optionally, the wall thickness of the first cylindrical ring segment of the second shell wall at the end of the opening side is greater than the wall thickness of the ring segment between the first cylindrical ring segment and the second top cover;

[0037] The first cylindrical ring segment of the second shell wall is tightly pressed against the outside of the sealing ring outside the outer convex ring segment close to the first top cover.

[0038] Optionally, the outer diameters of the second shell wall are consistent, and the inner diameter of the first cylindrical ring segment of the second shell wall is smaller than the inner diameter of the ring segment between the first cylindrical segment and the second top cover.

[0039] Optionally, the wall thickness of the first cylindrical ring segment of the second shell wall is greater than or equal to 0.15 mm and less than or equal to 0.25 mm.

[0040] Optionally, except for the first cylindrical ring segment, the wall thickness of the second shell wall is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

[0041] Optionally, the wall thickness of the outwardly protruding ring segment of the first shell wall close to the first top cover is greater than the wall thickness of the ring segment between the outwardly protruding ring segment and the opening of the first pole shell.

[0042] Optionally, the outer convex ring segment of the first shell wall close to the first top cover, the first top cover, and the wall thickness from the first top cover to the outer convex ring segment are consistent.

[0043] Optionally, a wall thickness of the outer convex ring segment of the first shell wall close to the first top cover is greater than or equal to 0.15 mm and less than or equal to 0.25 mm.

[0044] Optionally, the wall thickness of the ring segment of the first shell wall from the outwardly protruding ring segment close to the first top cover to the opening of the first shell wall is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

[0045] Optionally, the first pole housing and the second pole housing are respectively steel housings.

[0046] In a second aspect, an embodiment of the present invention provides a button-type lithium-ion battery, comprising:

[0047] Any of the button-type lithium-ion battery casings described above,

[0048] A battery cell, comprising a positive electrode sheet, a negative electrode sheet, and a separator, wherein the separator is spaced between any adjacent positive and negative electrode sheets, and one of the positive electrode and the negative electrode of the battery cell is electrically connected to the first electrode shell, and the other is electrically connected to the second electrode shell;

[0049] The electrolyte is immersed in the battery cell.

[0050] As can be seen from the above, the technical solution of this embodiment, because the outer diameter of the button-type lithium-ion battery casing of this embodiment changes in multiple steps along the axial direction, is provided on the inner first shell wall with multiple cylindrical ring segments along the axial direction, and a radially protruding outer ring segment is provided between each two cylindrical ring segments. In this way, when sealing the second shell wall, in addition to the radially inward force applied to the second shell wall, the outer shell wall is also pressed inward, and the second shell wall at the first outer ring segment is also pressed downward against the first outer ring segment, pressing the second shell wall tightly against the first outer ring segment. The first outer ring segment provides a radial support for the compression of the second shell wall, thereby improving the sealing performance of the second shell wall. Furthermore, because the first outer ring segment adopts a variable diameter structure, it is less prone to radial deformation, which further improves the sealing performance of the button-type lithium-ion battery after storage or cycling.

[0051] Moreover, in this embodiment, the outer diameter of the first shell wall changes in a single direction from the first top cover to the opening, which is from narrow to wide. This can be achieved by stamping, which has a simple processing technology, low processing cost, and is not easy to deform after processing.

[0052] In this embodiment, by providing multiple outward convex ring segments, the axial width of each cylindrical ring segment is greatly shortened, the strength is greatly improved and it is not easy to deform, which is more conducive to the thinning design of the shell. In addition, in this embodiment, the radial outward convex width of each outward convex ring segment can be set narrower, thereby ensuring the volume for accommodating the battery cell in the shell, which is conducive to increasing the capacity of the button-type lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute an improper limitation of the present invention.

[0054] Figure 1 A schematic structural diagram of a first pole housing provided in Example 1 of the present invention;

[0055] Figure 2 A schematic structural diagram of the second pole housing provided in Example 1 of the present invention;

[0056] Figure 3 A schematic diagram of the assembly structure of a button-type lithium-ion battery housing provided in Example 1 of the present invention;

[0057] Figure 4 A schematic structural diagram of a button-type lithium-ion battery housing provided in Example 1 of the present invention;

[0058] Figure 5 A schematic structural diagram of a first pole housing provided in Example 2 of the present invention;

[0059] Figure 6A schematic structural diagram of a second pole housing provided in Example 2 of the present invention;

[0060] Figure 7 A schematic structural diagram of a button-type lithium-ion battery housing provided in Example 2 of the present invention;

[0061] Figure 8 A schematic diagram of the sealing ring structure provided in Example 3 of the present invention;

[0062] Figure 9 This is a schematic cross-sectional view of a button-type lithium-ion battery during liquid injection provided in Example 3 of the present invention;

[0063] Figure 10 for Figure 9 An enlarged structural diagram of component A in FIG;

[0064] Figure 11 A schematic cross-sectional view of a button-type lithium-ion battery housing provided in Example 4 of the present invention;

[0065] Figure 12 This is a schematic diagram of the button-type lithium-ion battery structure provided in Experimental Example 5 of the present invention.

