A battery composite current collector tab welding piece and a preparation method thereof

Abstract

The present application belongs to the technical field of lithium battery current collector welding, and provides a battery composite current collector tab welding piece and a preparation method thereof. First, polydopamine microsphere powder is prepared, and copper formate precursor is loaded on the surface of the microspheres to form copper formate hybrid microspheres; then, core-shell bridging microparticles treated with imidazole silane are prepared; subsequently, metal powder, a binder, a solvent, copper formate hybrid microspheres and core-shell bridging microparticles are mixed to obtain a metal slurry, which is coated on the tab welding site of the composite current collector, and then lamination, solidification and ultrasonic welding are performed to obtain the battery composite current collector tab welding piece. The functional component with the functions of precursor activation and core-shell bridging is introduced at the welding interface, which is conducive to the construction of a stable conductive connection interface and is suitable for battery composite current collector tab welding.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery current collector welding technology, and relates to a battery composite current collector electrode welding component and its preparation method. Background Technology

[0002] As electrochemical energy storage devices such as lithium-ion batteries develop towards higher energy density, lighter weight, and higher safety, composite current collectors are gradually becoming an important development direction in the field of battery materials due to their advantages of weight reduction, increased specific energy, and improved overall battery performance. Composite current collectors are typically composed of a polymer insulating layer (mostly polypropylene or polyethylene terephthalate) and a metal conductive layer, and their structure differs significantly from traditional metal foil current collectors. During battery manufacturing, the tab area needs to form a stable connection with external conductive components; therefore, the fabrication quality of the composite current collector tab weld directly affects the battery's conductivity, connection reliability, and subsequent operational stability.

[0003] However, the metal layer on the surface of composite current collectors is relatively thin, and it contains a non-metallic support layer, causing it to exhibit different interface response characteristics compared to traditional metal current collectors during welding. If conventional welding methods are used directly, problems such as insufficient conductive contact in the welding area, unstable interface bonding, localized damage to the welding area, and poor connection consistency are likely to occur. Especially under multi-layer stacking conditions, the transfer and distribution of welding energy between different layers becomes more complex, further increasing the technological difficulty of welding the tabs of composite current collectors.

[0004] In the existing technology, the solutions for welding composite current collector tabs are mostly focused on adjusting welding equipment parameters, optimizing welding methods, or reinforcing the tab area with simple conductive materials. However, these solutions still have shortcomings such as a single welding interface construction method and insufficient coupling between functional components and the welding process, making it difficult to balance interface conductivity, welding bonding, and process adaptability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a battery composite current collector electrode tab welding component and its preparation method. First, copper formate hybrid microspheres and core-shell bridging microparticles are prepared, then mixed with metal powder, binder and solvent to form a metal slurry, which is then coated onto the electrode tab area of ​​the composite current collector to be welded. After stacking, curing and ultrasonic welding, the electrode tab welding component is obtained, thereby meeting the needs of actual production.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a battery composite current collector tab welding component, comprising a composite current collector tab and a welding connection layer, wherein the welding connection layer is disposed on the welding portion of the composite current collector tab and is formed by curing a metal slurry and ultrasonic welding, wherein the metal slurry comprises metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles.

[0008] Secondly, the present invention provides a method for preparing a battery composite current collector tab welding component, the method comprising:

[0009] S1, dopamine hydrochloride, Tris-HCl buffer and ethanol aqueous solution are mixed, pH is adjusted and then reacted to obtain polydopamine microsphere powder;

[0010] S2, copper formate tetrahydrate, anhydrous ethanol and deionized water are mixed and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution to obtain copper formate hybrid microspheres.

[0011] S3, copper powder, polyvinylpyrrolidone, ascorbic acid and ethylene glycol are mixed to obtain a suspension, tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol and glacial acetic acid are mixed to obtain a metal salt solution, the metal salt solution is added dropwise to the suspension and sodium borohydride aqueous solution is added dropwise to react and perform heat aging treatment to obtain Cu@Sn-Bi core-shell microparticles;

[0012] S4, N-imidazolium propyltrimethoxysilane is added to an aqueous ethanol solution, the pH is adjusted and the reaction is carried out to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles are added to the imidazolium silane oligomer solution and stirred to obtain core-shell bridging microparticles.

[0013] S5, metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles are placed in a planetary mixer and stirred to obtain a metal slurry. The metal slurry is coated on the electrode tab part of the composite current collector to be welded, stacked and cured to obtain a cured stack. The cured stack is ultrasonically welded to obtain a battery composite current collector electrode tab welded part.

[0014] The preparation method specifically includes:

[0015] S1, mix dopamine hydrochloride, Tris-HCl buffer solution and ethanol aqueous solution, add ammonia dropwise to adjust pH to 8.3-8.8, stir for 5-8 hours, after the reaction is completed, centrifuge, wash, dry and grind to obtain polydopamine microsphere powder;

[0016] S2, copper tetrahydrate, anhydrous ethanol and deionized water are mixed and dispersed, and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution and dispersed evenly. The mixture is then distilled under reduced pressure and dried under vacuum to obtain copper formate hybrid microspheres.

