Electrode assembly and preparation method

Abstract

The invention relates to an electrode assembly and a preparation method, and the method comprises the steps: providing a pole and a sleeve, the sleeve comprises a cylinder body, and one end of the cylinder body is provided with a flanging flange; the pole and the sleeve are positioned, so that the pole is located in the sleeve, and a glass ring is arranged between the pole and the sleeve to form an assembly; the assembly is placed in a heating furnace to be heated, so that the glass ring is melted, and the pole and the sleeve are sealed together; carrying out annealing treatment on the assembly body; and after annealing treatment, cooling the assembly until the assembly is cooled to room temperature, so that the molten glass ring is completely cured. The invention also discloses an electrode assembly. According to the invention, the preparation efficiency and quality of the electrode assembly can be effectively improved, and the sealing reliability and airtightness of the electrode assembly are ensured.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electrode assembly and its preparation method. Background Technology

[0002] The electrode assembly in a battery is mounted on the casing to electrically connect the internal battery cells and external electrical components. The electrode assembly typically includes terminals, and an insulating component is required between the terminals and the casing to ensure insulation and sealing. Plastic sheets are commonly used as these insulating components; however, plastic components 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 casing and failing to meet the safety requirements of high-power charging and discharging conditions and long-term use safety needs. To solve these problems, glass can be used to replace the plastic sheet for glass sealing of the terminals. However, this sealing structure has low manufacturing efficiency and unstable sealing quality, failing to meet production requirements. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to improve the preparation efficiency and preparation quality of electrode components in the prior art.

[0004] To address the aforementioned technical problems, this invention provides a method for preparing an electrode assembly, comprising:

[0005] A pole and a sleeve are provided, the sleeve comprising a cylindrical body having a flanged flange at one end;

[0006] The pole and the sleeve are positioned such that the pole is located in the sleeve, and a glass ring is placed between the pole and the sleeve to form an assembly;

[0007] The assembly is placed in a heating furnace for heating treatment to melt the glass ring and seal the pole and the sleeve together;

[0008] The assembly is then subjected to annealing.

[0009] After annealing, the assembly is cooled to room temperature so that the molten glass ring is completely solidified.

[0010] In one embodiment of the present invention, when positioning the pole post and the sleeve, the pole post and the sleeve are arranged coaxially.

[0011] In one embodiment of the present invention, the method of heating the glass ring to melt and seal the pole and the sleeve together includes: raising the temperature of the heating furnace to 420-480°C at a rate of 5-15°C / min and holding it at that temperature for a first time, so that the glass ring melts and flows and wets the outer wall of the pole and the inner wall of the sleeve, thereby sealing the pole and the sleeve together through the molten glass ring.

[0012] In one embodiment of the present invention, the first duration is 3 to 30 minutes.

[0013] In one embodiment of the present invention, the method for annealing the assembly includes: reducing the temperature of a heating furnace to 250-350°C at a rate of 1-5°C / min, and holding the temperature for a second duration.

[0014] In one embodiment of the present invention, the second duration is 10 to 60 minutes.

[0015] In one embodiment of the present invention, before placing the assembly in a heating furnace for heating treatment, the heating furnace is also subjected to a vacuum treatment. After the vacuum treatment, the vacuum degree inside the heating furnace is [missing information]. Torr.

[0016] In one embodiment of the present invention, before the assembly is placed in a heating furnace for heating treatment, an inert gas is introduced into the heating furnace to form an inert atmosphere.

[0017] In one embodiment of the present invention, before providing the electrode post, a metal transition layer is deposited on the surface of the electrode post, the thickness of the metal transition layer being 10 to 200 nm.

[0018] In one embodiment of the present invention, the metal transition layer is made of one or more materials selected from titanium and chromium.

[0019] In one embodiment of the present invention, the glass ring is made of borosilicate glass.

[0020] In one embodiment of the present invention, the sleeve is made of stainless steel, and the pole is made of one or more of aluminum, nickel, and nickel-based alloys.