[0066] Reference numerals

[0067] 1: first pole housing; 11: first top cover; 12: first pole housing;

[0068] 121: first cylindrical ring segment of the first shell wall; 122: second cylindrical ring segment; 123: third cylindrical ring segment;

[0069] 131: first outer convex ring segment;

[0070] 2: Second pole shell; 21: Second top cover; 22: Second shell wall;

[0071] 221: first cylindrical ring segment of the second shell wall;

[0072] 3: sealing ring; 31: annular boss; 32: groove; 14: annular platform. DETAILED DESCRIPTION

[0073] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0074] Example 1.

[0075] See also Figure 1-4 As shown,

[0076] This embodiment provides a button-type lithium-ion battery, which mainly includes: a battery cell, an electrolyte immersed in the battery cell, and a shell for sealing the battery cell. The battery cell can be a laminated battery cell or, but is not limited to, a wound battery cell. The battery cell includes a positive electrode sheet, a negative electrode sheet, and a separator, with the separator being spaced between adjacent positive and negative electrode sheets. The first electrode shell 1 of one of the positive and negative electrode shells of the battery cell is electrically connected, and the other is electrically connected to the second electrode shell 2, so that the two electrode shells constituting the shell serve as electrodes of the button-type lithium-ion battery to provide external power. This embodiment can, but is not limited to, use the first electrode shell 1 as the negative electrode and the second electrode shell 2 as the positive electrode for illustration, but is not limited to this.

[0077] The pole case of this embodiment mainly includes a first pole case 1, a second pole case 2, and a sealing ring 3. The openings of the first pole case 1 and the second pole case 2 are connected to each other to form a chamber for accommodating the battery cell. The first pole case 1 and the second pole case 2 are electrically connected to the negative electrode and the positive electrode of the battery cell, respectively. The first top cover 11 and the second top cover 21 serve as the negative electrode and the positive electrode of the button-type lithium-ion battery, respectively. The sealing ring 3 is connected between the first pole case 1 and the second pole case 2 to seal the gap between the first pole case 1 and the second pole case 2, thereby achieving sealing of the battery cell and providing insulation isolation for the positive and negative electrodes of the button-type lithium-ion battery.

[0078] The present invention illustrates that the first pole shell 1 is connected to the negative electrode of the battery cell as the first pole shell 1 is sleeved on the inner layer, and the second pole shell 2 is connected to the positive electrode of the battery cell as the second pole shell 2 is sleeved on the outer layer, but it is not limited to this.

[0079] The first pole housing 1 is an integrated structure, comprising a first top cover 11 and a first housing wall 12. The first housing wall 12 surrounds the edge of the first top cover 11 and is located on one side of the first top cover 11. It is perpendicular to the first top cover 11, forming a semi-enclosed housing with one axial end being open and the other end being the first top cover 11.

[0080] The preparation process of the first pole case 1 is as follows: a first metal sheet (preferably but not limited to a steel sheet) is placed in a stamping device, and the first metal sheet is stamped using a stamping die. When the stamping die is pressed down, the first pole case 1 is stamped on the first metal sheet. The first top cover 11 is located at the bottom of the stamping die, and the first shell wall 12 is formed around the edge of the first top cover 11 and around the axial periphery of the stamping die. Along the axial direction of the first shell wall 12, the outer diameter of the first shell wall 12 changes in multiple steps.

[0081] That is, along the axial direction of the first shell wall 12 from the first top cover 11 to the opening direction of the first pole shell 1, it is divided into: a first cylindrical ring segment 121 and a second cylindrical ring segment 122. The first cylindrical ring segment 121 and the second cylindrical ring segment 122 are bent between them to form a first outward convex ring segment 131.

[0082] The outer diameter of the first cylindrical ring segment 121 is smaller than that of the second cylindrical ring segment 122, with the difference being approximately 0.1 mm to 1 mm, for example, but not limited to, 0.4 mm. The outer diameter of the first convex ring segment 131 gradually widens along the axial direction from the first top cover 11 to the opening of the first pole housing 1. The outer diameter is narrowest at its junction with the first cylindrical ring segment 121, equal to that of the first cylindrical ring segment 121; it is widest at its junction with the second cylindrical ring segment 122, equal to that of the second cylindrical ring segment 122. The first convex ring segment 131 is bent in an R-shaped manner, forming a slightly flat platform protruding outward between the first and second cylindrical ring segments 121, 122. The radial width of the edge of the first convex ring segment 131 protruding radially outside the first cylindrical ring segment 121 (the radial width of the platform) is approximately 0.05 mm to 0.5 mm, for example, but not limited to, 0.4 mm.

[0083] When sealing the second shell wall 22, this embodiment not only applies a radially inward force to the second shell wall 22, but also applies downward pressure to the first outer protruding ring segment 131 while pressing the second shell wall 22 inward. This compresses the second shell wall 22 tightly against the first outer protruding ring segment 131. The first outer protruding ring segment 131 provides a radial support for pressing the second shell wall 22, thereby improving the sealing performance of the second shell wall 22. Furthermore, because the first outer protruding ring segment 131 adopts a variable diameter structure, it is less prone to radial deformation, which further improves the sealing performance of the button-type lithium-ion battery after storage or cycling.