[0017] S3, copper powder, polyvinylpyrrolidone, ascorbic acid and ethylene glycol are mixed to obtain a suspension, tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol and glacial acetic acid are mixed to obtain a metal salt solution, the metal salt solution is added dropwise to the suspension, stirred at 60-85℃ and sodium borohydride aqueous solution is added dropwise, and the reaction is continued for 30-90 min. After the reaction is completed, the mixture is filtered, washed and dried, and heat-cured under a nitrogen atmosphere to obtain Cu@Sn-Bi core-shell microparticles;

[0018] S4, N-imidazolium propyltrimethoxysilane was added to an aqueous ethanol solution, and glacial acetic acid was added dropwise to adjust the pH to 4.0-5.5. The reaction was carried out for 0.5-2 hours to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles were added to the imidazolium silane oligomer solution and stirred for 1-3 hours. The temperature was raised to 50-70℃ and stirring was continued for 1-2 hours. Then, the mixture was filtered, washed, and dried to obtain core-shell bridging microparticles.

[0019] S5, metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles are placed in a planetary mixer and stirred to obtain a metal slurry. The metal slurry is coated on the electrode tab part of the composite current collector to be welded, stacked and cured to obtain a cured stack. The cured stack is ultrasonically welded to obtain a battery composite current collector electrode tab welded part.

[0020] The phenolic hydroxyl, amino, and imine groups on the surface of polydopamine microspheres can bind with copper ions, fixing the copper formate-AMP (2-amino-2-methyl-1-propanol) precursor on the surface and near-surface region of the microspheres. After the metal slurry solidifies, the precursor is distributed in the gaps between metal powder particles, particle contact boundaries, and the contact area between the particles and the metal layer on the surface of the composite current collector. During ultrasonic welding, the interface undergoes compaction, friction, and localized temperature rise under pressure and high-frequency vibration. The oxide layer on the particle surface ruptures, the rough peaks collapse, and the actual contact area increases. The copper formate-AMP precursor decomposes in the contact area and generates nascent copper. The nascent copper is deposited in the micropores between particles and the interfacial gaps, filling unclosed areas, increasing the continuous metal contact area, and reducing intermittent contact between particles and interfaces.

[0021] AMP, as an amino-containing alcohol ligand, has a dual function: firstly, the amino group in AMP forms a copper-amine coordination complex with divalent copper ions, improving the dispersion stability of copper formate in solution and preventing premature crystallization and coarse particle formation during impregnation; secondly, AMP participation in coordination lowers the onset temperature of subsequent thermal decomposition of copper formate, making it more suitable for decomposition under the localized thermal field conditions of ultrasonic welding. When polydopamine microspheres are added to the composite precursor solution, the abundant catechol groups and amino groups on the surface of PDA (polydopamine) microspheres undergo coordination adsorption with divalent copper ions through chelation, causing the copper formate-AMP complex to be uniformly anchored on the surface and within the pores of the PDA microspheres. During welding, copper formate decomposes thermally to generate highly active copper nanoparticles, while PDA simultaneously carbonizes to form a conductive carbon framework. Together, they construct a copper-carbon composite conductive network at the welding interface. The gaseous byproducts generated during decomposition also provide reducing protection to the interface, reducing oxidation of the copper surface during welding and facilitating the formation of a pure metal-metal contact.

[0022] In Cu@Sn-Bi core-shell microparticles, the copper core constitutes the main conductive phase, while the Sn-Bi shell forms the interfacial bridging phase. N-Imidazolylpropyltrimethoxysilane undergoes hydrolysis and condensation in an ethanol-water system, forming a surface layer containing silanol and siloxane bonds. The imidazole groups undergo coordination adsorption with the copper surface, and the oligomeric siloxane layer adheres to the outer surface of the core-shell particles. This surface layer restricts further oxidation of the particles and weakens direct agglomeration between particles during the slurry preparation and curing stages. During ultrasonic welding, the Sn-Bi shell first undergoes localized plastic deformation and spreading, entering the voids between copper powder particles, between copper powder and the metal layer on the composite current collector surface, and between adjacent contact points, shortening the particle spacing and expanding the contact boundary. The Sn in the shell then diffuses and reacts with adjacent copper, forming a Cu-Sn connecting phase, transforming the original dispersed contact points into continuous bridging regions.

[0023] During the aging process, the treatment temperature is higher than the melting point of the Sn-Bi eutectic alloy. At this temperature, the Sn-Bi shell partially melts, allowing Sn and Bi atoms to fully interdiffused to form a uniform eutectic or near-eutectic alloy structure. Simultaneously, a thin layer of intermetallic compound forms at the interface between the Sn-Bi shell and the copper core, enhancing the shell-core bonding force. During ultrasonic welding, the local temperature at the interface rises rapidly, and the Sn-Bi alloy shell undergoes eutectic melting. Under welding pressure, the liquid alloy rapidly wets and fills the microscopic gaps and irregular cavities between the copper surfaces. After cooling and solidification, a Sn-Bi metallurgical weld joint is formed, achieving transient liquid phase diffusion welding.

[0024] When Cu@Sn-Bi core-shell microparticles are added to an imidazole silane oligomer solution, the silanol oligomers are anchored to the surface of the microparticles through the following mechanisms: (1) the silanol groups undergo dehydration condensation with the metal oxides / hydroxides on the surface of the microparticles to form covalent bonds; (2) the nitrogen atoms in the imidazole groups have a strong coordination ability to the surfaces of transition metals such as copper and tin, forming coordination bonds, which further enhances the bonding between the silane layer and the matrix, forming a dense and ordered imidazole functionalized silane thin layer on the surface of the microparticles. In the welding process, the imidazole groups of the core-shell bridging microparticles can coordinate with the exposed copper current collector surface at the welding interface, establishing a molecular-level chemical bridge between the slurry particles and the current collector metal layer, enhancing the interfacial bonding force. At the same time, the silane layer partially decomposes during the welding process, releasing fresh Sn-Bi alloy surface for liquid phase welding, which plays a role in stabilizing the weld joint structure at the interface. In addition, the imidazole groups have corrosion inhibition function, which can inhibit the oxidation corrosion of the copper and Sn-Bi surfaces during the storage and curing process before welding, maintaining the welding activity of the metal surface.

