Graphene aluminum-based alloy busbar and forming method thereof

Abstract

The invention relates to the technical field of graphene aluminum-based alloy busbars, in particular to a graphene aluminum-based alloy busbar and a forming method thereof. A graphene aluminum-based alloy busbar comprises a graphene aluminum-based alloy, a transition layer coating the surface of the graphene aluminum-based alloy, and an outer surface layer coating the surface of the transition layer. The graphene aluminum base alloy contains 0.65 wt%-0.75 wt% of graphene. The transition layer comprises the following raw material components in percentage by weight: 0.4-0.6% of graphene, 2-5% of aluminum oxide and the balance of aluminum; the outer surface layer is prepared from the following raw material components in percentage by weight: 0.2 to 0.3 percent of graphene and the balance of aluminum; the problem that the quality of the busbar is affected by a traditional welding process is solved through a large-scale roller hot rolling forming technology, due to hot rolling forming, no gap exists in the joint face, the possibility of electrochemical corrosion is eradicated, the peel strength of the joint face is high, all layers are not prone to being separated, and performance is better.

Description

Technical Field

[0001] The present application relates to the technical field of graphene aluminum-based alloy busbars, and in particular to a graphene aluminum-based alloy busbar and a forming method thereof. Background Art

[0002] As a new conductive material, graphene aluminum-based alloy busbars offer significant advantages in power transmission due to their high thermal conductivity and lightweight properties. However, existing technologies commonly use welding to connect conductors to copper / aluminum connectors, which has the following drawbacks: Low interface bonding strength: Traditional welding makes it difficult to achieve metallurgical bonding between the graphene aluminum matrix and the connector. Since graphene is easily agglomerated in the aluminum matrix, unfused areas or pores are easily formed at the welding interface, resulting in reduced interface bonding strength.

[0003] Thermal expansion mismatch cracking: Due to the difference in thermal expansion between the graphene aluminum matrix and the connecting parts, the weld is subjected to alternating thermal stress under the cyclic temperature rise generated by the current load, which makes it easy to crack.

[0004] Oxidation and corrosion sensitivity: High-temperature welding causes oxidation of the graphene-aluminum interface, and residual electrolyte corrosion pits in the welding accelerate electrochemical corrosion.

[0005] Therefore, there are certain safety hazards when using busbars prepared by traditional welding technology. Therefore, how to effectively solve the impact of traditional welding technology on the quality of busbars has become an urgent problem to be solved. Summary of the Invention

[0006] In response to the deficiencies in the prior art, the present application provides a graphene aluminum-based alloy busbar and a forming method thereof.

[0007] In a first aspect, the present application provides a graphene aluminum-based alloy busbar and a forming method thereof, which adopts the following technical solutions: A graphene aluminum-based alloy busbar, comprising a graphene aluminum-based alloy, a transition layer coated on the surface of the graphene aluminum-based alloy, and an outer layer coated on the surface of the transition layer; The graphene aluminum-based alloy contains 0.65-0.75 wt% of graphene; The transition layer comprises the following raw material components in weight percentage: 0.4-0.6% graphene, 2-5% alumina, and the balance is aluminum; the outer layer comprises the following raw material components in weight percentage: 0.2-0.3% graphene, and the balance is aluminum.

[0008] In a specific embodiment, the graphene aluminum-based alloy includes the following raw material components in weight percentage: silicon 0.02-0.15%, iron 0.2-1.0%, copper 0.1-0.40%, vanadium 0.01-0.08%, graphene 0.65-0.75%, zirconium 0.04-0.06%, boron 0.05-0.08%, rare earth 0.02-0.5%, and the balance is aluminum and impurities.

[0009] By adopting the above technical solution, the graphene aluminum-based alloy busbar disclosed in the present application includes a graphene aluminum-based alloy, a transition layer and an outer layer arranged in sequence from the inside to the outside, the graphene concentration in the graphene aluminum-based alloy is 0.65-0.75wt%, the graphene concentration in the transition layer is 0.4-0.6wt%, and the graphene concentration in the outer layer is 0.2-0.3wt%; the present application realizes material functional partitioning through spatial concentration gradient design, and the addition of high concentration of graphene to the graphene aluminum-based alloy can effectively improve the conductivity of the graphene aluminum-based alloy busbar; the addition of medium concentration of graphene to the transition layer forms a stress buffer layer through the decreasing concentration gradient, effectively improving the tensile strength of the graphene aluminum-based alloy busbar while maintaining the resistivity; the addition of low concentration of graphene to the outer layer can retain the ductility of the aluminum matrix, improve the toughness of the product, and extend the bending fatigue life; the present application realizes material functional partitioning through spatial concentration gradient design, which can eliminate stress concentration caused by material interface mutation and improve the comprehensive performance of the product.