[0084] The second pole shell 2 is an integrated structure, including a second top cover 21 and a second shell wall 22. The second shell wall 22 surrounds the edge of the second top cover 21, is located on one side of the second top cover 21, and is perpendicular to the second top cover 21, forming a semi-enclosed shell with one axial end being open and the other end being the second top cover 21.

[0085] The second electrode housing 2 can be manufactured using, but is not limited to, conventional techniques. It can be formed using, but is not limited to, a stamping process. The second housing wall 22 can be cylindrical with a consistent inner and outer diameters. During sealing, the second housing wall 22 is clamped around the sealing ring 3 outside the first housing wall 12, compressing the sealing ring 3 to seal the button-type lithium-ion battery housing. After being clamped, the second housing wall 22 has the same shape as the first housing wall 12.

[0086] The sealing ring 3 is coaxial with the first pole housing 1 and the second pole housing 2. The sealing ring 3 is tightly fitted on the first pole housing 1. The flange at the end of the sealing ring 3 is tightly fitted on the end face of the opening of the first housing wall 12. The main body of the sealing ring 3 is tightly fitted on the outer wall of the first housing wall 12 until it approaches or reaches the first top cover 11 (does not cover the first top cover 11). The end of the sealing ring 3 close to the end of the first top cover 11 is tightly fitted on the first housing wall 12. The end of the sealing ring 3 is recorded as the sealing position.

[0087] During assembly, the sealing ring 3 is put on the first pole shell 1, and then the battery cell is placed in the first pole shell 1. The positive and negative electrodes of the battery cell are electrically connected to the first pole shell 1 and the second pole shell 2 respectively to achieve electrode connection. The first pole shell 1 serves as the negative electrode of the button battery, and the second pole shell 2 serves as the positive electrode.

[0088] Then, the electrolyte injection, shell sealing and other processes are completed according to the existing technology to obtain a button-type lithium-ion battery.

[0089] In the housing sealing process of this embodiment, the openings of the first and second pole housings 1 and 2 are nested relative to each other, the second housing wall 22 is nested within the first housing wall 12, and the nested first and second pole housings 1 and 2 are advanced, bringing the first and second top covers 11 and 21 toward each other until they are fully nested. Then, using housing sealing technology, a sealing device is used to press the second housing wall 22, located outside the sealing ring section of the first housing wall 12, inward. The second housing wall 22 is deformed and pressed against the outside of the first housing wall 12, and the sealing ring 3 between the first and second housing walls 12 and 22 is firmly compressed, completely sealing the housing.

[0090] As can be seen from the above, the technical solution of this embodiment, due to the multi-stage stepped outer diameter of the button-type lithium-ion battery casing, is adopted. Multiple cylindrical ring segments are provided along the axial direction on the inner first shell wall 12, with radially protruding outer ring segments provided between each two cylindrical ring segments. This allows the sealing of the second shell wall 22. In addition to the radially inward force exerted on the second shell wall 22, the outer portion of the second shell wall 22 is also compressed inwardly. This also applies downward pressure to the first outer ring segment 131, pressing the second shell wall 22 tightly against the first outer ring segment 131. The first outer ring segment 131 provides a radial support for the compression of the second shell wall 22, thereby improving the sealing performance of the second shell wall 22. Furthermore, the variable diameter structure of the first outer ring segment 131 makes it less susceptible to radial deformation, further enhancing the sealing performance of the button-type lithium-ion battery after storage or cycling.

[0091] Moreover, in this embodiment, the outer diameter of the first shell wall 12 changes in a single direction from the first top cover 11 to the opening, that is, from narrow to wide, which can be achieved by stamping. The processing technology is simple, the processing cost is low, and it is not easy to deform after processing.

[0092] Example 2.

[0093] See also Figure 5-7 As shown,

[0094] The button-type lithium-ion battery of this embodiment differs from that of Example 1 mainly in that:

[0095] In this embodiment, the outer diameter of the first pole housing 1 adopts a three-stage gradient change structure, and the sealing ring section on the first pole housing 1 is divided into three sections. The specific structure is as follows.

[0096] The sealing ring segment of the first pole housing 1 is divided into: a first cylindrical ring segment 121, a second cylindrical ring segment 122 and a third cylindrical ring segment 123 along the axial direction from the first top cover 11 to the opening direction of the first pole housing 1. The first cylindrical ring segment 121 and the second cylindrical ring segment 122 are formed by bending to form a first outward convex ring segment 131, and the second cylindrical ring segment 122 and the third cylindrical ring segment 123 are formed by bending to form a second outward convex ring segment 132.