[0025] During ultrasonic welding, the high-frequency vibration of the welding head generates intense friction and localized plastic deformation at the interface of the laminated plates, and the interface temperature can rise in a very short time. In this localized thermal field, the copper formate in the copper formate hybrid microspheres decomposes, generating a large number of highly active copper nanoparticles in situ. These nanoparticles are rapidly sintered under the combined action of welding pressure and ultrasonic energy, forming a metallurgical bond with the current collector metal layer. At the same time, PDA carbonization forms a conductive carbon skeleton, establishing a multidimensional conductive network. The Sn-Bi alloy shell of the core-shell bridging microparticles undergoes eutectic melting, and the liquid alloy wets and fills the microscopic gaps at the interface. After cooling, a dense metallurgical weld is formed, and the copper core remains solid, providing structural support. Imidazole groups form molecular bridges at the interface through coordination, enhancing the chemical bonding force of the metal-metal interface, thereby continuously strengthening the interface bonding throughout the welding heating process and significantly widening the welding process window.

[0026] As a preferred embodiment of the present invention, in S1, the mass ratio of dopamine hydrochloride, Tris-HCl buffer solution, and ethanol aqueous solution is (2.5-3.5):(1.8-2.6):(180-220), for example, it can be (2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4 or 3.5):(1.8, 1.88, 1.96, 2.04, 2.12, 2.2, 2.28, 2.36, 2.44, 2.52 or 2.6):(180, 184, 188, 192, 196, 200, 204, 208, 212, 216 or 220), but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0027] In some alternative embodiments, the pH of the Tris-HCl buffer solution is 8.3-8.8, for example, it may be 8.3, 8.35, 8.4, 8.45, 8.5, 8.55, 8.6, 8.65, 8.7, 8.75 or 8.8, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0028] In some optional embodiments, the mass ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 3:1.

[0029] In some optional embodiments, the mass fraction of the ammonia water is 25-28 wt.%, for example, it can be 25 wt.%, 25.3 wt.%, 25.6 wt.%, 25.9 wt.%, 26.2 wt.%, 26.5 wt.%, 26.8 wt.%, 27.1 wt.%, 27.4 wt.%, 27.7 wt.%, or 28 wt.%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] In a preferred embodiment of the present invention, in S2, the mass ratio of copper tetrahydrate formate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol, and polydopamine microsphere powder is (8-12):(35-50):(15-25):(4-7):(3-6), for example, it can be (8, 8.4, 8.8, 9.2, 9.6, 10.0, 10.4, 10.8, 11.2, 11.6, or 12):(35, 36.5, 38, 39.5, 41, 42.5). 44, 45.5, 47, 48.5 or 50: (15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25): (4.0, 4.3, 4.6, 4.9, 5.2, 5.5, 5.8, 6.1, 6.4, 6.7 or 7.0): (3.0, 3.3, 3.6, 3.9, 4.2, 4.5, 4.8, 5.1, 5.4, 5.7 or 6.0), but not limited to the listed values, other unlisted values ​​within this range also apply.

[0031] In a preferred embodiment of the present invention, in step S3, the mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol is (20-28):(0.8-1.5):(0.3-0.8):(100-140), for example, (20, 20.8, 21.6, 22.4, 23.2, 24, 24.8, 25.6, 26.4, 27.2, or 28):(0.8, 0.87, 0.94, 1.01, 1). 08, 1.15, 1.22, 1.29, 1.36, 1.43 or 1.5: (0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 or 0.8): (100, 104, 108, 112, 116, 120, 124, 128, 132, 136 or 140), but not limited to the listed values; other unlisted values ​​within this range also apply.

[0032] In some optional embodiments, the D50 of the copper powder is 3-8 μm, for example, it can be 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm or 8 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0033] In some optional embodiments, the mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution is (2.5-4.5):(2.0-4.0):(20-35):(3-8):(8-15), for example, it can be (2.5, 2.7, 2.9, 3.1, 3.3, 3.5, 3.7, 3.9, 4.1, 4.3, or 4.5):(2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4). 3.6, 3.8 or 4.0: (20, 21.5, 23, 24.5, 26, 27.5, 29, 30.5, 32, 33.5 or 35): (3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8): (8, 8.7, 9.4, 10.1, 10.8, 11.5, 12.2, 12.9, 13.6, 14.3 or 15), but not limited to the listed values, other unlisted values ​​within this range also apply.

[0034] In some optional embodiments, the mass fraction of the sodium borohydride aqueous solution is 8-15 wt.%, for example, it can be 8%, 8.7%, 9.4%, 10.1%, 10.8%, 11.5%, 12.2%, 12.9%, 13.6%, 14.3% or 15%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] In some optional embodiments, the heat treatment is performed at a temperature of 150-180°C for a time of 20-40 minutes. For example, the temperature may be (150, 153, 156, 159, 162, 165, 168, 171, 174, 177 or 180)°C for a time of (20, 22, 24, 26, 28, 30, 32, 34, 36, 38 or 40) minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] As a preferred embodiment of the present invention, in S4, the mass ratio of N-imidazolium propyltrimethoxysilane, aqueous ethanol solution, and Cu@Sn-Bi core-shell microparticles is (1-2.5):(55-92):(20-28), for example, it can be (1, 1.15, 1.3, 1.45, 1.6, 1.75, 1.9, 2.05, 2.2, 2.35 or 2.5):(55, 58.7, 62.4, 66.1, 69.8, 73.5, 77.2, 80.9, 84.6, 88.3 or 92):(20, 20.8, 21.6, 22.4, 23.2, 24, 24.8, 25.6, 26.4, 27.2 or 28), but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0037] As a preferred technical solution of the present invention, in S5, the metal powder is one or more of copper, aluminum, nickel, silver, iron metal elemental powder and their alloy powder.