[0010] Preferably, the porosity of the graphene in the transition layer is 0.2-0.3%; the pore particle size of the graphene in the transition layer is 12-14 μm.

[0011] Preferably, the porosity of the graphene in the outer layer is 1.4-1.6%; the pore particle size of the graphene in the outer layer is 8-10 μm.

[0012] By adopting the above technical solution, the porosity of graphene and the pore particle size of graphene have an impact on the thermal conductivity of the busbar. As the porosity increases, the thermal conductivity tends to decrease; as the pore particle size increases, the thermal conductivity becomes larger and larger. In this application, by further limiting the porosity and pore particle size of graphene in the transition layer and the outer layer, the transition layer can quickly conduct the heat generated by current transmission, thereby reducing the temperature of the graphene aluminum-based alloy; the outer layer can slow down the heat transfer rate, reduce the difference in thermal expansion coefficient at the material interface, and reduce thermal cycling stress.

[0013] In this application, by limiting the porosity and pore size of graphene in the transition layer and the outer layer, graphene forms a stable three-dimensional thermal conductive network in the aluminum matrix, further improving the thermal stability and thermal fatigue resistance of the graphene aluminum-based alloy busbar.

[0014] Preferably, the aluminum oxide in the transition layer is aluminum oxide modified with graphene oxide, and the modification steps are as follows: adding graphene oxide to water to obtain a graphene oxide colloidal solution; Alumina was added to water, and an acidic reagent was added to adjust the pH to 3.3 to obtain an alumina colloidal solution; Alumina colloidal solution is added dropwise to the graphene oxide colloidal solution, mixed, and freeze-dried to obtain graphene oxide-modified aluminum oxide.

[0015] Preferably, the mass ratio of graphene oxide to aluminum oxide is (3-5):6.

[0016] Preferably, the concentration of the graphene oxide colloidal solution is 0.4×10 -3 g / mL-0.6×10 -3 g / mL; the concentration of the alumina colloidal solution is 4.5×10 -3 g / mL-5.5×10 -3 g / mL.

[0017] By adopting the above-mentioned technical solution, graphene oxide is used in this application to modify alumina to prepare a composite reinforcement phase, which not only effectively avoids the aggregation of alumina, but also significantly improves the dispersibility of the reinforcement phase, and evenly disperses the composite reinforcement phase into the transition layer raw material, thereby improving the mechanical properties of the transition layer and further improving the mechanical properties of the graphene aluminum-based alloy busbar.

[0018] In a second aspect, the present application provides a method for preparing a graphene aluminum-based alloy busbar, which adopts the following technical solution: A method for preparing a graphene aluminum-based alloy busbar, the preparation method comprising the following steps: (1) Weigh each raw material according to the formula; (2) Preparation of transition layer raw materials: After mixing graphene and alumina, ball milling is performed to obtain a mixed powder; The raw aluminum ingot is added into the smelting furnace for smelting to obtain molten aluminum liquid, and then the mixed powder is added and mixed to obtain the transition layer raw material solution; (3) Preparation of outer layer raw materials: The raw aluminum ingot is added into a smelting furnace for smelting to obtain molten aluminum liquid, and then graphene is added and mixed to obtain a surface layer raw material solution; (4) Preparation of busbar: Step 1: Stretch the graphene aluminum-based alloy and then roll it into a sheet to obtain a graphene aluminum-based alloy sheet; Step 2: Four graphene aluminum-based alloy sheets are uncoiled on an uncoiler, two of which are closely attached to the upper roll of the twin-roll casting equipment, and the other two are closely attached to the lower roll of the twin-roll casting equipment, with the interval between the graphene aluminum-based alloy sheets on the same roll being the sleeve width; Step 3: The molten transition layer raw material solution is injected into the gap between the upper and lower rollers through the casting nozzle under static pressure. The injection width is the sum of the width of the graphene aluminum-based alloy sheets on both sides of the rollers and the distance between them. Step 4: The upper and lower rollers cool the graphene aluminum-based alloy sheet coated with the transition layer and solid-liquid casting and rolling to form a first composite slab; Step 5: The four first composite slabs are uncoiled on the uncoiler respectively, two of which are closely attached to the upper rolls of the twin-roll casting equipment, and the other two are closely attached to the lower rolls of the twin-roll casting equipment, with the first composite slabs on the same rolls spaced apart by the sleeve width; Step 6: injecting the molten outer surface layer raw material solution into the gap between the upper and lower rollers through the casting nozzle under static pressure, with the injection width being the sum of the width of the first composite slab on both sides of the rollers and the distance between them; Step 7: The upper and lower rollers cool the first composite slab and perform solid-liquid casting to form a second composite slab; Step 8: placing the second composite slab into an annealing furnace for homogenization annealing; Step 9: The length of the second composite slab is the length of the roller rolling. After annealing, the second composite slab is cut in the width direction according to the final product specifications and the requirements of subsequent steps; Step 10: continuously cold rolling the second composite slab; Step 11: The second composite slab is introduced into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting. Slitting is performed according to the product size; Step 12: The second composite slab after stripping is straightened and leveled, and then chamfered by a chamfering device. After chamfering, it is straightened and leveled again to obtain a graphene aluminum-based alloy busbar.

