Hollow sleeve, method of manufacture, electrode assembly and mass traceability system

Abstract

The present application relates to a kind of hollow sleeve, preparation method, electrode assembly and quality traceability system, the sleeve includes cylinder, and the one end of cylinder is formed with flange of turn-up;Guiding groove is arranged on the inner wall of cylinder, and guiding groove is arranged around the axis of cylinder.The present application also discloses a kind of sleeve preparation method, electrode assembly and quality traceability system.The present application is conducive to improving the sealing reliability of electrode assembly.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a hollow sleeve, a preparation method, an electrode assembly, and a quality traceability system. Background Technology

[0002] The electrode assembly in the battery is located on the casing to electrically connect the internal battery cell and external electrical components through the electrode assembly. Electrode assemblies are typically fixed to the housing using a riveting process, but this method is difficult to guarantee in terms of yield and production efficiency. Furthermore, these electrode assemblies generally include terminals, and an insulating component is required between the terminal and the housing to ensure insulation and sealing. Plastic sheets are commonly used as these insulating components, but plastics have low temperature resistance and poor corrosion resistance, making them prone to failure under thermal disturbance, humidity, or long-term mechanical stress, thus affecting the sealing and insulation performance of the battery housing and failing to meet the safety requirements of batteries under high-power charging and discharging conditions and long-term safety needs. To improve these issues, glass can be used instead of plastic sheets for glass sealing of the terminals. For example, the terminal can be placed in a cylindrical sleeve and sealed with glass. However, during the sealing process with the glass or subsequent thermal cycling tests, the interface between the sleeve and the glass is prone to microcracks due to stress concentration and restricted glass flow, resulting in poor sealing airtightness and even sealing failure. This reduces the reliability and yield of the sealing structure. Therefore, an improved sleeve structure is needed to address these problems. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to improve the sealing reliability of electrode components.

[0004] To solve the above-mentioned technical problems, the present invention provides a hollow sleeve, the sleeve including a cylindrical body, one end of which is formed with a flange; a guide groove is provided on the inner wall of the cylindrical body, the guide groove being arranged around the axis of the cylindrical body.

[0005] In one embodiment of the invention, the guide groove is a continuous annular groove.

[0006] In one embodiment of the present invention, a plurality of guide grooves are provided on the inner wall of the cylinder, and the plurality of guide grooves are evenly distributed circumferentially around the axis of the cylinder.

[0007] In one embodiment of the present invention, the depth of the guide groove is 0.02 to 0.08 mm.

[0008] In one embodiment of the present invention, the width of the guide groove is 0.05 to 0.2 mm.

[0009] In one embodiment of the present invention, the cylinder and the flange are connected by an arc-shaped fillet with a radius of 0.02 to 0.1 mm.

[0010] In one embodiment of the invention, the inner wall of the cylinder is provided with a linear stress buffer zone near the end of the flange.

[0011] In one embodiment of the present invention, the linear stress buffer is corrugated, and the amplitude of the corrugated linear stress buffer is 0.02 to 0.06 mm, and the wave pitch is 0.1 to 0.3 mm.

[0012] In one embodiment of the present invention, the linear stress buffer zone is a thinning strip, and the thinning depth of the thinning strip is 0.1 to 0.4 times the thickness of the cylinder.

[0013] In one embodiment of the present invention, the flange has a first surface and a second surface disposed opposite to each other, the first surface is provided with a first groove, the distance between the first surface and the second surface is a first thickness, and the depth of the first groove is 0.2 to 0.4 times the first thickness.

[0014] In one embodiment of the present invention, the first thickness is 0.12 to 0.18 mm.

[0015] In one embodiment of the present invention, the inner diameter of the cylinder is 0.5 to 2.25 mm.

[0016] In one embodiment of the invention, the cylinder and the flange are integrally formed.

[0017] This invention also discloses a method for preparing a hollow sleeve, comprising the following steps:

[0018] The sleeve is prepared by stretch forming process, so that the sleeve body and the flange are integrally formed.

[0019] A guide groove is machined on the inner wall of the cylinder;

[0020] The sleeve with the guide groove is annealed.

[0021] The present invention also discloses an electrode assembly comprising a sleeve, an electrode post, and a glass ring as described in any of the preceding claims, wherein the electrode post is located inside the sleeve; the sleeve and the electrode post are sealed together by the glass ring.

[0022] In one embodiment of the present invention, in the above-mentioned quality traceability system, a unique product code is set on the flange. The quality traceability system is used to collect the product code and retrieve the production data corresponding to the product code from the production database to achieve traceability management.

[0023] The technical solution of the present invention has the following advantages over the prior art:

[0024] The hollow sleeve and electrode assembly described in this invention, through the design of the guide groove, can better control the flow and discharge of gas during the hot-melt sealing of the electrode assembly, thereby reducing defects such as microcracks and decreased sealing airtightness caused by the generation of bubbles and uneven flow during the melting stage, and thus improving the sealing reliability of the electrode assembly. Attached Figure Description

[0025] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] Figure 1 This is a schematic diagram of the sleeve structure in this invention;

[0027] Figure 2 This is a schematic diagram of the electrode assembly of the present invention;

[0028] Figure 3 yes Figure 2 Another structural schematic diagram of the middle electrode assembly;

[0029] Figure 4 yes Figure 2 Top view of the middle electrode assembly;

[0030] Figure 5 yes Figure 4 Sectional view at point AA;

[0031] Figure 6 yes Figure 5 A magnified view of a section at point M;

[0032] Figure 7 yes Figure 5 Schematic diagram of the middle sleeve;

[0033] Figure 8 This is a schematic diagram of one state during the heat fusion sealing of the electrode assembly;

[0034] Figure 9 This is a flowchart of the electrode assembly heat-sealing process;

[0035] Figure 10 This is a schematic diagram of the welding between the electrode assembly and the housing;

[0036] Figure 11 yes Figure 10 A bottom view of the structure shown;

[0037] Figure 12 This is a schematic diagram of the stretching die in this invention;

[0038] Figure 13 This is a schematic diagram of the blanking die in this invention;

[0039] Figure 14 This is a schematic diagram of the structure of the flanging extrusion die in this invention;

[0040] Figure 15 This is a schematic diagram of the internal cavity shaping mold in this invention;

[0041] Figure 16 This is a schematic diagram (top view) showing the arrangement of the expansion die heads in the internal cavity shaping mold.