[0021] The present invention also discloses an electrode assembly, which is prepared by any of the preparation methods described above.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] The electrode assembly and its preparation method described in this invention can effectively improve the preparation efficiency and quality of the electrode assembly, and ensure the sealing reliability and airtightness of the electrode assembly. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram of the fabrication process of the electrode assembly of the present invention;

[0026] Figure 2 This is a schematic diagram of the electrode assembly of the present invention undergoing a sealing test;

[0027] Figure 3 This is a schematic diagram of the electrode assembly of the present invention;

[0028] Figure 4 yes Figure 3 Another structural schematic diagram of the middle electrode assembly;

[0029] Figure 5 yes Figure 3 Top view of the middle electrode assembly;

[0030] Figure 6 yes Figure 5 Sectional view at point AA;

[0031] Explanation of reference numerals in the instruction manual:

[0032] 10. Electrode assembly; 101. Electrode post; 102. Glass ring; 103. Sleeve; 1031. Cylinder body; 1032. Flanged flange; Detailed Implementation

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Example 1

[0037] See Figure 1 This embodiment discloses a method for preparing an electrode assembly 10, which includes the following steps:

[0038] Step S1: Provide a metal pole post 101 and a sleeve 103. The sleeve 103 includes a cylindrical body 1031, and a flange 1032 is formed at one end of the cylindrical body 1031.

[0039] Step S2: Position the pole post 101 and the sleeve 103 so that the pole post 101 is located in the sleeve 103, and set a glass ring 102 between the pole post 101 and the sleeve 103 to form an assembly.

[0040] The glass ring 102 mentioned above can be a pre-made annular glass body, or glass powder or granules. It needs to be dried before being inserted into the pole post 101 and the sleeve 103.

[0041] Step S3: Place the assembly in a heating furnace for heating treatment so that the glass ring 102 melts and heat-seales the pole post 101 and the sleeve 103 together;

[0042] Step S4: Anneal the assembly;

[0043] Step S5: After annealing, the assembly is cooled to room temperature so that the molten glass ring 102 is completely solidified, thereby preparing the electrode assembly 10.

[0044] After step S5, the obtained electrode assembly needs to be removed and subjected to visual inspection (no cracks, no obvious bubbles), airtightness test, and electrical insulation test.

[0045] The above-mentioned airtightness test can be performed using helium detection or pressure difference method.

[0046] The above preparation method improves the reliability of the connection between the glass and the sleeve / terminal, allowing for a reliable seal between the sleeve and the terminal through the glass ring. This enhances the sealing insulation and airtightness between the sleeve and the terminal. The annealed and cured glass ring exhibits excellent high-temperature resistance and airtightness, ensuring the reliability of the connection structure even after long-term use. The above preparation method also boasts high efficiency and effectively shortens processing time.

[0047] The airtightness of the electrode assembly obtained by the above preparation method was tested using a helium leak detector. For the sealing test equipment, please refer to [link / reference needed]. Figure 2 The helium leakage rate is no greater than The electrical insulation test shows that the leakage current is less than 1μA under 500V DC.

[0048] The design of the flange 1032 in the sleeve 103 facilitates clamping and positioning, and enhances the mechanical strength and interface stability of the sealing area. In addition, when welding the electrode assembly and the battery casing, the flange can be used to weld the casing. During the welding process, the flange has the following functions: first, it acts as a thermal buffer zone for the weld, effectively dispersing welding stress; second, it enhances the mechanical bonding strength between the weld and the edge of the casing, thereby improving the sealing performance and reliability of the overall structure; and third, it can reduce welding deformation and improve welding stability.

[0049] To facilitate positioning and welding, positioning marks can be set on the flange 1032 of the sleeve 103 to facilitate automated alignment and welding on the production line.

[0050] In some embodiments, when positioning the pole post 101 and the sleeve 103, the pole post 101 is located in the sleeve 103, and the pole post 101 and the sleeve 103 are coaxially arranged.

[0051] In some embodiments, the sleeve 103 can be integrally stretched. For example, the sleeve 103 is made of stainless steel. The stainless steel sheet can be punched, pre-annealed, and then pre-stretched, re-stretched, shaped, and flanged leveled in a multi-station deep drawing die to obtain a hollow sleeve structure. After the sleeve is prepared, it can also be subjected to ultrasonic degreasing, acid pickling and neutralization, and plasma cleaning to remove contaminants from the sleeve surface, thereby greatly improving the adhesion of subsequent glass bonding.

