Packaging process, shell and packaging fixing jig of button lithium ion battery

Abstract

This application provides a packaging process, casing, and packaging fixture for a button lithium-ion battery, including: stamping the casing: the casing includes upper and lower cover pits, upper and lower cover packaging skirts, and an airbag. The upper and lower cover pits are located on both sides of the airbag, and four sets of positioning holes are stamped along their circumference and close to the upper and lower cover pits; installing the battery cell: the battery cell is installed in the lower cover pit, and the positive and negative terminals are electrically connected to the battery cell; closing: the casing is folded in half along the symmetrical axis of the upper and lower cover pits to close the upper and lower cover pits, and the positioning holes of the positioning hole sets are aligned one by one to align the upper and lower cover packaging skirts; fixing with the upper fixture: the closed casing and the battery cell are fixed on the packaging fixture, and the positioning pins on it are used to engage through the positioning hole sets; packaging: the packaging fixture with the closed casing fixed is fixed on the packaging mold head, and the closed casing is packaged on it. This application improves the packaging accuracy by aligning the upper and lower cover packaging skirts through the positioning hole sets.

Description

Technical Field

[0001] This application relates to the field of battery packaging technology, specifically to a packaging process for a button lithium-ion battery, and also to a casing and a packaging fixture. Background Technology

[0002] With the increasing market demand for portable micro electronic devices, such as wireless Bluetooth headsets and smart glasses, the performance and size requirements for their supporting micro power supplies are becoming increasingly stringent. Among the many micro power supply solutions, button-type lithium-ion batteries have become one of the most widely used technologies due to their small size and high energy density.

[0003] To continuously improve battery energy density, maximizing the utilization of internal battery space is crucial. Currently, conventional button-type lithium-ion batteries mostly use steel casings. However, steel casings have inherent thickness and molding limitations, resulting in low internal space utilization and making it difficult to meet the demands of high energy density development. Therefore, the industry has shifted towards developing button-type lithium-ion batteries using thinner aluminum-plastic encapsulation materials. Nevertheless, these button-type lithium-ion batteries, especially their encapsulation process, still face significant challenges. Encapsulation quality directly determines the battery's electrolyte retention capacity, internal pressure tolerance, and long-term cycle stability, thus decisively impacting the battery's overall performance, energy density, and safety.

[0004] Therefore, there is a need to provide a packaging process for button lithium-ion batteries to solve the technical problems that restrict production efficiency of existing button lithium-ion batteries due to poor control of packaging precision and complex packaging processes (such as the need for multiple packaging). Summary of the Invention

[0005] This application provides a packaging process for button lithium-ion batteries to solve the technical problems that limit production efficiency of existing button lithium-ion batteries due to poor packaging precision control and complex packaging processes (such as requiring multiple packaging steps). This application also provides a housing and a packaging fixture.

[0006] This application provides a packaging process for a button lithium-ion battery, including: Stamped housing: The stamped housing includes: an upper cover recess, a lower cover recess, an upper cover sealing skirt, a lower cover sealing skirt, and an airbag. The upper cover recess and the lower cover recess are located on opposite sides of the airbag, and four sets of positioning holes are symmetrically stamped along the circumference of the airbag and close to the upper cover recess and the lower cover recess. The positioning hole sets are a first positioning hole, a second positioning hole, and a third positioning hole arranged in an array. Install the battery cell: Install the battery cell in the lower cover pit and electrically connect the positive and negative tabs to the battery cell; Closing: The housing is folded along the axis of symmetry of the upper cover pit and the lower cover pit. After folding, the upper cover pit and the lower cover pit are closed, and the positioning hole group on one side of the upper cover pit and the positioning hole group on one side of the lower cover pit are aligned with each other, so that the upper cover encapsulation skirt and the lower cover encapsulation skirt are in a mutually aligned position. Upper fixture fixation: The covered housing together with the battery cell encapsulated therein is fixed on the packaging fixture, wherein the covered housing is fixed on the packaging fixture by the positioning pin group corresponding to the positioning hole group through the positioning hole group. Encapsulation: The encapsulation fixture, which has the covered housing, is fixed on the encapsulation mold head, and the covered housing is encapsulated on the encapsulation mold head.

[0007] Optionally, the diameter of the first positioning hole is equal to the diameter of the second positioning hole, and the diameter of the third positioning hole is smaller than the diameters of the first positioning hole and the second positioning hole.

[0008] Optionally, the package includes: First sealing: The side sealing area and top sealing area of ​​the closed shell are simultaneously sealed for the first time; Second sealing: A second sealing is performed at a predetermined distance from the liquid injection hole at the center of the housing; Resealing: Resealing the unsealed area in the top sealing area.

[0009] Optionally, during the first encapsulation, an arc shape is formed at the junction of the encapsulation areas of the side sealing area and the top sealing area, and the central angle corresponding to the arc shape is 20° to 60°. The arc shape is used to reduce the area of ​​the overlapping region between the re-sealing and the top sealing area of ​​the first encapsulation.

[0010] Optionally, prior to the second encapsulation, electrolyte is injected through the injection hole, and the electrolyte enters the cell through the unencapsulated area in the top sealing region for formation and venting.

[0011] Optionally, the width of the resealed package is greater than the width of the top sealing area of ​​the first package, and the central angle corresponding to the resealed area is 30° to 60°.

[0012] Optionally, after encapsulation, the shell is trimmed to remove the area where the width of the re-sealed encapsulation is greater than the width of the top sealing area of ​​the first encapsulation, in order to form a button lithium-ion battery.

[0013] Optionally, the packaging fixture is further provided with a cell support and fixing platform, positive and negative electrode tab slots, and a fixing slot to fix the closed housing together with the cell enclosed therein onto the packaging fixture. The cell support and fixing platform is used to install the closed housing together with the cell enclosed therein, the positive and negative electrode tab slots are used to install the positive and negative electrodes, and the fixing slot is used to fix the packaging fixture onto the packaging mold head.

[0014] Optionally, the positive and negative tabs are distributed at 90° or 180°.