[0042] Figure 17 yes Figure 15 A magnified view of a section at point G1;

[0043] Figure 18 This is a schematic diagram of the end face shaping mold in this invention;

[0044] Figure 19 yes Figure 18 A magnified view of a section at point G2;

[0045] Explanation of reference numerals in the instruction manual:

[0046] 10. Electrode assembly; 101. Electrode post; 102. Glass ring; 103. Sleeve; 1031. Cylinder body; 10311. Guide groove; 1032. Flanged flange; 10321. First surface; 10322. Second surface; 1033. Rounded corner;

[0047] 20. Housing; 2011. Mounting hole; 2023. Circumferential weld mark;

[0048] 50. Drawing die; 501. Third cavity; 5011. Third lower cavity; 502. Third pressure block; 5021. Third upper cavity; 503. Drawing punch;

[0049] 60. Blanking die; 601. Fourth die cavity; 6011. Fourth lower cavity; 602. Fourth blanking block; 6021. Fourth upper cavity; 603. Blanking punch;

[0050] 70. Flanging and extrusion die; 701. Fifth cavity die; 7011. Fifth lower cavity; 702. Fifth pressure block; 7021. Fifth upper cavity; 703. Extrusion punch;

[0051] 80. Inner cavity shaping mold; 801. First cavity die; 8011. First lower cavity; 802. First pressure block; 8021. First upper cavity; 80211. Tapered hole; 803. Expanding die head; 8031. Wedge-shaped die core; 80311. Wedge end; 8032. Die flap; 8033. First receiving cavity; 8034. Gap;

[0052] 90. End face shaping mold; 901. Second cavity; 9011. Second lower cavity; 902. Second pressure block; 9021. Second upper cavity; 903. Upsetting punch; 9031. Arc end; 904. Inner bushing; Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present disclosure or its application or use.

[0054] In the description of this invention, it should be understood that the terms "vertical," "upper," "lower," "top," "side," "inner," and "outer," 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 the invention 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 the invention. 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] Example 1

[0057] See Figure 1 , Figure 6 and Figure 7This embodiment discloses a hollow sleeve 103, which includes a cylindrical body 1031, one end of which is formed with a flanged flange 1032; a guide groove 10311 is provided on the inner wall of the cylindrical body 1031, and the guide groove 10311 is arranged around the axis of the cylindrical body 1031. For example, the guide groove 10311 is provided on the inner wall of the cylindrical body 1031, and the axis of the cylindrical body 1031 is perpendicular to the guide groove 10311. Each guide groove 10311 is equidistant from the top surface of the sleeve 103. It can be understood that... Figure 7 As shown, the axis of the cylinder 1031 is O1-O1, and the guide groove 10311 is a symmetrical figure with a symmetrical plane of O2-O2. That is, the guide grooves 10311 are all vertically symmetrical with respect to their symmetrical planes O2-O2. Therefore, the axis of the cylinder 1031, O1-O1, is perpendicular to the symmetrical plane of the guide groove 10311, O2-O2, and the symmetrical plane of the guide groove 10311 is equidistant from the top surface of the sleeve 103.

[0058] Furthermore, the guide groove 10311 is optimally positioned such that the distance between the guide groove 10311 and the top surface of the sleeve 103 is 40%-60% of the sleeve height, that is... Figure 7 The distance between the symmetrical plane O2-O2 and the top surface of the sleeve 103 is 40%-60% of the sleeve height. This method ensures that the guide groove is basically located in the middle region of the sleeve. Since the top and bottom ends of the sleeve are open, if the guide groove area is closer to the top or bottom end, it will be more likely to cause sleeve deformation. In addition, the middle region of the sleeve is also the thicker middle region of the subsequent molten glass. The guide groove set in this middle region will eventually be filled by the glass, which helps to improve the reliability of the connection between the sleeve and the glass.

[0059] The guide groove 10311 mentioned above is preferably set in a single circle. If multiple guide grooves are set at different heights of the sleeve, it is easy to cause deformation of the sleeve and the strength of the sleeve cannot be guaranteed. Especially when the sleeve itself has a thin wall thickness and a small overall size, the above problems caused by multiple circles will be more obvious.

[0060] The aforementioned sleeve 103 is used in the electrode assembly 10, which includes the sleeve 103, the electrode post 101, and the glass ring 102. The electrode post 101 is located inside the sleeve 103. The sleeve 103 and the electrode post 101 are heat-sealed together by the glass ring 102. Through the design of the aforementioned guide groove 10311, the glass flow can be guided during the glass melting or flow stage, and a gas escape path can be provided. This achieves control and buffering of the gas escape and the local flow direction of the glass, thereby reducing defects caused by the generation of bubbles and uneven flow during the melting stage (such as microcracks at the interface between the sleeve 103 and the glass, and reduced sealing airtightness). This improves the sealing reliability of the electrode assembly 10.