[0052] In some embodiments, the method of heating the glass ring 102 to melt and seal the pole post 101 and the sleeve 103 together includes raising the temperature of the furnace to 420-480°C at a rate of 5-15°C / min and holding it at that temperature for a first time, so that the glass ring 102 melts and flows and fully wets the outer wall of the pole post 101 and the inner wall of the sleeve 103, thereby sealing the pole post 101 and the sleeve 103 together through the molten glass ring 102.

[0053] The initial duration can be 3 to 30 minutes. Alternatively, it can be 5 to 15 minutes.

[0054] Understandably, "wetting" refers to the phenomenon where liquid raw materials (such as glass) in a molten state spread and cover the surface of the sealed component (such as pole, sleeve, etc.) during sealing. Wetting indicates that a dissolution and diffusion process has occurred between the liquid raw material and the surface of the sealed component, forming a good adhesion and bonding interface.

[0055] By using the above-mentioned temperature control method, it can be ensured that the glass raw material can fully bond with the surface of the pole post 101 and the sleeve 103, thereby forming a dense and airtight bonding interface, ensuring excellent airtightness, and thus ensuring the airtightness and insulation reliability of the final product.

[0056] For example, a method of heating the glass ring to melt it and seal the pole post 101 and the sleeve 103 together includes raising the temperature of the furnace to 450°C at a rate of 5 to 15°C / min and holding it at that temperature for 5 to 15 minutes (first duration) to allow the glass ring 102 to melt and flow and fully wet the outer wall of the pole post 101 and the inner wall of the sleeve 103.

[0057] In some embodiments, the method for annealing the assembly includes reducing the temperature of the furnace to 250-350°C at a rate of 1-5°C / min and holding it at that temperature for a second duration.

[0058] The second duration can be 10 to 60 minutes. Further, the second duration can be 10 to 30 minutes.

[0059] The above annealing process can effectively improve the stability of glass ring curing, thereby ensuring the structural stability of the final product.

[0060] An exemplary method for annealing an assembly includes: reducing the temperature of a heating furnace to 300°C at a rate of 1–5°C / min, holding at that temperature for 10–30 minutes (second duration), and then cooling to room temperature.

[0061] In some embodiments, before placing the assembly in the heating furnace for heat treatment, the furnace is also evacuated to ensure that the heat treatment is carried out in a vacuum atmosphere. After evacuation, the vacuum level inside the heating furnace is [missing information]. ~ Torr.

[0062] By using vacuuming, the oxygen content inside the furnace can be reduced, thus decreasing the oxidation reaction. The aforementioned vacuum level control range can better meet the requirements for heating rate and heating temperature.

[0063] or,

[0064] In other embodiments, before the assembly is placed in a heating furnace for heat treatment, an inert gas is introduced into the heating furnace to create an inert atmosphere so that the heat treatment is carried out in an inert atmosphere to prevent metal parts such as sleeve 103 and pole 101 from oxidizing in a high-temperature environment.

[0065] The inert gas mentioned above can be argon.

[0066] In some embodiments, before providing the electrode post 101, a metal transition layer is deposited on the surface of the electrode post 101. The thickness of the metal transition layer is 10 to 200 nm, specifically 20 nm, 50 nm, 100 nm, 150 nm, 200 nm, etc., to improve the bonding reliability (bonding strength) between the surface of the metal electrode post 101 and the glass ring 102, thereby forming a dense and airtight interface.

[0067] Furthermore, the metal transition layer is made of one or more materials selected from titanium and chromium.

[0068] Before the metal transition layer is deposited on the electrode 101, ultrasonic degreasing, acid pickling and neutralization and plasma cleaning can be performed to remove contaminants on the electrode surface, thereby greatly improving its adhesion to the subsequent metal transition layer.

[0069] In some embodiments, an oxide film layer can be formed on the electrode surface before depositing the metal transition layer to further enhance its adhesion to the metal transition layer. That is, the electrode surface is treated to form an oxide film layer and a metal transition layer sequentially before being thermally sealed with a glass ring.

[0070] The aforementioned oxide film can be a nickel oxide layer or an aluminum oxide layer, and the thickness of the oxide film can be 10–200 nm. For example, it can be 50 nm, 100 nm, 150 nm, etc.