[0097] As can be seen from the figure, the outer diameter of the first cylindrical ring segment 121 is smaller than the outer diameter of the second cylindrical ring segment 122, with the difference being approximately 0.1mm to 1mm, such as, but not limited to, 0.4mm. The outer diameter of the first outer convex ring segment 131 at its narrowest point is equal to the outer diameter of the first cylindrical ring segment 121, and the outer diameter at its widest point is equal to the outer diameter of the second cylindrical ring segment 122. The first outer convex ring segment 131 is bent in an R-shaped manner, forming a slightly flat platform protruding outward between the first and second cylindrical ring segments 121, 122. The width of the radial edge of the first outer convex ring segment 131 protruding radially outside the first cylindrical ring segment 121 (the radial width of the platform) is approximately 0.05mm to 0.5mm, such as, but not limited to, 0.2mm.

[0098] The outer diameter of the second cylindrical ring segment 122 is smaller than the outer diameter of the third cylindrical ring segment 123, with the difference being approximately 0.1 mm to 1 mm, such as, but not limited to, 0.4 mm. The outer diameter of the second outer convex ring segment 132 at its narrowest point is equal to the outer diameter of the second cylindrical ring end, and the outer diameter at its widest point is equal to the outer diameter of the third cylindrical ring segment 123. The second outer convex ring segment 132 is bent in an R-shaped manner, forming a slightly flat platform protruding outward between the second and third cylindrical ring segments 122, 123. The width of the radial edge of the second outer convex ring segment 132 protruding radially outside the second cylindrical ring segment 122 (the radial width of the platform) is approximately 0.05 mm to 0.5 mm, such as, but not limited to, 0.2 mm.

[0099] The manufacturing process of this embodiment differs from that of Example 1 in that, when the second shell wall 22 at the periphery is pressed inward, downward pressure is applied to the first and second outer convex ring segments 131, 132, respectively, pressing the second shell wall 22 tightly against the first and second outer convex ring segments 131, 132. The first and second outer convex ring segments 131, 132 provide radial support for the compression, improving the sealing performance. Furthermore, because the first and second outer convex ring segments 131, 132 utilize a variable diameter structure, they are less prone to radial deformation, further improving the sealing performance of the button-type lithium-ion battery after storage or cycling.

[0100] In this embodiment, by providing multiple outward convex ring segments, the axial width of each cylindrical ring segment is greatly shortened, the strength is greatly improved and it is not easy to deform, which is more conducive to the thinning design of the shell. In addition, in this embodiment, the radial outward convex width of each outward convex ring segment can be set narrower, thereby ensuring the volume for accommodating the battery cell in the shell, which is conducive to increasing the capacity of the button-type lithium-ion battery.

[0101] Example 3.

[0102] See also Figure 8-10 As shown,

[0103] The button-type lithium-ion battery of this embodiment differs from that of Example 2 mainly in that:

[0104] The outer wall of the sealing ring 3 of this embodiment is further provided with an annular boss 31 protruding from the outer wall and a groove 32 recessed inwardly relative to the outer wall of the sealing ring 3 , wherein the annular boss 31 is coaxial with the sealing ring 3 and surrounds the outer circumference of the sealing ring 3 .

[0105] The top end of the groove 32 is non-through, and the top end of the groove 32 is located below the annular boss 31. The groove 32 extends from top to bottom along the outer wall of the sealing ring 3 to the bottom of the sealing ring 3, and the bottom open end is an open slot that penetrates downward, so that the electrolyte injected from the upper part of the groove 32 can flow out from the bottom slot.

[0106] Accordingly, the manufacturing process of the button-type lithium-ion battery of this embodiment is adaptively adjusted as follows:

[0107] Before injecting liquid, the openings of the first and second pole shells 1 and 2 are relatively nested, and the second shell wall 22 is nested in the first shell wall 12. The nested first and second pole shells 1 and 2 are pushed forward, so that the first top cover 11 and the second top cover 21 are close to each other, and the annular boss 31 of the first shell wall 12 is not nested in the second shell wall 22 but is located outside the second shell wall 22, and the portion of the groove 32 close to the annular boss 31 is not nested in the second wall but is located outside the second shell wall 22. Then, the advancement is stopped. In a low dew point environment, a predetermined amount of electrolyte is poured into the groove 32 exposed outside the second shell wall 22. The poured electrolyte flows down along the groove 32 and out of the notch located in the opening of the first pole shell 1 and enters the chamber between the first pole shell 1 and the second pole shell 2. The battery cell absorbs the electrolyte, and the injection is completed.

[0108] The specific liquid injection process can be but not limited to the existing technology.

[0109] After the liquid injection is completed, the first pole shell 1 and the second pole shell 2 are further connected until the two are completely connected. When they are completely connected, the groove 32 on the sealing ring 3 is completely inserted between the first shell wall 12 and the second shell wall 22, and all or part of the annular boss 31 is completely inserted into the second shell wall 22. The annular boss 31 of the sealing ring 3 between the first shell wall 12 and the second shell wall 22 is in a tense and compressed state. The annular boss 31 seals the gap between the first shell wall 12 and the second shell wall 22, and the first pole shell 1 and the second pole shell 2 seal the battery cell located therebetween.