[0061] like Figure 8 As shown, during the heat-sealing process of the electrode assembly 10, the glass material between the sleeve 103 and the electrode post 101 melts and flows, contacting the sleeve 103 and the electrode post 101. As the glass fluid flows downwards, air is expelled by compression. Simultaneously, the guide groove 10311 on the inner wall of the cylinder 1031 better controls the flow of gas during the melting process and facilitates gas expulsion. Ultimately, both the electrode post 101 and the sleeve 103 are in full contact with the glass, thus sealing the electrode post 101 and the sleeve 103 together. Figure 8 The direction of the middle arrow indicates the direction of air discharge.

[0062] The aforementioned sleeve 103 is a metal part. For example, the sleeve 103 can be made of stainless steel, preferably 316L stainless steel.

[0063] In some embodiments, the guide groove 10311 is a continuous annular groove, that is, only one annular guide groove 10311 may be provided; for example, the width of the annular groove is 0.1 mm and the depth is 0.04 mm.

[0064] Or, such as Figure 7 As shown, a plurality of guide grooves 10311 are provided on the inner wall of the cylinder 1031. The plurality of guide grooves 10311 are evenly distributed around the axis of the cylinder 1031 in a circumferential manner to form a ring. That is, a plurality of guide grooves 10311 can be provided in a separated manner to better ensure the structural rigidity. For example, eight guide grooves 10311 in a separated manner can be provided on the inner wall of the cylinder 1031.

[0065] In some embodiments, the depth of the guide groove 10311 is 0.02–0.08 mm, specifically 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, etc. Excessive depth can cause localized stress concentration, affecting the sealing quality; insufficient depth makes it impossible to effectively control gas escape and the local flow direction of the glass during the hot-melt sealing process.

[0066] Furthermore, such as Figure 7 As shown, the width h of the guide groove 10311 is 0.05 to 0.2 mm. If the width is too large, it will reduce the strength of the sleeve; if it is too small, it will be impossible to effectively control the gas escape and the local flow direction of the glass during the hot melt sealing process.

[0067] The sleeve structure described above can reduce stress concentration at the glass-metal (cylinder) interface and control the glass flow and gas escape path, thereby significantly reducing the risk of interface cracks and seal leakage during subsequent glass sealing and thermal cycling.

[0068] In some embodiments, the cylinder 1031 and the flange 1032 are connected by a rounded fillet 1033 with a radius of 0.02–0.1 mm to eliminate stress concentration at sharp angles and better control the initial wetting surface of the glass during heating. It is understood that "wetting" refers to the phenomenon where molten liquid material (such as glass) spreads and covers the surface of the sealed component (such as the pole post 101, sleeve 103, etc.) during sealing.

[0069] For example, the radius of the arc fillet 1033 can be 0.03mm, 0.05mm or 0.07mm, etc.

[0070] To reduce shear stress caused by thermal expansion differences during the use of electrode assemblies or thermal cycling, a linear stress buffer zone can be provided on the inner wall of the cylinder 1031 near the flange 1032 to absorb stress through local deformation or elasticity when shear action occurs due to thermal expansion differences. Figure 7 As shown, this linear stress buffer can be set at... Figure 7 The inner wall area selected by the prescription box in the middle. The specific setting of the linear stress buffer is not shown in the figure.

[0071] A weakly coupled interface is achieved by using a linear stress buffer, which reduces the shear stress concentration caused by thermal expansion difference, lowers the glass interface crack rate, and improves the airtightness and thermal cycling reliability after sealing.

[0072] Furthermore, the linear stress buffer zone can be a thinning strip, the thinning depth of which is 0.1 to 0.4 times the thickness of the cylinder 1031. For example, a thinning strip can be formed by circumferential thinning treatment on the inner wall of the cylinder 1031 near the flange 1032. The wall thickness of the thinning strip is less than the wall thickness of the cylinder 1031. If the wall thickness of the cylinder 1031 is 0.15 mm, then the wall thickness of the thinning strip can be 0.11 mm, which is equivalent to a thinning (thinning depth) of approximately 27%.

[0073] Alternatively, the linear stress buffer can be corrugated, with an amplitude of 0.02–0.06 mm and a pitch of 0.1–0.3 mm.

[0074] In some configurations, the linear stress buffer is located above the rounded corner 1033. Further, in the height direction (i.e., the vertical direction), the linear stress buffer is located between the guide groove 10311 and the rounded corner 1033.

[0075] For example, in a specific implementation, an annular guide groove 10311 and a linear stress buffer in the form of a thin strip can be provided on the sleeve 103;

[0076] Alternatively, multiple guide grooves 10311 arranged circumferentially and a corrugated linear stress buffer can be provided on the sleeve 103. This method can ensure flow guidance while retaining more rigidity, and is suitable for sleeve applications with higher draw ratios.

[0077] In some implementations, such as Figure 7 As shown, the flange 1032 has a first surface 10321 and a second surface 10322 disposed opposite to each other. The first surface 10321 is provided with a first groove (not shown in the figure). The distance between the first surface 10321 and the second surface 10322 is a first thickness H3. The depth of the first groove is 0.2 to 0.4 times the first thickness H3.

[0078] The design of the first groove allows for localized controlled melting / heat transfer during subsequent welding of the electrode assembly and housing. This limits heat transfer during welding to the glass sealing area, preventing glass annealing failure or cracking, which in turn affects the sealing reliability of the electrode assembly. Furthermore, the design of the first groove facilitates assembly positioning, improving the efficiency of industrialized automated assembly.

[0079] The first groove mentioned above can be obtained by surface thinning or by creating microgrooves. For example, the length of the microgroove is 0.5 to 1 mm and the depth is 0.02 to 0.05 mm.

[0080] In some embodiments, the thickness of the flange 1032—the first thickness H3—is 0.12 to 0.18 mm.