[0015] This application also provides a housing for mounting a cell in the packaging process of a button lithium-ion battery; The housing includes: an upper cover pit, a lower cover pit, an upper cover sealing skirt, a lower cover sealing skirt, and an airbag. The upper cover pit and the lower cover pit are respectively located on opposite sides of the airbag. The battery cell is installed in the lower cover pit, and the positive and negative terminals are electrically connected to the battery cell. Four sets of positioning holes are symmetrically arranged along the circumference of the airbag and close to the upper cover pit and the lower cover pit, respectively. The positioning hole sets are a first positioning hole, a second positioning hole, and a third positioning hole arranged in an array.

[0016] Optionally, the diameter of the first positioning hole is equal to the diameter of the second positioning hole, and the diameter of the third positioning hole is smaller than the diameters of the first positioning hole and the second positioning hole.

[0017] This application also provides a packaging and fixing fixture for fixing the casing and the cell in the packaging process of a button lithium-ion battery; The packaging and fixing fixture includes: a cell support and fixing platform, positive and negative electrode ear slots, a fixing slot, and a positioning pin group; the cell support and fixing platform is used to install the covered housing together with the cell enclosed therein, the positioning pin group passes through the corresponding positioning hole group and engages, the positive and negative electrode ear slots are used to install the positive and negative electrodes to fix the covered housing together with the cell enclosed therein on the packaging and fixing fixture, and the fixing slot is used to fix the packaging and fixing fixture with the covered housing fixed on the packaging mold head.

[0018] Compared with the prior art, this application has the following advantages: This application provides a packaging process for a button lithium-ion battery, comprising: stamping a housing: the stamped housing includes an upper cover recess, a lower cover recess, an upper cover packaging skirt, a lower cover packaging skirt, and an airbag. The upper cover recess and the lower cover recess are located on opposite sides of the airbag, and four sets of positioning holes are symmetrically stamped along the circumference of the airbag and close to the upper cover recess and the lower cover recess, respectively. The positioning hole sets are a first positioning hole, a second positioning hole, and a third positioning hole arranged in an array; installing a battery cell: installing the battery cell in the lower cover recess and electrically connecting the positive and negative terminals to the battery cell; closing: folding the housing along the axis of symmetry of the upper cover recess and the lower cover recess. After folding, the upper cover recess... The upper cover is closed with the lower cover pit, and the positioning holes on one side of the upper cover pit and the positioning holes on one side of the lower cover pit are aligned one by one, so that the upper cover packaging skirt and the lower cover packaging skirt are in a mutually aligned position; Upper fixture fixing: The closed shell together with the battery cell encapsulated therein is fixed on the packaging fixing fixture, wherein the positioning pins set on the packaging fixing fixture corresponding to the positioning hole group pass through the positioning hole group and engage, so that the closed shell is fixed on the packaging fixing fixture; Packaging: The packaging fixing fixture with the closed shell is fixed on the packaging mold head, and the closed shell is packaged on the packaging mold head.

[0019] This application provides a packaging process for a button lithium-ion battery. During the impact process, four sets of positioning holes are symmetrically stamped around the circumference of the airbag near the upper and lower cover pits. These positioning holes are arranged in an array: a first positioning hole, a second positioning hole, and a third positioning hole. During closing, the casing is folded along the axis of symmetry of the upper and lower cover pits. After folding, the upper and lower cover pits are closed, with each corresponding positioning hole on one side of the upper cover pit and the lower cover pit aligned one-to-one, ensuring the upper and lower cover packaging skirts are aligned. In other words, by aligning the first, second, and third positioning holes one-to-one during closing, the upper and lower cover packaging skirts are aligned, improving packaging accuracy and consistency. This also avoids cell surface contamination caused by misalignment of the upper and lower cover packaging skirts and improves packaging yield.

[0020] Furthermore, in a further preferred embodiment, the following technical features are adopted: the encapsulation includes: a first encapsulation: simultaneously performing a first encapsulation on the side sealing area and the top sealing area of ​​the capped housing; a second encapsulation: performing a second encapsulation at a preset distance from the liquid injection hole at the center of the housing; and a re-sealing: re-sealing the unencapsulated area in the top sealing area. The first encapsulation is an integrated encapsulation of the side sealing area and the top sealing area, which can improve the over-melting or insufficient melting at the interface of different shaped packages, reduce the number of encapsulation steps to simplify the encapsulation process, and improve the production efficiency of encapsulation.

[0021] Based on the above preferred embodiments, a further preferred embodiment provides the following technical feature: During the first encapsulation, an arc shape is formed at the junction of the side sealing area and the top sealing area. The central angle of the arc shape is 20° to 60°. The arc shape is used to reduce the area of ​​the overlap between the top sealing area of ​​the re-sealing and the first encapsulation. In other words, by reducing the area of ​​the overlap between the top sealing area of ​​the re-sealing and the first encapsulation, the arc shape can significantly improve the problem of defects at the junction, improve the wetting ability of the electrolyte, and reduce the risk of leakage at the junction. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the packaging of a button lithium-ion battery in the prior art.

[0023] Figure 2 This is a schematic diagram of the shell structure provided in this application.

[0024] Figure 3 This is a schematic diagram of the packaging of the button lithium-ion battery provided in this application.

[0025] Figure 4 yes Figure 3 A partial schematic diagram of the circular arc structure.

[0026] Figure 5 This is a schematic diagram of the packaging of a button lithium-ion battery (with edges cut) provided in this application.

[0027] Figure 6 This is a schematic diagram of the structure of the encapsulation and fixing fixture provided in this application.

[0028] Figure 7 This is a schematic diagram of the structure of the button lithium-ion battery provided in this application.