[0019] Preferably, in step 3, the transition layer raw material solution is heated to 700-740° C. to obtain a molten transition layer raw material solution.

[0020] Preferably, in step 6, the outer surface layer raw material solution is heated to 700-740° C. to obtain a molten outer surface layer raw material solution.

[0021] Preferably, in step 8, during annealing, the heating temperature is 350° C.-450° C., and the annealing time is 15 h-30 h.

[0022] By adopting the above technical solution, the transition layer and the outer layer in the present application are sequentially injected into the surface of the graphene aluminum-based alloy and formed by hot rolling. There is no gap between the bonding surfaces of the graphene aluminum-based alloy and the transition layer and the outer layer, which eliminates the possibility of electrochemical corrosion. The bonding surface has high peeling strength, and the bonding surfaces are not easy to separate, resulting in better performance, improving the reliability of the busbar, and improving the connection performance of the busbar. In addition, the conductive performance and mechanical properties are far superior to those of existing welded busbars.

[0023] In summary, this application includes at least one of the following beneficial technical effects: This application discloses a graphene aluminum-based alloy busbar and its forming method. This application realizes material functional partitioning through spatial concentration gradient design, which can eliminate stress concentration caused by material interface mutation and improve the product's electrical conductivity and mechanical properties. This application solves the problem of the traditional welding process affecting the quality of the busbar through large-scale roller hot rolling forming technology. Due to hot rolling forming, there is no gap on the bonding surface, eliminating the possibility of electrochemical corrosion. The bonding surface has high peeling strength, the layers are not easy to separate, and the performance is better. DETAILED DESCRIPTION

[0024] The technical solution of the present application is further illustrated below through specific embodiments. The specific embodiments do not limit the scope of protection of the present application; some non-essential modifications and adjustments made by others based on the concept of the present application still fall within the scope of protection of the present application.

[0025] The raw materials involved in this application are all commercially available products, among which: Graphene oxide, purity of 99.9%, sheet diameter of 1-5 μm, number of layers of 1-2, C<45%, O>54%, S<1%.

[0026] The present application is further described in detail below with reference to the following examples and comparative examples.

[0027] Preparation Example 1: The steps for modifying the alumina in the transition layer are as follows: 4 kg of graphene oxide was added to deionized water and ultrasonically dispersed for 5 hours to obtain a concentration of 0.5×10 -3 g / mL graphene oxide colloidal solution, the solution is negatively charged; 6 kg of alumina powder was added to deionized water, and 1 M hydrochloric acid solution was added to adjust the pH to 3.3 to make the surface of alumina positively charged. Then ultrasonic treatment was performed for 2 hours to obtain a concentration of 5×10 -3 g / mL alumina colloidal solution; The graphene oxide colloidal solution was placed on the tray of a magnetic stirrer, and the alumina colloidal solution was added dropwise while stirring. After mixing for 1 hour, the mixed solution was quickly frozen with liquid nitrogen and placed in a freeze dryer to obtain a composite powder, which is alumina modified with graphene oxide.

[0028] Preparation Example 2: The steps for modifying the alumina in the transition layer are as follows: 3 kg of graphene oxide was added to deionized water and ultrasonically dispersed for 5 hours to obtain a concentration of 0.4×10 -3 g / mL graphene oxide colloidal solution, the solution is negatively charged; 6 kg of alumina powder was added to deionized water, and 1 M hydrochloric acid solution was added to adjust the pH to 3.3 to make the surface of alumina positively charged. Then ultrasonic treatment was performed for 2 hours to obtain a concentration of 4.5×10 -3 g / mL alumina colloidal solution; The graphene oxide colloidal solution was placed on the tray of a magnetic stirrer, and the alumina colloidal solution was added dropwise while stirring. After mixing for 1 hour, the mixed solution was quickly frozen with liquid nitrogen and placed in a freeze dryer to obtain a composite powder, which is alumina modified with graphene oxide.

