Anti-corrosion nickel-coated copper strip, method for manufacturing the same and use thereof

Abstract

The present application relates to the technical field of battery element, especially relates to a kind of anticorrosive nickel-coated copper strip and its preparation method and application.Nickel-coated copper strip includes nickel layer, copper layer, nickel layer from top to bottom, wherein copper layer is sealed by nickel around, and mutual penetration exists between copper atom and nickel atom;The nickel-coated copper strip is made by spraying liquid copper to nickel layer, and then co-rolling with another nickel layer;At least one of graphene and carbon nanotube is dispersed in copper layer;The content of graphene or carbon nanotube in copper pipe is 1% to 10%.The anticorrosive nickel-coated copper strip provided by the present application has the advantages of effectively preventing copper corrosion by wrapping copper inside under the condition of protecting the high bonding strength between copper and nickel;Carbon nanotube and / or graphene are first ground with copper powder, then heated and stirred to disperse in copper liquid, which greatly enhances the mechanical strength and electrical conductivity of the composite strip, and is mainly used for making battery tabs.

Description

Technical Field

[0001] This invention relates to the field of battery element technology, and in particular to a corrosion-resistant nickel-clad copper strip, its preparation method, and its application. Background Technology

[0002] Nickel-copper composite strips are widely used in batteries, electrical components, and other fields. The tabs are conductors drawn from the battery electrodes. Traditional tabs use nickel strips, which have poor conductivity. Improved tabs use nickel-plated copper strips, where the nickel layer is responsible for welding to the battery electrodes, while the copper layer provides good conductivity. Although this component ensures conductivity and welding performance, because the copper is not completely covered by the nickel layer on both sides, one side of the copper is exposed and in direct contact with the electrolyte. This causes the electrolyte to corrode along the copper layer, and if the bonding strength between the copper and nickel is insufficient, the conductivity of the strip will decrease significantly.

[0003] For example, Chinese patent CN202011312525.0 discloses a method and apparatus for preparing high-performance strip by multi-nozzle deposition rolling. The alloy is completely melted, atomized, and sprayed onto the rolls to roll out high-strength alloy strip. Since the entire alloy is melted from the beginning, it is impossible to maintain the solid shape of copper inside and nickel outside, and the corrosion resistance of nickel-coated copper cannot be guaranteed. Summary of the Invention

[0004] In view of the lack of corrosion-resistant nickel-clad copper strip and its preparation process in the existing technology, the present invention provides a corrosion-resistant nickel-clad copper strip, which has the advantage of effectively preventing copper corrosion by encapsulating the copper with nickel while protecting the high bonding strength between copper and nickel. The present invention also provides a method for preparing the corrosion-resistant nickel-clad copper strip, and the prepared nickel-clad copper strip has the advantage of effectively preventing copper corrosion by encapsulating the copper with nickel while protecting the high bonding strength between copper and nickel. The present invention also provides battery tabs made of nickel-clad copper strip made by the corrosion-resistant nickel-clad copper strip or the method for preparing the corrosion-resistant nickel-clad copper strip, which have good conductivity, are not easily corroded by copper, and have a long service life.

[0005] This invention is achieved through the following technical solution:

[0006] A corrosion-resistant nickel-clad copper strip, comprising, from top to bottom, a nickel layer, a copper layer, and another nickel layer, wherein the copper layer is sealed with nickel on all sides, and there is interpenetration between copper atoms and nickel atoms; the nickel-clad copper strip is formed by spraying liquid copper onto the nickel layer and then co-rolling it with another nickel layer.

[0007] Preferably, the copper layer contains at least one of graphene and carbon nanotubes.

[0008] Preferably, the graphene or carbon nanotubes contain 1% to 10% copper.

[0009] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0010] 1) Place liquid copper into the jet deposition equipment and place the ends of the two nickel strips between the two rolls;

[0011] 2) Liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips, while initial rolling is performed to form a composite.