[0081] The thickness L1 of the cylinder 1031 is the same as the thickness of the flange 1032, which is 0.12 to 0.18 mm, specifically 0.15 mm, 0.16 mm, etc. The overall sleeve 103 is a thin-walled structure.

[0082] In some implementations, such as Figure 5 As shown, the inner diameter D3 of the cylinder 1031 is 0.5–2.25 mm. Further, the inner diameter D3 of the cylinder 1031 is 1.2–2.1 mm, for example, it can be 1.8 mm. This inner diameter of the cylinder 1031 is on the order of minute inner diameters.

[0083] The height H1 of the sleeve 103 is no greater than 0.5mm. Further, the height of the sleeve 103 can be 0.45 to 0.5mm, specifically 0.475mm.

[0084] In some implementations, the outer diameter D1 of the final flange 1032 is 2 to 3 mm, for example, it can be 2.2 mm, 2.5 mm, 2.6 mm, 2.8 mm, etc.

[0085] The guide groove design in this embodiment is particularly suitable for sleeve structures with small inner diameters and thin walls. Through the above design, the shear stress between glass and metal during thermal cycling can be effectively relieved, crack formation can be reduced, and the manufacturing yield of small sealing structures can be improved.

[0086] The electrode assembly and the battery casing can be fixed by welding. The flange 1032 in the sleeve 103 has the following functions during the welding process: First, it serves as a thermal buffer zone for the weld, effectively dispersing welding stress and preventing heat input during the welding process from being transferred to the glass sealing area, causing glass annealing failure or cracking, and also helping to reduce welding deformation; Second, it improves the alignment and positioning accuracy of the weld, avoiding welding offset caused by the deformation of thin material; Third, it enhances the mechanical bonding strength between the weld and the edge of the battery casing, thereby improving the sealing performance and reliability of the overall structure.

[0087] In addition, when the sleeve 103 and the pole post 101 are sealed together using the glass ring 102, the sleeve structure with the flange 1032 is more conducive to reducing stress concentration and improving the reliability of the connection between the sleeve 103 and the glass ring 102. Furthermore, the flange 1032 can be clamped and positioned during the sealing process to achieve the positioning of the sleeve, which is conducive to improving the convenience and accuracy of assembly, as well as improving assembly efficiency.

[0088] In some embodiments, the cylinder 1031 and the flange 1032 are integrally formed without welding or splicing, which helps to improve the mechanical strength, mechanical stability and processing consistency of the sleeve structure, reduces stress concentration, improves the stability of the joint interface when the sleeve and the glass are combined, and has higher reliability, thereby better ensuring the airtightness of the seal and the reliability of use.

[0089] This embodiment also discloses a method for preparing a hollow sleeve 103, including the following steps:

[0090] S1, see reference Figures 12-19 The sleeve 103 is prepared by stretch forming process, so that the sleeve body 1031 and the flange 1032 are integrally formed.

[0091] S2. A guide groove 10311 is machined on the inner wall of the cylinder 1031;

[0092] Specifically, the stretched sleeve 103 can be placed in a micro-machining device and processed by one or more of the following methods: laser micro-engraving, mechanical rolling or chemical etching, to obtain the guide groove 10311.

[0093] S3. Anneal the sleeve 103 with guide groove 10311 to release work hardening stress and restore the material structure, so that its structural dimensions can be stabilized.

[0094] The annealing temperature is 900–1100°C; further, the annealing temperature is 950–1050°C, specifically 980°C, 990°C, 1000°C, 1030°C, etc. During annealing, short-time annealing and controlled cooling rate can be used to avoid excessively rapid cooling and the generation of new stress.

[0095] In some methods, during the fabrication of the sleeve 103, after obtaining the guide groove 10311 in step S2, a linear stress buffer zone is also prepared on the inner wall of the cylinder 1031 near the flange 1032. This buffer zone can be directly formed in a mold through rolling or mold cavity texturing. An arc-shaped fillet 1033 is formed between the cylinder 1031 and the flange 1032. For example, micro-rolling or mold chamfering can be used to form an arc-shaped fillet 1033 with R≈0.05 mm at the transition between the cylinder 1031 and the flange 1032. Then, step S3 is performed.

[0096] After annealing the sleeve 103 with guide groove 10311 in step S3, the surface of the flange 1032 is also finished by grinding or plasma cleaning to ensure that the surface is clean and flat and meets the subsequent positioning and fitting requirements.

[0097] The flange 1032 has a first surface 10321 and a second surface 10322 that are disposed opposite to each other. After the flange 1032 is surface finished, a first groove can be provided on the first surface 10321 as a controllable weak point. The first groove can be obtained by laser thinning or other means to be used for localized controlled melting / heat transfer during subsequent welding to limit the heat transferred to the glass ring 102 region.

[0098] After the sleeve 103 is prepared, it is necessary to perform appearance and dimensional inspection (inner diameter, outer diameter, height, tolerance); surface defect inspection such as no cracks, wrinkles and serious scratches; and batch airtightness benchmark test (no load) and microstructure inspection.

[0099] In some implementations, see Figures 12-19 The method for preparing the sleeve 103 by stretch forming in step S1 includes:

[0100] Step 1, refer to Figure 12 The sheet material is stamped and stretched to form a recessed part a2 in the middle of the sheet material, and a folded edge a1 is formed on the outer periphery of the top of the recessed part a2.

[0101] Step 2, refer to Figure 13The recessed portion a2 is punched to form the first through hole a3, that is, part of the bottom surface of the recessed portion a2 is punched away to allow it to pass through.