[0029] Figure label: Reference numerals in prior art drawings ( Figure 1 ): 1: Top seal; 2: Side seal; 3: Second pre-seal; 4: Third seal; 5: Final round arc seal; Reference numerals in other figures of this application ( Figures 2-7 ): 10: Housing; 101: Upper cover recess; 102: Lower cover recess; 103: Upper cover sealing skirt; 104: Lower cover sealing skirt; 105: Airbag; 106: Positioning hole group; 1061: First positioning hole; 1062: Second positioning hole; 1063: Third positioning hole; 107: Liquid injection hole; 20: Positive electrode; 30: Negative electrode; 40: Packaging and fixing fixture; 401: Positioning pin assembly; 4011: First positioning pin; 4012: Second positioning pin; 4013: Third positioning pin; 402: Cell support and fixing platform; 403: Positive electrode ear slot; 404: Negative electrode ear slot; 405: Fixing slot; 50: First encapsulation; 501: Arc shape; 502: Top seal area; 503: Side seal area; 60: Second encapsulation; 70: Re-encapsulation. Detailed Implementation

[0030] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0031] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] Among related technologies, button-type lithium-ion batteries, especially their packaging process, still face significant challenges. Packaging quality directly determines the battery's electrolyte retention capacity, internal pressure tolerance, and long-term cycle stability, thus having a decisive impact on the battery's overall performance, energy density, and safety.

[0034] Figure 1This is a schematic diagram of the packaging of a button lithium-ion battery in the prior art. In the prior art, the packaging process involves first sealing the arc-shaped area (1), then side sealing the airbag area (2), followed by a second pre-sealing of the airbag after electrolyte injection (3), and a third sealing (4) at the airbag after formation. This third sealing is only a temporary process; after sealing, the cell must immediately undergo a final arc-shaped seal (5) to complete the entire cell packaging. In the existing packaging process, a final arc-shaped seal (5) must be performed immediately after the third sealing (4) to prevent residual gas or electrolyte in the airbag from flowing back into the core mold cavity, which could cause the cell to bulge.

[0035] In existing packaging processes, the alignment of the upper and lower cover pits after folding is poor, resulting in poor packaging consistency. Furthermore, the repeated heat sealing in the overlapping areas of the top seal 1, side seal 2, and final arc seal 5 during the three-stage heat sealing process can lead to over-melting or poor melting of the aluminum-plastic film at the interface, easily causing electrolyte leakage during the final arc seal 5. Moreover, the significant heat radiation during the top seal 1 and side seal 2 packaging process during mass production can cause heat melting during the final arc seal 5, making it difficult for the electrolyte to enter the cylindrical mold cavity and affecting its wetting within the core.

[0036] To address the technical problems hindering production efficiency of existing button lithium-ion batteries due to poor packaging precision control and complex packaging processes (such as requiring multiple packaging steps), this application provides a packaging process for a button lithium-ion battery, comprising: stamping a casing: the stamped casing includes an upper cover pit, a lower cover pit, an upper cover packaging skirt, a lower cover packaging skirt, and an airbag. The upper cover pit and the lower cover pit are located on opposite sides of the airbag, and four sets of positioning holes are symmetrically stamped along the circumference of the airbag and close to the upper and lower cover pits, each set including a first positioning hole, a second positioning hole, and a third positioning hole, arranged in a triangular pattern; installing the battery cell: installing the battery cell in the lower cover pit and electrically connecting the positive and negative terminals to the battery cell; closing: folding the casing along the symmetrical axis of the upper and lower cover pits, after folding... The upper and lower cover pits are closed, and the positioning holes on one side of the upper cover pit and the positioning holes on one side of the lower cover pit are aligned one by one, so that the upper cover packaging skirt and the lower cover packaging skirt are in a mutually aligned position; Upper fixture fixing: The closed shell and the battery cell inside are fixed on the packaging fixing fixture, wherein the positioning pins set on the corresponding positioning hole group on the packaging fixing fixture pass through the positioning hole group and engage, so that the closed shell is fixed on the packaging fixing fixture; Packaging: The packaging fixing fixture with the closed shell is fixed on the packaging mold head, and the closed shell is packaged on the packaging mold head.

[0037] This application provides a packaging process for a button lithium-ion battery. During impact testing of the casing, four sets of positioning holes are symmetrically stamped around the circumference of the airbag, near the upper and lower cover pits. These positioning holes are arranged in an array of first, second, and third positioning holes, specifically in a triangular arrangement. During closing, the casing is folded along the axis of symmetry between the upper and lower cover pits. After folding, the upper and lower cover pits close together, with the positioning holes on one side of the upper cover pit and the lower cover pit aligned one-to-one, ensuring that the upper and lower cover sealing skirts are in a mutually aligned position. In other words, when the cover is closed, the first positioning hole, the second positioning hole, and the third positioning hole can be aligned one by one to ensure that the upper cover packaging skirt and the lower cover packaging skirt are in the same position, thereby improving the packaging accuracy. It can also avoid cell surface contamination caused by misalignment of the upper cover packaging skirt and the lower cover packaging skirt, and improve the packaging yield.

[0038] Next, the packaging process, casing, and packaging fixture of a button lithium-ion battery provided in this application will be described in detail with reference to the accompanying drawings.

[0039] Figure 2 This is a schematic diagram of the shell structure provided in this application. Figure 3 This is a schematic diagram of the packaging of the button lithium-ion battery provided in this application. Figure 4 yes Figure 3 A partial schematic diagram of the circular arc structure. Figure 5 This is a schematic diagram of the packaging of a button lithium-ion battery (with edges cut) provided in this application. Figure 6 This is a schematic diagram of the structure of the encapsulation and fixing fixture provided in this application. Figure 7 This is a schematic diagram of the structure of the button lithium-ion battery provided in this application.

[0040] This application provides a packaging process for a button-type lithium-ion battery. It should be noted that the button-type lithium-ion battery mentioned in this application refers to a soft-pack button-type lithium-ion battery, which will be simply referred to as a button-type lithium-ion battery in the following application. A soft-pack button-type lithium-ion battery (button-type lithium-ion battery) refers to a rechargeable lithium-ion battery that is packaged using aluminum-plastic composite film soft packaging technology and has a round, button-like shape. The term "button-type" mainly refers to its shape and installation method (embedded in a battery holder like a button). Its shape can be round, flat, etc., while "soft-pack" defines its fundamental technical approach and packaging structure.