[0110] In order to further improve the sealing performance of the button-type lithium-ion battery, a sealing position is further provided on the sealing ring 3. Specifically, the inner diameter of the annular segment at the very end of the sealing ring 3 close to the first top cover 11 is made smaller than the background of the sealing ring 3, so that the very end of the sealing ring 3 is relatively more tightly wrapped around the first pole shell 1.

[0111] As can be seen from the above, compared to the existing technology that keeps the opening of the first pole shell 1 open for liquid injection before fastening the two pole shells, the process of this embodiment maintains the fastening state after the first shell wall 12 and the second shell wall 22 are connected to a certain extent, and then injects liquid from the groove 33 of the exposed sealing ring 3. This avoids the problem of the existing liquid injection operation moving the pole shell and pulling the battery cell tab, which may cause the tab to break and thus lead to product defects. The technical solution of this embodiment improves the convenience of button-type lithium-ion battery injection and realizes quantitative liquid injection of batch button-type lithium-ion batteries, which is conducive to improving batch consistency, enhancing battery performance, and increasing the qualified rate.

[0112] As an illustration of this embodiment, the groove 32 provided on the outer wall of the sealing ring 3 can be as follows: Figure 1-8 The figure shows only one; there may also be multiple grooves 32, which are evenly distributed on the outer wall of the sealing ring 3 along the outer periphery thereof, without specific limitation.

[0113] As an illustration of this embodiment, the depth of the groove 32 provided on the outer wall of the sealing ring 3 may be, but is not limited to, about 1 / 2 of the wall thickness of the sealing ring 3 at the location of the groove 32 .

[0114] As an illustration of this embodiment, referring to the drawings of this embodiment, each groove 32 preferably extends linearly on the outer wall of the sealing ring 3 parallel to the axial direction of the sealing ring 3 to the opening of the first pole housing 1. However, this is not limiting, and each groove 32 can also be arranged on the outer wall of the sealing ring 3 in a circuitous or spiral shape.

[0115] As an illustration of this embodiment, the protrusion height of the annular boss 31 of the sealing ring 3 of this embodiment relative to the outer wall of the sealing ring 3 is about 0.01mm-0.2mm, for example but not limited to about 0.05mm-0.1mm higher than the outer wall of the sealing ring 3.

[0116] As an illustration of this embodiment, the axial distance between the groove 32 on the outer wall of the sealing ring 3 of this embodiment and the end of the sealing ring 3 close to the first top cover 11 (also known as the sealing position) is greater than 0.5 mm, so as to reserve a wide enough position for the axial width of the annular boss 31, so that the axial width of the annular boss 31 is between 0.1 mm and 0.5 mm, so as to ensure the sealing of the button battery.

[0117] Example 4.

[0118] See also Figure 11 shown.

[0119] As an illustration of this embodiment, this embodiment further provides a design scheme for the second pole housing 2. In this embodiment, the wall thickness of the first cylindrical ring segment 221 on the opening side of the second housing wall 22 is thicker than the wall thickness of the ring segment between the first cylindrical ring segment 221 and the second top cover 21. During sealing, the first cylindrical ring segment 221 of the second housing wall 22 is tightly pressed against the first outer protruding ring segment 131 of the first housing wall 12 and is in contact with the first outer protruding ring segment 131. The annular boss 31 of the sealing ring 3 is tightly clamped between the first cylindrical ring segment 221 of the second pole housing 2 and the first outer protruding ring segment 131 of the first pole housing 1.

[0120] As an illustration of this embodiment, the inner wall of the second shell wall 22 is designed to have the same outer diameter structure, so that the outer periphery of the button battery is smooth; the inner diameter of the first cylindrical ring segment 221 is designed to be smaller than the inner diameter of the ring segment from the first cylindrical ring segment 221 to the second top cover 21, so that its inner wall is relatively convex inward, so that the gap between the first shell wall 121 and the second shell wall 222 is narrowed at the position of the first cylindrical ring segment 221 of the second shell wall 22. The use of this structure is conducive to further strengthening the compression strength of the second shell wall 22 on the sealing ring 3 in its first cylindrical ring segment 221, thereby improving the sealing performance.

[0121] As an illustration of this embodiment, the wall thickness of the first cylindrical ring segment 221 of the second shell wall 22 of this embodiment is preferably, but not limited to, 0.15 mm to 0.25 mm; the wall thickness of other positions of the second shell wall 22 except the first cylindrical ring segment 221 can be, but not limited to, 0.05 mm to 0.15 mm.

[0122] Because this embodiment thickens the wall thickness of the first cylindrical ring segment 221 with a very narrow radial width located at the open end of the second shell wall 22, the rigidity and deformation resistance of the first cylindrical ring segment 221 of the second shell wall 22 are ensured, and the second shell wall 22 is firmly pressed against the sealing ring 3 outside the first shell wall 121, thereby ensuring the sealing of the shell, and avoiding the deformation of the shell due to the expansion force generated during the battery charging and discharging process, which in turn causes the annular seal to loosen, thereby affecting the airtightness of the shell and causing leakage. Based on the thickening design of the first cylindrical ring segment 221 of the second shell wall 22, this embodiment thins the wall thickness of other positions of the second pole shell 2, thereby leaving more cavity space for accommodating the battery cells and increasing the capacity of the button-type lithium-ion battery. In summary, by adopting this embodiment, the capacity of the button-type lithium-ion battery is increased while ensuring the sealing strength of the shell, solving the problem of limited capacity of the button-type lithium-ion battery in the prior art.