[0038] In some optional embodiments, the mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres to core-shell bridging microparticles is 100:(3-6):(30-60):(2-5):(5-10).

[0039] Furthermore, if easily oxidized elemental powders or alloy powders of aluminum or iron are used, the stirring process needs to be carried out in a negative pressure environment.

[0040] In some optional embodiments, the adhesive is one or more selected from polyolefins, fluoropolymers, acrylic resins, epoxy resins, phenolic resins, polyurethane resins, and polyimide resins.

[0041] Preferably, the adhesive is polyvinylidene fluoride or polyacrylic acid.

[0042] In some optional embodiments, the solvent is one or more of deionized water, ethyl acetate, acetone, N-methylpyrrolidone, and toluene.

[0043] In some optional embodiments, the planetary mixer is set with the following parameters: revolution 5-70 rpm, rotation 500-6000 rpm, mixing time 10-60 min, and mixing temperature 10-80℃. For example, the following values ​​could be used: revolution (5, 11.5, 18, 24.5, 31, 37.5, 44, 50.5, 57, 63.5 or 70) rpm, rotation (500, 1050, 1600, 2150, 2700, 3250, 3800, 4350, 4900, 5450 or 6000) rpm, stirring time (10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60) min, and stirring temperature (10, 17, 24, 31, 38, 45, 52, 59, 66, 73 or 80) °C. However, these values ​​are not limited to those listed, and other unlisted values ​​within this range are also applicable.

[0044] In some optional embodiments, the coating thickness is 30-300 μm, and the distance between the metal paste coating area and the electrode material area is not less than 1 mm.

[0045] In some optional embodiments, the curing temperature is 30-120°C and the time is 0.5-48h. For example, the temperature can be (30, 39, 48, 57, 66, 75, 84, 93, 102, 111 or 120)°C and the time can be (0.5, 5.25, 10.0, 14.75, 19.5, 24.25, 29.0, 33.75, 38.5, 43.25 or 48.0)h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Furthermore, the curing process needs to be carried out in a negative pressure environment.

[0047] In some optional embodiments, the parameters of the ultrasonic welding are: welding pressure 0.05-0.5 MPa, welding amplitude 5-200 μm, welding frequency 15 kHz-120 kHz, and welding time 0.05-5 s. For example, it could be: welding pressure of (0.05, 0.095, 0.14, 0.185, 0.23, 0.275, 0.32, 0.365, 0.41, 0.455, or 0.5) MPa, welding amplitude of (5, 24.5, 44, 63.5, 83, 102.5, 122, 141.5, 161, 180.5, or 200) μm, and welding frequency of (15, 25...). The frequency range is 0.5, 36, 46.5, 57, 67.5, 78, 88.5, 99, 109.5 or 120 kHz, and the welding time is (0.05, 0.545, 1.04, 1.535, 2.03, 2.525, 3.02, 3.515, 4.01, 4.505 or 5.0) s, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The welding strength is improved by the copper nanoparticle sintering network generated by the in-situ decomposition of copper formate, the Sn-Bi eutectic liquid phase wetting metallurgical bonding and the bridging effect of imidazole silane molecules; (2) The contact resistance is reduced, and the copper nanoparticle-carbon composite network generated in situ and the Sn-Bi metallurgical weld jointly construct a multi-level low-resistance conductive path; (3) The stepped temperature triggering characteristics of the triple bonding mechanism enable the welded parts to obtain sufficient bonding strength at a lower welding energy, thereby reducing the sensitivity to the accuracy of welding parameters, avoiding damage to the polymer substrate layer due to excessive welding energy, and broadening the welding process window. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the electrode welding area before welding when directly using traditional ultrasonic welding technology to weld composite current collectors.

[0050] Figure 2 This is a schematic diagram of the electrode welding area after welding when using traditional ultrasonic welding technology to weld composite current collectors.

[0051] Figure 3 This is a schematic diagram of the electrode tab area before welding, after the electrode tab of the composite current collector has undergone the process disclosed in this invention.

[0052] Figure 4 This is a schematic diagram of the electrode tab after welding, which is a composite current collector, after being processed by the process disclosed in this invention.

[0053] Figure 5The image shows the actual product of the electrode tab after welding in the electrode tab welding area, which is a composite current collector, after the process disclosed in this invention.

[0054] Figure 6 This is a TEM image of the core-shell bridging microparticles provided in Embodiment 1 of the present invention.

[0055] Explanation of reference numerals in the attached diagram: 0, welding area; 1, ultrasonic welding head;

[0056] 2. Composite current collector metal layer; 21. Damaged area of ​​composite current collector metal layer;

[0057] 3. Composite current collector polymer insulation layer; 31. Damaged area of ​​composite current collector polymer insulation layer;

[0058] 4. Metal slurry curing layer; 41. Metal particle molten layer; 42. Connection area between the metal particle molten layer and the composite current collector metal layer. Detailed Implementation

[0059] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0060] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0061] Reference Figure 1 and Figure 2 In welding zone 0, the high heat and vibration of the ultrasonic welding head 1 during ultrasonic welding are directly conducted into the composite current collector metal layer 2 and the composite current collector polymer insulation layer 3, causing damage to the composite current collector. This results in damaged areas 21 and 31 in the composite current collector metal layer and the composite current collector polymer insulation layer, ultimately leading to the detachment of the composite current collector metal layer 2 and the loss of strength in the composite current collector polymer insulation layer 3. Simultaneously, because the upper and lower composite current collector metal layers 2 are not conductive, current cannot be conducted vertically, causing an increase in the battery's internal resistance.