[0041] This application provides a packaging process for a button lithium-ion battery, such as... Figure 2As shown, the stamped housing 10 includes: an upper cover recess 101, a lower cover recess 102, an upper cover encapsulation skirt 103, a lower cover encapsulation skirt 104, and an airbag 105. The upper cover recess 101 and the lower cover recess 102 are located on opposite sides of the airbag 105, and four sets of positioning holes 106 are symmetrically stamped along the circumference of the airbag 105 and close to the upper cover recess 101 and the lower cover recess 102. The positioning hole sets 106 are a first positioning hole 1061, a second positioning hole 1062, and a third positioning hole 1063 arranged in an array.

[0042] The packaging process begins with stamping, where a two-dimensional aluminum-plastic film is stamped to form an aluminum-plastic shell 10. This involves placing a roll of aluminum-plastic film into a precision stamping press, where the die moves and a "cold stamping drawing" process is used to stretch the two-dimensional aluminum-plastic film into a three-dimensional aluminum-plastic shell 10, featuring an upper cover recess 101, a lower cover recess 102, an upper cover sealing skirt 103, a lower cover sealing skirt 104, and an airbag 105. Since the precision stamping press and its working process are existing technologies and not the focus of this application, a detailed description of the precision stamping press is not provided here.

[0043] In this embodiment, both the upper cover pit 101 and the lower cover pit 102 are circular structures, and they are located on opposite left and right sides of the airbag 105, respectively. The depth of the lower cover pit 102 is greater than the depth of the upper cover pit 101, but their diameters are equal. The specific dimensions of the upper cover pit 101 and the lower cover pit 102 are not limited here and can be determined according to the specific working conditions. An upper cover encapsulation skirt 103 is formed at the edge of the upper cover pit 101, and a lower cover encapsulation skirt 104 is formed at the edge of the lower cover pit 102. It can be understood that the upper cover encapsulation skirt 103 and the lower cover encapsulation skirt 104 are arc structures with a certain width formed along the edges of the upper cover pit 101 and the lower cover pit 102, respectively. Specifically, the upper cover encapsulation skirt 103 is not formed at the edge of the upper cover pit 101 near the airbag, and similarly, the lower cover encapsulation skirt 104 is not formed at the edge of the lower cover pit 102 near the airbag. Moreover, the width of the upper cover encapsulation skirt 103 and the lower cover encapsulation skirt 104 are the same. The specific value of the width can be determined according to the specific working conditions.

[0044] Meanwhile, four sets of positioning holes 106 are formed circumferentially on the airbag 105. These four sets of positioning holes 106 have identical structures and are distributed along the circumference of the airbag 105, close to the upper cover pit 101 and the lower cover pit 102. Specifically, two sets of positioning holes 106 are located on one side of the upper cover pit 101, and are distributed along both the upper and lower sides of the upper cover pit 101. Similarly, the remaining two sets of positioning holes 106 are located on one side of the lower cover pit 102, and are distributed along both the upper and lower sides of the lower cover pit 102.

[0045] Furthermore, each group of positioning holes 106 consists of a first positioning hole 1061, a second positioning hole 1062, and a third positioning hole 1063 arranged in an array. Specifically, the positioning hole group 106 includes a first positioning hole 1061, a second positioning hole 1062, and a third positioning hole 1063, and the three are arranged in a triangular pattern. In the embodiment of this application, the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 are arranged in an isosceles triangle. For example, the distance between the third positioning hole 1063 and the left (right) side of the lower cover pit 102 is 2mm to 5mm (including the endpoint value), and the distance between the third positioning hole 1063 and the lower (upper) side of the lower cover pit 102 is 5mm to 10mm. The distance between the first positioning hole 1061 and the left (right) side of the lower cover pit 102 is 5mm to 10mm, and the distance between the first positioning hole 1061, the second positioning hole 1062 and the third positioning hole 1063 is 2mm to 5mm. Since the first positioning hole 1061, the second positioning hole 1062 and the third positioning hole 1063 are distributed in an isosceles triangle, the distance between the second positioning hole 1062 and the lower (upper) side and the left (right) side of the upper cover pit can be determined based on the distance between the third positioning hole 1063 and the first positioning hole 1061 and the lower (upper) side and the left (right) side of the upper cover pit. The left (right) side of the lower cover recess 102 is directly connected to the lower cover encapsulation skirt 104, and the lower (upper) side of the lower cover recess 102 is its upper and lower side.

[0046] The distribution of the remaining three groups of positioning holes 106 can be set as described above. Of course, the distances between the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 and the left (right) and bottom (top) sides of the lower cover pit 102 can be determined according to the specific working conditions, and are not limited here. Moreover, the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 can also be distributed in an equilateral triangle or a right triangle. They are not listed here, and can be determined according to the specific working conditions.

[0047] Furthermore, the diameter of the first positioning hole 1061 is equal to the diameter of the second positioning hole 1062, and the diameter of the third positioning hole 1063 is smaller than the diameter of the first positioning hole 1061 and the diameter of the second positioning hole 1062.

[0048] The first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 are circular. The third positioning hole 1063 is located on the left (right) side near the lower cover pit 102 or the upper cover pit 101. The diameter of the third positioning hole 1063 is smaller than the diameter of the first positioning hole 1061 and the diameter of the second positioning hole 1062, while the diameters of the first positioning hole 1061 and the second positioning hole 1062 are equal. Specifically, the diameter of the third positioning hole 1063 is less than or equal to half the diameter of the first positioning hole 1061 and the diameter of the second positioning hole 1062. A smaller diameter improves alignment accuracy and reduces dimensional deviations caused by an excessively large diameter. The "diameter" can refer to the diameter of the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063, or it can be the radius. Here, the distribution of the first positioning hole 1061, the second positioning hole 1062 and the third positioning hole 1063 and their specific diameters are not restricted, and can be determined according to the specific circumstances.

[0049] After the housing is formed by stamping, the next step is to install the battery cell on the housing. This involves installing the battery cell in the lower cover pit and electrically connecting the positive and negative tabs to the battery cell.