[0012] 3) The nickel-copper composite strip from step 2) is further rolled, annealed, and repeated several times, and then cleaned.

[0013] Preferably, the liquid copper in step 1) is obtained by melting, and the melting temperature is greater than the melting point of copper and less than the boiling point of copper.

[0014] Preferably, the distance between the rolling rollers in step 1) is 300 μm to 1500 μm; the liquid copper in step 1) is obtained by the following steps:

[0015] Step (1) Under a protective atmosphere, copper powder, multi-walled carbon nanotubes and / or graphene = 7~10:1 are mechanically ground and mixed to obtain mixture I, and then N-methylpyrrolidone (NMP) is added and mechanically stirred to obtain mixture II;

[0016] Step (2) Heat the mixture II prepared in step (1) to melt the copper powder and stir to obtain mixture III;

[0017] In step (3), solid copper is heated to melt, and mixture III from step (2) is added and stirred to completely disperse carbon nanotubes and / or graphene, thus obtaining carbon nanotubes and / or graphene-liquid copper.

[0018] Preferably, in step (1), the mixing mass ratio of copper powder, multi-walled carbon nanotubes and / or graphene is 7-10:1, the mixing mass ratio of N-methylpyrrolidone solution to the mixture I is 2.8-3.5 ml:1 g; the size range of the multi-walled carbon nanotubes and / or graphite is 3-10 nm inner diameter, 8-30 nm outer diameter, and 0.5-50 μm length; the mechanical stirring time is 10-30 min, and the protective atmosphere is nitrogen or argon.

[0019] Preferably, the heating temperature of mixture II in step (2) is the copper melting point +20 to 50°C, and the stirring time is 15 to 45 min; the heating temperature of the solid copper in step (3) is the copper melting point +20 to 50°C, and the stirring time is 15 to 45 min.

[0020] Preferably, in step 1), the distance between the rollers is 300μm to 1500μm; the rollers are kept at a constant temperature of 25℃.

[0021] Preferably, in step 2), the spray width is 0-50 mm and the spray flow rate is 0-5 g·s. -1 The initial rolling speed is 0.2–2 cm·s. -1 The rolling mill is kept at a constant temperature of 25°C; when the liquid copper in step 2) is deposited onto the nickel strip, 30%-70% is in a liquid state; the liquid copper particle size distribution is between 20μm and 200μm, and the proportion of particles larger than 200μm is >50%; the liquid copper is atomized by gas atomization or centrifugal atomization; the length and width of the copper jet deposition are smaller than the length and width of the nickel strip, respectively.

[0022] Preferably, in step 3), the rolling process is maintained at a constant temperature of 25°C, and the roll linear speed is 0.5–3 cm·s. -1 The rolling process is 1-20 times, and the deformation of the nickel-clad copper strip is less than 40% each time; the annealing temperature is 400-700℃, and the holding time is 2-4 hours.

[0023] A battery tab made of nickel-clad copper strip or nickel-clad copper strip prepared by the above preparation method.

[0024] The beneficial effects of this invention are:

[0025] (1) Heat copper to molten state and spray it onto nickel strip at a certain spraying speed. Then roll it with another nickel strip to form a composite strip. The nickel completely encapsulates the copper to prevent the copper from being corroded by the outside world and extend the service life of the strip.

[0026] (2) Copper is rolled and bonded with nickel layer under high heat. Copper atoms are fluid and can easily fill the gaps between them and nickel. The high heat of copper also increases the temperature of nearby nickel atoms, which effectively increases the atomic diffusion between the copper and nickel interfaces and increases the bonding strength between the copper and nickel interfaces. The high bonding strength and fewer gaps are also accompanied by an increase in electrical conductivity.

[0027] (3) Carbon nanotubes and / or graphene are first ground with copper powder, and then heated and stirred to disperse in copper liquid, which greatly enhances the mechanical strength and electrical conductivity of the composite strip.