[0102] Step 3, refer to Figure 14 The inner wall of the recessed portion a2 is squeezed, causing the recessed portion a2 to deform and present a vertical cylindrical structure a4, thereby expanding the diameter of the first through hole a3; this process can straighten the side wall of the recessed portion a2 by squeezing the inner wall of the recessed portion a2.

[0103] Step 4, refer to Figure 15 The inner cavity of the vertical cylindrical structure a4 is shaped to make its inner cavity surface regular, thereby obtaining a vertical cylindrical structure a4 with a uniform inner diameter and a folded edge a1 of a set size; that is, the size and shape of the inner cavity can be further adjusted through the above inner cavity shaping to make it close to the size and shape required by the finished product.

[0104] Step 5, refer to Figure 18 The lower end face of the shaped vertical cylindrical structure a4 is flushed to make it flat. Understandably, before the flushing process, the lower end face of the vertical cylindrical structure a4 may be uneven. After the flushing process, the lower end face is flat, ensuring that the end faces are flush.

[0105] Step 6: After the alignment process, the vertical cylindrical structure a4 forms the cylinder 1031, the folded edge a1 forms the flange 1032, and the integrated structure formed by the cylinder 1031 and the flange 1032 forms the sleeve 103.

[0106] In some embodiments, when the sheet material is stamped and stretched in step 1 to form a recessed portion a2 in the center of the sheet material, the above-mentioned stretching forming process further includes: pre-stretching the sheet material to form a recessed portion in the center of the sheet material to form a pre-stretched part, and then stretching the pre-stretched part again to increase the depth of the recessed portion to a preset depth. That is, the above method adopts a segmented stretching forming method to better ensure the stretching quality.

[0107] For example:

[0108] Pre-stretching stage: The sheet material is pre-stretched to form a recessed portion a2 in the center. The sheet material can be a circular sheet with a diameter of 6.5 mm. During pre-stretching, the wall thickness of the pre-stretched part can be controlled at 0.15 ± 0.02 mm, and the height is approximately 0.20 mm. Lubricant (containing a trace amount of PTFE-based lubricant) can be added to the cavity of the pre-stretching die to prevent wrinkles from forming in the stretched part during stretching.

[0109] Re-stretching stage: In the re-stretching die, the pre-stretched part is further drawn to a depth close to the final height (e.g., 0.40 mm). During this stage, the stretching ratio and the stroke of the blank holder need to be controlled to avoid stretching defects.

[0110] The above-mentioned sheet material is austenitic stainless steel sheet, specifically 316L stainless steel sheet, for example, a 0.15mm cold-rolled sheet.

[0111] In some embodiments, when the sheet material is stamped and stretched in step 1 to form a recess a2 in the middle of the sheet material, a stretching die 50 is used, see [reference]. Figure 12 The above-mentioned stretching die 50 includes a third die 501 and a third pressure block 502 arranged sequentially from bottom to top. The third die 501 has a third lower cavity 5011, and the third pressure block 502 has a third upper cavity 5021. The third upper cavity 5021 is used to accommodate the stretching punch 503.

[0112] When performing stamping and stretching using the stretching die 50, the sheet material is placed between the third pressure block 502 and the third die 501 and pressed tightly. Then, the stretching punch 503 is driven to move downward and press against the sheet material, so that a recessed portion a2 is formed in the middle of the sheet material, and the portion pressed between the third pressure block 502 and the third die 501 forms a folded edge a1.

[0113] The stretching die 50 described above can be used in both the pre-stretching and re-stretching stages.

[0114] In some embodiments, the recess a2 is punched in step 2 so that the recess a2 forms the first through hole a3, and a punching die 60 can be used. (See reference) Figure 13 The above-mentioned blanking die 60 includes a fourth die cavity 601 and a fourth pressure block 602 arranged sequentially from bottom to top. The fourth die cavity 601 has a fourth lower cavity 6011, and the fourth pressure block 602 has a fourth upper cavity 6021. The fourth upper cavity 6021 is used to accommodate the blanking punch 603.

[0115] When punching using the above-mentioned punching die 60, the folded edge a1 is placed between the fourth pressure block 602 and the fourth die 601 and pressed tightly. Then, the punching punch 603 is driven to move downward to remove part of the bottom surface of the recessed portion a2 to form the first through hole a3.

[0116] In some embodiments, when the inner wall of the recess a2 is squeezed in step 3 to deform the recess a2 into a vertical cylindrical structure a4, a flanged extrusion die 70 is used. (See reference...) Figure 14The above-mentioned flanging extrusion die 70 includes a fifth concave die 701 and a fifth pressure block 702 arranged sequentially from bottom to top. The fifth concave die 701 has a fifth lower cavity 7011, and the fifth pressure block 702 has a fifth upper cavity 7021. The fifth upper cavity 7021 is used to accommodate the extrusion punch 703.

[0117] When extruding using the above-mentioned flanging extrusion die 70, the folded edge a1 is placed between the fifth pressure block 702 and the fifth die 701 and pressed tightly. Then, the extrusion punch 703 is driven to move downward to extrude the inner wall of the recess a2, so that the inner wall of the recess a2 gradually fits into the cavity wall of the fifth lower cavity 7011 and becomes flat, thereby forming a vertical cylindrical structure a4 in the recess a2.

[0118] In some embodiments, an inner cavity shaping mold 80 is used when shaping the inner cavity of the vertical cylindrical structure a4, see reference. Figure 15 The inner cavity shaping mold 80 includes a first concave mold 801 and a first pressure block 802 arranged sequentially from bottom to top. The first concave mold 801 has a first lower cavity 8011, and the first pressure block 802 has a first upper cavity 8021. The first upper cavity 8021 is used to accommodate an expansion mold head 803. The expansion mold head 803 includes a plurality of circumferentially distributed mold petals 8032. All mold petals 8032 can close together or expand outward.