[0050] Because the depth of the lower cover pit is greater than that of the upper cover pit, it is beneficial to the stability of the core; and the air bladder is designed on one side of the upper cover pit to prevent deformation during sealing. Therefore, the battery cell is installed in the lower cover pit. Position the battery cell with the positive and negative tabs facing the lower cover pit, ensuring that the geometric center of the battery cell is initially aligned with the geometric center of the lower cover pit. Gently and smoothly insert the battery cell vertically into the lower cover pit. During operation, avoid any part of the battery cell (especially the sharp edges of the electrodes) from scratching or puncturing the aluminum-plastic film.

[0051] After the battery cell is embedded in the lower cover pit, it is also necessary to confirm that the battery cell is completely contained in the lower cover pit without any tilting or displacement.

[0052] Furthermore, the positive and negative electrodes are distributed at 90° or 180°. For example... Figure 3 As shown, the positive electrode tab 20 and the negative electrode tab 30 can be distributed at a 90° angle or at a 180° angle. Of course, it is also possible that the positive electrode tab 20 and the negative electrode tab 30 can be distributed at other angles, which will not be listed here.

[0053] like Figures 2-3 , Figure 5 and Figure 7As shown, after the above-mentioned battery cell installation is completed, the housing 10 needs to be covered next. That is, the upper cover pit 101 and the lower cover pit 102 of the housing 10 are folded in half along their symmetrical axes. After folding, the upper cover pit 101 and the lower cover pit 102 are covered, and the positioning hole group 106 on one side of the upper cover pit 101 and the positioning hole group 106 on one side of the lower cover pit 102 are aligned one by one, so that the upper cover encapsulation skirt 103 and the lower cover encapsulation skirt 104 are in a mutually aligned position.

[0054] Specifically, the housing 10 is folded along the axis of symmetry of the upper cover recess 101 and the lower cover recess 102, that is, the upper cover recess 101 is folded over 180°. At this time, the upper cover recess 101 and the lower cover recess 102 are closed. Moreover, the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 on one side of the upper cover recess 101 are respectively aligned with the first positioning hole 1061, the second positioning hole 1062, and the third positioning hole 1063 on one side of the lower cover recess 102. Therefore, the upper cover encapsulation skirt 103 and the lower cover encapsulation skirt 104 are in a mutually aligned position.

[0055] It should be noted that when the upper cover recess 101 is folded 180° over, and the upper cover recess 101 and the lower cover recess 102 are closed, the corresponding first positioning hole 1061 ensures that the upper cover recess 101 and the lower cover recess 102, as well as the upper cover packaging skirt and the lower cover packaging skirt, are aligned during packaging. It also serves as a positioning tool for subsequent processes, especially for resealing and trimming after formation. The second positioning hole 1062 mainly serves as an auxiliary positioning tool, ensuring that the aluminum-plastic shell does not experience significant displacement or sliding during packaging. The third positioning hole 1063 further secures the upper cover recess 101 and the lower cover recess 102, and further stabilizes the alignment of the upper cover recess 101 and the lower cover recess 102, as well as the upper cover packaging skirt and the lower cover packaging skirt, based on the first positioning hole 1061.

[0056] The sealed casing, along with the battery cell encapsulated within, is then secured to the encapsulation fixture, such as... Figure 3 and Figure 6 As shown, the positioning pin group 401, which is provided on the packaging and fixing fixture 40 corresponding to the positioning hole group 106, passes through the positioning hole group 106 and engages, so that the closed shell is fixed on the packaging and fixing fixture. The packaging and fixing fixture 40 is also provided with a cell support fixing platform 402, positive and negative electrode ear slots, and fixing slots 405, which fix the closed shell 10 together with the battery cell encapsulated therein on the packaging and fixing fixture 40. The cell support fixing platform 402 is used to install the closed shell 10 together with the battery cell encapsulated therein, the positive and negative electrode ear slots are used to install the positive and negative electrodes, and the fixing slots 405 are used to fix the packaging and fixing fixture 40 on the packaging mold head.

[0057] Specifically, such as Figure 6As shown, the encapsulation and fixing fixture 40 is provided with two sets of positioning pin groups 401, a cell support fixing platform 402, positive and negative electrode ear slots, and fixing slots 405. The positioning pin groups 401 and the positioning hole groups are in one-to-one correspondence. It can be understood that the positioning pin groups 401 are also arranged in a row of first positioning pins 4011, second positioning pins 4012, and third positioning pins 4013. That is, the positioning pin group 401 includes the first positioning pins 4011, second positioning pins 4012, and third positioning pins 4013. In other words, the distribution of the first positioning pins 4011, second positioning pins 4012, and third positioning pins 4013 is determined by the first positioning hole, second positioning hole, and third positioning hole. It can be understood that the distribution, structure, and size relationship of the first positioning pins 4011, second positioning pins 4012, and third positioning pins 4013 can be determined according to the position distribution, structure, and size relationship of the first positioning hole, second positioning hole, and third positioning hole.

[0058] like Figure 3 As shown, when the upper cover pit 101 and the lower cover pit 102 are closed, the corresponding positioning hole groups 106 of the upper cover pit 101 and the lower cover pit 102 will overlap, reducing the four positioning hole groups 106 to two. When the closed housing 10, together with the battery cell encapsulated therein, is fixed on the packaging fixture 40, the two sets of first positioning pins, second positioning pins, and third positioning pins pass through the corresponding two sets of first positioning holes 1061, second positioning holes 1062, and third positioning holes 1063, respectively, thus fixing the closed housing 10 on the packaging fixture and preventing displacement during packaging. Moreover, at this time, the closed housing, together with the battery cell encapsulated therein, is installed on the battery cell support fixing platform. That is, the battery cell support fixing platform mainly stabilizes the closed housing and the battery cell, and its specific structure and dimensions can be determined according to the specific working conditions.