[0028] (4) N-methylpyrrolidone is added as a dispersant to make carbon nanotubes and / or graphene uniformly dispersed in copper liquid. After the dispersion of graphene and carbon nanotubes is completed, they reach the boiling point and are vaporized and discharged during the further stirring of high temperature copper liquid. Due to the addition of dispersant and continuous stirring, carbon nanotubes and graphene have good dispersibility, thereby uniformly enhancing the mechanical strength of the strip.

[0029] (5) The preparation process is simplified and the additives are simple, which is conducive to large-scale industrial promotion. Attached Figure Description

[0030] Figure 1 This refers to the liquid copper spray rolling process.

[0031] Figure 2 This is a schematic diagram of the cross-sectional structure of nickel-clad copper strip. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0035] Step 1) Heat the copper until it melts into liquid copper at a temperature of 1420K;

[0036] Step 2) Place liquid copper into the jet deposition equipment, place the ends of the two nickel strips between the two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide;

[0037] Step 3) The liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0038] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip 8 times to obtain a composite strip. The rolling speed is 2 cm·s. -1 The thickness of the composite strip is reduced by 15-20% each time it is rolled, and it is annealed 8 times. After cleaning, the annealing temperature is 500℃ and the holding time is 2h to obtain nickel-clad copper composite strip.

[0039] Example 2

[0040] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0041] Step 1) Preparation of liquid copper with dispersed multi-walled carbon nanotubes: Under a protective atmosphere, copper powder and multi-walled carbon nanotubes in a ratio of 8:1 were mechanically ground and mixed to obtain mixture I. Then, N-methylpyrrolidone (NMP) was added, and the ratio of mixture I to NMP was 1 g to 2.8 ml. The mixture was mechanically stirred for 15 min to obtain mixture II. The mixture II prepared above was heated until the copper powder melted, and stirred for 15 min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper was heated until it melted, and mixture III was added at a ratio of 2% of the total copper content to carbon nanotubes. The mixture was stirred for 20 min to completely disperse the carbon nanotubes to obtain carbon nanotube-liquid copper.

[0042] Step 2) Place the carbon nanotube-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, keep the rolls at a constant temperature of 25°C, the initial roll distance is 500 μm, the initial nickel strip thickness is 100 μm and the width is 40 μm.

[0043] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, it undergoes preliminary rolling into a composite strip at a rolling speed of 1 cm·s. -1 .

[0044] Step 4) Roll the nickel strip with the copper deposited side facing another nickel strip 8 times to obtain a composite strip. The thickness of the composite strip is reduced by 15-20% each time it is rolled. After each rolling, the strip is pulled back and cleaned. The annealing temperature is 500℃ and the holding time is 2h to obtain a nickel-coated copper composite strip.

[0045] Example 3

[0046] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0047] Step 1) Preparation of liquid copper with dispersed multi-walled carbon nanotubes: Under a protective atmosphere, copper powder and multi-walled carbon nanotubes in a ratio of 9:1 were mechanically ground and mixed to obtain mixture I. Then, N-methylpyrrolidone was added, and the mixture ratio of mixture I to NMP was 1 g: 3.2 ml. The mixture was mechanically stirred for 20 min to obtain mixture II. The mixture II prepared above was heated until the copper powder melted, and stirred for 20 min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper was heated until it melted, and mixture III was added at a final carbon nanotube ratio of 5% of the total copper. The mixture was stirred for 20 min to completely disperse the carbon nanotubes to obtain carbon nanotube-liquid copper.

[0048] Step 2) Place the carbon nanotube-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide.

[0049] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0050] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 450℃ for 2.5 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0051] Example 4

[0052] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0053] Step 1) Preparation of liquid copper with dispersed multi-walled carbon nanotubes: Under a protective atmosphere, copper powder and multi-walled carbon nanotubes in a ratio of 9:1 were mechanically ground and mixed to obtain mixture I. Then, N-methylpyrrolidone was added, and the mixture ratio of mixture I to NMP was 1 g: 3.2 ml. The mixture was mechanically stirred for 20 min to obtain mixture II. The mixture II prepared above was heated until the copper powder melted, and stirred for 20 min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper was heated until it melted, and mixture III was added at a final carbon nanotube ratio of 5% of the total copper. The mixture was stirred for 20 min to completely disperse the carbon nanotubes to obtain carbon nanotube-liquid copper.