[0123] As an illustration of this embodiment, the axial width of the first cylindrical ring segment 221 at the open end of the second pole housing 2 is designed to be ultra-narrow. When in an unbent state, the axial width of the first cylindrical ring segment 221 is denoted by A. A can be, but is not limited to, a value greater than or equal to 0.2 mm and less than or equal to 1 mm. In a specific design, if the current button-type lithium-ion battery is smaller, the value A can be set to a smaller value within this range; if the current button-type lithium-ion battery is larger, the value A can be set to a larger value within this range to enhance the strength of the annular seal of the housing and improve the sealing strength of the housing.

[0124] As an illustration of this embodiment, the wall thickness of the first pole housing 1 of this embodiment is preferably but not limited to an ultra-thin design, for example but not limited to designing the wall thickness of the first pole housing 1 to be 0.05mm~0.15mm, which is lower than the lower limit of 0.2mm required in the prior art.

[0125] As an illustration of this embodiment, the wall thickness of the outer convex ring section of the first pole housing 1 near the first top cover 11 can also be increased, but is not limited to this. This outer wall of the outer convex ring section is flush with the outer walls of the rest of the first pole housing 1, while the inner wall is raised inward. As an illustration of this embodiment, the wall thickness of the outer convex ring section of the first pole housing 1 near the first top cover 11 is preferably, but not limited to, designed to be 0.15 mm to 0.25 mm.

[0126] See also Figure 11As shown, as an illustration of this embodiment, it is also preferred, but not limited to, to thicken the wall thickness from the outer convex ring section near the first top cover 11 to the first top cover 11 (including the first top cover 11), so that the wall thickness is consistent with the wall thickness of the outer convex ring section near the first top cover 11, and the inner and outer walls are both flush with the outer convex ring section near the first top cover 11. Accordingly, the wall thickness of the first pole housing 1 near the opening is designed to be ultra-thin, preferably, but not limited to, 0.05mm to 0.15mm, which is lower than the lower limit of 0.2mm required in the prior art.

[0127] As an illustration of this embodiment, the first top cover 11 and the second top cover 21 of this embodiment are respectively circular, forming a cylindrical button-type lithium-ion battery.

[0128] Comparative analysis of test data:

[0129] To further facilitate understanding of the technical solutions and effects of the embodiments of the present invention, a button-type lithium-ion battery of 1654 is used as an example below, where the outer diameter of the button-type lithium-ion battery at its widest point is 16 mm and the axial thickness of the button-type lithium-ion battery is 5.4 mm.

[0130] Experimental Example 1:

[0131] Button lithium-ion battery structure see Figure 1-4 As shown, the wall thickness of the first pole housing 1 and the second pole housing 2 are both 0.2 mm, and the thickness of the sealing ring 3 is 0.25 mm.

[0132] The preparation process and specific structure are described in detail in Example 1.

[0133] Experimental Example 2:

[0134] Button lithium-ion battery structure see Figure 5-7 shown.

[0135] The same as Experimental Example 1, wherein the wall thickness of the first pole housing 1 and the second pole housing 2 are both 0.2 mm, and the thickness is 0.15 mm. The difference from Experimental Example 1 is that this embodiment is provided with two outer convex ring segments.

[0136] The preparation process and specific structure of the sample in this experimental example are described in detail in Example 2.

[0137] Experimental Example 3:

[0138] Button lithium-ion battery structure see Figure 8-10 shown.

[0139] The wall thickness of the first pole shell 1 and the second pole shell 2 are both 0.2 mm, and the thickness of the sealing ring 3 is 0.15 mm.

[0140] An annular boss 31 is provided on the opening side of the sealing ring 3 close to the second pole housing 2. The axial width of the annular boss 31 is 0.3 mm, and the thickness of the annular boss 31 protruding from the outer wall of the sealing ring 3 is 0.05 mm. A groove 32 is provided under the annular boss. The depth of the groove 32 is 0.1 mm. There is a certain distance between the groove and the annular boss, and the groove extends axially to the opening end of the first housing wall 12.

[0141] In this embodiment, the liquid is injected when the first pole shell 1 and the second pole shell 2 are sleeved into the groove.

[0142] The preparation process and specific structure are described in detail in Example 2.

[0143] Experimental Example 4:

[0144] Button lithium-ion battery structure see Figure 11 shown.

[0145] The main differences between this embodiment and Experimental Example 3 are:

[0146] The opening end of the second pole housing 2 facing the first convex ring segment 131 of the first pole housing 1 is a first cylindrical ring segment 221 , the wall thickness of the first cylindrical ring segment 221 is 0.25 mm, and the wall thickness of other positions of the second pole housing 2 is 0.1 mm.