[0029] Preparation Example 3: The steps for modifying the alumina in the transition layer are as follows: 5 kg of graphene oxide was added to deionized water and ultrasonically dispersed for 5 hours to obtain a concentration of 0.6×10 -3 g / mL graphene oxide colloidal solution, the solution is negatively charged; 6 kg of alumina powder was added to deionized water, and 1 M hydrochloric acid solution was added to adjust the pH to 3.3 to make the surface of alumina positively charged. Then ultrasonic treatment was performed for 2 hours to obtain a concentration of 5.5×10 -3 g / mL alumina colloidal solution; The graphene oxide colloidal solution was placed on the tray of a magnetic stirrer, and the alumina colloidal solution was added dropwise while stirring. After mixing for 1 hour, the mixed solution was quickly frozen with liquid nitrogen and placed in a freeze dryer to obtain a composite powder, which is alumina modified with graphene oxide.

[0030] Example 1: A graphene aluminum-based alloy busbar comprises a graphene aluminum-based alloy, a transition layer coated on the surface of the graphene aluminum-based alloy, and an outer layer coated on the surface of the transition layer; the graphene aluminum-based alloy busbar is 3 meters long and 10 mm thick; the graphene aluminum-based alloy sheet is 20 cm long and 1.5 mm thick.

[0031] The preparation method of the graphene aluminum-based alloy busbar comprises the following steps: Step 1: Preparation of graphene aluminum-based alloy The graphene aluminum-based alloy includes the following components in weight percentage (%): 0.14% silicon, 0.9% iron, 0.4% copper, 0.08% vanadium, 0.7% graphene, 0.06% zirconium, 0.08% boron, 0.02% lanthanum, 0.01% scandium, and the balance is aluminum and impurities.

[0032] The above-mentioned method for preparing graphene aluminum-based alloy comprises the following steps: (1) Melting: Weigh the raw materials of corresponding composition according to the composition of the aluminum-based composite conductor, put the aluminum raw material into a crucible, heat it to 750°C, add the remaining raw materials and continue stirring to form a uniform melt; (2) Refining: Maintaining the temperature at 750°C, in an inert protective atmosphere of Ar, adding refining agents for refining; after the refining is completed, the slag removal operation is carried out; (3) Degassing of holding furnace In the heat preservation state, a mixed gas is introduced into the melt for degassing; (4) Casting and continuous casting The melt is cast and continuously cast to obtain aluminum-based alloy rods, and the total cooling rate during the casting process is controlled to be 12°C / s; (5) Tempering treatment The aluminum-based alloy rod is placed in a toughening furnace at a toughening temperature of 370°C and a toughening time of 5 hours. (6) Wire drawing and aging treatment The aluminum-based alloy rod after annealing treatment is subjected to wire drawing treatment and then put into aging furnace for aging treatment; (7) Bundle twisting and re-twisting The aluminum-based alloy wire bundles are twisted and re-twisted to finally obtain graphene aluminum-based alloy.

[0033] Wherein, in the refining process in step (2), permanent magnetic stirring is performed every 15 minutes, and each stirring time is 5 minutes.

[0034] Wherein, the mixed gas in step (3) is 80 vol% Ar and 20 vol% Cl2.

[0035] Wherein, in step (6), the wire drawing diameter is Ф0.5 mm, the aging treatment temperature is 190° C., and the aging treatment time is 5 h.

[0036] The properties of the prepared graphene aluminum-based alloy were tested, and the ZrB2 phase was 0.0017wt%, the nano-Al3Zr dispersed phase was 0.0028wt%, the crystal size was 49.4μm, the tensile strength was 165.4MPa, and the conductivity was 64.1% IACS.

[0037] Step 2: Preparation of transition layer raw materials: 0.5 wt% of graphene and 3.5 wt% of modified alumina were mixed, poured into a ball mill, and ball milled at 200 rpm for 1 hour (the mass ratio of grinding balls to powder was 6:1). The mixture was then dried at 60°C for 0.5 hour and passed through an 80-mesh sieve to obtain a mixed powder. The modified aluminum oxide is aluminum oxide modified with graphene oxide, and is prepared according to Preparation Example 1.

[0038] The porosity of the graphene in the transition layer is 0.25%; the pore particle size of the graphene in the transition layer is 13 μm.