[0119] When shaping the inner cavity of the vertical cylindrical structure a4 using the aforementioned inner cavity shaping mold 80, the following steps are included:

[0120] The folded edge a1 is placed between the first pressure block 802 and the first die 801 and pressed tightly, so that the vertical cylindrical structure a4 is placed in the first lower cavity 8011. Then, the bottom end of the expansion die head 803 extends into the inner cavity of the vertical cylindrical structure a4 and drives the die flap 8032 to expand outward and press against the inner wall of the vertical cylindrical structure a4 to achieve inner cavity shaping, making the shape of the inner cavity more regular and the inner diameter also reaches the set inner diameter.

[0121] Further, see Figures 15-16 The expansion mold head 803 includes multiple mold lobes 8032, all of which form a first accommodating cavity 8033. The first accommodating cavity 8033 contains a wedge-shaped mold core 8031. The lower part of the wedge-shaped mold core 8031 ​​has a wedge-shaped end 80311 with an inclined wedge-shaped surface. The shape of the lower part of the first accommodating cavity 8033 is adapted to the shape of the wedge-shaped end 80311 and is also wedge-shaped. When the wedge-shaped mold core 8031 ​​is pushed downward, the outer mold lobes 8032 of the wedge-shaped mold move outward.

[0122] In some embodiments, a gap 8034 is provided between the upper part of the wedge-shaped mold core 8031 ​​and the first accommodating cavity 8033 to facilitate the up-and-down movement of the mold core and reduce motion resistance.

[0123] Furthermore, such as Figure 16 As shown, all the lobes 8032 that form the first accommodating cavity 8033 are evenly distributed circumferentially to improve motion stability and force balance.

[0124] In some specific ways, such as Figure 16 As shown, the horizontal cross-section of the 8032 module is fan-shaped.

[0125] In some specific ways, such as Figure 15 As shown, a tapered hole 80211 is provided at the bottom of the first upper cavity 8021. The tapered hole is larger at the top and smaller at the bottom, so as to facilitate the mold piece 8032 to enter the first upper cavity.

[0126] Specifically, when the above-mentioned inner cavity shaping mold 80 shapes the inner cavity of the vertical cylindrical structure a4: the vertical cylindrical structure a4 is placed in the first lower cavity 8011, the folded edge a1 is placed between the first pressure block 802 and the first concave mold 801 and pressed tightly, then the expansion mold head 803 is placed in the first upper cavity 8021 and the bottom end of the expansion mold head 803 extends into the inner cavity of the vertical cylindrical structure a4, and the wedge mold core 8031 ​​is pushed, so that the outer mold petals 8032 of the wedge mold moves outward and presses against the inner wall of the vertical cylindrical structure a4 to achieve inner cavity shaping.

[0127] For example, after the inner cavity of the vertical cylindrical structure a4 is shaped using the aforementioned inner cavity shaping mold 80, the outer diameter of the folded edge a1 can be controlled at 2.5 mm.

[0128] In some implementations, see Figure 18 When the lower end face of the vertical cylindrical structure a4 after the inner cavity is shaped is flushed to make the lower end face flat, an end face shaping mold 90 is used. The end face shaping mold 90 includes a second die 901 and a second pressure block 902 arranged sequentially from bottom to top. The second die 901 has a second lower cavity 9011. An inner bushing 904 is provided in the second lower cavity 9011. The upper end face of the inner bushing 904 is flat. The outer wall of the inner bushing 904 is in contact with the inner wall of the second lower cavity 9011. The second pressure block 902 has a second upper cavity 9021, which is used to accommodate the flushing punch 903.

[0129] Furthermore, the bottom end of the punch 903 is an arc-shaped end 9031.

[0130] Specifically, when using the end-face shaping mold 90 to flush the lower end face of the shaped vertical cylindrical structure a4, the following steps are taken: placing the folded edge a1 between the second pressure block 902 and the second die 901 and pressing it tightly, so that the vertical cylindrical structure a4 is placed in the second lower cavity 9011, and the lower end face of the vertical cylindrical structure a4 is above the upper end face of the inner bushing 904. Then, the flushing punch 903 is pushed downward until the bottom end of the flushing punch 903 extends into the inner cavity of the vertical cylindrical structure a4 and continues to move downward a set distance until the arc-shaped end 9031 of the bottom end of the flushing punch 903 is below the upper end face of the inner bushing 904, so that the flushing punch 903 squeezes the inner wall of the vertical cylindrical structure a4, and the lower end face of the vertical cylindrical structure a4 and the upper end face of the inner bushing 904 fit together to form a plane.

[0131] It should be noted that, for reference Figure 17 Before the flushing treatment, the lower end face FF of the vertical cylindrical structure a4 may be uneven. After the flushing treatment, see [reference needed]. Figure 19 Its lower end face FF can be transformed into a flat plane to ensure that the lower end face is flush.

[0132] The sleeve structure obtained by the above preparation method has an integrally formed sleeve body and flange. The sleeve structure has high mechanical strength, mechanical stability and processing consistency, and is not prone to stress concentration, thus improving the stability of the bonding interface when the sleeve is combined with the glass.

[0133] The aforementioned sleeve structure achieves "weakly coupled" stress buffering, flow guiding, and positioning functions under the condition of miniature products, while ensuring the manufacturability of deep drawing forming of the sleeve and the weldability of the flange, thereby improving the glass sealing tightness and subsequent assembly reliability.