[0147] The wall thickness of the first pole housing 1 from the first top cover 11 to the first outwardly protruding ring segment 131 (including the first outwardly protruding ring segment 131 ) is 0.25 mm, and the wall thickness of other positions of the first pole housing 1 is 0.1 mm.

[0148] The rest is the same as Experimental Example 3.

[0149] Experimental Example 5:

[0150] The button-type lithium-ion battery structure of Experimental Example 5 is shown in Figure 12 shown.

[0151] The wall thickness of the first pole shell 1 and the second pole shell 2 are both 0.2 mm, and the wall thickness is uniform everywhere.

[0152] The central portion of the first pole housing 1 in this experimental example forms an outwardly convex arc wall. However, during the trial production of this sample, the present inventors discovered that because the diameter of this arc portion gradually narrows and then narrows from the first top cover 11 to the opening, stamping this outwardly convex arc structure is impossible. In this experimental example, the cylindrical first pole housing 1 structure was first stamped out, and then the convex arc structure was tapped outward using a tapping device to obtain the first pole housing 1.

[0153] The battery cell is assembled into the first pole case 1, liquid is injected, the first pole case 1 and the second pole case 2 are assembled, and the second pole case 2 is pressed. During the experiment, the inventors found that the outward-convex arc-shaped structure of this experimental example, after being left at rest for a certain period of time and when the second pole case 2 is pressed, the convex arc structure shrinks inward to a certain extent to recover its deformation.

[0154] Sealing leakage limit test:

[0155] Experimental equipment: vacuum oven, electronic balance

[0156] The vacuum oven setting parameters are: vacuum degree -100Kpa, set temperature 60 degrees, and set shelf time 168h.

[0157] Test method:

[0158] Use an electronic balance to weigh the sample and record the weight W1;

[0159] Set aside in a vacuum oven;

[0160] After the shelf is completed, cool at room temperature for 2 to 4 hours;

[0161] Use an electronic balance to weigh the sample and record the weight W2;

[0162] Weight loss = W1-W2.

[0163] As an illustration of this embodiment, the first pole shell 1 and the second pole shell 2 are respectively steel shells, but they can also be, but are not limited to, other corrosion-resistant, rigid, and strong alloy materials.

[0164] According to the above test, the following data is obtained:

[0165] project weight loss Experimental Example 1 0.8mg Experimental Example 2 0.3mg Experimental Example 3 0.2mg Experimental Example 4 0.1mg Experimental Example 5 0.8mg

[0166] As can be seen from the above, the technical solution of this embodiment is beneficial to improving the sealing performance of the button-type lithium-ion battery.

[0167] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. A method for preparing a button-type lithium-ion battery, characterized in that: include: A first metal sheet is stamped to form a first pole housing, a first top cover, and a first housing wall surrounding the edge of the first top cover, wherein the first housing wall includes at least two cylindrical ring segments along the axial direction and each convex ring segment formed by bending between two adjacent cylindrical ring segments; each cylindrical ring segment has the same inner and outer diameters; any two cylindrical ring segments have different outer diameters; the outer diameter of the cylindrical ring segment near the first top cover is narrower than the outer diameter of the cylindrical ring segment near the opening of the first pole housing; and the outer diameter of each convex ring segment gradually narrows along the axial direction from the opening of the first pole housing toward the first top cover; stamping a second metal sheet to form a second pole shell, a second top cover, and a second shell wall surrounding an edge of the second top cover; A sealing ring is provided outside the first pole housing, and a raised annular boss and an inwardly recessed groove are further provided on the outer wall of the sealing ring. When the opening of the first pole housing faces downward, the groove is located below the annular boss and extends to the opening of the first pole housing. The inner wall of the sealing ring is tightly attached to the outer wall and the end face of the opening of the first housing wall. The annular boss is pressed tightly between the first housing wall and the second housing wall to seal the gap between the first housing wall and the second housing wall. The groove completely enters between the first housing wall and the second housing wall. A battery cell is placed in the first pole housing so that one of the positive and negative electrodes of the battery cell is electrically connected to the first pole housing, and the other is electrically connected to the second pole housing. The second pole shell is relative to the opening of the first pole shell, and the sleeve is sleeved until the annular boss is located outside the second shell wall and the groove is partially exposed outside the second shell wall. The sleeve is paused, and a predetermined amount of electrolyte is poured into the groove. The electrolyte flows along the groove into the cavity between the first pole shell and the second pole shell. The injection is completed. The first pole housing and the second pole housing are further sleeved until the groove completely enters between the first housing wall and the second housing wall, and the annular boss is pressed between the first housing wall and the second housing wall to seal the gap between the first housing wall and the second housing wall, and the first pole housing and the second pole housing are completely sleeved. The second shell wall is pressed tightly against the first shell wall to compress and seal the sealing ring.