[0059] like Figure 5 and Figure 6 As shown, the positive tab 20 and the negative tab 30 are installed in the corresponding positive tab slot 403 and negative tab slot 404. That is, the positive tab slot 403 and the negative tab slot 404 are determined according to the positive tab 20 and the negative tab 30. It can be understood that the distribution, size and structure of the positive tab 20 and the negative tab 30 determine the distribution, size and structure of the corresponding positive tab slot 403 and the negative tab slot 404.

[0060] After fixing the covered housing and the battery cell inside onto the packaging fixture, the packaging fixture with the covered housing is then fixed onto the packaging mold head, and the covered housing is packaged on the packaging mold head.

[0061] Specifically, such as Figure 6As shown, the encapsulation fixture 40, with the capped housing fixed on it, is fixed to the encapsulation mold head. The fixture is then secured to the encapsulation module via a corresponding snap-fit ​​structure on the encapsulation module using a fixing slot 405. This secures the encapsulation fixture 40 to the encapsulation mold head, and encapsulation is then performed on the mold head. Here, there are no restrictions on the encapsulation mold head or the snap-fit ​​structure that engages with the fixing slot 405, as long as they meet the operational requirements.

[0062] Next, we will explain in detail the encapsulation operation of the sealed shell on the mold head.

[0063] like Figure 3 and Figure 5 As shown, the encapsulation includes: first encapsulation 50: the side sealing area 503 and top sealing area 502 of the covered housing 10 are simultaneously encapsulated 50; second encapsulation 60: the liquid injection hole at a preset distance from the center of the housing 10 is encapsulated 60; re-encapsulation 70: the unencapsulated area in the top sealing area is re-encapsulated 70.

[0064] Specifically, after securing the folded button lithium-ion battery semi-finished product (the covered casing 10 and the battery cell) as described above, it needs to be packaged on the packaging mold. For example... Figure 3 and Figure 5 As shown, the first encapsulation is 50, which means that the side sealing area 503 and the arc-shaped top sealing area 502 are encapsulated simultaneously. In other words, the side sealing area 503 and the arc-shaped top sealing area 502 are encapsulated as a whole. This can avoid problems such as over-melting or poor melting in the contact area due to multiple encapsulations.

[0065] Specifically, the central angle corresponding to the arc-shaped top sealing area 502 is 330° to 300°, and the area corresponding to the first encapsulation covers its top. It can be understood that the top of the arc-shaped top sealing area 502 in the first encapsulation has already been encapsulated in the first encapsulation. The side sealing area 503 is specifically the area extending downward along both ends of the arc-shaped top sealing area.

[0066] During the initial encapsulation process (50 cycles), key parameters need to be set, such as: temperature, which is typically set within the range of 160℃ to 200℃ based on the characteristics of the inner layer material of the aluminum-plastic film; pressure, applying uniform linear pressure, typically within the range of 0.3MPa to 0.6MPa; and time, with the pressure-holding heating time usually between 3 and 8 seconds. The inner layer material of the aluminum-plastic film is cast polypropylene (CPP), providing heat-sealing sealing and resistance to electrolyte corrosion. Of course, the above key parameters are not exhaustive; they are merely illustrative examples. Key parameters can be set according to specific working conditions, and are not listed here in detail.

[0067] During the initial encapsulation process 50, heat is conducted through the sealing head to the aluminum-plastic film, causing the CPP material of the inner layers of the upper and lower aluminum-plastic films of the sealed shell to melt rapidly. Under pressure, the molten CPP flows, achieving not only fusion between CPP layers but also fusion and embedding between the CPP layers and the special polymer coatings on the surfaces of the positive and negative electrode tabs. This process forms three continuous fusion sealing edges with preliminary sealing strength in the top sealing area 502 and the side sealing areas 503 on both sides, and the positive and negative electrode tabs are firmly encapsulated and insulated within these sealing edges.

[0068] Moreover, such as Figures 3-4 As shown, during the first encapsulation 50, an arc shape 501 is formed at the junction of the encapsulation areas of the side sealing area 503 and the top sealing area 502. The central angle of the arc shape 501 is 20° to 60°. The arc shape 501 is used to reduce the area of ​​the overlapping region between the supplementary encapsulation 70 and the top sealing area 502 of the first encapsulation 50.

[0069] Specifically, an arc shape 501 is formed at the junction of the side sealing area 503 and the top sealing area 502. This arc shape 501 reduces the area of ​​overlap between the top sealing area 502 of the re-sealing 70 and the first sealing 50, thereby reducing the risk of defects caused by repeated sealing at the junction. Furthermore, the central angle corresponding to the arc shape 501 at the junction is 20° to 60°, including the endpoints (the numerical range in this application includes the endpoints), i.e., including 20° and 60°. More preferably, the central angle corresponding to the arc shape 501 is 30° to 45°. If the arc shape 501 is a straight line, there is no sealing buffer at the junction, and thermal radiation will cause obvious junction marks, affecting the sealing effect and appearance.

[0070] Before the second encapsulation, electrolyte is injected through the injection hole. The electrolyte enters the cell through the unencapsulated area in the top sealing region and undergoes formation and venting.

[0071] Specifically, after the first encapsulation is completed and before the second encapsulation is performed, electrolyte needs to be injected through the injection hole. The injection hole and the unencapsulated area in the top sealing area are connected. The electrolyte will enter the lower cover pit through the injection hole and the unencapsulated area in the top sealing area. After the electrolyte injection is completed, it is transferred to the standing rack and left to stand at room temperature or a certain temperature (such as 25-60°C) for a predetermined time (such as 24-72 hours). This process allows the electrolyte to naturally wet the diaphragm and electrode by capillary action.

[0072] Since the electrolyte and the process of injecting the electrolyte are existing technologies, we will not go into too much detail about the electrolyte and the process of injecting the electrolyte here. You can choose the appropriate electrolyte and the amount of electrolyte according to the specific working conditions.

[0073] After soaking, as Figure 3 and Figure 5 As shown, a second encapsulation 60 is then performed, at a preset distance from the liquid injection hole 107 at the center of the housing. This second encapsulation 60 is a pre-sealing to prevent electrolyte leakage or moisture intrusion during subsequent transportation. In this embodiment, the preset distance means that the distance between the second encapsulation 60 and the liquid injection hole 107 is less than 5mm. Of course, the specific value of the preset distance can also be determined according to the specific working conditions, and no excessive restrictions are imposed here.