[0054] Step 2) Place the carbon nanotube-liquid copper obtained in Step 1) into a spray deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 650 μm, and the initial nickel strip size is 200 μm thick and 35 mm wide.

[0055] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 30 mm and the spray flow rate is 0.855 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 0.8 cm·s. -1 .

[0056] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 20-25% with each rolling. After each rolling, it is annealed at 500℃ for 2.5 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0057] Example 5

[0058] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0059] Step 1) Preparation of liquid copper with graphene dispersion: Under a protective atmosphere, copper powder and graphene are mechanically ground and mixed in a ratio of 8:1 to obtain mixture I. Then, N-methylpyrrolidone is added, and the ratio of mixture I to NMP is 1g:2.8ml. The mixture is mechanically stirred for 15min to obtain mixture II. The mixture II prepared above is heated until the copper powder melts, and stirred for 15min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper is heated until it melts, and mixture III is added at a final graphene ratio of 2% of the total copper. The mixture is stirred for 20min to completely disperse the graphene, thus obtaining carbon nanotube-liquid copper.

[0060] Step 2) Place the graphene-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide.

[0061] Step 3) The graphene-liquid copper was atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width was 35 mm and the spray flow rate was 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0062] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 500℃ for 2 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0063] Example 6

[0064] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0065] Step 1) Preparation of liquid copper with graphene dispersion: Under a protective atmosphere, copper powder and graphene are mechanically ground and mixed in a ratio of 9:1 to obtain mixture I. Then, N-methylpyrrolidone is added, and the ratio of mixture I to NMP is 1g:3.2ml. The mixture is mechanically stirred for 20min to obtain mixture II. The mixture II prepared above is heated until the copper powder melts, and stirred for 20min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper is heated until it melts, and mixture III is added at a final graphene ratio of 5% of the total copper content. The mixture is stirred for 20min to completely disperse the graphene, thus obtaining graphene-liquid copper.

[0066] Step 2) Place the graphene-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide.

[0067] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0068] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 450℃ for 2.5 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0069] Example 7

[0070] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0071] Step 1) Preparation of liquid copper with graphene dispersion: Under a protective atmosphere, copper powder and graphene are mechanically ground and mixed in a ratio of 9:1 to obtain mixture I. Then, N-methylpyrrolidone is added, and the ratio of mixture I to NMP is 1g:3.2ml. The mixture is mechanically stirred for 20min to obtain mixture II. The mixture II prepared above is heated until the copper powder melts, and stirred for 20min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper is heated until it melts, and mixture III is added at a final graphene ratio of 5% of the total copper content. The mixture is stirred for 20min to completely disperse the graphene, thus obtaining graphene-liquid copper.

[0072] Step 2) Place the graphene-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 650 μm, and the initial nickel strip size is 200 μm thick and 35 mm wide.

[0073] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 30 mm and the spray flow rate is 1.29 g·s. -1 Simultaneously, it undergoes preliminary rolling into a composite strip at a rolling speed of 1.2 cm·s. -1 .