[0134] Example 2

[0135] See Figures 2-5 This embodiment discloses an electrode assembly 10, including a sleeve 103, an electrode post 101, and a glass ring 102;

[0136] The sleeve 103 includes a cylindrical body 1031, and a flange 1032 is formed at one end of the cylindrical body 1031; in some embodiments, the cylindrical body 1031 and the flange 1032 in the sleeve 103 can be integrally formed.

[0137] The pole post 101 is located inside the sleeve 103;

[0138] The sleeve 103 and the pole post 101 are heat-sealed together by a glass ring 102.

[0139] In the aforementioned electrode assembly 10, the sleeve 103 and the inner electrode post 101 are sealed together by a glass ring 102, which can effectively ensure the insulation and airtightness between the sleeve 103 and the electrode post 101. During the preparation, glass material can be filled inside the sleeve 103 and the electrode post 101 and melted at high temperature, thereby connecting the sleeve 103 and the electrode post 101 together by hot-melt glass.

[0140] In some methods, when preparing and sealing the electrode assembly, the electrode post 101 is placed in the sleeve 103, and glass raw material is placed between the electrode post 101 and the sleeve 103. The assembly is then sintered and sealed at a preset temperature. During sintering, the glass raw material melts and flows, contacting the sleeve and the electrode post. At the same time, the guide groove on the inner wall of the sleeve can control the flow of gas during the melting process and help the gas to be discharged, thereby sealing the electrode post and the sleeve together. Then, the glass raw material is cooled to solidify and form the final glass ring, thus obtaining the electrode assembly product.

[0141] See Figure 9 The following is a specific example illustrating the sealing process described above:

[0142] a1, See also Figure 9 In the middle a stage, a graphite jig is used to fix the sleeve 103 and the pole post 101, so that the pole post 101 is located inside the sleeve 103, and glass raw material aa is filled / placed between the pole post 101 and the sleeve 103 to form an assembly.

[0143] a2, see reference Figure 9 In stage b, the assembly is sent into a vacuum / inert atmosphere furnace for heating, which melts the glass raw material to form a glass fluid. Under the action of gravity, the glass fluid flows downward, and the air is squeezed out, thereby achieving full contact between the glass and the pole post 101 and the sleeve 103.

[0144] a3, see reference Figure 9 In stage c, the molten glass fluid slowly solidifies as the temperature decreases, forming molecular bonds at the contact surface between the sleeve 103 and the electrode post 101, thus forming a well-sealed structure – the electrode assembly 10. Understandably, the solidified glass fluid forms a glass ring 102.

[0145] In some embodiments, the pole post 101 is made of aluminum, or nickel, or a nickel-based alloy, and the sleeve 103 and the housing 20 are both made of stainless steel, for example, the sleeve 103 and the housing 20 are both made of 316L stainless steel.

[0146] The glass ring 102 can be made of lead-free borosilicate glass or lithium aluminum silicate glass.

[0147] In some embodiments, the outer diameter of the terminal 101 is 0.5 to 1.5 mm. For example, it can be 0.6 mm, 0.8 mm, or 1 mm, etc.; it is especially suitable for ultra-thin batteries.

[0148] In some embodiments, the pole post 101 is cylindrical or nearly cylindrical. For example, the middle part of the pole post 101 is slightly smaller than the two ends. Specifically, the outer diameter of the top and bottom surfaces of the pole post is slightly larger than the outer diameter of the middle part.

[0149] Understandably, the "outer diameter of the pole post" mentioned above refers to the outer diameter at any point between the two end faces of the pole post (including the end faces).

[0150] In some implementations, the height H2 of the pole post 101 is not greater than 0.8 mm, for example, it can be 0.725 mm.

[0151] For example, in some specific ways, the components in the electrode assembly 10 may be arranged as follows: the outer diameter of the pole post 101 is 1 mm and the height is 0.725 mm; the height of the glass ring 102 is 0.475 mm; the inner diameter of the cylinder 1031 in the sleeve 103 is 1.8 mm and the thickness is 0.15 mm; and the outer diameter of the flange 1032 is 2.6 mm.

[0152] The height of the sleeve 103 is the same as the height of the glass ring 102, and the top surface of the glass ring 102 is flush with the top surface of the sleeve 103, and the bottom surface of the glass ring 102 is flush with the bottom surface of the sleeve 103, so as to better ensure the integrity of the seal.

[0153] The electrode assembly described above has relatively small dimensions for both the posts and sleeves, making it particularly suitable for micro-thin batteries.

[0154] This embodiment also discloses a battery casing assembly, which includes a housing 20 and an electrode assembly 10, see reference. Figures 10-11 The electrode assembly 10 is welded to the housing. The housing 20 is provided with a mounting hole 2011. The cylinder 1031 is inserted into the mounting hole. The flange 1032 and the housing 20 are welded together by laser welding or resistance welding. A ring weld mark 2023 is formed at the connection between the flange 1032 and the housing 20.

[0155] Example 3

[0156] This embodiment discloses a quality traceability system. A unique product code is set on the surface of the flange 1032 of the sleeve 103. The quality traceability system is used to collect the product code and retrieve the production data corresponding to the product code from the production database to achieve traceability management.

[0157] The aforementioned production data can include raw material data, processing steps, process parameters (temperature, pressure, time, etc.), testing data, and finished product warehousing data for each component of the electrode assembly corresponding to the product code. All of the above production data is stored in the production database.

[0158] For example, the aforementioned process parameters can be process parameters such as temperature, pressure, and time in key processes such as sleeve stretching, sealing, and welding. The test data can be the results of dimensional inspections (inner diameter, outer diameter, height), airtightness testing, and insulation withstand voltage testing.