[0062] Example 1

[0063] This embodiment provides a battery composite current collector tab welding component and its preparation method, specifically including:

[0064] S1, dopamine hydrochloride, Tris-HCl buffer solution with pH 8.3, and ethanol aqueous solution are mixed. The mass ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 3:1. Ammonia solution with a mass fraction of 25 wt.% is added dropwise to adjust the pH to 8.3. The mixture is stirred and reacted for 8 hours. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain polydopamine microsphere powder. The mass ratio of dopamine hydrochloride, Tris-HCl buffer solution, and ethanol aqueous solution is 2.5:2.6:180.

[0065] S2, copper tetrahydrate, anhydrous ethanol, and deionized water are mixed and dispersed, and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution and dispersed evenly. The mixture is then distilled under reduced pressure and dried under vacuum to obtain copper tetrahydrate hybrid microspheres. The mass ratio of copper tetrahydrate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol, and polydopamine microsphere powder is 12:35:25:4:6.

[0066] S3, copper powder with a D50 of 3 μm, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol were mixed to obtain a suspension. The mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol was 20:1.5:0.3:140. Tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, and glacial acetic acid were mixed to obtain a metal salt solution. The metal salt solution was added dropwise to the suspension. The mixture was stirred at 85°C, and an 8 wt.% sodium borohydride aqueous solution was added dropwise. The reaction was continued for 90 min. The mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution was 2.5:4.0:20:8:8. After the reaction was completed, the mixture was filtered, washed, and dried. It was then subjected to thermal curing treatment under a nitrogen atmosphere at a temperature of 150°C for 40 min to obtain Cu@Sn-Bi core-shell microparticles.

[0067] S4, N-imidazolium propyltrimethoxysilane was added to an aqueous ethanol solution, and glacial acetic acid was added dropwise to adjust the pH to 4.0. The reaction was carried out for 2 hours to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles were added to the oligomer solution and stirred for 1 hour. The temperature was raised to 70°C and stirring was continued for 1 hour. The mass ratio of N-imidazolium propyltrimethoxysilane, aqueous ethanol solution and Cu@Sn-Bi core-shell microparticles was 2.5:55:28. The mixture was then filtered, washed and dried to obtain core-shell bridging microparticles.

[0068] S5, metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles are placed in a planetary mixer and stirred. The mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles is 100:3:30:2:5 to obtain a metal slurry. The metal powder is copper powder and iron powder in a mass ratio of 1:1. The binder is polyvinylidene fluoride, and the solvent is N-methylpyrrolidone. The planetary mixer is set with the following parameters: revolution at 70 rpm, rotation at 500 rpm, and stirring time at 60 min. n. Stirring temperature 10℃, the metal slurry is coated onto the electrode tab area of ​​the composite current collector to be welded, the coating thickness is 30μm, the distance between the metal slurry coating area and the electrode material area is not less than 1mm, stacking and curing to obtain a cured stack, the curing temperature is 120℃ and the time is 0.5h, the cured stack is ultrasonically welded, the ultrasonic welding parameters are: welding pressure 0.05MPa, welding amplitude 200μm, welding frequency 15kHz, welding time 5s, to obtain the battery composite current collector electrode tab welded part.

[0069] Figure 3 This is a schematic diagram of the electrode tab area before welding, after the composite current collector has undergone the process disclosed in this invention. (Refer to...) Figure 4 Due to the small particle size, high surface energy, and lower melting point of the metal particles, when the ultrasonic welding head 1 vibrates and heats the metal slurry solidification layer 4, the metal slurry first melts to form a molten metal particle layer 41. The melting of the metal particles absorbs some heat and acts as a physical barrier, reducing vibration and preventing damage to the composite current collector from high temperatures and vibration. The molten metal particle layer 41 contacts and conducts with the composite current collector metal layer 2, forming a connection area 42 between the molten metal particle layer and the composite current collector metal layer. Simultaneously, the molten metal particle layer 41 completes the connection between the upper and lower composite current collector metal layers 2 at the edge of the composite current collector, achieving full conductivity between the metal slurry and the composite current collector. A physical image of the battery composite current collector electrode tab welding component is shown below. Figure 5 As shown. Figure 6 This is a TEM image of the core-shell bridging microparticles provided in this embodiment.

[0070] Example 2

[0071] This embodiment provides a battery composite current collector tab welding component and its preparation method, specifically including:

[0072] S1, dopamine hydrochloride, Tris-HCl buffer solution with pH 8.8, and ethanol aqueous solution are mixed. The mass ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 3:1. Ammonia solution with a mass fraction of 28 wt.% is added dropwise to adjust the pH to 8.8. The mixture is stirred and reacted for 5 hours. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain polydopamine microsphere powder. The mass ratio of dopamine hydrochloride, Tris-HCl buffer solution, and ethanol aqueous solution is 3.5:1.8:220.

[0073] S2, copper tetrahydrate, anhydrous ethanol, and deionized water are mixed and dispersed, and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution and dispersed evenly. The mixture is then distilled under reduced pressure and dried under vacuum to obtain copper tetrahydrate hybrid microspheres. The mass ratio of copper tetrahydrate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol, and polydopamine microsphere powder is 8:50:15:7:3.