[0074] After the second encapsulation process is completed, the cell needs to undergo formation, which involves the first charge-discharge activation of the cell. The core purpose is to form a stable solid electrolyte interface film on the negative electrode surface. During this process, gas will be generated inside the cell, causing the aluminum-plastic film gas bag to bulge, which is a normal phenomenon.

[0075] The formed battery cell is then transferred to the degassing station, where, within the sealed chamber of a vacuum degassing and sealing machine, the gas bag inside the cell is punctured using a special needle. The vacuum system is then activated to forcefully extract the gas from the cell (vacuum levels can reach -98 kPa or higher), for a duration ensuring complete gas removal (e.g., 10-20 seconds). Finally, under the protection of maintaining a vacuum or filling with an inert gas (e.g., nitrogen), as... Figure 3 and Figure 5 As shown, the unsealed area in the top sealing zone is resealed (70). Resealing (70) is the final and most critical sealing of the cell body. During this process, the heat sealing temperature, pressure, and time must be precisely controlled to ensure sealing strength and tightness. The specific values ​​for heat sealing temperature, pressure, and time can be determined based on the specific working conditions and will not be elaborated upon here.

[0076] It should be noted that, as Figure 3 and Figure 7 As shown, the package width of the re-sealment 70 is greater than the package width of the top seal area of ​​the first package 50, and the central angle corresponding to the area of ​​the re-sealment 70 is 30° to 60°.

[0077] Specifically, the arc-shaped package width of the re-sealing 70 is W1, which is 1 to 3 times the arc-shaped top sealing area width W of the first package 50, more preferably 1.5 to 2.5 times, and even more preferably 2 times. Increasing the package area of ​​the re-sealing 70 can improve the packaging efficiency and reduce the impact of residual electrolyte on the aluminum-plastic shell on the packaging.

[0078] The central angle of the area corresponding to the resealing 70 is 30° to 60°, more preferably 60°. Within this preferred unsealed radius, the electrolyte in the airbag 105 can be maximized to enter the mold cavity, accelerating electrolyte wetting. Furthermore, a central angle of 60° for the resealing 70 area avoids leakage caused by an excessively large unsealed area and prevents the unsealed area from shrinking due to heat radiation, thus affecting subsequent electrolyte flow. It also creates sufficient sealing space for the subsequent resealing of the unsealed area, ensuring even distribution of heat energy during resealing 70 and reducing the impact of residual electrolyte on the packaging.

[0079] After packaging is complete, such as Figure 5 and Figure 7 As shown, the casing is trimmed, removing the area where the width of the re-sealment 70 is greater than the top seal width of the first seal 50 to form a button lithium-ion battery. Specifically, the area of ​​the re-sealment 70 with a radius greater than W1 is simultaneously trimmed during the trimming process. The wider area of ​​the re-sealment 70 prevents residual electrolyte in the airbag 105 from leaking and contaminating the equipment and the cell surface during trimming. This can be understood as cutting away the emptied airbag along the outside of the re-sealment 70 to obtain a final cell with a smooth appearance. The cell is then visually inspected to ensure that the seal edges are free of wrinkles and electrolyte contamination.

[0080] The performance of the button lithium-ion battery obtained through the packaging process of this application is compared with that of the button lithium-ion battery obtained through conventional technology. The specific comparison is as follows: 1. The performance comparison of the packaged cells of the present application's technical solution and the traditional technical solution after 28 days of high temperature and high humidity storage is shown in Table 1: Table 1 As shown in Table 1 above, the battery cells packaged using the packaging process of this application exhibit lower rates of change in voltage, resistance, and thickness (at room temperature, high temperature, and low temperature) after 28 days compared to those packaged using conventional techniques. Furthermore, the battery cells packaged using the packaging process of this application demonstrate higher capacity retention and recovery rates after 28 days compared to those packaged using conventional techniques. Additionally, the battery cells packaged using the packaging process of this application show no change in appearance after 28 days, while battery cells packaged using conventional techniques exhibit bloating after 28 days.

[0081] 2. A comparison of the battery cell packaging process and performance between this technical solution and traditional technical solutions is shown in Table 2: Table 2 As can be seen from Table 2 above, the battery cells packaged using the packaging process of this application have lower rates of poor packaging, poor appearance (electrolyte contamination, misalignment of upper and lower covers, etc.), average internal resistance after capacity testing, and leakage of packaging electrolyte compared to the battery cells packaged using the traditional technology.

[0082] This application also provides a housing, such as Figure 2 As shown, the housing is used to install the battery cell in the packaging process of the button lithium-ion battery; the housing 10 includes: an upper cover pit 101, a lower cover pit 102, an upper cover packaging skirt 103, a lower cover packaging skirt 104, and an airbag 105. The upper cover pit 101 and the lower cover pit 102 are respectively arranged on opposite sides of the airbag 105. The battery cell is installed in the lower cover pit 102, and the positive and negative terminals are electrically connected to the battery cell; and four sets of positioning hole groups 106 are symmetrically arranged along the circumference of the airbag 105 and close to the upper cover pit 101 and the lower cover pit 102. The positioning hole groups 106 are a first positioning hole 1061, a second positioning hole 1062, and a third positioning hole 1063 arranged in an array.

[0083] The contents of the same parts of the casing will not be explained in detail here. Please refer to the above embodiment of the packaging process of button lithium-ion batteries.

[0084] This application also provides a sealing and fixing fixture, such as Figure 6 As shown, the packaging fixture 40 is used to fix the casing and the battery cell in the packaging process of a button lithium-ion battery. The packaging fixture 40 includes: a battery cell support and fixing platform 402, positive and negative electrode tab slots (positive electrode tab slot 403 and negative electrode tab slot 404), a fixing slot 405, and a positioning pin group 401. The battery cell support and fixing platform 402 is used to install the casing after it is closed, together with the battery cell enclosed therein. The positioning pin group 401 passes through the corresponding positioning hole group and engages. The positive and negative electrode tab slots are used to install the positive and negative electrode tabs to fix the casing after it is closed, together with the battery cell enclosed therein, on the packaging fixture. The fixing slot 405 is used to fix the packaging fixture with the casing after it is closed on the packaging mold head.