[0071] In some embodiments, the glass ring 102 is made of borosilicate glass, which can be a low-melting-point glass, for example, with a melting point of 380 to 520°C, or further, with a melting point of 420 to 480°C, specifically 430°C, 440°C, 450°C, 470°C, etc.

[0072] Sleeve 103 can be made of stainless steel, and in some preferred embodiments, sleeve 103 can be made of 316L stainless steel.

[0073] The pole piece 101 can be made of one or more of aluminum, nickel, and nickel-based alloys.

[0074] The above preparation method enables stable and controllable glass-metal sealing in the factory, which significantly improves the airtightness, temperature resistance and long-term reliability of electrode assembly products. While improving sealing reliability, it also facilitates mass production control and significantly reduces the process risks of on-site assembly.

[0075] The above preparation method is applicable to various micro lithium batteries, wearable device batteries, and other applications requiring highly reliable hermetic extraction, and has significant industrial application value in improving product lifespan, quality consistency, and environmental friendliness. It is particularly suitable for the preparation of small-sized electrode components.

[0076] Example 2

[0077] See Figures 3-6 This embodiment discloses an electrode assembly 10, which can be prepared using the preparation method described in Embodiment 1.

[0078] The electrode assembly 10 mentioned above includes a sleeve 103, an electrode post 101, and a glass ring 102;

[0079] The sleeve 103 includes a cylinder 1031, and a flange 1032 is formed at one end of the cylinder 1031;

[0080] The pole post 101 is located inside the sleeve 103;

[0081] The sleeve 103 and the pole post 101 are heat-sealed together by a glass ring 102.

[0082] 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.

[0083] Furthermore, the cylinder 1031 and the flange 1032 in the sleeve 103 are integrally formed structures, which can be prepared by deep drawing and stamping process without welding or splicing, which is more conducive to improving structural strength and consistency.

[0084] In some embodiments, the sleeve 103 has a wall thickness of 50 to 250 μm, for example, it can be 60, 80, 100, 150, 200 μm, etc., and is a thin-walled part.

[0085] In some designs, the outer diameter D2 of the cylinder 1031 is 1.35 to 2.25 mm. For example, the outer diameter of the cylinder 1031 can be 1.5 mm, 2 mm, etc.

[0086] Furthermore, the outer diameter D1 of the flange 1032 is 2 to 3 mm, for example, it can be 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, etc.

[0087] In some embodiments, the sleeve 103 may be made of stainless steel, and in some preferred embodiments, the sleeve 103 may be made of 316L stainless steel.

[0088] In some implementations, such as Figure 6 As shown, the height H1 of the glass ring 102 is no greater than 0.5 mm; for example, the height H1 of the glass ring 102 can be 0.475 ± 0.03 mm. This is suitable for ultra-thin battery designs. Furthermore, 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, to better ensure the integrity of the seal.

[0089] The inner diameter of the glass ring 102 can be 0.5 to 1.5 mm; for example, the inner diameter of the glass ring 102 can be 0.6 mm, 0.9 mm, 1 mm, 1.2 mm, 1.3 mm, etc.

[0090] The outer diameter of the glass ring 102 can be 1.2 to 2.1 mm, for example, the outer diameter can be 1.35±0.03 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, etc.

[0091] It is understandable that the "inner diameter of the glass ring" mentioned above refers to the inner diameter at any point between the two end faces of the glass ring (including the end faces), and similarly, the "outer diameter of the glass ring" mentioned above refers to the outer diameter at any point between the two end faces of the glass ring (including the end faces).

[0092] 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.

[0093] 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 101 is slightly larger than the outer diameter of the middle part.

[0094] In some embodiments, the pole 101 may be made of one or more of aluminum (Al), nickel (Ni), and nickel-based alloys.

[0095] In some embodiments, to improve the bonding strength between the glass ring 102 and the electrode 101, a metal transition layer is deposited on the surface of the electrode 101, so that the electrode 101 and the glass ring 102 are bonded together through the metal transition layer. The above structure can significantly improve the bonding strength and interface stability of the metal electrode and the glass ring, thereby improving the airtightness, thermal cycling stability and reliability of the structure.

[0096] For example, the thickness of the metal transition layer is 10 to 200 nm, specifically 20 nm, 50 nm, 100 nm, 150 nm, 200 nm, etc.