[0039] The raw aluminum ingots are added to a smelting furnace for smelting treatment and heated to 700-740°C to obtain molten aluminum liquid; the mixed powder is then added and continuously stirred to form a uniform melt, and the molten aluminum liquid is poured into a holding furnace, the temperature is controlled at 700-740°C, and the furnace is kept warm and allowed to stand for 20-60 minutes to obtain a transition layer raw material solution; the raw aluminum ingots are aluminum materials of models 1G20, 1050, 1060, and 1100, and the aluminum content is greater than 99.2%.

[0040] The transition layer raw material solution after heat preservation and static is degassed and filtered through online processing equipment such as a degassing box and a filter box.

[0041] Step 3: Preparation of outer layer raw materials: The raw aluminum ingots are added to a smelting furnace for smelting treatment and heated to 700-740°C to obtain molten aluminum liquid; 0.25wt% graphene is then added and continuously stirred to form a uniform melt. The molten aluminum liquid is poured into a holding furnace, the temperature is controlled at 700-740°C, and the furnace is kept warm and allowed to stand for 20-60 minutes to obtain a transition layer raw material solution; the raw aluminum ingots are aluminum materials of models 1G20, 1050, 1060, and 1100, and the aluminum content is greater than 99.2%.

[0042] The outer surface layer raw material solution after heat preservation and standing is degassed and filtered through online processing equipment such as degassing box and filter box.

[0043] The porosity of the graphene in the outer layer is 1.5%; the pore particle size of the graphene in the outer layer is 9 μm.

[0044] Step 4: Preparation of busbar: Step 1: The graphene aluminum alloy is stretched and finished, and then the graphene aluminum alloy is rolled into a sheet to obtain a graphene aluminum alloy sheet with a length of 20 cm and a thickness of 1.5 mm; Before unwinding, the graphene aluminum alloy sheet is first rinsed with water at high pressure, and then rinsed at low pressure. The rinse liquid is an alkaline degreasing liquid at 50°C for degreasing to remove grease on the surface of the graphene aluminum alloy sheet. Finally, the surface of the graphene aluminum alloy sheet is polished with a steel brush equipment to increase the roughness of the surface of the graphene aluminum alloy sheet and increase the composite area of the graphene aluminum alloy sheet, thereby enhancing the bonding ability of the composite material.

[0045] Step 2: Four graphene aluminum-based alloy sheets are uncoiled on an uncoiler, two of which are closely attached to the upper roll of the twin-roll casting equipment, and the other two are closely attached to the lower roll of the twin-roll casting equipment, with the interval between the graphene aluminum-based alloy sheets on the same roll being the sleeve width; Four graphene aluminum-based alloy sheets are wound on the rolling rollers in opposite directions from the injection direction of the casting nozzle. At the same time, each graphene aluminum-based alloy sheet is equipped with a tensioning roller and a pressure roller. The speed of the graphene aluminum-based alloy sheet is adjusted by the tensioning roller and the pressure roller to ensure that the speed of the four graphene aluminum-based alloy sheets winding around the rolling roller is consistent. At the same time, the pressure roller ensures that the graphene aluminum-based alloy sheet is tightly attached to the rolling roller when entering the hot rolling area. There is also a heating roller on one side of the casting nozzle. Usually, one graphene aluminum-based alloy sheet is equipped with a heating roller. The heating roller is close to the hot rolling area and heats the graphene aluminum-based alloy sheet to 150°C.

[0046] Step 3: Inject the molten transition layer raw material solution into the gap between the upper and lower rollers under static pressure through a casting nozzle. The injection width is the sum of the width of the graphene aluminum-based alloy sheets on both sides of the rollers and the distance between them.

[0047] Step 4: The upper and lower rollers cool the transition layer-coated graphene aluminum alloy sheet and solid-liquid cast it to form a first composite slab. Simultaneously, the upper and lower rollers cool the first composite slab at a cooling rate of 300°C / s. Water is used as the coolant in the upper and lower rollers, and the water temperature is maintained at 20°C. When the transition layer raw material solution is injected through the casting nozzle, it rapidly cools and solidifies upon contact with the rollers. Similarly, upon contact with the graphene aluminum alloy sheet, the transition layer raw material solution also rapidly cools. The transition layer raw material solution crystallizes in contact with the upper and lower graphene aluminum alloy sheets in the casting zone, with heat removed by the cooling water circulating through the rollers.