[0085] For the packaging fixture, the same embodiment can be referred to the embodiment of the packaging process of button lithium-ion batteries, and will not be described in detail here.

[0086] It should be noted that although several structures, components, or units for implementing the relevant functions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to the specific embodiments of this application, the features and functions of two or more structures, components, or units described above can be embodied in one structure, component, or unit. Conversely, the features and functions of one structure, component, or unit described above can be further divided and embodied by multiple components, structures, or units.

[0087] Furthermore, although the various components of the components or apparatus in this application and the mounting arrangements between them are described in a specific order in the accompanying drawings, this does not require or imply that the components or apparatus must be designed according to that specific component or mounting arrangement, or that all the components shown must be included to achieve the desired result. Additional or alternative components may be omitted, multiple components may be combined into one component to achieve the corresponding function, and / or a component may be decomposed into multiple components to achieve the corresponding function, etc.

[0088] Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A packaging process for a button lithium-ion battery, characterized in that, include: Stamped housing: The stamped housing includes: an upper cover recess, a lower cover recess, an upper cover sealing skirt, a lower cover sealing skirt, and an airbag. The upper cover recess and the lower cover recess are located on opposite sides of the airbag, and four sets of positioning holes are symmetrically stamped along the circumference of the airbag and close to the upper cover recess and the lower cover recess. The positioning hole sets are a first positioning hole, a second positioning hole, and a third positioning hole arranged in an array. Install the battery cell: Install the battery cell in the lower cover pit and electrically connect the positive and negative tabs to the battery cell; Closing: The housing is folded along the axis of symmetry of the upper cover pit and the lower cover pit. After folding, the upper cover pit and the lower cover pit are closed, and the positioning hole group on one side of the upper cover pit and the positioning hole group on one side of the lower cover pit are aligned with each other, so that the upper cover encapsulation skirt and the lower cover encapsulation skirt are in a mutually aligned position. Upper fixture fixation: The covered housing together with the battery cell encapsulated therein is fixed on the packaging fixture, wherein the covered housing is fixed on the packaging fixture by the positioning pin group corresponding to the positioning hole group through the positioning hole group. Encapsulation: The encapsulation fixture, which has the covered housing, is fixed on the encapsulation mold head, and the covered housing is encapsulated on the encapsulation mold head.

2. The packaging process for a button lithium-ion battery according to claim 1, characterized in that, The diameter of the first positioning hole is equal to the diameter of the second positioning hole, and the diameter of the third positioning hole is smaller than the diameters of the first positioning hole and the second positioning hole.

3. The packaging process for the button lithium-ion battery according to claim 1, characterized in that, The package includes: First sealing: The side sealing area and top sealing area of ​​the closed shell are simultaneously sealed for the first time; Second sealing: A second sealing is performed at a predetermined distance from the liquid injection hole at the center of the housing; Resealing: Resealing the unsealed area in the top sealing area.

4. The packaging process for a button lithium-ion battery according to claim 3, characterized in that, During the first encapsulation, an arc shape is formed at the junction of the encapsulation areas of the side sealing area and the top sealing area. The central angle of the arc shape is 20° to 60°. The arc shape is used to reduce the area of ​​the overlapping region between the re-sealing and the top sealing area of ​​the first encapsulation.

5. The packaging process for a button lithium-ion battery according to claim 3, characterized in that, Before the second encapsulation, electrolyte is injected through the injection hole. The electrolyte enters the cell through the unencapsulated area in the top sealing region and undergoes formation and venting.

6. The packaging process for a button lithium-ion battery according to claim 3, characterized in that, The width of the resealed area is greater than the width of the top sealing area of ​​the first package, and the central angle of the resealed area is 30° to 60°.

7. The packaging process for a button lithium-ion battery according to claim 6, characterized in that, After encapsulation, the shell is trimmed to remove the area where the width of the re-sealed encapsulation is greater than the width of the top sealing area of ​​the first encapsulation, in order to form a button lithium-ion battery.

8. The packaging process for a button lithium-ion battery according to claim 1, characterized in that, The packaging fixture is further provided with a cell support and fixing platform, positive and negative electrode tab slots, and a fixing slot to fix the closed housing together with the cell enclosed therein onto the packaging fixture. The cell support and fixing platform is used to install the closed housing together with the cell enclosed therein, the positive and negative electrode tab slots are used to install the positive and negative electrodes, and the fixing slot is used to fix the packaging fixture onto the packaging mold head.

9. A housing, characterized in that, The housing is used to mount the battery cell in the packaging process of a button lithium-ion battery. The housing includes: an upper cover pit, a lower cover pit, an upper cover sealing skirt, a lower cover sealing skirt, and an airbag. The upper cover pit and the lower cover pit are respectively located on opposite sides of the airbag. The battery cell is installed in the lower cover pit, and the positive and negative terminals are electrically connected to the battery cell. Four sets of positioning holes are symmetrically arranged along the circumference of the airbag and close to the upper cover pit and the lower cover pit, respectively. The positioning hole sets are a first positioning hole, a second positioning hole, and a third positioning hole arranged in an array.

10. A packaging and fixing fixture, characterized in that, The packaging fixture is used to fix the casing and the cell in the packaging process of button lithium-ion batteries. The packaging and fixing fixture includes: a cell support and fixing platform, positive and negative electrode ear slots, a fixing slot, and a positioning pin group; the cell support and fixing platform is used to install the covered housing together with the cell enclosed therein, the positioning pin group passes through the corresponding positioning hole group and engages, the positive and negative electrode ear slots are used to install the positive and negative electrodes to fix the covered housing together with the cell enclosed therein on the packaging and fixing fixture, and the fixing slot is used to fix the packaging and fixing fixture with the covered housing fixed on the packaging mold head.

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