[0074] S3, copper powder with a D50 of 8 μm, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol were mixed to obtain a suspension. The mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol was 28:0.8:0.8:100. Tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, and glacial acetic acid were mixed to obtain a metal salt solution. The metal salt solution was added dropwise to the suspension. The mixture was stirred at 60°C, and a 15 wt.% sodium borohydride aqueous solution was added dropwise. The reaction was continued for 30 min. The mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution was 4.5:2.0:35:3:15. After the reaction was completed, the mixture was filtered, washed, and dried. It was then subjected to thermal curing treatment under a nitrogen atmosphere at a temperature of 180°C for 20 min to obtain Cu@Sn-Bi core-shell microparticles.

[0075] S4, N-imidazolium propyltrimethoxysilane was added to an aqueous ethanol solution, and glacial acetic acid was added dropwise to adjust the pH to 5.5. The reaction was carried out for 0.5 h to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles were added to the oligomer solution and stirred for 3 h. The temperature was raised to 50 °C and stirred for another 2 h. The mass ratio of N-imidazolium propyltrimethoxysilane, aqueous ethanol solution and Cu@Sn-Bi core-shell microparticles was 1:92:20. The mixture was then filtered, washed and dried to obtain core-shell bridging microparticles.

[0076] S5, metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles are placed in a planetary mixer and stirred. The mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles is 100:6:60:5:10 to obtain a metal slurry. The metal powder is silver powder and aluminum powder in a mass ratio of 1:1. The binder is polyimide resin, and the solvent is N-methylpyrrolidone. The planetary mixer is set with the following parameters: revolution at 5 rpm, rotation at 6000 rpm, and stirring time of 10 minutes. At a stirring temperature of 80°C, the metal slurry is coated onto the electrode tab area of ​​the composite current collector to be welded. The coating thickness is 100 μm, and the distance between the metal slurry coating area and the electrode material area is not less than 1 mm. The electrodes are stacked and cured to obtain a cured stack. The curing temperature is 30°C and the time is 48 h. The cured stack is then ultrasonically welded. The ultrasonic welding parameters are: welding pressure 0.5 MPa, welding amplitude 5 μm, welding frequency 120 kHz, and welding time 0.05 s, to obtain the battery composite current collector electrode tab welded part.

[0077] Example 3

[0078] This embodiment provides a battery composite current collector tab welding component and its preparation method, specifically including:

[0079] S1, dopamine hydrochloride, Tris-HCl buffer solution with pH 8.5, and ethanol aqueous solution are mixed. The mass ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 3:1. Ammonia solution with a mass fraction of 26 wt.% is added dropwise to adjust the pH to 8.5. The mixture is stirred and reacted for 6 hours. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain polydopamine microsphere powder. The mass ratio of dopamine hydrochloride, Tris-HCl buffer solution, and ethanol aqueous solution is 3.0:2.2:200.

[0080] S2, copper formate tetrahydrate, anhydrous ethanol, and deionized water are mixed and dispersed, and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution and dispersed evenly. The mixture is then distilled under reduced pressure and dried under vacuum to obtain copper formate hybrid microspheres. The mass ratio of copper formate tetrahydrate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol, and polydopamine microsphere powder is 10:42:20:5.5:4.5.

[0081] S3, copper powder with a D50 of 5 μm, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol were mixed to obtain a suspension. The mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol was 24:1.2:0.5:120. Tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, and glacial acetic acid were mixed to obtain a metal salt solution. The metal salt solution was added dropwise to the suspension. The mixture was stirred at 75°C, and a 12 wt.% sodium borohydride aqueous solution was added dropwise. The reaction was continued for 60 min. The mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution was 3.5:3.0:28:5:12. After the reaction was completed, the mixture was filtered, washed, and dried. It was then subjected to thermal curing treatment under a nitrogen atmosphere at a temperature of 165°C for 30 min to obtain Cu@Sn-Bi core-shell microparticles.

[0082] S4, N-imidazolium propyltrimethoxysilane was added to an aqueous ethanol solution, and glacial acetic acid was added dropwise to adjust the pH to 4.8. The reaction was carried out for 1.2 h to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles were added to the oligomer solution and stirred for 2 h. The temperature was raised to 60 °C and stirring was continued for 1.5 h. The mass ratio of N-imidazolium propyltrimethoxysilane, aqueous ethanol solution and Cu@Sn-Bi core-shell microparticles was 1.8:75:24. The mixture was then filtered, washed and dried to obtain core-shell bridging microparticles.

[0083] S5, metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles are placed in a planetary mixer and stirred. The mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles is 100:4:40:3:6 to obtain a metal slurry. The metal powder is nickel powder, the binder is epoxy resin, and the solvent is acetone. The planetary mixer is set with the following parameters: revolution at 30 rpm, rotation at 3000 rpm, stirring time at 35 min, and stirring temperature at 45°C. At ℃, the metal slurry is coated onto the electrode tab area of ​​the composite current collector to be welded. The coating thickness is 300μm, and the distance between the metal slurry coating area and the electrode material area is not less than 1mm. The electrodes are stacked and cured to obtain a cured stack. The curing temperature is 60℃ and the time is 24h. The cured stack is ultrasonically welded. The ultrasonic welding parameters are: welding pressure 0.3MPa, welding amplitude 100μm, welding frequency 60kHz, and welding time 2s to obtain the battery composite current collector electrode tab welded part.