[0048] Step 5: The four first composite slabs are uncoiled on the uncoiler respectively, two of which are closely attached to the upper rolls of the twin-roll casting equipment, and the other two are closely attached to the lower rolls of the twin-roll casting equipment, with the first composite slabs on the same rolls spaced apart by the sleeve width; The four first composite slabs are wound on the rolling rollers in opposite directions from the injection direction of the casting nozzle. At the same time, each first composite slab is equipped with a tensioning roller and a pressure roller. The speed of the first composite slab is adjusted by the tensioning roller and the pressure roller to ensure that the speed of the four first composite slabs winding around the rolling rollers is consistent. At the same time, the pressure roller ensures that the first composite slab is tightly attached to the rolling roller when entering the hot rolling area. There is also a heating roller on one side of the casting nozzle. Usually, one first composite slab is equipped with a heating roller. The heating roller is close to the hot rolling area. The heating roller heats the first composite slab to 150°C.

[0049] Step 6: Inject the molten outer surface layer raw material solution into the gap between the upper and lower rollers under static pressure through the casting nozzle. The injection width is the sum of the width of the first composite slab on both sides of the rollers and the distance between them.

[0050] Step 7: The upper and lower rollers cool the first composite slab coated with the outer layer raw material solution and solid-liquid cast it to form a second composite slab. Simultaneously, the upper and lower rollers cool the second composite slab at a cooling rate of 300°C / s. Water is used as the coolant in the upper and lower rollers, and the water temperature is maintained at 20°C. When the outer layer raw material solution is injected through the casting nozzle, it rapidly cools and solidifies upon contact with the rollers. Similarly, the outer layer raw material solution rapidly cools upon contact with the second composite slab. The outer layer raw material solution crystallizes in the casting zone in contact with the upper and lower second composite slabs, and heat is removed by the cooling water circulating through the rollers.

[0051] Step 8: Place the second composite slab into an annealing furnace for homogenization annealing at a heating temperature of 400° C. for 20 hours.

[0052] Step 9: The length of the second composite slab is the length of the roller rolling. After annealing, the second composite slab is cut in the width direction according to the final product specifications and the requirements of subsequent steps.

[0053] Step 10: Make the movement direction of the second composite slab in the length direction consistent with the tangential rolling direction of the cold rolling mill roller, and then continuously cold roll the second composite slab to extend the slab length to the required specifications. The total cold rolling reduction rate is 20%, and the rolling force is not less than 600t.

[0054] Step 11: Introduce the second composite slab into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting, and slitting is performed according to the product size.

[0055] Step 12: The second composite slab after stripping is straightened and leveled, and then chamfered by chamfering equipment. After chamfering, it is straightened and leveled again.

[0056] Example 2: The difference from Example 1 is that the raw materials are different.

[0057] In this embodiment, the graphene aluminum-based alloy contains 0.65 wt% of graphene; The transition layer comprises the following raw material components: 0.4 wt% graphene, 2 wt% modified alumina, and the balance aluminum; The outer layer comprises the following raw material components: 0.2 wt% graphene and the balance aluminum.

[0058] The modified alumina is alumina modified with graphene oxide, and is prepared according to Preparation Example 2.

[0059] Example 3: The difference from Example 1 is that the raw materials are different.

[0060] In this embodiment, the graphene aluminum-based alloy contains 0.75 wt% of graphene; The transition layer comprises the following raw material components: 0.6 wt% graphene, 5 wt% modified alumina, and the balance aluminum; The outer layer comprises the following raw material components: 0.3 wt% graphene and the balance aluminum.

[0061] The modified alumina is alumina modified with graphene oxide, and is prepared according to Preparation Example 3.

[0062] Example 4: The difference from Example 1 is that the porosity of the graphene in the transition layer is 0.2%; and the pore particle size of the graphene in the transition layer is 12 μm.

[0063] Example 5: The difference from Example 1 is that the porosity of the graphene in the transition layer is 0.3%; and the pore particle size of the graphene in the transition layer is 14 μm.

[0064] Example 6: The difference from Example 1 is that the porosity of the graphene in the outer layer is 1.4%; and the pore particle size of the graphene in the outer layer is 8 μm.

[0065] Example 7: The difference from Example 1 is that the porosity of the graphene in the outer layer is 1.6%; the pore particle size of the graphene in the outer layer is 10 μm.

[0066] Comparative Example 1: The difference from Example 1 is that the raw materials of the transition layer are different.

[0067] In this comparative example, the filter layer raw material includes the following raw material components: 0.5 wt % graphene, 3.5 wt % aluminum oxide, and the balance is aluminum.

[0068] Comparative Example 2: The difference from Example 2 is that the raw materials of the transition layer are different.