2. A button-type lithium-ion battery, characterized in that: include: The first pole shell includes an integrally formed first top cover and a first shell wall. The first shell wall is located on one side of the first top cover and surrounds the edge of the first top cover. The first shell wall includes at least two cylindrical ring segments and each convex ring segment formed by bending between every two adjacent cylindrical ring segments. The inner and outer diameters of each cylindrical ring segment are the same, and the outer diameters of any two cylindrical ring segments are different. The outer diameter of the cylindrical ring segment close to the first top cover is narrower than the outer diameter of the cylindrical ring segment close to the opening of the first pole shell. Axially from the opening of the first pole shell to the first top cover, the outer diameter of each convex ring segment is smaller than that of the cylindrical ring segment close to the opening of the first pole shell. The outer diameter gradually narrows, and the sealing ring is tightly sleeved on the first pole shell. The inner wall of the sealing ring is tightly attached to the outer wall and the end face of the opening of the first shell wall. A raised annular boss and an inwardly recessed groove are also provided on the outer wall of the sealing ring. The opening of the first pole shell is downward, and the groove is located below the annular boss. The groove extends to the opening position of the first pole shell. The annular boss is pressed between the first shell wall and the second shell wall to seal the gap between the first shell wall and the second shell wall. The groove completely enters between the first shell wall and the second shell wall. The second pole housing includes an integrally formed second top cover and a second housing wall. The second housing wall surrounds the edge of the second top cover, is perpendicular to the second top cover, and is located on one side of the second top cover. The openings of the first and second pole shells are relatively sleeved, the second shell wall is tightly sleeved outside the first shell wall, and the inner diameter and outer diameter of the sealing ring segment are narrowed from the opening of the first pole shell to the first top cover in the axial direction, and the sealing ring is spaced between the first and second pole shells; The first top cover and the second top cover are respectively located at the axial ends of the first shell wall and the second shell wall which are connected to each other, and the first pole shell and the second pole shell form a sealed chamber; A battery cell, comprising a positive electrode sheet, a negative electrode sheet, and a separator, wherein the separator is spaced between any adjacent positive and negative electrode sheets, and one of the positive electrode and the negative electrode of the battery cell is electrically connected to the first electrode shell, and the other is electrically connected to the second electrode shell; The electrolyte is immersed in the battery core, and the battery core and the electrolyte are encapsulated in the chamber.

3. The button-type lithium-ion battery according to claim 2, wherein: The sealing ring segment includes: at least three cylindrical ring segments, and each of the outer convex ring segments formed by bending and located between each two adjacent cylindrical ring segments; The difference in outer diameters of the two cylindrical ring segments located at two axial ends of any one of the outer convex ring segments is 0.1 mm to 1 mm.

4. The button-type lithium-ion battery according to claim 3, wherein: The radial protrusion width of any of the outer protruding ring segments is 0.05 mm to 0.5 mm.

5. The button-type lithium-ion battery according to claim 2, wherein: At least two grooves are provided on the outer wall of the sealing ring.

6. The button-type lithium-ion battery according to claim 5, wherein: The grooves are distributed around the outer wall of the sealing ring.

7. The button-type lithium-ion battery according to claim 2, wherein: Each of the grooves is parallel to the axial direction of the sealing ring.

8. The button-type lithium-ion battery according to claim 2, wherein: The axial width of the annular boss is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

9. The button-type lithium-ion battery according to claim 2, wherein: The depth of the groove is 1 / 2 of the thickness of the first shell wall where the groove is located.

10. The button-type lithium-ion battery according to claim 2, wherein: The wall thickness of the first cylindrical ring segment of the second shell wall at the end of the opening side is greater than the wall thickness of the ring segment between the first cylindrical ring segment and the second top cover; The first cylindrical ring segment of the second shell wall is tightly pressed against the outside of the sealing ring outside the outer convex ring segment close to the first top cover.

11. The button-type lithium-ion battery according to claim 10, wherein: The outer diameters of the second shell wall are consistent, and the inner diameter of the first cylindrical ring segment of the second shell wall is smaller than the inner diameter of the ring segment between the first cylindrical segment and the second top cover.

12. The button-type lithium-ion battery according to claim 10, wherein: The wall thickness of the first cylindrical ring segment of the second shell wall is greater than or equal to 0.15 mm and less than or equal to 0.25 mm.

13. The button-type lithium-ion battery according to claim 10, wherein: Except for the first cylindrical ring segment, the wall thickness of the second shell wall is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

14. The button-type lithium-ion battery according to claim 10, wherein: The wall thickness of the outwardly protruding ring segment of the first shell wall close to the first top cover is greater than the wall thickness of the ring segment between the outwardly protruding ring segment and the opening of the first pole shell.

15. The button-type lithium-ion battery according to claim 14, wherein: The outer convex ring segment of the first shell wall close to the first top cover, the first top cover, and the wall thickness from the first top cover to the outer convex ring segment are consistent.

16. The button-type lithium-ion battery according to claim 14, wherein: The wall thickness of the outer convex ring segment of the first shell wall close to the first top cover is greater than or equal to 0.15 mm and less than or equal to 0.25 mm.

17. The button-type lithium-ion battery according to claim 16, wherein: The wall thickness of the ring segment of the first shell wall from the outwardly protruding ring segment close to the first top cover to the opening of the first shell wall is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

18. The button-type lithium-ion battery according to claim 2, wherein: The first pole shell and the second pole shell are respectively steel shells.

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