[0084] Example 4

[0085] This embodiment provides a battery composite current collector tab welding component and its preparation method, specifically including:

[0086] S1, dopamine hydrochloride, Tris-HCl buffer solution with pH 8.6, and ethanol aqueous solution are mixed. The mass ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 3:1. Ammonia solution with a mass fraction of 27 wt.% is added dropwise to adjust the pH to 8.6. The mixture is stirred and reacted for 7 hours. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain polydopamine microsphere powder. The mass ratio of dopamine hydrochloride, Tris-HCl buffer solution, and ethanol aqueous solution is 2.8:2.4:190.

[0087] S2, copper formate tetrahydrate, anhydrous ethanol, and deionized water are mixed and dispersed, and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution and dispersed evenly. The mixture is then distilled under reduced pressure and dried under vacuum to obtain copper formate hybrid microspheres. The mass ratio of copper formate tetrahydrate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol, and polydopamine microsphere powder is 9:45:18:6.5:5.5.

[0088] S3, copper powder with a D50 of 6 μm, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol were mixed to obtain a suspension. The mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid, and ethylene glycol was 26:1.0:0.6:110. Tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, and glacial acetic acid were mixed to obtain a metal salt solution. The metal salt solution was added dropwise to the suspension. The mixture was stirred at 70 °C, and a 10 wt.% sodium borohydride aqueous solution was added dropwise. The reaction was continued for 75 min. The mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution was 4.0:2.5:25:6:10. After the reaction was completed, the mixture was filtered, washed, and dried. It was then subjected to thermal curing treatment under a nitrogen atmosphere at a temperature of 175 °C for 25 min to obtain Cu@Sn-Bi core-shell microparticles.

[0089] S4, N-imidazolium propyltrimethoxysilane was added to an aqueous ethanol solution, and glacial acetic acid was added dropwise to adjust the pH to 5.0. The reaction was carried out for 1.5 h to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles were added to the oligomer solution and stirred for 2.5 h. The temperature was raised to 65 °C and stirring was continued for 1.2 h. The mass ratio of N-imidazolium propyltrimethoxysilane, aqueous ethanol solution and Cu@Sn-Bi core-shell microparticles was 2.2:65:22. The mixture was then filtered, washed and dried to obtain core-shell bridging microparticles.

[0090] S5, metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles are placed in a planetary mixer and stirred. The mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres, and core-shell bridging microparticles is 100:5:50:4:8 to obtain a metal slurry. The metal powder is aluminum powder, the binder is polyacrylic acid, and the solvent is deionized water. The planetary mixer is set with the following parameters: revolution at 50 rpm, rotation at 4500 rpm, stirring time at 25 min, and stirring temperature at 60°C. At ℃, the metal slurry is coated onto the electrode tab area of ​​the composite current collector to be welded. The coating thickness is 200μm, and the distance between the metal slurry coating area and the electrode material area is not less than 1mm. The electrodes are stacked and cured to obtain a cured stack. The curing temperature is 80℃ and the time is 12h. The cured stack is ultrasonically welded. The ultrasonic welding parameters are: welding pressure 0.2MPa, welding amplitude 150μm, welding frequency 40kHz, and welding time 3.5s to obtain the battery composite current collector electrode tab welded part.

[0091] Comparative Example 1

[0092] This comparative example provides a battery composite current collector electrode welding component and its preparation method. The difference between this and Example 1 is that copper formate hybrid microspheres are not added in S5, while other process parameters and operating conditions are exactly the same as in Example 1.

[0093] Comparative Example 2

[0094] This comparative example provides a battery composite current collector electrode welding component and its preparation method. The difference between this and Example 1 is that no core-shell bridging microparticles are added in S5, while other process parameters and operating conditions are exactly the same as in Example 1.

[0095] Comparative Example 3

[0096] This comparative example provides a battery composite current collector electrode welding component and its preparation method. The difference between this and Example 1 is that S4 is omitted, and Cu@Sn-Bi core-shell microparticles obtained in S3 are directly used in S5. Other process parameters and operating conditions are exactly the same as in Example 1.

[0097] Comparative Example 4

[0098] This comparative example provides a battery composite current collector tab welded component and its preparation method. The difference between this and Example 1 is that the composite current collector tabs are directly stacked and welded using the same ultrasonic welding parameters as in Example 1.

[0099] Performance testing:

[0100] Peel strength test: The welded parts were subjected to T-shaped peel test using a universal tensile testing machine. Tensile peeling was performed along the welded joint area at a tensile rate of 50 mm / min. The maximum peel force (N) was recorded. The average value of 5 samples in each group was taken.

[0101] Contact resistance test: The contact resistance (mΩ) of the welded area was measured using the four-probe method. Three points were measured for each sample and the average value was taken.

[0102] High temperature and high humidity reliability test: After the welded parts are stored at 85℃ / 85%RH for 500h, the peel strength and contact resistance are remeasured, and the peel strength retention rate and contact resistance growth rate are calculated.

[0103] Table 1 shows the test results of the battery composite current collector tab welded components of Examples 1-4 and Comparative Examples 1-4.

[0104] Table 1 Test results of composite current collector tab welded components of Examples 1-4 and Comparative Examples 1-4

[0105]

[0106] As shown in Table 1, compared to Example 1, Comparative Example 1 showed a decrease in peel strength, an increase in contact resistance, a decrease in peel strength retention rate, and an increase in the contact resistance growth rate; Comparative Example 2 showed a decrease in peel strength, an increase in contact resistance, a decrease in peel strength retention rate, and an increase in the contact resistance growth rate; Comparative Example 3 showed a decrease in peel strength, an increase in contact resistance, a decrease in peel strength retention rate, and an increase in the contact resistance growth rate; and Comparative Example 4 showed a decrease in peel strength, an increase in contact resistance, a decrease in peel strength retention rate, and an increase in the contact resistance growth rate.