[0074] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 20-25% with each rolling. After each rolling, it is annealed at 450℃ for 2.5 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0075] Example 8

[0076] A method for preparing corrosion-resistant nickel-clad copper strip includes the following steps:

[0077] Step 1) Preparation of liquid copper dispersed with graphene-carbon nanotubes: Under a protective atmosphere, copper powder, graphene, and carbon nanotubes in a ratio of 9:0.5:0.5 were mechanically ground and mixed to obtain mixture I. Then, N-methylpyrrolidone was added, and the mixture ratio of mixture I to NMP was 1g:3.2ml. The mixture was mechanically stirred for 20min to obtain mixture II. The mixture II prepared above was heated until the copper powder melted, and stirred for 20min with a special electromagnetic stirrer for metal furnaces to obtain mixture III. Solid copper was heated until it melted, and mixture III was added according to the final ratio of graphene and multi-walled carbon nanotubes each accounting for 2.5% of the total copper. The mixture was stirred for 20min to completely disperse the graphene and multi-walled carbon nanotubes to obtain graphene-multi-walled carbon nanotube-liquid copper.

[0078] Step 2) Place the graphene-multi-walled carbon nanotube liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide.

[0079] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0080] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 450℃ for 2.5 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0081] Comparative Example 1

[0082] A nickel-clad copper strip includes the following steps:

[0083] Step 1) Heat solid copper to molten state and then place it in a spray deposition apparatus. Place the end of a nickel strip between two rolls and keep the rolls at a constant temperature of 25°C. The initial roll distance is 700 μm and the initial nickel strip size is 400 μm thick and 40 mm wide.

[0084] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 40 mm and the spray flow rate is 1.43 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0085] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 500℃ for 2 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0086] Comparative Example 2

[0087] A nickel-clad copper strip includes the following steps:

[0088] Step 1) Heat solid copper to melt, and add carbon nanotubes at a final carbon nanotube ratio of 5% of the total copper to obtain carbon nanotube-liquid copper.

[0089] Step 2) Place the carbon nanotube-liquid copper obtained in Step 1) into a jet deposition apparatus, place the ends of the two nickel strips between two rolls, and keep the rolls at a constant temperature of 25°C; the initial roll distance is 500 μm, and the initial nickel strip size is 100 μm thick and 40 mm wide.

[0090] Step 3) Carbon nanotube-liquid copper is atomized into droplets and then sprayed onto one side of one of the nickel strips. The spray width is 35 mm and the spray flow rate is 1.25 g·s. -1 Simultaneously, the strip is initially rolled into a composite strip at a rolling speed of 1 cm·s. -1 .

[0091] Step 4) Roll the nickel strip with the copper-deposited side facing another nickel strip. The rolling speed is 2 cm / s. -1 The composite strip is obtained by rolling 5-8 times. The thickness of the composite strip is reduced by 15-20% with each rolling. After each rolling, it is annealed at 500℃ for 2 hours. Finally, it is cleaned to obtain nickel-clad copper composite strip.

[0092] Detection method:

[0093] The electrical conductivity was measured by a DC resistance meter, with resistance R. The sample length L = 100 cm and cross-sectional area S = 0.02 × 0.4 = 0.008 cm². The resistivity ρ = RS / L and the electrical conductivity G = 1 / ρ were calculated. The tensile strength and elongation were tested by a universal testing machine. The sample was then longitudinally sliced ​​into thin sections, and the cross-section was analyzed by backscattering analysis using SEM. The data are shown in Table 1 below.

[0094] Table 1. Data on the shape, electrical conductivity, tensile strength, and elongation of nickel-clad copper composite strips in each embodiment and comparative example.

[0095]

[0096]