[0097] Furthermore, the metal transition layer is made of one or more materials selected from titanium (Ti) and chromium (Cr).

[0098] In some embodiments, an oxide film may be formed on the electrode surface before depositing the metal transition layer, to further enhance its adhesion to the metal transition layer. That is, an oxide film and a metal transition layer are formed sequentially on the electrode surface.

[0099] The oxide film layer can be a nickel oxide layer or an aluminum oxide layer, and the thickness of the oxide film layer can be 10-200 nm; for example, it can be 50 nm, 100 nm, 150 nm, etc.

[0100] The electrode assembly described above has high airtightness, heat resistance and long-term reliability, and is particularly suitable for use in electrode assemblies in lithium-ion battery casings.

[0101] This embodiment also discloses a battery casing assembly, which includes a casing and an electrode assembly 10. The electrode assembly 10 is welded to the casing, and the casing is provided with mounting holes. A cylindrical body 1031 is inserted into the mounting holes. A flange 1032 and the casing are welded together by laser welding or spot welding, and an annular weld mark is formed at the connection between the flange 1032 and the casing.

[0102] 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.

[0103] 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 method for preparing an electrode assembly, characterized in that, include: A pole and a sleeve are provided, wherein the outer diameter of the top and bottom surfaces of the pole is larger than the middle outer diameter, and the sleeve includes a cylindrical body, one end of which is formed with a flange. The pole and the sleeve are positioned such that the pole is located in the sleeve, and a glass ring is provided between the outer wall of the pole and the inner wall of the sleeve to form an assembly. The glass ring is a pre-made annular glass body or is filled with glass powder. The assembly is placed in a heating furnace for heating treatment to melt the glass ring and seal the pole and the sleeve together; The assembly is then subjected to annealing. After annealing, the assembly is cooled to room temperature so that the molten glass ring is completely solidified. The top surface of the solidified glass ring is flush with the top surface of the sleeve, and the bottom surface of the glass ring is flush with the bottom surface of the sleeve. The flange is used for welding to the battery casing.

2. The method for preparing the electrode assembly according to claim 1, characterized in that, When positioning the pole and the sleeve, the pole and the sleeve are arranged coaxially.

3. The method for preparing the electrode assembly according to claim 1, characterized in that, The method of heating the glass ring to melt it and seal the pole and the sleeve together includes: raising the temperature of the heating furnace to 420-480°C at a rate of 5-15°C / min and holding it at that temperature for a first time, so that the glass ring melts and flows and wets the outer wall of the pole and the inner wall of the sleeve, thereby sealing the pole and the sleeve together through the molten glass ring.

4. The method for preparing the electrode assembly according to claim 3, characterized in that, The first duration is 3 to 30 minutes.

5. The method for preparing the electrode assembly according to claim 1, characterized in that, The method for annealing the assembly includes: reducing the temperature of the heating furnace to 250-350°C at a rate of 1-5°C / min and holding it at that temperature for a second duration.

6. The method for preparing the electrode assembly according to claim 5, characterized in that, The second duration is 10 to 60 minutes.

7. The method for preparing the electrode assembly according to claim 1, characterized in that, Before placing the assembly in the heating furnace for heating treatment, the heating furnace is also evacuated. After evacuation, the vacuum level inside the heating furnace is [missing value]. Torr.

8. The method for preparing the electrode assembly according to claim 1, characterized in that, Before placing the assembly in a heating furnace for heating treatment, an inert gas is introduced into the heating furnace to form an inert atmosphere.

9. The method for preparing the electrode assembly according to claim 1, characterized in that, Before providing the electrode post, a metal transition layer is deposited on the surface of the electrode post, the thickness of which is 10-200 nm.

10. The method for preparing the electrode assembly according to claim 9, characterized in that, The metal transition layer is made of one or more materials selected from titanium and chromium.

11. The method for preparing the electrode assembly according to claim 1, characterized in that, The glass ring is made of borosilicate glass.

12. The method for preparing the electrode assembly according to claim 1, characterized in that, The sleeve is made of stainless steel, and the pole is made of one or more of aluminum, nickel, and nickel-based alloys.

13. An electrode assembly, characterized in that, It is prepared by the preparation method described in any one of claims 1-12.

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