[0069] In this comparative example, the transition layer comprises the following raw material components: 0.4 wt % graphene, 2 wt % aluminum oxide, and the balance is aluminum.

[0070] Comparative Example 3: The difference from Example 3 is that the raw materials of the transition layer are different.

[0071] In this comparative example, the transition layer comprises the following raw material components: 0.6 wt % graphene, 5 wt % aluminum oxide, and the balance is aluminum.

[0072] Comparative Example 4: The difference from Example 1 is that the porosity of the graphene in the transition layer is 0.1%; and the pore particle size of the graphene in the transition layer is 11 μm.

[0073] Comparative Example 5: The difference from Example 1 is that the porosity of the graphene in the transition layer is 0.4%; and the pore particle size of the graphene in the transition layer is 15 μm.

[0074] Comparative Example 6: The difference from Example 1 is that the porosity of the graphene in the outer layer is 1.3%; the pore particle size of the graphene in the outer layer is 7 μm.

[0075] Comparative Example 7: The difference from Example 1 is that the porosity of the graphene in the outer layer is 1.7%; the pore particle size of the graphene in the outer layer is 11 μm.

[0076] Performance testing: The performance of the samples prepared in the above examples and comparative examples was tested, and the test results are as follows: (1) Tensile strength and elongation: The test method refers to the standard GB / T 16865-2023. The samples prepared in the above examples and comparative examples were processed into standard tensile specimens, and the tensile mechanical properties were tested on an electronic tensile testing machine. The test environment temperature was 25°C, the tensile rate was 2 mm / min, and each group of samples was tested three times and the average value was taken.

[0077] (2) Durability test: The durability of the samples was tested at 650°C and a load of 700 MPa.

[0078] (3) Fatigue strength performance test: According to GBT 43371984 "Metal Rotational Bending Fatigue Test Method", the maximum fatigue strength of the sample is tested at 650°C. (4) Resistance and conductivity are tested according to conventional testing methods.

[0079] Table 1 Performance test results Combined with the data in Table 1, it can be seen that the graphene aluminum-based alloy busbar prepared in the present application has good electrical conductivity, tensile strength, and elongation, as well as good durability and fatigue resistance.

[0080] Combining the test results of Example 1 and Comparative Example 1, it can be seen that the tensile strength and elongation of Example 1 are better than those of Comparative Example 1, indicating that the aluminum oxide used is modified aluminum oxide, that is, aluminum oxide modified with graphene oxide, which effectively improves the mechanical properties of the busbar.

[0081] Combining the test results of Example 2 and Comparative Example 2, it can be seen that the tensile strength and elongation of Example 2 are better than those of Comparative Example 2, indicating that the aluminum oxide used is modified aluminum oxide, that is, aluminum oxide modified with graphene oxide, which effectively improves the mechanical properties of the busbar.

[0082] Combining the test results of Example 3 and Comparative Example 3, it can be seen that the tensile strength and elongation of Example 3 are better than those of Comparative Example 3, indicating that the aluminum oxide used is modified aluminum oxide, that is, aluminum oxide modified with graphene oxide, which effectively improves the mechanical properties of the busbar.

[0083] Combined with the test results of Examples 1, 4, 5, and Comparative Examples 4 and 5, it can be seen that the porosity and pore particle size of the graphene in the transition layer have a certain influence on the thermal stability and thermal fatigue resistance of the busbar, and when the porosity of the graphene in the transition layer is 0.2-0.3% and the pore particle size of the graphene is 12-14 μm, the thermal stability and thermal fatigue resistance of the busbar are optimal.

[0084] Combined with the test results of Examples 1, 6, 7, and Comparative Examples 6 and 7, it can be seen that the porosity of the graphene in the outer layer and the pore particle size of the graphene have a certain influence on the thermal stability and thermal fatigue resistance of the busbar. When the porosity of the graphene in the outer layer is 1.4-1.6% and the pore particle size of the graphene is 8-10 μm, the thermal stability and thermal fatigue resistance of the busbar are optimal.

Claims

1. A graphene aluminum-based alloy busbar, characterized by: It includes a graphene aluminum-based alloy, a transition layer coated on the surface of the graphene aluminum-based alloy, and an outer layer coated on the surface of the transition layer; The graphene aluminum-based alloy contains 0.65-0.75 wt% of graphene; The transition layer comprises the following raw material components in weight percentage: 0.4-0.6% graphene, 2-5% alumina, and the balance aluminum; The outer layer comprises the following raw material components in the following weight percentages: 0.2-0.3% graphene, and the balance is aluminum.