[0097] As shown in Table 1, Example 1, without the addition of carbon nanotubes or graphene, exhibited higher electrical conductivity than Comparative Examples 1 and 2, but was the lowest among all examples, indicating that the addition of carbon nanotubes or graphene significantly improves the electrical conductivity of the tape. Example 3, with more carbon nanotubes than Example 2, showed increased electrical conductivity and tensile strength, while Example 4, with a thicker nickel layer, showed decreased electrical conductivity and tensile strength compared to Example 3. Example 6, with more graphene than Example 5, showed increased electrical conductivity and tensile strength, while Example 7, with a thicker nickel layer, showed decreased electrical conductivity and tensile strength. The degree of dispersion was reduced; the conductivity and tensile strength of Example 8 were higher than those of Examples 3 and 6, indicating that the effect of adding graphene and carbon nanotubes in combination was higher than that of adding them alone; while the conductivity and tensile strength of Comparative Example 1, which did not completely cover copper with nickel, were lower than those of the other examples; even with the addition of carbon nanotubes, the conductivity and tensile strength of Comparative Example 2, which was not stirred, decreased significantly, indicating that dispersibility has a great influence on the technical effect. The best technical effect of Example 8 may be due to the mutual doping of graphene and carbon nanotubes, which further improved the dispersibility.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a corrosion-resistant nickel-clad copper strip, characterized in that, Includes the following steps: 1) Place liquid copper into the jet deposition equipment and place the ends of the two nickel strips between the two rolls; 2) Liquid copper is atomized into droplets and sprayed onto one side of one of the nickel strips, while preliminary rolling is performed to obtain a preliminary composite strip; 3) The preliminary composite strip from step 2) is further rolled, annealed and repeated several times, and then cleaned to obtain nickel-clad copper composite strip; the distance between the rolling rollers in step 1) is 300µm~1500µm; The liquid copper mentioned in step 1) is obtained by the following steps: Step (1) Copper powder, multi-walled carbon nanotubes and / or graphene are mechanically ground and mixed under a protective atmosphere to obtain mixture I, and then N-methylpyrrolidone is added and mechanically stirred to obtain mixture II; Step (2) Heat mixture II prepared in step (1) until the copper powder melts, and stir to obtain mixture III; Step (3) Heat solid copper to melt, add mixture III from step (2), and stir to completely disperse carbon nanotubes and / or graphene to obtain carbon nanotubes and / or graphene-liquid copper; The nickel-clad copper strip comprises, from top to bottom, a nickel layer, a copper layer, and another nickel layer, wherein the copper layer is sealed with nickel on all sides, and copper atoms and nickel atoms permeate each other.

2. The corrosion-resistant nickel-clad copper strip according to claim 1, characterized in that, In step (1), the mass ratio of copper powder, multi-walled carbon nanotubes and / or graphene is 7~10:1, the mixing ratio of N-methylpyrrolidone to the mixture I is 2.8-3.5ml:1g, and the mechanical stirring time is 10~30min.

3. The corrosion-resistant nickel-clad copper strip according to claim 1, characterized in that, The multi-walled carbon nanotubes and / or graphite in step (1) have an inner diameter of 3-10 nm, an outer diameter of 8-30 nm, and a length of 0.5-50 μm; the mechanical stirring time is 10-30 min; and the protective atmosphere is nitrogen or argon.

4. The corrosion-resistant nickel-clad copper strip according to claim 1, characterized in that, The heating temperature of mixture II in step (2) is the copper melting point +20~50℃, and the stirring time is 15-45min; the heating temperature of solid copper in step (3) is the copper melting point +20~50℃, and the stirring time is 15-45min.

5. The method for preparing a corrosion-resistant nickel-clad copper strip according to claim 1, characterized in that, In step 2), the spray width is 0-50 mm and the spray flow rate is 0-5 g·s. -1 The initial rolling speed is 0.2~2 cm·s. -1 The rolling mill is kept at a constant temperature of 25°C; when the liquid copper is deposited onto the nickel strip, 30%-70% is in a liquid state; the liquid copper particle size distribution is between 20um and 200um, and the proportion of particles larger than 100um is >50%; the liquid copper is atomized by gas atomization or centrifugal atomization; the length and width of the copper jet deposition are smaller than the length and width of the nickel strip, respectively.

6. The method for preparing a corrosion-resistant nickel-clad copper strip according to claim 1, characterized in that, In step 3), the linear speed of the rolls is 1~3 cm·s. -1 The rolls are kept at a constant temperature of 25℃, and the rolling process is 1-20 times. The deformation of the nickel-plated copper strip is less than 40% each time. The annealing temperature is 400-700℃, and the holding time is 2-4 hours.

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