[0107] This is because, in Comparative Example 1, the lack of copper formate hybrid microspheres prevented the welding interface from decomposing in situ to generate highly active copper nanoparticles in the ultrasonic local thermal field. This resulted in the loss of the ability to form a dense metal interconnect network through sintering of nano-copper, reducing the metallurgical bonding area between the interfacial metals. Furthermore, the carbonization of the PDA microspheres only formed a carbon skeleton without copper nanoparticle filling, leading to incomplete conductive pathways. In Comparative Example 2, the lack of Cu@Sn-Bi core-shell bridging microparticles prevented the eutectic melting process of the low-melting-point Sn-Bi alloy shell at the welding interface. This prevented the generation of liquid metal wetting to fill the microscopic gaps at the interface, resulting in the loss of the transient liquid-phase diffusion welding mechanism. The weld bond degenerated from a continuous metallurgical weld to a solid-state mechanical interlocking. In Comparative Example 3, the untreated Cu@Sn-Bi microparticles retained the Sn-Bi eutectic melting welding capability; however, the lack of coordination bridging between the imidazole groups and the copper surface resulted in a lack of molecular-level chemical bonding between the particles and the current collector interface, leading to weak interfacial bonding. The absence of imidazole corrosion inhibition protection also made the microparticle surface prone to oxidation during storage and curing. In Comparative Example 4, when directly welded, the extremely thin copper layers rely solely on solid-state plastic deformation generated by ultrasonic vibration to achieve limited metallurgical bonding. The effective bonding area is small, there is no filler metal or conductive filler, and a large number of air gaps remain between the layers, resulting in increased contact resistance.

[0108] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A battery composite current collector tab welding component, characterized in that, It includes a composite current collector tab and a welded connection layer. The welded connection layer is disposed on the weldable part of the composite current collector tab and is formed by curing a metal slurry and ultrasonic welding. The metal slurry includes metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles.

2. A method for preparing a battery composite current collector tab welded as described in claim 1, characterized in that, The preparation method includes: S1, dopamine hydrochloride, Tris-HCl buffer and ethanol aqueous solution are mixed, pH is adjusted and then reacted to obtain polydopamine microsphere powder; S2, copper formate tetrahydrate, anhydrous ethanol and deionized water are mixed and then 2-amino-2-methyl-1-propanol is added to obtain a composite precursor solution. Polydopamine microsphere powder is added to the composite precursor solution to obtain copper formate hybrid microspheres. S3, copper powder, polyvinylpyrrolidone, ascorbic acid and ethylene glycol are mixed to obtain a suspension, tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol and glacial acetic acid are mixed to obtain a metal salt solution, the metal salt solution is added dropwise to the suspension and sodium borohydride aqueous solution is added dropwise to react and perform heat aging treatment to obtain Cu@Sn-Bi core-shell microparticles; S4, N-imidazolium propyltrimethoxysilane is added to an aqueous ethanol solution, the pH is adjusted and the reaction is carried out to obtain an imidazolium silane oligomer solution. Cu@Sn-Bi core-shell microparticles are added to the imidazolium silane oligomer solution and stirred to obtain core-shell bridging microparticles. S5, metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles are placed in a planetary mixer and stirred to obtain a metal slurry. The metal slurry is coated on the electrode tab part of the composite current collector to be welded, stacked and cured to obtain a cured stack. The cured stack is ultrasonically welded to obtain a battery composite current collector electrode tab welded part.

3. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S1: The mass ratio of dopamine hydrochloride, Tris-HCl buffer solution and ethanol aqueous solution is (2.5-3.5):(1.8-2.6):(180-220).

4. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S2: The mass ratio of copper tetrahydrate, anhydrous ethanol, deionized water, 2-amino-2-methyl-1-propanol and polydopamine microsphere powder is (8-12):(35-50):(15-25):(4-7):(3-6).

5. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S3: The mass ratio of copper powder, polyvinylpyrrolidone, ascorbic acid and ethylene glycol is (20-28):(0.8-1.5):(0.3-0.8):(100-140).

6. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S3: The mass ratio of tin dichloride dihydrate, bismuth nitrate pentahydrate, ethylene glycol, glacial acetic acid, and sodium borohydride aqueous solution is (2.5-4.5):(2.0-4.0):(20-35):(3-8):(8-15); The heat curing treatment is performed at a temperature of 150-180℃ for 20-40 minutes.

7. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S4: The mass ratio of the N-imidazolium propyltrimethoxysilane, the aqueous ethanol solution, and the Cu@Sn-Bi core-shell microparticles is (1-2.5):(55-92):(20-28).

8. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S5: The mass ratio of the metal powder, binder, solvent, copper formate hybrid microspheres and core-shell bridging microparticles is 100:(3-6):(30-60):(2-5):(5-10). The metal powder is one or more of the following: copper, aluminum, nickel, silver, iron elemental powder and their alloy powder; The adhesive is one or more of the following: polyolefin, fluoropolymer, acrylic resin, epoxy resin, phenolic resin, polyurethane resin, and polyimide resin; The solvent is one or more of deionized water, ethyl acetate, acetone, N-methylpyrrolidone, and toluene.

9. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S5: The coating thickness is 30-300μm, and the distance between the metal paste coating area and the electrode material area is not less than 1mm; The curing temperature is 30-120℃, and the time is 0.5-48h.

10. The method for preparing a battery composite current collector electrode welding component according to claim 2, characterized in that, In S5: The parameters for ultrasonic welding are: welding pressure 0.05-0.5MPa, welding amplitude 5-200μm, welding frequency 15kHz-120kHz, and welding time 0.05-5s.

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