2. The graphene aluminum-based alloy busbar according to claim 1, characterized in that: The porosity of the graphene in the transition layer is 0.2-0.3%; the pore particle size of the graphene in the transition layer is 12-14 μm.

3. The graphene aluminum-based alloy busbar according to claim 1, characterized in that: The porosity of the graphene in the outer layer is 1.4-1.6%; the pore particle size of the graphene in the outer layer is 8-10 μm.

4. The graphene aluminum-based alloy busbar according to claim 1, characterized in that: The aluminum oxide in the transition layer is aluminum oxide modified with graphene oxide, and the modification steps are as follows: adding graphene oxide to water to obtain a graphene oxide colloidal solution; Alumina was added to water, and an acidic reagent was added to adjust the pH to 3.3 to obtain an alumina colloidal solution; Alumina colloidal solution is added dropwise to the graphene oxide colloidal solution, mixed, and freeze-dried to obtain graphene oxide-modified aluminum oxide.

5. The graphene aluminum-based alloy busbar according to claim 4, characterized in that: The mass ratio of the graphene oxide to aluminum oxide is (3-5):

6.

6. The graphene aluminum-based alloy busbar according to claim 4, characterized in that: The concentration of the graphene oxide colloidal solution is 0.4×10 -3 g / mL-0.6×10 -3 g / mL; the concentration of the alumina colloidal solution is 4.5×10 -3 g / mL-5.5×10 -3 g / mL.

7. A method for preparing the graphene aluminum-based alloy busbar according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) Weigh the raw materials according to the formula; (2) Preparation of transition layer raw materials: After mixing graphene and alumina, ball milling is performed to obtain a mixed powder; The raw aluminum ingot is added into the smelting furnace for smelting to obtain molten aluminum liquid, and then the mixed powder is added and mixed to obtain the transition layer raw material solution; (3) Preparation of outer layer raw materials: The raw aluminum ingot is added into a smelting furnace for smelting to obtain molten aluminum liquid, and then graphene is added and mixed to obtain a surface layer raw material solution; (4) Preparation of busbar: Step 1: Stretch the graphene aluminum-based alloy and then roll it into a sheet to obtain a graphene aluminum-based alloy sheet; Step 2: Four graphene aluminum-based alloy sheets are uncoiled on an uncoiler, two of which are closely attached to the upper roll of the twin-roll casting equipment, and the other two are closely attached to the lower roll of the twin-roll casting equipment, with the interval between the graphene aluminum-based alloy sheets on the same roll being the sleeve width; Step 3: The molten transition layer raw material solution is injected into the gap between the upper and lower rollers through the casting nozzle under static pressure. The injection width is the sum of the width of the graphene aluminum-based alloy sheets on both sides of the rollers and the distance between them. Step 4: The upper and lower rollers cool the graphene aluminum-based alloy sheet coated with the transition layer and solid-liquid casting and rolling to form a first composite slab; Step 5: The four first composite slabs are uncoiled on the uncoiler respectively, two of which are closely attached to the upper rolls of the twin-roll casting equipment, and the other two are closely attached to the lower rolls of the twin-roll casting equipment, with the first composite slabs on the same rolls spaced apart by the sleeve width; Step 6: injecting the molten outer surface layer raw material solution into the gap between the upper and lower rollers through the casting nozzle under static pressure, with the injection width being the sum of the width of the first composite slab on both sides of the rollers and the distance between them; Step 7: The upper and lower rollers cool the first composite slab and perform solid-liquid casting to form a second composite slab; Step 8: placing the second composite slab into an annealing furnace for homogenization annealing; Step 9: The length of the second composite slab is the length of the roller rolling, and the second composite slab is cut after annealing; Step 10: continuously cold rolling the second composite slab; Step 11: The second composite slab is introduced into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting. Slitting is performed according to the product size; Step 12: Straighten, level, and chamfer the second composite slab after stripping to obtain a graphene aluminum-based alloy busbar.

8. The method for preparing a graphene aluminum-based alloy busbar according to claim 7, wherein: In step 3, the transition layer raw material solution is heated to 700-740° C. to obtain a molten transition layer raw material solution.

9. The method for preparing a graphene aluminum-based alloy busbar according to claim 7, wherein: In step 6, the outer surface layer raw material solution is heated to 700-740° C. to obtain a molten outer surface layer raw material solution.

10. The method for preparing a graphene aluminum-based alloy busbar according to claim 7, wherein: In step 8, during annealing, the heating temperature is 350° C.-450° C., and the annealing time is 15 h-30 h.

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