[0159] Each sleeve 103 has a unique product code, and each set of production data is associated with a corresponding product code to achieve unique traceability of a single product. Through the product code, it is possible to trace back to raw materials, process parameters, and test results, ensuring the verifiability of each product. This improves the level of quality management, reduces the risk of defective products flowing out, and improves the efficiency of anomaly analysis. It can also quickly locate the process link and responsible batch corresponding to defective products through backtracking queries, which is conducive to forming a complete quality file and meeting future customer audit and certification requirements.

[0160] In the above system, the product code is set on the surface of the flange 1032 (e.g., the product code is set on...). Figure 3 The flange is located at W1 on the surface of the 1032 flange, rather than on the outer wall or inside of the battery casing. This design better ensures the airtightness and structural strength of the battery casing and does not occupy the internal space of the casing, thus achieving space optimization and meeting the requirements of high-end battery packaging.

[0161] The product codes mentioned above can be laser-engraved, QR codes, or RFID tags.

[0162] In some implementations, the product code can be formed on the outer surface (upper / lower surface) of the flange 1032 by laser marking or QR code etching to achieve unique identification at the individual piece level.

[0163] The thickness of the aforementioned flange 1032 is not less than 0.8 times the thickness of its raw material, that is, the thickness of the flange 1032 is not less than 0.8 times the thickness of the sheet material used to prepare the sleeve by stretch forming process.

[0164] In some implementations, the quality traceability system includes a data acquisition module and a server, the server containing a production database;

[0165] The production database is used to store production data. The production data is the production data of each electrode assembly where the sleeve is located. The production data corresponds to the product code, that is, each set of production data is associated with a product code.

[0166] The aforementioned production data can include raw material data, processing procedure data, process parameters, testing data, finished product warehousing data, etc. The aforementioned production data can be obtained through manual or automatic collection methods. After obtaining the aforementioned production data, it is necessary to transfer the production data to the production database for storage.

[0167] Understandably, when the above production data is obtained through automatic acquisition, the production testing equipment can be connected to the production database to automatically upload the production batch number, process parameters, test data, and other production data collected by the production testing equipment to the production database.

[0168] The aforementioned data acquisition module is used to acquire product codes; for example, the data acquisition module can be a barcode scanning device.

[0169] By using the product code as a search criterion in the production database, the corresponding production data can be retrieved to achieve traceability management.

[0170] In some implementations, the quality traceability system also includes a defect analysis module, which compares product testing data with standard data parameters. If the comparison result does not meet the qualification standard, the batch of products is automatically marked and a defect analysis report is generated.

[0171] In some cases, the quality traceability system can also be integrated with the enterprise's ERP system to achieve traceability management of the supply chain and after-sales process.

[0172] The aforementioned quality traceability system enables unique identification and data traceability of products throughout the entire process from raw materials, processing, testing to finished product assembly, facilitating rapid location of defects and improving production yield, product consistency, and quality management efficiency.

[0173] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention. That is, any number of embodiments can be combined to meet the needs of different application scenarios. All of these are within the protection scope of this application and will not be described in detail here.

[0174] It should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A hollow sleeve, characterized in that, The sleeve includes a cylindrical body, one end of which is formed with a flange; a guide groove is provided on the inner wall of the cylindrical body, the guide groove is arranged around the axis of the cylindrical body, the inside of the sleeve is used to accommodate the pole post, the sleeve and the pole post are sealed by melting glass ring, and the guide groove can provide a gas escape path during the melting or flow stage of the glass ring; The guide groove is a continuous annular groove; or, multiple guide grooves are provided on the inner wall of the cylinder, and the multiple guide grooves are evenly distributed circumferentially around the axis of the cylinder to form an annular shape. The depth of the guide groove is 0.02 to 0.08 mm; the width of the guide groove is 0.05 to 0.2 mm.

2. The hollow sleeve according to claim 1, characterized in that, The cylinder and the flange are connected by an arc-shaped fillet with a radius of 0.02 to 0.1 mm.

3. The hollow sleeve according to claim 1, characterized in that, The inner wall of the cylinder near the flange end is a linear stress buffer zone.

4. The hollow sleeve according to claim 3, characterized in that, The linear stress buffer is corrugated, with an amplitude of 0.02–0.06 mm and a pitch of 0.1–0.3 mm.

5. The hollow sleeve according to claim 3, characterized in that, The linear stress buffer zone is a thinning zone, and the thinning depth of the thinning zone is 0.1 to 0.4 times the thickness of the cylinder.

6. The hollow sleeve according to claim 1, characterized in that, The flange has a first surface and a second surface arranged opposite to each other. The first surface is provided with a first groove. The distance between the first surface and the second surface is a first thickness. The depth of the first groove is 0.2 to 0.4 times the first thickness.

7. The hollow sleeve according to claim 6, characterized in that, The first thickness is 0.12 to 0.18 mm.

8. The hollow sleeve according to claim 1, characterized in that, The inner diameter of the cylinder is 0.5 to 2.25 mm.

9. The hollow sleeve according to claim 1, characterized in that, The cylinder and the flange are integrally formed.

10. The method for preparing the hollow sleeve according to any one of claims 1-9, characterized in that, Includes the following steps: The sleeve is prepared by stretch forming process, so that the sleeve body and the flange are integrally formed. A guide groove is machined on the inner wall of the cylinder; The sleeve with the guide groove is annealed.

11. An electrode assembly, characterized in that, It includes a sleeve, an electrode post, and a glass ring as described in any one of claims 1-9, wherein the electrode post is located inside the sleeve; the sleeve and the electrode post are sealed together by the glass ring.

12. A quality traceability system for an electrode assembly as described in claim 11, characterized in that, A unique product code is set on the flange. The quality traceability system is used to collect the product code and retrieve the production data corresponding to the product code from the production database to achieve traceability management.

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